scholarly journals The CAGE–MiR-181b-5p–S1PR1 Axis Regulates Anticancer Drug Resistance and Autophagy in Gastric Cancer Cells

Author(s):  
Minjeong Yeon ◽  
Youngmi Kim ◽  
Deepak Pathak ◽  
Eunju Kwon ◽  
Dong Young Kim ◽  
...  

Cancer-associated gene (CAGE), a cancer/testis antigen, has been known to promote anticancer drug resistance. Since the underlying mechanisms of CAGE-promoted anticancer drug resistance are poorly understood, we established Anticancer drug-resistant gastric cancer cells (AGSR) to better elucidate possible mechanisms. AGSR showed an increased expression level of CAGE and autophagic flux compared with anticancer drug-sensitive parental gastric cancer cells (AGS cells). AGSR cells showed higher invasion potential, growth rate, tumor spheroid formation, and angiogenic potential than AGS cells. CAGE exerted effects on the response to anticancer drugs and autophagic flux. CAGE was shown to bind to Beclin1, a mediator of autophagy. Overexpression of CAGE increased autophagic flux and invasion potential but inhibited the cleavage of PARP in response to anticancer drugs in CAGE CRISPR–Cas9 cell lines. TargetScan analysis was utilized to predict the binding of miR-302b-5p to the promoter sequences of CAGE, and the results show that miR-302b-5p directly regulated CAGE expression as illustrated by luciferase activity. MiR-302b-5p regulated autophagic flux and the response to anticancer drugs. CAGE was shown to bind the promoter sequences of miR-302b-5p. The culture medium of AGSR cells increased CAGE expression and autophagic flux in AGS cells. ImmunoEM showed CAGE was present in the exosomes of AGSR cells; exosomes of AGSR cells and human recombinant CAGE protein increased CAGE expression, autophagic flux, and resistance to anticancer drugs in AGS cells. MicroRNA array revealed miR-181b-5p as a potential negative regulator of CAGE. MiR-181b-5p inhibitor increased the expression of CAGE and autophagic flux in addition to preventing anticancer drugs from cleaving poly(ADP-ribose) polymerase (PARP) in AGS cells. TargetScan analysis predicted sphingosine 1-phosphate receptor 1 (SIPR1) as a potential target for miR-181b-5p. CAGE showed binding to the promoter sequences of S1PR1. The downregulation or inhibition of S1PR1 led to decreased autophagic flux but enhanced the sensitivity to anticancer drugs in AGSR cells. This study presents a novel role of the CAGE–miR-181b-5p–S1PR1 axis in anticancer drug resistance and autophagy.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 60-60
Author(s):  
Osamu Maeda ◽  
Kazuhiro Ishiguro ◽  
Kohei Funasaka ◽  
Ryoji Miyahara ◽  
Yoshiki Hirooka ◽  
...  

60 Background: Resistance to anti-cancer drugs is a critical issue in treatment of cancer. Alteration of gene expression profile accompanied with acquisition of drug-resistance is considered to be related with resistance mechanisms. Methods: 1. Ascitic fluids were collected before the beginning of CapeOX, during the treatment was effective, and after the disease was progressed. They were cultured for ten days and passed to new flasks, and were cultured in additional two weeks to remove normal cells including white blood cells and mesothelial cells. 2. AGS cells were cultured in medium with either fluorouracil or oxaliplatin, and fluorouracil- or oxaliplatin-resistant cells were established. AGS cells were also treated with a demethylating agent decitabine. 3. Expression of 25,147 genes was analyzed with microarray, and was compared among ascitic fluid cells before and after CapeOX, drug-resistant AGS cells, and decitabine-treated AGS cells. Results: Genes with alteration in expression due to CapeOX-resistance were classified into genes commonly changed with fluorouracil-resistant cells, those with oxaliplatin-resistant cells, and others. Among 873 genes with decreased expression after CapeOX, some genes including PCDH20 and DEFB4A have been reported as potential tumor suppressor genes. Expression of PCHD20 in AGS increased after treatment with decitabine. Conclusions: Drug-resistance in gastric cancer may be related with expression of genes including tumor suppressors regulated by epigenetic mechanisms. Repetitive collection of gastric cancer cells in ascitic fluids before and after chemotherapy is useful to understand drug-resistance mechanisms.


2020 ◽  
Vol 20 ◽  
Author(s):  
En Xu ◽  
Hao Zhu ◽  
Feng Wang ◽  
Ji Miao ◽  
Shangce Du ◽  
...  

: Gastric cancer is one of the most common malignancies worldwide and the third leading cause of cancer-related death. In the present study, we investigated the potential activity of OSI-027, a potent and selective mammalian target of rapamycin complex 1/2 (mTOR1/2) dual inhibitor, alone or in combination with oxaliplatin against gastric cancer cells in vitro. Cell counting kit-8 assays and EdU staining were performed to examine the proliferation of cancer cells. Cell cycle and apoptosis were detected by flow cytometry. Western blot was used to detect the elements of the mTOR pathway and Pgp in gastric cancer cell lines. OSI-027 inhibited the proliferation of MKN-45 and AGS cells by arresting the cell cycle in the G0/G1 phase. At the molecular level, OSI-027 simultaneously blocked mTORC1 and mTORC2 activation, and resulted in the downregulation of phosphor-Akt, phpspho-p70S6k, phosphor-4EBP1, cyclin D1, and cyclin-dependent kinase4 (CDK4). Additionally, OSI-027 also downregulated P-gp, which enhanced oxaliplatin-induced apoptosis and suppressed multidrug resistance. Moreover, OSI-027 exhibited synergistic cytotoxic effects with oxaliplatin in vitro, while a P-gp siRNA knockdown significantly inhibited the synergistic effect. In summary, our results suggest that dual mTORC1/mTORC2 inhibitors (e.g., OSI-027) should be further investigated as a potential valuable treatment for gastric cancer.


