Microgravity is a typical feature of the space. A large number of space flights and foundation simulation experiments have shown that cells show typical biological characteristics of aging, such as reduced cell proliferation and cell cycle arrest under microgravity or simulated microgravity. However, the molecular mechanism by which microgravity or simulated microgravity affects cellular senescence is not well understood. Understanding the mechanism controlling cellular senescence induced by microgravity environment is helpful for exploring anti-aging strategies and targeted interventions in space. In recent years, domestic and foreign scholars have carried out a number of researches and explorations on the effect of microgravity and simulated microgravity on cellular senescence as well as the related mechanisms. In this review, the latest research progress of this filed was summarized.

Mesenchymal stem cells (MSCs) are pluripotent stem cells with high self-proliferation and multidirectional differentiation potential. They also have other functions including immune regulation, paracrine and so on, playing an important role in repairing injured tissues. In recent years, a lot of research has been done on how MSCs promote skin injury repair, and a lot of progress has been made. Compared with direct injection of MSCs in the wound area, some special treatments or transplantation methods could enhance the ability of MSCs to repair skin injury. This paper mainly discusses the role of MSCs in skin injury repair and technical ways to improve its repairing capacity, and discusses the existing problems in this field and prospects for future research directions.
Cell Differentiation ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stem Cells ; Skin

In the process of tumor growth, with the proliferation and expansion of cancer cells, the reconstruction of extracellular matrix (ECM) of cancer tissues, the restriction of surrounding tissues and the flow of cancer tissue interstitial fluid, the special stress environment is formed in the tumor tissues. Significant differences are found in the mechanical environment and mechanical characteristics of different regions of tumor tissues, that is, mechanical heterogeneity. The reseach shows that the mechanical properties of tumor tissue invasion frontier areas are more significant and complex. In particular, the epithelial-mesenchymal transition (EMT) of tumor cells also prefers to concentrate on this area. The mechanical stress generated by the invasion front can induce EMT of tumor cells through TWIST1, TGF-β, WNT and other force signal transduction pathways, and promote tumor cell invasion. From the perspective of tumor biomechanics, this review focuses on the relationship between mechanical heterogeneity of tumor cells and EMT, so as to provide the theoretical basis for mechanoenvironment-targeted therapy of tumors.

Objective To investigate the influences of different matrix stiffness on proliferation ability and glucose metabolism of hepatocellular carcinoma (HCC) cells and to explore the correlation between metabolism and biological behavior changes of HCC cells resulted from the stiffness of extracellular matrix (ECM)．Methods The proliferation changes of HepG2 cells cultured on matrix with different stiffness were detected by CCK-8 assay and cell count assay. 2-NBDG and flow cytometry were used to detect the effect of matrix stiffness on glucose uptake. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression level of Glut1. Then, 2-DG was used to inhibit glycolysis, and the influences of matrix stiffness on proliferation of HepG2 cells were detected. Results The proliferation ability, glucose uptake and the expression of Glut1 of HepG2 cells increased with the matrix stiffness increasing. When glycolysis was inhibited, the proliferation ability of HepG2 cells grown on matrix with different stiffness was similar. Conclusions The mechanical microenvironment had an important effect on proliferation of HCC cells; matrix with a larger stiffness might promote proliferation of HCC cells through regulating glycolysis. The research findings provide a corresponding experimental basis for the clinical treatment of HCC cells and drug development targeting glucose metabolism.

Tumor cells have unique energy metabolism phenomena, namely high glucose absorption, aerobic glycolysis and high lactic acid production, which are characterized by down-regulation of related proteins involved in oxidative metabolism in tumor cells, and up-regulation of glucose transporters and monocarboxylate transporters. Studies have shown that drugs that target tumor cell glucose metabolism have the ability to selectively kill tumor cells, bringing new hope for tumor treatment. Tumor stem cells are considered to be the root cause of tumor recurrence, metastasis and poor prognosis, and their energy metabolism characteristics have not yet been agreed. Studies have shown that reversing the energy metabolism of tumor stem cells can increase their chemosensitivity. This article reviews recent studies on tumor and tumor stem cell glucose metabolism and the opportunities and challenges of tumor treatment through targeting glucose metabolism, which might provide new ideas and opportunities for clinical tumor therapy.
Energy Metabolism ; Glucose ; metabolism ; Glycolysis ; Humans ; Lactic Acid ; metabolism ; Neoplasms ; metabolism ; Neoplastic Stem Cells ; metabolism

