Microarray analysis reveals CC chemokine CCL-1 responsive gene expression in human HeLa cells

Human CC chemokine, CCL-1 is a chemotactic cytokine implicated in a variety of biological responses, namely inflammation and chemotaxis, in many cell types. We have previously shown that the CC chemokine, CCL-1 and its receptor CCR8 are expressed and causes migration of cancer cells: skin, melanoma, MDMA (breast cancer) and Kaposi's sarcoma spindle cells. In the present study we examined the role of CCL-1 and its receptor CCR8 in the regulation of gene expression by microarray analysis and targeted siRNA inhibition in human cervical carcinoma (HeLa) cells. We have found that HeLa cells constitutively express CCR8 and this expression of CCR8 is stimulated by CCL-1. Inorder to understand the underlying mechanisms we looked at gene expression during CCL1 and CCR8 mediated interactions. Affymetrix human microarray data analysis revealed that CCL-1 regulates genes that are involved in angiogenesis, apoptosis, oxidative stress and chemotaxis. CC chemokine CCL-2 (MCP-1) a potent regulator of monocyte/macrophage chemotaxis and invasion in various disease states is induced in response to CCL1. This stimulation of CCL-2 by CCL-1 was further validated by RT-PCR analysis. In corollary, targeted CCR8 siRNA inhibition down regulated CCL-2 expression further substantiating our findings. It is known that CCL2 protects human neuronal cells from tat-induced apoptosis and CCL1 is anti-apoptotic for thymic and leukemia cells. In the present study genes involved in oxidative stress are inhibited and those involved in protection against apoptosis are upregulated suggesting a common pathway for the two CC chemokines. Close examination of the role of CCL-1/CCR8 pathway in the regulation of CCL-2 and other angiogenic and/or apoptotic factors will provide important insights into vascular cell pathologies.