| Malignant tumor has become one of the major diseases endangering human health and even life, and its incidence increased year by year owing to the increasing elder. It is reported that the death rate of cancer may increase twice times in 2020. Hepatocellular carcinoma (HCC) is a very common malignant tumor in the world. It is also called ’cancer with Chinese characture’ because of its high incidence ratio. Nowadays, the usual ways to treat cancer are surgery and chemical therapy. It has become an important research direction in current tumor treatment searching for new chemotherapeutic drugs with low toxicity and high efficiency, because of HCC’s some characteristics, such as being easy to metastasis and to produce drug resistance.Pro. Zhu Weiming, leader of research group in Ocean University of China, carried out studies on Bisindole maleimide alkaloid structure modification and structure activity relationship, designed and synthesized a series of Bisindole maleimide compounds, which are with alkyl and nitrile chain substituted structure. This work was based on the antitumor activity of novel indole carbazole alkaloid found from marine microorganisms. Our previous studies have shown that these compounds can inhibit the growth and cause autophagy in series of tumor cell strains. Autophagy (type Ⅱ cell death) is a programmed cell death different from apoptosis.It is primary and usual biotic phenomenon. It can survive cells in condition such as starvation and invasion of virus. This topic explores the anti-tumor mechanism of BMA-155 in human hepatoma HepG-2 cells, and which provides a theoretical basis for its further clinical application.In our research, we clarified the effect of BMA-155 on apoptosis and its mechanism of human hepatocellular carcinoma HepG-2 cells. MTT essay was used to detect the inhibitory effect of BMA-155 on the growth of HepG-2 cells. The results showed that BMA-155 can inhibit growth of HepG-2 cells the in a time-and dose-dependent manner. We found that HepG-2 cells begin autophagy after 6 h BMA-155 treatment. With time goes on, the number and the size of autophagic vacuoles increased and it was almost up to the peak at 15 h observing by microscope and flow cytometry. To extend the BMA-155 treatment to 24 h, we found typical apoptotic features—apoptotic bodies’formation-- in HepG-2 cells, like shrinkage and dyeing matter accumulation, which was detected by DAPI staining and Amiexin V/PI double staining methods. In addition, the combined treatment of the specific autophagy inhibitor 3-MA and BMA-155 can significantly reduce the rate of apoptosis in cells compare to BMA-155 treatment alone. Further, we detected the changes of autophagy related genes NF-κB/p65 mRNA, p53 mRNA, Beclinl mRNA and apoptosis related gene Bax mRNA by RT-PCR. Finally, western blot experiments showed BMA-155 treatment can increase the expression of autophagy related protein LC3B and Beclin-1, as well as apoptosis related protein Bax expression, while decrease the expression of anti-apoptotic protein Bcl-2 expression. In addition, BMA-155 can promote the activation of NF-KB/p65 and p53, the inhibition of NF-κB/p65 can response to reduce the apoptosis induced by BMA-155 while increases the BMA-155 induced autophagy in cancer cells. Besides, we performed vivo experiments by establishing a model of subcutaneous transplantation tumor in nude mice, and treated with BMA-155 continuously for two weeks. The results showed that MBA-155 can also inhibit tumor growth in vivo. In conclusion, BMA-155 may induce autophagic apoptosis in vivo and in vitro, and autophagy plays a protective role in the process of cell death. Moreover, BMA-155 can activate the NF-KB/p65 pathway to control apoptosis.This is the first study to explore the activity and mechanism of Bisindole maleimide alkaloid (BMA-155) against liver cancer. The results show that BMA-155 is a promising anti-tumor lead compounds. Our study also provides a theoretical basis for the further research and development in the future. |
