Modulation of breast cancer cell adhesion by unsaturated fatty acids

Recent progress in the analysis of unsaturated fatty acids in biological samples by chemical derivatization-based chromatography-mass spectrometry methods

Unsaturated fatty acids (UFAs) are essential fatty acids that execute various biological functions in the human body. Therefore, the qualitative and quantitative analysis of UFAs in biological samples can help to clarify their roles in the occurrence and development of diseases, so to reveal the mechanisms of pathogenesis and potential drug intervention strategies. Chromatography-mass spectrometry is one of the most commonly used techniques for the analysis of UFAs in biological samples. However, due to factors such as the complex structural information of UFAs (the number and specific location of CC double bonds) and the low concentration of UFAs in biological samples, it is still difficult to conduct accurate qualitative and/or quantitative studies of UFAs in complex biological samples. In recent years, the integration and application of chemical derivatization and chromatography-mass spectrometry has been widely used in the detection of UFAs. Based on this overview, we reviewed recent developments and application progress for chemical derivatization-based chromatography-mass spectrometry methods for the qualitative and/or quantitative analysis of UFAs in biological samples over the past ten years. Potential trends for the design and improvement of novel derivatization reagents were proposed.

Infrared spectroscopic imaging study of BV-2 microglia altering tumor cell biological activity and cellular fraction

Tumor brain metastasis is a severe threat to patients' neurological function, in which microglia may be involved in the process of tumor cell metastasis among nerve cells. Our study focused on the interaction between microglia and breast and lung cancer cells. Changes in the proliferation and migration ability of cocultured tumor cells were examined; synchrotron radiation-based fourier transform infrared microspectroscopy (SR-FTIR) was used to detect changes in the structures and contents of biomolecules within the tumor cells. The experimental results showed that the proliferation and migration ability of tumor cells increased after coculture, and the structures and contents of biological macromolecules in tumor cells changed. The absorption peak positions of the amide Ⅱ and amide Ⅰ bands observed for the four kinds of tumor cells changed, and the absorption intensities were significantly enhanced, indicating changes in the secondary structures and contents of proteins in tumor cells, which may be the root cause of the change in tumor cell characteristics. Therefore, the metabolites of microglia may be involved in the progression of tumor cells in the nervous system. In this study, we focused on the interaction between microglia and tumor cells by using SR-FTIR and provided a new understanding of the mechanism of brain metastasis.

Application of metabolomics in the diagnosis of breast cancer: a systematic review

Breast cancer (BC) remains the most frequent type of cancer in females worldwide. However, the pathogenesis of BC is still under the cloud, along with the huge challenge of early diagnosis, which is widely acknowledged as the key to a successful therapy. Metabolomics, a newborn innovative technique in recent years, has demonstrated great potential in cancer-related researches. The aim of this review is to look back on clinical and cellular metabolomic studies in the diagnosis of BC over the past decade, and provide a systematic summary of metabolic biomarkers and pathways related to BC diagnosis.

Metabolomic alterations in invasive ductal carcinoma of breast: A comprehensive metabolomic study using tissue and serum samples

Invasive ductal carcinoma (IDC) is the most common type of breast cancer and the leading cause of breast cancer related mortality. In the present study, metabolomic profiles of 72 tissue samples and 146 serum samples were analysed using targeted liquid chromatography multiple reaction monitoring mass spectrometry (LC-MRM/MS) and untargeted gas chromatography mass spectrometry (GC-MS) approaches. Combination of univariate and multivariate statistical treatment identified significant alterations of 42 and 32 metabolites in tissue and serum samples of IDC, respectively when compared to control. Some of the metabolite changes from tissue were also reflected in serum, indicating a bi-directional interaction of metabolites in IDC. Additionally, 8 tissue metabolites and 9 serum metabolites showed progressive change from control to benign to IDC suggesting their possible role in malignant transformation. We have identified a panel of three metabolites viz. tryptophan, tyrosine, and creatine in tissue and serum, which could be useful in screening of IDC subjects from both control and benign. The metabolomic alterations in IDC showed perturbations in purine and pyrimidine metabolism, amino sugar metabolism, amino acid metabolism, fatty acid biosynthesis etc. Comprehensively, this study provides valuable insights into metabolic adaptations of IDC, which can help to identify diagnostic markers as well as potential therapeutic targets.

