AKAP9 Upregulation Predicts Unfavorable Prognosis in Pediatric Acute Myeloid Leukemia and Promotes Stemness Properties via the Wnt/β-Catenin Pathway

Construction and validation of key genes-related prognosis model in children with acute myeloid leukaemia

INTRODUCTION

To identify the differentially expressed genes of acute myeloid leukaemia (AML) and construct and verify a survival prognosis model combined with patient survival information.

METHODS

The TARGET database was searched to identify differentially expressed peripheral blood genes in children with AML and healthy children. A gene set functional analysis and pathway analysis were performed using gene ontology and the KEGG pathway. A prognostic model for children with AML was constructed using univariate Cox, LASSO Cox regression and multivariate Cox regression analyses. Time-dependent receiver operating characteristic (ROC) curves were adopted to assess the predictive capacity of the prognostic models.

RESULTS

In total, 1640 differentially expressed genes were screened (1119 upregulated and 521 downregulated genes). The differentially expressed genes were mainly involved in nutrient metabolism and cytochrome P450 metabolism. Six key genes related to the prognosis of AML, FAM157A, GPR78, IRX5, RP4-800G7.1, RP11-179H18.5 and RP11-61N20.3, were identified. Kaplan-Meier curves indicated that 3-year and 5-year overall survival was significantly higher in the low-risk group than in the high-risk group. The area under the ROC curve was 0.722. At different stages of AML, FAM157A and RP4-800G7.1 exhibited significant differences in expression. The expression levels of FAM157A were significantly decreased in AML, whereas the expression levels of GPR78, IRX5, RP4-800G7.1, RP11-179H18.5 and RP11-61N20.3 were significantly increased in AML.

CONCLUSION

A prognosis-related gene model of AML was successfully constructed, and the expression levels of the model genes varied with AML stage.

Expression of RASSF1A, DIRAS3, and AKAP9 Genes in Thyroid Lesions: Implications for Differential Diagnosis and Prognosis of Thyroid Carcinomas

Thyroid carcinoma is the primary endocrine malignancy worldwide. The preoperative examination of thyroid tissue lesion is often unclear. Approximately 25% of thyroid cancers cannot be diagnosed definitively without post-surgery histopathological examination. The assessment of diagnostic and differential markers of thyroid cancers is needed to improve preoperative diagnosis and reduce unnecessary treatments. Here, we assessed the expression of RASSF1A, DIRAS3, and AKAP9 genes, and the presence of BRAF V600E point mutation in benign and malignant thyroid lesions in a Polish cohort (120 patients). We have also performed a comparative analysis of gene expression using data obtained from the Gene Expression Omnibus (GEO) database (307 samples). The expression of RASSF1A and DIRAS3 was decreased, whereas AKAP9's was increased in pathologically changed thyroid compared with normal thyroid tissue, and significantly correlated with e.g., histopathological type of lesion papillary thyroid cancer (PTC) vs follicular thyroid cancer (FTC), patient's age, tumour stage, or its encapsulation. The receiver operating characteristic (ROC) analysis for the more aggressive FTC subtype differential marker suggests value in estimating RASSF1A and AKAP9 expression, with their area under curve (AUC), specificity, and sensitivity at 0.743 (95% CI: 0.548-0.938), 82.2%, and 66.7%; for RASSF1A, and 0.848 (95% CI: 0.698-0.998), 54.8%, and 100%, for AKAP9. Our research gives new insight into the basis of the aggressiveness and progression of thyroid cancers, and provides information on potential differential markers that may improve preoperative diagnosis.

Golgi organization is a determinant of stem cell function in the small intestine

Cell-to-cell signalling between niche and stem cells regulates tissue regeneration. While the identity of many mediating factors is known, it is largely unknown whether stem cells optimize their receptiveness to niche signals according to the niche organization. Here, we show that Lgr5+ small intestinal stem cells (ISCs) regulate the morphology and orientation of their secretory apparatus to match the niche architecture, and to increase transport efficiency of niche signal receptors. Unlike the progenitor cells lacking lateral niche contacts, ISCs orient Golgi apparatus laterally towards Paneth cells of the epithelial niche, and divide Golgi into multiple stacks reflecting the number of Paneth cell contacts. Stem cells with a higher number of lateral Golgi transported Epidermal growth factor receptor (Egfr) with a higher efficiency than cells with one Golgi. The lateral Golgi orientation and enhanced Egfr transport required A-kinase anchor protein 9 (Akap9), and was necessary for normal regenerative capacity in vitro . Moreover, reduced Akap9 in aged ISCs renders ISCs insensitive to niche-dependent modulation of Golgi stack number and transport efficiency. Our results reveal stem cell-specific Golgi complex configuration that facilitates efficient niche signal reception and tissue regeneration, which is compromised in the aged epithelium.