Background:Metastasis is the leading cause of cancer-related mortality,with circulating tumor cell(CTC)clusters serving as highly efficient precursors of distant metastasis.Survival of CTC clusters in the bloodstream ...Background:Metastasis is the leading cause of cancer-related mortality,with circulating tumor cell(CTC)clusters serving as highly efficient precursors of distant metastasis.Survival of CTC clusters in the bloodstream is the primary contributor to tumor metastasis.However,the underlying mechanisms of how CTC clusters respond to the blood environment and drive metastasis remain elusive.This study aimed to elucidate the potential mechanisms that enable CTC clusters to adapt and survive in the bloodstream.Methods:CTC clusters were detected using a microfluidic system in cancer patients,as well as in patient-derived xenograft(PDX),cell line-derived xenograft,and syngeneic models.The key molecules responsible for the adaptive survival of CTC clusters were characterized using RNA-sequencing(RNAseq),gene interference,and flow cytometry.To investigate the underlying mechanisms of adaptive survival,RNA-seq,targeted metabolomics,isotope tracing experiments,chromatin immunoprecipitation(ChIP)sequencing,and immunofluorescence(IF)staining were employed.The therapeutic potential of survival pathway inhibitor combined with chemotherapy drug was evaluated in patient-derived CTCs and the PDX model.Results:CTC clusters exhibited superior survival and metastatic capacity compared to single CTCs and were associated with adverse clinical outcomes.The unfolded protein response mediator protein kinase R-like endoplasmic reticulum kinase(PERK)was activated in CTC clusters and maintained Sadenosylmethionine(SAM)availability,facilitating their adaptive survival in the bloodstream.Mechanistically,PERK mediated the upregulation of activating transcription factor 4(ATF4),which enhanced methionine adenosyltransferase 2A(MAT2A)expression,contributing to SAM synthesis.Increased SAM enhanced H3K4me3 modification of the platelet-derived growth factor B(PDGFB)promoter,leading to elevated PDGFB secretion and its accumulation in the intercellular region within CTC clusters.PDGFB functioned as a shared survival signal,triggering the phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)pathway via platelet-derived growth factor receptor beta(PDGFRβ),supporting CTC cluster survival in the bloodstream.Inhibition of PERK and PDGFRβprofoundly impaired the survival signaling and suppressed the metastatic dissemination of CTC clusters.Conclusions:Our findings revealed a PERK/MAT2A/PDGFB axis that confers adaptive survival capabilities to CTC clusters in the bloodstream.Targeting this survival signaling pathway represents a promising therapeutic strategy for metastatic cancer.展开更多
Background:Tumor metastasis is a major threat to cancer patient survival.The organ-specific niche plays a pivotal role in tumor organotropic metas-tasis.Fibroblasts serve as a vital component of the metastatic microen...Background:Tumor metastasis is a major threat to cancer patient survival.The organ-specific niche plays a pivotal role in tumor organotropic metas-tasis.Fibroblasts serve as a vital component of the metastatic microenviron-ment,but how heterogeneous metastasis-associated fibroblasts(MAFs)promote organotropic metastasis is poorly characterized.Here,we aimed to decipher the heterogeneity of MAFs and elucidate the distinct roles of these fibroblasts in pulmonary metastasis formation in breast cancer.Methods:Mouse models of breast cancer pulmonary metastasis were estab-lished using an in vivo selection method of repeated injections of metastatic cells purified from the mouse lung.Single-cell RNA-sequencing(scRNA-seq)was employed to investigate the heterogeneity of MAFs.Transgenic mice were used to examine the contribution of tryptophan 2,3-dioxygenase-positive matrix fibroblasts(TDO2^(+)MFs)in lung metastasis.Results:We uncovered 3 subtypes of MAFs in the lung metastatic microenviron-ment,and their transcriptome profiles changed dynamically as lung metastasis evolved.As the predominant subtype,MFs were exclusively marked by platelet-derived growth factor receptor alpha(PDGFRA)and mainly located on the edge of the metastasis,and T cells were enriched around MFs.Notably,high MF sig-natures were significantly associated with poor survival in breast cancer patients.Lung metastases were markedly diminished,and the suppression of T cells was dramatically attenuated in MF-depleted experimental metastatic mouse mod-els.We found that TDO2^(+)MFs controlled pulmonary metastasis by producing kynurenine(KYN),which upregulated ferritin heavy chain 1(FTH1)level in dis-seminated tumor cells(DTCs),enabling DTCs to resist ferroptosis.Moreover,TDO2^(+)MF-secreted chemokines C-C motif chemokine ligand 8(CCL8)and C-C motif chemokine ligand 11(CCL11)recruited T cells.TDO2^(+)MF-derived KYN induced T cell dysfunction.Conditional knockout of Tdo2 in MFs diminished lung metastasis and enhanced immune activation.Conclusions:Our study reveals crucial roles of TDO2^(+)MFs in promoting lung metastasis and DTCs’immune evasion in the metastatic niche.It suggests that targeting the metabolism of lung-specific stromal cells may be an effective treatment strategy for breast cancer patients with lung metastasis.展开更多