A network-based pathway-expanding approach for pathway analysis

Background

Pathway analysis combining multiple types of high-throughput data, such as genomics and proteomics, has become the first choice to gain insights into the pathogenesis of complex diseases. Currently, several pathway analysis methods have been developed to study complex diseases. However, these methods did not take into account the interaction between internal and external genes of the pathway and between pathways. Hence, these approaches still face some challenges. Here, we propose a network-based pathway-expanding approach that takes the topological structures of biological networks into account.

Results

First, two weighted gene-gene interaction networks (tumor and normal) are constructed integrating protein-protein interaction(PPI) information, gene expression data and pathway databases. Then, they are used to identify significant pathways through testing the difference of topological structures of expanded pathways in the two weighted networks. The proposed method is employed to analyze two breast cancer data. As a result, the top 15 pathways identified using the proposed method are supported by biological knowledge from the published literatures and other methods. In addition, the proposed method is also compared with other methods, such as GSEA and SPIA, and estimated using the classification performance of the top 15 expanded pathways.

Conclusions

A novel network-based pathway-expanding approach is proposed to avoid the limitations of existing pathway analysis approaches. Experimental results indicate that the proposed method can accurately and reliably identify significant pathways which are related to the corresponding disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-016-1333-x) contains supplementary material, which is available to authorized users.

Free-radical polymer science structural cancer model: a review

Polymer free-radical lipid alkene chain-growth biological models particularly for hypoxic cellular mitochondrial metabolic waste can be used to better understand abnormal cancer cell morphology and invasive metastasis. Without oxygen as the final electron acceptor for mitochondrial energy synthesis, protons cannot combine to form water and instead mitochondria produce free radicals and acid during hypoxia. Nonuniform bond-length shrinkage of membranes related to erratic free-radical covalent crosslinking can explain cancer-cell pleomorphism with epithelial-mesenchymal transition for irregular membrane borders that "ruffle" and warp over stiff underlying actin fibers. Further, mitochondrial hypoxic conditions produce acid that can cause molecular degradation. Subsequent low pH-activated enzymes then provide paths for invasive cell movement through tissue and eventually blood-born metastasis. Although free-radical crosslinking creates irregularly shaped membranes with structural actin-polymerized fiber extensions as filopodia and lamellipodia, due to rapid cell division the overall cell modulus (approximately stiffness) is lower than normal cells. When combined with low pH-activated enzymes and lower modulus cells, smaller cancer stem cells subsequently have a large advantage to follow molecular destructive pathways and leave the central tumor. In addition, forward structural spike-like lamellipodia protrusions can leverage to force lower-modulus cancer cells through narrow openings. By squeezing and deforming even smaller to allow for easier movement through difficult passageways, cancer cells can travel into adjacent tissues or possibly metastasize through the blood to new tissue.

Characterization of microRNA-125b expression in MCF7 breast cancer cells by ATR-FTIR spectroscopy

MicroRNAs (miRNAs), are ~22 nucleotides long, non-coding RNAs that control gene expression post-transcriptionally by binding to their target mRNA's 3'UTRs (untranslated regions). Due to their roles in various important regulatory processes and pathways, miRNAs have been implicated in disease mechanisms such as tumorigenesis when their expression is deregulated. To date, a significant number of miRNAs and their target messenger RNAs (mRNAs) have been identified and verified. It is generally accepted that miRNAs can potentially bind to many mRNAs, which brings the requirement of validation of these interactions. While understanding that such individual interactions is crucial to delineate the role of a specific miRNA, we took a holistic approach and analyzed global changes in the cell due to expression of a miRNA in a model cell line system. Our model consisted of MCF7 cells stably transfected with miR-125b (MCF7-125b) and empty vector (MCF7-EV). MiR-125b is one of the known down-regulated miRNAs in breast cancers. In this study we examined the global structural changes in MCF7 cells lacking and expressing miR-125b by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy and investigated the dynamic changes by more sensitive spin-labelling Electron Spin Resonance (ESR) spectroscopy. Our results revealed less RNA, protein, lipid, and glycogen content in MCF7-125b compared to MCF7-EV cells. Membrane fluidity and proliferation rate were shown to be lower in MCF7-125b cells. Based on these changes, MCF7-125b and MCF7-EV cells were discriminated successfully by cluster analysis. Here, we provide a novel means to understand the global effects of miRNAs in cells. Potential applications of this approach are not only limited to research purposes. Such a strategy is also promising to pioneer the development of future diagnostic tools for deregulated miRNA expression in patient samples.

