Choosing the right cell line for breast cancer research

Resistance of breast cancer cells to paclitaxel is associated with low expressions of miRNA-186 and miRNA-7

Aim: Neo-adjuvant chemotherapy is a common approach for the complex treatment of breast cancer (BC) and paclitaxel (PTX) is frequently included in the therapeutic regimen. However, the effect of PTX-based treatment is hard to predict precisely based on routinely used markers. As microRNAs are considered a new promising class of biomarkers, the link between miRNA expression and PTX resistance of BC cells needs to be well investigated. This study aimed at the identification of miRNAs associated with responses of BC cells to PTX. Methods: Intrinsic PTX sensitivity and miRNA profiling were assayed in five BC cell lines to identify candidate miRNAs. Selected miRNA (n. 15) expressions were analyzed by real-time-quantitative polymerase chain reaction (RT-qPCR) in BC tissue samples (n. 31) obtained from a diagnostic biopsy. Results were analyzed in the context of the effect of two cycles of PTX and the effect of the completed scheme of neoadjuvant therapy. The study's design facilitated the evaluation of the effect of PTX on cells and the identification of features of the microRNA expression profiles associated exclusively with sensitivity to this drug. Results: miR-186 and miR-7 expression in BC tissues was higher in patients with better outcomes of PTX-based neoadjuvant therapy. Conclusion: High expressions of miR-186 and miR-7 are associated with good response to PTX, whereas their low expressions may be associated with resistance to PTX in BC, indicating the possibility of developing innovative test systems for the prediction of the PTX response, which can be used before the start of neo-adjuvant chemotherapy for BC.

Marine Natural Compound (Neviotin A) Displays Anticancer Efficacy by Triggering Transcriptomic Alterations and Cell Death in MCF-7 Cells

We investigated the anticancer mechanism of a chloroform extract of marine sponge (Haliclona fascigera) (sample C) in human breast adenocarcinoma (MCF-7) cells. Viability analysis using MTT and neutral red uptake (NRU) assays showed that sample C exposure decreased the proliferation of cells. Flow cytometric data exhibited reactive oxygen species (ROS), nitric oxide (NO), dysfunction of mitochondrial potential, and apoptosis in sample C-treated MCF-7 cells. A qPCR array of sample C-treated MCF-7 cells showed crosstalk between different pathways of apoptosis, especially BIRC5, BCL2L2, and TNFRSF1A genes. Immunofluorescence analysis affirmed the localization of p53, bax, bcl2, MAPKPK2, PARP-1, and caspase-3 proteins in exposed cells. Bioassay-guided fractionation of sample C revealed Neviotin A as the most active compound triggering maximum cell death in MCF-7, indicating its pharmacological potency for the development of a drug for the treatment of human breast cancer.

F3 peptide functionalized liquid crystalline nanoparticles for delivering Salinomycin against breast cancer

Salinomycin (Sal) is a potent veterinary antibiotic known to offer significant toxicity to the variety of neoplastic cells. Its therapeutic utility is limited due to its higher lipophilicity (logP 7.5) and poor hydrophilicity. Liquid crystalline nanoparticles (LCNPs) known to offer a suitable delivery platform for these kinds of drugs. The overexpressed nucleolin receptor on the cell surface and cytoplasm, could be selected as a target in cancer therapy. The present study involves the development and characterization of the F3 peptide functionalized LCNPs for delivering Sal (F3-Sal-NPs) for selectively targeting to the nucleolin receptor. The optimized LCNPs were characterized for particle size, zeta potential, surface morphology, drug release kinetics and stability. The LCNPs have a structure similar to nematic phases. In vitro drug release studies revealed sustained drug release characteristics (89.5 ± 1.5% at 120 h) with F3-Sal-NPs. The cytotoxicity results demonstrated that F3-Sal-NPs were 4.8, 2.6 and 5.5 folds more effective than naïve drug in MDA-MB-468, MDA-MB-231 and MCF-7 cells, respectively and the cell cycle was arrested in the S and G2/M phases. The expression of the gene responsible for the stemness (CD44 gene), apoptosis (BAX/Bcl-2 ration) and angiogenesis (LCN-2) was reduced by F3-Sal-NPs treatment. Ex vivo hemolytic toxicity was reduced (6.5 ± 1.5%) and the pharmacokinetics and bioavailability of Sal was improved with F3-Sal-NPs. The in vivo antitumor efficacy was tested in EAC bearing mice, where F3-Sal-NPs significantly reduced the tumor growth by 2.8-fold compared to pure Sal and induced necrosis of tumor cells. The results clearly demonstrate the outstanding performance of F3 peptide functionalized LCNPs for delivering Sal against breast cancer.

The Influence of Adipocyte Secretome on Selected Metabolic Fingerprints of Breast Cancer Cell Lines Representing the Four Major Breast Cancer Subtypes

Molecular subtype (MS) is one of the most used classifications of breast cancer (BC). Four MSs are widely accepted according to receptor expression of estrogen, progesterone, and HER2. The impact of adipose tissue on BC MS metabolic impairment is still unclear. The present work aims to elucidate the metabolic alterations in breast cancer cell lines representing different MSs subjected to adipocyte associated factors. Preadipocytes isolated from human subcutaneous adipose tissue were differentiated into mature adipocytes. MS representative cell lines were exposed to mature adipocyte secretome. Extracellular medium was collected for metabolomics and RNA was extracted to evaluate enzymatic expression by RT-PCR. Adipocyte secretome exposure resulted in a decrease in the Warburg effect rate and an increase in cholesterol release. HER2+ cell lines (BT-474 and SK-BR-3) exhibited a similar metabolic pattern, in contrast to luminal A (MCF-7) and triple negative (TN) (MDA-MB-231), both presenting identical metabolisms. Anaplerosis was found in luminal A and TN representative cells, whereas cataplerotic reactions were likely to occur in HER2+ cell lines. Our results indicate that adipocyte secretome affects the central metabolism distinctly in each BC MS representative cell line.

Dual functionalized hyaluronic acid micelles loading paclitaxel for the therapy of breast cancer

Although many carriers for the delivery of chemotherapeutic drugs have been investigated, the disadvantages of passive targeting and uncontrolled drug release limit their utility. Herein, hyaluronic acid (HA) was hydrophobically modified to serve as a carrier for binding to cluster determinant 44 (CD44) overexpressed on tumor cell surfaces. Specifically, after deacetylation, HA was grafted to dodecylamine or tetradecylamine to afford amphiphilic zwitterionic polymer micelles, designated dHAD and dHAT, respectively, for the delivery of paclitaxel (PTX). The micelles were negatively charged at pH 7.4 and positively charged at pH 5.6, and this pH sensitivity facilitated PTX release under acidic conditions. The cell uptake efficiencies of the dHAD-PTX and dHAT-PTX micelles by MCF-7 cells after 4 h of incubation were 96.9% and 95.4%, respectively, and their affinities for CD44 were twice that of HA. Furthermore, the micelles markedly inhibited tumor growth both in vitro and in vivo, with IC50 values of 1.943 μg/mL for dHAD-PTX and 1.874 μg/mL for dHAT-PTX for MCF-7 cells; the tumor inhibition rate of dHAD-PTX (92.96%) was higher than that of dHAT-PTX (78.65%). Importantly, dHAD and dHAT micelles showed negligible systemic toxicity. Our findings suggest that these micelles are promising delivery vehicles for antitumor drugs.

MicroRNA expression profiles associated with the metastatic ability of MDA‑MB‑231 breast cancer cells

Breast cancer is an important worldwide public health concern. The incidence rate of breast cancer increases every year. The primary cause of death is metastasis, a process by which cancer cells spread from a primary site to secondary organs. MicroRNAs (miRs/miRNAs) are small non-coding RNAs that control gene expression at the post-transcriptional level. Dysregulation of certain miRNAs is involved in carcinogenesis, cancer cell proliferation and metastasis. Therefore, the present study assessed miRNAs associated with breast cancer metastasis using two breast cancer cell lines, the low-metastatic MCF-7 and the highly metastatic MDA-MB-231. miRNA array analysis of both cell lines indicated that 46 miRNAs were differentially expressed when compared between the two cell lines. A total of 16 miRNAs were upregulated in MDA-MB-231 compared with MCF-7 cells, which suggested that their expression levels may be associated with the highly invasive phenotype of MDA-MB-231 cells. Among these miRNAs, miR-222-3p was selected for further study and its expression was confirmed by reverse transcription-quantitative PCR (RT-qPCR). Under both non-adherent and adherent culture conditions, the expression levels of miR-222-3p in the MDA-MB-231 cell line were higher than those noted in the MCF-7 cell line under the same conditions. Suppression of endogenous miR-222-3p expression in MDA-MB-231 cells using a miR-222-3p inhibitor resulted in a 20-40% reduction in proliferation, and a ~30% reduction in migration, which suggested that the aggressive phenotype of MDA-MB-231 cells was partly regulated by miR-222-3p. Bioinformatic analysis of miR-222-3p using TargetScan 8.0, miRDB and PicTar identified 25 common mRNA targets, such as cyclin-dependent kinase inhibitor 1B, ADP-ribosylation factor 4, iroquois homeobox 5 and Bcl2 modifying factor. The results of the present study indicated that miR-222-3p was potentially associated with the proliferation and migratory ability of the MDA-MB-231 cell line.

