Published online May 15, 2019. doi: 10.4251/wjgo.v11.i5.377
Peer-review started: November 20, 2018
First decision: December 7, 2018
Revised: December 17, 2018
Accepted: January 3, 2019
Article in press: January 4, 2019
Published online: May 15, 2019
Colorectal cancer (CRC) is a major public health problem, representing the third cause of cancer deaths worldwide. Surgery and adjuvant chemotherapy are the main treatment for CRC. However, 40-50% of patients still die due to recurrence, metastases and drug resistance. In addition, severe side effects caused by chemotherapy agents lead to the deterioration of patient quality-of-life and therapeutic application. Therefore, the search for novel therapies has attracted worldwide attention. Qingjie Fuzheng granules (QFGs) is a traditional Chinese medicine formula with properties of anti-inflammation, antioxidative, antibacterial, immunity enhancement, and digestion promotion. QFGs has been widely used and found to be clinically effective in various cancer treatments, including CRC, and has few side effects. However, the precise mechanisms and molecular signaling pathways involved in the activity of QFGs’ anticancer effects have not been reported in the literature. In this study, we hypothesized that QFGs can inhibit the growth of CRC cells, and that its mechanism is closely related to one or more intracellular signal transduction pathways.
To better understand the mechanism underlying the potential anti-cancer effect of QFGs on the human CRC cell variants HCT-116 and HCT-8.
To elucidate the effect of QFGs on the biological function of CRC cells, and to investigate this biological function to explore the exact mechanism of QFGs effects on CRC cells.
First, cell viability and cytotoxicity were measured by performing MTT and LDH assays. We evaluated the role of QFGs in cell proliferation and apoptosis by assessing colony formation using Hoechst 33258. Second, cell cycle and apoptosis levels were measured by fluorescence-activated cell sorting. The expression levels of survivin, cyclin D1, CDK4, p21, Bax, Bcl-2, Fas, FasL, and cleaved-caspase-3/-8/-9 were measured by performing western blotting and caspase activity assays. Furthermore, inhibitors of caspase-3/-8/-9 were also used to elucidate the exact apoptosis pathway induced by QFGs in cancer cells. Finally, activation of the PI3K/AKT and ERK signaling pathways was examined using the western blot assay to investigate the possible mechanism.
MTT and LDH assays revealed that after 0.5-2.0 mg/mL of QFGs treatment, cell viability was reduced by (6.90% ± 1.03%)–(59.70% ± 1.51%) (HCT-116; P < 0.05) and (5.56% ± 4.52%)–(49.44% ± 2.47%) (HCT-8; P < 0.05). Cytotoxicity was increased from 0.52 ± 0.023 to 0.77±0.002 (HCT-116; P < 0.01) and from 0.56 ± 0.054 to 0.81 ± 0.044 (HCT-8; P < 0.01) compared with non-QFGs treatment groups. Additionally, colony formation and Hoechst 33258 staining assays showed that QFGs inhibited proliferation and induced apoptosis in CRC cells. QFGs also increased the expression levels of Bax, Fas, and FasL, decreased the level of Bcl-2, and stimulated the activation of caspase-3/-8/-9, which were revealed by western blot and caspase activity assays. In contrast, upon adding the three caspase inhibitors, the suppression effect of QFGs on cell viability and apoptosis were markedly inhibited. Moreover, QFGs suppressed the phosphorylation levels of PI3K, AKT and ERK.
These results demonstrated that QFGs inhibit CRC cell proliferation and induce apoptosis by suppressing the PI3K/AKT and ERK signaling pathways. This indicated that QFGs are a potential new therapeutic treatment for CRC and other cancers.
Traditional Chinese Medicine (TCM) is important for the treatment of many cancers and has a long history of clinical use. If the effects and mechanisms of TCM are further elucidated, it may provide a more effective treatment for many cancer types.