We investigated the mechanisms by which TAp73 beta and dominant-negative p73 (Delta Np73) regulate apoptosis. TAp73 beta transactivated the CD95 gene via the p53-binding site in the first intron. In addition, TAp73 beta induced expression of proapoptotic Bcl-2 family members and led to apoptosis via the mitochondrial pathway. Endogenous TAp73 was upregulated in response to DNA damage by chemotherapeutic drugs. On the contrary, DeltaNp73 conferred resistance to chemotherapy. Inhibition of CD95 gene transactivation was one mechanism by which DeltaNp73 functionally inactivated the tumor suppressor action of p53 and TAp73 beta. Concomitantly, DeltaNp73 inhibited apoptosis emanating from mitochondria. Thus, DeltaNp73 expression in tumors selects against both the death receptor and the mitochondrial apoptosis activity of TAp73 beta. The importance of these data is evidenced by our finding that upregulation of DeltaNp73 in hepatocellular carcinoma patients correlates with reduced survival. Our data indicate that Delta Np73 is an important gene in hepatocarcinogenesis and a relevant prognostic factor.
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http://dx.doi.org/10.1038/sj.cdd.4401774 | DOI Listing |
Biomedicines
January 2024
First Department of Medicine, University Hospital Schleswig-Holstein (UKSH), Campus Lübeck, 23538 Lübeck, Germany.
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer type characterized by a marked desmoplastic tumor stroma that is formed under the influence of transforming growth factor (TGF)-β. Data from mouse models of pancreatic cancer have revealed that transcriptionally active p73 (TAp73) impacts the TGF-β pathway through activation of Smad4 and secretion of biglycan (Bgn). However, whether this pathway also functions in human PDAC cells has not yet been studied.
View Article and Find Full Text PDFCancers (Basel)
July 2023
First Department of Medicine, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany.
Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease due to early metastatic spread, late diagnosis and the lack of efficient therapies. A major driver of cancer progression and hurdle to successful treatment is transforming growth factor (TGF)-β. Recent data from pancreatic cancer mouse models showed that transcriptionally active p73 (TAp73), a p53 family member, inhibits tumor progression through promoting tumor suppressive canonical TGF-β/Smad signaling, while preventing non-canonical TGF-β signaling through extracellular signal-regulated kinases (ERK)1/2.
View Article and Find Full Text PDFMol Biol (Mosk)
April 2022
Department of Biostatistics and Medical Informatics, Faculty of Medicine, Ege University, Izmir, 35100 Turkey.
The transcription factor p73 is a member of the p53 tumor suppressor gene family and one of the key regulators of apoptosis. TP73 gene encodes two protein isoforms classes with diverse functions, TAp73 and DNp73, and TAp73 expression in tumor tissues is altered. Unlike the TP53 gene, TP73 is not mutated in cancers.
View Article and Find Full Text PDFPLoS Genet
May 2021
Cancer and Stem Cell Epigenetics Section, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America.
The CBFB gene is frequently mutated in several types of solid tumors. Emerging evidence suggests that CBFB is a tumor suppressor in breast cancer. However, our understanding of the tumor suppressive function of CBFB remains incomplete.
View Article and Find Full Text PDFCell Cycle
July 2020
Medical Research Council, Toxicology Unit, Department of Pathology, Cambridge University, Cambridge, UK.
The p53 family transcriptional factor p73 plays a pivotal role in development. Ablation of p73 results in severe neurodevelopmental defects, chronic infections, inflammation and infertility. In addition to this, Trp73 mice display severe alteration in the ciliated epithelial lining and the full-length -terminal isoform TAp73 has been implicated in the control of multiciliogenesis transcriptional program.
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