Design, synthesis, and biological evaluation of water-soluble amino acid prodrug conjugates derived from combretastatin, dihydronaphthalene, and benzosuberene-based parent vascular disrupting agents

Laxman Devkota, Chen Ming Lin, Tracy E. Strecker, Yifan Wang, Justin K. Tidmore, Zhi Chen, Rajsekhar Guddneppanavar, Christopher J. Jelinek, Ramona Lopez, Li Liu, Ernest Hamel, Ralph P. Mason, David J. Chaplin, Mary Lynn Trawick, Kevin G. Pinney

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Targeting tumor vasculature represents an intriguing therapeutic strategy in the treatment of cancer. In an effort to discover new vascular disrupting agents with improved water solubility and potentially greater bioavailability, various amino acid prodrug conjugates (AAPCs) of potent amino combretastatin, amino dihydronaphthalene, and amino benzosuberene analogs were synthesized along with their corresponding water-soluble hydrochloride salts. These compounds were evaluated for their ability to inhibit tubulin polymerization and for their cytotoxicity against selected human cancer cell lines. The amino-based parent anticancer agents 7, 8, 32 (also referred to as KGP05) and 33 (also referred to as KGP156) demonstrated potent cytotoxicity (GI50 = 0.11-40 nM) across all evaluated cell lines, and they were strong inhibitors of tubulin polymerization (IC50 = 0.62-1.5 μM). The various prodrug conjugates and their corresponding salts were investigated for cleavage by the enzyme leucine aminopeptidase (LAP). Four of the glycine water-soluble AAPCs (16, 18, 44 and 45) showed quantitative cleavage by LAP, resulting in the release of the highly cytotoxic parent drug, whereas partial cleavage (<10-90%) was observed for other prodrugs (15, 17, 24, 38 and 39). Eight of the nineteen AAPCs (13-16, 42-45) showed significant cytotoxicity against selected human cancer cell lines. The previously reported CA1-diamine analog and its corresponding hydrochloride salt (8 and 10, respectively) caused extensive disruption (at a concentration of 1.0 μM) of human umbilical vein endothelial cells growing in a two-dimensional tubular network on matrigel. In addition, compound 10 exhibited pronounced reduction in bioluminescence (greater than 95% compared to saline control) in a tumor bearing (MDA-MB-231-luc) SCID mouse model 2 h post treatment (80 mg/kg), with similar results observed upon treatment (15 mg/kg) with the glycine amino-dihydronaphthalene AAPC (compound 44). Collectively, these results support the further pre-clinical development of the most active members of this structurally diverse collection of water-soluble prodrugs as promising anticancer agents functioning through a mechanism involving vascular disruption.

Original languageEnglish (US)
Pages (from-to)938-956
Number of pages19
JournalBioorganic and Medicinal Chemistry
Volume24
Issue number5
DOIs
StatePublished - Mar 1 2016

Keywords

  • Amino acid prodrug salts
  • Anti-cancer agents
  • Benzosuberene analogs
  • Combretastatin analogs
  • Dihydronaphthalene analogs
  • Inhibitors of tubulin polymerization
  • Small-molecule synthesis
  • Vascular disrupting agents

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmaceutical Science
  • Drug Discovery
  • Clinical Biochemistry
  • Organic Chemistry

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