title: Silencing of FANCD2 enhances the radiosensitivity of metastatic cervical lymph node-derived head and neck squamous cell carcinoma HSC-4 cells.
abstract: Fanconi anemia complementation group D2 (FANCD2) is involved in the key steps of the Fanconi anemia (FA) pathway, which plays a role in the repair of DNA crosslink damage. However, the role of FANCD2 during radiotherapy for head and neck squamous cell carcinoma (HNSCC) is unclear. In this study, the HNSCC cell line HSC-4 was used. Western blotting was used to evaluate the expression of the FANCD2 in HSC-4 cells. We investigated the impact of FANCD2 on the radiosensitivity of HSC-4 cells in vitro and in vivo. TUNEL, western blotting and immunohistochemistry were used to analyze the apoptosis and proteins involved in apoptosis-related pathways after radiotherapy to investigate the relevant mechanism. The present study showed that shRNA interference could effectively and stably silence FANCD2 expression in HSC-4 cells. In vitro, the silencing of FANCD2 inhibited cell proliferation, decreased the survival rate, increased apoptosis and induced S phase arrest in HSC-4 cells after radiotherapy. In vivo, the silencing of FANCD2 could prolong the tumor-forming time and slow tumor growth. In addition, the tumor volume was significantly reduced, the weight was deceased, and the tumor inhibition rate was increased after radiotherapy. TUNEL showed that the silencing of FANCD2 significantly increased apoptosis in HSC-4 cells induced by radiotherapy. Both in vitro and in vivo esperiments revealed that the expression of the Bax and p-p38 proteins in HSC-4 cells, in which FANCD2 had been silenced, was increased after radiotherapy, whereas the expression of the p38 and Bcl2 proteins was decreased. Our results suggested that the silencing of FANCD2 enhanced the radiosensitivity of HSC-4 cells, and its mechanism involves the activation of the p38 MAPK signaling pathway and the regulation of the expression of Bax and Bcl2 proteins. This study provides a novel candidate target for HNSCC therapy.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Hua-Jun
authors.initials: HJ
authors.lastname: Feng
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Yi-Lin
authors.initials: YL
authors.lastname: Bao
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Zhuo-Ping
authors.initials: ZP
authors.lastname: Liang
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Fei-Peng
authors.initials: FP
authors.lastname: Zhao
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Sheng-En
authors.initials: SE
authors.lastname: Xu
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Chong
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, P.R. China.
authors.forename: Gang
authors.initials: G
authors.lastname: Qin