Inhibiting epidermal growth factor receptor signalling potentiates mesenchymal–epithelial transition of breast cancer stem cells and their responsiveness to anticancer drugs

Purinergic signaling promotes premature senescence

Extracellular ATP activates P2 purinergic receptors. Whether purinergic signaling is functionally coupled to cellular senescence is largely unknown. We find that oxidative stress induced release of ATP and caused senescence in human lung fibroblasts. Inhibition of P2 receptors limited oxidative stress-induced senescence, while stimulation with exogenous ATP promoted premature senescence. Pharmacological inhibition of P2Y11 receptor (P2Y11R) inhibited premature senescence induced by either oxidative stress or ATP, while stimulation with a P2Y11R agonist was sufficient to induce cellular senescence. Our data show that both extracellular ATP and a P2Y11R agonist induced calcium (Ca++) release from the endoplasmic reticulum (ER) and that either inhibition of phospholipase C or intracellular Ca++ chelation impaired ATP-induced senescence. We also find that Ca++ that was released from the ER, following ATP-mediated activation of phospholipase C, entered mitochondria in a manner dependent on P2Y11R activation. Once in mitochondria, excessive Ca++ promoted the production of reactive oxygen species in a P2Y11R-dependent fashion, which drove development of premature senescence of lung fibroblasts. Finally, we show that conditioned medium derived from senescent lung fibroblasts, which were induced to senesce through the activation of ATP/P2Y11R-mediated signaling, promoted the proliferation of triple-negative breast cancer cells and their tumorigenic potential by secreting amphiregulin. Our study identifies the existence of a novel purinergic signaling pathway that links extracellular ATP to the development of a protumorigenic premature senescent phenotype in lung fibroblasts that is dependent on P2Y11R activation and ER-to-mitochondria calcium signaling.

Epidermal growth factor receptor inhibition potentiates chemotherapeutics-mediated sensitization of metastatic breast cancer stem cells

BACKGROUND

Metastasis has been a cause of the poor prognosis and cancer relapse of triple-negative breast cancer (TNBC) patients. The metastatic nature of TNBC is contributed by the breast cancer stem cells (CSCs) which have been implicated in tumorigenesis. Higher expression of epidermal growth factor receptor (EGFR) in breast CSCs has been used as a molecular target for breast cancer therapeutics. Thus, it necessitates the design and generation of efficacious EGFR inhibitors to target the downstream signaling associated with the cellular proliferation and tumorigenesis of breast cancer.

AIM

To generate efficacious EGFR inhibitors that can potentiate the chemotherapeutic-mediated mitigation of breast cancer tumorigenesis.

METHODS AND RESULTS

We identified small molecule EGFR inhibitors using molecular docking studies. In-vitro screening of the compounds was undertaken to identify the cytotoxicity profile of the small-molecule EGFR inhibitors followed by evaluation of the non-cytotoxic compounds in modulating the doxorubicin-induced migration, in-vitro tumorigenesis potential, and their effect on the pro-apoptotic genes' and protein markers' expression in TNBC cells. Compound 1e potentiated the doxorubicin-mediated inhibitory effect on proliferation, migration, in-vitro tumorigenesis capacity, and induction of apoptosis in MDA-MB-231 cells, and in the sorted CD24+-breast cancer cells and CD24-/CD44+-breast CSC populations. Orthotopic xenotransplantation of the breast CSCs-induced tumors in C57BL/6J mice was significantly inhibited by the low dose of Doxorubicin in the presence of compound 1e as depicted by molecular and immunohistochemical analysis.

CONCLUSION

Thus, the study suggests that EGFR inhibition-mediated sensitization of the aggressive and metastatic breast CSCs in TNBCs toward chemotherapeutics may reduce the relapse of the disease.

A New Benzo[6,7]oxepino[3,2-b] Pyridine Derivative Induces Apoptosis in Canine Mammary Cancer Cell Lines

CMC is the most frequently diagnosed cancer and one of the leading causes of death in non-spayed female dogs. Exploring novel therapeutic agents is necessary to increase the survival rate of dogs with CMC. MPOBA is a BZOP derivative that has a significant anticancer effect in a human cell line. The main goal of this study was to investigate the anticancer properties of MPOBA against two CMC cell lines (REM134 and CMGT071020) using a 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, a wound healing assay, a transwell migration assay, an Annexin V-FITC apoptosis assay with a flow cytometry analysis, a mRNA expression analysis using quantitative real-time PCR (qRT-PCR), and an immunohistochemistry (IHC). According to the accumulated studies, MPOBA caused significant concentration- and time-dependent reductions in cell proliferation and cell migration and induced apoptosis in both CMC cell lines. In gene expression analysis, nine canine genes, including TP53, BCL-2, BAX, epidermal growth factor receptor (EGFR), snail transcription factor (SNAIL), snail-related zinc-finger transcription factor (SLUG), TWIST, E-cadherin, and N-cadherin, were investigated. The mRNA expression results revealed that MPOBA induced upregulation of TP53 and overexpression of the pro-apoptotic gene BAX, together with an inhibition of BCL-2. Moreover, MPOBA also suppressed the mRNA expression levels of SNAIL, EGFR, and N-cadherin and induced upregulation of E-cadherin, crucial genes related to the epithelial-to-mesenchymal transition (EMT). However, there was no significant difference in the IHC results of the expression patterns of vimentin (VT) and cytokeratin (CK) between MPOBA-treated and control CMC cells. In conclusion, the results of the present study suggested that MPOBA exhibited significant anticancer activity by inducing apoptosis in both CMCs via upregulation of TP53 and BAX and downregulation of BCL-2 relative mRNA expression. MPOBA may prove to be a potential candidate drug to be further investigated as a therapeutic agent for CMC.

A comprehensive review on anticancer evaluation techniques

The development of effective anticancer strategies and the improvement of our understanding of cancer need analytical tools. Utilizing a variety of analytical approaches while investigating anti-cancer medicines gives us a thorough understanding of the traits and mechanisms concerned to cancer cells, which enables us to develop potent treatments to combat them. The importance of anticancer research may be attributed to various analytical techniques that contributes to the identification of therapeutic targets and the assessment of medication efficacy, which are crucial things in expanding our understanding of cancer biology. The study looks at methods that are often used in cancer research, including cell viability assays, clonogenic assay, flow cytometry, 2D electrophoresis, microarray, immunofluorescence, western blot caspase activation assay, bioinformatics, etc. The fundamentals, applications, and how each technique analytical advances our understanding of cancer are briefly reviewed.

