Abstract 1881: Screening of Rac1 and Cdc42 inhibitors as anti-metastatic compounds

Abstract Metastasis is responsible for 90% of cancer-related deaths and is a key cause of failure of cancer therapy. The development of effective targeted therapy to prevent and treat metastasis has been challenging. Homologous Rho GTPases Rac and Cdc42 are viable metastasis targets because they have a crucial role in the signaling pathways that regulate cell survival, proliferation, and migration, so dysregulation of these proteins leads to cancer progression and metastasis of diverse cancer types. Therefore, targeting these regulatory proteins results in anticancer and antimetastatic activity, as observed with our dual Rac/Cdc42 inhibitor, MBQ-167, in triple-negative breast cancer. MBQ-167 has an IC50 of ~100nM for Rac and Cdc42 activation inhibition and a GI50 of 130nM. MBQ-167 inhibits the binding of guanine nucleotides to Rac and Cdc42 with similar efficacy. The purpose of this study was to identify MBQ-167 derivatives with similar or greater efficacy and specificity, with a range of inhibitory mechanisms, that may be specific to the different guanine nucleotide exchange factors expressed in distinct cancer cell types. Currently, over 30 different compounds with potential Rac1 and Cdc42 inhibitory activity are being evaluated. So far, some of the evaluated compounds have shown comparable GI50 values to MBQ-167 in metastatic breast cancer cell lines. From this screening, CPV-337 was selected as a compound with a GI50 of ~55nM and ~70% Rac activation inhibition at 50nM, therefore being 2X more effective than our leading compound MBQ-167. However, evaluation of CPV-337 in the viability of the MCF-10 non-tumorigenic epithelial cell line demonstrated a GI50 of ~63nM, which is similar to that of breast cancer cells. Therefore, CPV-337 may have cytotoxic effects on breast cancer. We are continuing to screen the library of MBQ-167 derivatives in breast, pancreatic, lung, and prostate cancer cell lines. Citation Format: Jessica Colón González, María C. Santa María Fuentes, Cornelis Vlaar, Suranganie Dharmawardhane. Screening of Rac1 and Cdc42 inhibitors as anti-metastatic compounds 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 1881.