Several cancer clinical trials for small molecule inhibitors of BET bromodomain proteins have been initiated. There is enthusiasm for the anti-proliferative effect of inhibiting BRD4, one of the targets of these inhibitors, which is thought to cooperate with MYC, a long-desired target for cancer therapeutics. However, no current inhibitor is selective for BRD4 among the three somatic BET proteins, which include BRD2 and BRD3; their respective functions are partially overlapping and none are functionally redundant with BRD4. Each BET protein controls distinct transcriptional pathways that are important for functions beyond cancer cell proliferation, including insulin production, cytokine gene transcription, T cell differentiation, adipogenesis and most seriously, active repression of dangerous latent viruses like HIV. BET inhibitors have been shown to reactivate HIV in human cells. Failure to appreciate that at concentrations used, no available BET inhibitor is member-selective, or to develop a sound biological basis to understand the diverse functions of BET proteins before undertaking for these clinical trials is reckless and likely to lead to adverse events. More mechanistic information from new basic science studies should enable proper focus on the most relevant cancers and define the expected side effect profiles.

The Bromodomain and ExtraTerminal (BET) proteins are epigenetic ‘readers’ of acetylated histones in chromatin and have been identified as promising therapeutic targets in diverse cancers. However, it remains unclear how individual family members participate in cancer progression, and small molecule inhibitors such as JQ1 can target functionally independent BET proteins. Here we report a signaling pathway involving BRD4 and the ligand/receptor pair Jagged1/Notch1 that sustains triple-negative breast cancer migration and invasion. BRD4, but not BRD2 or BRD3, regulated Jagged1 expression and Notch1 signaling. BRD4-selective knockdown suppressed Notch1 activity and impeded breast cancer migration and invasion. BRD4 was required for interleukin-6-stimulated, Notch1-induced migration and invasion, coupling microenvironment inflammation with cancer propagation. Moreover, in patients, BRD4 and Jagged1 expression positively correlated with the presence of distant metastases. These results identify a BRD4/Jagged1/Notch1 signaling pathway that is critical for dissemination of triple-negative breast cancer.

BSCPB with ropivacaine and clonidine improved intraoperative analgesia. BSCPB with ropivacaine or ropivaciane and clonidine was effective in reducing analgesic requirements after thyroid surgery.

Oral preoperative administration of gabapentin did not modify immediate pain management in thyroidectomy patients receiving SCPB, but prevented delayed neuropathic pain at 6 mo.

Sphingosine 1-phosphate (S1P) plays important roles in cell proliferation, differentiation or survival mainly through its surface G-protein-coupled receptors S1P1-5. Bone represents the major site of metastasis for prostate cancer (CaP) cells, which rely on bone-derived factors to support their proliferation and resistance to therapeutics. In the present work we have found that conditioned medium (CM) from the MC3T3 osteoblastic cell line or primary murine and human osteoblast-like cells, as well as co-culture with MC3T3 stimulate proliferation of CaP lines in S1P-dependent manner. In addition, osteoblastic-derived S1P induces resistance of CaP cells to therapeutics including chemotherapy and radiotherapy. When S1P release from osteoblastic cells is decreased (inhibition of SphK1, knock-down of SphK1 or the S1P transporter, Spns2 by siRNA) or secreted S1P neutralized with anti-S1P antibody, the proliferative and survival effects of osteoblasts on CaP cells are abolished. Because of the paracrine nature of the signaling, we studied the role of the S1P receptors expressed on CaP cells in the communication with S1P secreted by osteoblasts. Strategies aimed at down-regulating S1P1, S1P2 or S1P3 (siRNA, antagonists), established the exclusive role of the S1P/S1P1 signaling between osteoblasts and CaP cells. Bone metastases from CaP are associated with osteoblastic differentiation resulting in abnormal bone formation. We show that the autocrine S1P/S1P3 signaling is central during differentiation to mature osteoblasts by regulating Runx2 level, a key transcription factor involved in osteoblastic maturation. Importantly, differentiated osteoblasts exhibited enhanced secretion of S1P and further stimulated CaP cell proliferation in a S1P-dependent manner. By establishing the dual role of osteoblast-borne S1P on both osteoblastic differentiation and CaP cell proliferation and survival, we uncover the importance of S1P in the bone metastatic microenvironment, which may open a novel area of study for the treatment of CaP bone metastasis by targeting S1P.

