OBJECTIVETo explore the relationship between the expression of transcription factor TWIST and apoptosis of Hep-2 cells induced by paclitaxel.

METHODSMorphological changes of Hep-2 cells were observed by reserved microscopy and acridine orange cytochemistry staining. Viability of Hep-2 cells treated with various concentrations of paclitaxel was detected by MTT assay. Apoptosis was examined by flow cytometry. The expressions of transcription factor TWIST at both mRNA and protein level in response to paclitaxel at 24 h, 48 h and 72 h were then examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively.

RESULTSTypical morphological changes of apoptotic cells, i.e., cellular rounding-up, cytoplasmic contraction, chromatin condensation and, particularly, apoptotic body, the main morphological characteristic of apoptosis, were observed by reserved microscopy and acridine orange cytochemistry staining. The cell surviving rates significantly decreased in a concentration- and time-dependent manner as evidenced by MTT assay (P < 0.05). Percent of apoptosis after 24 h, 48 h or 72 h paclitaxel-treatment was (22.6 +/- 5.3)%, (38.7 +/- 7.9)% and (52.4 +/- 14.3)%, respectively, whereas the percent of control was (9.85 +/- 5.83)%. There existed a statistically significant difference between treatment and control (F = 12.621, P < 0.05). The expression of TWIST at both mRNA and protein levels for 24 h, 48 h or 72 h in the paclitaxel-induced apoptosis of Hep-2 cells were decreased by 16.7%, 46.8%, 76.9% (F = 10.407, P < 0.05) and 16.4%, 33.6%, 69.6% (F = 18.013, P < 0.05) respectively.

CONCLUSIONSTWIST, which is significantly decreased in expression in response to paclitaxel in Hep-2 cells, may play a pivotal role in paclitaxel-induced apoptosis of Hep-2 cells.