Pathways, Processes, and Candidate Drugs Associated with a Hoxa Cluster-Dependency Model of Leukemia

Hydrogel-Based Pre-Clinical Evaluation of Repurposed FDA-Approved Drugs for AML

In vivo models of acute myeloid leukemia (AML) are low throughput, and standard liquid culture models fail to recapitulate the mechanical and biochemical properties of the extracellular matrix-rich protective bone marrow niche that contributes to drug resistance. Candidate drug discovery in AML requires advanced synthetic platforms to improve our understanding of the impact of mechanical cues on drug sensitivity in AML. By use of a synthetic, self-assembling peptide hydrogel (SAPH) of modifiable stiffness and composition, a 3D model of the bone marrow niche to screen repurposed FDA-approved drugs has been developed and utilized. AML cell proliferation was dependent on SAPH stiffness, which was optimized to facilitate colony growth. Three candidate FDA-approved drugs were initially screened against the THP-1 cell line and mAF9 primary cells in liquid culture, and EC50 values were used to inform drug sensitivity assays in the peptide hydrogel models. Salinomycin demonstrated efficacy in both an 'early-stage' model in which treatment was added shortly after initiation of AML cell encapsulation, and an 'established' model in which time-encapsulated cells had started to form colonies. Sensitivity to Vidofludimus treatment was not observed in the hydrogel models, and Atorvastatin demonstrated increased sensitivity in the 'established' compared to the 'early-stage' model. AML patient samples were equally sensitive to Salinomycin in the 3D hydrogels and partially sensitive to Atorvastatin. Together, this confirms that AML cell sensitivity is drug- and context-specific and that advanced synthetic platforms for higher throughput are valuable tools for pre-clinical evaluation of candidate anti-AML drugs.

Role of the HOXA cluster in HSC emergence and blood cancer

Hematopoiesis, the process of blood formation, is controlled by a complex developmental program that involves intrinsic and extrinsic regulators. Blood formation is critical to normal embryonic development and during embryogenesis distinct waves of hematopoiesis have been defined that represent the emergence of hematopoietic stem or progenitor cells. The Class I family of homeobox (HOX) genes are also critical for normal embryonic development, whereby mutations are associated with malformations and deformity. Recently, members of the HOXA cluster (comprising 11 genes and non-coding RNA elements) have been associated with the emergence and maintenance of long-term repopulating HSCs. Previous studies identified a gradient of HOXA expression from high in HSCs to low in circulating peripheral cells, indicating their importance in maintaining blood cell numbers and differentiation state. Indeed, dysregulation of HOXA genes either directly or by genetic lesions of upstream regulators correlates with a malignant phenotype. This review discusses the role of the HOXA cluster in both HSC emergence and blood cancer formation highlighting the need for further research to identify specific roles of these master regulators in normal and malignant hematopoiesis.

High expression of HOXA5 is associated with poor prognosis in acute myeloid leukemia

BACKGROUND

HOXA5 is considered as an oncogene in many tumors. This study in- vestigated the HOXA5 expression in Chinese acute myeloid leukemia (AML) patients and evaluated the predictive significance of HOXA5 with a single-center retrospective study.

METHODS

We investigated the expression pattern and prognostic value of HOXA5 in patients with AML through by using a series of databases and various datasets, including the ONCOMINE, TCGA, and STRING datasets. The bone marrow samples of 53 newly diagnosed AML patients (non-M3 subtype) and 19 benign individuals were collected in our center. HOXA5 mRNA expression levels were detected by real-time qPCR, HOXA5 protein expression levels were detected by Western Blot. Clinical data was obtained from inpatient medical records.

RESULTS

Two microarrays in Oncomine showed that the expression level of HOXA5 was significantly upregulated in AML. Our data revealed that AML patients had higher HOXA5 mRNA and protein expression levels than the controls (P < 0.001). The blast percentage in bone marrow of HOXA5 high-expression group was higher that of HOXA5 low-expression group (P < 0.05). Higher expression level of HOXA5 revealed a worse OS in AML (P < 0.05).

CONCLUSION

Our findings suggested that HOXA5 might have the potential ability to act as a diagnostic biomarker and potential therapeutic target for AML.

Identification of Early Recurrence Factors in Childhood and Adolescent B-Cell Acute Lymphoblastic Leukemia Based on Integrated Bioinformatics Analysis

Over the past 50 years, great progress has been made in the diagnosis and treatment of acute lymphoblastic leukemia (ALL), especially in pediatric patients. However, early recurrence is still an important threat to the survival of patients. In this study, we used integrated bioinformatics analysis to look for biomarkers of early recurrence of B-cell ALL (B-ALL) in childhood and adolescent patients. Firstly, we obtained gene expression profiles from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database and the Gene Expression Omnibus (GEO) database. Then, we identified differentially expressed genes (DEGs) based on whether the disease relapsed early. LASSO and Cox regression analysis were applied to identify a subset of four genes: HOXA7, S100A11, S100A10, and IFI44L. A genetic risk score model was constructed based on these four optimal prognostic genes. Time-dependent receiver operating characteristic (ROC) curves were used to evaluate the predictive value of this prognostic model (3-, 5-, and 10-year AUC values >0.7). The risk model was significantly associated with overall survival (OS) and event-free survival in B-ALL (all p < 0.0001). In addition, a high risk score was an independent poor prognostic risk factor for OS (p < 0.001; HR = 3.396; 95% CI: 2.387-4.832). Finally, the genetic risk model was successfully tested in B-ALL using an external validation set. The results suggested that this model could be a novel predictive tool for early recurrence and prognosis of B-ALL.