Drug-resistant Breast Cancer Research Articles

Activation of the Anaphase Promoting Complex Restores Impaired Mitotic Progression and Chemosensitivity in Multiple Drug-Resistant Human Breast Cancer.

The development of multiple-drug-resistant (MDR) cancer all too often signals the need for toxic alternative therapy or palliative care. Our recent in vivo and in vitro studies using canine MDR lymphoma cancer cells demonstrate that the Anaphase Promoting Complex (APC) is impaired in MDR cells compared to normal canine control and drug-sensitive cancer cells. Here, we sought to establish whether this phenomena is a generalizable mechanism independent of species, malignancy type, or chemotherapy regime. To test the association of blunted APC activity with MDR cancer behavior, we used matched parental and MDR MCF7 human breast cancer cells, and a patient-derived xenograft (PDX) model of human triple-negative breast cancer. We show that APC activating mechanisms, such as APC subunit 1 (APC1) phosphorylation and CDC27/CDC20 protein associations, are reduced in MCF7 MDR cells when compared to chemo-sensitive matched cell lines. Consistent with impaired APC function in MDR cells, APC substrate proteins failed to be effectively degraded. Similar to our previous observations in canine MDR lymphoma cells, chemical activation of the APC using Mad2 Inhibitor-1 (M2I-1) in MCF7 MDR cells enhanced APC substrate degradation and resensitized MDR cells in vitro to the cytotoxic effects of the alkylating chemotherapeutic agent, doxorubicin (DOX). Using cell cycle arrest/release experiments, we show that mitosis is delayed in MDR cells with elevated substrate levels. When pretreated with M2I-1, MDR cells progress through mitosis at a faster rate that coincides with reduced levels of APC substrates. In our PDX model, mice growing a clinically MDR human triple-negative breast cancer tumor show significantly reduced tumor growth when treated with M2I-1, with evidence of increased DNA damage and apoptosis. Thus, our results strongly support the hypothesis that APC impairment is a driver of aggressive tumor development and that targeting the APC for activation has the potential for meaningful clinical benefits in treating recurrent cases of MDR malignancy.

Anticancer Activity of Encapsulated Pearl Millet Polyphenol-Rich Extract against Proliferating and Non-Proliferating Breast Cancer Cells In Vitro.

Plant-derived polyphenols are bioactive compounds with potential health-promoting properties including antioxidant, anti-inflammatory, and anticancer activity. However, their beneficial effects and biomedical applications may be limited due to their low bioavailability. In the present study, we have considered a microencapsulation-based drug delivery system to investigate the anticancer effects of polyphenol-rich (apigenin, caffeic acid, and luteolin) fractions, extracted from a cereal crop pearl millet (Pennisetum glaucum), using three phenotypically different cellular models of breast cancer in vitro, namely triple negative HCC1806, ER-positive HCC1428, and HER2-positive AU565 cells. Encapsulated polyphenolic extract induced apoptotic cell death in breast cancer cells with different receptor status, whereas it was ineffective against non-tumorigenic MCF10F cells. Encapsulated polyphenolic extract was also found to be cytotoxic against drug-resistant doxorubicin-induced senescent breast cancer cells that were accompanied by increased levels of apoptotic and necrotic markers, cell cycle inhibitor p21 and proinflammatory cytokine IL8. Furthermore, diverse responses to the stimulation with encapsulated polyphenolic extract in senescent breast cancer cells were observed, as in the encapsulated polyphenolic extract-treated non-proliferating AU565 cells, the autophagic pathway, here cytotoxic autophagy, was also induced, as judged by elevated levels of beclin-1 and LC3b. We show for the first time the anti-breast cancer activity of encapsulated polyphenolic extract of pearl millet and postulate that microencapsulation may be a useful approach for potentiating the anticancer effects of phytochemicals with limited bioavailability.