Deconvolution of cancer cell states by the XDec-SM method

Proper characterization of cancer cell states within the tumor microenvironment is a key to accurately identifying matching experimental models and the development of precision therapies. To reconstruct this information from bulk RNA-seq profiles, we developed the XDec Simplex Mapping (XDec-SM) reference-optional deconvolution method that maps tumors and the states of constituent cells onto a biologically interpretable low-dimensional space. The method identifies gene sets informative for deconvolution from relevant single-cell profiling data when such profiles are available. When applied to breast tumors in The Cancer Genome Atlas (TCGA), XDec-SM infers the identity of constituent cell types and their proportions. XDec-SM also infers cancer cells states within individual tumors that associate with DNA methylation patterns, driver somatic mutations, pathway activation and metabolic coupling between stromal and breast cancer cells. By projecting tumors, cancer cell lines, and PDX models onto the same map, we identify in vitro and in vivo models with matching cancer cell states. Map position is also predictive of therapy response, thus opening the prospects for precision therapy informed by experiments in model systems matched to tumors in vivo by cancer cell state.

A GSTP1-mediated lactic acid signaling promotes tumorigenesis through the PPP oxidative branch

Lactic acidosis is a feature of solid tumors and plays fundamental role(s) rendering cancer cells to adapt to diverse metabolic stresses, but the mechanism underlying its roles in redox homeostasis remains elusive. Here we show that G6PD is phosphorylated at tyrosine 249/322 by the SRC through the formation of a GSTP1-G6PD-SRC complex. Lactic acid attenuates this formation and the phosphorylation of G6PD by non-covalently binding with GSTP1. Furthermore, lactic acid increases the activity of G6PD and facilitates the PPP (NADPH production) through its sensor GSTP1, thereby exhibiting resistance to reactive oxygen species when glucose is scarce. Abrogating a GSTP1-mediated lactic acid signaling showed attenuated tumor growth and reduced resistance to ROS in breast cancer cells. Importantly, positive correlations between immuno-enriched SRC protein and G6PD Y249/322 phosphorylation specifically manifest in ER/PR positive or HER negative types of breast cancer. Taken together, these results suggest that GSTP1 plays a key role in tumor development by functioning as a novel lactate sensor.

Assessing the Link between Diabetic Metabolic Dysregulation and Breast Cancer Progression

Diabetes mellitus is a burdensome disease that affects various cellular functions through altered glucose metabolism. Several reports have linked diabetes to cancer development; however, the exact molecular mechanism of how diabetes-related traits contribute to cancer progression is not fully understood. The current study aimed to explore the molecular mechanism underlying the potential effect of hyperglycemia combined with hyperinsulinemia on the progression of breast cancer cells. To this end, gene dysregulation induced by the exposure of MCF7 breast cancer cells to hyperglycemia (HG), or a combination of hyperglycemia and hyperinsulinemia (HGI), was analyzed using a microarray gene expression assay. Hyperglycemia combined with hyperinsulinemia induced differential expression of 45 genes (greater than or equal to two-fold), which were not shared by other treatments. On the other hand, in silico analysis performed using a publicly available dataset (GEO: GSE150586) revealed differential upregulation of 15 genes in the breast tumor tissues of diabetic patients with breast cancer when compared with breast cancer patients with no diabetes. SLC26A11, ALDH1A3, MED20, PABPC4 and SCP2 were among the top upregulated genes in both microarray data and the in silico analysis. In conclusion, hyperglycemia combined with hyperinsulinemia caused a likely unique signature that contributes to acquiring more carcinogenic traits. Indeed, these findings might potentially add emphasis on how monitoring diabetes-related metabolic alteration as an adjunct to diabetes therapy is important in improving breast cancer outcomes. However, further detailed studies are required to decipher the role of the highlighted genes, in this study, in the pathogenesis of breast cancer in patients with a different glycemic index.

Prox1 Suppresses the Proliferation of Breast Cancer Cells via Direct Inhibition of c-Myc Gene Expression

Breast cancer is one of the most lethal malignancies in women worldwide and is characterized by rapid growth and low survival rates, despite advances in tumor biology and therapies. Novel therapeutic approaches require new insights into the molecular mechanisms of malignant transformation and progression. To this end, here, we identified Prox1 as a negative regulator of proliferation and tumor-related metabolism in breast cancer. In particular, we showed that breast tumors from human patients exhibited reduced levels of Prox1 expression, while high expression levels of Prox1 were associated with a favorable prognosis in breast cancer patients. Moreover, we experimentally demonstrated that Prox1 was sufficient to strongly suppress proliferation, migration, and the Warburg effect in human breast cancer cells without inducing apoptosis. Most importantly, over-expression of Prox1 inhibited breast tumor growth in vivo in both heterotopic and orthotopic xenograft mouse models. The anti-tumorigenic effect of Prox1 was mediated by the direct repression of c-Myc transcription and its downstream target genes. Consistently, c-Myc over-expression from an artificial promoter that was not targeted by Prox1 reversed Prox1's anti-tumor effects. These findings suggest that Prox1 has a tumor suppressive role via direct transcriptional regulation of c-Myc, making it a promising therapeutic gene for breast cancer.

Extensive review on breast cancer its etiology, progression, prognostic markers, and treatment

As the most frequent and vulnerable malignancy among women, breast cancer universally manifests a formidable healthcare challenge. From a biological and molecular perspective, it is a heterogenous disease and is stratified based on the etiological factors driving breast carcinogenesis. Notably, genetic predispositions and epigenetic impacts often constitute the heterogeneity of this disease. Typically, breast cancer is classified intrinsically into histological subtypes in clinical landscapes. These stratifications empower physicians to tailor precise treatments among the spectrum of breast cancer therapeutics. In this pursuit, numerous prognostic algorithms are extensively characterized, drastically changing how breast cancer is portrayed. Therefore, it is a basic requisite to comprehend the multidisciplinary rationales of breast cancer to assist the evolution of novel therapeutic strategies. This review aims at highlighting the molecular and genetic grounds of cancer additionally with therapeutic and phytotherapeutic context. Substantially, it also renders researchers with an insight into the breast cancer cell lines as a model paradigm for breast cancer research interventions.

Src stimulates Abl-dependent phosphorylation of the guanine exchange factor Net1A to promote its cytosolic localization and cell motility

The neuroepithelial cell transforming gene 1 (Net1) is a guanine nucleotide exchange factor for the small GTPase RhoA that promotes cancer cell motility and metastasis. Two isoforms of Net1 exist, Net1 and Net1A, both of which are sequestered in the nucleus in quiescent cells to prevent aberrant RhoA activation. Many cell motility stimuli drive cytosolic relocalization of Net1A, but mechanisms controlling this event are not fully understood. Here, we demonstrate that epithelial growth factor stimulates protein kinase Src- and Abl1-dependent phosphorylation of Net1A to promote its cytosolic localization. We show that Abl1 efficiently phosphorylates Net1A on Y373, and that phenylalanine substitution of Y373 prevents Net1A cytosolic localization. Furthermore, we found that Abl1-driven cytosolic localization of Net1A does not require S52, which is a phosphorylation site of a different kinase, c-Jun N-terminal kinase, that inhibits nuclear import of Net1A. However, we did find that MKK7-stimulated cytosolic localization of Net1A does require Y373. We also demonstrate that aspartate substitution at Y373 is sufficient to promote Net1A cytosolic accumulation, and expression of Net1A Y373D potentiates epithelial growth factor-stimulated RhoA activation, downstream myosin light chain 2 phosphorylation, and F-actin accumulation. Moreover, we show that expression of Net1A Y373D in breast cancer cells also significantly increases cell motility and Matrigel invasion. Finally, we show that Net1A is required for Abl1-stimulated cell motility, which is rescued by expression of Net1A Y373D, but not Net1A Y373F. Taken together, this work demonstrates a novel mechanism controlling Net1A subcellular localization to regulate RhoA-dependent cell motility and invasion.

HSD17B4 methylation enhances glucose dependence of BT-474 breast cancer cells and increases lapatinib sensitivity

PURPOSE

HER2-positive breast cancer has a high chance of achieving pathological complete response when HSD17B4, responsible for peroxisomal β-oxidation of very long-chain fatty acids (VLCFA) and estradiol, is methylation-silenced. Here, we aimed to identify the underlying molecular mechanism.

METHODS

Using a HER2-positive breast cancer cell line, BT-474, control and knock-out (KO) clones were obtained. Metabolic characteristics were analyzed using a Seahorse Flux analyzer.

RESULTS

HSD17B4 KO suppressed cellular proliferation, and enhanced sensitivity to lapatinib approximately tenfold. The KO led to accumulation of VLCFA and a decrease of polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and arachidonic acid. HSD17B4 KO increased Akt phosphorylation, possibly via decreased DHA, and genes involved in oxidative phosphorylation (OxPhos) and electron transport chain (ETC) were upregulated. Increased mitochondrial ATP production in the KO cells was confirmed by extracellular flux analyzer. Increased OxPhos led to severe dependence of the KO cells on pyruvate from glycolysis. Suppression of glycolysis by lapatinib led to severe delayed suppression of OxPhos in KO cells.

