Showing papers in "International Journal of Oncology in 2008"
TL;DR: A general overview of the nuclear functions and regulation of the HMGA genes and corresponding proteins is given.
Abstract: The 'high mobility group' HMGA protein family consists of four members: HMGA1a, HMGA1b and HMGA1c, which result from translation of alternative spliced forms of one gene and HMGA2, which is encoded for by another gene. HMGA proteins are characterized by three DNA-binding domains, called AT-hooks, and an acidic carboxy-terminal tail. HMGA proteins are architectural transcription factors that both positively and negatively regulate the transcription of a variety of genes. They do not display direct transcriptional activation capacity, but regulate gene expression by changing the DNA conformation by binding to AT-rich regions in the DNA and/or direct interaction with several transcription factors. In this way, they influence a diverse array of normal biological processes including cell growth, proliferation, differentiation and death. Both HMGA1 and HMGA2 are hardly detectable in normal adult tissue but are abundantly and ubiquitously expressed during embryonic development. In malignant epithelial tumors as well as in leukemia, however, expression of HMGA1 is again strongly elevated to embryonic levels thus leading to ectopic expression of (fetal) target genes. HMGA2 overexpression also has a causal role in inducing neoplasia. Besides overexpression of full length HMGA proteins in different tumors, the HMGA genes are often involved in chromosomal rearrangements. Such translocations are mostly detected in benign tumors of mesenchymal origin and are believed to be one of the most common chromosomal rearrangements in human neoplasia. To provide clarity in the abundance of articles on this topic, this review gives a general overview of the nuclear functions and regulation of the HMGA genes and corresponding proteins.
273 citations
TL;DR: The accumulated evidence suggests that the effectiveness of immune-based therapies for solid tumors may be enhanced by selective antagonism of the adenosine receptor subtypes through whichadenosine inhibits the anti-tumor activity of T lymphocytes and NK cells.
Abstract: The resistance of many human cancers to immune-based therapies, including adoptive immunotherapy and the administration of therapeutic cancer vaccines, has been attributed to tumor-associated immune suppression, due in part to immunosuppressive molecules located within the tumor microenvironment. Adenosine is a purine nucleoside found within the interstitial fluid of solid tumors at concentrations that are able to inhibit cell-mediated immune responses to tumor cells. It is well established that extracellular adenosine inhibits T lymphocyte activation and effector function, including T cell adhesion to tumor cells and cytotoxic activity, by signaling primarily through A2a and A3 adenosine receptors on the surface of T cells. Importantly, A2a adenosine receptor-deficient mice exhibit enhanced anti-tumor immune responses by CD8+ T cells, as well as a dramatic reduction in the growth of experimental tumors in comparison to wild-type controls. A2a adenosine receptor signaling has also been implicated in adenosine-mediated inhibition of cytokine production and cytotoxic activity by activated natural killer (NK) cells, although the process of NK cell granule exocytosis is apparently suppressed via a distinct and as yet uncharacterized adenosine receptor. In this report, we review the evidence that adenosine is a potent inhibitor of cellular immune responses and may therefore be a major barrier to the successful immunotherapy of human carcinomas. The signaling pathways through which adenosine exerts its inhibitory effects on cell-mediated immune responses are also discussed. The accumulated evidence suggests that the effectiveness of immune-based therapies for solid tumors may be enhanced by selective antagonism of the adenosine receptor subtypes through which adenosine inhibits the anti-tumor activity of T lymphocytes and NK cells.
215 citations
TL;DR: NIR Raman spectroscopy in combination with a powerful SVM technique has great potential for providing an effective and accurate diagnostic schema for cancer diagnosis in the colon.
Abstract: The ability of combining near-infrared (NIR) Raman spectroscopy with support vector machines (SVM) for improving multi-class classification between different histopathological groups in tissues was evaluated in this study. A total of 105 colonic tissue specimens from 59 patients including 41 normal, 18 hyperplastic polyps and 46 adenocarcinomas were used for this purpose. A rapid-acquisition dispersive-type NIR Raman system was utilized for tissue Raman spectroscopic measurements at 785-nm laser excitation. A total of 817 tissue Raman spectra were acquired and subjected to principal components analysis (PCA) for SVM-based multi-class classification, in which 324 Raman spectra were from normal, 184 from polyps and 309 from adenocarcinomatous colonic tissue. Two types of SVM (i.e., C-SVM and nu-SVM) with three different kernel functions (linear, polynomial and Gaussian radial basis function (RBF) in combination with PCA were used to develop effective diagnostic algorithms for classification of Raman spectra of different colonic tissues. The performance of various SVM-based algorithms was evaluated and compared using a leave-one-out, cross-validation method. The results showed that in the C-SVM classification, the maximum overall diagnostic accuracy of 99.3, 99.4 and 99.9% can be achieved using the linear, polynomial and RBF kernels, respectively; while in the nu-SVM classification, the maximum overall diagnostic accuracy of 98.4, 98.5 and 99.6% can be obtained using the linear, polynomial and RBF kernels, respectively. All the polyps can be identified from normal and adenocarcinomatous tissue using the C-SVM algorithms. The RBF C-SVM algorithm was proven to be the best classifier for providing the highest diagnostic accuracy (99.9%) for multi-class classification. This study demonstrates that NIR Raman spectroscopy in combination with a powerful SVM technique has great potential for providing an effective and accurate diagnostic schema for cancer diagnosis in the colon.
177 citations
TL;DR: Studies to enhance targeted delivery of an anticancer agent, curcumin, for prostate cancer treatment by incorporating this agent into the liposomes (nanodelivery vehicles primarily composed of phospholipids) coated with prostate membrane specific antigen specific antibodies observe that LNCaP cells were relatively more sensitive to liposomalCurcumin mediated block of cellular proliferation than C4-2B cells.
