NPEPPS Is a Druggable Driver of Platinum Resistance.

There is an unmet need to improve the efficacy of platinum-based cancer chemotherapy, which is used in primary and metastatic settings in many cancer types. In bladder cancer, platinum-based chemotherapy leads to better outcomes in a subset of patients when used in the neoadjuvant setting or in combination with immunotherapy for advanced disease. Despite such promising results, extending the benefits of platinum drugs to a greater number of patients is highly desirable. Using the multiomic assessment of cisplatin-responsive and -resistant human bladder cancer cell lines and whole-genome CRISPR screens, we identified puromycin-sensitive aminopeptidase (NPEPPS) as a driver of cisplatin resistance. NPEPPS depletion sensitized resistant bladder cancer cells to cisplatin in vitro and in vivo. Conversely, overexpression of NPEPPS in sensitive cells increased cisplatin resistance. NPEPPS affected treatment response by regulating intracellular cisplatin concentrations. Patient-derived organoids (PDO) generated from bladder cancer samples before and after cisplatin-based treatment, and from patients who did not receive cisplatin, were evaluated for sensitivity to cisplatin, which was concordant with clinical response. In the PDOs, depletion or pharmacologic inhibition of NPEPPS increased cisplatin sensitivity, while NPEPPS overexpression conferred resistance. Our data present NPEPPS as a druggable driver of cisplatin resistance by regulating intracellular cisplatin concentrations. SIGNIFICANCE: Targeting NPEPPS, which induces cisplatin resistance by controlling intracellular drug concentrations, is a potential strategy to improve patient responses to platinum-based therapies and lower treatment-associated toxicities.

Inhibition of the CCL2 receptor, CCR2, enhances tumor response to immune checkpoint therapy.

Immunotherapies targeting the PD-1/PD-L1 axis are now a mainstay in the clinical management of multiple cancer types, however, many tumors still fail to respond. CCL2 is highly expressed in various cancer types and has been shown to be associated with poor prognosis. Inhibition or blockade of the CCL2/CCR2 signaling axis has thus been an area of interest for cancer therapy. Here we show across multiple murine tumor and metastasis models that CCR2 antagonism in combination with anti-PD-1 therapy leads to sensitization and enhanced tumor response over anti-PD-1 monotherapy. We show that enhanced treatment response correlates with enhanced CD8+ T cell recruitment and activation and a concomitant decrease in CD4+ regulatory T cell. These results provide strong preclinical rationale for further clinical exploration of combining CCR2 antagonism with PD-1/PD-L1-directed immunotherapies across multiple tumor types especially given the availability of small molecule CCR2 inhibitors and antibodies.

A Whole-genome CRISPR Screen Identifies a Role of MSH2 in Cisplatin-mediated Cell Death in Muscle-invasive Bladder Cancer.

BACKGROUND: The response to first-line, platinum-based treatment of muscle-invasive bladder cancer has not improved in 3 decades. OBJECTIVE: To identify genes that influence cisplatin resistance in bladder cancer. DESIGN, SETTING, AND PARTICIPANTS: We performed a whole-genome CRISPR screen in a bladder cancer cell line to identify genes that mediate resistance to cisplatin. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Targeted validation was performed in two bladder cancer cell lines. The top gene candidate was validated in a publicly available bladder cancer dataset. RESULTS AND LIMITATIONS: From the CRISPR screen, we identified MSH2 as the most significantly enriched gene and mismatch repair as the most significantly enriched pathway that promoted resistance to cisplatin. Bladder cancer cells with knockdown of MSH2 showed a reduction in cisplatin-mediated apoptosis. MSH2 loss did not impact the sensitivity to other chemotherapies, including the cisplatin analog oxaliplatin. Bladder tumors with low MSH2 protein levels, quantified using reverse-phase protein array, showed poorer survival when treated with cisplatin- or carboplatin-based therapy; these results require future validation using immunohistochemistry. Additionally, results are retrospective from patients with primarily high-grade tumors; thus, validation in a controlled clinical trial is needed. CONCLUSIONS: We generated in vitro evidence that bladder cancer cell lines depleted of MSH2 are more resistant to cisplatin. We additionally found an association between low MSH2 in bladder tumors and poorer patient survival when treated with platinum-based chemotherapy. If successfully validated prospectively, MSH2 protein level could assist in the selection of patients for chemotherapy. PATIENT SUMMARY: We report the first evidence that MSH2 protein level may contribute to chemotherapy resistance observed in muscle-invasive bladder cancer. MSH2 has potential as a biomarker predictive of response to platinum-based therapy.

