Suppression of invasion and MMP-9 expression in NIH 3T3 and v-H-Ras 3T3 fibroblasts by lovastatin through inhibition of ras isoprenylation

Assessing the role of lipid-lowering therapy on multi-cancer prevention: A mendelian randomization study

Background: Statin use for cancer prevention has raised wide attention but the conclusions are still controversial. Whether statins use have exact causal effects on cancer prevention remains unclear. Methods: Based on the Genome-Wide Association Studies (GWAS) datasets from the large prospective UK Biobank and other consortium databases, two-sample mendelian randomization (MR) analysis was conducted to explore the causal effects of statins use on varied site-specific cancer risks. Five MR methods were applied to investigate the causality. The stability, heterogeneity, and pleiotropy of MR results were also evaluated. Results: The atorvastatin use could increase the risk of colorectal cancer (odd ratio (OR) = 1.041, p = 0.035 by fixed-effects inverse variance weighted (IVW) method (IVW_FE), OR = 1.086, p = 0.005 by weighted median; OR = 1.101, p = 0.048 by weighted mode, respectively). According to the weighted median and weighted mode, atorvastatin could modestly decrease the risk of liver cell cancer (OR = 0.989, p = 0.049, and OR = 0.984, p = 0.004, respectively) and head and neck cancer (OR = 0.972, p = 0.020). Besides, rosuvastatin use could reduce the bile duct cancer risk by 5.2% via IVW_EF method (OR = 0.948, p = 0.031). No significant causality was determined in simvastatin use and pan-cancers via the IVW_FE or multiplicative random-effects IVW (IVW_MRE) method if applicable (p > 0.05). There was no horizontal pleiotropy observed in the MR analysis and the leave-one-out analysis proved the stability of the results. Conclusion: The causalities between statin use and cancer risk were only observed in colorectal cancer and bile duct cancer in the European ancestry population. Future works are warranted to provide more robust evidence for supporting statin repurposing for cancer prevention.

Association between Statin Use and Survival in Cancer Patients with Brain Metastasis: Retrospective Analysis from the Chinese Population

Brain metastasis predicts a worse clinical outcome in cancer patients. Emerging observational evidence suggests that statin use has a protective role in overall cancer prevention. Whether statin use could also be a supplementary treatment for advanced-stage cancers remains under researched and controversial. Data for cancer patients with brain metastasis were selected from the linked electronic medical care records of the West China Hospital between October 2010 and July 2019. Fisher’s exact chi-square test was used to compare the differences between cohorts. Multivariate Cox analysis was conducted to adjust the potential confounders in evaluating the role of statin use in the overall survival (OS) of cancer patients with brain metastasis. There were 4510 brain metastatic patients included in this retrospective study. The overall statin use rate in our patients was 5.28% (219 cases/4510 cases). Compared with the non-statin use cohort, patients who received statin therapy showed a decreased Karnofsky performance score (KPS, p < 0.001) and lower high-density lipoprotein (HDL, p = 0.020) but higher body mass index (BMI, p = 0.002) and triglyceride (TG, p < 0.001) at admission. There was no association between statin use and the OS of the cancer patients with brain metastasis (Hazard ratio (HR) = 0.90, 95% confidence interval (CI): 0.73−1.07, p = 0.213) during the univariate analysis. However, after adjusting for baseline patient characteristics, metabolism indicators, and cancer-specific factors, statin use was shown to have a significant protective role, aiding the survival of the cancer patients with brain metastasis (adjustHR = 0.82, 95%CI: 0.69−0.99, p = 0.034). Our results highlight that statin use shows significant survival benefits in cancer patients with brain metastasis. However, future research is needed to validate our findings.

Mevastatin in colon cancer by spectroscopic and microscopic methods - Raman imaging and AFM studies

One of the most important areas of medical science is oncology, which is responsible for both the diagnostics and treatment of cancer diseases. Simultaneously one of the main challenges of oncology is the development of modern drugs effective in the fight against cancer. Statins are a group of biologically active compounds with the activity of 3-hydroxy-3-methyl glutaryl-CoA reductase inhibitors, an enzyme catalyzing the reduction of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) to mevalonic acid. By acting on this enzyme, statins inhibit the endogenous cholesterol synthesis which in turn causes the reduction of its systemic concentrations. However, in vitro and in vivo studies confirm also the cytostatic and cytotoxic effects of statins against various types of cancer cells including colon cancer. In the presented studies the influence of mevastatin on cancerous colon cells CaCo-2 by Raman spectroscopy and imaging is discussed and compared with biochemistry characteristic for normal colon cells CCD-18Co. Based on vibrational features of colon cells: normal cells CCD-18Co, cancerous cells CaCo-2 and cancerous cells CaCo-2 treated by mevastatin in different concentrations and incubation times we have confirmed the influence of this statin on biochemistry composition of cancerous human colon cells. Moreover, the spectroscopic results for colon normal cells and cancerous cells based on data typical for nucleic acids, proteins, lipids have been compared. The cytotoxisity of mevastatin was determined by using XTT tests.

Predicting the effect of statins on cancer risk using genetic variants from a Mendelian randomization study in the UK Biobank

Laboratory studies have suggested oncogenic roles of lipids, as well as anticarcinogenic effects of statins. Here we assess the potential effect of statin therapy on cancer risk using evidence from human genetics. We obtained associations of lipid-related genetic variants with the risk of overall and 22 site-specific cancers for 367,703 individuals in the UK Biobank. In total, 75,037 individuals had a cancer event. Variants in the HMGCR gene region, which represent proxies for statin treatment, were associated with overall cancer risk (odds ratio [OR] per one standard deviation decrease in low-density lipoprotein [LDL] cholesterol 0.76, 95% confidence interval [CI] 0.65-0.88, p=0.0003) but variants in gene regions representing alternative lipid-lowering treatment targets (PCSK9, LDLR, NPC1L1, APOC3, LPL) were not. Genetically predicted LDL-cholesterol was not associated with overall cancer risk (OR per standard deviation increase 1.01, 95% CI 0.98-1.05, p=0.50). Our results predict that statins reduce cancer risk but other lipid-lowering treatments do not. This suggests that statins reduce cancer risk through a cholesterol independent pathway.

[Effects of farnesyltransferase silencing on the migration and invasion of tongue squamous cell carcinoma]

OBJECTIVE

This study aimed to explore the effects of silencing farnesyltransferase (FTase) on the migration and invasion of tongue squamous cell carcinoma (TSCC) through RNA interference.

METHODS

TSCC cells (CAL27 and SCC-4) were cultured in vitro and then transfected with siRNA to silence FTase expression. The tested cells were categorized as follows: experimental group (three RNA interference groups), negative control group, and blank control group. mRNA expression of FTase and HRAS in each group was analyzed by quantitative real-time polymerase chain reaction. On the basis of FTase mRNA expression, the optimum interference group (highest silencing efficiency) was selected as the experimental group for further study. The protein expression of FTase, HRAS, p65, p-p65(S536), matrix metalloprotein-9 (MMP-9), hypoxia inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF) was analyzed by Western blot. The invasion and migration abilities of TSCC cells were determined by Transwell invasion assay and cell wound healing assay.

RESULTS

The mRNA and protein expression of FTase in the experimental group decreased compared with that in the negative control and blank control groups (P<0.05). The mRNA and protein expression of HRAS was not significantly different among the groups (P>0.05). In the experimental group, the protein expression of p-p65(S536), MMP-9, HIF-1α, and VEGF decreased (P<0.05), whereas that of p65 had no significant change (P>0.05). The migration and invasion abilities of the experimental group were inhibited significantly (P<0.05).

CONCLUSIONS

Silencing FTase in vitro could effectively downregulate its expression in TSCC cell lines and reduce the migration and invasion abilities to a certain extent. FTase could be a new gene therapy target of TSCC, and this research provided a new idea for the clinical treatment of TSCC.

