title: Effect of a nitric oxide synthase inhibitor and a CXC chemokine receptor-4 antagonist on tumor growth and metastasis in a xenotransplanted mouse model of adenoid cystic carcinoma of the oral floor.
abstract: Nitric oxide (NO) is related to angiogenesis and tumor progression and chemokine receptor-4 (CXCR4) plays a central role in cell migration in metastasis and dissemination of cancer. The present study evaluated the effectiveness of a NOS inhibitor and a CXCR4 antagonist, given as single agents or in combination, in a xenotransplanted mouse model of adenoid cystic carcinoma (ACC) of the oral floor. A metastatic tumor (ACCIM) derived from a cervical metastatic lesion of human ACC that was transplantable in nude mice was used. ACCIM showed a high frequency of spontaneous metastasis to the lung when transplanted subcutaneously in nude mice. Mice with subcutaneous transplants of ACCIM were subdivided into six groups and intraperitoneally received one of the following treatments daily for 5 weeks: a) PBS (control), b) AMD3100 (CXCR4 antagonist), c) L-NAME (NOS inhibitor), d) 1400W (iNOS inhibitor), e) both AMD3100 and L-NAME (AMD3100+L-NAME) and f) both AMD3100 and 1400W (AMD3100+1400W). Tumor growth was evaluated during treatment and metastasis was assessed at 28 weeks. Single-agent treatment with AMD3100, L-NAME or 1400W inhibited tumor growth by 20.8, 26.5 and 54.5%, respectively. Combined treatment with AMD3100+L-NAME and AMD3100+1400W inhibited tumor growth remarkably by 48.0 and 50.2%, respectively. Immunohistochemical analysis revealed lower expression of CXCR4, iNOS and eNOS in tumor cells treated with AMD3100+L-NAME or AMD3100+1400W compared to control tumor cells and increased numbers of apoptotic tumor cells were demonstrated using the TUNEL method. CXCR4 expression decreased in 1400W-treated tumors using western blot analysis. When the effect of each agent on tumor-induced angiogenesis in tumor stroma was examined histologically, microvessel density was significantly lower in the groups treated with 1400W, AMD3100+L-NAME or AMD3100+1400W compared to the control, AMD3100 and L-NAME groups. Moreover, treatment with AMD3100 or 1400W markedly inhibited lung metastasis. Our results indicated that single-agent treatment with 1400W and combined treatment with AMD3100+L-NAME or AMD3100+1400W induced apoptosis and significantly inhibited tumor-induced angiogenesis and proliferation of ACCIM in vivo. Blockade of CXCR4 and iNOS was suggested to inhibit lung metastases from ACCIM. CXCR4 and iNOS may, thus, be important prognostic factors for long-term survival in ACC.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Takaoka
authors.forename: Sayaka
authors.initials: S
authors.lastname: Hidaka
authors.forename: Susumu
authors.initials: S
authors.lastname: Hashitani
authors.forename: Emi
authors.initials: E
authors.lastname: Segawa
authors.forename: Michiyo
authors.initials: M
authors.lastname: Yamamura
authors.forename: Noriaki
authors.initials: N
authors.lastname: Tanaka
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Zushi
authors.forename: Kazuma
authors.initials: K
authors.lastname: Noguchi
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kishimoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Urade
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D003528:Carcinoma, Adenoid Cystic / Q000235:genetics* / Q000473:pathology; D002465:Cell Movement / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology / Q000556:secondary; D051379:Mice; D009062:Mouth Neoplasms / Q000235:genetics* / Q000473:pathology; D009362:Neoplasm Metastasis / Q000235:genetics / Q000473:pathology; D009389:Neovascularization, Pathologic; D009569:Nitric Oxide / Q000235:genetics / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D019718:Receptors, CXCR4 / Q000096:biosynthesis / Q000235:genetics*; D014183:Transplantation, Heterologous
chemical_list: C514936:CXCR4 protein, mouse; D004791:Enzyme Inhibitors; D019718:Receptors, CXCR4; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase