Antiproliferative and Proapoptotic Effects of a Protein Component Purified from Aspongopus chinensis Dallas on Cancer Cells In Vitro and In Vivo

Aspongopus chinensis Dallas is used as a traditional Chinese medicine. In China, clinical evidence suggests that it has anticancer activity. However, the anticancer active components are not fully elucidated. In the present study, we purified an anticancer active component (named CHP) from A. chinensis. To gain a comprehensive insight into the protein components, shotgun proteomic analysis was conducted. The anticancer active protein band was cut from the sodium dodecyl sulphate-polyacrylamide gel electrophoresis gel and digested with trypsin to generate peptide mixture. The peptide fragments were then analysed by liquid chromatography tandem mass spectrometry; 18 proteins were identified. In addition, we evaluated the effects of CHP on the proliferation and apoptosis of two human gastric cancer cell lines (SGC-7901 and BGC-823). The cultured cells were treated with CHP at concentrations of 20, 30, and 40 μg/mL. Inhibition of cell growth was determined by the MTT assay. Hoechst 33258 staining was adopted to detect apoptosis morphologically. Apoptotic cells were quantified by Annexin V-FITC/propidium iodide staining and flow cytometry. Tumour growth was assessed by subcutaneous inoculation of 4T1 cells into BALB/c mice. There was a concentration- and time-dependent decrease in the proliferation of both cell lines at CHP concentrations of 20–40 μg/mL. Apoptotic characteristics, such as karyopyknotic pyknic hyperfluorescence bolus and nuclear fragmentation, were observed in both the cell lines by Hoechst 33258 staining. Flow cytometry showed that CHP induced significant (P < 0.01) concentration-dependent apoptosis of SGC-7901 cells. In vivo assay showed that CHP can partially inhibit tumour growth derived from 4T1 cells in vivo. The present study is the first to report that CHP in A. chinensis inhibits the proliferation of cancer cell lines via the suppression of cancer cell proliferation and acceleration of apoptosis.