SiRNA treatment targeting integrin α11 overexpressed via EZH2-driven axis inhibits drug-resistant breast cancer progression

BackgroundBreast cancer, the most prevalent cancer in women worldwide, faces treatment challenges due to drug resistance, posing a serious threat to patient survival. The present study aimed to identify the key molecules that drive drug resistance and aggressiveness in breast cancer cells and validate them as therapeutic targets.MethodsTranscriptome microarray and analysis using PANTHER pathway and StemChecker were performed to identify the most significantly expressed genes in tamoxifen-resistant and adriamycin-resistant MCF-7 breast cancer cells. Clinical relevance of the key genes was determined using Kaplan-Meier survival analyses on The Cancer Genome Atlas dataset of breast cancer patients. Gene overexpression/knockdown, spheroid formation, flow cytometric analysis, chromatin immunoprecipitation, immunocytochemistry, wound healing/transwell migration assays, and cancer stem cell transcription factor activation profiling array were used to elucidate the regulatory mechanism of integrin α11 expression. Tumour-bearing xenograft models were used to demonstrate integrin α11 is a potential therapeutic target.ResultsIntegrin α11 was consistently upregulated in drug-resistant breast cancer cells, and its silencing inhibited cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) while restoring sensitivity to anticancer drugs. HIF1α, GLI-1, and EZH2 contributed the most to the regulation of integrin α11 and EZH2 expression, with EZH2 being more necessary for EZH2 autoinduction than HIF1α and GLI-1. Additionally, unlike HIF1α or EZH2, GLI-1 was the sole transcription factor activated by integrin-linked focal adhesion kinase, indicating GLI-1 as a key driver of the EZH2-integrin α11 axis operating for cancer stem cell survival and EMT. Kaplan-Meier survival analysis using The Cancer Genome Atlas (TCGA) dataset also revealed both EZH2 and integrin α11 could be strong prognostic factors of relapse-free and overall survival in breast cancer patients. However, the superior efficacy of integrin α11 siRNA therapy over EZH2 siRNA treatment was demonstrated by enhanced inhibition of tumour growth and prolonged survival in murine models bearing tumours.ConclusionOur findings elucidate that integrin α11 is upregulated by EZH2, forming a positive feedback circuit involving FAK-GLI-1 and contributing to drug resistance, cancer stem cell survival and EMT. Taken together, the results suggest integrin α11 as a promising prognostic marker and a powerful therapeutic target for drug-resistant breast cancer.

Blockade of a novel MAP4K4-LATS2-SASH1-YAP1 cascade inhibits tumorigenesis and metastasis in luminal breast cancer

Novel components in the noncanonical Hippo pathway that mediate the growth, metastasis, and drug resistance of breast cancer (BC) cells need to be identified. Here, we showed that expression of SAM and SH3 domain-containing protein 1 (SASH1) is negatively correlated with expression of mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) in a subpopulation of patients with luminal-subtype BC. Downregulated SASH1 and upregulated MAP4K4 synergistically regulated the proliferation, migration, and invasion of luminal-subtype BC cells. The expression of LATS2, SASH1, and YAP1 and the phosphorylation of YAP1 were negatively regulated by MAP4K4, and LATS2 then phosphorylated SASH1 to form a novel MAP4K4-LATS2-SASH1-YAP1 cascade. Dephosphorylation of Yes1 associated transcriptional regulator (YAP1), YAP1/TAZ nuclear translocation, and downstream transcriptional regulation of YAP1 were promoted by the combined effects of ectopic MAP4K4 expression and SASH1 silencing. Targeted inhibition of MAP4K4 blocked proliferation, cell migration, and ER signaling both invitro and invivo. Our findings reveal a novel MAP4K4-LATS2-SASH1-YAP1 phosphorylation cascade, a noncanonical Hippo pathway that mediates ER signaling, tumorigenesis, and metastasis in breast cancer. Targeted intervention with this noncanonical Hippo pathway may constitute a novel alternative therapeutic approach for endocrine-resistant BC.

IL-7R Expression Correlates with Prognosis in Breast Cancer.

