Showing papers in "Cancer Science in 2011"

YN968D1 is a novel and selective inhibitor of vascular endothelial growth factor receptor-2 tyrosine kinase with potent activity in vitro and in vivo

Abstract: Angiogenesis is an important process in cell development, especially in cancer. Vascular endothelial growth factor (VEGF) signaling is an important regulator of angiogenesis. Several therapies that act against VEGF signal transduction have been developed, including YN968D1, which is a potent inhibitor of the VEGF signaling pathway. This study investigated the antitumor activity of YN968D1 (apatinib mesylate) in vitro and in vivo. YN968D1 potently suppressed the kinase activities of VEGFR-2, c-kit and c-src, and inhibited cellular phosphorylation of VEGFR-2, c-kit and PDGFRβ. YN968D1 effectively inhibited proliferation, migration and tube formation of human umbilical vein endothelial cells induced by FBS, and blocked the budding of rat aortic ring. In vivo, YN968D1 alone and in combination with chemotherapeutic agents effectively inhibited the growth of several established human tumor xenograft models with little toxicity. A phase I study of YN968D1 has shown encouraging antitumor activity and a manageable toxicity profile. These findings suggest that YN968D1 has promise as an antitumor drug and might have clinical benefits.

Aminopeptidase N (CD13) as a target for cancer chemotherapy

Abstract: The enzyme aminopeptidase N (APN, also known as CD13) is a Zn2+ dependent membrane-bound ectopeptidase that degrades preferentially proteins and peptides with a N-terminal neutral amino acid. Aminopeptidase N has been associated with the growth of different human cancers and suggested as a suitable target for anti-cancerous therapy. Different approaches have been used to develop new drugs directed to this target, including enzyme inhibitors as well as APN-targeted carrier constructs. This review discusses the prevalence and possible function of APN in malignant diseases, mainly solid tumors, as well as its “drugability” evaluated in preclinical in vivo models, and also provides a brief overview of current clinical trials focused on APN. (Cancer Sci 2011; 102: 501–508)

Association of a novel long non‐coding RNA in 8q24 with prostate cancer susceptibility

Abstract: Recent genome-wide association studies reported strong and reproducible associations of multiple genetic variants in a large "gene-desert" region of chromosome 8q24 with susceptibility to prostate cancer (PC). However, the causative or functional variants of these 8q24 loci and their biological mechanisms associated with PC susceptibility remain unclear and should be investigated. Here, focusing on its most centromeric region (so-called Region 2: Chr8: 128.14-128.28 Mb) among the multiple PC loci on 8q24, we performed fine mapping and re-sequencing of this critical region and identified SNPs (single nucleotide polymorphisms) between rs1456315 and rs7463708 (chr8: 128,173,119-128,173,237 bp) to be most significantly associated with PC susceptibility (P = 2.00 × 10(-24) , OR = 1.74, 95% confidence interval = 1.56-1.93). Importantly, we show that this region was transcribed as a ∼13 kb intron-less long non-coding RNA (ncRNA), termed PRNCR1 (prostate cancer non-coding RNA 1), and PRNCR1 expression was upregulated in some of the PC cells as well as precursor lesion prostatic intraepithelial neoplasia. Knockdown of PRNCR1 by siRNA attenuated the viability of PC cells and the transactivation activity of androgen receptor, which indicates that PRNCR1 could be involved in prostate carcinogenesis possibly through androgen receptor activity. These findings could provide a new insight in understanding the pathogenesis of genetic factors for PC susceptibility and prostate carcinogenesis.

Nanomedicine in cancer therapy: Innovative trends and prospects

Abstract: Cancer is a leading cause of morbidity and mortality worldwide, with recent advancements resulting in modest impacts on patient survival. Nanomedicine represents an innovative field with immense potential for improving cancer treatment, having ushered in several established drug delivery platforms. Nanoconstructs such as liposomes are widely used in clinics, while polymer micelles are in advanced phases of clinical trials in several countries. Currently, the field of nanomedicine is generating a new wave of nanoscale drug delivery strategies, embracing trends that involve the functionalization of these constructs with moieties that enhance site-specific delivery and tailored release. Herein, we discuss several advancements in established nanoparticle technologies such as liposomes, polymer micelles, and dendrimers regarding tumor targeting and controlled release strategies, which are being incorporated into their design with the hope of generating a more robust and efficacious nanotherapeutic modality. We also highlight a novel strategy known as multistage drug delivery; a rationally designed nanocarrier aimed at overcoming numerous biological barriers involved in drug delivery through the decoupling of various tasks that comprise the journey from the moment of systemic administration to arrival at the tumor site.

miR‐92 is a key oncogenic component of the miR‐17–92 cluster in colon cancer

Abstract: MicroRNAs (miRNAs) belong to a class of endogenously expressed non-coding small RNAs that function primarily as gene regulators. Growing evidence suggests that miRNAs play a significant role in tumor development, making them potential biomarkers for cancer diagnosis and prognosis. The miR-17-92 cluster has emerged as an important locus, being highly overexpressed in several cancers in association with cancer development and progression. The miR-17-92 miRNA cluster generates a single polycistronic primary transcript that yields six mature miRNAs: miR-17, miR-18a, miR-19a, miR-20a, miR-19b, and miR-92a. In colon cancer development, the pathophysiologic roles of these transcripts and their targets are largely unknown. In the present study, we performed copy number analyses of the six miRNAs transcribed from the miR-17-92 cluster in colon tumor tissues. We determined that miR-92a was transcribed at higher levels than the other five miRNAs in both adenomas and carcinoma. In addition, miR-92a directly targeted the anti-apoptotic molecule BCL-2-interacting mediator of cell death (BIM) in colon cancer tissues. An anti-miR-92a antagomir induced apoptosis of colon cancer-derived cell lines. These data indicate that miR-92a plays a pivotal role in the development of colorectal carcinoma.

