Micro‐RNA29b enhances the sensitivity of glioblastoma multiforme cells to temozolomide by promoting autophagy

• Published in: Anatomical record (Hoboken, N.J. : 2007) Vol. 304; no. 2; pp. 342 - 352
• Main Authors: Xu, Jing‐Xuan, Yang, Yan, Zhang, Xu, Luan, Xin‐Ping
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.02.2021; Wiley Subscription Services, Inc
• Subjects: Animals; Antineoplastic Agents, Alkylating - pharmacology; Antitumor activity; Apoptosis; Apoptosis - drug effects; Apoptosis - genetics; Autophagy; Autophagy - drug effects; Autophagy - genetics; Brain cancer; Brain Neoplasms - genetics; Brain Neoplasms - metabolism; Brain Neoplasms - pathology; Cell Line, Tumor; Cell Proliferation - drug effects; Cell Proliferation - genetics; Cell viability; Cholecystokinin; Flow cytometry; Glioblastoma; Glioblastoma - genetics; Glioblastoma - metabolism; Glioblastoma - pathology; glioblastoma multiforme; Humans; Mice; microRNA29b; MicroRNAs - genetics; MicroRNAs - metabolism; Phagocytosis; Signal Transduction - drug effects; siRNA; Temozolomide; Temozolomide - pharmacology; Western blotting; Xenograft Model Antitumor Assays; Xenografts; temozolomide; glioblastoma multiforme; autophagy; microRNA29b
• ISSN: 1932-8486; 1932-8494
• DOI: 10.1002/ar.24400

To explore whether or not aberrant expression of miR‐29b in glioblastoma multiforme (GBM) cells was associated with temozolomide (TMZ) resistance and to elucidate potential underlying mechanisms. Upregulation of miR‐29 in GBM cells was achieved by transfecting miR‐29b mimics. Changes in cell viability were measured by using CCK‐8 assays. Flow cytometry and TUNEL assays were used to quantify the number of apoptotic cells. The expression levels of apoptosis‐related proteins as well as autophagy‐associated proteins, and the expression levels of both apoptotic and autophagic genes were determined by Western blotting. Autophagy flux was monitored by transfecting mRFP‐GFP‐LC3 adenovirus. We halted autophagy by introducing Atg 5‐specific siRNA or the autophagy inhibitor Bafilomycin A1 (Baf‐A1). We also employed a GBM xenograft mice model to confirm the role of miR‐29b in vivo. miR‐29b overexpression induced inhibition of cell viability, and also induced apoptosis and autophagy in U251 and U87MG cells. Furthermore, upregulation of miR‐29b was able to potentiate the level of antitumor activity of TMZ against tested cells. We also found that autophagy induced by miR‐29b, at least partially, contributed to the increase of TMZ sensitivity in GBM cells. As was evidenced by blockade of autophagy, the application of Atg 5 siRNA or Baf‐A1 was able to significantly reverse these effects. Consistent with observations in vitro, findings of in vivo assessment also confirmed that overexpression of miR‐29b was able to effectively halt tumor growth and enhance the antitumor activity of TMZ. miR‐29b potentiates TMZ sensitivity against GBM cells by inducing autophagy and the combined use of miR‐29 mimic and TMZ might represent a potential therapeutic strategy for GBM patients.