Jessica K. Paulus

Integrins and EGFR coordinately regulate the pro-apoptotic protein Bim to prevent anoikis

Epithelial cells must adhere to the extracellular matrix (ECM) for survival, as detachment from matrix triggers apoptosis or anoikis. Integrins are major mediators of adhesion between cells and ECM proteins, and transduce signals required for cell survival. Recent evidence suggests that integrin receptors are coupled to growth factor receptors in the regulation of multiple biological functions; however, mechanisms involved in coordinate regulation of cell survival are poorly understood and mediators responsible for anoikis have not been well characterized. Here, we identify the pro-apoptotic protein Bim as a critical mediator of anoikis in epithelial cells. Bim is strongly induced after cell detachment and downregulation of Bim expression by RNA interference (RNAi) inhibits anoikis. Detachment-induced expression of Bim requires a lack of β1-integrin engagement, downregulation of EGF receptor (EGFR) expression and inhibition of Erk signalling. Overexpressed EGFR was uncoupled from integrin regulation, resulting in the maintenance of Erk activation in suspension, and a block in Bim expression and anoikis. Thus, Bim functions as a key sensor of integrin and growth factor signals to the Erk pathway, and loss of such coordinate regulation may contribute to tumour progression.

Association of Episodic Physical and Sexual Activity With Triggering of Acute Cardiac Events: Systematic Review and Meta-analysis

CONTEXT Evidence has suggested that physical and sexual activity might be triggers of acute cardiac events. OBJECTIVE To assess the effect of episodic physical and sexual activity on acute cardiac events using data from case-crossover studies. DATA SOURCES MEDLINE and EMBASE (through February 2, 2011) and Web of Science (through October 6, 2010). STUDY SELECTION Case-crossover studies investigating the association between episodic physical or sexual activity and myocardial infarction (MI) or sudden cardiac death (SCD). DATA EXTRACTION Two reviewers extracted descriptive and quantitative information from each study. We calculated summary relative risks (RRs) using random-effects meta-analysis and absolute event rates based on US data for the incidence of MI and SCD. We used the Fisher P value synthesis method to test whether habitual physical activity levels modify the triggering effect and meta-regression to quantify the interaction between habitual levels of physical activity and the triggering effect. RESULTS We identified 10 studies investigating episodic physical activity, 3 studies investigating sexual activity, and 1 study investigating both exposures. The outcomes of interest were MI (10 studies), acute coronary syndrome (1 study), and SCD (3 studies). Episodic physical and sexual activity were associated with an increase in the risk of MI (RR = 3.45; 95% confidence interval [CI], 2.33-5.13, and RR = 2.70; 95% CI, 1.48-4.91, respectively). Episodic physical activity was associated with SCD (RR = 4.98; 95% CI, 1.47-16.91). The effect of triggers on the absolute rate of events was limited because exposure to physical and sexual activity is infrequent and their effect is transient; the absolute risk increase associated with 1 hour of additional physical or sexual activity per week was estimated as 2 to 3 per 10,000 person-years for MI and 1 per 10,000 person-years for SCD. Habitual activity levels significantly affected the association of episodic physical activity and MI (P < .001), episodic physical activity and SCD (P < .001), and sexual activity and MI (P = .04); in all cases, individuals with lower habitual activity levels had an increased RR for the triggering effect. For every additional time per week an individual was habitually exposed to physical activity, the RR for MI decreased by approximately 45%, and the RR for SCD decreased by 30%. CONCLUSION Acute cardiac events were significantly associated with episodic physical and sexual activity; this association was attenuated among persons with high levels of habitual physical activity.

Mocetinostat for relapsed classical Hodgkin's lymphoma: an open-label, single-arm, phase 2 trial

