Cancer Stem Cell Properties Research Articles

Role of the CTCF/p300 axis in osteochondrogenic-like differentiation of polyploid giant cancer cells with daughter cells

BackgroundPolyploid giant cancer cells (PGCCs) have properties of cancer stem cells (CSCs). PGCCs with daughter cells (PDCs) undergo epithelial–mesenchymal transition and show enhanced cellular plasticity. This study aimed to elucidate the mechanisms underlying the osteo/chondrogenic-like differentiation of PDCs, which may be exploited therapeutically by transdifferentiation into post-mitotic and functional cells.MethodsCobalt chloride was used to induce PGCC formation in MDA-MB-231 and HEY cells, and PDCs were cultured in osteo/chondrogenic differentiation media. Alcian blue staining was used to confirm osteo/chondrogenic differentiation, and the cell cycle was detected using flow cytometry. The expression of osteo/chondrogenic differentiation-related proteins was compared, and a co-immunoprecipitation assay was used to demonstrate the interactions between proteins. Bioinformatic analysis was used to explore the regulatory mechanism of osteo/chondrogenic differentiation, and a dual-luciferase reporter assay was performed to validate the interaction between transcriptional factors and target genes. Animal xenograft models were used to confirm the osteo/chondrogenic differentiation of PDCs.ResultsWhen cultured in osteo/chondrogenic medium, the stemness of PDCs decreased, and the expression of osteo/chondrogenic-related markers increased. This osteo/chondrogenic-like process was regulated by the transforming growth factor-β pathway in a time-dependent manner. A concurrent increase in the expression of histone acetyltransferase p300 and the transcription factor CCCTC-binding factor (CTCF) was observed. Co-immunoprecipitation assays revealed that p300 acetylated the osteo/chondrogenic marker RUNT-related transcription factor 2 (RUNX2). Analysis of chromatin immunoprecipitation sequencing datasets revealed that both CTCF and histone H3 lysine 27 acetylation (H3K27ac) were enriched in the promoter region of E1A-associated protein p300 (P300). The four predicted binding sites for CTCF and P300 were validated using dual-luciferase reporter assays. We examined the interaction between CTCF and H3K27ac and found that these two proteins had a combined effect on the transactivation of P300.ConclusionCTCF, in synergy with H3K27ac, amplified the expression of P300, facilitating acetyl group transfer to RUNX2. This acetylation stabilized RUNX2 and promoted osteo/chondrogenic differentiation, thereby reducing the incidence of PDC malignancies.

The Anti-Cancer Stem Cell Properties of Copper(II)-Terpyridine Complexes with Attached Salicylaldehyde Moieties.

We report the synthesis, characterisation, and anti-breast cancer stem cell (CSC) properties of two copper(II)-terpyridine complexes with bidentate salicylaldehyde moieties (2-hydroxybenzaldehyde for 1 and 2-hydroxy-1-naphthaldehyde for 2). The copper(II)-terpyridine complexes 1 and 2 are stable in biologically relevant aqueous solutions and display micromolar potency towards breast CSCs. The most effective complex 1 is 5-fold and 6.6-fold more potent towards breast CSCs than salinomycin and cisplatin, respectively. The copper(II)-terpyridine complexes 1 and 2 also decrease the formation and viability of three-dimensionally cultured mammospheres within the micromolar range. Notably complex 1 is up to 7-fold more potent towards mammospheres than salinomycin or cisplatin. Mechanistic studies suggest that the copper(II)-terpyridine complexes 1 and 2 are able to readily enter breast CSCs, elevate intracellular reactive oxygen species levels, induce DNA damage (presumably by oxidative DNA cleavage), and evoke apoptosis that is independent of caspases. This study shows that the copper(II)-terpyridine motif is a useful building block for the design of anti-breast CSC agents and reinforces the therapeutic potential of copper coordination complexes.

Quercetin inhibits endothelial & hepatocellular carcinoma cell crosstalk via reducing extracellular vesicle-mediated VEGFR2 mRNA transfer.

