Metformin has been used for the treatment of type II diabetes mellitus for decades. Recently, used of metformin in the therapy of diverse human cancer types has received widespread attention, while the underlying mechanisms have been not fully elucidated. In the current study, 5-ethynyl-20-de-oxyuridine assay to detect cell proliferation, flow cytometry to detect apoptosis, scratch wound healing and Transwell migration assay to detect cell migration capacity. The current study reported that metformin inhibited cell proliferation and migration, and promoted apoptosis in ovarian cancer cells, particularly under normoglycemic conditions in vitro. Metformin treatment significantly promoted the phosphorylation of AMP-activated protein kinase (AMPK), and reduced histone H3 lysine 27 trimethylation (H3K27me3) and polycomb repressor complex 2 (PRC2) levels. Additionally, overexpression of EZH2 to increase H3K27me3 abrogated the effect of metformin on the cell proliferation, migration and apoptosis in SKOV3 and ES2 cells. Similar to metformin, another AMPK agonist, 2-deoxy-D-glucose, reduced the H3K27me3 level and PRC2 expression. In cells pretreated with Compound C, an AMPK inhibitor, metformin was not able to induce AMPK phosphorylation or reduce H3K27me3. Metformin-mediated AMPK activation and H3K27me3 inhibition were more robust in cells exposed to low glucose (5.5 mM) compared with those exposed to high glucose (25 mM). These findings implicate H3K27me3 repression mediated by AMPK phosphorylation in the antitumor effect of metformin in ovarian cancer, indicating that metformin alters epigenetic modifications by targeting PRC2 and supports the use of metformin in treatment of patients with epithelial ovarian cancer without diabetes.

Hepatocellular carcinoma (HCC) has an increasing incidence worldwide, and the global 5-year survival rate ranges from 5-30%. In China, HCC seriously threatens the nation's health; the incidence of HCC ranks fourth among all theriomas, and the mortality rate is the third highest worldwide. The main therapies for HCC are surgical treatment or liver transplantation; however, most patients with HCC will experience postoperative recurrence or metastasis, eventually resulting in mortality. As for advanced or unresectable HCC, the current appropriate treatment strategy is transarterial chemoembolization; however, limited therapeutic effect and natural or acquired drug resistance affect the efficacy of this approach. Previous studies have demonstrated that PD-L1 expression on host cells and myeloid cells plays an important role in PD-L1 blocked-mediated tumor regression. Thus, further research on programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) is required. Countries including the United States, France, Britain and China have developed PD-1/PD-L1 blockers, including nivolumab, pembrolizumab, cemiplimab, atezolizumab, avelumab, durvalumab, toripalimab, sintilimab and camrelizumab. Notably, all of these blockers have therapeutic effect and influencing factors in HCC. Factors that influence the clinical outcome of PD-1 have also been discovered, such as inflammatory genes, specific receptors and signaling pathways. The discovery of these factors will help to identify novel methods, such as combination treatment, to decrease the influence of other factors on the efficacy of PD-1/PD-L1. Sorafenib and lenvatinib have been approved for first-line treatment for patients with advanced HCC. When first-line treatment frequently fails, pembrolizumab and ipilimumab plus nivolumab are used following sorafenib (but not lenvatinib) treatment in advanced HCC. Thus, tumor immunotherapy using PD-1/PD-L1 blockers exhibits promising outcomes for the treatment of HCC, and more novel PD-1/PD-L1 inhibitors are being developed to fight against this disease. The present review discusses the clinical results and influencing factors of PD-1/PD-L1 inhibitors in HCC to provide insight into the development and optimization of PD-1/PD-L1 inhibitors in the treatment of HCC. Contents 1. Introduction 2. Listed drugs 3. Listed drugs in China 4. Influencing factors 5. Discussion 6. Conclusions

This study investigated the effect of epigenetic modification of maspin on extravillous trophoblastic function. The mRNA expression of maspin in placentae from normotensive and preeclamptic pregnant women was detected by RT-PCR. TEV-1 cells, a human first-trimester extravillous trophoblast cell line, were cultured and treated with CoCl(2) (300 μmol/L) to induce chemical hypoxia and with 5-aza (500 nmol/L) to induce demethylation. The mRNA expression of maspin in TEV-1 cells subjected to different treatments was determined by RT-PCR, and the proliferative and migratory abilities of TEV-1 cells were assessed by cell counting kit-8 (CCK-8) and Transwell assays. Our results showed that the maspin mRNA expression level in placentae from preeclamptic women was much higher than that from normotensive women. CoCl(2) or 5-aza could up-regulate the mRNA expression of maspin and significantly suppress the proliferation and migration of TEV-1 cells. It was concluded that the epigenetic modification in promoter region of maspin contributes to incomplete trophoblast invasion, which offers a novel approach for predicting and treating placental dysfunction.