In this study, we demonstrate that the CXC family of chemokines displays disparate angiogenic activity depending upon the presence or absence of the ELR motif. CXC chemokines containing the ELR motif (ELR-CXC chemokines) were found to be potent angiogenic factors, inducing both in vitro endothelial chemotaxis and in vivo corneal neovascularization. In contrast, the CXC chemokines lacking the ELR motif, platelet factor 4, interferon ␥-inducible protein 10, and monokine induced by ␥-interferon, not only failed to induce significant in vitro endothelial cell chemotaxis or in vivo corneal neovacularization but were found to be potent angiostatic factors in the presence of either ELR-CXC chemokines or the unrelated angiogenic factor, basic fibroblast growth factor. Additionally, mutant interleukin-8 proteins lacking the ELR motif demonstrated potent angiostatic effects in the presence of either ELR-CXC chemokines or basic fibroblast growth factor. In contrast, a mutant of monokine induced by ␥-interferon containing the ELR motif was found to induce in vivo angiogenic activity. These findings suggest a functional role of the ELR motif in determining the angiogenic or angiostatic potential of CXC chemokines, supporting the hypothesis that the net biological balance between angiogenic and angiostatic CXC chemokines may play an important role in regulating overall angiogenesis.Angiogenesis, characterized by the neoformation of blood vessels, is an essential biological event encountered in a number of physiological and pathological processes, such as embryonic development, the formation of inflammatory granulation tissue during wound healing, chronic inflammation, and the growth of malignant solid tumors (1-5). Neovascularization can be rapidly induced in response to diverse pathophysiologic stimuli. Under conditions of homeostasis, the rate of capillary endothelial cell turn-over is typically measured in months or years (6, 7). However, the process of angiogenesis during normal wound repair is rapid, transient, and tightly controlled. During neovascularization, normally quiescent endothelial cells are stimulated, degrade their basement membrane and proximal extracellular matrix, migrate directionally, divide, and organize into new functioning capillaries invested by a basal lamina (1-5). The abrupt termination of angiogenesis that accompanies the resolution of the wound repair suggests two possible mechanisms of control: a marked reduction in angiogenic mediators coupled with a simultaneous increase in the level of angiostatic factors that inhibit new vessel growth (8). In contrast to neovascularization of normal wound repair, tumorigenesis is associated with exaggerated angiogenesis, suggesting the existence of augmented angiogenic and reduced levels of angiostatic mediators (3, 9). Although most investigations studying angiogenesis have focused on the identification and mechanism of action of angiogenic factors, recent evidence suggests that angiostatic factors may play an equally important role in the control of neova...

The salient feature of solid tumor growth is the strict dependence on local angiogenesis. We have previously demonstrated that IL-8 is an angiogenic factor present in freshly isolated specimens of human non-small cell lung cancer (NSCLC). Using a model of human NSCLC tumorigenesis in SCID mice, we now report that IL-8 acts as a promoter of human NSCLC tumor growth through its angiogenic properties. Passive immunization with neutralizing antibodies to IL-8 resulted in more than 40% reduction in tumor size and was associated with a decline in tumor-associated vascular density and angiogenic activity. IL-8 did not act as an autocrine growth factor for NSCLC proliferation. The reduction in primary tumor size in response to neutralizing antibodies to IL-8 was also accompanied by a trend toward a decrease in spontaneous metastasis to the lung. These data support the notion that IL-8 plays a significant role in mediating angiogenic activity during tumorigenesis of human NSCLC, thereby offering a potential target for immunotherapy against solid tumors. ( J. Clin. Invest. 1996. 97:2792-2802.)

Medtronic. Dr. Nead has received personal fees from Medtronic. Dr. Bowling has received personal fees from Medtronic. Dr. Murgu has received personal fees from Medtronic, Boston Scientific, Pinnacle Biologics, Olympus, Cook, Auris Robotics, and Elsevier; and has stock ownership in Concordia, Boston Scientific, and Merck. Dr. Krimsky has received personal fees from Medtronic, Innovital Systems, Gala Therapeutic, SOC, and Peytant; has stock ownership with Innovital Systems and CSA Medical; and has patents pending with Medtronic and Merit. Dr. Murillo has received support from Medtronic. Dr. LeMense has received personal fees from Medtronic. Dr. Minnich has received personal fees from Medtronic. Dr. Bansal has received personal fees from Medtronic, Pinnacle Biologics, Sunovion, and Veran Medical. Dr. Ellis has received support from Medtronic. Dr. Mahajan has received personal fees from Medtronic. Dr. Gildea has received personal fees from Medtronic. Dr. Bechara has received support from Medtronic. Dr. Sztejman has received support from Medtronic. Dr. Flandes has received grants from BTG-PneumRx and Ambu; and personal fees from Medtronic, BTG-PneumRx, Olympus, Ambu, PulmonX, and Boston Scientific. Dr. Rickman has received personal fees from Medtronic, Veran Medical, BD, Olympus, and Abbvie. Dr. Benzaquen has received support from Medtronic. Dr. Hogarth has received personal fees from Medtronic, Auris Surgical Robotics, Boston Scientific, Grifols, Shire, and CSL; and has stock ownership with Auris Surgical Robotics. Dr. Linden has received support from Medtronic. Dr. Wahidi has received personal fees from Medtronic and Veran Medical. Dr. Mattingley has received personal fees from Medtronic and is current employee of Medtronic (employment began after completion of enrollment). Dr. Hood is an employee with stock ownership at Medtronic; and has stock ownership with Boston Scientific. Ms. Lin and Ms. Wolvers are employees with stock ownership at Medtronic. Dr. Khandar has received personal fees from Medtronic.

SummaryThe success of solid tumor growth and metastasis is dependent upon angiogenesis. Neovascularization within the tumor is regulated, in part, by a dual and opposing system of angiogenic and angiostatic factors. We now report that IP-10, a recently described angiostatic factor, is a potent angiostatic factor that regulates non-small cell lung cancer (NSCLC)-derived angiogenesis, tumor growth, and spontaneous metastasis. We initially found significantly elevated levels of IP-10 in freshly isolated human NSCLC samples of squamous cell carcinoma (SCCA). In contrast, levels of IP-10 were equivalent in either normal lung tissue or adenocarcinoma specimens. The neoplastic cells in specimens of SCCA were the predominant cells that appeared to express IP-10 by immunolocalization. Neutralization of IP-10 in SCCA tumor specimens resulted in enhanced tumor-derived angiogenic activity. Using a model of human NSCLC tumorigenesis in SCID mice, we found that NSCLC tumor growth was inversely correlated with levels of plasma or tumor-associated IP-10. IP-10 in vitro functioned as neither an autocrine growth factor nor as an inhibitor of proliferation of the NSCLC cell lines, tkeconstitution of intratumor IP-10 for a period of 8 wk resulted in a significant inhibition of tumor growth, tumor-associated angiogenic activity and neovascularization, and spontaneous lung metastases; whereas, neutralization of IP-10 for 10 wk augmented tumor growth. These findings support the notion that tumor-derived IP-10 is an important endogenous angiostatic factor in NSCLC.

No abstract