Calzado, M. A. | bioRxiv Science

bioRxiv2025

Gliomas phenocopy an inborn error of metabolism to drive neuronal activity and tumor growth

The metabolic hallmarks of high-grade glioma (HGG) are not fully understood. Human brain tissue metabolomics revealed that the creatine synthesis pathway intermediate guanidinoacetate (GAA) accumulated [~]100-fold in HGGs relative to controls, which was caused by imbalanced activities of enzymes in this pathway. Glioma cells secreted GAA rather than using it to produce creatine, implicating an unexpected function. GAA accumulates in GAMT deficiency, an inborn error of metabolism, and elevates neuronal excitability. Neuronal excitability is also increased in glioma and drives tumor growth through neuron-glioma interactions. We hypothesized that glioma-generated GAA excites surrounding neurons. Indeed, GAA induced neuronal hyperactivity by activating GABAA receptors and causing depolarizing GABA currents in glioma-associated neurons with dysregulated chloride homeostasis. Depleting tumoral GAA decreased electrochemical activity, neuron-glioma interactions, and tumor aggressiveness. Our findings unveil a new mechanism linking cancer metabolism with cancer neuroscience and leverage human genetics to nominate GAA synthesis as a target in gliomas.

cancer biology↗

bioRxiv2021

USP28 enables oncogenic transformation of respiratory cells and its inhibition potentiates molecular therapy targeting mutant EGFR, BRAF and PI3K.

Oncogenic transformation of lung epithelial cells is a multi-step process, frequently starting with the inactivation of tumor suppressors and subsequent activating mutations in proto-oncogenes, such as members of the PI3K or MAPK family. Cells undergoing transformation have to adjust to changes, such as metabolic requirements. This is achieved, in part, by modulating the protein abundance of transcription factors, which manifest these adjustments. Here, we report that the deubiquitylase USP28 enables oncogenic reprogramming by regulating the protein abundance of proto-oncogenes, such as c-JUN, c-MYC, NOTCH and {Delta}NP63, at early stages of malignant transformation. USP28 is increased in cancer compared to normal cells due to a feed-forward loop, driven by increased amounts of oncogenic transcription factors, such as c-MYC and c-JUN. Irrespective of oncogenic driver, interference with USP28 abundance or activity suppresses growth and survival of transformed lung cells. Furthermore, inhibition of USP28 via a small molecule inhibitor reset the proteome of transformed cells towards a pre-malignant state, and its inhibition cooperated with clinically established compounds used to target EGFRL858R, BRAFV600E or PI3KH1047R driven tumor cells. Targeting USP28 protein abundance already at an early stage via inhibition of its activity therefore is a feasible strategy for the treatment of early stage lung tumours and the observed synergism with current standard of care inhibitors holds the potential for improved targeting of established tumors.

cancer biology↗

bioRxiv2019

Tetrahydrocannabinolic Acid A (THCA-A) Reduces Adiposity And Prevents Metabolic Disease Caused By Diet-Induced Obesity

Cannabis has remarkable therapeutic potential, but its clinical use is limited by the psychotropic activity of {Delta}9-tetrahydrocannabinol ({Delta}9-THC). Surprisingly, the biological profile of the non-narcotic native precursor of {Delta}9-THC ({Delta}9-THC acid A, {Delta}9-THCA-A) is still largely unexplored. We present evidence that {Delta}9-THCA-A is a partial and selective PPAR{gamma} modulator, endowed with lower adipogenic activity than the full PPAR{gamma} agonist rosiglitazone (RGZ) and with an enhanced osteoblastogenic activity in human mesenchymal stem cells. Docking and in vitro functional assays indicated that {Delta}9-THCA-A binds to and activates PPAR{gamma} by acting at both the canonical and the alternative sites of the ligand-binding domain. Transcriptomic signatures at inguinal white adipose tissue (iWAT) from mice treated with {Delta}9-THCA-A confirmed its mode of action on PPAR{gamma}. Administration of {Delta}9-THCA-A in a mouse model of high fat diet (HFD)-induced obesity significantly reduced fat mass and body weight gain, markedly ameliorating glucose intolerance and insulin resistance, and largely preventing liver steatosis, adipogenesis and macrophage infiltration in fat tissues. Additionally, immunohistochemistry, transcriptomic, and plasma biomarker analyses showed that treatment with {Delta}9-THCA-A caused browning of iWAT and displayed potent anti-inflammatory actions in HFD mice. Altogether, our data validate the potential of {Delta}9-THCA-A as a low adipogenic PPAR{gamma} agonist, capable of substantially improving the symptoms of obesity-associated metabolic syndrome and inflammation. These findings suggest that {Delta}9-THCA-A, and perhaps non-decarboxylated Cannabis sativa extracts, are worth considering for addition to our inventory of cannabis medicines.\n\nSIGNIFICANCE STATEMENTThe medicinal use of Cannabis is gaining momentum, despite the adverse psychotropic effects of {Delta}9-THC, the decarboxylation product of its naturally occurring and non-psychotropic precursor {Delta}9-THCA-A. We present evidence that {Delta}9-THCA-A is a partial ligand agonist of PPAR{gamma} with lower adipogenic activity compared to the full PPAR{gamma} agonist rosiglitazone (RGZ). Moreover, chronic administration of {Delta}9-THCA-A in a mouse model of high fat diet (HFD)-induced obesity significantly reduced body weight gain and fat mass, improved glucose intolerance and insulin resistance, and prevented liver steatosis and macrophage infiltration in fat tissues, additionally inducing white adipose tissue browning. Collectively, these observations qualify {Delta}9-THCA-A, a compound devoid of psychotropic effects, as an efficacious pharmacological agent to manage metabolic syndrome and obesity-associated inflammation.\n\nHighlights- {Delta}9-THCA-A is a partial PPAR{gamma} ligand agonist with low adipogenic activity\n- {Delta}9-THCA-A enhances osteoblastogenesis in bone marrow derived mesenchymal stem cells.\n- {Delta}9-THCA-A reduces body weight gain, fat mass, and liver steatosis in HFD-fed mice\n- {Delta}9-THCA-A improves glucose tolerance, insulin sensitivity, and insulin profiles in vivo\n- {Delta}9-THCA-A induces browning of iWAT and has a potent anti-inflammatory activity

pharmacology and toxicology↗