Cholesterol and breast cancer development

Cholesterol and Cytokines: Molecular Links to Atherosclerosis and Carcinogenesis

An increase of cholesterol concentration within the artery obstructs arterial blood flow once it deposits alongside the arterial wall. This results in atherosclerosis. Carcinogenesis causes a quicker clearance of vascular cholesterol to meet the demands of tumour cell development. Both illnesses have an increased concentration of pro-inflammatory cytokines in the blood. To search the comparative characteristics of cholesterol and pro-inflammatory cytokines in the pathogenesis of atherosclerosis and carcinogenesis, a comprehensive online survey using MEDLINE, Scopus, PubMed, and Google Scholar was conducted for relevant journals with key search term cholesterol and cytokines in atherosclerotic and cancerous patients. According to reports, hypercholesterolaemia related dyslipidemia causes atherosclerosis in blood arteries and hypercholesterolaemia in cell nucleus is a reason for developing carcinogenesis. It is also noted that pro-inflammatory cytokines are involved in both of the aforementioned pathogenesis. Changes in anti-inflammatory cytokines are only the characteristic features of each kind. Thus, Cholesterol and pro-inflammatory cytokines are intensely interlinked in the genesis of atherosclerotic and carcinogenic consequences.

Erianin inhibits the progression of triple-negative breast cancer by suppressing SRC-mediated cholesterol metabolism

Triple-negative breast cancer (TNBC) is highly malignant and lacks effective biotherapeutic targets. The development of efficient anticancer drugs with low toxicity and few side effects is a hotspot in TNBC treatment research. Although erianin is known to have potent antitumor activity, its regulatory mechanism and target in TNBC have not been fully elucidated, hampering further drug development. This study showed that erianin can significantly inhibit TNBC cell proliferation and migration, promote cell apoptosis, and inhibit the growth of transplanted tumors in mice. Mechanistically, through network pharmacology analysis, molecular docking and cellular thermal shift assays, we preliminarily identified SRC as the cellular target of erianin. Erianin potently inhibited the expression of SRC, which mediated the anticancer effect of erianin in TNBC. Moreover, erianin can downregulate the expression of genes related to cholesterol synthesis and uptake by targeting SRC, interfering with cholesterol levels in TNBC, thereby inhibiting the progression of TNBC in vivo and in vitro. Taken together, our results suggest that erianin may inhibit the progression of TNBC by suppressing SRC-mediated cholesterol metabolism, and erianin has the great potential to be an effective treatment for TNBC patients.

Analysis of redox status and HDL subclasses in patients with lymphoma and the associations with FDG-PET/CT findings

Newer research points to alterations in the plasma redox status and the HDL subclass distributions in cancer. We aimed to assess the redox status and the HDL subclass distributions, lipids, and inflammatory markers in lymphoma patients in order to determine whether they were correlated with changes in FDG-PET/CT scans. At the beginning of this study, redox status, HDL subclasses, lipids, and inflammation biomarkers were determined in 58 patients with lymphoma (Hodgkin lymphoma, n=11 and non-Hodgkin lymphoma, n=47), and these same measurements were reassessed during their ensuing treatment (in 25 patients). Initially, the total oxidation status (TOS), the prooxidant-antioxidant balance (PAB), the OS index (OSI), the total protein sulfhydryl groups (SH-groups), and the advanced oxidation protein products (AOPP) were significantly higher in lymphoma patients as compared to healthy subjects, but the total antioxidant status (TAS) was significantly reduced. The PAB had a strong correlation with the CRP and interleukin-6 (rho=0.726, p<0.001; rho=0.386, p=0.003). The correlations between these parameters and the maximum standardized uptake values (SUVmax) were: PAB, rho=0.335 and p=0.010; SH-groups, rho=0.265 and p=0.044; CRP, rho=0.391 and p=0.002; HDL3b, rho=0.283 and p=0.031; HDL2b, rho= -0.294 and p=0.025; and HDL size, rho= -0.295 and p=0.024. The reductions in SUVmax between two follow-up points were associated with increases in the OSI, TOS, and SH-groups, as well as a reduction in the PAB and TAS. In conclusion, the redox parameters in patients with lymphoma were consistent with FDG-PET/CT findings. Targeting the redox status parameters and the HDL subclasses could be potential strategies in the molecular fight against lymphoma.

The Molecular and Genetic Interactions between Obesity and Breast Cancer Risk

Breast cancer (BC) is considered the leading cause of death among females worldwide. Various risk factors contribute to BC development, such as age, genetics, reproductive factors, obesity, alcohol intake, and lifestyle. Obesity is considered to be a pandemic health problem globally, affecting millions of people worldwide. Obesity has been associated with a high risk of BC development. Determining the impact of obesity on BC development risk in women by demonstrating the molecular and genetic association in pre- and post-menopause females and risk to BC initiation is crucial in order to improve the diagnosis and prognosis of BC disease. In epidemiological studies, BC in premenopausal women was shown to be protective in a certain pattern. These altered effects between the two phases could be due to various physiological changes, such as estrogen/progesterone fluctuating levels. In addition, the relationship between BC risk and obesity is indicated by different molecular alterations as metabolic pathways and genetic mutation or epigenetic DNA changes supporting a strong connection between obesity and BC risk. However, these molecular and genetic alteration remain incompletely understood. The aim of this review is to highlight and elucidate the different molecular mechanisms and genetic changes occurring in obese women and their association with BC risk and development.

Aberrant DNA Methylation, Expression, and Occurrence of Transcript Variants of the ABC Transporter ABCA7 in Breast Cancer

The ABC transporter ABCA7 has been found to be aberrantly expressed in a variety of cancer types, including breast cancer. We searched for specific epigenetic and genetic alterations and alternative splicing variants of ABCA7 in breast cancer and investigated whether these alterations are associated with ABCA7 expression. By analyzing tumor tissues from breast cancer patients, we found CpGs at the exon 5-intron 5 boundary aberrantly methylated in a molecular subtype-specific manner. The detection of altered DNA methylation in tumor-adjacent tissues suggests epigenetic field cancerization. In breast cancer cell lines, DNA methylation levels of CpGs in promoter-exon 1, intron 1, and at the exon 5-intron 5 boundary were not correlated with ABCA7 mRNA levels. By qPCR involving intron-specific and intron-flanking primers, we identified intron-containing ABCA7 mRNA transcripts. The occurrence of intron-containing transcripts was neither molecular subtype-specific nor directly correlated with DNA methylation at the respective exon-intron boundaries. Treatment of breast cancer cell lines MCF-7, BT-474, SK-BR3, and MDA-MB-231 with doxorubicin or paclitaxel for 72 h resulted in altered ABCA7 intron levels. Shotgun proteomics revealed that an increase in intron-containing transcripts was associated with significant dysregulation of splicing factors linked to alternative splicing.

Label-free and selective cholesterol detection based on multilayer functional structure coated fiber fabry-perot interferometer probe

A reflective fiber-optic Fabry-Perot cavity probe sensor is proposed to selectively measure cholesterol concentration by insert single mode fiber into ceramic tube and immobilize epoxy resin (ER)/graphene oxide (GO)/beta-cyclodextrin (β-CD) multi-layer film onto end face of ceramic tube. EDC/NHS activated GO is selected to form chemical binding with β-CD, and β-CD is the sensitive materials to bind with cholesterol molecules. With multi-layer film assisted, the sensitivity of sensor to cholesterol concentration can reach 3.92 nm/mM and the limit of detection reaches 3.48 μ M. In addition, 4 mM hemoglobin, glucose and ascorbic acid are doped into a set cholesterol sample and verified the highly selectivity of sensing cholesterol. Furthermore, the reproducibility was proved by measure the spectrum of four sensors with same fabrication process, and the reusability was also proved by repeated measurements. Overall, the sensor features with high mechanical strength, ease of fabrication, real-time monitoring, low cost and ease for measurement that given by probe structure. Therefore, the sensor provides a remarkable analytical platform for biosensing applications.

