The methylthioadenosine phosphorylase (MTAP) gene is a tumour suppressor gene, located on chromosome 9p21, 100 kb telomeric of the p15 and p16 genes, which are often deleted in tumor cells. The role of MTAP protein expression in the genesis of cutaneous squamous cell carcinoma (SCC) is currently not known. In a previous study we have shown the frequent occurrence of allelic imbalance/loss of heterozygosity (AI/LOH) in cutaneous SCCs using AI/LOH markers flanking the p15, p16, and MTAP genes and demonstrated reduction in p15 and p16 protein expression in comparison to normal human skin. The present study is a continuation to our previous studies, aimed at determining possible roles played by MTAP protein expression in the genesis of cutaneous SCC. The expression of MTAP protein was detected using immunohistochemical approach in 109 micro array cutaneous SCC and 20 normal human skin tissue samples. The expression of MTAP was not significantly different in the cutaneous SCC cases as compared with normal human skin. This may indicate that MTAP protein expression does not contribute to the genesis of cutaneous SCC.
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J Med Chem
January 2025
Insilico Medicine Shanghai Ltd, Suite 901, Tower C, Changtai Plaza, 2889 Jinke Road, Pudong New District, Shanghai 201203, China.
Protein arginine methyltransferase 5 (PRMT5), which catalyzes the symmetric dimethylation of arginine residues on target proteins, plays a critical role in gene expression regulation, RNA processing, and signal transduction. Aberrant PRMT5 activity has been implicated in cancers and other diseases, making it a potential therapeutic target. Here, we report the discovery of a methylthioadenosine (MTA) cooperative PRMT5 inhibitor.
View Article and Find Full Text PDFCells
December 2024
Department of Internal Medicine III, University Hospital Regensburg, 93053 Regensburg, Germany.
Metabolite accumulation in the tumor microenvironment fosters immune evasion and limits the efficiency of immunotherapeutic approaches. Methylthioadenosine phosphorylase (MTAP), which catalyzes the degradation of 5'-deoxy-5'methylthioadenosine (MTA), is downregulated in many cancer entities. Consequently, MTA accumulates in the microenvironment of MTAP-deficient tumors, where it is known to inhibit tumor-infiltrating T cells and NK cells.
View Article and Find Full Text PDFHomozygous MTAP deletion occurs in ~15% of cancers, making them vulnerable to decreases in the concentration of S-adenosylmethionine (SAM). AG-270/S095033 is an oral, potent, reversible inhibitor of methionine adenosyltransferase 2 A (MAT2A), the enzyme primarily responsible for the synthesis of SAM. We report results from the first-in-human, phase 1 trial of AG-270/S095033 as monotherapy in patients with advanced malignancies (ClinicalTrials.
View Article and Find Full Text PDFCancer Med
December 2024
School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, Shandong, People's Republic of China.
Background: Methylthioadenosine phosphorylase (MTAP) and protein arginine methyltransferase 5 (PRMT5) are considered to be a synthetic lethal pair of targets, due to the fact that deletion of MTAP leads to massive production of methylthioadenosine (MTA) decreasing the activity of PRMT5. In vitro and in vivo experiments have demonstrated that MRTX1719, a small molecule that selectively binds PRMT5/MTA complex, significantly inhibits the proliferation of MTAP-deficient tumors and has a weak toxic effect on normal cells. However, it has been reported that MTAP-deleted tumors did not significantly accumulate MTA in vivo due to metabolism of MTA by MTAP-expressing stroma, which might lead to a diminished anti-cancer effect of MRTX1719.
View Article and Find Full Text PDFAnn Oncol
December 2024
Early Drug Development for Innovative Therapies, European Institute of Oncology IRCCS, Milan; Department of Oncology and Haemato-Oncology, University of Milano, Milan, Italy. Electronic address:
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