The interaction between the lactate receptor GPR81(also known as hydroxycarboxylic acid receptor 1,or HCAR1)and Splicing Factor Proline-and Glutamine-Rich protein promotes the tumor cell malignancy.GPR81 nuclear trans...The interaction between the lactate receptor GPR81(also known as hydroxycarboxylic acid receptor 1,or HCAR1)and Splicing Factor Proline-and Glutamine-Rich protein promotes the tumor cell malignancy.GPR81 nuclear translocation plays an important role in driving cancer progression and could serve as a potential therapeutic target.Yang et al concluded in their study that lactate and its receptor,GPR81,play crucial roles in cancer progression,and are key players in linking the lactate-rich tumor microenvironment to cancer cell behavior.The ability of nuclear GPR81 to directly regulate gene expression,combined with extracellular matrix-mediated mechanical signaling,creates a potentially robust system for the coordinated adaptation and survival of cancer cells.Understanding these interactions could lead to the discovery of new therapeutic targets and improved treatment strategies for cancer.展开更多
BACKGROUND The Warburg effect is common in cancers.Lactate and its receptor GPR81 play an important role in cancer progression.It is widely accepted that membrane receptor nuclear translocation plays some novel role i...BACKGROUND The Warburg effect is common in cancers.Lactate and its receptor GPR81 play an important role in cancer progression.It is widely accepted that membrane receptor nuclear translocation plays some novel role in cancer pathology.The mechanism by which the lactate/GPR81 axis regulates cancer malignancy remains unclear.AIM To elucidate the mechanism of GPR81 nuclear transportation promoted by exogenous lactate.METHODS Lung cancer cells were stimulated with exogenous lactate and GPR81 levels were measured by immunofluoresence and western blot analysis in membrane,cytoplasmic,and nuclear fractions.Lung cancer cells were transduced with a mutant GPR81 nuclear localization signal(NLS)construct,wild type GPR81 or empty vector and used to examine how GPR81 nuclear transportation affects lung cancer cells malignancy in vitro and in vivo.Immunoprecipitation Proteomics analysis and Chromatin immunoprecipitation(ChIP)sequencing were used to determine GPR81 interacting proteins and genes.RESULTS In response to hypoxia/Lactate stimulation,GPR81 translocates and accumulates in the nucleus of lung cancer cells.Functionally,GPR81 nuclear translocation promotes cancer cell proliferation and motility.Depletion of the GPR81 NLS depletes GPR81 nuclear levels and decreases cancer cell growth and invasion in vitro,as well as cancer cell malignancy in vivo.Proteomics analysis revealed a set of proteins including SFPQ,that interact with GPR81 in the cancer cell nucleus.Notably,the interaction of GPR81 with SFPQ promotes cancer cell growth and motility.ChIP sequencing analysis discovered that there is a set of genes targeted by GPR81.CONCLUSION The interaction of GPR81 with SFPQ promotes cancer cell malignancy.GPR81 nuclear translocation is critical in conferring cancer progression and may be a potential therapeutic target for limiting cancer progression.展开更多
