Differential association of RANTES-403 and IL-1B-1464 polymorphisms on histological subtypes in male Korean patients with gastric cancer

MicroRNA-137 chemosensitizes colon cancer cells to the chemotherapeutic drug oxaliplatin (OXA) by targeting YBX1

The mechanisms underlying oxaliplatin (OXA) resistance in colon cancer cells are not fully understood. MicroRNAs (miRNAs) play important roles in tumorigenesis and drug resistance. However, the relationship between miRNA and OXA resistance in colon cancer cells has not been previously explored. In this study, we utilized microRNA microarray analysis and real-time PCR to verify that miR-93, miR-191, miR-137, miR-181 and miR-491-3p were significantly down-regulated and that miR-96, miR-21, miR-22, miR-15b and miR-92 were up-regulated in both HCT-15/OXA and SW480/OXA cell lines. Blocking miR-137 caused a significant inhibition of OXA-induced cytotoxicity, therefore, miR-137 was chosen for further research. An in vitro cell viability assay showed that knockdown of miR-137 in HCT-15 and SW480 cells caused a marked inhibition of OXA-induced cytotoxicity. Moreover, we found that miR-137 was involved in repression of YBX1 expression through targeting its 3'-untranslated region. Furthermore, down-regulation of miR-137 conferred OXA resistance in parental cells, while over-expression of miR-137 sensitized resistant cells to OXA, which was partly rescued by YBX1 siRNA. The results of this study may aid the development of therapeutic strategies to overcome colon cancer cell resistance to OXA.

Complement receptor 1 genetic variants contribute to the susceptibility to gastric cancer in chinese population

As the receptor for C3b/C4b, type 1 complement receptor (CR1/CD35) plays an important role in the regulation of complement activity and is further involved in carcinogenesis. This study aimed to elucidate the association of CR1 genetic variants with the susceptibility to gastric cancer in Chinese population. Based on the NCBI database, totally 13 tag single nucleotide polymorphisms (SNPs) were selected by Haploview program and genotyped using iPlex Gold Genotyping Assay and Sequenom MassArray among 500 gastric cancer cases and 500 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression to evaluate the association of each SNP with gastric cancer. Of all selected Tag SNPs , CR1 rs9429942 T > C was found to confer to the risk of developing gastric cancer. Compared with the carriers with rs9429942 TT genotype, those with CT genotype had 88% decreased risk of developing gastric cancer with OR (95%CI) of 0.12 (0.03-0.50). Generalized multifactor dimensionality reduction (GMDR) analysis revealed a significant three-way interaction among rs75422544 C > A, rs10494885 C > T and rs7525160 G > C in the development of gastric cancer with a maximum testing balance accuracy of 56.07% and a cross-validation consistency of 7/10 (P = 0.011). In conclusion, our findings demonstrated the genetic role of CR1 gene in the development of gastric cancer in Chinese population.

Ethnic differences in gastric cancer genetic susceptibility: Allele flips of interleukin gene

Polymorphisms in promoter regions of inflammatory cytokines have been widely studied, and potentially functional polymorphisms have been discovered. Conflicting results from meta-analyses of interleukin (IL)-1B and IL-10 polymorphisms show differences in gastric cancer susceptibilities between Caucasian and Asian populations. In particular, we note the suggestion of an allele flip in IL-1B and IL-10 gene polymorphisms. In Asian populations, the IL-1B-1464G/-511C/-31T haplotype indicates risk for gastric cancer, while the opposite haplotype, IL-1B-1464C/-511T/-31C is the risk-related allele in Caucasians. Furthermore, while IL-10-1082G/-819C/-592C is associated with gastric cancer in Asians, IL-10-1082A/-819T/-592T is linked to gastric cancer risk in Caucasians. These seemingly contradictory results may be attributed to distinct carcinogenic mechanisms underlying the different gastric cancer subtypes. The allele flip observed in IL-10 and gastric cancer appears to reflect allelic heterogeneity, similar to that observed in IL-1B. In this review, we focus on the allele flip phenomenon observed between different ethnic groups in an effort to resolve certain controversial results from recent studies on interleukin polymorphism. In addition, we re-emphasize the importance of stratifying gastric cancer subtypes based on anatomical site and Lauren classification to prevent false associations arising through dilution of true ones.