Association of common gene variants in the WNT/β-catenin pathway with colon cancer recurrence. Pharmacogenomics J. 2014;14:142-150. [PMID: 23817222 DOI: 10.1038/tpj.2013.20]

Andrographis-mediated chemosensitization through activation of ferroptosis and suppression of β-catenin/Wnt-signaling pathways in colorectal cancer

Colorectal cancer (CRC) remains one of the leading causes of cancer-related mortality in the USA. As much as 50-60% of CRC patients develop resistance to 5-fluorouracil (5FU)-based chemotherapeutic regimens, attributing the increased overall morbidity and mortality. In view of the growing evidence that active principles in various naturally occurring botanicals can facilitate chemosensitization in cancer cells, herein, we undertook a comprehensive effort in interrogating the activity of one such botanical-andrographis-by analyzing its activity in CRC cell lines [both sensitive and 5FU resistant (5FUR)], a xenograft animal model and patient-derived tumor organoids. We observed that combined treatment with andrographis was synergistic and resulted in a significant and dose-dependent increase in the efficacy of 5FU in HCT116 and SW480 5FUR cells (P < 0.05), reduced clonogenic formation (P < 0.01) and increased rates of caspase-9-mediated apoptosis (P < 0.05). The genomewide expression analysis in cell lines led us to uncover that activation of ferroptosis and suppression of β-catenin/Wnt-signaling pathways were the key mediators for the anti-cancer and chemosensitizing effects of andrographis. Subsequently, we validated our findings in a xenograft animal model, as well as two independent CRC patient-derived organoids-which confirmed that combined treatment with andrographis was significantly more effective than 5FU and andrographis alone and that these effects were in part orchestrated through dysregulated expression of key genes (including HMOX1, GCLC, GCLM and TCF7L2) within the ferroptosis and Wnt-signaling pathways. Collectively, our data highlight that andrographis might offer a safe and inexpensive adjunctive therapeutic option in the management of CRC patients.

Random survival forests identify pathways with polymorphisms predictive of survival in KRAS mutant and KRAS wild-type metastatic colorectal cancer patients

KRAS status serves as a predictive biomarker of response to treatment in metastatic colorectal cancer (mCRC). We hypothesize that complex interactions between multiple pathways contribute to prognostic differences between KRAS wild-type and KRAS mutant patients with mCRC, and aim to identify polymorphisms predictive of clinical outcomes in this subpopulation. Most pathway association studies are limited in assessing gene–gene interactions and are restricted to an individual pathway. In this study, we use a random survival forests (RSF) method for identifying predictive markers of overall survival (OS) and progression-free survival (PFS) in mCRC patients treated with FOLFIRI/bevacizumab. A total of 486 mCRC patients treated with FOLFIRI/bevacizumab from two randomized phase III trials, TRIBE and FIRE-3, were included in the current study. Two RSF approaches were used, namely variable importance and minimal depth. We discovered that Wnt/β-catenin and tumor associated macrophage pathway SNPs are strong predictors of OS and PFS in mCRC patients treated with FOLFIRI/bevacizumab independent of KRAS status, whereas a SNP in the sex-differentiation pathway gene, DMRT1, is strongly predictive of OS and PFS in KRAS mutant mCRC patients. Our results highlight RSF as a useful method for identifying predictive SNPs in multiple pathways.

WNT5B in Physiology and Disease

WNT5B, a member of the WNT family of proteins that is closely related to WNT5A, is required for cell migration, cell proliferation, or cell differentiation in many cell types. WNT5B signals through the non-canonical β-catenin-independent signaling pathway and often functions as an antagonist of canonical WNT signaling. Although WNT5B has a high amino acid identity with WNT5A and is often assumed to have similar activities, WNT5B often exhibits unique expression patterns and functions. Here, we describe the distinct effects and mechanisms of WNT5B on development, bone, adipose tissue, cardiac tissue, the nervous system, the mammary gland, the lung and hematopoietic cells, compared to WNT5A. We also highlight aberrances in non-canonical WNT5B signaling contributing to diseases such as osteoarthritis, osteoporosis, obesity, type 2 diabetes mellitus, neuropathology, and chronic diseases associated with aging, as well as various cancers.

