Lovastatin inhibits EGFR dimerization and AKT activation in squamous cell carcinoma cells: potential regulation by targeting rho proteins

Regulatory effects of statins on Akt signaling for prevention of cancers

Statins, which are primarily used as lipid-lowering drugs, have been found to exhibit anti-tumor effects through modulating and interfering with various signaling pathways. In observational studies, statin use has been associated with a significant reduction in the progression of various cancers, including colon, lung, prostate, pancreas, and esophagus cancer, as well as melanoma and B and T cell lymphoma. The mevalonate pathway, which is affected by statins, plays a crucial role in activating Rho, Ras, and Rab proteins, thereby impacting the proliferation and apoptosis of tumor cells. Statins block this pathway, leading to the inhibition of isoprenoid units, which are critical for the activation of these key proteins, thereby affecting cancer cell behavior. Additionally, statins affect MAPK and Cdk2, which in turn reduce the expression of p21 and p27 cyclin-dependent kinase inhibitors. Akt signaling plays a crucial role in key cancer cell features like proliferation, invasion, and apoptosis by activating multiple effectors in downstream pathways such as FOXO, PTEN, NF-κB, GSK3β, and mTOR. The PI3K/Akt signaling is necessary for many events in the metastatic pathway and has been implicated in the resistance to cytostatic drugs. The Akt/PTEN axis is currently attracting great interest for its role in carcinogenesis. Statins have been shown to activate the purinergic receptor P2X7 and affect Akt signaling, which may have important anti-cancer effects. Hence, targeting Akt shows promise as an effective approach to cancer prevention and therapy. This review aims to provide a comprehensive discussion on the specific impact of statins through Akt signaling in different types of cancer.

Association between Statins Types with Incidence of Liver Cancer: An Updated Meta-analysis

BACKGROUND

Previous studies have found a potential role for statins in liver cancer prevention.

OBJECTIVE

This study aimed to explore the effect of different types of statins on the incidence of liver cancer.

METHODS

Relevant articles were systematically retrieved from PubMed, EBSCO, Web of Science, and Cochrane Library databases from inception until July 2022 to explore the relationship between lipophilic statins or hydrophilic statins exposure and the incidence of liver cancer. The main outcome was the incidence of liver cancer.

RESULTS

Eleven articles were included in this meta-analysis. The pooled results showed a reduced incidence of liver cancer in patients exposed to lipophilic statins (OR=0.54, p < 0.001) and hydrophilic statins (OR=0.56, p < 0.001) compared with the non-exposed cohort. Subgroup analysis showed that both exposures to lipophilic (Eastern countries: OR=0.51, p < 0.001; Western countries: OR=0.59, p < 0.001) and hydrophilic (Eastern countries: OR=0.51, p < 0.001; Western countries: OR=0.66, p=0.019) statins reduced the incidence of liver cancer in Eastern and Western countries, and the reduction was most significant in Eastern countries. Moreover, atorvastatin (OR=0.55, p < 0.001), simvastatin (OR=0.59, p < 0.001), lovastatin (OR=0.51, p < 0.001), pitavastatin (OR=0.36, p=0.008) and rosuvastatin (OR=0.60, p=0.027) could effectively reduce the incidence of liver cancer, unlike fluvastatin, cerivastatin and pravastatin.

CONCLUSION

Both lipophilic and hydrophilic statins contribute to the prevention of liver cancer. Moreover, the efficacy was influenced by the region and the specific type of statins used.

Progress in Glioma Stem Cell Research

Glioblastoma multiforme (GBM) represents a diverse spectrum of primary tumors notorious for their resistance to established therapeutic modalities. Despite aggressive interventions like surgery, radiation, and chemotherapy, these tumors, due to factors such as the blood-brain barrier, tumor heterogeneity, glioma stem cells (GSCs), drug efflux pumps, and DNA damage repair mechanisms, persist beyond complete isolation, resulting in dismal outcomes for glioma patients. Presently, the standard initial approach comprises surgical excision followed by concurrent chemotherapy, where temozolomide (TMZ) serves as the foremost option in managing GBM patients. Subsequent adjuvant chemotherapy follows this regimen. Emerging therapeutic approaches encompass immunotherapy, including checkpoint inhibitors, and targeted treatments, such as bevacizumab, aiming to exploit vulnerabilities within GBM cells. Nevertheless, there exists a pressing imperative to devise innovative strategies for both diagnosing and treating GBM. This review emphasizes the current knowledge of GSC biology, molecular mechanisms, and associations with various signals and/or pathways, such as the epidermal growth factor receptor, PI3K/AKT/mTOR, HGFR/c-MET, NF-κB, Wnt, Notch, and STAT3 pathways. Metabolic reprogramming in GSCs has also been reported with the prominent activation of the glycolytic pathway, comprising aldehyde dehydrogenase family genes. We also discuss potential therapeutic approaches to GSC targets and currently used inhibitors, as well as their mode of action on GSC targets.

Statins in Cancer Prevention and Therapy

Statins, a class of HMG-CoA reductase inhibitors best known for their cholesterol-reducing and cardiovascular protective activity, have also demonstrated promise in cancer prevention and treatment. This review focuses on their potential applications in head and neck cancer (HNC), a common malignancy for which established treatment often fails despite incurring debilitating adverse effects. Preclinical and clinical studies have suggested that statins may enhance HNC sensitivity to radiation and other conventional therapies while protecting normal tissue, but the underlying mechanisms remain poorly defined, likely involving both cholesterol-dependent and -independent effects on diverse cancer-related pathways. This review brings together recent discoveries concerning the anticancer activity of statins relevant to HNC, highlighting their anti-inflammatory activity and impacts on DNA-damage response. We also explore molecular targets and mechanisms and discuss the potential to integrate statins into conventional HNC treatment regimens to improve patient outcomes.

Statin Use Ameliorates Survival in Oral Squamous Cell Carcinoma-Data from a Population-Based Cohort Study Applying Propensity Score Matching

The anti-cancer properties of statins have attracted much attention recently, but little is known about the prognostic role of statins in oral squamous cell carcinoma (OSCC). In a retrospective approach, we analyzed a population-based cohort of 602 OSCC patients with primary curative tumor resection to negative margins and concomitant neck dissection between 2005-2017. Long-term medication with statins was correlated with overall survival (OAS) as well as recurrence-free survival (RFS) using uni- and multivariable Cox regression. Additionally, propensity score matching was applied to adjust for confounders. Statin use was present in 96 patients (15.9%) at a median age of 65.7 years. Statin treatment correlated with ameliorated survival in multivariable Cox regression in the complete cohort (OAS: HR 0.664; 95% CI 0.467-0.945, p = 0.023; RFS: HR 0.662; 95% CI 0.476-0.920, p = 0.014) as well as matched-pair cohort of OSCC patients (OAS: HR 0.691; 95% CI 0.479-0.997, p = 0.048; RFS: HR 0.694; 95% CI 0.493-0.976, p = 0.036) when compared to patients not taking statins at time of diagnosis. These findings were even more pronounced by sub-group analysis in the matched-pair cohort (age < 70 years). These data indicate that statin use might ameliorate the oncological outcome in primarily resected OSCC patients, but prospective clinical trials are highly recommended.