RNA aptamer against a cancer stem cell marker epithelial cell adhesion molecule

Abstract: The lack of a specific targeting strategy against cancer stem cells in current cancer treatment regimens is at least partly responsible for life-threatening cytotoxicity for patients undergoing traditional chemotherapy An effective cancer stem cell targeting system is urgently required for the next generation of cancer medicine Epithelial cell adhesion molecule (EpCAM) is overexpressed in most solid cancers and it has recently been identified as a cancer stem cell marker In this study, we isolated a 40-base RNA aptamer that binds to EpCAM from a random oligonucleotide library using systematic evolution of ligands by exponential enrichment The aptamer was further truncated to 19 bases This 19-nt RNA aptamer interacts specifically with a number of live human cancer cells derived from breast, colorectal, and gastric cancers that express EpCAM, but not with those not expressing EpCAM, as analyzed using flow cytometry and confocal microscopy The binding affinity of the EpCAM RNA aptamer to human cancer cells is approximately 55 nM Importantly, this EpCAM RNA aptamer is efficiently internalized after binding to cell surface EpCAM To our knowledge, this is the first RNA aptamer against a cancer stem cell surface marker being developed Such cancer stem cell aptamers will greatly facilitate the development of novel targeted nanomedicine and molecular imaging agents for cancer theranostics

Macrophage infiltration and its prognostic relevance in clear cell renal cell carcinoma

Abstract: Most malignant tumors evidence infiltration of many macrophages. In this study, we investigated an anti-inflammatory macrophage phenotype (M2) in clear cell renal cell carcinoma (RCC) using CD163 and CD204 as markers. Immunostaining showed a correlation between the number of CD163(+) cells and age, sex, nuclear grade, and TNM classification. High infiltration of CD163(+) cells was significantly associated with poor clinical prognosis in univariate analysis but not in multivariate analysis. We also carried out in vitro studies to examine cell-cell interactions between macrophages and cancer cells. Culture supernatants from RCC cell lines induced polarization of macrophages toward the M2 phenotype. Coculture of macrophages with cancer cells significantly induced activation of signal transducers and activators of transcription-3 (Stat3) in the cancer cells. Direct coculture of RCC cells with macrophages led to stronger activation of Stat3 in the cancer cells than did indirect coculture using Transwell chamber dishes. Because RCC cells expressed membrane-type macrophage colony-stimulating factor (mM-CSF) on the cell surface, we suggested that this mM-CSF plays an important role in direct cell-cell interactions. Stat3 activation in cancer cells that was induced by coculture with macrophages was suppressed by downregulation of the M-CSF receptor (M-CSFR) in macrophages and by an inhibitor of M-CSFR. In conclusion, investigation of CD163(+) tumor-associated macrophages would be useful for assessment of the clinical prognosis of patients with ccRCC. Cell-cell interactions mediated by mM-CSF and M-CSFR binding could contribute to cancer cell activation.

MiR-96 and miR-183 detection in urine serve as potential tumor markers of urothelial carcinoma: correlation with stage and grade, and comparison with urinary cytology

Abstract: A new diagnostic marker for urothelial carcinoma (UC) is needed to avoid painful cystoscopy during the initial diagnosis and follow-up period. However, the current urine markers are useless because of the low sensitivities and specificities for UC detection. MiR-96 and miR-183 were differentially upregulated microRNA in our previous microRNA screening for UC. The expression levels of miR-96 and miR-183 in the urine samples were significantly higher in 100 UC than in healthy controls (miR-96, P=0.0059; and miR-183, P=0.0044). The receiver-operating characteristic curve analyses demonstrated that each microRNA had good sensitivity and specificity for distinguishing UC patients from non-UC patients (miR-96, 71.0% and 89.2%; and miR-183, 74.0% and 77.3%). Our cohort included 78 UC patients who had undergone urinary cytology. MiR-96 was positively detected in 27 of 44 patients who had had a "negative" urinary cytology diagnosis. We combined the miR-96 detection data with the urinary cytology data, and diagnosed 61 of 78 cases as UC; sensitivity rose from 43.6% to 78.2%. We found significant stepwise increases in miR-96 and miR-183 expression with advancing tumor grade (miR-96, P=0.0057; and miR-183, P=0.0036) and pathological stage (miR-96, P=0.0332; and miR-183, P=0.0117). The expression levels of the microRNA were significantly lower in urine collected after surgery (miR-96, P=0.0241; and miR-183, P=0.0045). In conclusion, miR-96 and miR-183 in urine are promising tumor markers for UC. In particular, miR-96 may be a good diagnostic marker in combination with urinary cytology.

Validation of the histone methyltransferase EZH2 as a therapeutic target for various types of human cancer and as a prognostic marker.