A novel micellar carrier to reverse multidrug resistance of tumours: TPGS derivatives with end-grafted cholesterol

D-α-tocopherol polyethylene glycol succinate (TPGS) has good biocompatibility, low immunogenicity, prolonged circulation time, and it can reverse multidrug resistance of tumours. However, the micelle concentration (CMC) of TPGS is too high (0.2 mg/mL) to develop the formulation of the micelle. In this study, TPGS was modified with cholesterol to obtain a new carrier material, TPGS-CHMC. The CMC of TPGS-CHMC was 2 μg/mL, which was extremely lower than that of TPGS. Docetaxel (DTX)-loaded TPGS-CHMC micelles (TPGS-CHMC/DTX) exhibited an average size of approximately 13 nm, a zeta potential of approximately -4.66 mV, and high encapsulation efficiency (99.2 ± 0.6%). TPGS-CHMC reduced mitochondrial membrane potential and cell membrane fluidity in paclitaxel-resistant ovarian cancer cells (A2780/T). In vivo, DiR-loaded TPGS-CHMC micelles were selectively distributed in A2780/T tumour-bearing nude mice. In A2780/T tumour-bearing nude mice, TPGS-CHMC/DTX micelles displayed significantly higher anti-tumour activity and less toxicity than the free DTX solution. In summary, TPGS-CHMC has various advantages, and provides a new option for developing functional polymeric micelles.

Enhanced CHOLESTEROL biosynthesis promotes breast cancer metastasis via modulating CCDC25 expression and neutrophil extracellular traps formation

Neutrophil extracellular traps (NETs) has been demonstrated to regulate the metastasis of breast cancer. In this study, we showed that de novo cholesterol biosynthesis induced by ASPP2 depletion in mouse breast cancer cell 4T1 and human breast cancer cell MDA-MB-231 promoted NETs formation in vitro, as well as in lung metastases in mice intravenously injected with ASPP2-deficient 4T1 cells. Simvastatin and berberine (BBR), cholesterol synthesis inhibitors, efficiently blocked ASPP2-depletion induced NETs formation. Cholesterol biosynthesis greatly enhanced Coiled-coil domain containing protein 25 (CCDC25) expression on cancer cells as well as in lung metastases. CCDC25 expression was co-localized with caveolin-1, a lipid raft molecule, and was damped by inhibitor of lipid rafts formation. Our data suggest that cholesterol biosynthesis promotes CCDC25 expression in a lipid raft-dependent manner. Clinically, the expression of CCDC25 was positively correlated with the expression of 3-hydroxy-3-methylglutaryl-CoAreductase (HMRCG), and citrullinated histone H3 (H3cit), in tissues from breast cancer patients. High expression of CCDC25 and HMGCR was related with worse prognosis in breast cancer patients. In conclusion, our study explores a novel mechanism for de novo cholesterol biosynthesis in the regulation of CCDC25 expression, NETs formation and breast cancer metastasis. Targeting cholesterol biosynthesis may be promising therapeutic strategies to treat breast cancer metastasis.

Anthracycline-induced cardiotoxicity: targeting high-density lipoproteins to limit the damage?

Doxorubicin (DOX) is an anthracycline antibiotic frequently used against a wide range of cancers, including breast cancer. Although the drug is effective as a treatment against cancer, many patients develop heart failure (HF) months to years following their last treatment with DOX. The challenge in preventing DOX-induced cardiotoxicity is that symptoms present after damage has already occurred in the myocardium. Therefore, early biomarkers to assess DOX-induced cardiotoxicity are urgently needed. A better understanding of the mechanisms involved in the toxicity is important as this may facilitate the development of novel early biomarkers or therapeutic approaches. In this review, we discuss the role of high-density lipoprotein (HDL) particles and its components as possible key players in the early development of DOX-induced cardiotoxicity. HDL particles exist in different subclasses which vary in composition and biological functionality. Multiple cardiovascular risk factors are associated with a change in HDL subclasses, resulting in modifications of their composition and physiological functions. There is growing evidence in the literature suggesting that cancer affects HDL subclasses and that healthy HDL particles enriched with sphingosine-1-phosphate (S1P) and apolipoprotein A1 (ApoA1) protect against DOX-induced cardiotoxicity. Here, we therefore discuss associations and relationships between HDL, DOX and cancer and discuss whether assessing HDL subclass/composition/function may be considered as a possible early biomarker to detect DOX-induced cardiotoxicity.

Possible role of lead in breast cancer - a case-control study

Numerous risk factors have been associated with breast cancer (BC), exposure to metalloestrogen, like lead, being such. Since lead involvement in BC is still equivocal, we focused on lead levels in three compartments of BC patients, blood, healthy, and malignant tissues. Also, as the cholesterol role in cancer development was recognized at the beginning of the twentieth century and led to involvement in lipid profile impairment, we further extend our research on lipid profile and enzymes responsible for maintaining lipid balance in BC patients. Fifty-five women diagnosed with BC were enrolled in the study. Forty-one healthy women represented the control group. Lead levels in blood, healthy surrounding and malignant tissue, and lipid profile parameters in serum, were determined. Higher lead levels were obtained in surrounding healthy tissue samples compared to cancerous tissue samples, while blood lead levels of BC women did not differ significantly from the control group. The altered lipid profile scheme in women diagnosed with breast cancer contained significantly higher triglycerides levels (P < 0.001). Moreover, logistic regression analysis revealed triglycerides as a significant predictor of BC (OR = 2.6; P < 0.01). Although statistical significance was missing for lower paraoxonase-1 (PON-1) activities observed in BC women, multivariate logistic regression singled out PON-1 activities as significant BC predictors. The result of the present study further indicated oxidative status imbalance and tissue levels bioelements perturbation. Obtained results in the present study propose possible lead involvement in BC onset accompanied with bioelements redistribution and oxidative stress occurrence.

Associations of the Paleolithic Diet Pattern Scores and the Risk of Breast Cancer among Adults: A Case-Control Study

Evidence suggests the role of changing traditional lifestyle patterns such as Paleolithic to modern lifestyle in the incidence and epidemic of chronic diseases. Thus, this study aimed to investigate the association between Paleolithic diet (PD) and risk of Breast Cancer (BC) in adult Iranian women. This matched case-control study included 253 women with BC and 267 healthy women aged >18 years. PD score was evaluated using a validated 168-item quantitative food frequency questionnaire. Conditional logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs), and dose-response was investigated. Mean of PD score was 39.00 ± 6.39. Among the food groups of the PD components, BC patients significantly had lower consumption of healthy food groups as vegetables, fruits, fish, and nuts, higher intakes of sugar-sweetened beverages as well as grains and starches. After adjustment for potential confounders, comparing the highest quartile of PD scores with the lowest quartile, a decrease in the risk of BC was observed for all women (OR: 0.26; 95% CI: 0.13-0.53), as well as those premenopausal (OR: 0.29; 95% CI: 0.11), and postmenopausal (OR: 0.17; 95% CI: 0.05 - 0.56). Our findings show that adherence to the PD pattern significantly reduces the risk of BC in the population studied. However, prospective studies are needed to further investigate this association.