A Gene Expression Signature Predicts Bladder Cancer Cell Line Sensitivity to EGFR Inhibition.

BACKGROUND: Bladder cancer remains a cancer type in need of novel and alternative therapies. While multiple inhibitors of EGFR have been evaluated for efficacy in bladder cancer, the results have largely been disappointing with few patients responding to these therapies. Yet, there is a subset of patients that positively responds to EGFR inhibition with tumor shrinkage, indicating it is an effective treatment for a targeted set of bladder tumors. OBJECTIVE: To derive a gene expression signature capable of predicting the response to EGFR inhibition in bladder cancer cell lines. METHODS: he response to cetuximab for 68 colorectal cancer patients was used as training data to generate a gene expression signature. We applied this signature to bladder cancer cell lines and predictions were compared to the responses to seven EGFR inhibitors. RESULTS: A novel 67-gene signature derived from colorectal cancer was able to significantly identify bladder cancer cell lines by their response to several EGFR inhibitors. CONCLUSIONS: The 67-gene signature can determine bladder cancer cell line sensitivity to EGFR inhibition. This work demonstrates a preclinical strategy to identify bladder cancer cell lines for EGFR-targeted therapy.

Role of the androgen receptor in breast cancer and preclinical analysis of enzalutamide.

INTRODUCTION: The androgen receptor (AR) is widely expressed in breast cancers and has been proposed as a therapeutic target in estrogen receptor alpha (ER) negative breast cancers that retain AR. However, controversy exists regarding the role of AR, particularly in ER + tumors. Enzalutamide, an AR inhibitor that impairs nuclear localization of AR, was used to elucidate the role of AR in preclinical models of ER positive and negative breast cancer. METHODS: We examined nuclear AR to ER protein ratios in primary breast cancers in relation to response to endocrine therapy. The effects of AR inhibition with enzalutamide were examined in vitro and in preclinical models of ER positive and negative breast cancer that express AR. RESULTS: In a cohort of 192 women with ER + breast cancers, a high ratio of AR:ER (≥2.0) indicated an over four fold increased risk for failure while on tamoxifen (HR = 4.43). The AR:ER ratio had an independent effect on risk for failure above ER % staining alone. AR:ER ratio is also an independent predictor of disease-free survival (HR = 4.04, 95% CI: 1.68, 9.69; p = 0.002) and disease specific survival (HR = 2.75, 95% CI: 1.11, 6.86; p = 0.03). Both enzalutamide and bicalutamide inhibited 5-alpha-dihydrotestosterone (DHT)-mediated proliferation of breast cancer lines in vitro; however, enzalutamide uniquely inhibited estradiol (E2)-mediated proliferation of ER+/AR + breast cancer cells. In MCF7 xenografts (ER+/AR+) enzalutamide inhibited E2-driven tumor growth as effectively as tamoxifen by decreasing proliferation. Enzalutamide also inhibited DHT- driven tumor growth in both ER positive (MCF7) and negative (MDA-MB-453) xenografts, but did so by increasing apoptosis. CONCLUSIONS: AR to ER ratio may influence breast cancer response to traditional endocrine therapy. Enzalutamide elicits different effects on E2-mediated breast cancer cell proliferation than bicalutamide. This preclinical study supports the initiation of clinical studies evaluating enzalutamide for treatment of AR+ tumors regardless of ER status, since it blocks both androgen- and estrogen- mediated tumor growth.