Abstract: The emphasis in anticancer drug discovery has always been on finding a drug with great antitumor potential but few side-effects. This can be achieved if the drug is specific for a molecular site found only in tumor cells. Here, we find the enhancer of zeste homolog 2 (EZH2) to be highly overexpressed in lung and other cancers, and show that EZH2 is integral to proliferation in cancer cells. Quantitative real-time PCR analysis revealed higher expression of EZH2 in clinical bladder cancer tissues than in corresponding non-neoplastic tissues (P < 0.0001), and we confirmed that a wide range of cancers also overexpress EZH2, using cDNA microarray analysis. Immunohistochemical analysis showed positive staining for EZH2 in 14 of 29 cases of bladder cancer, 135 of 292 cases of non-small-cell lung cancer (NSCLC), and 214 of 245 cases of colorectal cancer, whereas no significant staining was observed in various normal tissues. We found elevated expression of EZH2 to be associated with poor prognosis for patients with NSCLC (P = 0.0239). In lung and bladder cancer cells overexpressing EZH2, suppression of EZH2 using specific siRNAs inhibited incorporation of BrdU and resulted in significant suppression of cell growth, even though no significant effect was observed in the normal cell strain CCD-18Co, which has undetectable EZH2. Because EZH2 expression was scarcely detectable in all normal tissues we examined, EZH2 shows promise as a tumor-specific therapeutic target. Furthermore, as elevated levels of EZH2 are associated with poor prognosis of patients with NSCLC, its overexpression in resected specimens could prove a useful molecular marker, indicating the necessity for a more extensive follow-up in some lung cancer patients after surgical treatment. (Cancer Sci 2011; 102: 1298–1305)

let-7 and miR-17-92: small-sized major players in lung cancer development.

Abstract: MicroRNA (miRNA)-encoding small non-coding RNA have been recognized as important regulators of a number of biological processes that inhibit the expression of hundreds of genes. Accumulating evidence also indicates the involvement of miRNA alterations in various types of human cancer, including lung cancer, which has long been the leading cause of cancer death in economically well-developed countries, including Japan. We previously found that downregulation of members of the tumor-suppressive let-7 miRNA family and overexpression of the oncogenic miR-17-92 miRNA cluster frequently occur in lung cancers, and molecular insight into how these miRNA alterations may contribute to tumor development has been rapidly accumulating. The present review summarizes recent advances in elucidation of the molecular functions of these miRNA in relation to their roles in the pathogenesis of lung cancer. Given the crucial roles of miRNA alterations, additional studies are expected to provide a better understanding of the underlying molecular mechanisms of disease development, as well as a foundation for novel strategies for cancer diagnosis and treatment of this devastating disease. (Cancer Sci 2011; 102: 9–17)

Cancer detection using infrared hyperspectral imaging.

Abstract: During the last few decades, many studies have been performed on the early detection of cancer using noninvasive or minimally invasive techniques in lieu of traditional excisional biopsy. Early detection can make an immense difference because cancer treatment is often simpler and more effective when diagnosed at an early stage. Cancer detecting methods may help physicians to diagnose cancer, to dissect the malignant region with a safe margin, and to evaluate the tumor bed after resection. In this paper, the advanced hyperspectral imaging system has been assessed using infrared wavelengths region for tumor detection. We were able to identify an appropriate wavelength region for cancer detection, spatially resolved images, and highlight the differences in reflectance properties of cancerous versus non-cancerous tissues. The capability of this instrument was demonstrated by observing gastric tumors in 10 human subjects. The spectral signatures were extracted and evaluated in cancerous and non-cancerous tissues. Processing means with the standard deviation of the spectral diagram, support vector machine, and first derivatives and integral of in spectral diagram were proposed to enhance and detect the cancerous regions. The first derivatives in spectral region between 1226-1251 nm and 1288-1370 nm were proposed as criteria that successfully distinguish between non-cancerous and cancerous tissue. The results of this study will lead to advances in the optical diagnosis of cancer.

Monocarboxylate transporters 1 and 4 are involved in the invasion activity of human lung cancer cells.

Abstract: Cancer cells show constitutive upregulation of glycolysis, and the concentration of lactate thus produced correlates with prognosis. Here, we examined whether lactate concentration and lactate transporter expression are related to migration and invasion activity. We found that the expression of the monocarboxylate transporters MCT1 and MCT4, but not MCT5, in human lung cancer cell lines was significantly correlated with invasiveness. To clarify the effects of MCT1 and MCT4 expression on invasion, we performed migration and invasion assays after transfection with siRNA specific for MCT1 or MCT4. Knockdown of MCT1 or MCT4 did not influence cell migration but reduced invasion; this was also observed for knockdown of the lactate transporter-associated protein basigin. We also demonstrated that both expression and activity of MMP9 and MMP2 were not correlated with invasion activity and not regulated by MCT1, MCT4 and basigin. Furthermore, the addition of lactate did not increase migration and invasion activity, but low concentration of 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), a general anion channel blocker, as well as other MCT inhibitors quercetin and simvastatin, inhibited cell invasion without influencing migration activity and the cellular expression of MCT1 and MCT4. This is the first report suggesting that lactate transporters are involved in human cancer cell invasiveness. As such, these proteins may be promising targets for the prevention of cancer invasion and metastasis.

