Genomic and epigenomic heterogeneity in molecularsubtypes of gastric cancer

Gastric cancer is a complex disease that is affected by multiple genetic and environmental factors. For the precise diagnosis and effective treatment of gastric cancer, the heterogeneity of the disease must be simplified; one way to achieve this is by dividing the disease into subgroups. Toward this effort, recent advances in high-throughput sequencing technology have revealed four molecular subtypes of gastric cancer, which are classified as Epstein-Barr viruspositive, microsatellite instability, genomically stable, and chromosomal instability subtypes. We anticipate that this molecular subtyping will help to extend our knowledge for basic research purposes and will be valuable for clinical use. Here, we review the genomic and epigenomic heterogeneity of the four molecular subtypes of gastric cancer. We also describe a mutational meta-analysis and a reanalysis of DNA methylation that were performed using previously reported gastric cancer datasets.

Mutation analysis of 13 driver genes of colorectalcancer-related pathways in Taiwan Residents patients

AIM To investigate the driver gene mutations associatedwith colorectal cancer （CRC） in the Taiwan Residentspopulation.METHODS： In this study, 103 patients with CRCwere evaluated. The samples consisted of 66 menand 37 women with a median age of 59 years and anage range of 26-86 years. We used high-resolutionmelting analysis （HRM） and direct DNA sequencing tocharacterize the mutations in 13 driver genes of CRCrelatedpathways. The HRM assays were conductedusing the LightCycler？ 480 Instrument provided with the software LightCycler 480 Gene Scanning SoftwareVersion 1.5. We also compared the clinicopathologicaldata of CRC patients with the driver gene mutationstatus.RESULTS： Of the 103 patients evaluated, 73.79%had mutations in one of the 13 driver genes. Wediscovered 18 novel mutations in APC , MLH1 , MSH2 ,PMS2 , SMAD4 and TP53 that have not been previouslyreported. Additionally, we found 16 de novo mutationsin APC , BMPR1A , MLH1 , MSH2 , MSH6 , MUTYH andPMS2 in cancerous tissues previously reported in thedbSNP database; however, these mutations couldnot be detected in peripheral blood cells. The APCmutation correlates with lymph node metastasis（34.69% vs 12.96%, P = 0.009） and cancer stage（34.78% vs 14.04%, P = 0.013）. No association wasobserved between other driver gene mutations andclinicopathological features. Furthermore, having twoor more driver gene mutations correlates with thedegree of lymph node metastasis （42.86% vs 24.07%,P = 0.043）.CONCLUSION： Our findings confirm the importanceof 13 CRC-related pathway driver genes in the developmentof CRC in Taiwan Residents patients.

Huangqi Decoction,a compound Chinese herbal medicine,inhibits the proliferation and activation of hepatic stellate cells by regulating the long noncoding RNA-C18orf26-1/microRNA-663a/transforming growth factor-βaxis

Objective Huangqi Decoction(HQD),a classical traditional Chinese medicine formula,has been used as a valid treatment for alleviating liver fibrosis;however,the underlying molecular mechanism is still unknown.Although our previous studies showed that microRNA-663a(miR-663a)suppresses the proliferation and activation of hepatic stellate cells(HSCs)and the transforming growth factor-β/small mothers against decapentaplegic(TGF-β/Smad)pathway,whether long noncoding RNAs(lncRNAs)are involved in HSC activation via the miR-663a/TGF-β/Smad signaling pathway has not yet reported.The present study aimed to investigate the roles of lncRNA lnc-C18orf26-1 in the activation of HSCs and the mechanism by which HQD inhibits hepatic fibrosis.Methods The expression levels of lnc-C18orf26-1,miR-663a and related genes were measured by quantitative reverse transcription-polymerase chain reaction.HSCs were transfected with the miR-663a mimic or inhibitor and lnc-C18orf26-1 small interfering RNAs.The water-soluble tetrazolium salt-1 assay was used to assess the proliferation rate of HSCs.Changes in lncRNA expression were evaluated in miR-663a-overexpressing HSCs by using microarray to identify miR-663a-regulated lncRNAs.RNA hybrid was used to predict the potential miR-663a binding sites on lncRNAs.Luciferase reporter assays further confirmed the interaction between miR-663a and the lncRNA.The expression levels of collagen α-2(I)chain(COL1A2),α-smooth muscle actin(α-SMA)and TGF-β/Smad signaling pathway-related proteins were determined using Western blotting.Results Lnc-C18orf26-1 was upregulated in TGF-β1-activated HSCs and competitively bound to miR-663a.Knockdown of lnc-C18orf26-1 inhibited HSC proliferation and activation,downregulated TGF-β1-stimulatedα-SMA and COL1A2 expression,and inhibited the TGF-β1/Smad signaling pathway.HQD suppressed the proliferation and activation of HSCs.HQD increased miR-663a expression and decreased lnc-C18orf26-1 expression in HSCs.Further studies showed that HQD inhibited the expression of COL1A2,α-SMA,TGF-β1,TGF-βtype I receptor(TGF-βRI)and phosphorylated Smad2(p-Smad2)in HSCs,and these effects were reversed by miR-663a inhibitor treatment.Conclusion Our study identified lnc-C18orf26-1 and miR-663a as promising therapeutic targets for hepatic fibrosis.HQD inhibits HSC proliferation and activation at least partially by regulating the lnc-C18orf26-1/miR-663a/TGF-β1/TGF-βRI/p-Smad2 axis.