Deregulation of MYC and TP53 through genetic and epigenetic alterations in gallbladder carcinomas

Gallbladder Cancer: Current Multimodality Treatment Concepts and Future Directions

Gallbladder cancer (GBC) is the most common primary tumor site of biliary tract cancer (BTC), accounting for 0.6% of newly diagnosed cancers and 0.9% of cancer-related deaths. Risk factors, including female sex, age, ethnic background, and chronic inflammation of the gallbladder, have been identified. Surgery is the only curative option for early-stage GBC, but only 10% of patients are primary eligible for curative treatment. After neoadjuvant treatment, up to one-third of locally advanced GBC patients could benefit from secondary surgical treatment. After surgery, only a high-risk subset of patients benefits from adjuvant treatment. For advanced-stage GBC, palliative chemotherapy with gemcitabine and cisplatin is the current standard of care in line with other BTCs. After the failure of gemcitabine and cisplatin, data for second-line treatment in non-resectable GBC is poor, and the only recommended chemotherapy regimen is FOLFOX (5-FU/folinic acid and oxaliplatin). Recent advances with the PD-L1 inhibitor durvalumab open the therapy landscape for immune checkpoint inhibition in GBC. Meanwhile, targeted therapy approaches are a cornerstone of GBC therapy based on molecular profiling and new evidence of molecular differences between different BTC forms and might further improve the prognosis of GBC patients.

MethylSPWNet and MethylCapsNet: Biologically Motivated Organization of DNAm Neural Networks, Inspired by Capsule Networks

DNA methylation (DNAm) alterations have been heavily implicated in carcinogenesis and the pathophysiology of diseases through upstream regulation of gene expression. DNAm deep-learning approaches are able to capture features associated with aging, cell type, and disease progression, but lack incorporation of prior biological knowledge. Here, we present modular, user-friendly deep-learning methodology and software, MethylCapsNet and MethylSPWNet, that group CpGs into biologically relevant capsules-such as gene promoter context, CpG island relationship, or user-defined groupings-and relate them to diagnostic and prognostic outcomes. We demonstrate these models' utility on 3,897 individuals in the classification of central nervous system (CNS) tumors. MethylCapsNet and MethylSPWNet provide an opportunity to increase DNAm deep-learning analyses' interpretability by enabling a flexible organization of DNAm data into biologically relevant capsules.

Long noncoding RNA HNF1A-AS1 regulates proliferation and apoptosis of glioma through activation of the JNK signaling pathway via miR-363-3p/MAP2K4

Long noncoding RNAs (lncRNAs) have been proven to exert important functions in the various biological processes of human cancers. It has been reported that lncRNA HNF1 homeobox A antisense RNA 1 (HNF1A-AS1) was abnormally expressed and played a role in the initiation and development of various human cancers. In this study, we confirmed that the expression level of HNF1A-AS1 was increased in glioma tissues and cells. Knockdown of HNF1A-AS1 inhibited cell proliferation and promoted cell apoptosis in glioma. Then, we disclosed the downregulation of miR-363-3p in glioma tissues and cell lines. The interaction between HNF1A-AS1 and miR-363-3p was identified in glioma cells. Furthermore, an inverse correlation between HNF1A-AS1 and miR-363-3p was observed in glioma tissues. Afterwards, we recognized that MAP2K4 was a direct target of miR-363-3p. The expression of MAP2K4 was negatively correlated with miR-363-3p while positively related to HNF1A-AS1 in glioma tissues. We also found the regulatory effect of HNF1A-AS1 on the MAP2K4-dependent JNK signaling pathway. All findings indicated that HNF1A-AS1 induces the upregulation of MAP2K4 to activate the JNK signaling pathway to promote glioma cell growth by acting as a miR-363-3p sponge.

The Complex Network between MYC Oncogene and microRNAs in Gastric Cancer: An Overview

Despite the advancements in cancer treatments, gastric cancer is still one of the leading causes of death worldwide. In this context, it is of great interest to discover new and more effective ways of treating this disease. Accumulated evidences have demonstrated the amplification of 8q24.21 region in gastric tumors. Furthermore, this is the region where the widely known MYC oncogene and different microRNAs are located. MYC deregulation is key in tumorigenesis in various types of tissues, once it is associated with cell proliferation, survival, and drug resistance. microRNAs are a class of noncoding RNAs that negatively regulate the protein translation, and which deregulation is related with gastric cancer development. However, little is understood about the interactions between microRNAs and MYC. Here, we overview the MYC role and its relationship with the microRNAs network in gastric cancer aiming to identify potential targets useful to be used in clinic, not only as biomarkers, but also as molecules for development of promising therapies.

Comparing the effects of vitamin E tocotrienol-rich fraction supplementation and α-tocopherol supplementation on gene expression in healthy older adults

OBJECTIVES

This study aims to compare the differential gene expression resulting from tocotrienol-rich fraction and α-tocopherol supplementation in healthy older adults.

METHODS

A total of 71 eligible subjects aged 50 to 55 years from Gombak and Kuala Lumpur, Malaysia, were divided into three groups and supplemented with placebo (n=23), α-tocopherol (n=24) or tocotrienol-rich fraction (n=24). Blood samples were collected at baseline and at 3 and 6 months of supplementation for microarray analysis.

