Statin Resistance Research Articles

Lipoprotein, Cholesterol, Treatment Strategies, and its Impact on Cardiovascular Diseases

A main cause of death internationally, cardiovascular (CV) illness accounted for about 31.4% of fatalities worldwide in 2012. According to estimates, a 33% decline in coronary heart disease (CHD) mortality in the United States between 1980 and 2000 was caused by a decrease in total cholesterol levels. Similar declines in CHD fatalities (varying from 19% to 46%) in other wealthy nations have been linked to lower total cholesterol levels. Lipoproteins are complex particles with a central core containing cholesterol esters and triglycerides surrounded by free cholesterol, phospholipids, and apolipoproteins, which facilitate lipoprotein formation and function. However, numerous individuals do not achieve LDL-C goal values because of statin resistance or adherence to statin medication. If cholesterol targets are not achieved with statins alone, alternative medicines include ezetimibe, fibrates, and nicotinic acid. In addition, people with familial high cholesterol levels (FH). Lipoprotein may act as a proinflammatory mediator that augments the lesion formation in atherosclerotic plaques. HDL metabolism represents a major target for the development of therapies intended to reduce the risk of atherosclerotic cardiovascular disease. Individual cardiovascular preventative treatments should be targeted largely at individuals at higher risk who will benefit most, with the prevention and treatment of dyslipidemia being viewed as a crucial component of those interventions. Since statins have been demonstrated to lessen the risk of serious vascular events by lowering low-density lipoprotein cholesterol (LDL-C), they continue to be the first-choice medication.

Overcoming statin resistance in prostate cancer cells by targeting the 3-hydroxy-3-methylglutaryl-CoA-reductase

Prostate cancer is the most prevalent malignancy in men. While diagnostic and therapeutic interventions have substantially improved in recent years, disease relapse, treatment resistance, and metastasis remain significant contributors to prostate cancer-related mortality. Therefore, novel therapeutic approaches are needed. Statins are inhibitors of the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway which plays an essential role in cholesterol homeostasis. Numerous preclinical studies have provided evidence for the pleiotropic antitumor effects of statins. However, results from clinical studies remain controversial and have shown substantial benefits to even no effects on human malignancies including prostate cancer. Potential statin resistance mechanisms of tumor cells may account for such discrepancies. In our study, we treated human prostate cancer cell lines (PC3, C4–2B, DU-145, LNCaP) with simvastatin, atorvastatin, and rosuvastatin. PC3 cells demonstrated high statin sensitivity, resulting in a significant loss of vitality and clonogenic potential (up to – 70%; p < 0.001) along with an activation of caspases (up to 4-fold; p < 0.001). In contrast, C4–2B and DU-145 cells were statin-resistant. Statin treatment induced a restorative feedback in statin-resistant C4–2B and DU-145 cells through upregulation of the HMGCR gene and protein expression (up to 3-folds; p < 0.01) and its transcription factor sterol-regulatory element binding protein 2 (SREBP-2). This feedback was absent in PC3 cells. Blocking the feedback using HMGCR-specific small-interfering (si)RNA, the SREBP-2 activation inhibitor dipyridamole or the HMGCR degrader SR12813 abolished statin resistance in C4–2B and DU-145 and induced significant activation of caspases by statin treatment (up to 10-fold; p < 0.001). Consistently, long-term treatment with sublethal concentrations of simvastatin established a stable statin resistance of a PC3SIM subclone accompanied by a significant upregulation of both baseline as well as post-statin HMGCR protein (gene expression up to 70-fold; p < 0.001). Importantly, the statin-resistant phenotype of PC3SIM cells was reversible by HMGCR-specific siRNA and dipyridamole. Our investigations reveal a key role of a restorative feedback driven by the HMGCR/SREBP-2 axis in statin resistance mechanisms of prostate cancer cells.