TPK1 as a predictive marker for the anti-tumour effects of simvastatin in gastric cancer

The potential anti-tumour role of statins has been reported in various cancer types, including gastric cancer (GC). However, there are no biomarkers to identify patients who may benefit most from this treatment. We tested the effects of statins on 8 GC cell lines. Genes differentially expressed in simvastatin-sensitive and -resistant cell lines were used to identify potential biomarkers of simvastatin sensitivity. Patient-derived cell lines were used to mimic in vivo conditions. In simvastatin-sensitive SNU-5 cells, the levels of the PARP and cleaved caspase-3 apoptosis markers increased upon exposure to simvastatin. The levels of the PARP and cleaved caspase-3 levels were unchanged by simvastatin exposure in simvastatin-resistant SNU-668 cells. The proportion of apoptotic cells was increased in SNU-5 cells but not in SNU-668 cells under the same drug exposure conditions. Comparison of differentially expressed genes (DEGs) in sensitive and resistant cell lines identified 31 genes potentially involved in the cellular response to simvastatin. We confirmed that RNA expression of the TPK1 DEG was significantly increased in simvastatin-sensitive cell lines. TPK1 knockdown in a simvastatin-sensitive GC SNU5 cell line, decreased the anti-tumour effects of simvastatin, while TPK1 overexpression enhanced the anti-tumour effect of simvastatin. Therefore, TPK1 expression can be used as a predictive marker of the anti-tumour effects of statin treatment in patients with cancer, especially in those with GC.

Nobiletin inhibits human osteosarcoma cells metastasis by blocking ERK and JNK-mediated MMPs expression

Nobiletin, a polymethoxyflavone, has a few pharmacological activities, including anti-inflammation and anti-cancer effects. However, its effect on human osteosarcoma progression remains uninvestigated. Therefore, we examined the effectiveness of nobiletin against cellular metastasis of human osteosarcoma and the underlying mechanisms. Nobiletin, up to 100 μM without cytotoxicity, significantly decreased motility, migration and invasion as well as enzymatic activities, protein levels and mRNA expressions of matrix metalloproteinase (MMP)-2 and MMP-9 in U2OS and HOS cells. In addition to inhibition of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), the inhibitory effect of nobiletin on the DNA-binding activity of the transcription factor nuclear factor-kappa B (NF-κB), cAMP response element-binding protein (CREB), and specificity protein 1 (SP-1) in U2OS and HOS cells. Co-treatment with ERK and JNK inhibitors and nobiletin further reduced U2OS cells migration and invasion. These results indicated that nobiletin inhibits human osteosarcoma U2OS and HOS cells motility, migration and invasion by down-regulating MMP-2 and MMP-9 expressions via ERK and JNK pathways and through the inactivation of downstream NF-κB, CREB, and SP-1. Nobiletin has the potential to serve as an anti-metastatic agent for treating osteosarcoma.

Modular Immune Organoids with Integrin Ligand Specificity Differentially Regulate Ex Vivo B Cell Activation

Germinal centers are dynamic structures within lymphoid tissues, which develop once B cells receive activating signals from surrounding immune cells. Germinal center B cells are small in number, heterogeneous, and prone to rapid apoptosis unless selected by the body to form memory B cells. Despite extensive research in the B cell differentiation process, the role of the lymphoid niche, in particular integrin ligands, in the development of early germinal center-like phenotype remains unclear. Here, we report a biomaterials-based modular immune organoid that enables development of early germinal-center phenotype in an integrin ligand-specific manner. We demonstrate the differential role of integrin α4β1- and αvβ3-binding ligands in the induction of GL7+ (GC-like) and GL7- (non-GC-like) phenotype in differentiating B cells while in the presence of CD40 ligand and interleukin-4. We further demonstrate the role of integrin ligand specificities in clustering of β3 integrin and B cell receptor on the surface of differentiated B cells in 3D organoids as compared to the classic 2D cocultures. The study demonstrates that biomaterials-based immune organoids represent an ex vivo platform technology, which recapitulates certain aspects of GC biology to understand the process of B cell differentiation and induction of immunological responses. This platform is particularly useful in understanding the role of selective biomolecular signals and the temporal dependency of immune responses to these signals.

Preoperative statin use is not associated with improvement in survival after glioblastoma surgery

Cohort studies have suggested that the use of statins is associated with decreased risk of glioma formation and mortality. Here, a cohort of patients with glioblastoma multiforme (GBM) was analyzed to further investigate associations between preoperative use of statins and recurrence, and progression free and overall survival. Patients who had surgery for GBM (N=284) were followed up for a median of 18.1months. Seventy-eight patients were taking statins preoperatively while the rest were not. Cox proportional hazards models adjusted for several covariates of interest were applied before and after propensity score matching. Compared with statin users, those not taking the lipid-lowering drugs had similar progression free survival before (hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.70-1.26; p=0.68) and after propensity score matching (HR 0.95, 95% CI 0.67-1.35; p=0.68). Mortality was similar between both groups of patients before (HR 0.94, 95% CI 0.70-1.22; p= 0.73) and after propensity score matching (HR 1.13, 95% CI 0.78-1.64; p=0.49). Age and dexamethasone use were independent prognostic factors of survival. Contrary to previously published evidence, this study could not find an association between preoperative statin use and longer survival in GBM patients. Due to the small number of patients and retrospective nature of the study, further work is needed to understand the role of perioperative statins in GBM patients.

Exploitation of pleiotropic actions of statins by using tumour-targeted delivery systems

Statins are drugs traditionally used to lower cholesterol levels in blood. At concentrations 100- to 500-fold higher than those needed for reaching cholesterol lowering activity, they have anti-tumour activity. This anti-tumour activity is based on statins pleiotropic effects derived from their ability to inhibit the mevalonate synthesis and include anti-proliferative, pro-apoptotic, anti-angiogenic, anti-inflammatory, anti-metastatic actions and modulatory effects on intra-tumour oxidative stress. Thus, in this review, we summarise the possible pleiotropic actions of statins involved in tumour growth inhibition. Since the administration of these high doses of statins is accompanied by severe side effects, targeted delivery of statins seems to be the appropriate strategy for efficient application of statins in oncology. Therefore, we also present an overview of the current status of targeted delivery systems for statins with possible utilisation in oncology.

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.

Bisphosphonates inhibit cell functions of HUVECs, fibroblasts and osteogenic cells via inhibition of protein geranylgeranylation

OBJECTIVES

Bisphosphonate-associated osteonecrosis of the jaw is a severe side effect in patients receiving nitrogen-containing bisphosphonates (N-BPs). One characteristic is its high recurrence rate; therefore, basic research for new therapeutic options is necessary. N-BPs inhibit the farnesylpyrophosphate synthase in the mevalonate pathway causing a depletion of the cellular geranylgeranyl pool, resulting in a constriction of essential functions of different cell lines. Geranylgeraniol (GGOH) has been proven to antagonise the negative biological in vitro effects of bisphosphonates.

MATERIAL AND METHODS

This study analyses the influence of the isoprenoids eugenol, farnesol, R-limonene, menthol and squalene on different functions of zoledronate-treated human umbilicord vein endothelial cells (HUVEC), fibroblasts and osteogenic cells. In addition to the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl 2H-tetrazolium bromide (MTT) vitality test, the migration capacity was analysed by scratch wound assay and the morphological architecture of the treated cells by phallacidin staining.

RESULTS

In contrast to GGOH, none of the other tested isoprenoids were able to prevent cells from having negative zoledronate effects.

CONCLUSIONS

Despite structural analogy to GGOH, the investigated isoprenoids are not able to prevent the N-BP effect. The negative impact of zoledronate on fibroblasts, HUVEC and osteogenic cells is due to inhibition of protein geranylgeranylation since the substitution of squalene and farnesyl did not have any effect on viability and wound healing capacity whereas GGOH did reduce the negative impact.

CLINICAL RELEVANCE

These data suggest the importance and exclusiveness of the mevalonate pathway intermediate GGOH as a potential therapeutic approach to bisphosphonate-associated osteonecrosis of the jaws.

