Showing papers in "International Journal of Cancer in 2011"

Regorafenib (BAY 73-4506): a new oral multikinase inhibitor of angiogenic, stromal and oncogenic receptor tyrosine kinases with potent preclinical antitumor activity

Abstract: Angiogenesis, a critical driver of tumor development, is controlled by interconnected signaling pathways. Vascular endothelial growth factor receptor (VEGFR) 2 and tyrosine kinase with immunoglobulin and epidermal growth factor homology domain 2 play crucial roles in the biology of normal and tumor vasculature. Regorafenib (BAY 73-4506), a novel oral multikinase inhibitor, potently inhibits these endothelial cell kinases in biochemical and cellular kinase phosphorylation assays. Furthermore, regorafenib inhibits additional angiogenic kinases (VEGFR1/3, platelet-derived growth factor receptor-β and fibroblast growth factor receptor 1) and the mutant oncogenic kinases KIT, RET and B-RAF. The antiangiogenic effect of regorafenib was demonstrated in vivo by dynamic contrast-enhanced magnetic resonance imaging. Regorafenib administered once orally at 10 mg/kg significantly decreased the extravasation of Gadomer in the vasculature of rat GS9L glioblastoma tumor xenografts. In a daily (qd)×4 dosing study, the pharmacodynamic effects persisted for 48 hr after the last dosing and correlated with tumor growth inhibition (TGI). A significant reduction in tumor microvessel area was observed in a human colorectal xenograft after qd×5 dosing at 10 and 30 mg/kg. Regorafenib exhibited potent dose-dependent TGI in various preclinical human xenograft models in mice, with tumor shrinkages observed in breast MDA-MB-231 and renal 786-O carcinoma models. Pharmacodynamic analyses of the breast model revealed strong reduction in staining of proliferation marker Ki-67 and phosphorylated extracellular regulated kinases 1/2. These data demonstrate that regorafenib is a well-tolerated, orally active multikinase inhibitor with a distinct target profile that may have therapeutic benefit in human malignancies.

Human papillomavirus type distribution in 30,848 invasive cervical cancers worldwide: Variation by geographical region, histological type and year of publication.

Abstract: Pooled data on human papillomavirus (HPV) type distribution in invasive cervical cancer (ICC) can help to predict the potential impact of HPV type-specific vaccines and screening tests, and to understand the carcinogenicity of HPV types. We performed a meta-analysis of HPV type-specific prevalence data published from 1990 to 2010, including a total of 243 studies and 30,848 ICC. The proportion of ICC associated with HPV16 and/or 18 (HPV16/18) was between 70 and 76% in all world regions except Asia. In Western/Central Asia, 82% of ICC was HPV16/18-associated compared to only 68% in Eastern Asia. The 12 most common HPV types identified, in order of decreasing prevalence, were HPV16 (57%), 18 (16%), 58, 33, 45, 31, 52, 35, 59, 39, 51 and 56. The prevalence of other types, phylogenetically related to those above, ranged from <0.1% for HPV85 to 0.6% for HPV68. Overall HPV prevalence increased significantly from 85.9% in studies published from 1990 to 1999 to 92.9% in studies published from 2006 to 2010. Prevalence increases were large for multiple infections (from 4.0 to 15.7%) and for HPV16 (from 51.8 to 60.0%, including HPV16 alone or in multiple infections). Smaller but significant increases in prevalence were also seen for HPV39, 53 and 58. A large amount of recently published data has improved the understanding of the contribution of a broad range of HPV types to ICC in different world regions. However, estimating the fraction of ICC attributable to different types is increasingly complicated by the detection of multiple HPV infections in ICC.

The seed and soil hypothesis revisited-The role of tumor-stroma interactions in metastasis to different organs

Abstract: The fact that certain tumors exhibit a predilection for metastasis to specific organs has been recognized for well over a century now. An extensive body of clinical data and experimental research has confirmed Stephen Paget's original "seed and soil" hypothesis that proposed the organ-preference patterns of tumor metastasis are the product of favorable interactions between metastatic tumor cells (the "seed") and their organ microenvironment (the "soil"). Indeed, many of the first-line therapeutic regimens, currently in use for the treatment of human cancer are designed to target cancer cells (such as chemotherapy) and also to modulate the tumor microenvironment (such as antiangiogenic therapy). While some types of tumors are capable of forming metastases in virtually every organ in the body, the most frequent target organs of metastasis are bone, brain, liver and the lung. In this review, we discuss how tumor-stromal interactions influence metastasis in each of these organs.

Circulating miRNAs are correlated with tumor progression in prostate cancer.

Abstract: Circulating miRNAs have recently been indicated as practicable and promising biomarkers for noninvasive diagnosis in various tumor entities. However, cell-free miRNAs have not been found to correlate with clinicopathological variables in epithelial carcinomas. To learn more about the potential clinical relevance of circulating miRNAs in prostate cancer, we screened 667 miRNAs in serum samples from patients with metastatic (n = 7) and localized prostate cancer (n = 14). Various miRNAs were highly abundant in the sera of patients with metastatic disease, and five upregulated miRNAs (miRNA-375, miRNA-9*, miRNA-141, miRNA-200b and miRNA-516a-3p) were selected for further validation. In the first validation study (n = 45), selected miRNAs were analyzed in a prospectively collected serum set taken from different prostate cancer risk groups. Most of the selected miRNAs were significantly correlated with adverse risk factors when different clinicopathological variables were analyzed. Circulating miRNA-375 and miRNA-141 turned out to be the most pronounced markers for high-risk tumors. Their levels also correlated with high Gleason score or lymph-node positive status in a second independent validation study (n = 71). In addition, the expression levels of miRNA-375 and miRNA-141 were monitored in 72 prostate tissue samples (36 tumor vs. 36 benign). Both miRNAs were highly expressed in all samples and significantly upregulated in the tumors compared to normal tissues. Overall, our observations suggest that miRNA-375 and miRNA-141 expression is enhanced in prostate cancer specimens and their release into the blood is further associated with advanced cancer disease.

Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma

Abstract: Epidemiological studies have suggested a reduced risk of several cancers associated with high vitamin D status. We performed a systematic review with meta-analyses of observational studies of serum 25-hydroxyvitamin D level and colorectal, breast and prostate cancer and colonic adenoma. The literature of December 2009 was searched without language restriction. The meta-regression analysis was done to compute dose-response effects. Because in case-control studies, serum 25-hydroxyvitamin D level is measured after the diagnosis of cancer, separate analyses for case-control and prospective studies were done. We identified 35 independent studies. The seven studies on colorectal adenomas were heterogeneous in terms of endpoint and control for major confounding factors, and we did not perform a meta-analysis of these data. The summary relative risk (SRR) and (95% confidence interval) for a 10 ng/ml increase in serum 25-hydroxyvitamin D was 0.85 (0.79; 0.91) for colorectal cancer (2,630 cases in 9 studies); 0.89 (0.81;0.98) for breast cancer (6,175 cases in 10 studies); and 0.99 (0.95;1.03) for prostate cancer (3,956 cases in 11 studies). For breast cancer, case-control studies (3,030 cases) had major limitations and obtained SRR of 0.83 (0.79; 0.87) whereas SRR of prospective studies (3,145 cases) was 0.97 (0.92; 1.03). For colorectal and breast cancer, differences between cases and controls in the season of blood draw or in overweight/obesity or physical inactivity could not explain the results. In conclusion, a consistent inverse relationship between serum 25-hydroxyvitamin D levels and colorectal cancer was found. No association was found for breast and prostate cancer.

Overexpression of LSD1 contributes to human carcinogenesis through chromatin regulation in various cancers.

Abstract: A number of histone demethylases have been identified and biochemically characterized, but the pathological roles of their dysfunction in human disease like cancer have not been well understood. Here, we demonstrate important roles of lysine-specific demethylase 1 (LSD1) in human carcinogenesis. Expression levels of LSD1 are significantly elevated in human bladder carcinomas compared with nonneoplastic bladder tissues (p < 0.0001). cDNA microarray analysis also revealed its transactivation in lung and colorectal carcinomas. LSD1-specific small interfering RNAs significantly knocked down its expression and resulted in suppression of proliferation of various bladder and lung cancer cell lines. Concordantly, introduction of exogenous LSD1 expression promoted cell cycle progression of human embryonic kidney fibroblast cells. Expression profile analysis showed that LSD1 could affect the expression of genes involved in various chromatin-modifying pathways such as chromatin remodeling at centromere, centromeric heterochromatin formation and chromatin assembly, indicating its essential roles in carcinogenesis through chromatin modification.

Non-alcoholic fatty liver disease progresses to hepatocellular carcinoma in the absence of apparent cirrhosis

Abstract: Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in developed countries, and accumulating evidence suggests it as the hepatic manifestation of the metabolic syndrome (MS). Although the published prevalence of hepatocellular carcinoma (HCC) is low in NAFLD/NASH patients, most of these data have been derived from areas endemic for viral hepatitis. We recruited 162 adults with HCC between February 2007 and March 2008, investigated the underlying etiologies and determined the prevalence of the MS and related features within each group. Patients with NAFLD/NASH-associated HCC exhibited a higher prevalence of metabolic features (Type 2 diabetes mellitus, hypertension, dyslipidemia, coronary artery disease) compared to non-NAFLD/NASH-HCC. Intriguingly, a significant number (41.7%; p < 0.005) of individuals with NAFLD/NASH-HCC had no evidence of cirrhosis. Patients with alcohol-induced liver disease also displayed many features (14/19, 73.7%) of the MS, although, in contrast to NAFLD/NASH-HCC, alcohol-associated HCC was highly associated with cirrhosis (95.0%; p = 0.064). NAFLD/NASH as the hepatic entity of the MS may itself pose a risk factor for HCC, even in the absence of cirrhosis. The MS may also promote development of HCC among those with alcoholic liver disease. Increased awareness of liver manifestations in the MS may instigate early interventions against developing HCC.

PD-1 and PD-L1 upregulation promotes CD8+ T-cell apoptosis and postoperative recurrence in hepatocellular carcinoma patients

Abstract: Programmed death 1 (PD-1) and its ligand (PD-L1) play pivotal roles in regulating host immune responses. However, the inhibitory effects of this pathway on the function of cytotoxic CD8(+) T lymphocytes, the main effector cells in hepatocellular carcinoma (HCC) patients, are not well defined. In this study, we characterized circulating and intratumor PD-1/PD-L1 expression and analyzed their association with disease progression in a cohort of hepatitis B virus-infected patients, including 56 with HCC, 20 with liver cirrhosis (LC) and 20 healthy controls (HC). The frequency of circulating PD-1(+) CD8(+) T cells increased with disease progression from LC to HCC patients versus HC. Furthermore, tumor-infiltrating effector CD8(+) T cells showed a drastic increase in PD-1 expression. These increases in circulating and intratumor PD-1(+) CD8(+) T cells could predict poorer disease progression and postoperative recurrence. Immunohistochemical staining showed that PD-L1 expressing hepatoma cells and apoptotic infiltrating CD8(+) T cells were both enriched in tumor sections. In vitro, CD8(+) T cells induced PD-L1 expression on hepatoma cells in an IFN-γ-dependent manner, which in turn promoted CD8(+) T cells apoptosis, and blocking PD-L1 reversed this effect. Therefore, this study extends our knowledge of the role of the PD-1/PD-L1 pathway in tumor evasion and provides evidence for a new therapeutic target in HCC patients.

