Objective:RECQL4(a member of the RECQ helicase family)upregulation has been reported to be associated with tumor progression in several malignancies.However,whether RECQL4 sustains esophageal squamous cell carcinoma(E...Objective:RECQL4(a member of the RECQ helicase family)upregulation has been reported to be associated with tumor progression in several malignancies.However,whether RECQL4 sustains esophageal squamous cell carcinoma(ESCC)has not been elucidated.In this study,we determined the functional role for RECQL4 in ESCC progression.Methods:RECQL4 expression in clinical samples of ESCC was examined by immunohistochemistry.Cell proliferation,cellular senescence,the epithelial-mesenchymal transition(EMT),DNA damage,and reactive oxygen species in ESCC cell lines with RECQL4 depletion or overexpression were analyzed.The levels of proteins involved in the DNA damage response(DDR),cell cycle progression,survival,and the EMT were determined by Western blot analyses.Results:RECQL4 was highly expressed in tumor tissues when compared to adjacent non-tumor tissues in ESCC(P<0.001)and positively correlated with poor differentiation(P=0.011),enhanced invasion(P=0.033),and metastasis(P=0.048).RECQL4 was positively associated with proliferation and migration in ESCC cells.Depletion of RECQL4 also inhibited growth of tumor xenografts in vivo.RECQL4 depletion induced G0/G1 phase arrest and cellular senescence.Importantly,the levels of DNA damage and reactive oxygen species were increased when RECQL4 was depleted.DDR,as measured by the activation of ATM,ATR,CHK1,and CHK2,was impaired.RECQL4 was also shown to promote the activation of AKT,ERK,and NF-k B in ESCC cells.Conclusions:The results indicated that RECQL4 was highly expressed in ESCC and played critical roles in the regulation of DDR,redox homeostasis,and cell survival.展开更多
Rothmund-Thomson syndrome(RTS)is a rare autosomal-recessive disorder with clinical features consisting of rash,poikiloderma,sparse hair,short stature,juvenile cataracts,skeletal abnormalities,and cancer predisposition...Rothmund-Thomson syndrome(RTS)is a rare autosomal-recessive disorder with clinical features consisting of rash,poikiloderma,sparse hair,short stature,juvenile cataracts,skeletal abnormalities,and cancer predisposition.Genetic studies involving detection of pathogenic RECQL4 variants provide the diagnostic certitude.Osteosarcoma was found in two-thirds RECQL4-mutated RTS patients,while hematological malignancies were rarely reported.The variant diversity of RECQL4 gene has not been fully identified and mutations associated with hematologic malignancies are not well described.In this study,we presented a pedigree of RTS from a Chinese family,among which the proband was diagnosed with de novo myelodysplastic syndrome(MDS).Comprehensive medical examination and chromosome karyotyping were performed on the proband.Whole exome sequencing(WES)was performed on the proband,his sister and his mother.The familial cosegregation of sequence variants derived from WES was conducted by polymerase chain reaction–based Sanger sequencing.Structures of candidate RECQL4 mutants were done by in silico analysis to assess pathogenicity.Three novel RECQL4 germline variants,including c.T274C,c.G3014A,and c.G801C,were identified by WES and validated by Sanger sequencing.Prediction of conformation indicated that the structural stability of human RECQL4 protein was largely affected with these variants.The co-occurring U2AF1 p.S34F and TP53 p.Y220C mutations might contribute to the development of MDS.Our study expands the mutational spectrum of RECQL4 and provides underlying molecular mechanism for the development of MDS in RTS patients.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.81572785,31771260,and 81201750)a Ministry of Science and Technology(Grant No.2011CB966200)+2 种基金the Excellent Young and Mid-Career Scientist Award of Shandong Province(Grant No.BS2013YY023)the Key Research Project of Shandong Province(Grant No.2016GSF201072)the Project of State Key Laboratory of Radiation Medicine and Protection,Soochow University(Grant No.GZN1201804)。
文摘Objective:RECQL4(a member of the RECQ helicase family)upregulation has been reported to be associated with tumor progression in several malignancies.However,whether RECQL4 sustains esophageal squamous cell carcinoma(ESCC)has not been elucidated.In this study,we determined the functional role for RECQL4 in ESCC progression.Methods:RECQL4 expression in clinical samples of ESCC was examined by immunohistochemistry.Cell proliferation,cellular senescence,the epithelial-mesenchymal transition(EMT),DNA damage,and reactive oxygen species in ESCC cell lines with RECQL4 depletion or overexpression were analyzed.The levels of proteins involved in the DNA damage response(DDR),cell cycle progression,survival,and the EMT were determined by Western blot analyses.Results:RECQL4 was highly expressed in tumor tissues when compared to adjacent non-tumor tissues in ESCC(P<0.001)and positively correlated with poor differentiation(P=0.011),enhanced invasion(P=0.033),and metastasis(P=0.048).RECQL4 was positively associated with proliferation and migration in ESCC cells.Depletion of RECQL4 also inhibited growth of tumor xenografts in vivo.RECQL4 depletion induced G0/G1 phase arrest and cellular senescence.Importantly,the levels of DNA damage and reactive oxygen species were increased when RECQL4 was depleted.DDR,as measured by the activation of ATM,ATR,CHK1,and CHK2,was impaired.RECQL4 was also shown to promote the activation of AKT,ERK,and NF-k B in ESCC cells.Conclusions:The results indicated that RECQL4 was highly expressed in ESCC and played critical roles in the regulation of DDR,redox homeostasis,and cell survival.
基金National Natural Science Foundation of China(grant numbers 81770106,82170206).
文摘Rothmund-Thomson syndrome(RTS)is a rare autosomal-recessive disorder with clinical features consisting of rash,poikiloderma,sparse hair,short stature,juvenile cataracts,skeletal abnormalities,and cancer predisposition.Genetic studies involving detection of pathogenic RECQL4 variants provide the diagnostic certitude.Osteosarcoma was found in two-thirds RECQL4-mutated RTS patients,while hematological malignancies were rarely reported.The variant diversity of RECQL4 gene has not been fully identified and mutations associated with hematologic malignancies are not well described.In this study,we presented a pedigree of RTS from a Chinese family,among which the proband was diagnosed with de novo myelodysplastic syndrome(MDS).Comprehensive medical examination and chromosome karyotyping were performed on the proband.Whole exome sequencing(WES)was performed on the proband,his sister and his mother.The familial cosegregation of sequence variants derived from WES was conducted by polymerase chain reaction–based Sanger sequencing.Structures of candidate RECQL4 mutants were done by in silico analysis to assess pathogenicity.Three novel RECQL4 germline variants,including c.T274C,c.G3014A,and c.G801C,were identified by WES and validated by Sanger sequencing.Prediction of conformation indicated that the structural stability of human RECQL4 protein was largely affected with these variants.The co-occurring U2AF1 p.S34F and TP53 p.Y220C mutations might contribute to the development of MDS.Our study expands the mutational spectrum of RECQL4 and provides underlying molecular mechanism for the development of MDS in RTS patients.
