Cistanche tubulosa phenylethanoid glycosides induce apoptosis in H22 hepatocellular carcinoma cells through both extrinsic and intrinsic signaling pathways

Pengfei Yuan,Adila Aipire,Xinhui Wang,Jinyu Li,Yijie Li,Yi Yang,Jinyao Li,Lijie Xia

doi:10.1186/s12906-018-2201-1

Abstract

BackgroundCistanche tubulosa (Schenk) R. Wight is a traditional Chinese medicine that parasitizes the roots of the Tamarix plant and has been used to treat male impotence, sterility, body weakness, and as a tonic. However, its antitumor effect on hepatocellular carcinoma is still elusive. Here, we investigated the antitumor effect of C. tubulosa phenylethanoid glycosides (CTPG) on H22 hepatocellular carcinoma cells both in vitro and in vivo and its mechanisms.MethodsThe morphology, viability, apoptosis, cell cycle and mitochondrial membrane potential (Δψm) of H22 cells were analyzed by inverted microscopy, MTT assay and flow cytometry, respectively. The expression and activation of proteins in apoptosis pathway were detected by Western blot. The in vivo antitumor effect was evaluated in tumor mouse model established using male Kunming mice.ResultsCTPG treatment significantly suppressed H22 cell growth in a dose- and time-dependent manner, which was correlated with the increased apoptosis and cell cycle arrest at G0/G1 and G2/M phases. Moreover, the chromosomal condensation was observed in CTPG-treated H22 cells. CTPG treatment significantly increased Bax/Bcl-2 ratio, reduced Δψm and enhanced the release of cytochrome c. The levels of cleaved caspase-8 and caspase-9 in both extrinsic and intrinsic signaling pathways were significantly increased that sequentially activated caspase-7 and -3 to cleave PARP. Finally, CTPG inhibited the growth of H22 cells in mice and improved the survival rate of tumor mice.ConclusionsThese results suggested that CTPG suppressed H22 cell growth through both extrinsic and intrinsic apoptosis pathways.

Highlights

Detection of apoptosis H22 cells were treated with different concentrations of C. tubulosa phenylethanoid glycosides (CTPG) (0, 100, 200, 300 and 400 μg/ml) or 0.3% DMSO for 24 h, and stained with Annexin VFITC/Propidium iodide (PI) Apoptosis Detection Kit (YEASEN, China) according to the manufacturer’s instructions
Detection of mitochondrial membrane potential H22 cells were treated with different concentrations of CTPG (0, 200 and 400 μg/ml) for 24 h, and stained with the membrane-permeable JC-1 dye (Beyotime,China) for 20 min at 37 °C
CTPG reduced the viability of H22 cells in vitro In order to explore antitumor effect of CTPG on hepatocellular carcinoma (HCC), H22 cells were treated with different concentrations of CTPG (0, 100, 200, 300 and 400 μg/ml) in vitro

Summary

Introduction

Its antitumor effect on hepatocellular carcinoma is still elusive. We investigated the antitumor effect of C. tubulosa phenylethanoid glycosides (CTPG) on H22 hepatocellular carcinoma cells both in vitro and in vivo and its mechanisms. Liver cancer ranked sixth for cancer incidence and fourth for cancer deaths worldwide It ranked fourth for cancer incidence and first for cancer mortality in countries with low sociodemographic index [1]. Less than 30% of patients with HCC met the criteria of curative hepatic resection and the overall 5-year survival rate is still as low as 35-50% due to the high recurrence rate [4, 5]. A molecular targeted drug, has been approved by FDA as the first-line treatment for advanced HCC. It is urgent to develop new drugs or strategies against HCC

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