CONCLUSION

HSD17B4 KO in BT-474 cells caused a decrease of PUFAs, increased Akt phosphorylation, enhanced glucose dependence of OxPhos, and increased sensitivity to inhibition of HER2, upstream of Akt. This mechanism may be applicable to other HER2-positive glucose-dependent breast cancer cells with HSD17B4 silencing.

Primary cancer-associated fibroblasts exhibit high heterogeneity among breast cancer subtypes

Background

Cancer-associated fibroblasts (CAFs) are a diverse subset of cells, that is recently gaining in popularity and have the potential to become a new target for breast cancer (BC) therapy; however, broader research is required to understand their mechanisms and interactions with breast cancer cells. The goal of the study was to isolate CAFs from breast cancer tumour and characterise isolated cell lines. We concentrated on numerous CAF biomarkers that would enable their differentiation.

Materials and methods

Flow cytometry, immunofluorescence, and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) were used to phenotype the primary CAFs.

Results/Conclusions

According to our findings, there was no significant pattern in the classification of cancer-associated fibroblasts. The results of biomarkers expression were heterogeneous, thus no specific subtypes were identified. Furthermore, a comparison of cancer-associated fibroblasts derived from different BC subtypes (luminal A and B, triple-negative, HER2 positive) did not reveal any clear trend of expression.

The Interplay between Atherosclerosis and Cancer: Breast Cancer Cells Increase the Expression of Endothelial Cell Adhesion Markers

Cardiovascular diseases are the leading causes of death worldwide, closely followed by cancer. To investigate the impact of breast cancer cell lines (SKBR3, MCF-7, and MDA-MB-231) on endothelial cell adhesion, a blended medium containing 30% breast-cancer-conditioned medium was prepared. This medium was then exposed to human umbilical vein endothelial cells (HUVECs) and monocytes (THP-1) for 48 h. Homemade oxidized low-density lipoproteins (oxLDL) were optionally added to the blended medium. Immunofluorescence was performed to assess the expression of E-selectin, connexin-43, and ICAM-1 on HUVECs, as well as LOX-1, CD36, and CD162 on THP-1. Additionally, unoxidized LDL was exposed to the three breast cancer cell lines for 48 h, and the formation of oxLDL was quantified. Our results revealed an upregulation of all six adhesion markers involved in the initiation of atherosclerosis when HUVECs and THP-1 were exposed to the breast-cancer-conditioned medium. Furthermore, this expression was further increased by exposure to oxLDL. We also observed a significant elevation in oxLDL levels when LDL was exposed to breast cancer cells. In conclusion, our findings successfully demonstrate an increased LDL oxidation in the presence of breast cancer cells, accompanied by an augmented expression of receptors involved in atherosclerosis initiation. These findings shed new light on the clinically observed interplay between atherosclerosis and cancer.

Hypoxia induced responses are reflected in the stromal proteome of breast cancer

Cancers are often associated with hypoxia and metabolic reprogramming, resulting in enhanced tumor progression. Here, we aim to study breast cancer hypoxia responses, focusing on secreted proteins from low-grade (luminal-like) and high-grade (basal-like) cell lines before and after hypoxia. We examine the overlap between proteomics data from secretome analysis and laser microdissected human breast cancer stroma, and we identify a 33-protein stromal-based hypoxia profile (33P) capturing differences between luminal-like and basal-like tumors. The 33P signature is associated with metabolic differences and other adaptations following hypoxia. We observe that mRNA values for 33P predict patient survival independently of molecular subtypes and basic prognostic factors, also among low-grade luminal-like tumors. We find a significant prognostic interaction between 33P and radiation therapy.

Spatiotemporal quantitative microRNA-155 imaging reports immune-mediated changes in a triple-negative breast cancer model

Introduction

MicroRNAs are small non-coding RNAs and represent key players in physiology and disease. Aberrant microRNA expression is central to the development and progression of cancer, with various microRNAs proposed as potential cancer biomarkers and drug targets. There is a need to better understand dynamic microRNA expression changes as cancers progress and their tumor microenvironments evolve. Therefore, spatiotemporal and non-invasive in vivo microRNA quantification in tumor models would be highly beneficial.

Methods

We developed an in vivo microRNA detector platform in which the obtained signals are positively correlated to microRNA presence, and which permitted stable expression in cancer cells as needed for long-term experimentation in tumor biology. It exploits a radionuclide-fluorescence dual-reporter for quantitative in vivo imaging of a microRNA of choice by radionuclide tomography and fluorescence-based downstream ex vivo tissue analyses. We generated and characterized breast cancer cells stably expressing various microRNA detectors and validated them in vitro.

Results

We found the microRNA detector platform to report on microRNA presence in cells specifically and accurately, which was independently confirmed by real-time PCR and through microRNA modulation. Moreover, we established various breast tumor models in animals with different levels of residual immune systems and observed microRNA detector read-outs by imaging. Applying the detector platform to the progression of a triple-negative breast cancer model, we found that miR-155 upregulation in corresponding tumors was dependent on macrophage presence in tumors, revealing immune-mediated phenotypic changes in these tumors as they progressed.

Conclusion

While applied to immunooncology in this work, this multimodal in vivo microRNA detector platform will be useful whenever non-invasive quantification of spatiotemporal microRNA changes in living animals is of interest.

Molecular Characterization and Landscape of Breast cancer Models from a multi-omics Perspective

Breast cancer is well-known to be a highly heterogenous disease. This facet of cancer makes finding a research model that mirrors the disparate intrinsic features challenging. With advances in multi-omics technologies, establishing parallels between the various models and human tumors is increasingly intricate. Here we review the various model systems and their relation to primary breast tumors using available omics data platforms. Among the research models reviewed here, breast cancer cell lines have the least resemblance to human tumors since they have accumulated many mutations and copy number alterations during their long use. Moreover, individual proteomic and metabolomic profiles do not overlap with the molecular landscape of breast cancer. Interestingly, omics analysis revealed that the initial subtype classification of some breast cancer cell lines was inappropriate. In cell lines the major subtypes are all well represented and share some features with primary tumors. In contrast, patient-derived xenografts (PDX) and patient-derived organoids (PDO) are superior in mirroring human breast cancers at many levels, making them suitable models for drug screening and molecular analysis. While patient derived organoids are spread across luminal, basal- and normal-like subtypes, the PDX samples were initially largely basal but other subtypes have been increasingly described. Murine models offer heterogenous tumor landscapes, inter and intra-model heterogeneity, and give rise to tumors of different phenotypes and histology. Murine models have a reduced mutational burden compared to human breast cancer but share some transcriptomic resemblance, and representation of many breast cancer subtypes can be found among the variety subtypes. To date, while mammospheres and three- dimensional cultures lack comprehensive omics data, these are excellent models for the study of stem cells, cell fate decision and differentiation, and have also been used for drug screening. Therefore, this review explores the molecular landscapes and characterization of breast cancer research models by comparing recent published multi-omics data and analysis.

Effect of Smilax spp. and Phellinus linteus combination on cytotoxicity and cell proliferation of breast cancer cells

BACKGROUND

Although the prevalence of breast cancer (BC) has been reduced in recent years, proficient therapeutic regimens should be further investigated with the aim of further reducing the mortality rate. To obtain more effective treatment, the present study aimed to observe the effects of PL synergistically combined with Smilax corbularia and S. glabra extracts (PSS) on BC cell lines, MCF7, T47D, MDA-MB-231, and MDA-MB-468.

METHODS

The half-maximal inhibition (IC₅₀) concentrations of PSS and PL were determined in a dose- and time-dependent manner using MTT assay. The activity of PSS and PL on anti-BC proliferation was evaluated using BrdU assay, and colony formation assay. Moreover, cell cycle analysis and apoptosis induction as a result of PSS and PL exposure were investigated using propidium iodide (PI) staining and co-staining of annexin V DY634 and PI combined flow cytometric analysis, respectively. Finally, changes in the mRNA expression of genes involved in proliferative and apoptotic pathways (MKI67, HER2, EGFR, MDM2, TNFα, PI3KCA, KRAS, BAX, and CASP8) were explored using RT-qPCR following PSS and PL treatment.

RESULTS

The PSS and PL extracts exhibited significant potential in BC cytotoxicity which were in were in dose- and time-dependent response. This inhibition of cell growth was due to the suppression of cell proliferation, the cell cycle arrest, and the induction of apoptosis. Additionally, an investigation of the underlying molecular mechanism revealed that PSS and PL are involved in downregulation of the MKI67, HER2, EGFR, MDM2, TNFα, and PI3KCA expression.

CONCLUSIONS

This present study has suggested that PSS and PL possess anti-BC proliferative activity mediated via the downregulation of genes participating in the relevant pathways. PSS or PL may be combined with other agents to alleviate the adverse side effects resulted from conventional chemotherapeutic drugs.

