Justin Anthony Ripper

Euodenine A: A Small-Molecule Agonist of Human TLR4

A small-molecule natural product, euodenine A (1), was identified as an agonist of the human TLR4 receptor. Euodenine A was isolated from the leaves of Euodia asteridula (Rutaceae) found in Papua New Guinea and has an unusual U-shaped structure. It was synthesized along with a series of analogues that exhibit potent and selective agonism of the TLR4 receptor. SAR development around the cyclobutane ring resulted in a 10-fold increase in potency. The natural product demonstrated an extracellular site of action, which requires the extracellular domain of TLR4 to stimulate a NF-κB reporter response. 1 is a human-selective agonist that is CD14-independent, and it requires both TLR4 and MD-2 for full efficacy. Testing for immunomodulation in PBMC cells shows the induction of the cytokines IL-8, IL-10, TNF-α, and IL-12p40 as well as suppression of IL-5 from activated PBMCs, indicating that compounds like 1 could modulate the Th2 immune response without causing lung damage.

Abstract 4029: BL-011256 is a novel VEGFR3 selective inhibitor, which suppresses tumor lymphatics and lymph node metastasis in an animal model of melanoma

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA The role of VEGFR3 in lymphangiogenesis has been well established. Targeting VEGFR3 has been shown to curtail tumor progression mediated via lymphatic dissemination. More recently VEGFR3 was shown to play an important role in the mediation of tumor-induced immune cell tolerance. We have identified BL-011256, a novel inhibitor of VEGFR3 that exhibits 17-fold selectivity over VEGFR2 and a narrow tyrosine kinase inhibition spectrum. A 7-day b.i.d repeat oral dose study showed that BL-011256 is well tolerated in mice. Mouse plasma exposure experiments demonstrated that BL-011256 attains free drug plasma concentration levels that exceed the concentration required for IC50 activity on VEGFR3 in vitro but are considerably lower than the in vitro IC50 required for activity on VEGFR2. In the B16F10 mouse melanoma model, animals bearing melanoma tumors displayed considerably attenuated signs of tumor progression when treated with BL-011256. BL-011256 caused a 70% reduction in primary lesion growth and a 50% reduction in metastasis to the draining lymph node. Furthermore, BL-011256 was active in reducing the number of satellite in-transit metastases. Immunohistochemical whole mount analyses on ears with primary tumor lesions derived from BL-011256 treated and vehicle-treated mice using Lyve-1 for the identification of lymphatic vessels and CD31 for the identification of blood vessels was conducted. Tumors in vehicle-treated mice displayed a peri-tumoral area densely populated by lymphatic vessels. In contrast, tumors derived from BL-011256 treated mice were devoid of peri-tumoral lymphatic vessels. Notably, both vehicle-treated and BL-011256-treated animals displayed similar staining for peritumoral blood vessels, suggesting no effect on blood vessels (this is consistent with no activity on VEGFR2). Furthermore, PK sampling during the last day of dosing in a 14-day dosing schedule demonstrated that there is no compound accumulation during the repeat dosing schedule utilised in the B16F10 tumour efficacy experiment. In conclusion BL-011256 has been identified as a selective inhibitor of VEGFR3 that supresses both primary tumor growth and lymph node metastasis. Citation Format: Annabell Leske, Richard Foitzik, Donna Beaumont, John Bentley, Ylva Bergman, Chloe Brown, Michelle Camerino, Susan Charman, Neil Choi, Melanie De Silva, Matthew Chung, Hendrik Falk, Danny Ganame, Alison Gregg, Julian Grusovin, Andrew Harvey, Catherine Hemley, Ian Holmes, Belinda Huff, Daniel Inglis, Wilhelmus Kersten, Tina Lavranos, Romina Lessene, Gillian Lunniss, Brendon Monahan, Benjamin Morrow, Marica Nikac, George Nikolakopoulos, Dharam Paul, Tom Peat, Justin Ripper, Michaela Scherer, Paul Stupple, Karen White, Ian Street, Gabriel Kremmidiotis. BL-011256 is a novel VEGFR3 selective inhibitor, which suppresses tumor lymphatics and lymph node metastasis in an animal model of melanoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4029. doi:10.1158/1538-7445.AM2014-4029