ABSTRACT
BACKGROUND: Most Epstein-Barr virus (EBV)-positive cells lose the EBV episomes upon prolonged propagation. PURPOSE: The purposes of this study were to establish a simple cell model for nasopharyngeal carcinoma (NPC) research by introducing a plasmid with the EBV genome into NPC cells and then to investigate the resulting changes in malignant biological behaviour and NPC-associated signalling pathways. METHODS: HONE1 NPC cells were transfected with F-factor plasmids including the EBV genome (HONE1-EBV cells). Then cell proliferation, migration, cell cycle distribution and apoptosis were evaluated in vitro by using CCK8, transwell and flow cytometry assays respectively. EBV-encoded proteins and cell signal tranducting proteins were detected by western blot assays. EBV-encoded RNAs were detected by in situ hybridization. EBV particles were assayed by transmission electron microscope (TEM). The morphology of cells were detected by immunofluorescence assays for alpha-tubulin. RESULTS: Latent membrane protein 1 (LMP1), latent membrane protein 2A (LMP2A), Epstein-Barr nuclear antigen 1 (EBNA1) and EBV-encoded small RNAs (EBERs) were successfully expressed in HONE1-EBV cells. No EBV particles were founded by TEM. Introduction of the EBV genome significantly promoted proliferation, cell cycle progression and migration and inhibited apoptosis in HONE1 cells. Immunofluorescence assays showed that the morphology of HONE1-EBV cells changed into spindle. Furthermore, EBV genome introduction significantly inhibited the JAK/STAT signalling pathway, while it activated the PI3K-AKT and NF-κB signalling pathways in HONE1 cells. CONCLUSION: These findings suggest that F-factor plasmid-mediated EBV genome introduction was successful in constructing an EBV positive cell model, which showed deteriorated biological behavior and activated NPC-associated signalling pathways. This model can serve as a good tool for studying EBV in NPC, but the subtle differences in cancer-associated pathways must be considered.
ABSTRACT
The phosphatidylinositol 3-kinase α (PI3Kα) was genetically validated as a promising therapeutic target for developing novel anticancer drugs. In order to explore the structure-activity correlation of benzothiazole series as inhibitors of PI3Kα, comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA) were performed on 61 promising molecules to build 3D-QSAR models based on both the ligand- and receptor-based methods. The best CoMFA and CoMSIA models had a cross-validated coefficient r(cv)(2) of 0.618 and 0.621, predicted correlation coefficient r(pred) (2) of 0.812 and 0.83, respectively, proving their high correlative and predictive abilities on both the training and test sets. In addition, docking analysis and molecular dynamics simulation (MD) were also applied to elucidate the probable binding modes of these inhibitors at the ATP binding pocket. Based on the contour maps and MD results, some key structural factors responsible for the activity of this series of compounds were revealed as follows: (1) Ring-A has a strong preference for bulky hydrophobic or aromatic groups; (2) Electron-withdrawing groups at the para position of ring-B and hydrophilic substituents in ring-B region may benefit the potency; (3) A polar substituent like -NHSO(2)- between ring-A and ring-B can enhance the activity of the drug by providing hydrogen bonding interaction with the protein target. The satisfactory results obtained from this work strongly suggest that the developed 3D-QSAR models and the obtained PI3Kα inhibitor binding structures are reasonable for the prediction of the activity of new inhibitors and be helpful in future PI3Kα inhibitor design.
