Abstract 2071: Pre-clinical evidence for new camptothecin-peptide conjugates in the treatment of sortilin-positive colorectal cancers

Abstract

Abstract Limitations in current colorectal cancer (CRC) camptothecin (CPT)-based chemotherapy have mostly been attributed to low specificity and high systemic cytotoxic side effects. More effective therapies are therefore required to improve the clinical outcomes of patients with CRC. Here, we developed a selective and better anticancer drug delivery of CPT through conjugation to a peptide (TH19P01) that targets Sortilin (SORT1), a scavenging receptor expressed in various tumor tissues including CRC. In the current study, significant SORT1 expression was detected in various CRC cell lines as well as that of irinotecan analogs efflux pump (ABCG2) in LoVo and HT-29 cells. Considering this result, we used our proprietary peptide conjugation SORT1 technology to increase cell targeting selectivity and cell delivery efficacy of CPT analogs. Different peptide drug conjugates (PDCs) were generated linking the TH19P01 peptide to SN-38 (an irinotecan metabolite) or exatecan, which are two main CPT derivatives used in recent antibody drug conjugates (ADC) as payloads. In vitro, immunonofluorescent microscopy revealed that TH19P01 was rapidly internalized (<15 min) in a SORT1-positive human HT-29 CRC cell model. These PDCs also inhibited CRC cell proliferation at low nM concentrations (3-90 nM). In vivo, weekly administration of TH2101 (SN-38) and of TH2303 (exatecan) conjugates were well tolerated as they had little impact on mouse body weight but caused a more potent growth inhibition of the HT-29 CRC tumor xenograft model than did either unconjugated irinotecan or exatecan molecules. In fact, at their maximum tolerable dose, irinotecan and exatecan caused a tumor growth inhibition of only 48% and 45% whereas TH2101 and TH2303 inhibited the growth of HT-29 tumors by 83% and 91%, respectively. These results provide strong pre-clinical evidence for the future development of novel CPT PDCs therapeutics with targeting of SORT1-positive CRC cells. Citation Format: Sanjoy Das, Jean-Christophe Currie, Michel Demeule, Cyndia Charfi, Alain Zgheib, Amit Nayyar, Anh Minh Thao Nguyen, Bogdan Alexandru Danalache, Richard Beliveau, Christian Marsolais, Borhane Annabi. Pre-clinical evidence for new camptothecin-peptide conjugates in the treatment of sortilin-positive colorectal cancers [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 2071.