Blocking lncRNA-SNHG16 sensitizes gastric cancer cells to 5-Fu through targeting the miR-506-3p-PTBP1-mediated glucose metabolism

Abstract

Background Gastric cancer (GC) is a commonly occurring human malignancy. The 5-fluorouracil (5-Fu) is a first-line anti-gastric cancer agent. However, a large number of GC patients developed 5-Fu resistance. Currently, the roles and molecular mechanisms of the lncRNA-SNHG16-modulated 5-Fu resistance in gastric cancer remain elusive. Methods Expressions of lncRNA, miRNA, and mRNA were detected by qRT-PCR and Western blot. RNA-RNA interaction was examined by RNA pull-down and luciferase assay. Cell viability and apoptosis rate under 5-Fu treatments were determined by MTT assay and Annexin V assay. The glycolysis rate of GC cells was evaluated by glucose uptake and ECAR. Results Here, we report that SNHG16 as well as PTBP1, which is an RNA-binding protein, are positively associated with 5-Fu resistance to gastric cancer. SNHG16 and PTBP1 were significantly upregulated in gastric tumors and cell lines. Silencing SNHG16 or PTBP1 effectively sensitized GC cells to 5-Fu. Furthermore, glucose metabolism was remarkedly elevated in 5-Fu-resistant GC cells. Under low glucose supply, 5-Fu-resistant cells displayed higher vulnerability than parental GC cells. Bioinformatic analysis and luciferase assay demonstrated that SNHG16 downregulated miR-506-3p by sponging it to form a ceRNA network. We identified PTBP1 as a direct target of miR-506-3p in GC cells. RNA-seq results unveiled that PTBP1 positively regulated expressions of multiple glycolysis enzymes, including GLUT1, HK2, and LDHA. Bioinformatic analysis illustrated the 3′UTRs of glycolysis enzymes contained multiple PTBP1 binding sites, which were further verified by RNA pull-down and RNA immunoprecipitation assays. Consequently, we demonstrated that PTBP1 upregulated the mRNAs of glycolysis enzymes via promoting their mRNA stabilities. Finally, in vivo xenograft experiments validated that blocking the SNHG16-mediated miR-506-3p-PTBP1 axis effectively limited 5-Fu-resistant GC cell originated-xenograft tumor growth under 5-Fu treatments. Conclusions Our study demonstrates molecular mechanisms of the SNHG16-mediated 5-Fu resistance of GC cells through modulating the miR-506-3p-PTBP1-glucose metabolism axis, presenting a promising approach for anti-chemoresistance therapy.

Mechanism of lncRNA SNHG16 on kidney clear cell carcinoma cells by targeting miR-506-3p/ETS1/RAS/ERK molecular axis

“…Elevated SNHG1 was observed after transfection with abnormally expressed SNHG1, as well as increased ETS-1 and Ras/ERK signaling pathway and decreased miR-506-3p in KIRC cells, and silencing SNHG1 achieved opposite results, suggesting that the molecular pathway above was also involved in the process of SNHG1 affecting the biological behavior of KIRC cells. In previous studies, although the regulation of miR-506-3p/ETS1/RAS/ERK activity in tumor cells such as gastric and esophageal carcinomas has been shown [ [33] , [34] , [35] ], their role in KIRC remains to be verified. More experiments are still needed to confirm the pathway of action of SNHG1 in relation to miR-506-3p/ETS1/RAS/ERK.…”

New insights into the interaction between m6A modification and lncRNA in cancer drug resistance

“…This leads to the synthesis of pyruvate, alanine, and lactate 96,97 . The expression of lncRNA SNHG16 has been found to be positively correlated with glucose metabolism and resistance 5‐Fu treatment in gastric cancer 98 . Mechanistically, SNHG16 is able to downregulate several glycolysis enzymes, including GLUT1, HK2, and LDHA, through the miR‐506‐3p/PTBP1 axis.…”

Functional role of lncRNAs in gastrointestinal malignancies: the peculiar case of small nucleolar RNA host gene family

“…This lncRNA also sponges miR‐26a‐5p and promotes 5‐FU chemoresistance in CRC [142]. Other examples of drug resistance mediated by SNHGs include SNHG8 which alters the expression of Caspase‐3 and PARP to promote chemo‐resistance in pancreatic adenocarcinoma [143]; SNHG15 that interacts with AIF and increases resistance to 5‐FU in CRC [144]; and SNHG16 that contributes to 5‐FU resistance by targeting miR‐506‐3p in GC [145] and miR‐93 in HCC [146].…”