Du Hua-Qing, Wang Ying, Jiang Yao, Wang Chen-Han, Zhou Tao, Liu Hong-Yi, Xiao Hong
Department of Neuro-Psychiatric Institute, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China.
Oncol Rep. 2015 Jun;33(6):2807-14. doi: 10.3892/or.2015.3906. Epub 2015 Apr 8.
The present study was designed to investigate the relationship between tropomyosin 1 (TPM1) and radioresistance in human U251 cells. Radioresistant U251 (RR-U251) cells were established by repeated small irradiating injury. TPM1 levels in the U251 and RR-U251 cells were inhibited by transfection with TPM1-short hairpin RNA (shRNA) while overexpression was induced by treatment with pcDNA3.1‑TPM1. The radiosensitivity of the U251 and RR-U251 cells and the plasmid-transfected cells was evaluated by cell viability, migration and invasion assays. Cell apoptosis was also examined in vitro. The radiosensitivity of U251 xenografts was observed by tumor growth curve after radiotherapy in an in vivo experiment. Western blotting and immunohistochemistry were used to detect the level of TPM1 in vivo. The expression of TPM1 was significantly decreased in the RR-U251 cells, which may be correlated with the radioresistance of the glioma U251 cells. In the TPM1-silenced RR-U251 and TPM1-silenced U251 cells, cell viability, migration and invasion ability were significantly increased, and the rate of cell apoptosis was decreased. Consistent with these results, in the TPM1-overexpressing U251 and RR-U251 cells, cell viability, migration and invasion abilities were markedly decreased, and increased apoptosis was noted when compared to the control group. Tumor growth of the U251 xenografts was significantly inhibited following treatment with pcDNA3.1‑TPM1 combined with radiotherapy. Taken together, these results indicate that TPM1 may be one mechanism underlying radiation resistance, and TPM1 may be a potential target for overcoming the radiation resistance in glioma.
本研究旨在探讨原肌球蛋白1（TPM1）与人U251细胞放射抗性之间的关系。通过反复小剂量照射损伤建立放射抗性U251（RR-U251）细胞。用TPM1短发夹RNA（shRNA）转染抑制U251和RR-U251细胞中的TPM1水平，同时用pcDNA3.1-TPM1处理诱导其过表达。通过细胞活力、迁移和侵袭试验评估U251和RR-U251细胞以及质粒转染细胞的放射敏感性。还在体外检测细胞凋亡情况。在体内实验中，通过放疗后的肿瘤生长曲线观察U251异种移植瘤的放射敏感性。采用蛋白质免疫印迹法和免疫组织化学法检测体内TPM1水平。RR-U251细胞中TPM1的表达显著降低，这可能与胶质瘤U251细胞的放射抗性相关。在TPM1沉默的RR-U251和TPM1沉默的U251细胞中，细胞活力、迁移和侵袭能力显著增加，细胞凋亡率降低。与这些结果一致，在TPM1过表达的U251和RR-U251细胞中，与对照组相比，细胞活力、迁移和侵袭能力明显降低，凋亡增加。用pcDNA3.1-TPM1联合放疗后，U251异种移植瘤的肿瘤生长受到显著抑制。综上所述，这些结果表明TPM1可能是放射抗性的一种潜在机制，并且TPM1可能是克服胶质瘤放射抗性的一个潜在靶点。