This study aims to investigate the regulatory effects of quercetin extracellular vesicles (EVs)-mediated expression of vascular endothelial growth factor receptor 2 (VEGFR2) in hepatocellular carcinoma (HCC)-derived circulating tumor cells (CTCs) and the underlying mechanisms. CTCs were isolated from patients with pathologically diagnosed HCC, with VEGFR2 expression visualized by fluorescence in situ hybridization (FISH). The human HCC cell line Huh-7 and SK-HEP-1 were used for in vitro studies to assess EVs uptake, VEGFR2 mRNA transfer, invasion, migration, cancer stem cell (CSC) properties, and VEGF secretion. Results showed that VEGFR2 mRNA was commonly expressed in HCC-CTCs, with a higher incidence in biphenotypic CTCs. Its expression was limited in HCC cell lines, but present in certain liver cells. In vitro experiments confirmed that VEGFR2 mRNA could be transferred to HCC cells via EVs from primary tumor endothelial cells (PTECs), which was impaired by quercetin treatment. Quercetin significantly reduced VEGFR2 mRNA and protein expression in HCC cells, weakened their invasive and metastatic capacities, and diminished VEGFR2-mediated CSC properties. In vivo, quercetin reduced VEGF secretion, impaired angiogenesis, slowed tumor growth, and decreased the number and proportion of VEGFR2-positive CTCs. In summary, VEGFR2 mRNA is present in HCC-CTCs, potentially sourced from PTECs-derived EVs. Quercetin effectively inhibits VEGFR2 expression, impacting HCC cell invasion, metastasis, and CSC characteristics. Besides, it reduces VEGFR2-positive CTCs in vivo. These effects support its therapeutic potential in HCC treatment by targeting the angiogenesis and tumor dissemination pathway.

Comparative Analysis of Transcription Factors TWIST2, GATA3, and HES5 in Glioblastoma Multiforme : Evaluating Biomarker Potential and Therapeutic Targets Using In Silico Methods.

Glioblastoma multiforme (GBM) is characterized by substantial heterogeneity and limited therapeutic options. As molecular approaches to central nervous system (CNS) tumors have gained prominence, this study examined the roles of three genes, TWIST2, GATA3, and HES5, known to be involved in oncogenesis, developmental processes, and maintenance of cancer stem cell properties, which have not yet been extensively studied in GBM. This study is the first to present gene expression data for TWIST2, GATA3, and HES5 specifically within the context of GBM patient survival. Gene expression data for TWIST2, GATA3, and HES5 were collected from GBM and normal brain tissues using datasets from The Cancer Genome Atlas (TCGA) via the Genomic Data Commons (GDC) portal and the Genotype-Tissue Expression (GTEx) database. These data were rigorously analyzed using in silico methods. All three genes were significantly more expressed in GBM tissues than in normal tissues. TWIST2 and GATA3 were linked to lower survival rates in GBM patients. Interestingly, higher HES5 levels were associated with better survival rates, suggesting a complex role that needs more investigation. This study shows that TWIST2, GATA3, and HES5 could help predict outcomes in GBM patients. Our multigene model offers a better understanding of GBM and points to new treatment options, bringing hope for improved therapies and patient outcomes. This research advances our knowledge of GBM and highlights the potential of molecular diagnostics in oncology.

Chronic exposure to hexavalent chromium induces esophageal tumorigenesis via activating the Notch signaling pathway.

Hexavalent chromium Cr(VI), as a well-established carcinogen, contributes to tumorigenesis for many human cancers, especially respiratory and digestive tumors. However, the potential function and relevant mechanism of Cr(VI) on the initiation of esophageal carcinogenesis are largely unknown. Here, immortalized human esophageal epithelial cells (HEECs) were induced to be malignantly transformed cells, termed HEEC-Cr(VI) cells, via chronic exposure to Cr(VI), which simulates the progress of esophageal tumorigenesis. In vitro and in vivo experiments demonstrated that HEEC-Cr(VI) cells obtain the ability of anchorage-independent growth, greater proliferative capacity, cancer stem cell properties, and the capacity to form subcutaneous xenografts in BALB/c nude mice when compared to their parental cells, HEECs. Additionally, HEEC-Cr(VI) cells exhibited weakened cell motility and enhanced cell adhesion. Interestingly, HEECs with acute exposure to Cr(VI) failed to display those malignant phenotypes of HEEC-Cr(VI) cells, suggesting that Cr(VI)‍-induced malignant transformation, but not Cr(VI) itself, is the cause for the tumor characteristics of HEEC-Cr(VI) cells. Mechanistically, chronic exposure to Cr(VI) induced abnormal activation of Notch signaling, which is crucial to maintaining the capacity for malignant proliferation and stemness of HEEC-Cr(VI) cells. As expected, N-‍[N-‍(3,5-difluorophenacetyl)‍-L-alanyl]‍-S-phenylglycine t-butyl ester (DAPT), an inhibitor for the Notch pathway, drastically attenuated cancerous phenotypes of HEEC-Cr(VI) cells. In conclusion, our study clarified the molecular mechanism underlying Cr(VI)‍-induced esophageal tumorigenesis, which provides novel insights for further basic research and clinical therapeutic strategies about Cr(VI)‍-associated esophageal cancer.