Polymorphisms within Immune Regulatory Pathways Predict Cetuximab Efficacy and Survival in Metastatic Colorectal Cancer Patients

Simple Summary

Cetuximab is an antibody that blocks EGFR signaling and stimulates an immune response against cancer cells. For patients with advanced colorectal cancer, tumor sidedness and RAS mutation status are the primary factors used to select systemic therapy. Additional biomarkers are needed to better predict which patients will benefit from cetuximab-based regimens. The aim of our retrospective study was to assess the predictive and prognostic value of 12 germline single nucleotide polymorphisms in five immune related genes in 924 patients with advanced colorectal cancer undergoing therapy with cetuximab. We identified a CD24 germline genetic variant which independently predicted survival in a discovery cohort and confirmed these findings in a validation cohort. If confirmed in prospective studies, CD24 and other immune related polymorphisms may guide the use of cetuximab in patients with advanced colorectal cancer.

Abstract

Cetuximab, an IgG1 EGFR-directed antibody, promotes antibody-dependent cell-mediated cytotoxicity. We hypothesized that single-nucleotide polymorphisms (SNPs) in immune regulatory pathways may predict outcomes in patients with metastatic colorectal cancer treated with cetuximab-based regimens. A total of 924 patients were included: 105 received cetuximab in IMCL-0144 and cetuximab/irinotecan in GONO-ASL608LIOM01 (training cohort), 225 FOLFIRI/cetuximab in FIRE-3 (validation cohort 1), 74 oxaliplatin/cetuximab regimens in JACCRO CC-05/06 (validation cohort 2), and 520 FOLFIRI/bevacizumab in FIRE-3 and TRIBE (control cohorts). Twelve SNPs in five genes (IDO1; PD-L1; PD-1; CTLA-4; CD24) were evaluated by PCR-based direct sequencing. We analyzed associations between genotype and clinical outcomes. In the training cohort; patients with the CD24 rs52812045 A/A genotype had a significantly shorter median PFS and OS than those with the G/G genotype (PFS 1.3 vs. 3.6 months; OS 2.3 vs. 7.8 months) in univariate (PFS HR 3.62; p = 0.001; OS HR 3.27; p = 0.0004) and multivariate (PFS HR 3.18; p = 0.009; OS HR 4.93; p = 0.001) analyses. Similarly; any A allele carriers in the JACCRO validation cohort had a significantly shorter PFS than G/G carriers (9.2 vs. 11.8 months; univariate HR 1.90; p = 0.011; multivariate HR 2.12; p = 0.018). These associations were not demonstrated in the control cohorts. CD24 genetic variants may help select patients with metastatic colorectal cancer most likely to benefit from cetuximab-based therapy.

GC-Derived EVs Enriched with MicroRNA-675-3p Contribute to the MAPK/PD-L1-Mediated Tumor Immune Escape by Targeting CXXC4

MicroRNAs (miRNAs) delivered by gastric cancer (GC)-secreted extracellular vesicles (GC-EVs) are associated with the immune escape in GC. Microarray analysis based on the GEO: GSE112369 dataset identified the presence of poorly expressed CXXC finger protein 4 (CXXC4) in GC, which was validated in clinical samples of GC patients. Moreover, prediction based on TargetScan analysis demonstrated the putative miR-675-3p binding site in the 3′ UTR region of CXXC4. Thereby, our study aims to determine the role of GC-EV-encapsulated miR-675-3p in GC. First, CXXC4 was found to be negatively correlated with programmed cell death 1 ligand 1 (PD-L1). The effects of mitogen-activated protein kinase (MAPK) signaling on GC were evaluated using activator of the MAPK pathway. The overexpression of CXXC4 led to a downregulated MAPK signaling pathway, thus decreasing PD-L1 expression to augment the proliferation and activation of T cells co-cultured with GC HGC-27 cells. GC-EV-encapsulated miR-675-3p negatively regulated the expression of its target gene CXXC4. GC-EV-encapsulated miR-675-3p increased PD-L1 expression to stimulate the immune escape in vitro and EV-encapsulated miR-675-3p accelerated cisplatin resistance in vivo. Collectively, the aforementioned findings present a mechanism in which EV-mediated miR-675-3p upregulates PD-L1 expression, promoting immune escape in GC.

