The long coding RNA GSTM3TV2 acts an oncogene to promote chemoresistance in pancreatic cancer / 中华外科杂志

Objectives@#To examine the expression of the long coding RNA GSTM3TV2 in pancreatic cancer tissues and to examine its role and mechanism in chemoresistance of pancreatic cancer cells.@*Methods@#The expression of lncRNA GSTM3TV2 in 15 pancreatic cancer specimens and corresponding adjacent to cancer tissue samples diagnosed by Department of Pathology, Peking Union Medical College Hospital was detected by real-time PCR.And the expressions of GSTM3TV2 in pancreatic cancer cell AsPC-1, BxPC-3, MIAPaCa-2, PanC-1, SU86.86, T3M4, and chemoresistant cells AsPC-1/GR and MIAPaCa-2/GR, and human pancreatic nestin-expressing cells hTERT-HPNE were detected. Pancreatic cancer cell lines were transfected with GSTM3TV2-pcDNA3.1(+)in order to get cells with GSTM3TV2 overexpression.GSTM3TV2-siRNA was transfected into pancreatic cancer cells to knock down GSTM3TV2. The cell chemoresistance was measured by CCK-8 and flow cytometry assay when incubated with nab-paclitaxel. At the same time, subcutaneous xenograft tumor models were established in nude mice to observe the effect of GSTM3TV2 on chemoresistance of tumor growth in nude mice.Western blot assay was also performed to detect the molecular mechanism of chemoresistance of GSTM3TV2.@*Results@#Comparing toadjacent tissues(0.084±0.019), GSTM3TV2 expression was significantly upregulated in the pancreatic cancer tissues(0.493±0.084) (t=5.146, P<0.05). GSTM3TV2 expression were higher in the chemotherapy resistance pancreatic cancer cells AsPC-1/GR(210.799±19.788) and MIAPaCa-2/GR(122.408±23.419) than that in the AsPC-1(3.793±0.615) and the MIAPaCa-2(5.179±1.095)(t=21.800,P<0.05;t=-18.490,P<0.05). The results of in vivo experiments showed that the volume of subcutaneously transplanted tumors in the overexpressing GSTM3TV2 group ((1 059.609±102.498)mm3) was significantly larger than that in the control group((566.414±81.087) mm3) by treated with nab-paclitaxel(t=4.230,P<0.05).Meanwhile, GSTM3TV2 could promote the expression of Cyclin D1, CDK6, Cyclin E1, Vimentin, N-cadherin, ZEB1, Snail and Slug; but decrease cleaved caspase-3, cleaved PARP in pancreatic cancer cells.@*Conclusions@#The expression level of GSTM3TV2 in pancreatic canceris higher than that in paired adjacent tissues. GSTM3TV2 may act as an oncogene to promote chemoresistance in pancreatic cancer through regulation of cell proliferation, apoptosis, and epithelial-mesenchymal transition.

High prevalence of the GSTM3*A/B polymorphism in sub-Sarahan African populations

A 3-bp insertion/deletion polymorphism in intron 6 of GSTM3 (rs1799735, GSTM3*A/*B) affects the activity of the phase 2 xenobiotic metabolizing enzyme GSTM3 and has been associated with increased cancer risk. The GSTM3*B allele is rare or absent in Southeast Asians, occurs in 5-20 percent of Europeans but was detected in 80 percent of Bantu from South Africa. The wide genetic diversity among Africans led us to investigate whether the high frequency of GSTM3*B prevailed in other sub-Saharan African populations. In 168 healthy individuals from Angola, Mozambique and the São Tomé e Príncipe islands, the GSTM3*B allele was three times more frequent (0.74-0.78) than the GSTM3*A allele (0.22-0.26), with no significant differences in allele frequency across the three groups. We combined these data with previously published results to carry out a multidimensional scaling analysis, which provided a visualization of the worldwide population affinities based on the GSTM3 *A/*B polymorphism.

Pharmacogenetic polymorphisms in Brazilian-born, first-generation Japanese descendants

Brazil hosts the largest Japanese community outside Japan, estimated at 1.5 million individuals, one third of whom are first-generation, Brazilian-born with native Japanese parents. This large community provides a unique opportunity for comparative studies of the distribution of pharmacogenetic polymorphisms in native Japanese versus their Brazilian-born descendants. Functional polymorphisms in genes that modulate drug disposition (CYP2C9, CYP2C19 and GSTM3) or response (VKORC1) and that differ significantly in frequency in native Japanese versus Brazilians with no Japanese ancestry were selected for the present study. Healthy subjects (200 native Japanese and 126 first-generation Japanese descendants) living in agricultural colonies were enrolled. Individual DNA was genotyped using RFLP (GSTM3*A/B) or TaqMan Detection System assays (CYP2C9*2 and *3; CYP2C19*2 and *3; VKORC1 3673G>A, 5808T>G, 6853G>C, and 9041G>A). No difference was detected in the frequency of these pharmacogenetic polymorphisms between native Japanese and first-generation Japanese descendants. In contrast, significant differences in the frequency of each polymorphism were observed between native or first-generation Japanese and Brazilians with no Japanese ancestry. The VKORC1 3673G>A, 6853G>C and 9041G>A single nucleotide polymorphisms were in linkage disequilibrium in both native and first-generation Japanese living in Brazil. The striking similarity in the frequency of clinically relevant pharmacogenetic polymorphisms between Brazilian-born Japanese descendants and native Japanese suggests that the former may be recruited for clinical trials designed to generate bridging data for the Japanese population in the context of the International Conference on Harmonization.