Clinical significance and therapeutic implication of CD200 in pancreatic cancer

BackgroundCD200, a negative regulator of T cells as well as a marker for cancer stem cells, represents a significant prognostic factor and potential therapeutic target in certain cancers. However, its clinical significance remains unknown in pancreatic ductal adenocarcinoma (PDAC). MethodsCD200 was assessed in 220 resected PDAC patients who underwent surgery with or without neoadjuvant chemoradiotherapy (NACRT). We examined the clinicopathological outcomes associated with CD200 and further assessed its clinical implications regarding immunological and cancer stem cell properties. ResultsNACRT was associated with higher CD200 expression (66.4 % vs. 32.2 %, P < 0.001) compared to upfront surgery. CD200 was identified as an independent poor prognostic factor in NACRT (hazard ratio 1.90, 95 % confidence interval 1.12–3.23, P = 0.016), but not in upfront surgery patients. Post-recurrence survival was significantly worse in CD200+ patients compared to CD200- patients in the NACRT group, but there was no significant difference observed in the upfront surgery group. CD200 expression was correlated with significantly lower levels of CD4+, CD8+, and CD45RO+ tumor-infiltrating lymphocytes. Furthermore, the correlation of CD200 with pancreatic cancer stem cell markers CD44/CD24/ESA was stronger in irradiated human pancreatic cancer cells. ConclusionsOur data underscore novel roles for CD200 in immune evasion as well as therapy resistance in pancreatic cancer. CD200 may represent a novel poor prognostic predictive factor and potential therapeutic target for PDAC with NACRT.

Fatty acid synthase inhibitor cerulenin hinders liver cancer stem cell properties through FASN/APP axis as novel therapeutic strategies

Hepatocellular carcinoma (HCC) poses significant treatment challenges due to high postoperative recurrence rates and the limited effectiveness of targeted medications. Researchers have identified the unique metabolic profiles of cancer stem cells (CSCs) as the primary drivers of cancer recurrence, metastasis, and drug resistance. Therefore, to address the therapeutic conundrum, this study focused on rewinding metabolic reprogramming of CSCs as a novel therapeutic strategy. HCC CSCs exhibited elevated fatty acid (FA) metabolism compared with parental cells. To specifically target FA metabolism in CSCs, we utilized cerulenin, a fatty acid synthase (FASN) inhibitor. Surprisingly, cerulenin can diminish CSC-like characteristics, including stemness gene expression, spherogenicity, tumorigenicity, and metastatic potential. In addition, sorafenib, a multikinase inhibitor used as targeted therapy for advanced HCC, was employed in combination with cerulenin, demonstrating a great synergistic effect, particularly in CSCs. Importantly, our RNA sequencing analysis disclosed that the amyloid protein precursor (APP) is a crucial downstream effector of FASN in regulating CSC properties. We found that APP plays a crucial role in CSCs’ characteristics that can be inhibited by cerulenin. By focusing on FA metabolism, this study identified the FASN/APP axis as a viable target to develop a more potent therapy strategy for advanced HCC.

Thermo-Responsive Hydrogel Based on Lung Decellularized Extracellular Matrix for 3D Culture Model to Enhance Cancer Stem Cell Characteristics.

