The deubiquitylase UCHL3 maintains cancer stem-like properties by stabilizing the aryl hydrocarbon receptor

Cancer stem cells(CSCs)exhibit highly aggressive and metastatic features and resistance to chemotherapy and radiotherapy.Aryl hydrocarbon receptor(AhR)expression varies among non-small cell lung cancers(NSCLCs),and the mechanisms that support abnormal AhR expression in CSCs remain elusive.Here,we identified ubiquitin carboxyl terminal hydrolase L3(UCHL3),a DUB enzyme in the UCH protease family,as a bona fide deubiquitylase of the AhR in NSCLC.UCHL3 was shown to interact with,deubiquitylate,and stabilize AhR in a manner dependent on its deubiquitylation activity.Moreover,we showed that UCHL3 promotes the stem-like characteristics and potent tumorigenic capacity of NSCLC cells.UCHL3 increased AhR stability and the binding of AhR to the promoter regions of the“stemness”genes ATP-binding cassette subfamily G member 2(ABCG2),KLF4,and c-Myc.Depletion of UCHL3 markedly downregulated the“stemness”genes ABCG2,KLF4,and c-Myc,leading to the loss of selfrenewal and tumorigenesis in NSCLCs.Furthermore,the UCHL3 inhibitor TCID induced AhR degradation and exhibited significantly attenuated efficacy in NSCLC cells with stem cell-like properties.Additionally,UCHL3 was shown to indicate poor prognosis in patients with lung adenocarcinoma.In general,our results reveal that the UCHL3 deubiquitylase is pivotal for AhR protein stability and a potential target for NSCLC-targeted therapy.

The cross-talk between methylation and phosphorylation in lymphoid-specific helicase drives cancer stem-like properties

Posttranslational modifications(PTMs)of proteins,including chromatin modifiers,play crucial roles in the dynamic alteration of various protein properties and functions including stem-cell properties.However,the roles of Lymphoid-specific helicase(LSH),a DNA methylation modifier,in modulating stem-like properties in cancer are still not clearly clarified.Therefore,exploring PTMs modulation of LSH activity will be of great significance to further understand the function and activity of LSH.Here,we demonstrate that LSH is capable to undergo PTMs,including methylation and phosphorylation.The arginine methyltransferase PRMT5 can methylate LSH at R309 residue,meanwhile,LSH could as well be phosphorylated by MAPK1 kinase at S503 residue.We further show that the accumulation of phosphorylation of LSH at S503 site exhibits downregulation of LSH methylation at R309 residue,which eventually promoting stem-like properties in lung cancer.Whereas,phosphorylation-deficient LSH S503A mutant promotes the accumulation of LSH methylation at R309 residue and attenuates stem-like properties,indicating the critical roles of LSH PTMs in modulating stem-like properties.Thus,our study highlights the importance of the crosstalk between LSH PTMs in determining its activity and function in lung cancer stem-cell maintenance.