Phenotyping EMT and MET cellular states in lung cancer patient liquid biopsies at a personalized level using mass cytometry

Malignant pleural effusions (MPEs) can be utilized as liquid biopsy for phenotyping malignant cells and for precision immunotherapy, yet MPEs are inadequately studied at the single-cell proteomic level. Here we leverage mass cytometry to interrogate immune and epithelial cellular profiles of primary tumors and pleural effusions (PEs) from early and late-stage non-small cell lung cancer (NSCLC) patients, with the goal of assessing epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) states in patient specimens. By using the EMT-MET reference map PHENOSTAMP, we observe a variety of EMT states in cytokeratin positive (CK+) cells, and report for the first time MET-enriched CK+ cells in MPEs. We show that these states may be relevant to disease stage and therapy response. Furthermore, we found that the fraction of CD33+ myeloid cells in PEs was positively correlated to the fraction of CK+ cells. Longitudinal analysis of MPEs drawn 2 months apart from a patient undergoing therapy, revealed that CK+ cells acquired heterogeneous EMT features during treatment. We present this work as a feasibility study that justifies deeper characterization of EMT and MET states in malignant cells found in PEs as a promising clinical platform to better evaluate disease progression and treatment response at a personalized level.

Mimicking 3D breast tumor-stromal interactions to screen novel cancer therapeutics

Most of the 3D breast tumor models used in drug screening studies only comprise tumor cells, keeping out other essential cell players of the tumor microenvironment. Tumor-associated macrophages and fibroblasts are frequently correlated with tumor progression and therapy resistance, and targeting these cells at the tumor site has been appointed as a promising therapeutic strategy. However, the translation of new therapies to the clinic has been hampered by the absence of cellular models that more closely mimic the features of in vivo breast tumor microenvironment. Therefore, the development of innovative 3D models able to provide consistent and predictive responses about the in vivo efficacy of novel therapeutics is still an unmet preclinical need. Herein, we have established an in vitro 3D heterotypic spheroid model including MCF-7 breast tumor cells, human mammary fibroblasts and human macrophages. To establish this model, different cell densities have been combined and characterized through the evaluation of the spheroid size and metabolic activity, as well as histological and immunohistochemistry analysis of the 3D multicellular structures. The final optimized 3D model consisted in a multicellular spheroid seeded at the initial density of 5000 cells and cell ratio of 1:2:1 (MCF-7:monocytes:fibroblasts). Our model recapitulates several features of the breast tumor microenvironment, including the formation of a necrotic core, spatial organization, and extracellular matrix production. Further, it was validated as a platform for drug screening studies, using paclitaxel, a currently approved drug for breast cancer treatment, and Gefitinib, a chemotherapeutic approved for lung cancer and in preclinical evaluation for breast cancer. Generally, the impact on the cell viability of the 3D model was less evident than in 2D model, reinforcing the relevance of such complex 3D models in addressing novel treatment approaches. Overall, the use of a 3D heterotypic spheroid of breast cancer could be a valuable tool to predict the therapeutic effect of new treatments for breast cancer patients, by recapitulating key features of the breast cancer microenvironment.

ZEB1 potentiates chemoresistance in breast cancer stem cells by evading apoptosis

Chemoresistance renders a challenge to the clinics to treat breast cancer patients. Current treatment strategies are effective in mitigating tumor growth but remain largely ineffective against cancer-initiating cells or breast Cancer Stem Cells (CSCs). Epithelial-to-mesenchymal-transition (EMT) regulates breast CSC physiology. Zinc finger E-box binding homeobox 1 (ZEB1) is a key EMT-transcription factor that regulates breast CSC - differentiation and metastasis. However, its potential role in modulating tumor chemoresistance has not yet been fully understood. In-silico analysis revealed a higher ZEB1 expression in breast cancer patients that leads to decreased overall and relapse-free survival. We generated sorted breast CSC with stable ZEB1 overexpression (CD24-/CD44+GFP-ZEB1) and/or silencing (CD24-/CD44+ZEB1 shRNA) as well as breast cancer cells with stable ZEB1 overexpression (CD24+GFP-ZEB1) and/or silencing (CD24+ZEB1 shRNA). An increased colony-forming efficiency and doxorubicin accumulation correlated with decreased promoter activity and expression profile of ABCC1 drug-efflux ABC transporter in CD24-/CD44+GFP-ZEB1. Additionally, CD24-/CD44+GFP-ZEB1 demonstrated doxorubicin-induced higher anti-apoptotic and lower pro-apoptotic protein expressions in the mitochondrial and cytosolic fractions. Chemoresistant CD24-/CD44+GFP-ZEB1 cells depicted 1000-fold higher IC-50 values of doxorubicin and decreased activation of JNK-p38 stress kinase molecular signaling-dependent mammosphere forming efficiency to evade apoptosis. Thus, ZEB1 and its downstream effectors are plausible therapeutic targets for the mitigation of breast cancer chemoresistance in patients.

Surface functionalization of extracellular vesicle nanoparticles with antibodies: a first study on the protein corona "variable"

To be profitably exploited in medicine, nanosized systems must be endowed with biocompatibility, targeting capability, the ability to evade the immune system, and resistance to clearance. Currently, biogenic nanoparticles, such as extracellular vesicles (EVs), are intensively investigated as the platform that naturally recapitulates these highly needed characteristics. EV native targeting properties and pharmacokinetics can be further augmented by decorating the EV surface with specific target ligands as antibodies. However, to date, studies dealing with the functionalization of the EV surface with proteins have never considered the protein corona "variable", namely the fact that extrinsic proteins may spontaneously adsorb on the EV surface, contributing to determine the surface, and in turn the biological identity of the EV. In this work, we explore and compare the two edge cases of EVs modified with the antibody Cetuximab (CTX) by chemisorption of CTX (through covalent binding via biorthogonal click-chemistry) and by formation of a physisorbed CTX corona. The results indicate that (i) no differences exist between the two formulations in terms of binding affinity imparted by molecular recognition of CTX versus its natural binding partner (epidermal growth factor receptor, EGFR), but (ii) significant differences emerge at the cellular level, where CTX-EVs prepared by click chemistry display superior binding and uptake toward target cells, very likely due to the higher robustness of the CTX anchorage.

