Recombinant human growtb hormone reduces the radiotherapy induced apoptosis on colorectal cancer cells
- VernacularTitle:重组人生长激素减少人结肠癌细胞株放疗诱导的细胞凋亡
- Author:
Xiaoyu WU
1
;
Xue-Quan YAO
;
Fu-Kun LIU
;
Weisu LI
;
Zhe XU
;
Che CHEN
Author Information
1. 江苏省中医院
- Keywords:
Growth hormone;
Growth hormone receptor Colorectal cancer;
Radiotherapy resistance;
Apoptosis
- From:
Journal of Surgery Concepts & Practice
2009;14(4):411-414
- CountryChina
- Language:Chinese
-
Abstract:
Objective To test the effect of recombinant human growth hormone (rhGH) on the radiotherapy sensitivity of colorectal cancer cell line, and to explore its relationship with apoptosis. Methods Flow cytometry and immunofluorescence were used to detect growth hormone receptor(GHR) expression on 9 human colorectal cancer cell lines. The colony forming assay was performed to measure the post-radiotherapy colorectal cancer cell proliferation as an indicator of radiotherapy sensitivity. Flow cytometry (Annexin V-FITC staining) was used to detect the radiotherapy induced apoptosis; Westem blot was performed to detect the phosphorylated Akt level within the same cell lines. Results HCT-8 GHR positive expression cell and LoVo GHR negative expression cells were selected for further studies. The colony formation rate was significantly enhanced in HCT-8 cells pre-incubated with thGH as compared to the radiotherapy group ceUs and in a dose dependent manne(0-100 mg/L); under high doses (8 Gy), this effect was more dramatic (52.1±2.9 vs 21.0±2.7, P<0.001). thGH pre-incubation also reduced radiotherapy induced HCT-8 cell apoptosis (P<0.05). When GHR was blocked with neutralizing antibodies, this protective effect was eliminated. By contrast, thGH pre-incubation did not change the colony formation rate in GHR negative expression LoVo cells. GH rapidly induced Akt phosphorylation in HCT-8 cells by GH/GHR signaling, and this effect was blocked by PI-3 kinase inhibitor. Conclusions The protective effect of GH on colorectal cancer cells may occur after radiotherapy exposured by GHR, which is related to the reduction of apotosis.
