Camboni, T. | Search bioRxiv

bioRxiv2025

Red Blood Cell-derived Extracellular Vesicles enable Cisplatin and Cetuximab Synergistic Therapy against Triple-Negative Breast Cancer

BackgroundTriple-negative breast cancer is an aggressive breast cancer subtype characterized by the absence of human epidermal growth factor receptor 2, estrogen and progesterone receptors, limiting targeted therapy options. Cisplatin, a chemotherapeutic agent, induces DNA damage and exhibits some efficacy against triple-negative breast cancer, but its effectiveness is often reduced by chemoresistance and systemic toxicity. A very promising strategy to augment cisplatin treatment can be based on combining it with the biologic Cetuximab, an epidermal growth factor receptor inhibitor, which boosts cisplatin efficacy by inducing ferroptosis. ResultsTo optimize this strategy in a biocompatible and precise manner, we developed a nanoplatform based on red blood cell-derived extracellular vesicles for the combined delivery of Cetuximab and cisplatin, enabling immune evasion, and the possibility of autologous personalization and GMP-compliant production. Owing to their DNA-free lumen and lack of EGFR, RBC-EVs preserve cisplatin activity and prevent interference with cetuximab. This formulation enhances cisplatins cytotoxicity by up to 50%, as shown in vitro and in patient-derived organoids. It effectively reduces chemoresistance by downregulating hypoxia-related genes and promoting ferroptosis, additionally, it improves cisplatins cytotoxic effects while reducing hemotoxicity compared to the administration of free cisplatin. ConclusionsThese findings highlight the potential of red blood cell-derived extracellular vesicles as a biocompatible delivery system enabling combined therapy and offering a promising strategy to overcome current limitations in TNBC treatment.

cell biology↗

bioRxiv2024

Pathological PNPase variants with altered RNA binding and degradation activity affect the phenotype of bacterial and human cell models

Human PNPase (hPNPase) is an essential RNA exonuclease located in mitochondria, where it contributes to RNA import from the cytoplasm, degradation of mitochondrial RNA, and R-loop homeostasis. Biallelic mutations in the hPNPase PNPT1 gene cause different genetic diseases, ranging from hereditary hearing loss to Leigh syndrome. In this work, we used an Escherichia coli model we recently developed to test the effects of four pathological PNPT1 mutations associated with diseases of different severity. Moreover, we generated a new human cell model by introducing PNPT1 mutations into 293T cells via CRISPR-Cas editing. Notably, the bacterial cells expressing the different mutant alleles exhibited similar phenotypes consistent with hPNPase loss of function. In contrast, the human cell model responded differently to the two mutations tested, with responses correlating with the severity of the respective pathologies. We interpreted the data derived from both models in the light of the in vitro RNA binding and degradation activity of the purified wild-type and mutated hPNPase variants. We found that all pathogenic mutations tested caused defects in protein assembly and affected the degradation and RNA binding efficiency to varying degrees. However, the severity of the conditions caused by different mutations did not correlate with the catalytic activity of the mutant proteins. Also, we demonstrated that human PNPase, like its bacterial orthologue, is capable of trimming ssDNA and some mutations inhibit such activity.

genetics↗