Therapy-resistant breast cancer in focus: Clinically relevant mitigation by flavonoids targeting cancer stem cells

Significant limitations of the reactive medical approach in breast cancer management are clearly reflected by alarming statistics recorded worldwide. According to the WHO updates, breast malignancies become the leading cancer type. Further, the portion of premenopausal breast cancer cases is permanently increasing and demonstrates particularly aggressive patterns and poor outcomes exemplified by young patients with triple-negative breast cancer that lacks targeted therapy. Accumulating studies suggest the crucial role of stem cells in tumour biology, high metastatic activity, and therapy resistance of aggressive breast cancer. Therefore, targeting breast cancer stem cells is a promising treatment approach in secondary and tertiary breast cancer care. To this end, naturally occurring substances demonstrate high potential to target cancer stem cells which, however, require in-depth analysis to identify effective anti-cancer agents for cost-effective breast cancer management. The current article highlights the properties of flavonoids particularly relevant for targeting breast cancer stem cells to mitigate therapy resistance. The proposed approach is conformed with the principles of 3P medicine by applying predictive diagnostics, patient stratification and treatments tailored to the individualised patient profile. Expected impacts are very high, namely, to overcome limitations of reactive medical services improving individual outcomes and the healthcare economy in breast cancer management. Relevant clinical applications are exemplified in the paper.

Cell density modulates chemoresistance in breast cancer cells through differential expression of ABC transporters

BACKGROUND

Breast cancer patients undergoing chemotherapy encounter a significant challenge of chemoresistance because of drug efflux by ATP-binding cassette (ABC) transporters. Breast cancer cell density alters considerably throughout the early stages of primary and secondary tumor development. Although cell density in culture influences kinetics, the effects of varying cell densities on the chemoresistance of breast cancer cells remains largely unexplored.

METHODS AND RESULTS

We observed chemotherapeutics-induced differential gene and protein expression of ABC transporters in luminal and basal breast cancer cells cultured at low and high seeding densities. Low-density cultures depicted a significant increase in the mRNA expression of ABC transporters-ABCG2, ABCG1, ABCC4, ABCA2, ABCA3, ABCC2, ABCC3, ABCC6, ABCC7, and ABCC9 as compared with high-density cultures. Next, cells at both low and high seeding densities when pre-treated with cyclosporine A (CsA), a pan-inhibitor of ABC transporters, resulted in increased sensitization to chemotherapeutics-doxorubicin and tamoxifen at markedly low IC50 concentrations suggesting the role of ABC transporters. Finally, markedly high doxorubicin-drug accumulation, significantly increased expression of N-cadherin, and a significant decrease in chemotherapeutics-induced in vitro tumorigenesis was observed in low-density seeded breast cancer cells when pre-treated with CsA suggesting ABC transporters inhibition-mediated increased efficacy of chemotherapeutics.

CONCLUSION

These findings suggest that breast cancer cells grown at low seeding density imparts chemoresistance towards doxorubicin or tamoxifen by a differential increase in the expression of ABC transporters. Thus, a combinatorial treatment strategy including ABC transporter inhibitors and chemotherapeutics can be a way forward for overcoming the breast cancer chemoresistance.

Can EGFR be a therapeutic target in breast cancer?

Epidermal growth factor receptor (EGFR) is highly expressed in certain cancer types and is involved in regulating the biological characteristics of cancer progression, including proliferation, metastasis, and drug resistance. Various medicines targeting EGFR have been developed and approved for several cancer types, such as lung and colon cancer. To date, however, EGFR inhibitors have not achieved satisfactory clinical results in breast cancer, which continues to be the most serious malignant tumor type in females. Therefore, clarifying the underlying mechanisms related to the ineffectiveness of EGFR inhibitors in breast cancer and developing new EGFR-targeted strategies (e.g., combination therapy) remain critical challenges. Various studies have demonstrated aberrant expression and maintenance of EGFR levels in breast cancer. In this review, we summarize the regulatory mechanisms underlying EGFR protein expression in breast cancer cells, including EGFR mutations, amplification, endocytic dysfunction, recycling acceleration, and degradation disorders. We also discuss potential therapeutic strategies that act directly or indirectly on EGFR, including reducing EGFR protein expression, treating the target protein to mediate precise clearance, and inhibiting non-EGFR signaling pathways. This review should provide new therapeutic perspectives for breast cancer patients with high EGFR expression.

A Tumor Accelerator Based on Multicomponent Bone Scaffolds and Cancer Cell Homing

Bone tissue attracts cancer cell homing biologically, mechanically, or chemically. It is difficult and time consuming to identify their complex cross-talk using existed methods. In this study, a multi-component bone matrix was fabricated using gelatin, hydroxyapatite (HAp), and epidermal growth factor (EGF) as raw materials to investigate how “acellular” bone matrix affects cancer cell homing in bone. Then, EGF-responsive cancer cells were cultured with the scaffold in a dynamical bioreactor. For different culture periods, the effects of HAp, gelatin, and EGF on the cell adhesion, proliferation, 3D growth, and migration of cancer were evaluated. The results indicated that a small amount of calcium ion released from the scaffolds accelerated cancer MDA-MB-231 adhesion on the surface of inner pores. Moreover, degradable gelatin key caused cancer cell growth on the scaffold surface to turn into a 3D aggregation. Despite this, the formation of cancer spheroids was slow, and required 14 days of dynamic culture. Thankfully, EGF promoted cancer cell adhesion, proliferation, and migration, and cancer spheroids were observed only after 3-day culture. We concluded that the combination of the multiple components in this scaffold allows cancer cells to meet multiple requirements of cancer dynamic progression.

Breast Cancer Stem Cells: Signaling Pathways, Cellular Interactions, and Therapeutic Implications

Breast cancer stem cells (BCSCs) constitute a small population of cells within breast cancer and are characterized by their ability to self-renew, differentiate, and recapitulate the heterogeneity of the tumor. Clinically, BCSCs have been correlated with cancer progression, metastasis, relapse, and drug resistance. The tumorigenic roles of BCSCs have been extensively reviewed and will not be the major focus of the current review. Here, we aim to highlight how the crucial intrinsic signaling pathways regulate the fate of BCSCs, including the Wnt, Notch, Hedgehog, and NF-κB signaling pathways, as well as how different cell populations crosstalk with BCSCs within the TME, including adipocytes, endothelial cells, fibroblasts, and immune cells. Based on the molecular and cellular activities of BCSCs, we will also summarize the targeting strategies for BCSCs and related clinical trials. This review will highlight that BCSC development in breast cancer is impacted by both BCSC endogenous signaling and external factors in the TME, which provides an insight into how to establish a comprehensively therapeutic strategy to target BCSCs for breast cancer treatments.