Abstract: We have initiated studies to enhance targeted delivery of an anticancer agent, curcumin, for prostate cancer treatment by incorporating this agent into the liposomes (nanodelivery vehicles primarily composed of phospholipids) coated with prostate membrane specific antigen specific antibodies. We prepared curcumin-loaded liposomes of various lipid compositions by sonication at an average size of 100-150 nm. Un-entrapped curcumin was removed by size exclusion chromatography. Data show that curcumin preferentially partitioned into liposomes prepared from dimyristoyl phosphatidyl choline (DMPC) and cholesterol among the various compositions tested. The anti-proliferative activity of liposomal curcumin was studied using two human prostate cancer cell lines (LNCaP and C4-2B) by a tetrazolium dye-based (MTT) assay. Treatment of cells with liposomal curcumin (5-10 microM) for 24-48 h at 37 degrees C resulted in at least 70-80% inhibition of cellular proliferation without affecting their viability. On the other hand, free curcumin exhibited similar inhibition only at 10-fold higher doses (>50 microM). We also observed that LNCaP cells were relatively more sensitive to liposomal curcumin mediated block of cellular proliferation than C4-2B cells. We are currently developing liposome formulations with targeting ability to further improve the efficacy of curcumin in vivo.
174 citations
TL;DR: It is concluded that this meta-analysis gave a consistent pattern of an association between mobile phone use and ipsilateral glioma and acoustic neuroma using > or =10-years latency period.
Abstract: We evaluated long-term use of mobile phones and the risk for brain tumours in case-control studies published so far on this issue. We identified ten studies on glioma and meta-analysis yielded OR = 0.9, 95% CI = 0.8-1.1. Latency period of > or =10-years gave OR = 1.2, 95% CI = 0.8-1.9 based on six studies, for ipsilateral use (same side as tumour) OR = 2.0, 95% CI = 1.2-3.4 (four studies), but contralateral use did not increase the risk significantly, OR = 1.1, 95% CI = 0.6-2.0. Meta-analysis of nine studies on acoustic neuroma gave OR = 0.9, 95% CI = 0.7-1.1 increasing to OR = 1.3, 95% CI = 0.6-2.8 using > or =10-years latency period (four studies). Ipsilateral use gave OR = 2.4, 95% CI = 1.1-5.3 and contra-lateral OR = 1.2, 95% CI = 0.7-2.2 in the > or =10-years latency period group (three studies). Seven studies gave results for meningioma yielding overall OR = 0.8, 95% CI = 0.7-0.99. Using > or =10-years latency period OR = 1.3, 95% CI = 0.9-1.8 was calculated (four studies) increasing to OR = 1.7, 95% CI = 0.99-3.1 for ipsilateral use and OR = 1.0, 95% CI = 0.3-3.1 for contralateral use (two studies). We conclude that this meta-analysis gave a consistent pattern of an association between mobile phone use and ipsilateral glioma and acoustic neuroma using > or =10-years latency period.
159 citations
TL;DR: Results demonstrate that an ellagitannin-rich pomegranate extract can inhibit tumor-associated angiogenesis as one of several potential mechanisms for slowing the growth of prostate cancer in chemopreventive applications.
Abstract: Angiogenesis is critical to tumor growth and is stimulated by tissue hypoxia due to poor oxygen delivery. In turn, cellular hypoxia leads to angiogenesis via the induction of hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) at a cellular level. Pomegranate juice and extracts, which are rich sources of ellagitannins, have been shown to have chemopreventive potential against prostate cancer, but there have been no studies on the effects of an ellagitannin-rich pomegranate extract on angiogenesis. Human prostate cancer cells (LNCaP) and human umbilical vein endothelial cells (HUVEC) were incubated with a pomegranate extract standardized to ellagitannin content (POMx), under normoxic and hypoxic conditions in vitro. Human prostate cancer cells (LAPC4) were injected subcutaneously into severe combined immunodeficient (SCID) mice and the effects of oral administration of POMx on tumor growth, microvessel density, and HIF-1alpha and VEGF expression were determined after 4 weeks of treatment. POMx inhibited the proliferation of LNCaP and HUVEC cells significantly under both normoxic and hypoxic conditions. HIF-1alpha and VEGF protein levels were also reduced by POMx under hypoxic conditions. POMx decreased prostate cancer xenograft size, tumor vessel density, VEGF peptide levels and HIF-1alpha expression after 4 weeks of treatment in SCID mice. These results demonstrate that an ellagitannin-rich pomegranate extract can inhibit tumor-associated angiogenesis as one of several potential mechanisms for slowing the growth of prostate cancer in chemopreventive applications. Further studies in humans are needed to confirm that angiogenesis can be inhibited by an ellagitannin-rich pomegranate extract administered orally as a dietary supplement.
129 citations
TL;DR: This study found that, following the same protocol of colorectal cancer induction, GF rats developed less and smaller tumors than CV rats, and the GF rats that did not develop cancer also presented a better anticancer immune response with an increase in NK, NKT, CTL, B cells and cytotoxicity in peripheral blood.
Abstract: Intestinal microbiota are considered to play an important role both in colorectal tumor development and in the modulation of mucosal immunity. Studies on animals reared in germ-free (GF, without intestinal microbiota) versus conventional (CV, with regular microbiota colonization of the bowel) conditions can aid in clarifying the influence of bacteria on carcinogenesis and the anticancer immune response. The capability of the intestinal environment to modulate anticancer immunity not only at the mucosal but also at the systemic level is still an open question. In our study we found that, following the same protocol of colorectal cancer induction, GF rats developed less and smaller tumors than CV rats. The GF rats that did not develop cancer also presented a better anticancer immune response with an increase in NK, NKT, CTL, B cells and cytotoxicity in peripheral blood. We hypothesize that the lower antigenic challenge and the absence of the 'physiological inflammation', caused by the commensal microbiota in the gut of CV rats, may enhance the capability of the GF rats to develop more efficacious anti-cancer immune responses. The different levels of tolerance/ regulatory mechanisms in GF versus the CV animals may modulate the anticancer response not only at the mucosal but also at the systemic immunity level.
127 citations
TL;DR: The results suggest that PIK3CA mutations in HNSCC are likely to be oncogenic and may significantly contribute to H NSCC carcinogenesis and pave attractive target for therapeutic prevention.
