Adrenomedullin Expression Characterizes Leukemia Stem Cells and Associates With an Inflammatory Signature in Acute Myeloid Leukemia

Identification and Validation of a Prognostic Signature Derived from the Cancer Stem Cells for Oral Squamous Cell Carcinoma

The progression and metastasis of oral squamous cell carcinoma (OSCC) are highly influenced by cancer stem cells (CSCs) due to their unique self-renewal and plasticity. In this study, data were obtained from a single-cell RNA-sequencing dataset (GSE172577) in the GEO database, and LASSO-Cox regression analysis was performed on 1344 CSCs-related genes to establish a six-gene prognostic signature (6-GPS) consisting of ADM, POLR1D, PTGR1, RPL35A, PGK1, and P4HA1. High-risk scores were significantly associated with unfavorable survival outcomes, and these features were thoroughly validated in the ICGC. The results of nomograms, calibration plots, and ROC curves confirmed the good prognostic accuracy of 6-GPS for OSCC. Additionally, the knockdown of ADM or POLR1D genes may significantly inhibit the proliferation, migration, and invasion of OSCC cells through the JAK/HIF-1 pathway. Furthermore, cell-cycle arrest occurred in the G1 phase by suppressing Cyclin D1. In summary, 6-GPS may play a crucial role in the occurrence and development of OSCC and has the potential to be developed further as a diagnostic, therapeutic, and prognostic tool for OSCC.

Ferroptosis in acute leukemia

ABSTRACT

Ferroptosis is an iron-dependent cell death pathway that is different from apoptosis, pyroptosis, and necrosis. The main characteristics of ferroptosis are the Fenton reaction mediated by intracellular free divalent iron ions, lipid peroxidation of cell membrane lipids, and inhibition of the anti-lipid peroxidation activity of intracellular glutathione peroxidase 4 (GPX4). Recent studies have shown that ferroptosis can be involved in the pathological processes of many disorders, such as ischemia-reperfusion injury, nervous system diseases, and blood diseases. However, the specific mechanisms by which ferroptosis participates in the occurrence and development of acute leukemia still need to be more fully and deeply studied. This article reviews the characteristics of ferroptosis and the regulatory mechanisms promoting or inhibiting ferroptosis. More importantly, it further discusses the role of ferroptosis in acute leukemia and predicts a change in treatment strategy brought about by increased knowledge of the role of ferroptosis in acute leukemia.

An inflammatory response-related gene signature associated with immune status and prognosis of acute myeloid leukemia

OBJECTIVE

To determine the prognostic significance of inflammatory response-associated genes in acute myeloid leukemia (AML).

METHODS

Transcriptomic profiles and related clinical information of AML patients were acquired from a public database. To establish a multi-gene prognosis signature, we performed least absolute shrinkage and selection operator Cox analysis for the TCGA cohort and evaluated the ICGC cohort for verification. Subsequently, Kaplan-Meier analysis was carried out to compare the overall survival (OS) rates between high- and low-risk groups. Biological function and single-sample gene set enrichment (ssGSEA) analyses were employed to investigate the association of risk score with immune status and the tumor microenvironment. Prognostic gene expression levels in AML samples and normal controls were confirmed by qRT-PCR and immunofluorescence.

RESULTS

We identified a potential inflammatory response-related signature comprising 11 differentially expressed genes, including ACVR2A, CCL22, EBI3, EDN1, FFAR2, HRH1, ICOSLG, IL-10, INHBA, ITGB3, and LAMP3, and found that AML patients with high expression levels in the high-risk group had poor OS rates. Biological function analyses revealed that prognostic genes mainly participated in inflammation and immunity signaling pathways. Analyses of cancer-infiltrating immunocytes indicated that in high-risk patients, the immune suppressive microenvironment was significantly affected. The expression of the inflammation reaction-associated signature was found to be associated with susceptibility to chemotherapy. There was a significant difference in prognostic gene expression between AML and control tissues.

CONCLUSION

A novel inflammatory response-related signature was developed with 11 candidate genes to predict prognosis and immune status in AML patients.

Release of IFN-γ by acute myeloid leukemia cells remodels bone marrow immune microenvironment by inducing regulatory T cells

PURPOSE

The stromal and immune bone marrow (BM) landscape is emerging as a crucial determinant for acute myeloid leukemia (AML). Regulatory T cells (Tregs) are enriched in the AML microenvironment, but the underlying mechanisms are poorly elucidated. Here, we addressed the effect of IFN-γ released by AML cells in BM Tregs induction and its impact on AML prognosis.

EXPERIMENTAL DESIGN

BM aspirates from AML patients were subdivided according to IFNG expression. Gene expression profiles in INFGhigh and IFNGlow samples were compared by microarray and NanoString analysis and used to compute a prognostic index. The IFN-g release effect on the BM microenvironment was investigated in mesenchymal stromal cell (MSC)/AML cell co-cultures. In mice, AML cells silenced for IFN-γ expression were injected intrabone.

RESULTS

IFNGhigh AMLsamples showed an upregulation of inflammatory genes, usually correlated with a good prognosis in cancer. By contrast, in AML patients, high IFNG expression associated with poor overall survival. Notably, IFN-g release by AML cells positively correlated with a higher BM suppressive Tregs' frequency. In co-culture experiments, IFNGhigh AML cells modified MSC transcriptome by up-regulating IFN-γ-dependent genes related to Treg induction, including indoleamine 2,3-dioxygenase 1 (IDO1). IDO1 inhibitor abrogated the effect of IFN-γ release by AML cells on MSC-derived Treg induction. Invivo, the genetic ablation of IFN-γ production by AML cells reduced MSC IDO1 expression and Treg infiltration, hindering AML engraftment.

CONCLUSIONS

IFN-g release by AML cells induces an immune-regulatory program in MSCs and remodels BM immunological landscape toward Treg induction, contributing to an immunotolerant microenvironment.