Auranofin Inhibits T-ALL Progression By Targeting TET1

Background: T-cell acute lymphoblastic leukemia(T-ALL)is a type of T-cell malignant hematologic neoplasm with distorted epigenetic patterns.T-ALL is characterized by rapid progression,a high relapse rate,and a poor prognosis.At present,the clinical treatment of T-ALL mainly included chemotherapy and stem cell transplantation.However,traditional chemotherapy may lead to recurrence and poor prognosis.Thus,it is imperative to find new targeted therapeutic drugs.Demethylase TET1 was found highly expressed in T-ALL patients and required for the proliferation of T-ALL cells.The dysregulation of TET protein has been proved leading to the development of ALL or AML.Thus,TET1 is a potential therapeutic target for T-ALL.Auranofin,a gold-containing compound,has been approved by the FDA in 1985 for the treatment of rheumatoid arthritis.Since then,it has been shown to have strong antitumor activity in chronic lymphocytic leukemia,ovarian cancer,small cell lung cancer,and breast cancer.Our study is in order to explore the anti-tumor activity of auranofin in T-ALL and its mechanism related to epigenetic related molecule TET1,which would provide a new targeted drug for T-ALL.Methods: We constructed a high-throughput screening of FDA-approved drug library by CCK-8 assay,getting drugs that have strong cytotoxicity to T-ALL cell lines.We chose auranofin as a study subject to investigate its role in inhibiting the development of T-ALL.Thus,we performed an RNA-seq to screen for potential targets of auranofin in T-ALL cells.What’s more,we used 5hmC-seq,WGBS sequencing,and Dot-blot assay to detect the changes of global 5hmC and 5m C levels in T-ALL cells after auranofin treatment.Then,we applied SPR assay and HPLC technology to detect the affinity of auranofin with TET1.The downstream genes and pathways were detected by bioinformatic analyses and validated by Western blot and RT-qPCR assay.Results: In this study,we found that Auranofin could downregulate the genomic level of 5hmC in T-ALL cells and suppress the progression of T-ALL by targeting inhibiting the catalytic activity of TET1.Our study also demonstrated that deletion of TET1 could downregulate the expression of c-Myc by decreasing the 5hmC level of cMyc gene and increasing its methylation level.The decreased expression of c-Myc could also downregulate TET1 protein by affecting its stability.TET1 and c-Myc form a negative regulatory loop,leading to the death of T-ALL cell.Conclusion: In this study,we discovered a new application of Auranofin as a TET1 inhibitor.We functionally revealed a negative regulatory loop of the DNA epigenetic related gene TET1 and oncogene c-Myc.We also elucidated the mechanism that Auranofin suppressed T-ALL through the TET1/5hmC/c-Myc signaling pathway,which would provide new ideas for clinical treatment of T-ALL and identification of new targeted drug.