Background:Ossification of the posterior longitudinal ligament(OPLL)is a prevalent condition in orthopedics.While death-associated protein kinase 2(DAPK2)is known to play roles in cellular apoptosis and autophagy,its ...Background:Ossification of the posterior longitudinal ligament(OPLL)is a prevalent condition in orthopedics.While death-associated protein kinase 2(DAPK2)is known to play roles in cellular apoptosis and autophagy,its specific contributions to the advancement of OPLL are not well understood.Methods:Ligament fibroblasts were harvested from patients diagnosed with OPLL.Techniques such as real-time reverse transcriptasepolymerase chain reaction(RT-qPCR)and Western blot analysis were employed to assess DAPK2 levels in both ligament tissues and cultured fibroblasts.The extent of osteogenic differentiation in these cells was evaluated using an alizarin red S(ARS)staining.Additionally,the expression of ossification markers and autophagy markers was quantified.The autophagic activity was further analyzed through LC3 immunofluorescence and transmission electron microscopy(TEM).An in vivo heterotopic bone formation assay was conducted in mice to assess the role of DAPK2 in ossification.Results:Elevated DAPK2 expression was confirmed in both OPLL patient tissues and derived fibroblasts,in contrast to non-OPLL controls.Silencing of DAPK2 significantly curtailed osteogenic differentiation and autophagy in these fibroblasts,evidenced by decreased levels of LC3,and Beclin1,and reduced autophagosome formation.Additionally,DAPK2 was found to inhibit the mechanistic target of the rapamycin complex 1(mTORC1)complex’s activity.In vivo studies demonstrated that DAPK2 facilitates ossification,and this effect could be counteracted by the mTORC1 inhibitor rapamycin.Conclusion:DAPK2 enhances autophagy and osteogenic processes in OPLL through modulation of the mTORC1 pathway.展开更多
Pancreatic cancer is one of the most aggressive cancers with a median survival time of less than 5 months,and conventional chemotherapeutics are the main treatment strategy.Poly(ADP-ribose)polymerase(PARP)inhibitors h...Pancreatic cancer is one of the most aggressive cancers with a median survival time of less than 5 months,and conventional chemotherapeutics are the main treatment strategy.Poly(ADP-ribose)polymerase(PARP)inhibitors have been recently approved for BRCA1/2-mutant pancreatic cancer,opening a new era for targeted therapy for this disease.However,most pancreatic cancer patients carry wild-type BRCA1/2 with resistance to PARP inhibitors.Here,we reported that mammalian target of rapamycin complex 2(mTORC2)kinase is overexpressed in pancreatic cancer tissues and promotes pancreatic cancer cell growth and invasion.Moreover,we found that knockdown of the mTORC2 obligate subunit Rictor sensitized pancreatic cancer cells to the PARP inhibitor olaparib.Mechanistically,we showed that mTORC2 positively regulates homologous recombination(HR)repair by modulating BRCA1 recruitment to DNA double-strand breaks(DSBs).In addition,we confirmed that combination treatment with the mTORC2 inhibitor PP242 and the PARP inhibitor olaparib synergistically inhibited pancreatic cancer growth in vivo.Thus,this study provides a novel target and strategy for optimizing PARP inhibitor efficiency in pancreatic cancers.展开更多
Heat shock proteins (HSPs) serve to correct proteins’ conformation, send the damaged proteins for degradation (quality control function). Heat shock factors (HSFs) are their transcription factors. The protein complex...Heat shock proteins (HSPs) serve to correct proteins’ conformation, send the damaged proteins for degradation (quality control function). Heat shock factors (HSFs) are their transcription factors. The protein complexes mTOR1 and 2 (with the same core mTOR), the phosphoinositide-dependent protein kinase-1 (PDK1), the seine/threonine-specific protein kinase (Akt), HSF1, plus their associated proteins form a network participating in protein synthesis, bio-energy generation, signaling for apoptosis with the help of HSPs. A cancer cell synthesizes proteins at fast rate and needs more HSPs to work on quality control. Shutting down this network would lead to cell death. Thus inhibitors of mTOR (mTORI) and inhibitors of HSPs (HSPI) could drive cancer cell to apoptosis—a “passive approach”. On the other hand, HSPs form complexes with polypeptides characteristic of the cancer cells;on excretion from the cell, they becomes antigens for the immunity cells, eventually leading to maturation of the cytotoxic T cells, forming the basic principle of preparing cancer-specific, person-specific vaccine. Recent finding shows that HSP70 can penetrate cancer cell and expel its analog to extracellular region, giving the hope to prepare a non-person-specific vaccine covering a variety of cancers. Activation of anti-cancer immunity is the “active approach”. On the other hand, mild hyperthermia, with increase of intracellular HSPs, has been found to activate the immunity response, and demonstrate anti-cancer effects. There are certain “mysteries” behind the mechanisms of the active and passive approaches. We analyze the mechanisms involved and provide explanations to some mysteries. We also suggest future research to improve our understanding of these two approaches, in which HSPs play many roles.展开更多
