BACKGROUND Hepatocellular carcinoma(HCC)remains a lethal malignancy due to its molecular complexity and chemoresistance.Rac family small GTPase 3(RAC3),a tumorigenic GTPase understudied in HCC,drives recurrence via E2...BACKGROUND Hepatocellular carcinoma(HCC)remains a lethal malignancy due to its molecular complexity and chemoresistance.Rac family small GTPase 3(RAC3),a tumorigenic GTPase understudied in HCC,drives recurrence via E2F transcription factor 1(E2F1)-mediated transcriptional activation.This study integrates multiomics and clustered regularly interspaced short palindromic repeats(CRISPR)screening to delineate RAC3’s roles.RAC3 overexpression correlates with advanced HCC and patient age,while its knockout suppresses proliferation.Mechanistically,RAC3 dysregulates cell-cycle checkpoints through E2F1 binding.Pharmacological RAC3 inhibition disrupts tumor growth and synergizes with chemotherapy to overcome resistance.AIM To explore RAC3’s expression,clinical links,and HCC mechanisms via multiomics and functional genomics.METHODS Multiomic integration of The Cancer Genome Atlas(TCGA),Gene Expression Omnibus,and Genotype-Tissue Expression datasets was performed to analyze RAC3 mRNA expression.Immunohistochemistry quantified RAC3 protein in 108 HCC/adjacent tissue pairs.Kaplan–Meier/Cox regression assessed prognostic significance using TCGA data.CRISPR screening validated RAC3’s necessity for HCC proliferation.Functional enrichment identified associated pathways;hTFtarget/JASPAR predicted transcription factors,validated via chromatin immunoprecipitation sequencing(ChIP-seq).RESULTS RAC3 exhibited significant mRNA and protein overexpression in HCC tissues,which was correlated with advanced tumor stages and reduced overall survival rates(hazard ratio=1.82,95%CI:1.31–2.53).Genetic ablation of RAC3 suppressed HCC cell proliferation across 16 cell lines.Pathway analysis revealed RAC3’s predominant involvement in cell-cycle regulation,DNA replication,and nucleocytoplasmic transport.Mechanistic investigations identified E2F1 as a pivotal upstream transcriptional regulator,and ChIP-seq analysis validated its direct binding to the RAC3 promoter region.These findings suggest that RAC3 drives HCC progression through E2F1-mediated cell-cycle dysregulation.CONCLUSION This study identified RAC3 as a key HCC oncogenic driver;its overexpression links to poor prognosis/resistance.Targeting the RAC3/E2F1 axis offers a new therapy,which highlights RAC3 as a biomarker/target.展开更多
Excessive activation of G-protein coupled receptor (GPCR) and receptor tyrosine kinase (RTK) pathways has been linked to prostate cancer metastasis. Rac activation
Metastasis is one of the main reasons causing death in cancer patients.It was reported that chemotherapy might induce metastasis.In order to uncover the mechanism of chemotherapy-induced metastasis and find solutions ...Metastasis is one of the main reasons causing death in cancer patients.It was reported that chemotherapy might induce metastasis.In order to uncover the mechanism of chemotherapy-induced metastasis and find solutions to inhibit treatment-induced metastasis,the relationship between epithelial-mesenchymal transition(EMT)and doxorubicin(DOX)treatment was investigated and a redox-sensitive small interfering RNA(siRNA)delivery system was designed.DOX-related reactive oxygen species(ROS)were found to be responsible for the invasiveness of tumor cells in vitro,causing enhanced EMT and cytoskeleton reconstruction regulated by Ras-related C3 botulinum toxin substrate 1(RAC1).In order to decrease RAC1,a redox-sensitive glycolipid drug delivery system(chitosan-ss-stearylamine conjugate(CSO-ss-SA))was designed to carry siRNA,forming a gene delivery system(CSO-ss-SA/siRNA)downregulating RAC1.CSO-ss-SA/siRNA exhibited an enhanced redox sensitivity compared to nonresponsive complexes in 10 mmol/L glutathione(GSH)and showed a significant safety.CSO-ss-SA/siRNA could effectively transmit siRNA into tumor cells,reducing the expression of RAC1 protein by 38.2%and decreasing the number of tumor-induced invasion cells by 42.5%.When combined with DOX,CSO-ss-SA/siRNA remarkably inhibited the chemotherapy-induced EMT in vivo and enhanced therapeutic efficiency.The present study indicates that RAC1 protein is a key regulator of chemotherapy-induced EMT and CSO-ss-SA/siRNA silencing RAC1 could efficiently decrease the tumor metastasis risk after chemotherapy.展开更多
Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, w...Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.展开更多
基金Supported by National Natural Science Foundation of China,No.82260581.
