High throughput characterization of anti-cancer compounds by means of cellular imaging and automatic image analysis. Free

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In vitro cell observations have been extensively used for many years in a wide range of applications, including cell migration analysis and drug testing. Nowadays computer assisted-microscopy allows the handling of considerably large amounts of image data acquired during experiments lasting over several hours or several days. This makes possible the detection of less frequent cell events, such as division or death. Several of our in-house developed applications show that the combination of time-lapse video-microscopy with adapted image analysis methods constitutes an efficient tool for the broadest screening of cell behavior. This approach delivers detailed information characterizing cell migration and cell growth processes. Depending on the biological models used, motility and invasion properties can also be readily analyzed. In the present study, we similarly report that cell growth can be detailed in terms of cell proliferation and death which in turn can be assigned on the basis of morphological features to apoptotic or autophagic processes. The main advantage of this approach is to allow fast observation and qualification of the effects of anti-cancer compounds on cell behavior. Not only does this screening identify a subset of interesting candidates among 10s of compounds but also gives clues on the mechanism of drug action (MOA), and thus optimizes the selection of further time-consuming and expensive biological evaluations required to elucidate the true MOA. Using this approach, it was found that UNSB1450, an hemi-synthetic cardenolide (Vanquaquebeke et al., J Med Chem 2005) impairs both U373 glioblastoma cell motility and proliferation. While a UNSB1450 concentration of 10 nM significantly increased the duration of cell division, 100 nM abolished cell division in a large number of cases. When cell divisions were successful, the separation rate of the daughter cells significantly decreased in compound-treated cells (10 or 100 nM) compared to controls. A decrease in U373 cell growth under treatment was confirmed by means of the colorimetric MTT assay. Furthermore, more specific analyses revealed cytotoxic pro-autophagic effects of this compound, as well as a disorganization of the actin cytoskeleton of the cells which failed to complete cytokinesis.

In conclusion, cellular imaging enables monitoring of cell cultures during long-term experiments. Adapted methods of cell imaging provide useful tools for cell movement and cell morphology analysis, enabling detection and characterization of cell events, such as migration, division and death.