Association Between Genetically Proxied Inhibition of HMG-CoA Reductase and Epithelial Ovarian Cancer

Association of genetic variants related to combined lipid-lowering and antihypertensive therapies with risk of cardiovascular disease: 2 × 2 factorial Mendelian randomization analyses

BACKGROUND

Lipid-lowering drugs and antihypertensive drugs are commonly combined for cardiovascular disease (CVD). However, the relationship of combined medications with CVD remains controversial. We aimed to explore the associations of genetically proxied medications of lipid-lowering and antihypertensive drugs, either alone or both, with risk of CVD, other clinical and safety outcomes.

METHODS

We divided 423,821 individuals in the UK Biobank into 4 groups via median genetic scores for targets of lipid-lowering drugs and antihypertensive drugs: lower low-density lipoprotein cholesterol (LDL-C) mediated by targets of statins or proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, lower systolic blood pressure (SBP) mediated by targets of β-blockers (BBs) or calcium channel blockers (CCBs), combined genetically lower LDL-C and SBP, and reference (genetically both higher LDL-C and SBP). Associations with risk of CVD and other clinical outcomes were explored among each group in factorial Mendelian randomization.

RESULTS

Independent and additive effects were observed between genetically proxied medications of lipid-lowering and antihypertensive drugs with CVD (including coronary artery disease, stroke, and peripheral artery diseases) and other clinical outcomes (ischemic stroke, hemorrhagic stroke, heart failure, diabetes mellitus, chronic kidney disease, and dementia) (P > 0.05 for interaction in all outcomes). Take the effect of PCSK9 inhibitors and BBs on CVD for instance: compared with the reference, PCSK9 group had a 4% lower risk of CVD (odds ratio [OR], 0.96; 95%CI, 0.94-0.99), and a 3% lower risk was observed in BBs group (OR, 0.97; 95%CI, 0.94-0.99), while combined both were associated with a 6% additively lower risk (OR, 0.94; 95%CI, 0.92-0.97; P = 0.87 for interaction).

CONCLUSIONS

Genetically proxied medications of combined lipid-lowering and antihypertensive drugs have an independent and additive effects on CVD, other clinical and safety outcomes, with implications for CVD clinical practice, subsequent trials as well as drug development of polypills.

Global epidemiology of epithelial ovarian cancer

Globally, ovarian cancer is the eighth most common cancer in women, accounting for an estimated 3.7% of cases and 4.7% of cancer deaths in 2020. Until the early 2000s, age-standardized incidence was highest in northern Europe and North America, but this trend has changed; incidence is now declining in these regions and increasing in parts of eastern Europe and Asia. Ovarian cancer is a very heterogeneous disease and, even among the most common type, namely epithelial ovarian cancer, five major clinically and genetically distinct histotypes exist. Most high-grade serous ovarian carcinomas are now recognized to originate in the fimbrial ends of the fallopian tube. This knowledge has led to more cancers being coded as fallopian tube in origin, which probably explains some of the apparent declines in ovarian cancer incidence, particularly in high-income countries; however, it also suggests that opportunistic salpingectomy offers an important opportunity for prevention. The five histotypes share several reproductive and hormonal risk factors, although differences also exist. In this Review, we summarize the epidemiology of this complex disease, comparing the different histotypes, and consider the potential for prevention. We also discuss how changes in the prevalence of risk and protective factors might have contributed to the observed changes in incidence and what this might mean for incidence in the future.

Association between genetically proxied PCSK9 inhibition and systemic lupus erythematosus risk: A mendelian randomization study

BACKGROUND

Preclinical and epidemiological studies suggest that proprotein convertase subtilisin/kexin type 9 (PCSK9) had a potential effect on the development of SLE, but it was unclear whether a causal relationship exists. We aimed to investigate the association between genetically proxied inhibition of PCSK9 and the risk of SLE using a two-sample Mendelian randomization (MR) approach.

METHODS

Single nucleotide polymorphisms (SNPs) associated with PCSK9 were extracted from pooled data obtained from the Global Lipid Genetics Consortium (GLGC) Genome-wide Association Study (GWAS) related to LDL-c levels, which was used as a proxy for PCSK9 inhibition. Pooled statistics for SLE were obtained from an independent GWAS dataset including 5201 SLE patients and 9066 controls. Inverse variance-weighted random-effects models were used to examine the association between genetically proxied inhibition of PCSK9 and the risk of SLE. MR-Egger, weighted median, weighted mode, Simple mode, and co-location analyses were used as sensitivity analyses to test the robustness of the analyses.

RESULTS

Genetically proxied inhibition of PCSK9 was associated with a reduced risk of SLE (OR = 0.51, 95% CI = 0.34 to 0.77, p = .001). This finding was replicated in an earlier GLGC GWAS analysis (OR = 0.59, 95% CI = 0.40 to 0.87, p = .007). Sensitivity analysis ensured that the results were robust. Co-localization analysis did not find evidence of shared causal variation between PCSK9 and SLE.

CONCLUSIONS

This Mendelian randomization study showed that PCSK9 was associated with SLE pathogenesis, and its inhibition was associated with a reduced risk of SLE. This study has offered a prospective therapeutic avenue for intervening in the progression of SLE by inhibiting PCSK9 levels.

Causal role of lipid metabolism in pulmonary alveolar proteinosis: an observational and mendelian randomisation study

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare interstitial lung disease characterised by the accumulation of lipoprotein material in the alveoli. Although dyslipidaemia is a prominet feature, the causal effect of lipid traits on PAP remains unclear. This study aimed to explore the role of lipid traits in PAP and evaluate the potential of lipid-lowering drug targets in PAP.

METHODS

Clinical outcomes, lipid profiles and lung function tests were analysed in a clinical cohort of diagnosed PAP patients and propensity score-matched healthy controls. Genome-wide association study data on PAP, lipid metabolism, blood cells and variants of genes encoding potential lipid-lowering drug targets were obtained for Mendelian randomisation (MR) and mediation analyses.

FINDINGS

Observational results showed that higher levels of total cholesterol (TC), triglycerides and low-density lipoprotein (LDL) were associated with increased risks of PAP. Higher levels of TC and LDL were also associated with worse PAP severity. In MR analysis, elevated LDL was associated with an increased risk of PAP (OR: 4.32, 95% CI: 1.63 to 11.61, p=0.018). Elevated monocytes were associated with a lower risk of PAP (OR 0.34, 95% CI: 0.18 to 0.66, p=0.002) and mediated the risk impact of LDL on PAP. Genetic mimicry of PCSK9 inhibition was associated with a reduced risk of PAP (OR 0.03, p=0.007).

INTERPRETATION

Our results support the crucial role of lipid and metabolism-related traits in PAP risk, emphasising the monocyte-mediated, causal effect of elevated LDL in PAP genetics. PCSK9 mediates the development of PAP by raising LDL. These finding provide evidence for lipid-related mechanisms and promising lipid-lowering drug target for PAP.

Genetic evidence implicating circulating lipids and lipid drug targets in pterygium

There is limited knowledge about the impact of circulating lipids and lipid-modifying drugs on pterygium development, with conflicting results reported. Our study aimed to address these questions by applying the Mendelian randomization (MR) approach. A two-step MR model was developed. In the first step, bidirectional two-sample MR was employed to establish the causal relationship between circulating lipids and pterygium risk. In the second step, drug-target MR analysis was conducted to assess the causal effect of proprotein convertase subtilisin/kexin type 9 (PCSK9) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) inhibitors on pterygium outcomes. Genetically predicted low-density lipoprotein cholesterol (LDL-c) levels were found to be significantly associated with an increased risk of pterygium (Inverse variance weighted [IVW] odds ratio [OR] = 2.227; P = 1.53 × 10-4). Similarly, higher total cholesterol (TC) levels exhibited a suggestive association with greater susceptibility to pterygium (IVW OR = 1.806; P = 1.70 × 10-3). Through drug-target MR, a positive causal association was noted between HMGCR-mediated LDL-c levels and pterygium (IVW OR = 6.999; P = 0.016), suggesting that statins may be effective in reducing pterygium risk. The present findings suggest that circulating TC and LDL-c are risk factors for pterygium. Additionally, the results indicate that HMGCR inhibitors, which lower LDL-c levels, have a potential protective effect on pterygium outcomes. Further research is warranted to elucidate the underlying mechanisms involved in pterygium pathogenesis, with a particular focus on cholesterol metabolism.