The chemokine monocyte chemoattractant protein-1/CCL2 is a promoter of breast cancer metastasis

Breast cancer is the most prevalent cancer worldwide, and metastasis is the leading cause of death in cancer patients. Human monocyte chemoattractant protein-1 (MCP-1/CCL2) was isolated from the culture supernatants of not only mitogen-activated peripheral blood mononuclear leukocytes but also malignant glioma cells based on its in vitro chemotactic activity toward human monocytes. MCP-1 was subsequently found to be identical to a previously described tumor cell-derived chemotactic factor thought to be responsible for the accumulation of tumor-associated macrophages (TAMs), and it became a candidate target of clinical intervention; however, the role of TAMs in cancer development was still controversial at the time of the discovery of MCP-1. The in vivo role of MCP-1 in cancer progression was first evaluated by examining human cancer tissues, including breast cancers. Positive correlations between the level of MCP-1 production in tumors and the degree of TAM infiltration and cancer progression were established. The contribution of MCP-1 to the growth of primary tumors and metastasis to the lung, bone, and brain was examined in mouse breast cancer models. The results of these studies strongly suggested that MCP-1 is a promoter of breast cancer metastasis to the lung and brain but not bone. Potential mechanisms of MCP-1 production in the breast cancer microenvironment have also been reported. In the present manuscript, we review studies in which the role of MCP-1 in breast cancer development and progression and the mechanisms of its production were examined and attempt to draw a consensus and discuss the potential use of MCP-1 as a biomarker for diagnosis.

Physapruin A Exerts Endoplasmic Reticulum Stress to Trigger Breast Cancer Cell Apoptosis via Oxidative Stress

Physalis plants are commonly used traditional medicinal herbs, and most of their extracts containing withanolides show anticancer effects. Physapruin A (PHA), a withanolide isolated from P. peruviana, shows antiproliferative effects on breast cancer cells involving oxidative stress, apoptosis, and autophagy. However, the other oxidative stress-associated response, such as endoplasmic reticulum (ER) stress, and its participation in regulating apoptosis in PHA-treated breast cancer cells remain unclear. This study aims to explore the function of oxidative stress and ER stress in modulating the proliferation and apoptosis of breast cancer cells treated with PHA. PHA induced a more significant ER expansion and aggresome formation of breast cancer cells (MCF7 and MDA-MB-231). The mRNA and protein levels of ER stress-responsive genes (IRE1α and BIP) were upregulated by PHA in breast cancer cells. The co-treatment of PHA with the ER stress-inducer (thapsigargin, TG), i.e., TG/PHA, demonstrated synergistic antiproliferation, reactive oxygen species generation, subG1 accumulation, and apoptosis (annexin V and caspases 3/8 activation) as examined by ATP assay, flow cytometry, and western blotting. These ER stress responses, their associated antiproliferation, and apoptosis changes were partly alleviated by the N-acetylcysteine, an oxidative stress inhibitor. Taken together, PHA exhibits ER stress-inducing function to promote antiproliferation and apoptosis of breast cancer cells involving oxidative stress.

Design, synthesis and evaluation of the anti-breast cancer activity of 1,3-oxazolo[4,5-d]pyrimidine and 1,3-oxazolo[5,4-d]pyrimidine derivatives

A series of 1,3-oxazolo[4,5-d]pyrimidine and 1,3-oxazolo[5,4-d]pyrimidine derivatives were synthesized and functionalized in this study. The obtained compounds were tested against breast cancer cell lines of the NCI subpanel, followed by further analysis using the COMPARE algorithm from the Therapeutics Development Program, NCI. All synthesized derivatives displayed activity against most cell lines in the range of micromolar concentrations in terms of all parameters studied. Oxazolopyrimidine 5 exhibited the highest antitumor activity. A standard COMPARE analysis of the compounds showed that the vectors of the cytotoxic activity of derivatives 10 and 11 displayed a close to very high correlation with tamoxifen, and oxazolopyrimidine 13 displayed a very high correlation with the same drug. Five derivatives (2, 4, 6, 11 and 13) showed a high correlation with aclacinomycin A in the TGI vector. At the same time, compound 1 effectively suppressed ADK in cultured MDA-MB 231 cell lines, indicating that ADK is one of its targets through which it exerts anticancer properties. Based on molecular docking results, the possible binding mode of oxazolopyrimidine 1 to ADK has been suggested.

The ceramide synthase (CERS/LASS) family: Functions involved in cancer progression

INTRODUCTION

Ceramide synthases (CERSes) are also known longevity assurance (LASS) genes. CERSes play important roles in the regulation of cancer progression. The CERS family is expressed in a variety of human tumours and is involved in tumorigenesis. They are closely associated with the progression of liver, breast, cervical, ovarian, colorectal, head and neck squamous cell, gastric, lung, prostate, oesophageal, pancreatic and blood cancers. CERSes play diverse and important roles in the regulation of cell survival, proliferation, apoptosis, migration, invasion, and drug resistance. The differential expression of CERSes in tumour and nontumour cells and survival analysis of cancer patients suggest that some CERSes could be used as potential prognostic markers. They are also important potential targets for cancer therapy.

METHODS

In this review, we summarize the available evidence on the inhibitory or promotive roles of CERSes in the progression of many cancers. Furthermore, we summarize the identified upstream and downstream molecular mechanisms that may regulate the function of CERSes in cancer settings.

The Effect of Cholesterol in MCF7 Human Breast Cancer Cells

In the last decade, cholesterol level has been implicated in several types of cancer, including breast cancer. In the current study, we aimed to investigate the condition of lipid depletion, hypocholesterolemia or hypercholesterolemia reproduced in vitro to analyze the response of different human breast cancer cells. Thus, MCF7 as the luminal A model, MB453 as the HER2 model and MB231 as the triple-negative model were used. No effect on cell growth and viability was detected in MB453 and MB231 cells. In MCF7 cells, hypocholesterolemia (1) reduced cell growth, and Ki67 expression; (2) increased ER/PgR expression; (3) stimulated the 3-Hydroxy-3-Methylglutaryl-CoA reductase and neutral sphingomyelinase and; (4) stimulated the expression of CDKN1A gene coding cyclin-dependent kinase inhibitor 1A protein, GADD45A coding growth arrest and DNA-damage-inducible alpha protein and, PTEN gene coding phosphatase and tensin homolog. All these effects were exacerbated by the lipid-depleted condition and reversed by the hypercholesterolemic condition. The relationship between cholesterol level and sphingomyelin metabolism was demonstrated. In summary, our data suggest that cholesterol levels should be controlled in luminal A breast cancer.

TRAF6 as a potential target in advanced breast cancer: a systematic review, meta-analysis, and bioinformatics validation

TRAF6 has emerged as a key regulator of breast cancer (BCa). However, the TRAF family constitutes of seven members that exhibit distinct and overlapping functions. To explore which TRAF represents a potential druggable target for BCa treatment, we searched Medline, Web of Science and Scopus for relevant studies from inception to June 27, 2021. We identified 14 in vitro, 11 in vivo and 4 human articles. A meta-analysis of pharmacological studies showed that in vitro inhibition of TRAF2/4 (mean difference (MD): - 57.49, 95% CI: - 66.95, - 48.02, P < 0.00001) or TRAF6 (standard(Std.)MD: - 4.01, 95% CI: - 5.75, - 2.27, P < 0.00001) is associated with reduction in BCa cell migration. Consistently, inhibition of TRAF2/4 (MD: - 51.08, 95% CI: - 64.23, - 37.94, P < 0.00001) and TRAF6 (Std.MD: - 2.80, 95% CI: - 4.26, - 1.34, P = 0.0002) is associated with reduced BCa cell invasion, whereas TRAF2/4 inhibition (MD: - 40.54, 95% CI: - 52.83, - 28.26, P < 0.00001) is associated with reduced BCa cell adhesion. Interestingly, only inhibition of TRAF6 (MD: - 21.46, 95% CI: - 30.40, - 12.51, P < 0.00001) is associated with reduced cell growth. In animal models of BCa, administration of pharmacological inhibitors of TRAF2/4 (Std.MD: - 3.36, 95% CI: - 4.53, - 2.18, P < 0.00001) or TRAF6 (Std.MD: - 4.15, 95% CI: - 6.06, - 2.24, P < 0.0001) in mice is associated with reduction in tumour burden. In contrast, TRAF6 inhibitors (MD: - 2.42, 95% CI: - 3.70, - 1.14, P = 0.0002) reduced BCa metastasis. In BCa patients, high expression of TRAF6 (Hazard Ratio: 1.01, CI: 1.01, 1.01, P < 0.00001) is associated with poor survival rate. Bioinformatics validation of clinical and pathway and process enrichment analysis in BCa patients confirmed that gain/amplification of TRAF6 is associated with secondary BCa in bone (P = 0.0079), and poor survival rate (P < 0.05). Overall, TRAF6 inhibitors show promise in the treatment of metastatic BCa. However, low study number and scarcity of evidence from animal and human studies may limit the translation of present findings into clinical practice.

Ginger-Derived 3HDT Exerts Antiproliferative Effects on Breast Cancer Cells by Apoptosis and DNA Damage

Ginger-derived compounds are abundant sources of anticancer natural products. However, the anticancer effects of (E)-3-hydroxy-1-(4'-hydroxy-3',5'-dimethoxyphenyl)-tetradecan-6-en-5-one (3HDT) have not been examined. This study aims to assess the antiproliferation ability of 3HDT on triple-negative breast cancer (TNBC) cells. 3HDT showed dose-responsive antiproliferation for TNBC cells (HCC1937 and Hs578T). Moreover, 3HDT exerted higher antiproliferation and apoptosis on TNBC cells than on normal cells (H184B5F5/M10). By examining reactive oxygen species, mitochondrial membrane potential, and glutathione, we found that 3HDT provided higher inductions for oxidative stress in TNBC cells compared with normal cells. Antiproliferation, oxidative stress, antioxidant signaling, and apoptosis were recovered by N-acetylcysteine, indicating that 3HDT preferentially induced oxidative-stress-mediated antiproliferation in TNBC cells but not in normal cells. Moreover, by examining γH2A histone family member X (γH2AX) and 8-hydroxy-2-deoxyguanosine, we found that 3HDT provided higher inductions for DNA damage, which was also reverted by N-acetylcysteine. In conclusion, 3HDT is an effective anticancer drug with preferential antiproliferation, oxidative stress, apoptosis, and DNA damage effects on TNBC cells.

