Lysosomal acid lipase A modulates leukemia stem cell response to venetoclax/tyrosine kinase inhibitor combination therapy in blast phase chronic myeloid leukemia.

The treatment of blast phase chronic myeloid leukemia (bpCML) remains a challenge due at least in part to drug resistance of leukemia stem cells (LSCs). Recent clinical evidence suggests that the BCL-2 inhibitor venetoclax in combination with ABL-targeting tyrosine kinase inhibitors (TKIs) can eradicate bpCML LSCs. In this report, we employed preclinical models of bpCML to investigate the efficacy and underlying mechanism of LSC-targeting with venetoclax/TKI combinations. Transcriptional analysis of LSCs exposed to venetoclax and dasatinib revealed upregulation of genes involved in lysosomal biology, in particular lysosomal acid lipase A (LIPA), a regulator of free fatty acids. Metabolomic analysis confirmed increased levels of free fatty acids in response to venetoclax/dasatinib. Pre-treatment of leukemia cells with bafilomycin, a specific lysosome inhibitor, or genetic perturbation of LIPA, resulted in increased sensitivity of leukemia cells toward venetoclax/dasatinib, implicating LIPA in treatment resistance. Importantly, venetoclax/dasatinib treatment does not affect normal stem cell function, suggestive of a leukemia-specific response. These results demonstrate that venetoclax/dasatinib is an LSCselective regimen in bpCML and that disrupting LIPA and fatty acid transport enhances venetoclax/dasatinib response in targeting LSCs, providing a rationale for exploring lysosomal disruption as an adjunct therapeutic strategy to prolong disease remission.

TP53 in MDS and AML: Biological and clinical advances.

Recently, the WHO-5 and the ICC 2022 criteria have emphasized poor prognosis in AML/MDS patients with multi-hit TP53 mutations, whereas mutated TP53 plays a critical role in tumorigenesis, drawing substantial interest in exploring its biological behaviors. Diverse characteristics of TP53 mutations, including types, VAF, CNVs, allelic status, karyotypes, and concurrent mutations have been extensively studied. Novel potential targets and comprehensive treatment strategies nowadays are under swift development, owing to great advances in technology. However, accurately predicting prognosis of patients with TP53-mutated myeloid neoplasms remains challenging. And there is still a lack of effective treatment for those patients.

Impact of monocytic differentiation on acute myeloid leukemia patients treated with venetoclax and hypomethylating agents.

INTRODUCTION: Although the combination of venetoclax (VEN) and hypomethylating agents (HMAs) results in impressive efficacy in acute myeloid leukemia (AML), there is still a subset of patients who are refractory. We investigated the outcomes of AML patients with monocytic differentiation who were treated with frontline VEN/HMA. METHODS: A total of 155 patients with newly diagnosed AML treated with frontline VEN/HMA were enrolled in the study. Monocyte-like AML was identified by flow cytometry with typical expression of monocytic markers, and M5 was identified according to French, American, and British category. We compared the outcomes of patients with different characteristics. RESULTS: The rate of complete remission (CR) and CR with incomplete recovery of blood counts (CRi), progression-free survival (PFS), and overall survival (OS) in monocyte-like AML were inferior to those in nonmonocyte-like AML (CR/CRi rates, 26.7% vs. 80.0%, p < 0.001; median PFS, 2.1 vs. 8.8 months, p < 0.001; median OS, 9.2 vs. 19 months, p = 0.013). CR/CRi rate in M5 was lower than that in non-M5 (60.7% vs. 75.5%, p = 0.049). Multivariate analyses showed that monocyte-like AML was associated with lower odds of CR/CRi and higher risk of progression. CONCLUSION: Our study suggested that newly diagnosed AML with a monocytic immunophenotype had a poor prognosis with VEN/HMA treatment.

Targeting Acute Myeloid Leukemia Stem Cells Through Perturbation of Mitochondrial Calcium.

Acute myeloid leukemia stem cells (LSCs) are uniquely reliant on oxidative phosphorylation (OXPHOS) for survival. Moreover, maintenance of OXPHOS is dependent on BCL-2, creating a therapeutic opportunity to target LSCs using the BCL-2 inhibitor venetoclax. While venetoclax-based regimens have shown promising clinical activity, the emergence of drug resistance is prevalent. Thus, in the present study, we investigated how mitochondrial properties may influence venetoclax responsiveness. Our data show that utilization of mitochondrial calcium is fundamentally different between drug-responsive and non-responsive LSCs. By comparison, venetoclax-resistant LSCs demonstrate a more active metabolic (i.e. OXPHOS) status with relatively high levels of calcium. Consequently, we tested genetic and pharmacological approaches to target the mitochondrial calcium uniporter, MCU. We demonstrate that inhibition of calcium uptake reduces OXPHOS and leads to eradication of venetoclax-resistant LSCs. These findings demonstrate a central role for calcium signaling in LSCs and provide an avenue for clinical management of venetoclax resistance.

An updated review of epidemiological characteristics, immune escape, and therapeutic advances of SARS-CoV-2 Omicron XBB.1.5 and other mutants.

The rapid evolution of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has led to the emergence of new variants with different genetic profiles, with important implications for public health. The continued emergence of new variants with unique genetic features and potential changes in biological properties poses significant challenges to public health strategies, vaccine development, and therapeutic interventions. Omicron variants have attracted particular attention due to their rapid spread and numerous mutations in key viral proteins. This review aims to provide an updated and comprehensive assessment of the epidemiological characteristics, immune escape potential, and therapeutic advances of the SARS-CoV-2 Omicron XBB.1.5 variant, as well as other variants.