Evaluation of the Effect of Sodium-Glucose Cotransporter 2 Inhibition on Fracture Risk: Evidence From Mendelian Randomization and Genetic Association Study

This study aims to evaluate the causal effect of sodium-glucose cotransporter 2 (SGLT2) inhibition on bone mineral density (BMD), osteoporosis, and fracture risk using genetics. Two-sample Mendelian randomization (MR) analyses were performed utilizing two sets of genetic variants as instruments (six and two single-nucleotide polymorphisms [SNPs]) associated with SLC5A2 gene expression and glycated hemoglobin A1c levels. Summary statistics of BMD from the Genetic Factors for Osteoporosis consortium (BMD for total body, n = 66,628; femoral neck, n = 32,735; lumbar spine, n = 28,498; forearm, n = 8143) and osteoporosis (6303 cases, 325,717 controls) and 13 types of fracture (≤17,690 cases, ≤328,382 controls) data from the FinnGen study were obtained. One-sample MR and genetic association analyses were conducted in UK Biobank using the individual-level data of heel BMD (n = 256,286) and incident osteoporosis (13,677 cases, 430,262 controls) and fracture (25,806 cases, 407,081 controls). Using six SNPs as the instrument, genetically proxied SGLT2 inhibition showed little evidence of association with BMD of total body, femoral neck, lumbar spine, and forearm (all p ≥ 0.077). Similar results were observed using two SNPs as instruments. Little evidence was found for the SGLT2 inhibition effect on osteoporosis (all p ≥ 0.112) or any 11 major types of fracture (all p ≥ 0.094), except for a nominal significance for fracture of lower leg (p = 0.049) and shoulder and upper arm (p = 0.029). One-sample MR and genetic association analysis showed that both the weighted genetic risk scores constructed from the six and two SNPs were not causally associated with heel BMD, osteoporosis, and fracture (all p ≥ 0.387). Therefore, this study does not support an effect of genetically proxied SGLT2 inhibition on fracture risk. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Genetically instrumented LDL-cholesterol lowering and multiple disease outcomes: A Mendelian randomization phenome-wide association study in the UK Biobank

AIMS

Lipid-lowering medications are widely used to control blood cholesterol levels and manage a range of cardiovascular and lipid disorders. We aimed to explore the possible associations between LDL lowering and multiple disease outcomes or biomarkers.

METHODS

We performed a Mendelian randomization phenome-wide association study (MR-PheWAS) in 337 475 UK Biobank participants to test for associations between four proposed LDL-C-lowering genetic risk scores (PCSK9, HMGCR, NPC1L1 and LDLR) and 1135 disease outcomes, with follow-up MR analyses in 52 serum, urine, imaging and clinical biomarkers. We used inverse-variance weighted MR in the main analyses and complementary MR methods (weighted median, weighted mode, MR-Egger and MR-PRESSO) as sensitivity analyses. We accounted for multiple testing with false discovery rate correction (P < 2.0 × 10-4 for phecodes, P < 1.3 × 10-2 for biomarkers).

RESULTS

We found evidence for an association between genetically instrumented LDL lowering and 10 distinct disease outcomes, suggesting potential causality. All genetic instruments were associated with hyperlipidaemias and cardiovascular diseases in the expected directions. Biomarker analyses supported an effect of LDL-C lowering through PCSK9 on lung function (FEV [beta per 1 mg/dL lower LDL-C -1.49, 95% CI -2.21, -0.78]; FVC [-1.42, 95% CI -2.29, -0.54]) and through HMGCR on hippocampal volume (beta per 1 mg/dL lower LDL-C 6.09, 95% CI 1.74, 10.44).

CONCLUSIONS

We found genetic evidence to support both positive and negative effects of LDL-C lowering through all four LDL-C-lowering pathways. Future studies should further explore the effects of LDL-C lowering on lung function and changes in brain volume.

Dysregulation of Cholesterol Homeostasis in Ovarian Cancer

Cholesterol plays an essential role in maintaining the rigidity of cell membranes and signal transduction. Various investigations confirmed empirically that the dysregulation of cholesterol homeostasis positively correlates with tumor progression. More specifically, recent studies suggested the distinct role of cholesterol in ovarian cancer cell proliferation, metastasis and chemoresistance. In this review, we summarize the current findings that suggest the contribution of cholesterol homeostasis dysregulation to ovarian cancer progression and resistance to anti-cancer agents. We also discuss the therapeutic implications of cholesterol-lowering drugs in ovarian cancer.

Assessing the Impact of PCSK9 and HMGCR Inhibition on Liver Function: Drug-Target Mendelian Randomization Analyses in Four Ancestries

BACKGROUND & AIMS

Observational studies have linked lipid-lowering drug targets pro-protein convertase subtilisin/kexin 9 (PCSK9) and HMG-CoA reductase (HMGCR) with adverse liver outcomes; however, liver disease incidence varies across diverse populations, and the long-term hepatic impact of these lipid-lowering drugs among non-white Europeans remains largely unknown.

METHODS

We use single nucleotide polymorphisms (SNPs) in PCSK9 and HMGCR loci from genome-wide association study data of low-density lipoprotein cholesterol in 4 populations (East Asian [EAS], South Asian [SAS], African [AFR], and European [EUR]) to perform drug-target Mendelian randomization investigating relationships between PCSK9 and HMGCR inhibition and alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and bilirubin.

RESULTS

Analyses of PCSK9 instruments, including functional variants R46L and E670G, failed to find evidence for relationships of low-density lipoprotein cholesterol lowering via PCSK9 variants and adverse effects on ALT, AST, GGT, or ALP among the cohorts. PCSK9 inhibition was associated with increased direct bilirubin levels in EUR (β = 0.089; P value = 5.69 × 10-6) and, nominally, in AFR (β = 0.181; P value = .044). HMGCR inhibition was associated with reduced AST in SAS (β = -0.705; P value = .005) and, nominally, reduced AST in EAS (β = -0.096; P value = .03), reduced ALP in EUR (β = -2.078; P value = .014), and increased direct bilirubin in EUR (β = 0.071; P value = .032). Sensitivity analyses using genetic instruments derived from circulating PCSK9 protein levels, tissue-specific PCSK9 expression, and HMGCR expression were in alignment, strengthening causal inference.

CONCLUSIONS

We did not find ALT, AST, GGT, or ALP associated with genetically proxied PCSK9 and HMGCR inhibition across ancestries. We identified possible relationships in several ancestries between PCSK9 and increased direct and total bilirubin and between HMGCR and reduced AST. These findings support long-term safety profiles and low hepatotoxic risk of PCSK9 and HMGCR inhibition in diverse populations.

Metal-phenolic capsules with ROS scavenging reshape the oxidative microenvironment of atherosclerosis

Arterial injury makes the tissue in a state of high oxidative stress. At the same time, abnormal lipid metabolism can further lead to bleeding and thrombosis. Therefore, the anti-inflammatory and anti-oxidant polyphenol, EGCG was organically complexed with Fe3+ to form a metal-phenolic framework carrier. And the antihyperlipidemic drug, atorvastatin (ATV) was loaded into the carrier to enhance the bioavailability, and simultaneously alleviate the oxidative stress of the inflammatory site and abnormal lipid metabolism. The results confirmed that the obtained material EGCG-Fe-ATV had good biocompatibility and biosafety effect. In addition, EGCG-Fe-ATV showed outstanding anti-inflammatory, anti-oxidant and lipid-lowering properties. These therapeutic outcomes of EGCG-Fe-ATV were achieved by reducing systemic and local oxidative stress and inflammation, alleviating inflammatory cell infiltration in plaques, and modulating lipid synthesis and transferase to alter cholesterol transport. In conclusion, the combination of metal-phenolic capsules with ATV provides a new strategy for reshaping the oxidative microenvironment of atherosclerosis.

Association between abnormal lipid metabolism and tumor

Metabolic Reprogramming is a sign of tumor, and as one of the three major substances metabolism, lipid has an obvious impact. Abnormal lipid metabolism is related to the occurrence of various diseases, and the proportion of people with abnormal lipid metabolism is increasing year by year. Lipid metabolism is involved in the occurrence, development, invasion, and metastasis of tumors by regulating various oncogenic signal pathways. The differences in lipid metabolism among different tumors are related to various factors such as tumor origin, regulation of lipid metabolism pathways, and diet. This article reviews the synthesis and regulatory pathways of lipids, as well as the research progress on cholesterol, triglycerides, sphingolipids, lipid related lipid rafts, adipocytes, lipid droplets, and lipid-lowering drugs in relation to tumors and their drug resistance. It also points out the limitations of current research and potential tumor treatment targets and drugs in the lipid metabolism pathway. Research and intervention on lipid metabolism abnormalities may provide new ideas for the treatment and survival prognosis of tumors.

Profiling the metabolome of uterine fluid for early detection of ovarian cancer

Ovarian cancer (OC) causes high mortality in women because of ineffective biomarkers for early diagnosis. Here, we perform metabolomics analysis on an initial training set of uterine fluid from 96 gynecological patients. A seven-metabolite-marker panel consisting of vanillylmandelic acid, norepinephrine, phenylalanine, beta-alanine, tyrosine, 12-S-hydroxy-5,8,10-heptadecatrienoic acid, and crithmumdiol is established for detecting early-stage OC. The panel is further validated in an independent sample set from 123 patients, discriminating early OC from controls with an area under the curve (AUC) of 0.957 (95% confidence interval [CI], 0.894-1). Interestingly, we find elevated norepinephrine and decreased vanillylmandelic acid in most OC cells, resulting from excess 4-hydroxyestradiol that antagonizes the catabolism of norepinephrine by catechol-O-methyltransferase. Moreover, exposure to 4-hydroxyestradiol induces cellular DNA damage and genomic instability that could lead to tumorigenesis. Thus, this study not only reveals metabolic features in uterine fluid of gynecological patients but also establishes a noninvasive approach for the early diagnosis of OC.