Abstract 5873: ERα coordinates with squalene synthase to confer statin resistance in lung cancer

Abstract Statins are widely used to treat hypercholesterolemia by inhibiting hydroxymethylglutaryl coenzyme A reductase (HMGCR). Accumulating evidence suggests that statins also have protective effects against cancer recurrence. However, the role of statins in preventing lung cancer and biomarkers for predicting statin treatment response remains lacking. This study analyzes molecular features that dictate statin sensitivity in lung cancer by correlating large-scale statin sensitivity data and basal gene expression in a collection of 125 lung cancer patients. We identified a gene signature associated with lovastatin sensitivity and showed that gene expression in mesenchymal molecular features, the cholesterol biosynthesis pathway, and estrogen receptor alpha (ERα) signaling were key determinants of lovastatin sensitivity in lung cancer cells. To this end, we further discovered that overexpression of a committed step enzyme in cholesterol biosynthesis farnesyl-diphosphate farnesyltransferase 1 (FDFT1), also known as squalene synthase (SQS), is capable of activating ERα and is associated with increased statin tolerance. In clinical specimens, overexpression of SQS positively correlated with nuclear expression of ERα in lung cancer patients, and the combination of SQS and ERα is a powerful prognostic predictor for lung cancer. Activation of the SQS-ERα signaling axis and epithelial-to-mesenchymal transition (EMT) status represents two important features in determining statin sensitivity in lung cancer. Keywords: Statin, cholesterol biosynthesis, squalene synthase, estrogen receptor α, Epithelial-mesenchymal transition Citation Format: Yi-Fang Yang. ERα coordinates with squalene synthase to confer statin resistance in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5873.

CYP11A1 silencing suppresses HMGCR expression via cholesterol accumulation and sensitizes CRPC cell line DU-145 to atorvastatin

Statins, which are cholesterol synthesis inhibitors, are well-known therapeutics for dyslipidemia; however, some studies have anticipated their use as anticancer agents. However, epithelial cancer cells show strong resistance to statins through an increased expression of HMG-CoA reductase (HMGCR), an inhibitory target of statins. Castration-resistant prostate cancer (CRPC) cells synthesize androgens from cholesterol on their own. We performed suppression of CYP11A1, a rate-limiting enzyme in androgen synthesis from cholesterol, using siRNA or inhibitors, to examine the effect of steroidogenesis inhibition on statin sensitivity in CRPC cells. Here, we suggested that CYP11A1 silencing sensitized the statin-resistant CRPC cell line DU-145 to atorvastatin via HMGCR downregulation by an increase in intracellular free cholesterol. We further demonstrated that CYP11A1 silencing induced epithelial-mesenchymal transition, which converted DU-145 cells into a statin-sensitive phenotype. This suggests that concomitant use of CYP11A1 inhibitors could be an effective approach for overcoming statin resistance in CRPC. Moreover, we showed that ketoconazole, a CYP11A1 inhibitor, sensitized DU-145 cells to atorvastatin, although not all the molecular events observed in CYP11A1 silencing were reproducible. Although further studies are necessary to clarify the detailed mechanisms, ketoconazole may be effective as a concomitant drug that potentiates the anticancer effect of atorvastatin.

HMG-CoA reductase degrader, SR-12813, counteracts statin-induced upregulation of HMG-CoA reductase and augments the anticancer effect of atorvastatin

Statins are cholesterol-lowering drugs that have exhibited potential as cancer therapeutic agents. However, as some cancer cells are resistant to statins, broadening an anticancer spectrum of statins is desirable. The upregulated expression of the statin target enzyme, 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase (HMGCR), in statin-treated cancer cells is a well-known mechanism of statin resistance, which can be counteracted by the downregulation of HMGCR gene expression, or degradation of the HMGCR protein. However, the mechanism by which HMGCR degradation influences the anticancer effects of statins remain unreported. We tested the effect of the HMGCR degrader compound SR-12813 at a concentration that did not affect the growth of eight diverse tumor cell lines. Combined treatment with atorvastatin and a low concentration of SR-12813 led to lowering of increased HMGCR expression, and augmented the cytostatic effect of atorvastatin in both statin-resistant and -sensitive cancer cells compared with that of atorvastatin treatment alone. Dual-targeting of HMGCR using statins and SR-12813 (or similar compounds) could provide an improved anticancer therapeutic approach.

Inhibiting Isoprenylation Suppresses FcεRI-Mediated Mast Cell Function and Allergic Inflammation.

