【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.
ObjectiveTo summarize the therapeutic targets of pancreatic cancer (PC). MethodsThe related literatures about the therapeutic targets of PC were reviewed. ResultsPC was one of the most challenging tumor in worldwide, and was characterized as a highly aggressive disease with poor overall prognosis and a high mortality rate. The hallmark of PC was its poor response to radio-and chemo-therapy. Current chemotherapeutic regimens could not provide substantial survival benefit with a clear increase in overall survival. Recently, several new approaches which could significantly improve the clinical outcome of PC had been described, involving signal-transduction pathways, immune response, stroma reaction, and epigenetic changes. ConclusionsMany therapeutic targets are involved in the treatment of PC. As current therapies failed to significantly improve the progression and the survival of PC, new therapeutic approaches and clinical studies are strongly required.
Objective To investigate the activation and role of signal transduction pathway of epidermal growth factor (EGF)-epidermal growth factor receptor (EGFR)-mitogen activated protein kinase (MAPK) in proliferation of human retinal pigment epithelial (RPE) cells. Methods Human RPE cells were stimulated with 0.1%，10% foetal calfserum (FCS) and EGF(0.1, 1, 10, 50 and 100 ng/ml)in 0.1% FCS Dulbeco′s modified Eagle′s medium (DMEM) and in 10% FCS DMEM for 3 days, respectively. Immunohistochemical staining and in situ hybridization were used to observe the expressions of EGFR protein and EGFR mRNA，respectively. Activation of MAPK was detected by immunohistochemical method with specific anti-phosphorylated ERK 1/2 antibody. Results The optimal concentrations of EGF were 10 ng/ml in 0.1% FCS DMEM and 1 ng/ml in 10% FCS DMEM. After 3 days of stimulation with EGF, phosphorylated ERK 1/2 staining was detectable in nucleus of RPE cells, whereas cells presented immunostaining for phosphorylated ERK 1/2 in the cytoplasm before stimulation. Conclusions EGF may improve the expression of EGFR protein and EGFR mRNA of RPE cells, and induced MAPK nuclear translocation in a concentration-dependent manner. EGF-EGFR-MAPK signal transduction pathway may play a key role in RPE cells proliferation, and serum exerts an important acceclerating function in the process. (Chin J Ocul Fundus Dis，2004，20：67-132)
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 summarize the role of Piezo mechanosensitive ion channels in the osteoarticular system, in order to provide reference for subsequent research. Methods Extensive literature review was conducted to summarize the structural characteristics, gating mechanisms, activators and blockers of Piezo ion channels, as well as their roles in the osteoarticular systems. Results The osteoarticular system is the main load-bearing and motor tissue of the body, and its ability to perceive and respond to mechanical stimuli is one of the guarantees for maintaining normal physiological functions of bones and joints. The occurrence and development of many osteoarticular diseases are closely related to abnormal mechanical loads. At present, research shows that Piezo mechanosensitive ion channels differentiate towards osteogenesis by responding to stretching stimuli and regulating cellular Ca2+ influx signals; and it affects the proliferation and migration of osteoblasts, maintaining bone homeostasis through cellular communication between osteoblasts-osteoclasts. Meanwhile, Piezo1 protein can indirectly participate in regulating the formation and activity of osteoclasts through its host cells, thereby regulating the process of bone remodeling. During mechanical stimulation, the Piezo1 ion channel maintains bone homeostasis by regulating the expressions of Akt and Wnt1 signaling pathways. The sensitivity of Piezo1/2 ion channels to high strain mechanical signals, as well as the increased sensitivity of Piezo1 ion channels to mechanical transduction mediated by Ca2+ influx and inflammatory signals in chondrocytes, is expected to become a new entry point for targeted prevention and treatment of osteoarthritis. But the specific way mechanical stimuli regulate the physiological/pathological processes of bones and joints still needs to be clarified. Conclusion Piezo mechanosensitive ion channels give the osteoarticular system with important abilities to perceive and respond to mechanical stress, playing a crucial mechanical sensing role in its cellular fate, bone development, and maintenance of bone and cartilage homeostasis.