Targeting the mevalonate pathway suppresses ARID1A-inactivated cancers by promoting pyroptosis

ARID1A, encoding a subunit of the SWI/SNF complex, is mutated in ∼50% of clear cell ovarian carcinoma (OCCC) cases. Here we show that inhibition of the mevalonate pathway synergizes with immune checkpoint blockade (ICB) by driving inflammasome-regulated immunomodulating pyroptosis in ARID1A-inactivated OCCCs. SWI/SNF inactivation downregulates the rate-limiting enzymes in the mevalonate pathway such as HMGCR and HMGCS1, which creates a dependence on the residual activity of the pathway in ARID1A-inactivated cells. Inhibitors of the mevalonate pathway such as simvastatin suppresses the growth of ARID1A mutant, but not wild-type, OCCCs. In addition, simvastatin synergizes with anti-PD-L1 antibody in a genetic OCCC mouse model driven by conditional Arid1a inactivation and in a humanized immunocompetent ARID1A mutant patient-derived OCCC mouse model. Our data indicate that inhibition of the mevalonate pathway simultaneously suppresses tumor cell growth and boosts antitumor immunity by promoting pyroptosis, which synergizes with ICB in suppressing ARID1A-mutated cancers.

The Role of Statins in the Prevention of Ovarian and Endometrial Cancers

Ovarian and endometrial cancers are the most common gynecologic malignancies and emerging evidence suggests that lipid metabolism and subsequent inflammation are important etiologic factors for both tumors. Statins (HMG-CoA reductase inhibitors) are the most widely prescribed lipid-lowering drugs in the United States and are used by 25% of adults aged 40+ years. In addition to their cardio-protective actions, statins have anti-inflammatory effects and have demonstrated antiproliferative and apoptotic properties in cancer cell lines, supporting a potential role in cancer prevention. To appropriately quantify potential public health impact of statin use for cancer prevention, there is a great need to understand the potential risk reduction among individuals at a higher risk of gynecologic cancers, the group that will likely need to be targeted to effectively balance risk/benefit of medications repurposed for cancer prevention. In this commentary, we focus on summarizing emerging evidence suggesting that the anti-inflammatory and lipid-lowering mechanisms of statins may provide important cancer-preventive benefits for gynecologic cancers as well as outline important unanswered questions and future research directions.

Genetic association of lipids and lipid-lowering drug target genes with non-alcoholic fatty liver disease

BACKGROUND

Some observational studies found that dyslipidaemia is a risk factor for non-alcoholic fatty liver disease (NAFLD), and lipid-lowering drugs may lower NAFLD risk. However, it remains unclear whether dyslipidaemia is causative for NAFLD. This Mendelian randomisation (MR) study aimed to explore the causal role of lipid traits in NAFLD and evaluate the potential effect of lipid-lowering drug targets on NAFLD.

METHODS

Genetic variants associated with lipid traits and variants of genes encoding lipid-lowering drug targets were extracted from the Global Lipids Genetics Consortium genome-wide association study (GWAS). Summary statistics for NAFLD were obtained from two independent GWAS datasets. Lipid-lowering drug targets that reached significance were further tested using expression quantitative trait loci data in relevant tissues. Colocalisation and mediation analyses were performed to validate the robustness of the results and explore potential mediators.

FINDINGS

No significant effect of lipid traits and eight lipid-lowering drug targets on NAFLD risk was found. Genetic mimicry of lipoprotein lipase (LPL) enhancement was associated with lower NAFLD risks in two independent datasets (OR₁ = 0.60 [95% CI 0.50-0.72], p₁ = 2.07 × 10^-8; OR₂ = 0.57 [95% CI 0.39-0.82], p₂ = 3.00 × 10^-3). A significant MR association (OR = 0.71 [95% CI, 0.58-0.87], p = 1.20 × 10^-3) and strong colocalisation association (PP.H₄ = 0.85) with NAFLD were observed for LPL expression in subcutaneous adipose tissue. Fasting insulin and type 2 diabetes mediated 7.40% and 9.15%, respectively, of the total effect of LPL on NAFLD risk.

INTERPRETATION

Our findings do not support dyslipidaemia as a causal factor for NAFLD. Among nine lipid-lowering drug targets, LPL is a promising candidate drug target in NAFLD. The mechanism of action of LPL in NAFLD may be independent of its lipid-lowering effects.

FUNDING

Capital's Funds for Health Improvement and Research (2022-4-4037). CAMS Innovation Fund for Medical Sciences (CIFMS, grant number: 2021-I2M-C&T-A-010).

Association between genetically proxied PCSK9 inhibition and prostate cancer risk: A Mendelian randomisation study

BACKGROUND

Prostate cancer (PrCa) is the second most prevalent malignancy in men worldwide. Observational studies have linked the use of low-density lipoprotein cholesterol (LDL-c) lowering therapies with reduced risk of PrCa, which may potentially be attributable to confounding factors. In this study, we performed a drug target Mendelian randomisation (MR) analysis to evaluate the association of genetically proxied inhibition of LDL-c-lowering drug targets on risk of PrCa.

METHODS AND FINDINGS

Single-nucleotide polymorphisms (SNPs) associated with LDL-c (P < 5 × 10-8) from the Global Lipids Genetics Consortium genome-wide association study (GWAS) (N = 1,320,016) and located in and around the HMGCR, NPC1L1, and PCSK9 genes were used to proxy the therapeutic inhibition of these targets. Summary-level data regarding the risk of total, advanced, and early-onset PrCa were obtained from the PRACTICAL consortium. Validation analyses were performed using genetic instruments from an LDL-c GWAS conducted on male UK Biobank participants of European ancestry (N = 201,678), as well as instruments selected based on liver-derived gene expression and circulation plasma levels of targets. We also investigated whether putative mediators may play a role in findings for traits previously implicated in PrCa risk (i.e., lipoprotein a (Lp(a)), body mass index (BMI), and testosterone). Applying two-sample MR using the inverse-variance weighted approach provided strong evidence supporting an effect of genetically proxied inhibition of PCSK9 (equivalent to a standard deviation (SD) reduction in LDL-c) on lower risk of total PrCa (odds ratio (OR) = 0.85, 95% confidence interval (CI) = 0.76 to 0.96, P = 9.15 × 10-3) and early-onset PrCa (OR = 0.70, 95% CI = 0.52 to 0.95, P = 0.023). Genetically proxied HMGCR inhibition provided a similar central effect estimate on PrCa risk, although with a wider 95% CI (OR = 0.83, 95% CI = 0.62 to 1.13, P = 0.244), whereas genetically proxied NPC1L1 inhibition had an effect on higher PrCa risk with a 95% CI that likewise included the null (OR = 1.34, 95% CI = 0.87 to 2.04, P = 0.180). Analyses using male-stratified instruments provided consistent results. Secondary MR analyses supported a genetically proxied effect of liver-specific PCSK9 expression (OR = 0.90 per SD reduction in PCSK9 expression, 95% CI = 0.86 to 0.95, P = 5.50 × 10-5) and circulating plasma levels of PCSK9 (OR = 0.93 per SD reduction in PCSK9 protein levels, 95% CI = 0.87 to 0.997, P = 0.04) on PrCa risk. Colocalization analyses identified strong evidence (posterior probability (PPA) = 81.3%) of a shared genetic variant (rs553741) between liver-derived PCSK9 expression and PrCa risk, whereas weak evidence was found for HMGCR (PPA = 0.33%) and NPC1L1 expression (PPA = 0.38%). Moreover, genetically proxied PCSK9 inhibition was strongly associated with Lp(a) levels (Beta = -0.08, 95% CI = -0.12 to -0.05, P = 1.00 × 10-5), but not BMI or testosterone, indicating a possible role for Lp(a) in the biological mechanism underlying the association between PCSK9 and PrCa. Notably, we emphasise that our estimates are based on a lifelong exposure that makes direct comparisons with trial results challenging.

CONCLUSIONS

Our study supports a strong association between genetically proxied inhibition of PCSK9 and a lower risk of total and early-onset PrCa, potentially through an alternative mechanism other than the on-target effect on LDL-c. Further evidence from clinical studies is needed to confirm this finding as well as the putative mediatory role of Lp(a).

Genotype-driven NPC1L1 and PCSK9 inhibition and reduced risk of periodontitis

AIM

Epidemiological and pre-clinical studies suggest a chemoprotective role of lipid-lowering agents in periodontitis. We tested the association of genetically proxied inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), Niemann-Pick C1-Like 1 (NPC1L1) and proprotein convertase subtilisin/kexin type 9 (PCSK9) with periodontitis.

MATERIALS AND METHODS

Genetic variants in HMGCR, NCP1L1 and PCSK9 associated with low-density lipoprotein (LDL) cholesterol in a genome-wide association study (GWAS) meta-analysis (N = 188,578) were used to proxy therapeutic inhibition of HMGCR, NPC1L1 and PCSK9. For these genetic variants, associations with periodontitis were obtained from GWAS of 17,353 cases and 28,210 controls in the GeneLifestyle Interactions in Dental Endpoints consortium. Generalized weighted least squares analysis accounted for linkage disequilibrium of genotypes to derive pooled estimates.

RESULTS

While genetically proxied HMGCR inhibition equivalent to 1 mmol/L reduction in LDL was not associated with odds of periodontitis (odds ratio [OR] = 0.92 [95% confidence interval [CI]: 0.73; 1.16]; p = .4905; false discovery rate [FDR] = 0.4905), genetically proxied NPC1L1 (OR = 0.53 [95% CI: 0.35; 0.81]; p = .0038; FDR = 0.0077) and PCSK9 (OR = 0.84 [95% CI: 0.74; 0.95]; p = .0051; FDR = 0.0077) inhibition lowered the odds of periodontitis.

