Cholesterol and Its Derivatives: Multifaceted Players in Breast Cancer Progression

27-Hydroxycholesterol in cancer development and drug resistance

27-Hydroxycholesterol (27HC), a cholesterol metabolite, functions both as a selective oestrogen receptor (ER) modulator and a ligand for liver X receptors (LXRs). The discovery of 27HC involvement in carcinogenesis has unveiled new research avenues, yet its precise role remains controversial and context-dependent. In this review, we provide an overview of the biosynthesis and metabolism of 27HC and explore its cancer-associated signalling, with a particular focus on ER- and LXR-mediated pathways. Given the tissue-specific dual role of 27HC, we discuss its differential impact across various cancer types. Furthermore, we sort out 27HC-contributed drug resistance mechanisms from the perspectives of drug efflux, cellular proliferation, apoptosis, epithelial-mesenchymal transition (EMT), antioxidant defence, epigenetic modification, and metabolic reprogramming. Finally, we highlight the chemical inhibitors to mitigate 27HC-driven cancer progression and drug resistance. This review offers an updated role of 27HC in cancer biology, setting the stage for future research and the development of targeted therapeutics.

Cholesterol metabolism: A strategy for overcoming drug resistance in tumors

Despite significant advancements in targeted tumor therapies, the emergence of drug resistance remains a complex challenge. Cholesterol accumulation within tumor cells plays a crucial role in mediating drug resistance through various mechanisms, including altered membrane dynamics, enhanced drug efflux, and activation of survival signaling pathways. Targeting cholesterol metabolism presents an innovative strategy to enhance therapeutic sensitivity, particularly in breast cancer. Consequently, ongoing preclinical studies and clinical trials involving cholesterol-lowering agents indicate a promising direction for improving treatment outcomes in tumors. The combination of these agents with existing therapeutic regimens may lead to enhanced efficacy, highlighting the necessity for continued research in this vital area. This review examines the impact of cholesterol metabolism on drug resistance in tumors, particularly solid tumors, identifies therapeutic targets in this metabolic pathway (with a special focus on breast cancer), and discusses recent advances in cholesterol-lowering drugs in preclinical, as well as those that have entered clinical trials.

Dysregulation of cholesterol homeostasis in cancer pathogenesis

Cholesterol is a unique lipid for all mammalian cells, with important functions in membrane biogenesis and maintenance of proper membrane integrity and fluidity. Therefore, it plays an important role in cellular homeostasis. Dysregulation of cholesterol homeostasis is associated with various diseases in humans, including cardiovascular diseases, inflammatory diseases, neurodegenerative disorders, and cancers. In the tumor microenvironment, intrinsic and extrinsic cellular factors reprogram cholesterol metabolism and consequently promote tumorigenesis. Here, we summarize the current knowledge on molecular mechanisms and functional roles of cholesterol homeostasis and its dysregulation in regard to cancer pathogenesis. We also discuss the interplay of cholesterol metabolism and the ATP-binding cassette (ABC) proteins, highly conserved cellular transmembrane lipid transporters. An emerging role of lipid ABC transporters as potential prognostic tools for cancer progression and invasiveness is emphasized. Targeting both cholesterol metabolism and proteins associated with membrane cholesterol holds promise as a novel therapeutic strategy for cancer treatment.

Genetic evidence supporting the causal role of 25-hydroxyvitamin D levels in the prognosis of ER- breast cancer: A Mendelian randomization study

