MiR-34c suppresses tumor growth and metastasis in nasopharyngeal carcinoma by targeting MET.

Our previous microarray analysis indicated that miR-34c was downregulated in nasopharyngeal carcinoma (NPC). However, little is known about the function and molecular mechanism of miR-34c in NPC. In this study, miR-34c was found to be significantly downregulated in NPC cell lines and clinical tissues. Ectopic expression of miR-34c suppressed NPC cell viability, colony formation, anchorage-independent growth, cell migration and invasion in vitro, and inhibited xenograft tumor growth and lung metastasis in vivo. MET proto-oncogene (MET) was identified as a direct target of miR-34c using luciferase reporter assays, quantitative RT-PCR, western blotting and immunofluorescent staining. Overexpression of miR-34c markedly reduced MET expression at both the mRNA and protein levels. Knockdown of MET suppressed NPC cell proliferation, migration and invasion, whereas the restoration of MET rescued the suppressive effects of miR-34c. The demethylation agent 5-aza-2'-deoxycytidine (DAC) restored the expression of miR-34c in NPC cell lines. The promoter region of miR-34c was hypermethylated in NPC cells. In conclusion, miR-34c suppresses tumor growth and metastasis in NPC by targeting MET. The newly identified miR-34c/MET pathway provides further insights into the development and progression of NPC, and may represent a novel therapeutic target for NPC treatment.

Progesterone-induced cyclin G1 inhibits the proliferation of endometrial epithelial cell and its possible molecular mechanism.

Under normal conditions, progesterone inhi-bits the estrogen-induced proliferation of endometrial epithelium. Our previous studies have shown that cyclin G1 was progesterone-dependent in mouse endometrial epithelium at peri-implantation, and exogenous cyclin G1 suppressed the proliferation of endometrial cancer cells. The objectives of this study are to determine whether cyclin G1, as a negative regulator of the cell cycle, is involved in the antiproliferative action of progesterone on endometrial epithelial cells, and to explore the possible molecular mechanism of cyclin G1 inhibition. The siRNA-mediated elimination of cyclin G1 attenuated the antiproliferative action of progesterone on endometrial epithelial cells. Immunoprecipitation showed that progesterone-induced cyclin G1 could interact with PP2A to mediate its phosphatase activity. The block of PP2A activity also attenuated the antiproliferative action of progesterone on endometrial epithelial cells and increased the phosphorylated Rb. In conclusion, progesterone-induced cyclin G1 mediates the inhibitory effect of progesterone on endometrial epithelial cell proliferation possibly through the recruitment of PP2A to dephosphorylate Rb.

An experimental technique of split Hopkinson pressure bar using fiber micro-displacement interferometer system for any reflector.

A novel non-contact measurement technique had been developed for the mechanical properties of materials in Split Hopkinson Pressure Bars (SHPB). Instead of the traditional strain gages mounted on the surfaces of bars, two shutters were mounted on the end of bars to directly measure interfacial velocity using Fiber Micro-Displacement Interferometer System for Any Reflector. Using the new technique, the integrated stress-strain responses could be determined. The experimental technique was validated by SHPB test simulation. The technique had been used to investigate the dynamic response of a brittle explosive material. The results showed that the new experimental technique could be applied to the dynamic behavior in SHPB test.

[Clinical study on early use of Chinese medicinal herbs and chemotherapy after operation of gastric cancer].

In order to study the efficacy of early chemotherapy after operation of gastric cancer, 84 cases of gastric cancer were divided randomly into two groups. The treated group received both Chinese medicinal herbs and chemotherapy on the first postoperational day and the control group were treated routinely in the same way two weeks later. The results showed that complications of incision and anastomoses of the treated group did not rise and all kinds of blood cells reduce in comparison with those of control group (P > 0.05). Meanwhile, nutritious condition of the treated group was improved significantly as compared with that of control group (P < 0.05) because of use of Chinese medicinal herbs and nutrition support. This study suggested that chemotherapy could be used early after operation of gastric cancer in combination with Chinese medicinal herbs.

Single DNA marker generated by "YAC-Alu PCR" that is end-specific.

A simple strategy for the rapid preparation of an end-specific linking-DNA probe from the YAC-human chromosome 21 DNA recombinant clone and the characterization of this single DNA probe are described. Synthetic oligodeoxynucleotide primers, based on the consensus Alu sequence, and the Sup4 DNA fragment in the YAC arms were used to amplify end-specific DNA sequences by the polymerase chain reaction (PCR) for screening of the linking YAC recombinant clones ("YAC-Alu PCR"). Nucleotide sequencing of the product of PCR from human genomic DNA in a YAC insert confirmed the boundary between the vector and the insert and the presence of the 3'-end Alu-like structure. The probe R1, prepared by "YAC-Alu PCR" amplification, was assigned to chromosome 21 by Southern hybridization of somatic cell hybrid DNAs. In situ hybridization allowed localization of the R1 DNA probe to the human chromosome 21q21-q22.1 region. Thus, this approach has significant advantages not only for isolation of a single DNA probe specific for human chromosome 21 but also for the screening of YAC linking recombinant clones for mapping of the human genome.