Knockdown of EphB3 inhibits cell proliferation partly through the AKT signaling pathway and represses epithelial-mesenchymal transition in esophageal squamous cell carcinoma.

Background: To investigate the role and mechanism of erythropoietin-producing hepatocyte receptor B3 (EphB3) in cancer of esophageal squamous cells. Methods: EphB3 expression in esophageal carcinoma squamous tissue and cell lines was determined by immunohistochemistry, western blotting and qRT-PCR. The viability, invasion and migration of cells were assessed by Transwell assay, formation of colonies, CCK-8, and healing of wounds, respectively. Flow cytometry analysis was employed to evaluate the actions of EphB3 on the activity of the cell cycle and the degree of apoptosis. The activity of EphB3 on the growth of tumors in vivo was examined in a mouse xenograft model. Results: EphB3 was highly expressed in esophageal squamous cell cancer tissue and was positively correlated with cell differentiation, metastasis in lymph node and the TNM stage. Patients with higher EphB3 expression had poorer prognosis in 3-year overall survival rate. EphB3 also overexpressed in esophageal squamous cell cancer cell lines. Knock down of EphB3 expression suppressed proliferation, migration and the invasion of cells in vitro and was shown to delay the growth of tumors in vivo. Silencing of EphB3 reduced the expression of pAKT, cyclinD1 and altered the epithelial-mesenchymal transition (EMT) process. Furthermore, AKT signal pathway agonist SC79 reversed EphB3 downregulation-mediated inhibition of cell proliferation, migration, invasion and EMT process. Conclusions: EphB3 knockdown inhibited the proliferation of esophageal squamous cell cancer partly through the AKT signaling pathway and repressed cell migration and invasion via EMT reversion. The findings of the study suggested that EphB3 might be a novel target for the therapy of esophageal carcinoma.

The Synergistic Effects of Celastrol in combination with Tamoxifen on Apoptosis and Autophagy in MCF-7 Cells.

Breast cancer is one of the most common cancers among females and is associated with high mortality and morbidity rates. Several studies have demonstrated that combination treatments with natural products and tamoxifen can improve the sensitivity and cytotoxicity of oestrogen-positive breast cancer cells in response to tamoxifen. Celastrol, a triterpene from traditional Chinese medicine, has been proven to exert significant anticancer effects on various cancers. Our study is aimed at exploring the interactive antitumour effects of celastrol combined with tamoxifen and the potential underlying anticancer mechanisms in MCF-7 cells. The results from MTT assays, isobolographic analyses, and clonogenic cell survival assays revealed that a combination of celastrol and tamoxifen exerted synergistic cytotoxic effects in MCF-7 cells. The results from Annexin V/PI staining and flow cytometry analysis suggested that celastrol enhanced tamoxifen-mediated apoptosis. In addition, exposure to a combination of celastrol and tamoxifen inhibited cell proliferation by causing G1 phase cell cycle arrest. Moreover, the distribution of LC3 was monitored by immunofluorescence, and the changes in the LC3II and P62 levels detected by western blot analysis suggested that celastrol in combination with tamoxifen triggered autophagy. Furthermore, the decrease in p-Akt and p-mTOR in MCF-7 cells, along with the increase in the autophagy marker proteins LC3II and P62, suggested that the Akt/mTOR pathway might be involved in the triggering of cell autophagy by the combination treatment. However, in an MCF-7-implanted nude mouse model, it was possible to detect significantly decreased tumour volumes and tumour weights and decreased p-Akt and p-mTOR protein expression in the celastrol+tamoxifen group. Therefore, our study provides the first evidence that celastrol combined with tamoxifen exerts synergistic anticancer effects by inducing apoptosis and autophagy in MCF-7 cells. Considering the urgent need for novel therapeutic strategies in anticancer therapy, this combinatorial approach is worthy of further investigation.

Novel anti-CD38 humanized mAb SG003 possessed enhanced cytotoxicity in lymphoma than Daratumumab via antibody-dependent cell-mediated cytotoxicity.

BACKGROUND: In vivo use of monoclonal antibodies has become routine clinical practice in the treatment of human cancer. CD38 is an attractive target, because it has double roles, as a receptor and an ectoenzyme. Daratumumab, an anti-CD38 antibody, is currently in the clinical trials for multiple myeloma. RESULTS: Here we obtained a humanized anti-CD38 antibody, SG003, using SDR-grafting method. SG003 possessed stronger antigen binding activity than Daratumumab, and its epitope was far from that of Daratumumab, an anti-CD38 antibody currently in the clinical trials for multiple myeloma; besides, SG003 showed enhanced antibody-dependent cell-mediated cytotoxicity function and in vivo inhibitory efficacy of tumor growth in xenograft mice model. CONCLUSION: SG003 seemed to be a good option to improve the curative effect of CD38-related cancers.