Send to:

Choose Destination
See comment in PubMed Commons below
Cell Death Dis. 2012 Oct 11;3:e408. doi: 10.1038/cddis.2012.142.

The retinoblastoma protein (Rb) as an anti-apoptotic factor: expression of Rb is required for the anti-apoptotic function of BAG-1 protein in colorectal tumour cells.

Author information

  • 1Cancer Research UK Colorectal Tumour Biology Research Group, School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.


Although the retinoblastoma-susceptibility gene RB1 is inactivated in a wide range of human tumours, in colorectal cancer, the retinoblastoma protein (Rb) function is often preserved and the RB locus even amplified. Importantly, we have previously shown that Rb interacts with the anti-apoptotic Bcl-2 associated athanogene 1 (BAG-1) protein, which is highly expressed in colorectal carcinogenesis. Here we show for the first time that Rb expression is critical for BAG-1 anti-apoptotic activity in colorectal tumour cells. We demonstrate that Rb expression not only increases the nuclear localisation of the anti-apoptotic BAG-1 protein, but that expression of Rb is required for inhibition of apoptosis by BAG-1 both in a γ-irradiated Saos-2 osteosarcoma cell line and colorectal adenoma and carcinoma cell lines. Further, consistent with the fact that nuclear BAG-1 has previously been shown to promote cell survival through increasing nuclear factor (NF)-κB activity, we demonstrate that the ability of BAG-1 to promote NF-κB activity is significantly inhibited by repression of Rb expression. Taken together, data presented suggest a novel function for Rb, promoting cell survival through regulating the function of BAG-1. As BAG-1 is highly expressed in the majority of colorectal tumours, targeting the Rb-BAG-1 complex to promote apoptosis has exciting potential for future therapeutic development.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Nature Publishing Group Icon for PubMed Central
    Loading ...
    Write to the Help Desk