title: Antiangiogenic and antitumor activity of LP-261, a novel oral tubulin binding agent, alone and in combination with bevacizumab.
abstract: LP-261 is a novel tubulin targeting anticancer agent that binds at the colchicine site on tubulin, inducing G2/M arrest. Screening in the NCI60 cancer cell lines resulted in a mean GI50 of approximately 100 nM. Here, we report the results of testing in multiple mouse xenograft models and angiogenesis assays, along with bioavailability studies. To determine the antiangiogenic activity of LP-261, both in vitro and ex vivo experiments were performed. Human umbilical vein endothelial cells (HUVECs) were incubated with LP-261 at 50 nM to 10 μM. LP-261 was also tested in a rat aortic ring assay, from 20 nM to 10 μM. Multiple mouse xenograft studies were performed to assess in vivo antitumor activity. LP-261 was tested as a single agent in colon adenocarcinoma (SW620) and prostate cancer (LNCaP and PC3) xenografts, evaluating several different dosing schedules. LP-261 was also used in combination with bevacizumab in the SW620 xenograft model. LP-261 also exhibited high oral bioavailability and apparent lack of efflux by intestinal transporters such as ABCB1. LP-261 is a very potent inhibitor of angiogenesis, preventing microvessel outgrowth in the rat aortic ring assay and HUVEC cell proliferation at nanomolar concentrations. Complete inhibition of tumor growth was achieved in the PC3 xenograft model and shown to be schedule dependent. Excellent inhibition of tumor growth in the SW620 model was observed, comparable with paclitaxel. Combining oral, low dose LP-261 with bevacizumab led to significantly improved tumor inhibition. Oral LP-261 is very effective at inhibiting tumor growth in multiple mouse xenograft models and is well tolerated.
authors.affiliation: Clinical Pharmacology Program, SAIC-Frederick, NCI-Frederick, Frederick, MD 21702, USA.
authors.forename: Erin R
authors.initials: ER
authors.lastname: Gardner
authors.forename: Martha
authors.initials: M
authors.lastname: Kelly
authors.forename: Eric
authors.initials: E
authors.lastname: Springman
authors.forename: Kyoung-jin
authors.initials: KJ
authors.lastname: Lee
authors.forename: Haiqing
authors.initials: H
authors.lastname: Li
authors.forename: William
authors.initials: W
authors.lastname: Moore
authors.forename: William D
authors.initials: WD
authors.lastname: Figg
mesh_terms: D000284:Administration, Oral; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage; D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D000068258:Bevacizumab; D001682:Biological Availability; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects; D006801:Humans; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D007539:Isonicotinic Acids / Q000008:administration & dosage; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009369:Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D018919:Neovascularization, Physiologic / Q000187:drug effects; D017239:Paclitaxel / Q000008:administration & dosage; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D013449:Sulfonamides / Q000008:administration & dosage; D013997:Time Factors; D050257:Tubulin Modulators / Q000008:administration & dosage; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D007539:Isonicotinic Acids; C562240:N-(3-(1H-indol-4-yl)-5-(2-methoxyisonicotinoyl)phenyl)methanesulfonamide; D013449:Sulfonamides; D050257:Tubulin Modulators; D000068258:Bevacizumab; D017239:Paclitaxel
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