IgE-mediated mast cell activation is a driving force in allergic disease in need of novel interventions. Statins, long used to lower serum cholesterol, have been shown in multiple large-cohort studies to reduce asthma severity. We previously found that statins inhibit IgE-induced mast cell function, but these effects varied widely among mouse strains and human donors, likely due to the upregulation of the statin target, 3-hydroxy-3-methylgutaryl-CoA reductase. Statin inhibition of mast cell function appeared to be mediated not by cholesterol reduction but by suppressing protein isoprenylation events that use cholesterol pathway intermediates. Therefore, we sought to circumvent statin resistance by targeting isoprenylation. Using genetic depletion of the isoprenylation enzymes farnesyltransferase and geranylgeranyl transferase 1 or their substrate K-Ras, we show a significant reduction in FcεRI-mediated degranulation and cytokine production. Furthermore, similar effects were observed with pharmacological inhibition with the dual farnesyltransferase and geranylgeranyl transferase 1 inhibitor FGTI-2734. Our data indicate that both transferases must be inhibited to reduce mast cell function and that K-Ras is a critical isoprenylation target. Importantly, FGTI-2734 was effective invivo, suppressing mast cell-dependent anaphylaxis, allergic pulmonary inflammation, and airway hyperresponsiveness. Collectively, these findings suggest that K-Ras is among the isoprenylation substrates critical for FcεRI-induced mast cell function and reveal isoprenylation as a new means of targeting allergic disease.

The Changing Face of Atherosclerosis

BACKGROUND: Statins have been used for around three decades as the primary way to lower cholesterol and reduce the risk of atherosclerosis, but in some groups, statin resistance is common, and the danger of atherosclerosis is still high.CONTENT: Atherosclerosis was once believed to be caused by cholesterol and thrombotic material passively accumulating in the walls of arteries. However, current knowledge shows that the immune cells and inflammatory processes are essential in the formation, progression, and consequences of atherosclerotic lesions, characterized by a persistent inflammatory response, including thrombotic complications. Study of genetic, creating risk score for atherosclerosis, add more information to create more new therapies targeting low density lipoprotein cholesterol (LDL-C) receptor, and shows prospect.SUMMARY: Over time, atherosclerosis theories and treatment strategies have changed. While statins were widely used, they have now been supplanted by alternative options like the proprotein convertase subtilisin/kexin type 9 (PSCK9) inhibitor that manage atherosclerosis more effectively and comprehensive.KEYWORDS: atherosclerosis, cholesterol, inflammation, immune system, metabolism

Caffeine Supplementation and FOXM1 Inhibition Enhance the Antitumor Effect of Statins in Neuroblastoma.

Caffeine treatment and FOXM1 inhibition can both enhance the antitumor effect of statins by blocking the molecular and metabolic processes that confer statin resistance, indicating potential combination therapeutic strategies for neuroblastoma. See related commentary by Stouth et al., p. 2091.

Abstract 5262: Avasimibe abolishes the breast cancer preventative efficacy of statin in a spontaneous mouse model of breast cancer

Abstract Background: The cholesterol biosynthesis pathway plays a central role in the normal cellular development and carcinogenesis. Relevant to breast cancer prevention, the breast epithelium in women with atypical hyperplasia has been shown to have increased in cholesterol levels and oxidative products of cholesterol. Additionally, cholesterol pathway genes such as HMGCR and HMGCS1 are known to be upregulated during progression of breast cancer in patients. We have previously shown in SV40C3TAg mice that the cholesterol lowering drug-fluvastatin reduces breast tumor incidence and burden by 50% and have noted that the efficacy of statin is reduced due to the tight regulation of the cholesterol biosynthesis pathway through multiple restorative feedback loops, thus bypassing the effect of statin blockade. Hypothesis: We hypothesize that fluvastatin efficacy can be improved by co-targeting the restorative feedback pathways that are involved in resistance to statins. Methodology: RNA seq data from statin resistant MCF10.AT1-R cell clones was compared to the statin sensitive parental MCF10.AT1 cells in order to identify pathways and targets involved in statin resistance. Genes that were also found to be upregulated in the statin non-responders mice mammary tumors relative to responders mice were tested for dual targeting. Efficacy of avasimibe, an ACAT inhibitor, to sensitize MCF10.DCIS cells to statin therapy was studied by the colony formation assay. In vivo validation of the statin + avasimibe dual therapy was performed in SV40C3TAg mice that spontaneously develop triple negative breast cancer. Results: We found ACAT1 and ACAT2 to be overexpressed in statin resistance cell clones and non-responder mouse breast tumors. ACATs are involved in cholesterol esterification that is required for storing cholesterol in lipid droplets. Cholesterol esterification in conjunction with cholesterol synthesis and export constitute key mechanisms involved in maintaining cholesterol homeostasis. Thus, we tested if avasimibe treatment potentiates the fluvastatin efficacy to inhibit colonizing ability. Avasimibe and fluvastatin combination completely abolished the ability of MCF10.DCIS cells to form colonies. Next, we tested the efficacy of combination treatment to prevent breast tumors in SV40C3TAg mice. The treatments started at the age of 6 weeks, prior to the onset of cancer and continued until 22 weeks of age. We found fluvastatin and avasimibe combination to be completely ineffective and 90% mice developed tumors. In addition, tumor burden was not reduced with dual treatment. Conclusions: We postulate that avasimibe enhanced metabolism of fluvastatin in mouse system and thus completely abolishing the chemopreventive effects of statin. Genomically derived rationale drug combinations may result in unanticipated interactions and/or ancillary effects that limit efficacy in vivo/in patients. Citation Format: Anjana Bhardwaj, Zhenlin Ju, Alexander Koh, Rhea Bhala, Jing Wang, Isabelle Bedrosian. Avasimibe abolishes the breast cancer preventative efficacy of statin in a spontaneous mouse model of breast cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5262.

