Similar Datasets
Project description:Aging is a major risk factor for breast cancer, yet how it shapes tumor development, molecular phenotype, and immune evasion remains incompletely understood. Deciphering how aging influences cancer development is critical for improving risk assessment, prevention, and treatment. Here, using a N-nitroso-N-methylurea (NMU)-induced rat mammary tumor model that recapitulates key features of human breast cancer, we integrated bulk and single-cell transcriptomics, whole-exome sequencing, and histopathological analysis to dissect age-associated differences in tumorigenesis. We found that age at NMU exposure critically influences tumor incidence, mutational burden, subtype, and immune microenvironment. Tumors arising in aged rats originate from luminal progenitor-like cells with increased genomic instability, suppressed immune infiltration, and impaired antigen presentation linked to loss of heterozygosity at Chr 20p. These age-associated epithelial and immune changes were conserved in human breast cancers, where loss of the homologous Chr 6p region correlated with reduced lymphocyte infiltration and shorter relapse-free survival. These findings reveal that aging alters the tumor-initiating cell population and promotes immune-evasive tumor states through chromosomal instability-driven antigen presentation defects. Our work provides mechanistic insight into the reduced efficacy of immunotherapy in older patients.
2026-01-11 | GSE297544 | GEO
Project description:Aging is a major risk factor for breast cancer, yet how it shapes tumor development, molecular phenotype, and immune evasion remains incompletely understood. Deciphering how aging influences cancer development is critical for improving risk assessment, prevention, and treatment. Here, using a N-nitroso-N-methylurea (NMU)-induced rat mammary tumor model that recapitulates key features of human breast cancer, we integrated bulk and single-cell transcriptomics, whole-exome sequencing, and histopathological analysis to dissect age-associated differences in tumorigenesis. We found that age at NMU exposure critically influences tumor incidence, mutational burden, subtype, and immune microenvironment. Tumors arising in aged rats originate from luminal progenitor-like cells with increased genomic instability, suppressed immune infiltration, and impaired antigen presentation linked to loss of heterozygosity at Chr 20p. These age-associated epithelial and immune changes were conserved in human breast cancers, where loss of the homologous Chr 6p region correlated with reduced lymphocyte infiltration and shorter relapse-free survival. These findings reveal that aging alters the tumor-initiating cell population and promotes immune-evasive tumor states through chromosomal instability-driven antigen presentation defects. Our work provides mechanistic insight into the reduced efficacy of immunotherapy in older patients.
2026-01-11 | GSE297548 | GEO
Project description:Aging is a major risk factor for breast cancer, yet how it shapes tumor development, molecular phenotype, and immune evasion remains incompletely understood. Deciphering how aging influences cancer development is critical for improving risk assessment, prevention, and treatment. Here, using a N-nitroso-N-methylurea (NMU)-induced rat mammary tumor model that recapitulates key features of human breast cancer, we integrated bulk and single-cell transcriptomics, whole-exome sequencing, and histopathological analysis to dissect age-associated differences in tumorigenesis. We found that age at NMU exposure critically influences tumor incidence, mutational burden, subtype, and immune microenvironment. Tumors arising in aged rats originate from luminal progenitor-like cells with increased genomic instability, suppressed immune infiltration, and impaired antigen presentation linked to loss of heterozygosity at Chr 20p. These age-associated epithelial and immune changes were conserved in human breast cancers, where loss of the homologous Chr 6p region correlated with reduced lymphocyte infiltration and shorter relapse-free survival. These findings reveal that aging alters the tumor-initiating cell population and promotes immune-evasive tumor states through chromosomal instability-driven antigen presentation defects. Our work provides mechanistic insight into the reduced efficacy of immunotherapy in older patients.
2026-01-11 | GSE297627 | GEO
Project description:Aging-associated differences in mammary tumor-initiating populations and immune evasion pathways in breast cancer
| PRJNA1265468 | ENA
Project description:Aging-associated differences in mammary tumor-initiating populations and immune evasion pathways in breast cancer [bulk_RNA_seq]
| PRJNA1265173 | ENA
Project description:Aging-associated differences in mammary tumor-initiating populations and immune evasion pathways in breast cancer [scRNA-Seq]
| PRJNA1265495 | ENA
Project description:IntroductionA subpopulation of cancer cells, tumor-initiating cells, is believed to be the driving force behind tumorigenesis and resistance to radiation and chemotherapy. The persistence of tumor-initiating cells may depend on altered regulation of DNA damage and checkpoint proteins, as well as a reduced propensity to undergo apoptosis or senescence.MethodsTo test this hypothesis, we isolated CD24-/low/CD44+ tumor-initiating cells (as mammospheres) from MCF-7 breast cancer cells grown in adherent monolayer culture, and carried out a comprehensive comparison of cell death and DNA damage response pathways prior to and after exposure to ionizing radiation in mammospheres and monolayer MCF-7 cells. Single and double-strand break repair was measured by single-cell gel electrophoresis. The latter was also examined by phosphorylation of histone H2AX and formation of 53BP1 and Rad51 foci. Apoptosis was quantified by flow-cytometric analysis of annexin V-binding and senescence was analyzed on the basis of cellular beta-galactosidase activity. We employed the telomeric repeat amplification protocol to quantify telomerase activity. Expression of key DNA repair and cell cycle regulatory proteins was detected and quantified by western blot analysis.ResultsOur data demonstrate that in comparison to the bulk population of MCF-7 cells (predominantly CD24+/CD44+), the MCF-7 mammosphere cells benefit from a multifaceted approach to cellular protection relative to that seen in monolayer cells, including a reduced level of reactive oxygen species, a more active DNA single-strand break repair (SSBR) pathway, possibly due to a higher level of expression of the key SSBR protein, human AP endonuclease 1 (Ape1), and a significantly reduced propensity to undergo senescence as a result of increased telomerase activity and a low level of p21 protein expression. No significant difference was seen in the rates of double-strand break repair (DSBR) between the two cell types, but DSBR in mammospheres appears to by-pass the need for H2AX phosphorylation.ConclusionsEnhanced survival of MCF-7 tumor-initiating cells in response to ionizing radiation is primarily dependent on an inherent down-regulation of the senescence pathway. Since MCF-7 cells are representative of cancer cells that do not readily undergo apoptosis, consideration of senescence pathways may play a role in targeting stem cells from such tumors.
