Pleiotropic effects of statins via interaction with the lipid bilayer: A combined approach

Effect of Statin Lipophilicity on the Proliferation of Hepatocellular Carcinoma Cells

The HMG-CoA reductase inhibitors, statins, are drugs used globally for lowering the level of cholesterol in the blood. Different clinical studies of statins in cancer patients have indicated a decrease in cancer mortality, particularly in patients using lipophilic statins compared to those on hydrophilic statins. In this paper, we selected two structurally different statins (simvastatin and pravastatin) with different lipophilicities and investigated their effects on the proliferation and apoptosis of hepatocellular carcinoma cells. Lipophilic simvastatin highly influences cancer cell growth and survival in a time- and concentration-dependent manner, while pravastatin, due to its hydrophilic structure and limited cellular uptake, showed minimal cytotoxic effects.

Insight into the effect of ibuprofen on the permeability of the membrane: a molecular dynamic simulation study

Studying interactions between drugs and cell membranes is of great interest to designing novel drugs, optimizing drug delivery, and discerning drug mechanism action. In this study, we investigated the physical properties of the bilayer membrane model of POPC upon interaction with ibuprofen (IBU) using molecular dynamics simulations. The area per lipid (APL) was calculated to describe the effect of ibuprofen on the packing properties of the lipid bilayer. The APL was 0.58 nm2 and 0.63 nm2 for the membrane in low and high IBU respectively, and 0.57 nm2 for the membrane without IBU. Our finding showed that the mean square deviation (MSD) increased with increased ibuprofen content. In addition, the order parameter for the hydrocarbon chain of lipids increased with increased ibuprofen content. There was an increment in the transfer free energy after the head group region while it was maximum in the hydrophobic core for hydrogen peroxide (H2O2) (∼6.2 kcal.mol-1) and H2O (∼3.4 kcal.mol-1) which then decreased to respective values of (∼4.6 kcal.mol-1), and (∼2.3 kcal.mol-1) at the center of the bilayer in the presence of IBU. It seems that in the presence of ibuprofen, the free energy profile of the permeability of water and H2O2 significantly decreased. These findings show that ibuprofen significantly influences the physical properties of the bilayer by decreasing the packing and intermolecular interaction in the hydrocarbon chain region and increasing the water permeability of the bilayer. These results may provide insights into the local cytotoxic side effects of ibuprofen and its underlying molecular mechanisms.Communicated by Ramaswamy H. Sarma.

Association between statins exposure and risk of skin cancer: an updated meta-analysis

This study aimed to investigate the relationship between statin (lipophilic statin and hydrophilic statin) exposure and the risk of skin cancer. The incidence of skin cancer under statin exposure was used as the primary outcome, and the relevant studies were screened from Web of Science, PubMed, Cochrane Library, and EBSCO electronic database until September 2022. Ten observational studies and two randomized controlled trials (RCTs) were included. The statistical results indicated that in lipophilic statins, the exposed group had a higher risk of skin cancer than the non-exposed group (OR: 1.09, P = 0.003). However, compared with the non-exposed group, there was no significant difference between hydrophilic statins exposure and the incidence of skin cancer (OR: 1.02, P = 0.341). Further subgroup analysis of the subtypes of statins revealed that compared with the non-exposed group, exposure to lovastatin (OR: 1.18, P = 0.048) or simvastatin (OR: 1.11, P < 0.001) was a risk factor for skin cancer. Besides, subgroup analysis based on the subtypes of skin cancer demonstrated that the risks of melanoma (OR: 1.13, P = 0.009), basal cell carcinoma (BCC) (OR: 1.05, P = 0.036), and squamous cell carcinoma (SCC) (OR: 1.13, P = 0.026) under lipophilic statin exposure were significantly higher than those in the non-exposed group. On the contrary, compared with the non-exposed group, the risk of BCC was significantly reduced under the exposure of hydrophilic statins (OR: 0.93, P = 0.031). This study showed that the relationship between statin exposure and skin cancer risk was affected by the subtypes of statins and skin cancer subtypes.