The spectrum of statin therapy in cancer patients: is there a need for further investigation?

Although our understanding of the relationship between cancer and statin use continues to improve, it remains a complex association requiring further research focusing on both biologic and clinical end points in a wide range of patient populations. To date, most of the published results are from observational studies detailing the risk of incident cancers or from randomized controlled trials with cardiovascular primary end points and cancer only as a secondary end point. Although there is certainly great value in the information obtained from observational studies, they cannot prove a causal link between statins and cancer, and it would then seem appropriate to design and implement clinical trials. Such studies should consider three main end products of the mevalonate pathway (cholesterol, geranyl pyrophosphate, and farnesyl pyrophosphate) from a mechanistic perspective, as well as the potential for cancer cell mediation with statin use, in addition to pertinent clinical end points including cancer incidence and mortality.

Simvastatin inhibits proliferation and induces apoptosis in human lung cancer cells

Lung cancer is the one of the most frequent causes of malignant tumors. In recent years, it has been documented that statins have anticancer and cancer chemopreventive properties. However, the mechanism of simvastatin on lung cancer is still unclear. In this study, the human lung cancer cell line A549 cells were incubated with simvastatin. Simvastatin inhibited the survival of A549 cells in a dose-dependent manner, decreased Bcl-2 protein expression, and increased Bax protein expression time and dose dependently. In addition, simvastatin blocked cells in the G1 phase of the cell cycle, downregulated cyclin D1 and CDKs protein expression, mediated the mitochondria-dependent caspase cascade by increasing caspase-3, -8, and -9 mRNA and protein expression, downregulated Xiap levels to induce cells apoptosis. Importantly, simvastatin suppressed decreased MMP-9 protein expression and suppressed NF-κB activation in A549 cells. Taken together, these results showed that the anticancer effect of simvastatin in lung cancer A549 cells via the inhibiting cell proliferation, influencing the cell cycle, downregulating cyclin D1 and CDKs expression, inducing apoptosis, and decreasing MMP-9 levels, possibly by inhibiting the activation of NF-κB. Statins contribute to lung cancer therapy and may be an ideal anticancer and cancer chemopreventive agent for lung cancer.

Pharmacological actions of statins: a critical appraisal in the management of cancer

Statins, among the most commonly prescribed drugs worldwide, are cholesterol-lowering agents used to manage and prevent cardiovascular and coronary heart diseases. Recently, a multifaceted action in different physiological and pathological conditions has been also proposed for statins, beyond anti-inflammation and neuroprotection. Statins have been shown to act through cholesterol-dependent and -independent mechanisms and are able to affect several tissue functions and modulate specific signal transduction pathways that could account for statin pleiotropic effects. Typically, statins are prescribed in middle-aged or elderly patients in a therapeutic regimen covering a long life span during which metabolic processes, aging, and concomitant novel diseases, including cancer, could occur. In this context, safety, toxicity, interaction with other drugs, and the state of health have to be taken into account in subjects treated with statins. Some evidence has shown a dichotomous effect of statins with either cancer-inhibiting or -promoting effects. To date, clinical trials failed to demonstrate a reduced cancer occurrence in statin users and no sufficient data are available to define the long-term effects of statin use over a period of 10 years. Moreover, results from clinical trials performed to evaluate the therapeutic efficacy of statins in cancer did not suggest statin use as chemotherapeutic or adjuvant agents. Here, we reviewed the pharmacology of the statins, providing a comprehensive update of the current knowledge of their effects on tissues, biological processes, and pathological conditions, and we dissected the disappointing evidence on the possible future use of statin-based drugs in cancer therapy.

Statins and prostate cancer: molecular and clinical aspects

The field of the potential applications of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) beyond their unambiguous cardiovascular beneficial effects is steadily increasing. In this regard, statins have also been shown to possess anti-inflammatory, immunomodulatory, antioxidant and growth inhibitory properties. Regarding their role in carcinogenesis, both preclinical and clinical studies report conflicting results. Intriguingly, accumulating evidence suggests that statins may relate to decreased prostate cancer incidence and recurrence risk. However, data from clinical studies seem to be still weak and are confounded by several factors. Nonetheless, preclinical data suggest that statins might exert a chemopreventive role against prostate cancer by inhibiting the proliferation and inducing apoptosis of prostate cancer cells and also inhibiting angiogenesis, inflammation and metastasis. Cholesterol lowering as well as statin pleiotropy through inhibition of the synthesis of isoprenoids have both been implicated in their anticancer properties. In this review, we discuss the preclinical and clinical evidence supporting the preventive or potentially harmful effects of statins on prostate tumourigenesis and conclude that statins should not be recommended for the prevention of prostate cancer development or progression based on the current data.

Cell surface heparan sulfates mediate internalization of the PWWP/HATH domain of HDGF via macropinocytosis to fine-tune cell signalling processes involved in fibroblast cell migration

HDGF (hepatoma-derived growth factor) stimulates cell proliferation by functioning on both sides of the plasma membrane as a ligand for membrane receptor binding to trigger cell signalling and as a stimulator for DNA synthesis in the nucleus. Although HDGF was initially identified as a secretory heparin-binding protein, the biological significance of its heparin-binding ability remains to be determined. In the present study we demonstrate that cells devoid of surface HS (heparan sulfate) were unable to internalize HDGF, HATH (N-terminal domain of HDGF consisting of amino acid residues 1-100, including the PWWP motif) and HATH(K96A) (single-site mutant form of HATH devoid of receptor binding activity), suggesting that the binding of HATH to surface HS is important for HDGF internalization. We further demonstrate that both HATH and HATH(K96A) could be internalized through macropinocytosis after binding to the cell surface HS. Interestingly, HS-mediated HATH(K96A) internalization is found to exhibit an inhibitory effect on cell migration and proliferation in contrast with that observed for HATH action on NIH 3T3 cells, suggesting that HDGF exploits the innate properties of both cell surface HS and membrane receptor via the HATH domain to affect related cell signalling processes. The present study indicates that MAPK (mitogen-activated protein kinase) signalling pathways could be affected by the HS-mediated HATH internalization to regulate cell migration in NIH 3T3 fibroblasts, as judged from the differential effect of HATH and HATH(K96A) treatment on the expression level of matrix metalloproteases.

Targets of chymase inhibitors

INTRODUCTION

Chymase converts angiotensin I to angiotensin II and it can also convert precursors of TGF-β and MMP-9 to their active forms. Therefore, diseases related to angiotensin II TGF-β, and MMP-9 could potentially be treated with chymase inhibitors.

AREAS COVERED

This review discusses the appropriate targets and safety of chymase inhibitors. Six diseases with notable mortality or morbidity as targets of chymase inhibitors are focused on; abdominal aortic aneurysms (AAAs), nephropathy and retinopathy, cardiomyopathy, nonalcoholic steatohepatitis (NASH), organ fibrosis and intestinal diseases.

EXPERT OPINION

If chymase inhibition proves to be a useful strategy for the attenuation of angiotensin II, TGF-β and MMP-9 in vivo, the application of chymase inhibitors is likely to become widespread in various diseases in the clinical setting. Chymase inhibitors are anticipated not to interfere with the homeostasis of resting tissues, that is, those not affected by injury or inflammation.