Controlled microwave-assisted reactions: A facile synthesis of polyfunctionally substituted phthalazines as dual EGFR and PI3K inhibitors in CNS SNB-75 cell line

Brain tumors are stubborn cancers with poor prognosis and disappointing survival rates. Targeted cancer therapeutics with higher efficacy and lower resistance are highly demanded. An efficient one-pot synthesis of polyfunctionalized phthalazines derivatives was developed by reacting ethyl 1-aryl-5-cyano-1,6-dihydro-4-methyl-6-oxo-3-pyridazine-carboxylates with cinnamonitrile derivatives and the cycloaddition reaction of thieno[3,4-d]pyridazines with activated double or triple bond systems under controlled microwave heating with high yields. The resultant synthesized phthalazines (5a-e, 9 and 13) were tested for their in vitro anti-cancer activities by using in vitro one dose assay at National Cancer institute, USA. Only phthalazine (5b) showed broad spectrum anti-tumor activity against most tested cancer cell lines from all subpanels with mean % GI = 22.61. Interestingly, all tested compounds showed varying growth inhibitory activity against a particular cell line, CNS SNB-75 cell line, but (5b) exhibited the highest growth inhibitory activity against CNS-SNB-75 cell line with (GI% = 108.81) and (IC₅₀ = 3.703 ± 0.2) compared to erlotinib; (IC₅₀ = 12.5 ± 0.68). It caused Pre-G1 apoptosis and growth arrest at S phase. It also increased percentage of the total apoptotic cells in CNS-SNB-75 cell line (39.26%) compared to control cells (2.17%) in the annexin V-FITC experiment. It revealed pronounced EGFR inhibitory activity (IC₅₀ = 47.27 ± 2.41 ng/mL) compared to erlotinib (IC₅₀ = 30.7 ± 1.56 ng/mL). It also inhibited the different PI3K isoforms α, β, γ and δ (with IC₅₀ of 4.39, 13.6, 12.5 and 3.11 μg/mL, respectively compared to LY294002 (with IC₅₀ of 12.7, 8.57, 6.89 and 5.7 μg/mL, respectively). It also caused significant lower protein expression levels of pPI3K, AKT, pAKT and Bcl2 and higher protein expression levels of BAX, Casp3 and Casp9 when compared to untreated cells. Conclusion: Phthalazine (5b) may be an effective, convenient and safe anti-cancer agent acting via proapoptotic and dual EGFR and PI3K kinase inhibitory actions in CNS SNB-75 cell line.

Obesity-Specific Association of Statin Use and Reduced Risk of Recurrence of Early Stage NSCLC

Introduction

Statins, used for their lipid-lowering activity, have anti-inflammatory and anticancer properties as well. We evaluated this potential benefit of statin use in patients with NSCLC.

Methods

All 613 patients with pathologic stage 1 or 2 NSCLC who had lobectomy without neoadjuvant therapy at our institution during 2008 to 2015 were included. Association between presurgery statin use and overall survival and recurrence-free survival (RFS) was analyzed using Cox proportional hazards regression. Association of statin use with tumor transcriptome was evaluated in another 350 lung cancer cases.

Results

Univariable analyses did not reveal a statistically significant association of statin use with either overall survival or RFS, with hazard ratio equals to 1.19 and 0.70 (Wald p = 0.28 and 0.09), respectively. In subgroup analyses, significantly improved RFS was found in statin users, but only in overweight/obese patients (body mass index [BMI] > 25; n = 422), with univariable and multivariable hazard ratio of 0.49 and 0.46 (p = 0.005 and 0.002), respectively, but not in patients with BMI less than or equal to 25 (n = 191; univariable p = 0.21). Transcriptomes of tumor statin users had high expression of tumoricidal genes such as granzyme A and interferon-γ compared with those of nonusers among high- but not low-BMI patients with lung cancer.

Conclusions

Our study suggests that statins may improve the outcome of early stage NSCLC but only in overweight or obese patients. This benefit may stem from a favorable reprogramming of the antitumor immune response that statins perpetrate specifically in the obese.

Cholesterol-Lowering Drugs on Akt Signaling for Prevention of Tumorigenesis

Cholesterol has been reported to be accumulated in cancer cells. The metabolic dysregulation of the cholesterol is associated with tumor development and progression. The cholesterol-lowering drugs have been found to be involved in the prevention and treatment of various cancers. Akt, a serine/threonine kinase, can modulate the role of several downstream proteins involved in cell proliferation, migration, invasion, metabolism, and apoptosis. Since its involvement in several signaling pathways, its dysregulation is commonly reported in several cancers. Thus, targeting Akt could be an effective approach for cancer prevention and therapy. Cholesterol-lowering drugs have been found to affect the expression of Akt, and its activation in the cancer cells and thus have shown anticancer activity in different type of cancers. These drugs act on various signaling pathways such as PTEN/Akt, PI3k/Akt, Akt/NF-κB, Akt/FOXO1, Akt/mTOR, etc., which will be discussed in this article. This review article will discuss the significance of cholesterol in cancer cells, cholesterol-lowering drugs, the role of Akt in cancer cells, and the effects of cholesterol-lowering drugs on Akt in the prevention of therapy resistance and metastasis.

A Review of Red Yeast Rice, a Traditional Fermented Food in Japan and East Asia: Its Characteristic Ingredients and Application in the Maintenance and Improvement of Health in Lipid Metabolism and the Circulatory System

Red yeast rice has been used to produce alcoholic beverages and various fermented foods in China and Korea since ancient times; it has also been used to produce tofuyo (Okinawan-style fermented tofu) in Japan since the 18th century. Recently, monacolin K (lovastatin) which has cholesterol-lowering effects, was found in some strains of Monascus fungi. Since statins have been used world-wide as a cholesterol-lowering agent, processed foods containing natural statins are drawing attention as materials for primary prevention of life-style related diseases. In recent years, large-scale commercial production of red yeast rice using traditional solid-state fermentation has become possible, and various useful materials, including a variety of monascus pigments (polyketides) that spread as natural pigments, in addition to statins, are produced in the fermentation process. Red yeast rice has a lot of potential as a medicinal food. In this paper, we describe the history of red yeast rice as food, especially in Japan and East Asia, its production methods, use, and the ingredients with pharmacological activity. We then review evidence of the beneficial effects of red yeast rice in improving lipid metabolism and the circulatory system and its safety as a functional food.

CD99-PTPN12 Axis Suppresses Actin Cytoskeleton-Mediated Dimerization of Epidermal Growth Factor Receptor

Simple Summary

The epidermal growth factor receptor (EGFR) is activated through growth factor-dependent dimerization accompanied by functional reorganization of the actin cytoskeleton. Lee et al. demonstrate that CD99 activation by agonist ligands inhibits epidermal growth factor (EGF)-induced EGFR dimerization through impairment of cytoskeletal reorganization by protein tyrosine phosphatase non-receptor type 12 (PTPN12)-dependent c-Src/focal adhesion kinase (FAK) inactivation, thereby suppressing breast cancer growth.

Abstract

The epidermal growth factor receptor (EGFR), a member of ErbB receptor tyrosine kinase (RTK) family, is activated through growth factor-induced reorganization of the actin cytoskeleton and subsequent dimerization. We herein explored the molecular mechanism underlying the suppression of ligand-induced EGFR dimerization by CD99 agonists and its relevance to tumor growth in vivo. Epidermal growth factor (EGF) activated the formation of c-Src/focal adhesion kinase (FAK)-mediated intracellular complex and subsequently induced RhoA-and Rac1-mediated actin remodeling, resulting in EGFR dimerization and endocytosis. In contrast, CD99 agonist facilitated FAK dephosphorylation through the HRAS/ERK/PTPN12 signaling pathway, leading to inhibition of actin cytoskeletal reorganization via inactivation of the RhoA and Rac1 signaling pathways. Moreover, CD99 agonist significantly suppressed tumor growth in a BALB/c mouse model injected with MDA-MB-231 human breast cancer cells. Taken together, these results indicate that CD99-derived agonist ligand inhibits epidermal growth factor (EGF)-induced EGFR dimerization through impairment of cytoskeletal reorganization by PTPN12-dependent c-Src/FAK inactivation, thereby suppressing breast cancer growth.

Acute Statin Treatment Improves Antibody Accumulation in EGFR- and PSMA-Expressing Tumors

PURPOSE

Statins are cholesterol-depleting drugs used to treat patients with hypercholesterolemia. Preclinically, statins disrupt trafficking of receptors present at the cell membrane. Membrane receptors, defined as tumor biomarkers and therapeutic targets, are often internalized by an endocytic pathway. Indeed, receptor endocytosis and recycling are dynamic mechanisms that often affect receptor density at the cell surface. In therapies using monoclonal antibodies (mAb), a downregulation in receptor density at the cell surface decreases antibody binding to the extracellular domain of the membrane receptor. Here, we determined the potential of lovastatin, simvastatin, and rosuvastatin in preclinically modulating epidermal growth factor receptor (EGFR) and prostate-specific membrane antigen (PSMA) receptor density at the tumor cell surface.