French version of the Rating Scale for aggressive behaviour in the Elderly (F-RAGE): psychometric properties and diagnostic accuracy / Versão francesa da Escala de Avaliação do Comportamento Agressivo em Idosos: propriedades psicométricas e utilidade diagnóstica

Aggressive behaviour is the most disturbing and distressing behaviour displayed by elderly people. The prevalence of aggressive behaviour is around 50% among psychogeriatric patients. OBJECTIVE: This study sought to analyze the psychometric properties and diagnostic accuracy of the French version of the Rating Scale for Aggressive Behaviour in the Elderly (F-RAGE). METHODS: The F-RAGE was administered to 79 patients hospitalized in a geriatric psychiatry department. A psychiatrist, who was blind to the subjects' RAGE scores, performed the diagnosis for aggressivity based on global clinical impression. The F-RAGE and MMSE were applied by a trained researcher blind to subjects' clinical diagnoses while the Cohen-Mans Agitation Inventory and Neuropsychiatric Inventory were administered by medical and nursing staff. Internal consistency, reliability, cut-off points, sensitivity and specificity for F-RAGE were estimated. RESULTS: F-RAGE showed satisfactory validity and reliability measurements. Regarding reliability, Cronbach's ? coefficient was satisfactory with a value of 0.758. For diagnostic accuracy, a cut-off point of 8 points (sensitivity=74.19%; specificity=97.98%) and area under curve of 0.960 were estimated to distinguish between aggressive patients and control subjects. DISCUSSION: F-RAGE showed acceptable psychometric properties, supported by evidence of validity and reliability for its use in the diagnosis of aggressive behaviour in elderly.

O comportamento agressivo é o comportamento mais perturbador e angustiante que possa ser apresentado pelos idosos. A prevalência de comportamento agressivo é cerca de 50% entre os pacientes psicogeriátricos. OBJETIVO: Analisar as propriedades psicométricas e acurácia diagnóstica da versão francesa da Escala de Avaliação do Comportamento Agressivo em Idosos (F-RAGE). MÉTODOS: A F-RAGE foi administrada a 79 pacientes internados no departamento de psiquiatria geriátrica. Um psiquiatra que era cego às pontuações F-RAGE dos sujeitos realizou o diagnóstico de DSM-IV com base na impressão clínica global. O F-RAGE e MMSE foram realizados por um pesquisador treinado cego ao diagnóstico clínico dos sujeitos e o Inventário de agitação de Cohen-Mans e o Inventário Neuropsiquiátrico pela equipe médica e de enfermagem. Consistência interna, pontos de corte, sensibilidade e especificidade para F-RAGE foram estimados. RESULTADOS: F-RAGE mostrou validade satisfatória e medidas de confiabilidade. Em relação à confiabilidade, coeficiente ? de Cronbach foi satisfatória com um valor de 0,758. Para maior precisão de diagnóstico, um ponto de corte de 8 pontos (sensibilidade=74,2%, especificidade=98,0%) e área sob a curva de 0,960 foram estimados para distinguir entre os pacientes agressivos e controles.DISCUSSÃO: F-RAGE mostrou propriedades psicométricas aceitáveis, apoiados por evidências de validade e confiabilidade para sua utilização no diagnóstico do comportamento agressivo em idosos.

French version of the Rating Scale for aggressive behaviour in the Elderly (F-RAGE): psychometric properties and diagnostic accuracy.

Aggressive behaviour is the most disturbing and distressing behaviour displayed by elderly people. The prevalence of aggressive behaviour is around 50% among psychogeriatric patients. OBJECTIVE: This study sought to analyze the psychometric properties and diagnostic accuracy of the French version of the Rating Scale for Aggressive Behaviour in the Elderly (F-RAGE). METHODS: The F-RAGE was administered to 79 patients hospitalized in a geriatric psychiatry department. A psychiatrist, who was blind to the subjects' RAGE scores, performed the diagnosis for aggressivity based on global clinical impression. The F-RAGE and MMSE were applied by a trained researcher blind to subjects' clinical diagnoses while the Cohen-Mansfield Agitation Inventory and Neuropsychiatric Inventory were administered by medical and nursing staff. Internal consistency, reliability, cut-off points, sensitivity and specificity for F-RAGE were estimated. RESULTS: F-RAGE showed satisfactory validity and reliability measurements. Regarding reliability, Cronbach's α coefficient was satisfactory with a value of 0.758. For diagnostic accuracy, a cut-off point of 8 points (sensitivity=74.19%; specificity=97.98%) and area under curve of 0.960 were estimated to distinguish between aggressive patients and control subjects. DISCUSSION: F-RAGE showed acceptable psychometric properties, supported by evidence of validity and reliability for its use in the diagnosis of aggressive behaviour in elderly.

