ORIGINAL RESEARCH article
Front. Pharmacol.
Sec. Experimental Pharmacology and Drug Discovery
Volume 16 - 2025 | doi: 10.3389/fphar.2025.1568339
CS-6-induced p62 accumulation exacerbates DNA damage in colorectal cancer
Provisionally accepted
Yitong Gong1
Menghan Dong2Xiaofei Feng3Naiyu Zhang2Xuehui Cui2Liushuyue Wang2
Chiu-fai Kuok4*
Jiang Qing Ling2*
Sixue Bi2*- 1Ludong University, Yantai, Shandong Province, China
- 2Binzhou Medical University, 烟台市, China
- 3Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong Province, China
- 4Macao Polytechnic University, Macau, Macao, SAR China
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Gamabufotalin (CS-6), a bufadienolide derived from Chansu, has been reported to exhibit anti-tumor effects in various cancers, including glioblastoma, non-small cell lung cancer, and breast cancer. However,its role in colorectal cancer (CRC) remains unexplored. In our study, we found that CS-6 treatment significantly inhibited CRC SW620 and DLD1 cell viability and colony formation in vitro. Furthermore, CS-6 treatment-induced DNA damage and cell cycle arrest in SW620 and DLD1 cells. Proteomics analysis and the western blot assay revealed that CS-6 treatment upregulated p62 expression, an autophagic substrate involved in the regulation of DNA double-strand damage repair. Knockdown of p62 in this study significantly alleviated CS-6-induced DNA damage and the downregulation of cyclin expression in SW620 and DLD1 cells. Additionally, the results indicated increased expression of microtubule-associated protein I/II light chain 3II (LC3II) and reduced binding between B-cell lymphoma-2 (Bcl2) and beclin-1, suggesting that CS-6 treatment activated early-stage autophagy in CRC cells. However, inhibition of late-stage autophagy and autophagy-related protein 5 (ATG5) with chloroquine and si-ATG5, respectively, further indicated that CS-6-induced autophagy defects led to p62 accumulation, exacerbated cell proliferation inhibition, and aggravated DNA damage. Intraperitoneal injection with CS-6 inhibited tumor growth in nude mice with colorectal cancer, and promoted the protein expression of phosphorylated H2A histone family member X (γH2AX), p62, phosphorylated Ataxia-telangiectasia mutated kinase (p-ATM) and LC3 I/II. In conclusion, this study suggests that CS-6 may exert its anti-tumor effects in CRC by inducing autophagy defects, resulting in p62 accumulation and DNA damage in vitro and in vivo.
Keywords: Gamabufotalin (CS-6), colorectal cancer (CRC), DNA Damage, p62, Autophagy
Received: 30 Jan 2025; Accepted: 16 Apr 2025.
Copyright: © 2025 Gong, Dong, Feng, Zhang, Cui, Wang, Kuok, Ling and Bi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Chiu-fai Kuok, Macao Polytechnic University, Macau, Macao, SAR China
Jiang Qing Ling, Binzhou Medical University, 烟台市, China
Sixue Bi, Binzhou Medical University, 烟台市, China
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