Nuclear morphology in breast lesions: refining its assessment to improve diagnostic concordance.

AIMS: Although evaluation of nuclear morphology is important for the diagnosis and categorisation of breast lesions, the criteria used to assess nuclear atypia rely upon the subjective evaluation of several features that may result in inter- and intraobserver variation. This study aims to refine the definitions of cytonuclear features in various breast lesions. METHODS AND RESULTS: ImageJ was used to assess the nuclear morphological features including nuclear diameter, axis length, perimeter, area, circularity and roundness in 160 breast lesions comprising ductal carcinoma in situ (DCIS), invasive breast carcinoma of no special type (IBC-NST), tubular carcinoma, usual ductal hyperplasia (UDH), columnar cell change (CCC) and flat epithelial atypia (FEA). Reference cells included normal epithelial cells, red blood cells (RBCs) and lymphocytes. Reference cells showed size differences not only between normal epithelial cells and RBCs but also between RBCs in varied-sized blood vessels. Nottingham grade nuclear pleomorphism scores 1 and 3 cut-offs in IBC-NST, compared to normal epithelial cells, were < ×1.2 and > ×1.4 that of mean maximum Feret's diameter and < ×1.6 and > ×2.4 that of mean nuclear area, respectively. Nuclear morphometrics were significantly different in low-grade IBC-NST versus tubular carcinoma, low-grade DCIS versus UDH and CCC versus FEA. No differences in the nuclear features between grade-matched DCIS and IBC-NST were identified. CONCLUSION: This study provides a guide for the assessment of nuclear atypia in breast lesions, refines the comparison with reference cells and highlights the potential diagnostic value of image analysis tools in the era of digital pathology.

CD34+ Stromal Cells/Telocytes as a Source of Cancer-Associated Fibroblasts (CAFs) in Invasive Lobular Carcinoma of the Breast.

Several origins have been proposed for cancer-associated fibroblasts (CAFs), including resident CD34+ stromal cells/telocytes (CD34+SCs/TCs). The characteristics and arrangement of mammary CD34+SCs/TCs are well known and invasive lobular carcinoma of the breast (ILC) is one of the few malignant epithelial tumours with stromal cells that can express CD34 or αSMA, which could facilitate tracking these cells. Our objective is to assess whether tissue-resident CD34+SCs/TCs participate in the origin of CAFs in ILCs. For this purpose, using conventional and immunohistochemical procedures, we studied stromal cells in ILCs (n:42) and in normal breasts (n:6, also using electron microscopy). The results showed (a) the presence of anti-CD34+ or anti-αSMA+ stromal cells in varying proportion (from very rare in one of the markers to balanced) around nests/strands of neoplastic cells, (b) a similar arrangement and location of stromal cells in ILC to CD34+SCs/TCs in the normal breast, (c) both types of stromal cells coinciding around the same nest of neoplastic cells and (d) the coexpression of CD34 and αSMA in stromal cells in ILC. In conclusion, our findings support the hypothesis that resident CD34+SCs/TCs participate as an important source of CAFs in ILC. Further studies are required in this regard in other tumours.

Diagnostic performance of peripheral leukocyte telomere G-tail length for detecting breast cancer.

The telomere G-tail (G-tail) plays an essential role in maintaining chromosome stability. In this study, we assessed the leukocyte G-tail length of breast cancer (BC) patients and cancer-free individuals and evaluated the association between the G-tail length and the presence of BC. A significant shortening of the median G-tail length was observed in BC patients compared with cancer-free individuals and was found in the early phase of BC. Our study indicated that the leukocyte G-tail length might be a potential biomarker for BC detection.

Intratumoral heterogeneity of second-harmonic generation scattering from tumor collagen and its effects on metastatic risk prediction.