Abstract: Phosphatidylinositol 3-kinases (PI3Ks) are heterodimeric lipid kinases that regulate cellular activities such as proliferation, survival, motility and morphology. Recent studies reported that the p110alpha (PIK3CA), catalytic subunit of PI3-kinase is somatically mutated in human cancers. Hot- spot mutations (E542K, E545K and H1047R) are reported to have higher oncogenic potential. Although PIK3CA mutations were reported in head and neck squamous cell carcinomas (HNSCC) of limited ethnicity, the functional consequences of HNSCC-associated PIK3CA mutations have not been examined. Status of PI3K signaling related genes (PTEN-RAS-EGFR) in the presence of PIK3CA mutation have not been reported. In this study, we analyzed exons 9 and 20 of PIK3CA in 54 samples, including 17 HNSCC cell lines, 19 Indian and 18 Vietnamese primary tumors. We found mutations in 29.4% (5/17) of HNSCC cell lines, 10.5% (2/19) of Indian tumors and no mutation (0/18) in Vietnamese tumors. Two homozygous PIK3CA mutations were found in cell lines and a novel insertion mutation with oncogenicity in Indian tumor. Analysis of PI3K signaling related genes showed that PIK3CA and PTEN mutations were mutually exclusive, though PTEN mutation is uncommon in HNSCC. However, PIK3CA mutation coexisted with H-RAS mutation. Furthermore, PIK3CA mutations were mutually exclusive to EGFR amplification. All the 5 mutants that we found in HNSCC, showed increased PI3 kinase activities, followed by growth factor independent higher colony forming efficiency, changes in morphology, higher rates of migration and invasion compared with PIK3CA wild-type. Our study is the first to examine the oncogenic potential of PIK3CA mutants associated with HNSCC and report on PIK3CA mutations in Indian and Vietnamese ethnicity. These results suggest that PIK3CA mutations in HNSCC are likely to be oncogenic and may significantly contribute to HNSCC carcinogenesis and pave attractive target for therapeutic prevention.
124 citations
TL;DR: It is suggested that trastuzumab combined with chemotherapeutic agents can be active against gastric cancer with HER2 amplification, and the mechanism of the growth inhibition is elucidated.
Abstract: HER2 has been found to be amplified in 10-20% of gastric cancers, and is correlated with poor outcome. The aims of this study were to recognize HER2 amplification in gastric cancer cell lines via fluorescence in situ hybridization and to evaluate the growth inhibitory effect of trastuzumab in HER2-amplified cell lines. To elucidate the mechanism of the growth inhibition, we performed cell cycle analysis and immunoblotting of downstream molecules. We also conducted drug interaction studies of trastuzumab with other chemotherapeutic agents. HER2 amplification was newly identified only in SNU-216 cells, and trastuzumab moderately inhibited the growth of SNU-216 cells and positive controls. Trastuzumab-mediated G1 arrest occurred with increased expression of p27(KIP1) and decreased cyclins. Phosphorylation of HER2 and downstream molecules, STAT3, AKT, and ERK, was also inhibited by trastuzumab. Treatment of SNU-216 cells with trastuzumab plus cisplatin resulted in a synergistic inhibitory effect, whereas treatment of SNU-216 cells with trastuzumab plus 5-FU, or trastuzumab plus oxaliplatin produced an additive effect. These results suggest that trastuzumab combined with chemotherapeutic agents can be active against gastric cancer with HER2 amplification.
122 citations
TL;DR: This study provides new scientific data on TO and suggests that TO extracts or individual components present in the extracts may be of value as novel anti-cancer agents.
Abstract: Ethnotraditional use of plant-derived natural products plays a significant role in the discovery and development of potential medicinal agents. Plants of the genus Taraxacum, commonly known as dandelions, have a history of use in Chinese, Arabian and Native American traditional medicine, to treat a variety of diseases including cancer. To date, however, very few studies have been reported on the anti-carcinogenic activity of Taraxacum officinale (TO). In the present study, three aqueous extracts were prepared from the mature leaves, flowers and roots, and investigated on tumor progression related processes such as proliferation and invasion. Our results show that the crude extract of dandelion leaf (DLE) decreased the growth of MCF-7/AZ breast cancer cells in an ERK-dependent manner, whereas the aqueous extracts of dandelion flower (DFE) and root (DRE) had no effect on the growth of either cell line. Furthermore, DRE was found to block invasion of MCF-7/AZ breast cancer cells while DLE blocked the invasion of LNCaP prostate cancer cells, into collagen type I. Inhibition of invasion was further evidenced by decreased phosphorylation levels of FAK and src as well as reduced activities of matrix metalloproteinases, MMP-2 and MMP-9. This study provides new scientific data on TO and suggests that TO extracts or individual components present in the extracts may be of value as novel anti-cancer agents.
111 citations
TL;DR: Simulations produce three distinct stages of carcinogenesis that are consistent with the initiation, promotion, and progression stages observed experimentally and provide insight into the underlying cellular and microenvironmental dynamics that govern these empirical observations.
Abstract: Human carcinogenesis is a multistep process in which epithelial cells progress through a series of premalignant phenotypes until an invasive cancer emerges. Extensive experimental observations in carcinogenesis have demonstrated this process can be divided into three general eras: initiation, promotion, and progression. However, this empirically derived, tissue-level explanation of carcinogenesis has not been reconciled with the step-wise genotypic and phenotypic changes encompassed in evolutionary paradigms such as the Feoron-Vogelstein diagram. Here, we analyze an evolutionary model of cellular dynamics that defines mutual interactions of cellular and subcellular events and tissue level changes in tumor growth and morphology. Results are expressed using an adaptive landscape that illustrates the evolutionary potential of cells that allow them to adapt to specific microenvironmental selection forces. It is shown that normal epithelial cells have a novel adaptive landscape that permits coexistence of normal cellular populations but also allows invasion by mutant phenotypes. Subsequent cancer evolution is possible due to a relaxation of tissue growth constraints (as mediated by cell-cell and cell-extracellular matrix interactions) and adaptations in response to perturbations in microenvironmental substrate concentrations (due to separation of evolving tumor cells from their blood supply by an intact basement membrane). Simulations, based on the dynamic model, produce three distinct stages of carcinogenesis that are consistent with the initiation, promotion, and progression stages observed experimentally. The simulations provide insight into the underlying cellular and microenvironmental dynamics that govern these empirical observations and suggest novel prevention strategies that may be tested experimentally.
TL;DR: Evidence is provided suggesting that this cytokine, within the tumour microenvironment, could promote HLA-E translocation to the surface of tumour epithelial cells and suggest that this molecule renders tumours less susceptible to immune attack.
