Search Results (823)

Breast cancer is one of the most common cancers globally. Unfortunately, many patients with breast cancer develop resistance to chemotherapy and tumor recurrence, which is primarily driven by breast cancer stem cells (BCSCs). BCSCs behave like stem cells and can self-renew and differentiate into mature tumor cells, enabling the cancer to regrow and metastasize. Key markers like CD44 and aldehyde dehydrogenase-1 (ALDH1), along with pathways like Wingless-related integration site (Wnt), Notch, and Hedgehog, are critical to regulating this stem-like behavior of BCSCs and, thus, are being investigated as targets for various new therapies. This review summarizes marker-dependent strategies for targeting BCSCs and expands on the challenges for the development of anti-BCSC drugs. We explore cutting-edge approaches like artificial intelligence (AI)-driven drug discovery and urge readers to seriously consider biological clocks and chronotherapy as experimental variables in drug discovery. Collectively, the task of cancer researchers is to overcome the many hurdles targeting BCSCs if we hope to tangibly improve breast cancer treatment outcomes and reduce mortality. Full article

Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a key regulator of cancer stem cell (CSC) biology and signaling. In CSCs, ROR1 acts as a receptor or co-receptor, interacting with non-canonical WNT ligands, and forming complexes with proteins like CD19 and HER2, to activate diverse downstream signaling pathways. ROR1 signaling in CSCs promotes proliferation, maintains stemness, and enhances migration, invasion, and the epithelial-to-mesenchymal transition (EMT). While minimally expressed after embryogenesis, ROR1 is aberrantly upregulated in numerous cancers, including ovarian, breast, pancreatic, and hematologic malignancies. ROR1 overexpression drives tumor progression, resistance to chemotherapies, disease recurrence, and ultimately metastasis. This expression pattern positions ROR1 as a promising target for CSC-specific therapies. High ROR1 expression is consistently linked to aggressive disease and poor patient outcomes. Here, we review ROR1′s role in CSCs and highlight the complex signaling that is observed in the CSC population. Further, we evaluate the gaps in the current understanding of ROR1 signaling in CSCs and describe how ROR1 regulates the associated signaling pathways. Finally, we provide an up-to-date summary of the promising therapeutic strategies targeting ROR1 that overcome conventional cancer treatment limitations. This review highlights the role of ROR1 as a critical, functional driver of CSCs and adverse patient outcomes across various malignancies. Full article

This investigation examines the function of the mouse Mycn gene in regulating and activating quiescent mammary stem cells, which are vital for mammary gland development. The mammary gland, consisting of luminal and basal cells, progresses through complex developmental stages from embryonic development through puberty, adulthood, pregnancy, lactation, and involution. Quiescent stem cells, existing in a reversible non-proliferative state, are essential for gland maintenance, yet their activation mechanisms remain poorly understood. Mycn, a member of the Myc/MYC oncogene family, is recognized for its roles in embryonic development and cancer, notably aggressive neuroblastoma and triple-negative breast cancer. Through single-cell RNA sequencing (scRNA-seq), CRISPR knockout, and overexpression experiments, this study demonstrates that Mycn is highly enriched in the terminal end buds (TEBs) of the pubertal mammary gland, particularly in basal cells, and is critical for ductal development. Both deletion and overexpression of Mycn diminish the stemness and regenerative capacity of mammary stem cells. Mycn enhances cell proliferation while downregulating quiescent stem cell markers and regulators, including Bcl11b and Tspan8, affecting stem cell maintenance and differentiation. This research clarifies the regulatory role of Bcl11b in controlling Tspan8 expression and demonstrates that Mycn indirectly targets both under normal conditions. Maintaining appropriate levels of Mycn expression is essential for normal development and cancer prevention. These insights contribute to understanding diseases and aggressive cancers, including triple-negative breast cancer (TNBC), and suggest potential therapeutic approaches. Full article