This study aims to investigate the connection between 25-hydroxyvitamin D (25(OH)D) levels and the prognosis of breast cancer with various estrogen receptor (ER) statuses. The summary statistics of 25(OH)D levels was obtained from a GWAS of 441,291 individuals and the information of breast cancer was collected from the Breast Cancer Association Consortium. We analyzed the causal association between 25(OH)D levels and breast cancer prognosis using a number of approaches, including inverse variance weighting (IVW). The heterogeneity test was performed using Cochran Q test. IVW, Mendelian randomization (MR)-Egger, and MR Pleiotropy RESidual Sum and Outlier methods were used for sensitivity analysis. In addition, a multivariate MR adjusted for total triglycerides, total cholesterol, and body mass index was used for further analysis. Two-sample MR results showed that 25(OH)D levels were not associated with prognosis in overall breast cancer (odds ratio [OR] = 0.93, 95% confidence interval [CI] = 0.73-1.19, IVW exam) and estrogen receptor positive (ER+) breast cancers (OR = 1.12, 95% CI = 0.77-1.63, IVW exam) and were protective associated with prognosis in estrogen receptor negative (ER-) breast cancers (OR = 0.55, 95% CI = 0.34-0.87, IVW exam). Sensitivity analysis did not observe the presence of heterogeneity and horizontal pleiotropy. In multivariate MR analysis, after adjusting for total triglycerides, total cholesterol, and body mass index, the correlation between the protective relationship between 25(OH)D levels and the prognosis for ER- breast cancer remained and became increasingly significant (OR = 0.51, 95% CI = 0.31-0.83, P = .007). This study demonstrated a protective relationship between 25(OH)D levels and the prognosis of ER- breast cancer, but there was no connection between 25(OH)D levels and the prognosis of ER+ breast cancer.

ATR promotes mTORC1 activity via de novo cholesterol synthesis

DNA damage and cellular metabolism exhibit a complex interplay characterized by bidirectional feedback mechanisms. Key mediators of the DNA damage response and cellular metabolic regulation include Ataxia Telangiectasia and Rad3-related protein (ATR) and the mechanistic Target of Rapamycin Complex 1 (mTORC1), respectively. Previous studies have established ATR as a regulatory upstream factor of mTORC1 during replication stress; however, the precise mechanisms by which mTORC1 is activated in this context remain poorly defined. Additionally, the activity of this signaling axis in unperturbed cells has not been extensively investigated. Here, we demonstrate that ATR promotes mTORC1 activity across various cellular models under basal conditions. This effect is particularly enhanced in cells following the loss of p16, which we have previously associated with hyperactivation of mTORC1 signaling and here found have increased ATR activity. Mechanistically, we found that ATR promotes de novo cholesterol synthesis and mTORC1 activation through the upregulation of lanosterol synthase (LSS), independently of both CHK1 and the TSC complex. Furthermore, the attenuation of mTORC1 activity resulting from ATR inhibition was rescued by supplementation with lanosterol or cholesterol in multiple cellular contexts. This restoration corresponded with enhanced localization of mTOR to the lysosome. Collectively, our findings demonstrate a novel connection linking ATR and mTORC1 signaling through the modulation of cholesterol metabolism.

BMP4-Induced Suppression of Breast Cancer Metastasis Is Associated with Inhibition of Cholesterol Biosynthesis

We reported previously that in preclinical models, BMP4 is a potent inhibitor of breast cancer metastasis and that high BMP4 protein levels predict favourable patient outcomes. Here, we analysed a breast cancer xenograft with or without enforced expression of BMP4 to gain insight into the mechanisms by which BMP4 suppresses metastasis. Transcriptomic analysis of cancer cells recovered from primary tumours and phosphoproteomic analyses of cancer cells exposed to recombinant BMP4 revealed that BMP4 inhibits cholesterol biosynthesis, with many genes in this biosynthetic pathway being downregulated by BMP4. The treatment of mice bearing low-BMP4 xenografts with a cholesterol-lowering statin partially mimicked the anti-metastatic activity of BMP4. Analysis of a cohort of primary breast cancers revealed a reduced relapse rate for patients on statin therapy if their tumours exhibited low BMP4 levels. These findings indicate that BMP4 may represent a predictive biomarker for the benefit of additional statin therapy in breast cancer patients.

Statins inhibit paclitaxel-induced PD-L1 expression and increase CD8+ T cytotoxicity for better prognosis in breast cancer

BACKGROUND

In recent years, the widespread use of lipid-lowering drugs, especially statins, has attracted people's attention. Statin use may be potentially associated with a reduced risk of breast cancer.

