title: Tumor attenuation by combined heparan sulfate and polyamine depletion.
abstract: Cells depend on polyamines for growth and their depletion represents a strategy for the treatment of cancer. Polyamines assemble de novo through a pathway sensitive to the inhibitor, alpha-difluoromethylornithine (DFMO). However, the presence of cell-surface heparan sulfate proteoglycans may provide a salvage pathway for uptake of circulating polyamines, thereby sparing cells from the cytostatic effect of DFMO. Here we show that genetic or pharmacologic manipulation of proteoglycan synthesis in the presence of DFMO inhibits cell proliferation in vitro and in vivo. In cell culture, mutant cells lacking heparan sulfate were more sensitive to the growth inhibitory effects of DFMO than wild-type cells or mutant cells transfected with the cDNA for the missing biosynthetic enzyme. Moreover, extracellular polyamines did not restore growth of mutant cells, but completely reversed the inhibitory effect of DFMO in wild-type cells. In a mouse model of experimental metastasis, DFMO provided in the water supply also dramatically diminished seeding and growth of tumor foci in the lungs by heparan sulfate-deficient mutant cells compared with the controls. Wild-type cells also formed tumors less efficiently in mice fed both DFMO and a xylose-based inhibitor of heparan sulfate proteoglycan assembly. The effect seemed to be specific for heparan sulfate, because a different xyloside known to affect only chondroitin sulfate did not inhibit tumor growth. Hence, combined inhibition of heparan sulfate assembly and polyamine synthesis may represent an additional strategy for cancer therapy.
authors.affiliation: Department of Cell and Molecular Biology, Biomedical Center C13, Lund University, P.O.B. 94, S-221 84 Lund, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Belting
authors.forename: Lubor
authors.initials: L
authors.lastname: Borsig
authors.forename: Mark M
authors.initials: MM
authors.lastname: Fuster
authors.forename: Jillian R
authors.initials: JR
authors.lastname: Brown
authors.forename: Lo
authors.initials: L
authors.lastname: Persson
authors.forename: Lars-Ake
authors.initials: LA
authors.lastname: Fransson
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Esko
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D016466:CHO Cells; D006224:Cricetinae; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000518:Eflornithine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D014453:Glucuronosyltransferase / Q000096:biosynthesis; D006497:Heparan Sulfate / Q000494:pharmacology*; D051379:Mice; D016513:Mice, SCID; D008954:Models, Biological; D008957:Models, Genetic; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D011073:Polyamines / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism; D013096:Spermine / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D018076:DNA, Complementary; D000518:Eflornithine; D004791:Enzyme Inhibitors; D014453:Glucuronosyltransferase; D006497:Heparan Sulfate; D011073:Polyamines; D011509:Proteoglycans; D013096:Spermine; C111364:galactosylgalactoylxylosylprotein 3-beta-glucuronosyltransferase