LDL-cholesterol signaling induces breast cancer proliferation and invasion

The association between oxidized low-density lipoprotein and cancer: An emerging targeted therapeutic approach?

Lipids play an important role in varying vital cellular processes including cell growth and division. Elevated levels of low-density lipoprotein (LDL) and oxidized-LDL (ox-LDL), and overexpression of the corresponding receptors including LDL receptor (LDLR), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), and cluster of differentiation 36 (CD36), have shown strong correlations with different facets of carcinogenesis including proliferation, invasion, and angiogenesis. Furthermore, a high serum level of LOX-1 is considered as a poor prognostic factor in many types of cancer including colorectal cancer. Ox-LDL could contribute to cancer progression and metastasis through endothelial-to-mesenchymal transition (EMT) and autophagy. Thus, many studies have shed light on the significant role of ox-LDL as a potential therapeutic target for cancer therapy. In various repurposing approaches, anti-dyslipidemia agents, phytochemicals, autophagy modulators as well as recently developed ldl-like nanoparticles have been investigated as potential tumor therapeutic agents by targeting oxidized-LDL/LOX-1 pathways. Herein, we reviewed the role of oxidized-LDL and LOX-1 in cancer progression, invasion, metastasis, and also cancer-associated angiogenesis. Moreover, we addressed therapeutic utility of several compounds that proved to be capable of targeting the metabolic moieties in cancer. This review provides insights on the potential impact of targeting LDL and ox-LDL in cancer therapy and their future biomedical implementations.

A novel signature incorporating genes related to lipid metabolism and immune for prognostic and functional prediction of breast cancer

PURPOSE

Breast cancer prognosis and functioning have not been thoroughly examined in relation to immunological and lipid metabolism. However, there is a lack of prognostic and functional analyses of the relationship between lipid metabolism and immunity in breast cancer.

METHODS

DEGs in breast cancer were obtained from UCSC database, and lipid metabolism and immune-related genes were obtained from GSEA and Immune databases. A predictive signature was constructed using univariate Cox and LASSO regression on lipid metabolism and immune-related DEGs. The signature's prognostic significance was assessed using Kaplan-Meier, time-dependent ROC, and risk factor survival scores. Survival prognosis, therapeutic relevance, and functional enrichment were used to mine model gene biology. We selected IL18, which has never been reported in breast cancer before, in the signature to learn more about its function, potential to predict outcome, and immune system role. RT-PCR was performed to verify the true expression level of IL18.

RESULTS

A total of 136 DEGs associated with breast cancer responses to both immunity and lipid metabolism. Nine key genes (CALR, CCL5, CEPT, FTT3, CXCL13, FLT3, IL12B, IL18, and IL24, p < 1.6e-2) of breast cancer were identified, and a prognostic was successfully constructed with a good predictive ability. IL18 in the model also had good clinical prognostic guidance value and immune regulation and therapeutic potential. Furthermore, the expression of IL18 was higher than that in paracancerous tissue.

CONCLUSIONS

A unique predictive signature model could effectively predict the prognosis of breast cancer, which can not only achieve survival prediction, but also screen out key genes with important functional mechanisms to guide clinical drug experiments.

Cholesteryl ester transfer protein knock-down in conjunction with a cholesterol-depleting agent decreases tamoxifen resistance in breast cancer cells

The cholesterogenic phenotype, encompassing de novo biosynthesis and accumulation of cholesterol, aids cancer cell proliferation and survival. Previously, the role of cholesteryl ester (CE) transfer protein (CETP) has been implicated in breast cancer aggressiveness, but the molecular basis of this observation is not clearly understood, which this study aims to elucidate. CETP knock-down resulted in a >50% decrease in cell proliferation in both 'estrogen receptor-positive' (ER+; Michigan Cancer Foundation-7 (MCF7) breast cancer cells) and 'triple-negative' breast cancer (TNBC; MDA-MB-231) cell lines. Intriguingly, the abrogation of CETP together with the combination treatment of tamoxifen (5 μM) and acetyl plumbagin (a cholesterol-depleting agent) (5 μM) resulted in twofold to threefold increase in apoptosis in both cell lines. CETP knockdown also showed decreased intracellular CE levels, lipid raft and lipid droplets in both cell lines. In addition, RT2 Profiler PCR array (Qiagen, Germany)-based gene expression analysis revealed an overall downregulation of genes associated in cholesterol biosynthesis, lipid signalling and drug resistance in MCF7 cells post-CETP knock-down. On the contrary, resistance in MDA-MB-231 cells was reduced through increased expression in cholesterol efflux genes and the expression of targetable surface receptors by endocrine therapy. The pilot xenograft mice study substantiated CETP's role as a cancer survival gene as knock-down of CETP stunted the growth of TNBC tumour by 86%. The principal findings of this study potentiate CETP as a driver in breast cancer growth and aggressiveness and thus targeting CETP could limit drug resistance via the reduction in cholesterol accumulation in breast cancer cells, thereby reducing cancer aggressiveness.

Niclosamide: A career builder

My contribution to honoring Professor Kinam Park celebrates and resonates with his scholarly career in drug delivery, his commitment to encouraging the next generation(s), and his efforts to keep us focused on clinically effective formulations. To do this I take as my example, niclosamide, a small molecule protonophore that, uniquely, can "target" all cell membranes, both plasma and organelle. As such, it acts upstream of many cell pathways and so has the potential to affect many of the essential events that a cell, and particularly a diseased cell or other entities like a virus, use to stay alive and prosper. Literature shows that it has so far been discovered to positively influence (at least): cancer, bacterial and viral infection, metabolic diseases such as Type II diabetes, NASH and NAFLD, artery constriction, endometriosis, neuropathic pain, rheumatoid arthritis, sclerodermatous graft-versus-host disease, systemic sclerosis, Parkinson's, and COPD. With such a fundamental action and broad-spectrum activity, I believe that studying niclosamide in all its manifestations, discovering if and to what extent it can contribute positively to disease control (and also where it can't), formulating it as effective therapeutics, and testing them in preclinical and clinical trials is a career builder for our next generation(s). The article is divided into two parts: Part I introduces niclosamide and other proton shunts mainly in cancer and viral infections and reviews an exponentially growing literature with some concepts and physicochemical properties that lead to its proton shunt mechanism. Part II focuses on repurposing by reformulation of niclosamide. I give two examples of "carrier-free formulations", - one for cancer (as a prodrug therapeutic of niclosamide stearate for i.v. and other administration routes, exemplified by our recent work on Osteosarcoma in mice and canine patients), and the other as a niclosamide solution formulation (that could provide the basis for a preventative nasal spray and early treatment option for COVID19 and other respiratory virus infections). My goal is to excite and enthuse, encourage, and motivate all involved in the drug development and testing process in academia, institutes, and industry, to learn more about this interesting molecule and others like it. To enable such endeavors, I give many proposed ideas throughout the document, that have been stimulated and inspired by gaps in the literature, urgent needs in disease, and new studies arising from our own work. The hope is that, by reading through this document and studying the suggested topics and references, the drug delivery and development community will continue our lineage and benefit from our legacy to achieve niclosamide's potential as an effective contributor to the treatment and control of many diseases and conditions.

A high-cholesterol diet promotes the intravasation of breast tumor cells through an LDL-LDLR axis

Most metastases in breast cancer occur via the dissemination of tumor cells through the bloodstream. How tumor cells enter the blood (intravasation) is, however, a poorly understood mechanism at the cellular and molecular levels. Particularly uncharacterized is how intravasation is affected by systemic nutrients. High levels of systemic LDL-cholesterol have been shown to contribute to breast cancer progression and metastasis in various models, but the cellular and molecular mechanisms involved are still undisclosed. Here we show that a high- cholesterol diet promotes intravasation in two mouse models of breast cancer and that this could be reverted by blocking LDL binding to LDLR in tumor cells. Moreover, we show that LDL promotes vascular invasion in vitro and the intercalation of tumor cells with endothelial cells, a phenotypic change resembling vascular mimicry (VM). At the molecular level, LDL increases the expression of SERPINE2, previously shown to be required for both VM and intravasation. Overall, our manuscript unravels novel mechanisms by which systemic hypercholesterolemia may affect the onset of metastatic breast cancer by favouring phenotypic changes in breast cancer cells and increasing intravasation.

Profiling of serum metabolome of breast cancer: multi-cancer features discriminate between healthy women and patients with breast cancer

Introduction

The progression of solid cancers is manifested at the systemic level as molecular changes in the metabolome of body fluids, an emerging source of cancer biomarkers.

Methods

We analyzed quantitatively the serum metabolite profile using high-resolution mass spectrometry. Metabolic profiles were compared between breast cancer patients (n=112) and two groups of healthy women (from Poland and Norway; n=95 and n=112, respectively) with similar age distributions.