A complex network of factors contributes to neuroinflammation,such as infections,brain injuries and accumulation of toxic metabolites（Gendelman,2002）.Eicosanoids and several cytokines are the main mediators of infla...A complex network of factors contributes to neuroinflammation,such as infections,brain injuries and accumulation of toxic metabolites（Gendelman,2002）.Eicosanoids and several cytokines are the main mediators of inflammatory process;in fact,when an inflammatory condition persists,it can be responsible for the progression of degenerative diseases,展开更多
哺乳动物雷帕霉素靶蛋白复合体(mammalian target of rapamycin complex,mTORC)是细胞生长、存活、代谢的重要调控中心,它对维持生命有机体的正常生理活动和内稳态的平衡有着重要作用。mTORC根据其蛋白组份可分为mTORC1和mTORC2。mTORC...哺乳动物雷帕霉素靶蛋白复合体(mammalian target of rapamycin complex,mTORC)是细胞生长、存活、代谢的重要调控中心,它对维持生命有机体的正常生理活动和内稳态的平衡有着重要作用。mTORC根据其蛋白组份可分为mTORC1和mTORC2。mTORC2的主要组成蛋白有mTOR、Rictor、mLST8、Deptor、mSin1、Protor和Hsp70。mTORC2通过作用于Akt,PKCα和SGK1等来调控多项生命活动,如胚胎发育,细胞骨架重建,细胞迁移,蛋白质翻译和修饰等。mTOR信号通路异常已被证实与肿瘤相关,同时发现多种肿瘤发生与mTORC2及其异常调节信号通路相关。因此,对mTORC2组成、功能以及参与的信号通路的研究,可能为进一步研制其相关的靶向抑制药物乃至肿瘤治疗提供新思路。本综述将介绍mTORC2的组成结构、功能、参与的信号通路,及其在血液肿瘤中作用的研究进展。展开更多
Akt/mTOR/p70S6K1 signaling pathway plays an important role in the pathogenesis of cancer and diabetes.Macrophages and lymphocytes are involved in the pathogenesis of diabetes,diabetic atherosclerosis,formation of insu...Akt/mTOR/p70S6K1 signaling pathway plays an important role in the pathogenesis of cancer and diabetes.Macrophages and lymphocytes are involved in the pathogenesis of diabetes,diabetic atherosclerosis,formation of insulin resistance as well as immune response to cancer and tumor maintenance.The aim of the study was to determine the Akt activation by mTORC2 in peripheral blood mononuclear cell(PBMC)of patients with type 2 diabetes and cancer.The following groups were studied:control group,patients with type 2 diabetes,cancer patients and patients with both cancer and diabetes.The amounts of phospho-Akt(р-S473)and phospho-p70S6K1(p-T389)were determined using ELISA kits.The amount of phosphorylated Akt significantly increases in PBMC of patients with cancer.There was no effect in PBMC from patients with type 2 diabetes and significant decrease in the amount of phospho-Akt in PBMC of the patients group both with cancer and diabetes.p70S6K1 activation was observed in PBMC of the groups 2 and 3 patients.Thus,chronic diseases such as type 2 diabetes and cancer can affect the signaling mechanisms in blood cells.The state of Akt phosphorylation in leukocytes can indicate the activity of mTORC1 and its substrates,which may be important for the evaluation of the pathological process and the efficacy of the drugs.展开更多
Mammalian target of rapamycin （mTOR） plays essen- tial roles in cell proliferation, survival and metabolism by forming at least two functional distinct multi-protein complexes, mTORC1 and mTORC2. External growth sig...Mammalian target of rapamycin （mTOR） plays essen- tial roles in cell proliferation, survival and metabolism by forming at least two functional distinct multi-protein complexes, mTORC1 and mTORC2. External growth signals can be received and interpreted by mTORC2 and further transduced to mTORCI. On the other hand, mTORC1 can sense inner-cellular physiological cues such as amino acids and energy states and can indi- rectly suppress mTORC2 activity in part through phosphorylation of its upstream adaptors, IRS-1 or Grbl0, under insulin or IGF-1 stimulation conditions. To date, upstream signaling pathways governing mTORC1 activation have been studied extensively, while the mechanisms modulating mTORC2 activity remain largely elusive. We recently reported that Sin1, an essential mTORC2 subunit, was phosphorylated by either Akt or S6K in a cellular context-dependent manner. More importantly, phosphorylation of Sin1 at T86 and T398 led to a dissociation of Sin1 from the functional mTORC2 holo-enzyme, resulting in reduced Akt activity and sensitizing cells to various apoptotic challenges. Notably, an ovarian cancer patient-derived Sin1-R81T mutation abolished Sin1-T86 phosphoryla- tion by disrupting the canonical S6K-phoshorylation motif, thereby bypassing Sinl-phosphorylation-medi- ated suppression of mTORC2 and leading to sustained Akt signaling to promote tumorigenesis. Our work therefore provided physiological and pathological evi- dence to reveal the biological significance of Sin1 phosphorylation-mediated suppression of the mTOR/ Akt oncogenic signaling, and further suggested that misregulation of this process might contribute to Akt hyper-activation that is frequently observed in human cancers.展开更多
基金This research received funding from the Natural Science Foundation of Shanghai(Grant No.20ZR1457600)the School-Level Basic Medical Project of Naval Medical University(Grant No.2021MS13).