Background and objectives: Chemotherapy is an established treatment modality for breast cancer; however, it is impaired by issues such as highly refractory chemoresistance and significant side effects. Magnesium ions (Mg²⁺), inorganic metal ions with anti-tumor bioactivity, sensitize cancer cells to chemotherapy by depressing P-glycoprotein (P-gp) expression. Moreover, Mg²⁺ functions as an immunoadjuvant to potentiate anti-tumor immune responses, while excessive Mg²⁺ can induce marked tumor cell apoptosis. Methods: To enable Mg²⁺ to serve as a chemotherapeutic adjuvant for enhanced treatment efficacy, a Trojan horse-like chemoamplifier, denoted as MMSN@Dox, endowed with tumor microenvironment (TME) responsiveness and capable of achieving chemotherapy sensitization and anti-tumor immune activation, was constructed to enhance the efficacy of breast cancer treatment. Leveraging Mg²⁺-enabled TME-responsive degradability of the chemoamplifier, density functional theory (DFT) simulations were conducted to elucidate carrier structural dynamics. Results: Under stimulation of TME, the chemoamplifier decomposes, accompanied by a substantial release of chemotherapeutic agents and metal ions. Excessive Mg²⁺ induces significant tumor cell apoptosis by triggering mitochondrial dysfunction and generating reactive oxygen species (ROS), and reinforces chemotherapy sensitivity by depressing P-gp expression. Furthermore, MMSN@Dox weakens the stemness of tumor cells, further enhancing chemotherapy. The remarkable tumor-killing capability of chemoamplifier MMSN@Dox led to a remarkable immunogenic cell death (ICD) effect. Combined with the regulatory function of Mg²⁺ on T cells, it ultimately activates anti-tumor immune responses and achieves exceptional anti-tumor performance in both in vitro and in vivo models. Conclusions: This approach, leveraging Mg²⁺ to enhance chemotherapy efficacy, establishes a new paradigm for overcoming chemotherapy resistance and offers a novel strategic avenue for advancing nanomedicine in breast cancer treatment. Full article

Chemoresistance is a major challenge in the treatment of triple-negative breast cancer (TNBC). Multicellular spheroids are an attractive platform for investigating chemoresistance in TNBC, as they replicate the cues of the tumour microenvironment in vivo. We conducted a comprehensive literature search to summarise the multifactorial and interlinked mechanisms driving chemoresistance in TNBC spheroids. These mechanisms include spatial heterogeneity, hypoxia, extracellular matrix remodelling, tumour–stroma crosstalk, drug efflux, apoptotic resistance, and cancer stem cell signalling. Strategies for overcoming chemoresistance in TNBC spheroids include nanocarrier systems to overcome spatial diffusion limitations, pathway inhibition, and targeting tumour–microenvironment interactions. Despite their advantages, some spheroid models face challenges such as low reproducibility, a lack of heterogeneity, variability in size and shape, limited vascularisation, and constraints in long-term culture. Advanced culturing platforms such as clinostat bioreactors allow for extended culture periods, enabling mature spheroid drug testing. Furthermore, advanced analytical techniques provide spatially resolved spheroid data. These multifactorial and interlinked mechanisms reflect the tumour microenvironment in vivo that spheroids recapitulate, rendering them valuable models for studying chemoresistance. The incorporation of stromal components and advanced analytical workflows will enhance the utility and translational relevance of spheroids as reliable preclinical models for drug discovery in TNBC. Full article

Breast cancer remains one of the most prevalent malignancies worldwide, and radiation therapy is a central component of its management. However, intrinsic or acquired resistance to radiation significantly compromises therapeutic efficacy. This systematic review aimed to identify and evaluate molecular mechanisms and interventions that influence radiation sensitivity in breast cancer models. A comprehensive PubMed search was conducted using the terms “breast cancer” and “radiation resistance” for studies published between 2002 and 2024. Seventy-nine eligible studies were included. The most frequently investigated mechanisms included the dysregulation of the PI3K/AKT/mTOR and MAPK signaling pathways, enhanced DNA damage repair via non-homologous end joining (NHEJ), and the overexpression of cancer stem cell markers such as CD44⁺/CD24⁻/low and ALDH1. Several studies highlighted the role of non-coding RNAs, particularly the lncRNA DUXAP8 and microRNAs such as miR-21, miR-144, miR-33a, and miR-634, in modulating radiation response. Components of the tumor microenvironment, including cancer-associated fibroblasts and immune regulators, also contributed to radiation resistance. By synthesizing current evidence, this review provides a consolidated resource to guide future mechanistic studies and therapeutic development. This review highlights promising molecular targets and emerging strategies to enhance radiosensitivity and offers a foundation for translational research aimed at improving outcomes in radiation-refractory breast cancer. Full article