Model Lipid Raft Membranes for Embedding Integral Membrane Proteins: Reconstitution of HMG-CoA Reductase and Its Inhibition by Statins

For the first time, HMG-CoA reductase, the membrane protein responsible for cholesterol synthesis, was incorporated into a lipid membrane consisting of DOPC:Chol:SM at a 1:1:1 molar ratio, which mimics the lipid rafts of cell membranes. The membrane containing the protein was generated in the form of either a proteoliposomes or a film obtained by spreading the proteoliposomes at the air-water interface to prepare a protein-rich and stable lipid layer over time. The lipid vesicle parameters were characterized using dynamic light scattering (DLS) and fluorescence microscopy. The incorporation of HMG-CoA reductase was reflected in the increased size of the proteoliposomes compared to that of the empty liposomes of model rafts. Enzyme reconstitution was confirmed by measuring the activity of NADPH, which participates in the catalytic process. The thin lipid raft films formed by spreading liposomes and proteoliposomes at the air-water interface were investigated using the Langmuir technique. The activities of the HMG-CoA reductase films were preserved over time, and the two lipid raft systems, nanoparticles and films, were exposed to solutions of fluvastatin, a HMG-CoA reductase inhibitor commonly used in the treatment of hypercholesterolemia. Both lipid raft systems constructed were useful membrane models for the determination of reductase activity and for monitoring the statin inhibitory effects and may be used for investigating other integral membrane proteins during exposure to inhibitors/activators considered to be potential drugs.

Comparison of the Treatment Efficacy of Rosuvastatin versus Atorvastatin Loading Prior to Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction

The aim of this study was to compare the effect of a single high-dose rosuvastatin versus atorvastatin preloading in ST-elevation myocardial infarction (STEMI) patients receiving primary percutaneous coronary intervention (PCI.) Methods: A total of 99 patients presented with STEMI and were randomly divided into three groups—a control group (n = 33) with no statin treatment, an atorvastatin group (n = 33) with a single 80 mg atorvastatin dose and the rosuvastatin group (n = 33) with a single 40 mg rosuvastatin dose in the emergency room (ER) prior to PCI. Post-interventional thrombolysis in myocardial infarction (TIMI) flow grade and corrected TIMI frame count (CTFC) were recorded, and ST-segment resolution was measured. Results: CTFC was significantly lower for the atorvastatin group (p-value < 0.01) than in the control group. A final TIMI flow grade 3 was achieved in 32 (97.0%) patients in the rosuvastatin group and 28 (84.8%) patients in the atorvastatin group compared with only 25 (75.8%) patients in the control group (p = 0.014). Peak CK-MB in the rosuvastatin group (263.2 [207.2−315.6]) and the atorvastatin group (208 [151.0−314.1]) was lower compared to that in the control group (398.4 [303.9−459.3]); p < 0.001. Conclusions: A single extensive dose of lipophilic atorvastatin prior to primary PCI in STEMI patients showed better improvement in microvascular myocardial perfusion compared to hydrophilic rosuvastatin.

Lipidomic and Membrane Mechanical Signatures in Triple-Negative Breast Cancer: Scope for Membrane-Based Theranostics

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer associated with poor prognosis, higher grade, and a high rate of metastatic occurrence. Limited therapeutic interventions and the compounding issue of drug resistance in triple-negative breast cancer warrants the discovery of novel therapeutic targets and diagnostic modules. To this view, in addition to proteins, lipids also regulate cellular functions via the formation of membranes that modulate membrane protein function, diffusion, and their localization; thus, orchestrating signaling hot spots enriched in specific lipids/proteins on cell membranes. Lipid deregulation in cancer leads to reprogramming of the membrane dynamics and functions impacting cell proliferation, metabolism, and metastasis, providing exciting starting points for developing lipid-based approaches for treating TNBC. In this review, we provide a detailed account of specific lipidic changes in breast cancer, link the altered lipidome with membrane structure and mechanical properties, and describe how these are linked to subsequent downstream functions implicit in cancer progression, metastasis, and chemoresistance. At the fundamental level, we discuss how the lipid-centric findings in TNBC are providing cues for developing lipid-inspired theranostic strategies while bridging existing gaps in our understanding of the functional involvement of lipid membranes in cancer.

