Functional Role Of SHQ1 In RNA Splicing Regulation And T Cell Leukemogenesis

Objective: To illustrate whether abrrent RNA splicing is involved in T-ALL pathogenesis,this study fucous on the functional roles and regulatory mechanisms of SHQ1,a common elevated gene in distinct T-ALL subtypes,in RNA splicing and T cell leukemogenesis.It's expected to meanwhile provide potential therapeutic targets for treatment.Methods: The specific high expression of SHQ1 in T-ALL was confirmed via bioinformatics analysis.Chromatin immunoprecipitation and Dual-luciferase reporter assay were conducted to reveal the transcriptional activation of SHQ1 by oncogenic NOTCH1.The impact of SHQ1 on T-ALL cell growth and survival was evaluated with short-hairpin RNA(sh RNA)-mediated ablation.Xenograft and fetal liver transplantation model were constructed to investigate whether SHQ1 participates in T cell transformation.RNA sequencing was perfomed to explore the molecular mechanism of SHQ1 regulation of RNA splicing.Minigene assay was carried out to further verify the splicing regulation of SHQ1 on MYC.Meanwhile,by detecting whether artificially expressed MYC could rescue the impaired cell viability caused by SHQ1 loss,the biological significance of SHQ1-MYC axis would be finely determined.Results: Gene expression profiling analysis showed that SHQ1 was elevated in primary T-ALL samples,as compared to normal bone marrow or thymocytes.In T-ALL cell lines as well as primary samples,the expression level of SHQ1 was positively correlated with NOTCH1 activity.Mechanistically,oncogenic NOTCH1 directly binds to the SHQ1 promoter and activates its transcription.SHQ1 depletion attenuated cell growth and induced noticeable apoptosis in vitro,but had minimal effect on normal cells.Consistently,SHQ1 loss prolonged animal survival and decreased leukemic cell burden in vivo.RNA-seq revealed that when SHQ1 was inactivated,the splicing efficiency of multiple oncogenes was retarded,resulting in decreased abundance of mature m RNA.As a key effector downstream of SHQ1 regulation of splicing,MYC mediates the modulation of glycolysis by SHQ1.And overexpression of MYC rescued,at partially,the growth inhibition and apoptosis induced by SHQ1 depletion.Conclusion: We herein define a vital role of SHQ1 in supporting T cell leukemogenesis.Sustained SHQ1 expression,induced by oncogenic NOTCH1,is essential for T-ALL cell growth in vitro and leukemogenesis in vivo.The profound role of SHQ1 in leukemogenesis relies on successful H/ACA sno RNP assembly,enabling efficient global pre-m RNA splicing.These findings provide important insights of how SHQ1-mediated RNA modification and pre-m RNA splicing affect tumorigenesis,deepen our understanding of post-transcriptional regulation of oncogene MYC,and also offer therapeutic opportunity for T-ALL patients by targeting of SHQ1 or spliceosome.