CONCLUSIONS

Genetically proxied inhibition of NCP1L1 and PCSK9 was associated with lower odds of periodontitis.

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.

Cholesterol: An important actor on the cancer immune scene

Based on the structural and signaling roles of cholesterol, which are necessary for immune cell activity, high concentrations of cholesterol and its metabolites not only trigger malignant cell activities but also impede immune responses against cancer cells. To proliferate and evade immune responses, tumor cells overcome environmental restrictions by changing their metabolic and signaling pathways. Overexpression of mevalonate pathway enzymes and low-density lipoprotein receptor cause elevated cholesterol synthesis and uptake, respectively. Accordingly, cholesterol can be considered as both a cause and an effect of cancer. Variations in the effects of blood cholesterol levels on the outcome of different types of cancer may depend on the stage of cancer. However, positive effects of cholesterol-lowering drugs have been reported in the treatment of patients with some malignancies.

Statins as Repurposed Drugs in Gynecological Cancer: A Review

Discovering new drugs is an expensive and time-consuming process, including target identification, bioavailability, pharmacokinetic (PK) tests, pharmacodynamic (PD) tests, toxicity profiles, recommended dosage test, and observation of the side effects, etc. Repurposed drugs could bypass some steps, starting from phase II trials, and shorten the processes. Statins, also known as HMG-CoA inhibitors (HMGCR), are commonly used to manage and prevent various cardiovascular diseases and have been shown to improve the morbidity and mortality of patients. In addition to the inhibitory effects on the production of cholesterol, the beneficial effects of statins on the prognosis and risk of various cancers are also shown. Statins not only inhibited cell proliferation, metastasis, and chemoresistance but affected the tumor microenvironment (TME). Thus, statins have great potential to be repurposed in oncology. Hence, we review the meta-analysis, cohort, and case-control studies of statins in gynecological cancers, and elucidate how statins regulate cell proliferation, apoptosis, tumor growth, and metastasis. Although the results in gynecological cancers remain controversial and the effects of different statins in different histotypes of gynecological cancers and TME are needed to elucidate further, statins are excellent candidates and worthy of being repurposed drugs in treating gynecological cancers.

Comparing the Relationships of Genetically Proxied PCSK9 Inhibition With Mood Disorders, Cognition, and Dementia Between Men and Women: A Drug‐Target Mendelian Randomization Study

Background

PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors are important therapeutic options for reducing cardiovascular disease risk; however, questions remain regarding potential differences in the neuropsychiatric impact of long‐term PCSK9 inhibition between men and women.

Methods and Results

Using PCSK9 gene single‐nucleotide polymorphisms from European ancestry–based genome‐wide association studies of low‐density lipoprotein cholesterol (N=1 320 016), circulating PCSK9 protein levels (N=10 186), tissue‐specific PCSK9 gene expression, sex‐specific genome‐wide association studies of anxiety, depression, cognition, insomnia, and dementia (ranging from 54 321 to 194 174), we used drug‐target inverse variance–weighted Mendelian randomization (MR) and complementary MR methods (MR Egger, weighted median, and weighted mode) to investigate potential neuropsychiatric consequences of genetically proxied PCSK9 inhibition in men and women. We failed to find evidence surpassing correction for multiple comparisons of relationships between genetically proxied PCSK9 inhibition and the risk for the 12 neuropsychiatric end points in either men or women. Drug‐target analyses were generally well‐powered to detect effect estimates at several hypothesized thresholds for both combined‐sex and sex‐specific end points, especially analyses using PCSK9 instruments derived from protein and expression quantitative trait loci. Further, MR estimates across complementary MR methods and additional models using genetic instruments derived from circulating PCSK9 protein levels and tissue‐specific PCSK9 expression were in alignment, strengthening causal inference.

Conclusions

Genetically proxied PCSK9 inhibition showed a neutral neuropsychiatric side effect profile with no major sex‐specific differences. Given statistical power considerations, replication with larger samples, as well as data from other ancestral populations, are necessary. These findings may have important clinical implications for lipid‐lowering drug‐prescribing practices and side effect monitoring of approved and future PCSK9 therapies.

Lipid metabolism in pancreatic cancer: emerging roles and potential targets

Pancreatic cancer is one of the most serious health issues in developed and developing countries, with a 5-year overall survival rate currently <9%. Patients typically present with advanced disease due to vague symptoms or lack of screening for early cancer detection. Surgical resection represents the only chance for cure, but treatment options are limited for advanced diseases, such as distant metastatic or locally progressive tumors. Although adjuvant chemotherapy has improved long-term outcomes in advanced cancer patients, its response rate is low. So, exploring other new treatments is urgent. In recent years, increasing evidence has shown that lipid metabolism can support tumorigenesis and disease progression as well as treatment resistance through enhanced lipid synthesis, storage, and catabolism. Therefore, a better understanding of lipid metabolism networks may provide novel and promising strategies for early diagnosis, prognosis estimation, and targeted therapy for pancreatic cancer patients. In this review, we first enumerate and discuss current knowledge about the advances made in understanding the regulation of lipid metabolism in pancreatic cancer. In addition, we summarize preclinical studies and clinical trials with drugs targeting lipid metabolic systems in pancreatic cancer. Finally, we highlight the challenges and opportunities for targeting lipid metabolism pathways through precision therapies in pancreatic cancer.

Postmenopausal Women with Breast, Endometrial, and Ovarian Cancers Have an Increased Risk for Cardiovascular Conditions prior to Active Endocrine Therapy

Background

Patients with active cancer have an increased risk of cardiovascular diseases (CVDs) among cancer patients receiving endocrine therapy. However, little research has explored the distribution of CVD comorbidities and cardiovascular risk factors (CVRFs) among postmenopause women with breast, endometrial, or ovarian cancer prior to active treatment with endocrine therapy. We aimed to explore the distribution of CVD comorbidities and associated CVRF in patients suffering from breast, endometrial, or ovarian cancer prior to the use of endocrine therapy and to assess whether there was compliance with existing hospital recommendations, particularly on the use of lipid-lowering agents to prevent the development of CVD comorbidities in postmenopause women.

Methods

A total of 10,731 postmenopause women with primary breast, endometrial, or ovarian cancer were enrolled between 30th May 2008 and 31st July 2021 from an electronic health record database at the first affiliated hospital of Dalian Medical University. Dyslipidemia was defined according to 2016 Chinese guidelines for adults. Multivariate logistic regression analysis was used to identify the independent predictors of CVD comorbidities in breast, endometrial, and ovarian cancers separately.

Results

Overall, 18.9% of the included women had at least one CVD record before endocrine therapy. The highest prevalence of CVD was identified for hypertension (16.5%), followed by coronary heart disease (4.5%), stroke (2.1%), heart failure (1.2%), and atrial fibrillation (1.1%). The most common CVRF among total cancer patients was dyslipidemia, with a remarkable prevalence of 62.8%, followed by diabetes mellitus (8.6%). Notably, only 11.1% of cancer patients were receiving lipid-lowering agents.

Conclusion

Cancer patients with potential eligibility for endocrine therapy use had an increased risk for CVD comorbidities. Dyslipidemia was the common CVRF. Compliance with recommendations for preventing and managing these comorbidities requires serious attention.

The role of NPC1L1 in cancer

Lipid metabolism appears to play significant roles in the development of cancer. Numerous studies have shown that the evolution of malignancies, including breast, prostate, and colorectal cancers, involves cholesterol in a profound manner. A crucial part in the intestinal absorption of cholesterol is played by Niemann–Pick C1-like 1 (NPC1L1), a cholesterol transporter protein that is widely expressed in the small intestine and liver. The importance of NPC1L1 in tumor prognosis has been demonstrated in investigations in the interim. NPC1L1 also has the potential to develop into a new therapeutic target and a cancer marker. There is, however, no comprehensive review that summarizes NPC1L1’s function in cancer. To this end, we outlined NPC1L1’s functions in carcinogenesis and treatment, along with resources that can be used to further comprehend the connection between NPC1L1 and tumors.

High-affinity SOAT1 ligands remodeled cholesterol metabolism program to inhibit tumor growth

BACKGROUND

Although cholesterol metabolism is a common pathway for the development of antitumor drugs, there are no specific targets and drugs for clinical use. Here, based on our previous study of sterol O-acyltransferase 1 (SOAT1) in hepatocelluar carcinoma, we sought to screen an effective targeted drug for precise treatment of hepatocelluar carcinoma and, from the perspective of cholesterol metabolism, clarify the relationship between cholesterol regulation and tumorigenesis and development.

METHODS

In this study, we developed a virtual screening integrated affinity screening technology for target protein drug screening. A series of in vitro and in vivo experiments were used for drug activity verification. Multi-omics analysis and flow cytometry analysis were used to explore antitumor mechanisms. Comparative analysis of proteome and transcriptome combined with survival follow-up information of patients reveals the clinical therapeutic potential of screened drugs.

