Acetyl-CoA synthetases ACSS1 and ACSS2 are 4-hydroxytamoxifen responsive factors that promote survival in tamoxifen treated and estrogen deprived cells.

Acetyl-CoA synthetases ACSS1 and ACSS2 promote conversion of acetate to acetyl-CoA for use in lipid synthesis, protein acetylation, and energy production. These enzymes are elevated in some cancers and important for cell survival under hypoxia and nutrient stress. 4-hydroxytamoxifen (4-OHT) can induce metabolic changes that increase cancer cell survival. An effect of 4-OHT on expression of ACSS1 or ACSS2 has not been reported. We found ACSS1 and ACSS2 are increased by 4-OHT in estrogen receptor-α positive (ER+) breast cancer cells and 4-OHT resistant derivative cells. ERα knockdown blocked ACSS1 induction by 4-OHT but not ACSS2. 4-OHT also induced ACSS2 but not ACSS1 expression in triple negative breast cancer cells. Long-term estrogen deprivation (LTED) is a model for acquired resistance to aromatase inhibitors. We found LTED cells and tumors express elevated levels of ACSS1 and/or ACSS2 and are especially sensitive to viability loss caused by depletion of ACSS1 and ACSS2 or treatment with an ACSS2-specific inhibitor. ACSS2 inhibitor also increased toxicity in cells treated with 4-OHT. We conclude ACSS1 and ACSS2 are 4-OHT regulated factors important for breast cancer cell survival in 4-OHT-treated and long-term estrogen deprived cells.

Inhibitors of Jumonji C domain-containing histone lysine demethylases overcome cisplatin and paclitaxel resistance in non-small cell lung cancer through APC/Cdh1-dependent degradation of CtIP and PAF15.

The Jumonji C domain-containing family of histone lysine demethylases (Jumonji KDMs) have emerged as promising cancer therapy targets. These enzymes remove methyl groups from various histone lysines and, in turn, regulate processes including chromatin compaction, gene transcription, and DNA repair. Small molecule inhibitors of Jumonji KDMs have shown promise in preclinical studies against non-small cell lung cancer (NSCLC) and other cancers. However, how these inhibitors influence cancer therapy responses and/or DNA repair is incompletely understood. In this study, we established cell line and PDX tumor model systems of cisplatin and paclitaxel-resistant NSCLC. We showed that resistant cells and tumors express high levels of Jumonji-KDMs. Knockdown of individual KDMs or treatment with a pan-Jumonji KDM inhibitor sensitized the cells and tumors to cisplatin and paclitaxel and blocked NSCLC in vivo tumor growth. Mechanistically, we found inhibition of Jumonji-KDMs triggers APC/Cdh1-dependent degradation of CtIP and PAF15, two DNA repair proteins that promote repair of cisplatin and paclitaxel-induced DNA lesions. Knockdown of CtIP and PAF15 sensitized resistant cells to cisplatin, indicating their degradation when Jumonji KDMs are inhibited contributes to cisplatin sensitivity. Our results support the idea that Jumonji-KDMs are a targetable barrier to effective therapy responses in NSCLC. Inhibition of Jumonji KDMs increases therapy (cisplatin/paclitaxel) sensitivity in NSCLC cells, at least in part, by promoting APC/Cdh1-dependent degradation of CtIP and PAF15.

RBL2/DREAM-mediated repression of the Aurora kinase A/B pathway determines therapy responsiveness and outcome in p53 WT NSCLC.

