Agata Sirek

Apoptosis maintains tissue homeostasis, and its dysregulation is closely associated with breast cancer progression and therapeutic resistance. We performed an integrative analysis of apoptosis-related signaling in breast cancer tissues across five molecular subtypes and compared these patterns with systemic apoptotic responses following cryoablation of benign fibroadenomas. Gene expression profiling was conducted using mRNA microarrays and validated by qRT-PCR and ELISA. Apoptosis pathway activity was assessed with the MSigDB HALLMARK_APOPTOSIS gene set, including intrinsic and extrinsic pathway scoring and an apoptotic balance index (ABI). MicroRNA profiling combined with in silico analyses identified potential miRNA–mRNA interactions. A progressive shift toward reduced pro-apoptotic and enhanced stress-adaptive signaling was observed with increasing tumor aggressiveness, most pronounced in triple-negative and non-luminal HER2-positive cancers. This pattern included reduced intrinsic pathway activity, decreased ABI, downregulation of pro-apoptotic genes (BIK, BMF, TXNIP), and upregulation of stress-associated or cytoprotective genes (HSPB1, PPT1). Several expression patterns were accompanied by overexpression of miRNAs (miR-582-5p, miR-421, miR-106b-5p, miR-20a-5p, miR-20b-5p, miR-93-5p) predicted to target apoptosis-related genes. In contrast, fibroadenoma cryoablation was associated with transient systemic modulation of apoptosis-related genes and proteins followed by gradual normalization. These findings highlight differences between apoptosis-related dysregulation in malignant tissue and regulated systemic responses following benign tissue injury, supporting pathway-level interpretation and identifying candidate molecular networks warranting further mechanistic and translational investigation.

Nuclear factor kappa B (NF-κB) signaling plays a central role in inflammation, immunity, cell survival, and cancer progression. Its constitutive activation is frequently observed in breast cancer, contributing to tumor growth, treatment resistance, and metastasis. MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression and may modulate NF-κB signaling in a subtype-specific or -independent manner. The aim of the study was to identify miRNAs that may potentially regulate the activity of genes associated with NF-κB signaling across five molecular subtypes of breast cancer in Polish women. Tumor and matched normal tissue samples were collected from 405 patients with five breast cancer subtypes: luminal A (n = 130), HER2-negative luminal B (n = 100), HER2-positive luminal B (n = 96), non-luminal HER2-positive (n = 36), and triple-negative breast cancer (TNBC, n = 43). Expression profile of selected NF-κB-related genes were evaluated using mRNA microarrays and RT-qPCR. Protein levels were assessed by ELISA. Candidate regulatory miRNAs were identified via miRNA microarrays and validated using the miRDB database. A consistent upregulation of MAP3K7, TAB2, TNFAIP3, CSNK2A1, BCL2L1, XIAP, CXCL2, and PLAU was observed across all subtypes, suggesting activation of canonical NF-κB signaling. Downregulation of specific miRNAs, miR-1297 and miR-30a (targeting MAP3K7), miR-134 (TAB2), miR-125b (TNFAIP3), and miR-4329 (XIAP), may contribute to this deregulation. For CSNK2A1, BCL2L1, CXCL2, and PLAU, no regulatory miRNAs meeting our criteria were identified. Our study reveals a subtype-independent activation of the canonical NF-κB signaling pathway in breast cancer, underpinned by consistent upregulation of key components (at both the transcript and protein levels. Dysregulation of specific miRNAs likely contributes to this altered gene expression. These findings suggest the presence of a common NF-κB-driven oncogenic program across molecular subtypes, with potential implications for developing miRNA-based therapeutic strategies targeting inflammation, survival signaling, and treatment resistance in breast cancer.

Ferroptosis is an iron-dependent form of regulated cell death driven by lipid peroxidation and oxidative stress, increasingly implicated in cancer biology. However, its molecular regulation across breast cancer subtypes and its potential systemic manifestations remain incompletely understood. The aim of this study was to identify ferroptosis-associated molecular alterations that are largely shared across subtypes and to evaluate their systemic reflection following localized tissue injury. Tumor and matched normal breast tissues representing major molecular subtypes were analyzed. Global mRNA and miRNA expression profiling was performed using microarrays, followed by validation of selected genes using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Functional enrichment and protein–protein interaction analyses were conducted to characterize associated pathways. In addition, systemic responses were assessed in patients undergoing fibroadenoma cryoablation through longitudinal blood sampling. Six ferroptosis-related genes (SLC7A11, GPX4, FTH1, NQO1, NFE2L2, SQSTM1) demonstrated consistent upregulation across all breast cancer subtypes, with higher expression observed in more aggressive tumors. These genes are functionally linked to antioxidant defense, iron metabolism, and oxidative stress regulation, and their coordinated expression pattern is consistent with activation of NRF2-dependent cytoprotective pathways. Downregulation of selected miRNAs may contribute to this expression profile but likely represents a secondary regulatory mechanism. Survival analysis revealed heterogeneous and subtype-dependent associations, with limited and gene-specific prognostic relevance. Cryoablation induced transient increases in circulating levels of the analyzed proteins, reflecting systemic responses to localized tissue injury. In conclusion, breast cancer is characterized by a largely shared ferroptosis-associated molecular signature across subtypes; however, its clinical impact appears to be variable and context-dependent. Systemic detection of related molecular signals suggests potential utility as indicators of tissue stress responses, although their role as specific biomarkers of ferroptosis requires further validation.