MiR‐195, miR‐196b, miR‐181c, miR‐21 expression levels and O‐6‐methylguanine‐DNA methyltransferase methylation status are associated with clinical outcome in glioblastoma patients

Abstract: Glioblastoma multiforme (GBM) is the most frequently occurring primary malignant brain tumor; patients with GBM often have a very poor prognosis and differing responses to treatment. Therefore, it is very important to find new biomarkers that can predict clinical outcomes and help in treatment decisions. MicroRNAs are small, non-coding RNAs that function as post-transcriptional regulators of gene expression and play a key role in the pathogenesis of GBM. In a group of 38 patients with primary GBM, we analyzed the expression of eight microRNAs (miR-21, miR-128a, miR-181c, miR-195, miR-196a, miR-196b, miR-221, and miR-222). In addition, we examined the methylation status of O-6-methylguanine-DNA methyltransferase (MGMT) promoter by high-resolution melting analysis, as this has been shown to be a predictive marker in GBM. MGMT methylation status correlated with progression-free survival (P = 0.0201; log-rank test) as well as with overall survival (P = 0.0054; log-rank test). MiR-195 (P = 0.0124; log-rank test) and miR-196b (P = 0.0492; log-rank test) positively correlated with overall survival. Evaluation of miR-181c in combination with miR-21 predicted time to progression within 6 months of diagnosis with 92% sensitivity and 81% specificity (P < 0.0001). Our data confirmed that the methylation status of MGMT but also miR-21, miR-181c, miR-195, and miR-196b to be associated with survival of GBM patients. Above all, we suggest that the combination of miR-181c and miR-21 could be a very sensitive and specific test to identify patients at high risk of early progression after surgery.

Matrix metalloproteinase-9 cooperates with transcription factor Snail to induce epithelial-mesenchymal transition.

Abstract: One of the most fundamental biological processes in tumor metastasis is the process of epithelial–mesenchymal transition (EMT). During EMT, zinc-finger-family of transcription factors such as Snail, Slug and Twist, and matrix metalloproteinases (MMPs) are upregulated, and this correlates with increased tumor cell invasion and motility. We previously obtained a highly invasive A431-III tumor subline, which is a rich source of MMP-9 and observed a plausible link between MMP levels and the promotion of EMT. To gain further understanding of EMT, we investigated the contribution of distinct MMPs to the induction of EMT. Exposing A431, cervical carcinoma parental cells, to MMP-9 stimulated a phenotypic alteration and cells became spindle-like as shown for A431-III cells. In the present communication, we document changes in gene expression profiles of A431-P and A431-III cells, including those of genes involved in cell adhesion, cytoskeleton reorganization, polarity, migration and transcription. Treatment of both A431-P and A431-III cells with GM6001, a broad spectrum MMP inhibitor, resulted in the diminution of vimentin and fibronectin, indicating a role for MMP-9 in the induction of EMT. Abrogation of MMP-9-mediated cell–cell contact in both A431-P and A431-III cells using MMP-9 siRNA resulted in decreased cell invasion, motility and altered cytoskeleton arrangement together with a reduction in Snail expression. Knockdown of Snail resulted in similar changes along with diminished MMP-9 expression. These data suggest a higher capacity of MMP-9 than that of Snail in eliciting the development of EMT in A431 cells. Based on these findings, we speculate that the overexpression of MMP-9 in A431-III cells might directly induce (or stimulate) EMT and that the transcriptional factor, Snail, could cooperatively engage in this phenomenon. (Cancer Sci 2011; 102: 815–827)

New cancer treatment strategy using combination of green tea catechins and anticancer drugs

Abstract: Green tea is now recognized as the most effective cancer preventive beverage. In one study, 10 Japanese-size cups of green tea daily supplemented with tablets of green tea extract limited the recurrence of colorectal polyps in humans to 50%. Thus, cancer patients who consume green tea and take anticancer drugs will have double prevention. We studied the effects of combining (-)-epigallocatechin gallate (EGCG) and anticancer drugs, focusing on inhibition of cell growth and induction of apoptosis. Numerous anticancer drugs, such as tamoxifen, COX-2 inhibitors, and retinoids were used for the experiments, and the combination of EGCG and COX-2 inhibitors consistently induced the enhancement of apoptosis. To study the mechanism of the enhancement, we paid special attention to the enhanced expressions of DDIT3 (growth arrest and DNA damage-inducible 153, GADD153), GADD45A, and CDKN1A (p21/WAF1/CIP1) genes, based on our previous evidence that a combination of EGCG and sulindac specifically induced upregulated expression of GADD153 and p21 genes in PC-9 lung cancer cells. The synergistic enhancements of apoptosis and GADD153 gene expression in human non-small cell lung cancer cells by the combination of EGCG and celecoxib were mediated through the activation of the MAPK signaling pathway. This article reviews the synergistic enhancement of apoptosis, gene expression, and anticancer effects using various combinations of EGCG and anticancer drugs, including the combination of (-)-epicatechin (EC) and curcumin. Based on the evidence, we present a new concept: green tea catechins as synergists with anticancer drugs.

Broad spectrum and potent antitumor activities of YM155, a novel small-molecule survivin suppressant, in a wide variety of human cancer cell lines and xenograft models.

Abstract: Antitumor activities of YM155, a novel small-molecule survivin suppressant, were investigated in a wide variety of human cancer cell lines and xenograft models. YM155 inhibited the growth of 119 human cancer cell lines, with the greatest activity in lines derived from non-Hodgkin's lymphoma, hormone-refractory prostate cancer, ovarian cancer, sarcoma, non-small-cell lung cancer, breast cancer, leukemia and melanoma. The mean log growth inhibition of 50% (GI(50) ) value was 15 nM. The mean GI(50) values of YM155 were 11 nM for p53 mut/null cell lines and 16 nM for p53 WT cell lines, suggesting that YM155 inhibits the growth of human tumor cell lines regardless of their p53 status. In non-small-cell lung cancer (Calu 6, NCI-H358), melanoma (A375), breast cancer (MDA-MB-231) and bladder cancer (UM-UC-3) xenograft models, 3- or 7-day continuous infusions of YM155 (1-10 mg/kg) demonstrated significant antitumor activity without showing significant bodyweight loss. Tumor regressions induced by YM155 were associated with reduced intratumoral survivin expression levels, increased apoptosis and decreased mitotic indices. The broad and potent antitumor activity presented in the present study is indicative of the therapeutic potential of YM155 in the clinical setting.