| S-EPMC2917024 | biostudies-literature
Project description:Breast cancer is a significant cause of morbidity and mortality in women, with over two million new cases reported worldwide each year, the majority of which occur in post-menopausal women. Despite advances in early detection and treatment, approximately one-third of patients diagnosed with breast cancer will develop metastatic disease. The pathogenesis and progression of breast cancer are influenced by a variety of biological and social risk factors, including age, ethnicity, pregnancy status, diet, and genomic alterations. Recent advancements in breast cancer research have focused on harnessing the power of the patient's adaptive and innate immune systems for diagnostic and therapeutic purposes. The breast immune microenvironment plays a critical role in regulating tissue homeostasis and resistance to tumorigenesis. In this review, we explore the dynamic changes in the breast immune microenvironment that occur with age, how these changes impact breast cancer development and progression, and how targeted therapeutic interventions that leverage the immune system can be used to improve patient outcomes. Our review emphasizes the importance of understanding the complex interplay between aging, the immune system, and breast cancer, and highlights the potential of immune-based therapies in the fight against this devastating disease.
| S-EPMC10046531 | biostudies-literature
Project description:Tumors derived from rat LA7 cancer stem cells (CSCs) contain a hierarchy of cells with different capacities to generate self-renewing spheres and tubules serially ex vivo and to evoke tumors in vivo. We isolated two morphologically distinct cell types with distinct tumorigenic potential from LA7-evoked tumors: cells with polygonal morphology that are characterized by expression of p21/(WAF1) and p63 and display hallmarks of CSCs and elongated epithelial cells, which generate tumors with far less heterogeneity than LA7 CSCs. Serial transplantation of elongated epithelial cells results in progressive loss of tumorigenic potential; tumor heterogeneity; CD44, E-cadherin, and epithelial cytokeratin expression and increased alpha-smooth muscle actin I and vimentin expression. In contrast, serial transplantation of LA7 CSCs can be performed indefinitely and results in tumors that maintain their heterogeneity, consistent with self-renewal and multilineage differentiation potential. Collectively, our data show that polygonal cells are CSCs, whereas epithelial elongated cells are lineage-committed progenitors with tumorigenic potential, and suggest that tumor progenitors, although lacking indefinite self-renewal potential, nevertheless may make a substantial contribution to tumor development. Because LA7 cells can switch between conditions that favor maintenance of pure CSCs vs. differentiation into other tumor cell types, this cell system provides the opportunity to study factors that influence CSC self-renewal and differentiation. One factor, p63, was identified as a key gene regulating the transition between CSCs and early progenitor cells.
| S-EPMC2575224 | biostudies-literature
Project description:Nucleostemin (NS) is highly expressed in normal stem cells and tumors and is upregulated by estradiol in MCF7 breast cancer cells. To investigate the role of NS in mammary tumorigenesis, we established first that NS is expressed at higher levels in the basal cell type than in the luminal cell type in mouse mammary tumors and human breast cancer cells. NS expression was also increased during progression of mammary tumors in MMTV-Wnt1 and MMTV-PyMT transgenic mice and by the tumor sphere culture. To determine the function of NS-enriched tumor cells, we generated a bacterial artificial chromosome transgenic mouse line expressing green fluorescent protein (GFP) from the NS promoter and bred it to MMTV-Wnt1 mice, so that NS-expressing cells can be prospectively isolated based on their GFP levels. Notably, NS-enriched mammary tumor cells exhibited stronger in vitro and in vivo tumorigenic activities and expressed higher levels of K5, CD133, Oct4, telomerase reverse transcriptase, and C-X-C chemokine ligand 12 compared with NS-deficient mammary tumor cells. Furthermore, knockdown of NS dramatically reduced the sphere-forming activity of MDA-MB-231 and MCF7 human breast cancer cells. Our findings establish the tumor-initiating and molecular features of NS-enriched mammary tumor cells, suggesting that NS may offer a valuable therapeutic target.
| S-EPMC2982898 | biostudies-literature