Abstract 6927: Novel ferrocene and naphthalene-based analogs block HRH1-signaling to inhibit colon cancer growth

Abstract Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide, with over 1.8 million incidences and 900, 000 deaths annually. CRC persists as a significant clinical challenge, detailing a 5-year survival rate of 14% for patients with distant metastases. CRC exhibits high genetic heterogeneity, which supplements a rich mutational landscape that gives rise to aggressive phenotypes. Therefore, there is a pressing need to identify novel and effective therapeutics to target CRC alongside identifying niche molecular pathways that contribute to pathogenesis. Here, we report the identification and formulation of novel histamine receptor 1 (HRH1) antagonists that inhibit CRC cell growth. Ferrocene (Fc) analogs are interesting due to their excellent lipophilicity, redox nature and anticancer activity. We synthesized a series of Fc and naphthalene-based compounds and tested them against colorectal cancer (CRC) cells HCT-116 and DLD-1. Compounds C10 and C12 inhibited the growth of CRC cells (IC50 = 0.5-1 mM), colony formation and induced apoptosis by downregulating bcl2 and mcl1 levels. We identified that both C10 and C12 bind to histamine receptor 1 (HRH1) using molecular docking studies. HRH1 is overexpressed in CRC cells and tissues compared to noncancerous colonic tissue. Further, histamine treatment activated ERK and GSK3β phosphorylation time-dependently in CRC cells, suggesting the receptor's functionality. Moreover, preincubation of C10 and C12 with CRC cells inhibited histamine-induced ERK and GSK3β phosphorylation, suggesting that C10 and C12 block HRH1 to inhibit histamine signaling. Further, a cellular thermal shift assay (CETSA) showed protection from thermal denaturation in C10 and C12 treated groups, suggesting a protein stabilization and potential binding of C10 and C12 with HRH1. Finally, C10 and C12 treatment (20 mg/kg, i.p., once daily, 21 days) reduced tumor volume and weight in HCT116-xenograft growth in NSG mice. In conclusion, we discovered novel HRH1 antagonists to inhibit colon cancer growth. Citation Format: Affan Ahmad Ansari, Dileepkumar Veeragoni, Ahraar Azaz, Sangita Bhattacharya, Hindole Ghosh, Bernhard Biersack, Prasad Dandawate. Novel ferrocene and naphthalene-based analogs block HRH1-signaling to inhibit colon cancer growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6927.