EXPERIMENTAL DESIGN

Small-animal PET was used to study the binding of ⁸⁹Zr-labeled antibodies in ectopic xenografts. Ex vivo analyses were performed to determine changes in endocytic proteins, EGFR, and PSMA surface levels.

RESULTS

Acute statin treatment using lovastatin, simvastatin, or rosuvastatin enhanced tumors' avidity for the mAbs panitumumab, cetuximab, and huJ591. Statins temporarily modulated caveolin-1, cavin-1, endophilin, clathrin, and dynamin proteins in EGFR- and PSMA-overexpressing xenografts.

CONCLUSIONS

These data show the potential of statins as pharmacologic modulators of endocytic proteins for improved tumors' accumulation of mAbs. The translational significance of these findings lies in the potential of statins to temporarily modulate the heterogeneous presence of receptors at the cell membrane, a characteristic often associated with poor response in tumors to therapeutic antibodies.

Statins as Anticancer Agents in the Era of Precision Medicine

Statins are widely prescribed cholesterol-lowering drugs that inhibit HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate metabolic pathway. Multiple lines of evidence indicate that certain cancers depend on the mevalonate pathway for growth and survival, and, therefore, are vulnerable to statin therapy. However, these immediately available, well-tolerated, and inexpensive drugs have yet to be successfully repurposed and integrated into cancer patient care. In this review, we highlight recent advances and outline important considerations for advancing statins to clinical trials in oncology.

Clinical effects of simvastatin in chronic hepatitis C patients receiving sofosbuvir/daclatasvir combination. A randomized, placebo-controlled, double-blinded study

Aim of the study

Chronic hepatitis C (CHC) affects more than 71 million people worldwide. Many therapies containing different direct-acting antivirals (DAAs) are now used. However, lipid profile is considered an important outcome with DAAs. So, this study aimed to assess clinical effects of statins in CHC patients.

Material and methods

One hundred patients were recruited from Kobri El koba Armed Forces Hospital and randomly assigned to: the drug group (D;n = 50) receiving simvastatin 10 mg plus sofosbuvir 400 mg/daclatasvir 60 mg (SOF/DAC) daily for 12 weeks; and the placebo group (P; n = 50), receiving placebo plus the same (SOF/DAC) regimen. Sustained virological response at 12 weeks after treatment (SVR12), lipid profile, C-reactive protein (CRP) and fibrosis stage were assessed.

Results

One hundred treatment-naïve CHC patients completed 12 weeks of the protocol with no clinically significant side effects. There was an increase in SVR failure rate in P (10%) compared to D (only 2%) but not reaching statistical significant difference; SVR12 (p > 0.05). Logistic regression analysis showed that high baseline CRP, low baseline hemoglobin level and non-statin usage had an independent effect on increasing the probability of SVR failure in both groups; p = 0.03, p = 0.0028, p = 0.02, respectively.

Conclusions

Statins could have an irreplaceable role in successful treatment of CHC patients receiving sofosbuvir/daclatasvir.

Epidemiologic Analysis Along the Mevalonate Pathway Reveals Improved Cancer Survival in Patients Who Receive Statins Alone and in Combination With Bisphosphonates

PURPOSE

Cohort studies report associations between statin use and improved survival in patients with cancer. We used pharmacoepidemiologic methods to evaluate the survival of patients with cancer who received statins alone or in ostensibly synergistic drug combinations.

MATERIALS AND METHODS

Patients with cancer who were diagnosed from 2010 to 2013 were identified in a large health care claims database. The rate of all-cause death up to 1 year after diagnosis was compared by Cox proportional hazard regression. Sensitivity analyses included age stratification, statin type and intensity, and comparison with or without bisphosphonates and dipyridamole.

RESULTS

Among 312,907 identified patients with cancer, treatment groups included statin users (n = 65,440), nonstatin users who received medications that block cholesterol absorption (n = 9,289), and nonusers (n = 226,007). Statin use before diagnosis was associated with improved overall survival compared with no treatment (hazard ratio [HR], 0.85; 95% CI, 0.80 to 0.91) and specifically in patients with leukemia, lung, or renal cancers. Nonstatin users had increased overall survival compared with no treatment (HR, 0.73; 95% CI, 0.62 to 0.85); when stratified, this difference held true only for pancreatic cancer and leukemia. No differences were observed between statin and nonstatin groups. Bisphosphonate use alone had no effect (n = 4,528), but patients who used both statins and bisphosphonates (n = 4,090) had increased survival compared with no treatment (HR, 0.60; 95% CI, 0.45 to 0.81). The effect of the combination of dipyridamole and statin use (n = 651) was not significant compared with no treatment.

CONCLUSION

This study suggests that the combination of statins with drugs that affect isoprenylation, such as bisphosphonates, improves survival in patients with cancer. Consideration of pathway-specific pharmacology allows for hypotheses testing with the pharmacoepidemiologic approach. Prospective evaluation of these findings warrants clinical investigation and preclinical mechanistic studies.

Anti-cancer effect of doxorubicin is mediated by downregulation of HMG-Co A reductase via inhibition of EGFR/Src pathway

Doxorubicin is a widely used DNA damage-inducing anti-cancer drug. However, its use is limited by its dose-dependent side effects, such as cardiac toxicity. Cholesterol-lowering statin drugs increase the efficacy of some anti-cancer drugs. Cholesterol is important for cell growth and a critical component of lipid rafts, which are plasma membrane microdomains important for cell signaling. 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMG-CR) is a critical enzyme in cholesterol synthesis. Here, we show that doxorubicin downregulated HMG-CR protein levels and thus reduced levels of cholesterol and lipid rafts. Cholesterol addition attenuated doxorubicin-induced cell death, and cholesterol depletion enhanced it. Reduction of HMG-CR activity by simvastatin, a statin that acts as an HMG-CR inhibitor, or by siRNA-mediated HMG-CR knockdown enhanced doxorubicin cytotoxicity. Doxorubicin-induced HMG-CR downregulation was associated with inactivation of the EGFR-Src pathway. Furthermore, a high-cholesterol-diet attenuated the anti-cancer activity of doxorubicin in a tumor xenograft mouse model. In a multivulva model of Caenorhabditis elegans expressing an active-EGFR mutant, doxorubicin decreased hyperplasia more efficiently in the absence than in the presence of cholesterol. These data indicate that EGFR/Src/HMG-CR is a new pathway mediating doxorubicin-induced cell death and that cholesterol control could be combined with doxorubicin treatment to enhance efficacy and thus reduce side effects.

Effects of Resveratrol, Lovastatin and the mTOR-Inhibitor RAD-001 on Insulin-Induced Genomic Damage In Vitro

Diabetes mellitus (DM) is one of the major current health problems due to lifestyle changes. Before diagnosis and in the early years of disease, insulin blood levels are elevated. However, insulin generates low levels of reactive oxygen species (ROS) which are integral to the regulation of a variety of intracellular signaling pathways, but excess levels of insulin may also lead to DNA oxidation and DNA damage. Three pharmaceutical compounds, resveratrol, lovastatin and the mTOR-inhibitor RAD-001, were investigated due to their known beneficial effects. They showed protective properties against genotoxic damage and significantly reduced ROS after in vitro treatment of cultured cells with insulin. Therefore, the selected pharmaceuticals may be attractive candidates to be considered for support of DM therapy.

Marketed drugs used for the management of hypercholesterolemia as anticancer armament

The design of novel pharmacologic agents as well as their approval for sale in markets all over the world is a tedious and pricey process. Inevitably, oncologic patients commonly experience unwanted effects of new anticancer drugs, while the acquisition of clinical experience for these drugs is largely based on doctor–patient partnership which is not always effective. The repositioning of marketed non-antineoplastic drugs that hopefully exhibit anticancer properties into the field of oncology is a challenging option that gains ground and attracts preclinical and clinical research in an effort to override all these hindrances and minimize the risk for reduced efficacy and/or personalized toxicity. This review aims to present the anticancer properties of drugs used for the management of hypercholesterolemia. A global view of the antitumorigenicity of all marketed antihypercholesterolemic drugs is of major importance, given that atherosclerosis, which is etiologically linked to hypercholesterolemia, is a leading worldwide cause of morbidity and mortality, while hypercholesterolemia and tumorigenesis are known to be interrelated. In vitro, in vivo and clinical literature data accumulated so far outline the mechanistic basis of the antitumor function of these agents and how they could find application at the clinical setting.