O comportamento agressivo é o comportamento mais perturbador e angustiante que possa ser apresentado pelos idosos. A prevalência de comportamento agressivo é cerca de 50% entre os pacientes psicogeriátricos. OBJETIVO: Analisar as propriedades psicométricas e acurácia diagnóstica da versão francesa da Escala de Avaliação do Comportamento Agressivo em Idosos (F-RAGE). MÉTODOS: A F-RAGE foi administrada a 79 pacientes internados no departamento de psiquiatria geriátrica. Um psiquiatra que era cego às pontuações F-RAGE dos sujeitos realizou o diagnóstico de DSM-IV com base na impressão clínica global. O F-RAGE e MMSE foram realizados por um pesquisador treinado cego ao diagnóstico clínico dos sujeitos e o Inventário de agitação de Cohen-Mansfield e o Inventário Neuropsiquiátrico pela equipe médica e de enfermagem. Consistência interna, pontos de corte, sensibilidade e especificidade para F-RAGE foram estimados. RESULTADOS: F-RAGE mostrou validade satisfatória e medidas de confiabilidade. Em relação à confiabilidade, coeficiente α de Cronbach foi satisfatória com um valor de 0,758. Para maior precisão de diagnóstico, um ponto de corte de 8 pontos (sensibilidade=74,2%, especificidade=98,0%) e área sob a curva de 0,960 foram estimados para distinguir entre os pacientes agressivos e controles. DISCUSSÃO: F-RAGE mostrou propriedades psicométricas aceitáveis, apoiados por evidências de validade e confiabilidade para sua utilização no diagnóstico do comportamento agressivo em idosos.

Restoration of miR-200c to ovarian cancer reduces tumor burden and increases sensitivity to paclitaxel.

A therapeutic intervention that could decrease tumor burden and increase sensitivity to chemotherapy would have a significant impact on the high morbidity rate associated with ovarian cancer. miRNAs have emerged as potential therapeutic candidates due to their ability to downregulate multiple targets involved in tumor progression and chemoresistance. miRNA-200c (miR-200c) is downregulated in ovarian cancer cell lines and stage III ovarian tumors, and low miR-200c correlates with poor prognosis. miR-200c increases sensitivity to taxanes in vitro by targeting class III ß-tubulin gene (TUBB3), a tubulin known to mediate chemoresistance. Indeed, we find that patients with tumors having low TUBB3 had significantly prolonged survival (average survival 52.73 ± 4.08 months) as compared with those having high TUBB3 (average survival 42.56 ± 3.19 months). miR-200c also targets TrkB, a mediator of resistance to anoikis. We show that restoration of miR-200c to ovarian cancer cells results in increased anoikis sensitivity and reduced adherence to biologic substrates in vitro. Because both chemo- and anoikis-resistance are critical steps in the progression of ovarian cancer, we sought to determine how restoration of miR-200c affects tumor burden and chemosensitivity in an in vivo preclinical model of ovarian cancer. Restoration of miR-200c in an intraperitoneal xenograft model of human ovarian cancer results in decreased tumor formation and tumor burden. Furthermore, even in established tumors, restoration of miR-200c, alone or in combination with paclitaxel, results in significantly decreased tumor burden. Our study suggests that restoration of miR-200c immediately before cytotoxic chemotherapy may allow for a better response or lower effective dose.

Development and validation of an instrument to detect depression in nursing homes. Nursing homes short depression inventory (NH-SDI).

