Abstract A116: Targeting the Wnt-5a signaling pathway as a novel anti-metastatic therapy

Abstract Most current anti-cancer therapeutic drugs are targeting the proliferation and/or survival of cancer cells while very few drugs are aimed at specifically targeting the dissemination process. Several reports have demonstrated that low-levels or lack of Wnt-5a protein expression in primary breast-, colon-, and prostate cancer tissues correlates with shortened patient recurrence-free survival and overall survival pointing to a biological role of Wnt5a signaling in the dissemination process of cancer cells. The Wnt5a ligand mediates its effects vid interaction with G-protein coupled Frizzled receptors and tyrosine-kinase coupled receptors such as ROR1 and ROR2. Therefore, we developed two peptides, one being a Wnt-5a agonist (Foxy-5) and one being a Wnt-5a antagonist (Box-5). The Foxy-5 is a formylated Wnt5a-derived hexapeptide that mimics the ability of the Wnt-5a molecule to impair cancer cell migration in vitro and significantly reduces the formation of distant metastases in vivo in mouse models of breast- and prostate cancer. In addition, a 4-week toxicology study in rats and dogs with a final dose well exceeding the dose previously used in the mouse models showed no drug-induced toxic reactions.Based on all these pre-clinical data we initiated a clinical phase 1 study with the primary objective to evaluate the safety and tolerability of Foxy-5. All eligible patients are pre-screened for Wnt-5a immunoreactivity in archival tumor tissue and from dose level 7 and onwards only patients with negative or low level Wnt5a expressing metastatic breast-, colon-, or prostate cancer are enrolled in the study. This study has currently recruited cohorts 1-7 without reaching MTD and the final recruitment for the last dose level (dose level 8) is ongoing. Clinical trial information: NCT02020291. This study will be finalized during early fall 2015 and followed by a phase 1b study which will continue dose escalation but with a specific focus on determining the Biological Active Dose (BAD) since Foxy-5 does not possess anti-proliferative activities and is therefore not expected to induce tumor regression. In contrast to breast, colon and prostate cancer, Wnt5a signaling promotes tumor progression in vitro in melanoma and gastric cancer. The antagonistic Wnt5a-derived peptide Box5 possesses the capacity to impair Wnt5a signaling and migration in melanoma cells. We are now performing additional pre-clinical experiments to enable us to test the in vivo effects of Box5 in a melanoma animal model. Future clinical development plans include a phase II study enrolling patients with stage III colorectal cancer and then add Foxy-5 to standard 5FU plus oxaliplatin adjuvant treatment. Citation Format: Tommy Andersson, Lena Axelsson, Purusottam Mohapatra, Chandra Prasad, Peter Grundtvig Soerensen, Morten Mau-Soerensen, Ulrik Lassen, Tine Molvadgaard, Ulla Buhl, Nils Brünner, Dorte Nielsen. Targeting the Wnt-5a signaling pathway as a novel anti-metastatic therapy. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A116.