title: Vasoactive intestinal peptide-camptothecin conjugates inhibit the proliferation of breast cancer cells.
abstract: The effects of vasoactive intestinal peptide-camptothecin (VIP-CPT) conjugates were investigated on breast cancer cells and cells transfected with VIP receptors (R). (Ala(2,8,9,19,24.25.27), Nle(17), Lys(28))VIP, (A-NL-K)VIP, was synthesized and Lys(28) was coupled to a linker, N-methyl-amino-ethyl-glycine, L2, which formed a carbamate bond with CPT. The resulting (A-NL-K)VIP-L2-CPT was cytotoxic for MCF7 breast cancer cells, which have VPAC(1)-R, with IC(50) values of 380 and 90 nM using the MTT and clonogenic assays, respectively. (A-NL-K)VIP, (A-NL-K)VIP-L2 and (A-NL-K)VIP-L2-CPT inhibited specific binding of (125)I-VIP to 3T3 cells transfected with VPAC(1)-R with IC(50) values of 1.9, 56 and 126 nM, respectively. In contrast, (A-NL-K)VIP, (A-NL-K)VIP-L2 and (A-NL-K)VIP-L2-CPT inhibited specific binding of (125)I-Ro25-1553 to 3T3 cells transfected with VPAC(2)-R with IC(50) values of 3.9, 3162 and 2690 nM, respectively. (A-NL-K)VIP, (A-NL-K)VIP-L2 and (A-NL-K)VIP-L2-CPT caused increased cAMP after addition to MCF7 cells. (125)I-(A-NL-K)VIP-L2-CPT was internalized by MCF7 cells at 37 degrees C but not 4 degrees C. These results indicate that (A-NL-K)VIP-L2-CPT is a VPAC(1)-R agonist which is cytotoxic for breast cancer cells.
authors.affiliation: Department of Health and Human Services, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, United States. moodyt@mail.nih.gov
authors.forename: Terry W
authors.initials: TW
authors.lastname: Moody
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Mantey
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Fuselier
authors.forename: David H
authors.initials: DH
authors.lastname: Coy
authors.forename: Robert T
authors.initials: RT
authors.lastname: Jensen
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D002166:Camptothecin / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D051379:Mice; D014660:Vasoactive Intestinal Peptide / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D002166:Camptothecin