Abstract: HLA-E is a non-classical MHC molecule whose expression by tumour cells has been recently reported in several human cancer types. We studied HLA-E expression in colorectal cancer patients, its clinical significance and prognostic value, as well as characterized its expression in colorectal cancer cell lines. We analysed HLA-E expression at the transcript level by qRT-PCR in micro-dissected samples and at the protein level by semiquantitative immunohistochemistry on paraffin-embedded tissue sections from 42 biopsies of colorectal cancer patients. We observed that HLA-E transcript and protein are spontaneously overexpressed in a significant proportion of colorectal tumour biopsies, as compared to normal mucosae. We also found a negative correlation between HLA-E expression and the CD57+ cells infiltrate. Moreover, we analysed HLA-E expression in several colorectal cancer cell lines and demonstrated that IFN-gamma upregulates the expression of membrane HLA-E in vitro. Interestingly, we demonstrated that colorectal cancer cell lines overexpressing HLA-E at the cell surface inhibited NK-mediated cell lysis. Although IFN-gamma regulatory role needs further investigation, we provide evidence suggesting that this cytokine, within the tumour microenvironment, could promote HLA-E translocation to the surface of tumour epithelial cells. Furthermore, we showed that upregulation of HLA-E could be a marker of shorter disease-free survival in Dukes' C patients and we suggest that this molecule renders tumours less susceptible to immune attack.
TL;DR: The findings surprisingly suggest that D-allose, a simple monosaccharide, may act as a novel anticancer agent via unique TXNIP induction and p27kip1 protein stabilization.
Abstract: 'Rare sugars' are defined as monosaccharides that exist in nature but are only present in limited quantities. The development of mass production method of rare sugars revealed some interesting physiological effects of these on animal cells, but the mechanisms have not been well studied. We examined the effect of D-allose on the proliferation of cancer cells and the underlying molecular mechanism of the action. The HuH-7 hepatocellular carcinoma cells were treated with various monosaccharides for 48 h and D-allose was shown to inhibit cell growth by 40% in a dose-dependent manner. D-allose induced G1 cell cycle arrest but not apoptosis. The microarray analysis revealed that D-allose significantly up-regulated thioredoxin interacting protein (TXNIP) gene expression, which is often suppressed in tumor cells and western blot analysis confirmed its increase at protein level. The overexpression of TXNIP also induced G1 cell cycle arrest. Analysis of cell cycle regulatory genes showed p27kip1, a key regulator of G1/S cell cycle transition, to be increased at the protein but not the transcriptional level. Protein interaction between TXNIP and jab1, and p27kip1 and jab1, was observed, suggesting stabilization of p27kip1 protein by the competitive inhibition of jab1-mediated nuclear export of p27kip1 by TXNIP. In addition, increased interaction and nuclear localization of TXNIP and p27kip1 were apparent after D-allose treatment. Our findings surprisingly suggest that D-allose, a simple monosaccharide, may act as a novel anticancer agent via unique TXNIP induction and p27kip1 protein stabilization.
TL;DR: Cdc42 was found to be overexpressed with high incidence in colorectal cancer samples, and this expression was associated with silencing of ID4 with statistical significance (p<0.05), suggesting that Cdc42 may have a role in the development of colon cancer.
Abstract: Cdc42, a member of Rho GTPases family, is involved in the regulation of several cellular functions, such as rearrangement of actin cytoskeleton, membrane trafficking, cell-cycle progression, and transcriptional regulation. Aberrant expression or activity of Cdc42 has been reported in several tumours. Here, the specific role of Cdc42 in development and progression of colorectal cancer was analyzed through microarrays technology. A comparative analysis of Cdc42 overexpressing cells versus cells with decreased Cdc42 levels through siRNA revealed that Cdc42 overexpression down-regulated the potential tumour suppressor gene ID4. Results were validated by quantitative RT-PCR and the methylation status of the specific promoter, analyzed. Methylation-specific PCR and bisulfite sequencing PCR analysis revealed that Cdc42 induced the methylation of the CpG island of the ID4 promoter. Colorectal adenocarcinoma samples were compared with the corresponding adjacent normal tissue of the same patient in order to determine specific gene expression levels. The downregulation of ID4 by Cdc42 was also found of relevance in colorectal adenocarcinoma biopsies. Cdc42 was found to be overexpressed with high incidence (60%) in colorectal cancer samples, and this expression was associated with silencing of ID4 with statistical significance (p<0.05). Cdc42 may have a role in the development of colon cancer. Furthermore, inhibition of Cdc42 activity may have a direct impact in the management of colorectal cancer.
TL;DR: Overexpression of MMP-1 in prostate cancer cells increases cell invasion and migration as measured by modified transwell assays and treatment of mice with an M MP-1 specific inhibitor significantly decreased prostate tumor growth and incidence of lung metastasis in vivo.
Abstract: Cell migration and invasion are critical events during the progression to metastasis. Matrix metalloproteinase-1 (MMP-1) is involved in the progression of human malignancies, but the precise role of MMP-1 in tumor invasion and metastasis remains unclear. In the present study, we investigated the role of MMP-1 in tumor cell invasion and metastasis by overexpressing MMP-1 in prostate cancer cells. Overexpression of MMP-1 in prostate cancer cells increases cell invasion and migration as measured by modified transwell assays. Furthermore, the results from a bioluminescence tumor/metastasis model showed that the overexpression of MMP-1 significantly induces prostate tumor growth and the incidence of lung metastasis. We observed that this increase in tumor growth correlates with an increase in tumor angiogenesis. In addition, we assessed the importance of MMP-1 expression in cell invasion and migration by inhibiting MMP-1 activity with specific inhibitor and antibodies. Blockade of MMP-1 activity inhibited prostate cancer cell migration and invasion in vitro. Treatment of mice with an MMP-1 specific inhibitor significantly decreased prostate tumor growth and incidence of lung metastasis in vivo. Collectively, our findings suggest that MMP-1 plays an important role in prostate cancer progression during the invasive and metastatic stages of the disease.
TL;DR: Examination of published data regarding the contribution of genetic polymorphisms to risk of head and neck cancer found increased risk for HNC was associated consistently with the ALDH2*1/*2, p53 codon 72 Pro/Pro and EPHX1 codon 113 Tyr/His and His/His genotypes.
