CLL remains an incurable disease in spite of the many new compounds being tested. Arsenic trioxide (ATO) induces apoptosis in all CLL cell types and could constitute an efficient therapy. To further explore this, we have studied the gene expression profile induced by ATO in CLL cells. ATO modulated many genes, largely involved in oxidative stress, being HMOX1 the most upregulated gene, also induced at the protein level. ATO also increased MMP-9, as we previously observed, both at the mRNA and protein level. Using specific inhibitors, qPCR analyses, and gene silencing approaches we demonstrate that upregulation of MMP-9 by ATO involved activation of the p38 MAPK/AP-1 signaling pathway. Moreover, gene silencing HMOX1 or inhibiting HMOX1 activity enhanced p38 MAPK phosphorylation and c-jun expression/activation, resulting in transcriptional upregulation of MMP-9. Overexpression of HMOX1 or enhancement of its activity, had the opposite effect. Cell viability analyses upon modulation of HMOX1 expression or activity demonstrated that HMOX1 had a pro-apoptotic role and enhanced the cytotoxic effect of ATO in CLL cells. We have therefore identified a new mechanism in which HMOX1 plays a central role in the response of CLL cells to ATO and in the regulation of the anti-apoptotic protein MMP-9. Thus, HMOX1 arises as a new therapeutic target in CLL and the combination of HMOX1 modulators with ATO may constitute an efficient therapeutic strategy in CLL.
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http://dx.doi.org/10.18632/oncotarget.13091 | DOI Listing |
Nat Commun
January 2025
Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Chronic lymphocytic leukemia is a malignant lymphoproliferative disorder for which primary or acquired drug resistance represents a major challenge. To investigate the underlying molecular mechanisms, we generate a mouse model of ibrutinib resistance, in which, after initial treatment response, relapse under therapy occurrs with an aggressive outgrowth of malignant cells, resembling observations in patients. A comparative analysis of exome, transcriptome and proteome of sorted leukemic murine cells during treatment and after relapse suggests alterations in the proteasome activity as a driver of ibrutinib resistance.
View Article and Find Full Text PDFBiomolecules
January 2025
National Center for Global Health, Italian Institute of Health, 00161 Rome, Italy.
In chronic lymphocytic leukemia (CLL), natural killer (NK) cells show a dysfunctional phenotype that correlates with disease progression. Our aim was to restore NK cell functionality in CLL through a specifically targeted IL15-stimulating activity; IL15 targeting could, in fact, potentiate the activity of NK cells and reduce off-target effects. We designed and developed a cis-acting immunocytokine composed of an anti-CD56 single-chain Fragment variable (scFv) and IL15, labeled scFvB1IL15.
View Article and Find Full Text PDFCancers (Basel)
January 2025
Biosciences Institute & Newcastle University Cancer Centre, Medical Faculty, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Chronic lymphocytic leukemia (CLL) treatment has transitioned from traditional chemotherapy to more targeted therapies, but challenges such as resistance and suboptimal responses persist. This study aimed to evaluate HDM201, a second-generation MDM2-p53 binding antagonist, as a novel therapeutic strategy for CLL, with a focus on its effectiveness across different genetic contexts. We utilized a panel of B cell leukemia-derived cell lines with varying statuses, including -knockout (KO) derivatives of the human B cell line Nalm-6, and assessed the impact of HDM201 on primary CLL samples with both wild-type and mutant backgrounds.
View Article and Find Full Text PDFCancers (Basel)
January 2025
Division of Hematology and Medical Oncology, University of Washington, Seattle, WA 98195, USA.
Pathway inhibitors targeting Bruton tyrosine kinase (BTK) and B-cell lymphoma-2 (BCL-2) have dramatically changed the treatment landscape for both treatment-naïve and relapsed/refractory chronic lymphocytic leukemia (CLL). However, with increased utilization, a growing number of patients will experience progressive disease on both agents. This subgroup of "double refractory" patients has limited treatment options and poor prognosis.
View Article and Find Full Text PDFCancers (Basel)
January 2025
Department of Clinical Immunology, Medical University of Lublin, 20-093 Lublin, Poland.
Background/objectives: The current study explores the impact of CLL on γδ T cells and, in an attempt to better understand the sources of immunosuppression, assesses the impact of M-MDSCs on γδ T cells in vitro.
Methods: The study included 163 CLL patients and 34 healthy volunteers. γδ T cells were screened with flow cytometry, including NKG2D, Fas, FasL, and TRAIL staining.
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