Interleukin‐8 is associated with proliferation, migration, angiogenesis and chemosensitivity in vitro and in vivo in colon cancer cell line models

Abstract: Interleukin-8 (IL-8), a chemokine with a defining CXC amino acid motif, is known to possess tumorigenic and proangiogenic properties. Overexpression of IL-8 has been detected in many human tumors, including colorectal cancer (CRC), and is associated with poor prognosis. The goal of our study was to determine the role of IL-8 overexpression in CRC cells in vitro and in vivo. We stably transfected the IL-8 cDNA into two human colon cancer cell lines, HCT116 and Caco2, and selected IL-8-secreting transfectants. Real-time RT-PCR confirmed that IL-8 mRNA was overexpressed in IL-8 transfectants with 45- to 85-fold higher than parental cells. The IL-8-transfected clones secreted 19- to 28-fold more IL-8 protein than control and parental cells as detected by ELISA. The IL-8 transfectants demonstrated increased cellular proliferation, cell migration and invasion based on functional assays. Growth inhibition studies showed that IL-8 overexpression lead to a significant resistance to oxaliplatin (p < 0.0001). Inhibition of IL-8 overexpression with small interfering RNA reversed the observed increases in tumorigenic functions and oxaliplatin resistance, suggesting that IL-8 not only provides a proliferative advantage but also promotes the metastatic potential of colon cancer cells. Using a tumor xenograft model, IL-8-expressing cells formed significantly larger tumors than the control cells with increased microvessel density. Together, these findings indicate that overexpression of IL-8 promotes tumor growth, metastasis, chemoresistance and angiogenesis, implying IL-8 to be an important therapeutic target in CRC.

Coordinated epigenetic repression of the miR‐200 family and miR‐205 in invasive bladder cancer

Abstract: MicroRNAs (miRNA) are small noncoding RNAs commonly deregulated in cancer. The miR-200 family (miR-200a, -200b, -200c, -141 and -429) and miR-205 are frequently silenced in advanced cancer and have been implicated in epithelial to mesenchymal transition (EMT) and tumor invasion by targeting the transcriptional repressors of E-cadherin, ZEB1 and ZEB2. ZEB1 is also known to repress miR-200c-141 transcription in a negative feedback loop, but otherwise little is known about the transcriptional regulation of the miR-200 family and miR-205. Recently, miR-200 silencing was also reported in cancer stem cells, implying that miR-200 deregulation is a key event in multiple levels of tumor biology. However, what prevents miR-200 expression remains largely unanswered. Here we report concerted transcriptional regulation of the miR-200 and miR-205 loci in bladder tumors and bladder cell lines. Using a combination of miRNA expression arrays, qPCR assays and mass spectrometry DNA methylation analyses, we show that the miR-200 and miR-205 loci are specifically silenced and gain promoter hypermethylation and repressive chromatin marks in muscle invasive bladder tumors and undifferentiated bladder cell lines. Moreover, we report that miR-200c expression is significantly correlated with early stage T1 bladder tumor progression, and propose miR-200 and miR-205 silencing and DNA hypermethylation as possible prognostic markers in bladder cancer. In addition, we observe that the mesoderm transcription factor TWIST1 and miR-200 expression are inversely correlated in bladder tumor samples and cell lines. TWIST1 associates directly with the miR-200 and miR-205 promoters, and may act as a repressor of miR-200 and miR-205 expression.

Predictors and survival of synchronous peritoneal carcinomatosis of colorectal origin: A population-based study

Abstract: The aim of our study was to provide population-based data on incidence and prognosis of synchronous peritoneal carcinomatosis and to evaluate predictors for its development. Diagnosed in 1995-2008, 18,738 cases of primary colorectal cancer were included. Predictors of peritoneal carcinomatosis were analysed by multivariable logistic regression analysis. Median survival in months was calculated by site of metastasis. In the study period, 904 patients were diagnosed with synchronous peritoneal carcinomatosis (4.8% of total, constituting 24% of patients presenting with M1 disease). The risk of peritoneal carcinomatosis was increased in case of advanced T stage [T4 vs. T1,2: odds ratio (OR) 4.7, confidence limits 4.0-5.6), advanced N stage [N0 vs. N1,2: OR 0.2 (0.1-0.2)], poor differentiation grade [OR 2.1 (1.8-2.5)], younger age [<60 years vs. 70-79 years: OR 1.4 (1.1-1.7)], mucinous adenocarcinoma [OR 2.0 (1.6-2.4)] and right-sided localisation of primary tumour [left vs. right: OR 0.6 (0.5-0.7)]. Median survival of patients with peritoneum as single site of metastasis remained dismal [1995-2001: 7 (6-9) months; 2002-2008: 8 (6-11) months], contrasting the improvement among patients with liver metastases [1995-2001: 8 (7-9) months; 2002-2008: 12 (11-14) months]. To conclude, synchronous peritoneal metastases from colorectal cancer are more frequent among younger patients and among patients with advanced T stage, mucinous adenocarcinoma, right-sided tumours and tumours that are poorly differentiated. The prognosis of synchronous peritoneal carcinomatosis remains poor with a median survival of 8 months and even worse if concomitant metastases in other organs are present.