Abstract: The aim of this report is to review and evaluate, in a comprehensive manner, the published data regarding the contribution of genetic polymorphisms to risk of head and neck cancer (HNC). All relevant studies available in MEDLINE and published before July 2007 were identified. Studies carried out in humans that compared HNC patients with at least 1 standard control group were considered for analysis. Two hundred and eighteen publications and 3 published meta-analyses were identified. Seventy-five (34%) studies were conducted in Asian, 72 (33%) in American, and 68 (31%) in European countries. The most widely studied gene was GSTM1 (58 studies), followed by GSTT1 (42 studies), GSTP1 (codon 105, 22 studies) and p53 (codon 72, 20 studies). GSTM1, GSTT1, GSTP1, XRCC1 codons 194 and 399, and CYP1A1 codon 462 were examined by meta-analyses, and significant relations were found between the GSTM1-null genotype and an increased risk for HNC. In addition, increased risk for HNC was associated consistently with the ALDH2*1/*2, p53 codon 72 Pro/Pro and EPHX1 codon 113 Tyr/His and His/His genotypes. Cohort studies that simultaneously consider multiple genetic and environmental factors possibly involved in carcinogenesis of the head and neck are needed to ascertain not only the relative contribution of these factors to tumor development but also the contributions of their putative interactions.
TL;DR: The results suggest that cadherin-11 promotes homing and migration to bone and osteoclastogenesis through mediating the homophilic interactions of breast cancer cells with marrow stromal/osteoblastic cells, thereby enhancing bone metastases.
Abstract: Cell adhesion molecules have been implicated in the selective colonization of cancer in distant organs. Breast cancer has a strong predilection for spreading to bone. Cadherin-11, which is one of the classical type-2 cadherin family members and mediates homophilic cell-cell adhesion, is constitutively expressed in stromal and osteoblastic cells in bone marrow. Elevated cadherin-11 expression is also found in aggressive human breast cancers. Here, we investigated the role of the interactions between breast cancer cells and bone marrow stromal/osteoblastic cells via cadherin-11 in the selective spread to bone. The bone-seeking clone of the MDA-MB-231 human breast cancer cells showed greater cadherin-11 expression than the parental and the brain-seeking clone. Cadherin-11 overexpression in MDA-MB-231 cells increased bone metastases with promoted bone resorption, while the natural variant form of cadherin-11 that is unable to establish cell-cell adhesion did not. Of note, introduction of cadherin-11 showed no effects on lung metastases. Fluorescence-activated cell sorter analysis using the fluorescent dye-labeled cancer cells showed that early colonization in bone marrow was increased by cadherin-11. Co-cultures with the MC3T3-E1 osteoblastic cells that constitutively expressed cadherin-11 caused an up-regulation of parathyroid hormone-related protein (PTH-rP) production in MDA-MB-231 cells overexpressing cadherin-11. The conditioned medium of the co-cultures increased osteoclastogenesis, which was blocked by a neutralizing antibody to PTH-rP. In conclusion, our results suggest that cadherin-11 promotes homing and migration to bone and osteoclasto-genesis through mediating the homophilic interactions of breast cancer cells with marrow stromal/osteoblastic cells, thereby enhancing bone metastases.
TL;DR: The findings should expand the understanding of the molecular framework of American ginseng as an anti-cancer agent and elucidate the mechanisms of action.
Abstract: American ginseng (Panax quinquefolius L., Araliaceae) possesses anti-cancer potential and is one of the most commonly used herbal medicines in the United States. Ginsenoside Rg3, one of the saponins in American ginseng, has been shown to inhibit tumor growth. In this study, we sought to characterize the downstream genes targeted by American ginseng extracts in HCT-116 human colorectal cancer cells. We first demonstrated that the content of Rg3 in American ginseng steamed at 120 degrees C for 2 h (referred to as S2h) was significantly increased when compared with that of the unsteamed ginseng. Both S2h and Rg3 exhibited antiproliferative effects on HCT-116 cells. Using the Affymetrix high density genechips containing more than 40,000 genes and ESTs, the gene expression profiling of HCT-116 cells were assayed. Microarray data indicated that the expression levels of 76 genes were changed significantly after treatment with S2h or Rg3, whereby it was found that 52 of the 76 genes were up-regulated while the remaining 24 were down-regulated. Ingenuity pathways analysis of top functions affected by both S2h and Rg3 were carried out. The most effected pathway is the Ephrin receptor pathway. To validate the microarray data, quantitative real-time PCR of six candidate target genes was conducted, whereby it was found that three genes were up-regulated (AKAPA8L, PMPCB and PDE5A) and three were down-regulated (PITPNA, DUS2L and RIC8A). Although further studies are needed to elucidate the mechanisms of action, our findings should expand the understanding of the molecular framework of American ginseng as an anti-cancer agent.
TL;DR: It is demonstrated that WT1-shRNA targeting exon 5 should serve as a potent anti-cancer agent for various types of solid tumors.
Abstract: Wilms' tumor gene WT1 is overexpressed in leukemia and various types of solid tumors and plays an important role in leukemogenesis and tumorigenesis. We tested apoptosis-inducing ability of short hairpin RNAs targeting exon 5 (shWTE5), exon10 (shWTE10) and 3'UTR (shWT3U) of the WT1 gene. Among the three WT1-shRNAs, since shWTE5 most effectively induced apoptosis, its ability as an apoptosis-inducing agent was intensively examined. shWTE5 induced mitochondrial damage and resultant apoptosis in five WT1-expressing solid cancer cells originated from gastric (AZ-521), lung (LU99B), ovarian (TYKnuCPr) cancers, fibrosarcoma (HT-1080) and glioblastoma (A172). Moreover, shWTE5 significantly enhanced apoptosis induced by chemotherapeutic agents, doxorubicin (DOX) and etoposide (ETP), or by death ligand TRAIL in all of the four solid tumor cells examined (HT-1080, LU99B, TYK and A172). Transduction of one each of WT1 isoforms with exon 5 [17AA(+)KTS(+) and 17AA(+)KTS(-)] prevented mitochondrial damage induced by ETP or TRAIL and inhibited apoptosis. These results showed that shWTE5 induced apoptosis through the suppression of the WT1 isoform with exon 5. Furthermore, shWTE5 increased expression of proapoptotic Bak and Bax proteins and decreased antiapoptotic Bcl-xL and Bcl-2 proteins in WT1-expressing HT-1080 cells, indicating that WT1 isoforms with exon 5 might play an antiapoptotic role through regulation of Bcl-2 family genes in solid tumor cells. The results presented here demonstrated that WT1-shRNA targeting exon 5 should serve as a potent anti-cancer agent for various types of solid tumors.