The tumor microenvironment (TME) exerts a significant influence on the development, invasion, metastasis, and drug resistance of breast cancer. Therefore, this study sought to investigate potential prognostic factors and markers indicative of TME remodeling in breast cancer, utilizing data from the TCGA database. In this study, transcriptome RNA-seq data from 1222 breast cancer samples were processed using CIBERSORT and ESTIMATE algorithms. We conducted a differential gene expression analysis utilizing COX regression analysis and constructed protein-protein interaction (PPI) networks for enhanced visualization. Through univariate COX analysis and cross-analysis within PPI networks, the Interleukin-7 receptor (IL-7R) emerged as a potential predictor. Subsequently, we performed a comprehensive investigation encompassing single-gene survival analysis, clinical correlation assessment, and GSEA enrichment analysis targeting IL-7R as a core gene associated with prognosis. We examined the expression of IL-7R in human breast cancer and normal breast tissue through clinical studies and cytology experiments, followed by an indepth analysis of the relationship between IL-7R and breast cancer. The survival analysis revealed that breast cancer patients with elevated IL-7R expression experienced prolonged survival compared to those with lower IL-7R levels. Results obtained from the Wilcoxon rank-sum test, along with clinical and cellular experiments, indicated higher IL-7R expression in tumor samples compared to normal samples. Correlation tests conducted between IL-7R expression and clinicopathological stage characteristics highlighted statistically significant associations between IL-7R expression and the T and M stages. Additionally, cell classification analysis of tumor-infiltrating immune cells (TIC) proportion showed that activated CD4+ T cells and CD8 T cells of memory B cells were positively correlated with IL-7R expression. These findings further underscored the impact of IL-7R levels on the tumor microenvironment (TME). IL-7R emerges as a potential prognostic indicator for breast cancer patients, particularly in sustaining the immunoactive status of the tumor microenvironment (TME) and contributing to immune reconstitution. These findings offer novel insights into breast cancer treatment strategies.

GALNT6, GALNT14, and Gal-3 in association with GDF-15 promotes drug resistance and stemness of breast cancer via β-catenin axis

N-acetylgalactosaminyltransferases (GALNTs) are a polypeptide responsible for aberrant glycosylation in breast cancer (BC), but the mechanism is unclear. In this study, expression levels of GALNT6, GALNT14, and Gal-3 were assessed in BC, and their association with GDF-15, β-catenin, stemness (SOX2 and OCT4), and drug resistance marker (ABCC5) was evaluated. Gene expression of GALNT6, GALNT14, Gal-3, GDF-15, OCT4, SOX2, ABCC5, and β-catenin in tumor and adjacent non-tumor tissues (n = 30) was determined. The same was compared with GEO-microarray datasets. A significant increase in the expression of candidate genes was observed in BC tumor compared to adjacent non-tumor tissue; and in pre-therapeutic patients compared to post-therapeutic. GALNT6, GALNT14, Gal-3, and GDF-15 showed positive association with β-catenin, SOX2, OCT4, and ABCC5 and were significantly associated with poor Overall Survival. Our findings were also validated via in silico analysis. Our study suggests that GALNT6, GALNT14, and Gal-3 in association with GDF-15 promote stemness and intrinsic drug resistance in BC, possibly by β-catenin signaling pathway.

Reversal of drug resistance in breast cancer cells by photodynamic action mediated by curcumin/Ko143/PLGA nanoparticles

Objective: The objective of this study is to prepare Cur/Ko143/PLGA that encapsulate the photosensitizer curcumin (Cur) and the multidrug transporter-specific inhibitor Ko143 to investigate its application in reversing drug resistance in breast cancer and evaluate its properties and therapeutic efficacy. Results: After successful preparation of nanoparticles, the encapsulation rate of Cur/Ko143/PLGA was 73.8% ± 1.8%, and the drug loading rate was 2.8% ± 0.1%. The Cur/Ko143/PLGA were spherical and regular in morphology under transmission electron microscopy. The nanoparticles were morphologically intact, were uniform in size, and did not show significant aggregation under scanning electron microscopy. The average particle size of Cur/Ko143/PLGA was 232.32 ± 10.60 nm, the polymer dispersion index was 0.01, and the zeta potential was −17.25 ± 0.65 mV, as determined by laser particle sizing. In vitro ultrasound observation showed that Cur/Ko143/PLGA were enhanced in both the B-mode and contrast modes. Intracellular Cur fluorescence detection, biocompatibility testing, cell scratch experiment, flow detection of apoptosis, live–dead staining, and actin polymerization test all prove that new nanomaterials have better photodynamic efficacy. Conclusion: Drug-carrying Cur/Ko143/PLGA nanoparticles can increase the concentration of the intracellular photosensitizer Cur and increase the photodynamic efficacy by inhibiting an efflux pump, which is expected to become a new therapeutic strategy.

Noninvasive Artificial Intelligence System for Early Predicting Residual Cancer Burden during Neoadjuvant Chemotherapy in Breast Cancer.