BACKGROUND The prognosis of patients with relapsed Hodgkins lymphoma, especially those who relapse after stem-cell transplantation, is poor, and the development of new agents for this patient population is an unmet medical need. We tested the safety and efficacy of mocetinostat, an oral isotype-selective histone deacetylase inhibitor, in patients with relapsed classical Hodgkins lymphoma. METHODS Patients with relapsed or refractory classical Hodgkins lymphoma aged 18 years or older were treated with mocetinostat administered orally three times per week, in 28-day cycles. Two doses were assessed (85 mg and 110 mg). Patients were treated until disease progression or prohibitive toxicity. The primary outcome was disease control rate, defined as complete response, partial response, or stable disease (for at least six cycles), analysed by intention to treat. This trial has been completed and is registered with ClinicalTrials.gov, number NCT00358982. FINDINGS 51 patients were enrolled. Initially, 23 patients were enrolled in the 110 mg cohort. Subsequently, because toxicity-related dose reductions were necessary in the 110 mg cohort, we treated 28 additional patients with a dose of 85 mg. On the basis of intent-to-treat analysis, the disease control rate was 35% (eight of 23 patients) in the 110 mg group and 25% (seven of 28) in the 85 mg group. 12 patients (24%) discontinued treatment because of adverse events, nine (32%) in the 85 mg cohort and three (13%) in the 110 mg cohort. The most frequent treatment-related grade 3 and 4 adverse events were neutropenia (four patients [17%] in the 110 mg group, three [11%] in the 85 mg group); fatigue (five patients [22%] in the 110 mg group, three [11%] in the 85 mg group); and pneumonia (four patients [17%] in the 110 mg group, two [7%] in the 85 mg group). Four patients, all in the 110 mg cohort, died during the study, of which two might have been related to treatment. INTERPRETATION Mocetinostat, 85 mg three times per week, has promising single-agent clinical activity with manageable toxicity in patients with relapsed classical Hodgkins lymphoma. FUNDING MethylGene Inc, Montreal, Canada; Celgene Corporation, Summit, NJ, USA; Tufts Medical Center, Boston, MA, USA.

G1/S Cell Cycle Arrest Provides Anoikis Resistance through Erk-Mediated Bim Suppression

ABSTRACT Proper attachment to the extracellular matrix is essential for cell survival. Detachment from the extracellular matrix results in an apoptotic process termed anoikis. Anoikis induction in MCF-10A mammary epithelial cells is due not only to loss of survival signals following integrin disengagement, but also to consequent downregulation of epidermal growth factor (EGFR) and loss of EGFR-induced survival signals. Here we demonstrate that G1/S arrest by overexpression of the cyclin-dependent kinase inhibitors p16INK4a, p21Cip1, or p27Kip1 or by treatment with mimosine or aphidicolin confers anoikis resistance in MCF-10A cells. G1/S arrest-mediated anoikis resistance involves suppression of the BH3-only protein Bim. Furthermore, in G1/S-arrested cells, Erk phosphorylation is maintained in suspension and is necessary for Bim suppression. Following G1/S arrest, known proteins upstream of Erk, including Raf and Mek, are not activated. However, retained Erk activation under conditions in which Raf and Mek activation is lost is observed, suggesting that G1/S arrest acts at the level of Erk dephosphorylation. Thus, anoikis resistance by G1/S arrest is mediated by a mechanism involving Bim suppression through maintenance of Erk activation. These results provide a novel link between cell cycle arrest and survival, and this mechanism could contribute to the survival of nonreplicating, dormant tumor cells that avert apoptosis during early stages of metastasis.

Alkaline Phosphatase Predicts Survival in Patients with Metastatic Neuroendocrine Tumors

The clinical course of patients with metastatic neuroendocrine tumors is highly variable. While some patients experience an indolent clinical course over many years, other patients may rapidly succumb to their disease. Little is known about prognostic factors in these patients, making decisions regarding their management more difficult.We performed a retrospective analysis of 137 patients with metastatic neuroendocrine tumors referred to our institution for treatment. Potential prognostic factors were evaluated using multivariate survival analysis. The median overall survival of patients in our cohort was 6.0 years, although the range of survival times was broad (48 days to 23.4 years). Alkaline phosphatase levels above normal were predictive of shorter survival in both univariate and multivariate analysis. Elevated chromogranin A levels were also associated with shorter survival in univariate analysis; in a multivariate analysis, however, this correlation was no longer significant. There was no association between survival and gender, primary tumor site, or presence or absence of carcinoid syndrome. Elevated alkaline phosphatase is a robust adverse prognostic factor for survival in patients with metastatic neuroendocrine tumors and may be superior to chromogranin A in this setting. Close monitoring of alkaline phosphatase levels may be useful when considering initiation or changes of therapy in patients with metastatic neuroendocrine tumors.