Results

Despite differences between both cohorts of controls, a set of 43 metabolites and lipids uniformly discriminated against breast cancer patients and healthy women. Moreover, smaller groups of female patients with other types of solid cancers (colorectal, head and neck, and lung cancers) were analyzed, which revealed a set of 42 metabolites and lipids that uniformly differentiated all three cancer types from both cohorts of healthy women. A common part of both sets, which could be called a multi-cancer signature, contained 23 compounds, which included reduced levels of a few amino acids (alanine, aspartate, glutamine, histidine, phenylalanine, and leucine/isoleucine), lysophosphatidylcholines (exemplified by LPC(18:0)), and diglycerides. Interestingly, a reduced concentration of the most abundant cholesteryl ester (CE(18:2)) typical for other cancers was the least significant in the serum of breast cancer patients. Components present in a multi-cancer signature enabled the establishment of a well-performing breast cancer classifier, which predicted cancer with a very high precision in independent groups of women (AUC>0.95).

Discussion

In conclusion, metabolites critical for discriminating breast cancer patients from controls included components of hypothetical multi-cancer signature, which indicated wider potential applicability of a general serum metabolome cancer biomarker.

Polydatin ameliorates low-density lipoprotein cholesterol and lipid metabolism by downregulating proprotein convertase subtilisin/kexin type 9 (PCSK9) in triple-negative breast cancer with hyperlipidemia

To investigate polydatin's effects on low-density lipoprotein cholesterol (LDL-C) and lipid metabolism in mice with triple-negative breast cancer (TNBC) and hyperlipidemia, as well as the underlying mechanism of proprotein convertase subtilisin/kexin type 9 (PCSK9). In vivo, we designed two animal models, namely breast pad in situ inoculation of TNBC model and TNBC with lung metastatic were inoculated with the caudal vein model. Mice were administered a high-fat diet. Upon the completion of the experiment, plasma triglycerides (TG), total plasma cholesterol (TC), plasma LDL-C, and plasma high-density lipoprotein cholesterol (HDL-C) were measured. ELISA was employed to measure PCSK9 and the low-density lipoprotein receptor (LDLR). The morphological alterations were observed using Oil-red O staining. Immunohistochemical labeling was used to determine the expression of PCSK9 and LDLR in mouse breast cancer (BC) tissues. MTT, wound healing assay, and the transwell migration and invasion test were conducted to examine co-cultured adipocytes' effects on the growth, invasion, and migration of BC cells. In the 4T1-luc cell model injected in situ into the breast pad and 4T1-luc cell model injected into the tail vein, we observed that a high-fat diet promoted the proliferation and lung metastasis of BC cells, whereas polydatin suppressed the proliferation and lung metastasis of BC cells. Co-culture of BC cells with adipocytes enhanced the proliferation, invasion, and metastasis, while polydatin intervention inhibited the growth, invasion, and metastasis. After treatment with polydatin, serum lipid levels decreased, PCSK9 decreased, LDLR increased, and LDL-C decreased in mouse BC, liver, and lung tissues. After polydatin treatment, PCSK9 decreased, LDLR increased, and LDL-C decreased in an in vitro co-culture system of BC cells and adipocytes. After transfection of siRNA PCSK9 in the co-culture system, the LDLR increased more significantly, and the LDL-C decreased more significantly. After transfection of LV-PCSK9, PCSK9 decreased, LDLR increased, and LDL-C decreased. We concluded that polydatin inhibited breast tumor proliferation and distant lung metastasis in mice promoted by a high lipid environment. By suppressing PCSK9, polydatin alters the lipid profile of hyperlipidemic TNBC mice and prevents distant metastases. Our findings provide credence to the established practice of using polydatin in treating TNBC combined with hyperlipidemia.

Examining the expression of low-density lipoprotein receptor (LDLR) and low-density lipoprotein receptor-related protein 6 (LRP6) genes in breast cancer cell lines

Cholesterol and the Wnt/β-catenin pathway have an effective role in the proliferation, survival, drug resistance, immune exhaustion, and metastasis of all types of cancer cells. Considering the role of LDLR and LRP6 proteins in cholesterol uptake by cells and activation of Wnt/β-catenin pathway, this study aims to examine the gene expression of LDLR and LRP6 in cell lines of breast cancer. Human breast cancer cell lines MCF7, MD468 and SKBR3 were cultured in suitable conditions and after extracting total RNA from them, real-Time PCR was used to measure the levels of gene expression for LDLR and LRP6. Our results showed that the expression of LDLR and LRP6 genes is significantly increased in MCF7 and MD468 cells compared to SKBR3 cells. These results suggest that LRP6 and LDLR can be considered as a therapeutic target in tumors that have a genetic profile similar to MCF7 and MD468 cells.

MiR-4646-5p Acts as a Tumor-Suppressive Factor in Triple Negative Breast Cancer and Targets the Cholesterol Transport Protein GRAMD1B

MicroRNAs (miRNAs) are crucial post-transcriptional regulators of gene expression, and their deregulation contributes to many aspects of cancer development and progression. Thus, miRNAs provide insight into oncogenic mechanisms and represent promising targets for new therapeutic approaches. A type of cancer that is still in urgent need of improved treatment options is triple negative breast cancer (TNBC). Therefore, we aimed to characterize a novel miRNA with a potential role in TNBC. Based on a previous study, we selected miR-4646-5p, a miRNA with a still unknown function in breast cancer. We discovered that higher expression of miR-4646-5p in TNBC patients is associated with better survival. In vitro assays showed that miR-4646-5p overexpression reduces growth, proliferation, and migration of TNBC cell lines, whereas inhibition had the opposite effect. Furthermore, we found that miR-4646-5p inhibits the tube formation ability of endothelial cells, which may indicate anti-angiogenic properties. By whole transcriptome analysis, we not only observed that miR-4646-5p downregulates many oncogenic factors, like tumor-promoting cytokines and migration- and invasion-related genes, but were also able to identify a direct target, the GRAM domain-containing protein 1B (GRAMD1B). GRAMD1B is involved in cellular cholesterol transport and its knockdown phenocopied the growth-reducing effects of miR-4646-5p. We thus conclude that GRAMD1B may partly contribute to the diverse tumor-suppressive effects of miR-4646-5p in TNBC.

Targeting cholesterol metabolism in Cancer: From molecular mechanisms to therapeutic implications

Cholesterol is an essential component of cell membranes and helps to maintain their structure and function. Abnormal cholesterol metabolism has been linked to the development and progression of tumors. Changes in cholesterol metabolism triggered by internal or external stimuli can promote tumor growth. During metastasis, tumor cells require large amounts of cholesterol to support their growth and colonization of new organs. Recent research has shown that cholesterol metabolism is reprogrammed during tumor development, and this can also affect the anti-tumor activity of immune cells in the surrounding environment. However, identifying the specific targets in cholesterol metabolism that regulate cancer progression and the tumor microenvironment is still a challenge. Additionally, exploring the potential of combining statin drugs with other therapies for different types of cancer could be a worthwhile avenue for future drug development. In this review, we focus on the molecular mechanisms of cholesterol and its derivatives in cell metabolism and the tumor microenvironment, and discuss specific targets and relevant therapeutic agents that inhibit aspects of cholesterol homeostasis.

Low-density lipoprotein receptor promotes crosstalk between cell stemness and tumor immune microenvironment in breast cancer: a large data-based multi-omics study

BACKGROUND

Tumor cells with stemness in breast cancer might facilitate the immune microenvironment's suppression process and led to anti-tumor immune effects. The primary objective of this study was to identify potential targets to disrupt the communication between cancer cell stemness and the immune microenvironment.

METHODS

In this study, we initially isolated tumor cells with varying degrees of stemness using a spheroid formation assay. Subsequently, we employed RNA-seq and proteomic analyses to identify genes associated with stemness through gene trend analysis. These stemness-related genes were then subjected to pan-cancer analysis to elucidate their functional roles in a broader spectrum of cancer types. RNA-seq data of 3132 patients with breast cancer with clinical data were obtained from public databases. Using the identified stemness genes, we constructed two distinct stemness subtypes, denoted as C1 and C2. We subsequently conducted a comprehensive analysis of the differences between these subtypes using pathway enrichment methodology and immune infiltration algorithms. Furthermore, we identified key immune-related stemness genes by employing lasso regression analysis and a Cox survival regression model. We conducted in vitro experiments to ascertain the regulatory impact of the key gene on cell stemness. Additionally, we utilized immune infiltration analysis and pan-cancer analysis to delineate the functions attributed to this key gene. Lastly, single-cell RNA sequencing (scRNA-seq) was employed to conduct a more comprehensive examination of the key gene's role within the microenvironment.

RESULTS

In our study, we initially identified a set of 65 stemness-related genes in breast cancer cells displaying varying stemness capabilities. Subsequently, through survival analysis, we pinpointed 41 of these stemness genes that held prognostic significance. We observed that the C2 subtype exhibited a higher stemness capacity compared to the C1 subtype and displayed a more aggressive malignancy profile. Further analysis using Lasso-Cox algorithm identified LDLR as a pivotal immune-related stemness gene. It became evident that LDLR played a crucial role in shaping the immune microenvironment. In vitro experiments demonstrated that LDLR regulated the cell stemness of breast cancer. Immune infiltration analysis and pan-cancer analysis determined that LDLR inhibited the proliferation of immune cells and might promote tumor cell progression. Lastly, in our scRNA-seq analysis, we discovered that LDLR exhibited associations with stemness marker genes within breast cancer tissues. Moreover, LDLR demonstrated higher expression levels in tumor cells compared to immune cells, further emphasizing its relevance in the context of breast cancer.