目的探索G蛋白偶联受体81(G-protein coupled receptor 81,GPR81)和线粒体外膜异位酶20(translocase of the outer mitochondrial membrane member 20,TOMM20)在下咽癌中的功能及临床意义。方法选取30例经病理检查确诊为下咽鳞状细胞癌...目的探索G蛋白偶联受体81(G-protein coupled receptor 81,GPR81)和线粒体外膜异位酶20(translocase of the outer mitochondrial membrane member 20,TOMM20)在下咽癌中的功能及临床意义。方法选取30例经病理检查确诊为下咽鳞状细胞癌患者的下咽癌组织和癌旁组织,对患者临床资料进行统计学分析,并运用免疫组织化学方法检测GPR81和TOMM20在癌组织及癌旁组织中的表达。经特定浓度的顺铂诱导Fadu细胞,分别诱导0、12、24及48h,经Real-time PCR及Western Blot检测GPR81、TOMM20在mRNA和蛋白质水平的变化。采用流式细胞术检测顺铂刺激Fadu细胞后细胞凋亡情况。结果GPR81和TOMM20在下咽癌组织的表达水平显著高于癌旁组织,差异具有统计学意义(P<0.05)。在下咽癌中,临床分期为I、II期的下咽癌中GPR81、TOMM20显著低于Ⅲ、IV期(P<0.05)。有淋巴结转移的下咽癌组织中GPR81、TOMM20的表达显著高于无淋巴结转移的下咽癌组织(P<0.05)。GPR81在中低分化的下咽癌中具有较高表达,在高分化下咽癌中表达较低,差异具有统计学意义(P<0.05)。不同分化程度的下咽癌中TOMM20的表达差异无统计学意义(P>0.05)。顺铂诱导Fadu细胞中GPR81及TOMM20的表达随时间呈现递减趋势,其mRNA水平及蛋白水平48h表达量与对照组相比,差异无统计学意义(P>0.05)。顺铂刺激的Fadu细胞中细胞凋亡数约为(11.35±0.87)%,对照组中细胞凋亡数为(18.68±0.33)%,两者经比较差异具有统计学意义(P<0.05)。结论GPR81、TOMM20可能与下咽癌的发生有关,二者可能参与了下咽癌化疗抵抗。因此能量代谢相关蛋白靶向研究或许是治疗侵袭性肿瘤的一个方向。展开更多
Background:Retinal pigment epithelium(RPE)is vital for the homeostasis of the subretina including photoreceptors and choroid.Interestingly,our previous results suggested that the recently discovered lactate receptor G...Background:Retinal pigment epithelium(RPE)is vital for the homeostasis of the subretina including photoreceptors and choroid.Interestingly,our previous results suggested that the recently discovered lactate receptor GPR81 is abundantly expressed in RPE.To date,only one previous study has shown that activating GPR81 could enhance DNA repair by activating HDAC1.Consequently,we investigated whether GPR81 exhibits epigenetic modification in the subretina by using GPR81−/−mice.Methods:GPR81−/−mice and wide type littermates were generated on a background of C57BL/6J mice.The thicknesses of their choroid were evaluated by immunohistochemistry.Meanwhile,Q-PCR,western blot and choroid sprout assay were performed.In vitro,primary retinal pigment epithelium(pRPE)cells were isolated from mice,and cultured for treatments.Results:The thickness of choroid was reduced in GPR81−/−mice compared to GPR81+/+mice,suggesting that GPR81 is important for the integrity of choroid.In the choroid sprout assay,lactate treated RPE/choroid complex showed a significant increase in angiogenesis compared to controls while lactate treated KO RPE/choroid complex showed no difference compared to their controls.For Q-PCR,most of the genes screened elevated their expression in GPR81−/−mice compared to WT mice,suggesting epigenetic modification may exist,which were confirmed by histone acetylation and HDACs activity assay.Conclusions:Taking together,the lactate receptor GPR81 in RPE is very important for maintaining homeostasis of the subretina.This novel discovery sheds new light on the relationship between metabolism and epigenetic modification.展开更多
Aim:Lactate can signal through the endogenous lactate receptor,GPR81,which is expressed in some cancers.Lactate metabolism is altered by the metastasis-promoting process of epithelial-mesenchymal transition(EMT).This ...Aim:Lactate can signal through the endogenous lactate receptor,GPR81,which is expressed in some cancers.Lactate metabolism is altered by the metastasis-promoting process of epithelial-mesenchymal transition(EMT).This study examined the expression and function of GPR81 in breast cancer samples,and in receptor-positive epithelial vs.triple-negative post-EMT mesenchymal breast cancer cells.Methods:GPR81 mRNA expression was examined by breast cancer microarray,and by a Kaplan-Meier survival curve.Using 3-dimensional culture conditions,GPR81 mRNA expression in epithelial and mesenchymal breast cancer cell lines was measured by qRT-PCR.GPR81 siRNA was used to assess the role of GPR81,alone or in conjunction with tamoxifen,in the regulation of MCT1 and MCT4 lactate transporters,intracellular lactate,and cell proliferation and survival.Results:GPR81 mRNA levels were elevated in receptor-positive breast cancer,relative to non-tumor