BACKGROUND: Metastases are the leading cause of breast cancer-related deaths. The tumor microenvironment impacts cancer progression and metastatic ability. Fibrillar collagen, a major extracellular matrix component, can be studied using the light scattering phenomenon known as second-harmonic generation (SHG). The ratio of forward- to backward-scattered SHG photons (F/B) is sensitive to collagen fiber internal structure and has been shown to be an independent prognostic indicator of metastasis-free survival time (MFS). Here we assess the effects of heterogeneity in the tumor matrix on the possible use of F/B as a prognostic tool. METHODS: SHG imaging was performed on sectioned primary tumor excisions from 95 untreated, estrogen receptor-positive, lymph node negative invasive ductal carcinoma patients. We identified two distinct regions whose collagen displayed different average F/B values, indicative of spatial heterogeneity: the cellular tumor bulk and surrounding tumor-stroma interface. To evaluate the impact of heterogeneity on F/B's prognostic ability, we performed SHG imaging in the tumor bulk and tumor-stroma interface, calculated a 21-gene recurrence score (surrogate for OncotypeDX®, or S-ODX) for each patient and evaluated their combined prognostic ability. RESULTS: We found that F/B measured in tumor-stroma interface, but not tumor bulk, is prognostic of MFS using three methods to select pixels for analysis: an intensity threshold selected by a blinded observer, a histogram-based thresholding method, and an adaptive thresholding method. Using both regression trees and Random Survival Forests for MFS outcome, we obtained data-driven prediction rules that show F/B from tumor-stroma interface, but not tumor bulk, and S-ODX both contribute to predicting MFS in this patient cohort. We also separated patients into low-intermediate (S-ODX < 26) and high risk (S-ODX ≥26) groups. In the low-intermediate risk group, comprised of patients not typically recommended for adjuvant chemotherapy, we find that F/B from the tumor-stroma interface is prognostic of MFS and can identify a patient cohort with poor outcomes. CONCLUSIONS: These data demonstrate that intratumoral heterogeneity in F/B values can play an important role in its possible use as a prognostic marker, and that F/B from tumor-stroma interface of primary tumor excisions may provide useful information to stratify patients by metastatic risk.

GANT61 and curcumin-loaded PLGA nanoparticles for GLI1 and PI3K/Akt-mediated inhibition in breast adenocarcinoma.

Current conventional mono and combination therapeutic strategies often fail to target breast cancer tissue effectively due to tumor heterogeneity comprising cancer stem cells (CSCs) and bulk tumor cells. This is further associated with drug toxicity and resistivity in the long run. A nanomedicine platform incorporating combination anti-cancer treatment might overcome these challenges and generate synergistic anti-cancer effects and also reduce drug toxicity. GANT61 and curcumin were co-delivered via polymeric nanoparticles (NPs) for the first time to elicit enhanced anti-tumor activity against heterogeneous breast cancer cell line MCF-7. We adopted the single-emulsion-solvent evaporation method for the preparation of the therapeutic NPs. The GANT61-curcumin PLGA NPs were characterized for their size, shape and chemical properties, and anti-cancer cell studies were undertaken for the plausible explanation of our hypothesis. The synthesized GANT61-curcumin PLGA NPs had a spherical, smooth surface morphology, and an average size of 347.4 d. nm. The NPs induced cytotoxic effects in breast cancer cells at a mid-minimal dosage followed by cell death via autophagy and apoptosis, reduction in their target protein expression along with compromising the self-renewal property of CSCs as revealed by their in vitro cell studies. The dual-drug NPs thus provide a novel perspective on aiding existing anti-cancer nanomedicine therapies to target a heterogeneous tumor mass effectively.

Vitamin D receptor regulates autophagy in the normal mammary gland and in luminal breast cancer cells.

Women in North America have a one in eight lifetime risk of developing breast cancer (BC), and a significant proportion of these individuals will develop recurrent BC and will eventually succumb to the disease. Metastatic, therapy-resistant BC cells are refractory to cell death induced by multiple stresses. Here, we document that the vitamin D receptor (VDR) acts as a master transcriptional regulator of autophagy. Activation of the VDR by vitamin D induces autophagy and an autophagic transcriptional signature in BC cells that correlates with increased survival in patients; strikingly, this signature is present in the normal mammary gland and is progressively lost in patients with metastatic BC. A number of epidemiological studies have shown that sufficient vitamin D serum levels might be protective against BC. We observed that dietary vitamin D supplementation in mice increases basal levels of autophagy in the normal mammary gland, highlighting the potential of vitamin D as a cancer-preventive agent. These findings point to a role of vitamin D and the VDR in modulating autophagy and cell death in both the normal mammary gland and BC cells.