Association of lipid profile biomarkers with breast cancer by molecular subtype: analysis of the MEND study

There is conflicting evidence on the role of lipid biomarkers in breast cancer (BC), and no study to our knowledge has examined this association among African women. We estimated odds ratios (ORs) and 95% confidence intervals (95% CI) for the association of lipid biomarkers-total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides-with odds of BC overall and by subtype (Luminal A, Luminal B, HER2-enriched and triple-negative or TNBC) for 296 newly diagnosed BC cases and 116 healthy controls in Nigeria. Each unit standard deviation (SD) increase in triglycerides was associated with 39% increased odds of BC in fully adjusted models (aOR: 1.39; 95% CI: 1.03, 1.86). Among post-menopausal women, higher total cholesterol (aOR: 1.65; 95% CI: 1.06, 2.57), LDL cholesterol (aOR: 1.59; 95% CI: 1.04, 2.41), and triglycerides (aOR: 1.91; 95% CI: 1.21, 3.01) were associated with increased odds of BC. Additionally, each unit SD increase in LDL was associated with 64% increased odds of Luminal B BC (aOR 1.64; 95% CI: 1.06, 2.55). Clinically low HDL was associated with 2.7 times increased odds of TNBC (aOR 2.67; 95% CI: 1.10, 6.49). Among post-menopausal women, higher LDL cholesterol and triglycerides were significantly associated with increased odds of Luminal B BC and HER2 BC, respectively. In conclusion, low HDL and high LDL are associated with increased odds of TN and Luminal B BC, respectively, among African women. Future prospective studies can definitively characterize this association and inform clinical approaches targeting HDL as a BC prevention strategy.

5-Fluorouracil Treatment of CT26 Colon Cancer Is Compromised by Combined Therapy with IMMODIN

Due to the physiological complexity of the tumour, a single drug therapeutic strategy may not be sufficient for effective treatment. Emerging evidence suggests that combination strategies may be important to achieve more efficient tumour responses. Different immunomodulators are frequently tested to reverse the situation for the purpose of improving immune response and minimizing chemotherapy side effects. Immodin (IM) represents an attractive alternative to complement chemotherapy, which can be used to enhance the immune system after disturbances resulting from the side effects of chemotherapy. In the presented study, a model of CT26 tumor-bearing mice was used to investigate the effect of single IM or its combination with 5-fluorouracil (5-FU) on colon cancer cells. Our results highlight that the beneficial role of IM claimed in previous studies cannot be generalised to all chemotherapeutic drugs, as 5-FU toxicity was not increased. On the contrary, the chemotherapeutic anti-cancer efficacy of 5-FU was greatly compromised when combined with IM. Indeed, the combined treatment was significantly less effective regarding the tumour growth and animal survival, most probably due to the increased number of tumour-associated macrophages, and increased 5-FU cytotoxic effect related to kidneys and the liver.

Association of SNP rs5069 in APOA1 with Benign Breast Diseases in a Mexican Population

Breast cancer (BCa) is the most common type of cancer affecting women worldwide. Some histological subtypes of benign breast disease (BBD) are considered risk factors for developing BCa. Single nucleotide polymorphisms (SNPs) in the genes encoding apolipoproteins A-I (APOA1) and B (APOB) have been associated with BCa in Tunisian, Chinese, and Taiwanese populations. The objective of this pilot study is to evaluate the possible contribution of APOA1 and APOB polymorphisms to BCa and BBD in the Mexican population. We analyzed the association of 4 SNPs in genes encoding apolipoproteins: rs670 and rs5069 in the APOA1 gene, and rs693 and rs1042031 in the APOB gene, by performing PCR-RFLP with DNA extracted from the biopsy tissue of Mexican women with BCa or BBD and whole blood samples obtained from the general population (GP). Our results showed an association between the CT + TT genotypes of the SNP rs5069 and BBD (p = 0.03201). In the A-T haplotype, the frequency of the SNPs rs670 and rs5069 differed significantly between the BBD group and the GP and BCa groups (p = 0.004111; p = 0.01303). In conclusion, the SNP rs5069 is associated with BBD but not with BCa in the Mexican population.

Association between serum lipids and breast cancer risk in premenopausal women: systematic review and meta-analysis

Objective

Associations between serum lipids and their individual components with premenopausal breast cancer risk are unclear. This meta-analysis summarized the literature on serum lipids and premenopausal breast cancer risk to elucidate their relationship.

Methods

Eligible studies were identified by searching the PubMed, Embase, China National Knowledge Infrastructure, and Wanfang databases until 31 December 2020. Standardized mean difference (SMD) scores with 95% confidence intervals (95%CIs) were used to assess the impact of serum lipids on premenopausal breast cancer risk. The I² statistic was calculated to measure the percentage of heterogeneity, and Egger’s test was performed to measure publication bias.

Results

Thirteen studies were included. The SMD scores of triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) were 12.90 (95%CI: 7.19–18.61) and 31.43 (95%CI: 8.72–54.15), respectively. The SMD scores of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) were not significantly different between the groups. The included studies were highly heterogeneous. There were no publication biases found in TC, LDL-C, or HDL-C analyses, whereas publication bias was present in the TG analysis.

Conclusions

TG and LDL-C were higher in premenopausal breast cancer patients than in women without breast cancer. However, no significant differences were found in TC or HDL-C levels.

Mangifera indica (Mango): A Promising Medicinal Plant for Breast Cancer Therapy and Understanding Its Potential Mechanisms of Action

Globally, breast cancer is the most common cancer type and is one of the most significant causes of deaths in women. To date, multiple clinical interventions have been applied, including surgical resection, radiotherapy, endocrine therapy, targeted therapy and chemotherapy. However, 1) the lack of therapeutic options for metastatic breast cancer, 2) resistance to drug therapy and 3) the lack of more selective therapy for triple-negative breast cancer are some of the major challenges in tackling breast cancer. Given the safe nature of natural products, numerous studies have focused on their anti-cancer potentials. Mangifera indica, commonly known as mango, represents one of the most extensively investigated natural sources. In this review, we provide a comprehensive overview of M. indica extracts (bark, kernel, leaves, peel and pulp) and phytochemicals (mangiferin, norathyriol, gallotannins, gallic acid, pyrogallol, methyl gallate and quercetin) reported for in vitro and in vivo anti-breast cancer activities and their underlying mechanisms based on relevant literature from several scientific databases, including PubMed, Scopus and Google Scholar till date. Overall, the in vitro findings suggest that M. indica extracts and/or phytochemicals inhibit breast cancer cell growth, proliferation, migration and invasion as well as trigger apoptosis and cell cycle arrest. In vivo results demonstrated that there was a reduction in breast tumor xenograft growth. Several potential mechanisms underlying the anti-breast cancer activities have been reported, which include modulation of oxidative status, receptors, signalling pathways, miRNA expression, enzymes and cell cycle regulators. To further explore this medicinal plant against breast cancer, future research directions are addressed. The outcomes of the review revealed that M. indica extracts and their phytochemicals may have potential benefits in the management of breast cancer in women. However, to validate its utility in the creation of innovative and potent therapeutic agents to treat breast cancer, more dedicated research, especially clinical studies are needed to explore the anti-breast cancer potentials of M. indica extracts and their phytochemicals.

Atherosclerosis Impairs Naive CD4 T-Cell Responses via Disruption of Glycolysis

Objective

CD4 T cells are important regulators of atherosclerotic progression. The metabolic profile of CD4 T cells controls their signaling and function, but how atherosclerosis affects T-cell metabolism is unknown. Here, we sought to determine the impact of atherosclerosis on CD4 T-cell metabolism and the contribution of such metabolic alterations to atheroprogression.

