Abstract 1994: Drug-induced cancer cell secretome promotes resistance in colon cancer

Abstract Colorectal cancer (CRC) is the third most common cancer in the world, with a projection of increased lethality in the upcoming years. Adjuvant chemotherapy with biological agents is the most practiced standard of care today. However, patients with metastatic CRC (mCRC) do not benefit from the wide range of therapies available for CRC, which either owe to unresectability or co-morbidity or more importantly resistance to therapy. 5-fluorouracil (5-FU) combined with leucovorin, oxaliplatin, or irinotecan (FOLFOX or FOLFIRI) has been routinely employed as the first-line therapy in colon cancer, but patients often develop resistance to 5-FU. Additionally, tumor cell dormancy plays a major role in tumor relapse which leads to poor prognosis in the patients. Despite many advances, the understanding of therapy-induced resistance is still in its infancy. Here, we show that 5-FU-induced tumor cell secretome helps in the outgrowth and metastasis of 5-FU-resistant clones in colon cancer. We used parental and 5-FU-resistant colon cancer cell lines, and transgenic zebrafish embryos to test the hypothesis and perform the colon cancer cell-based functional assays. We observed that 5-FU resistant (5-FU-R) colon cancer cells showed an increase in proliferation and survival when cultured with the secretome of 5-FU exposed colon cancer cells compared to the DMSO-induced secretome. Interestingly, we also noted elevated migration and invasion in the 5-FU-R colon cancer cells exposed to 5-FU-induced secretome compared to the DMSO counterpart. Additionally, in zebrafish xenograft, we found that 5-FU-R colon cancer cells cultured with 5-FU-induced secretome showed higher tail-vein metastatic burden compared to the 5-FU-R cells cultured with DMSO-induced secretome. This provides a background to further study in detail the therapy-induced resistance as well as dormancy in colorectal cancer which will help to develop approaches to prevent or reverse chemoresistance in patients who receive systemic therapy for mCRC. Citation Format: Shakti Ranjan Satapathy, Souvik Ghatak, Anita Sjölander. Drug-induced cancer cell secretome promotes resistance in colon cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 1994.