Tumor size and focality in breast carcinoma: Analysis of concordance between radiological imaging modalities and pathological examination at a cancer center.

CONTEXT: Accurate assessment of clinical and pathological tumor stage is crucial for patient treatment and prognosis. OBJECTIVE: The aim of this study was to assess the concordance between the tumor size and focality between radiological studies and pathology and to evaluate the impact of discrepancies on staging. DESIGN: Patients who underwent surgery for invasive breast carcinoma from January 1, 2014, to December 31, 2015, were identified. RESULTS: Three imaging modalities (mammogram, ultrasound and MRI) were compared with gross examination and final pathology. 1152 preoperative radiological studies were evaluated for focality and 1019 were evaluated for tumor size. For all 3 radiographic modalities, there was a statistically significant difference between the mean tumor size on radiology and the final pathology report (mammogram, P < .001; ultrasound, P = .004; MRI, P < .001). In 29% of radiology studies, there was a discrepancy in stage. The error rate for determining focality was 28% for mammograms, 27% for ultrasounds, and 29% for MRIs. Tumor size from gross examination correlated with microscopic tumor size in 57% of cases, but gross examination had 88% concordance with the final pathology report in determining focality. CONCLUSION: Our study revealed statistically significant differences in mean tumor size reported across all 3 imaging modalities when compared to the final pathology report. MRI had the highest error rate, with a tendency to overestimate tumor size and number of foci. Among all diagnoses, cases of invasive carcinoma with an extensive intraductal component were most prone to discrepancies with imaging.

EGFR Expression in HER2-Driven Breast Cancer Cells.

The epidermal growth factor receptor HER2 is overexpressed in 20% of breast cancer cases. HER2 is an orphan receptor that is activated ligand-independently by homodimerization. In addition, HER2 is able to heterodimerize with EGFR, HER3, and HER4. Heterodimerization has been proposed as a mechanism of resistance to therapy for HER2 overexpressing breast cancer. Here, a method is presented for the simultaneous detection of individual EGFR and HER2 receptors in the plasma membrane of breast cancer cells via specific labeling with quantum dot nanoparticles (QDs). Correlative fluorescence microscopy and liquid phase electron microscopy were used to analyze the plasma membrane expression levels of both receptors in individual intact cells. Fluorescent single-cell analysis of SKBR3 breast cancer cells dual-labeled for EGFR and HER2 revealed a heterogeneous expression for receptors within both the cell population as well as within individual cells. Subsequent electron microscopy of individual cells allowed the determination of individual receptors label distributions. QD-labeled EGFR was observed with a surface density of (0.5-5) × 101 QDs/µm2, whereas labeled HER2 expression was higher ranging from (2-10) × 102 QDs/µm2. Although most SKBR3 cells expressed low levels of EGFR, an enrichment was observed at large plasma membrane protrusions, and amongst a newly discovered cellular subpopulation termed EGFR-enriched cells.

Breast Cancer-Derived Exosomes Reflect the Cell-of-Origin Phenotype.

A manner in which cells can communicate with each other is via secreted nanoparticles termed exosomes. These vesicles contain lipids, nucleic acids, and proteins, and are said to reflect the cell-of-origin. However, for the exosomal protein content, there is limited evidence in the literature to verify this statement. Here, proteomic assessment combined with pathway-enrichment analysis is used to demonstrate that the protein cargo of exosomes reflects the epithelial/mesenchymal phenotype of secreting breast cancer cells. Given that epithelial-mesenchymal plasticity is known to implicate various stages of cancer progression, the results suggest that breast cancer subtypes with distinct epithelial and mesenchymal phenotypes may be distinguished by directly assessing the protein content of exosomes. Additionally, the work is a substantial step toward verifying the statement that cell-derived exosomes reflect the phenotype of the cells-of-origin.

