Biology subjects

Possemato, R.

Publications and source records attributed to Possemato, R..

3 recordsLinked to original sources

bioRxiv2023

The expression profile and tumorigenic mechanisms of CD97 (ADGRE5) in glioblastoma render it a targetable vulnerability

Glioblastoma (GBM) is the most common and aggressive primary brain malignancy. Adhesion G protein-coupled receptors (aGPCRs) have attracted interest for their functional role in gliomagenesis and their potential as treatment targets. To identify therapeutically targetable opportunities among aGPCR family members in unbiased fashion, we analyzed expression levels of all aGPCRs in GBM and non-neoplastic brain tissue. Using bulk and single cell transcriptomic and proteomic data, we show that CD97 (ADGRE5), an aGPCR previously implicated in GBM pathogenesis, is the most promising aGPCR target in GBM, by virtue of its abundance in all GBM tumors and its de novo expression profile in GBM compared to normal brain tissue and neural progenitors. CD97 knockdown or knockout significantly reduces the tumor initiation capacity of patient-derived GBM cultures (PDGC) in vitro and in vivo. Transcriptomic and metabolomic data from PDGCs suggest that CD97 promotes glycolytic metabolism. The oncogenic and metabolic effects of CD97 are mediated by the MAPK pathway. Activation of MAPK signaling depends on phosphorylation of the cytosolic C-terminus of CD97 and recruitment of {beta}-arrestin. Using single-cell RNA-sequencing and biochemical assays, we demonstrate that THY1/CD90 is the most likely CD97 ligand in GBM. Lastly, we show that targeting of PDGCs with an anti-CD97 antibody-drug conjugate in vitro selectively kills tumor cells but not human astrocytes or neural stem cells. Our studies identify CD97 as an important regulator of tumor metabolism in GBM, elucidate mechanisms of receptor activation and signaling, and provide strong scientific rationale for developing biologics to target it for therapeutic purposes.

cancer biology↗

bioRxiv2022

Comprehensive Analysis of Regenerative and Transformed Liver Reveals Distinct, Early Metabolic Alterations in Cancer

Alterations in cellular metabolism represent an important response to proliferative signals in both normal and transformed tissues. The benign proliferative process of liver regeneration after partial hepatectomy offers insight into homeostatic mechanisms to control liver mass, which are disrupted in liver disease induced by viral factors, alcohol, or associated with obesity. Moreover, successful targeting of cancer depends on the identification of genes and pathways that are selectively activated in the transformed state. Here, we present a differential transcriptomic and metabolomic analysis of benign proliferative and transformed liver, including associated plasma metabolite and lipid species. Using partial hepatectomy-induced liver regeneration and diethylnitrosamine (DEN) induced carcinogenesis, we identify and analyze alterations specific to multiple regenerative and transformed tissue states. Transcriptomics and LC/MS based metabolite profiling reveal fatty acid import and storage are specifically rewired during liver regeneration in a time dependent manner, a phenomenon not observed in liver tumors. In contrast, liver tumors exhibit preferential activation of numerous metabolic pathways, including glycolysis, serine biosynthesis, and polyamine metabolism. Alterations in serine metabolism occur at the earliest detectable stages in tumorigenesis and promote survival upon serine restriction. These data demonstrate that transformation-induced alterations in metabolism are distinct from those observed in normal regenerative cell division, which may be used to identify transformation-specific liabilities.

cancer biology↗

bioRxiv2019

Selective metabolic redundancy of Gpi1 allows for specific inhibition of inflammatory Th17 cells

SummaryTargeting glycolysis has been considered therapeutically intractable owing to its essential housekeeping role. However, the context-dependent requirement for individual glycolytic steps has not been fully explored. We show that CRISPR-mediated targeting of glycolysis in T cells in mice results in global loss of Th17 cells, whereas deficiency of the glycolytic enzyme glucose phosphate isomerase (Gpi1) selectively eliminates inflammatory encephalitogenic and colitogenic Th17 cells, without substantially affecting homeostatic microbiota-specific Th17 cells. In homeostatic Th17 cells, partial blockade of glycolysis upon Gpi1 inactivation was compensated by pentose phosphate pathway flux and increased mitochondrial respiration. In contrast, inflammatory Th17 cells experience a hypoxic microenvironment known to limit mitochondrial respiration, which is incompatible with loss of Gpi1. Our study suggests that inhibiting glycolysis by targeting Gpi1 could be an effective therapeutic strategy with minimum toxicity for Th17-mediated autoimmune diseases, and, more generally, that metabolic redundancies can be exploited for selective targeting of disease processes.

immunology↗