Botton, T. | Search bioRxiv

bioRxiv2025

MELK controls tumor metabolism to promote resistance to melanoma therapy

Melanoma is the most aggressive form of skin cancer, and despite major advances in targeted and immune therapies, durable responses remain limited due to the emergence of resistance mechanisms. Metabolic reprogramming has emerged as a key driver of therapy resistance, allowing tumor cells to adapt to environmental and therapeutic pressures. Here, we identify the maternal embryonic leucine zipper kinase (MELK) as a critical mediator of resistance in melanoma. We demonstrate that MELK stimulates intracellular accumulation of amino acids, leading to activation of mTORC1 signaling and enhanced mitochondrial metabolism and biogenesis. This metabolic shift promotes resistance to immune checkpoint blockade. Importantly, preclinical MELK inhibition sensitizes resistant melanoma cells to immunotherapy, revealing a potential combinatorial strategy to overcome resistance. Our findings establish MELK as a central regulator of metabolic adaptation and therapeutic resistance in melanoma, highlighting its potential as a promising therapeutic target.

cancer biology↗

bioRxiv2024

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↗