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Biology subjects

Marques, M. A.

Publications and source records attributed to Marques, M. A..

2 recordsLinked to original sources

Oncogenic Phase Transitions: How Mutant p53 Drives Amyloid Formation in p63 and p73 Liquid Droplets

Phase separation (PS) of p53 is critical in its path to amyloid aggregation, a process linked to cancer. P63 and p73 exhibit dual roles as tumor suppressors and oncogenes and are often heightened in tumors. Their coaggregation has been proposed in cancer, yet their PS contribution remains unknown. This study investigates the phase behaviors of p53, p63, and p73. P63 and p73 undergo liquid-liquid phase separation (LLPS). Unlike p53, p63 and p73 do not form amyloids under increased temperatures, underscoring an aspect of the processes involved in cancer. Unlike p63 and p73, wild-type and the M237I mutant p53 initially form droplets at 4{degrees}C, but at temperatures up to 37{degrees}C, they begin to aggregate and bind to Congo red, showing amyloidogenesis. Intriguingly, mutant p53 promotes amyloid-like states in p63 and p73 and hijacks p73 into membrane less organelles. Wild-type p53 has a moderate effect on p63 and p73s amyloid aggregation. Additionally, heparin prevents the prion-like aggregation of p63 and p73 induced by p53. Our results shed light on how mutant and wild-type p53 may trigger amyloid aggregation of p63 and p73, revealing the capacity of p53 amyloid droplets within cancer. These insights expand the possibilities for developing cancer therapies targeting the prion-like conversion of p63 and p73 influenced by mutated p53. RelevanceThe prion-like action of mutant p53 on p63 and p73 droplets would be the basis for an oncogenic gain of function of the p53 mutation.

cancer biology↗

Modelling glioblastoma tumour-host cell interactions using adult brain organotypic slice co-culture

Glioblastoma (GBM) is an aggressive incurable brain cancer. The cells that fuel the growth of tumours resemble neural stem cells found in the developing and adult mammalian forebrain. These are referred to as GBM stem cells (GSCs). Similar to neural stem cells, GSCs exhibit a variety of phenotypic states: dormant, quiescent, proliferative and differentiating. How environmental cues within the brain influence these distinct states is not well understood. Laboratory models of GBM tumours can be generated using either genetically engineered mouse models, or via intracranial transplantation of cultured tumour initiating cells (mouse or human). Unfortunately, these approaches are expensive, time-consuming, low-throughput and ill-suited for monitoring of live cell behaviours. Here we explored whole adult brain coronal organotypic slices as a complementary strategy to remove the experimental bottleneck. Mouse adult brain slices remain viable in a neural stem cell serum-free basal media for several weeks. GSCs can therefore be easily microinjected into specific anatomical sites ex vivo. We demonstrated distinct responses of engrafted GSCs to different microenvironments in the brain. Within the subependymal zone - one of the adult neural stem cell niches - a subset of injected tumour cells could effectively engraft and respond to endothelial niche signals. GSCs transplanted slices were treated with the anti-mitotic drug temozolomide as proof-of-principle of the utility in modelling responses to existing treatments. Thus, engraftment of mouse or human GSCs onto whole brain coronal organotypic brain slices provides a convenient experimental model for studies of GSC-host interactions and preclinical testing of candidate therapeutic agents.

cancer biology↗