CONCLUSION

LDLR is an important immune stemness gene that regulates cell stemness and enhances the crosstalk between breast cancer cancer cell stemness and tumor immune microenvironment.

Low-Density Lipoprotein Contributes to Endometrial Carcinoma Cell Proliferation, Migration, and Invasion by Activating the JAK-STAT Signaling Pathway

Background

Cholesterol-rich low-density lipoprotein (LDL) particles have been demonstrated to regulate breast cancer cell proliferation and migration, but their biological function and relevant mechanisms in endometrial carcinoma (EC) remain unclear.

Methods

Serum and tissue samples were collected from EC patients (n = 50) and patients with benign endometrial hyperplasia (n = 50). Ishikawa and RL95-2 cells were stimulated with different concentrations of LDL, followed by treatment with a JAK2 inhibitor (SD-1029). LDL concentrations were determined by ELISA. The in vitro biological behavior of cells was examined using the CCK-8 assay, EdU staining, and Transwell assay. The tumorigenicity of LDL in vivo was examined using a xenograft mouse model. western blotting, immunofluorescence, and immunohistochemistry studies were performed to measure related protein expression.

Results

The LDL concentrations and levels of p-JAK2 and p-STAT3 expression were elevated in the clinical samples. Similar trends in expression were detected in EC cells after LDL stimulation. LDL treatment significantly promoted EC cell proliferation, migration, and invasion, and also upregulated p-JAK2 and p-STAT3 expression in a dose-dependent manner. Moreover, SD-1029 dramatically blocked the LDL-mediated effects on EC cells. Intravenous injection of LDLs promoted tumor growth in the xenograft nude mice, and also increased p-JAK2, p-STAT3, and Ki-67 expression, and downregulated caspase-3 expression.

Conclusions

These findings indicate that LDLs exert an oncogenic effect in EC cells by activating the JAK/STAT signaling pathway, and also suggest the JAK/STAT pathway as a possible therapeutic target for EC.

Cholesterol reprograms glucose and lipid metabolism to promote proliferation in colon cancer cells

Hypercholesterolemia is often correlated with obesity which is considered a risk factor for various cancers. With the growing population of hypercholesterolemic individuals, there is a need to understand the role of increased circulatory cholesterol or dietary cholesterol intake towards cancer etiology and pathology. Recently, abnormality in the blood cholesterol level of colon cancer patients has been reported. In the present study, we demonstrate that alteration in cholesterol levels (through a high-cholesterol or high-fat diet) increases the incidence of chemical carcinogen-induced colon polyp occurrence and tumor progression in mice. At the cellular level, low-density lipoprotein cholesterol (LDLc) and high-density lipoprotein cholesterol (HDLc) promote colon cancer cell proliferation by tuning the cellular glucose and lipid metabolism. Mechanistically, supplementation of LDLc or HDLc promotes cellular glucose uptake, and utilization, thereby, causing an increase in lactate production by colon cancer cells. Moreover, LDLc or HDLc upregulates aerobic glycolysis, causing an increase in total ATP production through glycolysis, and a decrease in ATP generation by OXPHOS. Interestingly, the shift in the metabolic status towards a more glycolytic phenotype upon the availability of cholesterol supports rapid cell proliferation. Additionally, an alteration in the expression of the molecules involved in cholesterol uptake along with the increase in lipid and cholesterol accumulation was observed in cells supplemented with LDLc or HDLc. These results indicate that colon cancer cells directly utilize the cholesterol associated with LDLc or HDLc. Moreover, targeting glucose metabolism through LDH inhibitor (oxamate) drastically abrogates the cellular proliferation induced by LDLc or HDLc. Collectively, we illustrate the vital role of cholesterol in regulating the cellular glucose and lipid metabolism of cancer cells and its direct effect on the colon tumorigenesis.

Is cholesterol a risk factor for breast cancer incidence and outcome?

Cholesterol plays important roles in many physiological processes, including cell membrane structure and function, hormone synthesis, and the regulation of cellular homeostasis. The role of cholesterol in breast cancer is complex, and some studies have suggested that elevated cholesterol levels may be associated with an increased risk of developing breast cancer, while others have found no significant association. On the other hand, other studies have shown that, for total cholesterol and plasma HDL-associated cholesterol levels, there was inverse association with breast cancer risk. One possible mechanism by which cholesterol may contribute to breast cancer risk is as a key precursor of estrogen. Other potential mechanisms by which cholesterol may contribute to breast cancer risk include its role in inflammation and oxidative stress, which have been linked to cancer progression. Cholesterol has also been shown to play a role in signaling pathways regulating the growth and proliferation of cancer cells. In addition, recent studies have shown that cholesterol metabolism can generate tumor promoters such as cholesteryl esters, oncosterone, 27-hydroxycholesterol but also tumor suppressor metabolites such as dendrogenin A. This review summarizes some of the most important clinical studies that have evaluated the role of cholesterol or its derivatives in breast cancer. It also addresses the role of cholesterol and its derivatives at the cellular level.

The effects of statins in patients with advanced-stage cancers - a systematic review and meta-analysis

Background

Statin therapy has been shown to reduce mortality in a wide range of cancer types and overall stages. Still, there is uncertainty about its efficacy in increasing survival among advanced cancer patients.

Methods

We conducted a meta-analysis with data from all studies that compared the hazard ratio of overall survival, cancer-specific survival, and progression-free survival in patients with advanced-stage cancer who receive statin therapy. Studies were selected from the PubMed, Embase, and Web of Science databases from their inception to December 31, 2022. Cancer types are limited to those rarely screened during the annual examination and more likely to develop into advanced stages, such as lung, pancreatic and ovarian cancers. This resulted in 27 studies eligible for meta-analysis.

Results

Statin therapy was associated with a 26% decreased risk of overall survival (HR, 0.74; 95% CI, 0.67, 0.81), 26% decreased risk of cancer-specific survival (HR, 0.74; 95% CI, 0.61-0.88), and 24% decreased risk of progression-free survival (HR, 0.76; 95% CI, 0.65-0.87) for advanced-stage cancer patients. The associations were not attenuated or reinforced by study design, study regions, cancer types, or other medical care. Concomitant use of other anticancer medications did not result in confounding effects.

Conclusions

Statin therapy produces significant benefits on overall survival and cancer-specific survival. Although the benefits might be lower than the approved immunotherapy medications, its cost-effectiveness could lead to dramatic health consequences. Concomitant use of statin drugs as cancer treatments is highly recommended in future clinical trials.

Low-Density Lipoprotein Receptor Is a Key Driver of Aggressiveness in Thyroid Tumor Cells

We previously described the role of low-density lipoprotein (LDL) in aggressiveness in papillary thyroid cancer (PTC). Moreover, the MAPK signaling pathway in the presence of BRAF V600E mutation is associated with more aggressive PTC. Although the link between MAPK cascade and LDL receptor (LDLR) expression has been previously described, it is unknown whether LDL can potentiate the adverse effects of PTC through it. We aimed to investigate whether the presence of LDL might accelerate the oncogenic processes through MAPK pathway in presence or absence of BRAF V600E in two thyroid cell lines: TPC1 and BCPAP (wild-type and BRAF V600E, respectively). LDLR, PI3K-AKT and RAS/RAF/MAPK (MEK)/ERK were analyzed via Western blot; cell proliferation was measured via MTT assay, cell migration was studied through wound-healing assay and LDL uptake was analyzed by fluorometric and confocal analysis. TPC1 demonstrated a time-specific downregulation of the LDLR, while BCPAP resulted in a receptor deregulation after LDL exposition. LDL uptake was increased in BCPAP over-time, as well as cell proliferation (20% higher) in comparison to TPC1. Both cell lines differed in migration pattern with a wound closure of 83.5 ± 9.7% after LDL coculture in TPC1, while a loss in the adhesion capacity was detected in BCPAP. The siRNA knockdown of LDLR in LDL-treated BCPAP cells resulted in a p-ERK expression downregulation and cell proliferation modulation, demonstrating a link between LDLR and MAPK pathway. The modulation of BRAF-V600E using vemurafenib-impaired LDLR expression decreased cellular proliferation. Our results suggest that LDLR regulation is cell line-specific, regulating the RAS/RAF/MAPK (MEK)/ERK pathway in the LDL-signaling cascade and where BRAF V600E can play a critical role. In conclusion, targeting LDLR and this downstream signaling cascade, could be a new therapeutic strategy for PTC with more aggressive behavior, especially in those harboring BRAF V600E.

