LncRNA KCNQ1OT1 contributes to the progression and chemoresistance in acute myeloid leukemia by modulating Tspan3 through suppressing miR-193a-3p.

Acute myeloid leukemia (AML) is an aggressive cancer that invariably produces drug resistance after treatment. The aim is to explore the role of lncRNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (KCNQ1OT1) and associated novel mechanisms in the progression and chemoresistance of AML. The expression of KCNQ1OT1, miR-193a-3p, and Tspan3 was measured by qRT-PCR. The values of IC50 for adriamycin (ADR) and the ability of proliferation were analyzed by CCK-8 assay. Cell migration and invasion were assessed by transwell assay. Cell apoptosis was monitored by flow cytometry assay. The expression of Tspan3, MRP1, P-gp and LRP at the protein level was quantified by western blot. The relationship between miR-193a-3p and KCNQ1OT1 or Tspan3 was predicted by bioinformatics tool Diana and verified by dual-luciferase reporter assay, RIP assay or RNA pull-down assay. KCNQ1OT1 and Tspan3 were up-regulated, while miR-193a-3p was down-regulated in ADR resistant AML samples and cells. KCNQ1OT1 knockdown reduced ADR resistance, inhibited proliferation, migration and invasion but promoted apoptosis of ADR resistant AML cells, miR-193a-3p inhibition reversed these effects. MiR-193a-3p was a target of KCNQ1OT1 and combined with Tspan3 3' untranslated region (3' UTR). Enrichment of miR-193a-3p decreased ADR resistance, inhibited proliferation, migration and invasion and stimulated apoptosis in ADR resistant AML cells, but Tspan3 overexpression overturned these impacts. KCNQ1OT1 aggravates AML progression and chemoresistance to ADR by inducing Tspan3 expression via adsorbing miR-193a-3p in ADR resistant AML cells, providing a theoretical basis for the treatment of AML with chemoresistance.

Sun H ，Sun Y ，Chen Q ，Xu Z ... -  《-》

Long noncoding RNA GAS6 antisense RNA1 silencing attenuates the tumorigenesis of acute myeloid leukemia cells through targeting microRNA-370-3p/Tetraspanin3 axis.

Lei W ，Lin J ，Liu F ，Chen N ... -  《-》

Knockdown of LncRNA-UCA1 suppresses chemoresistance of pediatric AML by inhibiting glycolysis through the microRNA-125a/hexokinase 2 pathway.

Dysregulation of lncRNAs is implicated in chemoresistance in varieties of tumor including acute myeloid leukemia (AML). LncRNA urothelial carcinoma-associated 1 (UCA1) was reported to play an oncogenic role in AML. However, whether UCA1 was involved in chemoresistance in pediatric AML remains unclear. UCA1 expression in AML patients after adriamycin (ADR)-based chemotherapy and ADR-resistant AML cells was examined by qRT-PCR. The effects of UCA1 on the cytotoxicity of ADR and glycolysis were evaluated by MTT assay and measuring the glucose consumption and lactate production in HL60 and HL60/ADR cells, repectively. The protein levels of hypoxia-inducible factor 1α (HIF-1α) and hexokinase 2 (HK2) were determined by Western blot. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to confirm the relationships between UCA1, HK2, and miR-125a. We found that UCA1 expression was upregulated following ADR-based chemotherapy. Knockdown of UCA1 increased the cytotoxic effect of ADR and inhibited HIF-1α-dependent glycolysis in ADR-resistant AML cells. Additionally, UCA1 functioned as a ceRNA of miR-125a by directly binding to miR-125a. HK2, a target of miR-125a, was positively regulated by UCA1 in HL60 and HL60/ADR cells. More notably, UCA1 overexpression overturned miR-125-mediated inhibition on HIF-1α-dependent glycolysis in HL60 and HL60/ADR cells. Furthermore, 2-deoxy-glucose (2-DG) exposure inhibited HIF-1α-dependent glycolysis, and attenuated UCA1-induced increase of chemoresistance in HL60 and HL60/ADR cells. We conclude that knockdown of UCA1 plays a positive role in overcoming the chemoresistance of pediatric AML, through suppressing glycolysis by the miR-125a/HK2 pathway, contributing to a better understanding of the molecular mechanism of chemoresistance in AML.