An image-based small-molecule screen identifies vimentin as a pharmacologically relevant target of simvastatin in cancer cells.

Vimentin is a cytoskeletal intermediate filament protein that is expressed in mesenchymal cells and cancer cells during the epithelial-mesenchymal transition. The goal of this study was to identify vimentin-targeting small molecules by using the Tocriscreen library of 1120 biochemically active compounds. We monitored vimentin filament reorganization and bundling in adrenal carcinoma SW13 vimentin-positive (SW13-vim+) cells via indirect immunofluorescence. The screen identified 18 pharmacologically diverse hits that included 2 statins-simvastatin and mevastatin. Simvastatin induced vimentin reorganization within 15-30 min and significant perinuclear bundling within 60 min (IC50 = 6.7 nM). Early filament reorganization coincided with increased vimentin solubility. Mevastatin produced similar effects at >1 µM, whereas the structurally related pravastatin and lovastatin did not affect vimentin. In vitro vimentin filament assembly assays revealed a direct targeting mechanism, as determined biochemically and by electron microscopy. In SW13-vim+ cells, simvastatin, but not pravastatin, reduced total cell numbers (IC50 = 48.1 nM) and promoted apoptosis after 24 h. In contrast, SW13-vim- cell viability was unaffected by simvastatin, unless vimentin was ectopically expressed. Simvastatin similarly targeted vimentin filaments and induced cell death in MDA-MB-231 (vim+), but lacked effect in MCF7 (vim-) breast cancer cells. In conclusion, this study identified vimentin as a direct molecular target that mediates simvastatin-induced cell death in 2 different cancer cell lines.-Trogden, K. P., Battaglia, R. A., Kabiraj, P., Madden, V. J., Herrmann, H., Snider, N. T. An image-based small-molecule screen identifies vimentin as a pharmacologically relevant target of simvastatin in cancer cells.

Withaferin-A Inhibits Growth of Drug-Resistant Breast Carcinoma by Inducing Apoptosis and Autophagy, Endogenous Reactive Oxygen Species (ROS) Production, and Inhibition of Cell Migration and Nuclear Factor kappa B (Nf-κB)/Mammalian Target of Rapamycin (m-TOR) Signalling Pathway.

BACKGROUND The main purpose of this study was to assess in vitro and in vivo the anticancer effect of withaferin-A in human breast carcinoma cells (MDA-MB-231), and to assess its effects on autophagy, cell apoptosis, ROS production, cell migration and invasion, and Nf-kappaB/m-TOR signalling pathway. MATERIAL AND METHODS Proliferation of MDA-MB-231 cells at various doses of the drug was studied by CCK8 cell viability assay. Effects on cell apoptosis were studied by fluorescence microscopy in combination with flow cytometry and Western blot analysis. Effects on autophagy were evaluated by transmission electron microscopy and Western blot. Effects on cellular migration were examined in vitro by wound healing assay. RESULTS The results indicated that withaferin-A led to significant reduction of MDA-MB-231 cell viability. The anticancer action of withaferin-A was shown to be due to the stimulation of autophagy, which was accompanied by enhancement of LC3 expression. Withaferin-A prompted mitochondrial apoptosis, which was also associated with increased level of Bax and decreased Bcl-2 in MDA-MB-231 cells. It was also observed that withaferin-A has decreases cellular migration and invasion of the tested human breast cancer cells. The effects of withaferin-A were also investigated in vivo, and it was found that this molecule could inhibit the growth of tumor xenografts in tested mice. Withaferin-A led to suppression of the Nf-kappaB/m-TOR signalling pathway. CONCLUSIONS In brief, the withaferin-A molecule has great potential as an anticancer agent against drug-resistant breast cancer, and as such needs to be further studied in detail.

Core needle biopsy of benign, borderline and in-situ problematic lesions of the breast: Diagnosis, differential diagnosis and immunohistochemistry.

