The tumor suppressor protein BRCA1 has been shown to enhance p53 transcription, whereas activated p53 represses BRCA1 transcription. To further understand the functional interaction of these proteins, we investigated the role of BRCA1 in p53-induced phenotypes. We found that BRCA1 when subjected to forced expression acts synergistically with wild-type p53, resulting in irreversible growth arrest, as shown by VhD mouse fibroblast cells expressing a temperature-sensitive mutant of p53. Furthermore, reintroduction of both BRCA1 and p53 into BRCA1(-/-)/p53(-/-) mouse embryonic fibroblasts markedly increased the senescence phenotype compared to that induced by p53 alone. In particular, we found that BRCA1 expression attenuated p53-mediated cell death in response to gamma-irradiation. Moreover, microarray screening of 11 000 murine genes demonstrated that a set of genes upregulated by p53 is enhanced by coexpression of BRCA1 and p53, suggesting that BRCA1 and p53 exert a promoter selectivity leading to a specific phenotype. Taken together, our results provide evidence that BRCA1 is involved in p53-mediated growth suppression rather than apoptosis.
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http://dx.doi.org/10.1038/sj.onc.1206439 | DOI Listing |
Clin Transl Oncol
January 2025
Inflammation and Cancer Biology Laboratory, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, 784028, India.
Globally, breast and ovarian cancers are major health concerns in women and account for significantly high cancer-related mortality rates. Dysregulations and mutations in genes like TP53, BRCA1/2, KRAS and PTEN increase susceptibility towards cancer. Here, we discuss the impact of mutations in the key regulatory gene, TP53 and polymorphisms in its negative regulator MDM2 which are reported to accelerate cancer progression.
View Article and Find Full Text PDFCureus
December 2024
Department of Biochemistry, Era's Lucknow Medical College and Hospital, Era University, Lucknow, IND.
Background: Curcumin (Cur) is a polyphenol phyto-compound found in turmeric () that inhibits tumorigenesis by introducing apoptosis and restricting cell survival and proliferation. This in vitro research article focuses on the pharmacodynamic interactions of Cur combined with the commercial drug doxorubicin (Doxo) to enhance the cytotoxicity of Doxo at lower doses against triple-negative breast cancer cells (MDA-MB-231) with the chemo-protective effect against normal HEK293 cells. In this study, we observed the dose-dependent cytotoxicity, increased reactive oxygen species (ROS) generation, and increased chromatin condensation in combination doses compared to single doses.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Infectious Diseases and Pathobiology, Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland.
Taxanes are frequently used anticancer drugs known to kill tumor cells by inducing mitotic aberrations and segregation defects. A defining feature of specific cancers, notably triple-negative breast cancer (TNBC) and particularly those deficient in BRCA1, is chromosomal instability (CIN). Here, we focused on understanding the mechanisms of docetaxel-induced cytotoxicity, especially in the context of BRCA1-deficient TNBC.
View Article and Find Full Text PDFBMC Cancer
December 2024
Department of Surgery, Aga Khan University Hospital, P.O. Box 3500, Stadium Road, Karachi, 74800, Pakistan.
Cell Oncol (Dordr)
December 2024
Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA.
BRCA1 (Breast Cancer 1) is a tumor suppressor gene with a role in DNA repair by Homologous Recombination (HR), and maintenance of genomic stability that is frequently investigated in breast, prostate, and ovarian cancers. BRCA1 mutations or dysregulation in glioblastoma can lead to impaired DNA repair mechanisms, resulting in tumor progression and resistance to standard therapies. Several studies have shown that BRCA1 expression is altered, albeit rarely, in glioblastoma, leading to poor prognosis and increased tumor aggressiveness.
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