In order to disclose the relationship between mutations of mitochondrial DNA (mtDNA) and gastric car-cinogenesis, we screened the entire mtDNA sequence in 30 cases of human gastric cancer and matched normal tissues by...In order to disclose the relationship between mutations of mitochondrial DNA (mtDNA) and gastric car-cinogenesis, we screened the entire mtDNA sequence in 30 cases of human gastric cancer and matched normal tissues by using denaturing high-performance liquid chromatogra-phy (DHPLC) and DNA sequencing. Our data showed that high frequency (66.7%, 20/30) of mitochondrial genome mutation occurred in gastric cancer. Among these variants, 17 cases (56.7%, 17/30) were identified to be somatic mutation. High level mutant frequency was found in ND4, ND5 coding genes and D-loop control region, which was 36.7%, 26.7% and 30% respectively. Comparing with complexes Ⅲ, Ⅳ and V of the electron transport chain, we found that variants appeared to be more frequent in the subunit genes of complex I. Most of mutations were base substitutions (85.4%, 41/48). Our results suggested that mutations of subunit genes encoding complex I, especially MM, ND4 and ND5 genes, might contribute to human gastric carcinogenesis.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:NSFC 82072938,NSFC82173155,NSFC82372823the Senior Medical Talents Program of Chongqing Medical University for Young and Middle-aged Scientist,Grant/Award Number:2021-W0068+1 种基金the Outstanding Professorship Program of Chongqing Medical University,Grant/Award Number:R10005the Outstanding Postgraduate Fund of Chongqing Medical University,Grant/Award Number:BJRC202313。
文摘Background:Metastasis is the leading cause of cancer-related mortality,with circulating tumor cell(CTC)clusters serving as highly efficient precursors of distant metastasis.Survival of CTC clusters in the bloodstream is the primary contributor to tumor metastasis.However,the underlying mechanisms of how CTC clusters respond to the blood environment and drive metastasis remain elusive.This study aimed to elucidate the potential mechanisms that enable CTC clusters to adapt and survive in the bloodstream.Methods:CTC clusters were detected using a microfluidic system in cancer patients,as well as in patient-derived xenograft(PDX),cell line-derived xenograft,and syngeneic models.The key molecules responsible for the adaptive survival of CTC clusters were characterized using RNA-sequencing(RNAseq),gene interference,and flow cytometry.To investigate the underlying mechanisms of adaptive survival,RNA-seq,targeted metabolomics,isotope tracing experiments,chromatin immunoprecipitation(ChIP)sequencing,and immunofluorescence(IF)staining were employed.The therapeutic potential of survival pathway inhibitor combined with chemotherapy drug was evaluated in patient-derived CTCs and the PDX model.Results:CTC clusters exhibited superior survival and metastatic capacity compared to single CTCs and were associated with adverse clinical outcomes.The unfolded protein response mediator protein kinase R-like endoplasmic reticulum kinase(PERK)was activated in CTC clusters and maintained Sadenosylmethionine(SAM)availability,facilitating their adaptive survival in the bloodstream.Mechanistically,PERK mediated the upregulation of activating transcription factor 4(ATF4),which enhanced methionine adenosyltransferase 2A(MAT2A)expression,contributing to SAM synthesis.Increased SAM enhanced H3K4me3 modification of the platelet-derived growth factor B(PDGFB)promoter,leading to elevated PDGFB secretion and its accumulation in the intercellular region within CTC clusters.PDGFB functioned as a shared survival signal,triggering the phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)pathway via platelet-derived growth factor receptor beta(PDGFRβ),supporting CTC cluster survival in the bloodstream.Inhibition of PERK and PDGFRβprofoundly impaired the survival signaling and suppressed the metastatic dissemination of CTC clusters.Conclusions:Our findings revealed a PERK/MAT2A/PDGFB axis that confers adaptive survival capabilities to CTC clusters in the bloodstream.Targeting this survival signaling pathway represents a promising therapeutic strategy for metastatic cancer.