OBJECTIVE

To explore the relationship between statin use and cancer risk. And further explore the potential role of statins in the adjuvant treatment of breast cancer.

METHODS

Data for the Mendelian randomization portion of the study were obtained from genome-wide association studies of common cancers in the UK Biobank and FinnGen studies and from the Global Lipid Genetics Consortium's low density lipoprotein (LDL). In addition, the impacts of statins and chemotherapy drugs on breast cancer were examined using both in vitro and in vivo models, with particular attention to the expression levels of the immune checkpoint protein PD-L1 and its potential to suppress tumor growth.

RESULTS

Data from about 3.8 million cancer patients and ~1.3 million LDL-measuring individuals were analyzed. Genetically proxied HMGCR inhibition (statins) was associated with breast cancer risk reduction (P=0.0005). In vitro experiments showed that lovastatin significantly inhibited paclitaxel-induced PD-L1 expression and assisted paclitaxel in suppressing tumor cell growth. Furthermore, the combination therapy involving lovastatin and paclitaxel amplified CD8+ T-cell infiltration, bolstering their tumor-killing capacity and enhancing in vivo efficacy.

CONCLUSION

The utilization of statins is correlated with improved prognoses for breast cancer patients and may play a role in facilitating the transition from cold to hot tumors. Combination therapy with lovastatin and paclitaxel enhances CD8+ T-cell activity and leads to better prognostic characteristics.

Metabolome-microbiome insights into therapeutic impact of 8-O-acetylharpagide against breast cancer in a murine model

Iridoid glycosides extract, which is the main active extract of Ajuga decumbens Thunb, has been proved to have anti-breast cancer activity in previous studies. However, it is still unknown whether 8-O-acetylharpagide, a main active compound in the extract, has anti-breast cancer activity. In this study, 4 T1 breast cancer mice model was first successfully established. Then the anti-breast cancer effect of 8-O-acetylharpagide was systematically investigated. Feces were collected for metabolomics and 16S rRNA analysis to assess the potential mechanism. The results showed that 8-O-acetylharpagide was effective in reducing 4 T1 mouse tumor volume and weight compared with the model group. Metabolome analysis revealed 12 potential metabolite biomarkers in feces, mainly involved in primary bile acid biosynthesis and arachidonic acid metabolism. The 16S rRNA sequencing results demonstrated that 8-O-acetylharpagide modulated the abundance of the intestinal flora in 4 T1 mice. Spearman correlation analysis showed that calcitriol and prostaglandin G2 strongly correlated with Akkermansia, Firmicutes and Muribaculum. Overall, the active compound 8-O-acetylharpagide could inhibit significantly breast cancer growth in 4 T1 breast cancer model mice. The mechanism of the anti-breast cancer effect of 8-O-acetylharpagide may be related to the regulation of primary bile acid biosynthesis and arachidonic acid metabolism and modulation of the abundance of Akkermansia and Firmicutes.

Exploration of Novel Metabolic Features Reflecting Statin Sensitivity in Lung Cancer Cells

Statins are cholesterol-lowering drugs often used for the treatment of dyslipidemia. Statins also exert anti-cancer effects by inhibiting hydroxymethylglutaryl-CoA reductase (HMGCR), a rate-limiting enzyme in cholesterol synthesis. We previously reported that the susceptibility to statin treatment differs among cancer cells and that functional E-cadherin expression on the plasma membrane could be a biomarker of statin sensitivity in cancer cells. However, the detailed qualitative and molecular differences between statin-sensitive and statin-resistant cancer cells remain unclear. Here, we explored novel parameters related to statin sensitivity by comparing gene expression profiles and metabolite contents between statin-sensitive and statin-resistant lung cancer cell lines. We found that the expression of most cholesterol synthesis genes was lower in the statin-sensitive cancer cell line, HOP-92, than in the statin-resistant cancer cell line, NCI-H322M. Moreover, HOP-92 cells originally exhibited lower levels of CoA and HMG-CoA. Additionally, atorvastatin decreased the mRNA expression of PANK2, a rate-limiting enzyme in CoA synthesis. Atorvastatin also reduced the mRNA levels of the cholesterol esterification enzyme SOAT1, which was consistent with a decrease in the ratio of cholesterol ester to total cholesterol in HOP-92 cells. Our data suggest that the cholesterol synthetic flow and CoA content may be limited in statin-sensitive cancer cells. We also suggest that CoA synthesis and cholesterol storage may fluctuate with atorvastatin treatment in statin-sensitive cancer cells.