Epidermal growth factor receptor in glioblastoma

Mutations in the epidermal growth factor receptor (EGFR) are commonly occurring in glioblastoma. Enhanced activation of EGFR can occur through a variety of different mechanisms, both ligand-dependent and ligand-independent. Numerous evidence has suggested that EGFR is overexpressed in most of primary glioblastomas and some of the secondary glioblastomas and is characteristic of more aggressive glioblastoma phenotypes. Additionally, recent studies have revealed that wild-type EGFR, and to a greater extent hyper-activating EGFR mutants induced a substantial upregulation of Fyn expression. Furthermore, it was determined that Fyn expression is upregulated across a panel of patient-derived glioblastoma stem cells (GSCs) relative to normal progenitor controls. Moreover, researchers are continuously involved in elucidation of novel mechanism linking EGFR EGFR-expressing glioblastoma. The present review highlights current aspects of EGFR receptor in glioblastoma and concludes that the concept of EGFR signaling and related receptors and associated factors is evolving, however, it needs detailed evaluation for future clinical applications in cancer patients.

Identification of drugs as single agents or in combination to prevent carcinoma dissemination in a microfluidic 3D environment

Experiments were performed in a modified microfluidic platform recapitulating part of the in vivo tumor microenvironment by co-culturing carcinoma cell aggregates embedded in a three-dimensional (3D) collagen scaffold with human umbilical vein endothelial cells (HUVECs). HUVECs were seeded in one channel of the device to initiate vessel-like structures in vitro prior to introducing the aggregates. The lung adenocarcinoma cell line A549 and the bladder carcinoma cell line T24 were tested. Dose-response assays of four drugs known to interfere with Epithelial Mesenchymal Transition (EMT) signaling pathways were quantified using relative dispersion as a metric of EMT progression. The presence of HUVECs in one channel induces cell dispersal in A549 which then can be inhibited by each of the four drugs. Complete inhibition of T24 aggregate dispersal, however, is not achieved with any single agent, although partial inhibition was observed with 10 μM of the Src inhibitor, AZD-0530. Almost complete inhibition of T24 dispersal in monoculture was achieved only when the four drugs were added in combination, each at 10 μM concentration. Coculture of T24 with HUVECs forfeits the almost-complete inhibition. The enhanced dispersal observed in the presence of HUVECs is a consequence of secretion of growth factors, including HGF and FGF-2, by endothelial cells. This 3D microfluidic co-culture platform provides an in vivo-like surrogate for anti-invasive and anti-metastatic drug screening. It will be particularly useful for defining combination therapies for aggressive tumors such as invasive bladder carcinoma.

The PathLinker app: Connect the dots in protein interaction networks

PathLinker is a graph-theoretic algorithm for reconstructing the interactions in a signaling pathway of interest. It efficiently computes multiple short paths within a background protein interaction network from the receptors to transcription factors (TFs) in a pathway. We originally developed PathLinker to complement manual curation of signaling pathways, which is slow and painstaking. The method can be used in general to connect any set of sources to any set of targets in an interaction network. The app presented here makes the PathLinker functionality available to Cytoscape users. We present an example where we used PathLinker to compute and analyze the network of interactions connecting proteins that are perturbed by the drug lovastatin.

Antiglioma effects of N6-isopentenyladenosine, an endogenous isoprenoid end product, through the downregulation of epidermal growth factor receptor

Malignant gliomas are highly dependent on the isoprenoid pathway for the synthesis of lipid moieties critical for cell proliferation. The isoprenoid derivative N6-isopentenyladenosine (iPA) displays pleiotropic biological effects, including a direct anti-tumor activity in several tumor models. The antiglioma effects of iPA was then explored in U87MG cells both in vitro and grafted in mice and the related molecular mechanism confirmed in primary derived patients' glioma cells. iPA powerfully inhibited tumor cell growth and induced caspase-dependent apoptosis through a mechanism involving a marked accumulation of the pro-apoptotic BIM protein and inhibition of EGFR. Indeed, activating AMPK following conversion into its iPAMP active form, iPA stimulated EGFR phosphorylation and ubiquitination along a proteasome-mediated pathway which was responsible for receptor degradation and its downstream signaling pathways inhibition, including the STAT3, ERK and AKT cascade. The inhibition of AMPK by compound C prevented iPA-mediated phosphorylation of EGFR, known to precede receptor loss. As expected the block of EGFR degradation, by exposure to the proteasome inhibitor MG132, significantly reduced iPA-induced cell death. Given the importance of receptor degradation in iPA-mediated cytotoxicity, we also documented that the EGFR expression levels in a panel of primary glioma cells confers them a high sensitivity to iPA treatment. In conclusion our study provides the first evidence of iPA antiglioma effect. Indeed, as glioma is driven by aberrant signaling of growth factor receptors, particularly the EGFR, iPA, alone or in association with EGFR targeted therapies, might be a promising therapeutic tool to achieve a potent anti-tumoral effect.

Structural insights of a hormone sensitive lipase homologue Est22

Hormone sensitive lipase (HSL) catalyzes the hydrolysis of triacylglycerols into fatty acids and glycerol, thus playing key roles in energy homeostasis. However, the application of HSL serving as a pharmaceutical target and an industrial biocatalyst is largely hampered due to the lack of high-resolution structural information. Here we report biochemical properties and crystal structures of a novel HSL homologue esterase Est22 from a deep-sea metagenomic library. Est22 prefers short acyl chain esters and has a very high activity with substrate p-nitrophenyl butyrate. The crystal structures of wild type and mutated Est22 with its product p-nitrophenol are solved with resolutions ranging from 1.4 Å to 2.43 Å. The Est22 exhibits a α/β-hydrolase fold consisting with a catalytic domain and a substrate-recognizing cap domain. Residues Ser188, Asp287, and His317 comprise the catalytic triad in the catalytic domain. The p-nitrophenol molecule occupies the substrate binding pocket and forms hydrogen bonds with adjacent residues Gly108, Gly109, and Gly189. Est22 exhibits a dimeric form in solution, whereas mutants D287A and H317A change to polymeric form, which totally abolished its enzymatic activities. Our study provides insights into the catalytic mechanism of HSL family esterase and facilitates the understanding for further industrial and biotechnological applications of esterases.

A phase I study of high-dose rosuvastatin with standard dose erlotinib in patients with advanced solid malignancies

BACKGROUND

Synergistic cytotoxicity with high-dose statins and erlotinib has been demonstrated in preclinical models across a number of tumour types. In this phase I study, we evaluated the safety and potential anti-tumour activity of escalating doses of rosuvastatin in combination with the standard clinical dose of erlotinib in heavily pretreated patients with advanced solid tumours.

METHODS

This was a single-center, phase I open-label study to determine the safety and recommended phase two dose (RPTD) of rosuvastatin in combination with 150 mg/day standard dose of erlotinib. Using a 3 + 3 study design and 28-day cycle, escalating doses of rosuvastatin from 1 to 8 mg/kg/day × 2 weeks (cycle 1) and 3 weeks (subsequent cycles) given concurrently with erlotinib were evaluated. In order to expand the experience and to gain additional safety and pharmacokinetic data, two expansions cohorts using concurrent or alternating weekly dosing regimens at the RPTD were also evaluated.