Background/Objectives: The Notch signaling pathway regulates cell fate, proliferation, and differentiation, and its dysregulation has been implicated in various cancers, including breast cancer. MicroRNAs (miRNAs) are critical post-transcriptional regulators that can modulate Notch pathway components. The aim of this study was to identify miRNAs that may potentially regulate the expression of Notch pathway-related genes across five molecular subtypes of breast cancer in Polish women. Methods: Tumor and adjacent normal tissue samples were collected from 405 patients with five breast cancer subtypes: luminal A (n = 130), HER2-negative luminal B (n = 100), HER2-positive luminal B (n = 96), non-luminal HER2-positive (n = 36), and triple-negative breast cancer (n = 43). Gene expression was profiled using mRNA microarrays and validated with RT-qPCR and ELISA. Candidate regulatory miRNAs were identified by miRNA microarrays and confirmed using the miRDB database. Results: APH1A, CTBP1, DTX1, HEY1, HEY2, JAG2, NOTCH4, TLE2, and TLE4 were consistently dysregulated across all breast cancer subtypes. Overexpression of HEY1 and JAG2 may be driven by decreased levels of miR-145, miR-98, and miR-381. Conversely, downregulation of TLE4 may be associated with elevated expression of miR-196a and miR-155. No regulatory miRNAs meeting the selection criteria were identified for APH1A, CTBP1, DTX1, HEY2, NOTCH4, or TLE2. Conclusions: The consistent alterations suggest the presence of a shared Notch-driven oncogenic signature in breast cancer, potentially driving cell proliferation, stemness, and resistance to therapy. These findings enhance our understanding of Notch signaling in breast cancer and propose novel miRNA–Notch interactions as candidate targets for therapeutic intervention.

Breast cancer (BC) comprises heterogeneous subtypes with distinct molecular drivers and clinical behaviors. Among the key signaling pathways implicated in BC progression is the mitogen-activated protein kinase (MAPK) cascade, which regulates cell proliferation, apoptosis, and stress responses. microRNAs (miRNAs), as post-transcriptional regulators, are increasingly recognized as modulators of MAPK-associated genes, yet their integrated role across BC subtypes remains incompletely understood. This study included 405 patients with histopathologically confirmed BC, stratified into luminal A (LumA), HER2-negative luminal B, HER2-positive luminal B, non-luminal HER2-positive, and triple-negative breast cancer (TNBC). Control tissues were obtained from matched surgical margins. We performed mRNA profiling (Affymetrix microarrays), reverse transcription-quantitative polymerase chain reaction (RT-qPCR), protein quantification (enzyme-linked immunosorbent assay (ELISA), and miRNA expression analysis. Predicted miRNA-mRNA interactions were analyzed using the miRDB database. Functional protein–protein interactions were explored using the STRING database. MAP3K1, MAP2K4, and TP53 were significantly downregulated across all subtypes, while PPM1D, LMTK3, and TGFB1 were upregulated, especially in TNBC. These alterations were supported by concordant changes at the protein level. Dysregulated miRNAs—miR-21-3p, miR-23c, miR-27a-3p, miR-205-3p, and miR-300—exhibited in-verse expression patterns relative to their predicted target genes. STRING analysis identified TP53 as a central hub, linking MAPK signaling with stress and apoptotic pathways. This integrated transcriptomic and miRNA profiling study reveals subtype-specific dysregulation of MAPK-associated genes and their miRNA regulators in BC, with TNBC exhibiting the most profound alterations. These findings provide insight into potential targets for personalized therapeutic strategies.

Purpose Biogenic amines (BAs) are known to influence tumorigenesis, yet their precise role in breast cancer remains unclear. This study aimed to investigate the expression patterns of BA-related genes, proteins, and their regulatory miRNAs across different breast cancer subtypes to identify potential biomarkers and therapeutic targets. Methods A cohort of 501 breast cancer patients was classified into luminal A (n = 130), luminal B HER2− (n = 100), luminal B HER2+ (n = 96), non-luminal HER2+ (n = 36), and triple-negative breast cancer (TNBC; n = 43). Gene expression was assessed via microarray analysis and validated using RT-qPCR. Protein levels were quantified using ELISA, while miRNA profiling was conducted to identify post-transcriptional regulatory interactions. Statistical significance was determined using ANOVA and Tukey’s post-hoc test (p < 0.05). Results Histamine-related genes (HRH1-HRH4) were upregulated across all subtypes, with HRH2 and HRH4 most elevated in TNBC (FC = 7.18, p < 0.01). DRD2 showed widespread upregulation (FC = 15.98, p < 0.001), whereas DRD5 was markedly downregulated, especially in non-luminal HER2+ tumors (FC = − 13.01, p < 0.01). miRNA analysis revealed downregulation of hsa-miR-30b-3p and hsa-miR-372-5p in TNBC and HER2+ subtypes, correlating with HRH2 and HRH4 overexpression (p < 0.05). EGR1 and ICAM1 exhibited strong subtype-specific expression, with ICAM1 significantly upregulated in TNBC (FC = 25.76, p < 0.001). Conclusion Subtype-specific dysregulation of BA-related genes and miRNAs suggests their involvement in tumor progression, immune modulation, and metabolic regulation. The findings highlight potential therapeutic targets, particularly in TNBC and HER2+ subtypes.