TL;DR: Preliminary in vivo data suggest that it may be possible to generate novel hemi-synthetic derivatives of balanitin-6 and -7 with potentially improved in vitro and in vivo anti-cancer activity and reduced in vivo toxicity, thus markedly improving the therapeutic ratio.
Abstract: Balanites aegyptiaca is a widely distributed African plant of medicinal interest containing a number of cytotoxic and cytostatic compounds. The studies reported here have attempted to further characterize the anti-cancer activity of a mixture of steroidal saponins: balanitin-6 (28%) and balanitin-7 (72%) isolated from Balanites aegyptiaca kernels. The balanitin-6 and -7 mixture (henceforth referred to as bal6/7) has demonstrated appreciable anti-cancer effects in human cancer cell lines in vitro. Bal6/7 displayed higher anti-proliferative activity than etoposide and oxaliplatin, although the mixture was appreciably less active than SN38 and markedly less active than taxol. Bal6/7 demonstrated highest activity against A549 non-small cell lung cancer (NSCLC) (IC(50), 0.3 microM) and U373 glioblastoma (IC(50), 0.5 microM) cell lines. The current study has further indicated that bal6/7 is more a cytotoxic compound than a cytostatic one. However, Bal6/7 does not appear to mediate its anti-proliferative effects by inducing apoptotic cell death. Computer-assisted cellular imaging has revealed that bal6/7 does not induce detergent-like effects in A549 NSCLC and U373 glioblastoma unlike certain saponins. Furthermore there is indication that its in vitro anti-cancer activities result at least partly from depletion of [ATP]i, leading in turn to major disorganization of actin cytoskeleton, ultimately resulting in the impairment of cancer cell proliferation and migration. In contrast to a number of natural products acting as anti-cancer agents, bal6/7 does not induce an increase in intra-cellular reactive oxygen species. In vivo, bal6/7 increased the survival time of mice bearing murine L1210 leukemia grafts to the same extent reported for vincristine. These preliminary in vivo data suggest that it may be possible to generate novel hemi-synthetic derivatives of balanitin-6 and -7 with potentially improved in vitro and in vivo anti-cancer activity and reduced in vivo toxicity, thus markedly improving the therapeutic ratio.
TL;DR: The subcellular localization of HuR is deregulated in a subset of prostate carcinomas, and that this deregulation is linked to an altered expression of the tumorigenic COX-2 protein as well as to an adverse patient prognosis.
Abstract: The human ELAV-like protein HuR is involved in the stabilization of the mRNAs of a group of genes implicated in the regulation of cellular growth, angiogenesis and rapid inflammatory response. HuR is a nuclear shuttling protein, translocating bound mRNAs from the nucleus to the cytoplasm. We have previously observed an increased expression of cyclooxygenase-2 (COX-2) in prostate cancer while cell culture studies have shown that HuR stabilizes the mRNA of COX-2. Based on these mechanistic data, we aimed to investigate the role of HuR in prostate cancer by a tissue-based analysis combined with functional evaluation using a cell culture approach. Investigating 104 primary prostate carcinomas by immunohistochemistry, we found HuR expression to be shifted from a nuclear staining in normal prostate glands to a cytoplasmic staining in carcinoma tissue (p<0.0001). Cytoplasmic HuR expression was significantly correlated with COX-2 expression (p=0.005). Loss of nuclear HuR expression was an indicator of earlier PSA-relapse both in univariate (p=0.04) and multivariate survival analysis (p=0.04). HuR inhibition by Leptomycin B reduced the inducibility of COX-2 in PC-3 prostate cancer cells. We found that the subcellular localization of HuR is deregulated in a subset of prostate carcinomas, and that this deregulation is linked to an altered expression of the tumorigenic COX-2 protein as well as to an adverse patient prognosis. Our results point to a potential prognostic role of HuR expression in prostate cancer diagnostics and propose HuR as a future therapeutic target in prostate cancer therapy.
TL;DR: It is demonstrated that VEGF acts as a survival factor not only for endothelial cells as previously thought, but also for some breast tumour cells, protecting them from apoptosis, particularly under hypoxic stress.
Abstract: Vascular endothelial growth factor (VEGF) is produced by most tumour types and stimulates the growth of new blood vessels in the tumour. The expansion of a solid tumour ultimately leads to the development of hypoxic regions, which increases VEGF production and further angiogenesis. In this study, we examined the role of VEGF in the survival of breast tumour cells under hypoxia. Murine 4T1 and human MDA-MB-231 tumour cells were cultured under normoxic and hypoxic growth conditions in the presence or absence of VEGF neutralising antibodies. Apoptosis was assessed in addition to changes in expression of the anti- and pro-apoptotic proteins, Bcl-2 and Bad, respectively. The effect of hypoxia on the novel VEGF receptor, NP1 (neuropilin-1) and the role of the PI3K (phosphatidylinositol-3-kinase) signalling pathway in response to VEGF were examined. VEGF blockade resulted in direct tumour cell apoptosis of both tumour cell lines under normoxia and hypoxia. While blocking VEGF resulted in a downregulation of hypoxia-induced Bcl-2 expression, there was a significant increase in the pro-apoptotic protein Bad relative to cells cultured under hypoxia alone. Both hypoxia and VEGF phosphorylated Akt. Neutralising antibodies to VEGF abrogated this effect, implicating the PI3K pathway in VEGF-mediated cell survival of mammary adenocarcinoma cells. This study demonstrates that VEGF acts as a survival factor not only for endothelial cells as previously thought, but also for some breast tumour cells, protecting them from apoptosis, particularly under hypoxic stress. The data presented provide an additional rationale for combining anti-VEGF strategies with conventional anti-cancer therapies such as chemotherapy and radiotherapy.
TL;DR: Results indicate that RFA application can exert an activating effect on the immune system in metastatic cancer patients, favouring trafficking of lymphocyte subsets and enhancing tumor antigen specific cellular immune responses.
