Search Results (342)

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. Full article

Erythroid acute myeloid leukemia (AML) cell line OCI-M2 expresses a particular oncogenic network: IRF6, in concert with ETV2 and HEY1, aberrantly activates NKL homeobox gene NKX2-4, which in turn represses megakaryocytic lineage factor FLI1. Interestingly, in keratinocytes, IRF6 is able to bind glucose which promotes IRF6-dimerization and thus alters its binding site selection. Here, we used OCI-M2 as a model to investigate the role of glucose level and IRF6 in leukemogenesis. Treatment of OCI-M2 with high glucose or 2-deoxy-glucose resulted in the downregulation of IRF6 and NKX2-4, and the upregulation of FLI1, indicating that glucose-mediated dimerization of IRF6 altered its reported autoactivation. The screening of this cell line for genes encoding glycolytic enzymes identified aberrant overexpression of glucose-6-phosphate isomerase (GPI) and phosphofructokinase L (PFKL), which were targeted by genomic amplification and chromothripsis-like alterations, respectively. Furthermore, GPI was activated by NKX2-4 and ETV2, and PFKL by ETV2. Finally, siRNA-mediated downregulation of PFKL resulted in elevated glucose levels, suppressed expression of IRF6 and NKX2-4, and activated FLI1. Thus, we connected an oncogenic regulatory network with deregulated glycolytic enzymes and glucose metabolism, thereby establishing a new in vitro model to develop novel therapeutic avenues in AML subsets. Full article

Background/Objectives: The oncoprotein EWS::FLI1 is a chimeric transcription factor that aberrantly brings transcriptional deregulation relevant to Ewing sarcoma. It is also regarded as a therapeutic target for suppressing oncogenic progression, but the inhibition and clearance of the EWS::FLI1 oncoprotein remain a challenge. Methods: We apply a polyglutamine (polyQ) fusion strategy to directly target EWS::FLI1 in suppression of its transcriptional malfunction in A673 cells derived from Ewing sarcoma. Based on the template of the N-terminal fragment of polyQ-expanded ataxin-7 (Atx7_93Q-N172) and the homologous peptides of EWS::FLI1, we have designed and constructed three polyQ fusion proteins, namely Atx7_93Q-N172-SYGQ1, Atx7_93Q-N172-SYGQ2, and Atx7_93Q-N172-LCD. Results: Supernatant/pellet fractionation and immunofluorescence imaging reveal that the polyQ fusion proteins co-precipitate and co-localize with EWS::FLI1 in A673 cells, indicating that the polyQ fusions we have designed can sequester endogenous EWS::FLI1 into insoluble aggregates and reduce its cellular availability. Moreover, these polyQ fusions, especially Atx7_93Q-N172-LCD, alter the expression of EWS::FLI1 downstream genes, with an increase in P21 (CDKN1A) and a decrease in c-Myc. Conclusions: These results demonstrate that the engineered polyQ fusions entrap endogenous EWS::FLI1 protein into aggregates and reduce its soluble fraction in Ewing sarcoma cells. This study provides an alternative potential for treating Ewing sarcoma and other tumors by directly targeting the oncogenic proteins in the future. Full article

Colitis-associated colorectal cancer (CAC) represents a distinct subtype of colorectal malignancy that arises in the setting of chronic inflammatory bowel disease (IBD). Unlike sporadic colorectal cancer, CAC develops through inflammation-driven molecular pathways, in which epigenetic alterations play a pivotal role in tumor initiation and progression. This review highlights the major epigenetic mechanisms implicated in CAC, including DNA methylation, histone modifications, and microRNA (miRNA) dysregulation. Aberrant DNA methylation patterns, such as promoter hypermethylation of tumor suppressor genes and global hypomethylation, contribute to genomic instability and altered gene expression. In parallel, inflammation-induced changes in histone configuration modulate chromatin accessibility and transcriptional activity of key oncogenic and tumor-suppressive pathways. Furthermore, deregulated miRNAs influence multiple aspects of CAC pathogenesis by targeting genes involved in inflammation and tumor progression. Understanding these epigenetic processes provides valuable insights into the development of colorectal malignancy and identifies potential biomarkers for early detection and intervention in colitis-associated colorectal cancer. Full article