Objective To study the effects of osteopontin (OPN) on the nuclear mechanics of bone marrow-derived mesenchymal stem cells (BMSCs) as well as its involved mechanisms. Methods The BMSC migration was evaluated using the Transwell assay. An atomic force microscope (AFM) was used to determine the elastic modulus of the BMSC nucleus and analyze the changes in the nuclear mechanics of the BMSCs after treatment with OPN. The activation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase1/2 (ERK1/2) was measured by Western blot. The role of the FAK-ERK1/2 signaling pathway in mediating the OPN-affected BMSC nuclear mechanics was investigated by employing a specific inhibitor. RT-PCR and Western blot were used to detect the expression of Lamin A/C at mRNA and protein levels in the BMSCs, respectively. Results The elastic modulus of the BMSC nucleus exhibited a significant decrease after OPN treatment compared with that of the control group. OPN could upregulate the phosphorylation level of FAK and ERK1/2, but the inhibitor of FAK or ERK1/2 restored the OPN-decreased elastic modulus of the BMSC nucleus and inhibited the BMSC migration significantly. After treatment with OPN, the expression of Lamin A/C in the BMSCs reduced significantly, and such a reduced expression could be suppressed by the inhibitor of FAK or ERK1/2. Conclusions OPN could probably downregulate the expression of Lamin A/C of the BMSCs via the FAK-ERK1/2 signaling pathway, decrease the stiffness of the BMSC nucleus, and promote the migration of the BMSCs. The research outcomes provide the experimental evidence for further understanding the mechanism of the OPN-regulated BMSC migration and its potential clinical application.

BACKGROUND:Cel cryopreservation is required for clinical use of stem cel s, and the current process of cryopreservation however may be harmful to cel viability, pluripotency and differentiation capacity.
OBJECTIVE:To explore the effect of fructose and dithiothreitol on pluripotency and osteogenesis of cryopreserved bone marrow mesenchymal stem cel s.
METHODS:Bone marrow mesenchymal stem cel s were isolated from the bone marrow of Sprague-Dawley rats and pretreated with fructose (200μmol/L), dithiothreitol (500μmol/L) or combined components before cryopreservation. Then the cel s were cryopreseved for 6 months and the morphology of cel s was observed by inverted microscopy. The cel viability was evaluated by MTT, and real-time PCR was used to detect the mRNA expression of Nanog, OCT4 and Sox2. Alkaline phophatase activity assay and alizarin red staining were utilized to detect the osteogenic capacity of bone marrow mesenchymal stem cel s.
RESULTS AND CONCLUSION:Images captured by inverted microscopy showed no significant difference in cel morphology between groups. The MTT results indicated that fructose and combined pretreatment could promote the cel viability of bone marrow mesenchymal stem cel s after cryopreservation, while the real-time PCR results demonstrated that dithiothreitol significantly facilitated the expression of Naogo and Sox2 in bone marrow mesenchymal stem cel s. Moreover, ALP activity assay and alizarin red staining confirmed the positive effects of fructose, dithiothreitol and combined pretreatment on osteogenic capacity of bone marrow mesenchymal stem cel s after cryopreservation, and the best effects were found after pretreatment with dithiothreitol and combined components. Overal , these findings indicate that fructose pretreatment is beneficial for cel viability of cryopreseved bone marrow mesenchymal stem cel s, and dithiothreitol contributes to maintaining the pluripotency and osteogenesis capacity of cryopreseved bone marrow mesenchymal stem cel s.

In this study, we aimed to investigate the influences of conditioned medium from human umbilical vein endothelial cells (HUVEC) on cancer stem cell phenotype of human hepatoma cells. HUVEC and human hepatoma cells (MHCC97H) were cultured, respectively, and then the MHCC97H cells were co-cultured with conditioned medium from HUVEC (EC-CM) with Transwell system. Anti-cancer drug sensitivity, colony-formation, migration/invasion ability, expression of cancer stem cell marker and sphere formation were performed to determine the cancer stem cell phenotype in MHCC97H cells. We found that MHCC97H cells co-cultured with EC-CM exhibited significantly higher colony-formation ability and lower sensitivity of anti-cancer drugs 5-FU and Cis. Transwell assay showed that treatment with EC-CM obviously increased migration and invasion of MHCC97H cells. Moreover, increased sphere forming capability and expression of CD133 in MHCC97H cells were observed after co-cultured with EC-CM. These results suggested that EC-CM could promote cancer stem cell phenotype of hepatoma cells.
Antineoplastic Agents ; pharmacology ; Carcinoma, Hepatocellular ; Cell Line, Tumor ; Coculture Techniques ; Culture Media, Conditioned ; Fluorouracil ; pharmacology ; Human Umbilical Vein Endothelial Cells ; chemistry ; Humans ; Liver Neoplasms ; Neoplastic Stem Cells ; cytology ; Phenotype

