title: AZD2014 Radiosensitizes Oral Squamous Cell Carcinoma by Inhibiting AKT/mTOR Axis and Inducing G1/G2/M Cell Cycle Arrest.
abstract: BACKGROUND
  Oral squamous cell carcinoma (OSCC) is one of the most common malignant neoplasms in Taiwan. Activation of the mTOR signaling pathway has been linked to decreased radiation responsiveness in human oral cancer, thus it limits efficacy of radiotherapy. To address this question, we investigated the effect of AZD2014, a novel small molecular ATP-competitive inhibitor of mTORC1 and mTORC2 kinase, as a radiosensitizer in primary OSCC and OSCC-derived cell line models.
  
  
  METHODS
  We isolated primary tumor cells from OSCC tissues and cell lines. AZD2014 was administered with and without ionizing radiation. The radiosensitizing effect of AZD2014 were then assessed using cell viability assays, clonogenic survival assays, and cell cycle analyses. Western blotting was used to detect protein expression.
  
  
  RESULTS
  Combination treatment with AZD2014 and irradiation resulted in significant reduction in OSCC cell line and primary OSCC cell colony formation due to the enhanced inhibition of AKT and both mTORC1 and mTORC2 activity. Pre-treatment with AZD2014 in irradiated oral cancer cells induced tumor cell cycle arrest at the G1 and G2/M phases, which led to disruption of cyclin D1-CDK4 and cyclin B1-CDC2 complexes. Moreover, AZD2014 synergized with radiation to promote both apoptosis and autophagy by increasing caspase-3 and LC3 in primary OSCC cells.
  
  
  CONCLUSIONS
  These findings suggest that in irradiated OSCC cells, co-treatment with AZD2014, which targets mTORC1 and mTORC2 blockade, is an effective radiosensitizing strategy for oral squamous cell carcinoma.
authors.affiliation: Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi, Taiwan, R.O.C.|Division of Hematology-Oncology, Department of Internal Medicine, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.
authors.forename: Chih-Chia
authors.initials: CC
authors.lastname: Yu
authors.affiliation: Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi, Taiwan, R.O.C.
authors.forename: Hsien-bin
authors.initials: HB
authors.lastname: Huang
authors.affiliation: School of Medicine, Tzu Chi University, Hualian, Taiwan, R.O.C.|Department of Radiation Oncology, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.
authors.forename: Shih-Kai
authors.initials: SK
authors.lastname: Hung
authors.affiliation: Department of Biochemical Science and Technology, National Chiayi University, Chia-Yi, Taiwan, R.O.C.
authors.forename: Hui-Fen
authors.initials: HF
authors.lastname: Liao
authors.affiliation: School of Medicine, Tzu Chi University, Hualian, Taiwan, R.O.C.|Department of Otolaryngology, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.
authors.forename: Ching-Chih
authors.initials: CC
authors.lastname: Lee
authors.affiliation: School of Medicine, Tzu Chi University, Hualian, Taiwan, R.O.C.|Department of Radiation Oncology, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.
authors.forename: Hon-Yi
authors.initials: HY
authors.lastname: Lin
authors.affiliation: Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi, Taiwan, R.O.C.|Division of Hematology-Oncology, Department of Internal Medicine, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.
authors.forename: Szu-Chin
authors.initials: SC
authors.lastname: Li
authors.affiliation: School of Medicine, Tzu Chi University, Hualian, Taiwan, R.O.C.|Department of Otolaryngology, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.
authors.forename: Hsu-Chueh
authors.initials: HC
authors.lastname: Ho
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.
authors.forename: Chung-Lin
authors.initials: CL
authors.lastname: Hung
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Buddhist Dalin Tzu Chi Hospital, Chia-Yi, Taiwan, R.O.C.|School of Medicine, Tzu Chi University, Hualian, Taiwan, R.O.C.
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Su
mesh_terms: D001549:Benzamides; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects*; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects*; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology*; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011743:Pyrimidines; D011827:Radiation; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D001549:Benzamides; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D009025:Morpholines; D011743:Pyrimidines; D011838:Radiation-Sensitizing Agents; C585537:vistusertib; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D053148:Caspase 3