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Zerhouni, M.

Publications and source records attributed to Zerhouni, M..

3 recordsLinked to original sources

Dual targeting of GPX4 and TXNRD1 triggers eradication of AML cells through induction of apoptosis and ferroptosis

MyeloDysplastic Syndromes (MDS) are a group of heterogeneous hematological disorders characterized by bone marrow failure and abnormal hematopoietic cell expansion, often progressing to acute myeloid leukemia (AML). Current treatments for AML and high-risk MDS have limited efficacy, requiring the exploration of new therapeutic approaches. Recent research highlighted the potential of inducing cell death through ferroptosis, either independently or alongside traditional chemotherapy, as promising approaches for treating MDS/AML cells. We described here two novel compounds, HA344 and #231, capable of targeting both ferroptosis and apoptosis, leading to the effective eradication of cell lines and primary blasts from MDS/AML patients, while sparing normal hematopoietic cells. RNASeq analysis identified oxidation reduction and apoptotic processes as highly significant induced pathways in two different AML cell lines. Using click-chemistry approaches coupled to mass spectrometry, we identified glutathione peroxidase 4 (GPX4) and thioredoxin reductase 1 (TXNRD1) as the main targets of HA344 and #231 in a large panel of AML cells. Accordingly, both compounds inhibited GPX4 and TXNRD1 activity in the micromolar range and triggered GPX4 degradation. Moreover, using recombinant GPX4 carrying or not a selenium (GPX4-Se and GPX4-S), we confirmed by mass spectrometry that HA344 and #231 bind more efficiently GPX4-Se than GPX4-S. In conclusion, these compounds might represent a new pharmacological approach in the treatment of MDS and AML, offering a potential avenue for future therapies.

biochemistry↗

Selenocysteine tRNA methylation promotes oxidative stress resistance in melanoma metastasis

Selenocysteine-containing proteins play a central role in redox homeostasis. Their translation is a highly regulated process, dependent upon two tRNASec isodecoders differing by a single 2-O-ribose methylation, called Um34. We characterized FTSJ1 as the Um34 methyltransferase and show that its activity is required for efficient selenocysteine insertion at the UGA stop codon during translation. Specifically, Loss of Um34 leads to ribosomal stalling and decreased UGA recoding. FTSJ1-deficient cells are more sensitive to oxidative stress and have decreased metastatic colonization in xenograft models of melanoma metastasis. We found that FTSJ1 mediates efficient translation of selenoproteins essential for the cellular antioxidant response. Our findings uncover a role for tRNASec Um34 modification in oxidative stress resistance and highlight FTSJ1 as a potential therapeutic target specific for metastatic disease.

cancer biology↗

NADK Isoform 3 promotes oxidative stress resistance and melanoma metastasis

Metastasizing cancer cells encounter a multitude of stresses throughout the metastatic cascade. Oxidative stress is known to be a major barrier for metastatic colonization, such that metastasizing cancer cells must rewire their metabolic pathways to increase their antioxidant capacity. NADPH is essential for regeneration of cellular antioxidants and several NADPH-regenerating pathways have been shown to play a role in metastasis. We have found that metastatic melanoma cells have increased levels of both NADPH and NADP+ suggesting increased de novo biosynthesis of NADP+. De novo biosynthesis of NADP+ occurs through a single enzymatic reaction catalyzed by NAD+ kinase (NADK). Here we show that different NADK isoforms are differentially expressed in metastatic melanoma cells, with Isoform 3 being specifically upregulated in metastasis. We find that Isoform 3 is more potent in expanding the NADP(H) pools, increasing oxidative stress resistance and promoting metastatic colonization compared to Isoform 1. We have found that Isoform 3 is transcriptionally upregulated by oxidative stress through the action of NRF2. Together, our work presents a previously uncharacterized role of NADK isoforms in oxidative stress resistance and metastasis and suggests that NADK Isoform 3 is a potential therapeutic target in metastatic disease.

cancer biology↗