Approach and Results

Using PCR arrays, we profiled the expression of metabolism genes in CD4 T cells from atherosclerotic apolipoprotein-E knockout mice fed a Western diet. These cells exhibited dysregulated expression of genes critically involved in glycolysis and fatty acid degradation, compared with those from animals fed a standard laboratory diet. We examined how T-cell metabolism was changed in either Western diet–fed apolipoprotein-E knockout mice or samples from patients with cardiovascular disease by measuring glucose uptake, activation, and proliferation in CD4 T cells. We found that naive CD4 T cells from Western diet–fed apolipoprotein-E knockout mice failed to uptake glucose and displayed impaired proliferation and activation, compared with CD4 T cells from standard laboratory diet–fed animals. Similarly, we observed that naive CD4 T-cell frequencies were reduced in the circulation of human subjects with high cardiovascular disease compared with low cardiovascular disease. Naive T cells from high cardiovascular disease subjects also showed reduced proliferative capacity.

Conclusions

These results highlight the dysfunction that occurs in CD4 T-cell metabolism and immune responses during atherosclerosis. Targeting metabolic pathways within naive CD4 T cells could thus yield novel therapeutic approaches for improving CD4 T-cell responses against atheroprogression.

Dysregulated cholesterol homeostasis results in resistance to ferroptosis increasing tumorigenicity and metastasis in cancer

Hypercholesterolemia and dyslipidemia are associated with an increased risk for many cancer types and with poor outcomes in patients with established disease. Whereas the mechanisms by which this occurs are multifactorial we determine that chronic exposure of cells to 27-hydroxycholesterol (27HC), an abundant circulating cholesterol metabolite, selects for cells that exhibit increased cellular uptake and/or lipid biosynthesis. These cells exhibit substantially increased tumorigenic and metastatic capacity. Notably, the metabolic stress imposed upon cells by the accumulated lipids requires sustained expression of GPX4, a negative regulator of ferroptotic cell death. We show that resistance to ferroptosis is a feature of metastatic cells and further demonstrate that GPX4 knockdown attenuates the enhanced tumorigenic and metastatic activity of 27HC resistant cells. These findings highlight the general importance of ferroptosis in tumor growth and metastasis and suggest that dyslipidemia/hypercholesterolemia impacts cancer pathogenesis by selecting for cells that are resistant to ferroptotic cell death.

Importance of Mevalonate Pathway Lipids on the Growth and Survival of Primary and Metastatic Gastric Carcinoma Cells

Purpose

This preclinical study aims to determine the effect of drugs that alter isoprenoids and cholesterol metabolism in the homeostasis of gastric carcinoma cell lines in the search for new therapeutic targets for stomach cancer.

Materials and Methods

Primary (AGS) and metastatic (NCI-N87) gastric cancer cell lines were treated with simvastatin and terbinafine, two inhibitors of the mevalonate pathway, and avasimibe, an inhibitor of cholesterol esterification. Cell viability and growth were measured as well as cholesterol levels and the expression of the hydroxy methyl-glutaryl CoA reductase (HMGCR) and the LDL receptor (LDLR).

Results

Primary and metastatic gastric carcinoma cells show different sensitivity to drugs that affect isoprenoid synthesis and the metabolism and uptake of cholesterol. Isoprenoids are involved in the growth and viability of both types of cells, but the role of free and esterified cholesterol for metastatic gastric cell survival is not as evident as for primary gastric cancer cells. Differential expression of LDLR due to mevalonate pathway inhibition suggests variations in the regulation of cholesterol uptake between primary and metastatic cancer cells.

Conclusion

These results indicate that at least for primary gastric cancer, statins and avasimibe are promising candidates as potential novel antitumor drugs that target the metabolism of isoprenoids and cholesterol of gastric tumors.

Differential Expression and Prognostic Significance of STARD3 Gene in Breast Carcinoma

StAR related lipid transfer domain containing 3 (STARD3) gene has been reported to be co-amplified with human epidermal growth factor receptor 2 (HER2) in breast carcinoma. STARD3 is necessary for cholesterol transfer and metabolism in tumor cells. The possible role played by STARD3 as a diagnostic and prognostic biomarker was investigated in breast cancer (BC). Data mining was performed using several bioinformatics websites to investigate the correlation of STARD3 with BC and its molecular subtypes, and conventional PCR was used to detect the STARD3 mRNA levels in a panel of BC cell lines. STARD3 was overexpressed in BC more than the other types of cancer. The results also showed that STARD3 expression was significantly associated with HER2⁺ BC tumors and BC cell lines, and low STARD3 mRNA and protein expression levels were observed in estrogen receptor-positive (ER⁺) and triple-negative BC (TNBC) patients. Moreover, high STARD3 expression levels predicted worse overall survival (OS), relapse-free survival (RFS) and disease metastasis-free survival (DMFS) in BC, and HER2⁺ BC. Notably, low expression of STARD3 was associated with poor OS in ER⁺ BC. Our findings suggest that STARD3 may have strong diagnostic and prognostic value for HER2⁺ breast carcinoma.

Revealing the Role of High-Density Lipoprotein in Colorectal Cancer

Colorectal cancer (CRC) is a highly prevalent malignancy with multifactorial etiology, which includes metabolic alterations as contributors to disease development. Studies have shown that lipid status disorders are involved in colorectal carcinogenesis. In line with this, previous studies have also suggested that the serum high-density lipoprotein cholesterol (HDL-C) level decreases in patients with CRC, but more recently, the focus of investigations has shifted toward the exploration of qualitative properties of HDL in this malignancy. Herein, a comprehensive overview of available evidences regarding the putative role of HDL in CRC will be presented. We will analyze existing findings regarding alterations of HDL-C levels but also HDL particle structure and distribution in CRC. In addition, changes in HDL functionality in this malignancy will be discussed. Moreover, we will focus on the genetic regulation of HDL metabolism, as well as the involvement of HDL in disturbances of cholesterol trafficking in CRC. Finally, possible therapeutic implications related to HDL will be presented. Given the available evidence, future studies are needed to resolve all raised issues concerning the suggested protective role of HDL in CRC, its presumed function as a biomarker, and eventual therapeutic approaches based on HDL.

Genetic variants in the cholesterol biosynthesis pathway genes and risk of prostate cancer

Previous studies have found the relationship between cholesterol biosynthesis pathway genes and the risk or prognosis of prostate cancer (PCa), while there is no definite evidence that genetic variants in the cholesterol biosynthesis pathway gene is related to PCa risk. Consequently, we performed this study to explore the associations of single-nucleotide polymorphisms (SNPs) in the cholesterol biosynthesis pathway with PCa risk. We systematically evaluated the association of SNPs in 21 cholesterol biosynthesis pathway genes with the risk of PCa using the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial database using a logistic regression model. Gene expression data of PCa from Gene Expression Omnibus (GEO) datasets and the Cancer Genome Atlas (TCGA) database were applied for mRNA expression analysis. The TCGA database was used to perform expression quantitative trait loci (eQTL) analysis. The interaction between demographic factors and SNPs was analyzed using two-by-four tables. We found T allele of rs67415672 in HMGCS1 is a significant protective allele of PCa [adjusted odds ratio (OR) = 0.90, 95% confidence interval (CI) = 0.83-0.97, P = 4.16 × 10^-3]. Moreover, rs67415672 was an eQTL for HMGCS1 (P = 2.23 × 10^-6). The expression of HMGCS1 significantly decreased in PCa primary tumors than that in normal tissues. These findings indicated that the HMGCS1 rs67415672 might be possible functional susceptibility loci for PCa.

