Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
Yonsei Med J. 2022 Jan;63(1):16-25. doi: 10.3349/ymj.2022.63.1.16.
Tumor radioresistance and dose-limiting toxicity restrict the curative potential of radiotherapy, requiring novel approaches to overcome the limitations and augment the efficacy. Here, we investigated the effects of signal transducer and activator of transcription 3 (STAT3) activation and autophagy induction by irradiation on antiapoptotic proteins and the effectiveness of the BH3 mimetic ABT-737 as a radiosensitizer using K-ras mutant non-small cell lung cancer (NSCLC) cells and a Kras:p53 mouse (KP mouse) model.
A549 and H460 cells were irradiated, and the expression of Bcl-2 family proteins, JAK/STAT transcriptional pathway, and autophagic pathway were evaluated by immunoblotting. The radiosensitizing effects of ABT-737 were evaluated using A549 and H460 cell lines with clonogenic assays and also by a KP mouse model with microcomputed tomography and immunohistochemistry.
In A549 and H460 cells and mouse lung tissue, irradiation-induced overexpression of the antiapoptotic molecules Bcl-xL, Bcl-2, Bcl-w, and Mcl-1 through JAK/STAT transcriptional signaling induced dysfunction of the autophagic pathway. After treatment with ABT-737 and exposure to irradiation, the number of surviving clones in the cotreatment group was significantly lower than that in the group treated with radiation or ABT-737 alone. In the KP mouse lung cancer model, cotreatment with ABT-737 and radiation-induced significant tumor regression; however, body weight changes in the combination group were not significantly different, suggesting that combination treatment did not cause systemic toxicity.
These findings supported the radiosensitizing activity of ABT-737 in preclinical models, and suggested that clinical trials using this strategy may be beneficial in K-ras mutant NSCLC.
肿瘤放射抵抗和剂量限制毒性限制了放射治疗的疗效，需要新的方法来克服这些限制并提高疗效。在这里，我们研究了信号转导子和转录激活子 3（STAT3）激活以及照射诱导的自噬对抗凋亡蛋白的影响，以及 BH3 模拟物 ABT-737 作为放射增敏剂在 K-ras 突变非小细胞肺癌（NSCLC）细胞和 Kras:p53 小鼠（KP 小鼠）模型中的有效性。
用 A549 和 H460 细胞照射，并用免疫印迹法评估 Bcl-2 家族蛋白、JAK/STAT 转录途径和自噬途径的表达。用 A549 和 H460 细胞系进行集落形成实验和 KP 小鼠模型进行微计算机断层扫描和免疫组织化学评估 ABT-737 的放射增敏作用。
在 A549 和 H460 细胞和小鼠肺组织中，照射诱导的抗凋亡分子 Bcl-xL、Bcl-2、Bcl-w 和 Mcl-1 的过表达通过 JAK/STAT 转录信号诱导自噬途径功能障碍。在用 ABT-737 处理并暴露于照射后，共处理组中存活克隆的数量明显低于单独用照射或 ABT-737 处理的组。在 KP 小鼠肺癌模型中，ABT-737 和放射联合治疗可显著诱导肿瘤消退；然而，联合组的体重变化没有显著差异，表明联合治疗不会引起全身毒性。
这些发现支持了 ABT-737 在临床前模型中的放射增敏活性，并表明使用该策略的临床试验可能对 K-ras 突变 NSCLC 有益。