Emerging Roles of Wnt Ligands in Human Colorectal Cancer

Colorectal cancer (CRC) is the fourth leading cause of cancer death worldwide, and constitutive activation of the Wnt signaling pathway is universal in most CRC cases. Wnt ligands (Wnts) are secreted glycoproteins and fundamentally essential for the transduction of Wnt signaling pathway. However, the 19 members of Wnts in humans imply a daunting complexity of Wnt signaling and biological effects, and our understanding of their roles in CRC tumorigenesis is still quite rudimentary. This review will give an overview of the structural characteristics and maturation process of Wnts. The expression pattern of all human Wnts in CRC tissues, including Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt4, Wnt5a, Wnt5b, Wnt6, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt9a, Wnt9b, Wnt10a, Wnt10b, Wnt11, and Wnt16, and their relationship with the tumorigenesis and the progression of CRC will be specifically summarized separately. Despite certain challenges, Wnt-based therapeutics for CRC emerge continuously and some are now in clinical trials. In conclusion, a deep understanding of Wnts is very helpful for a better management of this disease.

High-order gene interactions between the genetic polymorphisms in Wnt and AhR pathway in modulating lung cancer susceptibility

AIM

Genetic variations present within Wnt and AhR pathway might be related to the lung cancer susceptibility.

METHODS

A total of 555 subjects were genotyped using PCR-RFLP technique for polymorphic sites in DKK4, DKK3, DKK2, sFRP3, sFRP4, Axin2 and AhR. Multifactor dimensionality reduction method and classification and regression tree analysis was used.

RESULTS

Overall sFRP4_rs1802073 which has a cross validation consistency of 10/10, prediction error = 0.43 (p > 0.0001) is the best factor model. The second best model was sFRP4_rs1802073 and DKK2_rs419558 with cross validation consistency of 9/10 and prediction error = 0.40. In classification and regression tree analysis, DKK2 _rs419558 came out to be a significant factor; DKK2_rs17037102 (M)/DKK2_rs419558 (M) showed a tenfold risk of acquiring lung cancer, p = 0.0001. DKK2_rs17037102 (M)/AhR_rs2066853 (W)/AhR_rs10250822 (M) showed an 11-fold risk of developing lung cancer, p = 0.00001.

CONCLUSION

Both DKK2 and sFRP4 polymorphisms are found to play a crucial role; especially for smokers towards modulating risk for lung cancer. AhR variants are contributing maximally toward lung cancer risk.

Association study between genetic variations in Axin2 gene and lung cancer risk in North Indian population: A multiple interaction analysis

Wnt pathway has been implicated in the process of human carcinogenesis. Axis inhibition protein2 ( Axin2), a major scaffold protein is an antagonist of Wnt pathway and is potent to act as a tumor suppressor gene in various human cancers. Therefore, the seven polymorphic sites of Axin2 gene were analyzed, in relation to lung cancer susceptibility in North Indians. A total of 608 subjects were genotyped using PCR-RFLP technique for each polymorphic site including 303 cases and 305 controls. Further association analysis was carried out using logistic regression approach to obtain adjusted odds ratio and statistical significance. MDR and CART analysis were applied to evaluate high order interactions between the SNP's. Three out of seven studied polymorphic sites showed a strong protective effect in subjects having mutant genotype for Axin2 148 C >T and heterozygous genotype for 1365 G > A and 1712 + 19 G > T towards lung cancer risk. The other important finding was the significant association of Axin2 148 C >T in SQCC patients having variant (TT) genotype. Axin2 1712 + 19 G >T showed a decreased risk for all the histological subtypes in patients with heterozygous (GT) genotype. MDR analysis predicted a best interaction model ( Axin2 148, Axin2 2062 and Axin2 1712 +19) with maximum CVC (10/10) and minimum prediction error (0.38) along with significant permutation p-value. CART analysis gave a wide spectrum of interactive combinations which exhibited a major contribution in modulating lung cancer susceptibility. Axin2 148 and Axin2 1712 + 19 were found to play a major role in modulating lung cancer risk.

Chemopreventive Effects of Germinated Rough Rice Crude Extract in Inhibiting Azoxymethane-Induced Aberrant Crypt Foci Formation in Sprague-Dawley Rats