Associations of serum C-peptide and insulin-like growth factor binding proteins-3 with breast cancer deaths

C-peptide is usually considered as a marker of insulin secretion and has no physiological function. This study aimed to assess the association between serum C-peptide level as independent risk factor and breast cancer and explored the possible underlying mechanisms. This was a population-based cohort study. All the data was collected according to a standard protocol. The C-peptide and insulin-like growth factor binding proteins-3(IGFBP-3) concentrations were measured in blood. The breast cancer deaths were confirmed by National Death Index records. Cox proportional hazard regression analysis was conducted to determine the hazard ratio of serum C-peptide level for breast cancer deaths. Analysis of covariance was used to assess the association between serum C-peptide and IGFBP-3 level, and the linear trend was tested by using a linear model. A total of 8,373 women 17 years of age or older were included in the study, and 57 breast cancer deaths were observed over the study period. The result of survival analysis showed that breast cancer deaths increased with increasing levels of serum C-peptide. The hazard ratio was 1.69 (95% confidence interval, 1.17–2.45). The levels of circulating IGFBP-3 were positively associated with changes in serum C-peptide levels and showed a strong linear trend in the covariance analysis. Serum C-peptide level was associated with increased risk of breast cancer death. Our results suggest that the increased risk of breast cancer death can be via a pathway that serum C-peptide level positive associated with the change in serum IGFBP-3 level.

CYP27A1 expression is associated with risk of late lethal estrogen receptor-positive breast cancer in postmenopausal patients

Background

27-Hydroxycholesterol (27HC) stimulates estrogen receptor-positive (ER+) breast cancer (BC) progression. Inhibiting the sterol 27-hydroxylase (CYP27A1) abrogates these growth-promoting effects of 27HC in mice. However, the significance of CYP27A1 expression on BC biology and prognosis is unclear.

Methods

Intratumoral CYP27A1 expression in invasive BC was measured by immunohistochemistry in two Swedish population-based cohorts (n = 645 and n = 813, respectively). Cox proportional hazards models were used to evaluate the association between CYP27A1 expression and prognosis.

Results

CYP27A1 was highly expressed in less than 1/3 of the tumors. High CYP27A1 expression was more frequent among high-grade tumors lacking hormone receptor expression and with larger tumor sizes. Over a median of 12.2 years follow-up in cohort 1, high CYP27A1 expression was associated with impaired survival, specifically after 5 years from diagnosis among all patients [overall survival (OS), HR_adjusted = 1.93, 95%CI = 1.26–2.97, P = 0.003; breast cancer-specific survival (BCSS), HR_adjusted = 2.33, 95%CI = 1.28–4.23, P = 0.006] and among patients ≥ 55 years presenting with ER+ tumors [OS, HR_adjusted = 1.99, 95%CI = 1.24–3.21, P = 0.004; BCSS, HR_adjusted = 2.78, 95%CI = 1.41–5.51, P = 0.003].

Among all patients in cohort 2 (median follow-up of 7.0 years), CYP27A1 expression was significantly associated with shorter OS and RFS in univariable analyses across the full follow-up period. However after adjusting for tumor characteristics and treatments, the association with survival after 5 years from diagnosis was non-significant among all patients [OS, HR_adjusted = 1.08, 95%CI = 0.05–2.35, P = 0.83 and RFS, HR_adjusted = 1.22, 95%CI = 0.68–2.18, P = 0.50] as well as among patients ≥ 55 years presenting with ER+ tumors [OS, HR_adjusted = 0.46 95% CI = 0.11–1.98, P = 0.30 and RFS, HR_adjusted = 0.97 95% CI = 0.44–2.10, P = 0.93].

Conclusion

CYP27A1 demonstrated great potentials as a biomarker of aggressive tumor biology and late lethal disease in postmenopausal patients with ER+ BC. Future studies should investigate if the benefits of prolonged endocrine therapy and cholesterol-lowering medication in BC are modified by CYP27A1 expression.

Systematic investigation of promoter substitutions resulting from somatic intrachromosomal structural alterations in diverse human cancers

One of the ways in which genes can become activated in tumors is by somatic structural genomic rearrangements leading to promoter swapping events, typically in the context of gene fusions that cause a weak promoter to be substituted for a strong promoter. While identifiable by whole genome sequencing, limited availability of this type of data has prohibited comprehensive study of the phenomenon. Here, we leveraged the fact that copy number alterations (CNAs) arise as a result of structural alterations in DNA, and that they may therefore be informative of gene rearrangements, to pinpoint recurrent promoter swapping at a previously intractable scale. CNA data from nearly 9500 human tumors was combined with transcriptomic sequencing data to identify several cases of recurrent activating intrachromosomal promoter substitution events, either involving proper gene fusions or juxtaposition of strong promoters to gene upstream regions. Our computational screen demonstrates that a combination of CNA and expression data can be useful for identifying novel fusion events with potential driver roles in large cancer cohorts.

Atherosclerosis and carcinoma: Two facets of dysfunctional cholesterol homeostasis

Although cholesterol is an essential and necessary component for biological systems; inappropriate accumulation of cholesterol in blood vessels and intracellular territory is also detrimental to living things. On one hand, cholesterol is the acting precursor of many metabolic regulators, a component of the structural veracity and scaffold fluidity of biomembranes, an insulator of electrical transmission in nerves and many more; on the other hand, its deposition in blood vessels induces atherosclerotic plaque and cardiovascular complications with the consequences of heart attack and stroke. It is also an emerging fact that cholesterol is a prelate in the cell nucleus for cell proliferation and any oddity in this venture may be the cause of tumorigenesis. Hence, cholesterol homeostasis is a very crucial element in issues of health management. Cholesterol is now a global target for maintaining quality health, particularly to control the two giants of the present world health tragedy: atherosclerosis and carcinoma, which appear to be the two facets of dysfunctional cholesterol homeostasis.

Pyrvinium Pamoate Induces Death of Triple-Negative Breast Cancer Stem-Like Cells and Reduces Metastases through Effects on Lipid Anabolism

Cancer stem-like cells (CSC) induce aggressive tumor phenotypes such as metastasis formation, which is associated with poor prognosis in triple-negative breast cancer (TNBC). Repurposing of FDA-approved drugs that can eradicate the CSC subcompartment in primary tumors may prevent metastatic disease, thus representing an effective strategy to improve the prognosis of TNBC. Here, we investigated spheroid-forming cells in a metastatic TNBC model. This strategy enabled us to specifically study a population of long-lived tumor cells enriched in CSCs, which show stem-like characteristics and induce metastases. To repurpose FDA-approved drugs potentially toxic for CSCs, we focused on pyrvinium pamoate (PP), an anthelmintic drug with documented anticancer activity in preclinical models. PP induced cytotoxic effects in CSCs and prevented metastasis formation. Mechanistically, the cell killing effects of PP were a result of inhibition of lipid anabolism and, more specifically, the impairment of anabolic flux from glucose to cholesterol and fatty acids. CSCs were strongly dependent upon activation of lipid biosynthetic pathways; activation of these pathways exhibited an unfavorable prognostic value in a cohort of breast cancer patients, where it predicted high probability of metastatic dissemination and tumor relapse. Overall, this work describes a new approach to target aggressive CSCs that may substantially improve clinical outcomes for patients with TNBC, who currently lack effective targeted therapeutic options. SIGNIFICANCE: These findings provide preclinical evidence that a drug repurposing approach to prevent metastatic disease in TNBC exploits lipid anabolism as a metabolic vulnerability against CSCs in primary tumors.