Prediction Model for 30-Day Hospital Readmissions Among Patients Discharged Receiving Outpatient Parenteral Antibiotic Therapy

BACKGROUND Factors associated with readmission for patients prescribed outpatient parenteral antibiotic therapy (OPAT) at hospital discharge have not been definitively identified. The study aim was to develop a model of 30-day readmissions for OPAT patients. METHODS A database comprising 782 OPAT patients treated between 2009 and 2011 at a single academic center was created. Variables collected included patient demographics, comorbidities, infections, and antibiotic classes. Final model discrimination was assessed using the c-statistic, and calibration was examined graphically. RESULTS Mean patient age was 58 years (range, 18-95 years), 43% were women, and the most common diagnoses were bacteremia (24%), osteomyelitis (20%), and pyelonephritis (13%). The unplanned 30-day readmission rate was 26%. The leading indications for readmission were non-infection related (30%), worsening infection (29%), and new infection (19%). The final regression model consisted of age (odds ratio [OR], 1.09 per decade; 95% confidence interval [CI], 0.99-1.21), aminoglycoside use (OR, 2.33; 95% CI, 1.17-4.57), resistant organisms (OR, 1.57; 95% CI, 1.03-2.36), and number of prior hospital discharges without intravenous antibiotics in the past 12 months (OR, 1.20 per prior admission; 95% CI, 1.09-1.32). The c-statistic was 0.61 and the highest-risk quintile of patients had almost a 3-fold higher rate of readmission compared to the lowest. CONCLUSIONS Patients prescribed OPAT are at risk for readmission. A subgroup of patients at especially high risk can be identified using easily obtainable clinical characteristics at the time of hospital discharge. More intensive interventions to prevent OPAT readmissions should be targeted and tested with those at highest risk.

Risk of Anal Cancer in a Cohort With Human Papillomavirus–related Gynecologic Neoplasm

OBJECTIVE: To assess the development of anal cancer in women diagnosed with a human papillomavirus–related cervical, vulvar, or vaginal neoplasm. METHODS: Using data from National Cancer Institutes Surveillance, Epidemiology and End Results program from 1973 through 2007, 189,206 cases with either in situ or invasive cervical, vulvar, or vaginal neoplasm were followed for 138,553,519 person-years for the development of subsequent primary anal cancer. Standardized incidence ratios were calculated from the observed number of subsequent anal cancers compared with those expected based on age-, race-, and calendar year–specific rates in the nonaffected population. RESULTS: Anal cancer developed in 255 women with a history of in situ or invasive gynecologic neoplasm, aggregate standardized incidence ratio of 13.6 (95% confidence interval [CI] 11.9–15.3), indicating a 13-fold increase in anal cancer compared with expected. The standardized incidence ratio for anal cancer incidence among women with in situ vulvar cancer was 22.2 (95% CI 16.7–28.4) and was 17.4 (95% CI 11.5–24.4) for those with invasive vulvar cancer. The standardized incidence ratio for anal cancer incidence in women with in situ cervical cancer was 16.4 (95% CI 13.7–19.2) and was 6.2 (95% CI 4.1–8.7) for women with invasive cervical cancer. The standardized incidence ratio for anal cancer incidence among women with in situ vaginal cancer was 7.6 (95% CI 2.4–15.6) and was 1.8 (95% CI 0.2–5.3) for invasive vaginal cancer. CONCLUSION: Women with human papillomavirus–related gynecologic neoplasm are at higher risk for developing anal cancer compared with the general population. This high-risk population may benefit from close observation and screening for anal cancer. LEVEL OF EVIDENCE: II

Can We Trust Observational Studies Using Propensity Scores in the Critical Care Literature? A Systematic Comparison With Randomized Clinical Trials.

Objective:To assess the degree of agreement between propensity score studies and randomized clinical trials in critical care research. Data Sources:Propensity score studies published in highly cited critical care or general medicine journals or included in a previous systematic review; corresponding randomized clinical trials included in Cochrane Systematic Reviews or published in PubMed. Study Selection:We identified propensity score studies of the effects of therapeutic interventions on short- or long-term mortality. We systematically matched propensity score studies to randomized clinical trials based on patient selection criteria, interventions, and outcomes. Data Extraction:We appraised the methods of included studies and extracted treatment effect estimates to compare the results of propensity score studies and randomized clinical trials. When multiple studies were identified for the same topic, we performed meta-analyses to obtain summary treatment effect estimates. Data Synthesis:We matched 21 propensity score studies with 58 randomized clinical trials in 18 distinct comparisons (median, one propensity score study and two randomized clinical trials per comparison), for short- and long-term mortality. We found one statistically significant difference between designs (hyperoncotic albumin vs crystalloid fluids) among these 18 comparisons. Propensity score studies did not produce systematically higher (or lower) treatment effect estimates compared with randomized clinical trials, but estimates from the two designs differed by more than 30% in one third of the comparisons examined. Observational studies in critical care met widely accepted methodological standards for propensity score analyses. Conclusions:Across diverse critical care topics, propensity score studies published in high-impact journals produced results that were generally consistent with the findings of randomized clinical trials. However, caution is needed when interpreting propensity score studies because occasionally their results contradict those of randomized clinical trials and there is no reliable way to predict disagreements.

