Objective: To study the effect of wortmannin (WM), a PI3K/Akt inhibitor, on the proliferation and apoptosis of leukemia cells and the possible mechanism. Methods: Human leukemia cell line K562 was treated with different concentrations of WM. The proliferation of K562 cells was examined by MTT assay. DNA damage in K562 cells was examined by single cell gel electrophoresis assay, and apoptosis of K562 cells was detected by Annexin V-FITC/PI double-staining. The expressions of total Akt, phosphorate-Akt (p-Akt), and NF-κB p65 mRNA and protein were detected by RT-PCR and Western blotting, respectively. Results: WM inhibited the proliferation of K562 cells in a dose- and time-dependent manner, with the IC((50) value of 24 h being 25 nmol/L. WM also induced apoptosis of K562 cells in a dose-dependent manner. DNA damage in K562 cells was demonstrated by appearance of comet tail after treatment with WM, with the rate of DNA tail and the tail length being significantly higher than those in the control group (P<0.01). WM dose-dependently inhibited P-Akt and NF-κB p65, but not the total Akt, mRNA and protein expressions. Conclusion: WM can inhibit proliferation and induce apoptosis of K562 cells in a dose- and time-dependent manner, probably through down-regulation of phosphorate PI3K/Akt signal pathway and NF-κB expression.

Protein phosphorylation is one of the most common post-translational modification processes that play an essential role in regulating protein functionality.The Helicoverpa armigera single nucleopolyhedrovirus (HearNPv) orf2-encoded nucleocapsid protein HA2 participates in orchestration of virus-induced actin polymerization through its WCA domain,in which phosphorylation status are supposed to be critical in respect to actin polymerization.In the present study,two putative phosphorylation sites (232Thr and 250Ser) and a highly conserved Serine (245Ser) on the WCA domain of HA2 were mutated,and their phenotypes were characterized by reintroducing the mutated HA2 into the HearNPV genome.Viral infectivity assays demonstrated that only the recombinant HearNPV bearing HA2 mutation at 245Ser can produce infectious virions,both 232Tbr and 250Ser mutations were lethal to the virus.However,actin polymerization assay demonstrated that all the three viruses bearing HA2 mutations were still capable of initiating actin polymerization in the host nucleus,which indicated the putative phosphorylation sites on HA2 may contribute to HearNPV replication through another unidentified pathway.

10.3969/j.issn.1007-3969.2013.05.009

Tumor microenvironment (TME) plays a key role in the development and progression of tumors, such as pro?moting local drug resistance, immune escape, and distal metastasis. According to the TME of different individuals, accurate evaluation and selection of clinical medication can effectively control the malignant transformation of carcinoma in situ and metastatic cancer. At present, the main method to treat cancer is chemotherapy, TME can regulate the reaction of the tumor cells to the standard chemotherapy and target drug therapy, so the combination of the targeted TME therapy and chemothera?py will achieve better clinical efficacy. In this review, we summarized the mechanisms of TME in breast cancer, including ex?tracellular matrix, carcinoma-associated fibroblasts, carcinoma-associated macrophages, regulatory T cells and bone marrow mesenchymal stem cells, which providing a theoretical basis for the development of TME targeted therapy.

Objective To evaluate the sealing properties of three resin-based sealers,EndoREZ,RealSEAL and RealSEAL SE.Methods Forthy-eight extracted human anterior teeth with single root and canal were prepared using ProTaper files with crown-down technique to F3.The teeth were filled with three sealer respectively with hot gutta-percha vertical condensation technique simulating the clinical situation.Leakage quantity was detected using computerized fluid filtration meter with 10 samples in each group.The cross section morphology of apical parts of roots of 5 mm was observed with scanning electron microscope and transmission electron microscope in 3 samples of each group,respectively.Results The leakage quantity of EndoREZ,RealSEAL and RealSEAL SE were (2.61 ± 0.60),(1.43± 0.11) and (1.76 ± 0.18) μl/min,respectively.The gaps between the the sealer and the canal wall were increased in in order of RealSEAL,RealSEAL SE and EndoREZ.No obvious demineralized dentin under EndoREZ and the smear layer was not completed removed.The partly demineralized dentin was observed under RealSEAL and the smear layer was totally removed.The partly demineralized dentin was seen under RealSEAL SE and the majority of smear layer was removed.Conclusions Among the three resin-based sealers,RealSEAL has the best sealing properties,followed by RealSEAL SE and EndoREZ.