据报道,在非同源末端连接修复途径中抑制DNA依赖性蛋白激酶(DNA-PK)会增加癌细胞的辐射敏感性。我们最近报道了BR101801,PI3K-γ(γ)的新型三联抑制剂,delta(δ),和DNA-PK,在各种人类实体癌细胞和异种移植小鼠模型中,充当辐射诱导的DNA损伤的有效敏化剂。鉴于p53抑癌基因在放疗疗效中起着重要作用,在目前的研究中,我们使用等基因HCT116p53+/+和HCT116p53-/-人结直肠癌细胞系,重点研究了p53状态对BR101801诱导的放射增敏作用的影响.体外,HCT116p53+/+和HCT116p53-/-人结直肠癌细胞用1μMBR101801预处理24小时,然后暴露于电离辐射(IR)。然后是分析集落形成的方法,DNA损伤,细胞周期的变化,衰老,自噬,凋亡,和DNA损伤反应相关蛋白。构建异种移植小鼠模型以检查BR101801(50mg/kg,每天口服一次)和对体内肿瘤生长抑制作用的IR(2Gy×3天)。BR101801抑制HCT116p53+/+和HCT116p53-/-人结直肠癌细胞的细胞增殖并延长DNA损伤。BR101801和IR联合治疗强烈诱导G2/M期细胞周期停滞,凋亡,与单独IR治疗相比,HCT116p53-/-细胞的细胞衰老。此外,BR101801协同抑制HCT116p53-/-异种移植小鼠模型中的肿瘤生长。BR101801增强了HCT116人结直肠癌细胞的放射敏感性,无论其p53状态如何。此外,BR101801对IR诱导的细胞周期阻滞发挥了强大的协同作用,凋亡,和肿瘤生长抑制,甚至在耐放射性HCT116p53-/-细胞中。总的来说,这些发现为将BR101801与IR结合作为克服p53缺陷引起的放射抗性的新治疗策略提供了科学依据.
Inhibition of DNA-dependent protein kinase (DNA-PK) in the non-homologous end-joining repair pathway reportedly increases the radiation sensitivity of cancer cells. We have recently reported that BR101801, a novel triple inhibitor of PI3K-gamma (γ), delta (δ), and DNA-PK, functions as an efficient sensitizer of radiation-induced DNA damage in various human solid cancer cells and a xenograft mouse model. Given that the p53 tumor suppressor gene plays an important role in radiotherapeutic efficacy, in the current study, we focused on the impact of the p53 status on BR101801-induced radiosensitization using isogenic HCT116 p53+/+ and HCT116 p53-/- human colorectal cancer cell lines. In vitro, HCT116 p53+/+ and HCT116 p53-/- human colorectal cancer cells were pretreated with 1 μM BR101801 for 24 h before exposure to ionizing radiation (IR), followed by assays to analyze colony formation, DNA damage, cell cycle changes, senescence, autophagy, apoptosis, and DNA damage response-related proteins. Xenograft mouse models were constructed to examine the potential synergistic effects of BR101801 (50 mg/kg, orally administered once daily) and fractionated IR (2 Gy × 3 days) on tumor growth inhibition in vivo. BR101801 inhibited cell proliferation and prolonged DNA damage in both HCT116 p53+/+ and HCT116 p53-/- human colorectal cancer cells. Combined treatment with BR101801 and IR robustly induced G2/M phase cell cycle arrest, apoptosis, and cellular senescence in HCT116 p53-/- cells when compared with treatment with IR alone. Furthermore, BR101801 synergistically inhibited tumor growth in the HCT116 p53-/- xenograft mouse model. BR101801 enhanced the radiosensitivity of HCT116 human colorectal cancer cells regardless of their p53 status. Moreover, BR101801 exerted robust synergistic effects on IR-induced cell cycle arrest, apoptosis, and tumor growth inhibition, even in radioresistant HCT116 p53-/- cells. Overall, these findings provide a scientific rationale for combining BR101801 with IR as a new therapeutic strategy to overcome radioresistance induced by p53 deficiency.