Prognostic value of perioperative serum low-density lipoprotein cholesterol level for postoperative prognosis of pancreatic cancer: a retrospective study

BACKGROUND

As a common malignant tumour, pancreatic cancer (PC) has the worst clinical outcome. Early evaluation of the postoperative prognosis has certain clinical value. Low-density lipoprotein cholesterol (LDL-c), which is mainly composed of cholesteryl esters, phospholipids, and proteins, plays an important role in transporting cholesterol into peripheral tissues. LDL-c has also been reported to be correlated with the occurrence and progression of malignant tumours and can predict postoperative prognosis in various tumours.

AIMS

To determine correlation between serum LDL-c level and clinical outcome in PC patients after surgery.

METHODS

Data of PC patients that received surgery at our department from January 2015 to December 2021 were retrospectively analysed. Receiver operating characteristic (ROC) curves between perioperative serum LDL-c at different timepoints and survival rate at postoperative 1-year were drawn, and the optimal cut-off value was calculated. Patients were categorized into low and high LDL-c groups, and their clinical data and outcome were compared. Univariate and multivariate analyses were applied to screen out risk markers for poor prognosis of PC patients after surgery.

RESULTS

The area under the ROC curve of serum LDL-c at 4 weeks after surgery and prognosis was 0.669 (95% CI: 0.581-0.757), and the optimal cut-off value was 1.515 mmol/L. The median disease-free survival (DFS) rates of low and high LDL-c groups were 9 months and 16 months, respectively, and the 1-, 2- and 3-year DFS rates were 42.6%, 21.1% and 11.7% in low LDL-c group, respectively, and, 60.2%, 35.3% and 26.2% in high LDL-c group, respectively (P = 0.005). The median overall survival (OS) rates of low and high LDL-c groups were 12 months and 22 months, respectively, and the 1-, 2- and 3-year OS rates were 46.8%, 22.6% and 15.8% in low LDL-c group, respectively, and 77.9%, 46.8% and 30.4% in high LDL-c group, respectively (P = 0.004). Multivariate analysis confirmed low postoperative 4-week serum LDL-c as independent risk marker for early tumour recrudesce and poor clinical outcome in PC patients.

CONCLUSION

High postoperative 4-week serum LDL-c is a prognostic marker for prolonged DFS and OS time in PC patients.

The impact of lipid metabolism on breast cancer: a review about its role in tumorigenesis and immune escape

BACKGROUND

Breast cancer (BC) is the second most frequent type of cancer in the world and most common among women, configuring a major challenge to global health. BC is a complex and heterogeneous disease that can be subdivided into distinct tumor types based on the expression of molecular markers predicting patient outcomes and response to therapy. A growing number of studies have tried to expand the known markers by investigating the association of altered lipid metabolism with BC immune escape, progression, and metastasis. In this review, we describe the metabolic peculiarities of each BC subtype, understanding how this influences its aggressiveness and identifying whether these intrinsic vulnerabilities of each subtype can play a role in therapeutic management and may affect immune system cells in the tumor microenvironment.

CONCLUSION

The evidence suggests so far that when changes occur in lipid pathways, it can affect the availability of structural lipids for membrane synthesis, lipid synthesis, and degradation that contribute to energy homeostasis and cell signaling functions. These findings will guide the next steps on the path to understanding the mechanisms underlying how lipids alterations are related to disparities in chemotherapeutic response and immune escape in BC. Video Abstract.

The evolving landscape of PCSK9 inhibition in cancer

Cancer is a disease with a significant global burden in terms of premature mortality, loss of productivity, healthcare expenditures, and impact on mental health. Recent decades have seen numerous advances in cancer research and treatment options. Recently, a new role of cholesterol-lowering PCSK9 inhibitor therapy has come to light in the context of cancer. PCSK9 is an enzyme that induces the degradation of low-density lipoprotein receptors (LDLRs), which are responsible for clearing cholesterol from the serum. Thus, PCSK9 inhibition is currently used to treat hypercholesterolemia, as it can upregulate LDLRs and enable cholesterol reduction through these receptors. The cholesterol-lowering effects of PCSK9 inhibitors have been suggested as a potential mechanism to combat cancer, as cancer cells have been found to increasingly rely on cholesterol for their growth needs. Additionally, PCSK9 inhibition has demonstrated the potential to induce cancer cell apoptosis through several pathways, increase the efficacy of a class of existing anticancer therapies, and boost the host immune response to cancer. A role in managing cancer- or cancer treatment-related development of dyslipidemia and life-threatening sepsis has also been suggested. This review examines the current evidence regarding the effects of PCSK9 inhibition in the context of different cancers and cancer-associated complications.

Mitochondrial Metabolism Drives Low-density Lipoprotein-induced Breast Cancer Cell Migration

Most cancer-related deaths are due to metastases. Systemic factors, such as lipid-enriched environments [as low-density lipoprotein (LDL)-cholesterol], favor breast cancer, including triple-negative breast cancer (TNBC) metastasis formation. Mitochondria metabolism impacts TNBC invasive behavior but its involvement in a lipid-enriched setting is undisclosed. Here we show that LDL increases lipid droplets, induces CD36 and augments TNBC cells migration and invasion in vivo and in vitro. LDL induces higher mitochondrial mass and network spread in migrating cells, in an actin remodeling-dependent manner, and transcriptomic and energetic analyses revealed that LDL renders TNBC cells dependent on fatty acids (FA) usage for mitochondrial respiration. Indeed, engagement on FA transport into the mitochondria is required for LDL-induced migration and mitochondrial remodeling. Mechanistically, LDL treatment leads to mitochondrial long-chain fatty acid accumulation and increased reactive oxygen species (ROS) production. Importantly, CD36 or ROS blockade abolished LDL-induced cell migration and mitochondria metabolic adaptations. Our data suggest that LDL induces TNBC cells migration by reprogramming mitochondrial metabolism, revealing a new vulnerability in metastatic breast cancer.

Significance

LDL induces breast cancer cell migration that relies on CD36 for mitochondrial metabolism and network remodeling, providing an antimetastatic metabolic strategy.

Dyslipidemia is associated with a poor prognosis of breast cancer in patients receiving neoadjuvant chemotherapy

BACKGROUND

Lipid metabolism disorders may be involved in the occurrence and development of breast cancer. This study aimed to investigate the serum lipid changes during neoadjuvant chemotherapy for breast cancer and the effect of dyslipidemia on the prognosis of breast cancer patients.

METHODS

We collected the data from 312 breast cancer patients who underwent surgery after receiving standard neoadjuvant therapy. χ² test and T-test were employed to analyze the effect of chemotherapy on the serum lipid metabolism of patients. The effects of dyslipidemia on the disease-free survival (DFS) of patients with breast cancer were analyzed by χ² test and COX regression analysis.

RESULTS

A total of 56 out of 312 patients (17.9%) suffered from relapse. The baseline serum lipid level of the patients was significantly correlated with their age and body mass index (BMI) (p < 0.05). Chemotherapy increased the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol, but decreased the level of high-density lipoprotein cholesterol (p < 0.001). Preoperative dyslipidemia was significantly associated with the axillary pCR rate (p < 0.05). COX regression analysis revealed that the full-course serum lipid level (HR = 1.896 [95%CI 1.069-3.360]; p = 0.029), N stage (HR = 4.416 [95%CI 2.348-8.308]; p < 0.001) and the total pCR rate (HR = 4.319 [95%CI 1.029-18.135]; p = 0.046) acted as prognostic factors affecting DFS in breast cancer. The relapse rate in patients with a high level of total cholesterol was higher than that in patients with a high level of triglycerides (61.9% vs 30.0%; p < 0.05).

CONCLUSIONS

Dyslipidemia deteriorated after chemotherapy. The full-course serum lipid level may thus serve as a blood marker for predicting breast cancer prognosis. Serum lipids should therefore be closely monitored in breast cancer patients throughout the treatment course, and patients with dyslipidemia should be treated in a timely manner.

Low-Density Lipoprotein Pathway Is a Ubiquitous Metabolic Vulnerability in High Grade Glioma Amenable for Nanotherapeutic Delivery

Metabolic reprogramming, through increased uptake of cholesterol in the form of low-density lipoproteins (LDL), is one way by which cancer cells, including high grade gliomas (HGG), maintain their rapid growth. In this study, we determined LDL receptor (LDLR) expression in HGGs using immunohistochemistry on tissue microarrays from intra- and inter tumour regions of 36 adult and 133 paediatric patients to confirm LDLR as a therapeutic target. Additionally, we analysed expression levels in three representative cell line models to confirm their future utility to test LDLR-targeted nanoparticle uptake, retention, and cytotoxicity. Our data show widespread LDLR expression in adult and paediatric cohorts, but with significant intra-tumour variation observed between the core and either rim or invasive regions of adult HGG. Expression was independent of paediatric tumour grade or identified clinicopathological factors. LDLR-expressing tumour cells localized preferentially within perivascular niches, also with significant adult intra-tumour variation. We demonstrated variable levels of LDLR expression in all cell lines, confirming their suitability as models to test LDLR-targeted nanotherapy delivery. Overall, our study reveals the LDLR pathway as a ubiquitous metabolic vulnerability in high grade gliomas across all ages, amenable to future consideration of LDL-mediated nanoparticle/drug delivery to potentially circumvent tumour heterogeneity.

