DNA replication stress and mitotic catastrophe mediate sotorasib addiction in KRASG12C-mutant cancer

• Published in: Journal of biomedical science Vol. 30; no. 1; pp. 1 - 18
• Main Authors: Chiou, Li-Wen, Chan, Chien-Hui, Jhuang, Yu-Ling, Yang, Ching-Yao, Jeng, Yung-Ming
• Format: Journal Article
• Language: English
• Published: Basel BioMed Central Ltd 29.06.2023; BioMed Central; BMC
• Subjects: Addictions; Analysis; Annexin V; Apoptosis; Bioassays; Cancer; Cancer therapies; Care and treatment; Caspase; Cell culture; Cell cycle; Cell growth; Cell viability; Clinical trials; Comet assay; Cyclin-dependent kinase inhibitor p21; Damage; Deoxyribonucleic acid; DNA; DNA biosynthesis; DNA damage; DNA replication; Drug addiction; Drug approval; Drug resistance; Drug withdrawal; Flow cytometry; Genetic aspects; Growth factors; Health aspects; Hyperactivity; Immunofluorescence; Iodides; Kinases; KRAS; Lung cancer; Lung cancer, Non-small cell; MAP kinase; Mitosis; Mitotic catastrophe; Mutants; Non-small cell lung carcinoma; Pancreatic cancer; Propidium iodide; Protein kinases; Proteins; Replication; Replication stress; Sarcoma; Scientific equipment and supplies industry; Small cell lung carcinoma; Sotorasib; Substance abuse; Tumor cell lines; Withdrawal; Xenotransplantation; United States; United States > US; Taiwan
• ISSN: 1423-0127; 1021-7770; 1423-0127
• DOI: 10.1186/s12929-023-00940-4

Background Sotorasib is the first KRAS.sup.G12C inhibitor approved by the US Food and Drug Administration for treating KRAS.sup.G12C-mutant non-small-cell lung cancer (NSCLC). Clinical trials on the therapeutic use of sotorasib for cancer have reported promising results. However, KRAS.sup.G12C-mutant cancers can acquire resistance to sotorasib after treatment. We incidentally discovered that sotorasib-resistant (SR) cancer cells are addicted to this inhibitor. In this study, we investigated the mechanisms underlying sotorasib addiction. Methods Sotorasib-resistant cells were established using KRAS.sup.G12C-mutant pancreatic cancer and NSCLC cell lines. Cell viability in the presence or absence of sotorasib and in combination with multiple inhibitors was assessed through proliferation assay and annexin V/propidium iodide (PI) flow cytometry assays. The mechanisms underlying drug addiction were elucidated through 5-bromo-2'-deoxyuridine (BrdU) incorporation assay, immunofluorescence staining, time-lapse microscopy, and comet assay. Furthermore, a subcutaneous xenograft model was used to demonstrate sotorasib addiction in vivo. Results In the absence of sotorasib, the sotorasib-resistant cells underwent p21.sup.Waf1/.sup.Cip1-mediated cell cycle arrest and caspase-dependent apoptosis. Sotorasib withdrawal resulted in robust activation of mitogen-activated protein kinase (MAPK) pathway, inducing severe DNA damage and replication stress, which activated the DNA damage response (DDR) pathway. Persistent MAPK pathway hyperactivation with DDR exhaustion led to premature mitotic entry and aberrant mitosis, followed by micronucleus and nucleoplasmic bridge formation. Pharmacologic activation of the MAPK pathway with a type I BRAF inhibitor could further enhance the effects of sotorasib withdrawal on sotorasib-resistant cancer cells both in vitro and in vivo. Conclusions We elucidated the mechanisms underlying the sotorasib addiction of cancer cells. Sotorasib addiction appears to be mediated through MAPK pathway hyperactivity, DNA damage, replication stress, and mitotic catastrophe. Moreover, we devised a therapeutic strategy involving a type I BRAF inhibitor to strengthen the effects of sotorasib addiction; this strategy may provide clinical benefit for patients with cancer. Keywords: Sotorasib, Drug addiction, KRAS, Replication stress, Mitotic catastrophe