Clinically Expired Platelet Concentrates as a Source of Extracellular Vesicles for Targeted Anti-Cancer Drug Delivery

The short shelf life of platelet concentrates (PC) of up to 5–7 days leads to higher wastage due to expiry. To address this massive financial burden on the healthcare system, alternative applications for expired PC have emerged in recent years. Engineered nanocarriers functionalized with platelet membranes have shown excellent targeting abilities for tumor cells owing to their platelet membrane proteins. Nevertheless, synthetic drug delivery strategies have significant drawbacks that platelet-derived extracellular vesicles (pEV) can overcome. We investigated, for the first time, the use of pEV as a carrier of the anti-breast cancer drug paclitaxel, considering it as an appealing alternative to improve the therapeutic potential of expired PC. The pEV released during PC storage showed a typical EV size distribution profile (100–300 nm) with a cup-shaped morphology. Paclitaxel-loaded pEV showed significant anti-cancer effects in vitro, as demonstrated by their anti-migratory (>30%), anti-angiogenic (>30%), and anti-invasive (>70%) properties in distinct cells found in the breast tumor microenvironment. We provide evidence for a novel application for expired PC by suggesting that the field of tumor treatment research may be broadened by the use of natural carriers.

OBSCN restoration via OBSCN-AS1 long-noncoding RNA CRISPR-targeting suppresses metastasis in triple-negative breast cancer

Mounting evidence implicates the giant, cytoskeletal protein obscurin (720 to 870 kDa), encoded by the OBSCN gene, in the predisposition and development of breast cancer. Accordingly, prior work has shown that the sole loss of OBSCN from normal breast epithelial cells increases survival and chemoresistance, induces cytoskeletal alterations, enhances cell migration and invasion, and promotes metastasis in the presence of oncogenic KRAS. Consistent with these observations, analysis of Kaplan-Meier Plotter datasets reveals that low OBSCN levels correlate with significantly reduced overall and relapse-free survival in breast cancer patients. Despite the compelling evidence implicating OBSCN loss in breast tumorigenesis and progression, its regulation remains elusive, limiting any efforts to restore its expression, a major challenge given its molecular complexity and gigantic size (~170 kb). Herein, we show that OBSCN-Antisense RNA 1 (OBSCN-AS1), a novel nuclear long-noncoding RNA (lncRNA) gene originating from the minus strand of OBSCN, and OBSCN display positively correlated expression and are downregulated in breast cancer biopsies. OBSCN-AS1 regulates OBSCN expression through chromatin remodeling involving H3 lysine 4 trimethylation enrichment, associated with open chromatin conformation, and RNA polymerase II recruitment. CRISPR-activation of OBSCN-AS1 in triple-negative breast cancer cells effectively and specifically restores OBSCN expression and markedly suppresses cell migration, invasion, and dissemination from three-dimensional spheroids in vitro and metastasis in vivo. Collectively, these results reveal the previously unknown regulation of OBSCN by an antisense lncRNA and the metastasis suppressor function of the OBSCN-AS1/OBSCN gene pair, which may be used as prognostic biomarkers and/or therapeutic targets for metastatic breast cancer.

Patient-Derived Breast Cancer Bone Metastasis In Vitro Model Using Bone-Mimetic Nanoclay Scaffolds

The unavailability of reliable models for studying breast cancer bone metastasis is the major challenge associated with poor prognosis in advanced-stage breast cancer patients. Breast cancer cells tend to preferentially disseminate to bone and colonize within the remodeling bone to cause bone metastasis. To improve the outcome of patients with breast cancer bone metastasis, we have previously developed a 3D in vitro breast cancer bone metastasis model using human mesenchymal stem cells (hMSCs) and primary breast cancer cell lines (MCF-7 and MDAMB231), recapitulating late-stage of breast cancer metastasis to bone. In the present study, we have tested our model using hMSCs and patient-derived breast cancer cell lines (NT013 and NT023) exhibiting different characteristics. We investigated the effect of breast cancer metastasis on bone growth using this 3D in vitro model and compared our results with previous studies. The results showed that NT013 and NT023 cells exhibiting hormone-positive and triple-negative characteristics underwent mesenchymal to epithelial transition (MET) and formed tumors in the presence of bone microenvironment, in line with our previous results with MCF-7 and MDAMB231 cell lines. In addition, the results showed upregulation of Wnt-related genes in hMSCs, cultured in the presence of excessive ET-1 cytokine released by NT013 cells, while downregulation of Wnt-related genes in the presence of excessive DKK-1, released by NT023 cells, leading to stimulation and abrogation of the osteogenic pathway, respectively, ultimately mimicking different types of bone lesions in breast cancer patients.

The Chorioallantoic Membrane Xenograft Assay as a Reliable Model for Investigating the Biology of Breast Cancer

The chorioallantoic membrane (CAM) assay is an alternative in vivo model that allows for minimally invasive research of cancer biology. Using the CAM assay, we investigated phenotypical and functional characteristics (tumor grade, mitosis rate, tumor budding, hormone receptor (HR) and HER2 status, Ki-67 proliferation index) of two breast cancer cell lines, MCF-7 and MDA-MB-231, which resemble the HR+ (luminal) and triple-negative breast cancer (TNBC) subgroups, respectively. Moreover, the CAM results were directly compared with murine MCF-7- and MDA-MB-231-derived xenografts and human patient TNBC tissue. Known phenotypical and biological features of the aggressive triple-negative breast cancer cell line (MDA-MB-231) were confirmed in the CAM assay, and mouse xenografts. Furthermore, the histomorphological and immunohistochemical variables assessed in the CAM model were similar to those in human patient tumor tissue. Given the confirmation of the classical biological and growth properties of breast cancer cell lines in the CAM model, we suggest this in vivo model to be a reliable alternative test system for breast cancer research to reduce murine animal experiments.

Dynamic bioinspired coculture model for probing ER+ breast cancer dormancy in the bone marrow niche

Late recurrences of breast cancer are hypothesized to arise from disseminated tumor cells (DTCs) that reactivate after dormancy and occur most frequently with estrogen receptor-positive (ER⁺) breast cancer cells (BCCs) in bone marrow (BM). Interactions between the BM niche and BCCs are thought to play a pivotal role in recurrence, and relevant model systems are needed for mechanistic insights and improved treatments. We examined dormant DTCs in vivo and observed DTCs near bone lining cells and exhibiting autophagy. To study underlying cell-cell interactions, we established a well-defined, bioinspired dynamic indirect coculture model of ER⁺ BCCs with BM niche cells, human mesenchymal stem cells (hMSCs) and fetal osteoblasts (hFOBs). hMSCs promoted BCC growth, whereas hFOBs promoted dormancy and autophagy, regulated in part by tumor necrosis factor-α and monocyte chemoattractant protein 1 receptor signaling. This dormancy was reversible by dynamically changing the microenvironment or inhibiting autophagy, presenting further opportunities for mechanistic and targeting studies to prevent late recurrence.

Short term starvation potentiates the efficacy of chemotherapy in triple negative breast cancer via metabolic reprogramming

BACKGROUND

Chemotherapy (CT) is central to the treatment of triple negative breast cancer (TNBC), but drug toxicity and resistance place strong restrictions on treatment regimes. Fasting sensitizes cancer cells to a range of chemotherapeutic agents and also ameliorates CT-associated adverse effects. However, the molecular mechanism(s) by which fasting, or short-term starvation (STS), improves the efficacy of CT is poorly characterized.

METHODS

The differential responses of breast cancer or near normal cell lines to combined STS and CT were assessed by cellular viability and integrity assays (Hoechst and PI staining, MTT or H₂DCFDA staining, immunofluorescence), metabolic profiling (Seahorse analysis, metabolomics), gene expression (quantitative real-time PCR) and iRNA-mediated silencing. The clinical significance of the in vitro data was evaluated by bioinformatical integration of transcriptomic data from patient data bases: The Cancer Genome Atlas (TCGA), European Genome-phenome Archive (EGA), Gene Expression Omnibus (GEO) and a TNBC cohort. We further examined the translatability of our findings in vivo by establishing a murine syngeneic orthotopic mammary tumor-bearing model.

RESULTS

We provide mechanistic insights into how preconditioning with STS enhances the susceptibility of breast cancer cells to CT. We showed that combined STS and CT enhanced cell death and increased reactive oxygen species (ROS) levels, in association with higher levels of DNA damage and decreased mRNA levels for the NRF2 targets genes NQO1 and TXNRD1 in TNBC cells compared to near normal cells. ROS enhancement was associated with compromised mitochondrial respiration and changes in the metabolic profile, which have a significant clinical prognostic and predictive value. Furthermore, we validate the safety and efficacy of combined periodic hypocaloric diet and CT in a TNBC mouse model.