Membrane Cholesterol Content and Lipid Organization Influence Melittin and Pneumolysin Pore-Forming Activity

Melittin, the main toxic component in the venom of the European honeybee, interacts with natural and artificial membranes due to its amphiphilic properties. Rather than interacting with a specific receptor, melittin interacts with the lipid components, disrupting the lipid bilayer and inducing ion leakage and osmotic shock. This mechanism of action is shared with pneumolysin and other members of the cholesterol-dependent cytolysin family. In this manuscript, we investigated the inverse correlation for cholesterol dependency of these two toxins. While pneumolysin-induced damage is reduced by pretreatment with the cholesterol-depleting agent methyl-β-cyclodextrin, the toxicity of melittin, after cholesterol depletion, increased. A similar response was also observed after a short incubation with lipophilic simvastatin, which alters membrane lipid organization and structure, clustering lipid rafts. Therefore, changes in toxin sensitivity can be achieved in cells by depleting cholesterol or changing the lipid bilayer organization.

Statins enhance the chemosensitivity of R-CHOP in diffuse large B-cell lymphoma

The beneficial effect of statins on the anti-lymphoma activity of the rituximab-based chemotherapy regimen is controversial. Here, we retrospectively reviewed patients with naïve-treated advanced diffuse large B-cell lymphoma (DLBCL) receiving frontline R-CHOP, and for whom data regarding differential statins use was available at the time of initiation of treatment. We observe that patients treated with statins and R-CHOP experienced a significantly higher CR rate as compared to those who received R-CHOP only. We further show that patients receiving medium or high intensity statins and R-CHOP experienced a significantly higher CR as compared to those treated with R-CHOP. Six-year progression free survival was higher for patients who received medium or higher intensity statins as compared to low or no statins. The potential contribution of cholesterol pathway in doxorubicin sensitivity was supported by in vitro/in vivo studies. Our study suggests that targeting cholesterol-using lovastatin could be a therapeutic strategy to enhance responses to R-CHOP in DLBCL patients.

Spectrally and Time-Resolved Fluorescence Imaging of 22-NBD-Cholesterol in Human Peripheral Blood Mononuclear Cells in Chronic Kidney Disease Patients

The interaction of the fluorescent probe 22-NBD-cholesterol with membranes of human peripheral blood mononuclear cells (PBMC) was tested by time- and spectrally resolved fluorescence imaging to monitor the disturbance of lipid metabolism in chronic kidney disease (CKD) and its treatment with statins. Blood samples from healthy volunteers (HV) and CKD patients, either treated or untreated with statins, were compared. Spectral imaging was done using confocal microscopy at 16 spectral channels in response to 458 nm excitation. Time-resolved imaging was achieved by time-correlated single photon counting (TCSPC) following excitation at 475 nm. The fluorescence of 22-NBD-cholesterol was mostly integrated into plasmatic membrane and/or intracellular membrane but was missing from the nuclear region. The presence of two distinct spectral forms of 22-NBD-cholesterol was uncovered, with significant variations between studied groups. In addition, two fluorescence lifetime components were unmasked, changing in CKD patients treated with statins. The gathered results indicate that 22-NBD-cholesterol may serve as a tool to study changes in the lipid metabolism of patients with CKD to monitor the effect of statin treatment.

Interaction of the pitavastatin with model membranes

Pitavastatin is a statin drug that, by competitively inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A reductase, can lower serum cholesterol levels of low-density lipoprotein (LDL) accompanied by side effects due to pleiotropic effects leading to statin intolerance. These effects can be explained by the lipophilicity of statins, which creates membrane affinity and causes statin localization in cellular membranes. In the current report, the interaction of pitavastatin with POPC model membranes and its influence on the membrane structure were investigated using H, H and P solid-state NMR spectroscopy. Our experiments show the average localization of pitavastatin at the lipid/water interface of the membrane, which is biased towards the hydrocarbon core in comparison to other statin molecules. The membrane binding of pitavastatin also introduced an isotropic component into the ³¹P NMR powder spectra, suggesting that some of the lamellar POPC molecules are converted into highly curved structures.

