Response in shape and size of individual P31 cancer cells to cisplatin andouabain: A computerized image analysis of cell halo characteristics duringcontinuous perfusion

Background: Volume regulation is essential for cellular functions, includin g cell death, such as apoptosis. Flow cytometry is standard for nonadherent cells, such as blood cells. Our aim was to explore image analysis methods to study adherent cancer cells of a solid tumor. Methods: P31 mesothelioma cells were perifused (40 min) and studied by phas e-contrast microscopy. A noise reduction of the cell contour was tested to more accurately yield the cell shape factor (SF). The optical halo around t he cell was analyzed for information about membrane blebbing. Results: The projected cell area (PCA) slowly increased under control perfu sion, the halo outside more than the halo inside. Cisplatin (apoptosis) cau sed an immediate increase in the PCA-halo outside(5.9 +/- 1.2 %, P < 0.01, 1-5 min) and the SF indicated decreased roundness (P < 0.05). The SF-halo i nside became more irregular than the outside, which was different from the control cells. The morphology reflected instant blebblng, and the cell bodi es showed fragmentation after about 20 min. Ouabain resulted in only small changes in PCA and SF, significantly different from both control and cispla tin conditions. Conclusions: Image analysis (PCA and SF) on perifused adherent cancer cells may serve as a tool to follow the sensitivity of cancer chemotherapy and t o study cell death patterns. (C) 2000 Wiley-Liss, Inc.