Detection of circulating tumor cells as a prognostic factor in patients undergoing radical surgery for non-small-cell lung carcinoma: comparison of the efficacy of the CellSearch Assay™ and the isolation by size of epithelial tumor cell method†

Abstract: Comparison of the efficacy of different enrichment methods for detection of circulating tumor cells (CTCs) before radical surgery is lacking in non-small-cell lung carcinoma (NSCLC) patients. Detection and enumeration of CTCs in 210 consecutive patients undergoing radical surgery for NSCLC were evaluated with the CellSearch Assay™ (CS), using the CellSearch Epithelial Cell Kit, and by the isolation by size of epithelial tumor (ISET) method, using double immunolabeling with anti-cytokeratin and anti-vimentin antibodies. CTCs were detected in 144 of 210 (69%) patients using CS and/or ISET and in 104 of 210 (50%) and 82 of 210 (39%) patients using ISET and CS, respectively. Using ISET, 23 of 210 (11%) patients had vimentin-positive cells with cytological criteria of malignancy. Disease-free survival (DFS) was worse for patients with CTCs compared to patients without CTCs detected by CS alone (p < 0.0001; log rank = 30.59) or by ISET alone (p < 0.0001; log rank = 33.07). The presence of CTCs detected by both CS and ISET correlated even better with shorter DFS at a univariate (p < 0.0001; log rank = 42.15) and multivariate level (HR, 1.235; 95% CI, 1.056–1.482; p < 0.001). CS and ISET are complementary methods for detection of CTCs in preoperative radical surgery for NSCLC. CTC detection in resectable NSCLC patients using CS and/or ISET could be a prognostic biomarker of great interest and may open up new avenues into improved therapeutic strategies for lung carcinoma patients.

Dysregulation of PRMT1 and PRMT6, Type I arginine methyltransferases, is involved in various types of human cancers

Abstract: Protein arginine methylation is a novel post-translational modification regulating a diversity of cellular processes, including histone functions, but the roles of protein arginine methyltransferases (PRMTs) in human cancer are not well investigated To address this issue, we first examined expression levels of genes belonging to the PRMT family and found significantly higher expression of PRMT1 and PRMT6, both of which are Type I PRMTs, in cancer cells of various tissues than in non-neoplastic cells Abrogation of the expression of these genes with specific siRNAs significantly suppressed growth of bladder and lung cancer cells Expression profile analysis using the cells transfected with the siRNAs indicated that PRMT1 and PRMT6 interplay in multiple pathways, supporting regulatory roles in the cell cycle, RNA processing and also DNA replication that are fundamentally important for cancer cell proliferation Furthermore, we demonstrated that serum asymmetric dimethylarginine (ADMA) levels of a number of cancer cases are significantly higher than those of nontumor control cases In summary, our results suggest that dysregulation of PRMT1 and PRMT6 can be involved in human carcinogenesis and that these Type I arginine methyltransferases are good therapeutic targets for various types of cancer

Promoter methylation and expression of MGMT and the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2 in paired primary and recurrent glioblastomas

Abstract: Epigenetic silencing of the O(6) -methylguanine-DNA methyltransferase (MGMT) gene promoter is associated with prolonged survival in glioblastoma patients treated with temozolomide (TMZ). We investigated whether glioblastoma recurrence is associated with changes in the promoter methylation status and the expression of MGMT and the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 in pairs of primary and recurrent glioblastomas of 80 patients, including 64 patients treated with radiotherapy and TMZ after the first operation. Among the primary tumors, the MGMT promoter was methylated in 31 patients and unmethylated in 49 patients. In 71 patients (89%), the MGMT promoter methylation status of the primary tumor was retained at recurrence. MGMT promoter methylation, but not MGMT protein expression, was associated with longer progression-free survival, overall survival and postrecurrence survival (PRS). Moreover, PRS was increased under salvage chemotherapy. Investigation of primary and recurrent glioblastomas of 43 patients did not identify promoter methylation in any of the four MMR genes. However, recurrent glioblastomas demonstrated significantly lower MSH2, MSH6 and PMS2 protein expression as detected by immunohistochemistry. In conclusion, reduced expression of MMR proteins, but not changes in MGMT promoter methylation, is characteristic of glioblastomas recurring after the current standards of care.

Reactive species and DNA damage in chronic inflammation: reconciling chemical mechanisms and biological fates.

Abstract: Chronic inflammation has long been recognized as a risk factor for many human cancers. One mechanistic link between inflammation and cancer involves the generation of nitric oxide, superoxide and other reactive oxygen and nitrogen species by macrophages and neutrophils that infiltrate sites of inflammation. Although pathologically high levels of these reactive species cause damage to biological molecules, including DNA, nitric oxide at lower levels plays important physiological roles in cell signaling and apoptosis. This raises the question of inflammation-induced imbalances in physiological and pathological pathways mediated by chemical mediators of inflammation. At pathological levels, the damage sustained by nucleic acids represents the full spectrum of chemistries and likely plays an important role in carcinogenesis. This suggests that DNA damage products could serve as biomarkers of inflammation and oxidative stress in clinically accessible compartments such as blood and urine. However, recent studies of the biotransformation of DNA damage products before excretion point to a weakness in our understanding of the biological fates of the DNA lesions and thus to a limitation in the use of DNA lesions as biomarkers. This review will address these and other issues surrounding inflammation-mediated DNA damage on the road to cancer.