To develop an artificial intelligence (AI) system for the early prediction of residual cancer burden (RCB) scores during neoadjuvant chemotherapy (NAC) in breast cancer. RCB III indicates drug resistance in breast cancer, and early detection methods are lacking. This study enrolled 1048 patients with breast cancer from four institutions, who were all receiving NAC. Magnetic resonance images were collected at the pre- and mid-NAC stages, and radiomics and deep learning features were extracted. A multitask AI system was developed to classify patients into three groups (RCB 0-I, II, and III ) in the primary cohort (PC, n=335). Feature selection was conducted using the Mann-Whitney U- test, Spearman analysis, least absolute shrinkage and selection operator regression, and the Boruta algorithm. Single-modality models were developed followed by model integration. The AI system was validated in three external validation cohorts. (EVCs, n=713). Among the patients, 442 (42.18%) were RCB 0-I, 462 (44.08%) were RCB II and 144 (13.74%) were RCB III. Model-I achieved an area under the curve (AUC) of 0.975 in the PC and 0.923 in the EVCs for differentiating RCB III from RCB 0-II. Model-II distinguished RCB 0-I from RCB II-III, with an AUC of 0.976 in the PC and 0.910 in the EVCs. Subgroup analysis confirmed that the AI system was consistent across different clinical T stages and molecular subtypes. The multitask AI system offers a noninvasive tool for the early prediction of RCB scores in breast cancer, supporting clinical decision-making during NAC.

Abstract 4566: Synergistic anticancer activity of cannabinoids and beta caryophyllene in xenograft mouse model of triple negative breast cancer

Abstract Combination therapy, a treatment modality that studies the effect of two or more drugs is the most common strategy used to overcome drug resistance in cancer. Cannabinoids have been proven to be potential anticancer agents. Terpenes have also been demonstrated to exhibit anticancer activity. The purpose of this study was to evaluate the effect of combinations of various cannabinoids and terpenes against drug resistant lung and breast cancer. Several cannabinoids and terpenes such as cannabidiol (CBD), cannabichromene (CBC), cannabidiolic acid (CBDA), cannabidivarin (CBDV), cannabinol (CBN), cannabigerol (CBG) and β-caryophyllene (BC), bisabolol, myrcene, linalool, limonene, geraniol, neralidol, α-pinene, α-terpineol, γ-terpinene respectively were screened for their anticancer activity against MDA MB 231 DOX RT, H1975 OSM RT, PDX Lung cancer cell lines using 2D cytotoxicity and 3D spheroids assay. It was found that the cytotoxic potential of combinations of cannabinoids with BC increased by 10 folds in comparison to their individual anticancer activity. The combinations that exhibit synergistic action were determined from combination index (CI) values using compusyn software. Other assays such as colony formation, wound healing, apoptotic assay, cell cycle analysis by flow cytometry elucidated the possible mechanism underlying the synergism of the combinations investigated. CBC+BC was proven to be the most potent combination from all the in-vitro studies and hence was further evaluated in in-vivo tumor xenografts. Briefly, 5 million MDA MB 231 DOX RT cells were injected by S.C route in the right flank region of BALB/c nude mice. The animals were treated after the tumor volume reached 180-200mm3. The animals were administered CBC (15mg/kg, i.p.), BC (100mg/kg, i.p.) and CBC+BC thrice a week for two weeks. The tumor volume in the combination group was reduced by 2 folds relative to individual treatments and 4 folds relative to control. Western blot analysis of tumor xenografts showed downregulation of apoptotic markers such as PARP, mTOR, pAMPK, Survivin, autophagy markers such as LC 3, Glypican 5 and migration markers such as vimentin and Integrin. Immune check point proteins such as PD-L1 and PD-1 were also downregulated by combination treatment. This was further validated by qPCR. In conclusion, CBC induces programmed cell death in tumors and induces autophagy whereas BC inhibits migration and thus this combination was able to overcome resistance than individual therapies in a synergistic fashion. Citation Format: Mounika Aare, Islauddin Khan, Aakash Nathani, Breana Boirie, Arvind Bagde, Mandip Singh. Synergistic anticancer activity of cannabinoids and beta caryophyllene in xenograft mouse model of triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4566.

