The tumor suppressor activity induced by adenovirus-mediated BRCA1 overexpression is not restricted to breast cancers.

The BRCA1 (breast cancer 1) breast cancer susceptibility gene is recognized as responsible for most familial breast and ovarian cancers and is suggested to be a tissue-specific tumor suppressor gene. In this report, we investigated the tissue specificity of tumor inhibitory activities induced by a recombinant adenovirus coding for wild-type BRCA1 (wtAdBRCA1). We demonstrated a pronounced in vitro antiproliferative effect on H1299 lung and HT29 colon cells upon infection with AdBRCA1.

A subset of ATM- and ATR-dependent phosphorylation events requires the BRCA1 protein.

BRCA1 is a central component of the DNA damage response mechanism and defects in BRCA1 confer sensitivity to a broad range of DNA damaging agents. BRCA1 is required for homologous recombination and DNA damage-induced S and G(2)/M phase arrest. We show here that BRCA1 is required for ATM- and ATR-dependent phosphorylation of p53, c-Jun, Nbs1 and Chk2 following exposure to ionizing or ultraviolet radiation, respectively, and is also required for ATM phosphorylation of CtIP.

BRCA1 supports XIST RNA concentration on the inactive X chromosome.

BRCA1, a breast and ovarian tumor suppressor, colocalizes with markers of the inactive X chromosome (Xi) on Xi in female somatic cells and associates with XIST RNA, as detected by chromatin immunoprecipitation. Breast and ovarian carcinoma cells lacking BRCA1 show evidence of defects in Xi chromatin structure. Reconstitution of BRCA1-deficient cells with wt BRCA1 led to the appearance of focal XIST RNA staining without altering XIST abundance.

Constitutive association of BRCA1 and c-Abl and its ATM-dependent disruption after irradiation.

BRCA1 plays an important role in mechanisms of response to double-strand breaks, participating in genome surveillance, DNA repair, and cell cycle checkpoint arrests. Here, we identify a constitutive BRCA1-c-Abl complex and provide evidence for a direct interaction between the PXXP motif in the C terminus of BRCA1 and the SH3 domain of c-Abl. Following exposure to ionizing radiation (IR), the BRCA1-c-Abl complex is disrupted in an ATM-dependent manner, which correlates temporally with ATM-dependent phosphorylation of BRCA1 and ATM-dependent enhancement of the tyrosine kinase activity of c-Abl.

BRCA1 carries tumor suppressor activity distinct from that of p53 and p21.

The loss of BRCA1 function appears as an essential step in breast and ovarian epithelial cells oncogenesis and is consistent with the concept that BRCA1 acts as a tumor suppressor gene. However, the mechanism underlying this activity is not understood. In 1996, a retroviral vector was used for BRCA1 delivery to demonstrate that the transfer of BRCA1 inhibits breast and ovarian cancer cell growth.

BRCA1 and BRCA2 are necessary for the transcription-coupled repair of the oxidative 8-oxoguanine lesion in human cells.

The breast and ovarian cancer susceptibility genes, BRCA1 and BRCA2, are likely to participate in DNA lesion processing. Oxidative lesions, such as 8-oxoguanine, occur in DNA after endogenous or exogenous oxidative stress. We show that deficiency for either BRCA1 or BRCA2 in human cancer cells leads to a block of the RNA polymerase II transcription machinery at the 8-oxoguanine site and impairs the transcription-coupled repair of the lesion, leading to a high mutation rate.

Gamma-rays-induced death of human cells carrying mutations of BRCA1 or BRCA2.

There is now evidence to suggest that BRCA1 and BRCA2 are involved in the response of cells to DNA damage and cell cycle checkpoint control. This report examines the death pathways of human cells with various BRCA1 and BRCA2 genotypes after exposure to gamma-rays. A lack of functional BRCA1 and BRCA2 led to defective repair of DNA double-strand breaks in irradiated cells.

A recombinant E1-deleted canine adenoviral vector capable of transduction and expression of a transgene in human-derived cells and in vivo.

Human adenovirus (HAV) serotypes 2 and 5 are commonly used as vector backbones for adenovirus-mediated gene transfer. However, HAVs were chosen as a backbone for the vectors for historical reasons and have a number of significant disadvantages when used as a shuttle for gene transfer in humans. As an initial trial to circumvent some of the shortcomings of HAV vectors, we have produced an E1-deleted canine adenovirus type 2 (CAV-2) vector for gene transfer.