Cholesterol as an Endogenous Ligand of ERRα Promotes ERRα-Mediated Cellular Proliferation and Metabolic Target Gene Expression in Breast Cancer Cells

Breast cancer is the 2nd leading cause of cancer-related death among women. Increased risk of breast cancer has been associated with high dietary cholesterol intake. However, the underlying mechanisms are not known. The nuclear receptor, estrogen-related receptor alpha (ERRα), plays an important role in breast cancer cell metabolism, and its overexpression has been linked to poor survival. Here we identified cholesterol as an endogenous ligand of ERRα by purification from human pregnancy serum using a GST-ERRα affinity column and liquid chromatography-tandem mass spectrometry (LC-MS/MS). We show that cholesterol interacts with ERRα and induces its transcriptional activity in estrogen receptor positive (ER+) and triple negative breast cancer (TNBC) cells. In addition, we show that cholesterol enhances ERRα-PGC-1α interaction, induces ERRα expression itself, augments several metabolic target genes of ERRα, and increases cell proliferation and migration in both ER+ and TNBC cells. Furthermore, the stimulatory effect of cholesterol on metabolic gene expression, cell proliferation, and migration requires the ERRα pathway. These findings provide a mechanistic explanation for the increased breast cancer risk associated with high dietary cholesterol and possibly the pro-survival effect of statins in breast cancer patients, highlighting the clinical relevance of lowering cholesterol levels in breast cancer patients overexpressing ERRα.

Obesity and Cancer: 27-Hydroxycholesterol, the Missing Link

Obesity is currently affecting more than 40% of the Americans, and if it progresses with this rate, soon one out of two Americans will be obese. Obesity is an important risk factor for several disorders including cardiovascular disease, the first cause of death in the United States. Cancer follows as the second deadliest disease, and a link between obesity and cancer has been suggested. However, it is very hard to establish an exact connection between obesity and cancers due to the multifactorial nature of obesity. Hypercholesterolemia is a comorbidity of obesity and also linked to several cancers. Recently a cholesterol metabolite 27-hydroxycholesterol (27HC) was found to be an endogenous selective estrogen receptor modulator (SERM), which opened new doors toward several interesting studies on the role of this molecule in biological disorders. It is speculated that 27HC might be the missing link in the obesity and cancer chain. Here, we explored the effects of 27-hydroxycholesterol on obesity and cancers with a focus on the SERM capacity of 27HC.

Lipid metabolism alteration contributes to and maintains the properties of cancer stem cells

Lipids, the basic components of the cell membrane, execute fundamental roles in almost all the cell activities including cell-cell recognition, signalling transduction and energy supplies. Lipid metabolism is elementary for life sustentation that balances activity between synthesis and degradation. An accumulating amount of data has indicated abnormal lipid metabolism in cancer stem cells (CSCs), and that the alteration of lipid metabolism exerts a great impact on CSCs' properties such as the capability of self-renewal, differentiation, invasion, metastasis, and drug sensitivity and resistance. CSCs' formation and maintenance cannot do without the regulation of fatty acids and cholesterol. In normal cells and embryonic development, fatty acids and cholesterol metabolism are regulated by some important signalling pathways (such as Hedgehog, Notch, Wnt signalling pathways); these signalling pathways also play crucial roles in initiating and/or maintaining CSCs' properties, and such signalling is shown to be commonly modulated by the abnormal lipid metabolism in CSCs; on the other hand, the altered lipid metabolism in turn modifies the cell signalling and generates additional impacts on CSCs. Metabolic rewiring is considered as an ideal hallmark of CSCs, and metabolic alterations would be promising therapeutic targets of CSCs for aggressive tumors. In this review, we summarize the most updated findings of lipid metabolic abnormalities in CSCs and prospect the potential applications of targeting lipid metabolism for anticancer treatment.

Lipid rafts as signaling hubs in cancer cell survival/death and invasion: implications in tumor progression and therapy: Thematic Review Series: Biology of Lipid Rafts

Cholesterol/sphingolipid-rich membrane domains, known as lipid rafts or membrane rafts, play a critical role in the compartmentalization of signaling pathways. Physical segregation of proteins in lipid rafts may modulate the accessibility of proteins to regulatory or effector molecules. Thus, lipid rafts serve as sorting platforms and hubs for signal transduction proteins. Cancer cells contain higher levels of intracellular cholesterol and lipid rafts than their normal non-tumorigenic counterparts. Many signal transduction processes involved in cancer development (insulin-like growth factor system and phosphatidylinositol 3-kinase-AKT) and metastasis [cluster of differentiation (CD)44] are dependent on or modulated by lipid rafts. Additional proteins playing an important role in several malignant cancers (e.g., transmembrane glycoprotein mucin 1) are also being detected in association with lipid rafts, suggesting a major role of lipid rafts in tumor progression. Conversely, lipid rafts also serve as scaffolds for the recruitment and clustering of Fas/CD95 death receptors and downstream signaling molecules leading to cell death-promoting raft platforms. The partition of death receptors and downstream signaling molecules in aggregated lipid rafts has led to the formation of the so-called cluster of apoptotic signaling molecule-enriched rafts, or CASMER, which leads to apoptosis amplification and can be pharmacologically modulated. These death-promoting rafts can be viewed as a linchpin from which apoptotic signals are launched. In this review, we discuss the involvement of lipid rafts in major signaling processes in cancer cells, including cell survival, cell death, and metastasis, and we consider the potential of lipid raft modulation as a promising target in cancer therapy.

Cholesterol: A Prelate in Cell Nucleus and its Serendipity

Cholesterol is a chameleon bio-molecule in cellular multiplex. It acts as a prelate in almost every cellular compartment with its site specific characteristics viz. regulation of structural veracity and scaffold fluidity of bio-membranes, insulation of electrical transmission in nerves, controlling of genes by making steroid endocrines, acting as precursors of metabolic regulators and many more with its emerging prophecy in the cell nucleus to drive new cell formation. Besides the crucial legacy in cellular functionality, cholesterol is ostracized as a member of LDL particle, which has been proved responsible to clog blood vessels. LDL particles get deposited in the blood vessels because of their poor clearance owing to the non-functioning LDL receptor on the vessel wall and surrounding tissues. Blocking of blood vessel promotes heart attack and stroke. On the other hand, cholesterol has been targeted as pro-cancerous molecule. At this phase again cholesterol is biphasic. Although cholesterol is essential to construct nuclear membrane and its lipid-rafts; in cancer tumour cells, cholesterol is not under the control of intracellular feedback regulation and gets accumulated within cell nucleus by crossing nuclear membrane and promoting cell proliferation. In precancerous stage, the immune cells also die because of the lack of requisite concentration of intracellular and intranuclear cholesterol pool. The existence of cholesterol within the cell nucleus has been found in the nuclear membrane, epichromosomal location and nucleoplasm. The existence of cholesterol in the microdomain of nuclear raft has been reported to be linked with gene transcription, cell proliferation and apoptosis. Hydrolysis of cholesterol esters in chromosomal domain is linked with new cell generation. Apparently, Cholesterol is now a prelate in cell nucleus too ------ A serendipity in cellular haven.

