Mechanism of participation of osteocytes in the formation of osteoclasts under hypoxia / 华西口腔医学杂志

OBJECTIVE@#To investigate the mechanism of the participation of osteocytes in the formation of osteoclasts under hypoxia.@*METHODS@#The hypoxia culture system of osteocyte-like cell line MLO-Y4 was established by deferoxamine mesylate (DFO) in vitro. The proliferation of MLO-Y4 cells was examined by CCK-8 cell proliferation/toxicity assay. RAW264.7 cells were induced to osteoclasts by the conditioned medium containing the cultured MLO-Y4. Tartrate-resistant acid phosphatase (TRAP) staining was performed on day 7. Quantitative real-time fluorescence polymerase chain reaction, immunofluorescence, and Western blot were used to detect the expression levels of hypoxia-inducible factor (HIF)-1α and receptor activator of nuclear factor-κB ligand (RANKL) in MLO-Y4 under hypoxia. The effects of siHIF-1α on the expression levels of HIF-1α and RANKL in MLO-Y4 under the same conditions were detected.@*RESULTS@#DFO (100 μmol·L⁻¹) promoted the proliferation of MLO-Y4 at 24 h, which decreased with time (P<0.01). After the addition of soluble sRANKL, the formation of osteoclasts was significantly increased in the DFO group (P<0.001). The expression of RANKL mRNA in MLO-Y4 under 100 μmol·L⁻¹ DFO increased first and then decreased with the duration of hypoxia. This expression reached a peak at 24 h (P<0.01). Hypoxia up-regulated the expression of HIF-1α and RANKL protein (P<0.01). Under hypoxia, siHIF-1α downregulated the expression of HIF-1α and RANKL (P<0.01). siHIF-1α also decreased the number of osteoclasts (P<0.01).@*CONCLUSIONS@#Under hypoxia, MLO-Y4 could facilitate the formation of RANKL through upre-gulating the expression of HIF-1α protein, thereby accelerate the differentiation of RAW264.7 cells into osteoclasts.

Biological characteristics of CD133+ subpopulation in tongue squamous cell carcinoma Tca8113 cell line / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To detect the expression of CD133 in human tongue squamous cell carcinoma Tea8113 cell line and observe proliferation ability of CD133 groups in vitro.</p><p><b>METHODS</b>Limiting dilution assay was employed to observe the proliferating character of Tca8113 single cell in vitro. The ability of growing as cancer spheroids was observed with ultra-low attachment plates. The flow cytometry was used to detect the expression of putative tumor-initiating cell marker CD133 in human tongue squamous cell carcinoma Tca8113 cell line. The selective technique of immunomagnetic beads was applied to purify CD133 tumor cells, CD133 tumor cells were cultured and their ability of proliferation were observed in vitro.</p><p><b>RESULTS</b>After 12 days, the result of single cell culture in vitro revealed that about 5.23% of cultured Tca8113 cells possessed the capacity of continue proliferation. The cells line fromed floating clusters with one week of passaging cells into non-adherent plates. Approximately 0.95% of cells in Tca8113 cell line expressed CD133. Compared with CD133- cells and control Tca8113 cells, CD133+ cells demonstrated increased proliferation capacity. The proportion of CD133 cells decreased in culture as days passed. The percentage of CD133+ cells decreased from 92.45% to 1.62% in twelve days' culture.</p><p><b>CONCLUSION</b>Tumor stem cells have the character of heterogenity and lower proportion of CD133 but higher ability of proliferation, and the diferentiation in human tongue squamous cell carcinoma Tca8113 cell line in vitro, CD133 may be one of makers for tumor-initiating cell of human tongue squamous cell carcinoma Tca8113 cell line.</p>

Proteomics study of the serum biomarkers in tongue cancer / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To search for specific serum biomarkers associated with tongue cancer by means of the serum proteomics technology.</p><p><b>METHODS</b>The tongue cancer cells of human tongue cancer cell line Tca8113 were subcutaneously inoculated into nude mice, while control nude mice were injected with phosphate-buffered saline. Serums from these two group of mice were collected for proteomic analysis using two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS).</p><p><b>RESULTS</b>Comparing the serum 2-DE maps from the tumor-bearing mice with those produced from control mice, we found that squamous cell carcinoma antigen 1 was over expressed only in the serum of tumor-bearing mice.</p><p><b>CONCLUSIONS</b>The squamous cell carcinoma antigen 1 may be of great potential as the biomarker of tongue cancer and as the potential therapeutic target for gene therapy.</p>

Experimental studies on ectopic osteogenesis by seeding human mesenchymal stem cell on human natural bone derived scaffold materials / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the ectopic osteogenesis potential of human natural bone derived material combined with human bone marrow mesenchymal stem cells (MSCs).</p><p><b>METHODS</b>Cell-scaffold complexes were implanted subcutaneously into the left back of the nude mice, and human natural bone derived material were implanted into the right back as control group. The mice were killed respectively on the postoperative 2 weeks, 4 weeks and 8 weeks. The macroscopic, histopathological, alkaline phosphatase (ALP) activity assay methods were performed to assess the ectopic osteogenesis potential.</p><p><b>RESULTS</b>The cartilaginous osteogenesis were observed in both deproteinated bone and decalcified bone, and the more new bone tissue formed gradually as the time went by after implantation. ALP activity become stronger followed with the time (P < 0.05), and compared with the decalcified bone, deproteinated bone displayed stronger ALP activity (P < 0.05).</p><p><b>CONCLUSION</b>The MSCs and human natural bone derived material can be used as good seed cells and scaffold materials respectively to construct tissue-engineered bone, and as the scaffold material, deproteinated bone has better osteogenesis ability than decalcifed bone.</p>