This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wong, T. W. Articles by Vite, G. D. Search for Related Content PubMed PubMed Citation Articles by Wong, T. W. Articles by Vite, G. D.

Preclinical Antitumor Activity of BMS-599626, a pan-HER Kinase Inhibitor That Inhibits HER1/HER2 Homodimer and Heterodimer Signaling

Authors' Affiliations: ¹ Oncology Drug Discovery, ² Discovery MAP, and ³ Discovery Chemistry, Bristol Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey

Requests for reprints: Tai W. Wong, Bristol-Myers Squibb Pharmaceutical Research Institute, P.O. Box 4000, Princeton, NJ 08534. Phone: 609-252-4187; Fax: 609-252-6171; E-mail: tai.wong{at}bms.com.

Purpose: The studies described here are intended to characterize the ability of BMS-599626, a small-molecule inhibitor of the human epidermal growth factor receptor (HER) kinase family, to modulate signaling and growth of tumor cells that depend on HER1 and/or HER2.

Experimental Design: The potency and selectivity of BMS-599626 were assessed in biochemical assays using recombinant protein kinases, as well as in cell proliferation assays using tumor cell lines with varying degrees of dependence on HER1 or HER2 signaling. Modulation of receptor signaling was determined in cell assays by Western blot analyses of receptor autophosphorylation and downstream signaling. The ability of BMS-599626 to inhibit receptor heterodimer signaling in tumor cells was studied by receptor coimmunoprecipitation. Antitumor activity of BMS-599626 was evaluated using a number of different xenograft models that represent a spectrum of human tumors with HER1 or HER2 overexpression.

Results: BMS-599626 inhibited HER1 and HER2 with IC₅₀ of 20 and 30 nmol/L, respectively, and was highly selective when tested against a broad panel of diverse protein kinases. Biochemical studies suggested that BMS-599626 inhibited HER1 and HER2 through distinct mechanisms. BMS-599626 abrogated HER1 and HER2 signaling and inhibited the proliferation of tumor cell lines that are dependent on these receptors, with IC₅₀ in the range of 0.24 to 1 µmol/L. BMS-599626 was highly selective for tumor cells that depend on HER1/HER2 and had no effect on the proliferation of cell lines that do not express these receptors. In tumor cells that are capable of forming HER1/HER2 heterodimers, BMS-599626 inhibited heterodimerization and downstream signaling. BMS-599626 had antitumor activity in models that overexpress HER1 (GEO), as well as in models that have HER2 gene amplification (KPL4) or overexpression (Sal2), and there was good correlation between the inhibition of receptor signaling and antitumor activity.

Conclusions: BMS-599626 is a highly selective and potent inhibitor of HER1 and HER2 kinases and inhibits tumor cell proliferation through modulation of receptor signaling. BMS-599626 inhibits HER1/HER2 receptor heterodimerization and provides an additional mechanism of inhibiting tumors in which receptor coexpression and heterodimerization play a major role in driving tumor growth. The preclinical data support the advancement of BMS-599626 into clinical development for the treatment of cancer.

This article has been cited by other articles:

				S. V. Sharma and J. Settleman Oncogene addiction: setting the stage for molecularly targeted cancer therapy Genes & Dev., December 15, 2007; 21(24): 3214 - 3231. [Abstract] [Full Text] [PDF]