Docetaxel is a chemotherapeutic agent widely used for breast cancer treatment; however, its efficacy is often limited by drug resistance and associated toxicity. This review examines the molecular mechanisms of docetaxel resistance in breast cancer and discusses research advances and future directions for overcoming this challenge. Key resistance mechanisms include alterations in drug targets (microtubules), increased drug efflux, suppression of apoptosis, activation of survival signalling pathways, epithelial-to-mesenchymal transition (EMT), and cancer stem cell enrichment. An evolutionary perspective distinguishes between intrinsic and acquired resistance, emphasising the need for adaptive therapeutic strategies. Recent advances in genomic profiling, non-coding RNA research, novel drug combinations, and biomarker-guided therapies have also been reviewed. Emerging approaches, such as targeting the tumour microenvironment, harnessing immunotherapy, and implementing adaptive dosing schedules, have been discussed. This review emphasises the understanding of resistance as a multifactorial phenomenon that requires multipronged interventions. Research has aimed to identify predictive biomarkers, develop targeted agents to reverse resistance, and design rational combination strategies to improve patient outcomes. Progress in deciphering and targeting docetaxel resistance mechanisms holds promise for enhancing treatment responses and extending survival in patients with breast cancer. Full article

Snail and Zeb1 have been suggested as markers for the hybrid/mixed epithelial (E)/mesenchymal (M) state of cancer cells. Such cancer cells co-express E- and M-specific transcripts and possess cancer stem cell properties. M13HS-2/-8 tumor hybrid clones derived from human M13SV1-EGFP-Neo breast epithelial cells and human HS578T-Hyg breast cancer cells exhibited co-expression of Snail and Zeb1. To explore the impact of Snail on stemness/epithelial-to-mesenchymal transition (EMT)-related properties in M13HS-2/-8 tumor hybrid clones, Snail was knocked out (KO) using CRISPR/Cas9. Mammosphere formation, colony formation, Western blot analyses, cell migration, and invasion assays were conducted for the characterization of Snail knockout cells. Interestingly, Snail-KO in M13SV1-EGFP-Neo cells resulted in the up-regulation of vimentin and N-cadherin, suggesting EMT induction, which was associated with a significantly enhanced colony formation capacity. In contrast, EMT marker pattern and colony formation capacities of M13HS-2/-8 Snail-KO tumor hybrid clones remained unchanged. Notably, the mammosphere formation capacities of M13HS-2/-8 Snail-KO tumor hybrid clones were significantly reduced. The migratory behavior of all Snail-KO cells was not altered compared with their wild-type counterparts. In contrast, M13HS-2 hybrids and their M13HS-2 Snail-KO variant exhibited a markedly enhanced invasive capacity. Therefore, Snail plays a role as a mediator of stemness properties rather than mediating EMT. Full article

