背景:端粒酶,通过保护受损的端粒和支持DNA损伤修复,有能力提高肿瘤细胞的抗辐射能力。因此,反过来,可能会损害放射治疗(RT)和放射免疫治疗的疗效。我们以前的研究表明,高选择性端粒酶抑制剂,BIBR1532具有增强非小细胞肺癌(NSCLC)的放射敏感性的潜力。在这项研究中,我们进一步探讨了BIBR1532对RT诱导的免疫激活的影响,并阐明了其潜在机制。
方法:生物信息分析,免疫荧光测定,蛋白质印迹试验,流式细胞术分析阐明BIBR1532联合放疗在NSCLC中的作用.脂质过氧化物的细胞内水平,谷胱甘肽,丙二醛,和Fe2+作为铁凋亡状态的指标。进行了体外和体内研究以检查抗肿瘤作用。
结果:我们的发现表明,BIBR1532与RT的汇合显着增强了体内和体外环境中cGAS-STING途径的激活,从而促进有效的抗肿瘤免疫反应。这些影响可以归因于两个关键过程。首先,电离辐射,在沉淀DNA双链断裂(DSB)中,促使肿瘤衍生的双链DNA(dsDNA)释放到细胞质中。随后,BIBR1532在RT后通过dsDNA扩增抗原呈递细胞的活化并激发cGAS-STING途径。其次,BIBR1532增强RT后NSCLC的铁凋亡反应,从而促进肿瘤细胞内未受约束的脂质过氧化和活性氧(ROS)水平升高。这最终导致线粒体应激和内源性线粒体DNA(mtDNA)释放到细胞质中,从而促进STING途径的激活和I型干扰素(IFN)相关的适应性免疫应答的诱导。
结论:本研究强调了BIBR1532作为一种有效和安全的放射增敏剂和放射免疫疗法增效剂的潜力,为NSCLC的治疗提供有力的临床前研究证据。
BACKGROUND: Telomerase, by safeguarding damaged telomeres and bolstering DNA damage repair, has the capacity to heighten the radioresistance of tumour cells. Thus, in turn, can compromise the efficacy of radiotherapy (RT) and radioimmunotherapy. Our previous studies have revealed that the highly selective telomerase inhibitor, BIBR1532, possesses the potential to enhance the radiosensitivity of Non-small cell lung cancer (NSCLC). In this study, we delve further into the impact of BIBR1532 on the immune activation induced by RT and elucidate the underlying mechanisms.
METHODS: Biological information analyses, immunofluorescence assays, western blot assays, flow cytometry analysis were conducted to elucidate the functions of the combination of BIBR1532 with radiotherapy in NSCLC. Intracellular levels of lipid peroxides, glutathione, malondialdehyde, and Fe2+ were measured as indicators of ferroptosis status. Both in vitro and in vivo studies were conducted to examine the antitumor effects.
RESULTS: Our findings indicate that the confluence of BIBR1532 with RT significantly augments the activation of the cGAS-STING pathway in both in vivo and in vitro settings, thereby fostering an effective anti-tumoral immune response. The effects can be ascribed to two key processes. Firstly, ionizing radiation, in precipitating DNA double-strand breaks (DSBs), prompts the release of tumour-derived double-stranded DNA (dsDNA) into the cytoplasm. Subsequently, BIBR1532 amplifies the activation of antigen-presenting cells by dsDNA post-RT and instigates the cGAS-STING pathway. Secondly, BIBR1532 enhances the ferroptosis response in NSCLC following RT, thereby promoting unrestrained lipid peroxidation and elevated levels of reactive oxygen species (ROS) within tumour cells. This ultimately leads to mitochondrial stress and the release of endogenous mitochondrial DNA (mtDNA) into the cytoplasm, thus facilitating the activation of the STING pathway and the induction of a type I interferon (IFN)-linked adaptive immune response.
CONCLUSIONS: This study underscores the potential of BIBR1532 as an efficacious and safe radiosensitizer and radioimmunotherapy synergist, providing robust preclinical research evidence for the treatment of NSCLC.