MEG3 imprinted gene contribution in tumorigenesis.

Abstract: Maternally expressed gene 3 (MEG3) is a maternally expressed imprinted gene representing a large noncoding RNA in which microRNAs (miRNAs) and small nucleolar RNAs are also hosted. It is capable of interacting with cyclic AMP, p53, murine double minute 2 (MDM2) and growth differentiation factor 15 (GDF15) playing a role in cell proliferation control. MEG3 expression is under epigenetic control, and aberrant CpG methylation has been observed in several types of cancer. Moreover, gene copy number loss has been reported as additional mechanism associated with tumorigenesis. MEG3 deletion seems to upregulate the paternally expressed genes and on the other hand downregulate the expression of downstream maternally expressed genes and tumor suppressor miRNAs, although there are conflicting data on the topic. MEG3 could represent a tumor suppressor gene located in chromosome 14q32 and its association with tumorigenesis is growing every day.

A pooled analysis of 14 cohort studies of anthropometric factors and pancreatic cancer risk

Abstract: Epidemiologic studies of pancreatic cancer risk have reported null or nonsignificant positive associations for obesity, while associations for height have been null. Waist and hip circumference have been evaluated infrequently. A pooled analysis of 14 cohort studies on 846,340 individuals was conducted; 2,135 individuals were diagnosed with pancreatic cancer during follow-up. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were calculated by Cox proportional hazards models, and then pooled using a random effects model. Compared to individuals with a body mass index (BMI) at baseline between 21-22.9 kg/m(2) , pancreatic cancer risk was 47% higher (95%CI:23-75%) among obese (BMI ≥ 30 kg/m(2) ) individuals. A positive association was observed for BMI in early adulthood (pooled multivariate [MV]RR = 1.30, 95%CI = 1.09-1.56 comparing BMI ≥ 25 kg/m(2) to a BMI between 21 and 22.9 kg/m(2) ). Compared to individuals who were not overweight in early adulthood (BMI < 25 kg/m(2) ) and not obese at baseline (BMI < 30 kg/m(2) ), pancreatic cancer risk was 54% higher (95%CI = 24-93%) for those who were overweight in early adulthood and obese at baseline. We observed a 40% higher risk among individuals who had gained BMI ≥ 10 kg/m(2) between BMI at baseline and younger ages compared to individuals whose BMI remained stable. Results were either similar or slightly stronger among never smokers. A positive association was observed between waist to hip ratio (WHR) and pancreatic cancer risk (pooled MVRR = 1.35 comparing the highest versus lowest quartile, 95%CI = 1.03-1.78). BMI and WHR were positively associated with pancreatic cancer risk. Maintaining normal body weight may offer a feasible approach to reducing morbidity and mortality from pancreatic cancer.

The cancer stem cell niche—there goes the neighborhood?

Abstract: The niche is the environment in which stem cells reside and is responsible for the maintenance of unique stem cell properties such as self-renewal and an undifferentiated state. The heterogeneous populations which constitute a niche include both stem cells and surrounding differentiated cells. This network of heterogeneity is responsible for the control of the necessary pathways that function in determining stem cell fate. The concept that cancer stem cells, a subpopulation of cells responsible for tumor initiation and formation, reside in their own unique niche is quickly evolving and it is of importance to understand and identify the processes occurring within this environment. The necessary intrinsic pathways that are utilized by this cancer stem cell population to maintain both self-renewal and the ability to differentiate are believed to be a result of the environment where cancer stem cells reside. The ability of a specific cancer stem cell niche to provide the environment in which this population can flourish is a critical aspect of cancer biology that mandates intense investigation. This review focuses on current evidence demonstrating that homeostatic processes such as inflammation, epithelial to mesenchymal transition, hypoxia and angiogenesis contribute to the maintenance and control of cancer stem cell fate by providing the appropriate signals within the microenvironment. It is necessary to understand the key processes occurring within this highly specialized cancer stem cell niche to identify potential therapeutic targets that can serve as the basis for development of more effective anticancer treatments.

Polymorphonuclear granulocytes in human head and neck cancer: enhanced inflammatory activity, modulation by cancer cells and expansion in advanced disease.

Abstract: The progression of epithelial cancer is associated with an intense immunological interaction between the tumor cells and immune cells of the host. However, little is known about the interaction between tumor cells and polymorphonuclear granulocytes (PMNs) in patients with head and neck squamous cell carcinoma (HNSCC). In our study, we investigated systemic PMN-related alterations in HNSCC, the role of tumor-infiltrating PMNs and their modulation by the tumor microenvironment. We assessed the infiltration of HNSCC tissue by PMNs (retrospectively) and systemic PMN-related alterations in blood values (prospectively) in HNSCC patients (n = 99 and 114, respectively) and control subjects (n = 41). PMN recruitment, apoptosis and inflammatory activity were investigated in an in vitro system of peripheral blood PMNs and a human HNSCC cell line (FaDu). HNSCC tissue exhibited considerable infiltration by PMNs, and strong infiltration was associated with poorer survival in advanced disease. PMN count, neutrophil-to-lymphocyte ratio and serum concentrations of CXCL8 (interleukin-8), CCL4 (MIP-1β) and CCL5 (RANTES) were significantly higher in the peripheral blood of HNSCC patients than in that of controls. In vitro, HNSCC-conditioned medium inhibited apoptosis of PMNs, increased chemokinesis and chemotaxis of PMNs, induced release of lactoferrin and matrix metalloproteinase 9 by PMNs and enhanced the secretion of CCL4 by PMN. Our findings demonstrate alterations in PMN biology in HNSCC patients. In vitro, tumor-derived factors modulate cellular functions of PMNs and increase their inflammatory activity. Thus, the interaction between HNSCC and PMNs may contribute to host-mediated changes in the tumor microenvironment.