Cancer stem cells (CSCs) are most likely the main cause of lung cancer formation, metastasis, drug resistance, and genetic heterogeneity. Three-dimensional (3D) ex vivo cell culture models can facilitate stemness improvement and CSC enrichment. Considering the critical role of extracellular matrix (ECM) on CSC properties, the present study developed a thermo-responsive hydrogel using the porcine decellularized lung for 3D cell culture, and the cell-laden hydrogel culturing model was used to explore the CSC characteristics and potential utilization in CSC-specific drug evaluation. Results showed that the lung dECM hydrogel (LEH) was composed of the main ECM components and displayed excellent cellular compatibility. In addition, lung cancer cells 3D cultured in LEH displayed the overexpression of metastasis-related genes and enhanced migration properties, as compared with those in two-dimensional (2D) conditions. Notably, the CSC features, including the expression level of stemness-associated genes, colony formation capability, drug resistance, and the proportion of cancer stem-like cells (CD133+), were also enhanced in 3D cells. Furthermore, the attenuation effect of epigallocatechin gallate (EGCG) on CSC properties in the 3D model was observed, confirming the potential practicability of the 3D culture on CSC-targeted drug screening. Overall, our results suggest that the fabricated LEH is an effective and facile platform for 3D cell culture and CSC-specific drug evaluation.

Blocking tumor-intrinsic MNK1 kinase restricts metabolic adaptation and diminishes liver metastasis.

Dysregulation of the mitogen-activated protein kinase interacting kinases 1/2 (MNK1/2)-eukaryotic initiation factor 4E (eIF4E) signaling axis promotes breast cancer progression. MNK1 is known to influence cancer stem cells (CSCs); self-renewing populations that support metastasis, recurrence, and chemotherapeutic resistance, making them a clinically relevant target. The precise function of MNK1 in regulating CSCs, however, remains unexplored. Here, we generated MNK1 knockout cancer cell lines, resulting in diminished CSC properties in vitro and slowed tumor growth in vivo. Using a multiomics approach, we functionally demonstrated that loss of MNK1 restricts tumor cell metabolic adaptation by reducing glycolysis and increasing dependence on oxidative phosphorylation. Furthermore, MNK1-null breast and pancreatic tumor cells demonstrated suppressed metastasis to the liver, but not the lung. Analysis of The Cancer Genome Atlas (TCGA) data from breast cancer patients validated the positive correlation between MNK1 and glycolytic enzyme protein expression. This study defines metabolic perturbations as a previously unknown consequence of targeting MNK1/2, which may be therapeutically exploited.

Exposure to endocrine disruptor DEHP promotes the progression and radiotherapy resistance of pancreatic cancer cells by increasing BMI1 expression and properties of cancer stem cells

Most patients diagnosed with pancreatic cancer are initially at an advanced stage, and radiotherapy resistance impact the effectiveness of treatment. This study aims to investigate the effects of endocrine disruptor Di-(2-ethylhexyl) phthalate (DEHP) on various biological behaviors and the radiotherapy sensitivity of pancreatic cancer cells, as well as its potential mechanisms. Our findings indicate that exposure to DEHP promotes the proliferation of various cancer cells, including those from the lung, breast, pancreas, and liver, in a time- and concentration-dependent manner. Furthermore, DEHP exposure could influence several biological behaviors of pancreatic cancer cells in vivo and vitro. These effects include reducing cell apoptosis, causing G0/G1 phase arrest, increasing migration capacity, enhancing tumorigenicity, elevating the proportion of cancer stem cells (CSCs), and upregulating expression levels of CSCs markers such as CD133 and BMI1. DEHP exposure can also increase radiation resistance, which can be reversed by downregulating BMI1 expression. In summary our research suggests that DEHP exposure can lead to pancreatic cancer progression and radiotherapy resistance, and the mechanism may be related to the upregulation of BMI1 expression, which leads to the increase of CSCs properties.

TESC associated with poor prognosis enhances cancer stemness and migratory properties in liver cancer

Liver cancer stem cells (LCSCs) are responsible for recurrence, metastasis, and drug resistance in liver cancer. However, the genes responsible for inducing LCSCs have not been fully identified. Based on our previous study, we found that tescalcin (TESC), a calcium-binding EF hand protein that plays a crucial role in chromatin remodeling, transcriptional regulation, and epigenetic modifications, was up-regulated in LCSCs of spheroid cultures. By searching the Cancer Genome Atlas, International Cancer Genome Consortium, Human Protein Atlas, and Kaplan–Meier Plotter databases, we found that TESC expression was significantly elevated in liver cancer compared with that in normal liver tissue and was predictive of a decreased overall survival rate. Multivariate Cox analysis revealed TESC to be an independent prognostic factor for survival. High TESC expression was positively associated with cancer stem cell pathways, cancer stem cell surface markers, stemness transcription factors, epithelial–mesenchymal transition (EMT) factors, immune checkpoint proteins, and various cancer-related biological processes in liver cancer. Furthermore, TESC was implicated as promoting cancer stem cell properties through its influence on EMT. We demonstrated that TESC is a novel stemness-related gene that can serve as an independent prognostic factor for liver cancer.

