Nadia MatterALMhana^1,, Israa Zainal², Nahi Y. Yaseen³

C-C chemokine receptor like 2 (CCRL2) is a member of the atypical chemokine receptor family; it is a hepta helical transmembrane receptor, expression of which has been shown on almost all human hematopoietic cells. CCRL2 were previously considered to be orphan receptor and as a receptor presenting its chemo attractant ligand to functional receptors. The function and expression of CCRL2 in cancer is not understood at present. Here, we investigated the expression of CCRL2 as well as the effects on cellular proliferation resulting from their knockdown in three cancer cell lines include: human cerebral glioblastoma multi form (ANGM, at passages 75-84), human cervical cancer (HeLa, at 70 passages), and human pelvic rhabdomyosarcoma (RD, at 75 passages) cell lines. In addition, all cell lines were screened for mRNA expression of CCRL2 by reverse transcription polymerase chain reaction (RT-PCR). Cell lines with detectable expression were used for knockdown experiments; and the respective influence after transfection with small interfering RNA (siRNA) concentrations (2,3,4,5,6,7 and 8) ρmol for (24 , 48 and 72) hour were determined for both CCRL2 gene and the house keeping gene GAPDH as control. The Knockdown of CCRL2 was highly successful; the expression of CCRL2 was down-regulated by over 76.0%, 89.6% and 80.7% after transfection for 48 hour to (ANGM, HeLa and RD) cell lines respectively. The results also indicated that in the CCRL2 absence there was a significant decrease in the cell proliferation, suggesting a pro-tumoral effect of CCRL2. The potential roles of CCRL2 as a novel therapeutic target and biomarker warrant further investigations.

chemokine receptor, CCRL2, gene expression, gene silencing, human cancer cell lines