RESULTS

All 24 patients enrolled were evaluable for toxicity, and 22 for response. The dose-limiting toxicity (DLT) of reversible muscle toxicity was seen at the 2 mg/kg/day dose level. Maximal tolerated dose (MTD) was determined to be 1 mg/kg/day. Thirty-three percent of patients developed at least 1 ≥ grade 2 muscle toxicity (rhabdomyolysis: 1/24, myalgia: 7/24) resulting in one study-related death. Durable stable disease for more than 170 days was seen in 25 % of patients that received concurrent treatment and were evaluable for response (n = 16). Plasma erlotinib levels on study were unaffected by the addition of rosuvastatin.

CONCLUSIONS

The observed disease stabilization rate of 25 % with combination therapy in this heavily pretreated population is encouraging, however, the high levels of muscle toxicities observed limited this combination strategy.

RhoA Ambivalently Controls Prominent Myofibroblast Characteritics by Involving Distinct Signaling Routes

Introduction

RhoA has been shown to be beneficial in cardiac disease models when overexpressed in cardiomyocytes, whereas its role in cardiac fibroblasts (CF) is still poorly understood. During cardiac remodeling CF undergo a transition towards a myofibroblast phenotype thereby showing an increased proliferation and migration rate. Both processes involve the remodeling of the cytoskeleton. Since RhoA is known to be a major regulator of the cytoskeleton, we analyzed its role in CF and its effect on myofibroblast characteristics in 2 D and 3D models.

Results

Downregulation of RhoA was shown to strongly affect the actin cytoskeleton. It decreased the myofibroblast marker α-sm-actin, but increased certain fibrosis-associated factors like TGF-β and collagens. Also, the detailed analysis of CTGF expression demonstrated that the outcome of RhoA signaling strongly depends on the involved stimulus. Furthermore, we show that proliferation of myofibroblasts rely on RhoA and tubulin acetylation. In assays accessing three different types of migration, we demonstrate that RhoA/ROCK/Dia1 are important for 2D migration and the repression of RhoA and Dia1 signaling accelerates 3D migration. Finally, we show that a downregulation of RhoA in CF impacts the viscoelastic and contractile properties of engineered tissues.

Conclusion

RhoA positively and negatively influences myofibroblast characteristics by differential signaling cascades and depending on environmental conditions. These include gene expression, migration and proliferation. Reduction of RhoA leads to an increased viscoelasticity and a decrease in contractile force in engineered cardiac tissue.

The role of RhoA in vulvar squamous cell carcinoma: a carcinogenesis, progression, and target therapy marker

Ras homologue gene family member A (RhoA) is involved in tumor mobility, invasion, and metastasis. We detected RhoA expression in vulvar squamous cell carcinoma (VSCC) tissue, measured RhoA expression in the VSCC cell phenotype, and measured the expression of the relevant molecules after RhoA small interfering RNA (siRNA) transfection in SW962 cells. RhoA has a higher expression level in VSCC than normal vulva skin tissue and was positively associated with the International Federation of Gynecology and Obstetrics (FIGO) stage and differentiation; besides, VSCC patients with lymph node metastasis had higher positive RhoA expression. RhoA messenger RNA and protein expression was significantly reduced in the RhoA siRNA transfectants as compared with the negative control (NC) and mock-transfected cells (p < 0.05). The RhoA siRNA transfectants lead to low growth, G1 arrest, high apoptosis, low migration and invasion (p < 0.05), and suppressed lamellipodia formation as compared to NC and mock-transfected cells. Besides, matrix metalloproteinase-2 (MMP2), MMP9, and cyclinA1 protein expression was downregulated, while that of Bax was upregulated in the RhoA siRNA transfectants (p < 0.05). SW962 cell proliferation rates were significantly lovastatin dose-dependent. Lovastatin caused G1 arrest, high apoptosis, low migration and invasion (p < 0.05), and suppression of lamellipodia formation. Similar to the RhoA siRNA transfectants, lovastatin treatment downregulated RhoA, MMP2, MMP9, and cyclinA1 protein expression, while upregulating that of Bax as compared to that of the NC (p < 0.05). Abnormal RhoA expression in vulvar carcinoma is involved in tumor proliferation and invasion and may be a treatment target. The RhoA inhibitor lovastatin alters VSCC cell migration and proliferation and may be effective for treating VSCC.

Lipid dysregulation in hepatitis C virus, and impact of statin therapy upon clinical outcomes

The hepatitis C virus (HCV) is one of the most common causes of chronic liver disease and the leading indication for liver transplantation worldwide. Every aspect of the HCV life cycle is closely tied to human lipid metabolism. The virus circulates as a lipid-rich particle, utilizing lipoprotein cell receptors to gain entry into the hepatocyte. It has also been shown to upregulate lipid biosynthesis and impair lipid degradation, resulting in significant intracellular lipid accumulation and circulating hypocholesterolemia. Patients with chronic hepatitis C (CHC) are at increased risk of hepatic steatosis, fibrosis, and cardiovascular disease including accelerated atherosclerosis. HMG CoA Reductase inhibitors, or statins, have been shown to play an important role in the modulation of hepatic steatosis and fibrosis, and recent attention has focused upon their potential therapeutic role in CHC. This article reviews the hepatitis C viral life cycle as it impacts host lipoproteins and lipid metabolism. It then describes the pathogenesis of HCV-related hepatic steatosis, hypocholesterolemia and atherosclerosis, and finally describes the promising anti-viral and anti-fibrotic effects of statins, for the treatment of CHC.

Therapeutic Effects of Repurposed Therapies in Non-Small Cell Lung Cancer: What Is Old Is New Again

The recent emergence of targeted and immunotherapeutic agents has dramatically changed the management for patients with non-small cell lung cancer (NSCLC). Despite these advances, lung cancer is not exempt from the challenges facing oncology drug development, including the huge financial cost and the time required for drug implementation. Repositioning noncancer therapies with potential antineoplastic properties into new therapeutic niches is an alternative treatment strategy offering the possibility of saving money and time and improving outcomes. The goal of such a strategy is to deliver an effective drug with a favorable toxicity profile at a reduced cost. Preclinical models and observational data have demonstrated promising activity for many of these agents, and they are now being studied in prospective trials. We review the relevant published data regarding the therapeutic effects of metformin, statins, nonsteroidal anti-inflammatory drugs, β-blockers, and itraconazole in NSCLC, with a focus on the putative mechanisms of action and clinical data. As these drugs are increasingly being tested in clinical trials, we aim to highlight the salient challenges and future strategies to optimize this approach.

Combined treatment with troglitazone and lovastatin inhibited epidermal growth factor-induced migration through the downregulation of cysteine-rich protein 61 in human anaplastic thyroid cancer cells

Our previous studies have demonstrated that epidermal growth factor (EGF) can induce cell migration through the induction of cysteine-rich protein 61 (Cyr61) in human anaplastic thyroid cancer (ATC) cells. The aim of the present study was to determine the inhibitory effects of combined treatment with the peroxisome proliferator-activated receptor-γ (PPARγ) ligand troglitazone and the cholesterol-lowering drug lovastatin at clinically achievable concentrations on ATC cell migration. Combined treatment with 5 μM troglitazone and 1 μM lovastatin exhibited no cytotoxicity but significantly inhibited EGF-induced migration, as determined using wound healing and Boyden chamber assays. Cotreatment with troglitazone and lovastatin altered the epithelial-to-mesenchymal-transition (EMT) -related marker gene expression of the cells; specifically, E-cadherin expression increased and vimentin expression decreased. In addition, cotreatment reduced the number of filopodia, which are believed to be involved in migration, and significantly inhibited EGF-induced Cyr61 mRNA and protein expression as well as Cyr61 secretion. Moreover, the phosphorylation levels of 2 crucial signal molecules for EGF-induced Cyr61 expression, the cAMP response element-binding protein (CREB) and extracellular signal-regulated kinase (ERK), were decreased in cells cotreated with troglitazone and lovastatin. Performing a transient transfection assay revealed that the combined treatment significantly suppressed Cyr61 promoter activity. These results suggest that combined treatment with low doses of troglitazone and lovastatin effectively inhibits ATC cell migration and may serve as a novel therapeutic strategy for metastatic ATC.