CD133+/ABCC5+ cervical cancer cells exhibit cancer stem cell properties

ObjectiveThis study explores the correlation between Forkhead box M1 (FOXM1) and ATP-binding cassette subfamily C member 5 (ABCC5) in relation to paclitaxel resistance in cervical cancer. It aims to identify potential cervical cancer stem cell markers, offering fresh perspectives for developing therapeutic strategies to overcome paclitaxel chemoresistance in cervical cancer. MethodsPaclitaxel-resistant Hela cells (Hela/Taxol) were developed by intermittently exposing Hela cells to progressively increasing concentrations of paclitaxel. We assessed the biological properties of both Hela and Hela/Taxol cells using various assays: cell proliferation, clonogenic, cell cycle, apoptosis, scratch, and transwell. To determine which markers better represent tumor stem cells, we analyzed various known and potential stem cell markers in combination. Flow cytometry was employed to measure the proportion of positive markers in both parental and drug-resistant cell lines. Following statistical analysis to establish relative stability, CD133+ABCC5+ cells were sorted for further examination. Subsequent tests included sphere-forming assays and Western blot analysis to detect the presence of the stem cell-specific protein Sox2, aiding in the identification of viable cervical cancer stem cell markers. ResultsThe Hela/Taxol cell line exhibited significantly enhanced proliferation, migration, and invasion capabilities compared to the Hela cell line, alongside a marked reduction in apoptosis rates (P < 0.01). Notably, proportions of CD44+, CD24+CD44+, ABCC5+, CD24+CD44+ABCC5+, CD44+ABCC5+, CD24+CD44+FOXM1+, CD44+FOXM1+, CD133+ABCC5+, and CD133+FOXM1+ were significantly higher (P < 0.05). Furthermore, the size and number of spheres formed byCD133+ABCC5+ cells were greater in the sorted Hela/Taxol line (P < 0.01), with increased expression of the stem cell marker Sox2 (P < 0.001). ConclusionThe Hela/Taxol cells demonstrate increased tumoral stemness, suggesting that CD133+ABCC5+ may serve as a novel marker for cervical cancer stem cells.

SUV39H1 Preserves Cancer Stem Cell Chromatin State and Properties in Glioblastoma.

SUV39H1 is upregulated in GBM, especially GSCsTargeting SUV39H1 disrupts GSC maintenance and sensitizes GSCs to TMZTargeting SUV39H1 alters chromatin accessibility at cell cycle and stemness genesTargeting SUV39H1 suppresses GSC-driven tumors in a patient-derived xenograft model.

The role of Lin28A and Lin28B in cancer beyond Let-7.

Lin28A and Lin28B are paralogous RNA-binding proteins that play fundamental roles in development and cancer by regulating the microRNA family of tumor suppressor Let-7. Although Lin28A and Lin28B share some functional similarities with Let-7 inhibitors, they also have distinct expression patterns and biological functions. Increasing evidence indicates that Lin28A and Lin28B differentially impact cancer stem cell properties, epithelial-mesenchymal transition, metabolic reprogramming, and other hallmarks of cancer. Therefore, it is important to understand the overexpression of Lin28A and Lin28B paralogs in specific cancer contexts. In this review, we summarize the main similarities and differences between Lin28A and Lin28B, their implications in different cellular processes, and their role in different types of cancer. In addition, we provide evidence of other specific targets of each lin28 paralog, as well as the lncRNAs and miRNAs that promote or inhibit its expression, and how this impacts cancer development and progression.

Characterization of Cancer Stem Cells in Laryngeal Squamous Cell Carcinoma by Single-cell RNA Sequencing.

