Cultivation of cancer cells in malignant pleural effusion and their use in a vascular endothelial growth factor study

Background and Aims: Cancer cells can be isolated from malignant pleural effusion (MPE). They may provide an ex- perimental system to explore the cell biology of lung cancer. Anti-VEGF antibody has been reported to efficiently control MPE, which contains a high concentration of VEGF; this suggests the important role of VEGF acting on MPE. We aimed to develop a method for culturing cancer cells from MPE and investigate the role of VEGF in MPE. Methods: Cancer cells in MPE were obtained from six patients and cultured using three different types of media, includ- ing (1) supernatant of MPE, (2) 1:1 mixture of supernatant and common culture medium, and (3) common culture medium only. We further co-cultured cancer cells with γ-irradiated mouse 3T3-J2 embryonic fibroblasts. Using co-cultured cells, we investigated the effect of VEGF on cancer cells and measured the amount of VEGF secreted from them. Results: Cancer cells were poorly maintained in three types of media, while well proliferated when co-cultured with 3T3- J2 feeder cells. VEGF didn’t affect cell proliferation. VEGF secreted from cancer cells didn’t reach to a concentration that may show an apparent biological effect. Conclusion: Proliferation of cancer cells in MPE requires a specific factor(s) in addition to those residing in the supernatant of MPE or conventional culture medium. Co-cultured cancer cells suggested a lack of proliferative effect of VEGF. The concentration of VEGF produced by cancer cells was not sufficient to exert a biological effect. Co-cultured cancer cells may provide a valuable experimental system for further cancer studies.