Statin use is associated with a reduced risk of fibrosis progression in chronic hepatitis C

BACKGROUND & AIMS

Therapies that slow fibrosis progression in chronic liver disease are needed. Animal models have demonstrated that statins prevent the progression of hepatic fibrosis, but human data is lacking so far. We evaluated the association between statins and fibrosis progression in the HALT-C trial cohort.

METHODS

Subjects with chronic hepatitis C (CHC) and advanced hepatic fibrosis underwent serial liver biopsies over 3.5 years. The primary outcome was a ⩾ 2-point increase in the Ishak fibrosis score on at least one of two serial biopsies. We used complementary log-log regression analysis to assess the association between statins and fibrosis progression among subjects without baseline cirrhosis.

RESULTS

Fibrosis progression occurred in 3/29 (10%) statin users and 145/514 (29%) non-users. The unadjusted hazard ratio (HR) for fibrosis progression among statin users compared to non-users was 0.32 (95% CI 0.10-0.99). This association remained significant after adjusting for established predictors of histological outcome, including body mass index, platelets and hepatic steatosis (adjusted HR 0.31; 95% CI 0.10-0.97). The mean change in Ishak fibrosis score over the 3.5 year study period was -0.34 (SE 0.18) for statin users compared to +0.42 (SE 0.07) for non-users (p = 0.006, after adjustment for baseline fibrosis score).

CONCLUSIONS

Statin use is associated with a reduced risk of fibrosis progression in advanced CHC. Our findings suggest a potential role for statins in preventing liver disease progression.

Statins inhibit insulin-like growth factor action in first trimester placenta by altering insulin-like growth factor 1 receptor glycosylation

The rapid rise in obesity, metabolic syndrome and type 2 diabetes is one of the major healthcare problems of the Western world. Affected individuals are often treated with statins (3-hydroxy-3-methylglutaryl co-enzyme A [HMG CoA] reductase inhibitors) to reduce circulating cholesterol levels and the risk of developing cardiovascular disease; given the evolving demographic profile of these conditions, such drugs are increasingly prescribed to women of reproductive age. We have previously shown that exposure of placental tissue to statins inhibits the action of insulin-like growth factors (IGF)-I and -II which are key regulators of trophoblast proliferation and placental development. N-linked glycans in the IGF receptor, IGF1R, influence its presentation at the cell surface. This study aimed to determine whether statins, which are known to affect N-glycosylation, modulate IGF1R function in placenta. Treatment of first trimester villous tissue explants with statins (pravastatin or cerivastatin) or inhibitors of N-glycosylation (tunicamycin, deoxymannojirimycin or castanospermine) altered receptor distribution in trophoblast and attenuated proliferation induced by IGF-I or IGF-II (Ki67; P < 0.05, n = 5). Decreased binding of Phaseolus vulgaris lectin and phytohaemagglutinin to IGF1R immunoprecipitated from treated explants demonstrated reduced levels of complex N-linked glycans. Co-incubation of tissue explants with statins and farnesyl pyrophosphate (which increases the supply of dolichol intermediates), prevented statin-mediated disruption of IGF1R localization and reversed the negative effect on IGF-mediated trophoblast proliferation. These data suggest that statins attenuate IGF actions in the placenta by inhibiting N-linked glycosylation and subsequent expression of mature IGF1R at the placental cell surface.

Statin use and risk of nonmelanoma skin cancer: a nationwide study in Denmark

BACKGROUND

Evidence is conflicting regarding statin use and risk of basal cell (BCC) and squamous cell skin cancer (SCC).

METHODS

Using Danish nationwide registries, we identified all patients with incident BCC/SCC during 2005-2009 and matched them to population controls. We computed odds ratios (ORs) for BCC and SCC associated with statin use.

RESULTS

We identified 38,484 cases of BCC and 3724 cases of SCC. Statin ever use was associated with ORs of 1.09 (CI: 1.06-1.13) for BCC and 1.01 (CI: 0.91-1.11) for SCC.

CONCLUSIONS

Statin use was not associated with risk of SCC. Residual confounding plausibly explains the marginally increased risk of BCC.

Monensin inhibits epidermal growth factor receptor trafficking and activation: synergistic cytotoxicity in combination with EGFR inhibitors

Targeting the EGFR, with inhibitors such as erlotinib, represents a promising therapeutic option in advanced head and neck squamous cell carcinomas (HNSCC). However, they lack significant efficacy as single agents. Recently, we identified the ability of statins to induce synergistic cytotoxicity in HNSCC cells through targeting the activation and trafficking of the EGFR. However, in a phase I trial of rosuvastatin and erlotinib, statin-induced muscle pathology limited the usefulness of this approach. To overcome these toxicity limitations, we sought to uncover other potential combinations using a 1,200 compound screen of FDA-approved drugs. We identified monensin, a coccidial antibiotic, as synergistically enhancing the cytotoxicity of erlotinib in two cell line models of HNSCC, SCC9 and SCC25. Monensin treatment mimicked the inhibitory effects of statins on EGFR activation and downstream signaling. RNA-seq analysis of monensin-treated SCC25 cells demonstrated a wide array of cholesterol and lipid synthesis genes upregulated by this treatment similar to statin treatment. However, this pattern was not recapitulated in SCC9 cells as monensin specifically induced the expression of activation of transcription factor (ATF) 3, a key regulator of statin-induced apoptosis. This differential response was also demonstrated in monensin-treated ex vivo surgical tissues in which HMG-CoA reductase expression and ATF3 were either not induced, induced singly, or both induced together in a cohort of 10 patient samples, including four HNSCC. These results suggest the potential clinical utility of combining monensin with erlotinib in patients with HNSCC.

Effect of simvastatin on the resistance to EGFR tyrosine kinase inhibitors in a non-small cell lung cancer with the T790M mutation of EGFR

Although non-small cell lung cancer (NSCLC) tumors with activating mutations in the epidermal growth factor receptor (EGFR) are highly responsive to EGFR tyrosine kinase inhibitors (TKIs) including gefitinib and erlotinib, development of acquired resistance is almost inevitable. Statins show antitumor activity, but it is unknown whether they can reverse EGFR-TKIs resistance in NSCLC with the T790M mutation of EGFR. This study investigated overcoming resistance to EGFR-TKI using simvastatin. We demonstrated that addition of simvastatin to gefitinib enhanced caspase-dependent apoptosis in T790M mutant NSCLC cells. Simvastatin also strongly inhibited AKT activation, leading to suppression of β-catenin activity and the expression of its targets, survivin and cyclin D1. Both insulin treatment and AKT overexpression markedly increased p-β-catenin and survivin levels, even in the presence of gefitinib and simvastatin. However, inhibition of AKT by siRNA or LY294002 treatment decreased p-β-catenin and survivin levels. To determine the role of survivin in simvastatin-induced apoptosis of gefitinib-resistant NSCLC, we showed that the proportion of apoptotic cells following treatment with survivin siRNA and the gefitinib-simvastatin combination was greater than the theoretical additive effects, whereas survivin up-regulation could confer protection against gefitinib and simvastatin-induced apoptosis. Similar results were obtained in erlotinib and simvastatin-treated HCC827/ER cells. These findings suggest that survivin is a key molecule that renders T790M mutant NSCLC cells resistant to apoptosis induced by EGFR-TKIs and simvastatin. Overall, these data indicate that simvastatin may overcome EGFR-TKI resistance in T790M mutant NSCLCs via an AKT/β-catenin signaling-dependent down-regulation of survivin and apoptosis induction.

Arachidonic acid induction of Rho-mediated transendothelial migration in prostate cancer

BACKGROUND

Bone metastases in prostate cancer (CaP) result in CaP-related morbidity/mortality. The omega-6 polyunsaturated fatty acid (PUFA) arachidonic acid (AA) and lipophilic statins affect metastasis-like behaviour in CaP cells, regulating the critical metastatic step of CaP migration to the bone marrow stroma.

METHODS

Microscopic analysis and measurement of adhesion and invasion of CaP cells through bone marrow endothelial cells (BMEC) was undertaken with AA stimulation and/or simvastatin (SIM) treatment. Amoeboid characteristics of PC-3, PC3-GFP and DU-145 were analysed by western blotting and Rho assays.

