The complex understanding of Annexin A1 phosphorylation.

Abstract Annexin A1 (ANXA1) is the first characterized member of the annexins superfamily. It binds the cellular membrane phospholipids in Ca2 + regulated manner. Annexin A1 has been found in several tissues and many physiological roles as hormones secretion, vesiculation, inflammatory response, apoptosis and differentiation have been shown. Its subcellular localization and binding with many partner proteins are altered accordingly with its physiological role. The Annexin A1 membrane localization is crucial for binding to receptors, suggesting a paracrine and juxtacrine extracellular action. Annexin A1 is subjected to several post-translational modifications. In particular the protein is phosphorylated on several residues both on the N-terminal functional domain and on the C-terminus core. Different kinases have been identified as responsible for the phosphorylation status of selective residues. The specific change in the phosphorylation status on the different sites alters ANXA1 localization, binding properties and functions. This review shows the physiological relevance of the ANXA1 phosphorylation leading to the conclusion that numerous and different roles of Annexin A1 could be associated with different phosphorylations to alter not only intracellular localization and bindings to its partners but also the extracellular receptor interactions

NCI60 Cancer Cell Line Panel Data and RNAi Analysis Help Identify EAF2 as a Modulator of Simvastatin and Lovastatin Response in HCT-116 Cells

Simvastatin and lovastatin are statins traditionally used for lowering serum cholesterol levels. However, there exists evidence indicating their potential chemotherapeutic characteristics in cancer. In this study, we used bioinformatic analysis of publicly available data in order to systematically identify the genes involved in resistance to cytotoxic effects of these two drugs in the NCI60 cell line panel. We used the pharmacological data available for all the NCI60 cell lines to classify simvastatin or lovastatin resistant and sensitive cell lines, respectively. Next, we performed whole-genome single marker case-control association tests for the lovastatin and simvastatin resistant and sensitive cells using their publicly available Affymetrix 125K SNP genomic data. The results were then evaluated using RNAi methodology. After correction of the p-values for multiple testing using False Discovery Rate, our results identified three genes (NRP1, COL13A1, MRPS31) and six genes (EAF2, ANK2, AKAP7, STEAP2, LPIN2, PARVB) associated with resistance to simvastatin and lovastatin, respectively. Functional validation using RNAi confirmed that silencing of EAF2 expression modulated the response of HCT-116 colon cancer cells to both statins. In summary, we have successfully utilized the publicly available data on the NCI60 cell lines to perform whole-genome association studies for simvastatin and lovastatin. Our results indicated genes involved in the cellular response to these statins and siRNA studies confirmed the role of the EAF2 in response to these drugs in HCT-116 colon cancer cells

Statin use and risk of pancreatic cancer: Results from a large, clinic-based case-control study

BACKGROUND: Statins are cholesterol-lowering medications with pleiotropic effects including alterations in growth signaling as well as immunomodulatory and anti-inflammatory effects that may alter cancer risk. Evidence from previous epidemiologic studies is inconsistent regarding whether statin use is associated with reduced risk of pancreatic cancer (PC). METHODS: Patients with confirmed diagnoses of PC (cases) were recruited from medical and surgical oncology clinics, with controls (frequency-matched by sex and age) recruited from general medicine clinics, at a high-volume academic medical center over a six-year period (2006–2011). Direct interviews were conducted using an epidemiological risk factor questionnaire covering topics such as medical history, lifestyle factors, and medication usage. Adjusted multivariable logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (95%CI) as estimates of the relative risk of PC. RESULTS: Data were obtained from 536 cases and 869 controls. Ever use of statins was associated with 34% reduced PC risk (OR=0.66, 95%CI 0.47–0.92). In sex-stratified analyses, risk was statistically significantly reduced in men only (men: OR=0.50, 95%CI 0.32–0.79; women: OR=0.86, 95%CI 0.52–1.43). Duration of use was inversely associated with PC risk (>10 year use: OR=0.51 overall; in men, OR=0.41, 95%CI 0.21–0.80; p(trend)=0.006). CONCLUSIONS: This is the largest case-control study to demonstrate an inverse association between statin use and PC risk. Risk reduction in statin users appears to be sex-specific and is more pronounced in long-term users. Further research is warranted to better characterize this association and clarify roles of underlying biologic mechanisms

Preclinical evaluation of statins as a treatment for ovarian cancer

ObjectiveTo evaluate the potential for statins to treat ovarian cancer.MethodsThe sensitivity of 7 ovarian cancer cell lines to either statins or statins combined with either carboplatin or paclitaxel was assessed using monolayer cultures. Sensitivity to simvastatin was also evaluated in ovarian cancer spheroids. The kinetics of cell death induced by simvastatin was evaluated by measuring Trypan Blue exclusion. Autophagy induced by simvastatin was assessed by measuring LC3-II, p62 or Rab7 by immunoblotting or immunocytochemistry.ResultsAll statins except pravastatin demonstrated single agent activity against monolayers (IC50 = 1–35 μM) and spheroids (IC50 = 1–13 μM). This was mediated by HMG-CoAR inhibition, because either mevalonate or geranylgeraniol prevented the cytotoxic effects of simvastatin. Continuous exposure for 4 days was necessary to cause cell death. Simvastatin caused accumulation of p62 but loss of Rab7, suggesting inhibition of autophagosome trafficking. Accumulation of LC3-II was also observed, even in the presence of bafilomycin, suggesting additional stimulation of an earlier step in autophagy. Knockdown of the key autophagy regulator Atg5 caused a modest increase in the sensitivity of Ovcar-8 cells to simvastatin. Finally, additive or mild antagonist effects were observed when simvastatin was combined simultaneously with either carboplatin or paclitaxel, but when cells were exposed to simvastatin prior to carboplatin, profound antagonism was observed.ConclusionsThese observations suggest that clinical trials of statins in ovarian cancer should evaluate high doses and schedules that ensure continual inhibition of HMG-CoAR. Simvastatin has conflicting effects on the autophagy pathway and this may contribute to its cytotoxic activity