Inhibition of GGTase-I and FTase disrupts cytoskeletal organization of human PC-3 prostate cancer cells

The mevalonate synthesis pathway produces intermediates for isoprenylation of small GTPases, which are involved in the regulation of actin cytoskeleton and cell motility. Here, we investigated the role of the prenylation transferases in the regulation of the cytoskeletal organization and motility of PC-3 prostate cancer cells. This was done by using FTI-277, GGTI-298 or NE-10790, the specific inhibitors of FTase (farnesyltransferase), GGTase (geranylgeranyltransferase)-I and -II, respectively. Treatment of PC-3 cells with GGTI-298 and FTI-277 inhibited migration and invasion in a time- and dose-dependent manner. This was associated with disruption of F-actin organization and decreased recovery of GFP-actin. Immunoblot analysis of various cytoskeleton-associated proteins showed that the most striking change in GGTI-298- and FTI-277-treated cells was a markedly decreased level of total and phosphorylated cofilin, whereas the level of cofilin mRNA was not decreased. The treatment of PC-3 cells with GGTI-298 also affected the dynamics of GFP-paxillin and decreased the levels of total and phosphorylated paxillin. The levels of phosphorylated FAK (focal adhesion kinase) and PAK (p-21-associated kinase)-2 were also lowered by GGTI-298, but levels of paxillin or FAK mRNAs were not affected. In addition, GGTI-298 had a minor effect on the activity of MMP-9. RNAi knockdown of GGTase-Ibeta inhibited invasion, disrupted F-actin organization and decreased the level of cofilin in PC-3 cells. NE-10790 did not have any effect on PC-3 prostate cancer cell motility or on the organization of the cytoskeleton. In conclusion, our results demonstrate the involvement of GGTase-I- and FTase-catalysed prenylation reactions in the regulation of cytoskeletal integrity and motility of prostate cancer cells and suggest them as interesting drug targets for development of inhibitors of prostate cancer metastasis.

Statins use and risk for brain metastasis from lung cancer

Laboratory data suggest an association between statins and risk of brain metastasis (BM) in patients diagnosed with lung cancer. Our retrospective cohort included 252 patients diagnosed with lung cancer and 55 (22%) patients subsequently developed BM. The risk of BM was significantly higher in younger patients (p < .0007). The multivariable Cox model did not show a significant association between statin use and BM from lung cancer (Hazard-Ratio (HR) = 1.20, 95% confidence interval (CI): 0.68-2.13). Future studies should focus on late stage NSCLC and examine the incidence of BM among statin users at the time of death.

Lovastatin inhibits VEGFR and AKT activation: synergistic cytotoxicity in combination with VEGFR inhibitors

Background

In a recent study, we demonstrated the ability of lovastatin, a potent inhibitor of mevalonate synthesis, to inhibit the function of the epidermal growth factor receptor (EGFR). Lovastatin attenuated ligand-induced receptor activation and downstream signaling through the PI3K/AKT pathway. Combining lovastatin with gefitinib, a potent EGFR inhibitor, induced synergistic cytotoxicity in a variety of tumor derived cell lines. The vascular endothelial growth factor receptor (VEGFR) and EGFR share similar activation, internalization and downstream signaling characteristics.

Methodology/Principal Findings

The VEGFRs, particularly VEGFR-2 (KDR, Flt-1), play important roles in regulating tumor angiogenesis by promoting endothelial cell proliferation, survival and migration. Certain tumors, such as malignant mesothelioma (MM), also express both the VEGF ligand and VEGFRs that act in an autocrine loop to directly stimulate tumor cell growth and survival. In this study, we have shown that lovastatin inhibits ligand-induced VEGFR-2 activation through inhibition of receptor internalization and also inhibits VEGF activation of AKT in human umbilical vein endothelial cells (HUVEC) and H28 MM cells employing immunofluorescence and Western blotting. Combinations of lovastatin and a VEGFR-2 inhibitor showed more robust AKT inhibition than either agent alone in the H28 MM cell line. Furthermore, combining 5 µM lovastatin treatment, a therapeutically relevant dose, with two different VEGFR-2 inhibitors in HUVEC and the H28 and H2052 mesothelioma derived cell lines demonstrated synergistic cytotoxicity as demonstrated by MTT cell viability and flow cytometric analyses.

Conclusions/Significance

These results highlight a novel mechanism by which lovastatin can regulate VEGFR-2 function and a potential therapeutic approach for MM through combining statins with VEGFR-2 inhibitors.

A clinical review of statins and cancer: helpful or harmful?

The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are the second most prescribed therapeutic drug class in the United States after analgesics. Although these agents are used predominantly to reduce cholesterol concentrations in patients with hyperlipidemia, numerous studies have investigated the pleiotropic effects of statins and their potential in the prevention and/or treatment of other disease states, including cancer. Many theories have been proposed as to how statins may affect the risk or development of malignancies, prompting a clinical review of the literature. Studies have revealed statins to be associated with both increased and decreased cancer risk. Most of the published studies have been observational and retrospective in nature, and most prospective trials evaluated cancer as a secondary end point or adverse event, making it difficult to determine causality. Although most of the available evidence suggests a possible beneficial effect of statins on cancer, further study is needed with better designed trials and/or increased efforts in evaluating cancer as secondary end points in all statin trials until definite conclusions regarding statin effects on cancer risk and occurrence can be made.

Statins can modulate effectiveness of antitumor therapeutic modalities

Despite significant, frequently very strong, antiproliferative and tumoricidal effects of statins demonstrated in vitro, their antitumor effects in animal models are modest, and their efficacy in clinical trials has not been proven. As such, statins seem unlikely to be ever regarded as antitumor agents. However, statins are regularly taken by many elderly cancer patients for the prevention of cardiovascular events. Owing to their pleiotropic effects in normal and tumor cells, statins interact in various ways with many antitumor treatment modalities, either potentiating or diminishing their effectiveness. Elucidation of these interactions might affect the choice of treatment to be planned in cancer patients as some combinations might be contraindicated, whereas others might elicit potentiated antitumor effects but at a cost of increased general toxicity. Some other combinations might induce either comparable or even stronger antitumor effects, but with a beneficial concomitant reduction of specific side effects. Most of the studies reviewed in this article have been carried in vitro or in experimental tumor models, but clinical relevance of the findings is also discussed.

For patients with colorectal cancer, the long-term use of statins is associated with better clinical outcomes

Statins have been found to suppress tumor cell growth and to limit the ability of tumor cells to metastasize in studies involving cell lines and animals. To explore how the long-term use of statins influences the presentation and survival of patients with colorectal cancer (CRC), we conducted a retrospective case-control study of male patients with a new diagnosis of CRC who we categorized as: (1) Statin Users who used statins continuously >/=3 years prior to the diagnosis of CRC and (2) Statin Non-Users who did not use statins. Clinical factors were analyzed by simple Chi-square and multivariate regression analysis to identify independent predictors for advanced CRC. We identified 1,309 male patients with a new diagnosis of CRC (mean age 69 +/- 1.1 (SE) years; 326 Statin Users, 983 Statin Non-Users). Compared to Statin Non-Users, Statin Users had a less advanced tumor stage (2.2 vs. 2.6; P < 0.01), a lower prevalence of metastases (OR = 0.7 [0.4-0.9, 95% CI]; P < 0.01), and a higher frequency of right-sided tumors (OR = 1.6 [1.3-2.1], 95%CI]; P < 0.01). Overall 5-year survival for Statin Users was 37% compared to 33% in Statin Non-Users (OR = 0.7 [0.6-0.9], 95%CI]; P = 0.03). In patients who present to the hospital with CRC, the long-term use of statins is associated with a less advanced tumor stage, a higher prevalence of right-sided tumors, a lower frequency of distant metastases, and a better survival rate.