Gene signature associated with resistance to fluvastatin chemoprevention for breast cancer

BackgroundAlthough targeting of the cholesterol pathway by statins prevents breast cancer development in mouse models, efficacy is not absolute. Therefore, the goal of this study is to investigate if the upregulation in the cholesterol biosynthesis pathway genes associates with response to statin chemoprevention and may potentially be used as response biomarkers.MethodsExpression of cholesterol biosynthesis pathway genes was initially derived from the RNA sequencing of MCF10A cell line- based breast cancer progression model system and subsequently validated by quantitative PCR assay. Response to fluvastatin was assessed in vitro using the MCF10A cell line model system, including a statin resistant cell line that was generated (MCF10.AT1-R), and measured using colony forming assays. In vivo efficacy of statin for chemoprevention was assessed in the SV40C3 TAg mouse model. Mammary tumors were identified by histologic analysis of the mammary glands. Mammary glands without histologic evidence of high-grade lesions (in situ and/or invasive carcinoma) were considered responsive to statin treatment.ResultsWe found more than 70% of a published multi-gene fluvastatin resistance signature to be significantly upregulated during breast cancer progression and inversely correlated with statin inhibition of cellular growth and proliferation. This inherent statin resistance gene signature was also largely shared with the signature of acquired resistance to fluvastatin in MCF10.AT1-R cell line model of acquired statin resistance. These inherent resistance genes and genes exclusive to acquired statin resistance map to steroid-, and terpenoid backbone- biosynthesis pathway. We found upregulation of ~ 80% of cholesterol biosynthesis pathway genes in the tumor bearing mammary glands of SV40 C3TAg transgenic mouse model of TNBC, suggesting the involvement of cholesterol biosynthesis pathway in resistance to statin chemoprevention in vivo. A panel of 13-genes from the pathway significantly associated with response to statin treatment, as did the expression level of HMGCR alone in a mouse model of breast cancer suggesting their utility to predict the efficacy of statin chemoprevention.ConclusionsHigh basal level, or restorative upregulation, in the cholesterol biosynthesis pathway genes appear to be strongly associated with resistance to statin chemoprevention for breast cancer and may serve as a biomarker to tailor statin treatment to individuals who are most likely to benefit.

Ezetimibe- A Novel Add on Treatment Strategy to Achieve Targeted LDL in Patients with Uncontrolled LDL Levels on High Dose Statin Alone