文摘Background:Ossification of the posterior longitudinal ligament(OPLL)is a prevalent condition in orthopedics.While death-associated protein kinase 2(DAPK2)is known to play roles in cellular apoptosis and autophagy,its specific contributions to the advancement of OPLL are not well understood.Methods:Ligament fibroblasts were harvested from patients diagnosed with OPLL.Techniques such as real-time reverse transcriptasepolymerase chain reaction(RT-qPCR)and Western blot analysis were employed to assess DAPK2 levels in both ligament tissues and cultured fibroblasts.The extent of osteogenic differentiation in these cells was evaluated using an alizarin red S(ARS)staining.Additionally,the expression of ossification markers and autophagy markers was quantified.The autophagic activity was further analyzed through LC3 immunofluorescence and transmission electron microscopy(TEM).An in vivo heterotopic bone formation assay was conducted in mice to assess the role of DAPK2 in ossification.Results:Elevated DAPK2 expression was confirmed in both OPLL patient tissues and derived fibroblasts,in contrast to non-OPLL controls.Silencing of DAPK2 significantly curtailed osteogenic differentiation and autophagy in these fibroblasts,evidenced by decreased levels of LC3,and Beclin1,and reduced autophagosome formation.Additionally,DAPK2 was found to inhibit the mechanistic target of the rapamycin complex 1(mTORC1)complex’s activity.In vivo studies demonstrated that DAPK2 facilitates ossification,and this effect could be counteracted by the mTORC1 inhibitor rapamycin.Conclusion:DAPK2 enhances autophagy and osteogenic processes in OPLL through modulation of the mTORC1 pathway.
基金This work was supported by the National Natural Science Foundation of China(81572408)the Program of Medical Innovation Team and Leading Medical Talents in Jiangsu Province(2017ZXKJQW09).
文摘Pancreatic cancer is one of the most aggressive cancers with a median survival time of less than 5 months,and conventional chemotherapeutics are the main treatment strategy.Poly(ADP-ribose)polymerase(PARP)inhibitors have been recently approved for BRCA1/2-mutant pancreatic cancer,opening a new era for targeted therapy for this disease.However,most pancreatic cancer patients carry wild-type BRCA1/2 with resistance to PARP inhibitors.Here,we reported that mammalian target of rapamycin complex 2(mTORC2)kinase is overexpressed in pancreatic cancer tissues and promotes pancreatic cancer cell growth and invasion.Moreover,we found that knockdown of the mTORC2 obligate subunit Rictor sensitized pancreatic cancer cells to the PARP inhibitor olaparib.Mechanistically,we showed that mTORC2 positively regulates homologous recombination(HR)repair by modulating BRCA1 recruitment to DNA double-strand breaks(DSBs).In addition,we confirmed that combination treatment with the mTORC2 inhibitor PP242 and the PARP inhibitor olaparib synergistically inhibited pancreatic cancer growth in vivo.Thus,this study provides a novel target and strategy for optimizing PARP inhibitor efficiency in pancreatic cancers.
文摘Heat shock proteins (HSPs) serve to correct proteins’ conformation, send the damaged proteins for degradation (quality control function). Heat shock factors (HSFs) are their transcription factors. The protein complexes mTOR1 and 2 (with the same core mTOR), the phosphoinositide-dependent protein kinase-1 (PDK1), the seine/threonine-specific protein kinase (Akt), HSF1, plus their associated proteins form a network participating in protein synthesis, bio-energy generation, signaling for apoptosis with the help of HSPs. A cancer cell synthesizes proteins at fast rate and needs more HSPs to work on quality control. Shutting down this network would lead to cell death. Thus inhibitors of mTOR (mTORI) and inhibitors of HSPs (HSPI) could drive cancer cell to apoptosis—a “passive approach”. On the other hand, HSPs form complexes with polypeptides characteristic of the cancer cells;on excretion from the cell, they becomes antigens for the immunity cells, eventually leading to maturation of the cytotoxic T cells, forming the basic principle of preparing cancer-specific, person-specific vaccine. Recent finding shows that HSP70 can penetrate cancer cell and expel its analog to extracellular region, giving the hope to prepare a non-person-specific vaccine covering a variety of cancers. Activation of anti-cancer immunity is the “active approach”. On the other hand, mild hyperthermia, with increase of intracellular HSPs, has been found to activate the immunity response, and demonstrate anti-cancer effects. There are certain “mysteries” behind the mechanisms of the active and passive approaches. We analyze the mechanisms involved and provide explanations to some mysteries. We also suggest future research to improve our understanding of these two approaches, in which HSPs play many roles.