Hepatoblastoma (HB), the most common pediatric liver malignancy, tends to be highly curable although advanced or recurrent disease has less favorable outcomes. Because patients are invariably <3–4 years of age, chemotherapies can cause significant long-term morbidities. Immortalized HB cell lines could be of great utility for drug screening, for the identification of novel therapeutic susceptibilities, and for studies requiring highly regulated and/or rapidly changing in vitro environments. However, HB research is hampered by a paucity of these lines that could be used for such purposes, with only two human cell lines being readily available, neither of which represents the most common HB molecular subtypes. Recently, immortalized cell lines have been derived from murine HBs that are driven by the most common oncogenes and tumor suppressors associated with human tumors. These comprise five distinct groups associated with the deregulation of each of the four possible combinations of oncogenic forms of the β-catenin, YAP and NRF2 transcription factors or the over-expression of MYC. All five groups share many of the attributes and molecular signatures of actual human HBs. In addition, they have been used for purposes as diverse as identifying novel molecular targets through the use of Crispr-based screens and the demonstration that some HB cells can trans-differentiate into endothelial cells that facilitate tumor growth. The experience gained from these models and advances in the propagation of human hepatocytes in mice suggests that it may soon be possible to generate bespoke human immortalized human cell lines. Full article

The transcription factor E2F is the principal target of the tumor suppressor pRB. In almost all cancers, pRB function is disabled due to oncogenic changes, leading to enhanced E2F activity, thereby facilitating aberrant cell proliferation. Enhanced E2F activity has been utilized to drive gene expression preferentially in cancer cells using E2F target promoters, such as the E2F1 promoter. However, these promoters are also activated by physiological E2F activity in normal proliferating cells, resulting in gene expression in normal proliferating cells. In contrast, promoters of tumor suppressor genes, such ARF and TAp73, are activated by deregulated E2F activity, induced by loss of pRB control, but not by physiological E2F activity, induced by growth stimulation, thereby providing a mechanism to drive expression specifically in cancer cells. Here we show artificial promoters, in which E2F-responsive elements of the TAp73 gene are tandemly connected to the ARF core promoter, exhibited higher cancer cell specificity than E2F1, hTERT, or ARF promoters. Moreover, adenoviruses driving a cytotoxic gene using these artificial promoters showed cancer cell-specific cytotoxicity and inhibited tumor growth in a xenograft mouse model. These results indicate utility of tumor suppressor gene promoter elements to drive gene expression specifically in cancer cells. Full article

MicroRNAs (miRNAs) are key regulators of gene expression with critical roles in oncogenic signaling. Endometrial cancer (EC) has been redefined with the identification of POLE-ultramutated tumors which, despite their hypermutated phenotype, show more favorable prognosis. We profiled miRNA expression in tumor tissues from forty (40) EC patients and twenty (20) healthy controls using qPCR panels. POLE exonuclease domain mutations (P286R, V411L) were genotyped, and subgroup analyses were conducted between POLE-mutated (n = 7) and POLE-wild-type (n = 33) tumors. Bioinformatic analyses included validated miRNA–mRNA interactions, target enrichment, and Gene Ontology (GO) pathway mapping. Comparison of EC versus healthy endometrium revealed 50 significantly dysregulated (∣log₂ (FoldReg)∣ > 1 and BH FDR < 0.05) miRNAs, including up-regulation of the oncogenic hsa-miR-181a-5p, hsa-miR-23a-3p, hsa-miR-200c-3p, and down-regulation of tumor-suppressive let-7 family members. Target enrichment implicated canonical oncogenic regulators such as MYC, TP53, and VEGFA. POLE-mutated tumor analysis demonstrated a miRNA signature, with 19 miRNAs significantly down-regulated, including let-7f-5p and hsa-miR-200b-3p. Findings for the EC versus healthy endometrium comparison were validated against TCGA-UCEC sequencing data which confirmed concordant dysregulation of key miRNAs across platforms. Our findings reveal that EC is characterized by widespread miRNA deregulation, with a unique global down-regulation signature in POLE-mutated tumors. These results highlight the potential of miRNAs as complementary biomarkers for classification and potential targets in EC. Full article

