Recently, Yin Huiyong, a researcher at the Key Laboratory of Nutrition Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, China Academy of Sciences, published a research paper online, pointing out that polyphenol proanthocyanidins -B2 can inhibit the proliferation of liver cancer cells and the canceration of liver cells by directly binding to and inhibiting AKT activity.

Procyanidin -B2(OPC-B2) is a polyphenol active substance extracted from peanut red coat. It is a new type of AKT allosteric inhibitor, which can directly bind AKT and inhibit its phosphorylation, thus exerting its anti-tumor activity. Lys297 and Arg86 on AKT protein play an important role in the combination of OPC-B2 and AKT. This may provide a potential therapeutic strategy for the clinical treatment of liver cancer.

OPC-B2 was isolated from peanut skin, and its chemical structure was characterized by comparing it with standard compounds on the market by high resolution mass spectrometry. In order to detect the effect of OPC-B2 on the proliferation of HCC cells, researchers treated Huh7 cells with different concentrations in the determination of colony formation and proliferation. OPC-B2 has a strong inhibitory effect on the proliferation and colony formation of tumor cells in a time-and dose-dependent manner. Interestingly, OPC-B2 showed anti-tumor effects on several hepatocellular carcinoma cell lines with different carcinogenic characteristics: early HCC cell SMMC-772 1 cell, well-differentiated Hep 3B cell and highly metastatic LM3 cell. Although OPC-B2 showed different effects on different cell lines, the IC50 of OPC-B2 on Hep3B reached about 12.5μg/ ml(2 1μM). In a word, these results show that OPC-B2 has obvious inhibitory effect on the proliferation of HCC tumor cells in vitro.

Next, the researchers explored the anti-tumor effect of OPC-B2 in vivo by using a xenograft tumor growth model. After subcutaneous injection of Huh7 cells into nude mice (mice with congenital thymic defects), the mice were randomly divided into three groups: control group, 10 mg/kg and 30 mg/kg. OPC-B2 was injected intraperitoneally every two days at the dosage of 10 and 30 mg/kg, and the tumor size was recorded. After killing mice on the 28th day, the researchers observed that OPC-B2 showed a strong anti-tumor effect in a dose-dependent manner. Compared with the control group, the tumor size, tumor volume and tumor weight in OPC-B2 and 30 mg/kg treatment groups decreased by 60%. To sum up, OPC-B2 has a significant inhibitory effect on HCC cell proliferation and tumor growth in vitro and in vivo.