The Role of Signal Transducer and Activator of Transcription 3 in Bone Homeostasis and Load-Driven Bone Remodeling / 医用生物力学

Bone homeostasis is a relative balance between bone formation and resorption. Signal transducer and activator of transcription 3 (STAT3), which is closely related to bone homeostasis, takes part in multiple intracellular and extracellular signal pathways. STAT3 participates in the process of osteoblast differentiation regulated by several factors. It can also maintain bone homeostasis by regulating the recruitment, differentiation and activation of osteoclasts. In addition, STAT3 is involved in the interaction between osteoblasts and osteoclasts. Patients with STAT3 mutations can have several inherited bone metabolism diseases. Furthermore, STAT3 plays a critical role in load-driven bone remodeling. Mechanical stimulation promotes osteoblast differentiation and bone formation through activating or enhancing STAT3 expression during bone remodeling process. This review summarizes the participation of STAT3 in maintaining bone homeostasis together with its possible mechanisms and discusses the connection between STAT3 and mechanical stimulation in bone remodeling, so as to provide a potential pharmacological target for the treatment of bone diseases.

Characterization of metabolic kinetics and CYP phenotyping of aloe emodin in liver microsomes / 国际药学研究杂志

Objective To characterize the metabolic kinetics of aloe emodin in human liver microsomes(HLM)and rat liver microsomes(RLM)and identify the CYP phenotyping of phaseⅠmetabolism. Methods Aloe emodin was incubated at 37℃ with HLM and RLM in the presence or absence of NADPH,UDGPA or NADPH+UDGPA. The remaining aloe emodin was determined with a validated LC-MS/MS method to assess the metabolic stability and enzymatic kinetics. A panel of rCYP isoforms(CYP1A2,2B6,2C8, 2C9,2C19,2D6 and 3A4)and HLM with specific inhibitors of CYP isoforms were used to identify the CYP phenotyping of aloe emo?din. Results In HLM and RLM,aloe emodin was metabolically eliminated in the presence of NADPH,with 85.8%and 81.7%of the parent compounds eliminated in 30 min,respectively. The t1/2 were(10.3±0.3)and(11.5±3.3)min,and the CLint were(420.1±10.9) and(573.4±188.2)ml/(min·kg),respectively. The apparent Km and Vmax for HLM and RLM were obtained and found to be(2.4±0.9) and(3.9±1.4)μmol/L,(1492±170.5)and(2783±595.8)nmol/(min·g protein),respectively. In RLM with UDPGA,38.5%of aloe emodin was metabolized in 30 min with t1/2 of 31.6 min and CLint of(197.1±15.5)ml/(min·kg). The results of CYP phenotyping indi?cated that CYP1A2,2B6,2C19 and 3A4 were the major enzymes involved in the metabolism of aloe emodin. By using the method of total normalized rate,the contributions of the major enzymes were assessed to be 35.4%,6.6%,2.2%and 21.9%,respectively. Con?clusion Aloe emodin is mainly eliminated by CYP mediated metabolism in HLM and RLM. CYP1A2 and 3A4 are the major responsi?ble enzymes of aloe emodin,and the contributions are above 20%. Species differences in liver metabolism of aloe emodin are observed. It undergoes notable glucuronidation in RLM only.

Expression of full-length spleen tyrosine kinase in the oral squamous cell carcinoma and its relationship with tumor invasion and metastasis / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression of full-length spleen tyrosine kinase [SYK (L)] mRNA and protein in human oral squamous cell carcinoma (OSCC) as well as its possible effects on the invasion and metastasis of OSCC.</p><p><b>METHODS</b>The expression of SYK (L) was detected in 27 cases of OSCC tissues and its matched adjacent non-cancerous tissues by real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, and immunohistochemistry. Fourteen cases of normal oral gingival tissues were also analyzed as a normal control.</p><p><b>RESULTS</b>Reduced mRNA and protein expression of SYK (L) in OSCC tissues was observed compared with that in normal oral gingival tissues (P<0.01) and adjacent non-cancerous tissues (P<0.05). SYK(L) expression was significantly associated with lymph-node metastasis (P<0.05).</p><p><b>CONCLUSION</b>SYK(L) is a candidate tumor suppressor for OSCC tissues, and has an inhibitive effect on the initiation, proliferation, and lymph-node metastasis of human OSCC.</p>

Construction of the siRNA expression vector and the silencing influence on focal adhesion kinase gene of Tca8113 cell line / 实用口腔医学杂志

Objective:To construct the siRNA expression vector of focal adhesion kinase(FAK) gene and inhibit the expression of FAK gene in tongue cancer cell line Tca8113 by RNA interfering technique. Methods:According to the encoding sequence of FAK mRNA, two pieces of oligonucleotide sequences were designed and synthesized. The annealed oligonucleotide fragments were subcloned into pGCSilencerTM-U6/Neo siRNA expression vector. After being identified by restriction enzyme method, the recombinant pSilencer-FAK plasmids were transfected into Tca8113 cells. The transfected cells were selected by G418 method. Immuocytochemistry and Western blotting were used to evaluate FAK gene silencing efficiency. Results:The oligonucleotide fragments were correctly inserted into pGCSilencerTM-U6/Neo vector. FAK expression of the transfected cells was significantly down-regulated by pSilencer-FAK. Conclusion:The siRNA expression vector of FAK is successfully constructed and FAK expression of Tca8113 cells can be inhibited by RNA interfering technique.