Wild-type p53 is a stress-responsive transcription factor and potent tumor suppressor. P53 activates or represses genes involved in cell cycle progression or apoptosis in order to arrest the cell cycle or induce cell death. Transcription repression by p53 is indirect and requires repressive members of the RB-family (RB1, RBL1, RBL2) and formation of repressor complexes of RB1-E2F and RBL1/RBL2-DREAM. Many aurora kinase A/B (AURKA/B) pathway genes are repressed in a p53-DREAM-dependent manner. We found heightened expression of RBL2 and reduced expression of AURKA/B pathway genes is associated with improved outcomes in p53 wild-type but not p53 mutant non-small cell lung cancer (NSCLC) patients. Knockdown of p53, RBL2, or the DREAM component LIN37 increased AURKA/B pathway gene expression and reduced paclitaxel and radiation toxicity in NSCLC cells. In contrast, pharmacologic inhibition of AURKA/B or knockdown of AURKA/B pathway components increased paclitaxel and IR sensitivity. The results support a model in which p53-RBL2-DREAM-mediated repression of the AURKA/B pathway contributes to tumor suppression, improved tumor therapy responses, and better outcomes in p53 wild-type NSCLCs.

Prolyl Carboxypeptidase Maintains Receptor Tyrosine Kinase Signaling and Is a Potential Therapeutic Target in Triple Negative Breast Cancer.

TNBC is an aggressive cancer sub-type with limited treatment options and poor prognosis. New therapeutic targets are needed to improve outcomes in TNBC patients. PRCP is a lysosomal serine protease that cleaves peptide substrates when the penultimate amino acid is proline. A role for PRCP in TNBC or other cancers, and its potential as a therapy target has not yet been tested. In the current study, we found high tumor expression of PRCP associates with worse outcome and earlier recurrence in TNBC patients. Knockdown of PRCP or treatment with a small molecule PRCP inhibitor blocked proliferation and survival in TNBC cell lines and inhibited growth of TNBC tumors in mice. Mechanistically, we found PRCP maintains signaling from multiple receptor tyrosine kinases (RTKs), potentially by promoting crosstalk between RTKs and G-protein coupled receptors (GPCRs). Lastly, we found that the PRCP inhibitor caused synergistic killing of TNBC cells when combined with the EGFR and ErbB2 inhibitor lapatinib. Our results suggest that PRCP is potential prognostic marker for TNBC patient outcome and a novel therapeutic target for TNBC treatment.

Prolylcarboxypeptidase promotes IGF1R/HER3 signaling and is a potential target to improve endocrine therapy response in estrogen receptor positive breast cancer.

Prolylcarboxypeptidase (PRCP) is a lysosomal serine protease that cleaves peptide substrates when the penultimate amino acid is proline. Previous studies have linked PRCP to blood-pressure and appetite control through its ability to cleave peptide substrates such as angiotensin II and α-MSH. A potential role for PRCP in cancer has to date not been widely appreciated. Endocrine therapy resistance in breast cancer is an enduring clinical problem mediated in part by aberrant receptor tyrosine kinase (RTK) signaling. We previously found PRCP overexpression promoted 4-hydroxytamoxifen (4-OHT) resistance in estrogen receptor-positive (ER+) breast cancer cells. Currently, we tested the potential association between PRCP with breast cancer patient outcome and RTK signaling, and tumor responsiveness to endocrine therapy. We found high PRCP protein levels in ER+ breast tumors associates with worse outcome and earlier recurrence in breast cancer patients, including patients treated with TAM. We found a PRCP specific inhibitor (PRCPi) enhanced the response of ER+ PDX tumors and MCF7 tumors to endoxifen, an active metabolite of TAM in mice. We found PRCP increased IGF1R/HER3 signaling and AKT activation in ER+ breast cancer cells that was blocked by PRCPi. Thus, PRCP is an adverse prognostic marker in breast cancer and a potential target to improve endocrine therapy in ER+ breast cancers.

Fatty acid oxidation and autophagy promote endoxifen resistance and counter the effect of AKT inhibition in ER-positive breast cancer cells.

