GSE122354
RNF8 is responsible for ATRA resistance in variant acute promyelocytic leukemia with GTF2I/RARA fusion and the inhibition of the ubiquitin-proteasome pathway contributes to the reversion of ATRA resistance
GTF2I-RARA is a newly identified RARA fusion gene in variant acute promyelocytic leukemia (APL) with t(7;17)(q11;q21). Clinical manifestation in the patient showed that it is a sort of ATRA-insensitive oncogene and is different from the classic PML-RARA in terms of therapeutic reaction. To reveal the functional characteristics and regulating mechanism of the GTF2I-RARA fusion gene, we established a GTF2I-RARA-transfected HL-60 cell model and confirmed its resistance to ATRA. Compared with PML-RARA, GTF2I-RARA has a higher affinity to HDAC3 under the treatment of ATRA. Using the ChIP-sequencing approach, we identified 221 GTF2I-RARA binding sites in model cells, and found that the RING finger protein 8(RNF8) is a target gene of GTF2I-RARA, which participated in the disease progression and therapy resistance in APL with GTF2I-RARA transcript. The elevated RNF8 expression promotes the interaction between RARA and RNF8 and induced RARA ubiquitylation and degradation, resulting in attenuated transcriptional activation of RARA. Our results suggested that RNF8 is a key GTF2I-RARA downstream event. Using the combination of MG132 and ATRA to treat the GTF2I-RARA-HL-60 cells, a synergistic effect leading to GTF2I-RARA-HL-60 cell differentiation was confirmed. Taken together, the targeting of RNF8 may be an alternative choice for treatment in variant APL with GTF2I-RARA fusion. Overall design: exam the target gene of GTF2I-RARA in hl60 cell