[Preliminary Investigation of the Molecular Mechanism of Empagliflozin Suppressing Gastric Cancer Through Mammalian Target of Rapamycin]. / æ©æ ¼åˆ—å‡€é€šè¿‡é›·å¸•éœ‰ç´ é¶ç‚¹è›‹ç™½æŠ‘åˆ¶èƒƒç™Œçš„åˆ†å­æœºåˆ¶åˆæŽ¢.

Objective: To predict the intervention targets of empagliflozin (EMPA), a specific inhibitor of sodium-glucose cotransporter 2 (SGLT2), in gastric adenocarcinoma through comprehensive network pharmacology, and to validate the effects and the molecular mechanisms of EMPA through cellular and molecular biology experiments. Methods: Bioinformatics analysis of gastric adenocarcinoma was conducted to assess the correlation between gastric adenocarcinoma prognosis and SGLT2 expression. Network pharmacology was utilized to identify shared targets of EMPA and gastric adenocarcinoma. AGS cells, a human gastric adenocarcinoma cells line, were incubated with EMPA at different concentrations for 24 h and, then, cell proliferation was assessed using the CCK8 assay. After AGS cells were incubated with EMPA at the doses of 0, 3, and 6 mmol/L, real-time cell analysis (RTCA) and 5-ethynyl-2-deoxyuridine (EdU) incorporation were used to evaluate EMPA's inhibitory effects on the proliferation of the AGS cells. In addition, wound healing and Transwell assays were performed to assess the inhibitory effect of EMPA on the migration and invasion of the APC cells and Western blot analysis was conducted to examine the expression of mammalian target of rapamycin (mTOR) and phosphorylated mTOR (p-mTOR). BALB/c (nu/nu) nude mice were implanted with 5×106 AGS cells in the axilla. The mice were divided into three groups, a control group, a low-dose group, and a high-dose group, each consisting of 7 mice. After one week, the control group received daily intraperitoneal injections of normal saline, while the low-dose group and high-dose group received daily intraperitoneal injections of EMPA at the doses of 3 mg/kg and 5 mg/kg, respectively. The tumor volume was measured one week after the drug intervention started. Results: Gastric adenocarcinoma patients with low expression of SGLT2 exhibited longer survival time and higher survival rate than those with high expression of SGLT2 did. A total of 104 EMPA-related potential targets and 2028 targets associated with gastric adenocarcinoma were identified. Among these, 45 targets associated with gastric adenocarcinoma overlapped with potential targets of EMPA. Further analysis revealed 10 relevant pathways and 4 core genes. The core genes were cyclin-dependent kinase 4 (CDK4), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), mTOR, and cyclin E1 (CCNE1). CCK-8 assay revealed that EMPA at concentrations ranging from 0.39 to 50 mmol/L effectively inhibited the proliferation of AGS cells. RTCA results indicated a downward shift in the cell growth curve. In comparison to the findings for the control group, EdU assay demonstrated that EMPA at the concentrations of 3 mmol/L and 6 mmol/L significantly inhibited AGS cell proliferation (P<0.05). Results from wound healing and Transwell assays indicated a decrease in the levels of cell migration and invasion (P<0.05) and, notably, there was a significant difference between the high and low-dose EMPA groups (P<0.05). Western blot showed no statistically significant difference in the expression of total mTOR protein between the groups. However, the expression of p-mTOR in the 3 mmol/L and 6 mmol/L EMPA groups decreased compared to that of the control group (P<0.05), with the 6 mmol/L EMPA group exhibiting a more pronounced reduction (P<0.05). Nude mice xenograft tumor experiment demonstrated that, compared to that of the control group, the tumor volumes in the EMPA-treatment groups were significantly reduced (P<0.05), with the high-dose group showing a more pronounced reduction (P<0.05). Conclusion: EMPA inhibits the abnormal proliferation and migration of gastric adenocarcinoma cells, potentially through the modulation of mTOR protein activation. This study provides new potential medication and intervention targets for gastric adenocarcinoma treatment.

The interaction between PDCD4 and YB1 is critical for cervical cancer stemness and cisplatin resistance.

Cancer multidrug resistance (MDR) is existence in stem cell-like cancer cells characterized by stemness including high-proliferation and self-renewal. Programmed cell death 4 (PDCD4), as a proapoptotic gene, whether it engaged in cancer stemness and cisplatin resistance is still unknown. Here we showed that PDCD4 expressions in Hela/DDP (cisplatin resistance) cells were lower than in parental Hela cells. Moreover, the levels of drug resistance genes and typical stemness markers were markedly elevated in Hela/DDP cells. In vivo, xenograft tumor assay confirmed that knockdown of PDCD4 accelerated the grafted tumor growth. In vitro, colony formation and MTT assay demonstrated that PDCD4 overexpression inhibited cells proliferation in conditions with or without cisplatin. By contrast, PDCD4 deficiency provoked cell proliferation and cisplatin resistance. On mechanism, PDCD4 decreased the protein levels of pAKT and pYB1, accompanied by reduced MDR1 expression. Correspondingly, luciferase reporter assay showed PDCD4 regulated MDR1 promoter activity entirely relied on YB1. Furthermore, Ch-IP, GST-pulldown, and Co-IP assays provided novel evidence that PDCD4 could directly bind with YB1 by the nucleolar localization signal (NOLS) segment, causing the reduced YB1 binding into the MDR1 promoter region through blocking YB1 nucleus translocation, triggering the decreased MDR1 transcription. Taken together, PDCD4-pAKT-pYB1 forms the integrated molecular network to regulate MDR1 transcription during the process of stemness-associated cisplatin resistance.

Nucleolin Promotes Cisplatin Resistance in Cervical Cancer by the YB1-MDR1 Pathway.

PURPOSE: Cervical cancer is the fourth most common cancer in women worldwide and is the main cause of cancer-related deaths in women. Cisplatin (DDP) is one of the major chemotherapeutic drugs for cervical cancer patients. But, drug resistance limits the effectiveness of cancer therapy. Nucleolin (NCL) is a nucleocytoplasmic multifunctional protein involved in the development of cancer. It has been reported that NCL may be a potential target for modulation of drug resistance. However, the precise molecular mechanisms are poorly understood. MATERIALS AND METHODS: Human cervical cancer Hela cells and their cisplatin-resistant cell line Hela/DDP were used in this study. The protein level of NCL in cervical cancer cells was measured by western blot analysis. Hela cells and Hela/DDP cells were transfected with NCL overexpression plasmid or NCL siRNA separately. MTT and EdU assay were performed to evaluate the cell viability and sensitivity to cisplatin. The drug efflux function of MDR1 protein was assessed by intracellular rhodamine-123 accumulation assay.The promoter activity of MDR1 was assessed by using a dual-luciferase reporter assay. RESULTS: We found that the protein level of NCL was elevated in Hela/DDP cells. Overexpression of NCL increased cervical cancer cell proliferation and attenuated the sensitivity to cisplatin. Overexpression of NCL increased Multidrug resistance (MDR1) gene expression and drug efflux. Our results demonstrated that NCL was highly related with cisplatin resistance in cervical cancer. NCL played an important role in MDR1 gene transcription through regulation of the transcription factor YB1. CONCLUSION: Our findings revealed the novel role of NCL in cisplatin-resistant cervical cancer and NCL may be a potential therapeutic target for chemoresistance.