Integrated regulation of chondrogenic differentiation in mesenchymal stem cells and differentiation of cancer cells

Chondrogenesis is the formation of chondrocytes and cartilage tissues and starts with mesenchymal stem cell (MSC) recruitment and migration, condensation of progenitors, chondrocyte differentiation, and maturation. The chondrogenic differentiation of MSCs depends on co-regulation of many exogenous and endogenous factors including specific microenvironmental signals, non-coding RNAs, physical factors existed in culture condition, etc. Cancer stem cells (CSCs) exhibit self-renewal capacity, pluripotency and cellular plasticity, which have the potential to differentiate into post-mitotic and benign cells. Accumulating evidence has shown that CSCs can be induced to differentiate into various benign cells including adipocytes, fibrocytes, osteoblast, and so on. Retinoic acid has been widely used in the treatment of acute promyelocytic leukemia. Previous study confirmed that polyploid giant cancer cells, a type of cancer stem-like cells, could differentiate into adipocytes, osteocytes, and chondrocytes. In this review, we will summarize signaling pathways and cytokines in chondrogenic differentiation of MSCs. Understanding the molecular mechanism of chondrogenic differentiation of CSCs and cancer cells may provide new strategies for cancer treatment.

Anti-cancer potentials of Gynura procumbens leaves extract against two canine mammary cancer cell lines

BACKGROUND

The anti-cancer effects of Gynura procumbens leaves extract (GPE) have been reported in various human cancers. However, the anti-cancer effects and molecular mechanisms of this extract on canine mammary cancer (CMC) have not yet been elucidated.

OBJECTIVES

The main goal of this study was to investigate the anti-cancer properties of GPE against two CMC cell lines (CHMp-13a and CHMp-5b).

METHODS

The GP leaves were extracted with 80% ethanol. Anti-cancer potentials of GPE on CHMp-13a and CHMp-5b cancer cell lines using dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide (MTT), wound healing, transwell migration, and caspase 3/7 activity assays were evaluated. The mRNA expression levels of two oncogenes: epidermal growth factor receptor (EGFR) and twist family bHLH transcription factor 1 (TWIST) and one tumour suppressor gene: phosphatase and tensin homolog (PTEN) in these cell lines were determined by quantitative real-time PCR (qRT-PCR). In addition, The EGFR and PTEN protein levels as well as protein kinase B (AKT) and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation levels expression were also evaluated by western blot analysis.

RESULTS

The results showed that GPE caused a significant concentration- and time-dependent reduction in cell proliferation of both CHMp-13a and CHMp-5b cells, detected by MTT assays. This extract also significantly suppressed cancer cell migration in both cell lines, tested by wound healing and transwell migration assays. Additionally, the increase in caspase 3/7 activity observed in both CMC cell treated with GPE suggests that GPE induced caspase 3/7 dependent apoptosis. Moreover, GPE significantly decreased EGFR mRNA and protein expression levels compared to control in both cell lines in a dose-dependent manner.

CONCLUSION

These findings emphasized that GPE has an in vitro anti-cancer activity against CMC by inhibiting EGFR signalling pathway. Thus, GPE may serve as an alternative therapy in CMC with high EGFR expression.

EGFR is a pivotal player of the E2/ERβ - mediated functional properties, aggressiveness, and stemness in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is defined by aggressive behavior, limited response to chemotherapy and lower overall survival rates. The increased metastatic potential of TNBC is a combined result of extensive extracellular matrix (ECM) remodeling that leads to cytoskeleton rearrangement and activation of epithelial-to-mesenchymal transition (EMT). The overexpression of epidermal growth factor receptor (EGFR) in TNBC tumors has been linked to induced expression of EMT-related molecules. EMT activation has often been associated with increased metastasis and stemness. Recently, we described the crucial role of EGFR/estrogen receptor beta (ERβ) interplay in the regulation of invasion and cell-matrix interactions. In this study, we report on the EGFR-ERβ functional relationship in connection to the aggressiveness and cancer stem cell (CSC)-like characteristics of TNBC cells. ERβ-suppressed and MDA-MB-231 cells were subjected to downstream EGFR inhibition and/or estradiol stimulation to assess alterations in functional parameters as well as in morphological characteristics, studied by scanning electron, atomic force, and immunofluorescence microscopies. Moreover, the expression and localization of key EMT and CSC-related markers were also evaluated by real-time qPCR, immunofluorescence microscopy, and flow cytometry. EGFR inhibition resulted in an overall suppression of aggressive functional characteristics, which occurred in an ERβ-mediated manner. These changes could be attributed to a reduction, at the molecular level, of EMT and stemness-linked markers, most notably reduced expression of Notch signaling constituents and the cell surface proteoglycan, syndecan-1. Collectively, our study highlights the importance of EGFR signaling as a key effector of aggressiveness, EMT, and stemness in an ERβ-dependent way in TNBC.

SNAI1-mediated transcriptional regulation of epithelial-to-mesenchymal transition genes in breast cancer stem cells

BACKGROUND

Triple-negative breast cancer (TNBC) tumors are composed of a heterogeneous population containing both cancer cells and cancer stem cells (CSCs). These CSCs are generated through an epithelial-to-mesenchymal transition (EMT), thus making it pertinent to identify the unique EMT-molecular targets that regulate this phenomenon.

METHODS AND RESULTS

In the present study, we performed in silico analysis of microarray data from luminal, Her2⁺, and TNBC cell lines and identified 15 relatively unexplored EMT-related differentially expressed genes (DEGs) along with the markedly high expression of EMT-transcription factor (EMT-TF), SNAI1. Interestingly, stable overexpression of SNAI1 in MCF-7 induced the expression of DEGs along with increased migration, invasion, and in vitro tumorigenesis that was comparable to TNBCs. Next, stable SNAI1 overexpression led to increased expression of DEGs that was reverted with SNAI1 silencing in both breast cancer cells and CSCs sorted from various TNBC cell lines. Higher fold enrichment of SNAI1 on E-boxes in the promoter regions suggested a positive regulation of ALCAM, MMP2, MMP13, MMP14, VCAN, ANKRD1, KRT16, CTGF, TGFRIIβ, PROCR negative regulation of CDH1, DSP and DSC3B by SNAI1 leading to EMT. Furthermore, SNAI1-mediated increased migration, invasion, and tumorigenesis in these sorted cells led to the activation of signaling mediators, ERK1/2, STAT3, Src, and FAK. Finally, the SNAI1-mediated activation of breast CSC phenotypes was perturbed by inhibition of downstream target, MMPs using Ilomastat.

CONCLUSION

Thus, the molecular investigation for the gene regulatory framework in the present study identified MMPs, a downstream effector in the SNAI1-mediated EMT regulation.

