Response of cementoblast-like cells to mechanical tensile or compressive stress at physiological levels in vitro
To clarify the role of cementoblast in orthodontic-related root resorption, this study was attempted to examine whether murine cementoblast-like cells are responsive to mechanical stress, and how mechanical forces regulate bone sialoprotein (BSP) and osteopontin (OPN) gene expression in these cells in vitro. In this force-loading model, defined and reproducible mechanical loadings of different magnitudes and types were applied up to 24 h. Besides a transitory and reversible change in cell proliferation, remarkable alterations in gene transcription of BSP and OPN were found. BSP mRNA was suppressed by the stresses. Three and six hours-loadings at 2,000 microstrain up-regulated the expression of OPN mRNA, while the other loadings inhibited it. The study also concluded that 4,000 microstrain was likely to exert more influence on cementoblast-like cells than 2,000 microstrain. Furthermore, no obvious evidence indicated the difference between tension and compression. These results suggested that cementoblast-like cells are sensitive to mechanical stress, and may play a role in regulating orthodontic-related root resorption/repair.
- [Show abstract] [Hide abstract] ABSTRACT: Osteopontin (OPN) plays an important role in metastasis and relapse of human cancer. However, the whole story of OPN relating to cancer has been far from clear untill now. To investigate the expression of OPN in hepatocellular carcinoma (HCC) and its relationships with recurrence and metastasis of HCC, normal and malignant liver tissues from patients with HCC were analyzed using immunohistochemical staining. OPN expression was inhibited by small interfering RNA (siRNA) in HCC cells lines, and then colony formation and matrigel invasion were examined. The results showed that expression of OPN was associated with metastasis of HCC with a positive rate of OPN in the tissue of HCC (70.00%), which was highly more obvious than those in paracarcinoma tissue and normal liver tissue (P < 0.01). In HCC cell lines, OPN depletion could reduce formed colony and metastasizing numbers in vitro. In conclusion, Expression of OPN in the tissue of HCC is related to metastasis or metastases. Specific siRNA could decrease expressions of OPN at both mRNA and protein levels, and abates the invasiveness of hepatocellular carcinoma cells, suggesting that OPN might be a promising agent for treatment of metastasis and recurrence of HCC.0Comments 17Citations
- [Show abstract] [Hide abstract] ABSTRACT: Objective In recent years, great development has been made in cytomechanics in orthodontic tooth movement(OTM). The essential role of periodontal ligament in OTM has been widely accepted. The in vitro models have become an important way to reveal the biological mechanism in OTM, largely based on periodontal ligament cells(PDLCs), as well as other cells, including bone marrow mesenchymal stem cells, osteoblast, cementoblast and myoblast. The in vitro models have been renovated from the traditional ways stressing the 2D-cultured cells by deformation of the bottom, gravity, hydrostatic pressure or centrifugation, to the establishment of various novel models loading mechanical stimulation on cells 3D-cultured in bioscaffolds. The molecular expression involved in the osteoblastic differentiation and osteoclastogenesis induction in the bone remodeling cycle has drawn great attention, and will continue to be a focus of study. Furthermore, with the identification of periodontal ligament stem cells(PDLCs), the cytomechanics involved in OTM and periodontitis, will undoubtedly be a promising new direction.0Comments 3Citations
- [Show abstract] [Hide abstract] ABSTRACT: To determine the effect of compression-force on the expression of alkaline phosphatase (ALP), and ALP activity in cementoblasts. We performed this study in the State Key Laboratory of Oral Diseases, West China Stomatology Hospital, Sichuan University, Chengdu, Sichuan, China from October to December 2010. We exposed murine immortalized cementoblasts (OCCM-30) to 2000-ustrain compression-force at a frequency of 0.5 Hz for 1, 3, 6, 12, and 24 hours. We assayed the cellular ALP activity after the treatments. We used real-time polymerase chain reaction (RT-PCR) and western blot to examine the gene and protein expression of ALP in the OCCM-30 cells at each time point. Two-thousand ustrain compressive force significantly up-regulated the mRNA expression of ALP in OCCM-30 cells, which reached a peak at 12 hours loading, and the protein expression change of ALP in response to compression-force was consistent with the variation of gene level. We also noted marked enhancement of ALP activity in OCCM-30 cells during the application of mechanical stress. The compression-force increased the expression of ALP in OCCM-30 cells, suggesting that mechanical stimulation may affect the cellular function of cementoblasts by regulating ALP expression, which may participate in cementum metabolism during orthodontic tooth movement.0Comments 2Citations