mTORC1-dependent AMD1 regulation sustains polyamine metabolism in prostate cancer

Menée à l'aide de modèles murins et d'échantillons prélevés sur des patients atteints d'un cancer de la prostate, cette étude met en évidence des mécanismes par lesquels, en lien avec une activation de la signalisation mTORC1, l'enzyme AMD1 régule le métabolisme des polyamines et favorise la prolifération des cellules cancéreuses

Résumé en anglais

Activation of the PTEN–PI3K–mTORC1 pathway consolidates metabolic programs that sustain cancer cell growth and proliferation. Here we show that mechanistic target of rapamycin complex 1 (mTORC1) regulates polyamine dynamics, a metabolic route that is essential for oncogenicity. By using integrative metabolomics in a mouse model and human biopsies of prostate cancer, we identify alterations in tumours affecting the production of decarboxylated S-adenosylmethionine (dcSAM) and polyamine synthesis. Mechanistically, this metabolic rewiring stems from mTORC1-dependent regulation of S-adenosylmethionine decarboxylase 1 (AMD1) stability. This novel molecular regulation is validated in mouse and human cancer specimens. AMD1 is upregulated in human prostate cancer with activated mTORC1. Conversely, samples from a clinical trial with the mTORC1 inhibitor everolimus5 exhibit a predominant decrease in AMD1 immunoreactivity that is associated with a decrease in proliferation, in line with the requirement of dcSAM production for oncogenicity. These findings provide fundamental information about the complex regulatory landscape controlled by mTORC1 to integrate and translate growth signals into an oncogenic metabolic program.