Open AccessEffect of Glut‐1 and HIF‐1α double knockout by CRISPR/CAS9 on radiosensitivity in laryngeal carcinoma via the PI3K/Akt/mTOR pathway
Author(s) -
Bao YangYang,
Zhong JiangTao,
Shen LiFang,
Dai LiBo,
Zhou ShuiHong,
Fan Jun,
Yao HongTian,
Lu ZhongJie
Publication year - 2022
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/jcmm.17303
Subject(s) - pi3k/akt/mtor pathway , radioresistance , protein kinase b , cancer research , biology , glucose transporter , viability assay , radiosensitivity , apoptosis , chemistry , signal transduction , medicine , microbiology and biotechnology , endocrinology , cell culture , insulin , biochemistry , radiation therapy , genetics
Hypoxic resistance is the main obstacle to radiotherapy for laryngeal carcinoma. Our previous study indicated that hypoxia‐inducible factor 1α (HIF‐1α) and glucose transporter 1 (Glut‐1) double knockout reduced tumour biological behaviour in laryngeal carcinoma cells. However, their radioresistance mechanism remains unclear. In this study, cell viability was determined by CCK8 assay. Glucose uptake capability was evaluated by measurement of 18 F‐fluorodeoxyglucose radioactivity. A tumour xenograft model was established by subcutaneous injection of Tu212 cells. Tumour histopathology was determined by haematoxylin and eosin staining, immunohistochemical staining, and TUNEL assays. Signalling transduction was evaluated by Western blotting. We found that hypoxia induced radioresistance in Tu212 cells accompanied by increased glucose uptake capability and activation of the PI3K/Akt/mTOR pathway. Inhibition of PI3K/Akt/mTOR activity abolished hypoxia‐induced radioresistance and glucose absorption. Mechanistic analysis revealed that hypoxia promoted higher expressions of HIF‐1α and Glut‐1. Moreover, the PI3K/Akt/mTOR pathway was a positive mediator of HIF‐1α and/or Glut‐1 in the presence of irradiation. HIF‐1α and/or Glut‐1 knockout significantly reduced cell viability, glucose uptake and PI3K/Akt/mTOR activity, all of which were induced by hypoxia in the presence of irradiation. In vivo analysis showed that knockout of HIF‐1α and/or Glut‐1 also inhibited tumour growth by promoting cell apoptosis, more robustly compared with the PI3K inhibitor wortmannin, particularly in tumours with knockout of both HIF‐1α and Glut‐1. HIF‐1α and/or Glut‐1 knockout also abrogated PI3K/Akt/mTOR signalling transduction in tumour tissues, in a manner similar to wortmannin. HIF‐1α and/or Glut‐1 knockout facilitated radiosensitivity in laryngeal carcinoma Tu212 cells by regulation of the PI3K/Akt/mTOR pathway.