Griffin Daryl, Carson Robbie, Moss Debbie, Sessler Tamas, Lavin Deborah, Tiwari Vijay K, Karelia Shivaali, Kennedy Richard, Savage Kienan I, McDade Simon, Carie Adam, Pankovich Jim, Bazett Mark, Van Schaeybroeck Sandra
Patrick G. Johnston Centre for Cancer Research, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom.
Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark.
Mol Cancer Res. 2024 Dec 3;22(12):1088-1101. doi: 10.1158/1541-7786.MCR-24-0151.
Patients with class I V600EBRAF-mutant (MT) colorectal cancer exhibit a poor prognosis, and their response to combined anti-BRAF/EGFR inhibition remains limited. An unmet need exits for further understanding the biology of V600EBRAFMT colorectal cancer. We used differential gene expression of BRAFWT and MT colorectal cancer cells to identify pathways underpinning BRAFMT colorectal cancer. We tested a panel of molecularly/genetically subtyped colorectal cancer cells for their sensitivity to the unfolded protein response (UPR) activator BOLD-100. To identify novel combination strategies for BOLD-100, we performed RNA sequencing and high-throughput drug screening. Pathway enrichment analysis identified significant enrichment of the UPR and DNA repair pathways in BRAFMT colorectal cancer. We found that oncogenic BRAF plays a crucial role in mediating the response to BOLD-100. Using a systems biology approach, we identified V600EBRAFMT-dependent activation of the replication stress response kinase ataxia telangiectasia and Rad3-related (ATR) as a key mediator of resistance to BOLD-100. Further analysis identified acute increases in BRAFMT-dependent-reactive oxygen species levels following treatment with BOLD-100, which promoted ATR/CHK1 activation and apoptosis. Furthermore, activation of reactive oxygen species/ATR/CHK1 following BOLD-100 was mediated through the AhR transcription factor and CYP1A1. Importantly, pharmacological blockade of this resistance pathway with ATR inhibitors synergistically increased BOLD-100-induced apoptosis and growth inhibition in BRAFMT models. These results highlight a possible novel therapeutic opportunity for BRAFMT colorectal cancer. Implications: BOLD-100 induces BRAFMT-dependent replication stress, and targeted strategies against replication stress (e.g., by using ATR inhibitors) in combination with BOLD-100 may serve as a potential novel therapeutic strategy for clinically aggressive BRAFMT colorectal cancer.
I 类 V600E BRAF 突变（MT）结直肠癌患者预后较差，且他们对 BRAF/EGFR 联合抑制的反应仍然有限。目前仍存在未满足的需求，即需要进一步了解 V600E BRAF MT 结直肠癌的生物学特性。我们利用 BRAF 野生型（WT）和 MT 结直肠癌细胞的差异基因表达来确定支撑 BRAF MT 结直肠癌的信号通路。我们测试了一组分子/基因分型的结直肠癌细胞对未折叠蛋白反应（UPR）激活剂 BOLD-100 的敏感性。为了确定 BOLD-100 的新型联合策略，我们进行了 RNA 测序和高通量药物筛选。通路富集分析确定了 UPR 和 DNA 修复通路在 BRAF MT 结直肠癌中显著富集。我们发现致癌性 BRAF 在介导对 BOLD-100 的反应中起关键作用。使用系统生物学方法，我们确定 V600E BRAF MT 依赖性激活复制应激反应激酶共济失调毛细血管扩张症和 Rad3 相关蛋白（ATR）是对 BOLD-100 耐药的关键介质。进一步分析发现，用 BOLD-100 治疗后，BRAF MT 依赖性活性氧水平急性升高，这促进了 ATR/CHK1 激活和细胞凋亡。此外，BOLD-100 后活性氧/ATR/CHK1 的激活是通过芳烃受体（AhR）转录因子和细胞色素 P450 1A1（CYP1A1）介导的。重要的是，在 BRAF MT 模型中，用 ATR 抑制剂对该耐药通路进行药理学阻断可协同增加 BOLD-100 诱导的细胞凋亡和生长抑制。这些结果突出了 BRAF MT 结直肠癌可能的新型治疗机会。启示：BOLD-100 诱导 BRAF MT 依赖性复制应激，针对复制应激的靶向策略（例如使用 ATR 抑制剂）与 BOLD-100 联合使用可能成为临床上侵袭性 BRAF MT 结直肠癌的潜在新型治疗策略。