Background: The lowering of low-density lipoprotein cholesterol (LDL-C) is the primary target of therapy in the primary and secondary prevention of cardiovascular events. Statins are the most prescribed lipid-lowering drugs, but many patients fail to achieve the target low-density lipoprotein (LDL) level with statin alone or at higher doses. The add-on therapy of 'Ezetimibe' to statin monotherapy has resulted in a synergistic effect in reducing LDL levels and achievements of lipid targets. Cholesterol comes from two sources. endogenous and exogenous. Rather than inhibiting one source, it is better to inhibit two sources. While statins inhibit endogenous production, Ezetimibe decreases absorption of cholesterol. Indian patients are also observed to have low HDL which is another risk factor for heart diseases. We aimed to assess the efficacy of the combination of atorvastatin plus ezetimibe in Indian patients with dyslipidemia and to see whether it can reduce LDL levels and Improve HDL and triglyceride levels. Objective: (1) To find out LDL reduction by addition of ezetimibe in combination with statin in Indian patients. (2) To find out increase in HDL levels by adding ezetimibe in combination with statin along with the reduction in triglyceride levels in Indian patients. Methods: The retrospective data from EMR of the patients diagnosed with a high level of LDL and satisfying the study's inclusion criteria were collected. The patients at the baseline were given monotherapy. Those who did not achieve the desired LDL were given treatment with Atorvastatin high dose (40 mg and 80 daily) and were allocated to the add-on therapy with Ezetimibe at 10 mg/day after 3 months. The groups (monotherapy and combined therapy) were compared at baseline and subsequent follow-up visits. Data were analyzed using R studio 1.2.1335 and Microsoft Excel. Statistical significance was considered at p&lt;0.05. Results: The LDL level showed a significant decrease after 18 months from baseline till the subsequent follow-up visits. The reduction observed in the serum concentration of LDL was from 167.95 ± 12.85 mg/dL to 91.9 ± 10.39 mg/dL (p &lt; 0.001) in 40 mg group and from 164.76 ± 9.9 mg/dL to 106.71 ± 17.17 mg/dL (p &lt; 0.001) in 80 mg group. Furthermore, the rate of achieving an LDL level &lt;100 mg/dL increased from 0% to 45.28% in the 40 mg group and from 0% to 35.24% in 80 mg group and showed significantly greater improvement (p = 0.001). Conclusion: Compared with high doses of statin, the combination of statin with Ezetimibe not only achieves targeted serum lipid levels, suggesting that combination therapy should be a priority when statin resistance or poor efficacy occurs with the higher dose of statin monotherapy. Keyword: LDL; HDL; Triglycerides; Atorvastatin; Ezetimibe

Abstract 11456: Elevated Lipoprotein(a) is Associated with Statin Resistance

Introduction: LDL-C reduction by statins is the mainstay pharmacologic strategy for ASCVD risk reduction. Despite adherence, some patients fail to achieve LDL-C goals, a phenomenon known as statin resistance. Current LDL-C assays include cholesterol content on both lipoprotein(a) [Lp(a)] and LDL particles. Because statins do not lower Lp(a), Lp(a)-cholesterol may represent a statin insensitive pool within LDL-C. Hypothesis: Elevated Lp(a) contributes to statin resistance in patients treated with high-intensity statin therapy. Methods: A secondary analysis was performed on 2338 patients from the Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) trial, randomized to receive atorvastatin 80mg or placebo; baseline and week 16 lipid parameters were analyzed. Results: In the atorvastatin group (n = 1092), mean (SD) baseline LDL-C, absolute LDL-C reduction, median percent LDL-C change from baseline (IQR), and Lp(a) were 123.8 (33.5) mg/dL, 52.2 (36.7) mg/dL, -47.6% (-59.1- -29.9%), and 10.6 (5.1-29.1) mg/dL, respectively. Median (IQR) baseline Lp(a) was higher [12.1 (5.9-38.1) vs 9.2 (4.4-22.4) mg/dL, p &lt; 0.001] in patients with attenuated percent LDL-C reduction compared to group median. The median percent LDL-C reduction on atorvastatin was 42.3% (24.3-52.5%) in patients with baseline Lp(a) between 50 - 99 mg/dL, and 32.6% (11.5-43.7%) with Lp(a) &gt; 100 mg/dL prevalent in ~10% of the population, both significantly attenuated compared to patients with Lp(a) &lt;30 mg/dL (50.4% [33.3-61.1%]), p &lt; 0.001. An LDL-C target of 70 mg/dL or less was achieved in 62.3% of patients with baseline Lp(a) &lt;30 mg/dL, compared to 55.2%, 43.3%, and 24.1% of those with Lp(a) 30 - 49 mg/dL, 50 - 99 mg/dL, and &gt; 100 mg/dL (p &lt; 0.001), respectively [Figure 1]. Conclusions: Elevated Lp(a) is associated with statin resistance and may identify patients who require additional or more potent lipid lowering therapies to achieve LDL-C goals.

Bempedoic acid: A nonstatin drug for the management of hypercholesterolemia.

Bempedoic acid: A nonstatin drug for the management of hypercholesterolemia.

