Melatonin inhibits growth and metastasis of MDA-MB-231 breast cancer cells by activating autophagy / 南方医科大学学报

OBJECTIVE@#To investigate the effects of melatonin on the growth and metastasis of MDA-MB-231 breast cancer cells and explore the mechanism.@*METHODS@#MDA-MB-231 cells were treated with 1, 3 or 5 mmol/L melatonin, and the changes in cell proliferation were examined using CCK-8 assay. Colony-forming assay and wound healing assay were used to assess the effects of melatonin treatmnent on colony-forming ability and migration of the cells. Flow cytometry and immunofluoresnce assay were employed to examine apoptosis and positive staining for autophagy-related proteins in the cells treated with 3 mmol/L melatonin. The effects of melatonin treatment alone or in combination with 3-methyladenine (3-MA) on the expressions of the proteins associated with autophagy (LC3, P62 and Beclin1), apoptosis (Bcl2 and Bax) and epithelial-mesenchymal transition (E-cadherin and Snail) were examined with Western blotting.@*RESULTS@#Melatonin treatment significantly inhibited the proliferation of breast cancer cells in a concentration- and time-dependent manner (P < 0.05), suppressed colony-forming ability and migration (P < 0.01), and promoted apoptosis of the cells (P < 0.01). Melatonin treatment alone significantly increased the expressions of Bax (P < 0.05), E-cadherin, LC3-II/LC3-I, and Beclin1 and lowered the expressions of Bcl2 (P < 0.05), Snail, P62 (P < 0.05), and Bcl2/Bax ratio (P < 0.01) in the cells, and caused enhanced positive staining of Beclin1 protein and attenuated staining of P62 protein. Compared with melatonin treatment alone, melatonin treatment combined with 3-MA significantly decreased the expressions of Beclin1 (P < 0.001), LC3-II/LC3-I (P < 0.05), Bax (P < 0.01), and E-cadherin (P < 0.001) and increased the expressions of Bcl2 (P < 0.05), Snail, and Bcl2/Bax ratio (P < 0.01).@*CONCLUSION@#Melatonin can induce autophagy of MDA-MB-231 breast cancer cells to inhibit cell proliferation and metastasis and promote cell apoptosis, and suppressing autophagy can weaken the inhibitory effect of melatonin on the growth and metastasis of breast cancer cells.

Effect of 1,25(OH)2D3on type Ⅰ collagen secretion in adipose-derived mesenchymal stem cells and its mechanism / 中国组织工程研究

BACKGROUND: Adipose-derived mesenchymal stem cells (ADMSCs) have been reported to improve wound healing. However, type I collagen secreted by ADMSCs will contribute to scar formation. Therefore, inhibiting type I collagen secretion from ADMSCs will strengthen its clinical application. OBJECTIVE: To investigate the effect of 1,25(OH)2D3on secretion of type I collagen by ADMSCs and its mechanism. METHODS: Human ADMSCs were isolated by collagenase digestion, and identified by flow cytometry. ADMSCs at passage 4 were cultured in DMEM/F12 medium containing different concentrations of 1,25(OH)2D3(10-7, 10-8, 10-9, 10-10and 0 mol/L) respectively for 4 days. Then, the concentration of type I collagen in cell supernatant was measured by ELISA. Real-time PCR and western blot were used to detect the expression of Smad3 at mRNA and protein levels and phosphorylated protein Smad3 level in ADMSCs cultured with and without 1,25(OH)2D3. To analyze the contribution of Smad3 to the effect of 1,25(OH)2D3, Smad3 inhibitor was added to culture medium 30 minutes before adding 1,25(OH)2D3, and type I collagen in cell supernatant was detected by ELISA at 4 days after addition of SMAD3 inhibitor. RESULTS AND CONCLUSION: 1,25(OH)2D3inhibited the secretion of type I collagen by ADMSCs in a dose-dependent manner. The results of real-time PCR and western blot showed that the expression of Smad3 was upregulated by 1,25(OH)2D3, and the results of western blot showed that the phosphorylated Smad3 protein level in ADMSCs was significantly increased by 1,25(OH)2D3. Moreover, the inhibition of type I collagen secretion by 1,25(OH)2D3could be blocked by Smad3 inhibitor. These results indicate that 1,25(OH)2D3can inhibit the secretion of type I collagen from ADMSCs by up-regulating the expression of Smad3.

A Preliminary Study of the Therapeutic Role of Human Early Fetal Aorta-derived Endothelial Progenitor Cells in Inhibiting Carotid Artery Neointimal Hyperplasia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Endothelial cell damage is an important pathophysiological step of restenosis after angioplasty and stenting. Cell transplantation has great therapeutic potential for endothelial recovery. We investigated the effect of transplanting endothelial progenitor cells (EPCs) derived from human early fetal aortas in rat injured arteries.</p><p><b>METHODS</b>The carotid arterial endothelium of Sprague-Dawley rats was damaged by dilatation with a 1.5 F balloon catheter, and then EPCs derived from human early fetal aortas (<14 weeks) were injected into the lumen of the injured artery in transplanted rats, with an equal volume of normal saline injected into control rats. Rats were sacrificed at 2 and 4 weeks after treatment and transplanted cells were identified by immunohistochemical staining with anti-human CD31 and anti-human mitochondria antibodies. Arterial cross-sections were analyzed by pathology, immunohistochemistry, and morphometry.</p><p><b>RESULTS</b>Green fluorescence-labeled EPCs could be seen in the endovascular surface of balloon-injured vessels after transplantation. The intimal area and intimal/medial area ratio were significantly smaller in the transplanted group than in the control (P < 0.05) and the residual lumen area was larger (P < 0.05). After EPC transplantation, a complete vascular endothelial layer was formed, which was positive for human von Willebrand factor after immunohistochemical staining, and immunohistochemical staining revealed many CD31- and mitochondria-positive cells in the re-endothelialized endothelium with EPC transplantation but not control treatment.</p><p><b>CONCLUSION</b>EPCs derived from human early fetal aorta were successfully transplanted into injured vessels and might inhibit neointimal hyperplasia after vascular injury.</p>

CD133(+) cells derived from human placenta identified as initiating cells for LTC-IC colony formation / 中国实验血液学杂志

The aim of this study was to evaluate whether human placenta CD133(+) cells have an ability to reconstitute long-term hematopoiesis. Magnetic-activated cell sorting (MACS) was applied to enrich human placental CD133(+) cells. The isolated human placental CD133(+)cells of four different densities were established by limiting-dilution assay and primary fetal bone marrow stromal cells separated from bone marrow as feeder layer cells were co-cultured in long-term culture system so as to observe the incidence of long-term culture initiating-cells (LTC-IC) and their ability of proliferation and differentiation.The results showed that human placenta derived CD133(+) cells contained LTC-IC with frequency of 1/645 which have an ability to proliferate and differentiate into granulocyte/macrophage colony-forming units (CFU-GM) and mixed colony-forming units (CFU-Mix). In all LTC-IC positive wells, 71.43% form only CFU-GM and 28.57% display both CFU-GM and CFU-Mix formation. It is concluded that human placental CD133(+) cells possess LTC-IC with colony-forming capacity of hematopoietic early progenitor cells.