Abstract 674: Novel anti-cancer small molecule targeting the protein regulator of cytokinesis pathway

Abstract Aberrant migration and proliferation of cancer cells are the hallmark of metastatic tumors. Protein Regulator of Cytokinesis 1 (PRC1) is a scaffold protein that regulates metabolic pathways of cancer cell proliferation, survival, and metastasis. BKT300 is a small molecule (MW 399.33, C22H25NO6), that selectively inhibits the migration and survival of hematological and solid cancer cells. BKT300 inhibits, at high affinity, both actin and microtubule formation and organization leading to G2/M cell cycle arrest, mitotic catastrophe, and apoptosis through the caspase 3 pathway. These effects are selective to cancer cells and were not observed on normal cells. BKT300 was found to arrest PRC1 in a phosphorylated form at position T481, down regulates the expression of CDC25C and up regulate p21. Suppression of PRC1 using SiRNA ablation inhibited BKT300 induced apoptosis on several tumor cell lines and inhibited the effect of BKT300 on G2M cell cycle arrest. Furthermore, using Biacore SPR, microscale thermophoresis (MST), and ELISA assays we were able to demonstrate the direct binding of BKT300 to PRC1. Beyond its single agent activity, BKT300 was shown to synergize with standard of care (SoC) treatments, including anti PD-1 immunotherapy, BCL-2 inhibitor (Ventoclax), topoisomerase I inhibitor (Irinotecan) topoisomerase II inhibitor (Doxorubicin), anti-metabolite Fluorouracil (5-FU) and alkylating agent (Temozolomide). BKT300 has a remarkable safety profile when administered at high doses to mice rats, minipigs and non-human primates. Treatment with BKT300 showed almost no effects on hematopoiesis and biochemistry in doses far higher than the affective ones. The in-vivo activity of BKT300 was demonstrated in multiple Xenograft, Syngeneic and PDX models in mice. In-vivo treatment with BKT300 resulted in preventive (small tumors) as well as therapeutic (large tumors) activity in triple negative breast cancer (TNBC) xenograft, MDA-MB-453 and MDA-MB-468 models leading to over then 70%-90% reduction in tumor size following one to two treatments cycles. Similar results were obtained using PDX models derived from patients with Colon, Ovarian and Pancreatic cancer. BKT300 is a novel, first in class, targeted anti-cancer treatment that inhibits the activity of the scaffold protein PRC1. BKT300 is expected to provide a new treatment option to, the high unmet medical need of, advanced difficult to treat cancers, specifically ones that overexpress PRC1 and CDC25C. Citation Format: Amnon Peled, Michal Abraham, Hanna Wald, Rakefet Rosenfeld, Orly Eizenberg, Arnon Aharon. Novel anti-cancer small molecule targeting the protein regulator of cytokinesis pathway [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 674.