Novel proteasome inhibitor PS-341 inhibits activation of nuclear factor-kappa B, cell survival, tumor growth, and angiogenesis in squamous cell carcinoma CLINICAL CANCER RESEARCH Sunwoo, J. B., Chen, Z., Dong, G., Yeh, N., Bancroft, C. G., Sausville, E., Adams, J., Elliott, P., Van Waes, C. 2001; 7 (5): 1419-1428


We have shown that activation of nuclear factor-kappa B (NF-kappa B) promotes cell survival and expression of cytokines such as growth-regulated oncogene-alpha, which can modulate angiogenesis, growth, and metastasis of squamous cell carcinoma (SCC). Activation of NF-kappa B and cytoprotective genes in cancer may result from signal-induced phosphorylation and proteasome-dependent degradation of inhibitor-kappa B. In this study, we examined the effects of the novel proteasome inhibitor PS-341 on activation of NF-kappa B and cell survival, growth, and angiogenesis in murine and human SCC cell lines. PS-341 inhibited activation of NF-kappa B DNA binding and functional reporter activity at concentrations between 10(-8) and 10(-7) M. Cytotoxicity was observed at 10(-7) M in four murine and two human SCC lines, and followed early cleavage of poly(ADP-ribose) polymerase, a marker of caspase-mediated apoptosis. In vivo, PS-341 inhibited growth of murine and human SCC in mice at doses of 1--2 mg/kg given three times weekly, and dose-limiting toxicity was encountered at 2 mg/kg. Tumor growth inhibition was associated with a marked decrease in vessel density. PS-341 inhibited expression of the proangiogenic cytokines growth-regulated oncogene-alpha and vascular endothelial growth factor by SCC in the range at which PS-341 inhibits NF-kappa B. We conclude that PS-341 inhibits activation of NF-kappa B pathway components related to cell survival, tumor growth, and angiogenesis in SCC.

View details for Web of Science ID 000168768500044

View details for PubMedID 11350913