ABSTRACT
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.
Subject(s)
Female , Humans , Autophagy , Autophagy-Related Proteins/metabolism , Breast Neoplasms , Cell Line, Tumor , Melatonin/pharmacologyABSTRACT
<p><b>OBJECTIVE</b>To identify the specific protein interactions involved in Bat3-mediated apoptosis.</p><p><b>METHODS</b>Tandem affinity purification (TAP) was utilized to investigate Bat3-protein interactions, during which full-length human Bat3 fused with Strep2 and FLAG tag as a bait was used to screen the specific protein-protein interactions. The isolated proteins were identified with mass spectrometry.</p><p><b>RESULTS</b>TAP studies showed that Ubl4A was identified as a Bat3-binding partner. Further investigation using co-immunoprecipitation confirmed that Bat3 was associated with Ubl4A.</p><p><b>CONCLUSION</b>TAP was successfully established and is suitable for isolating the binding partners of Bat3.</p>
Subject(s)
Humans , Cell Line , Molecular Chaperones , Protein Binding , UbiquitinsABSTRACT
The present study was aimed to investigate whether Bcl-2, Fas and Bax are involved in monocyte chemotacitic protein-1 (MCP-1)-induced apoptosis of human umbilical vein endothelial cells (hUVECs). hUVECs were cultured, and the purity was identified by immunofluorescence and immunohistochemistry with specific anti-von Willebrand factor (vWF) and anti-VEGF receptor-2 (KDR) antibodies. With 90% confluence hUVECs were serum-starved for 12 h, and then treated with different concentrations of MCP-1 (0.1, 1.0, 10, 100 ng/mL) for 24 and 48 h respectively. The expressions of apoptosis related proteins Fas, Bcl-2, Bax were detected by flow cytometry (FACS) and Western blot. As shown in our preliminary study, MCP-1 induced apoptosis of hUVECs in a dose-dependent manner at both 24 h and 48 h. FACS and Western blot analysis results in the present study indicated that MCP-1 promoted the expression of proapoptotic proteins Bax and Fas and inhibited the expression of antiapoptotic protein Bcl-2. These results suggest that MCP-1 may induce the apoptosis of hUVECs through evoking the imbalance between proapoptotic Fas/Bax and antiapoptotic Bcl-2 protein.