Objective To investigate the effect of dexmedetomidine combined with butorphanol conventional therapy on sustaining sedation of intensive care unit (ICU) patients.Methods Sixty critically ill patients in Binzhou Central Hospital from June to September in 2014 were randomly divided into experimental group and control group, 30 cases in each group. In the control group, 0.8 mg/L dexmedetomidine hydrochloride injection (400μg with addition of 46 mL normal saline to form 50 mL solution) was intravenously infused continuously at a speed of 0.4μg·kg-1·h-1 by a micro-pump to induce analgesia and sedation; while in the experimental group, dexmedetomidine combined with 200 mg/L butorphanol (10 mg plus 40 mL normal saline to form 50 mL solution) was given for intravenous infusion by a micro-pump with a speed of 0.01 mg·kg-1·h-1 to maintain analgesia and sedation for 48 hours whose required Ramsay score in both groups was 3 - 5. Before and after treatment, the changes of heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP), arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), and the pulse oxygen saturation (SpO2) of both groups were observed. The dosage of dexmedetomidine used for maintenance of required analgesia and sedation and FPS (facial expression) grading and Ramsay score were compared respectively between the two groups, and the clinical efficacy of the two groups were evaluated.Results After treatment, the HR, MAP, RR in both groups were significantly lower, and PaO2 and SpO2 were significantly higher than those before treatment, and the degrees of improvement in the above indexes of the experiment group were superior to those of the control group [HR (bpm): 84.58±12.43 vs. 118.62±14.21, MAP (mmHg, 1 mmHg = 0.133 kPa): 82.35±12.12 vs. 92.35±12.32, RR (times/min): 25.42±3.98 vs. 32.87±5.12, PaO2 (mmHg): 95.21±10.55 vs. 75.18±8.57, SpO2: 0.981 4±0.102 8 vs. 0.954 7±0.093 8, allP < 0.05]. The total therapeutic effect in experiment group was significantly higher than that in control group [93.3% (28/30) vs. 76.7% (22/30),P < 0.05]. The dexmedetomidine dosage used in the experiment group was much less than that in the control group (μg/d: 412.12±23.18 vs. 520.05±15.68,P < 0.05). The FPS score in the experiment group was obviously lower than that in the control group (1.48±0.16 vs. 2.52±0.74,P < 0.05).Conclusion In comparison, to achieve sustained and required analgesic and sedative effect for ICU patients by combined use of dexmedetomidine and butorphanol, the dosage of dexmedetomidine used is less than dexmedetomidine applied alone, in addition, the combined use can achieve better Ramsay grading, steady blood pressure and excellent effect.

Hepatocellular carcinoma (HCC) is one of the most common human malignant tumors worldwide; it is also hard to prevent its metastasis and recurrence by traditional treatments. Up to now, how to prevent and treat HCC is still a challenging problem in clinic. Cancer stem cells (CSCs) are cells within malignant tumor that possess the capacity to self-renew and differentiate to lead to the heterogeneous lineages of cancer cells that comprise the tumor, and are the root to cause metastasis, recurrence and bad prognosis of the cancer. Targeting CSCs is a novel therapeutic strategy for management and treatment of the cancer. In recent years, targeting intervention on liver cancer stem cells (LCSCs) gradually became a novel strategy for HCC treatment, and some exciting research results in the treatment of HCC were also achieved. In this review, we introduce the biological characteristics of LCSCs and highlight the therapeutic strategies for hepatocellular carcinoma by targeting intervention on LCSCs.
Animals ; Antineoplastic Agents ; therapeutic use ; Carcinoma, Hepatocellular ; therapy ; Humans ; Liver Neoplasms ; therapy ; Molecular Targeted Therapy ; Neoplastic Stem Cells ; metabolism ; pathology