title: Water-soluble HPMA copolymer-wortmannin conjugate retains phosphoinositide 3-kinase inhibitory activity in vitro and in vivo.
abstract: Phosphoinositide kinases and ATM-related genes play a central role in many physiological processes. Activation of phosphoinositide 3-kinase (PI 3-kinase) is essential for signal transduction by many growth factors and oncogenes and may contribute to tumor progression. In the nanomolar range, Wortmannin (WM), a fungal metabolite, is a potent inhibitor of type I PI 3-kinase; it covalently modifies its catalytic subunit. Because WM is soluble only in organic solvents and unstable in water, there are difficulties in its use in vivo. To generate a water-soluble WM derivative, we used a conjugate of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer and 11-O-desacetylwortmannin (DAWM), which has a slightly lower inhibitory activity than WM. We covalently attached DAWM to HPMA copolymer containing oligopeptide (GFLG) side-chains. The final product had an estimated molecular mass of 20 kDa and contained 2 wt.% of DAWM. The HPMA copolymer (PHPMA)-DAWM conjugate inhibited type I PI 3-kinase activity in vitro and growth factor-stimulated activation of Akt in vivo; it possessed approximately 50% of the inhibitory activity of DMSO solubilized WM. The specificity and stability of the PHPMA-DAWM conjugate is currently under investigation. The new water-soluble form of WM may be useful in investigations of the role of PI 3-kinase in tumor progression and other cellular biological functions in vivo.
authors.affiliation: Department of Medicine, St. Elizabeth's Medical Center, TUSM, Boston, MA 02135, USA. lvartico@pol.net
authors.forename: L
authors.initials: L
authors.lastname: Varticovski
authors.forename: Z R
authors.initials: ZR
authors.lastname: Lu
authors.forename: K
authors.initials: K
authors.lastname: Mitchell
authors.forename: I
authors.initials: I
authors.lastname: de Aos
authors.forename: J
authors.initials: J
authors.lastname: Kopecek
mesh_terms: D000730:Androstadienes / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004337:Drug Carriers / Q000737:chemistry; D004705:Endocytosis; D020536:Enzyme Activators / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D006133:Growth Substances / Q000494:pharmacology; D008689:Methacrylates / Q000737:chemistry; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D012995:Solubility; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D004337:Drug Carriers; D020536:Enzyme Activators; D006133:Growth Substances; D008689:Methacrylates; D019869:Phosphatidylinositol 3-Kinases; C032802:hydroxypropyl methacrylate; D000077191:Wortmannin