This Article Full Text Full Text (PDF) Supplementary Data Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend 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 Google Scholar Articles by Villares, G. J. Articles by Bar-Eli, M. PubMed PubMed Citation Articles by Villares, G. J. Articles by Bar-Eli, M.

Overexpression of Protease-Activated Receptor-1 Contributes to Melanoma Metastasis via Regulation of Connexin 43

Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas

Requests for reprints: Menashe Bar-Eli, Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Unit 173, 1515 Holcombe Boulevard, Houston, TX 77030. Phone: 713-794-4004; Fax: 713-792-8747; E-mail: mbareli{at}mdanderson.org.

Key Words: Thrombin Receptor • Connexin 43 • AP-1 • SP-1 • Melanoma • shRNA

Protease-activated receptor-1 (PAR-1) is a key player in melanoma metastasis with higher expression seen in metastatic melanoma cell lines and tissue specimens. cDNA microarray and Western blot analyses reveal that the gap junctional intracellular communication molecule connexin 43 (Cx-43), known to be involved in tumor cell diapedesis and attachment to endothelial cells, is significantly decreased after PAR-1 silencing in metastatic melanoma cell lines. Furthermore, Cx-43 promoter activity was significantly inhibited in PAR-1–silenced cells, suggesting that PAR-1 regulates Cx-43 at the transcriptional level. Chromatin immunoprecipitation studies showed a reduction in the binding of SP-1 and AP-1 transcription factors to the promoter of Cx-43. Both transcription factors have been shown previously to be required for maximal Cx-43 promoter activity. These results were corroborated by mutating the AP-1 and SP-1 binding sites resulting in decreased Cx-43 promoter activity in PAR-1–positive cells. Moreover, as Cx-43 has been shown to facilitate arrest of circulating tumor cells at the vascular endothelium, melanoma cell attachment to endothelial cells was significantly decreased in PAR-1–silenced cells, with this effect being abrogated after PAR-1 rescue. Herein, we report that up-regulation of PAR-1 expression, seen in melanoma progression, mediates high levels of Cx-43 expression. As both SP-1 and AP-1 transcription factors act as positive regulators of Cx-43, our data provide a novel mechanism for the regulation of Cx-43 expression by PAR-1. Indeed, Cx-43 expression was restored following PAR-1 rescue in PAR-1–silenced cells. Taken together, our data support the tumor promoting function of Cx-43 in melanoma. [Cancer Res 2009;69(16):6730–7]

This article has been cited by other articles:

				V. O. Melnikova, K. Balasubramanian, G. J. Villares, A. S. Dobroff, M. Zigler, H. Wang, F. Petersson, J. E. Price, A. Schroit, V. G. Prieto, et al. Crosstalk between Protease-activated Receptor 1 and Platelet-activating Factor Receptor Regulates Melanoma Cell Adhesion Molecule (MCAM/MUC18) Expression and Melanoma Metastasis J. Biol. Chem., October 16, 2009; 284(42): 28845 - 28855. [Abstract] [Full Text] [PDF]