Zhang Y ，Liu Y ，Xu X 《-》

Tumor suppressor miR-139-5p targets Tspan3 and regulates the progression of acute myeloid leukemia through the PI3K/Akt pathway.

Dysregulation of microRNAs is closely implicated in the initiation and progression of human cancers including acute myeloid leukemia (AML). Though miR-139-5p was reported to be a potent tumor suppressor in adult AML, its underlying molecular mechanism in AML remains to be further defined. Herein, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis were conducted to determine the expressions of miR-139-5p and tetraspanin3 (Tspan3) in AML patients and cells. Luciferase reporter assay, qRT-PCR, and Western blot analysis were carried out to detect the interaction between miR-139-5p and Tspan3. Cell proliferation, cell cycle distribution, invasion, and migration were evaluated by cell counting kit-8, flow cytometry, transwell invasion, and migration assays, respectively. Western blot analysis was conducted to determine phosphorylated-protein kinase B (Akt) and Akt levels. We found that a significant reduction in miR-139-5p expression and a prominent increase in Tspan3 expression were observed in AML patients and cells. Tspan3 was confirmed as a direct target of miR-139-5p and was negatively modulated by miR-139-5p. Rescue experiments showed that overexpression of miR-139-5p constrained cell proliferation, invasion and migration capabilities, and induced cell cycle arrest at the S phase in AML cells, which were partially reversed by Tspan3 overexpression. In addition, we found that miR-139-5p suppressed the phosphoinositide 3-kinase (PI3K)/Akt pathway in AML cells by targeting Tspan3. In conclusion, our study concluded that miR-139-5p suppressed the leukemogenesis in AML cells by targeting Tspan3 through inactivation of the PI3K/Akt pathway, providing a better understanding of AML progression.

Zhang R ，Tang P ，Wang F ，Xing Y ，Jiang Z ，Chen S ，Meng X ，Liu L ，Cao W ，Zhao H ，Ma P ，Chen Y ，An C ，Sun L ... -  《-》

Knockdown of Long Noncoding RNA HOXA-AS2 Suppresses Chemoresistance of Acute Myeloid Leukemia via the miR-520c-3p/S100A4 Axis.

Among different molecular candidates, there is growing data to support that long noncoding RNAs (lncRNAs) play a significant role in acute myeloid leukemia (AML). HOXA-AS2 is significantly overexpressed in a variety of tumors and associated with anti-cancer drug resistance, however, little is known regarding the expression and function of HOXA-AS2 in the chemoresistance of AML. In this study, we aimed to determine the role and molecular mechanism of HOXA-AS2 in adriamycin-based chemotherapy resistance in AML cells. Quantitative real-time PCR was used to detect HOXA-AS2 expression in the BM samples and ADR cell lines, U/A and T/A cells. Furthermore, the effects of HOXA-AS2 silencing on cell proliferation and apoptosis were assessed in vitro by CCK8 and flow cytometry, and on tumor growth in vivo. Furthermore, bioinformatics online programs predicted and luciferase reporter assay were used to validate the association of HOXA-AS2 and miR-520c-3p in AML. In this study, we showed that HOXA-AS2 is significantly upregulated in BM samples from AML patients after treatment with adriamycin-based chemotherapy and in U/A and T/A cells. Knockdown of HOXA-AS2 inhibited ADR cell proliferation in vitro and in vivo and promoted apoptosis. Bioinformatics online programs predicted that HOXA-AS2 sponge miR-520c-3p at 3'-UTR with complementary binding sites, which was validated using luciferase reporter assay and anti-Ago2 RIP assay. HOXA-AS2 could negatively regulate the expression of miR-520c-3p in ADR cells. S100A4 was predicted as a downstream target of miR-520c-3p, which was confirmed by luciferase reporter assay. Our results suggest that HOXA-AS2 plays an important role in the resistance of AML cells to adriamycin. Thus, HOXA-AS2 may represent a therapeutic target for overcoming resistance to adriamycin-based chemotherapy in AML.

Dong X ，Fang Z ，Yu M ，Zhang L ，Xiao R ，Li X ，Pan G ，Liu J ... -  《-》