Chemoprevention has become an important area in cancer research due to low success rate of current therapeutic modalities. Diet plays a vital role in the etiology of cancer. This research was carried out to study the chemopreventive properties of germinated rough rice (GRR) crude extract in Sprague-Dawley rats induced with azoxymethane. Germination of rough rice causes significant changes in several chemical compositions of presently bioactive compounds. These compounds may prevent or postpone the inception of cancer. Fifty male Sprague-Dawley rats (6 weeks of age) were randomly divided into 5 groups which were (G1) induced with azoxymethane (AOM) and not given GRR (positive control), (G2) induced with AOM and given 2000 mg/kg GRR, (G3) induced with AOM and given 1000 mg/kg GRR, (G4) induced with AOM and given 500 mg/kg GRR, and (G5) not induced with AOM and not given GRR crude extract (negative control). To induce colon cancer, rats received two IP injections of AOM in saline (15 mg/kg) for two subsequent weeks. Organs were removed and weighed. Aberrant crypt foci (ACF) were evaluated histopathologically. β-Catenin expressions were determined by Western blot. Treatment with 2000 mg/kg GRR crude extract not only resulted in the greatest reduction in the size and number of ACF but also displayed the highest percentage of nondysplastic ACF. Treatment with 2000 mg/kg GRR also gave the lowest level of expression in β-catenin. Thus, GRR could be a promising dietary supplement for prevention of CRC.

Genetic polymorphisms of Wnt/β-catenin pathway genes are associated with the efficacy and toxicities of radiotherapy in patients with nasopharyngeal carcinoma

Radiotherapy (RT) is the normative therapeutic treatment for primary nasopharyngeal carcinoma (NPC). Single nucleotide polymorphisms (SNPs) of genes in Wnt/β-catenin pathway are correlated to the development, prognosis, and treatment benefit of various cancers. However, it has not been established whether SNPs of Wnt/β-catenin pathway are associated with nasopharyngeal tumorigenesis and the efficacy of RT in NPC patients. Therefore, in this study, we aimed to investigate the nine potentially functional SNPs of four genes in the Wnt/β-catenin pathway and genotyped these in 188 NPC patients treated with RT. To achieve this goal, associations between these SNPs and the RT's curative efficacy, as well as acute radiation-induced toxic reaction were determined by multifactorial logistic regression. We observed that catenin beta 1 gene (CTNNB1) rs1880481 and rs3864004, and glycogen synthase kinase 3 beta gene (GSK3β) rs3755557 polymorphisms were significantly associated with poorer efficacy of RT in NPC patients. Moreover, GSK3β rs375557 and adenomatous polyposis coli gene (APC) rs454886 polymorphisms were correlated with acute grade 3-4 radiation-induced dermatitis and oral mucositis, respectively. In conclusion, this study suggests that gene polymorphisms of Wnt/β-catenin may be novel prognostic factors for NPC patients treated with RT.

Association of polymorphisms in Dickopff (DKK) gene towards modulating risk for lung cancer in north Indians

AIM

To investigate the association between the genetic variants of DKK4 (rs2073664), DKK3 (rs2291599, rs3206824 and rs7391689) and DKK2 (rs447372, rs419558 and rs17037102) and lung cancer predisposition in north Indians.

MATERIALS & METHODS

A total of 600 subjects were genotyped using PCR restriction fragment length polymorphism technique. Association analysis was carried out using logistic regression approach.

RESULTS

DKK3 rs7396187 showed a protective effect (p = 0.01). Subjects with heterozygous genotype of DKK2 rs17037102 and rs419558 showed an increased risk. The variant genotype of the genotypic combination, DKK3 rs3206824 and DKK2 rs419558 showed a twofold increased risk (p = 0.008). Lung cancer risk increased four-times in subjects with variant genotype of all the three DKK2 variants.

CONCLUSION

DKK2 is certainly playing a crucial role in modulating cancer susceptibility.

Carbonic anhydrase IV inhibits colon cancer development by inhibiting the Wnt signalling pathway through targeting the WTAP-WT1-TBL1 axis

OBJECTIVE

We found that carbonic anhydrase IV (CA4), a member of the carbonic anhydrases, is silenced in colorectal cancer (CRC). We analysed its epigenetic inactivation, biological effects and prognostic significance in CRC.

DESIGN

The biological functions of CA4 were determined by in vitro and in vivo tumorigenicity assays. The CA4 co-operator was identified by immunoprecipitation and mass spectrometry. CA4 downstream effectors and signalling pathways were elucidated by promoter luciferase assay, electrophoretic mobility shift assay and chromatin immunoprecipitation. The clinical impact of CA4 was assessed in 115 patients with CRC.