Role of Lipoproteins in the Microenvironment of Hormone-Dependent Cancers

The tumor microenvironment (TME) is an attractive target to develop novel strategies for hormone-dependent cancers. Several molecules in the TME can favor tumor development and progression, including lipoproteins. Lipoproteins are taken up by cancer cells, providing them with cholesterol and fatty acids. Cholesterol regulates cell signaling and it is converted into a series of bioactive metabolites, including hormones. The conflicting results of epidemiological and interventional studies suggest that the local availability of lipoproteins in the TME is more relevant for cancer biology than their circulating levels. Thus, reducing lipoprotein uptake and stimulating cell cholesterol efflux to high-density lipoproteins (HDLs) can represent a novel adjuvant strategy for cancer management. HDL-like particles can also act as drug delivery systems for tumor targeting.

Cardio-Oncology: Vascular and Metabolic Perspectives: A Scientific Statement From the American Heart Association

Cardio-oncology has organically developed as a new discipline within cardiovascular medicine as a result of the cardiac and vascular adverse sequelae of the major advances in cancer treatment. Patients with cancer and cancer survivors are at increased risk of vascular disease for a number of reasons. First, many new cancer therapies, including several targeted therapies, are associated with vascular and metabolic complications. Second, cancer itself serves as a risk factor for vascular disease, especially by increasing the risk for thromboembolic events. Finally, recent data suggest that common modifiable and genetic risk factors predispose to both malignancies and cardiovascular disease. Vascular complications in patients with cancer represent a new challenge for the clinician and a new frontier for research and investigation. Indeed, vascular sequelae of novel targeted therapies may provide insights into vascular signaling in humans. Clinically, emerging challenges are best addressed by a multidisciplinary approach in which cardiovascular medicine specialists and vascular biologists work closely with oncologists in the care of patients with cancer and cancer survivors. This novel approach realizes the goal of providing superior care through the creation of cardio-oncology consultative services and the training of a new generation of cardiovascular specialists with a broad understanding of cancer treatments.

Cardiovascular Disease Risk in Survivors of Breast Cancer

PURPOSE OF REVIEW

Early detection and improved treatment in breast cancer have resulted in an increased number of survivors. Cardiovascular disease now remains an important cause for morbidity and mortality in this population. There is a growing gap in the knowledge about the optimal long-term cardiovascular management of this population.

FINDINGS

Breast cancer and cardiovascular disease share a number of common risk factors. Different breast cancer treatment modalities, including anthracyclines, radiation, and hormonal therapy, can act in synergy with preexisting and/or new cardiovascular risk factors to result in significant cardiovascular disease. We summarize the recent evidence about cardiovascular effects of breast cancer therapy and recommendations for their diagnosis and management during the cancer treatment continuum into survivorship. We also present current research initiatives and how they inform clinical care.

Expression of LXR‑β, ABCA1 and ABCG1 in human triple‑negative breast cancer tissues

Previous studies have reported that liver X receptor (LXR), ATP-binding cassette sub-family G number 1 (ABCG1) and ATP-binding cassette transporter number 1 (ABCA1), which are associated with cholesterol metabolism, may be associated with the development and progression of breast cancer. The expression levels of LXR-β, ABCA1 and ABCG1 in triple-negative breast cancer (TNBC) tissues and in non-cancerous mammary tissues were observed by immunohistochemistry, quantum dot-based immunohistochemistry, western blot analysis and reverse transcription-quantitative polymerase chain reaction. The present study identified that the expression of ABCA1 in TNBC tissues was higher than that in non-cancerous mammary tissues. A high expression of ABCA1 in the TNBC tissues was significantly associated with the histological grade. However, no significant differences were identified between the expression levels of LXR-β and ABCG1 in the TNBC tissues compared with the non-cancerous mammary tissues. Therefore, the findings of this study suggest that ABCA1 is a specific marker for TNBC.

Warburg Effect Inversion: Adiposity shifts central primary metabolism in MCF-7 breast cancer cells

AIMS

Obesity is a complex health disorder and a trigger to many diseases like Diabetes mellitus (DM) and breast cancer (BrCa), both leading causes of morbidity and mortality worldwide. Also evidence demonstrates that abnormal glucose metabolism termed 'the Warburg effect' in cancer cell is closely associated with malignant phenotypes and promote the aggressiveness of several types of cancer, including BrCa. In this study, we evaluated the breast cancer cell metabolism in normoglycemia, hyperglycemia and in an obesity condition in order to clarify the potential underlined mechanisms that link these disorders.

MATERIALS AND METHODS

MCF-7 cells were exposed to low and high glucose levels, the latter either in the presence of 3T3-L1 adipocyte conditioned medium (CM), thus mimicking the adiposity observed in obese patients. Cell viability, migration, proliferation, cytotoxicity and cell death assays were performed under the different culture conditions. Hormonal and lipid profile were also characterized by biochemical assays and primary metabolism was determined by Nuclear Magnetic Resonance (NMR)-based metabolomics.

RESULTS

Our results show an increased aggressiveness in the condition mimicking diabetogenic obesity with an altered energy/lipid metabolism. Interestingly in the experimental obesity-mimicking status, lipids and amino acids were expended while glucose was produced by tumor cells from lactate. These findings reveal a shift on tumor cells metabolism that is opposite to 'the Warburg effect'.

CONCLUSIONS

Overall, this experimentally obesity-mimicking condition not only revealed an increased tumor proliferation and aggressiveness but also disclosed a new mechanism of cancer metabolism, the 'Warburg Effect Inversion'.

Disrupting cholesterol esterification by bitter melon suppresses triple-negative breast cancer cell growth

Triple negative breast cancer (TNBC) is aggressive with a worse prognosis. We have recently shown that bitter melon extract (BME) treatment was more effective in inhibition of TNBC tumor growth in mouse models as compared to ER positive breast tumor growth. Aberrant dysregulation of lipid metabolism is associated with breast cancer progression, however, anti-cancer mechanism of BME linking lipid metabolism in breast cancer growth remains unexplored. Here, we observed that accumulation of esterified cholesterol was reduced in BME treated TNBC cell lines as compared to control cells. We next evaluated expression levels of acyl-CoA: cholesterol acyltransferase 1 (ACAT-1) in TNBC cells treated with BME. Our results demonstrated that BME treatment inhibited ACAT-1 expression in TNBC cells. Subsequently, we found that sterol regulatory element-binding proteins-1 and -2, and FASN was significantly reduced in BME treated TNBC cell lines. Low-density lipoprotein receptor was also downregulated in BME treated TNBC cells as compared to control cells. We further demonstrated that BME feeding reduced tumor growth in TNBC mammospheres implanted into NSG mice, and inhibits ACAT-1 expression. To our knowledge, this is the first report demonstrating BME suppresses TNBC cell growth through ACAT-1 inhibition, and have potential for additional therapeutic regimen against human breast cancer.

High-density lipoprotein functionality and breast cancer: A potential therapeutic target

Breast cancer is a major cause of death globally, and particularly in developed countries. Breast cancer is influenced by cholesterol membrane content, by affecting the signaling pathways modulating cell growth, adherence, and migration. Furthermore, steroid hormones are derived from cholesterol and these play a key role in the pathogenesis of breast cancer. Although most findings have reported an inverse association between serum high-density lipoprotein (HDL)-cholesterol level and the risk of breast cancer, there have been some reports of the opposite, and the association therefore remains unclear. HDL is principally known for participating in reverse cholesterol transport and has an inverse relationship with the cardiovascular risk. HDL is heterogeneous, with particles varying in composition, size, and structure, which can be altered under different circumstances, such as inflammation, aging, and certain diseases. It has also been proposed that HDL functionality might have a bearing on the breast cancer. Owing to the potential role of cholesterol in cancer, its reduction using statins, and particularly as an adjuvant during chemotherapy may be useful in the anticancer treatment, and may also be related to the decline in cancer mortality. Reconstituted HDLs have the ability to release chemotherapeutic drugs inside the cell. As a consequence, this may be a novel way to improve therapeutic targeting for the breast cancer on the basis of detrimental impacts of oxidized HDL on cancer development.