RESULTS

The number of genes altered by α-tocopherol was higher after 6 months (1,410) than after 3 months (273) of supplementation. α-Tocopherol altered the expression of more genes in males (952) than in females (731). Similarly, tocotrienol-rich fraction modulated the expression of more genes after 6 months (1,084) than after 3 months (596) and affected more genes in males (899) than in females (781). α-Tocopherol supplementation modulated pathways involving the response to stress and stimuli, the immune response, the response to hypoxia and bacteria, the metabolism of toxins and xenobiotics, mitosis, and synaptic transmission as well as activated the mitogen-activated protein kinase and complement pathways after 6 months. However, tocotrienol-rich fraction supplementation affected pathways such as the signal transduction, apoptosis, nuclear factor kappa B kinase, cascade extracellular signal-regulated kinase-1 and extracellular signal-regulated kinase-2, immune response, response to drug, cell adhesion, multicellular organismal development and G protein signaling pathways.

CONCLUSION

Supplementation with either α-tocopherol or tocotrienol-rich fraction affected the immune and drug response and the cell adhesion and signal transduction pathways but modulated other pathways differently after 6 months of supplementation, with sex-specific responses.

The PLGF/c-MYC/miR-19a axis promotes metastasis and stemness in gallbladder cancer

Gallbladder cancer (GBC) is the most common malignant tumor of the biliary tract system. Epithelial-mesenchymal transition (EMT) plays a vital role in the process of tumor metastasis. Mesenchymal-like cells can serve as a source of cancer stem cells, which can confer the EMT phenotype. Placental growth factor (PLGF) belongs to the vascular endothelial growth factor family and plays a vital role in cancer. However, the underlying molecular mechanisms about the influence of PLGF on EMT in GBC remain unknown. Here we show that PLGF expression levels were higher in GBC tissues than in normal adjacent tissues and were associated with poor prognosis in GBC patients. Exogenous PLGF enhanced the migration, invasion, and tumorsphere formation of GBC cells. Conversely, knockdown of PLGF decreased the aggressive phenotype of GBC cells. Mechanistically, exogenous PLGF upregulated microRNA-19a (miR-19a) expression through the activation of c-MYC. Moreover, Spearman's correlation analysis showed a positive pairwise correlation among PLGF, c-MYC, and miR-19a expression in GBC tissues. Taken together, these results suggest that PLGF promotes EMT and tumorsphere formation through inducing miR-19a expression by upregulating c-MYC. Thus, PLGF could be a promising molecular therapeutic target for GBC.

Association of TERT-CLPTM1L and 8q24 Common Genetic Variants with Gallbladder Cancer Susceptibility and Prognosis in North Indian Population

Gallbladder carcinoma (GBC) is one of the common malignancy of the biliary tract. Several genome wide and candidate gene studies have reported associations between multiple cancer types and single-nucleotide polymorphisms on 5p15.33 and 8q24.21 loci. However, predisposition potential of these genetic variants has not been assessed in GBC. We performed the present study to assess the potential of five polymorphisms on 5p15.33 and one on 8q24.21 locus in GBC risk and treatment response in patients undergoing chemoradiotherapy. We extracted genomic DNA from peripheral blood and genotyped selected SNPs using TaqMan allelic discrimination assays in 523 GBC cases and 274 controls from the north-Indian population. Statistical tests were performed to assess the association of selected common genetic variants with gallbladder cancer susceptibility and prognosis. Binary logistic regression analysis showed significant association of TERT rs2736100C > A [OR(CI) = 0.690(0.515-0.924), p value = 0.013], CLPTM1L rs401681C > T [OR(CI) = 0.586(0.405-0.847), p value = 0.004], and CASC8 rs6983267G > T [OR(CI) = 1.629(1.215-2.186), p value = 0.001] with GBC risk. Further, using multivariate logistic regression, we observed that haplotype CLPTM1L C_rs401681C_rs31489 TERT T_rs2853676A_rs2736100 MIR4457 G_rs4635969 [OR(CI) = 7.52 (1.79-31.52), p value = 0.0064] is significantly associated with poor treatment response. In survival analysis, Kaplan-Meier survival curves showed significantly poor survival and COX regression suggested significantly higher hazard ratio in TT genotype carriers of CASC8 rs6983267 [OR(CI) = 4.28(1. 07-17.10), p value = 0.040] as compared to major allele and heterozygous (GG+GT) genotypes in metastatic GBC cases. The study revealed that 5p15.33 and 8q24.21 genetic variants significantly influence GBC risk and treatment response in north-Indian population.

Gallbladder cancer epidemiology, pathogenesis and molecular genetics: Recent update

Gallbladder cancer is a malignancy of biliary tract which is infrequent in developed countries but common in some specific geographical regions of developing countries. Late diagnosis and deprived prognosis are major problems for treatment of gallbladder carcinoma. The dramatic associations of this orphan cancer with various genetic and environmental factors are responsible for its poorly defined pathogenesis. An understanding to the relationship between epidemiology, molecular genetics and pathogenesis of gallbladder cancer can add new insights to its undetermined pathophysiology. Present review article provides a recent update regarding epidemiology, pathogenesis, and molecular genetics of gallbladder cancer. We systematically reviewed published literature on gallbladder cancer from online search engine PubMed (http://www.ncbi.nlm.nih.gov/pubmed). Various keywords used for retrieval of articles were Gallbladder, cancer Epidemiology, molecular genetics and bullion operators like AND, OR, NOT. Cross references were manually searched from various online search engines (http://www.ncbi.nlm.nih.gov/pubmed,https://scholar.google.co.in/, http://www.medline.com/home.jsp). Most of the articles published from 1982 to 2015 in peer reviewed journals have been included in this review.