Metabolic signatures of lymphangioleiomyomatosis in biofluids: nuclear magnetic resonance (NMR)-based metabonomics of blood plasma: a case-control study

Background

Our aim was to analyze and compare the characteristics and differences of blood metabolites between lymphangioleiomyomatosis (LAM) patients and healthy controls, in order to find biomarkers that can be used for the diagnosis and classification of LAM.

Methods

Between January 2020 to January 2022, 61 eligible LAM patients [51 sporadic LAM (S-LAM) and 10 tuberous sclerosis complex LAM (TSC-LAM)] from the First Affiliated Hospital of Guangzhou Medical University and 30 healthy controls were enrolled. Blood samples were taken for nuclear magnetic resonance (NMR) detection. Data analysis was performed by the umbrella program, and Wilcoxon analysis was used for comparisons between groups. The difference indicators were modeled by logistic regression. Diagnostic accuracy of the best predictive parameters was evaluated by the area under the receiver operating characteristic (ROC) curve (AUC), and the sensitivity and specificity were calculated.

Results

The indexes differed between LAM patients and healthy controls, S-LAM patients and healthy controls, and between TSC-LAM patients and healthy controls. There were two different metabolic indexes between S-LAM and TSC-LAM patients. After logistic regression modeling and ROC analysis, methionine (AUC =0.929, sensitivity =73.8%, specificity =100%, cut-off value =0.011 mmol/L) and acetic acid (AUC =0.966, sensitivity =95.1%, specificity =90%, cut-off value =0.006 mmol/L) had the highest diagnostic efficiency in LAM patients, and could be used to distinguish between affected and healthy people. Methionine was significantly associated with pneumothorax (P<0.05), and creatinine was significantly correlated with hysteromyoma (P<0.05).

Conclusions

Methionine and acetic acid in the plasma of LAM patients are potential biomarkers. Methionine was also associated with pneumothorax in LAM patients. Also, acetone and creatinine were promising metabolic markers to distinguish S-LAM from TSC-LAM. NMR as a new non-invasive diagnostic method had a good discriminatory power for LAM.

Correlations between serum lipid and Ki-67 levels in different breast cancer molecular subcategories

Breast cancer has the highest incidence rate among all cancer types worldwide, seriously threatening women's health. The present retrospective study explored differences in serum lipid contents in different breast cancer (BC) subcategories and their correlation with Ki-67 expression levels in patients with invasive BC with the aim of identifying novel diagnostic and prognostic indicators for personalized BC treatment. The study included 170 patients diagnosed with BC who were diagnosed with invasive BC by postoperative pathological examination. Data on patient age, body mass index and menopausal status were collected, in addition to estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 (HER2) and antigen Ki-67 expression levels and pathological tumor type. Preoperative circulating lipid levels, specifically the levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and apolipoproteins A1 (ApoA1) and B (ApoB) were also obtained. Molecular subcategories of BC were grouped based on their immunohistochemistry. Differences in serum lipid levels between the groups were assessed, and correlations between serum lipid and Ki-67 expression levels were explored. While TC, LDL-C, HDL-C and ApoA1 levels differed significantly among molecular subcategories. TG and ApoB levels did not. Circulating TC and LDL-C levels were considerably higher in patients with triple-negative BC (TNBC) and HER2-positive [hormone receptor (HR)-negative] BC than in those with luminal A and B (HER2-negative) BC. Serum HDL-C levels were significantly diminished in the TNBC and HER2-positive (HR-negative) groups compared with the luminal A and B (HER2-negative) groups. ApoA1 levels were significantly reduced in cases of TNBC and HER2-positive (HR-negative) BC compared with luminal A and B BC. Ki-67 expression levels were positively correlated with circulating TC and LDL-C levels and inversely correlated with circulating HDL-C and ApoA1 levels but exhibited no correlation with serum ApoB and TG levels. The results indicate that elevated TC and LDL-C levels and diminished HDL-C and ApoA1 levels were high-risk factors in patients with TNBC and HER2-positive (HR-negative) BC, but not patients with luminal subcategories of BC. Abnormal serum lipid levels were correlated with Ki-67 expression levels, with elevated circulating TC and LDL-C levels and reduced circulating HDL-C and ApoA1 levels indicating a poor prognosis in patients with BC.

Lipid Metabolism Heterogeneity and Crosstalk with Mitochondria Functions Drive Breast Cancer Progression and Drug Resistance

Breast cancer (BC) is a heterogeneous disease that can be triggered by genetic alterations in mammary epithelial cells, leading to diverse disease outcomes in individual patients. The metabolic heterogeneity of BC enhances its ability to adapt to changes in the tumor microenvironment and metabolic stress, but unfavorably affects the patient's therapy response, prognosis and clinical effect. Extrinsic factors from the tumor microenvironment and the intrinsic parameters of cancer cells influence their mitochondrial functions, which consequently alter their lipid metabolism and their ability to proliferate, migrate and survive in a harsh environment. The balanced interplay between mitochondria and fatty acid synthesis or fatty acid oxidation has been attributed to a combination of environmental factors and to the genetic makeup, oncogenic signaling and activities of different transcription factors. Hence, understanding the mechanisms underlying lipid metabolic heterogeneity and alterations in BC is gaining interest as a major target for drug resistance. Here we review the major recent reports on lipid metabolism heterogeneity and bring to light knowledge on the functional contribution of diverse lipid metabolic pathways to breast tumorigenesis and therapy resistance.

Cholesterol: An important actor on the cancer immune scene

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

Changes in CoQ10/Lipids Ratio, Oxidative Stress, and Coenzyme Q10 during First-Line Cisplatin-Based Chemotherapy in Patients with Metastatic Urothelial Carcinoma (mUC)

Oxidative stress plays an important role in cancer pathogenesis, and thiobarbituric acid-reactive substance level (TBARS)—a parameter of lipid peroxidation—has prognostic significance in chemotherapy-naive patients with metastatic urothelial carcinoma (mUC). However, the effect of cisplatin (CDDP)-based chemotherapy on oxidative stress, coenzyme Q10, and antioxidants remains unknown. The objective of this prospective study was to determine possible changes in the CoQ10 (coenzyme Q10)/lipids ratio, antioxidants (α-tocopherol, γ-tocopherol, β-carotene, CoQ10), total antioxidant status (TAS), and TBARS in plasma at baseline and during first-line chemotherapy based on CDDP in mUC subjects. In this prospective study, 63 consecutive patients were enrolled. The median age was 66 years (range 39−84), performance status according to the Eastern Cooperative Oncology Group (ECOG) was 2 in 7 subjects (11.1%), and visceral metastases were present in 31 (49.2%) patients. Plasma antioxidants were determined by HPLC and TAS and TBARS spectrophotometrically. After two courses of chemotherapy, we recorded significant enhancements compared to baseline for total cholesterol (p < 0.0216), very low-density lipoprotein (VLDL) cholesterol (p < 0.002), triacylglycerols (p < 0.0083), α-tocopherol (p < 0.0044), and coenzyme Q10-TOTAL (p < 0.0001). Ratios of CoQ10/total cholesterol, CoQ10/HDL-cholesterol, and CoQ10/LDL-cholesterol increased during chemotherapy vs. baseline (p < 0.0048, p < 0.0101, p < 0.0032, respectively), while plasma TBARS declined (p < 0.0004). The stimulation of antioxidants could be part of the defense mechanism during CDDP treatment. The increased index of CoQ10-TOTAL/lipids could reflect the effect of CDDP protecting lipoproteins from peroxidation.

Interleukin-17 Family Cytokines in Metabolic Disorders and Cancer

Interleukin-17 (IL-17) family cytokines are potent drivers of inflammatory responses. Although IL-17 was originally identified as a cytokine that induces protective effects against bacterial and fungal infections, IL-17 can also promote chronic inflammation in a number of autoimmune diseases. Research in the last decade has also elucidated critical roles of IL-17 during cancer development and treatment. Intriguingly, IL-17 seems to play a role in the risk of cancers that are associated with metabolic disorders. In this review, we summarize our current knowledge on the biochemical basis of IL-17 signaling, IL-17′s involvement in cancers and metabolic disorders, and postulate how IL-17 family cytokines may serve as a bridge between these two types of diseases.

A cholesterogenic gene signature for predicting the prognosis of young breast cancer patients

Purpose

We aimed to establish a cholesterogenic gene signature to predict the prognosis of young breast cancer (BC) patients and then verified it using cell line experiments.

Methods

In the bioinformatic section, transcriptional data and corresponding clinical data of young BC patients (age ≤ 45 years) were downloaded from The Cancer Genome Atlas (TCGA) database for training set. Differentially expressed genes (DEGs) were compared between tumour tissue (n = 183) and normal tissue (n = 30). By using univariate Cox regression and multi COX regression, a five-cholesterogenic-gene signature was established to predict prognosis. Subgroup analysis and external validations of GSE131769 from the Gene Expression Omnibus (GEO) were performed to verify the signature. Subsequently, in experiment part, cell experiments were performed to further verify the biological roles of the five cholesterogenic genes in BC.