Hypoxia promotes neovascularization, increased tumor growth, and therapeutic resistance. The transcription factor, hypoxia-inducible factor 1α (HIF-1α), has been reported as the master driver of adaptation to hypoxia. We previously identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) pathway as a new modulator of HIF-1α under hypoxia. Taking advantage of a monoclonal antibody neutralizing extracellular S1P (sphingomab), we report that inhibition of S1P extracellular signaling blocks HIF-1α accumulation and activity in several cancer cell models exposed to hypoxia. In an orthotopic xenograft model of prostate cancer, we show that sphingomab reduces hypoxia and modifies vessel architecture within 5 days of treatment, leading to increased intratumoral blood perfusion. Supporting the notion that a transient vascular normalization of tumor vessels is the mechanism by which sphingomab exerts its effects, we demonstrate that administration of the antibody for 5 days before chemotherapy is more effective at local tumor control and metastatic dissemination than any other treatment scheduling. These findings validate sphingomab as a potential new normalization agent that could contribute to successful sensitization of hypoxic tumors to chemotherapy.

Transcriptional programs in embryogenesis and cancer, such as the epithelial-to-mesenchymal transition (EMT), ensure cellular plasticity, an essential feature of carcinoma progression. As effectors of signal transduction, the bromodomain and extraterminal (BET) proteins are well suited to support plasticity because they function as co-activators or co-repressors of mammalian transcriptomes. Here, using both hormone-sensitive and triple-negative breast cancer (TNBC) model systems, we systematically altered EMT transcriptional profiles by manipulating individual BET proteins and found that BRD2 positively regulates EMT, whereas BRD3 and BRD4 repress this program. Knockdown of individual BET proteins revealed independent transcriptional networks that differed from each other and from the small-molecule pan-BET inhibitor JQ1, which previously had been misleadingly asserted to be BRD4-selective. Available small-molecule pan-BET inhibitors, proposed as antiproliferative agents in cancer clinical trials, obscure these biological differences. Transcriptional profiling reveals that individual BET proteins, inhibited separately, engage in and control EMT through unique processes. http://mcr.aacrjournals.org/content/molcanres/16/4/580/F1.large.jpg .

The inevitable progression of advanced prostate cancer to castration resistance, and ultimately to lethal metastatic disease, depends on primary or acquired resistance to conventional androgen deprivation therapy (ADT) and accumulated resistance strategies to evade androgen receptor (AR) suppression. In prostate cancer cells, AR adaptations that arise in response to ADT are not singular, but diverse, and include gene amplification, mutation, and even complete loss of receptor expression. Collectively, each of these AR adaptations contributes to a complex, heterogeneous, ADT-resistant tumor. Here, we examined prostate cancer cell lines that model common castration-resistant prostate cancer (CRPC) subtypes, each with different AR composition, and focused on novel regulators of tumor progression, the Bromodomain and Extraterminal (BET) family of proteins. We found that BRD4 regulates cell migration across all models of CRPC, regardless of aggressiveness and AR status, whereas BRD2 and BRD3 only regulate migration and invasion in less aggressive models that retain AR expression or signaling. BRD4, a coregulator of gene transcription, controls migration and invasion through transcription of AHNAK, a large scaffolding protein linked to promotion of metastasis in a diverse set of cancers. Furthermore, treatment of CRPC cell lines with low doses of MZ1, a small-molecule, BRD4-selective degrader, inhibits metastatic potential. Overall, these results reveal a novel BRD4-AHNAK pathway that may be targetable to treat metastatic CRPC (mCRPC).Implications: BRD4 functions as the dominant regulator of CRPC cell migration and invasion through direct transcriptional regulation of AHNAK, which together offer a novel targetable pathway to treat metastatic CRPC.