Abstract 4673: Genome-scale metabolic models identify gene targets that enhance drug response of drug-resistant breast cancer cells

Abstract Adaptive drug resistance poses a significant therapeutic challenge in treatment of breast cancer patients. Metabolic reprogramming in cancer cells is one of the major mechanisms associated with drug resistance. In this study, we aim to identify gene targets that enhance the drug response of drug-resistant breast cancer cells through downregulation. We hypothesized that metabolic perturbation in drug-resistant breast cancer cells could revert their metabolic features to those of drug-sensitive cells. To predict such gene targets, we used a computational model known as a genome-scale metabolic model (GEM). A GEM simulates the entire metabolic reaction fluxes of a cell under varying genetic and/or environmental conditions. We specifically targeted two engineered MCF7 breast cancer cell lines: one resistant to doxorubicin and the other to paclitaxel. First, we generated proteome data from drug-sensitive and drug-resistant MCF7 cell lines, and used them to construct the cell-specific GEMs. Subsequently, single-gene knockout simulation was conducted using these cell-specific GEMs. The initial list of the gene knockout targets was subjected to pathway analysis involving proteome and metabolome data to finalize the gene targets. The final gene targets were expected to lead to metabolic features similar to those of drug-sensitive MCF7 upon the downregulation. In vitro experiments using inhibitors were conducted to validate these predicted gene targets. This study provides a computational approach that can also be applied to other types of drug-resistant cancer cells. Citation Format: Hae Deok Jung, JinA Lim, Han Suk Ryu, Yoosik Kim, Hyun Uk Kim. Genome-scale metabolic models identify gene targets that enhance drug response of drug-resistant breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4673.

Targeted dual degradation of HER2 and EGFR obliterates oncogenic signaling, overcomes therapy resistance, and inhibits metastatic lesions in HER2-positive breast cancer models

AimsHuman epidermal growth factor receptor 2 (HER2) is an oncogenic receptor tyrosine kinase amplified in approximately 20% of breast cancer (BC). HER2-targeted therapies are the linchpin of treating HER2-positive BC. However, drug resistance is common, and the main resistance mechanism is unknown. We tested the hypothesis that drug resistance results mainly from inadequate or lack of inhibition of HER2 and its family member epidermal growth factor receptor (EGFR). MethodsWe used clinically relevant cell and tumor models to assess the impact of targeted degradation of HER2 and EGFR on trastuzumab resistance. Trastuzumab is the most common clinically used HER2 inhibitor. Targeted degradation of HER2 and EGFR was achieved using recombinant human protein PEPDG278D, which binds to the extracellular domains of the receptors. siRNA knockdown was used to assess the relative importance of EGFR and HER2 in trastuzumab resistance. ResultsBoth HER2 and EGFR are overexpressed in all trastuzumab-resistant HER2-positive BC cell and tumor models and that all trastuzumab-resistant models are highly vulnerable to targeted degradation of HER2 and EGFR. Degradation of HER2 and EGFR induced by PEPDG278D causes extensive inhibition of oncogenic signaling in trastuzumab-resistant HER2-positive BC cells. This is accompanied by strong growth inhibition of cultured cells, orthotopic patient-derived xenografts, and metastatic lesions in the brain and lung of trastuzumab-resistant HER2-positive BC. siRNA knockdown indicates that eliminating both HER2 and EGFR is necessary to maximize therapeutic outcome. ConclusionsThis study unravels the therapeutic vulnerability of trastuzumab-resistant HER2-positive BC and shows that an agent that targets the degradation of both HER2 and EGFR is highly effective in overcoming drug resistance in this disease. The findings provide new insights and innovations for advancing treatment of drug-resistant HER2-positive breast cancer that remains an unmet problem.

Correlation between ferroptosis and adriamycin resistance in breast cancer regulated by transferrin receptor and its molecular mechanism.

Breast cancer is the most prevalent malignant tumor in women. Adriamycin (ADR) is a primary chemotherapy drug, but resistance limits its effectiveness. Ferroptosis, a newly identified cell death mechanism, involves the transferrin receptor (TFRC), closely linked with tumor cells. This study aimed to explore TFRC and ferroptosis's role in breast cancer drug resistance. Bioinformatics analysis showed that TFRC was significantly downregulated in drug-resistant cell lines, and patients with low TFRC expression might demonstrate a poor chemotherapeutic response to standard treatment. High expression of TFRC was positively correlated with most of the ferroptosis-related driver genes. The research findings indicate that ferroptosis markers were higher in breast cancer tissues than in normal ones. In chemotherapy-sensitive cases, Ferrous ion (Fe2+ ) and malondialdehyde (MDA) levels were higher than in resistant cases (all p < .05). TFRC expression was higher in breast cancer than in normal tissue, especially in the sensitive group (all p < .05). Cytological experiments showed increased hydrogen peroxide (H2 O2 ) after ADR treatment in both sensitive and resistant cells, with varying MDA changes (all p < .05). Elevating TFRC increased Fe2+ and MDA in ADR-resistant cells, enhancing their sensitivity to ADR. However, TFRC upregulation combined with ADR increased proliferation and invasiveness in resistant cell lines (all p < .05). In conclusion, ADR resistance to breast cancer is related to the regulation of iron ion-mediated ferroptosis by TFRC. Upregulation of TFRC in ADR-resistant breast cancer cells activates ferroptosis and reverses ADR chemotherapy resistance of breast cancer.