and triple-negative samples,and correlated with increased survival.GPR81 expression was elevated in the two epithelial breast cancer cell lines vs.the corresponding post-EMT mesenchymal cell lines.GPR81 knock-down in epithelial MCF7 cells caused:1,selectively lower mRNA and protein expression of the MCT1 transporter,but not MCT2 or MCT4 ;transporters;2,lower levels of intracellular lactate;and 3,decreased proliferation and survival in lactate only-containing conditions.GPR81 siRNA plus tamoxifen displayed additive suppressive effects on MCT1 expression and cell viability.Conclusion:GPR81 promotes the ability of epithelial breast cancer cells to import lactate for energy use.As such,GPR81 represents a potential target for treatment of hormone-positive breast cancer cells,and may be prognostic for higher grade breast cancer.展开更多
文摘The interaction between the lactate receptor GPR81(also known as hydroxycarboxylic acid receptor 1,or HCAR1)and Splicing Factor Proline-and Glutamine-Rich protein promotes the tumor cell malignancy.GPR81 nuclear translocation plays an important role in driving cancer progression and could serve as a potential therapeutic target.Yang et al concluded in their study that lactate and its receptor,GPR81,play crucial roles in cancer progression,and are key players in linking the lactate-rich tumor microenvironment to cancer cell behavior.The ability of nuclear GPR81 to directly regulate gene expression,combined with extracellular matrix-mediated mechanical signaling,creates a potentially robust system for the coordinated adaptation and survival of cancer cells.Understanding these interactions could lead to the discovery of new therapeutic targets and improved treatment strategies for cancer.
文摘BACKGROUND The Warburg effect is common in cancers.Lactate and its receptor GPR81 play an important role in cancer progression.It is widely accepted that membrane receptor nuclear translocation plays some novel role in cancer pathology.The mechanism by which the lactate/GPR81 axis regulates cancer malignancy remains unclear.AIM To elucidate the mechanism of GPR81 nuclear transportation promoted by exogenous lactate.METHODS Lung cancer cells were stimulated with exogenous lactate and GPR81 levels were measured by immunofluoresence and western blot analysis in membrane,cytoplasmic,and nuclear fractions.Lung cancer cells were transduced with a mutant GPR81 nuclear localization signal(NLS)construct,wild type GPR81 or empty vector and used to examine how GPR81 nuclear transportation affects lung cancer cells malignancy in vitro and in vivo.Immunoprecipitation Proteomics analysis and Chromatin immunoprecipitation(ChIP)sequencing were used to determine GPR81 interacting proteins and genes.RESULTS In response to hypoxia/Lactate stimulation,GPR81 translocates and accumulates in the nucleus of lung cancer cells.Functionally,GPR81 nuclear translocation promotes cancer cell proliferation and motility.Depletion of the GPR81 NLS depletes GPR81 nuclear levels and decreases cancer cell growth and invasion in vitro,as well as cancer cell malignancy in vivo.Proteomics analysis revealed a set of proteins including SFPQ,that interact with GPR81 in the cancer cell nucleus.Notably,the interaction of GPR81 with SFPQ promotes cancer cell growth and motility.ChIP sequencing analysis discovered that there is a set of genes targeted by GPR81.CONCLUSION The interaction of GPR81 with SFPQ promotes cancer cell malignancy.GPR81 nuclear translocation is critical in conferring cancer progression and may be a potential therapeutic target for limiting cancer progression.