Advancements in Solid Lipid Nanoparticles and Nanostructured Lipid Carriers for Breast Cancer Therapy

Solid Lipid Nanocarriers (SLNs) offer a promising avenue for breast cancer treatment, a disease that accounts for 12.5% of global cancer cases. Despite strides in combined therapies (surgery, chemotherapy, radiation, and endocrine therapy), challenges like systemic toxicity, drug resistance, and adverse effects persist. The manuscript offers several novel contributions to the field of breast cancer treatment through the use of SLNs, and these are innovative drug delivery systems, multifunctionality, and biocompatibility, the potential to overcome drug resistance, integration with emerging therapies, focus on personalized medicine, ongoing and future research directions and potential for reduced side effects. SLNs present a novel strategy due to their unique physicochemical properties. They can encapsulate both hydrophilic and hydrophobic drugs, ensuring controlled release and targeted delivery, thus enhancing solubility and bioavailability and reducing side effects. The multifunctional nature of SLNs improves drug delivery while their biocompatibility supports their potential in cancer therapy. Challenges for pharmacists include maintaining stability, effective drug loading, and timed delivery. Combining SLNs with emerging therapies like gene and immunotherapy holds promise for more effective breast cancer treatments. SLNs represent a significant advancement, providing precise drug delivery and fewer side effects, with the potential for overcoming drug resistance. Ongoing research will refine SLNs for breast cancer therapy, targeting cells with minimal side effects and integrating with other treatments for comprehensive approaches. Advances in nanotechnology and personalized medicine will tailor SLNs to specific breast cancer subtypes, enhancing effectiveness. Clinical trials and new treatment developments are crucial for realizing SLNs' full potential in breast cancer care. In conclusion, SLNs offer a transformative approach to breast cancer treatment, addressing issues of drug delivery and side effects. Ongoing research aims to optimize SLNs for targeted therapy, potentially revolutionizing breast cancer care and providing hope for patients.

p140Cap modulates the mevalonate pathway decreasing cell migration and enhancing drug sensitivity in breast cancer cells

p140Cap is an adaptor protein involved in assembling multi-protein complexes regulating several cellular processes. p140Cap acts as a tumor suppressor in breast cancer (BC) and neuroblastoma patients, where its expression correlates with a better prognosis. The role of p140Cap in tumor metabolism remains largely unknown. Here we study the role of p140Cap in the modulation of the mevalonate (MVA) pathway in BC cells. The MVA pathway is responsible for the biosynthesis of cholesterol and non-sterol isoprenoids and is often deregulated in cancer. We found that both in vitro and in vivo, p140Cap cells and tumors show an increased flux through the MVA pathway by positively regulating the pace-maker enzyme of the MVA pathway, the 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR), via transcriptional and post-translational mechanisms. The higher cholesterol synthesis is paralleled with enhanced cholesterol efflux. Moreover, p140Cap promotes increased cholesterol localization in the plasma membrane and reduces lipid rafts-associated Rac1 signalling, impairing cell membrane fluidity and cell migration in a cholesterol-dependent manner. Finally, p140Cap BC cells exhibit decreased cell viability upon treatments with statins, alone or in combination with chemotherapeutic at low concentrations in a synergistic manner. Overall, our data highlight a new perspective point on tumor suppression in BC by establishing a previously uncharacterized role of the MVA pathway in p140Cap expressing tumors, thus paving the way to the use of p140Cap as a potent biomarker to stratify patients for better tuning therapeutic options.