Tamoxifen (TAM) is the first-line endocrine therapy for estrogen receptor-positive (ER+) breast cancer (BC). However, acquired resistance occurs in ∼50% cases. Meanwhile, although the PI3K/AKT/mTOR pathway is a viable target for treatment of endocrine therapy-refractory patients, complex signaling feedback loops exist, which can counter the effectiveness of inhibitors of this pathway. Here, we analyzed signaling pathways and metabolism in ER+ MCF7 BC cell line and their TAM-resistant derivatives that are co-resistant to endoxifen using immunoblotting, quantitative polymerase chain reaction, and the Agilent Seahorse XF Analyzer. We found that activation of AKT and the energy-sensing kinase AMPK was increased in TAM and endoxifen-resistant cells. Furthermore, ERRα/PGC-1ß and their target genes MCAD and CPT-1 were increased and regulated by AMPK, which coincided with increased fatty acid oxidation (FAO) and autophagy in TAM-resistant cells. Inhibition of AKT feedback-activates AMPK and ERRα/PGC-1ß-MCAD/CPT-1 with a consequent increase in FAO and autophagy that counters the therapeutic effect of endoxifen and AKT inhibitors. Therefore, our results indicate increased activation of AKT and AMPK with metabolic reprogramming and increased autophagy in TAM-resistant cells. Simultaneous inhibition of AKT and FAO/autophagy is necessary to fully sensitize resistant cells to endoxifen.

Prolyl endopeptidase inhibitor Y-29794 blocks the IRS1-AKT-mTORC1 pathway and inhibits survival and in vivo tumor growth of triple-negative breast cancer.

Prolyl endopeptidase (PREP), also known as prolyl oligopeptidase (POP), is an enzyme that cleaves short peptides (<30 amino acids in length) on the C-terminal side of proline. PREP is highly expressed in multiple carcinomas and is a potential target for cancer therapy. A potent inhibitor of PREP, Y-29794, causes long-lasting inhibition of PREP in mouse tissues. However, there are no reports on Y-29794 effects on cancer cell and tumor proliferation. Using cell line models of aggressive triple-negative breast cancer (TNBC), we show here that Y-29794 inhibited proliferation and induced death in multiple TNBC cell lines. Cell death induced by Y-29794 coincided with inhibition of the IRS1-AKT-mTORC1 survival signaling pathway, although stable depletion of PREP alone was not sufficient to reduce IRS1-AKT-mTORC1 signaling or induce death. These results suggest that Y-29794 elicits its cancer cell killing effect by targeting other mechanisms in addition to PREP. Importantly, Y-29794 inhibited tumor growth when tested in xenograft models of TNBC in mice. Induction of cell death in culture and inhibition of xenograft tumor growth support the potential utility of Y-29794 or its derivatives as a treatment option for TNBC tumors.

Check it, change it: a community-based, multifaceted intervention to improve blood pressure control.

BACKGROUND: Although home blood pressure (BP) monitoring interventions have shown potential in selected populations, it is unclear whether such strategies can be generalized. We sought to determine whether a multifaceted BP control program that uses a web-based health portal (Heart360), community health coaches, and physician assistant guidance could improve hypertension control in a diverse community setting. METHODS AND RESULTS: Between September 12, 2010, and November 11, 2011 Check It, Change It, a community-based hypertension quality improvement program, enrolled 1756 patients with hypertension from 8 clinics in Durham County, NC. The Check It, Change It community intervention was evaluated using a prepost study design without a concurrent control. Participants were stratified into 3 tiers according to their initial BP: tier 0 (BP <140/90 mm Hg)=51% of population, tier 1 (BP=140/90-159/99 mm Hg)=30% of total, and tier 2 (BP ≥159/99 mm Hg)=19% of total. Overall, median age was 59 years (interquartile range, 49-69), 67% were female, and 76% black. After 6 months, the mean overall systolic BP declined 4.7 mm Hg. Rates of achieving target BP control (<140/90) increased overall from 51% at baseline to 63% by 6 months, and 69% had either reached their BP target or had reduced their baseline systolic BP by 10 mm Hg or more. CONCLUSIONS: A multicomponent-tiered hypertension program was associated with improved BP control in a diverse community-based population.

Check it, change it: a community-based intervention to improve blood pressure control.

