Article

Phospho-MED1-enhanced UBE2C locus looping drives castration-resistant prostate cancer growth

Department of Molecular and Cellular Biochemistry and the Comprehensive Cancer Center, The Ohio State University College of Medicine, Columbus, OH, USA.
The EMBO Journal (Impact Factor: 10.75). 06/2011; 30(12):2405-19. DOI: 10.1038/emboj.2011.154
Source: PubMed

ABSTRACT The UBE2C oncogene is overexpressed in many types of solid tumours including the lethal castration-resistant prostate cancer (CRPC). The underlying mechanisms causing UBE2C gene overexpression in CRPC are not fully understood. Here, we show that CRPC-specific enhancers drive UBE2C overexpression in both AR-negative and -positive CRPC cells. We further show that co-activator MED1 recruitment to the UBE2C enhancers is required for long-range UBE2C enhancer/promoter interactions. Importantly, we find that the molecular mechanism underlying MED1-mediated chromatin looping involves PI3K/AKT phosphorylated MED1-mediated recruitment of FoxA1, RNA polymerase II and TATA binding protein and their subsequent interactions at the UBE2C locus. MED1 phosphorylation leads to UBE2C locus looping, UBE2C gene expression and cell growth. Our results not only define a causal role of a post-translational modification (phosphorylation) of a co-activator (MED1) in forming or sustaining an active chromatin structure, but also suggest that development of specific therapies for CRPC should take account of targeting phosphorylated MED1.

0 Followers
 · 
131 Views
  • Source
    • "miR-96 expression was also associated with BCR, indicating its potential role as a prognostic biomarker. Notably, negative modulation of miR-205 in recurrent samples was confirmed also by Hulf et al. [55] who also demonstrated that this microRNA can impair cell viability of cancer cells through modulation of MED1 which has been correlated with castration-resistance acquisition [56]. Due to the high number of studies demonstrating the downregulation of miR-205 in patient-derived samples, the role of miR-205 in PCa biology has been further investigated in basic research, and recent reports demonstrated that this microRNA exerts its tumor-suppressive functions directly inhibiting the expression of the AR and its downstream signaling cascade, c-SRC oncogene and the antiapoptotic Bcl-2 protein [57] [58] [59] [60]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Prostate cancer (PCa) is one of the leading causes of cancer-related death in men. Despite considerable advances in prostate cancer early detection and clinical management, validation of new biomarkers able to predict the natural history of tumor progression is still necessary in order to reduce overtreatment and to guide therapeutic decisions. MicroRNAs are endogenous noncoding RNAs which offer a fast fine-tuning and energy-saving mechanism for posttranscriptional control of protein expression. Growing evidence indicate that these RNAs are able to regulate basic cell functions and their aberrant expression has been significantly correlated with cancer development. Therefore, detection of microRNAs in tumor tissues and body fluids represents a new tool for early diagnosis and patient prognosis prediction. In this review, we summarize current knowledge about microRNA deregulation in prostate cancer mainly focusing on the different clinical aspects of the disease. We also highlight the potential roles of microRNAs in PCa management, while also discussing several current challenges and needed future research.
    BioMed Research International 09/2014; 2014:146170. DOI:10.1155/2014/146170 · 2.71 Impact Factor
  • Source
    • "The predicted transcription factors binding sites at the UBE2C promoter have been identified, including binding sites for C-Rel, Pax-2, Pax-2a, CP1A, CP1C (GeneCard: GC20P044442), NF-1, SRF, TGIF, Meis-1 and c-Myc (Hao et al., 2012). UBE2C can be an androgen receptor target gene in prostate cancer cells and is responsive to hyperphosphorylated MED1 (androgen receptor co-activator mediator-1) in androgen receptor negative prostate cancer cells (Chen et al., 2011). UBE2C expression can also be induced by the estrogen receptor in breast cancer cells (Wang et al., 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The ubiquitin-conjugating enzymes 2C (UBE2C) is an integral component of the ubiquitin proteasome system. UBE2C consists of a conserved core domain containing the catalytic Cys residue and an N-terminal extension. The core domain is required for ubiquitin adduct formation by interacting with the ubiquitin-fold domain in the E1 enzyme, and contributes to the E3 enzyme binding. UBE2C N-terminal extension regulates E3 enzyme activity as a part of an intrinsic inhibitory mechanism. UBE2C is required for the destruction of mitotic cyclins and securin, which are essential for spindle assembly checkpoint and mitotic exit. The UBE2C mRNA and/or protein levels are aberrantly increased in many cancer types with poor clinical outcomes. Accumulation of UBE2C stimulates cell proliferation and anchorage-independent growth. UBE2C transgenic mice are prone to develop spontaneous tumors and carcinogen-induced tumor with evidence of chromosome aneuploidy.
    The international journal of biochemistry & cell biology 12/2013; DOI:10.1016/j.biocel.2013.11.023 · 4.24 Impact Factor
  • Source
    • "In agreement with these findings, the Wang group has shown that expression of the androgen receptor oncogene target UBE2C was sensitive to MED1 phosphorylation at T1032 (Chen et al., 2011). MED1 phosphorylation was linked to more stable and active PICs; furthermore, UBE2C expression correlated with chromatin loop formation (linking the enhancer and promoter), and this architectural change was dependent on MED1 phosphorylation by the PI3K/AKT pathway. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Abstract The Mediator complex is a multi-subunit assembly that appears to be required for regulating expression of most RNA polymerase II (pol II) transcripts, which include protein-coding and most non-coding RNA genes. Mediator and pol II function within the pre-initiation complex (PIC), which consists of Mediator, pol II, TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH and is approximately 4.0 MDa in size. Mediator serves as a central scaffold within the PIC and helps regulate pol II activity in ways that remain poorly understood. Mediator is also generally targeted by sequence-specific, DNA-binding transcription factors (TFs) that work to control gene expression programs in response to developmental or environmental cues. At a basic level, Mediator functions by relaying signals from TFs directly to the pol II enzyme, thereby facilitating TF-dependent regulation of gene expression. Thus, Mediator is essential for converting biological inputs (communicated by TFs) to physiological responses (via changes in gene expression). In this review, we summarize an expansive body of research on the Mediator complex, with an emphasis on yeast and mammalian complexes. We focus on the basics that underlie Mediator function, such as its structure and subunit composition, and describe its broad regulatory influence on gene expression, ranging from chromatin architecture to transcription initiation and elongation, to mRNA processing. We also describe factors that influence Mediator structure and activity, including TFs, non-coding RNAs and the CDK8 module.
    Critical Reviews in Biochemistry and Molecular Biology 10/2013; 48(6). DOI:10.3109/10409238.2013.840259 · 5.81 Impact Factor
Show more

Preview

Download
3 Downloads
Available from