| Objective:Acute myeloid leukemia(AML)cells depend on glutamine for survival,and existing basic research indicates that glutamine deprivation can exert the anti-leukemia effect.Glutamine transporters mainly include solute carrier family 1,family 6,family 7 and family 38.However,it is unclear which of these transporters plays a more important role in AML.In this study,bioinformatic analysis was combined with experimental study to evaluate the prognostic value of solute carrier family 38 member 1(SLC38A1)in normal karyotype acute myeloid leukemia(CN-AML),to explore the effect of SLC38A1expression on AML cells and its underlying mechanisms.Methods:The expression characteristics of SLC38A1 in AML patients and normal controls were compared using the SLC38A1 gene expression data in two microarray datasets(GSE30029 and GSE63270).The Kaplan-Meier survival curve and Log-Rank rank test were used to study the effect of SLC38A1 on the prognosis of 179 patients with AML and 79 patients with CN-AML in the TCGA database.Multivariate regression analysis of prognostic factors in patients with AML was performed using the Cox regression model.Subsequently,the effects of SLC38A1 expression on the prognosis of CN-AML were verified in the other four GEO microarray datasets.The expression of SLC38A1 was detected by qPCR and Western Blot technique.RNA interference was used to reduce the expression of SLC38A1,and the transport function of SLC38A1 was inhibited by small molecule inhibitorα-methylamino isobutyric acid(MeAIB),then the effect on cell growth was determined by CCK8 assay.To explore the underlying mechanisms,we conducted differential gene analysis,signal pathway enrichment,differential microRNA analysis and TF-miRNA-gene regulatory network construction.Results:SLC38A1 was highly expressed in AML patient samples compared to normal contral.In 179 AML samples,there was little difference in overall survival(OS)and event-free survival(EFS)between patients in the SLC38A1~highigh group and the SLC38A1~lowow group.While in 79 CN-AML samples,SLC38A1~highigh group showed significantly shorter OS(P=0.0222)and EFS(P=0.0101)than SLC38A1~lowow group,the prognostic value of SLC38A1expression was further confirmed in other four independent cohorts.Multivariate regression analysis showed that SLC38A1 was a poor prognostic factor independent of age,gender,WBC,and FLT3-ITD gene status in CN-AML(P=0.024).We showed in our current study that glutamine removal inhibited AML cells,and supplementation withα-KG had a rescue effect.After the application of small molecule inhibitor MeAIB,the growth of AML cells was inhibited in a time-dependent and concentration-dependent manner.RNA interference technology reduced the endogenous expression of SLC38A1,thereby inhibited the growth of AML cells.Differential gene analysis indicated that some important oncogenes such as CDK6,KIT,and MSI2 were up-regulated in the SLC38A1 high expression group,while immune-related genes and transcriptional regulators such as CD86,KLF4,and CEBPB were down-regulated.Signal pathway enrichment revealed up-regulation of transcriptional activation-associated pathways and histone epigenetic modification regulatory pathways.MicroRNA expression profiling revealed that some oncogenic microRNAs including miR-126,miR146b and miR-194 were up-regulated in SLC38A1~highigh patients.Conclusions:SLC38A1 is highly expressed in AML and is an independent prognostic factor in patients with CN-AML.Inhibition of SLC38A1 significantly reduces the growth of AML cells.Meanwhile,the high expression of SLC38A1 is accompanied by the up-regulation of some malignant regulatory factors in AML.These studies indicate that SLC38A1 is an important cancer-promoting factor and potential therapeutic target of AML,and suggest that SLC38A1 may be a novel prognostic stratification marker in CN-AML. |
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