title: Broad-spectrum G protein-coupled receptor antagonist, [D-Arg1,D-Trp5,7,9,Leu11]SP: a dual inhibitor of growth and angiogenesis in pancreatic cancer.
abstract: Substance P analogues, including [D-Arg(1),D-Trp(5,7,9),Leu(11)]SP (SPA) are broad-spectrum G protein-coupled receptor (GPCR) antagonists that have potential antitumorigenic activities, although the mechanism(s) are not completely understood. Here, we examined the effects of SPA in ductal pancreatic cancers that express multiple GPCRs for mitogenic agonists and also produce proangiogenic chemokines. Using HPAF-II, a well-differentiated pancreatic cancer cell line as our model system, we showed that SPA inhibited multiple neuropeptide-induced Ca(2+) mobilization, DNA synthesis, and anchorage-independent growth in vitro. SPA also significantly attenuated the growth of HPAF-II tumor xenografts in nude mice beyond the treatment period. Interestingly, SPA markedly increased apoptosis but moderately decreased proliferation marker, Ki-67 in the tumor xenografts implying additional mechanism(s) for the significant growth inhibitory effect observed in vivo. HPAF-II cells express ELR(+) CXC chemokines, including IL-8/CXCL8, which bind to CXCR2 (a member of GPCR superfamily) and promote angiogenesis in multiple cancers, including pancreatic cancer. SPA inhibited CXCR2-mediated Ca(2+) mobilization and blocked specifically IL-8/CXCL8-induced angiogenesis in rat corneal micropocket assay in vivo. A salient feature of the results presented here is that SPA markedly reduced tumor-associated angiogenesis in the HPAF-II xenografts in vivo. Our results show that SPA, a broad-spectrum GPCR antagonist attenuates tumor growth in pancreatic cancer via a dual mechanism involving both the antiproliferative and antiangiogenic properties. We conclude that this novel dual-inhibitory property of SPA could be of significant therapeutic value in pancreatic cancer, when used in combination with other antiproliferative and/or antiangiogenic agents.
authors.affiliation: Department of Medicine, Division of Digestive Diseases, and Molecular Biology Institute, David Geffen School of Medicine, University of California at Los Angeles, 90095-1786, USA.
authors.forename: Sushovan
authors.initials: S
authors.lastname: Guha
authors.forename: Guido
authors.initials: G
authors.lastname: Eibl
authors.forename: Krisztina
authors.initials: K
authors.lastname: Kisfalvi
authors.forename: Robert S
authors.initials: RS
authors.lastname: Fan
authors.forename: Marie
authors.initials: M
authors.lastname: Burdick
authors.forename: Howard
authors.initials: H
authors.lastname: Reber
authors.forename: Oscar J
authors.initials: OJ
authors.lastname: Hines
authors.forename: Robert
authors.initials: R
authors.lastname: Strieter
authors.forename: Enrique
authors.initials: E
authors.lastname: Rozengurt
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D021441:Carcinoma, Pancreatic Ductal / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D048708:Cell Growth Processes / Q000187:drug effects; D003315:Cornea / Q000098:blood supply; D004273:DNA, Neoplasm / Q000096:biosynthesis; D006801:Humans; D016209:Interleukin-8 / Q000037:antagonists & inhibitors; D019394:Ki-67 Antigen / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000473:pathology; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D051381:Rats; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors*; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: D004273:DNA, Neoplasm; D016209:Interleukin-8; D019394:Ki-67 Antigen; D043562:Receptors, G-Protein-Coupled; C102471:substance P, Arg(1)-Trp(5,7,9)-Leu(11)-; D013373:Substance P