Withaferin A inhibits breast cancer invasion and metastasis at sub‐cytotoxic doses by inducing vimentin disassembly and serine 56 phosphorylation

Abstract: Withaferin A (WFA) is purified from the plant Withania somnifera and inhibits the vimentin cytoskeleton. Vimentin overexpression in cancer correlates with metastatic disease, induction of epithelial to mesenchymal transition and reduced patient survival. As vimentin functions in cell motility, we wanted to test the hypothesis that WFA inhibits cancer metastasis by disrupting vimentin function. These data showed that WFA had weak cytotoxic and apoptotic activity at concentrations less than or equal to 500 nM, but retained potent anti-invasive activity at these low doses. Imaging of breast cancer cell lines revealed that WFA induces perinuclear vimentin accumulation followed by rapid vimentin depolymerization. A concomitant induction of vimentin ser56 phosphorylation was observed, which is consistent with vimentin disassembly. Structure activity relationships were established using a set of chemically modified WFA analogs and showed that the predicted vimentin-binding region of WFA is necessary to induce vimentin ser56 phosphorylation and for its anti-invasive activity. Pharmacokinetic studies in mice revealed that WFA reaches peak concentrations up to 2 μM in plasma with a half-life of 1.36 hr following a single 4 mg/kg dose. In a breast cancer metastasis mouse model, WFA showed dose-dependent inhibition of metastatic lung nodules and induced vimentin ser56 phosphorylation, with minimal toxicity to lung tissue. Based upon these studies, we conclude that WFA is a potent breast cancer anti-metastatic agent and the anti-metastatic activity of WFA is, at least in part, mediated through its effects on vimentin and vimentin ser56 phosphorylation.

Sex disparities in colorectal cancer incidence by anatomic subsite, race and age†

Abstract: Although incidence of colorectal cancer (CRC) in the United States has declined in recent years, rates remain higher in men than in women and the male-to-female incidence rate ratio (MF IRR) increases progressively across the colon from the cecum to the rectum. Rates among races/ethnicities other than Whites or Blacks have not been frequently reported. To examine CRC rates by sex across anatomic subsite, age and racial/ethnic groups, we used the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program for cases diagnosed among residents of 13 registries during 1992-2006. Incidence rates were expressed per 100,000 person-years and age-adjusted to the 2000 US Standard Population; MF IRR and 95% confidence intervals were also calculated. Among each racial/ethnic group, the MF IRR increased fairly monotonically from close to unity for cecal cancers to 1.81 (Hispanics) for rectal cancers. MF IRRs increased with age most rapidly for distal colon cancers from <1.0 at ages <50 years to 1.4-1.9 at older ages. The MF IRR for rectal cancers also rose with age from about 1.0 to 2.0. For proximal cancer, the MF IRR was consistently <1.5; among American Indian/Alaska Natives, it was <1.0 across all ages. The MF IRRs for CRC vary markedly according to subsite and age but less by racial/ethnic group. These findings may partially reflect differences in screening experiences and access to medical care but also suggest that etiologic factors may be playing a role.

Gene expression profiling reveals novel biomarkers in nonsmall cell lung cancer

Abstract: The development of reliable gene expression profiling technology is having an increasing impact on our understanding of lung cancer biology Our study aimed to determine any correlation between the phenotypic heterogeneity and genetic diversity of lung cancer Microarray analysis was performed on a set of 46 tumor samples and 45 paired nontumor samples of nonsmall cell lung cancer (NSCLC) samples to establish gene signatures in primary adenocarcinomas and squamous-cell carcinomas, determine differentially expressed gene sequences at different stages of the disease and identify sequences with biological significance for tumor progression After the microarray analysis, the expression level of 92 selected genes was validated by qPCR and the robust Bonferroni test in an independent set of 70 samples composed of 48 tumor samples and 22 nontumor samples Gene sequences were differentially expressed as a function of tumor type, stage and differentiation grade High upregulation was observed for KRT15 and PKP1, which may be good markers to distinguish squamous-cell carcinoma samples High downregulation was observed for DSG3 in stage IA adenocarcinomas

G-protein-coupled receptor for short-chain fatty acids suppresses colon cancer.