Bufalin and cinobufagin induce apoptosis of human hepatocellular carcinoma cells via Fas- and mitochondria-mediated pathways.

Abstract: Bufadienolides bufalin and cinobufagin are cardiotonic steroids isolated from the skin and parotid venom glands of the toad Bufo bufo gargarizans Cantor. They have been shown to induce a wide spectrum of cancer cell apoptosis. However, the detailed molecular mechanisms of inducing apoptosis in hepatocellular carcinoma (HCC) are still unclear. In the present study, the apoptosis-inducing effect of bufalin and cinobufagin on HCC cell line HepG(2) was investigated. We found bufalin and cinobufagin induced marked changes in apoptotic morphology and significantly increased the proportion of apoptotic cells. This apoptotic induction was associated with an increase in Fas, Bax and Bid expression, a decrease in Bcl-2 expression, disruption of the mitochondrial membrane potential, release of cytochrome c, activation of caspase-3, -8, -9 and -10, and the cleavage of poly(ADP-ribose)polymerase (PARP), which indicated that bufalin and cinobufagin induced apoptosis through both Fas- and mitochondria-mediated pathways. In addition, caspase activation during bufalin- and cinobufagin-induced apoptosis was further confirmed by caspase-3 inhibitor Z-DEVD-FMK, caspase-8 inhibitor Z-IETD-FMK, caspase-9 inhibitor Z-LEHD-FMK and caspase-10 inhibitor Z-AEVD-FMK. The results showed that bufalin- and cinobufagin-induced apoptosis was blocked by these inhibitors and particularly by caspase-10 inhibitor. Taken together, bufalin and cinobufagin induce apoptosis of HepG(2) cells via both Fas- and mitochondria-mediated pathways, and a Fas-mediated caspase-10-dependent pathway might play a crucial role.

Tribbles in disease: Signaling pathways important for cellular function and neoplastic transformation.

Abstract: The tribbles family of genes encodes pseudokinase proteins that are highly conserved in evolution. Instead of direct phosphorylation of target proteins, tribbles act as adaptors in signaling pathways for important cellular processes. These include mitogen-activated protein kinase kinase (MAPKK), CCAAT/enhancer-binding protein (C/EBP), activating transcription factor 4 (ATF4) and C/EBP-homologous protein (CHOP). Trib1 and Trib2 have been identified as myeloid oncogenes, and both may be involved in human leukemia. Tribbles proteins are also involved in a series of non-neoplastic disorders including metabolic and neurological diseases. The RAS/mitogen-activated protein kinase (MAPK) pathway molecules (in particular MAPK/ERK kinase 1 (MEK1) and C/EBP transcription factors) include tribbles-binding proteins that are involved in leukemogenesis, and the role of Trib1 as a linker between MAPK signaling and C/EBP degradation is proposed. Although the molecular function of tribbles is still under investigation, the research on tribbles in cellular processes, homeostasis of organisms and human diseases will provide valuable information for therapy of cancer as well as non-neoplastic disorders. (Cancer Sci 2011; 102: 1115–1122)

Wnt‐5a signaling is correlated with infiltrative activity in human glioma by inducing cellular migration and MMP‐2

Abstract: Wnts are secreted ligands that consist of 19 members in humans, regulate cell proliferation, differentiation, motility and fate in many stages including the embryonic stage and tumorigenesis Wnts bind to cell surface receptors named Frizzleds and LRPs, and transduce their signals through β-catenin-dependent and -independent intracellular pathways Gliomas are one of the most common intracranial tumors Gliomas exhibit a progression associated with widespread infiltration into surrounding neuronal tissues However, the molecular mechanisms that stimulate the invasion of glioma cells are not fully understood We established two cell lines from human glioma cases and analyzed the expression of all Wnt and Frizzled members in these cell lines and other well-known glioma cell lines by real-time PCR study The mRNA of Wnt-5a and -7b and Frizzled-2, -6 and -7 were overexpressed in glioma cells The elevation of Wnt-5a expression was most remarkable Although Wnt-5a is reported to have oncogenic and antioncogenic activity in several cancers, the role of Wnt-5a signaling in human glioma cells remains unclear Immunohistochemical study also revealed high expression of Wnt-5a in 26 (79%) of 33 human glioma cases The positivity of Wnt-5a expression was correlated with the clinical grade Knockdown of Wnt-5a expression suppressed migration, invasion and expression of matrix metalloproteinase-2 of glioma cells Reciprocally, treatment with purified Wnt-5a ligand resulted in stimulation of cell migration and invasion MMP-2 inhibitor suppressed the Wnt-5a-dependent invasion of U251 cells These results suggested that Wnt-5a is not only a prognostic factor but also a therapeutic target molecule in gliomas for preventing tumor cell infiltration (Cancer Sci 2011; 102: 540–548)

Comparison of the pharmacokinetics and pharmacodynamics of S-1 between Caucasian and East Asian patients.

