Triptolide Induces Apoptosis and Synergizes with Cisplatin in Cisplatin-Resistant HNE1/DDP Nasopharyngeal Cancer Cells

Wang, X.; Zhang, J.-J.; Sun, Y.-M.; Zhang, J.; Wang, L.-R.; Li, Jian-Chun; Liu, Hao

doi:10.14712/fb2015061050195

Folia Biologica > Archive > 2015, Vol. 61 > Issue 5 > Triptolide Induces Apoptosis and…

Fol. Biol. 2015, 61, 195-202

https://doi.org/10.14712/fb2015061050195

Triptolide Induces Apoptosis and Synergizes with Cisplatin in Cisplatin-Resistant HNE1/DDP Nasopharyngeal Cancer Cells

X. Wang¹, J.-J. Zhang², Y.-M. Sun¹, J. Zhang¹, L.-R. Wang³, Jian-Chun Li¹, Hao Liu¹

¹Faculty of Pharmacy, Bengbu Medical College, Bengbu Anhui, China
²Department of Medical Oncology, the First Affiliated Hospital of Bengbu Medical College, Bengbu Anhui, China
³Department of Pharmaceutical Sciences, School of Pharmacy, Computational Chemical Genomics Screening Center, Pittsburgh, Pennsylvania, USA

Received March 2015
Accepted June 2015

The purpose of the study was to evaluate the anti-tumour effects of triptolide (TPL) and of the combination of TPL and cisplatin (DDP) in DDPresistant HNE1/DDP nasopharyngeal cancer (NPC) cells and to reveal the possible mechanisms. HNE1/ DDP cells were treated with TPL and/or DDP. Cell proliferation was examined by 3‑(4,5‑dimethylthiazol‑2‑yl) ‑2,5‑diphenyltetrazolium bromide (MTT) assay and colony-forming assay; the combination index of the synergism between TPL and DDP was calculated. Cell morphological changes were observed under a microscope. Reactive oxygen species (ROS) and apoptosis rate were determined by flow cytometry. 5,5’,6,6’-tetrachloro-1,1’,3,3’-tetrethyl benzimidalyl carbocyanine iodide (JC-1) staining was used to determine mitochondrial membrane potential (MMP). Protein expression was analysed by Western blot, including Bax, caspase-9, Bcl-2, Mcl-1. TPL had an obvious anti-tumour effect and exhibited synergistic cytotoxicity with DDP on DDP‑resistant HNE1/DDP cells. TPL induced HNE1/DDP cell apoptosis via inducing ROS generation. This effect was abolished by the inhibitor of ROS, N‑acetyl‑L‑cysteine (NAC). TPL alone or combined with DDP could lower MMP significantly. Western blot showed that TPL alone or in combination with DDP increased expression of Bax and caspase-9, but reduced expression of Bcl-2 and Mcl-1. We conclude that TPL could induce cell apoptosis and synergize with DDP by regulating ROS generation and mitochondrial pathways in HNE1/DDP cells. This indicates that TPL may be effective in DDP‑resistant NPC, either alone or combined with DDP.

Keywords

triptolide, nasopharyngeal cancer, cisplatin resistance, reactive oxygen species, apoptosis.

Funding

The present study was supported by the National Natural Science Foundation of China (81372899), the Project of Natural Science Research of the Education Department of Anhui Province, China (KJ20154B065by) and the Key Project of Natural Science Research of Bengbu Medical College of Anhui Province, China (BYKY1409ZD).