Overcoming Breast Cancer Drug Resistance: A Novel Approach Using siRNA-Mediated P-glycoprotein Downregulation to Enhance Vinorelbine Efficacy.

Cancer, the second leading cause of mortality worldwide, represents a global health challenge, primarily due to drug resistance. Vinorelbine is a chemotherapeutic agent that disrupts cancer cell growth by targeting microtubules and inducing apoptosis. However, drug resistance remains a formidable obstacle. This resistance is caused by various factors including genetic mutations, drug efflux mechanisms, and DNA repair systems. Resolution of this challenge requires an innovative approach. This study investigated the potential of small interfering RNA (siRNA) to target and downregulate a vinorelbine-resistant MCF-7/ADR breast cancer cell line. Cells were cultured in Dulbecco's modified Eagle's medium (DMEM) 10% fetal bovine serum/penicillin/streptomycin. An siRNA targeting ABCB1 was designed and synthesized, and the cells were transfected with siRNA at final concentrations of 10, 20, and 30 nM. The3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess cell viability. ABCB1 mRNA expression levels were determined by real-time polymerase chain reaction (PCR). MCF-7 cells exhibited a higher sensitivity to vinorelbine than MCF-7/ADR cells. MCF-7/ADR cells exhibited resistance to vinorelbine at concentrations, 12.50 and 25.00 μM. Treatment with siRNA significantly reduced ABCB1 expression by 2.93-fold (P=0.0001). Similarly, co-treatment with siRNA and vinorelbine produced a substantial 2.89-fold decrease in ABCB1 gene expression in MCF-7 cells compared to that in MCF-7/ADR cells (P=0.0001). The results of the present study indicate that the concurrent use of siRNA and vinorelbine holds substantial promise as a therapeutic approach to overcome ABCB1-mediated multidrug resistance (MDR) in breast cancer. It is necessary to conduct comprehensive clinical trials to determine the true effectiveness of this combination therapy.

Combination Treatment with EGFR Inhibitor and Doxorubicin Synergistically Inhibits Proliferation of MCF-7 Cells and MDA-MB-231 Triple-Negative Breast Cancer Cells In Vitro.

The role of the epidermal growth factor receptor (EGFR) in tumor progression and survival is often underplayed. Its expression and/or dysregulation is associated with disease advancement and poor patient outcome as well as drug resistance in breast cancer. EGFR is often overexpressed in breast cancer and particularly triple-negative breast cancer (TNBC), which currently lacks molecular targets. We examined the synergistic potential of an EGFR inhibitor (EGFRi) in combination with doxorubicin (Dox) in estrogen-positive (ER+) MCF-7 and MDA-MB-231 TNBC cell lines. The exposure of MDA-MB-231 and MCF-7 to EGFRi produced an IC50s of 6.03 µM and 3.96 µM, respectively. Dox induced MDA-MB-231 (IC50 9.67 µM) and MCF-7 (IC50 1.4 µM) cytotoxicity. Combinations of EGFRi-Dox significantly reduced the IC50 in MCF-7 (0.46 µM) and MBA-MB 231 (0.01 µM). Synergistic drug interactions in both cell lines were confirmed using the Bliss independence model. Pro-apoptotic Caspase-3/7 activation occurred in MCF-7 at 0.1-10 µM of EGFRi and Dox single treatments, whilst 1 μM Dox yielded a more potent effect on MDA-MB-231. EGFRi and Dox individually and in combination downregulated the EGFR gene expression in MCF-7 and MDA-MB-231 (p < 0.001). This study demonstrates EGFRi's potential for eliciting synergistic interactions with Dox, causing enhanced growth inhibition, apoptosis induction, and downregulation of EGFR in both cell lines.