Results

In the bioinformatic section, a total of 97 upregulated genes and 124 downregulated cholesterogenic genes were screened as DEGs in the TCGA for training the model. A risk scoring signature contained five cholesterogenic genes (risk score = -1.169 × GRAMD1C -0.992 × NFKBIA + 0.432 × INHBA + 0.261 × CD24 -0.839 × ACSS2) was established, which could differentiate the prognosis of young BC patients between high-risk and low-risk group (<0.001). The prediction value of chelesterogenic gene signature in excellent with AUC was 0.810 in TCGA dataset. Then the prediction value of the signature was verified in GSE131769 with P = 0.033. In experiment part, although the downregulation of CD24, GRAMD1C and ACSS2 did not significantly affect cell viability, NFKBIA downregulation promoted the viability, colony forming ability and invasion capability of BC cells, while INHBA downregulation had the opposite effects.

Conclusion

The five-cholesterogenic-gene signature had independent prognostic value and robust reliability in predicting the prognosis of young BC patients. The cell experiment results suggested that NFKBIA played a protective role, while INHBA played the pro-cancer role in breast cancer.

27-Hydroxycholesterol Binds GPER and Induces Progression of Estrogen Receptor-Negative Breast Cancer

Simple Summary

Breast cancer is the most common cancer in women, and there is a known link between high cholesterol levels and breast cancer. However, how cholesterol impacts breast cancer is poorly understood, particularly in the case of an aggressive form of cancer known as estrogen receptor negative breast cancer. Using cells in culture and models of breast tumors in mice, we have determined that an abundant metabolite of cholesterol known as 27-hydroxycholesterol stimulates estrogen receptor negative breast cancer growth. We have also determined how 27-hydroxycholesterol stimulates the growth, identifying a new mechanism of action of 27-hydroxycholesterol. These new findings may explain the link between high cholesterol and estrogen receptor negative breast cancer, and they may lead to the development of new therapies for a type of breast cancer that presently lacks specific treatments.

Abstract

Cholesterol affects the proliferation of breast cancer (BC) and in particular of estrogen receptor-negative (ER−) BC. Cholesterol is converted to 27-hydroxycholesterol (27HC), which promotes the growth of ER+ BC. Potentially, 27HC can be involved in cholesterol-dependent ER− BC proliferation. Stable MDA-MB-231 silenced clones for CYP7B1 (27HC metabolizing enzyme) show an increased basal proliferation rate, which is not observed in the presence of lipoprotein-deprived serum. Furthermore, the treatment of SKBR3, MDA-MB-231 and MDA-MB-468 with 27HC increased cell proliferation that was prevented by G15, a selective G Protein-Coupled Estrogen Receptor (GPER) inhibitor, suggested this receptor to be a potential 27HC target. Binding experiments demonstrate that 27HC is a new ligand for GPER. We show that ERK1/2 and NFκB are part of the 27HC/GPER pathway. The stable silencing of GPER prevents NFκB activation and reduces basal and 27HC-dependent tumor growth. Additionally, conditioned medium from ER− BC cells treated with 27HC promotes tube formation, which does not occur with CM from GPER silenced cells. Collectively, these data demonstrate that cholesterol conversion into 27HC promotes ER− BC growth and progression, and the expression of GPER is required for its effects.

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

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

Identification of a Novel Immune-Related lncRNA CTD-2288O8.1 Regulating Cisplatin Resistance in Ovarian Cancer Based on Integrated Analysis

Ovarian cancer (OC) is the most lethal gynecological malignancy, in which chemoresistance is a crucial factor leading to the poor prognosis. Recently, immunotherapy has brought new light for the treatment of solid tumors. Hence, as a kind of immunologically active cancer, it is reasonably necessary to explore the potential mechanism between immune characteristics and cisplatin resistance in OC. Our study focused on the important role of cisplatin resistance-related lncRNAs on mediating the OC tumor immune microenvironment (TIME) using an integrative analysis based on the Cancer Genome Atlas (TCGA) database. First, the cisplatin resistance-related differentially expressed lncRNAs (DELs) and mRNAs (DEMs) were preliminarily screened to construct a DEL–DEM co-expression network. Next, the protein–protein interaction (PPI) network and pivot analysis were performed to reveal the relevance of these lncRNAs with tumor immune response. Second, the novel lncRNA CTD-2288O8.1 was identified as a key gene for the OC cisplatin resistance formation by qRT-PCR and survival analysis. Gain- and loss-of-function assays (Cell Counting Kit-8 (CCK-8) assay, wound-healing scratch assay, transwell assay, and colony formation assay) further verified the activity of CTD-2288O8.1 in OC progression as well. Third, gene set enrichment analysis (GSEA) was applied along with the correlation analyses of CTD-2288O8.1 with ImmuneScore, tumor-infiltrating immune cells (TICs), and immune inhibitory checkpoint molecules, illustrating that CTD-2288O8.1 was strongly associated with the TIME and has the potential to predict the effect of OC immunotherapy. In addition, basic experiments demonstrated that the expression of CTD-2288O8.1 impacted the EGFR/AKT signal pathway activity of OC tumor cells. Of greater significance, it promoted the M2 polarization of macrophage, which is a type of the most important components of the TIME in solid tumor. Taking together, our study revealed cisplatin resistance-related lncRNAs closely linked with tumor immunity in OC, underscoring the potential mechanism of the TIME in conferring cisplatin resistance, which provided the research basis for further clinical treatment. CTD-2288O8.1 was identified to mediate cisplatin resistance and affect the response of immunotherapy, which could serve as a promising biomarker for guiding clinical treatment and improving prognosis in OC.

Lipoproteins and cancer: The role of HDL-C, LDL-C, and cholesterol-lowering drugs

Cholesterol is an amphipathic sterol molecule that is vital for maintaining normal physiological homeostasis. It is a relatively complicated molecule with 27 carbons whose synthesis starts with 2-carbon units. This in itself signifies the importance of this molecule. Cholesterol serves as a precursor for vitamin D, bile acids, and hormones, including estrogens, androgens, progestogens, and corticosteroids. Although essential, high cholesterol levels are associated with cardiovascular and kidney diseases and cancer initiation, progression, and metastasis. Although there are some contrary reports, current literature suggests a positive association between serum cholesterol levels and the risk and extent of cancer development. In this review, we first present a brief overview of cholesterol biosynthesis and its transport, then elucidate the role of cholesterol in the progression of some cancers. Suggested mechanisms for cholesterol-mediated cancer progression are plentiful and include the activation of oncogenic signaling pathways and the induction of oxidative stress, among others. The specific roles of the lipoprotein molecules, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), in this pathogenesis, are also reviewed. Finally, we hone on the potential role of some cholesterol-lowering medications in cancer.

Decreased serum apolipoprotein A1 level predicts poor prognosis of patients with de novo myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes (MDS) is a group of heterogeneous myeloid clonal diseases originating from hematopoietic stem cells. It has been demonstrated that apolipoproteins A1(ApoA1) are associated with disease risk in many cancer types. However, there still lacks evidence regarding the link between ApoA1 and MDS. This study was designed to investigate the prognostic value of pretreatment ApoA1 levels in MDS patients.

METHODS

We retrospectively analyzed a cohort of 228 MDS patients to explore the prognostic value of the serum ApoA1 levels at diagnosis. Patients were divided into the high ApoA1 group and the low ApoA1 group. The prognostic significance was determined by univariate and multivariate Cox hazard models.

RESULTS

MDS patients with low ApoA1 levels had significantly shorter overall survival (OS, P < 0.0001) along with a higher frequency of TP53 mutation (P = 0.002). Based on univariate analysis, age (≥ 60 years), gender (male), lower levels of hemoglobin (< 10 g/dl), HDL (≤0.91 mmol/L), higher bone marrow blast percentage (> 5%), higher IPSS-R scores and poorer karyotype were significantly associated with decreased OS. However, low ApoA1 level did not influence leukemia-free survival (LFS, P = 0.367). Multivariate Cox proportional hazards regression analysis indicated that low ApoA1 level (≤ 1.02 g/L) was also an independent adverse prognostic factor for OS in MDS (P = 0.034).

CONCLUSIONS

Decreased ApoA1 level predicts a poor prognosis of MDS patients and thus provides a novel evaluation factor for them that is independent of the IPSS-R system.

Predictive value of preoperative platelet-to-albumin ratio and apolipoprotein B-to-apolipoprotein A1 ratio for osteosarcoma in children and adolescents: a retrospective study of 118 cases

Background

This retrospective study investigated biomarkers that can reflect coagulation, inflammation, and lipid abnormalities: platelet-to-albumin ratio (PAR), platelet-to lymphocyte ratio (PLR), low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (LDL-C/HDL-C), apolipoprotein B-to-apolipoprotein ratio (ApoB/ApoA1) whether may be viable prognostic predictors in children and adolescents with osteosarcoma.

