AIM: To examine the expression of Sph K1, an oncogenic kinase that produces sphingosine 1-phosphate(S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid(LPA) receptor overexpressed in ...AIM: To examine the expression of Sph K1, an oncogenic kinase that produces sphingosine 1-phosphate(S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid(LPA) receptor overexpressed in various cancers, in human colorectal cancer.METHODS: Real-time reverse-transcription polymerase chain reaction was used to measure the m RNA expression of Sph K1, LPAR2, and the three major S1 P receptors in 27 colorectal cancer samples and corresponding normal tissue samples. We also examined the correlation between the expression of Sph K1 and LPAR2.RESULTS: C o l o r e c t a l c a n c e r t i s s u e i n 2 2 o f 2 7 patients had higher levels of Sph K1 m RNA than in normal tissue. In two-thirds of the samples, Sph K1 m RNA expression was more than two-fold higher than in normal tissue. Consistent with previous reports, LPAR2 m RNA expression in 20 of 27 colorectal cancer tissue samples was higher compared to normal tissue samples. Expression profiles of all three major S1 P receptors, S1PR1, S1PR2, and S1PR3, varied without any trend, with no significant difference in expression between cancer and normal tissues. A highly significant positive correlation was found between Sph K1 and LPAR2 expression [Pearson's correlation coefficient(r) = 0.784 and P < 0.01]. The m RNA levels of Sph K1 and LPAR2 did not correlate with TNM stage.CONCLUSION: Our findings suggest that S1 P andLPA may play important roles in the development ofcolorectal cancer via the upregulation of Sph K1 andLPAR2, both of which could serve as new therapeutictargets in the treatment of colorectal cancer.展开更多
Objective To investigate the role of extracellular signal-regulated kinase(ERK) in apoptosis of human colon cancer(HCT116) cells. Methods After the HCT116 cells were pretreated with specific ERK inhibitor(U0126) or sp...Objective To investigate the role of extracellular signal-regulated kinase(ERK) in apoptosis of human colon cancer(HCT116) cells. Methods After the HCT116 cells were pretreated with specific ERK inhibitor(U0126) or specific siRNA and exposed to 10 mmol/L sodium butyrate(NaBT) for 24 h, their apoptosis was detected by flow cytometry, levels of SphK2 and ERK protein were measured by Western blot, and translocation of SphK2 was assayed by immunofluorescence microscopy. Results The U0126 and siRNAs specific for SphK2 blocked the export of SphK2 from nuclei to cytoplasm and increased the apoptosis of HCT116 cells following NaBT exposure. Over-expression of PKD decreased NaBT-induced apoptosis of HCT116 cells, which was reversed by U0126. Furthermore, transfection of HCT116 cells with constitutively activated PKD plasmids recovered the U0126-blocked export of SphK2. Conclusion ERK regulates the export of SphK2 and apoptosis of HCT116 cells by modulating PKD. Modulation of these molecules may help increase the sensitivity of colon cancer cells to the physiologic anti-colon cancer agent, NaBT.展开更多
Aim This study is aimed to determine whether SPK2 （Sphingosine kinase-2） is involved in isoflurane preconditioning induced autophagy activation in primary cultured neurons. We also examined whether SPK2 pro- tects n...Aim This study is aimed to determine whether SPK2 （Sphingosine kinase-2） is involved in isoflurane preconditioning induced autophagy activation in primary cultured neurons. We also examined whether SPK2 pro- tects neurons from ischemic injury by activating autophagy, and explored the molecular mechanism of SPK2 contrib- uting to the autophagy activation in neurons. Methods Isoflurane preconditioning （ISO） and oxygen glucose dep- rivation （OGD） model was established in primary cultured murine cortical neurons. Neurons were transfected by siRNA to interfere SPK2 and Beclin 1, or lentivirus to overexpress SPK2. Protein expression of SPK2, LC3, and Beclinl were detected with immunofluorescence and Western blot analysis. The neurons were treated with lysosomal inhibitor ammonium chloride （NH4 C1） to test the autophagy