Activation of CD44-Lipoprotein lipase axis in breast cancer stem cells promotes tumorigenesis

Breast cancer stem cells (CSCs) are distinct CD44⁺-subpopulations that are involved in metastasis and chemoresistance. However, the underlying molecular mechanism of CD44 in breast CSCs-mediated tumorigenesis remains elusive. We observed high CD44 expression in advanced-stage clinical breast tumor samples. CD44 activation in breast CSCs sorted from various triple negative breast cancer (TNBC) cell lines induced proliferation, migration, invasion, mammosphere formation that were reversed in presence of inhibitor, 4-methyl umbelliferone or CD44 silencing. CD44 activation in breast CSCs induced Src, Akt, and nuclear translocation of pSTAT3. PCR arrays revealed differential expression of a metabolic gene, Lipoprotein lipase (LPL), and transcription factor, SNAI3. Differential transcriptional regulation of LPL by pSTAT3 and SNAI3 was confirmed by promoter-reporter and chromatin immunoprecipitation analysis. Orthotopic xenograft murine breast tumor model revealed high tumorigenicity of CD24^-/CD44⁺-breast CSCs as compared with CD24⁺-breast cancer cells. Furthermore, stable breast CSCs-CD44 shRNA and/or intratumoral administration of Tetrahydrolipstatin (LPL inhibitor) abrogated tumor progression and neoangiogenesis. Thus, LPL serves as a potential target for an efficacious therapeutics against aggressive breast cancer.

Utilizing the Hippo pathway as a therapeutic target for combating endocrine-resistant breast cancer

Drug resistance is always a great obstacle in any endocrine therapy of breast cancer. Although the combination of endocrine therapy and targeted therapy has been shown to significantly improve prognosis, refractory endocrine resistance is still common. Dysregulation of the Hippo pathway is often related to the occurrence and the development of many tumors. Targeted therapies of this pathway have played important roles in the study of triple negative breast cancer (TNBC). Targeting the Hippo pathway in combination with chemotherapy or other targeted therapies has been shown to significantly improve specific antitumor effects and reduce cancer antidrug resistance. Further exploration has shown that the Hippo pathway is closely related to endocrine resistance, and it plays a "co-correlation point" role in numerous pathways involving endocrine resistance, including related pathways in breast cancer stem cells (BCSCs). Agents and miRNAs targeting the components of the Hippo pathway are expected to significantly enhance the sensitivity of breast cancer cells to endocrine therapy. This review initially explains the possible mechanism of the Hippo pathway in combating endocrine resistance, and it concludes by recommending endocrine therapy in combination with therapies targeting the Hippo pathway in the study of endocrine-resistant breast cancers.

Mushrooms are potential foods against cancer: identified by molecular docking and molecular dynamics simulation

Epidermal Growth Factor Receptor (EGFR) is a promising drug target for the discovery of cancer chemotherapeutics. EGFR tyrosine kinase inhibitors become resistant due to mutation after a certain period of clinical application. The objective of the present study is to identify edible mushrooms as EGFR inhibitors. Structure-based VS of mushroom compounds using Autodock Vina in PyRx, re-docking of top scored hits using Autodock 4.2 were performed. Molecular dynamics (MD) was carried out with top hits to investigate the dynamic nature of the active site followed by MMPBSA binding energy calculation and ADME study. Analysis of MD results revealed the stability of Ag_76, Ag_77, Ag_88 and Ag_340 in the active site of EGFR as potential binders. Comparison of docking and MD results with known inhibitors also claimed the effectiveness of these hits. The sources of these potential hits are Polyozellus multiplex, Sarcodon imbricatus, and Cortinarius purpurascens, which may be effective as anti-cancer food after in vitro studies.

Emerging cellular and molecular mechanisms underlying anticancer indications of chrysin

Chrysin has been shown to exert several beneficial pharmacological activities. Chrysin has anti-cancer, anti-viral, anti-diabetic, neuroprotective, cardioprotective, hepatoprotective, and renoprotective as well as gastrointestinal, respiratory, reproductive, ocular, and skin protective effects through modulating signaling pathway involved in apoptosis, oxidative stress, and inflammation. In the current review, we discussed the emerging cellular and molecular mechanisms underlying therapeutic indications of chrysin in various cancers. Online databases comprising Scopus, PubMed, Embase, ProQuest, Science Direct, Web of Science, and the search engine Google Scholar were searched for available and eligible research articles. The search was conducted by using MeSH terms and keywords in title, abstract, and keywords. In conclusion, experimental studies indicated that chrysin could ameliorate cancers of the breast, gastrointestinal tract, liver and hepatocytes, bladder, male and female reproductive systems, choroid, respiratory tract, thyroid, skin, eye, brain, blood cells, leukemia, osteoblast, and lymph. However, more studies are needed to enhance the bioavailability of chrysin and evaluate this agent in clinical trial studies.

Evaluation of Benzamide-chalcone Derivatives as EGFR/CDK2 inhibitor: Synthesis, in-vitro Inhibition, and Molecular Modeling Studies

BACKGROUND

EGFR (Epidermal Growth Factor Receptor) and CDK2 (Cyclin Dependent Kinase 2) are important targets in the treatment of many solid tumors and different ligands of these receptors share many common structural features.

OBJECTIVE

The study involved synthesis of benzamide-substituted chalcones and determination of their antiproliferative activity as well as preliminary evaluation of EGFR and CDK2 inhibitory potential using both receptor binding and computational methods.

METHODS

We synthesized 13 benzamide-substituted chalcone derivatives and tested their antiproliferative activity against MCF-7, HT-29 and U373MG cell-lines using Sulforhodamine B Assay. Four compounds were examined for activity against EGFR and CDK2 kinase. The compounds were docked into both EGFR and CDK2 using Glide software. The stability of the interactions for most active compound was evaluated by Molecular Dynamics Simulation using Desmond software. Molecular Docking studies on mutant EGFR (T790M, T790M/L858R, and T790M/C797S) were also carried out.