UNLABELLED: Depression is often overlooked in elderly nursing home residents because symptoms may be masked or dismissed as an inevitable consequence of ageing. Current tools for the detection of depression in institutionalised older people are not always specific. AIMS: To construct and verify an instrument with which to detect depression in elderly nursing home residents (NH-SDI). METHOD: Firstly for the construction, 328 elderly people were selected at random from the residents of 17 nursing homes in France, and examined by a single investigator. The examination included a psychiatric assessment, an evaluation of cognitive function using the MMSE, an evaluation of depressive state using four different instruments (mini-GDS, Goldberg, DMAS, CSDD), and assessment of any changes in behaviour in those suffering from dementia, using the NPI. A second stage was to confirm NH-SDI in 99 institutionalised subjects. RESULTS: Following the selection of items, we created a scale of 16 dichotomous items (NH-SDI). The internal consistency was satisfactory (α Cronbach = 0.85), as was its reliability with a sensitivity of 85.1% and a specificity of 86.5% for a cut-off score above 5. CONCLUSIONS: The NH-SDI appears to be a useful instrument for the detection of depression in nursing homes and can easily be applied by healthcare staff as part of routine procedures.

Specific psychological and behavioral symptoms of depression in patients with dementia.

UNLABELLED: Behavioral and psychological symptoms in dementia (BPSD) are very common, with 90% of patients experiencing at least one during the course of the disease. One-third of persons with dementia have depressive symptoms, and concomitant BPSD are very likely. OBJECTIVE: This study aimed to characterize the psychological and behavioral manifestations of depression in patients with dementia. METHODS: We recruited patients with dementia from several nursing homes in the Limousin region of France. Depression was as diagnosed by the Cornell Scale for Depression in Dementia (CSDD) with a cut-off of 7, and BPSD were assessed using the Neuropsychiatric Inventory (NPI). RESULTS: Of 319 patients with dementia, 42.9% (n =137) were depressed and 75.9% (n = 242) had BPSD. All BPSD were significantly (p < 0.0001) more prevalent among depressed patients, but no significant differences were observed according to sex and age. The NPI showed that the most common additional symptoms in depressed patients were agitation (43.2%), anxiety (42.3%) and irritability (40.1%). Four NPI-based factors were indentified (63.9% of the common variance): factor 1 (disinhibition, irritability, agitation, anxiety), factor 2 (sleep disturbance, aberrant motor behavior, apathy), factor 3 (elation, hallucination, delirium) and the last with eating disorders. Depression in dementia patients was significantly associated with disinhibition, irritability, agitation, and anxiety. CONCLUSION: BPSD are common and a major problem. Before addressing them as isolated symptoms, it is important to consider comorbidity with depression in order to optimize the therapeutic approach.

A Pit-1 threonine 220 phosphomimic reduces binding to monomeric DNA sites to inhibit Ras and estrogen stimulation of the prolactin gene promoter.

Pit-1 is a POU-homeodomain transcription factor that dictates the ontogeny of pituitary somatotrophs, lactotrophs, and thyrotrophs through regulation of their respective protein hormone genes: GH, prolactin (PRL), and TSHbeta. Although Pit-1 threonine 220 (T220) and serine 115 are protein kinase phospho-acceptor sites, the transcriptional role of Pit-1 phosphorylation remains unclear. In the rat PRL promoter (rPRL), Ras-stimulated transcription is mediated by binding of Ets-1 and Pit-1 at a composite site (FPIV). Ets-1 and Pit-1 physically interact, and Pit-1 T220 is a major Ets-1 contact point. T220 was mutated to aspartic acid (D, to mimic phosphorylation) or a neutral alanine (A), and DNA binding and transcriptional activity were tested. The Pit-1 T220D mutation reduced binding at monomeric Pit-1 sites (FPIV, PRL-1d), but not dimeric Pit-1 sites (FPI). Pit-1 T220A bound all sites with wild-type (WT) affinity. In transfections of HeLa cells, each Pit-1 mutant transcriptionally activated the -425rPRL promoter and cooperated with Ets-1 to WT levels. In contrast, Pit-1-mediated Ras activation of the -425 rPRL promoter was significantly inhibited by T220D. Finally, Pit-1 synergistic activation of the 2500-bp rPRL promoter with estrogen receptor was reduced by T220D compared with T220A and WT Pit-1. Thus, phosphorylation of Pit-1 T220 reduces binding to monomeric sites blunting Ras and estrogen/estrogen receptor stimulation of the rPRL gene promoter. Consequently, T220 phosphorylation of Pit-1 by protein kinase A, protein kinase C, or cell cycle-dependent kinases appears to serve as a regulatory switch, inhibiting Ras and estrogen/estrogen receptor regulatory pathways, while enhancing the cAMP/protein kinase A response, thus allowing a more precise integration of pituitary responses to distinct signaling stimuli.