The Hedgehog (HH) signaling pathway is an evolutionarily conserved, multi-component signaling pathway. Its activation is initiated by the Hh protein, which signals upstream regulators PATCH and SMO to activate the transcription factor GLI. Upon activation, GLI translocates to the nucleus to induce the transcription of Hh/GLI target genes. Under normal conditions, the HH pathway plays a crucial role in embryogenesis, development, tissue patterning, and stem cell maintenance. Deregulation of the HH signaling pathway leads to various diseases, including cancer. However, in many human cancers, GLI1 is upregulated through a non-canonical pathway (independent of the HH pathway). This aberrant regulation of GLI1 via a non-canonical pathway is linked to the increased expression of various oncogenes. Aberrant expression of GLI not only affects the genes of several DNA repair pathways but also cancer stem cell pathways, which can contribute to genome instability and ultimately lead to cancer. The ineffectiveness of current HH pathway inhibitors in clinical trials necessitates the discovery of new HH pathway inhibitors. In this review, we will discuss our current understanding of the aberrant signaling of the HH-GLI pathway and focus on GLI1-mediated HH signaling in cancers, cancer stem cells, and carcinogenesis. We will also discuss the effectiveness of current HH inhibitors/drugs and combination therapies based on recent advances in this field. Furthermore, we will also review the role of HH-GLI in cancer stem cell markers, DNA damage response, gene regulation, tumor initiation, metastasis, cancer pathogenesis, and the role of drugs/inhibitors on this pathway. Full article

G-quadruplexes have been identified as a promising anti-cancer target because of their ability to modulate the stability of mRNAs encoding oncogenes, tumor suppressor genes, and other potential therapeutic targets. Deregulation of DNA damage and Unfolded Protein Response pathways in cancer cells may create vulnerabilities that can be exploited therapeutically. Previous studies have shown variations in the relative expression of DDR and UPR components in canine lymphoma and leukemia cell lines CLBL-1, CLB70, and GL-1. In the present study, we report the presence of G-quadruplex structures in these canine cell lines. Downregulation of the expression of DDR and UPR components at the mRNA level was observed in the CLBL-1 and CLB70 cell lines after stabilization of G4 structures using the ligand PhenDC3. In contrast, in GL-1 cells, important components of the DDR pathway, such as PARP1, GADD45A, and PIK3CB were upregulated in response to PhenDC3 treatment. Downregulation of DDIT4 mRNA expression, which encodes an important UPR component, was detected in the CLBL-1 and GL-1 cell lines after PhenDC3 exposure. These results suggest that G4 structures can be used to manipulate the expression of potential targets to treat lymphoma in dogs. A substantial enrichment of DNA replication and pyrimidine metabolism pathways was found in the GL-1 cell line after G4 stabilization. This finding suggests that PhenDC3 may induce DNA replication stress in this cell line. Collectively, these results support the feasibility of employing canine cancer cells as a model system to investigate the role of G-quadruplex structures in cancer. Full article