RESULTS

From the SRB assay, we concluded that compounds 1g, and 1k were effective in inhibiting the growth of MCF-7 cell line whereas the other compounds were moderately active. Most compounds were either moderately active or inactive on U373 MG and HT-29 cell line. Compounds 1g and 1k showed good inhibitory activity against CDK2 kinase while 1d and 1f were moderately active. Compounds 1d, 1f, 1g, and 1k were moderately active against EGFR kinase. Molecular docking reveals involvement of one hydrogen bond with Met793 in binding with EGFR however; it was not stable during simulation and these compounds bind to the receptor mainly via hydrophobic contacts. This fact also points towards a different orientation of the inhibitor within the active site of EGFR kinase. Binding mode analysis for CDK2 inhibition studies indicate that hydrogen bonding interaction with Lys 33 and Leu83 are important for the activity. These interactions were found to be stable throughout the simulation. Considering the results for wild-type EGFR inhibition, the docking studies on mutants were performed and which indicate that the compounds bind to the mutant EGFR but the amino acid residues involved are similar to the wild-type EGFR and therefore, the selectivity seems to be limited.

CONCLUSION

These benzamide-substituted chalcone derivatives will be useful as lead molecules for the further development of newer inhibitors of EGFR and/or CDK2 kinases.

TWIST1-mediated transcriptional activation of PDGFRβ in breast cancer stem cells promotes tumorigenesis and metastasis

Triple-negative breast cancer (TNBC) patients often exhibit poor prognosis and breast cancer relapse due to metastasis. This results in secondary tumor generation at distant-unrelated organs that account for the majority of breast cancer-related deaths. Although breast cancer stem cells (CSCs) have been attributed to metastasis, a mechanistic understanding is essential for developing therapeutic interventions to combat breast cancer relapse. Breast CSCs are generated due to Epithelial-to-mesenchymal transition (EMT), regulated by transcription factors (EMT-TF) that are implicated in tumorigenesis and metastasis. However, the underlying mechanisms mediating these processes remain elusive. In the present study, we have reported that TWIST1, an EMT-TF, exhibits positive transcriptional regulation on PDGFRβ promoter, thus identifying PDGFRβ as one of the downstream targets of EMT regulation in breast CSCs. Breast cancer cells overexpressing PDGFRβ exhibited a significant increase in physiological and molecular properties comparable to that of breast CSCs, while molecular silencing of PDGFRβ in breast CSCs perturbed these phenomena. Mechanistically, PDGFRβ overexpression induced the activation of FAK and Src leading to cell migration and invasion. Orthotopic xenograft transplantation of stable breast cancer cells and CSCs with PDGFRβ overexpression in nude mice led to a significant increase in tumorigenesis, and metastasis to lung and liver as depicted by the significant increase in human gene-specific PDGFRβ and CD44 expression, and colocalization along with an expression of human-specific Alu sequences which were perturbed with stable silencing of PDGFRβ in breast CSCs. Thus, PDGFRβ plays a crucial role in inducing breast cancer tumorigenesis and metastasis that can be a plausible therapeutic target to treat TNBC patients.

Molecular mediators of breast cancer metastasis

Breast cancer has the highest incidence rate of malignancy in women worldwide. A major clinical challenge faced by patients with breast cancer treated by conventional therapies is frequent relapse. This relapse has been attributed to the cancer stem cell (CSC) population that resides within the tumor and possess stemness properties. Breast CSCs are generated when breast cancer cells undergo epithelial-mesenchymal transition resulting in aggressive, highly metastatic, and invasive phenotypes that exhibit resistance towards chemotherapeutics. Metastasis, a phenomenon that aids in the migration of breast CSCs, occurs through any of three different routes: hematogenous, lymphatic, and transcoelomic. Hematogenous dissemination of breast CSCs leads to metastasis towards distant unrelated organs like lungs, liver, bone, and brain causing secondary tumor generation. Activation of metastasis genes or silencing of metastasis suppressor genes often leads to the advancement of metastasis. This review focuses on various genes and molecular factors that have been implicated to regulate organ-specific breast cancer metastasis by defying the available therapeutic interventions.

Breast cancer stem cells: A review of their characteristics and the agents that affect them

The evolving concept that cancer stem cells (CSCs) are the driving element in cancer development, evolution and heterogeneity, has overridden the previous model of a tumor consisting of cells all with similar sequentially acquired mutations and a similar potential for renewal, invasion and metastasis. This paradigm shift has focused attention on therapeutically targeting CSCs directly as a means of eradicating the disease. In breast cancers, CSCs can be identified by cell surface markers and are characterized by their ability to self-renew and differentiate, resist chemotherapy and radiation, and initiate new tumors upon serial transplantation in xenografted mice. These functional properties of CSCs are regulated by both intracellular and extracellular factors including pluripotency-related transcription factors, intracellular signaling pathways and external stimuli. Several classes of natural products and synthesized compounds have been studied to target these regulatory elements and force CSCs to lose stemness and/or terminally differentiate and thereby achieve a therapeutic effect. However, realization of an effective treatment for breast cancers, focused on the biological effects of these agents on breast CSCs, their functions and signaling, has not yet been achieved. In this review, we delineate the intrinsic and extrinsic factors identified to date that control or promote stemness in breast CSCs and provide a comprehensive compilation of potential agents that have been studied to target breast CSCs, transcription factors and stemness-related signaling. Our aim is to stimulate further study of these agents that could become the basis for their use as stand-alone treatments or components of combination therapies effective against breast cancers.

In vitro and in silico antioxidant and antiproliferative activity of rhizospheric fungus Talaromyces purpureogenus isolate-ABRF2

The present study evaluated the potential biological activities of rhizospheric fungi isolated from the Achanakmar Biosphere Reserve, India. Fungus, Talaromyces purpureogenus isolate-ABRF2 from the soil of the Achanakmar biosphere was characterized by using morphological, biochemical and molecular techniques. Fungus was screened for the production of secondary metabolites using a specific medium. The metabolites were extracted using a suitable solvent and each fraction was subsequently evaluated for their antioxidant, antimicrobial, antiproliferative and anti-aging properties. The ethanolic extract depicted the highest antioxidant activity with 83%, 79%, 80% and 74% as assessed by ferric reducing power, 2,2-diphenyl 1-picrylhydrazyl, 2,2′-azino-bis3-ethylbenzthiazoline-6-sulfonic and phosphomolybdenum assays, respectively. Similarly, ethanolic extracts depicted marked antimicrobial activity as compared with standard antibiotics and antifungal agents as well as demonstrated significant antiproliferative property against a panel of mammalian cancer cell lines. Furthermore, different fractions of the purified ethanolic extract obtained using adsorption column chromatography were evaluated for antiproliferative property and identification of an active metabolite in the purified fraction using gas chromatography–mass spectroscopy and nuclear magnetic resonance techniques yielded 3-methyl-4-oxo-pentanoic acid. Thus, the present study suggests that the active metabolite 3-methyl-4-oxo-pentanoic acid extracted from Talaromyces purpureogenus isolate-ABRF2 has a potential antiproliferative, anti-aging, and antimicrobial therapeutic properties that will be further evaluated using in vivo studies in future.