CONCLUSIONS

Our in vitro, in vivo and clinical findings provide a robust rationale for clinical trials on the therapeutic benefit of short-term caloric restriction as an adjuvant to CT in triple breast cancer treatment.

Raman Spectroscopy Revealed Cell Passage-Dependent Distinct Biochemical Alterations in Radiation-Resistant Breast Cancer Cells

Recapitulating radioresistant cell features in pertinent cell line models is essential for deciphering fundamental cellular mechanisms. The limited understanding of passage and cell cycle phases on radioresistant cells revived post-cryopreservation led us to investigate the effect of sub-culturing in parental and radioresistant MCF-7 cells. In this study, the radioresistant cells showed high-intensity nucleic acid and cytochrome bands, which are potentially a radiation-induced spectral marker. Raman spectroscopy data showed dynamic biochemical alterations in revived radioresistant G₂/M synchronized cells at early cell passages 1 and 3 with stabilization at a latter cell passage, 5. The study highlights the importance of cell passaging and cell cycle phases in potentially changing the biochemical parameters during in vitro experiments after the revival of radioresistant cells post-cryopreservation.

Epigenetic alterations impede epithelial-mesenchymal transition by modulating centrosome amplification and Myc/RAS axis in triple negative breast cancer cells

Alterations in centrosome proteins may result in centrosome abnormalities such as disorganized spindles and centrosome amplification, leading to aneuploidy and genomic instability. Centrosomes exhibit unique epigenetic properties in which structural or positional information is propagated through somatic lineage by non-genetic pathways. Excessive centrosome amplification in breast cancer is accompanied by efficient clustering and loss of E-cadherin, indicating an important adaptive mechanism of cancer. This study sought to elucidate the effect of epigenetic alterations on centrosome amplification, epithelial-mesenchymal transition (EMT) and apoptosis in triple negative human breast adenocarcinoma derived MDA-MB-231 cell line. The results obtained here show that siRNA mediated silencing of DNMT1 and specific inhibition of HDAC1 & HDAC2 by Tricostatin A (TSA) synergistically inhibit cell proliferation through modulation of centrosome proteins γ-tubulin, TUBGCP2 and pericentrin. In addition, induction of apoptosis was observed by downregulation of Bcl2, upregulation of Bax and activation of PARP cleavage. Inhibition of EMT was confirmed through upregulation of E-cadherin and downregulation of N-cadherin and vimentin. Similarly, downregulation of Myc, RAS and CDK2, which plays important roles in proliferation and survival, was observed. Nuclear protein analysis revealed downregulation in the nuclear translocation of E2F1, which regulates centrosome amplification and metastasis in breast cancer. In conclusion, this study confirmed the role of epigenetic regulators in centrosome amplification and suggests that inhibition of DNA methylation and histone deacetylation-mediated chromatin remodelling synergistically disrupt EMT through modulation of centrosome amplification and Myc/RAS axis to potentiate apoptosis and attenuate cell proliferation in triple negative breast cancer cells.

The synthetic molecule stauprimide impairs cell growth and migration in triple-negative breast cancer

Stauprimide, a semi-synthetic derivative of staurosporine, is known mainly for its potent differentiation-enhancing properties in embryonic stem cells. Here, we studied the effects of stauprimide in cell growth and migration of triple-negative breast cancer cells in vitro, evaluating its potential antitumoral activity in an orthotopic mouse model of breast cancer in vivo. Our results from survival curves, EdU incorporation, cell cycle analysis and annexin-V detection in MDA-MB-231 cells indicated that stauprimide inhibited cell proliferation, arresting cell cycle in G₂/M without induction of apoptosis. A decrease in the migratory capability of MDA-MB-231 was also assessed in response to stauprimide. In this work we pointed to a mechanism of action of stauprimide involving the modulation of ERK1/2, Akt and p38 MAPK signalling pathways, and the downregulation of MYC in MDA-MB-231 cells. In addition, orthotopic MDA-MB-231 xenograft and 4T1 syngeneic models suggested an effect of stauprimide in vivo, increasing the necrotic core of tumors and reducing metastasis in lung and liver of mice. Together, our results point to the promising role of stauprimide as a putative therapeutic agent in triple-negative breast cancer.

The role played by ailanthone in inhibiting bone metastasis of breast cancer by regulating tumor-bone microenvironment through the RANKL-dependent pathway

Introduction: Bone metastasis of breast cancer (BC) is a process in which the disruption of the bone homeostatic microenvironment leads to an increase in osteoclast differentiation. Ailanthus altissima shows an inhibitory effect on osteoclast differentiation. Ailanthone (AIL) refers to a natural compound isolated from Ailanthus altissima, a Chinese herbal medicine, and has effective anti-tumor activity in numerous cell lines. Its impact on bone metastases for BC is yet unclear. Methods: We measured the effect of AIL on MDA-MB-231 cells by wound healing experiments, Transwell and colony formation experiment. Using the Tartrate-resistant Acid Phosphatase (TRAP) staining tests, filamentous (F-actin) staining and bone resorption test to detect the effect of AIL on the osteoclast cell differentiation of the Bone Marrow-derived Macrophages (BMMs), activated by the MDA-MB-231 cell Conditioned Medium (MDA-MB-231 CM) and the Receptor Activator of Nuclear factor-κB Ligand (RANKL),and to explore its possibility Mechanisms. In vivo experiments verified the effect of AIL on bone destruction in breast cancer bone metastasis model mice. Results: In vitro, AIL significantly decrease the proliferation, migration and infiltration abilities of MDA-MB-231 cells at a safe concentration, and also reduced the expression of genes and proteins involved in osteoclast formation in MDA-MB-231 cells. Osteoclast cell differentiation of the BMMs, activated by MDA-MB-231 CM and RANKL, were suppressed by AIL in the concentration-dependent manner. Additionally, it inhibits osteoclast-specific gene and protein expression. It was noted that AIL inhibited the expression of the osteoclast differentiation-related cytokines RANKL and interleukin-1β (IL-1β) that were secreted by the MDA-MB-231 cells after upregulating the Forkhead box protein 3 (FOXP3) expression. Furthermore, AIL also inhibits the expression of the Mitogen-Activated Protein Kinase (MAPK), Phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT), and Nuclear factor-κB Ligand (NF-κB) signaling pathways, which then suppresses the MDA-MB-231CM-induced development of Osteoclasts. Conclusion: Our study shows that AIL blocks osteoclast differentiation in the bone metastasis microenvironment by inhibiting cytokines secreted by BC cells, which may be a potential agent for the treatment of BC and its secondary bone metastasis.

The Role of Mesenchymal Stem Cells in Modulating the Breast Cancer Microenvironment

The role of mesenchymal stem cells (MSCs) in the breast tumor microenvironment (TME) is significant and multifaceted. MSCs are recruited to breast tumor sites through molecular signals released by tumor sites. Once in the TME, MSCs undergo polarization and interact with various cell populations, including immune cells, cancer-associated fibroblasts (CAFs), cancer stem cells (CSCs), and breast cancer cells. In most cases, MSCs play roles in breast cancer therapeutic resistance, but there is also evidence that indicates their abilities to sensitize cancer cells to chemotherapy and radiotherapy. MSCs possess inherent regenerative and homing properties, making them attractive candidates for cell-based therapies. Therefore, MSCs can be engineered to express therapeutic molecules or deliver anti-cancer agents directly to tumor sites. Unraveling the intricate relationship between MSCs and the breast TME has the potential to uncover novel therapeutic targets and advance our understanding of breast cancer biology.

Growth and invasion inhibition of T47D ductal carcinoma cells by the association of docetaxel with a bioactive agent in neutral nanosuspension

Introduction: The approach for drug delivery has impressively developed with the emergence of nanosuspension, particularly the targeted nanoemulsions (NEs). It can potentially improve the bioavailability of drugs, enhancing their therapeutic efficiency. This study aims to examine the potential role of NE as a delivery system for the combination of docetaxel (DTX), a microtubule-targeting agent, and thymoquinone (TQ) in the treatment of human ductal carcinoma cells T47D. Methods: NEs were synthesized by ultra-sonication and characterized physically by dynamic light scattering (DLS). A sulforhodamine B assay was performed to evaluate cytotoxicity, and a flow cytometry analysis for cell cycle, apoptosis, autophagy, and cancer stem cell evaluations. A quantitative polymerase chain reaction further assessed the epithelial-mesenchymal transition gene expirations of SNAIL-1, ZEB-1, and TWIST-1. Results: The optimal sizes of blank-NEs and NE-DTX+TQ were found at 117.3 ± 8 nm and 373 ± 6.8 nm, respectively. The synergistic effect of the NE-DTX+TQ formulation significantly inhibited the in vitro proliferation of T47D cells. It caused a significant increase in apoptosis, accompanied by the stimulation of autophagy. Moreover, this formulation arrested T47D cells at the G₂/M phase, promoted the reduction of the breast cancer stem cell (BCSC) population, and repressed the expression of TWIST-1 and ZEB-1. Conclusion: Co-delivery of NE-DTX+TQ may probably inhibit the proliferation of T47D via the induction of apoptosis and autophagy pathways and impede the migration by reducing the BCSC population and downregulating TWIST-1 expression to decrease the epithelial-to-mesenchymal transition (EMT) of breast cancer cells. Therefore, the study suggests the NE-DTX+TQ formula as a potential approach to inhibit breast cancer growth and metastasis.