Impact of statin use on breast cancer recurrence and mortality before and after diagnosis: a systematic review and meta-analysis

Objective

Breast cancer is one of the most common causes of death among women. Statins, typically used for cholesterol management, have been hypothesized to reduce recurrence and mortality rates in breast cancer. However, this association remains a subject of debate. This study evaluates the potential impact of statins on breast cancer recurrence and mortality.

Methods

A comprehensive search was conducted in the PubMed, EMBASE, and Cochrane databases for articles published up to June 2023. These articles examined the effect of statins on breast cancer recurrence and mortality both before and after diagnosis. The analysis was performed using random-effects models, calculating pooled hazard ratios (HR) and their 95% confidence intervals (CI).

Results

A total of 31 cohort studies, involving 261,834 female breast cancer patients, were included in this analysis. It was found that statin use prior to diagnosis was associated with a decrease in overall mortality (HR, 0.8; 95% CI, 0.69-0.93; I2 = 77.6%; P = 0.001) and breast cancer-specific mortality (HR, 0.76; 95% CI, 0.67-0.87; I2 = 72.7%; P = 0.005). Additionally, statin use after diagnosis was observed to reduce the recurrence of breast cancer (HR, 0.71; 95% CI, 0.61-0.82; I2 = 60%; P = 0.003), overall mortality (HR, 0.81; 95% CI, 0.70-0.92; I2 = 80.7%; P < 0.001), and breast cancer-specific mortality (HR, 0.76; 95% CI, 0.67-0.86; I2 = 74.5%; P < 0.001).

Conclusions

The findings of this study indicate that statin usage, both before and after breast cancer diagnosis, may be associated with reduced risks of overall and breast cancer-specific mortality, as well as lower recurrence rates.

Discretized butterfly optimization algorithm for variable selection in the rapid determination of cholesterol by near-infrared spectroscopy

The blood cholesterol level is strongly associated with cardiovascular disease. It is necessary to develop a rapid method to determine the cholesterol concentration of blood. In this study, a discretized butterfly optimization algorithm-partial least squares (BOA-PLS) method combined with near-infrared (NIR) spectroscopy is firstly proposed for rapid determination of the cholesterol concentration in blood. In discretized BOA, the butterfly vector is described by 1 or 0, which represents whether the variable is selected or not, respectively. In the optimization process, four transfer functions, i.e., arctangent, V-shaped, improved arctangent (I-atan) and improved V-shaped (I-V), are introduced and compared for discretization of the butterfly position. The partial least squares (PLS) model is established between the selected NIR variables and cholesterol concentrations. The iteration number, transfer functions and the performance of butterflies are investigated. The proposed method is compared with full-spectrum PLS, multiplicative scatter correction-PLS (MSC-PLS), max-min scaling-PLS (MMS-PLS), MSC-MMS-PLS, uninformative variable elimination-PLS (UVE-PLS), Monte Carlo uninformative variable elimination-PLS (MCUVE-PLS) and randomization test-PLS (RT-PLS). Results show that the I-V function is the best transfer function for discretization. Both preprocessing and variable selection can improve the prediction performance of PLS. Variable selection methods based on BOA are better than those based on statistics. Furthermore, I-V-BOA-PLS has the highest predictive accuracy among the seven variable selection methods. MSC-MMS can further improve the prediction ability of I-V-BOA-PLS. Therefore, BOA-PLS combined with NIR spectroscopy is promising for the rapid determination of cholesterol concentration in blood.