RESULTS

CA4 was silenced in all nine CRC cell lines and 92.6% of CRC tumours. The promoter hypermethylation contributed to the inactivation of CA4, and it was detected in 75.7% of the patients with CRC. After a median follow-up of 49.3 months, multivariate analysis showed that the patients with CA4 hypermethylation had a recurrence of Stage II/III CRC. The re-expression of CA4 inhibited cell proliferation, induced apoptosis and cell cycle arrest in the G1 phase. CA4 inhibited the activity of the Wnt signalling pathway and mediated the degradation of β-catenin. CA4 interacted with Wilms' tumour 1-associating protein (WTAP) and induced WTAP protein degradation through polyubiquitination. Moreover, CA4 promoted the transcriptional activity of Wilms' tumour 1 (WT1), an antagonist of the Wnt pathway, which resulted in the induction of transducin β-like protein 1 (TBL1) and the degradation of β-catenin.

CONCLUSIONS

CA4 is a novel tumour suppressor in CRC through the inhibition of the Wnt signalling pathway by targeting the WTAP-WT1-TBL1 axis. CA4 methylation may serve as an independent biomarker for the recurrence of CRC.

TCF7L2 rs7903146 polymorphism is associated with gastric cancer: A case-control study in the Venezuelan population

AIM

To explore the association between TCF7L2 rs12255372 and rs7903146 single nucleotide polymorphisms (SNPs) and gastric cancer risk in Venezuelan patients.

METHODS

We performed a case-control study including 122 paraffin-embedded archived intestinal-type gastric cancer samples and 129 biopsies obtained by superior endoscopy from chronic gastritis patients. Gastric cancer samples were classified according the degree of carcinoma differentiation. Genomic DNA was extracted from tissues, and the two SNPs of TCF7L2 gene (rs12255372 and rs7903146) were genotyped by polymerase chain reaction-restriction fragment length polymorphism reactions. Multiple regression analysis with adjustments for age and gender were performed and best-fitting models of inheritance were determined. Statistic powers were post-hoc calculated.

RESULTS

After adjusting for age and sex the TCF7L2 rs7903146 TT genotype was associated with gastric cancer risk under the recessive genetic model (OR = 3.11, 95%CI: 1.22-7.92, P = 0.017). We further investigated the distribution of rs12255372 and rs7903146 genotypes according gastric cancer stratified by degree of differentiation, and we observed that carriers of rs7903146 T allele (CT + TT vs CC) had a significantly increased risk of moderate/well differentiated gastric cancer (dominant model, OR = 2.55, 95%CI: 1.35-4.80, P = 0.004), whereas the rs7903146 TT genotype was associated with poorly differentiated gastric cancer in the recessive model (OR = 3.65, 95%CI: 1.25-10.62, P = 0.018). We did not find association between rs12255372 SNP and the susceptibility of developing gastric cancer.

CONCLUSION

TCF7L2 rs7903146 polymorphism is associated with gastric cancer risk in the Venezuelan population, and could be related to determine the degree of differentiation of tumor cells.

Overexpression of WNT5B promotes COLO 205 cell migration and invasion through the JNK signaling pathway

WNT5B is a member of the WNT family that has been reported to be overexpressed in a variety of cancer cell lines and tissues, including colorectal cancer (CRC). However, the potential roles of WNT5B in tumorigenesis have not been reported. In the present study, the WNT5B gene was transfected into CRC cells and generated a COLO 205 cell line with stable overexpression of WNT5B. MTT, wound healing and Transwell assays showed that overexpression of WNT5B significantly increased cell proliferation, migration and invasion capacities of the COLO 205 cells in vitro. Meanwhile, western blotting demonstrated that cells with stable expression of WNT5B showed increased protein expression levels and activities of matrix metalloproteinase (MMP) 2 and MMP 9. In addition, we also observed activation of the WNT/JNK signaling pathway in WNT5B-overexpressing cells. Subsequently, c-jun NH2-terminal kinase (JNK) was knocked down by RNA interference in the WNT5B-overexpressing COLO 205 cells. Knockdown of JNK significantly reduced the migratory capacity of the COLO 205 cells and decreased protein expression levels and activities of MMP 2 and 9 in vitro. In conclusion, our findings suggest that WNT5B may play an important role in the tumorigenesis of CRC.

The Prognostic Significance of the Hedgehog Signaling Pathway in Colorectal Cancer

Despite significant advances in the management of colorectal cancer (CRC) the identification of new prognostic biomarkers continues to be a challenge. Since its initial discovery, the role of the Hedgehog (Hh) signaling pathway in carcinogenesis has been extensively studied. We herein review and comment on the prognostic significance of the Hh signaling pathway in CRC. The differential expression of Hh pathway components between malignant and nonmalignant conditions as well as correlation of Hh activation markers with various clinicopathological parameters and the effect on disease-free survival, overall survival, and disease recurrence in patients with CRC is summarized and discussed. According to the studies reviewed herein the activation of the Hh pathway seems to be correlated with adverse clinicopathological features and worse survival. However, to date study results show significant variability with regard to the effect on outcomes. Such results need to be interpreted carefully and emphasize the need for further well designed studies to characterize the actual influence of the Hh pathway in CRC prognosis.

