【Abstract】Objective To investigate the apoptosis induced by TGF-β1 in human hepatic carcinoma cell lines and its relationship with p53 gene and Smad. Methods Three human hepatic carcinoma cell lines which involving in various status of the p53 gene were used in this study. TGF-β1-induced apoptosis in hepatic carcinoma cell lines was measured by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. To study the mechanism of TGF-β1-induced apoptosis, these cell lines were transfected with a TGF-β1-inducible luciferase reporter plasmid containing Smad 4 binding elements (SBE) and luciferase gene using Lipofectamine 2000, then treated with TGF-β1, relative luciferase activity was assayed. Results Of three cell lines studied with TUNEL assay, TGF-β1 induced apoptosis was observed in HepG2 cells (wild type p53). Huh-7 (mutant p53) and Hep3B (deleted p53) cell lines showed less apoptosis. Luciferase activity assay indicated that the response to TGF-β1 induction in HepG2 cells was increased dramatically but was not significant in Huh-7 and Hep3B cell lines. Conclusion HepG2 cells seem to be highly susceptible to TGF-β1-induced apoptosis compared with Hep3B and Huh7 cell lines. Smad 4 is a central mediator of the TGF-β1 signal transduction pathway.
Objective To probe into the roles of inositol 1, 4, 5-trisphosphate (IP3) and bcl-2 gene expression in inhabiting hepatocellular carcinoma of nude mice by quercetin. Methods Animals with hepatocellular carcinoma in quercetin group were treated with injection peritoneum of quercetin 50 mg/（kg·d ） for 3 weeks, while which in control group were treated with 0.4% DMSO of RPMI 1640 0.05 ml/（g·d）. Then the volume and the weight of tumors were measured, IP3, bcl-2 mRNA and bcl-2 protein were assayed by IP3-［3H］ Birtrak Assay, RT-PCR and Western blot respectively. Results The volume and weight of tumors in quercetin group were lower than those in control group 〔（15.8±10.1） mm3 vs. （52.3±26.5） mm3 in volume, （44.8±10.4） mg vs.（91.3±31.4） mg in weight， P＜0.01〕. Content of IP3 in quercetin group was lower than that in control group 〔（13.4±1.4） pmol/mg prot vs. （35.3±6.6） pmol/mg prot， P＜0.01〕. There was no significant difference in bcl-2 mRNA expression between quercetin group and control group 〔RI （the gray degree multiply area of bcl-2 /the gray degree multiply area of β-actin）： 0.55±0.05 vs. 0.79±0.19， P＞0.05〕， but the expression of bcl-2 protein in quercetin group was lower than that in control group (RI: 1.07±0.12 vs. 6.69±1.80, P＜0.01). Conclusion Quercetin can inhabit the growth of hepatocellular carcinoma tansplanted into liver of nude mice by reducing IP3 production and down-regulating bcl-2 gene expression.
Mechanical stress modulates almost all functions of cells. The key to exploring its biological effects lies in studying the perception of mechanical stress and its mechanism of mechanotransduction. This article details the perception and mechanotransduction mechanism of mechanical stress by extracellular matrix, cell membrane, cytoskeleton and nucleus. There are two main pathways for the perception and mechanotransduction of mechanical stress by cells, one is the direct transmission of force, and the other is the conversion of mechanical signal into chemical signal. The purpose of this study is to provide some reference for the exploration of precise treatment of mechanical stress-related diseases and the optimization of construction of tissue engineered organs by mechanical stress.
Rheumatoid arthritis (RA) is a chronic autoimmune disease remarkably characterized by synovitis of joints, whose pathogenesis is complicated and not yet fully elucidated. A variety of cells, cytokines and intercellular signaling pathways are involved in the occurrence and development of RA. The mitogen activation protein kinase (MAPK) signaling pathway is closely related to the pathogenesis of RA, and plays an important role in the formation of pannus, synovitis, and bone destruction. This paper reviews the research progress of MAPK signaling pathway in RA from the aspects of the interaction of MAPK signaling pathway with a variety of key cells and cytokines in the pathogenesis of RA, in order to provide a direction and theoretical basis for anti-RA drug therapy research.
ObjectiveTo investigate the effect of icaritin on the small cell lung cancer cell lines NCI-H446 and its mechanism. MethodsThe NCI-H446 cells at logarithmic growth phase were divided into control and icaritin groups. The cells in the control group were normally treated and cells in the icaritin group were incubated with icaritin (8 μmol/L). Thiazole blue and flow cytometry were used to examine the proliferation and apoptotic changes in the two groups 48 hours after incubation respectively. Gene expression of Janus kinase 2 (JAK2) and signal transducers and activators of transcription 3 (STAT3) were detected by real-time quantitative polymerase chain reaction. The changes of JAK2, STAT3, phospho-JAK2 (p-JAK2), phospho-STAT3 (p-STAT3), Bax and BCL-2 protein were detected by Western blotting. ResultsCompared with the control group, the proliferation rate of NCI-H446 cells in the icaritin group was significantly lower (P<0.05), but the apoptotic rate of NCI-H446 cells in the icaritin group was significantly higher (P<0.05). After the treatment with icaritin, the expression of JAK2 and STAT3 mRNA had no obvious differences. The Western blotting results showed that there was no significant changes in total JAK2, STAT3 protein (P>0.05), but an increasing trend in p-JAK2, p-STAT3 and Bax was observed with the decreasing of BCL-2 (P<0.05). ConclusionIcaritin can inhibit the proliferation and promote the apoptosis of NCI-H446 cells and the effect may be achieved through JAK2/STAT3 signal transduction pathway.