BACKGROUND: Despite the widespread availability of effective and affordable therapies, hypertension remains this country's most significant modifiable cardiovascular risk factor. Approximately 30% to 50% of individuals with hypertension currently fail to reach guideline-recommended target blood pressure (BP) goals. Although multiple interventions have been proposed to affect better hypertension control, the integration of multiple elements in a community-based program has not been evaluated to date. METHODS AND RESULTS: We created a broadly inclusive community-based initiative to control hypertension called Check It, Change It: The Durham Blood Pressure Challenge (CICI). We enrolled ≈2000 participants with hypertension in 8 ambulatory clinics across Durham County, NC. The CICI program engaged individuals by providing them with tools for self-monitoring and tied this information to their caregivers via a web-based portal (the American Heart Association's Heart360, a remote BP monitoring system). Additionally, the CICI facilitated clinical intervention of high-risk individuals using physician assistants and community health coaches. The primary outcome will be a change in BP during the 6 months postenrollment in the program, which will be compared with concurrent and historical control populations of nonparticipants. CONCLUSIONS: We think that this integrated and tiered approach will lead to improved BP control within 6 months. If successful, the CICI program has the potential to enhance community-level BP control.

Temporal trends and geographic variation of lower-extremity amputation in patients with peripheral artery disease: results from U.S. Medicare 2000-2008.

OBJECTIVES: This study sought to characterize temporal trends, patient-specific factors, and geographic variation associated with amputation in patients with lower-extremity peripheral artery disease (LE PAD) during the study period. BACKGROUND: Amputation represents the end-stage failure for those with LE PAD, and little is known about the rates and geographic variation in the use of LE amputation. METHODS: By using data from the Centers for Medicare & Medicaid Services (CMS) from January 1, 2000, to December 31, 2008, we examined national patterns of LE amputation among patients age 65 years or more with PAD. Multivariable logistic regression was used to adjust regional results for other patient demographic and clinical factors. RESULTS: Among 2,730,742 older patients with identified PAD, the overall rate of LE amputation decreased from 7,258 per 100,000 patients with PAD to 5,790 per 100,000 (p < 0.001 for trend). Male sex, black race, diabetes mellitus, and renal disease were all independent predictors of LE amputation. The adjusted odds ratio of LE amputation per year between 2000 and 2008 was 0.95 (95% CI: 0.95-0.95, p < 0.001). CONCLUSIONS: From 2000 to 2008, LE amputation rates decreased significantly among patients with PAD. However, there remains significant patient and geographic variation in amputation rates across the United States.

Randomized trial of targeted performance feedback to facilitate quality improvement in acute myocardial infarction care.

BACKGROUND: Efforts to improve quality of care for patients with acute myocardial infarction (AMI) are a national priority. To date, there have been few studies that have prospectively evaluated hospital quality improvement (QI) interventions. METHODS AND RESULTS: Using hospitals in the National Cardiovascular Data Registry (NCDR) ACTION Registry-GWTG, a cluster randomized trial of the effectiveness of targeted performance feedback to facilitate process improvement for AMI care will be conducted. ACTION Registry-GWTG hospitals with a minimum of 50 AMI patients per 2 quarters are eligible for randomization. The control arm receives standard performance feedback reports, and the intervention arm receives standard performance feedback reports in addition to a supplemental report on the "top 3" centrally identified, hospital-specific performance gaps. The primary outcome will be improvement in a composite of all metrics, and the secondary outcome will be improvement in the targeted metrics. At study inception in January 2009, 149 sites were randomized: 76 to the intervention arm, and 73 to the control arm. Intervention and control sites were well balanced in terms of baseline performance, center characteristics, and AMI volume (≈70 patients per quarter). The intervention phase will continue for 5 feedback cycles, each containing 2 quarters of data feedback over 18 months. A final trial outcome report will follow. CONCLUSIONS: This randomized trial will evaluate a novel hospital-level QI intervention of targeted performance feedback for AMI, thereby demonstrating the effective use of national registries for QI and furthering our understanding of effective QI methods.