flux. The protection of SPK2 on OGD/R induced neu- ronal death was detected with CCK-8 （cell counting kit-8） and LDH cytotoxicity assay kit. Autophagy inhibitor 3- MA （3-Methyladenine） was used to detect the protection of autophagy on SPK2 induced isehemie tolerance. Co-im- munoprecipitation was used to detect the interaction between Beclin 1 and Bel-2. Results In primary cultured neu- ISO enhanced SPK2 and LC3 immunofluorescenee. SPK2 siRNA inhibits LC3II upregulation induced by rons, ISO. Beclin 1 siRNA also inhibits LC3II upregulation induced by ISO. Lentivirus-indueed SPK2 overexpression in- creased LC3II/LC3I ratio and enhanced the autophagy flux in neurons. SPK2 overexpression also exerted neuropro- teetion against OGD model in cortical neurons, as evidenced by improvement of neuronal morphology, increased cellular viability and reduced LDH leakage, while 3-MA partly abolished the SPK2-induced neuroprotection. After SPK2 overexpression, Beclin 1 siRNA inhibited SPK2 induced LC3II upregulation, and the coimmunoprecipitation of Beclin 1 and Bcl-2 was reduced.. Conclusion ISO increases SPK2 and activates autophagy in neurons. SPK2 or Beclin 1 interference cancels ISO induced autophagy activation. SPK2 overexpression activates autophagy, and protects the neurons against ischemic injury. SPK2 may induce autophagy by disrupting Beclin 1/Bcl-2 interaction.展开更多
Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac p...Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac protection.Our previous work found that sphingosine-1-phosphate(S1P)could ameliorate cardiac hypertrophy.In this study,we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.Methods:Eight-week-old male C57BL/6 mice were randomly divided into a sham,transverse aortic constriction(TAC)or a TAC+S1P treatment group.Results:We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease inα-smooth muscle actin(α-SMA)and collagen type I(COL I)expression compared with the TAC group.We also found that one of the key S1P enzymes,sphingosine kinase 2(SphK2),which was mainly distributed in cytoblasts,was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro.In addition,our in vitro results showed that S1P treatment activated extracellular regulated protein kinases(ERK)phosphorylation mainly through the S1P receptor 2(S1PR2)and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.Conclusion:These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart.This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.展开更多
基金Supported by Grant 2010 from Tokyo MetropolisJapan
文摘AIM: To examine the expression of Sph K1, an oncogenic kinase that produces sphingosine 1-phosphate(S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid(LPA) receptor overexpressed in various cancers, in human colorectal cancer.METHODS: Real-time reverse-transcription polymerase chain reaction was used to measure the m RNA expression of Sph K1, LPAR2, and the three major S1 P receptors in 27 colorectal cancer samples and corresponding normal tissue samples. We also examined the correlation between the expression of Sph K1 and LPAR2.RESULTS: C o l o r e c t a l c a n c e r t i s s u e i n 2 2 o f 2 7 patients had higher levels of Sph K1 m RNA than in normal tissue. In two-thirds of the samples, Sph K1 m RNA expression was more than two-fold higher than in normal tissue. Consistent with previous reports, LPAR2 m RNA expression in 20 of 27 colorectal cancer tissue samples was higher compared to normal tissue samples. Expression profiles of all three major S1 P receptors, S1PR1, S1PR2, and S1PR3, varied without any trend, with no significant difference in expression between cancer and normal tissues. A highly significant positive correlation was found between Sph K1 and LPAR2 expression [Pearson's correlation coefficient(r) = 0.784 and P < 0.01]. The m RNA levels of Sph K1 and LPAR2 did not correlate with TNM stage.CONCLUSION: Our findings suggest that S1 P andLPA may play important roles in the development ofcolorectal cancer via the upregulation of Sph K1 andLPAR2, both of which could serve as new therapeutictargets in the treatment of colorectal cancer.