Core needle biopsy (CNB) is the most common sampling technique for the histologic evaluation of breast abnormalities. Diagnosing benign proliferative, borderline and some in-situ lesions in CNB is challenging and subject to a significant degree of interobserver variability. In addition, due to the inherent limitations of CNB, "upgrading" to a more significant pathology at excision is an important consideration for some lesions. Pathologists carry a major responsibility in patient diagnosis, risk stratification and management. Familiarity with the histologic features and the clinical significance of these common and problematic lesions encountered in CNB is necessary for adequate treatment and patient follow-up. This review will focus on benign, atypical and in-situ epithelial proliferations, papillary lesions, radial sclerosing lesions, adenosis and cellular fibroepithelial lesions. Highlights of histologic features, useful strategies for accurate diagnosis, basic immunohistochemistry and management will be presented.

1,3-dimethyl-6-nitroacridine derivatives induce apoptosis in human breast cancer cells by targeting DNA.

The acridine derivatives can interact with the double-stranded DNA, which is regarded as the biological target of the anticancer drugs in cancer treatment. We designed and synthesized a new series of 1,3-dimethyl-6-nitroacridine derivatives as potential DNA-targeted anticancer agents. These compounds could partially intercalate into the calf thymus DNA, differing from the parent acridine. The results showed that the substitutions of the acridine ring had great effect on DNA binding affinity. The binding constants determined by UV-vis spectroscopy were found to be 105 M-1 grade. Anticancer activity of these compounds was screened using MTT assay. Most compounds inhibited 50% cancer cell growth at concentration below 30 µM, the results were consistent with the DNA binding ability. Compounds 1 and 6 were found to have more effective cytotoxicity, especially in human breast cancer cell lines. To investigate the action mechanism, we studied cell apoptosis, morphological changes, and cell cycle distribution in MCF-7 and MDA-MB-231 cells. Compounds 1 and 6 caused MCF-7 and MDA-MB-231 cells death due to apoptosis, and induced cell apoptosis in a dose-dependent manner. They also had significant effect on cell cycle progression and arrested cell cycle at G2/M phase. The results demonstrated that compounds 1 and 6 are promising candidates for cancer treatment.

Goniothalamin Induces Necroptosis and Anoikis in Human Invasive Breast Cancer MDA-MB-231 Cells.

Goniothalamin (GTN) is toxic to several types of cancer cells in vitro. However, its effects on non-apoptotic cell death induction of human cancer cells have been poorly documented. Here, an investigation of the anti-cancer activity of GTN and the molecular signaling pathways of non-apoptotic cell death in the invasive human breast cancer MDA-MB-231 cell line were undertaken. Apoptotic cell death was suppressed by using a pan-caspase inhibitor (Benzyloxycarbonyl-Val-Ala-Asp-[O-methyl]-fluoromethylketone), z-VAD-fmk) as a model to study whether GTN induced caspase-independent cell death. In the anoikis study, MDA-MB-231 cells were cultured on poly-(2-hydroxyethyl methacrylate)- or poly-HEMA- coated plates to mimic anoikis-resistance growth and determine whether GTN induced cell death and the mechanisms involved. GTN and z-VAD-fmk induced human breast cancer MDA-MB-231 cells to undergo necroptosis via endoplasmic reticulum (ER) and oxidative stresses, with increased expressions of necroptotic genes such as rip1, rip3, and mlkl. GTN induced MDA-MB-231 cells to undergo anoikis via reversed epithelial-mesenchymal transition (EMT) protein expressions, inhibited the EGFR/FAK/Src survival signaling pathway, and decreased matrix metalloproteinase secretion.

The significance of tumour microarchitectural features in breast cancer prognosis: a digital image analysis.