RESULTS

We screened three compounds, nilotinib, ABT-737, and evacetrapib, that exhibited optimal binding with SOAT1. In particular, nilotinib displayed a high affinity for SOAT1 protein and significantly inhibited tumor activity both in vitro and in vivo. Multi-omics analysis and flow cytometry analysis indicated that SOAT1-targeting compounds reprogrammed the cholesterol metabolism in tumors and enhanced CD8⁺ T cells and neutrophils to suppress tumor growth.

CONCLUSIONS

Taken together, we reported several high-affinity SOAT1 ligands and demonstrated their clinical potential in the precision therapy of liver cancer, and also reveal the potential antitumor mechanism of SOAT1-targeting compounds.

Cholesterol homeostasis and cancer: a new perspective on the low-density lipoprotein receptor

BACKGROUND

Disturbance of cholesterol homeostasis is considered as one of the manifestations of cancer. Cholesterol plays an essential role in the pleiotropic functions of cancer cells, including mediating membrane trafficking, intracellular signal transduction, and production of hormones and steroids. As a single transmembrane receptor, the low-density lipoprotein receptor (LDLR) can participate in intracellular cholesterol uptake and regulate cholesterol homeostasis. It has recently been found that LDLR is aberrantly expressed in a broad range of cancers, including colon cancer, prostate cancer, lung cancer, breast cancer and liver cancer. LDLR has also been found to be involved in various signaling pathways, such as the MAPK, NF-κB and PI3K/Akt signaling pathways, which affect cancer cells and their surrounding microenvironment. Moreover, LDLR may serve as an independent prognostic factor for lung cancer, breast cancer and pancreatic cancer, and is closely related to the survival of cancer patients. However, the role of LDLR in some cancers, such as prostate cancer, remains controversial. This may be due to the lack of normal feedback regulation of LDLR expression in cancer cells and the severe imbalance between LDLR-mediated cholesterol uptake and de novo biosynthesis of cholesterol.

CONCLUSIONS

The imbalance of cholesterol homeostasis caused by abnormal LDLR expression provides new therapeutic opportunities for cancer. LDLR interferes with the occurrence and development of cancer by modulating cholesterol homeostasis and may become a novel target for the development of anti-cancer drugs. Herein, we systematically review the contribution of LDLR to cancer progression, especially its dysregulation and underlying mechanism in various malignancies. Besides, potential targeting and immunotherapeutic options are proposed.

Associations between Genetically Proxied Inhibition of Lipid-Lowering Drug Targets and Serum Micronutrients among Individuals of European Descent: A Mendelian Randomization Study

BACKGROUND

Limited and inconclusive data exist concerning the associations between lipid-lowering drugs and serum micronutrient concentrations.

METHODS

We conducted Mendelian randomization (MR) analyses to explore the associations between lipid-lowering drug targets and serum micronutrients. Single-nucleotide polymorphisms in genes encoding molecular targets of LDL cholesterol-lowering therapies were selected as instrumental variables for 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR; target of statins), proprotein convertase subtilisin/kexin type 9 (PCSK9; target of PCSK9 inhibitors), and Niemann-Pick C1-Like 1 (NPC1L1; target of ezetimibe). Exposure data were extracted from a published genome-wide association study (GWAS) of lipids in 188,577 European individuals, with outcome data obtained from the Integrative Epidemiology Unit (IEU) GWAS database (https://gwas.mrcieu.ac.uk). Overall, age and sex information were not calculable from the summary-level GWAS data. MR analyses were performed using the inverse-variance weighted method and MR sensitivity analysis methods.

RESULTS

We found genetically proxied inhibition of HMGCR to lower iron (effect, -0.16; 95% CI: -0.27, -0.06; P value = 0.003), zinc (effect, -0.83; 95% CI: -1.36, -0.31; P value = 0.002), magnesium (effect, -0.17; 95% CI: -0.27, -0.06; P value = 0.003), potassium (effect, -0.17; 95% CI: -0.27, -0.06; P value = 0.002), genetically proxied inhibition of NPC1L1 to increase calcium (effect, 0.28; 95% CI: 0.10, 0.46; P value = 0.003), retinol (effect, 0.25; 95% CI: 0.07, 0.44; P value = 0.01), and genetically proxied inhibition of PCSK9 to increase vitamin D (effect, 0.10; 95% CI: 0.07, 0.12; P value = 1.8 × 10-19). These associations were robust in MR sensitivity analyses. However, the associations between genetically proxied inhibition of HMGCR and NPC1L1 and the micronutrients were not consistent in multiple comparisons.

CONCLUSIONS

Our results provide evidence that statin use may lower serum concentrations of iron, zinc, magnesium, and potassium, PCSK9 inhibitors may increase serum vitamin D, and ezetimibe may increase serum calcium and retinol concentrations.

Cardio-Oncology: A Myriad of Relationships Between Cardiovascular Disease and Cancer

Cardiovascular disease (CVD) and cancer are the leading causes of death worldwide. With an increasing number of the elderly population, and early cancer screening and treatment, the number of cancers cases are rising, while the mortality rate is decreasing. However, the number of cancer survivors is increasing yearly. With the prolonged life span of cancer patients, the adverse effects of anti-tumor therapy, especially CVD, have gained enormous attention. The incidence of cardiovascular events such as cardiac injury or cardiovascular toxicity is higher than malignant tumors' recurrence rate. Numerous clinical studies have also shifted their focus from the study of a single disease to the interdisciplinary study of oncology and cardiology. Previous studies have confirmed that anti-tumor therapy can cause CVD. Additionally, the treatment of CVD is also related to the tumors incidence. It is well established that the increased incidence of CVD in cancer patients is probably due to an unmodified unhealthy lifestyle among cancer survivors or cardiotoxicity caused by anti-cancer therapy. Nevertheless, some patients with CVD have a relatively increased cancer risk because CVD and malignant tumors are highly overlapping risk factors, including gender, age, hypertension, diabetes, hyperlipidemia, inflammation, and obesity. With advancements in the diagnosis and treatment, many patients simultaneously suffer from CVD and cancer, and most of them have a poor prognosis. Therefore, clinicians should understand the relationship between CVD and tumors, effectively identify the primary and secondary prevention for these diseases, and follow proper treatment methods.

Investigating the effects of statins on ischemic heart disease allowing for effects on body mass index: a Mendelian randomization study

Despite effective lipid reduction and corresponding benefits for cardiovascular disease prevention and treatment, statins have pleiotropic effects potentially increasing the risk of ischemic heart disease (IHD), particularly by increasing body mass index (BMI). We assessed whether the effects of genetically mimicked statins on IHD were strengthened by adjusting for BMI in men and women. We also assessed if increasing BMI was specific to statins in comparison to other major lipid-lowering treatments in current use, i.e., proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors and ezetimibe. Using univariable and multivariable Mendelian randomization (MR) we found genetically mimicked effects of statins increased BMI (0.33, 95% confidence interval (CI) 0.28 to 0.38), but genetically mimicked PCSK9 inhibitors and ezetimibe did not. Genetically mimicked effects of statins on IHD reduction in both sexes (odds ratio (OR) 0.55 per unit decrease in effect size of low-density lipoprotein cholesterol (LDL-c), 95% confidence interval (CI) 0.40 to 0.76), was largely similar after adjusting for BMI, in both men (OR 0.48, 95% CI 0.38 to 0.61) and women (OR 0.66, 95% CI 0.53 to 0.82). Compared with variations in PCSK9 and NPC1L1, only variation in HMGCR was associated with higher BMI. The effects on IHD of mimicking statins were similar after adjusting for BMI in both men and women. The BMI increase due to statins does not seem to be a concern as regards the protective effects of statins on IHD, however other factors driving BMI and the protective effects of statins could be.

Abnormal lipid synthesis as a therapeutic target for cancer stem cells

Cancer stem cells (CSCs) comprise a subpopulation of cancer cells with stem cell properties, which exhibit the characteristics of high tumorigenicity, self-renewal, and tumor initiation and are associated with the occurrence, metastasis, therapy resistance, and relapse of cancer. Compared with differentiated cells, CSCs have unique metabolic characteristics, and metabolic reprogramming contributes to the self-renewal and maintenance of stem cells. It has been reported that CSCs are highly dependent on lipid metabolism to maintain stemness and satisfy the requirements of biosynthesis and energy metabolism. In this review, we demonstrate that lipid anabolism alterations promote the survival of CSCs, including de novo lipogenesis, lipid desaturation, and cholesterol synthesis. In addition, we also emphasize the molecular mechanism underlying the relationship between lipid synthesis and stem cell survival, the signal trans-duction pathways involved, and the application prospect of lipid synthesis reprogramming in CSC therapy. It is demonstrated that the dependence on lipid synthesis makes targeting of lipid synthesis metabolism a promising therapeutic strategy for eliminating CSCs. Targeting key molecules in lipid synthesis will play an important role in anti-CSC therapy.

