title: SHP-1 overexpression increases the radioresistance of NPC cells by enhancing DSB repair, increasing S phase arrest and decreasing cell apoptosis.
abstract: The present study aimed to investigate the influence of SHP-1 on the radioresistance of the nasopharyngeal carcinoma (NPC) cell line CNE-2 and the relevant underlying mechanisms. The human NPC cell line CNE-2 was transfected with a lentivirus that contained the SHP-1 gene or a nonsense sequence (referred to as LP-H1802Lv201 and LP-NegLv201 cells, respectively). Cells were irradiated with different ionizing radiation (IR) doses. Cell survival, DNA double-strand breaks (DSBs), apoptosis, cell cycle distribution, and the expression of related proteins were assessed using colony formation assay, immunofluorescent assays (IFAs), flow cytometry (FCM) and western blot analyses, respectively. Compared with the control (CNE-2 cells) and LP-NegLv201 cells, LP-H1802Lv201 cells were more resistant to IR. IFAs showed that IR caused less histone H2AX phosphorylation (γH2AX) and RAD51 foci in the LP-H1802Lv201 cells. Compared with the control and LP-NegLv201 cells, LP-H1802Lv201 cells showed increased S phase arrest. After IR, the apoptotic rate of the LP-H1802Lv201 cells was lower in contrast to the control and LP-NegLv201 cells. Western blot analyses showed that IR increased the phosphorylation of ataxia telangiectasia mutated (ATM) kinase, checkpoint kinase 2 (CHK2), ataxia telangiectasia and Rad3-related (ATR) protein, checkpoint kinase 1 (CHK1) and p53. In LP-H1802Lv201 cells, the phosphorylation levels of ATM and CHK2 were significantly increased while the p53 phosphorylation level was decreased compared to these levels in the control and LP-NegLv201 cells. Phosphorylation of ATR and CHK1 did not show significant differences in the three cell groups. Overexpression of SHP-1 in the CNE-2 cells led to radioresistance and the radioresistance was related to enhanced DNA DSB repair, increased S phase arrest and decreased cell apoptosis.
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Xiaofen
authors.initials: X
authors.lastname: Pan
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Mou
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Sha
authors.initials: S
authors.lastname: Liu
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Ziyi
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Meng
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Zhenwei
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.affiliation: Cancer Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China.
authors.forename: Gang
authors.initials: G
authors.lastname: Peng
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D064007:Ataxia Telangiectasia Mutated Proteins / Q000096:biosynthesis / Q000378:metabolism; D002277:Carcinoma; D059447:Cell Cycle Checkpoints / Q000528:radiation effects; D064447:Checkpoint Kinase 2 / Q000096:biosynthesis / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects; D006801:Humans; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000532:radiotherapy; D010766:Phosphorylation / Q000528:radiation effects; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000096:biosynthesis / Q000235:genetics*; D011836:Radiation Tolerance / Q000235:genetics*; D011839:Radiation, Ionizing
chemical_list: D064447:Checkpoint Kinase 2; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C578634:CHEK2 protein, human; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6