Abstract 2589: Gene signature of fluvastatin resistance for prevention of breast cancer and predicting resistance to statins

Abstract Introduction: Cholesterol biosynthesis pathway is highly regulated and inhibition of the pathway with statins is known to cause restorative upregulation of several genes in the pathway. The goal of this study is to investigate if the statin mediated upregulation in the cholesterol biosynthesis pathway genes associates with the resistance to fluvastatin in a model of hormonally insensitive breast cancer Methods: A published gene signature of statin resistance was validated 1) a cell line based model of breast cancer progression consisting of inherently fluvastatin sensitive and inherently fluvastatin resistant cell lines and also compared to our experimentally derived acquired signature of fluvastatin resistance using 2) an isogenic set of cell lines consisting of a fluvastatin sensitive cell line (MCF10.AT1), and an acquired resistant cell line (MCF10.AT- R) and lastly validated using 3) SV40 C3 tag, a mouse model of hormone receptor negative breast cancer. Clariom RNA profiling were processed and mined by IPA analysis to identify the fluvastatin resistance signature that were validated by qPCR. Fluvastatin resistance was determined in vitro by colony formation assay and in vivo in a mouse model of breast cancer. Results: We found more than 75% of the published 17 gene panel fluvastatin resistance gene signature (consisting of cholesterol biosynthesis pathway genes) to be significantly upregulated in an inherently resistant cell line, DCIS cell line, relative to fluvastatin sensitive preneoplastic, MCF10.AT1 cell line. We found this inherent statin resistance gene signature to be also relevant in the MCF10.AT-R resistant cells as we found 13 of these genes to map to top 3 upregulated pathways that are steroid biosynthesis, steroid hormone biosynthesis and terpenoid backbone biosynthesis pathway. Next, we tested if 17 gene statin resistance signature associates with presence of tumors in the mammary glands of fluvastatin treated mice and found upregulation of more than 50% of the genes in the resistance signature in the tumor bearing mammary glands. Lastly, we studied if a 10-day period of fluvastatin treatment to SV40C3 Tag mice, a spontaneous mouse model of breast cancer, can also trigger the upregulation of these cholesterol biosynthesis pathway genes and provide an early signal of statin resistance. These experiments showed that a 10-day period is not long enough to cause a feedback upregulation in steroid biosynthesis pathway genes and thus can't be used a surrogate timepoint to detect resistance to fluvastatin. Conclusions: Upregulation of multiple steroid biosynthesis pathway genes after fluvastatin treatment suggests an opportunity of dual targeting of the cholesterol biosynthesis pathway in order to sensitize the fluvastatin resistant breast cancer cells. Citation Format: Anjana Bhardwaj, Zhenlin Ju, Matthew Embury, Jing Wang, Isabelle Bedrosian. Gene signature of fluvastatin resistance for prevention of breast cancer and predicting resistance to statins [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2589.

Guideline recommendations, clinical trial data, and new and emerging therapies

Nearly 93 million American adults have hyperlipidemia, a major risk factor for the development of atherosclerotic cardiovascular disease. Use of HMG-CoA reductase inhibitors (ie, statins) and ezetimibe have decreased hypercholesterolemia's prevalence in the past decade, but poor adherence is common and leads to scenarios where patients do not derive the greatest possible benefit. In addition, statin resistance may play a role when patients' LDL-C levels are not lowered to the expected extent despite good medication adherence. When statins fail to control hyperlipidemia, guidelines recommend furthering treatment by adding ezetimibe or a PCSK9 inhibitor. In November 2018, the American College of Cardiology and the American Heart Association updated their hyperlipidemia guideline. This revision recommends a more aggressive approach to hyperlipidemia. In patients who fail to respond to or cannot tolerate statins or ezetimibe, PCSK9 inhibitors are a reasonable treatment option. Large outcomes trials have compared the currently approved PCSK9 inhibitors with placebo and established that PCSK9 inhibitors lowered LDL-C by more than 50% below the statin-treated baseline and reduce cardiovascular outcomes. In addition, bempedoic acid, lomitapide, and evinacumab are available options that may be instituted in select patients. In development is inclisiran, a small interfering RNA molecule, which antagonizes PCSK9 production. With good adherence and the use of a greater assortment of medications, patients may experience atherogenic lipoprotein lowering, leading to a decrease in cardiovascular disease.

