Involvement of microRNA-141-3p in 5-fluorouracil and oxaliplatin chemo-resistance in esophageal cancer cells via regulation of PTEN
Authors: Yang Wei
Hong-Tao Ren
Ying-Ying Jin
Qing-Juan Chen
Xing Bao
Kun Xu
Hong Bing Ma
Yi-Nan Ma
Journal: Molecular and Cellular Biochemistry (2016)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Cell line; Chemotherapy; Esophageal squamous cell carcinoma; Resistance; Xenograft
Affiliations: Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, No. 157, Xiwulu, Xi'an, 710004, Shaanxi, China., Department of Oncology, Xian Yang Center Hospital, Xian Yang, 610041, Shaanxi, China., Scientific Research Center, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, Shaanxi, China., Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, No. 157, Xiwulu, Xi'an, 710004, Shaanxi, China. .

Abstract:  microRNAs (miRNAs) act as a major regulator of acquired chemo-resistance in various types of cancer therapeutics. This study investigated the contribution of miRNAs in influencing multiple drug resistance in esophageal squamous cell carcinoma (ESCC). The sensitivity of four ESCC cell lines (EC109, EC9706, TE-1 and KYSE-150) to 5-fluorouracil (5-FU) and oxaliplatin (OX) was determined by MTT assay. A 5-FU and OX-resistant subline, EC9706R, was established by continuous exposure to stepwise increasing concentration of 5-FU and OX. Microarray technology was used to compare the differential expression of miRNAs between resistant cells and parental cells. Chemo-sensitivity assay was performed to evaluate drug response in EC9706R cells transfected with miRNA mimic or inhibitor. The direct targets of miRNA were identified by employing pathway analysis and then confirmed with luciferase assay. Sixty ESCC tissue samples and their paired adjacent normal tissues were collected to validate the expression of identified miRNA. Mouse models were further utilized to investigate the function of miRNA on acquired chemo-resistance. MicroRNA panel results indicated that a total of 12 miRNAs were differentially expressed and miR-141-3p was highly over expressed in resistant cells. Inhibition of miR-141-3p reversed acquired chemo-resistance in EC9706R cells by stimulating apoptosis. The expression of miR-141-3p was significantly increased in ESCC tissue samples compared to their matched distant normal tissues. In addition, the elevated miR-141-3p expression was found to be associated with ESCC differentiation status and TNM stage. Moreover, Phosphatase and tensin homolog (PTEN) was identified as direct target of miR-141-3p. Western blot exhibited altered protein levels of PTEN, Akt, and PI3k with miR-141-3p inhibitor. An inverse correlation between PTEN expression and miR-141-3p expression was also observed in tissue samples. EC9706R xenograft mouse model became sensitized to 5-FU and OX treatment following miR-141-3p inhibitor transfection in vivo. Our study demonstrated that miR-141-3p contributed to an acquired chemo-resistance through PTEN modulation both in vitro and in vivo. 

Retracted: No

PubPeer comments:
 Fig 5(c).  c Protein levels of PTEN-regulated genes following miRNA-141-3p inhibitor transfection also subsequently changed. ![file] Coloured rectangles to facilitate comparison with *[left]* Figure 7 from [Yang et al (2019)] .  Isoacteoside inhibited the AKT PI3K mTOR pathway as shown by western blot analysis. *[right]* Figure 6 from [Xu et al (2013)] .  Effect of JB on the PI3K Akt mTOR signal pathway in tumor tissues. Proteins were extracted, then cyclinD1, cyclinE, p-PI3K, p-Akt, PTEN, mTOR and p-eIF4E expressions were determined by western blot analysis. ![file] For further comparison: Figure 9 from [Zhao et al (2016)] .  Effect of amarogentin on the m-TOR, cyclin D1, cyclin E, PI3K Akt pathways in human gastric (SNU16) cancer cells. The expressions of these proteins were evaluated by Western blot analysis . ![file] ,