Methods

The retrospective review has enrolled a total of 118 children and adolescent patients diagnosed with osteosarcoma. Analyses with a receiver operating characteristic (ROC) curve were performed to evaluate the optimal cut-off values and to compare the area under curves (AUC). Kaplan–Meier curves were used to visualize survival outcome and a Cox proportional hazards model were used to confirm independent prognostic factors.

Results

Osteosarcoma patients in high PAR group (> 4.41) and high ApoB/ApoA1 group (> 0.82) experienced significantly shorter overall survival compared with those in low PAR group (≤ 4.41) and low ApoB/ApoA1 group (≤ 0.82). In univariate and multivariable analyses, preoperative PAR and ApoB/ApoA1 were identified as independent prognostic factors for OS in children and adolescents with osteosarcoma.

Conclusion

Preoperative PAR and ApoB/ApoA1 can be used as promising predictors in children and adolescents with osteosarcoma to help clinicians recognize patients with an increased risk of poor prognosis.

Lipids, Anthropometric Measures, Smoking and Physical Activity Mediate the Causal Pathway From Education to Breast Cancer in Women: A Mendelian Randomization Study

Purpose

We aimed to investigate whether obtaining a higher level of education was causally associated with lower breast cancer risk and to identify the causal mechanism linking them.

Methods

The main data analysis used publicly available summary-level data from 2 large genome-wide association study consortia. Mendelian randomization (MR) analysis used 65 genetic variants derived from the Social Science Genetic Association Consortium as instrumental variables for years of schooling. The outcomes from the Breast Cancer Association Consortium (BCAC) were the overall breast cancer risk (122,977 cases/105,974 controls in women) and the two subtypes: estrogen receptor (ER)-positive breast cancer and ER-negative breast cancer. Fixed and random effects inverse variance weighted methods were used to estimate the causal effects, along with other additional MR methods for sensitivity analyses.

Results

Results showed that each additional standard deviation of 4.2 years of education was causally associated with a 27% lower risk of ER-negative breast cancer (odds ratio, 0.73; 95% confidence interval, 0.64–0.84; p-value < 0.001). This finding was consistent with the results of the sensitivity analyses. Physical activities can help improve the protective effect of education against breast cancer, with relatively large mediation proportions. Education increases the risk of ER-positive breast cancer due to alterations in high-density lipoprotein level, triglyceride level, height, waist-to-hip ratio, body mass index, and smoking status, with relative medium mediation proportions. Other mediators including low-density lipoprotein, hip circumference, number of cigarettes smoked per day, time spent performing light physical activity, and performing vigorous physical activity for > 10 minutes explain a small part of the causal effect of education on the risk of developing breast cancer, and their mediation proportion is approximately 1%.

Conclusion

A low level of education is a causal risk factor in the development of breast cancer as it is associated with poor lipid profile, obesity, smoking, and types of physical activity.

Low Density Lipoprotein Receptor (LDLR) and 3-Hydroxy-3-Methylglutaryl Coenzyme a Reductase (HMGCR) Expression are Associated with Platinum-Resistance and Prognosis in Ovarian Carcinoma Patients

Purpose

The efficacy of post-surgery platinum-based chemotherapy, the primary choice for the treatment of ovarian cancer (OC), is greatly reduced by the development of drug-resistance. In this study, we investigated the association of expression low-density lipoprotein receptor (LDLR) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), two cholesterol metabolism-related proteins, in OC tissues and chemoresistance and patient prognosis.

Methods

Survival analysis using LDLR and HMGCR expression in the ovarian cancer patients using the dataset of Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) was carried out online. A retrospective study was performed on 65 patients who had undergone surgery for ovarian cancer. In addition, patients were divided into 2 groups: platinum resistance group and platinum sensitivity group. Serum lipid metabolism data were collected and analyzed. Protein expressions of LDLR and HMGCR in ovarian cancer tissue were detected by immunohistochemistry.

Results

Online survival analysis showed that patients with higher LDLR expression had poorer prognosis than those with lower LDLR expression in ovarian cancer cells, while a higher HMGCR expression was associated with better OC prognosis. Overall survival (OS) and disease-free survival (DFS) were lower in patients with higher LDLR levels (OS: P=0.046, DFS: P=0.009). Platinum-resistant patients had higher levels of low-density lipoprotein (LDL) and cholesterol in serum as compared with platinum-sensitive patients (P<0.001). Immunohistochemistry showed that LDLR expression was high and HMGCR was low in platinum-resistant patients.

Conclusion

The expression of LDLR and HMGCR proteins, involved in the regulation of cholesterol metabolism and the plasma LDL and cholesterol levels were significantly different in platinum-resistant and platinum-sensitive ovarian cancer patients. We postulate that cholesterol metabolic reprogramming might play a role in platinum resistance in ovarian cancer.

LRP-1 Matricellular Receptor Involvement in Triple Negative Breast Cancer Tumor Angiogenesis

Background: LRP-1 is a multifunctional scavenger receptor belonging to the LDLR family. Due to its capacity to control pericellular levels of various growth factors and proteases, LRP-1 plays a crucial role in membrane proteome dynamics, which appears decisive for tumor progression. Methods: LRP-1 involvement in a TNBC model was assessed using an RNA interference strategy in MDA-MB-231 cells. In vivo, tumorigenic and angiogenic effects of LRP-1-repressed cells were evaluated using an orthotopic xenograft model and two angiogenic assays (Matrigel^® plugs, CAM). DCE-MRI, FMT, and IHC were used to complete a tumor longitudinal follow-up and obtain morphological and functional vascular information. In vitro, HUVECs’ angiogenic potential was evaluated using a tumor secretome, subjected to a proteomic analysis to highlight LRP-1-dependant signaling pathways. Results: LRP-1 repression in MDA-MB-231 tumors led to a 60% growth delay because of, inter alia, morphological and functional vascular differences, confirmed by angiogenic models. In vitro, the LRP-1-repressed cells secretome restrained HUVECs’ angiogenic capabilities. A proteomics analysis revealed that LRP-1 supports tumor growth and angiogenesis by regulating TGF-β signaling and plasminogen/plasmin system. Conclusions: LRP-1, by its wide spectrum of interactions, emerges as an important matricellular player in the control of cancer-signaling events such as angiogenesis, by supporting tumor vascular morphology and functionality.

Lipoproteins as Markers for Monitoring Cancer Progression

Lipoproteins are among the contributors of energy for the survival of cancer cells. Studies indicate there are complex functions and metabolism of lipoproteins in cancer. The current review is aimed at providing updates from studies related to the monitoring of lipoproteins in different types of cancer. This had led to numerous clinical and experimental studies. The review covers the major lipoproteins such as LDL cholesterol (LDL-C), oxidized low-density lipoprotein cholesterol (oxLDL-C), very low-density lipoprotein cholesterol (VLDL-C), and high-density lipoprotein cholesterol (HDL-C). This is mainly due to increasing evidence from clinical and experimental studies that relate association of lipoproteins with cancer. Generally, a significant association exists between LDL-C with carcinogenesis and high oxLDL with metastasis. This warrants further investigations to include Mendelian randomization design and to be conducted in a larger population to confirm the significance of LDL-C and its oxidized form as prognostic markers of cancer.

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.

Regulation of low-density lipoprotein receptor expression in triple negative breast cancer by EGFR-MAPK signaling

Expression of the low-density lipoprotein receptor (LDLR) has been shown to play a critical role in hypercholesterolemia-associated breast cancer growth and is associated with shorter recurrence-free survival in human breast cancer studies. We sought to identify how circulating LDL cholesterol and tumor LDLR might accelerate oncogenic processes by determining whether increased LDLR expression and cholesterol uptake are associated with the activation of the epidermal growth factor receptor (EGFR) signaling pathway in triple negative breast cancer (TNBC) cell lines. EGF stimulation of MDA-MB-468 (MDA468) cells activated p44/42MAPK (MAPK), increased expression of LDLR, and fluorescent LDL cholesterol uptake. However, stimulation of MDA-MB-231 (MDA231) cells with EGF did not lead to increased expression of LDLR despite inducing phosphorylation of EGFR. Inhibition of MAPK using UO126 in MDA231 cells reduced LDLR expression, and in MDA468 cells, UO126 impaired the LDLR increase in response to EGF. MDA468 cells exposed to the transcription inhibitor, Actinomycin, prior to treatment with EGF showed reduced degradation of LDLR mRNA compared to vehicle-treated cells. Our results suggest that the EGF-associated increase in LDLR protein expression is cell line-specific. The common pathway regulating LDLR expression was MAPK in both TNBC cell lines.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Correlation between Pretreatment Serum Apolipoprotein Level and Prognosis of Small Cell Lung Cancer Patients]

BACKGROUND

Lung cancer is the leading cause of cancer-related death, and small cell lung cancer (SCLC) has a poor prognosis in all types of lung cancer. This study evaluated the relationship between pretreatment serum apolipoprotein levels and prognosis in patients with SCLC, seeks a new index can guide diagnosis and treatment of SCLC.

