Hijacking the E3 Ubiquitin Ligase Cereblon to Efficiently Target BRD4

Repression of the Antioxidant NRF2 Pathway in Premature Aging.

Bromodomain and extraterminal domain (BET) proteins are epigenetic readers that regulate gene expression and are involved in cancer pathogenesis. Over the last years, several BET inhibitors have been developed and clinically tested. Results from the first clinical trials show limited single-agent activity in a small subset of patients with hematologic malignancies and in NUT carcinoma. Adverse events have been observed and may limit treatment compliance. Here, we review the preclinical rationale for targeting BET proteins in cancer and the preliminary results from clinical trials, and outline future directions for the use of BET inhibitors as antitumor agents. Significance: BET inhibitors represent a new class of anticancer agents. Results from the first clinical trials confirm the antitumor potential of BET inhibitors, but their efficacy as single agents seems to be limited. Based on preclinical data, combination therapies with other anticancer agents and the development of a new generation of compounds may open new possibilities for targeting BET proteins as effective anticancer strategies. Cancer Discov; 8(1); 24–36. ©2017 AACR.

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BET Proteins as Targets for Anticancer Treatment.

Oncogene-induced senescence is a potent barrier to tumorigenesis that limits cellular expansion following certain oncogenic events. Senescent cells display a repressive chromatin configuration thought to stably silence proliferation-promoting genes, while simultaneously activating an unusual form of immune surveillance involving a secretory program referred to as the senescence-associated secretory phenotype (SASP). Here we demonstrate that senescence also involves a global remodeling of the enhancer landscape with recruitment of the chromatin reader BRD4 to newly activated super-enhancers adjacent to key SASP genes. Transcriptional profiling and functional studies indicate that BRD4 is required for the SASP and downstream paracrine signaling. Consequently, BRD4 inhibition disrupts immune cell mediated targeting and elimination of premalignant senescent cells in vitro and in vivo. Our results identify a critical role for BRD4-bound super-enhancers in senescence immune surveillance and in the proper execution of a tumor-suppressive program.

/pdf/brd4-connects-enhancer-remodeling-to-senescence-immune-2ykohk3k6r.pdf

BRD4 Connects Enhancer Remodeling to Senescence Immune Surveillance

Epigenetic mechanisms have emerged as key players in cancer development which affect cellular states at multiple stages of the disease. During carcinogenesis, alterations in chromatin and DNA methylation resulting from genetic lesions unleash cellular plasticity and favor oncogenic cellular reprogramming. At later stages, during cancer growth and progression, additional epigenetic changes triggered by interaction with the microenvironment modulate cancer cell phenotypes and properties, and shape tumor architecture. We review here recent advances highlighting the interplay between epigenetics, genetics, and cell-to-cell signaling in cancer, with particular emphasis on mechanisms relevant for cancer stem cell formation (CSC) and function.

Epigenetics and Cancer Stem Cells: Unleashing, Hijacking, and Restricting Cellular Plasticity

https://www.cell.com/cell-reports/pdf/S2211-1247(14)00761-X.pdf

Elke Markert

Papers

Transformation resistance in a premature aging disorder identifies a tumor-protective function of BRD4.