Piceatannol reduces resistance to statins in hypercholesterolemia by reducing PCSK9 expression through p300 acetyltransferase inhibition

The purpose of this study was to investigate the role of piceatannol (PT) in statin (rosuvastatin and simvastatin) resistance and tolerance and its association with PCSK9 expression via its p300 inhibitory (p300i) activity. An in vitro study was performed using HepG2 cells that were exposed to statins (rosuvastatin or simvastatin) with or without PT in delipidated serum (DLPS) medium. In the statin exposed conditions, PCSK9 expression was reduced following PT treatment when compared to HepG2 cells w/o PT treatment. Furthermore, no significant difference was observed in the expression of the transcription factors SREBP2 and HNF1α, which regulate PCSK9 expression. This resulted in low density lipoprotein receptor (LDLR) stabilization and reduced cellular cholesterol levels. This indicates that PT epigenetically controls statin-induced PCSK9 expression. Interestingly, PT attenuated p300 histone acetyltransferase (HAT) activity. Moreover, simulation of PT-p300 binding suggested that PT inhibits p300 as PT could be docked in the p300 HAT domain. Furthermore, inhibition of p300 HAT activity using C-646, a selective p300 inhibitor, or through an siRNA system effectively reduced PCSK9 induction upon statin exposure in HepG2 cells. The chromatin immunoprecipitation (ChIP) assays revealed that PT blocked the recruitment of p300 to the PCSK9 promoter region. In summary, PT attenuated statin-induced PCSK9 expression by inhibiting p300 HAT activity. Finally, co-administration of simvastatin and PT for 10 weeks further reduced plasma low-density lipoprotein-cholesterol (LDL-C) levels and stabilized the hepatic LDLR protein level compared with those resulting from single treatment of simvastatin in a high-fat diet-induced hypercholesterolemia mouse model. Our findings indicate that PT is a new nutraceutical candidate to reduce the statin resistance and tolerance that occurs in patients with hypercholesterolemia.

736-P: Two Years Moderate Resistance Training Prevents Type 2 Diabetes but Does Not Reduce Cardiovascular Risk for Patients with Prediabetes

Resistance training can decrease blood glucose, reduce fat volume and increase muscle mass, but whether long term resistance training can prevent type 2 diabetes and reduce cardiovascular risk or not remains unclear. 248 prediabetes patients enrolled in this multicentered RCT study were randomized in to 3 groups: resistance training (RT, n=82), aerobic training (AT, n=83), and control group (n=83). The participants in RT and AT groups did moderate RT or AT 3 times a week (150minutes/week) with supervision in 3 research centers for 2 years. Compared to the control group, participants in both RT group and AT group experienced a significant reduction in A1c at month 6, 12 and 24. After adjusted for age, sex, BMI, and statin use, Resistance training and aerobic training reduced type 2 diabetes risk by 58.2% (p=0.028) and 73.2% (p=0.004), respectively, but neither AT nor RT reduced cardiovascular risk (Framingham Score). In terms of remission to normal glucose tolerance (NGT), RT and AT increased the RR by 7.84 (p=0.008) and 6.68 (p=0.016), respectively. The results of this study demonstrated that 2 years moderate resistance training has comparable effects on preventing type 2 diabetes and reversing to NGT for patients with prediabetes. Disclosure Q. Lou: None.

SUN-060 Statin-Resistant Hyperlipidemia: Role of Lipoprotein (a)