Single Nucleotide Polymorphisms as Prognostic and Predictive Factors of Adjuvant Chemotherapy in Colorectal Cancer of Stages I and II

Colorectal cancer (CRC) is a highly heterogeneous disease regarding the stage at time of diagnosis and there is special attention regarding adjuvant chemotherapy in unselected patients with stage I and stage II. The clinicohistologically based TNM staging system with emphasis on histological evaluation of primary tumor and resected regional lymph nodes remains the standard of staging, but it has restricted sensitivity resulting in false downward stage migration. Molecular characteristics might predispose tumors to a worse prognosis and identification of those enables identifying patients with high risk of disease recurrence. Suitable predictive markers also enable choosing the most appropriate therapy. The current challenge facing adjuvant chemotherapy in stages I and II CRC is choosing patients with the highest risk of disease recurrence who are going to derive most benefit without facing unnecessary adverse effects. Single nucleotide polymorphisms (SNPs) are one of the potential molecular markers that might help us identify patients with unfavorable prognostic factors regarding disease initiation and recurrence and could determine selection of an appropriate chemotherapy regimen in the adjuvant and metastatic setting. In this paper, we discuss SNPs of genes involved in the multistep processes of cancerogenesis, metastasis, and the metabolism of chemotherapy that might prove clinically significant.

Association of Wnt signaling pathway genetic variants in gallbladder cancer susceptibility and survival

Gallbladder cancer (GBC) is the most common malignancy of the biliary tract with adverse prognosis and poor survival. Wnt signaling plays an important role in embryonic development and regeneration of tissues in all the species. Deregulation of expression and mutations in this pathway may lead to disease state such as cancer. In this study, we assessed the association of common germline variants of Wnt pathway genes (SFRP2, SFRP4, DKK2, DKK3, WISP3, APC, β-catenin, AXIN-2, GLI-1) to evaluate their contribution in predisposition to GBC and treatment outcomes. The study included 564 GBC patients and 250 controls. Out of 564, 200 patients were followed up for treatment response and survival. Tumor response (RECIST 1.1) was recorded in 116 patients undergoing non-adjuvant chemotherapy (NACT). Survival was assessed by Kaplan-Meier curve and Cox-proportional hazard regression. Single locus analysis showed significant association of SFRP4 rs1802073G > T [p value = 0.0001], DKK2 rs17037102C > T [p value = 0.0001], DKK3 rs3206824C > T [p value = 0.012], APC rs4595552 A/T [p value = 0.021], APC rs11954856G > T [p value = 0.047], AXIN-2 rs4791171C > T [p value = 0.001], β-catenin rs4135385A > G [p value = 0.031], and GLI-1 rs222826C > G [p value = 0.001] with increased risk of GBC. Gene-gene interaction using GMDR analysis predicted APC rs11954856 and AXIN2 rs4791171 as significant in conferring GBC susceptibility. Cox-proportional hazard model showed GLI-1 rs2228226 CG/GG and AXIN-2 rs4791171 TT genotype higher hazard ratio. In recursive partitioning, AXIN-2 rs4791171 TT genotype showed higher mortality and hazard. Most of studied genetic variants influence GBC susceptibility. APC rs11954856, GLI-1 rs2228226, and AXIN-2 rs4791171 were found to be associated with poor survival in advanced GBC patients.

Functions of TET Proteins in Hematopoietic Transformation

DNA methylation is a well-characterized epigenetic modification that plays central roles in mammalian development, genomic imprinting, X-chromosome inactivation and silencing of retrotransposon elements. Aberrant DNA methylation pattern is a characteristic feature of cancers and associated with abnormal expression of oncogenes, tumor suppressor genes or repair genes. Ten-eleven-translocation (TET) proteins are recently characterized dioxygenases that catalyze progressive oxidation of 5-methylcytosine to produce 5-hydroxymethylcytosine and further oxidized derivatives. These oxidized methylcytosines not only potentiate DNA demethylation but also behave as independent epigenetic modifications per se. The expression or activity of TET proteins and DNA hydroxymethylation are highly dysregulated in a wide range of cancers including hematologic and non-hematologic malignancies, and accumulating evidence points TET proteins as a novel tumor suppressor in cancers. Here we review DNA demethylation-dependent and -independent functions of TET proteins. We also describe diverse TET loss-of-function mutations that are recurrently found in myeloid and lymphoid malignancies and their potential roles in hematopoietic transformation. We discuss consequences of the deficiency of individual Tet genes and potential compensation between different Tet members in mice. Possible mechanisms underlying facilitated oncogenic transformation of TET-deficient hematopoietic cells are also described. Lastly, we address non-mutational mechanisms that lead to suppression or inactivation of TET proteins in cancers. Strategies to restore normal 5mC oxidation status in cancers by targeting TET proteins may provide new avenues to expedite the development of promising anti-cancer agents.