Regulatory T cells (Tregs) have multiple roles in the tumor microenvironment (TME), which maintain a balance between autoimmunity and immunosuppression. This research aimed to investigate the interaction between cancer stemness and Regulatory T cells (Tregs) in the breast cancer tumor immune microenvironment. Breast cancer stemness was calculated using one-class logistic regression. Twelve main cell clusters were identified, and the subsequent three subsets of Regulatory T cells with different differentiation states were identified as being closely related to immune regulation and metabolic pathways. A prognostic risk model including MEA1, MTFP1, PASK, PSENEN, PSME2, RCC2, and SH2D2A was generated through the intersection between Regulatory T cell differentiation-related genes and stemness-related genes using LASSO and univariate Cox regression. The patient’s total survival times were predicted and validated with AUC of 0.96 and 0.831 in both training and validation sets, respectively; the immunotherapeutic predication efficacy of prognostic signature was confirmed in four ICI RNA-Seq cohorts. Seven drugs, including Ethinyl Estradiol, Epigallocatechin gallate, Cyclosporine, Gentamicin, Doxorubicin, Ivermectin, and Dronabinol for prognostic signature, were screened through molecular docking and found a synergistic effect among drugs with deep learning. Our prognostic signature potentially paves the way for overcoming immune resistance, and blocking the interaction between cancer stemness and Tregs may be a new approach in the treatment of breast cancer. Full article

Background/Objective: Cancer stem cells (CSCs) are a self-renewing subpopulation within tumors that contribute to heterogeneity and resistance to conventional cancer therapies, including chemotherapy and radiotherapy. Despite growing interest in CSCs as therapeutic targets, effective compounds against these cells remain limited. This systematic review aims to assess the potential of metal-based coordination complexes as anti-CSC agents in preclinical models. Methods: A systematic literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Twenty-seven original in vitro studies were included, all evaluating the cytotoxic effects of metal-based compounds on cancer cell lines enriched with CSC subpopulations. To ensure methodological rigor, all articles underwent a critical appraisal by independent reviewers who resolved discrepancies through consensus, and only studies meeting predefined quality criteria were included. Results: Several metal complexes, particularly copper-based compounds, demonstrated significant cytotoxicity toward CSCs, mainly through the induction of apoptosis. Breast cancer was the most frequently studied tumor type. Many studies reported modulation of CSC-related markers, including EPCAM, CD44, CD133, CD24, SOX2, KLF4, Oct4, NOTCH1, ALDH1, CXCR4, and HES1, suggesting effects on CSC maintenance pathways. Most studies were conducted in the United Kingdom and relied on in vitro models. Conclusions: Metal coordination complexes, especially those containing copper, show promise as therapeutic agents targeting CSCs. However, further in vivo studies and mechanistic investigations are essential to advance their translational potential. Full article

Rumex confertus (RC), a plant known for its traditional medicinal uses, has shown potential anticancer properties, particularly due to its rich phenolic content. Despite its promising bioactivity, its effects on breast cancer cells remain underexplored. Here, we investigated the cytotoxic effects of RC extracts on MCF-7 breast cancer cells, employing various solvents for extraction. This study revealed that the hexane extract significantly reduced the cell viability, with an IC₅₀ of 9.40 µg/mL after 96 h. The gene expression analysis indicated a substantial modulation of transcriptional networks, including the upregulation of pluripotency-related genes and the downregulation of differentiation markers. The findings suggest that the RC extract may induce a shift towards a less differentiated, stem-like state in cancer cells, potentially enhancing malignancy resistance. This study underscores the potential of RC as a candidate for breast cancer treatment, and a further investigation into its therapeutic applications is suggested. Full article

Background/Objectives: Bisphenol A (BPA) is found throughout the environment and exposure to it has been shown to cause several health problems, including cancer. The problem with BPA is that it is a xenoestrogen that is chemically very similar to 17β-estradiol. Chronic exposure to BPA overstimulates the estrogen receptors and leads to inflammation that triggers several pathways leading to cancer progression. This is especially true in the case of hormone-sensitive breast cancers. This article reviewed the main pathways thought to be involved in the formation and/or progression of the most common forms of hormone-sensitive breast cancers due to BPA exposure. The main results were compiled and presented in tables along with a more detailed discussion of each pathway within the text. In most cases, chronic BPA exposure led to inflammation, which then triggered pathways leading to cancer stem cell formation and maintenance. In other cases, BPA exposure led to the formation of reactive oxygen species that damaged DNA and caused the formation of mutated p53 and tumorigenesis. Conclusions: The article summarizes the key pathways that are currently known, pertaining to how BPA leads to the progression and maintenance of breast cancer. The article then concludes by discussing how prenatal and perinatal BPA exposure may also predispose women to hormone-sensitive breast cancers later in life. Full article

