Abstract 529: Investigating the synergistic effect of milciclib and PD0325901 in colorectal cancer therapy

Abstract

Abstract Milciclib, characterized as a potent nanomolar inhibitor of multiple cyclin-dependent kinases, has recently emerged as a promising therapeutic agent in cancer treatment, particularly with its additional role as a spliceosome modulator. Our recent studies employing RNA sequencing technology revealed a comprehensive profile of Milciclib-induced transcriptional changes in colorectal cancer cells, identifying several key regulated pathways. In light of these findings, we explored a novel therapeutic strategy: combining Milciclib with specific inhibitors targeting pathways upregulated by Milciclib treatment. This hypothesis is based on the rationale that such a combination could exert a synergistic effect. We have assessed the efficacy of this combinational therapy and found that the combination of Milciclib and PD0325901 greatly potentiates the killing of colorectal cancer cells versus either treatment alone. PD0325901 has been extensively studied for its efficacy in targeting the MEK/ERK signaling pathway, a critical pathway in many cancers, including colorectal cancer. To further characterize the underlying molecular mechanisms contributing to the observed synergistic effect, we applied quantitative proteomic analysis of 8107 proteins in human colorectal cancer cells with the treatment of different doses of Milciclib and PD0325901 administered alone, or in combination. Our results demonstrate 49 proteins were significantly decreased in a dose-dependent manner, and that many of these proteins are key players regulating pathways associated with the cell cycle, apoptosis, gene expression, metabolism, WNT signaling, and the MEK/ERK signaling pathway. The discovery of the down-regulation of these proteins and pathways after treatment provides a molecular basis to elucidate the synergistic mechanism underlying Milciclib and PD0325901 combination therapy. In conclusion, our study establishes the combinatorial use of Milciclib and PD0325901 as a potential breakthrough in the treatment of colorectal cancer, offering a promising prospect for enhancing future patient outcomes. Citation Format: Xinyu Pei, Anh Nguyen, Hannah Neiger, Wenjia Wang, William Bautista, Lily Wang, Alvan Cai, Valerie A. Gerriets, John K. Cusick, Yihui Shi. Investigating the synergistic effect of milciclib and PD0325901 in colorectal cancer therapy [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(6_Suppl):Abstract nr 529.