Type 2 diabetes-related variants influence the risk of developing multiple myeloma: results from the IMMEnSE consortium

Type 2 diabetes (T2D) has been suggested to be a risk factor for multiple myeloma (MM), but the relationship between the two traits is still not well understood. The aims of this study were to evaluate whether 58 genome-wide-association-studies (GWAS)-identified common variants for T2D influence the risk of developing MM and to determine whether predictive models built with these variants might help to predict the disease risk. We conducted a case-control study including 1420 MM patients and 1858 controls ascertained through the International Multiple Myeloma (IMMEnSE) consortium. Subjects carrying the KCNQ1rs2237892T allele or the CDKN2A-2Brs2383208G/G, IGF1rs35767T/T and MADDrs7944584T/T genotypes had a significantly increased risk of MM (odds ratio (OR)=1.32-2.13) whereas those carrying the KCNJ11rs5215C, KCNJ11rs5219T and THADArs7578597C alleles or the FTOrs8050136A/A and LTArs1041981C/C genotypes showed a significantly decreased risk of developing the disease (OR=0.76-0.85). Interestingly, a prediction model including those T2D-related variants associated with the risk of MM showed a significantly improved discriminatory ability to predict the disease when compared to a model without genetic information (area under the curve (AUC)=0.645 vs AUC=0.629; P=4.05×10(-) (06)). A gender-stratified analysis also revealed a significant gender effect modification for ADAM30rs2641348 and NOTCH2rs10923931 variants (Pinteraction=0.001 and 0.0004, respectively). Men carrying the ADAM30rs2641348C and NOTCH2rs10923931T alleles had a significantly decreased risk of MM whereas an opposite but not significant effect was observed in women (ORM=0.71 and ORM=0.66 vs ORW=1.22 and ORW=1.15, respectively). These results suggest that TD2-related variants may influence the risk of developing MM and their genotyping might help to improve MM risk prediction models.

Genetic markers of recurrence in colorectal cancer

Colorectal cancer (CRC) worldwide belongs to one of the most frequent cancers affecting both genders. Surgery and 5-fluorouracil-based adjuvant chemotherapy are recommended for patients with high-risk stage II and stage III colon carcinoma. Mutations of genes encoding for specific proteins may have an impact on the time to recurrence. These proteins act over specific signaling pathways, are implicated in metabolic processes and regulate the cell cycle. Though many retrospective studies show strong associations between genetic mutations and the clinical outcome of patients with CRC, currently no validated biomarkers are used in clinical routine settings. Therefore, large prospective validation studies should be carried out in order to strengthen the position of genetic mutations in personalized treatment of patients with CRC.

The role of IGFBP-5 in mediating the anti-proliferation effect of tetrandrine in human colon cancer cells

Colon cancer is one of the most common malignancies, causes considerable morbidity and mortality. The current treatment for colon cancer is more modest than had been hoped. There is an urgent clinical need to explore new agents or adjuvants for colon cancer treatment. Natural products and their derivates act as one of the major source for anticancer agent. In the present study, we investigated the anti-proliferation and chemoprevention effects of tetrandrine (Tet) on colon cancer cells to uncover the possible molecular basis of this effect. We found that Tet can inhibit proliferation and induce apoptosis in LoVo cells. With dimethylhydrazine (DMH) and dextran sodium sulfate (DSS) induced colon cancer model, we found that Tet can prevent or inhibit DMH plus DSS induced aberrant crypt foci (ACF) and colon cancer formation, as well as suppress tumor growth in the xenograft colon cancer model. Tet can downregulate the expression of IGFBP-5 in LoVo cells. Exogenous expression of IGFBP-5 can attenuate the anti-cancer activity of Tet, while IGFBP-5 knockdown potentiates this effect of Tet on LoVo cells. Tet can inhibit Wnt/β-catenin signaling transduction, which can be partly reversed by exogenous expression of IGFBP-5, but is enhanced by IGFBP-5 knockdown. Our results demonstrated that the anticancer activity of Tet in colon cancer cells may be mediated partly by downregulating the expression of IGFBP-5, thus inactivating Wnt/β-catenin signaling transduction.