Validation of a 3D perfused cell culture platform as a tool for humanised preclinical drug testing in breast cancer using established cell lines and patient-derived tissues

3D cell culture models of cancer are currently being developed to recapitulate in vivo physiological conditions and to assess therapeutic responses. However, most models failed to incorporate the biochemical and biophysical stimuli from fluid flow. In this study, a three-dimensional scaffold, SeedEZ was applied within the PerfusionPal perfused culture system to investigate how perfusion, and blood-like oxygen delivery influenced breast cancer cell growth and their responses to a commonly used breast cancer drug tamoxifen. Our results showed that breast cancer cells could be maintained over 3 weeks in PerfusionPal with increased cell viability compared to static 3D culture in fully humanised conditions. This platform also supported examining the effect of tamoxifen on breast cancer cell lines and in primary patient-derived breast cancer samples. Future work is warranted to further the adaption for fully humanised assessment of drug effectiveness in a patient personalized approach with the aim to reduce the burden of animal use in cancer research and increase the degree of human pre-clinical data translation to clinic.

Zinc finger and SCAN domain containing 1, ZSCAN1, is a novel stemness-related tumor suppressor and transcriptional repressor in breast cancer targeting TAZ

Introduction

Cancer stem cells (CSCs) targeted therapy holds the potential for improving cancer management; identification of stemness-related genes in CSCs is necessary for its development.

Methods

The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets were used for survival analysis. ZSCAN1 correlated genes was identified by Spearman correlation analysis. Breast cancer stem-like cells (BCSLCs) were isolated by sorting CD44+CD24- cells from suspension cultured breast cancer (BC) spheroids. The sphere-forming capacity and sphere- and tumor-initiating capacities were determined by sphere formation and limiting dilution assays. The relative gene expression was determined by qRT-PCR, western blot. Lentivirus system was used for gene manipulation. Nuclear run-on assay was employed to examine the levels of nascent mRNAs. DNA pull-down and Chromatin immunoprecipitation (ChIP) assays were used for determining the interaction between protein and target DNA fragments. Luciferase reporter assay was used for evaluating the activity of the promoter.

Results and discussion

ZSCAN1 is aberrantly suppressed in BC, and this suppression indicates a bad prognosis. Ectopic expression of ZSCAN1 inhibited the proliferation, clonogenicity, and tumorigenicity of BC cells. ZSCAN1-overexpressing BCSLCs exhibited weakened stemness properties. Normal human mammary epithelial (HMLE) cells with ZSCAN1 depletion exhibited enhanced stemness properties. Mechanistic studies showed that ZSCAN1 directly binds to -951 ~ -925bp region of WWTR1 (encodes TAZ) promoter, inhibits WWTR1 transcription, thereby inhibiting the stemness of BCSCs. Our work thus revealed ZSCAN1 as a novel stemness-related tumor suppressor and transcriptional repressor in BC.

Mitochondrial calcium uniporter activates TFEB-driven autophagy to promote migration of breast cancer cells

Objectives

Tumor metastasis is the leading cause of death in breast cancer (BC) patients and is a complicated process. Mitochondrial calcium uniporter (MCU), a selective channel responsible for mitochondrial Ca2+ uptake, has been reported to be associated with tumorigenesis and metastasis. The molecular mechanisms of MCU contributing to the migration of BC cells are partially understood. This study investigated the role of MCU in BC cell metastasis and explored the underlying mechanism of MCU-mediated autophagy in BC cell migration.

Materials and Methods

The Kaplan-Meier plotter database was used to analyze the prognostic value of MCU mRNA expression. Western blotting was used to examine the expression level of MCU in 4 paired BC and adjacent normal tissues. The cellular migration capability of BC was measured by transwell migration assay and wound healing assay. Western blotting and reverse transcription-quantitative polymerase chain reaction were performed to detect the expression levels of autophagy-related markers. The effects of MCU activation or inhibition on TFEB nuclear translocation in BC cells were detected by laser scanning confocal microscopy.

Results

Expression of MCU was found to be negatively correlated with BC patient prognosis in the Kaplan-Meier plotter database. Compared with the adjacent normal tissues, MCU was markedly up-regulated in the BC tissues. MCU overexpression promoted cellular migration, activated autophagy, and increased TFEB nuclear translocation in BC cells, whereas its knockdown produced the opposite effects.

Conclusion

MCU activates TFEB-driven autophagy to promote BC cell metastasis and provides a potential novel therapeutic target for BC clinical intervention.

The role of activated androgen receptor in cofilin phospho-regulation depends on the molecular subtype of TNBC cell line and actin assembly dynamics

Triple negative breast cancer (TNBC) is highly metastatic and of poor prognosis. Metastasis involves coordinated actin filament dynamics mediated by cofilin and associated proteins. Activated androgen receptor (AR) is believed to contribute to TNBC tumorigenesis. Our current work studied roles of activated AR and cofilin phospho-regulation during migration of three AR+ TNBC cell lines to determine if altered cofilin regulation can explain their migratory differences. Untreated or AR agonist-treated BT549, MDA-MB-453, and SUM159PT cells were compared to cells silenced for cofilin (KD) or AR expression/function (bicalutamide). Cofilin-1 was found to be the only ADF/cofilin isoform expressed in each TNBC line. Despite a significant increase in cofilin kinase caused by androgens, the ratio of cofilin:p-cofilin (1:1) did not change in SUM159PT cells. BT549 and MDA-MB-453 cells contain high p-cofilin levels which underwent androgen-induced dephosphorylation through increased cofilin phosphatase expression, but surprisingly maintain a leading-edge with high p-cofilin/total cofilin not found in SUM159PT cells. Androgens enhanced cell polarization in all lines, stimulated wound healing and transwell migration rates and increased N/E-cadherin mRNA ratios while reducing cell adhesion in BT549 and MDA-MB-453 cells. Cofilin KD negated androgen effects in MDA-MB-453 except for cell adhesion, while in BT549 cells it abrogated androgen-reduced cell adhesion. In SUM159PT cells, cofilin KD with and without androgens had similar effects in almost all processes studied. AR dependency of the processes were confirmed. In conclusion, cofilin regulation downstream of active AR is dependent on which actin-mediated process is being examined in addition to being cell line-specific. Although MDA-MB-453 cells demonstrated some control of cofilin through an AR-dependent mechanism, other AR-dependent pathways need to be further studied. Non-cofilin-dependent mechanisms that modulate migration of SUM159PT cells need to be investigated. Categorizing TNBC behavior as AR responsive and/or cofilin dependent can inform on decisions for therapeutic treatment.

Bibliometric analysis on exploitation of biogenic gold and silver nanoparticles in breast, ovarian and cervical cancer therapy

Multifunctional nanoparticles are being formulated to overcome the side effects associated with anticancer drugs as well as conventional drug delivery systems. Cancer therapy has gained the advancement due to various pragmatic approaches with better treatment outcomes. The metal nanostructures such as gold and silver nanoparticles accessible via eco-friendly method provide amazing characteristics in the field of diagnosis and therapy towards cancer diseases. The environmental friendly approach has been proposed as a substitute to minimize the use of hazardous compounds associated in chemical synthesis of nanoparticles. In this attempt, researchers have used various microbes, and plant-based agents as reducing agents. In the last 2 decades various papers have been published emphasizing the benefits of the eco-friendly approach and advantages over the traditional method in the cancer therapy. Despite of various reports and published research papers, eco-based nanoparticles do not seem to find a way to clinical translation for cancer treatment. Present review enumerates the bibliometric data on biogenic silver and gold nanoparticles from Clarivate Analytics Web of Science (WoS) and Scopus for the duration 2010 to 2022 for cancer treatment with a special emphasis on breast, ovarian and cervical cancer. Furthermore, this review covers the recent advances in this area of research and also highlights the obstacles in the journey of biogenic nanodrug from clinic to market.

Marine Sponge Aaptos suberitoides Extract Improves Antiproliferation and Apoptosis of Breast Cancer Cells without Cytotoxicity to Normal Cells In Vitro

The anticancer effects and mechanisms of marine sponge Aaptos suberitoides were rarely assessed, especially for methanol extract of A. suberitoides (MEAS) to breast cancer cells. This study evaluated the differential suppression effects of proliferation by MEAS between breast cancer and normal cells. MEAS demonstrated more antiproliferation impact on breast cancer cells than normal cells, indicating oxidative stress-dependent preferential antiproliferation effects on breast cancer cells but not for normal cells. Several oxidative stress-associated responses were highly induced by MEAS in breast cancer cells but not normal cells, including the generations of cellular and mitochondrial oxidative stress as well as the depletion of mitochondrial membrane potential. MEAS downregulated cellular antioxidants such as glutathione, partly contributing to the upregulation of oxidative stress in breast cancer cells. This preferential oxidative stress generation is accompanied by more DNA damage (γH2AX and 8-hydroxy-2-deoxyguanosine) in breast cancer cells than in normal cells. N-acetylcysteine reverted these MEAS-triggered responses. In conclusion, MEAS is a potential natural product for treating breast cancer cells with the characteristics of preferential antiproliferation function without cytotoxicity to normal cells in vitro.