Abstract: GPR43 is a G-protein-coupled receptor for short-chain fatty acids (SCFAs). Expression of GPR43 is detected in hematopoietic tissues and the large intestine. SCFAs are derived from bacterial fermentation and metabolism of undigested dietary fibers and have been recognized for their cancer prevention activities in the colon. The role of SCFAs, particularly butyrate, in colon cancer therapy has been extensively studied, and its tumor suppressive functions are believed to be due to their intracellular actions, notably inhibition of histone deacetylase. In our study, we show that SCFAs also exert their antitumor effects via receptor GPR43 and that GPR43 is frequently lost in colon cancer cells. Immunohistostaining revealed that GPR43 immunoreactivity was high in normal colon tissues (N = 31) but was markedly reduced or completely lost in most colorectal adenocarcinoma tissues (N = 70) and their corresponding lymph node metastatic adenocarcinomas (N = 38). RT-PCR analysis detected the presence of full length GPR43 mRNA in only one (HT-29) of nine established human colon cancer cell lines. Restoration of GPR43 expression in HCT8 human colonic adenocarcinoma cells induced G0/G1 cell cycle arrest and activated caspases, leading to increased apoptotic cell death after propionate/butyrate treatment. Restored GPR43 expression, coupled with propionate treatment, induced an upregulation of p21 and a decrease in the levels of cyclin D3 and cyclin-dependent kinases (CDKs) 1 and 2, while the CDK4 and CDK6 levels remained unchanged. Our results suggest that GPR43 functions as a tumor suppressor by mediating SCFA-induced cell proliferation inhibition and apoptotic cell death in colon cancer.

Risk of cancer in a large cohort of U.S. veterans with diabetes.

Abstract: Prior studies of cancer risk among diabetic men have reported inconsistent findings. The aim of the current investigation was to assess the risk of cancer among a large cohort (n=4,501,578) of black and white U.S. veterans admitted to Veterans Affairs hospitals. The cancer risk among men with diabetes (n=594,815) was compared to the risk among men without diabetes (n=3,906,763). Poisson regression was used to estimate adjusted relative risks (RRs) and 95% confidence intervals (CIs). Overall, men with diabetes had a significantly lower risk of cancer (RR=0.93, 95%CI=0.93-0.94). Men with diabetes, however, had increased risks of cancers of the liver (RR=1.95, 95%CI=1.82-20.9), pancreas (RR=1.50, 95%CI=1.42-1.59), biliary tract (RR=1.41, 95%CI=1.22-1.62), colon (RR=1.20, 95%CI=1.16-1.25), rectum (RR=1.12, 95%CI=1.07-1.18), and kidney (RR=1.09, 95%CI=1.03-1.16), as well as leukemia (RR=1.14, 95%CI=1.08-1.21) and melanoma (RR=1.13, 95%CI=1.03-1.24). In contrast, men with diabetes had decreased risks of cancers of the prostate (RR=0.89, 95%CI=0.87-0.91), brain (RR=0.91, 95%CI=0.81-0.99), buccal cavity (RR=0.85, 95%CI=0.82-0.89), lung (RR=0.79, 95%CI=0.77-0.80), esophagus (RR=0.77, 95%CI=.072-0.82), and larynx (RR=0.76, 95%CI=0.71-0.80). These findings indicate that black and white men with diabetes are at significantly lower risk of total cancer and of two of the most common cancers among U.S. males; lung and prostate cancers. These decreased risks were offset, however, by increased risks of cancer at several sites. Hyperinsulinemia may explain the increased risks of the digestive cancers, while lower testosterone levels, in the case of prostate cancer, and higher BMI, in the case of lung cancer, may explain the decreased risks of those tumors.

Trends in head and neck cancer incidence in denmark, 1978-2007: focus on human papillomavirus associated sites

Abstract: The aim of our study was to assess the overall trends in the incidence of head-and-neck cancer (HNC) among Danish men and women in 1978-2007, to describe the distribution and incidences of HNCs at different anatomical sites, and to determine whether the incidence of human papillomavirus (HPV)-associated cancers is increasing. Data were extracted from the nationwide Cancer Registry database. To assess the possible impact of HPV infection, the sites of squamous cell carcinomas were categorized as HPV-associated, potentially HPV-associated or HPV-unrelated. In total, 26,474 incident cases were identified and the overall incidence increased throughout the period. Significantly increasing incidence rates were notably seen for tumors in the oral cavity (2.2% per year), tonsils (4.8% per year), oropharynx (3.5% per year) and hypopharynx (4.4% per year). A significantly decreasing incidence of lip cancer was observed among men (-5.0% per year). Cancers at HPV-associated sites (n = 3650) showed strongly increasing incidence rates, primarily in individuals < 60 years. In contrast, HNCs at sites not related to HPV infection showed a significant decrease (in men) or virtually no change in incidence (in women). Our results suggest a marked impact of HPV infection on the epidemiology of HNCs in Denmark. HPV16 is the type most often found in HNCs; thus, the recent introduction of vaccination against HPV may in the future prevent HPV-associated cancers of the head and neck.

Multiple uses of basement membrane‐like matrix (BME/Matrigel) in vitro and in vivo with cancer cells

Abstract: Significant advances in our understanding of cancer cell behavior, growth, and metastasis have been facilitated by studies using a basement membrane-like extracellular matrix extract, also known as Matrigel. The basement membrane is a thin extracellular matrix that is found in normal tissues and contacts epithelial and endothelial cells, smooth muscle, fat, Schwann cells, etc. It is composed of mainly laminin-111, collagen IV, heparan sulfate proteoglycan, entactin/nidogen, and various growth factors (fibroblast growth factor, transforming growth factor beta, epidermal growth factor, etc.). Most tumors of epithelial origin produce significant amounts of basement membrane matrix and interact with it particularly during metastasis. Cancer cells metastasize via degradation of the vessel basement membrane matrix to extravasate into the blood stream and colonize distant sites. This review will focus on the interaction of cancer cells and cancer stem cells with the basement membrane-like matrix and the various uses of this interaction to accelerate tumor growth in vivo and to develop in vitro assays for invasion, morphology, and dormancy. Such assays and methods have advanced our understanding of the process of cancer progression, the genes and pathways that are involved, the potential of various therapeutic agents, the effects of neighboring cells, and the role of stem cells.