Abstract: Radiofrequency tumor ablation (RFA) is a therapeutic modality for liver cancer patients inducing localized tumor necrosis with maximal preservation of normal liver parenchyma. We investigated the immunomodulatory effects exerted by RFA treatment in liver cancer patients with metastatic liver lesions (13 patients) or hepatocellular carcinoma (HCC) (4 patients). Analysis of lymphocyte subsets by flow cytometry revealed that after RFA, CD3+ T cells, in particular CD4+, were decreased in metastatic cancer patients, while no change was observed in HCC patients. Moreover, RFA induced trafficking of naive and memory CD62L+ T cells from circulation to tissues. When characterizing the function of T cells, proliferative response to PHA was strongly increased after 48 h from RFA in metastatic cancer patients. Furthermore, T cells produced IFN-gamma in response to the tumor associated MUC1 antigen. In contrast, humoral immune responses against tumor antigens such as MUC1 and HCV proteins were unaffected by RFA treatment, although increase of circulating B cells was observed only in metastatic cancer patients. These results indicate that RFA application can exert an activating effect on the immune system in metastatic cancer patients, favouring trafficking of lymphocyte subsets and enhancing tumor antigen specific cellular immune responses.
TL;DR: The results suggested that RHAMM expression may be correlated with tumor aggressiveness and offer clues to the development of new treatments for human OSCCs.
Abstract: To characterize cancer-related gene expression changes in oral squamous cell carcinomas (OSCCs), we compared the gene expression profiles in OSCC-derived cell lines with human normal oral keratinocytes (HNOKs). Microarray analysis identified 166 genes that were up-regulated in OSCC-derived cell lines. Gene ontology analysis showed that cancer-related function had the highest significance. Among the genes mapped to the cancer-related network with the highest significance, the receptor for hyaluronan-mediated motility (RHAMM) was evaluated further for mRNA and protein expression in the OSCC cell lines, primary OSCCs. Overexpression of RHAMM protein was observed in all cell lines compared to HNOKs. Immunohistochemical analysis showed highly expressed RHAMM in primary OSCCs, whereas most corresponding normal tissues had no or significant down-regulation of protein immunoreactivity. Real-time quantitative reverse transcriptase-polymerase chain reaction data agreed with the protein expression. Moreover, the RHAMM expression status was correlated with the TNM stage (P<0.001). The results suggested that RHAMM expression may be correlated with tumor aggressiveness and offer clues to the development of new treatments for human OSCCs.
TL;DR: Stable transfectants of pCD lacking its AP and with various mutations in the 27-44 amino acid region of AP, failed to show enhanced cell proliferation or invasion in vitro and tumor growth in vivo, establishing the importance of AP region.
Abstract: Expression and secretion of procathepsin D (pCD) increases proliferation, metastasis and progression of breast cancer but the structural moiety by which pCD exerts these effects is still ambiguous. Here, we present data on a series of pCD stable mutants to identify the pCD region that mediates this mitogenic effect. Mutations affecting the region of the activation peptide (AP) were studied together with catalytic and glycosylation mutants. Mitogenic effect was evaluated using in vitro invasion and proliferation assays and in vivo by determining the tumorigenic potential. The catalytic mutants and glycosylation mutants of pCD continued to display enhanced cell proliferation, invasion and tumorigenicity similar to stable transfectants of native pCD, suggesting that neither the proteolytic activity nor the sugar moieties contribute to the mitogenic effect. However, stable transfectants of pCD lacking its AP and with various mutations in the 27-44 amino acid region of AP, failed to show enhanced cell proliferation or invasion in vitro and tumor growth in vivo, establishing the importance of AP region. Our study concludes that the entire 27-44 amino acid region of AP is necessary for the stimulatory actions of pCD on breast cancer cells.
TL;DR: The results suggest that C-FABP may be used as a potential prognostic marker to predict patient outcome and the increased C-fABP expression is a possible target to inhibit the malignant progression of prostate cancer cells.
Abstract: C-FABP or E-FABP is a metastasis inducing gene over expressed in human prostate carcinomas. To study its prognostic significance, an archival set of prostate tissues was analysed immunohistochemically. Levels of both nuclear and cytoplasmic C-FABP expression in carcinoma cells were significantly higher than those in normal and BPH tissues and the increased C-FABP was significantly associated with a reduced patient survival time. To test the therapeutic potential of targeting C-FABP, a clone (Si-clone-2) of cells was established by interfering C-FABP expression in highly malignant PC-3M cells. Suppression of C-FABP in cancer cells significantly inhibited their proliferation and tumourigenicity in vitro. When Si-clone-2 cells were orthotopically implanted into the prostate gland of mouse, 2/13 mice produced primary tumours with an average size of 23+/-5 mg, and no metastasis was produced in any of the 13 animals. Whereas in the control group, all 14 mice produced primary tumours with an average size of 1450+/-370 mg and 9/14 (64.3%) produced metastasis. When inoculated subcutaneously, all 5 mice inoculated with control cells developed tumours from day 4, with an average size of 1471+/-544 mm(3) at 5 weeks after the inoculation; whereas Si-clone-2 cells produced no tumours in any of the 5 animals at any time-point, indicating the suppression occurred at the initiation stage. Our results suggest that C-FABP may be used as a potential prognostic marker to predict patient outcome and the increased C-FABP expression is a possible target to inhibit the malignant progression of prostate cancer cells.
TL;DR: Results indicate that the loss of WT periostin by down-regulation and/or alternative splicing, which produces Variant I, is closely correlated with the development of bladder cancer.
Abstract: We have previously reported that the expression of periostin mRNA is significantly repressed in human bladder cancer tissues, and that periostin plays a role as a suppressive factor for invasion and metastasis in the progression of human bladder cancers. In this study, to clarify the role of alternative splicing of periostin in human bladder carcinogenesis, we examined the expression of wild-type (WT) and spliced variants of periostin mRNA in normal bladder and bladder cancer tissues. Although both WT and spliced periostin mRNA were expressed in all normal bladder tissues examined, no WT periostin mRNA was detected in the examined transitional cell carcinomas (TCCs) of the bladder (0/23) or in bladder cancer cell lines (0/6). Spliced variants of periostin were detected in 48% (11/23) of TCC tissues and 33% (2/6) of bladder cancer cell lines. Two types of spliced periostin (Variants I and II) were successfully isolated from bladder cancer tissues, but Variant I, which is predominantly expressed in bladder cancer tissues, did not show suppressor activity on in vitro invasiveness and in vivo metastasis of cancer cells. Immunohistochemical analysis indicated that strong belt-like expression of periostin protein was observed in the stroma just beneath the normal bladder epithelium, while it was mostly attenuated in bladder cancer tissues. These results indicate that the loss of WT periostin by down-regulation and/or alternative splicing, which produces Variant I, is closely correlated with the development of bladder cancer.