RESULTS

The CaP cell lines PC-3, PC3-GFP and DU-145 share the ability to migrate across a BMEC layer. Specific amoeboid inhibition decreased transendothelial migration (TEM). AA stimulates amoeboid characteristics, driven by Rho signalling. Selective knock-down of components of the Rho pathway (RhoA, RhoC, Rho-associated protein kinase 1 (ROCK1) and ROCK2) showed that Rho signalling is crucial to TEM. Functions of these components were analysed, regarding adhesion to BMEC, migration in 2D and the induction of the amoeboid phenotype by AA. TEM was reduced by SIM treatment of PC3-GFP and DU-145, which inhibited Rho pathway signalling.

CONCLUSIONS

AA-induced TEM is mediated by the induction of a Rho-driven amoeboid phenotype. Inhibition of this cell migratory process may be an important therapeutic target in high-risk CaP.

Rho-kinase: regulation, (dys)function, and inhibition

In a variety of normal and pathological cell types, Rho-kinases I and II (ROCKI/II) play a pivotal role in the organization of the nonmuscle and smooth muscle cytoskeleton and adhesion plaques as well as in the regulation of transcription factors. Thus, ROCKI/II activity regulates cellular contraction, motility, morphology, polarity, cell division, and gene expression. Emerging evidence suggests that dysregulation of the Rho-ROCK pathways at different stages is linked to cardiovascular, metabolic, and neurodegenerative diseases as well as cancer. This review focuses on the current status of understanding the multiple functions of Rho-ROCK signaling pathways and various modes of regulation of Rho-ROCK activity, thereby orchestrating a concerted functional response.

Structural and functional analyses of a bacterial homologue of hormone-sensitive lipase from a metagenomic library

Intracellular mobilization of fatty acids from triacylglycerols in mammalian adipose tissues proceeds through a series of lipolytic reactions. Among the enzymes involved, hormone-sensitive lipase (HSL) is noteworthy for its central role in energy homeostasis and the pathogenic role played by its dysregulation. By virtue of its broad substrate specificity, HSL may also serve as an industrial biocatalyst. In a previous report, Est25, a bacterial homologue of HSL, was identified from a metagenomic library by functional screening. Here, the crystal structure of Est25 is reported at 1.49 Å resolution; it exhibits an α/β-hydrolase fold consisting of a central β-sheet enclosed by α-helices on both sides. The structural features of the cap domain, the substrate-binding pocket and the dimeric interface of Est25, together with biochemical and biophysical studies including native PAGE, mass spectrometry, dynamic light scattering, gel filtration and enzyme assays, could provide a basis for understanding the properties and regulation of hormone-sensitive lipase (HSL). The increased stability of cross-linked Est25 aggregates (CLEA-Est25) and their potential for extensive reuse support the application of this preparation as a biocatalyst in biotransformation processes.

Reduced esophageal cancer incidence in statin users, particularly with cyclo-oxygenase inhibition

AIM: To examine the association between statin use and the development of esophageal cancer

METHODS: We performed a systematic review and meta-analysis. Multiple databases (Pubmed, EMBASE, Cochrane Library, Web of Science, Wiley Interscience and Google Scholar) were systematically searched for studies reporting the association of statin use and the development of esophageal cancer. Literature searching and data abstraction were performed independently by two separate researchers. The quality of studies reviewed was evaluated using the Newcastle-Ottawa Quality assessment scale. Meta-analysis on the relationship between statin use and cancer incidence was performed. The effect of the combination of statin plus a cyclo-oxygenase inhibitor was also examined.

RESULTS: Eleven studies met eligibility criteria, 9 high and 2 medium quality. All were observational studies. Studies examining adenocarcinoma development in Barrett’s oesophagus included 317 cancers and 1999 controls, population-based studies examining all esophageal cancers included 371203 cancers and 6083150 controls. In the Barrett’s population the use of statins (OR = 0.57; 95%CI: 0.43-0.75) and cyclo-oxygenase inhibitors (OR = 0.59; 95%CI: 0.45-0.77) were independently associated with a reduced incidence of adenocarcinoma. Combined use of a statin plus cyclo-oxygenase inhibitor was associated with an even lower adenocarcinoma incidence (OR = 0.26; 95%CI: 0.1-0.68). There was more heterogeneity in the population-based studies but pooled adjusted data showed that statin use was associated with a lower incidence of all combined esophageal cancers (OR = 0.81; 95%CI: 0.75-0.88).

CONCLUSION: Statin use in patients with Barrett’s oesophagus is associated with a significantly lower incidence of adenocarcinoma. The chemopreventive actions of statins, especially combined with cyclo-oxygenase inhibitors deserve further exploration.

Activation of ErbB2 and Downstream Signalling via Rho Kinases and ERK1/2 Contributes to Diabetes-Induced Vascular Dysfunction

Diabetes mellitus leads to vascular complications but the underlying signalling mechanisms are not fully understood. Here, we examined the role of ErbB2 (HER2/Neu), a transmembrane receptor tyrosine kinase of the ErbB/EGFR (epidermal growth factor receptor) family, in mediating diabetes-induced vascular dysfunction in an experimental model of type 1 diabetes. Chronic treatment of streptozotocin-induced diabetic rats (1 mg/kg/alt diem) or acute, ex-vivo (10(-6), 10(-5) M) administration of AG825, a specific inhibitor of ErbB2, significantly corrected the diabetes-induced hyper-reactivity of the perfused mesenteric vascular bed (MVB) to the vasoconstrictor, norephinephrine (NE) and the attenuated responsiveness to the vasodilator, carbachol. Diabetes led to enhanced phosphorylation of ErbB2 at multiple tyrosine (Y) residues (Y1221/1222, Y1248 and Y877) in the MVB that could be attenuated by chronic AG825 treatment. Diabetes- or high glucose-mediated upregulation of ErbB2 phosphorylation was coupled with activation of Rho kinases (ROCKs) and ERK1/2 in MVB and in cultured vascular smooth muscle cells (VSMC) that were attenuated upon treatment with either chronic or acute AG825 or with anti-ErbB2 siRNA. ErbB2 likley heterodimerizes with EGFR, as evidenced by increased co-association in diabetic MVB, and further supported by our finding that ERK1/2 and ROCKs are common downstream effectors since their activation could also be blocked by AG1478. Our results show for the first time that ErbB2 is an upstream effector of ROCKs and ERK1/2 in mediating diabetes-induced vascular dysfunction. Thus, potential strategies aimed at modifying actions of signal transduction pathways involving ErbB2 pathway may prove to be beneficial in treatment of diabetes-induced vascular complications.

Role of Epidermal Growth Factor Receptor Inhibitors in Epidermal Growth Factor Receptor Wild-Type Non–Small-Cell Lung Cancer

Worldwide, the majority of patients with advanced non–small-cell lung cancer (NSCLC) do not have activating mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR). These wild-type patients comprise a significant proportion of those treated with inhibitors of this pathway, and data from randomized trials suggest that some of these wild-type patients will derive a modest benefit from these agents. Although the detection of an activating mutation predicts for a greater likelihood of response and longer progression-free survival from an EGFR tyrosine kinase inhibitor, currently there are no biomarkers that consistently and reproducibly predict for lack of benefit in wild-type patients. Several strategies to increase the efficacy of these inhibitors in wild-type NSCLC are the subject of ongoing investigations.