Phenotypic Plasticity and Epithelial-Mesenchymal Transitions in Cancer - and Normal Stem Cells?

Abstract: Cancer stem cells (CSCs) are similar to normal stem cells in their ability to self-renew and to generate large populations of more differentiated descendants. In contrast to the hierarchical organization that is presumed to be the prevalent mode of normal tissue homeostasis, phenotypic plasticity allows cancer cells to dynamically enter into and exit from stem-cell states. The epithelial-mesenchymal transition (EMT) has been closely associated with the acquisition of both invasive and stem-cell properties in cancer cells. Thereby, EMT programs emerge as important regulators of phenotypic plasticity in cancer cells including their entrance into stem-cell states. Much is still to be learned about the regulation of EMTs through epigenetic mechanisms in cancer cells and the contributions that EMT programs make to normal tissue homeostasis.

A biparatopic anti-EGFR nanobody efficiently inhibits solid tumour growth

Abstract: The epidermal growth factor receptor (EGFR) has been shown to be a valid cancer target for antibody-based therapy. At present, several anti-EGFR monoclonal antibodies have been successfully used, such as cetuximab and matuzumab. X-ray crystallography data show that these antibodies bind to different epitopes on the ecto-domain of EGFR, providing a rationale for the combined use of these two antibody specificities. We have previously reported on the successful isolation of antagonistic anti-EGFR nanobodies. In our study, we aimed to improve the efficacy of these molecules by combining nanobodies with specificities similar to both cetuximab and matuzumab into a single biparatopic molecule. Carefully designed phage nanobody selections resulted in two sets of nanobodies that specifically blocked the binding of either matuzumab or cetuximab to EGFR and that did not compete for each others' binding. A combination of nanobodies from both epitope groups into the biparatopic nanobody CONAN-1 was shown to block EGFR activation more efficiently than monovalent or bivalent (monospecific) nanobodies. In addition, this biparatopic nanobody potently inhibited EGF-dependent cell proliferation. Importantly, in an in vivo model of athymic mice bearing A431 xenografts, CONAN-1 inhibited tumour outgrowth with an almost similar potency as the whole mAb cetuximab, despite the fact that CONAN-1 is devoid of an Fc portion that could mediate immune effector functions. Compared to therapy using bivalent, monospecific nanobodies, CONAN-1 was clearly more potent in tumour growth inhibition. These results show that the rational design of biparatopic nanobody-based anticancer therapeutics may yield potent lead molecules for further development.

Optimizing targeted therapeutic development: Analysis of a colorectal cancer patient population with the BRAFV600E mutation

Abstract: BRAF(V600E) mutations are found in 10% of colorectal cancers (CRCs). The low frequency of this mutation therefore makes it a challenging target for drug development, unless subsets of patients with higher rates of BRAF(V600E) can be defined. Knowledge of the concordance between primary-metastasis pairs and the impact of BRAF(V600E) on outcome would also assist in optimal drug development. We selected primary CRCs from 525 patients (stages I-IV) evenly matched for age ( 70) females with KRAS wild-type right-sided colon cancers (50%) compared to the unselected cohort (10%). BRAF(V600E) was associated with inferior overall survival in metastatic CRC (HR = 2.02; 95% CI 1.26-3.26), particularly evident in patients treated with chemotherapy, and is independent of MSI status. BRAF status was concordant in all primary tumors and matched metastases (79 wild-type pairs and two mutant pairs). Clinicopathological and molecular features can identify CRC patients with a higher prevalence of BRAF(V600E). Patients with BRAF(V600E) wild-type primary tumor do not appear to acquire the mutation in their metastases, and BRAF(V600E) is associated with poorer outcomes in metastatic patients. Our findings are timely and will help inform the rational development of BRAF(V600E) inhibitors in CRC.

Sunbed use during adolescence and early adulthood is associated with increased risk of early-onset melanoma

Abstract: Sunbed use is associated with increased risk of melanoma. Younger people might be more susceptible to the carcinogenic effects of ultraviolet radiation. We investigated the association between sunbed use and risk of early-onset cutaneous malignant melanoma. From the Australian Melanoma Family Study, a multi-centre, population-based, case-control-family study, we analysed data for 604 cases diagnosed between ages 18 and 39 years and 479 controls. Data were collected by interview. Associations were estimated as odds ratios (ORs) using unconditional logistic regression, adjusting for age, sex, city, education, family history, skin colour, usual skin response to sunlight, and sun exposure. Compared with having never used a sunbed, the OR for melanoma associated with ever-use was 1.41 (95% confidence interval (CI) 1.01-1.96), and 2.01 (95% CI 1.22-3.31) for more than 10 lifetime sessions (Ptrend 0.01 with cumulative use). The association was stronger for earlier age at first use (Ptrend 0.02). The association was also stronger for melanoma diagnosed when aged 18-29 years (OR for more than 10 lifetime sessions = 6.57, 95% CI 1.41-30.49) than for melanoma diagnosed when 30-39 years (OR 1.60, 95% CI 0.92-2.77; Pinteraction 0.01). Among those who had ever used a sunbed and were diagnosed between 18-29 years of age, three quarters (76%) of melanomas were attributable to sunbed use. Sunbed use is associated with increased risk of early-onset melanoma, with risk increasing with greater use, an earlier age at first use and for earlier onset disease.