BACKGROUND: As only a minor portion of the information present in histological sections is accessible by eye, recognition and quantification of complex patterns and relationships among constituents relies on digital image analysis. In this study, our working hypothesis was that, with the application of digital image analysis technology, visually unquantifiable breast cancer microarchitectural features can be rigorously assessed and tested as prognostic parameters for invasive breast carcinoma of no special type. METHODS: Digital image analysis was performed using public domain software (ImageJ) on tissue microarrays from a cohort of 696 patients, and validated with a commercial platform (Visiopharm). Quantified features included elements defining tumour microarchitecture, with emphasis on the extent of tumour-stroma interface. The differential prognostic impact of tumour nest microarchitecture in the four immunohistochemical surrogates for molecular classification was analysed. Prognostic parameters included axillary lymph node status, breast cancer-specific survival, and time to distant metastasis. Associations of each feature with prognostic parameters were assessed using logistic regression and Cox proportional models adjusting for age at diagnosis, grade, and tumour size. RESULTS: An arrangement in numerous small nests was associated with axillary lymph node involvement. The association was stronger in luminal tumours (odds ratio (OR) = 1.39, p = 0.003 for a 1-SD increase in nest number, OR = 0.75, p = 0.006 for mean nest area). Nest number was also associated with survival (hazard ratio (HR) = 1.15, p = 0.027), but total nest perimeter was the parameter most significantly associated with survival in luminal tumours (HR = 1.26, p = 0.005). In the relatively small cohort of triple-negative tumours, mean circularity showed association with time to distant metastasis (HR = 1.71, p = 0.027) and survival (HR = 1.8, p = 0.02). CONCLUSIONS: We propose that tumour arrangement in few large nests indicates a decreased metastatic potential. By contrast, organisation in numerous small nests provides the tumour with increased metastatic potential to regional lymph nodes. An outstretched pattern in small nests bestows tumours with a tendency for decreased breast cancer-specific survival. Although further validation studies are required before the argument for routine quantification of microarchitectural features is established, our approach is consistent with the demand for cost-effective methods for triaging breast cancer patients that are more likely to benefit from chemotherapy.

Activation of apoptosis in NAF-1-deficient human epithelial breast cancer cells.

Maintaining iron (Fe) ion and reactive oxygen species homeostasis is essential for cellular function, mitochondrial integrity and the regulation of cell death pathways, and is recognized as a key process underlying the molecular basis of aging and various diseases, such as diabetes, neurodegenerative diseases and cancer. Nutrient-deprivation autophagy factor 1 (NAF-1; also known as CISD2) belongs to a newly discovered class of Fe-sulfur proteins that are localized to the outer mitochondrial membrane and the endoplasmic reticulum. It has been implicated in regulating homeostasis of Fe ions, as well as the activation of autophagy through interaction with BCL-2. Here we show that small hairpin (sh)RNA-mediated suppression of NAF-1 results in the activation of apoptosis in epithelial breast cancer cells and xenograft tumors. Suppression of NAF-1 resulted in increased uptake of Fe ions into cells, a metabolic shift that rendered cells more susceptible to a glycolysis inhibitor, and the activation of cellular stress pathways that are associated with HIF1α. Our studies suggest that NAF-1 is a major player in the metabolic regulation of breast cancer cells through its effects on cellular Fe ion distribution, mitochondrial metabolism and the induction of apoptosis.

Morphomechanical and structural changes induced by ROCK inhibitor in breast cancer cells.

The EMT phenomenon is based on tumour progression. The cells lose their physiologic phenotype and assumed a mesenchymal phenotype characterized by an increased migratory capacity, invasiveness and high resistance to apoptosis. In this process, RHO family regulates the activation or suppression of ROCK (Rho-associated coiled-coil containing protein kinase) which in turn regulates the cytoskeleton dynamics. However, while the biochemical mechanisms are widely investigated, a comprehensive and careful estimation of biomechanical changes has not been extensively addressed. In this work, we used a strong ROCK inhibitor, Y-27632, to evaluate the effects of inhibition on living breast cancer epithelial cells by a biomechanical approach. Atomic Force Microscopy (AFM) was used to estimate changes of cellular elasticity, quantified by Young's modulus parameter. The morphometric alterations were analyzed by AFM topographies and Confocal Laser Scanning Microscopy (CLSM). Our study revealed a significant modification in the Young's modulus after treatment, especially as regards cytoskeletal region. Our evidences suggest that the use of Y-27632 enhanced the cell rigidity, preventing cell migration and arrested the metastasization process representing a potential powerful factor for cancer treatment.

