Lipids and the cancer stemness regulatory system in acute myeloid leukemia

ICAT mediates the inhibition of stemness and tumorigenesis in acute myeloid leukemia cells induced by 1,25-(OH)2D3

Background

The role of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) in cancer prevention and treatment is an emerging topic of interest. However, its effects on the stemness of acute myeloid leukemia (AML) cells are poorly understood.

Methods

The proliferation and differentiation of AML cells (HL60 and NB4) were investigated by the CCK-8 assay, immunocytochemical staining, and flow cytometry. The abilities of HL60 and NB4 cells to form spheres were examined by the cell sphere formation assay. In addition, the levels of stemness-associated markers (SOX2, Nanog, OCT4, and c-Myc) in HL60 and NB4 cells were measured by western blotting and quantitative real-time polymerase chain reaction. Moreover, we obtained β-catenin-interacting protein 1 (ICAT)-knockout and ICAT-overexpressing HL-60 cells using gene editing and lentiviral infection techniques and investigated the role of ICAT in modulating the stemness-inhibiting effects of 1,25-(OH)2D3 using the aforementioned experimental methods. Finally, we validated our findings in vivo using NOD/SCID mice.

Results

1,25-(OH)2D3 inhibited the proliferation and stemness of AML cells (HL60 and NB4) and induced their differentiation into monocytes. Additionally, the knockdown of ICAT in HL60 cells attenuated the inhibitory effects of 1,25-(OH)2D3 on proliferation and stemness and suppressed the expression of stemness markers. Conversely, overexpression of ICAT enhanced the aforementioned inhibitory effects of 1,25-(OH)2D3. Consistently, in NOD/SCID mice, 1,25-(OH)2D3 suppressed tumor formation by HL-60 cells, and the effects of ICAT knockdown or overexpression on 1,25-(OH)2D3 aligned with the in vitro findings.

Conclusion

1,25-(OH)2D3 inhibits AML cell stemness, possibly through modulation of the ICAT-mediated Wnt/β-catenin signaling pathway.

Parallel single-cell metabolic analysis and extracellular vesicle profiling reveal vulnerabilities with prognostic significance in acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive disease with a high relapse rate. In this study, we map the metabolic profile of CD34+(CD38low/-) AML cells and the extracellular vesicle signatures in circulation from AML patients at diagnosis. CD34+ AML cells display high antioxidant glutathione levels and enhanced mitochondrial functionality, both associated with poor clinical outcomes. Although CD34+ AML cells are highly dependent on glucose oxidation and glycolysis for energy, those from intermediate- and adverse-risk patients reveal increased mitochondrial dependence. Extracellular vesicles from AML are mainly enriched in stem cell markers and express antioxidant GPX3, with their profiles showing potential prognostic value. Extracellular vesicles enhance mitochondrial functionality and dependence on CD34+ AML cells via the glutathione/GPX4 axis. Notably, extracellular vesicles from adverse-risk patients enhance leukemia cell engraftment in vivo. Here, we show a potential noninvasive approach based on liquid 'cell-extracellular vesicle' biopsy toward a redefined metabolic stratification in AML.

Proteomic and metabolomic exploration in relapse acute myeloid leukemia bone marrow supernatant combined with genetic characteristics

OBJECT

Aim to investigate the multi-omic characteristics of the bone marrow supernatant of relapsed acute myeloid leukemia (AML) and search for proteins and metabolites associated with relapse.

METHODS

A total of 40 bone marrow supernatant from 7 patients with relapsed AML and 33 patients with non-relapsed AML were collected for proteomics and metabonomics analysis. Unsupervised clustering was used to discover the characteristics of proteins and metabolites. The prognostic significances of proteins were assessed concerning the relapse status(including death) and relapse-free survival.

RESULT

Totally 996 proteins and 4,831 metabolites were identified in bone marrow supernatant, and two of 7 clusters were revealed through unsupervised clustering and were associated with ASXL1, TP53, and RUNX1 mutations, which were listed as high-risk factors in the 2022 edition of the WHO classification of tumors of the hematopoietic and lymphoid tissues. Among the identified proteins and metabolites, 57 proteins and 190 metabolites were found to be closely related to relapse.

CONCLUSION

This study has revealed a significant correlation between protein expression in the bone marrow microenvironment of AML and three high-risk mutations: ASXL1, TP53, and RUNX1. Based on this finding, we further identified 227 differential proteins closely associated with these three mutations, as well as 57 proteins directly related to disease recurrence. Additionally, lipid metabolism plays a crucial role in the occurrence and development of AML within its bone marrow microenvironment.

A special issue of Essays in Biochemistry on cancer stem cells

Cancer stem cells (CSCs) are subpopulation of cells within the tumor bulk, which leads to tumor recurrence and therapeutic resistance. Identification of specific CSC targets for detection and efficient cancer therapy are the major hurdles in this research field. In this decade, basic researchers and clinicians made every effort to overcome these challenges to target CSCs using different approaches. This special issue includes a varied collection of review articles with comprehensive discussion on the complexity of CSC heterogeneity, signaling pathways regulating the behaviors of CSCs, the therapeutic resistance mechanism of CSCs, and therapeutic targets against CSCs. These review articles shed light on current advances in understanding of CSC biology.