文摘A complex network of factors contributes to neuroinflammation,such as infections,brain injuries and accumulation of toxic metabolites（Gendelman,2002）.Eicosanoids and several cytokines are the main mediators of inflammatory process;in fact,when an inflammatory condition persists,it can be responsible for the progression of degenerative diseases,
文摘哺乳动物雷帕霉素靶蛋白复合体(mammalian target of rapamycin complex,mTORC)是细胞生长、存活、代谢的重要调控中心,它对维持生命有机体的正常生理活动和内稳态的平衡有着重要作用。mTORC根据其蛋白组份可分为mTORC1和mTORC2。mTORC2的主要组成蛋白有mTOR、Rictor、mLST8、Deptor、mSin1、Protor和Hsp70。mTORC2通过作用于Akt,PKCα和SGK1等来调控多项生命活动,如胚胎发育,细胞骨架重建,细胞迁移,蛋白质翻译和修饰等。mTOR信号通路异常已被证实与肿瘤相关,同时发现多种肿瘤发生与mTORC2及其异常调节信号通路相关。因此,对mTORC2组成、功能以及参与的信号通路的研究,可能为进一步研制其相关的靶向抑制药物乃至肿瘤治疗提供新思路。本综述将介绍mTORC2的组成结构、功能、参与的信号通路,及其在血液肿瘤中作用的研究进展。
文摘Akt/mTOR/p70S6K1 signaling pathway plays an important role in the pathogenesis of cancer and diabetes.Macrophages and lymphocytes are involved in the pathogenesis of diabetes,diabetic atherosclerosis,formation of insulin resistance as well as immune response to cancer and tumor maintenance.The aim of the study was to determine the Akt activation by mTORC2 in peripheral blood mononuclear cell(PBMC)of patients with type 2 diabetes and cancer.The following groups were studied:control group,patients with type 2 diabetes,cancer patients and patients with both cancer and diabetes.The amounts of phospho-Akt(р-S473)and phospho-p70S6K1(p-T389)were determined using ELISA kits.The amount of phosphorylated Akt significantly increases in PBMC of patients with cancer.There was no effect in PBMC from patients with type 2 diabetes and significant decrease in the amount of phospho-Akt in PBMC of the patients group both with cancer and diabetes.p70S6K1 activation was observed in PBMC of the groups 2 and 3 patients.Thus,chronic diseases such as type 2 diabetes and cancer can affect the signaling mechanisms in blood cells.The state of Akt phosphorylation in leukocytes can indicate the activity of mTORC1 and its substrates,which may be important for the evaluation of the pathological process and the efficacy of the drugs.
文摘Mammalian target of rapamycin （mTOR） plays essen- tial roles in cell proliferation, survival and metabolism by forming at least two functional distinct multi-protein complexes, mTORC1 and mTORC2. External growth signals can be received and interpreted by mTORC2 and further transduced to mTORCI. On the other hand, mTORC1 can sense inner-cellular physiological cues such as amino acids and energy states and can indi- rectly suppress mTORC2 activity in part through phosphorylation of its upstream adaptors, IRS-1 or Grbl0, under insulin or IGF-1 stimulation conditions. To date, upstream signaling pathways governing mTORC1 activation have been studied extensively, while the mechanisms modulating mTORC2 activity remain largely elusive. We recently reported that Sin1, an essential mTORC2 subunit, was phosphorylated by either Akt or S6K in a cellular context-dependent manner. More importantly, phosphorylation of Sin1 at T86 and T398 led to a dissociation of Sin1 from the functional mTORC2 holo-enzyme, resulting in reduced Akt activity and sensitizing cells to various apoptotic challenges. Notably, an ovarian cancer patient-derived Sin1-R81T mutation abolished Sin1-T86 phosphoryla- tion by disrupting the canonical S6K-phoshorylation motif, thereby bypassing Sinl-phosphorylation-medi- ated suppression of mTORC2 and leading to sustained Akt signaling to promote tumorigenesis. Our work therefore provided physiological and pathological evi- dence to reveal the biological significance of Sin1 phosphorylation-mediated suppression of the mTOR/ Akt oncogenic signaling, and further suggested that misregulation of this process might contribute to Akt hyper-activation that is frequently observed in human cancers.