文摘BACKGROUND Hepatocellular carcinoma(HCC)remains a lethal malignancy due to its molecular complexity and chemoresistance.Rac family small GTPase 3(RAC3),a tumorigenic GTPase understudied in HCC,drives recurrence via E2F transcription factor 1(E2F1)-mediated transcriptional activation.This study integrates multiomics and clustered regularly interspaced short palindromic repeats(CRISPR)screening to delineate RAC3’s roles.RAC3 overexpression correlates with advanced HCC and patient age,while its knockout suppresses proliferation.Mechanistically,RAC3 dysregulates cell-cycle checkpoints through E2F1 binding.Pharmacological RAC3 inhibition disrupts tumor growth and synergizes with chemotherapy to overcome resistance.AIM To explore RAC3’s expression,clinical links,and HCC mechanisms via multiomics and functional genomics.METHODS Multiomic integration of The Cancer Genome Atlas(TCGA),Gene Expression Omnibus,and Genotype-Tissue Expression datasets was performed to analyze RAC3 mRNA expression.Immunohistochemistry quantified RAC3 protein in 108 HCC/adjacent tissue pairs.Kaplan–Meier/Cox regression assessed prognostic significance using TCGA data.CRISPR screening validated RAC3’s necessity for HCC proliferation.Functional enrichment identified associated pathways;hTFtarget/JASPAR predicted transcription factors,validated via chromatin immunoprecipitation sequencing(ChIP-seq).RESULTS RAC3 exhibited significant mRNA and protein overexpression in HCC tissues,which was correlated with advanced tumor stages and reduced overall survival rates(hazard ratio=1.82,95%CI:1.31–2.53).Genetic ablation of RAC3 suppressed HCC cell proliferation across 16 cell lines.Pathway analysis revealed RAC3’s predominant involvement in cell-cycle regulation,DNA replication,and nucleocytoplasmic transport.Mechanistic investigations identified E2F1 as a pivotal upstream transcriptional regulator,and ChIP-seq analysis validated its direct binding to the RAC3 promoter region.These findings suggest that RAC3 drives HCC progression through E2F1-mediated cell-cycle dysregulation.CONCLUSION This study identified RAC3 as a key HCC oncogenic driver;its overexpression links to poor prognosis/resistance.Targeting the RAC3/E2F1 axis offers a new therapy,which highlights RAC3 as a biomarker/target.
文摘Excessive activation of G-protein coupled receptor (GPCR) and receptor tyrosine kinase (RTK) pathways has been linked to prostate cancer metastasis. Rac activation
基金Project supported by the National Natural Science Foundation of China(No.81773648)the Zhejiang Provincial Natural Science Foundation of China(No.D19H30001)the Chinese Postdoc Funding(No.2018M630686).
文摘Metastasis is one of the main reasons causing death in cancer patients.It was reported that chemotherapy might induce metastasis.In order to uncover the mechanism of chemotherapy-induced metastasis and find solutions to inhibit treatment-induced metastasis,the relationship between epithelial-mesenchymal transition(EMT)and doxorubicin(DOX)treatment was investigated and a redox-sensitive small interfering RNA(siRNA)delivery system was designed.DOX-related reactive oxygen species(ROS)were found to be responsible for the invasiveness of tumor cells in vitro,causing enhanced EMT and cytoskeleton reconstruction regulated by Ras-related C3 botulinum toxin substrate 1(RAC1).In order to decrease RAC1,a redox-sensitive glycolipid drug delivery system(chitosan-ss-stearylamine conjugate(CSO-ss-SA))was designed to carry siRNA,forming a gene delivery system(CSO-ss-SA/siRNA)downregulating RAC1.CSO-ss-SA/siRNA exhibited an enhanced redox sensitivity compared to nonresponsive complexes in 10 mmol/L glutathione(GSH)and showed a significant safety.CSO-ss-SA/siRNA could effectively transmit siRNA into tumor cells,reducing the expression of RAC1 protein by 38.2%and decreasing the number of tumor-induced invasion cells by 42.5%.When combined with DOX,CSO-ss-SA/siRNA remarkably inhibited the chemotherapy-induced EMT in vivo and enhanced therapeutic efficiency.The present study indicates that RAC1 protein is a key regulator of chemotherapy-induced EMT and CSO-ss-SA/siRNA silencing RAC1 could efficiently decrease the tumor metastasis risk after chemotherapy.
基金supported by grants from the National Natural Science Foundation of China (No. 30872926)the Program for AdvancedTalents within Six Industries of Jiangsu Province (08-D) to Dr. Luo Gu+1 种基金the Science Development Foundation of Nanjing Medical University (No. 2010NJMUZ35)the Research Program funded by Schoolof Basic Medical Science, Nanjing Medical University to Dr. Jun Du
文摘Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.