METHODS

This study retrospectively analyzed the clinical data of 122 patients with SCLC. The clinical results of patients with serum apolipoprotein levels within 2 weeks before treatment were collected, including apolipoprotein AI (ApoA-I), apolipoprotein B (ApoB), and the ratio of apolipoprotein B to apolipoprotein AI (ApoB/ApoA-I). Patients' progression-free survival (PFS) and overall survival (OS) are the main outcome indicators. The best critical to determine the index's value by X-tile tool. For survival analysis, Kaplan-Meier method was used for analysis, and Cox regression analysis method was used for single factor analysis and multifactor analysis.

RESULTS

Compared with patients with low ApoA-I levels, patients with high ApoA-I levels (ApoA-I>1.12 g/L) had better OS (21.5 mon vs 12.3 mon, P=0.007) and PFS (7.3 mon vs 5.5 mon, P=0.017). In contrast, patients with higher ApoB/ApoA-I levels had worse median OS than patients with lower ApoB/ApoA-I levels (13.4 mon vs 20.7 mon, P=0.012). Multivariate Cox regression analysis showed that ApoA-I was an independent prognostic factor affecting PFS in SCLC patients (HR=0.67, 95%CI: 0.45-0.99, P=0.043). ApoB/ApoA-I is an independent risk factor for OS in patients with SCLC (HR=1.98, 95%CI: 1.21-3.23, P=0.007).

CONCLUSIONS

Serum ApoA-I level and ApoB/ApoA-I level before treatment can be important prognostic factors for SCLC, which is helpful to judge the prognosis of patients.

The significances and clinical implications of cholesterol components in human breast cancer

Breast cancer is one the most common malignancies and leading cause of cancer-related mortality in women. Recent studies suggested that hypercholesterolemia may be the potential modifiable risk factors for breast cancer. Cholesterol was well-known for its strong association with cardiovascular disease for long. Moreover, solid evidence has been provided by different studies to illustrate the correlation between lipid and incidence in multiple cancers. Although the conclusion remains controversial or sometimes contrary, which may be due to the multifactorial nature of the disease and the disparity of ethnic population, it is critical to elucidate the relationship between specific cholesterol components in certain population and the exact underlying mechanism of the lipid-associated signaling pathway in breast cancer. The implications of dysregulated lipoproteins as therapeutic targets or options for breast cancer provide novel strategies for us in combating with this malignant disease, which may be achieved by manipulating lipid levels with pharmacological compounds.

PCSK9 and cancer: Rethinking the link

BACKGROUND

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

SEARCH METHODS

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

PURPOSE OF REVIEW

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

The Correlation between Lipid Metabolism Disorders and Prostate Cancer

Prostate cancer is the second most common cancer affecting the male population all over the world. The existence of a correlation between lipid metabolism disorders and cancer of the prostate gland has been widely known for a long time. According to hypotheses, cholesterol may contribute to prostate cancer progression as a result of its participation as a signaling molecule in prostate growth and differentiation via numerous biologic mechanisms including Akt signaling and de novo steroidogenesis. The results of some studies suggest that increased cholesterol levels may be associated with a higher risk of a more aggressive course of the disease. The aforementioned alterations in the synthesis of fatty acids are a unique feature of cancer and, therefore, constitute an attractive target for therapeutic intervention in the treatment of prostate cancer. Pharmacological or gene therapy aims to reduce the activity of enzymes involved in de novo synthesis of fatty acids, FASN, ACLY (ATP citrate lyase) or SCD-1 (Stearoyl-CoA Desaturase) in particular, that may result in cells growth arrest. Nevertheless, not all cancers are unequivocally associated with hypocholesterolaemia. It cannot be ruled out that the relationship between prostate cancer and lipid disorders is not a direct quantitative correlation between carcinogenesis and the amount of circulating cholesterol. Perhaps the correspondence is more sophisticated and connected to the distribution of cholesterol fractions or even sub-fractions of e.g. HDL cholesterol.

Impact of cholesterol-pathways on breast cancer development, a metabolic landscape

ApoB-lipoproteins and their components modulate intracellular metabolism and have been associated with the development of neoplastic phenomena, such as proliferation, anchorage-independent growth, epithelial-mesenchymal transition, and cancer invasion. In cancer cells, the modulation of targets that regulate cholesterol metabolism, such as synthesis de novo, endocytosis, and oxidation, are contributing factors to cancer development. While mechanisms associated with sterol regulatory element-binding protein 2 (SREBP-2)/mevalonate, the low-density lipoprotein receptor (LDL-R) and liver X receptor (LXR) have been linked with tumor growth; metabolites derived from cholesterol-oxidation, such as oxysterols and epoxy-cholesterols, also have been described as tumor processes-inducers. From this notion, we perform an analysis of the role of lipoproteins, their association with intracellular cholesterol metabolism, and the impact of these conditions on breast cancer development, mechanisms that can be shared during atherogenesis promoted mainly by LDL. Pathways connecting plasma dyslipidemias in conjunction with the effect of cholesterol-derived metabolites on intracellular mechanisms and cellular plasticity phenomena could provide new approaches to elucidate the triggering factors of carcinogenesis, conditions that could be considered in the development of new therapeutic approaches.

Identification of a Positive Association between Mammary Adipose Cholesterol Content and Indicators of Breast Cancer Aggressiveness in a French Population

BACKGROUND

Several studies have recently highlighted important roles for adipose tissue in cancer. However, few have examined adipose tissue cholesterol, and no study has been performed in breast adipose tissue associated with breast tumors.

OBJECTIVES

The present work was designed to determine if breast adipose tissue cholesterol from the tumor-surrounding area is associated with breast cancer aggressiveness.

METHODS

Between 2009 and 2011, 215 breast adipose tissue samples were collected at the Tours University Hospital (France) during surgery of women (aged 28-89 y) with invasive breast cancer. Associations of free cholesterol (FC), esterified cholesterol (EC), and total cholesterol (TC) amounts with clinical variables (age, BMI, and treated or untreated hypercholesterolemia) and tumor aggressiveness parameters [phenotype, grade, presence of inflammatory breast cancer (IBC), and multifocality] were tested using Student's t test and after ANOVA.

RESULTS

The predominant form of cholesterol in adipose tissue was FC, and 50% of patients had no detectable EC. The adipose tissue FC content (μg/mg total lipid) was 18% greater in patients >70 y old than in those 40-49 y old (P < 0.05) and the TC content tended to be 12% greater in untreated hypercholesterolemic patients than in normocholesterolemic patients (P = 0.06). Breast adipose cholesterol concentrations were increased in tissues obtained from patients with human-epidermal-growth-factor-receptor-2 (HER2) phenotype (+13% FC; P < 0.05 compared with luminal A), IBC (+15% FC; P = 0.06 compared with noninflammatory tumors), as well as with multifocal triple-negative tumors (+34% FC, P < 0.05; +30% TC, P < 0.05, compared with unifocal triple-negative tumors). Among patients with triple-negative tumors, hypercholesterolemia was significantly more common (P < 0.05) in patients with multifocal tumors (64%) than in patients with unifocal tumors (25%).

CONCLUSIONS

This study is the first of this magnitude that analyzes cholesterol concentrations in adipose tissue from female breast cancer patients. An increase in breast adipose tissue cholesterol content may contribute to breast cancer aggressiveness (HER2 phenotype, multifocality of triple-negative tumors, and IBC).

Influence of cholesterol on cancer progression and therapy

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Abnormality in blood cholesterol level is significantly correlated with risk of different cancers.

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Majority of tumor tissue from cancer patient exhibits overexpression of LDLR and ACAT for supporting rapid cancer cell proliferation.

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Alteration of the cholesterol metabolism in cancer cells hampers therapeutic response.

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Targeting cholesterol metabolism for treatment of cancer with other conventional chemotherapeutic drugs appears to be beneficial.

Cholesterol is a fundamental molecule necessary for the maintenance of cell structure and is vital to various normal biological functions. It is a key factor in lifestyle-related diseases including obesity, diabetes, cardiovascular disease, and cancer. Owing to its altered serum chemistry status under pathological states, it is now being investigated to unravel the mechanism by which it triggers various health complications. Numerous clinical studies in cancer patients indicate an alteration in blood cholesterol level (either decreased or increased) in comparison to normal healthy individuals. This article elaborates on our understanding as to how cholesterol is being hijacked in the malignancy for the development, survival, stemness, progression, and metastasis of cancerous cells. Also, it provides a glimpse of how cholesterol derived entities, alters the signaling pathway towards their advantage. Moreover, deregulation of the cholesterol metabolism pathway has been often reported to hamper various treatment strategies in different cancer. In this context, attempts have been made to bring forth its relevance in being targeted, in pre-clinical and clinical studies for various treatment modalities. Thus, understanding the role of cholesterol and deciphering associated molecular mechanisms in cancer progression and therapy are of relevance towards improvement in the management of various cancers.