Involvement of LDL and ox-LDL in Cancer Development and Its Therapeutical Potential

Lipid metabolism disorder is related to an increased risk of tumorigenesis and is involved in the rapid growth of cancer cells as well as the formation of metastatic lesions. Epidemiological studies have demonstrated that low-density lipoprotein (LDL) and oxidized low-density lipoprotein (ox-LDL) are closely associated with breast cancer, colorectal cancer, pancreatic cancer, and other malignancies, suggesting that LDL and ox-LDL play important roles during the occurrence and development of cancers. LDL can deliver cholesterol into cancer cells after binding to LDL receptor (LDLR). Activation of PI3K/Akt/mTOR signaling pathway induces transcription of the sterol regulatory element-binding proteins (SREBPs), which subsequently promotes cholesterol uptake and synthesis to meet the demand of cancer cells. Ox-LDL binds to the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and cluster of differentiation 36 (CD36) to induce mutations, resulting in inflammation, cell proliferation, and metastasis of cancer. Classic lipid-lowering drugs, statins, have been shown to reduce LDL levels in certain types of cancer. As LDL and ox-LDL play complicated roles in cancers, the potential therapeutic effect of targeting lipid metabolism in cancer therapy warrants more investigation.

Associations of genetically proxied inhibition of HMG-CoA reductase, NPC1L1, and PCSK9 with breast cancer and prostate cancer

BACKGROUND

Preclinical and epidemiological studies indicate a potential chemopreventive role of low-density lipoprotein cholesterol (LDL-C) -lowering drugs in the risks of breast cancer and prostate cancer, but the causality remains unclear. We aimed to evaluate the association of genetically proxied inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, Niemann-Pick C1-Like 1 (NPC1L1), and proprotein convertase subtilisin/kexin type 9 (PCSK9) with risks of breast cancer and prostate cancer using a two-sample Mendelian randomization (MR) method.

METHODS

Single-nucleotide polymorphisms (SNPs) in HMGCR, NPC1L1, and PCSK9 associated with LDL-C in a genome-wide association study (GWAS) meta-analysis from the Global Lipids Genetics Consortium (GLGC; up to 188,577 European individuals) were used to proxy inhibition of HMG-CoA reductase, NPC1L1, and PCSK9. Summary statistics with outcomes were obtained from a GWAS meta-analysis of the Breast Cancer Association Consortium (BCAC; 228,951 European females) and a Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL; 140,254 European males) consortium. SNPs were combined into multiallelic models and MR estimates representing lifelong inhibition of targets were generated using the inverse-variance weighted method.

RESULTS

Genetically proxied inhibition of HMG-CoA reductase (OR: 0.84; 95% CI 0.74-0.95; P = 0.005) and NPC1L1 (OR: 0.72; 95% CI 0.58-0.90; P = 0.005) equivalent to a 1-mmol/L (38.7 mg/dL) reduction in LDL-C was associated with reduced breast cancer risk. There were no significant associations of genetically proxied inhibition of PCSK9 with breast cancer. In contrast, genetically proxied inhibition of PCSK9 (OR: 0.81; 95% CI 0.73-0.90; P < 0.001) but not HMG-CoA reductase and NPC1L1 was negatively associated with prostate cancer. In the secondary analysis, genetically proxied inhibition of HMG-CoA reductase (OR: 0.82; 95% CI 0.71-0.95; P = 0.008) and NPC1L1 (OR: 0.66; 95% CI 0.50-0.86; P = 0.002) was associated with estrogen receptor-positive breast cancer, whereas there was no association of HMG-CoA reductase and NPC1L1 with estrogen receptor-negative breast cancer.

CONCLUSIONS

Genetically proxied inhibition of HMG-CoA reductase and NPC1L1 was significantly associated with lower odds of breast cancer, while genetically proxied inhibition of PCSK9 was associated with reduced risk of prostate cancer. Further randomized controlled trials are needed to confirm the respective roles of these LDL-C-lowering drugs in breast cancer and prostate cancer.

Systematic review of Mendelian randomization studies on risk of cancer

BACKGROUND

We aimed to map and describe the current state of Mendelian randomization (MR) literature on cancer risk and to identify associations supported by robust evidence.

METHODS

We searched PubMed and Scopus up to 06/10/2020 for MR studies investigating the association of any genetically predicted risk factor with cancer risk. We categorized the reported associations based on a priori designed levels of evidence supporting a causal association into four categories, namely robust, probable, suggestive, and insufficient, based on the significance and concordance of the main MR analysis results and at least one of the MR-Egger, weighed median, MRPRESSO, and multivariable MR analyses. Associations not presenting any of the aforementioned sensitivity analyses were not graded.

RESULTS

We included 190 publications reporting on 4667 MR analyses. Most analyses (3200; 68.6%) were not accompanied by any of the assessed sensitivity analyses. Of the 1467 evaluable analyses, 87 (5.9%) were supported by robust, 275 (18.7%) by probable, and 89 (6.1%) by suggestive evidence. The most prominent robust associations were observed for anthropometric indices with risk of breast, kidney, and endometrial cancers; circulating telomere length with risk of kidney, lung, osteosarcoma, skin, thyroid, and hematological cancers; sex steroid hormones and risk of breast and endometrial cancer; and lipids with risk of breast, endometrial, and ovarian cancer.

CONCLUSIONS

Despite the large amount of research on genetically predicted risk factors for cancer risk, limited associations are supported by robust evidence for causality. Most associations did not present a MR sensitivity analysis and were thus non-evaluable. Future research should focus on more thorough assessment of sensitivity MR analyses and on more transparent reporting.

Response Predictive Markers and Synergistic Agents for Drug Repositioning of Statins in Ovarian Cancer

In the field of drug repurposing, the use of statins for treating dyslipidemia is considered promising in ovarian cancer treatment based on epidemiological studies and basic research findings. Biomarkers should be established to identify patients who will respond to statin treatment to achieve clinical application. In the present study, we demonstrated that statins have a multifaceted mode of action in ovarian cancer and involve pathways other than protein prenylation. To identify biomarkers that predict the response to statins, we subjected ovarian cancer cells to microarray analysis and calculated Pearson’s correlation coefficients between gene expression and cell survival after statin treatment. The results showed that VDAC1 and LDLRAP1 were positively and negatively correlated with the response to statins, respectively. Histoculture drug response assays revealed that statins were effective in clinical samples. We also confirmed the synergistic effects of statins with paclitaxel and panobinostat and determined that statins are hematologically safe to administer to statin-treated mice. Future clinical trials based on the expression of the biomarkers identified in this study for repurposing statins for ovarian cancer treatment are warranted.

Linear and nonlinear analyses of the association between low-density lipoprotein cholesterol and diabetes: The spurious U-curve in observational study

OBJECTIVE

Hyperlipidemia is traditionally considered a risk factor for diabetes. The effect of low-density lipoprotein cholesterol (LDL-C) is counterintuitive to diabetes. We sought to investigate the relationship between LDL-C and diabetes for better lipid management.

METHODS

We tested the shape of association between LDL-C and diabetes and created polygenic risk scores of LDL-C and generated linear Mendelian randomization (MR) estimates for the effect of LDL-C and diabetes. We evaluated for nonlinearity in the observational and genetic relationship between LDL-C and diabetes.

RESULTS

Traditional observational analysis suggested a complex non-linear association between LDL-C and diabetes while nonlinear MR analyses found no evidence for a non-linear association. Under the assumption of linear association, we found a consistently protective effect of LDL-C against diabetes among the females without lipid-lowering drugs use. The ORs were 0.84 (95% CI, 0.72-0.97, P=0.0168) in an observational analysis which was more prominent in MR analysis and suggested increasing the overall distribution of LDL-C in females led to an overall decrease in the risk of diabetes (P=0.0258).

CONCLUSIONS

We verified the liner protective effect of LDL-C against diabetes among the females without lipid-lowering drug use. Non-linear associations between LDL-C against diabetes in observational analysis are not causal.

Crosstalk between Statins and Cancer Prevention and Therapy: An Update

The importance of statins in cancer has been discussed in many studies. They are known for their anticancer properties against solid tumors of the liver or lung, as well as diffuse cancers, such as multiple myeloma or leukemia. Currently, the most commonly used statins are simvastatin, rosuvastatin and atorvastatin. The anti-tumor activity of statins is largely related to their ability to induce apoptosis by targeting cancer cells with high selectivity. Statins are also involved in the regulation of the histone acetylation level, the disturbance of which can lead to abnormal activity of genes involved in the regulation of proliferation, differentiation and apoptosis. As a result, tumor growth and its invasion may be promoted, which is associated with a poor prognosis. High levels of histone deacetylases are observed in many cancers; therefore, one of the therapeutic strategies is to use their inhibitors. Combining statins with histone deacetylase inhibitors can induce a synergistic anticancer effect.

Association between Lipid Levels and Risk for Different Types of Aneurysms: A Mendelian Randomization Study

BACKGROUND

Although the associations between serum lipid levels and aneurysms have been investigated in epidemiological studies, causality remains unknown. Thus, this study aimed to investigate the causal relationships of serum high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglyceride (TG) levels on five types of aneurysms, using genetic variants associated with four lipid traits as instrumental variables in a Mendelian randomization (MR) analysis.

METHODS

We performed two-sample Mendelian randomization (MR) analyses to evaluate the associations of HDL-C, LDL-C, TC, and TG levels with risks for five types of aneurysms and those of LDL-C- (HMGCR, NPC1L1, PCSK9, CETP, and LDLR) and TG-lowering targets (ANGPTL3 and LPL) with aneurysms.