Increased Expression of miR-223-3p and miR-375-3p and Anti-Inflammatory Activity in HDL of Newly Diagnosed Women in Advanced Stages of Breast Cancer

The expression of inflammation-related miRs bound to high-density lipoproteins (HDLs), the anti-inflammatory activity of HDLs isolated from individuals with breast cancer, and controls were determined. Forty newly diagnosed women with breast cancer naïve of treatment and 10 control participants were included. Cholesterol-loaded bone-marrow-derived macrophages were incubated with HDL from both groups and challenged with lipopolysaccharide (LPS). Interleukin 6 (IL6) and tumor necrosis factor (TNF) in the medium were quantified. The miRs in HDLs were determined by RT-qPCR. Age, body mass index, menopausal status, plasma lipids, and HDL composition were similar between groups. The ability of HDL to inhibit IL6 and TNF production was higher in breast cancer compared to controls, especially in advanced stages of the disease. The miR-223-3p and 375-3p were higher in the HDLs of breast cancer independent of the histological type of the tumor and had a high discriminatory power between breast cancer and controls. The miR-375-3p was greater in the advanced stages of the disease and was inversely correlated with the secretion of inflammatory cytokines. Inflammation-related miRs and the anti-inflammatory role of HDLs may have a significant impact on breast cancer pathophysiology.

NUCB2/Nesfatin-1 drives breast cancer metastasis through the up-regulation of cholesterol synthesis via the mTORC1 pathway

BACKGROUND

Reprogramming lipid metabolism for tumor metastasis is essential in breast cancer, and NUCB2/Nesfatin-1 plays a crucial role in regulating energy metabolism. Its high expression is associated with poor prognosis in breast cancer. Here, we studied whether NUCB2/Nesfatin-1 promotes breast cancer metastasis through reprogramming cholesterol metabolism.

METHODS

ELISA was employed to measure the concentration of Nesfatin-1 in the serum of breast cancer patients and the control group. Database analysis suggested that NUCB2/Nesfatin-1 might be acetylated in breast cancer, which was confirmed by treating the breast cancer cells with acetyltransferase inhibitors. Transwell migration and Matrigel invasion assays were conducted, and nude mouse lung metastasis models were established to examine the effect of NUCB2/Nesfatin-1 on breast cancer metastasis in vitro and in vivo. The Affymetrix gene expression chip results were analyzed using IPA software to identify the critical pathway induced by NUCB2/Nesfatin-1. We evaluated the effect of NUCB2/Nesfatin-1 on cholesterol biosynthesis through the mTORC1-SREBP2-HMGCR axis by utilizing mTORC1 inhibitor and rescue experiments.

RESULTS

NUCB2/Nesfatin-1 was found to be overexpressed in the breast cancer patients, and its overexpression was positively correlated with poor prognosis. NUCB2 was potentially acetylated, leading to high expression in breast cancer. NUCB2/Nesfatin-1 promoted metastasis in vitro and in vivo, while Nesfatin-1 rescued impaired cell metastasis induced by NUCB2 depletion. Mechanistically, NUCB2/Nesfatin-1 upregulated cholesterol synthesis via the mTORC1 signal pathway, contributing to breast cancer migration and metastasis.

CONCLUSIONS

Our findings demonstrate that the NUCB2/Nesfatin-1/mTORC1/SREBP2 signal pathway is critical in regulating cholesterol synthesis, essential for breast cancer metastasis. Thus, NUCB2/Nesfatin-1 might be utilized as a diagnostic tool and also used in cancer therapy for breast cancer in the future.

7α,25-Dihydroxycholesterol-Induced Oxiapoptophagic Chondrocyte Death via the Modulation of p53-Akt-mTOR Axis in Osteoarthritis Pathogenesis