文摘目的探索G蛋白偶联受体81(G-protein coupled receptor 81,GPR81)和线粒体外膜异位酶20(translocase of the outer mitochondrial membrane member 20,TOMM20)在下咽癌中的功能及临床意义。方法选取30例经病理检查确诊为下咽鳞状细胞癌患者的下咽癌组织和癌旁组织,对患者临床资料进行统计学分析,并运用免疫组织化学方法检测GPR81和TOMM20在癌组织及癌旁组织中的表达。经特定浓度的顺铂诱导Fadu细胞,分别诱导0、12、24及48h,经Real-time PCR及Western Blot检测GPR81、TOMM20在mRNA和蛋白质水平的变化。采用流式细胞术检测顺铂刺激Fadu细胞后细胞凋亡情况。结果GPR81和TOMM20在下咽癌组织的表达水平显著高于癌旁组织,差异具有统计学意义(P<0.05)。在下咽癌中,临床分期为I、II期的下咽癌中GPR81、TOMM20显著低于Ⅲ、IV期(P<0.05)。有淋巴结转移的下咽癌组织中GPR81、TOMM20的表达显著高于无淋巴结转移的下咽癌组织(P<0.05)。GPR81在中低分化的下咽癌中具有较高表达,在高分化下咽癌中表达较低,差异具有统计学意义(P<0.05)。不同分化程度的下咽癌中TOMM20的表达差异无统计学意义(P>0.05)。顺铂诱导Fadu细胞中GPR81及TOMM20的表达随时间呈现递减趋势,其mRNA水平及蛋白水平48h表达量与对照组相比,差异无统计学意义(P>0.05)。顺铂刺激的Fadu细胞中细胞凋亡数约为(11.35±0.87)%,对照组中细胞凋亡数为(18.68±0.33)%,两者经比较差异具有统计学意义(P<0.05)。结论GPR81、TOMM20可能与下咽癌的发生有关,二者可能参与了下咽癌化疗抵抗。因此能量代谢相关蛋白靶向研究或许是治疗侵袭性肿瘤的一个方向。
文摘Background:Retinal pigment epithelium(RPE)is vital for the homeostasis of the subretina including photoreceptors and choroid.Interestingly,our previous results suggested that the recently discovered lactate receptor GPR81 is abundantly expressed in RPE.To date,only one previous study has shown that activating GPR81 could enhance DNA repair by activating HDAC1.Consequently,we investigated whether GPR81 exhibits epigenetic modification in the subretina by using GPR81−/−mice.Methods:GPR81−/−mice and wide type littermates were generated on a background of C57BL/6J mice.The thicknesses of their choroid were evaluated by immunohistochemistry.Meanwhile,Q-PCR,western blot and choroid sprout assay were performed.In vitro,primary retinal pigment epithelium(pRPE)cells were isolated from mice,and cultured for treatments.Results:The thickness of choroid was reduced in GPR81−/−mice compared to GPR81+/+mice,suggesting that GPR81 is important for the integrity of choroid.In the choroid sprout assay,lactate treated RPE/choroid complex showed a significant increase in angiogenesis compared to controls while lactate treated KO RPE/choroid complex showed no difference compared to their controls.For Q-PCR,most of the genes screened elevated their expression in GPR81−/−mice compared to WT mice,suggesting epigenetic modification may exist,which were confirmed by histone acetylation and HDACs activity assay.Conclusions:Taking together,the lactate receptor GPR81 in RPE is very important for maintaining homeostasis of the subretina.This novel discovery sheds new light on the relationship between metabolism and epigenetic modification.
基金the Fund for Biology from the Cell Biology Department at the University of Connecticut Health Center
文摘Aim:Lactate can signal through the endogenous lactate receptor,GPR81,which is expressed in some cancers.Lactate metabolism is altered by the metastasis-promoting process of epithelial-mesenchymal transition(EMT).This study examined the expression and function of GPR81 in breast cancer samples,and in receptor-positive epithelial vs.triple-negative post-EMT mesenchymal breast cancer cells.Methods:GPR81 mRNA expression was examined by breast cancer microarray,and by a Kaplan-Meier survival curve.Using 3-dimensional culture conditions,GPR81 mRNA expression in epithelial and mesenchymal breast cancer cell lines was measured by qRT-PCR.GPR81 siRNA was used to assess the role of GPR81,alone or in conjunction with tamoxifen,in the regulation of MCT1 and MCT4 lactate transporters,intracellular lactate,and cell proliferation and survival.Results:GPR81 mRNA levels were elevated in receptor-positive breast cancer,relative to non-tumor and triple-negative samples,and correlated with increased survival.GPR81 expression was elevated in the two epithelial breast cancer cell lines vs.the corresponding post-EMT mesenchymal cell lines.GPR81 knock-down in epithelial MCF7 cells caused:1,selectively lower mRNA and protein expression of the MCT1 transporter,but not MCT2 or MCT4 ;transporters;2,lower levels of intracellular lactate;and 3,decreased proliferation and survival in lactate only-containing conditions.GPR81 siRNA plus tamoxifen displayed additive suppressive effects on MCT1 expression and cell viability.Conclusion:GPR81 promotes the ability of epithelial breast cancer cells to import lactate for energy use.As such,GPR81 represents a potential target for treatment of hormone-positive breast cancer cells,and may be prognostic for higher grade breast cancer.