Catalysts of Healing: A Symphony of Synthesis and Clinical Artistry in Small-Molecule Agents for Breast Cancer Alleviation.

Breast cancer, characterized by its molecular intricacy, has witnessed a surge in targeted therapeutics owing to the rise of small-molecule drugs. These entities, derived from cutting-edge synthetic routes, often encompassing multistage reactions and chiral synthesis, target a spectrum of oncogenic pathways. Their mechanisms of action range from modulating hormone receptor signaling and inhibiting kinase activity, to impeding DNA damage repair mechanisms. Clinical applications of these drugs have resulted in enhanced patient survival rates, reduction in disease recurrence, and improved overall therapeutic indices. Notably, certain molecules have showcased efficacy in drug-resistant breast cancer phenotypes, highlighting their potential in addressing treatment challenges. The evolution and approval of small-molecule drugs have ushered in a new era for breast cancer therapeutics. Their tailored synthetic pathways and defined mechanisms of action have augmented the precision and efficacy of treatment regimens, paving the way for improved patient outcomes in the face of this pervasive malignancy. The present review embarks on a detailed exploration of small-molecule drugs that have secured regulatory approval for breast cancer treatment, emphasizing their clinical applications, synthetic pathways, and distinct mechanisms of action.

Analyses of hypoxia-related risk factors and clinical relevance in breast cancer.

Hypoxia plays an important role in the heterogeneity, relapse, metastasis, and drug resistance of breast cancer. In this study, we explored the hypoxia-related biological signatures in different subtypes of breast cancer and identified the key prognostic factors by bioinformatics methods. Based on The Cancer Genome Atlas (TCGA) Breast Cancer datasets, we divided the samples into immune-activated/suppressed populations by single-sample gene set enrichment analysis (ssGSEA) and then used hierarchical clustering to further identify hypoxic/non-hypoxic populations from the immune-suppressed samples. A hypoxia related risk model of breast cancer was constructed. Nuclear factor interleukin-3 regulated (NFIL3), serpin family E member 1 (SERPINE1), FOS, biglycan (BGN), epidermal growth factor receptor (EGFR), and sushi-repeat-containing protein, X-linked (SRPX) were identified as key hypoxia-related genes. Margin status, American Joint Committee on Cancer (AJCC) stage, hypoxia status, estrogen receptor/progesterone receptor (ER/PR) status, NFIL3, SERPINE1, EGFR, and risk score were identified as independent prognostic indicators for breast cancer patients. The 3- and 5-year survival curves of the model and immunohistochemical staining on the breast cancer microarray verified the statistical significance and feasibility of our model. Among the different molecular types of breast cancer, ER/PR+ and HER2+ patients might have higher hypoxia-related risk scores. ER/PR-negative samples demonstrated more activated immune-related pathways and better response to most anticancer agents. Our study revealed a novel risk model and potential feasible prognostic factors for breast cancer and might provide new perspectives for individual breast cancer treatment.

Rapid and automatic phenotyping of cells through their annexin-mediated enforced blebbing response

Cellular blebbing has been widely recognized as a hallmark of processes such as apoptosis and cell migration. Here, we developed a novel double-layer compression microfluidic device to trigger the enforced blebbing of cells in a programmable manner. It was found that the critical compression for inducing membrane bleb in highly invasive or drug-resistant breast and lung cancer cell lines could be several times higher than that of their non-invasive or drug-sensitive counterparts. Furthermore, we showed that knockdown of annexin-6, a protein known to be heavily involved in membrane and calcium dynamics in cells, led to a significantly reduced cellular volume, reflecting a lowered intracellular pressure, and an ∼twofold increase in the critical compressive strain for triggering blebbing. The fact that hundreds of cells can be tested and automatically analyzed in our device at the same time highlights the potential of this simple and label-free method in applications such as cell sorting and disease detection.

Co-treatment With Aripiprazole and Vincristine Sensitizes P-Glycoprotein-Overexpressing Drug-resistant MCF-7/ADR Breast Cancer Cells.