BACKGROUND: Statin resistance is a term used to describe failure to reach LDL-cholesterol target values despite high dose statin therapy. Common causes for this is nonadherence to therapy and polymorphisms in mechanisms that involve lipid absorption and metablism. We report a case of a patient with resistance to high statin therapy found to have elevated lipoprotein a [Lp(a)]. CLINICAL CASE: A 30 year old Caucasian male presented with hyperlipidemia. He was diagnosed since age of 16 and reports failure to “multiple cholesterol medications”. He had a normal EKG and stress test in the past. Denies prior history of coronary events, peripheral vascular disease or stroke. Currently only medication is atorvastatin 40 mg daily which was recently started when establishing care with new PCP. Otherwise, he was not on any lipid lowering medication for the past 6 months. He adheres to low fat diet. The patient’s body mass index is 25.6. Physical exam is benign including no xanthomas, intact pulses bilaterally, and extremities warm to touch. Labs reveal normal liver function tests, TSH 1.979, HbA1c 5.2% and Lp(a) 169 nmol/L (reference < 75 nmol/L). Lipid profile without statin therapy: total cholesterol 490, triglyceride 146, HDL 52, LDL 409. After 2 months of statin therapy: total cholesterol 448, triglyceride 127, HDL 58, LDL 370. A CT coronary calcium study revealed moderate plaque on left anterior descending artery with CAC score 104.15 suggesting atherosclerotic process. DISCUSSION: The metabolism and function of Lp(a) is still not completely understood but it is known to be a risk factor for coronary heart disease, stroke, and peripheral artery disease. Lp(a) closely resembles an LDL particle with the addition of the very large apolipoprotein (a) linked onto apolipoprotein B100 by a disulfide bond. There is structural similarity between apo(a) and plasminogen and is proposed as the missing link between atherosclerosis and thrombosis. Reduced caloric intake can decrease Lp(a) but low fat diet does affect Lp(a) levels. Aspirin reduces Lp(a) by up to 80% and itself is reduces the risk of ASCVD events. Niacin has been shown to reduce Lp(a) and adverse effects can be better tolerated with aspirin but risk reduction has not been proven. PSCK9 inhibitors are newer drugs that markedly lower LDL and can modestly lower Lp(a). CONCLUSION: Statin therapy remains the foundation treatment in patients with hyperlipidemia and elevated Lp(a) despite little effect of Lp(a) due to its ability to lower ASCVD risk. Additional pharmacological agents including aspirin & PSCK9 inhibitors can be a useful adjuncts to reduce ASCVD risk despite modest Lp(a) reduction. Lipoprotein apheresis may be used in refractory cases.

Induction of 3-hydroxy-3-methylglutaryl-CoA reductase mediates statin resistance in breast cancer cells

The mevalonate pathway has emerged as a promising target for several solid tumors. Statins are inhibitors of the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme of this pathway, and are commonly used to treat patients with hypercholesterolemia. Pleiotropic antitumor mechanisms of statins have been demonstrated for several human cancer types. However, cancer cells differ in their individual statin sensitivity and some cell lines have shown relative resistance. In this study we demonstrate, that the human breast cancer cell lines MDA-MB-231, MDA-MB-468, MCF-7, and T47D are differentially affected by statins. Whereas the vitality of MDA-MB-231 and MDA-MB-468 cells was reduced by up to 60% using atorvastatin, simvastatin, or rosuvastatin (p < 0.001), only marginal effects were seen in T47D and MCF-7 cells following exposure to statins. Statin treatment led to an upregulation of HMGCR mRNA and protein expression by up to sixfolds in the statin-resistant cells lines (p < 0.001), but no alterations of HMGCR were observed in the statin-sensitive MDA-MB-231 and MDA-MB-468 cells. The knockdown of HMGCR prior to statin treatment sensitized the resistant cell lines, reflected by a 70% reduction in vitality, increased apoptotic DNA fragmentation (sixfold) and by accumulation of the apoptosis marker cleaved poly-ADP ribose polymerase. Statins induced a cleavage of the sterol-regulatory element-binding protein (SREBP)-2, a transcriptional activator of the HMGCR, in T47D and MCF-7 cells. The inhibition of SREBP-2 activation by co-administration of dipyridamole sensitized MCF-7 and T47D cells for statins (loss of vitality by 80%; p < 0.001). Furthermore, assessment of a statin-resistant MDA-MB-231 clone, generated by long-term sublethal statin exposure, revealed a significant induction of HMGCR expression by up to 12-folds (p < 0.001). Knockdown of HMGCR restored statin sensitivity back to levels of the parental cells. In conclusion, these results indicate a resistance of cancer cells against statins, which is in part due to the induction of HMGCR.

Statin resistance in Candida glabrata

Reduced efficacy of statins has been observed in people but the mechanism of this resistance is unclear and no statin-resistance mutations in the catalytic domain of HMGCR have been reported. The present study focused on looking for statin-resistance mutations and examining the mechanism of statin resistance using Candida glabrata as a model organism. C. glabrata was cultured in media containing lovastatin, simvastatin or atorvastatin to obtain lovastatin-, simvastatin- and atorvastatin-resistant mutants. A single mutant from each was purified for further analysis. In each mutant, gene sequencing showed there were no changes in the catalytic domain of HMGCR. HMGCR was overexpressed in two resistant isolates suggesting that increased production of HMGCR can lead to resistance. In a third mutant, HMGCR activity was unaltered, suggesting a non-HMGCR related mechanism, such as increased drug efflux, could be operating. Candida glabrata is a useful model organism for examining resistance to statins. Further studies are warranted to examine the precise molecular mechanisms of statin resistance.