Concise Synthesis of 1,1-Diarylvinyl Sulfones and Investigations on their Antiproliferative Activity <i>via</i> Tubulin Inhibition

BACKGROUND

Discovery of small molecules that inhibit tubulin polymerization is an attractive strategy for the development of new and improved anti-proliferative agents.

OBJECTIVE

A series of novel 2-sulfonyl-1,1-diarylethenes were designed towards this end keeping in view the favorable chemical and pharmacological virtues of unsaturated sulfones.

METHODS

Rapid, convenient and efficient two-step assembly of the designed molecules was achieved by the vicinal iodo-sulfonylation-Suzuki coupling sequence.

RESULTS

As hypothesized, these compounds showed good anti-proliferative activity against different tissuespecific cancer cell lines: MCF-7, DU-145, A-549, HepG2, and HeLa. The most active compound, pnitrophenyl ring-bearing analog, exhibited an IC50 value of 0.90μM against A-549 cells. Flow cytometry studies on this derivative revealed that it arrests the cell cycle of A-549 cells at the G2/M phase. This compound exhibited molecular binding to tubulin as well as tubulin polymerization inhibition comparable to that of colchicine.

CONCLUSION

A new class of potent, tubulin binding anticancer agents based on 1,1,-diarylvinyl sulfone scaffold has been designed and synthesized.

Cxcr6-Based Mesenchymal Stem Cell Gene Therapy Potentiates Skin Regeneration in Murine Diabetic Wounds

Mesenchymal stem cell (MSC) therapies for wound healing are often compromised due to low recruitment and engraftment of transplanted cells, as well as delayed differentiation into cell lineages for skin regeneration. An increased expression of chemokine ligand CXCL16 in wound bed and its cognate receptor, CXCR6, on murine bone-marrow-derived MSCs suggested a putative therapeutic relevance of exogenous MSC transplantation therapy. Induction of the CXCL16-CXCR6 axis led to activation of focal adhesion kinase (FAK), Src, and extracellular signal-regulated kinases 1/2 (ERK1/2)-mediated matrix metalloproteinases (MMP)-2 promoter regulation and expression, the migratory signaling pathways in MSC. CXCL16 induction also increased the transdifferentiation of MSCs into endothelial-like cells and keratinocytes. Intravenous transplantation of allogenic stable MSCs with Cxcr6 gene therapy potentiated skin tissue regeneration by increasing recruitment and engraftment as well as neovascularization and re-epithelialization at the wound site in excisional splinting wounds of type I and II diabetic mice. This study suggests that activation of the CXCL16-CXCR6 axis in bioengineered MSCs with Cxcr6 overexpression provides a promising therapeutic approach for the treatment of diabetic wounds.

In silico design, synthesis and activity of potential drug-like chrysin scaffold-derived selective EGFR inhibitors as anticancer agents

BACKGROUND & OBJECTIVE

Epidermal growth factor receptor (EGFR) signaling pathway is one of the promising and well-established targets for anticancer therapy. The objective of the present study was to identify new EGFR inhibitors using ligand and structure-based drug designing methods, followed by a synthesis of selected inhibitors and evaluation of their activity.

METHODS

A series of C-7-hydroxyproton substituted chrysin derivatives were virtually drawn to generate a small compound library that was screened using 3D QSAR model created from forty-two known EGFR tyrosine kinase inhibitors. Next, the obtained hits with fitness score ≥ 1.0 were subjected to molecular docking analysis. Based on the predicted activity and XP glide score, three EGFR inhibitors were synthesized and characterized using ¹H-NMR, ¹³C-NMR and MS. Finally, comparative in vitro investigation of the biological activity of synthesized inhibitors was performed with that of the parent molecule, chrysin.

RESULTS

The data depicted a 3.2-fold enhanced cytotoxicity of chrysin derivative, CHM-04 against breast cancer cells as compared with chrysin as well as its binding with EGFR protein. Furthermore, the biological activity of CHM-04 was comparable to the standard EGFR inhibitor, AG1478 in increasing apoptosis and decreasing the migratory potential of triple-negative breast cancer cells as well as significantly lowering the mammosphere forming ability of breast cancer stem cells.

CONCLUSION

The present study suggests CHM-04, an EGFR inhibitor possessing drug-like properties as a plausible therapeutic candidate against breast cancer.

Glutathione S-transferase omega 1 inhibition activates JNK-mediated apoptotic response in breast cancer stem cells

Glutathione S-transferase omega 1 (GSTO1) contributes to the inactivation of a wide range of drug compounds via conjugation to glutathione during phase reactions. Chemotherapy-induced GSTO1 expression in breast cancer cells leads to chemoresistance and promotes metastasis. In search of novel GSTO1 inhibitors, we identified S2E, a thia-Michael adduct of sulfonamide chalcone with low LC₅₀ (3.75 ± 0.73 μm) that binds to the active site of GSTO1, as revealed by molecular docking (glide score: -8.1), cellular thermal shift assay and fluorescence quenching assay (K_b  ≈ 10 × 10⁵  mol·L^-1 ). Docking studies confirmed molecular interactions between GSTO1 and S2E, and identified the hydrogen bond donor Val-72 (2.14 Å) and hydrogen bond acceptor Ser-86 (2.77 Å). Best pharmacophore hypotheses could effectively map S2E and identified the 4-methyl group of the benzene sulfonamide ring as crucial to its anti-cancer activity. Lack of a thiophenyl group in another analog, 2e, reduced its efficacy as observed by cytotoxicity and pharmacophore matching. Furthermore, GSTO1 inhibition by S2E, along with tamoxifen, led to a significant increase in apoptosis and decreased migration of aggressive MDA-MB-231 cells, as well as significantly decreased migration, invasion and mammosphere formation in sorted breast cancer stem cells (CSCs, CD24^- /CD44⁺ ). GSTO1 silencing in breast CSCs also significantly increased apoptosis and decreased migration. Mechanistically, GSTO1 inhibition activated the c-Jun N-terminal kinase stress kinase, inducing a mitochondrial apoptosis signaling pathway in breast CSCs via the pro-apoptotic proteins BAX, cytochrome c and cleaved caspase 3. Our study elucidated the role of the GSTO1 inhibitor S2E as a potential therapeutic strategy for preventing chemotherapy-induced breast CSC-mediated cancer metastasis and recurrence.