According to the WHO, in 2022, there were 2.3 million women diagnosed with breast cancer (BC) and 670,000 deaths globally. BC remains the leading cause of cancer-related mortality, with therapeutic resistance representing a significant barrier to effective treatment, particularly in aggressive subtypes like triple-negative breast cancer (TNBC). This review article discusses emerging strategies to overcome resistance by integrating precision oncology, nanotechnology-based drug delivery, and immune modulation. Resistance mechanisms—such as metabolic reprogramming, tumor heterogeneity, immune evasion, autophagy, and the role of cancer stem cells—are critically examined. We highlight cutting-edge nanoplatforms that co-deliver chemotherapeutics and immune stimulants with spatiotemporal precision, including sonodynamic and photothermal systems, ADCs, and targeted nanoparticles. Moreover, advances in tumor microenvironment (TME) modulation, photoimmunotherapy, and exosomal miRNA targeting offer promising avenues to enhance immunogenicity and therapeutic durability. The integration of molecular profiling with advanced computational approaches, including artificial intelligence and biomimetic models, holds significant promise for the future development of personalized resistance-mitigating interventions, though a detailed exploration is beyond the current scope. Collectively, these strategies reflect a paradigm shift from conventional monotherapies toward multifaceted, precision-guided treatment approaches. This review aims to provide a comprehensive overview of current innovations and propose future directions for overcoming drug resistance in BC. Full article

Breast cancer is the leading threat to the health of women, with a rising global incidence linked to social and psychological factors. Among its subtypes, triple-negative breast cancer (TNBC), which lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, is highly heterogeneous with early metastasis and a poor prognosis, making it the most challenging subtype. Mounting evidence shows that the mitochondrial quality control (MQC) system is vital for maintaining cellular homeostasis. Dysfunction of the MQC is tied to tumor cell invasiveness, metastasis, and chemoresistance. This paper comprehensively reviews the molecular link between MQC and TNBC development. We focused on how abnormal MQC affects TNBC progression by influencing chemoresistance, immune evasion, metastasis, and cancer stemness. On the basis of current studies, new TNBC treatment strategies targeting key MQC nodes have been proposed. These findings increase the understanding of TNBC pathogenesis and offer a theoretical basis for overcoming treatment challenges, providing new research angles and intervention targets for effective precision therapy for TNBC. Full article

Triple-negative breast cancer (TNBC), characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), remains a therapeutic challenge due to its aggressive nature, limited treatment options, and high recurrence rates. Current therapies, including chemotherapy and immune checkpoint inhibitors, face resistance driven by tumor heterogeneity, immunosuppressive signaling, and dysregulated redox pathways. This review explores silibinin’s potential to modulate the tumor immune microenvironment (TIME) and overcome therapeutic resistance in TNBC. Silibinin exerts multifaceted anticancer effects by suppressing PD-L1 expression through the inhibition of JAK/STAT3 signaling and MUC1-C interaction, attenuating NF-κB-driven inflammation, and downregulating CCL2-mediated recruitment of tumor-associated macrophages (TAMs). Additionally, silibinin disrupts redox adaptation by targeting the Nrf2-EGFR-MYC-TXNIP axis, enhancing oxidative stress and chemosensitivity. Preclinical studies highlight its ability to inhibit epithelial–mesenchymal transition (EMT), reduce cancer stem cell (CSC) populations, and synergize with existing therapies like PD-1 inhibitors. Despite its low bioavailability, advanced formulations such as liposomes and nanoparticles show promise in improving delivery and efficacy. By reshaping TIME through dual antioxidant and immunomodulatory mechanisms, silibinin emerges as a viable adjunct therapy to reverse immunosuppression and chemoresistance in TNBC. Full article