Abstract: S-1 is an oral fluoropyrimidine anti-neoplastic agent that is converted by CYP2A6 to 5-fluorouracil (5FU). We prospectively studied the pharmacokinetics and pharmacodynamics of S-1 in two groups of East Asian and Caucasian patients with solid malignancy refractory to standard chemotherapy, or for which 5FU was indicated, to elucidate differences in relation to CYP2A6 genotype and phenotype. S-1 was given orally at 30 mg/m(2) b.i.d. for 14 days every 21 days. Dose normalized AUC(0-48 h) for tegafur (P = 0.05) and gimeracil (P = 0.036) were higher in East Asians; conversely, AUC(0-48 h) of fluoro-β-alanine was higher in Caucasians (P = 0.044). Exposure to 5FU was similar in both groups (P = 0.967). Mean cotinine:nicotine ratio was 54% higher in the Caucasian group (P = 0.03), and correlated with oral clearance of tegafur (r = 0.59; P = 0.002). Grade 3/4 gastrointestinal toxicities were more common in Caucasians than Asians (21%vs 0%). Treatment with S-1 yields no significant difference in 5FU exposure between Caucasians and East Asians.

Corosolic acid inhibits glioblastoma cell proliferation by suppressing the activation of signal transducer and activator of transcription-3 and nuclear factor-kappa B in tumor cells and tumor-associated macrophages

Abstract: Tumor-associated macrophages (TAM) of M2 phenotype promote tumor proliferation and are associated with a poor prognosis in patients with glioblastoma. We screened the natural compounds possessing an inhibitory effect on M2 polarization in human monocyte-derived macrophages. Among 130 purified natural compounds examined, corosolic acid significantly inhibited the expression of CD163, one of the phenotype markers of M2 macrophages, and also suppressed the secretion of IL-10, one of the anti-inflammatory cytokines preferentially produced by M2 macrophages, thus suggesting that corosolic acid suppresses M2 polarization of macrophages. Furthermore, corosolic acid inhibited the proliferation of glioblastoma cells, U373 and T98G, and the activation of signal transducer and activator of transcription-3 (STAT3) and nuclear factor-kappa B (NF-κB) in both human macrophages and glioblastoma cells. These results indicate that corosolic acid suppresses the M2 polarization of macrophages and tumor cell proliferation by inhibiting both STAT3 and NF-κB activation. Therefore, corosolic acid might be a potential new tool for tumor prevention and therapy.

Efficacy of gefitinib for non‐adenocarcinoma non‐small‐cell lung cancer patients harboring epidermal growth factor receptor mutations: A pooled analysis of published reports

Abstract: The efficacy of gefitinib for patients with non-adenocarcinoma non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations is unclear, because only a small percentage of patients enrolled in the clinical trials to evaluate the efficacy of gefitinib for tumors harboring EGFR mutation were non-adenocarcinoma NSCLC. A pooled analysis was conducted to clarify the efficacy of gefitinib for non-adenocarcinoma NSCLC patients harboring EGFR mutations. A systematic search of the PUBMED databases was conducted to identify all clinical reports that contained advanced non-adenocarcinoma NSCLC patients harboring EGFR mutations and treated with gefitinib. The selected patients were advanced non-adenocarcinoma NSCLC patients harboring EGFR mutations who were treated with gefitinib and described in reports containing the data of the histology, status of EGFR mutations and response to gefitinib. This study selected 33 patients from 15 reports. Twenty-seven and three of the 33 patients were squamous cell carcinoma and adenosquamous cell carcinoma, respectively. One patient each had large-cell carcinoma, pleomorphic carcinoma and spindle cell carcinoma. Twenty-one patients (64%) had sensitive EGFR mutations. The response rate (RR), disease control rate (DCR) and median progression-free survival (mPFS) was 27%, 67-70% and 3.0 months, respectively. These factors were statistically significantly inferior in the non-adenocarcinoma NSCLC patients harboring EGFR mutations to adenocarcinoma patients harboring EGFR mutations selected from the same published reports (RR: 27%vs 66%, P = 0.000028; DCR: 67-70%vs 92-93%, P = 0.000014; mPFS: 3.0 vs 9.4 months, P = 0.0001, respectively). Gefitinib is less effective in non-adenocarcinoma NSCLC harboring EGFR mutations than adenocarcinoma harboring EGFR mutations.

Secondary mutations of BRCA1/2 and drug resistance

Abstract: Inherited mutations in the tumor suppressor genes BRCA1 and BRCA2 cause increased risk of developing various cancers, especially breast and ovarian cancers. Tumors that develop in patients with inherited BRCA1/2 mutations are generally believed to be BRCA1/2-deficient. Cancer cells with BRCA1/2 deficiency are defective in DNA repair by homologous recombination and sensitive to interstrand DNA crosslinking agents, such as cisplatin and carboplatin, and poly(ADP-ribose) polymerase inhibitors. Therefore, these agents are logical choices for the treatment for BRCA1/2-deficient tumors and have shown to be clinically effective. However, BRCA1/2-mutated tumors often develop resistance to these drugs. Restoration of BRCA1/2 functions due to secondary BRCA1/2 mutations has been recognized as a mechanism of acquired resistance to cisplatin and poly(ADP-ribose) polymerase inhibitors in BRCA1/2-mutated cancer cells. This indicates that even disease-causing inherited mutations of tumor suppressor genes can be genetically reverted in cancer cells, if the genetic reversion is advantageous for the cells' survival. In this review, we will discuss this drug resistance mechanism.

