Regulation of microtubule-associated protein tau (MAPT) by miR-34c-5p determines the chemosensitivity of gastric cancer to paclitaxel

• Published in: Cancer chemotherapy and pharmacology Vol. 71; no. 5; pp. 1159 - 1171
• Main Authors: Wu, Hao, Huang, Min, Lu, Mingjie, Zhu, Wei, Shu, Yongqian, Cao, Peng, Liu, Ping
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.05.2013; Springer; Springer Nature B.V
• Subjects: Adenosine Triphosphate - metabolism; Adult; Aged; Aged, 80 and over; Antineoplastic agents; Antineoplastic Agents, Phytogenic - pharmacology; Binding Sites; Biological and medical sciences; Blotting, Western; Cancer Research; Cell Line, Tumor; CpG Islands; DNA Methylation; Down-Regulation; Drug Resistance, Neoplasm; Female; Gastroenterology. Liver. Pancreas. Abdomen; Gene Expression Regulation, Neoplastic; General aspects; Humans; Luciferases - metabolism; Male; Medical sciences; Medicine; Medicine & Public Health; MicroRNAs - genetics; MicroRNAs - metabolism; Middle Aged; Oncology; Original Article; Paclitaxel - pharmacology; Pharmacology. Drug treatments; Pharmacology/Toxicology; Polymerase Chain Reaction - methods; Reverse Transcriptase Polymerase Chain Reaction; Stomach Neoplasms - drug therapy; Stomach Neoplasms - pathology; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; tau Proteins - genetics; tau Proteins - metabolism; Tumors; MAPT; Drug resistant; Methylation; miR-34c-5p; Gastric cancer; Paclitaxel; Antineoplastic agent; Treatment resistance; RNA interference; Micro RNA; Malignant tumor; Chromosome B5; Stomach cancer; Gene silencing; Tau protein; Taxane derivatives; Chemosensitivity; Digestive diseases; Mechanism of action; Antimitotic; Cancer; Gastric disease
• ISSN: 0344-5704; 1432-0843
• DOI: 10.1007/s00280-013-2108-y

Background Human miR-34c has been reported to be associated with various human malignancies; however, it remains unknown whether miR-34c is involved in chemoresistance in gastric cancer. The aim of this study was to investigate the role of miR-34c in gastric cancer. Materials and methods The adenosine triphosphate-based tumor chemosensitivity assay was used to measure drug sensitivity in gastric cancer samples. The expression levels of miRNA were determined by reverse transcriptase polymerase chain reaction (PCR) and those of protein were by Western blot analysis. Luciferase activity assay was used to verify the target genes of miRNAs. MTT assay was used to test the drug-resistant phenotype changes in cancer cells via overregulation of miRNAs. The methylation status of neighboring CpG islands of miR-34c-5p was analyzed by Bisulfite Sequencing PCR and methylation-specific PCR. Results Quantitative real-time polymerase chain reaction demonstrated that expression of miR-34c-5p was downregulated in paclitaxel-resistant gastric cancer samples ( p  < 0.01). Cells derived from gastric cancer tissues with low miR-34c-5p expression and high microtubule-associated protein tau (MAPT) protein expression tended to have increased chemoresistance to paclitaxel in vitro. Luciferase activity assay confirmed that the 3′-UTR of MAPT mRNA contains a functional miR-34c-5p binding site. Overexpression of miR-34c-5p significantly downregulated MAPT protein expression and increased the chemosensitivity of paclitaxel-resistant gastric cancer cells. Further investigation demonstrated that differential methylation of CpG islands neighboring the miR-34c promoter regulated the expression of miR-34c-5p in gastric cancer cell lines. Conclusions DNA methylation, dysregulation of miR-34c-5p, and MAPT expression are critical factors in the chemoresistance of gastric cancer to paclitaxel.