目的：探讨低剂量辐射（LDR）与人端粒酶逆转录酶C末端多肽27（hTERTC27）过表达联合治疗对肺癌A549细胞增 殖和凋亡的影响，同时观察LDR与常规放疗（CONV-RT）结合的体内抑瘤效应。方法：将pEgr-hTERTC27质粒转染人非小细胞 肺癌A549及小鼠LLC肺癌（LLC）细胞，用G418筛选建立稳定表达C27的A549-C27细胞和LLC-C27细胞。细胞实验分为6组， 分别是CONV-RT（A549-Con）、低剂量照射（A549-Low）、C27（A549-C27）、常规剂量联合C27（A549-C27-Con）、低剂量照射联合 C27（A549-C27-Low）和对照（A549-Mock）组，其中Low组的辐照剂量仅为Con组的36%。MTT法检测各组细胞增殖活性，流式 细胞术检测各组细胞凋亡率。通过皮下种植建立LLC肺癌移植瘤小鼠模型，动物实验分组同细胞实验；记录各组小鼠肿瘤生长 情况，并检测各组肿瘤体积和质量，H-E染色观察各组移植瘤组织邻近肌肉浸润情况。结果：与A549-Mock比较，A549-Con和 A549-Low组细胞增殖活性均显著降低（均P < 0.01）；而且A549-C27-Con和A549-C27-Low组细胞增殖活性显著低于A549-C27 组（均P < 0.01）。与A549-Mock组比较，A549-Con组和A549-Low组细胞凋亡率均显著升高（均P < 0.01）；A549-C27、A549-C27- Con和A549-C27-Low组细胞凋亡率无显著差异（P > 0.05）。与未经照射治疗的荷瘤小鼠相比较，CONV-RT及LDR + CONV-RT 均可使荷瘤小鼠肿瘤质量显著降低（均P < 0.01）。此外，LDR + CONV-RT + C27组肿瘤质量显著减小，局部浸润减少（均P < 0.01）。 结论：LDR与CONV-RT相结合能够在降低辐射总剂量的同时达到与CONV-RT单独使用相似的非小细胞肺癌肿瘤抑制效果。 而且，LDR与C27多肽有协同抗肿瘤作用，两者同时使用能够使移植瘤局部浸润减少。

[Abstract] Objective: To investigate the effects of low-dose radiation (LDR) combined with human telomerase reverse transcriptase Cterminal polypeptide 27 (hTERTC27) overexpression on the proliferation and apoptosis of lung cancer A549 cells, and to observe the in vivo antitumor effects of LDR combined with C27. Methods: The pEgr-hTERTC27 plasmid was transfected into human non-small cell lung cancer (NSCLC) A549 cells and mouse Lewis lung carcinoma (LLC) cells. Cells stably expressing C27 (A549-C27 and LLC-C27) were screened by G418 selection. The cells were divided into six groups: conventional radiation (CONV-RT) group (A549-Con), LDR group (A549-Low), C27 group (A549-C27), CONV-RT combined with C27 group (A549-C27-Con), LDR combined with C27 group (A549-C27-Low), and control group (A549-Mock). The irradiation dose in LDR group was only 36% of CONV-RT group. MTT assay was used to detect cell proliferation, and flow cytometry was used to measure cell apoptosis. LLC cell-transplanted tumor model in mice was established through subcutaneous implantation, and the animal experiment groups were similar with cell experiments. Tumor growth, volume, and mass were recorded in each group. Muscle infiltration near the transplanted tumors was observed using H-E staining. Results: Compared with A549-Mock group, the proliferative activity of A549-Con and A549-Low group was significantly decreased (all P < 0.01). Furthermore, the proliferation activity of A549-C27-Con and A549-C27-Low cells was significantly lower than that of A549-C27 cells (all P < 0.01). Compared with A549-Mock, the apoptosis rates were significantly higher in A549-Con and A549-Low groups (P < 0.01); however, no significant difference in apoptosis rates were observed among A549-C27, A549-C27-Con and A549-C27-Low groups (all P > 0.05). In tumor-bearing mice, both CONV-RT and LDR significantly reduced tumor mass compared with unirradiated mice (all P < 0.01). In addition, the tumor mass and local infiltration were significantly reduced in both LLC-C27-Low and LLC-C27-Con groups. Conclusion: LDR combined with C27 achieves similar antitumor effects to CONV-RT alone while reducing the total radiation dose in NSCLC. Moreover, LDR and C27 peptide synergize in their anti-tumor effects, with their combination reducing local tumor infiltration in transplanted tumor models.

内蒙古自治区自然科学基金（No. 2021SHZR0996）；包头市青年创新人才项目资助