This study aimed to exploring the pathophysiological mechanism of 7α,25-dihydroxycholesterol (7α,25-DHC) in osteoarthritis (OA) pathogenesis. 7α,25-DHC accelerated the proteoglycan loss in ex vivo organ-cultured articular cartilage explant. It was mediated by the decreasing extracellular matrix major components, including aggrecan and type II collagen, and the increasing expression and activation of degenerative enzymes, including matrix metalloproteinase (MMP)-3 and -13, in chondrocytes cultured with 7α,25-DHC. Furthermore, 7α,25-DHC promoted caspase dependent chondrocytes death via extrinsic and intrinsic pathways of apoptosis. Moreover, 7α,25-DHC upregulated the expression of inflammatory factors, including inducible nitric oxide synthase, cyclooxygenase-2, nitric oxide, and prostaglandin E2, via the production of reactive oxygen species via increase of oxidative stress in chondrocytes. In addition, 7α,25-DHC upregulated the expression of autophagy biomarker, including beclin-1 and microtubule-associated protein 1A/1B-light chain 3 via the modulation of p53-Akt-mTOR axis in chondrocytes. The expression of CYP7B1, caspase-3, and beclin-1 was elevated in the degenerative articular cartilage of mouse knee joint with OA. Taken together, our findings suggest that 7α,25-DHC is a pathophysiological risk factor of OA pathogenesis that is mediated a chondrocytes death via oxiapoptophagy, which is a mixed mode of apoptosis, oxidative stress, and autophagy.

Finding New Molecular Targets of Two Copper(II)-Hydrazone Complexes on Triple-Negative Breast Cancer Cells Using Mass-Spectrometry-Based Quantitative Proteomics

Breast cancer is the most common cancer in women, with a high incidence estimated to reach 2.3 million by 2030. Triple-Negative Breast Cancer (TNBC) is the greatest invasive class of breast cancer with a poor prognosis, due to the side-effects exerted by the chemotherapy used and the low effectivity of novel treatments. In this sense, copper compounds have shown to be potentially effective as antitumor agents, attracting increasing interest as alternatives to the usually employed platinum-derived drugs. Therefore, the aim of this work is to identify differentially expressed proteins in MDA-MB-231 cells exposed to two copper(II)-hydrazone complexes using label-free quantitative proteomics and functional bioinformatics strategies to identify the molecular mechanisms through which these copper complexes exert their antitumoral effect in TNBC cells. Both copper complexes increased proteins involved in endoplasmic reticulum stress and unfolded protein response, as well as the downregulation of proteins related to DNA replication and repair. One of the most relevant anticancer mechanisms of action found for CuHL1 and CuHL2 was the down-regulation of gain-of-function-mutant p53. Moreover, we found a novel and interesting effect for a copper metallodrug, which was the down-regulation of proteins related to lipid synthesis and metabolism that could lead to a beneficial decrease in lipid levels.

miRNA deregulation and relationship with metabolic parameters after Mediterranean dietary intervention in BRCA-mutated women

Background

Breast cancer onset is determined by a genetics-environment interaction. BRCA1/2 gene alterations are often genetically shared in familial context, but also food intake and hormonal assessment seem to influence the lifetime risk of developing this neoplasia. We previously showed the relationship between a six-months Mediterranean dietary intervention and insulin, glucose and estradiol levels in BRCA1/2 carrier subjects. The aim of the present study was to evidence the eventual influence of this dietary intervention on the relationship between circulating miRNA expression and metabolic parameters in presence of BRCA1/2 loss of function variants.

Methods

Plasma samples of BRCA-women have been collected at the baseline and at the end of the dietary intervention. Moreover, subjects have been randomized in two groups: dietary intervention and placebo. miRNA profiling and subsequent ddPCR validation have been performed in all the subjects at both time points.

Results

ddPCR analysis confirmed that five (miR-185-5p, miR-498, miR-3910, miR-4423 and miR-4445) of seven miRNAs, deregulated in the training cohort, were significantly up-regulated in subjects after dietary intervention compared with the baseline measurement. Interestingly, when we focused on variation of miRNA levels in the two timepoints, it could be observed that miR-4423, miR-4445 and miR-3910 expressions are positively correlated with variation in vitaminD level; whilst miR-185-5p difference in expression is related to HDL cholesterol variation.

Conclusions

We highlighted the synergistic effect of a healthy lifestyle and epigenetic regulation in BC through the modulation of specific miRNAs. Different miRNAs have been reported involved in the tumor onset acting as tumor suppressors by targeting tumor-associated genes that are often downregulated.