Simvastatin inhibits induction of matrix metalloproteinase-9 in rat alveolar macrophages exposed to cigarette smoke extract

Matrix metalloproteinase-9 (MMP-9) may play an important role in emphysematous change in chronic obstructive pulmonary disease (COPD), one of the leading causes of mortality and morbidity worldwide. We previously reported that simvastatin, an inhibitor of HMG-CoA reductase, attenuates emphysematous change and MMP-9 induction in the lungs of rats exposed to cigarette smoke. However, it remained uncertain how cigarette smoke induced MMP-9 and how simvastatin inhibited cigarette smoke-induced MMP-9 expression in alveolar macrophages (AMs), a major source of MMP-9 in the lungs of COPD patients. Presently, we examined the related signaling for MMP-9 induction and the inhibitory mechanism of simvastatin on MMP-9 induction in AMs exposed to cigarette smoke extract (CSE). In isolated rat AMs, CSE induced MMP-9 expression and phosphorylation of ERK and Akt. A chemical inhibitor of MEK1/2 or PI3K reduced phosphorylation of ERK or Akt, respectively, and also inhibited CSE-mediated MMP-9 induction. Simvastatin reduced CSE-mediated MMP-9 induction, and simvastatin-mediated inhibition was reversed by farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP). Similar to simvastatin, inhibition of FPP transferase or GGPP transferase suppressed CSE-mediated MMP-9 induction. Simvastatin attenuated CSE-mediated activation of RAS and phosphorylation of ERK, Akt, p65, IkappaB, and nuclear AP-1 or NF-kappaB activity. Taken together, these results suggest that simvastatin may inhibit CSE-mediated MMP-9 induction, primarily by blocking prenylation of RAS in the signaling pathways, in which Raf-MEK-ERK, PI3K/Akt, AP-1, and IkappaB-NF-kappaB are involved.

Statins and breast cancer: may matrix metalloproteinase be the missing link

Statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors), cholesterol-lowering agents widely prescribed for cardiovascular health, have been shown to exert several pleiotropic effects. Although some studies reported that statins have no effects on malignancies of any kind, results of several epidemiologic and in vitro studies highlighted that statins exert anticancer activity in various cell types, showing that long-term therapy inhibits the incidence and/or progression of some human tumours. In particular, in the present overview we focused the attention on a neglected aspect of the pleiotropic functions of some lipophilic statins, suggesting that the possible mechanism of matrix metalloproteinase downregulation arises from prolonged lowering of circulating cholesterol. Our hypothesis may explain the literary findings about the phenomenon of switching of breast cancer phenotypes by statins, shedding the basis of future epidemiologic and basic science studies about the role of circulating and/or tumor-resident cholesterol in the initiation and progression of breast cancer.

Mevastatin reduces cartilage degradation in rabbit experimental osteoarthritis through inhibition of synovial inflammation

OBJECTIVE

To examine the therapeutic efficacy of an HMG-CoA reductase inhibitor (statin) in rabbit osteoarthritis (OA) in vitro and in vivo.

METHODS

In the presence or absence of mevastatin, rabbit chondrocytes and synoviocytes were incubated with Interleukin-1beta (IL-1beta), and analyzed by biochemical methods. Thirty-two mature rabbits that underwent bilateral anterior cruciate ligament transaction (ACLT) received six consecutive weekly intra-articular injections of mevastatin at three different concentrations or a control solution. All animals were sacrificed 6 weeks after ACLT, and the knee joints were assessed by morphological, histological, immunohistochemical, and biochemical methods.

RESULTS

Mevastatin inhibited IL-1beta stimulation of gene expression of monocyte chemoattractant protein-1 (MCP-1) and matrix-metalloproteinases 3 (MMP-3), in synoviocytes but not chondrocytes. The levels of MCP-1 and MMP-3 productions in synoviocytes were significantly reduced by statin-treatment. In rabbit with OA, intra-articular injection of mevastatin significantly reduced cartilage degradation, as assessed by morphological and histological examinations. Synovial tissues of knees treated with mevastatin showed less severe inflammatory responses with reduced thickness of synovial cell lining and less infiltration of subsynovial CD68+monocyte lineage cells compared to untreated control knees. Relative mRNA expressions of MCP-1, IL-1beta, MMP-3, and MMP-13 were reduced in synovial tissues, but not articular cartilage, of knees treated with mevastatin compared with untreated control knees.

CONCLUSION

During the development of experimental OA, intra-articular administration of HMG-CoA reductase inhibitor (statin) reduces inflammatory cell infiltration and matrix-degrading enzyme expression, thus limiting cartilage degradation.

Blockade of the RhoA-JNK-c-Jun-MMP2 cascade by atorvastatin reduces osteosarcoma cell invasion

Osteosarcoma is characterized by a high malignant and metastatic potential, which points to the need for new therapeutic strategies to prevent cell metastasis. In this study, we show that statin-induced HMG-CoA reductase inhibition reduces cell migration and invasion in human and murine osteosarcoma cells, independently of the genotype. The statin-induced reduction of cell migration and invasion was independent of induction of apoptosis and was geranylgeranylpyrophosphate-dependent. The statin reduced matrix metalloproteinase (MMP) 2, 9, and 14 and TIMP2 expression or activity in invading cells. Forced expression of MMP2 and MMP14 overcame the inhibitory effect of the statin on cell invasion, suggesting a role for these MMPs in invasive potential. We also investigated the mechanisms involved in the reduced MMP2 activity and cell invasion. Inhibition of JNK, but not ERK1/2 signaling, reduced MMP2 activity. Pharmacological or constitutive activation of JNK overcame the reduced MMP2 activity and cell invasion induced by the statin. The statin decreased JNK phosphorylation and c-Jun nuclear translocation, suggesting that HMG-CoA reductase inhibition targets the JNK-c-Jun signaling pathway. We showed that mevalonate or geranylgeranylpyrophosphate treatment prevented the statin-induced reduction in JNK phosphorylation, MMP2 activity, and cell invasion. Forced expression of a constitutively active form of RhoA increased JNK phosphorylation and overcame the inhibitory effect of atorvastatin on MMP2 activity and cell invasion. The data establish a link between RhoA, JNK, c-Jun, and MMP2 activity that is functionally involved in the reduction in osteosarcoma cell invasion by the statin. This suggests a novel strategy targeting RhoA-JNK-c-Jun signaling to reduce osteosarcoma cell tumorigenesis.

Determinants of sensitivity to lovastatin-induced apoptosis in multiple myeloma

Statins, commonly used to treat hypercholesterolemia, have been shown to trigger tumor-specific apoptosis in certain cancers, including multiple myeloma (MM), a plasma cell malignancy with poor prognosis. In this article, we show that of a panel of 17 genetically distinct MM cell lines, half were sensitive to statin-induced apoptosis and, despite pharmacodynamic evidence of drug uptake and activity, the remainder were insensitive. Sensitive cells were rescued from lovastatin-induced apoptosis by mevalonate, geranylgeranyl PPi, and partially by farnesyl PPi, highlighting the importance of isoprenylation. Expression profiling revealed that Rho GTPase mRNAs were differentially expressed upon lovastatin exposure in sensitive cells, yet ectopic expression of constitutively active Rho or Ras proteins was insufficient to alter sensitivity to lovastatin-induced apoptosis. This suggests that sensitivity involves more than one isoprenylated protein and that statins trigger apoptosis by blocking many signaling cascades, directly or indirectly deregulated by the oncogenic lesions of the tumor cell. Indeed, clustering on the basis of genetic abnormalities was shown to be significantly associated with sensitivity (P = 0.003). These results suggest that statins may be a useful molecular targeted therapy in the treatment of a subset of MM.

The role of statins in cancer therapy

Administration of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, to ambulatory patients is associated with a lower incidence of long-term adverse cardiovascular events, including death, myocardial infarction, stroke, atrial fibrillation, and renal dysfunction. However, increasing clinical evidence suggests that statins, independent of their effects on serum cholesterol levels, may also play a potential role in the prevention and treatment of cancer. Specifically, statins have been shown to exert several beneficial antineoplastic properties, including decreased tumor growth, angiogenesis, and metastasis. The feasibility and efficacy of statins for the prevention and treatment of cancer is reviewed.

