Role of PLK1 in epithelial-mesenchymal transition in human melanoma

Polo-like kinase 1 (PLK1), a serine/threonine kinase and important cell cycle regulator, is overexpressed in melanoma and its expression has been associated with poor disease prognosis. PLK1 has been shown to interact with NUMB, a NOTCH antagonist. However, the exact role of PLK1-NUMB-NOTCH axis in epithelial-mesenchymal transition (EMT) and melanoma progression is unclear. In this study, Affymetrix microarray analysis was performed to determine differentially expressed genes following doxycyclin induced shRNA-mediated knockdown of PLK1 in human melanoma cells that showed significant modulations in EMT and metastasis related genes. Total RNA (biological triplicates) was isolated using an RNeasy Plus Mini Kit (QIAGEN, CA) from experimental groups. The RNA samples were hybridized to the Affymetrix Human Transcriptome Array (HTA) 2.0 microarrays and processed by the UW-Madison Gene Expression Center in the UW Biotechnology Center for Affymetrix GeneChip Services.