Differential expression of CD40 and CD95 in ovarian carcinoma.

Purpose: The role of CD95 (Fas) as a mediator of apoptosis has been well documented. CD40 ligation has been recently shown to initiate apoptosis and modulate CD95 mediated apoptosis in normal and some neoplastic tissues. Here we report the expression of CD95 and CD40 in cryopreserved cell suspensions from ovarian cancer associated ascites, fresh primary and recurrent ovarian carcinoma (OVCA) specimens, and ten established ovarian cancer cell lines. The effect of CD95 and CD40 receptor binding on apoptosis is described in two cell lines.

Experimental Design: Ascites specimens, fresh primary and recurrent OVCA specimens were dissociated to single cell suspensions. Expression of CD95 and CD40 was analyzed using flow cytometry. Apoptosis was determined via annexin uptake by flow cytometry following incubation with anti-CD95 antibody, CH11 and trimeric CD40L.

Results: Ascites showed the highest expression of both CD95 and CD40. Recurrent OVCA, in contrast, expressed low levels of CD95 and CD40. Primary OVCA showed moderate expression of both receptors. CD40 expression in ascites was significantly greater when compared to solid specimens (p < 0.05). Both CD40 and CD95 were strongly expressed in eight of ten cell lines studied. Binding of CD40L did not influence CD95 mediated apoptosis.

Conclusions: CD40 is ubiquitously expressed in ovarian carcinomas and expression differs between ascites and solid tumor. There may be differential expression of both CD40 and CD95 in recurrent vs primary ovarian carcinoma, which may contribute to increased clinical malignancy of recurrent disease. In contrast to other epithelial malignancies, CD40 ligation does not appear to modulate CD95 mediated apoptosis.