Rho/ROCK pathway as a target of tumor therapy

This study emphasizes the importance of Rho/ROCK pathway in lovastatin-induced apoptosis as replenishment with exogenous isoprenoid, geranylgeranylpyrophosphate (GGPP), resulted in inhibition of apoptosis in cultured tumor cells. Treatment of C6 glioma cells with Toxin B and exoenzyme C3 resulted in cell death suggesting the role of geranylgeranylated protein(s) in the survival of glioma cells. Relative apoptotic death observed in cells transfected with dominant negative constructs of RhoA, Rac, and cdc42 imply Rho A as playing the major role in cell survival. Furthermore, the inhibition of Rho A kinase (ROCK), a direct downstream effector of Rho A, by Y-27632 or dominant negative of ROCK, induced apoptosis in glioma cells. These findings indicate that RhoA/ROCK pathway is involved negatively in the regulation of glioma cell death pathway. Moreover, in vivo studies of lovastatin treatment in animals implanted with C6 glioma cell tumors also resulted in smaller tumor size and induced apoptosis in the tumor tissue. The implantation of stably transfected C6 glioma cells with expression vector of C3 exoenzyme, dominant negative of RhoA and ROCK, resulted in significant smaller tumor mass, further establishing the importance of geranylgeranylated proteins, specifically RhoA and its downstream effecter ROCK, in cell survival and tumor genesis.

Pharmacokinetics of a Lidocaine Patch 5% in Dogs

Lidocaine is increasingly used in transdermal drug delivery systems for different pain conditions in human medicine whereby several pharmacokinetic studies have demonstrated minimal systemic absorption in men. In the present study, the pharmacokinetics of a lidocaine patch 5% was studied in six dogs. In the first experiment, one single lidocaine patch was applied for 12 h to the lateral side of the thorax after removing the hair either by clipping or by the application of a depilatory agent, according to a two-way crossover design. No potential adverse effects induced by the patches were observed in either group. In dogs with clipped hair, a mean peak plasma lidocaine concentration of 62.94 ng/ml was obtained after 10.67 h. In the depilatory group, a mean peak plasma concentration of 103.55 ng/ml was reached after 9.27 h. Significant differences in the AUC(0 --> infinity), C(max), k(a) and T(1/2a) were noticed between the two groups. No significant differences were found for the elimination parameters and for T(max). In the second experiment, the patches were applied for 60 h to the clipped skin in order to study the absorption kinetics after a prolonged application period. There, the mean peak lidocaine plasma concentration was 45.18 ng/ml achieved after 24 h and a final concentration of 29.37 ng/ml was obtained at 60 h. In conclusion, all dogs tolerated the transdermal lidocaine patch well. The results of this study suggest that there is an overall minimal absorption from the lidocaine patch. However, the application of a depilatory agent leads to a more rapid and increased absorption of lidocaine.

Anti-angiogenic and anti-inflammatory effects of statins: relevance to anti-cancer therapy

Angiogenesis is indispensable for the growth of solid tumors and angiogenic factors are also involved in the progression of hematological malignancies. Targeting the formation of blood vessels is therefore regarded as a promising strategy in cancer therapy. Interestingly, besides demonstration of some beneficial effects of novel anti-angiogenic compounds, recent data on the activity of already available drugs point to their potential application in anti-angiogenic therapy. Among these are the statins, the inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. Statins are very efficient in the treatment of hypercholesterolemia in cardiovascular disorders; however, their effects are pleiotropic and some are not directly related to the inhibition of cholesterol synthesis. Some reports particularly highlight the pro-angiogenic effects of statins, which are caused by low, nanomolar concentrations and are regarded as beneficial for the treatment of cardiovascular diseases. On the other hand, the anti-angiogenic activities, observed at micromolar concentrations of statins, may be of special significance for cancer therapy. Those effects are caused by the inhibition of both proliferation and migration and induction of apoptosis in endothelial cells. Moreover, the statin-mediated inhibition of vascular endothelial growth factor synthesis, the major angiogenic mediator, may contribute to the attenuation of angiogenesis. It has been suggested that the anti-cancer effect of statins can be potentially exploited for the cancer therapy. However, several clinical trials aimed at the inhibition of tumor growth by treatment with very high doses of statins did not provide conclusive data. Herein, the reasons for those outcomes are discussed and the rationale for further studies is presented.

Different anticancer effects of fluvastatin on primary hepatocellular tumors and metastases in rats

Rats (FLF1) were pretreated with 2 and 20 mg/kg/day fluvastatin (Flu), and after 6 weeks, hepatocellular tumor cells were inoculated under the left renal capsule. At different times, growth and pyruvate kinase (PK) activity of the primary tumors and lymph node metastases were determined. Flu had a dose-dependent inhibitory effect on primary and metastatic tumors, and the inhibitory effect on growth and PK activity in metastases were higher than in primary tumors. Finally, Flu had an earlier inhibitory effect on the early appeared PK activity in metastases than in primary tumors.

Treatment with simvastatin suppresses the development of experimental abdominal aortic aneurysms in normal and hypercholesterolemic mice

OBJECTIVE

To determine if treatment with hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) can influence the development of experimental abdominal aortic aneurysms (AAAs).

SUMMARY BACKGROUND DATA

AAAs are associated with atherosclerosis, chronic inflammation, and matrix metalloproteinase (MMP)-mediated connective tissue destruction. Because statins exert antiinflammatory activities independent of their lipid-lowering effects, these agents may help suppress aneurysmal degeneration.

METHODS

C57Bl/6 wild-type and hypercholesterolemic apoE-deficient mice underwent transient perfusion of the aorta with elastase followed by subcutaneous treatment with either 2 mg/kg simvastatin per day or vehicle. Aortic diameter (AD) was measured before and 14 days after elastase perfusion. The extent of aortic dilatation (DeltaAD) was determined with AAAs defined as DeltaAD >100%.

RESULTS

Wild-type mice treated with simvastatin exhibited a 21% reduction in DeltaAD and a 33% reduction in AAAs compared with vehicle-treated controls. Suppression of AAAs in simvastatin-treated mice was associated with preservation of medial elastin and vascular smooth muscle cells, as well as a relative reduction in aortic wall expression of MMP-9 and a relative increase in expression of TIMP-1. In hypercholesterolemic apoE-deficient mice, treatment with simvastatin was associated with a 26% reduction in DeltaAD and a 30% reduction in AAAs. Treatment with simvastatin had no effect on serum cholesterol levels in either normal or hypercholesterolemic mice.

CONCLUSIONS

Treatment with simvastatin suppresses the development of experimental AAAs in both normal and hypercholesterolemic mice. The mechanisms of this effect are independent of lipid-lowering and include preservation of medial elastin and smooth muscle cells, as well as altered aortic wall expression of MMPs and their inhibitors.

Simvastatin inhibits MMP‐9 secretion from human saphenous vein smooth muscle cells by inhibiting the RhoA/ROCK pathway and reducing MMP‐9 mRNA levels

Increased matrix metalloproteinase-9 (MMP-9) expression is associated with intimal hyperplasia in saphenous vein (SV) bypass grafts. Recent evidence suggests that HMG-CoA reductase inhibitors (statins) can prevent the progression of vein graft failure. Here we investigated whether statins inhibited MMP-9 secretion from cultured human SV smooth muscle cells (SMC) and examined the underlying mechanisms. SV-SMC from different patients were exposed to phorbol ester (TPA) or PDGF-BB plus interleukin-1alpha (IL-1). MMP-9 secretion and mRNA expression were analyzed using gelatin zymography and RT-PCR, respectively. Specific signal transduction pathways were investigated by immunoblotting and pharmacological inhibition. Simvastatin reduced TPA- and PDGF/IL-1-induced MMP-9 secretion and mRNA levels, effects reversed by geranylgeranyl pyrophosphate and mimicked by inhibiting Rho geranylgeranylation or Rho-kinase (ROCK). MMP-9 secretion induced by PDGF/IL-1 was mediated via the ERK, p38 MAPK, and NFkappaB pathways, whereas that induced by TPA was mediated specifically via the ERK pathway. Simvastatin failed to inhibit activation of these signaling pathways. Moreover, simvastatin did not affect MMP-9 mRNA stability. Together these data suggest that simvastatin reduces MMP-9 secretion from human SV-SMC by inhibiting the RhoA/ROCK pathway and decreasing MMP-9 mRNA levels independently of effects on signaling pathways required for MMP-9 gene expression.