Lovastatin protects chondrocytes derived from Wharton's jelly of human cord against hydrogen-peroxide-induced in vitro injury

Our aim was to improve the survival and reduce the apoptosis of chondrocytes derived from mesenchymal stem cells from Wharton's jelly of human umbilical cord (WJMSCs) by Lovastatin supplementation under hydrogen-peroxide-induced injury conditions to simulate the osteoarthritic micro-environment. Chondrocytes were differentiated in vitro from WJMSCs. The cultured WJMSCs expressed CD90 (84.07%), CD105 (80.84%), OCT4 (26.90%), CD45 (0.42%) and CD34 (0.48%) as determined by flow cytometry. Increased aggregation of proteoglycans observed by Safranin-O staining accompanied by increased expression of COL2A1, ACAN, SOX9 and BGN shown by immunocytochemistry and reverse transcription with the polymerase chain reaction (PCR) confirmed the chondrogenic differentiation of the WJMSCs. The in vitro differentiated chondrocytes were subjected to oxidative stress by exposure to 200 μM hydrogen peroxide, either in the presence or absence of Lovastatin (2 μM) for 5 h. Lovastatin treatment resulted in decreased apoptosis, senescence and LDH release and in increased viability and proliferation of WJMSC-derived chondrocytes. Real time PCR analysis showed markedly up-regulated expression of prosurvival, proliferation and chondrogenic genes (BCL2L1, BCL2, AKT, PCNA, COL2A1, ACAN, SOX9 and BGN) and significantly down-regulated expression of pro-apoptotic genes (BAX, FADD) in the Lovastatin-treated group in comparison with injured cells. The reduced expression of VEGF and p53 as determined by enzyme-linked immunosorbent assay and PCR suggests the suitability of the use of Lovastatin in adjunct to WJMSC-derived chondrocytes for the treatment of osteoarthritis. We conclude that Lovastatin protects WJMSC-derived chondrocytes from hydrogen-peroxide-induced in vitro injury.

Lovastatin induces multiple stress pathways including LKB1/AMPK activation that regulate its cytotoxic effects in squamous cell carcinoma cells

Background

Cellular stress responses trigger signaling cascades that inhibit proliferation and protein translation to help alleviate the stress or if the stress cannot be overcome induce apoptosis. In recent studies, we demonstrated the ability of lovastatin, an inhibitor of mevalonate synthesis, to induce the Integrated Stress Response as well as inhibiting epidermal growth factor receptor (EGFR) activation.

Methodology/Principal Findings

In this study, we evaluated the effects of lovastatin on the activity of the LKB1/AMPK pathway that is activated upon cellular energy shortage and can interact with the above pathways. In the squamous cell carcinoma (SCC) cell lines SCC9 and SCC25, lovastatin treatment (1–25 µM, 24 hrs) induced LKB1 and AMPK activation similar to metformin (1–10 mM, 24 hrs), a known inducer of this pathway. Lovastatin treatment impaired mitochondrial function and also decreased cellular ADP/ATP ratios, common triggers of LKB1/AMPK activation. The cytotoxic effects of lovastatin were attenuated in LKB1 null MEFs indicating a role for this pathway in regulating lovastatin-induced cytotoxicity. Of clinical relevance, lovastatin induces synergistic cytotoxicity in combination with the EGFR inhibitor gefitinib. In LKB1 deficient (A549, HeLa) and expressing (SCC9, SCC25) cell lines, metformin enhanced gefitinib cytotoxicity only in LKB1 expressing cell lines while both groups showed synergistic cytotoxic effects with lovastatin treatments. Furthermore, the combination of lovastatin with gefitinib induced a potent apoptotic response without significant induction of autophagy that is often induced during metabolic stress inhibiting cell death.

Conclusion/Significance

Thus, targeting multiple metabolic stress pathways including the LKB1/AMPK pathway enhances lovastatin’s ability to synergize with gefitinib in SCC cells.

The differential effects of statins on the metastatic behaviour of prostate cancer

Background:

Although statins do not affect the incidence of prostate cancer (CaP), usage reduces the risk of clinical progression and mortality. Although statins are known to downregulate the mevalonate pathway, the mechanism by which statins reduce CaP progression is unknown.

Methods:

Bone marrow stroma (BMS) was isolated with ethical approval from consenting patients undergoing surgery for non-malignant disease. PC-3 binding, invasion and colony formation within BMS was assessed by standardised in vitro co-culture assays in the presence of different statins.

Results:

Statins act directly on PC-3 cells with atorvastatin, mevastatin, simvastatin (1 μℳ) and rosuvastatin (5 μℳ), but not pravastatin, significantly reducing invasion towards BMS by an average of 66.68% (range 53.93–77.04% P<0.05) and significantly reducing both number (76.2±8.29 vs 122.9±2.48; P=0.0055) and size (0.2±0.0058 mm²vs 0.27±0.012 mm²; P=0.0019) of colonies formed within BMS. Statin-treated colonies displayed a more compact morphology containing cells of a more epithelial phenotype, indicative of a reduction in the migrational ability of PC-3 cells. Normal PC-3 phenotype and invasive ability was recovered by the addition of geranylgeranyl pyrophosphate (GGPP).

Conclusion:

Lipophilic statins reduce the migration and colony formation of PC-3 cells in human BMS by inhibiting GGPP production, reducing the formation and the spread of metastatic prostate colonies.

Overcoming molecular mechanisms of resistance to first-generation epidermal growth factor receptor tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib have provided substantial benefits to patients with advanced non-small cell lung cancer (NSCLC). However resistance to these agents has emerged as a significant clinical issue; most patients who initially respond to treatment eventually experience relapse. The mechanisms underlying gefitinib and erlotinib resistance are multifactorial and several have been described. Clearly there is a need for novel and more effective therapies that can overcome resistance to the currently available TKIs. Several agents are in clinical development, including irreversible EGFR TKIs, inhibitors of the MET pathway, and others. In this review we discuss the various underlying mechanisms of gefitinib and erlotinib resistance and highlight the agents currently in clinical development that may have potential for overcoming this resistance.

Geranylgeranyl diphosphate synthase: an emerging therapeutic target

Proteins modified post-translationally by geranylgeranylation have been implicated in numerous cellular processes related to human disease. In recent years, the study of protein geranylgeranylation has advanced tremendously in both cellular and animal models. The advances in our understanding of the biological roles of geranylgeranylated proteins have been paralleled by advances in the medicinal chemistry of geranylgeranylation inhibitors such as those that target geranylgeranyl transferases I and II and geranylgeranyl diphosphate synthase (GGDPS). Although these findings provide the rationale for further development of geranylgeranylation as a therapeutic target, more advanced studies on the efficacy of this approach in various disease models will be required to support translation to clinical studies. This article attempts to describe the advances in (and the challenges of) validation of GGDPS as a novel therapeutic target and assesses the advantages of targeting GGDPS relative to other enzymes involved in geranylgeranylation.

A randomized phase II study of gefitinib plus simvastatin versus gefitinib alone in previously treated patients with advanced non-small cell lung cancer

PURPOSE

To evaluate the efficacy and safety of gefitinib plus simvastatin (GS) versus gefitinib alone (G) in previously treated patients with advanced non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Between May 2006 and September 2008, 106 patients (51% men, 75% adenocarcinoma, 50% never smoker) were randomly assigned to G alone (250 mg/d, n = 54) or GS (250 and 40 mg/d, respectively, n = 52). One cycle was 4 weeks of treatment. Therapy was continued until disease progression or intolerable toxicity was observed. The primary endpoint was response rate (RR). Secondary endpoints included toxicity, progression-free survival (PFS), and overall survival (OS).

RESULTS

The RR was 38.5% (95% CI, 25.3-51.7) for GS and 31.5% (95% CI, 19.1-43.9) for G. The median PFS was 3.3 months [M] (95% CI, 1.4-5.2M) for GS and 1.9M (95% CI, 1.0-2.8M) for G. The median OS was 13.6M (95% CI, 7.1-20.1M) for GS and 12.0M (95% CI, 7.8-16.2M) for G. In exploratory subgroup analysis, GS showed higher RR (40% vs. 0%, P = 0.043) and longer PFS (3.6M vs. 1.7M, P = 0.027) compared with G alone in patients with wild-type epidermal growth factor receptor (EGFR) nonadenocarcinomas. Adverse events in both arms were generally mild and mainly consisted of skin rashes.

CONCLUSIONS

Although no superiority of GS to G was demonstrated in this unselected NSCLC population, GS showed higher RR and longer PFS compared with G alone in patients with wild-type EGFR nonadenocarcinomas. Simvastatin may improve the efficacy of gefitinib in that subgroup of gefitinib-resistant NSCLC patients.