Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous system.Axons in the central nervous system fail to regenerate,meaning that injurie...Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous system.Axons in the central nervous system fail to regenerate,meaning that injuries or diseases that cause loss of axonal connectivity have life-changing consequences.In 2008,genetic deletion of PTEN was identified as a means of stimulating robust regeneration in the optic nerve.PTEN is a phosphatase that opposes the actions of PI3-kinase,a family of enzymes that function to generate the membrane phospholipid PIP_(3) from PIP_(2)(phosphatidylinositol(3,4,5)-trisphosphate from phosphatidylinositol(4,5)-bisphosphate).Deletion of PTEN therefore allows elevated signaling downstream of PI3-kinase,and was initially demonstrated to promote axon regeneration by signaling through mTOR.More recently,additional mechanisms have been identified that contribute to the neuron-intrinsic control of regenerative ability.This review describes neuronal signaling pathways downstream of PI3-kinase and PIP3,and considers them in relation to both developmental and regenerative axon growth.We briefly discuss the key neuron-intrinsic mechanisms that govern regenerative ability,and describe how these are affected by signaling through PI3-kinase.We highlight the recent finding of a developmental decline in the generation of PIP_(3) as a key reason for regenerative failure,and summarize the studies that target an increase in signaling downstream of PI3-kinase to facilitate regeneration in the adult central nervous system.Finally,we discuss obstacles that remain to be overcome in order to generate a robust strategy for repairing the injured central nervous system through manipulation of PI3-kinase signaling.展开更多
Chen et al demonstrated that regulator of G protein signaling(RGS)4 promotes gastric cancer(GC)progression by activating the focal adhesion kinase/phospha-tidyl-inositol-3-kinase/protein kinase B pathway and inducing ...Chen et al demonstrated that regulator of G protein signaling(RGS)4 promotes gastric cancer(GC)progression by activating the focal adhesion kinase/phospha-tidyl-inositol-3-kinase/protein kinase B pathway and inducing epithelial-mesen-chymal transition.Although their multilevel approach integrating clinical data,functional assays,and xenograft models demonstrated a key role for RGS4 in GC pathogenesis,several limitations should be considered.The mechanism of the RGS4-focal adhesion kinase interaction remains unclear,specifically whether it involves direct binding or intermediaries.The clinical analysis of 90 patients lacks stratification by GC subtypes or immune features,potentially limiting generaliz-ability.Furthermore,fully validating RGS4’s oncogenic role requires additional studies,including functional assays in chemotherapy-resistant and metastatic cell lines,metastasis models including orthotopic implantation and tail vein injection,and comparison with other RGS family members.Addressing these via targeted mechanistic studies and expanded clinical validation could strengthen RGS4’s po-tential as a therapeutic target in GC.展开更多
基金the Medical Research Council(MR/R004544/1,MR/R004463/1,to RE)EU ERA-NET NEURON(AxonRepair grant,to BN)+1 种基金Fight for Sight(5119/5120,and 5065-5066,to RE)National Eye Research Centre(to RE).
文摘Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous system.Axons in the central nervous system fail to regenerate,meaning that injuries or diseases that cause loss of axonal connectivity have life-changing consequences.In 2008,genetic deletion of PTEN was identified as a means of stimulating robust regeneration in the optic nerve.PTEN is a phosphatase that opposes the actions of PI3-kinase,a family of enzymes that function to generate the membrane phospholipid PIP_(3) from PIP_(2)(phosphatidylinositol(3,4,5)-trisphosphate from phosphatidylinositol(4,5)-bisphosphate).Deletion of PTEN therefore allows elevated signaling downstream of PI3-kinase,and was initially demonstrated to promote axon regeneration by signaling through mTOR.More recently,additional mechanisms have been identified that contribute to the neuron-intrinsic control of regenerative ability.This review describes neuronal signaling pathways downstream of PI3-kinase and PIP3,and considers them in relation to both developmental and regenerative axon growth.We briefly discuss the key neuron-intrinsic mechanisms that govern regenerative ability,and describe how these are affected by signaling through PI3-kinase.We highlight the recent finding of a developmental decline in the generation of PIP_(3) as a key reason for regenerative failure,and summarize the studies that target an increase in signaling downstream of PI3-kinase to facilitate regeneration in the adult central nervous system.Finally,we discuss obstacles that remain to be overcome in order to generate a robust strategy for repairing the injured central nervous system through manipulation of PI3-kinase signaling.
文摘Chen et al demonstrated that regulator of G protein signaling(RGS)4 promotes gastric cancer(GC)progression by activating the focal adhesion kinase/phospha-tidyl-inositol-3-kinase/protein kinase B pathway and inducing epithelial-mesen-chymal transition.Although their multilevel approach integrating clinical data,functional assays,and xenograft models demonstrated a key role for RGS4 in GC pathogenesis,several limitations should be considered.The mechanism of the RGS4-focal adhesion kinase interaction remains unclear,specifically whether it involves direct binding or intermediaries.The clinical analysis of 90 patients lacks stratification by GC subtypes or immune features,potentially limiting generaliz-ability.Furthermore,fully validating RGS4’s oncogenic role requires additional studies,including functional assays in chemotherapy-resistant and metastatic cell lines,metastasis models including orthotopic implantation and tail vein injection,and comparison with other RGS family members.Addressing these via targeted mechanistic studies and expanded clinical validation could strengthen RGS4’s po-tential as a therapeutic target in GC.
