7-Xylosyl-10-deacetylpaclitaxel is a natural hydrophilic paclitaxel derivative. 
It has long been used in Chinese clinics to treat cancer. In order to further 
explore the underlying intracellular target of 7-xylosyl-10-deacetylpaclitaxel 
towards the PC-3 cell line, the ultra-structural morphology of mitochondria, the 
intracellular Ca (2+), the intracellular ATP, the intracellular hydrogen 
peroxide and pro-apoptotic Bax and Bcl-2 protein expression were measured. 
Additionally, the changes of mitochondrial morphology and membrane potential ( 
ΔΨm) were analyzed by atomic force microscopy (AFM) and flow cytometry, 
respectively. Our results suggest that the intracellular target of 
7-xylosyl-10-deacetylpaclitaxel may be the mitochondrial permeability transition 
pore (mPTP). To further evaluate this hypothesis, we assessed the effect of a 
specific mPTP inhibitor (cyclosporine A) on the toxic action of 
7-xylosyl-10-deacetylpaclitaxel. The 7-xylosyl-10-deacetylpaclitaxel-induced 
decrease in mitochondrial inner transmembrane potential (ΔΨm) was abolished by 
the addition of cyclosporine A (CsA) in PC-3 cells, indicating that 
7-xylosyl-10-deacetylpaclitaxel may target mPTP. Furthermore, treatment with 
7-xylosyl-10-deacetylpaclitaxel increased ROS levels in PC-3 cells. This effect 
was counteracted by 10 µM cyclosporine A. These data indicate that oxidative 
damage is involved in mPTP.