Abstract 586: Development of a novel pan-chemokine receptor inhibitor as therapeutic for breast cancer

Abstract The interaction of chemokines and their cognate receptors (CCRs) forms a key signaling network dedicated to promoting an inflammatory tumor microenvironment (TME), leukocyte recruitment and activation, angiogenesis, and growth in all stages of various cancers. Aberrant expressions of chemokines and CCRs are found to correlate with immunosuppression, metastasis, drug resistance, and poor prognosis in breast cancer patients. Several specific inhibitors for chemokines or CCRs are currently tested in clinical trials of multiple cancers. To date, no pan-CCR inhibitor has been developed as a cancer therapy, which is expected to have more clinical advantages than the agent with specificity for a single CCR. We collaborated with Dr. Filip Fratev's team (Micar21, Bulgaria) to develop potent pan-CCR inhibitors for breast cancer. By performing a virtual screen of 4 million compounds based on the analyses of Pharmacophore-based Docking, Induced-fit Docking, Molecular Dynamics, and Metadynamics, a novel pan-CCR inhibitor, SSFF-02, was identified, which showed strong inhibitory activities against CCR1, 3, 5. We tested SSFF-02 in xenografts bearing tumors derived from mouse breast cancer cell line 4T1. The treatments of SSFF-02 (5, 30, and 150 mg/kg) inhibited tumor growth on day 31 and significantly diminished the metastasis in the lung, liver, and ribs. We further examined the levels of serum INF-γ and 26 crucial cytokines and chemokines in the mice treated with SSFF-02 and the control group by enzyme-linked immunosorbent assay (ELISA) and chemokine array assay (RayBiotech). The SSFF-02-treated mice showed significant decreases in serum INF-γ and increases in CXCL5, CCL9, and CCL12. These data suggest that SSFF-02 can module the TME in breast cancer xenografts. The total mRNA of tumors collected from 4T1 xenografts have been harvested and are currently subjected to RNA sequencing (RNAseq) to characterize the chemokine-associated signature of breast cancer in response to SSFF-02. Furthermore, our MTT assays in human triple-negative breast cancer cell lines (MDA-MB-231, MDA-MB-468, Hs578T, and BT-20) and the hormone-dependent MCF7 cell line showed that 25 mM SSFF-02 significantly decreased over 50% of cell viabilities in all tested lines. Matrigel invasion assay demonstrated that the treatment of 5 or 10 mM SSFF-02 inhibited more than 60% of cancer cell migration in all lines. Our studies show that SSFF-02 is a promising targeted therapeutic and immune modulator for metastatic breast cancer. This study provides a foundation to pre-clinically develop SSFF-02 as therapeutics for breast cancer and other inflammatory cancers, such as lung, colorectal, and melanoma, with documented aberrant chemokine signaling. Citation Format: Mariana Grigoruta, Filip Fratev, Yong Qin. Development of a novel pan-chemokine receptor inhibitor as therapeutic for breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 586.