ObjectiveTo investigate the expressions of Patched-1 (Ptch1) and glioma-associated oncogene homologl (Gli1) protein of sonic hedgehog signaling pathway in cholangiocarcinoma tissues, and explore their correlations to the occurrence and development of cholangiocarcinoma. MethodsThe expressions of Ptch1 and Gli1 protein in 62 specimens of cholangiocarcinoma and its bile duct tissues adjacent to cancer were detected by immunohistochemistry, and their positive rate correlated with patients, age, tumor size, differentiation grade, tumor location, lymph node metastasis, TNM stage, operation mode, and postoperative survival time were investigated by statistical analysis. ResultsThe positive rates of Ptch1 and Gli1 protein were significantly higher in cholangiocarcinoma than in tissues adjacent to cancer (74.2% vs. 14.5%, 88.7% vs. 9.7%, P < 0.05). The expressions of Ptch1 and Gli1 protein in cholangiocarcinoma had no correlation to patients age, tumor size, and tumor location (P > 0.05), but were correlated to the operation mode, differentiation grade, lymph node metastasis, TNM stage, and postoperative survival time of patients (P < 0.05). ConclusionsThe elevated expressions of Ptch1 and Gli1 protein of Hh signaling pathway participated in the occurrence and development of cholangiocarcinoma. They may be ideal targets for therapy against cholangiocarcinoma.
Objective To study the leptin-mediated intracellular signal pathways and their effects on wound healing.Methods The literature was reviewed extensively, concerning the physical and chemical characters of leptin, the mechanism of its receptor action, the receptor-related intracellular signal pathways and their roles on wound healing. Results Leptin was a protein hormone expressed by ob gene with relative molecular mass 16×103, it could activate the main singal pathways such as Janus kinase/signal transducer and activator of transcription, mitogenactivated protein kinases and phosphoinositide-3-kinase pathways through binding with its specific receptor, to participate in the modulation of multiple functions including energy metabolism, weight balance and wound healing. Leptin receptors were widely distributed in various tissues, which suggest the multiple functions of leptin. Local leptin expression was increased after skin injured, and it could stimulate keratinocytes proliferation, epithelialization, fibroblast proliferation and collagen synthesis, resulting in accelarated wound repair. Leptin expression was significantly increased after mucosal injury or bacteria infections, leading to accelarated mucosal repair through modulation of mucosal glandular secretion, improvment of mucosal blood flow, and synergistic action with endothelin-1.Conclusion Leptin can promote wound healing through activating its receptor-related intracellular signal pathways.
ObjectiveTo investigate the expression of interleukin-18（IL-18）and signal transducers and activators of transcription 5（STAT5）in retina of 4-24-week-old diabetic rats, and explore the potential molecular mechanisms involved in diabetic retinopathy (DR).MethodsRetinal gene expression profile of healthy and 8-week-old diabetic rats was established with restriction fragment differential displaypolymerase chained reaction (RFDD-PCR), and the differences was analyzed by bioinformatics. IL-18 and STAT5 were filtrated as the candidate genes of DR. The expression of IL-18 and STAT5 in retina of diabetic rats with the age of 4, 8, and 24 weeks was observed by semi-quantitative reverse transcriptase-polymerase chain reaction（RT-PCR）.ResultsThe result of RFDD-PCR showed:expression of IL-18 was higher in healthy retina than that in diabetic one; expression of STAT5 was not found in healthy rats but in diabetic ones. The result of RT-PCR showed：compared with the normal, high expression of IL-18 was found in 4-week diabetic retina, reduced in 8-week one, and decreased to the lowest in 24-week one. The expression of STAT5 was not observed in healthy or 4week diabetic retina, but occurred in 8-week one, and increased in 24-week one. ConclusionThe expression of IL-18 and the activation of STAT5 may relate to the occurrance of DR. The expression of IL-18 doesn′t depend on the activation of STAT5. (Chin J Ocul Fundus Dis, 2005,21:258-260)
Objective To review the latest development of the research on the selfrenwal signaling pathway and culture system in vitro of the embryonic stem cells(ESCs). Methods The recent articlesabout the selfrenewal signaling pathway and culture system in vitro of the ESCs were extensively reviewed. Results Understanding of the molecular mechanism of the selfrenewalin vitro and pluripotency of the ESCs was considered important for developing improved methods of deriving, culturing and differentiating these cells into the cells that could be successfully used in the clinical practice. Conclusion A further research is needed to elucidate the selfrenewal signaling pathway and the pluripotency of the ESCs and the culture systemin vitro forthe human ESCs remains to be further improved and developed.