Mitochondrial autophagosomes as a mechanism of drug resistance in breast carcinoma.

We have previously described the process by which mitochondria donate their membranes for the formation of autophagosomes, and in this study we show that the same process could be involved in drug sequestration and exocytosis resulting in multidrug-resistant cancerous cells. We examine the implications of mitochondrial vesicle formation of mitoautophagosomes (MAPS) in response to the cytotoxic drug MKT-077, which targets mortalin, in a drug-resistant breast carcinoma cell line overexpressing P-glycoprotein (P-gp). The breast cancer cell line MCF-7Adr is derived from MCF-7, but differs from its ancestral line in tolerance of MKT-077-induced mitochondrial toxicity. Our ultrastructural observations suggest that autophagy in the MCF-7Adr cells entails regional sequestration of MKT077 in multilamellar LC3-labeled MAPS, which then separate from their mitochondria, and fuse with or engulf each other. MAPS appeared to be migrating through the cytoplasm and fusing with the plasma membrane, thus carrying out exocytotic secretion. This mechanism, which seems ineffective in the ancestral cell line, provides a resistance mechanism for MKT-077 by enhancing the efflux process of the cells. After 8 hr of MKT-077 exposure, a fraction of the resistant cells appeared viable and contained larger number of smaller sized mitochondria. Mitoautophagosomes, therefore, provide a potentially novel model for multidrug resistance in cancerous cells and may contribute to the P-gp efflux process.

Cancer-derived extracellular vesicles: the 'soil conditioner' in breast cancer metastasis?

It has been recognized that cancer-associated mortality is more often a result of the disrupted physiological functions in multiple organs following metastatic dissemination of cancer cells, rather than the presence and growth of the primary tumor. Despite advances in our understanding of the events leading to cancer initiation, growth, and acquisition of invasive properties, we are still unable to effectively treat metastatic disease. It is now being accepted that the secretion of extracellular vesicles, such as exosomes from cancer cells, has a profound impact on the initiation and propagation of metastatic breast cancer. These cancer-secreted vesicles differ from other means of cellular communication due to their capability of bulk delivery and organotropism. Here, we provide an overview of the role of extracellular vesicles in breast cancer metastasis and discuss key areas that may facilitate our understanding of metastatic breast cancer to guide our efforts towards providing better therapies.

Fatty acid synthase regulates the chemosensitivity of breast cancer cells to cisplatin-induced apoptosis.

Fatty acid synthase (FASN) is a key enzyme in fat biosynthesis that is over-expressed in advanced breast cancer stages. Cisplatin (CDDP) is a platinum-based drug used in the treatment of certain types of this disease. Although it was shown that FASN inhibition induced apoptosis by enhancing the cytotoxicity of certain drugs in breast cancer, its role in regulating the chemosensitivity of different types of breast cancer cells to CDDP-induced apoptosis is not established yet. Therefore, two different breast cancer cell lines; triple negative breast cancer (TNBC; MDA-MB-231) and triple positive breast cancer (TPBC; BT-474) cells were used to examine such role. We show that TNBC cells had naturally less fat content than TPBC cells. Subsequently, the fat content increased in both cells when treated with Palmitate rather than Oleate, whereas both fatty acids produced apoptotic ultra-structural effects and attenuated FASN expression. However, Oleate increased FASN expression in TPBC cells. CDDP decreased FASN expression and increased apoptosis in TNBC cells. These effects were further enhanced by combining CDDP with fatty acids. We also illustrate that the inhibition of FASN by either siRNA or exogenous inhibitor decreased CDDP-induced apoptosis in TPBC cells suggesting its role as an apoptotic factor, while an opposite finding was observed in TNBC cells when siRNA and fatty acids were used, suggesting its role as a survival factor. To our knowledge, we are the first to demonstrate a dual role of FASN in CDDP-induced apoptosis in breast cancer cells and how it can modulate their chemosensitivity.