Carnosol inhibits the invasion of B16/F10 mouse melanoma cells by suppressing metalloproteinase-9 through down-regulating nuclear factor-kappaB and c-Jun

Carnosol, a constant constituent of Rosmarinus officinalis extracts, is a phenolic diterpene shown to have antioxidant and anticarcinogen properties. In our studies, carnosol inhibited the invasion of highly metastatic mouse melanoma B16/F10 cells in vitro. First, the antimetastatic potentials of carnosol were examined by soft agar colony formation assay. Second, carnosol dose-dependently inhibited B16/F10 cell migration and invasion by in vitro transwell assay. Third, the decreasing activity of metalloproteinase was observed by zymographic assay. The result revealed that the treatment of carnosol could diminish the activity of MMP-9 more than MMP-2. Next, we analyzed the amounts of MMP-9 and MMP-2 proteins in the cells. The data indicated MMP-9 protein was also suppressed by carnosol in the same manner. In accordance with the above data, the results of reverse transcriptase polymerase chain reaction (RT-PCR) analysis showed a reduced level of MMP-9 mRNA. Furthermore, carnosol significantly inhibited the tyrosine phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, AKT, p38, JNK and inhibition of activation of transcription factors NFkappa-B and c-Jun. These results lead us to conclude that carnosol could restrict the invasive ability of B16/F10 mouse melanoma cells by reducing MMP-9 expression and activity through suppressing (ERK) 1/2, AKT, p38, and JNK signaling pathway and inhibition of NF-kappaB and AP-1 binding activity. Taken together, these results indicate that carnosol targets MMP-mediated cellular events in cancer cells and provides a new mechanism for its anticancer activity.

Studies of the isoprenoid-mediated inhibition of mevalonate synthesis applied to cancer chemotherapy and chemoprevention

Pools of farnesyl diphosphate and other phosphorylated products of the mevalonate pathway are essential to the post-translational processing and physiological function of small G proteins, nuclear lamins, and growth factor receptors. Inhibitors of enzyme activities providing those pools, namely, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase and mevalonic acid-pyrophosphate decarboxylase, and of activities requiring substrates from the pools, the prenyl protein transferases, have potential for development as novel chemotherapeutic agents. Their potentials as suggested by the clinical responses recorded in Phase I and II investigations of inhibitors of HMG CoA reductase (the statins), of mevalonic acid-pyrophosphate decarboxylase (sodium phenylacetate and sodium phenylbutyrate), and of farnesyl protein transferase (R115777, SCH66336, BMS-214662, Tipifarnib, L-778,123, and, prematurely, perillyl alcohol) are dimmed by dose-limiting toxicities. These nondiscriminant growth-suppressive agents induce G1 arrest and initiate apoptosis and differentiation, effects attributed to modulation of cell signaling pathways either by modulating gene expression, suppressing the post-translational processing of signaling proteins and growth factor receptors, or altering diacylglycerol signaling. Diverse isoprenoids and the HMG CoA reductase inhibitor, lovastatin, modulate cell growth, induce cell cycle arrest, initiate apoptosis, and suppress cellular signaling activities. Perillyl alcohol, the isoprenoid of greatest clinical interest, initially was considered to inhibit farnesyl protein transferase; follow-up studies revealed that perillyl alcohol suppresses the synthesis of small G proteins and HMG CoA reductase. In sterologenic tissues, sterol feedback control, mediated by sterol regulatory element binding proteins (SREBPs) 1a and 2, exerts the primary regulation on HMG CoA reductase activity at the transcriptional level. Secondary regulation, a nonsterol isoprenoid-mediated fine-tuning of reductase activity, occurs at the levels of reductase translation and degradation. HMG CoA reductase activity in tumors is elevated and resistant to sterol feedback regulation, possibly as a consequence of aberrant SREBP activities. Nonetheless, tumor reductase remains sensitive to isoprenoid-mediated post-transcriptional downregulation. Farnesol, an acyclic sesquiterpene, and farnesyl homologs, gamma-tocotrienol and various farnesyl derivatives, inhibit reductase synthesis and accelerate reductase degradation. Cyclic monoterpenes, d-limonene, menthol and perillyl alcohol and beta-ionone, a carotenoid fragment, lower reductase mass; perillyl alcohol and d-limonene lower reductase mass by modulating translational efficiency. The elevated reductase expression and greater demand for nonsterol products to maintain growth amplify the susceptibility of tumor reductase to isoprenoids, therein rendering tumor cells more responsive than normal cells to isoprenoid-mediated growth suppression. Blends of lovastatin, a potent nondiscriminant inhibitor of HMG CoA reductase, and gamma-tocotrienol, a potent isoprenoid shown to post-transcription-ally attenuate reductase activity with specificity for tumors, synergistically affect the growth of human DU145 and LNCaP prostate carcinoma cells and pending extensive preclinical evaluation, potentially offer a novel chemotherapeutic strategy free of the dose-limiting toxicity associated with high-dose lovastatin and other nondiscriminant mevalonate pathway inhibitors.

Invasion of normal human fibroblasts induced by v-Fos is independent of proliferation, immortalization, and the tumor suppressors p16INK4a and p53

Invasion is generally perceived to be a late event during the progression of human cancer, but to date there are no consistent reports of alterations specifically associated with malignant conversion. We provide evidence that the v-Fos oncogene induces changes in gene expression that render noninvasive normal human diploid fibroblasts highly invasive, without inducing changes in growth factor requirements or anchorage dependence for proliferation. Furthermore, v-Fos-stimulated invasion is independent of the pRb/p16(INK4a) and p53 tumor suppressor pathways and telomerase. We have performed microarray analysis using Affymetrix GeneChips, and the gene expression profile of v-Fos transformed cells supports its role in the regulation of invasion, independent from proliferation. We also demonstrate that invasion, but not proliferation, is dependent on the activity of the up-regulated epidermal growth factor receptor. Taken together, these results indicate that AP-1-directed invasion could precede deregulated proliferation during tumorigenesis and that sustained activation of AP-1 could be the epigenetic event required for conversion of a benign tumor into a malignant one, thereby explaining why many malignant human tumors present without an obvious premalignant hyperproliferative dysplastic lesion.

Lovastatin inhibits Rho-regulated expression of E-selectin by TNFalpha and attenuates tumor cell adhesion

E-selectin mediated cell-cell adhesion plays an important role in inflammatory processes and extravasation of tumor cells. Tumor necrosis factor-alpha (TNF-alpha) induces E-selectin gene and protein expression in primary human endothelial cells (HUVEC) and in an endothelial cell line (EA.hy-926). As shown by ELISA and FACS analyses, HMG-CoA reductase inhibitors (e.g., lovastatin) impair the TNF-alpha stimulated increase in E-selectin protein expression. Similar results were obtained for E-selectin mRNA expression and promoter activity, indicating that the effect of lovastatin is based on inhibition of gene expression. The effective inhibitory concentration of lovastatin was in a physiologically relevant range (IC50<0.1 microM). Lovastatin-mediated block of TNF-alpha induced E-selectin expression is due to inhibition of protein geranylgeranylation rather than farnesylation. Down-regulation of Rho signaling by coexpression of dominant-negative Rho mutants (i.e RhoA, RhoB and Rac) impaired TNF-alpha driven E-selectin gene expression, indicating Rho signaling to be essential for transcriptional activation of the E-selectin gene. Inhibition of E-selectin expression by lovastatin gives rise to a significant reduction in TNF-alpha stimulated adhesion of colon carcinoma cells to HUVEC. Furthermore, low concentration of lovastatin (i.e., < or =1 microM) attenuated TNF-alpha induced tumor cell invasion in vitro. The data support the view that statins might be clinically useful in protection against E-selectin mediated metastasis.

