PURPOSE:We previously demonstrated that overexpression of interleukin 8 (IL-8) in human transitional cell carcinoma (TCC) resulted in increased tumorigenicity and metastasis. This increase in tumor growth and metastasis can be attributed to the up-regulation in the expression and activity of the metalloproteinases MMP-2 and MMP-9.EXPERIMENTAL DESIGN:To investigate whether targeting IL-8 with a fully human anti-IL-8 antibody (ABX-IL8) could be a potential therapeutic strategy for controlling TCC growth, we studied its effects on TCC growth in vitro and in an in vivo mouse model. Human TCC cell lines 253J B-V and UM UC3 (high IL-8 producers), 253J (low IL-8), and 253J transfected with the IL-8 gene (high producer) were used.RESULTS:ABX-IL8 had no effect on TCC cell proliferation in vitro. However, in the orthotopic nude mouse model, after 4 weeks of treatment (100 micro g/week, i.p.), a significant decrease in tumor growth of both cell lines was observed. IL-8 blockade by ABX-IL8 significantly inhibited the expression, activity, and transcription of MMP-2 and MMP-9, resulting in decreased invasion through reconstituted basement membrane in vitro. The down-regulation of MMP-2 and MMP-9 in these cells could be explained by the modulation of nuclear factor-kappaB expression and transcriptional activity by ABX-IL8.CONCLUSIONS:Our data point to the potential use of ABX-IL8 as a modality to treat bladder cancer and other solid tumors, either alone or in combination with conventional chemotherapy or other antitumor agents.

Interleukin-8 (IL-8) has recently been shown to contribute to human melanoma progression by functioning as a mitogenic and angiogenic factor. In the present study, we investigated whether targeting IL-8 by a fully human anti-IL-8 antibody (ABX-IL8) could be a potential therapeutic strategy to control angiogenesis, growth, and metastasis of melanoma. The human melanoma cells A375SM (high IL-8 producer) and TXM-13 (intermediate IL-8 producer) were injected subcutaneously into nude mice, which were then treated with ABX-IL8 (I mg/3 times weekly, i.p., for 3 weeks). Tumor growth of both melanomas in ABX-IL8-treated mice was significantly inhibited when compared with control IgG-treated animals. ABX-IL8 treatment also suppressed experimental metastasis when the melanoma cells were injected intravenously. IL-8 blockade by ABX-IL8 significantly inhibited the promoter activity and the collagenase activity of matrix metalloproteinase-2 in human melanoma cells, resulting in decreased invasion through reconstituted basement membrane in vitro. In vivo, ABX-IL8 treatment resulted in decreased expression of matrix metalloproteinase-2, and decreased vascularization (angiogenesis) of tumors concomitant with increased apoptosis of tumor cells. Moreover, in an in vitro vessel formation assay, ABX-IL8 directly interfered with the tubule formation by human umbilical vein endothelial cells. Taken together, these results point to the potential utility of ABX-IL8 as a modality to treat melanoma and other solid tumors either alone or in combination with conventional chemotherapy or other anti-tumor agents.