Cancer stem cells (CSCs) constitute a pivotal element within the tumor microenvironment (TME), driving the initiation and progression of cancer. However, the identification of CSCs and their underlying molecular mechanisms in laryngeal squamous cell carcinoma (LSCC) remains a formidable challenge. Here, we employed single-cell RNA sequencing of matched primary tumor tissues, paracancerous tissues, and local lymph nodes from three LSCC patients to comprehensively characterize the CSCs in LSCC. Two distinct clusters of stem cells originating from epithelial populations were delineated and verified as CSCs and normal stem cells (NSCs), respectively. CSCs were abundant in the paracancerous tissues compared to those in the tumor tissues. CSCs showed high expression of stem cell marker genes such as PROM1, ALDH1A1, and SOX4, and increased the activity of tumor-related hypoxia, Wnt/β-catenin, and Notch signaling pathways. We then explored the intricate crosstalk between CSCs and the TME cells and identified targets within the TME that related with CSCs. We also found eight marker genes of CSCs that were correlated significantly with the prognosis of LSCC patients. Furthermore, bioinformatics analyses showed that drugs such as erlotinib, OSI-027, and ibrutinib selectively targeted the CSC-specifically expressed genes. In conclusion, our results represent the first comprehensive characterization of CSC properties in LSCC at the single-cell level.

MicroRNA as Key Players in Hepatocellular Carcinoma: Insights into Their Role in Metastasis.

Liver cancer or hepatocellular carcinoma (HCC) remains the most common cancer in global epidemiology. Both the frequency and fatality of this malignancy have shown an upward trend over recent decades. Liver cancer is a significant concern due to its propensity for both intrahepatic and extrahepatic metastasis. Liver cancer metastasis is a multifaceted process characterized by cell detachment from the bulk tumor, modulation of cellular motility and invasiveness, enhanced proliferation, avoidance of the immune system, and spread either via lymphatic or blood vessels. MicroRNAs (miRNAs) are small non-coding ribonucleic acids (RNAs) playing a crucial function in the intricate mechanisms of tumor metastasis. A number of miRNAs can either increase or reduce metastasis via several mechanisms, such as control of motility, proliferation, attack by the immune system, cancer stem cell properties, altering the microenvironment, and the epithelial-mesenchymal transition (EMT). Besides, two other types of non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) can competitively bind to endogenous miRNAs. This competition results in the impaired ability of the miRNAs to inhibit the expression of the specific messenger RNAs (mRNAs) that are targeted. Increasing evidence has shown that the regulatory axis comprising circRNA/lncRNA-miRNA-mRNA is correlated with the regulation of HCC metastasis. This review seeks to present a thorough summary of recent research on miRNAs in HCC, and their roles in the cellular processes of EMT, invasion and migration, as well as the metastasis of malignant cells. Finally, we discuss the function of the lncRNA/circRNA-miRNA-mRNA network as a crucial modulator of carcinogenesis and the regulation of signaling pathways or genes that are relevant to the metastasis of HCC. These findings have the potential to offer valuable insight into the discovery of novel therapeutic approaches for management of liver cancer metastasis.

Stimuli-Responsive Hydrogels Potentiating Photothermal Therapy against Cancer Stem Cell-Induced Breast Cancer Metastasis.

The self-renewal and differentiation properties of cancer stem cells (CSCs) result in chemoresistance in breast cancer. Even though numerous drugs have been developed to target CSCs, they have suffered from inefficient delivery and accumulation at the focal site. Here, a thermoresponsive hydrogel is developed by coencapsulating aggregation-induced emission (AIE)-active photothermal agent and thioridazine (THZ), demonstrating a controllable delivery system triggered by the AIE agent to augment THZ-mediated CSC ablation. Upon near-infrared laser stimuli, the photothermal effect from the AIE agent induces hydrogel deformation for burst drug release. The precise in situ tumor administration of the hydrogel accelerates drug diffusion and accumulation in deep breast cancer lesions. Thus, THZ can invade tumors and provoke massive CSC apoptosis via dopamine receptor blockage and oxidative stress induction. Consequently, effective CSC inhibition and significant suppression of tumor recurrence and metastasis are demonstrated in mice with breast cancer. We believe that this intelligent hydrogel-based delivery system represents a promising treatment strategy for metastatic breast cancer with clinical potential.

Dysregulated Wnt/β-catenin signaling confers resistance to cuproptosis in cancer cells.