基金supported by National Natural Science Foundation of China(81272180)National Basic Research Program of China(2012CB518200)
文摘Objective To investigate the role of extracellular signal-regulated kinase(ERK) in apoptosis of human colon cancer(HCT116) cells. Methods After the HCT116 cells were pretreated with specific ERK inhibitor(U0126) or specific siRNA and exposed to 10 mmol/L sodium butyrate(NaBT) for 24 h, their apoptosis was detected by flow cytometry, levels of SphK2 and ERK protein were measured by Western blot, and translocation of SphK2 was assayed by immunofluorescence microscopy. Results The U0126 and siRNAs specific for SphK2 blocked the export of SphK2 from nuclei to cytoplasm and increased the apoptosis of HCT116 cells following NaBT exposure. Over-expression of PKD decreased NaBT-induced apoptosis of HCT116 cells, which was reversed by U0126. Furthermore, transfection of HCT116 cells with constitutively activated PKD plasmids recovered the U0126-blocked export of SphK2. Conclusion ERK regulates the export of SphK2 and apoptosis of HCT116 cells by modulating PKD. Modulation of these molecules may help increase the sensitivity of colon cancer cells to the physiologic anti-colon cancer agent, NaBT.
文摘Aim This study is aimed to determine whether SPK2 （Sphingosine kinase-2） is involved in isoflurane preconditioning induced autophagy activation in primary cultured neurons. We also examined whether SPK2 pro- tects neurons from ischemic injury by activating autophagy, and explored the molecular mechanism of SPK2 contrib- uting to the autophagy activation in neurons. Methods Isoflurane preconditioning （ISO） and oxygen glucose dep- rivation （OGD） model was established in primary cultured murine cortical neurons. Neurons were transfected by siRNA to interfere SPK2 and Beclin 1, or lentivirus to overexpress SPK2. Protein expression of SPK2, LC3, and Beclinl were detected with immunofluorescence and Western blot analysis. The neurons were treated with lysosomal inhibitor ammonium chloride （NH4 C1） to test the autophagy flux. The protection of SPK2 on OGD/R induced neu- ronal death was detected with CCK-8 （cell counting kit-8） and LDH cytotoxicity assay kit. Autophagy inhibitor 3- MA （3-Methyladenine） was used to detect the protection of autophagy on SPK2 induced isehemie tolerance. Co-im- munoprecipitation was used to detect the interaction between Beclin 1 and Bel-2. Results In primary cultured neu- ISO enhanced SPK2 and LC3 immunofluorescenee. SPK2 siRNA inhibits LC3II upregulation induced by rons, ISO. Beclin 1 siRNA also inhibits LC3II upregulation induced by ISO. Lentivirus-indueed SPK2 overexpression in- creased LC3II/LC3I ratio and enhanced the autophagy flux in neurons. SPK2 overexpression also exerted neuropro- teetion against OGD model in cortical neurons, as evidenced by improvement of neuronal morphology, increased cellular viability and reduced LDH leakage, while 3-MA partly abolished the SPK2-induced neuroprotection. After SPK2 overexpression, Beclin 1 siRNA inhibited SPK2 induced LC3II upregulation, and the coimmunoprecipitation of Beclin 1 and Bcl-2 was reduced.. Conclusion ISO increases SPK2 and activates autophagy in neurons. SPK2 or Beclin 1 interference cancels ISO induced autophagy activation. SPK2 overexpression activates autophagy, and protects the neurons against ischemic injury. SPK2 may induce autophagy by disrupting Beclin 1/Bcl-2 interaction.
基金supported by the National Natural Science Foundation of China(No.81873505).
文摘Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac protection.Our previous work found that sphingosine-1-phosphate(S1P)could ameliorate cardiac hypertrophy.In this study,we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.Methods:Eight-week-old male C57BL/6 mice were randomly divided into a sham,transverse aortic constriction(TAC)or a TAC+S1P treatment group.Results:We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease inα-smooth muscle actin(α-SMA)and collagen type I(COL I)expression compared with the TAC group.We also found that one of the key S1P enzymes,sphingosine kinase 2(SphK2),which was mainly distributed in cytoblasts,was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro.In addition,our in vitro results showed that S1P treatment activated extracellular regulated protein kinases(ERK)phosphorylation mainly through the S1P receptor 2(S1PR2)and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.Conclusion:These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart.This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.
