ABSTRACT
Docosahexaenoic acid (DHA), an omega-3-fatty acid, modulates multiple cellular functions. In this study, we addressed the effects of DHA on human umbilical vein endothelial cell calcium transient and endothelial nitric oxide synthase (eNOS) phosphorylation under control and adenosine triphosphate (ATP, 100 µM) stimulated conditions. Cells were treated for 48 h with DHA concentrations from 3 to 50 µM. Calcium transient was measured using the fluorescent dye Fura-2-AM and eNOS phosphorylation was addressed by western blot. DHA dose-dependently reduced the ATP stimulated Ca²⁺-transient. This effect was preserved in the presence of BAPTA (10 and 20 µM) which chelated the intracellular calcium, but eliminated after withdrawal of extracellular calcium, application of 2-aminoethoxy-diphenylborane (75 µM) to inhibit store-operated calcium channel or thapsigargin (2 µM) to delete calcium store. In addition, DHA (12 µM) increased ser1177/thr495 phosphorylation of eNOS under baseline conditions but had no significant effect on this ratio under conditions of ATP stimulation. In conclusion, DHA dose-dependently inhibited the ATP-induced calcium transient, probably via store-operated calcium channels. Furthermore, DHA changed eNOS phosphorylation suggesting activation of the enzyme. Hence, DHA may shift the regulation of eNOS away from a Ca²⁺ activated mode to a preferentially controlled phosphorylation mode.
Subject(s)
Humans , Adenosine Triphosphate , Adenosine , Blotting, Western , Calcium Channels , Calcium , Endothelial Cells , Nitric Oxide Synthase Type III , Phosphorylation , Thapsigargin , Umbilical VeinsABSTRACT
Studies have shown that stromal interaction molecule 1(STIM1) is closely related to the development of tumors, and which is involved in the regulation of apoptosis, proliferation, migration and invasion in many human cancers. Blocking or knockdown of STIM1 can significantly inhibit the proliferation and migration of cancer cells. Elucidation of the regulatory mechanism of STIM1 in cancer cells will be helpful for the identification of new therapeutic targets. This paper reviews the mechanism of STIM1 molecule in different tumors and its clinical application.
ABSTRACT
AIM:To investigate the expression and function of store-operated calcium channels ( SOCC) in human circulating fibrocytes.METHODS:Peripheral blood mononuclear cells ( PBMCs) were isolated and cultured in ser-um-free media.After 7 d, the PBMCs differentiated into fibrocytes.RT-PCR and real-time PCR were performed to deter-mine the mRNA expression of ORAI1-3 and STIM1-2 in the fibrocytes.SOCC inhibitor SKF-96365 was used to elucidate the role of SOCC in the differentiation of fibrocytes.RESULTS:The results of real-time PCR showed that the mRNA ex-pression of ORAI1-3 and STIM1-2 was positive in cultured fibrocytes.SKF-96365 (10μmol/L) significantly inhibited the differentiation of fibrocytes.CONCLUSION:SOCC-related proteins ORAI1-3 and STIM1-2 are abundantly expressed in the fibrocytes, and may play an important role in the differentiation of these cells.
ABSTRACT
Store operated calcium channels (SOCCs) are referred to as plasma membrane calcium channels that are opened in response to a depletion of intracellular calcium stores. SOCCs are broadly distributed in excitable and non excitable cells, and may play important roles in conducting intracellular calcium signals, modulations of cell functions and gene expression. Although the current understanding of SOCCs related mechanism is still limited, the physiological significance of SOCCs and their possible links to certain diseases have been suggested. Future study of highly selective SOCCs modulating agents may promote not only related research, but also the development of novel therapeutic drugs.