Out-of-Hospital Use of Proton Pump Inhibitors and Hypomagnesemia at Hospital Admission: A Nested Case-Control Study

BACKGROUND Case series suggest that long-term use of proton pump inhibitors (PPIs) is associated with hypomagnesemia, but the current literature lacks systematically collected data. Our aim was to examine whether hypomagnesemia at the time of hospital admission is associated with out-of-hospital use of PPIs. STUDY DESIGN Nested case-control study matched for age and sex. SETTING & PARTICIPANTS Data were collected retrospectively from a tertiary acute-care facility. Eligible cases consisted of 402 adults with hypomagnesemia (serum magnesium <1.4 mEq/L) at the time of hospital admission to medical services, age- and sex-matched with 402 control individuals with normal serum magnesium levels (1.4-2.0 mEq/L). PREDICTOR Out-of-hospital PPI use was identified in the hospital record. An omeprazole equivalent dose was calculated when possible. Covariates included the Charlson-Deyo comorbidity index, diabetes, diuretic use, estimated glomerular filtration rate, and gastroesophageal reflux. OUTCOME Multivariable conditional logistic regression analyses were used to examine the association of PPI use with hypomagnesemia at the time of hospital admission. RESULTS PPI use was not associated with hypomagnesemia (adjusted OR, 0.82; 95% CI, 0.61-1.11). Neither PPI type nor omeprazole equivalent daily dose was associated with hypomagnesemia. Sensitivity analyses of PPI use restricted to patients with esophageal disorders (adjusted OR, 1.00; 95% CI, 0.69-1.45), severe hypomagnesemia (magnesium, ≤1.0 mEq/L; adjusted OR, 0.78; 95% CI, 0.13-4.61), or estimated glomerular filtration rate ≥60 mL/min/1.73 m(2) (adjusted OR, 0.84; 95% CI, 0.53-1.34) were unrevealing. LIMITATIONS Exposure misclassification; hospitalized patients on medical services may not be representative of a broader ambulatory-based population. CONCLUSIONS In a hospital-based adult population, out-of-hospital PPI use is not associated with hypomagnesemia at the time of hospital admission to medical services. In light of these inconclusive results, prospective cohort studies are needed to address this rare potential medication-related adverse effect.

Diabetes, Metformin Use, and Colorectal Cancer Survival in Postmenopausal Women

BACKGROUND Observational studies have associated metformin use with lower colorectal cancer (CRC) incidence but few studies have examined metformins influence on CRC survival. We examined the relationships among metformin use, diabetes, and survival in postmenopausal women with CRC in the Womens Health Initiative (WHI) clinical trials and observational study. METHODS 2066 postmenopausal women with CRC were followed for a median of 4.1 years, with 589 deaths after CRC diagnosis from all causes and 414 deaths directly attributed to CRC. CRC-specific survival was compared among women with diabetes with metformin use (n=84); women with diabetes with no metformin use (n=128); and women without diabetes (n=1854). Cox proportional hazard models were used to estimate associations among metformin use, diabetes and survival after CRC. Strategies to adjust for potential confounders included: multivariate adjustment with known predictors of colorectal cancer survival and construction of a propensity score for the likelihood of receiving metformin, with model stratification by propensity score quintile. RESULTS After adjusting for age and stage, CRC specific survival in women with diabetes with metformin use was not significantly different compared to that in women with diabetes with no metformin use (HR 0.75; 95% CI 0.40-1.38, p=0.67) and to women without diabetes (HR 1.00; 95% CI 0.61-1.66, p=0.99). Following propensity score adjustment, the HR for CRC-specific survival in women with diabetes with metformin use compared to non-users was 0.78 (95% CI 0.38-1.55, p=0.47) and for overall survival was 0.86 (95% CI 0.49-1.52; p=0.60). CONCLUSIONS In postmenopausal women with CRC and DM, no statistically significant difference was seen in CRC specific survival in those who used metformin compared to non-users. Analyses in larger populations of colorectal cancer patients are warranted.