2017 ◽  
Vol 14 (2) ◽  
pp. 2499-2504 ◽  
Author(s):  
Zhongwei He ◽  
Xiangling Xiao ◽  
Shan Li ◽  
Yang Guo ◽  
Qiuyue Huang ◽  
...  

2005 ◽  
Vol 37 (5) ◽  
pp. 391-398 ◽  
Author(s):  
Pyoung Han Hwang ◽  
Sun Young Kim ◽  
Jung Chang Lee ◽  
Sun Jun Kim ◽  
Ho Keun Yi ◽  
...  

2020 ◽  
Author(s):  
Jinyan Zhao ◽  
Weilan Lan ◽  
Jun Peng ◽  
Bin Guan ◽  
Jie Liu ◽  
...  

Abstract Background: Multidrug resistance (MDR) is a critical reason of cancer chemotherapy failure. Babao dan (BBD) is a classical and famous traditional Chinese patent medicine, which has been reported to has anti-gastric cancer activity. However, the roles and molecular mechanisms of the reversal of MDR of gastric cancer by BBD have not been well described until now. Methods: SGC-7901 and SGC-7901/DDP cells were used in this study, and drug resistance and evaluation of the reversal effect of BBD was determined using MTT assays in SGC7901/DDP cells. Doxorubicin (DOX) and Rhodamin123 (Rho123) staining was performed to assess BBD effects on drug accumulation and efflux of drug-resistant gastric cancer cells. Cell apoptosis was directly assessed using DAPI staining. Apoptotic and dead cells were detected by flow cytometry after staining with Annexin V-FITC and propidium iodide (PI). Cyto-ID assays were performed to examine cellular autophagy. Changes in cell protein expression of ABCB1, ABCC1, ABCG2, Bax, Bcl-2, caspase-3, cleaved-caspase-3, LC3, p62, Beclin1 and the PI3K/AKT/mTOR pathway were detected by Western blot. Inhibition of autophagy with 3-MA, chloroquine (CQ) and PI3K antagonist (LY294002) or agonist (740Y-P) , uncovered a role for the potentially downregulated signaling pathway, PI3K/AKT/mTOR.Results: The SGC7901/DDP cell line exhibited multi-drug resistance to DDP, DOX and 5-fluorouracil (5-FU) and the drug resistant index (RI) of DDP, DOX and 5-FU were 1.86, 1.50 and 47.70, respectively. BBD reversed the MDR of SGC7901/DDP cells by increasingDOX accumulation, reducing Rh123 efflux and down-regulating the expression of ABCB1, ABCC1, ABCG2. Furthermore, BBD induced apoptosis in SGC7901/DDP cells through regulating caspase-3, cleaved-caspase-3, Bax and Bcl-2. Moreover, BBD induced autophagy in DDP-resistant gastric cancer cells via regulating p62, LC3 and Beclin1. Pathway analyses suggested BBD may inhibit PI3K/AKT/mTOR pathway activity and subsequent autophagy induction. Conclusions: BBD may reverse the MDR of gastric cancer cells, and promote autophagic death via inactivation of the PI3K/AKT/mTOR signaling pathway.


2020 ◽  
Vol 11 ◽  
Author(s):  
Yingying Kou ◽  
Bending Tong ◽  
Weiqing Wu ◽  
Xiangqing Liao ◽  
Min Zhao

Gastric cancer is one of the most common malignancies ranks as the second leading cause of cancer-related mortality in the world. Cisplatin (DDP) is commonly used for gastric cancer treatment, whereas recurrence and metastasis are common because of intrinsic and acquired DDP-resistance. The aim of this study is to examine the effects of berberine on the DDP-resistance in gastric cancer and explore the underling mechanisms. In this study, we established the DDP-resistant gastric cancer cells, where the IC50 values of DDP in the BGC-823/DDP and SGC-7901/DDP were significantly higher than that in the corresponding parental cells. Berberine could concentration-dependently inhibited the cell viability of BGC-823 and SGC-7901 cells; while the inhibitory effects of berberine on the cell viability were largely attenuated in the DDP-resistant cells. Berberine pre-treatment significantly sensitized BGC-823/DDP and SGC-7901/DDP cells to DDP. Furthermore, berberine treatment concentration-dependently down-regulated the multidrug resistance-associated protein 1 and multi-drug resistance-1 protein levels in the BGC-823/DDP and SGC7901/DDP cells. Interestingly, the cell apoptosis of BGC-823/DDP and SGC-7901/DDP cells was significantly enhanced by co-treatment with berberine and DDP. The results from animals also showed that berberine treatment sensitized SGC-7901/DDP cells to DDP in vivo. Mechanistically, berberine significantly suppressed the PI3K/AKT/mTOR in the BGC-823/DDP and SGC-7901/DDP cells treated with DDP. In conclusion, we observed that berberine sensitizes gastric cancer cells to DDP. Further mechanistic findings suggested that berberine-mediated DDP-sensitivity may be associated with reduced expression of drug transporters (multi-drug resistance-1 and multidrug resistance-associated protein 1), enhanced apoptosis and repressed PI3K/AKT/mTOR signaling.


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