Gene SH3BGRL3 regulates acute myeloid leukemia progression through circRNA_0010984 based on competitive endogenous RNA mechanism.

Introduction: Acute myeloid leukemia (AML) is a malignant proliferative disease affecting the bone marrow hematopoietic system and has a poor long-term outcome. Exploring genes that affect the malignant proliferation of AML cells can facilitate the accurate diagnosis and treatment of AML. Studies have confirmed that circular RNA (circRNA) is positively correlated with its linear gene expression. Therefore, by exploring the effect of SH3BGRL3 on the malignant proliferation of leukemia, we further studied the role of circRNA produced by its exon cyclization in the occurrence and development of tumors. Methods: Genes with protein-coding function obtained from the TCGA database. we detected the expression of SH3BGRL3 and circRNA_0010984 by real-time quantitative polymerase chain reaction (qRT-PCR). We synthesized plasmid vectors and carried out cell experiments, including cell proliferation, cell cycle and cell differentiation by cell transfection. We also studied the transfection plasmid vector (PLVX-SHRNA2-PURO) combined with a drug (daunorubicin) to observe the therapeutic effect. The miR-375 binding site of circRNA_0010984 was queried using the circinteractome databases, and the relationship was validated by RNA immunoprecipitation and Dual-luciferase reporter assay. Finally, a protein-protein interaction network was constructed with a STRING database. GO and KEGG functional enrichment identified mRNA-related functions and signaling pathways regulated by miR-375. Results: We identified the related gene SH3BGRL3 in AML and explored the circRNA_0010984 produced by its cyclization. It has a certain effect on the disease progression. In addition, we verified the function of circRNA_0010984. We found that circSH3BGRL3 knockdown specifically inhibited the proliferation of AML cell lines and blocked the cell cycle. We then discussed the related molecular biological mechanisms. CircSH3BGRL3 acts as an endogenous sponge for miR-375 to isolate miR-375 and inhibits its activity, increases the expression of its target YAP1, and ultimately activates the Hippo signaling pathway involved in malignant tumor proliferation. Discussion: We found that SH3BGRL3 and circRNA_0010984 are important to AML. circRNA_0010984 was significantly up-regulated in AML and promoted cell proliferation by regulating miR-375 through molecular sponge action.

NDRG3 regulates imatinib resistance by promoting ß­catenin accumulation in the nucleus in chronic myelogenous leukemia.

Imatinib resistance in chronic myelogenous leukemia (CML) is a clinical problem. The present study examined the role of N­Myc downstream regulatory gene 3 (NDRG3) in imatinib resistance in CML. Quantitative PCR demonstrated that NDRG3 was highly expressed in patients with CML. Cell Counting Kit (CCK)­8 experiments proved that NDRG3 promoted the proliferation of K562 CML cells and enhanced imatinib resistance. Dual­luciferase assay showed that microRNA (miR)­204­5p inhibited expression of NDRG3 and immunofluorescence experiments showed that NDRG3 promoted accumulation of ß­catenin in the nucleus, thereby increasing the expression of downstream drug resistance­ and cell cycle­associated factors (c­Myc and MDR1). At the same time, cell proliferation experiments showed that ß­catenin played a role in cell proliferation and drug resistance. Co­transfection with small interfering (si)­ß­catenin partially reversed the effect of NDRG3. This finding indicated that NDRG3 plays an important role in imatinib resistance and miR­204­5p and ß­catenin are involved in the biological behavior of NDRG3. The present results provide theoretical support for overcoming drug resistance in CML.

TRIB2 regulates the expression of miR­33a­5p through the ERK/c­Fos pathway to affect the imatinib resistance of chronic myeloid leukemia cells.

Chronic myeloid leukemia (CML) is a hematological disease, and imatinib (IM) resistance represents a major problem for its clinical treatment. In the present study, the role of tribbles pseudokinase 2 (TRIB2) in IM resistance of CML and the possible mechanism were investigated. It was found that TRIB2 was highly expressed in IM­resistant patients with CML through the Oncomine database and this conclusion was confirmed using reverse transcription­quantitative PCR and western blot experiments. Knockdown of TRIB2 was found to increase the drug sensitivity of KG cells to IM using Cell­Counting Kit­8 (CCK­8) assays, and the low­expression TRIB2 mice were further found to be more sensitive to the IM and have a higher survival rate in leukemia model mice. Moreover, using western blot and luciferase experiments, it was found that TRIB2 could regulate c­Fos through the ERK signaling pathway, and c­Fos suppressed the transcriptional activity and the expression of miR­33a­5p. Further investigation identified that the binding site for c­Fos to function on miR­33a­5p was the ­958­965 region. Finally, CCK­8 assays and western blot experiments demonstrated that miR­33a­5p could inhibit the proliferation of KG cells and reduce IM resistance by suppressing the expression of HMGA2. In conclusion, it was demonstrated that TRIB2 regulates miR­33a­5p to reverse IM resistance in CML, which may help identify novel targets and therapeutic strategies for the clinical treatment of IM resistance.