Use of the Visual Object and Space Perception (VOSP) test battery in two cases of posterior cortical atrophy.

Two patients presenting with predominantly dorsal posterior cortical atrophy were evaluated using the Visual Object and Space Perception (VOSP) test. The objective was to determine whether the VOSP was useful to discriminate damage to the ventral and the dorsal visual pathways. Both patients failed almost all the VOSP subtests, and the battery did not permit confirmation of the integrity of the ventral pathway. In addition, certain subtests evaluating dorsal function were nearly completed, probably due to a compensation strategy. Thus, evaluation using VOSP does not discriminate between predominantly ventral and predominantly dorsal clinical forms of posterior cortical atrophy.

ZEB1 expression in type I vs type II endometrial cancers: a marker of aggressive disease.

Zinc-finger E-box-binding homeobox 1 (ZEB1) is a transcription factor containing two clusters of Kruppel-type zinc-fingers, by which it binds E-box-like sequences on target DNAs. A role for ZEB1 in tumor progression, specifically, epithelial to mesenchymal transitions, has recently been revealed. ZEB1 acts as a master repressor of E-cadherin and other epithelial markers. We previously demonstrated that ZEB1 is confined to the stromal compartment in normal endometrium and low-grade endometrial cancers. Here, we quantify ZEB1 protein expression in endometrial samples from 88 patients and confirm that it is expressed at significantly higher levels in the tumor-associated stroma of low-grade endometrioid adenocarcinomas (type I endometrial cancers) compared to hyperplastic or normal endometrium. In addition, as we previously reported, ZEB1 is aberrantly expressed in the epithelial-derived tumor cells of highly aggressive endometrial cancers, such as FIGO grade 3 endometrioid adenocarcinomas, uterine serous carcinomas, and malignant mixed Müllerian tumors (classified as type II endometrial cancers). We now demonstrate, in both human endometrial cancer specimens and cell lines, that when ZEB1 is inappropriately expressed in epithelial-derived tumor cells, E-cadherin expression is repressed, and that this inverse relationship correlates with increased migratory and invasive potential. Forced expression of ZEB1 in the nonmigratory, low-grade, relatively differentiated Ishikawa cell line renders them migratory. Conversely, reduction of ZEB1 in a highly migratory and aggressive type II cell line, Hec50co, results in reduced migratory capacity. Thus, ZEB1 may be a biomarker of aggressive endometrial cancers at high risk of recurrence. It may help identify women who would most benefit from chemotherapy. Furthermore, if expression of ZEB1 in type II endometrial cancers could be reversed, it might be exploited as therapy for these highly aggressive tumors.

Differential utilization of transcription activation subdomains by distinct coactivators regulates Pit-1 basal and Ras responsiveness.

The POU-homeodomain transcription factor Pit-1 governs ontogeny and cell-specific gene expression of pituitary lactotropes, somatotropes, and thyrotropes. The splice isoform, Pit-1beta, inserts a 26-amino acid (AA) repressor at AA48 in the Pit-1 transcription activation domain (TAD). The Pit-1 TAD contains a basal regulatory subregion, R1 (AA1-45), and a basal and Ras-responsive region, R2 (AA46-80). To precisely map these activities, we generated GAL4-Pit-1/Pit-1betaTAD fusions and, in full-length HA-Pit-1, a series of substitution mutants of R2. Analysis in GH4 cells identified an activation domain at AA50-70, followed by an overlapping, dual-function, Ras-responsive-inhibitory domain, located from AA60-80. In contrast, GAL4-Pit-1betaTAD repressed both basal and Ras-mediated TAD activity. To determine the functional interplay between TAD subregions and the beta-domain, we inserted the beta-domain every 10 AA across the 80-AA Pit-1 TAD. Like wild-type Pit-1beta, each construct retained transcriptional activity in HeLa cells and repressed the Ras response in GH4 cells. However, beta-domain insertion at AA61 and 71 resulted in greater repression of Ras responsiveness, defining a critical R2 TAD spanning AA61-71 of Pit-1. Furthermore, Ras activation is augmented by steroid receptor coactivator 1, whereas cAMP response element binding protein-binding protein is not a Ras mediator in this system. In summary, the Pit-1/Pit-1beta TADs are composed of multiple, modular, and transferable subdomains, including a regulatory R1 domain, a basal activation region, a selective inhibitory-Ras-responsive segment, and a beta-specific repressor domain. These data provide novel insights into the mechanisms by which the Pit-1 TAD integrates DNA binding, protein partner interactions, and distinct signaling pathways to fine-tune Pit-1 activity.