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Solid-state NMR spectroscopy shows pitavastatin effect on the bilayer

•Pitavastatin lowers the POPC order parameters

•Pitavastatin localize in the upper chain of the POPC bilayer

•Isotropic membrane phases are observed in the presence of pitavastatin

Modulation of Phospholipid Bilayer Properties by Simvastatin

Simvastatin (Zocor) is one of the most prescribed drugs for reducing high cholesterol. Although simvastatin is ingested in its inactive lactone form, it is converted to its active dihydroxyheptanoate form by carboxylesterases in the liver. The dihydroxyheptanoate form can also be converted back to its original lactone form. Unfortunately, some of the side effects associated with the intake of simvastatin and other lipophilic statins at higher doses include statin-associated myopathy (SAM) and, in more severe cases, kidney failure. While the cause of SAM is unknown, it is hypothesized that these side effects are dependent on the localization of statins in lipid bilayers and their impact on bilayer properties. In this work, we carry out all-atom molecular dynamics simulations on both the lactone and dihydroxyheptanoate forms of simvastatin (termed "SN" and "SA", respectively) with a pure 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayer and a POPC/cholesterol (30 mol %) binary mixture as membrane models. Additional simulations were carried out with multiple simvastatin molecules to mimic in vitro conditions that produced pleiotropic effects. Both SN and SA spontaneously diffused into the lipid bilayer, and a longer simulation time of 4 μs was needed for the complete incorporation of multiple SAs into the bilayer. By constructing potential mean force and electron density profiles, we find that SN localizes deeper within the hydrophobic interior of the bilayer and that SA has a greater tendency to form hydrogen-bonding interactions with neighboring water molecules and lipid headgroups. For the pure POPC bilayer, both SN and SA increase membrane order, while membrane fluidity increases for the POPC/cholesterol bilayer.

Why Do Tethered-Bilayer Lipid Membranes Suit for Functional Membrane Protein Reincorporation?

Membrane proteins (MPs) are essential for cellular functions. Understanding the functions of MPs is crucial as they constitute an important class of drug targets. However, MPs are a challenging class of biomolecules to analyze because they cannot be studied outside their native environment. Their structure, function and activity are highly dependent on the local lipid environment, and these properties are compromised when the protein does not reside in the cell membrane. Mammalian cell membranes are complex and composed of different lipid species. Model membranes have been developed to provide an adequate environment to envisage MP reconstitution. Among them, tethered-Bilayer Lipid Membranes (tBLMs) appear as the best model because they allow the lipid bilayer to be decoupled from the support. Thus, they provide a sufficient aqueous space to envisage the proper accommodation of large extra-membranous domains of MPs, extending outside. Additionally, as the bilayer remains attached to tethers covalently fixed to the solid support, they can be investigated by a wide variety of surface-sensitive analytical techniques. This review provides an overview of the different approaches developed over the last two decades to achieve sophisticated tBLMs, with a more and more complex lipid composition and adapted for functional MP reconstitution.

Statin Type and Cancer Outcomes in Patients with Diabetes Type 2 and Solid Tumors

Objective

Type 2 diabetes mellitus (T2DM) affects 10% of Americans and is associated with an increased incidence of cancer. Statins are first-line cholesterol-lowering medications in the treatment of hyperlipidemia. Several studies have demonstrated a relationship between statin use and reduced cancer incidence. We examined the cancer benefits of statin subtypes, with specific attention to disease-free survival (DFS) and overall survival (OS).

Methods

This retrospective review included adults with T2DM diagnosed with solid tumors at Roswell Park Cancer Institute in Buffalo, NY, USA (2003-2010). Individuals with gestational diabetes, incomplete records, or diagnosed with rare solid tumors were excluded. Follow-up began at the date of diagnosis and ended with the first confirmed recurrence, death, or loss of contact. Demographics were assessed by Chi-square, Kaplan-Meier survival analyses, and Cox proportional hazards regression.

