Analysis of chemokines and chemokine receptor expression in ovarian cancer ascites.

Purpose: Ascitic disease is a common occurrence in human ovarian cancer, but it is unclear how the cellular composition of ascitic fluid is determined. Because chemokines can determine host cell infiltration in solid ovarian cancer, we assessed CC chemokine protein and CC chemokine receptor expression in ovarian cancer ascites.

Experimental Design: We used reverse transcription-PCR and RNase protection assay to determine CC chemokine and chemokine receptor mRNA expression and ELISA to measure CC chemokine protein levels. Flow cytometry was used to identify cell populations and their chemokine receptor protein expression.

Results: mRNA for the CC chemokines CCL2, -3, -4, -5, -8, and -22 was expressed in cell isolates from ascites samples, and the corresponding proteins were detected in ascitic fluid. mRNA for CC chemokine receptors CCR1, -2a, -2b, -3, -4, -5, and -8 was detected in cells from ascites. Fluorescence-activated cell-sorting analysis showed variable numbers of macrophages and CD3(+) T lymphocytes (predominantly CD4(+)) within ovarian cancer ascites. CD14(+) macrophages within ascites consistently expressed protein for CCR1, -2, and -5. CCR1 was expressed by >60% of all T cells, but more CD4(+) than CD8(+) T cells expressed CCR2 and -5. A direct correlation was found between the CCL5 concentration and CD3(+) T-cell infiltration.

Conclusions: We conclude that there is a complex chemokine/chemokine receptor network in ovarian cancer ascites. However, associations between chemokine receptor expression, chemokine levels, and cell counts were limited.