Activated leukocyte cell adhesion molecule: a novel biomarker for breast cancer

Activated leukocyte cell adhesion molecule (ALCAM) has been implicated in tumorigenesis. Our goal was to examine the levels of ALCAM, in addition to the classical breast cancer tumor markers carbohydrate antigen 15-3 (CA15-3) and carcinoembryonic antigen (CEA), in serum by quantitative enzyme-linked immunosorbent assay for diagnosis in breast cancer patients. The 3 proteins were measured in serum of 100 healthy women, 50 healthy men and 150 breast carcinoma patients. The diagnostic sensitivity and specificity of the tests were calculated and the association of serum marker concentrations with various clinicopathologic variables was examined using nonparametric Kruskal-Wallis tests. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of the biomarkers. ALCAM, with area under the curve (AUC) of 0.78 [95% CI: 0.73, 0.84] outperformed CA15-3 (AUC = 0.70 [95% CI: 0.64, 0.76]) and CEA (AUC= 0.63 [95% CI: 0.56, 0.70]). The incremental values of AUC for ALCAM over that for CA15-3 were statistically significant (Delong test, p < 0.05). Combining CA15-3 and ALCAM yielded a ROC curve with an AUC of 0.81 (95% CI [0.75, 0.87]). Serum ALCAM appears to be a new biomarker for breast cancer and may have value for disease diagnosis.

The pathology of essential fatty acid deficiency: is it cell adhesion mediated?

For almost 70 years, essential fatty acid deficiency has been known to be associated with skin disorders, vessel abnormalities, and increased tumorigenesis. However, the underlying molecular and cellular mechanism is largely unknown. Recently, it has been reported that essential fatty acids regulate cell adhesion by modifying the expression of cell adhesion molecules. These findings may provide molecular explanations for those phenomena seen in EFAD and this paper aims to discuss these relationships and raise points for further discussion.

Peroxisome proliferator activated receptor-gamma (PPAR-gamma) mediates the action of gamma linolenic acid in breast cancer cells

Gamma linolenic acid (GLA) is a polyunsaturated fatty acid, which induces cytotoxicity and regulates cell adhesion in cancer cells. The molecular mechanism of these actions is not clear. We have shown that GLA acts via peroxisome proliferator activated receptors (PPARs), by stimulating their phosphorylation and translocation to the nucleus. Removing PPAR gamma with antisense oligos abolished the effect of GLA on the expression of adhesion molecules and tumour suppressor genes, whereas removal of PPAR alpha had no effect. Tissues from patients with breast cancer showed a reduction of expression of both PPARs in cancer tissues, as compared with normal. Thus, PPAR gamma serves as the receptor for GLA in the regulation of gene expression in breast cancer cells.

Eicosapentaenoic acid and epidermal growth factor modulation of human breast cancer cell adhesion

Cancer cell adhesion to the subendothelial extracellular matrix (ECM) is an important step in metastasis formation. The effect of epidermal growth factor (EGF) and eicosapentaenoic acid (EPA) on adhesion of the highly metastatic MDA-MB-231 human breast cancer cell line to ECM components was examined in the present study. MDA-MB-231 cells exhibited a dose-dependent decrease in adhesion to Matrigel when treated with EGF. EGF and EPA, alone or in combination, decreased adhesion to Matrigel, fibronectin and type IV collagen. These results suggest that decreased adhesion to ECM substrates by combined EPA and EGF treatment may be the result of a common post-receptor signaling pathway.

Breast cancer: weighing the evidence for a promoting role of dietary fat

It has been hypothesized that a high-fat diet promotes the development of postmenopausal breast cancer. This contention is supported by data showing high international correlations between fat intake and breast cancer rates, modest positive associations with a high-fat diet in case-control studies, and animal model studies that have consistently demonstrated that dietary fat influences mammary cancer development at several stages in the carcinogenic process. A number of plausible biologic mechanisms have been suggested that may explain such promotional effects. In contrast, dietary fat intake is unrelated to the risk of breast cancer in cohort studies. The conflicting findings from cohort studies have created uncertainty regarding nutritional recommendations and breast cancer prevention. After reviewing key scientific findings that are relevant to this issue, the following conclusion is drawn: In the absence of data from dietary intervention trials, the weight of available evidence suggests that the type and amount of fat in the diet is related to postmenopausal breast cancer and that the inability to detect associations within populations (cohort studies) is because of measurement error and the relative homogeneity of diets measured. It is expected that the results from intervention trials will clarify this issue.