Catalytic direct arylation with aryl chlorides, bromides, and iodides: intramolecular studies leading to new intermolecular reactions.

A catalyst for the intramolecular direct arylation of a broad range of simple and heterocyclic arenes with aryl iodides, bromides, and chlorides has been developed. These reactions occur in excellent yield and are highly selective. Studies with aryl iodides substrates revealed that catalyst poisoning occurs due to the accumulation of iodide in the reaction media. This can be overcome by the addition of silver salts which also permits these reactions to occur at lower temperature. The utility of the methodology is illustrated by a rapid synthesis of a carbazole natural product and by the synthesis of sterically encumbered tetra-ortho-substituted biaryls via ring-opening reactions of the direct arylation products. Mechanistic investigations have provided insight into the catalyst's mode of action and show the presence of a kinetically significant C-H bond cleavage in palladium-catalyzed direct arylation of simple arenes. Knowledge garnered from these studies has led to the development of new intermolecular arylation reactions with previously inaccessible arenes, opening the door for the development of other new direct arylation processes.

Ras signaling and transcriptional synergy at a flexible Ets-1/Pit-1 composite DNA element is defined by the assembly of selective activation domains.

Pit-1 and Ets-1 binding to a composite element synergistically activates and targets Ras-mitogen-activated protein kinase signaling to the rat prolactin promoter. These transcriptional responses appear to depend on three molecular features: organization of the Ets-1/Pit-1 composite element, physical interaction of these two factors via the Pit-1 homeodomain (amino acids 199-291) and the Ets-1 regulatory III domain (amino acids 190-257), and assembly of their transcriptional activation domains (TADs). Here we show that the organization of the Ets-1/Pit-1 composite element tolerates significant flexibility with regard to Ras stimulation and synergy. Specifically, the putative monomeric Pit-1 binding site can be substituted with bona fide binding sites for either a Pit-1 monomer or dimer, and these sites tolerated a separation of 28 bp. Additionally, we show that the physical interaction of Ets-1 and Pit-1 is not required for Ras responsiveness or synergy because block mutations of the Pit-1 interaction surface in Ets-1, which reduced Ets-1/Pit-1 binding in vitro, did not significantly affect Ets-1 stimulation of Ras responsiveness or synergy. We also show differential use of distinct TAD subtypes and Pit-1 TAD subregions to mediate either synergy or Ras responsiveness. Specifically, TADs from Gal4, VP16, or Ets-2 regulatory III domain linked to Ets-1 DNA binding domain constructs restored synergy to these TAD/Ets-1 DNA binding domain fusions. Conversely, deletion of the defined Pit-1 TAD (amino acids 2-80) retained synergy, but not Ras responsiveness. Consequently, we further defined the Pit-1 amino-terminal TAD into region 1 (R1, amino acids 2-45) and region 2 (R2, amino acids 46-80). R1 appears to regulate basal and synergistic responses, whereas the Ras response was mapped to R2. In summary, Ras responsiveness and Pit-1/Ets-1 synergy are mediated through the assembly of distinct TADs at a flexible composite element, indicating that different mechanisms underlie these two transcriptional responses and that the Pit-1 R2 subregion represents a novel, tissue-specific Ras-responsive TAD.