Primary gastrointestinal follicular lymphoma involving the duodenal second portion is a distinct entity: A multicenter, retrospective analysis in Japan

Abstract: We conducted a multicenter, retrospective study to determine the anatomical distribution and prognostic factors of gastrointestinal (GI) follicular lymphoma (FL). This study included 125 patients with stage I and II(1) GI-FL. Of the 125 patients, the small intestine was examined in 70 patients, with double-balloon endoscopy and/or capsule endoscopy. The most frequently involved GI-FL site was the duodenal second portion (DSP) (81%), followed by the jejunum (40%); 85% of patients with involvement of the DSP also had jejunal or ileal lesions. The absence of abdominal symptoms and macroscopic appearance of multiple nodules were significantly present in the DSP-positive group. During a median follow up of 40 months, six patients showed disease progression. Patients with involvement of the DSP had better progression-free survival (PFS) than those without such involvement (P = 0.001). A multivariate analysis revealed that male sex, the presence of abdominal symptoms, and negative involvement of the DSP were independently associated with poor PFS. In conclusion, most patients with GI-FL have duodenal lesions associated with multiple jejunal or ileal lesions. Gastrointestinal follicular lymphomas involving the DSP might be a distinct entity showing a favorable clinical course.

Critical role of aquaporin 3 on growth of human esophageal and oral squamous cell carcinoma

Abstract: Aquaporins (AQP) play important roles in water and glycerol transport. We examined whether AQP3 is expressed in primary squamous cell carcinoma (SCC) such as esophageal and oral cancer and lymph node metastasis, and whether AQP3 is a potential target for tumor therapy. A high level expression of AQP3 was observed in tumor areas of human primary SCC such as esophageal and lingual cancers, and lymph node metastasis, but was not observed in normal areas. Treatment with pan-AQP inhibitor caused apoptotic cell death on the SCC cell lines in a concentration-dependent manner. Small interfering RNA (siRNA) specific for AQP3 also inhibited cell adhesion and growth of SCC, but not those of adenocarcinoma cell lines and fibroblasts. Expression of integrin α5 and β1, counter adhesion molecules for fibronectin, was inhibited by treatment with AQP3-siRNA. The phosphorylation of focal adhesion kinase (FAK) was decreased by treatment with AQP3-siRNA, which then caused decreases in phosphorylation of Erk and MAPK. These results indicate that the decreases in integrins and the inhibition of cell adhesion might cause inhibition of the FAK signaling pathways. Combination of AQP3-siRNA with cisplatin, a major anti-cancer drug, strongly inhibited the growth of SCC. Cell death caused by the inhibition of AQP3 was a result of direct interference with cell adhesion involving intracellular FAK-MAPK signaling pathways. These results imply a potentially important and novel role for the inhibition of AQP3 function via the use of specific siRNA in the treatment of SCC.

Transforming growth factor‐beta 2 gene silencing with trabedersen (AP 12009) in pancreatic cancer

Abstract: Pancreatic cancer is one of the most aggressive human cancers with a 5-year survival rate of <5%. Overexpression of transforming growth factor-beta 2 (TGF-β2) in pancreatic malignancies is suggested to be a pivotal factor for malignant progression by inducing immunosuppression, metastasis, angiogenesis and proliferation. Trabedersen (AP 12009) is a phosphorothioate antisense oligodeoxynucleotide specific for human TGF-β2 mRNA and was successfully tested in a randomized, active-controlled phase IIb clinical study in patients with high-grade glioma. Here, we report on the antitumor activity of trabedersen in human pancreatic cancer cells and in an orthotopic xenograft mouse model of human metastatic pancreatic cancer. Trabedersen reduced TGF-β2 secretion in human pancreatic cell lines with an IC50 in the low μM range without transfection reagent, clearly inhibited cell proliferation, and completely blocked migration of pancreatic cancer cells. Additionally, trabedersen reversed TGF-β2-mediated immunosuppression of pancreatic cancer cells targeted by lymphokine activated killer (LAK) cells, resulting in considerably increased LAK cell-mediated cytotoxicity. Moreover, in an orthotopic mouse model of metastatic pancreatic cancer, intraperitoneal (i.p.) treatment with trabedersen significantly reduced tumor growth, lymph node metastasis and angiogenesis. These promising results warrant further clinical development of trabedersen. Cancer Sci 2011; 102: 1193–1200)

Hispidulin, a small flavonoid molecule, suppresses the angiogenesis and growth of human pancreatic cancer by targeting vascular endothelial growth factor receptor 2-mediated PI3K/Akt/mTOR signaling pathway.