Connections between TET proteins and aberrant DNA modification in cancer

DNA methylation has been linked to aberrant silencing of tumor suppressor genes in cancer, and an imbalance in DNA methylation-demethylation cycles is intimately implicated in the onset and progression of tumors. Ten-eleven translocation (TET) proteins are Fe(II)- and 2-oxoglutarate (2OG)-dependent dioxygenases that successively oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC), thereby mediating active DNA demethylation. In this review, we focus on the pathophysiological role of TET proteins and 5hmC in cancer. We present an overview of loss-of-function mutations and abnormal expression and regulation of TET proteins in hematological malignancies and solid tumors, and discuss the potential prognostic value of assessing TET mutations and 5hmC levels in cancer patients. We also address the crosstalk between TET and two critical enzymes involved in cell metabolism: O-linked β-N-acetylglucosamine transferase (OGT) and isocitrate dehydrogenase (IDH). Lastly, we discuss the therapeutic potential of targeting TET proteins and aberrant DNA methylation in cancer.

Genes involved in pericyte-driven tumor maturation predict treatment benefit of first-line FOLFIRI plus bevacizumab in patients with metastatic colorectal cancer

Pericytes are crucial for angiogenesis. The impact of pericyte function to bevacizumab efficacy in mCRC treatment has not been comprehensively examined. This retrospective study investigated germline polymorphisms in genes related to early pericyte maturation to predict bevacizumab efficacy in 424 patients of two clinical trials treated first line with FOLFIRI+bevacizumab. Eight single-nucleotide polymorphisms (SNPs) were tested for potential biomarker value: RGS5 (regulator of G-protein signaling 5; rs1056515, rs2661280), PDGFR-β (platelet-derived growth factor receptor-β; rs2229562, rs2302273), CSPG4 (chondroitin sulfate proteoglycan NG2; rs8023621, rs1127648) and RALBP1 (RalA binding protein 1; rs10989, rs329007). For progression-free survival (PFS), PDGFR-β (rs2302273) was able to define significantly different patient cohorts in uni- and multivariate testing. RALPB1 (rs329007) showed predictive value for tumor response. The C allele in RGS5 (rs2661280) predicted longer overall survival and CSPG4 rs1127648 was associated with differences in PFS, but for both value was lost when multivariate analysis was applied. A comprehensive statistical analysis revealed that the biomarker value of the SNPs was dependent on primary tumor location. This is the first study to identify pericyte germline polymorphisms associated with clinical outcome in mCRC patients treated first line with FOLFIRI+bevacizumab. The differences seen with regard to primary tumor location may lead to further research to understand the clinical outcome differences seen in right- and left-sided colon cancer.

Interference of mucin 1 inhibits progression of colon carcinoma by repression of Wnt/β-catenin signaling

Mucin 1 (Muc1) is a tumor-associated glycoprotein and has an important role in cancer progression and metastasis. The aim of the study was to explore the effects and mechanism of Muc1 silencing on proliferation and tumor-forming capacity of colon cancer cell lines. In the present study, we first screened the colon cancer cell lines with high expression of Muc1 by western blot analysis. Then, the effective siRNA was selected and used for silencing endogenous Muc1. The results by MTT and vitro scratch assay showed that interference of Muc1 could effectively inhibit HCC2998 proliferation and migration (p<0.01). Also, colony-forming ability in Muc1-siRNA groups was significantly decreased compared with the control group (p<0.01). Cell cycle is detected by flow cytometry that suggested that Muc1-siRNA1 induced cell cycle arrest at S phase in HCC2998. Next, the expression and distribution of β-catenin in cytoplasm and the nucleus was detected by western blot and the results revealed that the expression of β-catenin was redistributed in Muc1-siRNA group. A higher β-catenin level was detected in cytoplasm, while a lower β-catenin level was located in nucleus, compared with controls (p<0.05). The tumorigenicity experiments showed that inhibition of Muc1 could significantly suppress the growth of HCC2998 in nude mice models (p<0.01). This study would effectively provide new clues for colon cancer therapy.