基金supported by National Key Projects of Ministry of Science and Technology of China(MOST 2018YFE0113700)National Natural Science Foundation of China(NSFC82173155,NSFC81874199)+2 种基金the Outstanding Professorship Program of Chongqing Medical University(2019-R10005)to Manran Liusupported by the Outstanding Postgraduate Fund of Chongqing Medical University(BJRC202021,BJRC202025)the Chongqing Graduate Research and Innovation Project of the Chongqing Education Committee(CYB22218)for Shanchun Chen.
文摘Background:Tumor metastasis is a major threat to cancer patient survival.The organ-specific niche plays a pivotal role in tumor organotropic metas-tasis.Fibroblasts serve as a vital component of the metastatic microenviron-ment,but how heterogeneous metastasis-associated fibroblasts(MAFs)promote organotropic metastasis is poorly characterized.Here,we aimed to decipher the heterogeneity of MAFs and elucidate the distinct roles of these fibroblasts in pulmonary metastasis formation in breast cancer.Methods:Mouse models of breast cancer pulmonary metastasis were estab-lished using an in vivo selection method of repeated injections of metastatic cells purified from the mouse lung.Single-cell RNA-sequencing(scRNA-seq)was employed to investigate the heterogeneity of MAFs.Transgenic mice were used to examine the contribution of tryptophan 2,3-dioxygenase-positive matrix fibroblasts(TDO2^(+)MFs)in lung metastasis.Results:We uncovered 3 subtypes of MAFs in the lung metastatic microenviron-ment,and their transcriptome profiles changed dynamically as lung metastasis evolved.As the predominant subtype,MFs were exclusively marked by platelet-derived growth factor receptor alpha(PDGFRA)and mainly located on the edge of the metastasis,and T cells were enriched around MFs.Notably,high MF sig-natures were significantly associated with poor survival in breast cancer patients.Lung metastases were markedly diminished,and the suppression of T cells was dramatically attenuated in MF-depleted experimental metastatic mouse mod-els.We found that TDO2^(+)MFs controlled pulmonary metastasis by producing kynurenine(KYN),which upregulated ferritin heavy chain 1(FTH1)level in dis-seminated tumor cells(DTCs),enabling DTCs to resist ferroptosis.Moreover,TDO2^(+)MF-secreted chemokines C-C motif chemokine ligand 8(CCL8)and C-C motif chemokine ligand 11(CCL11)recruited T cells.TDO2^(+)MF-derived KYN induced T cell dysfunction.Conditional knockout of Tdo2 in MFs diminished lung metastasis and enhanced immune activation.Conclusions:Our study reveals crucial roles of TDO2^(+)MFs in promoting lung metastasis and DTCs’immune evasion in the metastatic niche.It suggests that targeting the metabolism of lung-specific stromal cells may be an effective treatment strategy for breast cancer patients with lung metastasis.
基金This work was supported by theNational Key Basic Science Research Program (Grant No. G1998051203)the National Natural Science Foundation of China (Grant No. 39602526).
文摘In order to disclose the relationship between mutations of mitochondrial DNA (mtDNA) and gastric car-cinogenesis, we screened the entire mtDNA sequence in 30 cases of human gastric cancer and matched normal tissues by using denaturing high-performance liquid chromatogra-phy (DHPLC) and DNA sequencing. Our data showed that high frequency (66.7%, 20/30) of mitochondrial genome mutation occurred in gastric cancer. Among these variants, 17 cases (56.7%, 17/30) were identified to be somatic mutation. High level mutant frequency was found in ND4, ND5 coding genes and D-loop control region, which was 36.7%, 26.7% and 30% respectively. Comparing with complexes Ⅲ, Ⅳ and V of the electron transport chain, we found that variants appeared to be more frequent in the subunit genes of complex I. Most of mutations were base substitutions (85.4%, 41/48). Our results suggested that mutations of subunit genes encoding complex I, especially MM, ND4 and ND5 genes, might contribute to human gastric carcinogenesis.