Inhibition of pancreatic stellate cell activation by the hydroxymethylglutaryl coenzyme A reductase inhibitor lovastatin

Pancreatic stellate cells (PSCs) play a key role in pancreatic fibrosis, a constant feature of chronic pancreatitis. PSC activation occurs in response to profibrogenic mediators such as cytokines and involves proliferation, transition towards a myofibroblastic phenotype and enhanced production of extracellular matrix proteins. Previously, we have shown that PSC activation correlates with the activity of the Ras-Raf-ERK (extracellular signal-regulated kinase) signalling cascade [Gut 51 (2002) 579]. Using a rat culture model of PSCs, we have now evaluated the effects of lovastatin, a hydroxymethylglutaryl coenzyme A reductase inhibitor that interferes with protein isoprenylation, on PSC viability and activation as well as on signalling through Ras proteins. Apoptotic cells were detected applying the TUNEL assay. Proliferation of PSCs was quantitated using the bromodeoxyuridine DNA incorporation assay. Expression of alpha-smooth muscle actin (an indicator of the myofibroblastic phenotype), ERK activation and membrane translocation of the Ras superfamily member RhoA were analysed by immunoblotting. Lovastatin inhibited serum- and platelet-derived growth factor-stimulated PSC proliferation in a dose-dependent manner. At drug concentrations above the level required for growth inhibition, a strong increase of apoptotic cells was observed. Furthermore, lovastatin inhibited induction of alpha-smooth muscle actin expression in the course of primary culture. Immunoblot experiments indicated that lovastatin suppressed both Ras-mediated ERK 1/2 activation and platelet-derived growth factor-induced membrane translocation of RhoA. Together, our data suggest that lovastatin, through the interruption of Ras signalling, interferes with PSC activation. The antifibrotic efficiency of statins should be tested in animal models of chronic pancreatitis.

Penta-O-galloyl-beta-D-glucose inhibits the invasion of mouse melanoma by suppressing metalloproteinase-9 through down-regulation of activator protein-1

Penta-O-galloyl-beta-D-glucose (5GG) inhibited the invasion of highly metastatic mouse melanoma B16F10 cells in vitro, as demonstrated by transwell assay. Its ability to diminish the activity of matrix metalloproteinase (MMP) was demonstrated by zymographic assay. Our data showed 5GG could diminish the activity of MMP-9 more than that of MMP-2. The effect on MMP-9 was elicited in a dose- and time-dependent manner, with IC50 of 15 microM. Next, we analyzed the amounts of MMP-9 and MMP-2 protein in conditioned media and in the cells. The data indicated MMP-9 proteins were also suppressed by 5GG in the same manner. In accordance with these data above, the results of reverse transcriptase polymerase chain reaction (RT-PCR) and Northern blot analysis showed a reduced level of MMP-9 mRNA. Furthermore, we studied transcription factor binding to MMP-2 and MMP-9 promoter regions by electrophoretic mobility shift assay (EMSA) in the nucleus. The results suggested that the transcription factor binding activities of Activator protein-1 (AP-1) and Sp-1 sites was mainly down-regulated by 5GG in the concentration range of 5-15 microM, but not that of nuclear factor kappaB (NF-kappaB), polioma enhancer activator 3 (PEA-3), and Activator protein-2 (AP-2) sites. The Western blot analysis of AP-1 nuclear protein showed a reduced level of c-Jun but not of c-Fos. In addition, the expression of Sp-1 and c-Jun protein was also suppressed. To elucidate whether the transcriptional activity of AP-1 or Sp-1 sites is more important, we transfected MMP-9/luciferase reporter vector, under MMP-9 promoter control, into the cells. We found that a decreased transcriptional activity of AP-1 sites is sufficient to reduce MMP-9 promoter activity. These results lead us to conclude that 5GG restricts the invasive ability of B16F10 mouse melanoma cells by reducing MMP-9 activity, by suppressing the transcriptional activity of AP-1 sites and the expression of c-Jun protein. The result may provide a potential mechanism for 5GG in cancer chemopreventive action.

Antagonistic and agonistic effects of quinazoline tyrosine kinase inhibitors on mutant EGF receptor function

A mutated form of the EGF receptor (EGFRvIII), resulting from deletion of exons 2-7, is an oncogenic protein that is expressed in multiple human tumors. This mutation induces ligand-independent activation of the EGFR tyrosine kinase and thereby can initiate unregulated cell growth and tumorigenesis. Thus, inhibition of the kinase activity of EGFRvIII is a potential means of suppressing its oncogenic properties. Certain tyrosine kinase inhibitors (tyrphostins) specifically inhibit the wild-type EGFR and thereby inhibit tumor growth both in vitro and in vivo. We demonstrate that the quinazoline tyrphostins AG 1478 and AG 1517 can suppress morphologic transformation of cell lines by EGFRvIII. Quinazolines were found to inhibit receptor autophosphorylation and signaling through MAP kinase, but had minimal effects on association of EGFRvIII with Grb2/SOS. Low concentrations of quinazoline also increased receptor dimerization and phosphotyrosine content. This was associated with increases in colony formation in soft agar and increased invasion through matrigel for AG 1478. Thus, both AG 1478 and AG 1517 can inhibit multiple EGFRvIII signaling pathways, but at low concentrations AG 1478 can enhance colony formation, presumably related to augmented homodimerization of the receptor and activation of downstream signaling.

Recent advances in pharmacotherapy for cancer pain management

PURPOSE

This review provides an outline of several recent advances in drug treatment options and strategies for managing cancer pain.

OVERVIEW

The development of cyclooxygenase-2-selective nonsteroidal anti-inflammatory drugs (NSAIDs) and transmucosal fentanyl citrate provide new pharmacologic options for the treatment of cancer pain. Combinations of opioid agonists and antagonists have provided data on new strategies to balance effective analgesia with analgesic-related adverse effects. In addition, the spectrum of adjuvant agents for the treatment of neuropathic pain has been extended to various antidepressants and topical analgesics. There is continued research on the role of the N-methyl-d-aspartate (NMDA) receptor and, specifically, on NMDA receptor antagonists that may augment analgesia and combat opioid resistance. Finally, a more potent generation of bisphosphonates may lead to improved pain relief for patients with bone metastases.

CLINICAL IMPLICATIONS

With a combination of emerging new clinical research and professional practice experience of the cancer care team, new strategies will continue to be developed and implemented, resulting in the continued improved care of patients with cancer.

Simvastatin preserves the structure of coronary adventitial vasa vasorum in experimental hypercholesterolemia independent of lipid lowering

BACKGROUND

Previous studies have demonstrated that experimental hypercholesterolemia leads to neovascularization in the coronary artery vasa vasorum (VV). Recent evidence suggests that HMG-CoA reductase inhibitors (statins) have beneficial effects independent of lipid lowering. We aimed to determine the effect of simvastatin on coronary VV neovascularization, in the absence of cholesterol lowering.

METHODS AND RESULTS

Pigs were randomized to 3 groups fed a normal (N), high cholesterol (HC), or HC+simvastatin (HC+S) diet for 12 weeks. The proximal left anterior descending artery was isolated, scanned with micro-CT, and reconstructed. Quantification of the VV density in serial cross-sections along the vessel was then performed. LDL cholesterol was similarly increased in HC and HC+S compared with N. There was an increase in both VV density (4.7+/-0.3 versus 2.7+/-0.2 n/mm(2); P<0.05) and vessel wall area (3.1+/-0.2 versus 1.8+/-0.1 mm(2); P<0.05) in HC compared with N. The VV density in HC+S was preserved compared with HC (3.0+/-0.2 n/mm(2); P<0.05), despite similar increase in vessel wall area compared with N (2.5+/-0.1 mm(2); P<0.05). Coronary artery tissue expression of VEGF was increased in HC but not in HC+S compared with N. In parallel, immunoreactivity for HIF-1alpha, VEGF, MMP-2, and MMP-9 was accentuated in the outer media in HC but not in HC+S compared with N.

CONCLUSIONS

This study demonstrates that simvastatin attenuates hypoxia in the coronary artery wall and VV neovascularization in experimental hypercholesterolemia, despite no change in plasma lipids. These data are consistent with an additional mechanism for the vascular effects of the statins, independent of cholesterol lowering.