Andrew John Harvey

Design and synthesis of type-III mimetics of ShK toxin

ShK toxin is a structurally defined, 35-residue polypeptide which blocks the voltage-gated Kv1.3 potassium channel in T-lymphocytes and has been identified as a possible immunosuppressant. Our interest lies in the rational design and synthesis of type-III mimetics of protein and polypeptide structure and function. ShK toxin is a challenging target for mimetic design as its binding epitope consists of relatively weakly binding residues, some of which are discontinuous. We discuss here our investigations into the design and synthesis of 1st generation, small molecule mimetics of ShK toxin and highlight any principles relevant to the generic design of type-III mimetics of continuous and discontinuous binding epitopes. We complement our approach with attempted pharmacophore-based database mining.

Synthesis and Biological Evaluation of Chalcones as Inhibitors of the Voltage-Gated Potassium Channel Kv1.3

Chalcone derivatives of the natural product khellinone were synthesised and screened for bioactivity against the voltage-gated potassium channel Kv1.3. X-ray crystallography was employed to investigate relationships between the structure and function of a selection of the reported chalcones.

Abstract 4115: BNC420 is a novel VEGFR3 selective inhibitor, which unlike the pan-VEGFR inhibitor Sunitinib, suppresses lymphatic metastasis in a model of metastatic melanoma

The dissemination of cancer cells through the lymphatic system is a well-known route of metastasis. Studies have implicated the hypoxic tumor microenvironment as an instigator of tumor cell invasion and metastatic spread. The use of angiogenesis inhibitors targeting VEGFR2 has been reported in preclinical models to augment metastasis through increased hypoxia within the tumor microenvironment. We have sought to identify a selective VEGFR3 targeting compound that will inhibit metastatic spread through lymphatic dissemination without the concomitant hypoxia induced metastasis effect associated with VEGFR2 targeting. BNC420 is a novel small molecule inhibitor of VEGFR3 phosphorylation that displays significant selectivity over VEGFR2. In phosphorylation detection ELISA based assays BNC420 exhibited a 25 fold greater potency for VEGFR3 over VEGFR2 with IC50 of 30nM and 744nM respectively. We investigated the activity of BNC420 and the pan-VEGFR inhibitor Sunitinib in the B16F10 murine melanoma model. This model involves the intradermal administration of B16F10 melanoma cells in the mouse ear resulting in the formation of a primary lesion, metastatic satellite lesions (in-transit) and regional lymph node metastasis. While Sunitinib slowed the growth of the primary lesion, as expected, it did not inhibit the development of lymph node metastasis and appeared to enhance the development of in-transit satellite lesions by 38% compared to its corresponding vehicle control. In contrast, only 20% of animals treated with BNC420 exhibited in-transit lesions compared to 53% in the corresponding vehicle control. Furthermore, a 50% reduction in the number of metastasis to the draining lymph nodes was seen in BNC420 treated animals. The lymph node metastatic lesions were significantly smaller compared to control and in some instances only detected under microscopic examination. Melanoma lesions in animals treated with BNC420 were devoid of peritumoral lymphatic vessels. These results demonstrate that selective inhibition of VEGFR3 utilising the novel small molecule BNC420 effectively inhibits the development of both in-transit metastatic lesions and lymph node metastasis while being unencumbered by the pro-metastatic effects that can accompany VEGFR2 inhibition through the induction of tumor hypoxia. Citation Format: Annabell Leske, Tina Lavranos, Donna Beaumont, Chloe Brown, Darham Paul, Daniel Inglis, Michaela Scherer, Andrew Harvey, Gabriel Kremmidiotis. BNC420 is a novel VEGFR3 selective inhibitor, which unlike the pan-VEGFR inhibitor Sunitinib, suppresses lymphatic metastasis in a model of metastatic melanoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4115. doi:10.1158/1538-7445.AM2015-4115

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