As the largest family of ubiquitin-protein E3 ligases, the SCF (Skp1/Cullin/Rbx1/F-box protein) complexes ubiquitinate a broad range of proteins involved in cell cycle progression, signal transduction and transcription. Cullin1 (Cul1) serves as a rigid scaffold in SCF complex for Rbx1, Skp1 and F-box protein subunits assembly and aberrant expression of Cul1 is involved in dysfunction of SCF E3 ligases. To investigate the role of Cul1 in the development of melanoma, we examined the expression of Cul1 in melanocytic lesions at different stages and analyzed the correlation between Cul1 expression and clinicopathologic parameters by tissue microarray and immunohistochemistry. The result showed that Cul1 expression was significant increased in primary and metastatic melanoma compared with dysplastic nevi, while there was no significant difference of Cul1 expression between primary and metastatic melanoma, which suggested that Cul1 plays an important role in the initiation stage of melanoma development. We found knockdown of Cul1 inhibited melanoma cell growth and overexpression of Cul1 promoted melanoma cell growth through regulating CDK inhibitor p27Kip expression. Knockdown of Cul1 abrogated Skp2-induced p27 degradation in melanoma cells. These results suggested that Cul1 is involved in cell cycle regulation of melanoma cells via Cul1-dependent ubiquitination and degradation of the p27kip1 by SCFSkp2 complex. In conclusion, our data indicate that Cul1 may serve as a potential marker for human melanoma initiation and early diagnosis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1075.