Cuproptosis is characterized by the aggregation of lipoylated enzymes of the tricarboxylic acid cycle and subsequent loss of iron-sulfur cluster proteins as a unique copper-dependent form of regulated cell death. As dysregulation of copper homeostasis can induce cuproptosis, there is emerging interest in exploiting cuproptosis for cancer therapy. However, the molecular drivers of cancer cell evasion of cuproptosis were previously undefined. Here, we found that cuproptosis activates the Wnt/β-catenin pathway. Mechanistically, copper binds PDK1 and promotes its interaction with AKT, resulting in activation of the Wnt/β-catenin pathway and cancer stem cell (CSC) properties. Notably, aberrant activation of Wnt/β-catenin signaling conferred resistance of CSCs to cuproptosis. Further studies showed the β-catenin/TCF4 transcriptional complex directly binds the ATP7B promoter, inducing its expression. ATP7B effluxes copper ions, reducing intracellular copper and inhibiting cuproptosis. Knockdown of TCF4 or pharmacological Wnt/β-catenin blockade increased the sensitivity of CSCs to elesclomol-Cu-induced cuproptosis. These findings reveal a link between copper homeostasis regulated by the Wnt/β-catenin pathway and cuproptosis sensitivity, and suggest a precision medicine strategy for cancer treatment through selective cuproptosis induction.

Tumor associated macrophages in breast cancer progression: implications and clinical relevance.

Macrophages represent an immune cell population characterized by high plasticity and a range of properties and functions. Their activation status and specific phenotype are highly associated with their localization and the environmental cues they receive. The roles of macrophages in cancer development are diverse. Despite their antitumor effects at early stages of the disease, their presence in the tumor microenvironment (TME) has been linked to tumor promotion upon disease establishment. Tumor associated macrophages (TAMs) are key components of breast cancer TME and they have been associated with poor clinical outcomes. High TAM densities were found to correlate with tumor progression, increased metastatic potential and poor prognosis. Interestingly, considerably higher levels of TAMs were found in patients with triple negative breast cancer (TNBC)-the most aggressive type of breast cancer-compared to other types. The present review summarizes recent findings regarding the distinct TAM subsets in the TME and TAM involvement in breast cancer progression and metastasis. It highlights the constant interplay between TAMs and breast cancer cells and its major contribution to the progression of the disease, including such aspects as, polarization of macrophages toward a tumor promoting phenotype, induction of epithelial to mesenchymal transition (EMT) in cancer cells and enhancement of cancer stem cell properties. Further, we discuss the clinical relevance of these findings, focusing on how a better delineation of TAM involvement in breast cancer metastasis will facilitate the selection of more efficient treatment options.

Evaluation of Boric Acid Treatment on microRNA-127-5p and Metastasis Genes Orchestration of Breast Cancer Stem Cells.

Coregulation of microRNAs (miRNAs) and cancer stem cells (CSCs) is very important in carcinogenesis. miR-127-5p is known to be downregulated in breast cancer. In this study, we aimed to investigate how boric acid (BA), known for its previously unstudied anti-cancer properties, would affect the expression of miR127-5p and genes responsible for breast cancer stem cells (BC-SCs) metastasis. BC-SCs were isolated from human breast cancer cells (MCF-7) by immunomagnetic cell separation and characterized with flow cytometry and sphere formation. The viability of BC-SCs and the determination of its IC50 value in response to boric acid (BA) were assessed via the MTT assay. Boric acid exhibited dose- and time-dependent inhibition of cell viability in cells. The IC50 doses of boric acid in MCF-7 cells and BC-SCs were 45.69mM and 41.27mM, respectively. The impact of BA on the expression of metastatic genes and miR127-5p was elucidated through RT-qPCR analysis. While the expression of the COL1A1 (p < 0.05) and VIM (p < 0.01) was downregulated, the expression of the miR-127-5p, ZEB1 (p < 0.01), CDH1 (p < 0.05), ITGB1 (p < 0.05), ITGA5 (p < 0.05), LAMA5 (p < 0.01), and SNAIL (p < 0.05), was up-regulated in dose-treated BC-SCs (p < 0.001) to the RT-qPCR results. Our findings suggest that boric acid could induce miR-127-5p expression. However, it cannot be said that it improves the metastasis properties of breast cancer stem cells.