Resistance to 5‐fluorouracil (5‐FU) is still a primary setback to the success of colorectal cancer (CRC) chemotherapy. Transmembrane protein 97 (TMEM97) functions as an oncogene in CRC. However, the role and mechanism of TMEM97 in regulating 5‐FU resistance in CRC cells remains unclear. TMEM97 expression in CRC samples was analyzed by GEPIA and human protein atlas (HPA) databases. TMEM97, E‐cadherin, Vimentin, N‐cadherin, P‐glycoprotein (P‐gp), multidrug resistance‐associated protein 1 (MRP1)/ABCC1, ABCC2, and the changes of protein kinase B/mammalian target of rapamycin (mTOR) pathway were explored by western blot analysis. IC50 value for 5‐FU and cell viability was examined by MTT assay. Apoptosis was evaluated by flow cytometry. TMEM97 was highly expressed in colon adenocarcinoma (COAD) and rectum adenocarcinoma (READ) based on GEPIA and HPA databases. TMEM97 knockdown attenuated 5‐FU resistance in HCT116/R and SW480/R cells, as evidenced by the reduced IC50 value for 5‐FU and the increased apoptosis. TMEM97 knockdown suppressed epithelial‐mesenchymal transition (EMT), expression of ATP‐binding cassette (ABC) transporters, and the Akt/mTOR pathway. Mechanistically, activation of Akt/mTOR pathway abolished the inhibitory effects of TMEM97 knockdown on 5‐FU resistance, EMT, and ABC transporter expression. In conclusion, TMEM97 knockdown inhibited 5‐FU resistance in CRC by regulating EMT and ABC transporter expression via inactivating the Akt/mTOR pathway.

中文翻译：

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TMEM97 敲低通过调节上皮间质转化和 ABC 转运蛋白表达（通过灭活 5 氟尿嘧啶耐药结直肠癌细胞中的 Akt/mTOR 通路）抑制 5 氟尿嘧啶耐药

对 5-氟尿嘧啶 (5-FU) 的耐药性仍然是结直肠癌 (CRC) 化疗成功的主要障碍。跨膜蛋白 97 (TMEM97) 在 CRC 中充当癌基因。然而，TMEM97 在调节 CRC 细胞 5-FU 耐药性中的作用和机制仍不清楚。通过 GEPIA 和人类蛋白质图谱 (HPA) 数据库分析 CRC 样本中的 TMEM97 表达。TMEM97、E-钙粘蛋白、波形蛋白、N-钙粘蛋白、P-糖蛋白（P-gp）、多药耐药相关蛋白1（MRP1）/ABCC1、ABCC2以及蛋白激酶B/哺乳动物雷帕霉素靶蛋白（mTOR）的变化通过蛋白质印迹分析探索途径。通过 MTT 测定检测 5-FU 的 IC50 值和细胞活力。通过流式细胞术评估细胞凋亡。根据 GEPIA 和 HPA 数据库，TMEM97 在结肠腺癌 (COAD) 和直肠腺癌 (READ) 中高表达。TMEM97 敲低减弱了 HCT116/R 和 SW480/R 细胞中的 5-FU 耐药性，5-FU 的 IC50 值降低和细胞凋亡增加证明了这一点。TMEM97 敲低可抑制上皮间质转化 (EMT)、ATP 结合盒 (ABC) 转运蛋白的表达以及 Akt/mTOR 通路。从机制上讲，Akt/mTOR 通路的激活消除了 TMEM97 敲低对 5-FU 耐药性、EMT 和 ABC 转运蛋白表达的抑制作用。总之，TMEM97 敲除通过失活 Akt/mTOR 通路来调节 EMT 和 ABC 转运蛋白表达，从而抑制 CRC 中的 5-FU 耐药性。