TL;DR: The effectiveness of FTI CH4512600 to suppress tumor growth in vivo and to prolong mouse survival significantly from 36.9+/-2.9 to 50.3+/-9.4 days is demonstrated.
Abstract: To examine the drug efficacy of a novel farnesyltransferase inhibitor (FTI), CH4512600, in vivo, we developed a reliable liver metastasis model of human colon cancer using NOD/Shi-scid IL2Rgamma(null) (NOG) mice. Eleven human colon cancer cell lines were examined for their ability to form diverse metastatic foci in the livers of NOG mice. When inoculated with 10(4) COLO320DM, HCT 116, HT-29, WiDr, LoVo and LS174T cells, liver metastasis was evident in 100% (6/6), 100% (6/6), 88.9% (8/9), 87.5% (7/8), 83.3% (5/6) and 50.0% (3/6) of the NOG mice, respectively. CaCo2, COLO201, LS123, SW48 and SW1417 showed no metastasis when seeded at 10(4) cells even in NOG mice. The mRNA expression levels and genetic mutations of N, H and K-RAS genes, which directly affect the levels of cellular RAS protein that would be molecular target for FTI, were also examined in these six metastatic human colon cancer cell lines for molecular biological and genotypic characteristics. Only three cell lines had a point mutation in the RAS oncogene. LS174T cell line had a point mutation of the K-RAS gene at codon 12 (gly12 --> asp; G12D), and HCT 116 and LoVo cell lines had a point mutation of the K-RAS gene at codon 13 (gly13 --> asp; G13D). Relative gene expression levels of N, H and K-RAS genes in the HCT 116 cell line were 2.6-5.0-fold lower than that of LS174T and LoVo cell lines. We selected HCT 116 cell line from our liver metastasis model for evaluation of FTI CH4512600 efficacy in vivo. Using the NOG mouse liver metastasis model, we demonstrated the effectiveness of FTI CH4512600 to suppress tumor growth in vivo and to prolong mouse survival significantly from 36.9+/-2.9 to 50.3+/-9.4 days.
TL;DR: Results suggest that serum starvation induces G1 arrest through suppression of Skp2-dependent CDK2 activity and Skp 2-independent CDK4 activity in human SK-OV-3 ovarian cancer cells.
Abstract: Recent studies have suggested that Skp2, an SCF-type ubiquitin ligase, positively regulates cell cycle through degradation of p27, which is an inhibitor of cyclin-dependent kinase 2 (CDK2), which drives cells from the G1 to S phase of cell cycles. In the present study, we examined key regulatory proteins involved in serum starvation-induced cell cycle arrest in human ovarian cancer cells, SK-OV-3. Cell cycle analysis showed that cells were arrested at the G1 phase after serum starvation. Western blot analysis showed that the protein levels of CDK4 and CDK2 were significantly decreased in SK-OV-3 cells. Consistently, Roscovitine, an inhibitor of CDK2, induced cell cycle arrest in normally proliferating cells and a chemical inhibitor of CDK4, 3-ATA [3-Amino-9-thio(10H)-acridone], was found to induce growth arrest. We also found that the protein level of Skp2 was dramatically decreased in response to serum starvation. Moreover, CDK2 protein, which allows cell cycle transit from the G1 to the S phase, was decreased when the Skp2 expression was inhibited by specific siRNA of Skp2, but CDK4 was not decreased. Therefore, these results suggest that serum starvation induces G1 arrest through suppression of Skp2-dependent CDK2 activity and Skp2-independent CDK4 activity in human SK-OV-3 ovarian cancer cells.
TL;DR: The findings suggest that under hypoxic conditions an autocrine loop between VEGF-C/VEGFR-3 and HIF-1 alpha is possible in breast carcinoma and lung carcinoma but not in colorectal carcinoma cell lines.
Abstract: Adaptation to hypoxia, a universal hallmark of carcinomas, is a critical step for tumor cell survival and growth. One of the principal regulators of hypoxia-responsive pathways is the transcription factor hypoxia-inducible factor-1 alpha (HIF-1 alpha). Currently, it is known that tumoral production of members of the vascular endothelial growth factor (VEGF)-family (VEGFs) may promote tumor growth and progression by acting on carcinoma cells that express the cognate receptors (VEGFRs). However, the influence of hypoxia in the formation of such a tumoral VEGF/VEGFR loop is not completely understood. In the present study we examined the potential existence of a HIF-1 alpha/VEGF/VEGFR autocrine loop on commonly occurring carcinomas. The experiments were performed on five colorectal carcinoma cell lines, one breast (MCF7) and one lung (A549) adenocarcinoma cell line under normoxic and oxygen stress conditions using HIF-1 alpha-EIA, VEGFs-ELISA as well as RT-PCR and immunofluorescence for VEGFRs. HIF-1 alpha overexpression was found already after 2 h of exposure to hypoxia in all above mentioned cell lines, thus documenting that activation of the transcription factor HIF-1 alpha is an early cellular event. Under hypoxic conditions a significant upregulation and activation of HIF-1 alpha accompanied by an increased production of VEGF in MCF7 and A549 was observed. The well-differentiated colorectal carcinoma cell lines were 'hypoxia-resistant' showing unchanged levels of HIF-1 alpha and VEGF under hypoxia. None of the cell lines used in this study expressed the VEGF receptors VEGFR-1 and VEGFR-2 under normoxia and hypoxia. Additionally, all colorectal carcinoma cell lines were negative for VEGFR-3 transcripts in both conditions. However, VEGFR-3 mRNA and protein were expressed and under hypoxia overexpressed in MCF7 and A549. Hypoxic cultures of both cell lines secreted in elevated levels the VEGFR-3 ligand VEGF-C but not VEGF-D. Our findings suggest that under hypoxic conditions an autocrine loop between VEGF-C/VEGFR-3 and HIF-1 alpha is possible in breast carcinoma and lung carcinoma but not in colorectal carcinoma cell lines.