RESULTS

The sample sizes of the included studies ranged from nearly 80,000 to 410,000. We found inverse associations between genetically predicted HDL-C levels and aortic (OR = 0.74, 95% CI = 0.65-0.85) and abdominal aortic aneurysms (0.58, 0.45-0.75). A 1-SD increase in LDL-C and TC levels was associated with increased risks for aortic (1.41, 1.26-1.58 and 1.36, 1.18-1.56, respectively) and abdominal aortic aneurysms (1.82, 1.48-2.22 and 1.55, 1.25-1.93, respectively). TG levels were significantly associated with aortic (1.36, 1.18-1.56) and lower extremity artery aneurysms (2.76, 1.48-5.14), but limited to cerebral aneurysm (1.23, 1.06-1.42). Secondary analyses revealed a relationship between genetically proxied LDL-C-lowering targets and all types of aneurysms; however, the drug targets remained heterogeneous. We found a weak association between TG-lowering therapies and aortic (ANGPTL3, 0.51, 0.29-0.89) and abdominal aortic aneurysms (LPL, 0.64, 0.44-0.94).

CONCLUSION

According to genetic evidence, lipid dysfunction is a causal risk factor for aneurysms. Lipid-lowering drugs may be a potential effective strategy in preventing and managing aneurysms.

Association Between Genetically Proxied Lipid-Lowering Drug Targets and Renal Cell Carcinoma: A Mendelian Randomization Study

Observational studies suggested inconsistent associations between lipid-lowering drugs, such as statins, and renal cell carcinoma (RCC) risk. In a two-sample Mendelian randomization (MR) framework, we assessed the causal influence of lipid-lowering agents and circulating lipid traits on overall and sex-specific RCC risk. Genetic variants of six drug-target genes were selected to proxy the effects of low-density lipoprotein cholesterol (LDL-C) lowering therapies. Instrumental variables for circulating lipid traits were constructed from two large genome-wide association studies. We used endpoints for RCC from summary statistics of two studies [International Agency for Research on Cancer [IARC], N = 13,230; National Cancer Institute [NCI], N = 4,735]. The robustness of results was assessed through conventional MR sensitivity analyses. Overall, there was no significant association between genetically proxied HMG-CoA reductase (HMGCR) inhibition and RCC risk [Odds ratio [OR] = 1.42, 95% CI, 0.29–6.99]. In the sex-stratified analysis, we observed a positive association for genetically proxied drug targets with RCC risk. Specifically, genetically proxied proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition was associated with a higher risk of RCC in men [OR = 2.20 [95% CI, 1.24–3.89]], and the difference by sex was moderate. This study suggested genetically proxied inhibition of HMGCR was not associated with RCC risk, while genetically proxied PCSK9 inhibition might be associated with a higher risk of RCC in male.

Smoking is significantly associated with increased risk of COVID-19 and other respiratory infections

Observational studies suggest smoking, cannabis use, alcohol consumption, and substance use disorders (SUDs) may impact risk for respiratory infections, including coronavirus 2019 (COVID-2019). However, causal inference is challenging due to comorbid substance use. Using summary-level European ancestry data (>1.7 million participants), we performed single-variable and multivariable Mendelian randomization (MR) to evaluate relationships between substance use behaviors, COVID-19 and other respiratory infections. Genetic liability for smoking demonstrated the strongest associations with COVID-19 infection risk, including the risk for very severe respiratory confirmed COVID-19 (odds ratio (OR) = 2.69, 95% CI, 1.42, 5.10, P-value = 0.002), and COVID-19 infections requiring hospitalization (OR = 3.49, 95% CI, 2.23, 5.44, P-value = 3.74 × 10-8); these associations generally remained robust in models accounting for other substance use and cardiometabolic risk factors. Smoking was also strongly associated with increased risk of other respiratory infections, including asthma-related pneumonia/sepsis (OR = 3.64, 95% CI, 2.16, 6.11, P-value = 1.07 × 10-6), chronic lower respiratory diseases (OR = 2.29, 95% CI, 1.80, 2.91, P-value = 1.69 × 10-11), and bacterial pneumonia (OR = 2.14, 95% CI, 1.42, 3.24, P-value = 2.84 × 10-4). We provide strong genetic evidence showing smoking increases the risk for COVID-19 and other respiratory infections even after accounting for other substance use behaviors and cardiometabolic diseases, which suggests that prevention programs aimed at reducing smoking may be important for the COVID-19 pandemic and have substantial public health benefits.

HMG-Coenzyme A Reductase as a Drug Target for the Prevention of Ankylosing Spondylitis

Statins are an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR). Growing evidence indicates that statins may have an anti-inflammatory effect. Whether genetically proxied HMGCR inhibition can reduce the risk of ankylosing spondylitis is unknown. We constructed an HMGCR genetic score comprising nearly randomly inherited variants significantly associated with LDL cholesterol levels within ± 100 kb from HMGCR to proxy for inhibition of HMGCR. We also constructed PCSK9 and NPC1L1 scores as well as the LDL polygenetic score to proxy for the inhibition of these drug targets as well as serum LDL cholesterol levels, respectively. We then compared the associations of these genetic scores with the risk of ankylosing spondylitis. Of 33,998 participants in the primary cohort, 12,596 individuals had been diagnosed with ankylosing spondylitis. Genetically proxied inhibition of HMGCR scaled to per mmol/L decrease in LDL cholesterol levels by the HMGCR score was associated with a lower risk of ankylosing spondylitis (OR, 0.57; 95% CI, 0.38–0.85; P value = 5.7 × 10^–3). No significant association with ankylosing spondylitis was observed for the PCSK9 score (OR, 0.89; 95% CI, 0.68–1.16) and the NPC1L1 score (OR, 1.50; 95% CI, 0.39–5.77). For the LDL score, genetically determined per mmol/L decrease in LDL cholesterol levels led to a reduced risk of ankylosing spondylitis (OR, 0.64; 95% CI, 0.43–0.94), with significant heterogeneity and pleiotropy in the estimate. Exploratory analyses showed that genetically proxied inhibition of HMGCR appeared to have a similar effect to long-term statin therapy in modifying the risk of coronary artery disease and type 2 diabetes, suggesting that the HMGCR score might be a reliable model to assess the effect of statin. Genetically proxied inhibition of HMGCR was associated with a decreased risk of ankylosing spondylitis. This mechanism-based estimate was in line with existing observations suggesting the clinical benefits of statin therapy for ankylosing spondylitis.

Statin use and survival among women with ovarian cancer: an Australian national data-linkage study

BACKGROUND

Five-year ovarian cancer survival rates are below 50%; there is considerable interest in whether common medications like statins may improve survival.

METHODS

We identified women diagnosed with ovarian cancer in Australia from 2003 to 2013 through the Australian Cancer Database and linked these records to national medication and death databases. We used Cox proportional hazards regression to estimate hazard ratios (HR) and confidence intervals (CI) for associations between statins and survival.

RESULTS

Pre-diagnosis statin use was not associated with survival overall but was associated with better survival among women with endometrioid cancers. Statin use after diagnosis was associated with better ovarian cancer-specific survival (OVS, HR = 0.87, 95%CI 0.81-0.94), but this association was largely restricted to women who started using statins after their cancer diagnosis (OVS HR = 0.68, 0.57-0.81 vs. HR = 0.94, 0.87-1.01 for continuing users). The association was strongest for endometrioid cancers (OVS HR = 0.48, 0.29-0.77).

CONCLUSIONS

Use of statins may confer a survival benefit for women with ovarian cancer but it is impossible to rule out bias in observational studies. Particularly problematic are reverse causation where disease status affects statin use, confounding by indication and the absence of data for women with normal cholesterol levels. A randomised trial is required to provide definitive evidence.

Associations of preoperative serum high-density lipoprotein cholesterol and low-density lipoprotein cholesterol levels with the prognosis of ovarian cancer

BACKGROUND

The effect of serum lipids on ovarian cancer is controversial. We conducted this study to evaluate the prognostic value of preoperative plasma lipid profile in patients with ovarian cancer.

METHODS

The medical records of 156 epithelial ovarian cancer patients who underwent surgical resection in our department were retrospectively reviewed and analyzed. Serum lipids profiles, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), apolipoprotein A-I (apoA-I), apolipoprotein B (apoB) and clinicopathologic data, were analyzed. Cox proportional hazards regression analyses and Kaplan-Meier method were performed to evaluate the overall survival (OS) and progression-free survival (PFS).

RESULTS

Multivariable Cox regression analysis found that preoperative higher LDL-C level was significantly associated with worse OS (HR 2.088, 95% CI 1.052-4.147, p = 0.035), whereas higher HDL-C level showed significant association with better PFS (HR 0.491, 95% CI 0.247-0.975, p = 0.042). Further Kaplan-Meier survival analysis demonstrated that OS was longer for patients with low levels of LDL-C (< 2.76 mmol/L) compared to those with high levels of LDL-C (≥ 2.76 mmol/L) (P = 0.028), and PFS was better for patients with high levels of HDL-C (≥ 1.19 mmol/L) compared to those with low levels of HDL-C (< 1.19 mmol/L) (P = 0.001).

CONCLUSIONS

Preoperative HDL-C and LDL-C levels are significant predictors of clinical outcome in patients with epithelial ovarian cancer.

