[Detection of apoptosis exposed to 10-hydroxycamptothecin in T24 human urinary bladder cancer cells]

To study whether 10-hydroxycamptothecin (HPT) can induce apoptosis in bladder cancer cell and establish methods for detecting apoptotic cells.

Human urinary bladder cancer cell line (T24) was exposed in vitro to different concentrations of 10-hydroxycamptothein for various lengths of time. Flow cytometry, Hochest 33258 and Hematoxylin staining were used to determine the induction of apoptosis after use of HPT. DNA gel analysis was also carried out to detect DNA fragmentation.

Cell shrinage, nuclear fragmentation and condensed chromosomes showed that apoptosis can be induced by HPT within the concentration of 0.01 - 10 microg/ml. The flow cytometry analysis showed that the percentage of apoptotic cells were related to the concentration and the time of induction. T24 cell line exposed to HPT experienced internucleosomal DNA fragmentation by producing a typical ladder pattern on agarose gel electrophoresis. The detection of minimum exposure time for HPT-induced apoptosis in T24 cells showed that 3 hours of exposure to HPT were enough to trigger internucleosomal DNA fragmentation. Compared to Hochest 33258 staining, Hematoxylin staining was more easy, rapid and accurate to detect apoptosis.

The induction of apoptosis exposed to HPT in T24 human urinary bladder cancer cells is a good model for further studying urinary bladder cancer. Hematoxylin staining is a useful method for detecting apoptosis.