Findings

Overall, 1102 patients met inclusion criteria, 52.1% of the study participants were female, and 578 participants (52.5%) died during the follow-up period which ranged from 0 to 156 months. Hydrophilic statin use was associated with improved DFS at 5-year follow-up (41.0% vs. 36.9%, P = 0.0077) compared to lipophilic statin use. Multivariate regression revealed that hydrophilic statins were associated with improved DFS (hazard ratio [HR]: 0.706, 95% confidence interval [CI]: 0.526-0.947) and OS (HR: 0.685, 95% CI: 0.503-0.934). Pravastatin was associated with improved OS (HR: 0.674, 95% CI: 0.471-0.964).

Conclusion

In patients with T2DM and cancer, hydrophilic statins, and pravastatin in particular, are associated with improved DFS as well as OS. Further research examining the cancer-specific effects of hydrophilic and lipophilic statins is needed to better understand their beneficial effects.

Evaluation of the relationship between previous statin use and thyroid cancer using Korean National Health Insurance Service-Health Screening Cohort data

The association of thyroid cancer with statin use is controversial. This study aimed to investigate the association of previous statin use with thyroid cancer in the ≥ 40-year-old population in the Korean National Health Insurance Service-Health Screening Cohort. The 5501 patients in the thyroid cancer group were matched with the 22,004 patients in the non-thyroid cancer group for age, sex, income, and region of residence. Previous statin use during the 2 years before the diagnosis of thyroid cancer was examined. The odds ratios (ORs) with 95% confidence intervals (CIs) of previous statin use for thyroid cancer were estimated using conditional logistic regression analyses. Additionally, subgroup analyses were conducted. The thyroid cancer group showed more days of previous statin use than the non-thyroid cancer group (72.3, standard deviation [SD] = 181.2 days vs. 64.3, SD = 174.4 days, P = 0.003). Although the odds of previous statin use for thyroid cancer were high in the crude model (OR = 1.10, 95% CI 1.04–1.17, P = 0.002), they were low in the fully adjusted model (OR = 0.89, 95% CI 0.82–0.95, P = 0.001). According to age and sex subgroups, the younger (< 60 years old) male group showed lower odds for thyroid cancer according to previous statin use (adjusted OR = 0.70, 95% CI 0.55–0.88, P = 0.003), but this finding was not observed in other subgroups of older men or in any groups of women. Thyroid cancer was negatively associated with statin use in the previous 2 years in the adjusted model.

Hexyl-aminolevulinate ethosome-mediated photodynamic therapy against acne: in vitro and in vivo analyses

Biofilm formation by Propionibacterium acnes is known to cause failure of anti-acne treatment. Conventional therapies for acne are typically inadequate. Accordingly, in this study, we evaluated the therapeutic potential of photodynamic therapy (PDT) using hexyl-aminolevulinate (HAL)-loaded ethosomes (ESs) against the biofilms of P. acnes in vitro and P. acnes-induced inflammatory acne model in vivo. The antibacterial effects of HAL ESs were evaluated using XTT colorimetric assays and scanning electron microscopic observations of morphological changes. P. acnes was intradermally injected into the ears of Sprague-Dawley rats, and the anti-inflammatory effects of HAL ESs were measured by determining changes in appearance, histology, and the antibacterial effects by P. acnes abundance in ear tissues compared with blank control ESs, HAL alone, and 5-aminolevulinic acid (ALA) alone. The highest reduction in viability in P. acnes biofilms was observed after treatment with 5 mg/mL HAL ESs. Notably, blank control ESs also showed significant inhibitory effects. Furthermore, HAL ESs had superior therapeutic effects in the rat model compared with HAL or ALA solutions. The observed therapeutic effects of HAL ESs against P. acnes biofilms and P. acnes-induced inflammation suggest that PDT with HAL-loaded ESs may have potential applications in the treatment of acne.

Statin therapy and risk of Alzheimer's and age-related neurodegenerative diseases

INTRODUCTION

Establishing efficacy of and molecular pathways for statins has the potential to impact incidence of Alzheimer's and age-related neurodegenerative diseases (NDD).