The contribution of cholesterol and epigenetic changes to the pathophysiology of breast cancer

Breast cancer​ is one of the most commonly diagnosed cancers in women. Accumulating evidence suggests that cholesterol plays an important role in the development of breast cancer. Even though the mechanistic link between these two factors is not well understood, one possibility is that dysregulated cholesterol metabolism may affect lipid raft and membrane fluidity and can promote tumor development. Current studies have shown oxysterol 27-hydroxycholesterol (27-HC) as a critical regulator of cholesterol and breast cancer pathogenesis. This is supported by the significantly higher expression of CYP27A1 (cytochrome P450, family 27, subfamily A, polypeptide 1) in breast cancers. This enzyme is responsible for 27-HC synthesis from cholesterol. It has been shown that 27-HC can not only increase the proliferation of estrogen receptor (ER)-positive breast cancer cells but also stimulate tumor growth and metastasis in several breast cancer models. This phenomenon is surprising since 27-HC and other oxysterols generally reduce intracellular cholesterol levels by activating the liver X receptors (LXRs). Resolving this paradox will elucidate molecular pathways by which cholesterol, ER, and LXR are connected to breast cancer. These findings will also provide the rationale for evaluating pharmaceutical approaches that manipulate cholesterol or 27-HC synthesis in order to mitigate the impact of cholesterol on breast cancer pathophysiology. In addition to cholesterol, epigenetic changes including non-coding RNAs, and microRNAs, DNA methylation, and histone modifications, have all been shown to control tumorigenesis. The purpose of this review is to discuss the link between altered cholesterol metabolism and epigenetic modification during breast cancer progression.

A Mendelian randomization study of the effects of blood lipids on breast cancer risk

Observational studies have reported inconsistent associations between circulating lipids and breast cancer risk. Using results from >400,000 participants in two-sample Mendelian randomization, we show that genetically raised LDL-cholesterol is associated with higher risk of breast cancer (odds ratio, OR, per standard deviation, 1.09, 95% confidence interval, 1.02-1.18, P = 0.020) and estrogen receptor (ER)-positive breast cancer (OR 1.14 [1.05-1.24] P = 0.004). Genetically raised HDL-cholesterol is associated with higher risk of ER-positive breast cancer (OR 1.13 [1.01-1.26] P = 0.037). HDL-cholesterol-raising variants in the gene encoding the target of CETP inhibitors are associated with higher risk of breast cancer (OR 1.07 [1.03-1.11] P = 0.001) and ER-positive breast cancer (OR 1.08 [1.03-1.13] P = 0.001). LDL-cholesterol-lowering variants mimicking PCSK9 inhibitors are associated (P = 0.014) with lower breast cancer risk. We find no effects related to the statin and ezetimibe target genes. The possible risk-promoting effects of raised LDL-cholesterol and CETP-mediated raised HDL-cholesterol have implications for breast cancer prevention and clinical trials.

The significance of cholesterol and its metabolite, 27-hydroxycholesterol in breast cancer

Although significant advances in the treatment of breast cancer have been made, in particular in the use of endocrine therapy, de novo and aquired resistance to therapy, and metastatic recurrence continue to be major clinical problems. Given the high prevalence of breast cancer, new life-style or chemotherapeutic approaches are required. In this regard, cholesterol has emerged as a risk factor for the onset of breast cancer, and elevated cholesterol is associated with a poor prognosis. While treatment with cholesterol lowering medication is not associated with breast cancer risk, it does appear to be protective against recurrence. Importantly, the cholesterol axis represents a potential target for both life-style and pharmacological intervention. This review will outline the clinical and preclinical data supporting a role for cholesterol in breast cancer pathophysiology. Specific focus is given to 27-hydroxycholesterol (27-OHC; (3β,25R)-Cholest-5-ene-3,26-diol)), a primary metabolite of cholesterol that has recently been defined as an endogenous Selective Estrogen Receptor Modulator. Future perspectives and directions are discussed.

Actinidia chinensis Planch root extract inhibits cholesterol metabolism in hepatocellular carcinoma through upregulation of PCSK9

Actinidia chinensis Planch root extract (acRoots) is a traditional Chinese medicine with anti-tumor efficacy. To investigate the mechanisms responsible for this activity, we examined the effects of acRoots on cholesterol metabolism in hepatocellular carcinoma (HCC). mRNA chip analysis was used to identify the metabolic genes regulated by acRoots. The effects of acRoots on cholesterol synthesis and uptake were evaluated by measuring intracellular cholesterol levels and 3,3′-dioctadecylindocarbocyanine-labeled low-density lipoprotein (Dil-LDL) uptake. Expression of metabolic genes was analyzed using quantitative reverse transcription PCR, western blotting, and flow cytometry. acRoots reduced the viability of LM3 and HepG2 cells at 5 mg/mL and HL-7702 cells at 30 mg/mL. Gene expression profiling revealed that treatment with acRoots altered expression of genes involved in immune responses, inflammation, proliferation, cell cycle control, and metabolism. We also confirmed that acRoots enhances expression of PCSK9, which is important for cholesterol metabolism. This resulted in decreased LDL receptor expression, inhibition of LDL uptake by LM3 cells, decreased total intracellular cholesterol, and reduced proliferation. These effects were promoted by PCSK9 overexpression and rescued by PCSK9 knockdown. Our data demonstrate that acRoots is a novel anti-tumor agent that inhibits cholesterol metabolism though a PCSK9-mediated signaling pathway.

Dietary Factors and Female Breast Cancer Risk: A Prospective Cohort Study

Breast cancer is the leading cause of cancer in females and has become a major global health priority. This prospective cohort study investigated the association of dietary factors, including food items and dietary habits, with the risk of breast cancer in Korean women. Study participants were women aged 30 years or older, recruited from the National Cancer Center in South Korea between August 2002 and May 2007. They were followed until December 2014 using the Korea Central Cancer Registry to identify breast cancer cases. Among 5046 non-pre-diagnosed cancer participants, 72 breast cancer cases were prospectively identified. Participants with breast cancer had a significantly higher educational level (college or higher: 58.3% vs. 39.5%, p = 0.01), were more likely to have ever smoked (22.2% vs. 7.8%, p < 0.001), and were more likely to have a history of benign breast tumors (10% vs. 4%, p = 0.02) than non-cases. Consumption of grilled meat conferred a significantly higher risk of breast cancer in all women (hazard ratio (HR) 1.77, 95% confidence interval (CI) 1.09–2.85) and in postmenopausal women (HR 3.06, 95% CI 1.31–7.15). High-cholesterol food intake was associated with a higher risk in all women (HR 1.69, 95% CI 1.01–2.82). Irregular meal intake was associated with an elevated risk in all women (HR 2.19, 95% CI 1.20–3.98, p for trend = 0.01) and in premenopausal women (HR 2.35, 95% CI 1.13–4.91, p for trend = 0.03). Our findings suggest that grilled meat and high-cholesterol food intake and irregular eating habits may be associated with a higher risk of breast cancer. Further studies with longer follow-up periods that include information on portion size, hormone receptor status, carcinogen levels in grilled meat, and a classification of foods by source are required.