Evidence supports that use of aripiprazole sensitizes drug-resistant oral cancer cells. The aim of the study was to investigate whether aripiprazole can achieve sensitization of highly drug-resistant breast cancer cells, as well as identify its relevant mechanisms of action. MCF-7/ADR, KB, and KBV20C breast cancer cells were treated with aripiprazole, vincristine (VIC), vinorelbine, vinblastine and their combination. Cell viability assay, annexin V analyses, cellular morphology and density observation with a microscope, western-blotting, fluorescence-activated cell sorting (FACS), and analysis for P-gp inhibitory activity were performed to investigate the drugs' mechanism of action. We found that high drug resistance in MCF-7/ADR cells results from high P-gp inhibitory activity via overexpression of P-gp. Aripiprazole reduced cell viability, increased G2 arrest, and upregulated apoptosis when used as a co-treatment with VIC. Furthermore, we demonstrated that co-treatment with vinorelbine and vinblastine increased the sensitization of MCF-7/ADR breast cancer cells to aripiprazole. We confirmed that VIC-aripiprazole combination has much higher sensitization effects than either VIC-thioridazine or VIC-trifluoperazine co-treatment in MCF-7/ADR cells, since the previously known bipolar drugs (thioridazine and trifluoperazine) has lower P-gp inhibitory activity. However, aripiprazole-induced sensitization was not observed in VIC-treated MDA-MB-231 breast cancer cells suggesting that combination therapy with aripiprazole is specific for P-gp-overexpressing drug-resistant breast cancer cells. Co-treatment with low doses of aripiprazole sensitized MCF-7/ADR cells to VIC. Combination therapy with aripiprazole may be a valuable tool for delaying or reducing cancer recurrence by targeting P-gp-overexpressing drug-resistant breast cancer cells.

Pitavastatin induces autophagy-dependent ferroptosis in MDA-MB-231 cells via the mevalonate pathway

Triple-negative breast cancer (TNBC) is more prone to recurrence and metastasis relative to other subtypes of breast cancer, leading to an extremely poor prognosis. The increasing potential chemoresistance of TNBC patients is mainly due to that tumor cells escape from apoptosis. In recent years, statins have demonstrated extensive anti-tumor effects. It is worth noting that statins have more effective anti-tumor effects on TNBC cells and drug-resistant breast cancer cells. Therefore, this study examines the superior cytotoxic effects of statins on TNBC cell lines and further explores their potential therapeutic mechanisms. We detected different cell phenotypes and found that statins significantly reduced the cell viability of TNBC cells. Specifically, pitavastatin showed an obvious induction in cell death, cell cycle arrest and oxidative stress in TNBC MDA-MB-231 cells. The reversal effect of iron chelator desferrioxamine (DFO) on the morphological and molecular biological changes induced by pitavastatin has revealed a new mode of cell death induced by pitavastatin: ferroptosis. This ferroptotic effect was strengthened by the decreased expression of glutathione peroxidase 4 (GPx4) as well as newly discovered ferroptosis suppressor protein 1 (FSP1). The data showed that ferroptotic death of MDA-MB-231 cells is autophagy-dependent and mediated by the mevalonate pathway. Finally, we found that therapeutic oral doses of statins can inhibit the growth of transplanted tumors, which establishes statins as a potential treatment for TNBC patients. In conclusion, we found pitavastatin could induce autophagy-dependent ferroptosis in TNBC cells via the mevalonate pathway which may become a potential adjuvant treatment option for TNBC patients.

Low levels of sex hormone-binding globulin predict an increased breast cancer risk and its underlying molecular mechanisms.

Sex hormone-binding globulin (SHBG) is a serum glycoprotein exhibiting the unique feature of binding sex steroids with high affinity and specificity. Over the past few decades, there have been significant breakthroughs in our understanding of the function and regulation of SHBG. The biological role of SHBG has expanded from being considered a simple sex hormone transporter to being associated with several complex physiological and pathological changes in a variety of target tissues. Many factors can affect the plasma SHBG levels, with fluctuations in circulating levels affecting the development of various diseases, such as increasing the risk of developing breast cancer. This article reviews the clinical significance of changes in circulating SHBG levels in the development of breast cancer and the possible influence of these levels on endocrine drug resistance in hormone receptor-positive breast cancer. Higher levels of plasma SHBG significantly reduce the risk of estrogen receptor-positive breast cancer, especially in postmenopausal women. Moreover, the molecular mechanisms by which SHBG affects breast cancer risk are also summarized in detail. Finally, transcriptomics and proteomics data revealed that SHBG expression in breast tissue can effectively distinguish breast cancer from normal tissue. Additionally, the association between SHBG expression levels and various classical tumor-related pathways was investigated.