Deep learning-based multi-drug synergy prediction model for individually tailored anti-cancer therapies

While synergistic drug combinations are more effective at fighting tumors with complex pathophysiology, preference compensating mechanisms, and drug resistance, the identification of novel synergistic drug combinations, especially complex higher-order combinations, remains challenging due to the size of combination space. Even though certain computational methods have been used to identify synergistic drug combinations in lieu of traditional in vitro and in vivo screening tests, the majority of previously published work has focused on predicting synergistic drug pairs for specific types of cancer and paid little attention to the sophisticated high-order combinations. The main objective of this study is to develop a deep learning-based approach that integrated multi-omics data to predict novel synergistic multi-drug combinations (DeepMDS) in a given cell line. To develop this approach, we firstly created a dataset comprising of gene expression profiles of cancer cell lines, target information of anti-cancer drugs, and drug response against a large variety of cancer cell lines. Based on the principle of a fully connected feed forward Deep Neural Network, the proposed model was constructed using this dataset, which achieved a high performance with a Mean Square Error (MSE) of 2.50 and a Root Mean Squared Error (RMSE) of 1.58 in the regression task, and gave the best classification accuracy of 0.94, an area under the Receiver Operating Characteristic curve (AUC) of 0.97, a sensitivity of 0.95, and a specificity of 0.93. Furthermore, we utilized three breast cancer cell subtypes (MCF-7, MDA-MD-468 and MDA-MB-231) and one lung cancer cell line A549 to validate the predicted results of our model, showing that the predicted top-ranked multi-drug combinations had superior anti-cancer effects to other combinations, particularly those that were widely used in clinical treatment. Our model has the potential to increase the practicality of expanding the drug combinational space and to leverage its capacity to prioritize the most effective multi-drug combinational therapy for precision oncology applications.

Establishment of triple-negative breast cancer cells based on BMI: A novel model in the correlation between obesity and breast cancer

Introduction

Obesity has been associated with an increased risk of biologically aggressive variants in breast cancer. Women with obesity often have tumors diagnosed at later stages of the disease, associated with a poorer prognosis and a different response to treatment. Human cell lines have been derived from specific subtypes of breast cancer and have served to define the cell physiology of corresponding breast cancer subtypes. However, there are no current cell lines for breast cancer specifically derived from patients with different BMIs. The availability of those breast cancer cell lines should allow to describe and unravel functional alterations linked to these comorbidities.

Methods

Cell cultures were established from tumor explants. Once generated, the triple negative subtype in a patient with obesity and a patient with a normal BMI were chosen for comparison. For cellular characterization, the following assays were conducted: proliferation assays, chemo - sensitivity assays for doxorubicin and paclitaxel, wound healing motility assays, matrix invasion assays, breast cancer cell growth to estradiol by chronic exposure to leptin, induction of endothelial permeability and tumorigenic potential in athymic mice with normo - versus hypercaloric diets with an evaluation of the epithelium - mesenchymal transformation proteins.

Results

Two different cell lines, were established from patients with breast cancer: DSG-BC1, with a BMI of 21.9 kg/m2 and DSG-BC2, with a BMI of 31.5 kg/m2. In vitro, these two cell lines show differential growth rates, motility, chemosensitivity, vascular permeability, response to leptin with an activation of the JAK2/STAT3/AKT signaling pathway. In vivo, they displayed distinct tumorigenic potential. In particular, DSG-BC2, presented higher tumorigenicity when implanted in mice fed with a hypercaloric diet.

Discussion

To our knowledge, these primary cultures are the first in vitro representation of both breast cancer and obesity. DSG - BC2 presented a more aggressive in vivo and in vitro phenotype. These results support the hypothesis that breast cancer generated in an obese metabolic state may represent a contrasting variant within the same disease. This new model will allow both further comprehension, functional studies and the analysis of altered molecular mechanisms under the comorbidity of obesity and breast cancer.

Semi-Synthetic Click-Gelatin Hydrogels as Tunable Platforms for 3D Cancer Cell Culture

Basement membrane extracts (BME) derived from Engelbreth-Holm-Swarm (EHS) mouse sarcomas such as Matrigel^® remain the gold standard extracellular matrix (ECM) for three-dimensional (3D) cell culture in cancer research. Yet, BMEs suffer from substantial batch-to-batch variation, ill-defined composition, and lack the ability for physichochemical manipulation. Here, we developed a novel 3D cell culture system based on thiolated gelatin (Gel-SH), an inexpensive and highly controlled raw material capable of forming hydrogels with a high level of biophysical control and cell-instructive bioactivity. We demonstrate the successful thiolation of gelatin raw materials to enable rapid covalent crosslinking upon mixing with a synthetic poly(ethylene glycol) (PEG)-based crosslinker. The mechanical properties of the resulting gelatin-based hydrogels were readily tuned by varying precursor material concentrations, with Young's moduli ranging from ~2.5 to 5.8 kPa. All hydrogels of varying stiffnesses supported the viability and proliferation of MDA-MB-231 and MCF-7 breast cancer cell lines for 14 and 21 days of cell culture, respectively. Additionally, the gelatin-based hydrogels supported the growth, viability, and osteogenic differentiation of patient-derived preosteoblasts over 28 days of culture. Collectively, our data demonstrate that gelatin-based biomaterials provide an inexpensive and tunable 3D cell culture platform that may overcome the limitations of traditional BMEs.

Genome-wide differential DNA methylation analysis of MDA-MB-231 breast cancer cells treated with curcumin derivatives, ST08 and ST09

ST08 and ST09 are potent curcumin derivatives with antiproliferative, apoptotic, and migrastatic properties. Both ST08 and ST09 exhibit in vitro and in vivo anticancer properties. As reported earlier, these derivatives were highly cytotoxic towards MDA-MB-231 triple-negative breast cancer cells with IC50 values in the nanomolar (40-80nM) range.In this study,we performed whole-genome bisulfite sequencing(WGBS) of untreated (control), ST08 and ST09 (treated) triple-negative breast cancer cell line MDA-MB-231 to unravel epigenetic changes induced by the drug. We identified differentially methylated sites (DMSs) enriched in promoter regions across the genome. Analysis of the CpG island promoter methylation identified 12 genes common to both drugs, and 50% of them are known to be methylated in patient samples that were hypomethylated by drugs belonging to the homeobox family transcription factors.Methylation analysis of the gene body revealed 910 and 952 genes to be hypermethylatedin ST08 and ST09 treated MDA-MB-231 cells respectively. Correlation of the gene body hypermethylation with expression revealed CACNAH1 to be upregulated in ST08 treatment and CDH23 upregulation in ST09.Further, integrated analysis of the WGBS with RNA-seq identified uniquely altered pathways - ST08 altered ECM pathway, and ST09 cell cycle, indicating drug-specific signatures.

Transcriptomics indicate nuclear division and cell adhesion not recapitulated in MCF7 and MCF10A compared to luminal A breast tumours

Breast cancer (BC) cell lines are useful experimental models to understand cancer biology. Yet, their relevance to modelling cancer remains unclear. To better understand the tumour-modelling efficacy of cell lines, we performed RNA-seq analyses on a combined dataset of 2D and 3D cultures of tumourigenic MCF7 and non-tumourigenic MCF10A. To our knowledge, this was the first RNA-seq dataset comprising of 2D and 3D cultures of MCF7 and MCF10A within the same experiment, which facilitates the elucidation of differences between MCF7 and MCF10A across culture types. We compared the genes and gene sets distinguishing MCF7 from MCF10A against separate RNA-seq analyses of clinical luminal A (LumA) and normal samples from the TCGA-BRCA dataset. Among the 1031 cancer-related genes distinguishing LumA from normal samples, only 5.1% and 15.7% of these genes also distinguished MCF7 from MCF10A in 2D and 3D cultures respectively, suggesting that different genes drive cancer-related differences in cell lines compared to clinical BC. Unlike LumA tumours which showed increased nuclear division-related gene expression compared to normal tissue, nuclear division-related gene expression in MCF7 was similar to MCF10A. Moreover, although LumA tumours had similar cell adhesion-related gene expression compared to normal tissues, MCF7 showed reduced cell adhesion-related gene expression compared to MCF10A. These findings suggest that MCF7 and MCF10A cell lines were limited in their ability to model cancer-related processes in clinical LumA tumours.

Bromodomain Protein BRD4-Mediated Mutant p53 Transcription Promotes TNBC Progression

TP53 is the most common mutated gene in human cancer. Mutant p53 protein loses its tumor-suppressor properties and gains oncogenic activity. Mutant p53 is a therapeutic target in a broad range of cancer types. However, how mutant p53 is epigenetically regulated during tumor progression remains elusive. In this study, we found that the upregulation of mutant p53 is mediated by bromodomain protein BRD4 in triple-negative breast cancer (TNBC) cells. Inhibition of BRD4 with its inhibitor JQ1 or knockdown of BRD4 suppressed the transcription of mutant p53, which led to the re-expression of p21, the inhibition of S-phase entry, and colony formation in TNBC cells. BRD4 also positively regulated the transcription of wild-type p53, whereas JQ1 treatment and knockdown of BRD4 decreased the expression of p21 in MCF-7 cells. Knockdown of BRD4 resulted in attenuation of TNBC tumor growth in vivo. Taken together, our results uncover a novel regulatory mechanism of mutant p53 via BRD4, and suggest that the bromodomain inhibitor suppresses tumorigenesis through targeting mutant p53 in TNBC.