Abstract: Hispidulin, an active component from Artemisia vestita ,a traditional Tibetan medicinal plant, has been shown to possess anti-inflammatory and anti-oxidative activities. However, the functional role of hispidulin on tumor growth and angiogenesis has not been elucidated. We found that hispidulin significantly inhibited human pancreatic tumor growth in xenograft mice when s.c. treated at a dosage of 20 mg/kg daily, and this effect was accompanied with a potent inhibition on angiogenesis. When examining the cytotoxicity of hispidulin on HUVECs and pancreatic cancer cells in vitro, we found that HUVECs were more susceptible to the treatment, suggesting angiogenesis might be the primary target of hispidulin. Our results further showed that hispidulin inhibited vascular endothelial growth factor (VEGF)-induced cell migration, invasion, and capillary-like structure formation of HUVECs in a dose-dependent manner. In ex vivo and in vivo angiogenesis assays, we showed that hispidulin suppressed VEGF-induced microvessel sprouting of rat aortic rings and corneal neovascularization in C57/BL6 mice. To understand the underlying molecular basis, we next examined the effects of hispidulin on different molecular components in treated HUVECs, and found that hispidulin suppressed the VEGF-triggered activation of VEGF receptor 2, PI3K, Akt, mTOR, and ribosomal protein S6 kinase, but had little effect on focal adhesion kinase or extracellular signal-regulated kinase at an effective concentration. Taken together, our results indicate that hispidulin targets the VEGF receptor 2-mediated PI3K/Akt/mTOR signaling pathway in endothelial cells, leading to the suppression of pancreatic tumor growth and angiogenesis. (Cancer Sci 2011; 102: 219‐225)

Clinical utility of highly sensitive Lens culinaris agglutinin-reactive alpha-fetoprotein in hepatocellular carcinoma patients with alpha-fetoprotein <20 ng/mL

Abstract: The Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein (AFP-L3) has been used as a diagnostic and prognostic marker of hepatocellular carcinoma (HCC). The analytical sensitivity of a conventional method for AFP-L3% is not sufficient in patients with a low AFP level. This study was performed to determine the clinical utility of a newly developed highly sensitive AFP-L3% (hs-AFP-L3%) assay in patients with an AFP level <20 ng/mL. In the cohort study, serum samples obtained from 270 patients with newly diagnosed HCC before treatment and 396 patients with chronic liver disease at Ogaki Municipal Hospital, in both of which the AFP level was <20 ng/mL, were measured for conventional AFP-L3% (c-AFP-L3%), hs-AFP-L3% and des-gamma-carboxy prothrombin (DCP). Diagnostic sensitivity and specificity of hs-AFP-L3% at a cut-off level of 5% were 41.5% and 85.1%, respectively, significantly increasing the sensitivity from 7.0% for c-AFP-L3%. Multivariate analysis identified hs-AFP-L3% as an independent factor associated with reduced long-term survival. The survival rate of patients with high hs-AFP-L3% (≥ 5%) before treatment was significantly poorer than that of patients with low hs-AFP-L3% (<5%) (P < 0.001). In patients with AFP <20 ng/mL, measurements of AFP-L3% by the highly sensitive method before treatment were more useful for diagnosis and prognosis of HCC than by the conventional method.

Mechanisms of resistance to anti-human epidermal growth factor receptor 2 agents in breast cancer.

Abstract: Approximately 20% of breast cancers are characterized by overexpression of human epidermal growth factor receptor 2 (HER2) protein and associated gene amplification, and the receptor tyrosine kinase is believed to play a critical role in the pathogenesis of these tumors. The development and implementation of trastuzumab, a humanized monoclonal antibody against the extracellular domain of HER2 protein, has significantly improved treatment outcomes in patients with HER2-overexpressing breast cancer. However, despite this clinical usefulness, unmet needs for better prediction of trastuzumab's response and overcoming primary and acquired resistance remain. In this review, we discuss several potential mechanisms of resistance to trastuzumab that have been closely studied over the last decade. Briefly, these mechanisms include: impaired access of trastuzumab to HER2 by expression of extracellular domain-truncated HER2 (p95 HER2) or overexpression of MUC4; alternative signaling from insulin-like growth factor-1 receptor, other epidermal growth factor receptor family members, or MET; aberrant downstream signaling caused by loss of phosphatase and tensin homologs deleted from chromosome 10 (PTEN), PIK3CA mutation, or downregulation of p27; or FCGR3A polymorphisms. In addition, we discuss potential strategies for overcoming resistance to trastuzumab. Specifically, the epidermal growth factor receptor/HER2 tyrosine kinase inhibitor lapatinib partially overcame trastuzumab resistance in a clinical setting, so its efficacy results and limited data regarding potential mechanisms of resistance to the drug are also discussed.

Essential role of the Hedgehog signaling pathway in human glioma-initiating cells

Abstract: Recent findings have demonstrated that malignant tumors, including glioblastoma multiforme, contain cancer-initiating cells (also known as cancer stem cells), which self-renew and are malignant, with features of tissue-specific stem cells. As these cells are resistant to irradiation and anti-cancer drugs, it is important to characterize them and find targeting therapies. In this study, we established two primary human glioma cell lines from anaplastic oligodendroglioma and glioblastoma multiforme. These lines were enriched in glioma-initiating cells, as just 10 cells formed malignant glioma when injected into mouse brain. We used these cell lines to examine the roles of the Notch, Hedgehog and Wnt signaling pathways, which are involved in stem-cell maintenance and tumorigenesis, to determine which of these pathways are crucial to glioma-initiating cells and their regulation. Here we show that the Hedgehog pathway is indispensable for glioma-initiating cell proliferation and tumorigenesis; the Hedgehog signaling inhibitors prevented glioma-initiating cell proliferation, while signaling inhibitors for Notch or Wnt did not. Overexpression of Gli2ΔC, a C-terminal-truncated form of Gli2 that antagonizes Gli transcription factor functions, blocked glioma-initiating cell proliferation in culture and tumorigenesis in vivo. Knockdown of the Gli downstream factor Cdc2 also prevented glioma-initiating cell proliferation. Taken together, these results show that the Hedgehog→ Gli→Cdc2 signaling cascade plays a role in the proliferation and malignancy of glioma-initiating cells.