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ObjectiveTo investigate the effects of hydroxycamptothecin liposomes （LHCPT） on myocardial fibrosis in rats with heart failure by regulating the sphingosine kinase 1 （SphK1）/sphingosine-1-phosphate （S1P） signaling pathway. MethodsSD rats were divided into control group， model group， hydroxycamptothecin （HCPT） group， LHCPT group， captopril group， and LHCPT+K6PC-5 （SphK1 activator） group， with 12 rats in each group. The heart failure rat models in all groups except the control group were established by intraperitoneal injection of doxorubicin and then the corresponding drugs were given once a day. After four weeks， we applied color Doppler ultrasound to detect left ventricular end systolic diameter （LVESD）， left ventricular end diastolic diameter （LVEDD）， and left ventricular ejection fraction （LVEF） in rats； HE and Masson staining for myocardial pathological damage and myocardial fibrosis in rats， respectively； ELISA method for the levels of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in rat myocardial tissues； qRT-PCR for the expression of transforming growth factor-β1 （TGF-β1）， type I collagen （Collagen I）， and type Ⅲ collagen （Collagen Ⅲ） in rat myocardial tissues； Western blot for the expression of SphK1 and S1P proteins in rat myocardial tissues. ResultsCompared with the control group， the model group showed severe myocardial pathological damage and myocardial fibrosis， increased LVESD， LVEDD， levels of TNF-α and IL-6， expression of TGF-β1， Collagen I， Collagen Ⅲ， SphK1， S1P and decreased LVEF （P<0.05）. Compared with the model group， the HCPT group， LHCPT group and captopril group showed alleviated myocardial pathological damage and myocardial fibrosis， decreased LVESD， LVEDD， levels of TNF-α and IL-6， expression of TGF-β1， Collagen I， Collagen Ⅲ， SphK1， S1P and increased LVEF （P<0.05）. Compared with the LHCPT group， the LHCPT+K6PC-5 group showed aggravated myocardial pathological damage and myocardial fibrosis， increased LVESD， LVEDD， levels of TNF-α and IL-6， expression of TGF-β1， Collagen I， Collagen Ⅲ， SphK1， S1P and decreased LVEF （P<0.05）. ConclusionLHCPT may inhibit myocardial fibrosis in heart failure rats by inhibiting the SphK1/S1P signaling pathway.
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@#Sphingosine kinase 1 (SphK1) is an important protein that regulates the lipid microenvironment of cell membranes, and plays an important role in the dynamic equilibrium of ceramide, sphingosine and sphingosine-1-phosphate.The overexpression of SphK1 is closely related to the occurrence, development and migration of tumors as well as the generation of drug resistance.SphK1 inhibitors can induce apoptosis of various tumor cells and reverse drug resistance, which has a good prospect for drug development.In this article, the structural biology of SphK1, the structural types and structure-activity relationships of SphK1 inhibitors are reviewed.
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Objective To examine the role of SPHK-1/S1P and NFκB p65 signal pathway in non-small cell lung cancer (NSCLC)drug-resistant cells.Methods The drug-resistant cell line of lung cancer H460/DDP was constructed and its biological characteristics were identified successfully.The expression of SPHK-l was tested by RT-PCR and Western blot methods.S1 P and some proteins related to NFκB pathway were studied by Western blot. Results The drug-resistant lung cancer cell line H460/DDP was constructed and its drug-resistant ability was evaluated (IC50H460/DDP = 50.62μg/mL, RIH460/DDP = 2.95 ). Cisplatin at a concentration of 10 - 80 μg/mL significantly decreased cell death of drug-resistant cell line (P<0 .01 ).Western blot assay analysis showed that overexpressions of SPHK-l,S1 P and NFκB p65 were significantly higher in drug-resistant cell line than in their parent cell line H460 (P=0.0415,P=0.0465,P=0.0218).RT-PCR method revealed that SPHK-1 mRNA was overexpressed in drug-resistant cell line compared with that in their parent cell line H460 (P<0.05).More NFκB p65 protein in cell nucleus was expressed in drug-resistant cells than in parent cells.Conclusion SPHK-1/S1P and NFκB p65 signal pathway may play an improtant role in the drug-resistant H460 cell line in non-small cell lung cancer.