Cellular crosstalk mediated by platelet-derived growth factor BB and transforming growth factor β during hepatic injury activates hepatic stellate cells

Apoptotic hepatocytes release factors that activate hepatic stellate cells (HSCs), thereby inducing hepatic fibrosis. In the present study, in vivo and in vitro injury models were established using acetaminophen, ethanol, carbon tetrachloride, or thioacetamide. Histology of hepatotoxicant-induced diseased hepatic tissue correlated with differential expression of fibrosis-related genes. A marked increase in co-staining of transforming growth factor β receptor type II (TGFRIIβ) – desmin or α-smooth muscle actin – platelet-derived growth factor receptor β (PDGFRβ), markers of activated HSCs, in liver sections of these hepatotoxicant-treated mice also depicted an increase in Annexin V – cytokeratin expressing hepatocytes. To understand the molecular mechanisms of disease pathology, in vitro experiments were designed using the conditioned medium (CM) of hepatotoxicant-treated HepG2 cells supplemented to HSCs. A significant increase in HSC proliferation, migration, and expression of fibrosis-related genes and protein was observed, thereby suggesting the characteristics of an activated phenotype. Treating HepG2 cells with hepatotoxicants resulted in a significant increase in mRNA expression of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β (TGFβ). CM supplemented to HSCs resulted in increased phosphorylation of PDGFRβ and TGFRIIβ along with its downstream effectors, extracellular signal-related kinase 1/2 and focal adhesion kinase. Neutralizing antibodies against PDGF-BB and TGFβ effectively perturbed the hepatotoxicant-treated HepG2 cell CM-induced activation of HSCs. This study suggests PDGF-BB and TGFβ as potential molecular targets for developing anti-fibrotic therapeutics.

Breast cancer stem cells: Features, key drivers and treatment options

The current view is that breast cancer is a stem cell disease characterized by the existence of cancer cells with stem-like features and tumor-initiating potential. These cells are made responsible for tumor dissemination and metastasis. Common therapies by chemotherapeutic drugs fail to eradicate these cells and rather increase the pool of cancer stem cells in tumors, an effect that may increase the likelyhood of recurrence. Fifteen years after the first evidence for a small stem-like subpopulation playing a major role in breast cancer initiation has been published a large body of knowledge has been accumulated regarding the signaling cascades and proteins involved in maintaining stemness in breast cancer. Differences in the stem cell pool size and in mechanisms regulating stemness in the different breast cancer subtypes have emerged. Overall, this knowledge offers new approaches to intervene with breast cancer stem cell activity. New options are particularly needed for the treatment of triple-negative breast cancer subtype, which is particularly rich in cancer stem cells and is also the subtype for which specific therapies are still not available.

Total Synthesis of Desmethyl Jahanyne and Its Lipo-Tetrapeptide Conjugates Derived from Parent Skeleton as BCL-2-Mediated Apoptosis-Inducing Agents

The total synthesis of highly potent and scarcely available marine natural product (-)-jahanyne was attempted resulting in a solution-phase synthesis of pruned versions with comparable activity. A simple and facile synthetic route was employed for the preparation of pruned congeners and would be scalable. The lipophilic tail of the natural product was synthesized from R-(+)-citronellol, utilizing easily available chemicals. All the synthesized compounds were screened for apoptotic activity against a panel of cell lines. These compounds depicted marked binding to B cell lymphoma 2 till 50 °C in cellular thermal shift analysis.

Nicotine increases apoptosis in HUVECs cultured in high glucose/high fat via Akt ubiquitination and degradation

It is well-documented that nicotine, the main active ingredient in cigarettes, results in endothelial cell injury in numerous diseases. However, whether nicotine plays a crucial role in endothelial cell injury in diabetes and the exact molecular mechanism that mediates this process have not been fully elucidated. The current study aimed to investigate the effects of nicotine on endothelial cell injury in diabetes and the specific molecular mechanism by which it plays a role. Human umbilical vein endothelial cells (HUVECs) were incubated in HG/HF media and treated with nicotine, PYR-41 (a selective ubiquitin E1 inhibitor), Akt-overexpressing adenovirus, or TTC3 and MUL1 shRNA adenovirus. Cell viability was subsequently detected by the CCK8 assay, and apoptosis was examined by caspase-3 cleavage and activity analysis. Compared to the HG/HF incubated group, nicotine incubation significantly decreased cell survival and increased apoptosis. Moreover, nicotine induced Akt degradation via UPS, and Akt overexpression blocked nicotine-induced apoptosis in HUVECs cultured in HG/HF media. Furthermore, the TTC3 and MUL1 shRNA adenovirus dramatically decreased the Akt ubiquitination and apoptosis induced by nicotine. These results indicate that nicotine-induced Akt ubiquitination and degradation occurs through TTC3 and MUL1 and results in a dramatic increase in apoptosis in HUVECs cultured in HG/HF media.

Whey Protein Concentrate Renders MDA-MB-231 Cells Sensitive to Rapamycin by Altering Cellular Redox State and Activating GSK3β/mTOR Signaling

Whey protein concentrate (WPC) is an amino acid-rich supplement that has been shown to increase cellular antioxidant capacity. Mammalian target of rapamycin (mTOR) is a crucial regulator of signaling in mammalian cells, and serves as a therapeutic target for triple-negative breast cancer (TNBC). This study was designed to investigate the effect of combining WPC with rapamycin on MDA-MB-231 human breast cancer cells. These cells were found to be insensitive to rapamycin and exhibited higher glutathione (GSH) and reactive oxygen species levels than non-tumorigenic MCF-10A cells. However, for MDA-MB-231 cells, the half maximal inhibitory concentration of rapamycin was lower when this drug was administered in combination with WPC than when used alone. Furthermore, combining WPC with rapamycin depleted GSH levels and reduced Nrf2 nuclear accumulation. In addition, WPC activated GSK3β/mTOR signaling, and GSK3β appeared to be involved in the WPC-mediated Nrf2 reduction and mTOR activation. In conclusion, WPC induced rapamycin sensitivity in MDA-MB-231 cells by altering their redox state and activating GSK3β/mTOR signaling. These results not only suggest a novel therapeutic approach for breast cancer treatment, but also provide insight into the critical pathways affecting the resistance to mTOR inhibition observed in a subgroup of TNBC patients.

Synthesis, characterization and biological evaluation of formononetin derivatives as novel EGFR inhibitors via inhibiting growth, migration and inducing apoptosis in breast cancer cell line

Novel formononetin derivative 4v inhibited MDA-MB-231 cell proliferation, migration and induced apoptosis through targeting EGFR.