Review of Mendelian Randomization Studies on Ovarian Cancer

Ovarian cancer (OC) is one of the deadliest gynecological cancers worldwide. Previous observational epidemiological studies have revealed associations between modifiable environmental risk factors and OC risk. However, these studies are prone to confounding, measurement error, and reverse causation, undermining robust causal inference. Mendelian randomization (MR) analysis has been established as a reliable method to investigate the causal relationship between risk factors and diseases using genetic variants to proxy modifiable exposures. Over recent years, MR analysis in OC research has received extensive attention, providing valuable insights into the etiology of OC as well as holding promise for identifying potential therapeutic interventions. This review provides a comprehensive overview of the key principles and assumptions of MR analysis. Published MR studies focusing on the causality between different risk factors and OC risk are summarized, along with comprehensive analysis of the method and its future applications. The results of MR studies on OC showed that higher BMI and height, earlier age at menarche, endometriosis, schizophrenia, and higher circulating β-carotene and circulating zinc levels are associated with an increased risk of OC. In contrast, polycystic ovary syndrome; vitiligo; higher circulating vitamin D, magnesium, and testosterone levels; and HMG-CoA reductase inhibition are associated with a reduced risk of OC. MR analysis presents a2 valuable approach to understanding the causality between different risk factors and OC after full consideration of its inherent assumptions and limitations.

Enzymes in the Cholesterol Synthesis Pathway: Interactomics in the Cancer Context

A global protein interactome ensures the maintenance of regulatory, signaling and structural processes in cells, but at the same time, aberrations in the repertoire of protein-protein interactions usually cause a disease onset. Many metabolic enzymes catalyze multistage transformation of cholesterol precursors in the cholesterol biosynthesis pathway. Cancer-associated deregulation of these enzymes through various molecular mechanisms results in pathological cholesterol accumulation (its precursors) which can be disease risk factors. This work is aimed at systematization and bioinformatic analysis of the available interactomics data on seventeen enzymes in the cholesterol pathway, encoded by HMGCR, MVK, PMVK, MVD, FDPS, FDFT1, SQLE, LSS, DHCR24, CYP51A1, TM7SF2, MSMO1, NSDHL, HSD17B7, EBP, SC5D, DHCR7 genes. The spectrum of 165 unique and 21 common protein partners that physically interact with target enzymes was selected from several interatomic resources. Among them there were 47 modifying proteins from different protein kinases/phosphatases and ubiquitin-protein ligases/deubiquitinases families. A literature search, enrichment and gene co-expression analysis showed that about a quarter of the identified protein partners was associated with cancer hallmarks and over-represented in cancer pathways. Our results allow to update the current fundamental view on protein-protein interactions and regulatory aspects of the cholesterol synthesis enzymes and annotate of their sub-interactomes in term of possible involvement in cancers that will contribute to prioritization of protein targets for future drug development.

A phenome-wide association study of genetically mimicked statins

BACKGROUND

Beyond their success in cardiovascular disease prevention, statins are increasingly recognized to have sex-specific pleiotropic effects. To gain additional insight, we characterized associations of genetically mimicked statins across the phenotype sex-specifically. We also assessed whether any apparently non-lipid effects identified extended to genetically mimicking other widely used lipid modifiers (proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors and ezetimibe) or were a consequence of low-density lipoprotein cholesterol (LDL-c).

METHODS

We performed a sex-specific phenome-wide association study assessing the association of genetic variants in HMGCR, mimicking statins, with 1701 phenotypes. We used Mendelian randomization (MR) to assess if any non-lipid effects found were evident for genetically mimicked PCSK9 inhibitors and ezetimibe or for LDL-c.

RESULTS

As expected, genetically mimicking statins was inversely associated with LDL-c, apolipoprotein B (ApoB), and total cholesterol (TC) and positively associated with glycated hemoglobin (HbA1c) and was related to body composition. Genetically mimicking statins was also inversely associated with serum calcium, sex hormone-binding globulin (SHBG), and platelet count and positively associated with basal metabolic rate (BMR) and mean platelet volume. Stronger associations with genetically mimicked statins were evident for women than men for lipid traits (LDL-c, ApoB, and TC), calcium, and SHBG, but not for platelet attributes, body composition, or BMR. Genetically mimicking PCSK9 inhibitors or ezetimibe was also associated with lower lipids, but was not related to calcium, SHBG, BMR, or body composition. Genetically higher LDL-c increased lipids and decreased BMR, but did not affect calcium, HbA1c, platelet attributes, or SHBG with minor effects on body composition.

CONCLUSIONS

Similar inverse associations were found for genetically mimicking statins on lipid traits in men and women as for other lipid modifiers. Besides the positive associations with HbA1c, BMI (which may explain the higher BMR), and aspects of body composition in men and women, genetically mimicking statins was additionally associated with platelet attributes in both sexes and was inversely associated with serum calcium and SHBG in women. This genetic evidence suggests potential pathways that contribute to the effects of statins particularly in women. Further investigation is needed to confirm these findings and their implications for clinical practice.

Proprotein convertase subtilisin/kexin type 9 (PCSK9): A potential multifaceted player in cancer

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as a novel pharmacological target for hypercholesterolemia and associated cardiovascular diseases owing to its function to mediate the degradation of low-density lipoprotein receptor (LDLR). Findings over the past two decades have identified novel binding partners and cellular functions of PCSK9. Notably, PCSK9 is aberrantly expressed in a broad spectrum of cancers and apparently contributes to disease prognosis, indicating that PCSK9 could be a valuable cancer biomarker. Experimental studies demonstrate the contribution of PCSK9 in various aspects of cancer, including cell proliferation, apoptosis, invasion, metastasis, anti-tumor immunity and radioresistance, strengthening the idea that PCSK9 could be a promising therapeutic target. Here, we comprehensively review the involvement of PCSK9 in cancer, summarizing its aberrant expression, association with disease prognosis, biological functions and underlying mechanisms in various malignancies. Besides, we highlight the potential of PCSK9 as a future therapeutic target in personalized cancer medicine.

Integrating genomics with biomarkers and therapeutic targets to invigorate cardiovascular drug development

Drug development in cardiovascular disease is stagnating, with lack of efficacy and adverse effects being barriers to innovation. Human genetics can provide compelling evidence of causation through approaches such as Mendelian randomization, with genetic support for causation increasing the probability of a clinical trial succeeding. Mendelian randomization applied to quantitative traits can identify risk factors for disease that are both causal and amenable to therapeutic modification. However, important differences exist between genetic investigations of a biomarker (such as HDL cholesterol) and a drug target aimed at modifying the same biomarker of interest (such as cholesteryl ester transfer protein), with implications for the methodology, interpretation and application of Mendelian randomization to drug development. Differences include the comparative nature of the genetic architecture - that is, biomarkers are typically polygenic, whereas protein drug targets are influenced by either cis-acting or trans-acting genetic variants - and the potential for drug targets to show disease associations that might differ from those of the biomarker that they are intended to modify (target-mediated pleiotropy). In this Review, we compare and contrast the use of Mendelian randomization to evaluate potential drug targets versus quantitative traits. We explain how genetic epidemiological studies can be used to assess the aetiological roles of biomarkers in disease and to prioritize drug targets, including designing their evaluation in clinical trials.

PCSK9 and cancer: Rethinking the link

BACKGROUND

Cancer is emerging as a major problem globally, as it accounts for the second cause of death despite medical advances. According to epidemiological and basic studies, cholesterol is involved in cancer progression and there are abnormalities in cholesterol metabolism of cancer cells including prostate, breast, and colorectal carcinomas. However, the importance of cholesterol in carcinogenesis and thereby the role of cholesterol homeostasis as a therapeutic target is still a debated area in cancer therapy. Proprotein convertase subtilisin/kexin type-9 (PCSK9), a serine protease, modulates cholesterol metabolism by attachment to the LDL receptor (LDLR) and reducing its recycling by targeting the receptor for lysosomal destruction. Published research has shown that PCSK9 is also involved in degradation of other LDLR family members namely very-low-density-lipoprotein receptor (VLDLR), lipoprotein receptor-related protein 1 (LRP-1), and apolipoprotein E receptor 2 (ApoER2). As a result, this protein represents an interesting therapeutic target for the treatment of hypercholesterolemia. Interestingly, clinical trials on PCSK9-specific monoclonal antibodies have reported promising results with high efficacy in lowering LDL-C and in turn reducing cardiovascular complications. It is important to note that PCSK9 mediates several other pathways apart from its role in lipid homeostasis, including antiviral activity, hepatic regeneration, neuronal apoptosis, and modulation of various signaling pathways. Furthermore, recent literature has illustrated that PCSK9 is closely associated with incidence and progression of several cancers. In a number of studies, PCSK9 siRNA was shown to effectively suppress the proliferation and invasion of the several studied tumor cells. Hence, a novel application of PCSK9 inhibitors/silencers in cancer/metastasis could be considered. However, due to poor data on effectiveness and safety of PCSK9 inhibitors in cancer, the impact of PCSK9 inhibition in these pathological conditions is still unknown.

SEARCH METHODS

A vast literature search was conducted to find intended studies from 1956 up to 2020, and inclusion criteria were original peer-reviewed publications.

PURPOSE OF REVIEW

To date, PCSK9 has been scantly investigated in cancer. The question that needs to be discussed is "How does PCSK9 act in cancer pathophysiology and what are the risks or benefits associated to its inhibition?". We reviewed the available publications highlighting the contribution of this proprotein convertase in pathways related to cancer, with focus on the potential implications of its long-term pharmacological inhibition in cancer therapy.