METHODS

This retrospective cohort study surveyed US-based Humana claims, which includes prescription and patient records from private-payer and Medicare insurance. Claims from 288,515 patients, aged 45 years and older, without prior history of NDD or neurological surgery, were surveyed for a diagnosis of NDD starting 1 year following statin exposure. Patients were required to be enrolled with claims data for at least 6 months prior to first statin prescription and at least 3 years thereafter. Computational system biology analysis was conducted to determine unique target engagement for each statin.

RESULTS

Of the 288,515 participants included in the study, 144,214 patients (mean [standard deviation (SD)] age, 67.22 [3.8] years) exposed to statin therapies, and 144,301 patients (65.97 [3.2] years) were not treated with statins. The mean (SD) follow-up time was 5.1 (2.3) years. Exposure to statins was associated with a lower incidence of Alzheimer's disease (1.10% vs 2.37%; relative risk [RR], 0.4643; 95% confidence interval [CI], 0.44-0.49; P < .001), dementia 3.03% vs 5.39%; RR, 0.56; 95% CI, 0.54-0.58; P < .001), multiple sclerosis (0.08% vs 0.15%; RR, 0.52; 95% CI, 0.41-0.66; P < .001), Parkinson's disease (0.48% vs 0.92%; RR, 0.53; 95% CI, 0.48-0.58; P < .001), and amyotrophic lateral sclerosis (0.02% vs 0.05%; RR, 0.46; 95% CI, 0.30-0.69; P < .001). All NDD incidence for all statins, except for fluvastatin (RR, 0.91; 95% CI, 0.65-1.30; P = 0.71), was reduced with variances in individual risk profiles. Pathway analysis indicated unique and common profiles associated with risk reduction efficacy.

DISCUSSION

Benefits and risks of statins relative to neurological outcomes should be considered when prescribed for at-risk NDD populations. Common statin activated pathways indicate overarching systems required for risk reduction whereas unique targets could advance a precision medicine approach to prevent neurodegenerative diseases.

The Role of Structure and Biophysical Properties in the Pleiotropic Effects of Statins

Statins are a class of drugs used to lower low-density lipoprotein cholesterol and are amongst the most prescribed medications worldwide. Most statins work as a competitive inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGR), but statin intolerance from pleiotropic effects have been proposed to arise from non-specific binding due to poor enzyme-ligand sensitivity. Yet, research into the physicochemical properties of statins, and their interactions with off-target sites, has not progressed much over the past few decades. Here, we present a concise perspective on the role of statins in lowering serum cholesterol levels, and how their reported interactions with phospholipid membranes offer a crucial insight into the mechanism of some of the more commonly observed pleiotropic effects of statin administration. Lipophilicity, which governs hepatoselectivity, is directly related to the molecular structure of statins, which dictates interaction with and transport through membranes. The structure of statins is therefore a clinically important consideration in the treatment of hypercholesterolaemia. This review integrates the recent biophysical studies of statins with the literature on the physiological effects and provides new insights into the mechanistic cause of statin pleiotropy, and prospective means of understanding the cholesterol-independent effects of statins.

New Insights Into Targeting Membrane Lipids for Cancer Therapy

Modulation of membrane lipid composition and organization is currently developing as an effective therapeutic strategy against a wide range of diseases, including cancer. This field, known as membrane-lipid therapy, has risen from new discoveries on the complex organization of lipids and between lipids and proteins in the plasma membranes. Membrane microdomains present in the membrane of all eukaryotic cells, known as lipid rafts, have been recognized as an important concentrating platform for protein receptors involved in the regulation of intracellular signaling, apoptosis, redox balance and immune response. The difference in lipid composition between the cellular membranes of healthy cells and tumor cells allows for the development of novel therapies based on targeting membrane lipids in cancer cells to increase sensitivity to chemotherapeutic agents and consequently defeat multidrug resistance. In the current manuscript strategies based on influencing cholesterol/sphingolipids content will be presented together with innovative ones, more focused in changing biophysical properties of the membrane bilayer without affecting the composition of its constituents.