Objective To compare the effect of mosaicplasty, mosaicplasty with gene enhanced tissue engineering and mosaicplasty with the gels of non-gene transduced BMSCs in alginate on the treatment of acute osteochondral defects. Methods Western blot test was conducted to detect the expression of hTGF-β1, Col II and Aggrecan in 3 groups, namely hTGF-β1 transduction group, Adv-βgal transduction group and blank control group without transduction. Eighteen 6-month-old Shanghai mascul ine goats weighing 22-25 kg were randomized into groups A, B and C (n=6). BMSCs were isolatedfrom the autologous bone marrow of groups B and C, and were subcultured to get the cells at passage 3. In group B, the BMSCs were transduced with hTGF-β1. For the animals of 3 groups, acute cyl indrical defects 5 mm in diameter and 3 mm in depth were created in the weight bearing area of the medial femoral condyle of hind l imbs. In group A, the autologous osteochondral mosaicplasty was performed to repair the defect; in group B, besides the mosaicplasty, the dead space between the cyl indrical grafts and the host cartilage were injected with the suspension of hTGF-β1 gene transduced autogenous BMSCs in sodium alginate, and CaCl2 was dropped into it to form calcium alginate gels; in group C, the method was the same as the group B, but the BMSCs were not transduced. General condition of the goats after operation was observed, the goats were killed 12 and 24 weeks after operation to receive gross and histology observation, which was evaluated by the histological grading scale of O’Driscoll, Keeley and Salter. Immunohistochemistry and TEM observation were performed 24 weeks after operation. Results Western blot test showed the expression of the hTGF-β1, Col II and the Aggrecan in the hTGF-β1 transduction group were significantly higher than that of the Adv-βgal transduction and the blank control groups. All the goats survived until the end of experiment and all the wounds healed by first intention. Gross observation revealed the boundaries of the reparative tissue in group B were indistinct, with smooth and continuous surfaces of the whole repaired area; while there were gaps in the cartilage spaces of groups A and C. Histology observation showed the dead space between the cyl indrical grafts in group A had fibrocartilage-l ike repair tissue, fill ing of fibrous tissue or overgrowth of the adjacent cartilage; the chondrocytes in group B had regular arrangements, with favorable integrations; while the dead space between the cyl indrical grafts in group C had fibrocartilage-l ike repair tissue, with the existence of gaps. The histology scores of group B at different time points were significantly higher than that of groups A and C, and group C was better than group A (P lt; 0.05); for group B, significant difference was detected between 12 weeks and 24 weeks in the histology score (P lt; 0.05）. Immunohistochemistry staining for Col II 24 weeks after operation showed the chondrocytes and lacuna of the reparative tissue in group B was obviously stained, while groups A and C presented l ight staining. TEM observation showed there were typical chondrocytes in the reparative tissue in group B, while parallel or interlaced arrangement collagen fiber existed in groups A and C. Conclusion Combining mosaicplasty with tissue engineering methods can solve theproblem caused by single use of mosaicplasty, including the poor concrescence of the remnant defect and poor integration with host cartilages.
Stem cells are crucial for embryonic development and in the maintenance of adult cellular homeostasis. Understanding the regulatory network of stem cells, including embryonic and adult stem cells, will allow us to learn the pathogenesis and possibly design novel approaches to treat many diseases (such as cancer and degeneration). The retinoblastoma (Rb) pathway controls cellular proliferation, differentiation and death. More and more evidences support an important role of Rb activity in the biology of stem and progenitor cells. Transiently inactivating Rb pathway might favor the expanding of functional stem cell populations, thus have values in the future stem cell applications.
Objective To observe the characteristics of magnetic resonance diffusion tensor imaging（MR-DTI）for optic nerves and optic radiation in blind patients.Methods The optic nerves and optic radiation of 20 blind patients（blind group）and 20 controls（control group） were scanned by MR-DTI. Fractional anisotropy (FA) and directional encoded color (DEC) maps were acquired through postprocessing with the aid of volumeone 1.72 software. The signal intensity of optic nerves and optic radiation were then observed. The FA, mean diffusivity (MD), lambda;∥ and lambda;perp; value of bilateral optic nerves and optic radiation in two groups were measured in the DEC maps.Results While the high signal intensity was found in bilateral optic nerves in FA and DEC maps in control group，the signal decreased markedly in the blind group. The FA and lambda;∥ value of optic nerves in the blind group were declined obviously compared to that in the control group. The difference was statistically significant (t=16.294, 14.660;P=0.000). The MD and lambda;perp; value of optic nerves in the blind group were increased obviously compared to that in the control group, the difference was also statistically significant (t=8.096, 8.538; P=0.000). The high signal intensity was found in bilateral optic radiation in FA and DEC maps in both the blind and control groups. There were no statistic differences in FA and MD value in bilateral optic radiation between the blind and control groups (Left：t=1.456，1.811；P=0.152，0.076. Right：t=0.779，0.073；P=0.440，0.942). Conclusion A low signal intensity of bilateral optic nerves and a high signal intensity of bilateral optic radiation were found in blind patients.
Continuous activation of Janus kinase (JAK)- signal transduction and activator of transcription (STAT) signaling pathway is prevalent in leukemia cells, and it has been found that this pathway plays an important role in acute leukemia (AL). JAK2/JAK1 gene mutations are found in both acute myelocytic leukemia and acute lymphoblastic leukemia and may have implications for the treatment and overall prognosis of the disease. Among the STAT family members, STAT3 and STAT5 proved to be key factors in AL. These gene mutations may provide new targets and new ideas for the treatment of AL. This article provides a review of the research progress of JAK-STAT signaling pathway, related gene mutations and AL.
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.