Background/Objectives: Hepatoblastoma (HB), the most common pediatric liver cancer, often bears mutations in and/or otherwise deregulates the oncogenic transcription factors β-catenin (B), YAP (Y) and NRF2 (N). HB research is hampered by a paucity of established cell lines, particularly those possessing these molecular drivers. All combinations of B, Y and N (BY, BN, YN and BYN) are tumorigenic when overexpressed in murine livers, but it has not been possible to establish cell lines from primary tumors. Recently, we found that concurrent, in vivo Crispr-mediated targeting of the Cdkn2a tumor suppressor locus allows for immortalized cell lines to be efficiently generated. Methods: We derived and characterized five immortalized cell lines from Cdkn2a-targeted BN and YN HBs. Results: Four of the above five cell lines retained their ability to grow as subcutaneous or “pseudo-metastatic” pulmonary tumors in the immunocompetent mice from which they originated. Most notably, when maintained under hypoxic conditions for as little as 2 days, BN cells transiently upregulated the expression of numerous endothelial cell (EC)-specific genes and acquired EC-like properties that benefited tumor growth. These lines and those from previously derived BY and BYN HBs also possessed similar sensitivities to four commonly employed chemotherapeutic drugs. Conclusions: The above-described approach is currently the only means to generate HB cell lines with pre-selected and clinically relevant oncogenic drivers. Its generic nature should also allow bespoke HB cell lines with other oncogenic drivers to be readily produced. A collection of such cell lines will be useful for studying tumor cell-to-EC trans-differentiation, interactions with the immune environment and drug sensitivities. Full article

Cancer cells arise from the cumulative acquisition of genetic and epigenetic alterations that affect vital cellular functions. Genomic instability results from deficiencies in protective mechanisms, such as cell cycle checkpoints, DNA replication control, or DNA repair. Claspin integrates a group of crucial proteins that maintain genome integrity. It participates in key cellular events such as DNA damage checkpoint activation, DNA replication, replication stress responses, DNA repair, epigenetic memory, and apoptosis. Given its crucial functions, a role for Claspin in cancer is not a surprise. Indeed, there is a considerable body of evidence linking Claspin deregulation with cancer. For instance, over-expression of Claspin and Tim promoted the survival of cancer cells by enabling adaptation to oncogene-induced replication stress. In addition, Claspin gene (CLSPN) mutations that affect checkpoint regulation have been identified in cancer patients, suggesting that they may contribute to cancer development. Changes in Claspin expression levels may be used as a prognostic marker in several types of cancer. Finally, several therapy-resistance signaling pathways seem to converge onto Claspin’s stabilization, turning Claspin into an attractive target for chemo- and radio-sensitization. In this review, we will focus on the role of Claspin in cancer and ways in which Claspin can be exploited in cancer therapy. Full article

Background: DEAD/H box 5 (DDX5) serves as a transcriptional coactivator for several transcription factors including E2F1, the primary target of the tumor suppressor pRB. E2F1 physiologically activated by growth stimulation activates growth-related genes and promotes cell proliferation. In contrast, upon loss of pRB function due to oncogenic changes, E2F1 is activated out of restraint by pRB (deregulated E2F1) and stimulates tumor suppressor genes such as ARF, which activates the tumor suppressor p53, to suppress tumorigenesis. We have recently reported that DDX5 augments deregulated E2F1 activity to induce tumor suppressor gene expression and apoptosis. During the analyses, we noted that over-expression of E2F1 increased DDX5 expression, suggesting a feed forward loop in E2F1 activation through DDX5. Objective: We thus examined whether the DDX5 gene is a target of deregulated E2F1. Method: For this purpose, we performed promoter analysis and ChIP assay. Result: The DDX5 promoter did not possess typical E2F binding consensus but contained several GC repeats observed in deregulated E2F1 targets. Insertion of point mutations in these GC repeats decreased responsiveness to deregulated E2F1 induced by over-expression of E2F1, but scarcely affected responsiveness to growth stimulation. ChIP assays showed that deregulated E2F1 induced by over-expression of E2F1 or expression of E1a, which binds pRB and releases E2F1, bound to the DDX5 gene, while physiological E2F1 induced by growth stimulation did not. Conclusions: These results suggest that the DDX5 gene is a target of deregulated E2F1, generating a feed forward loop mediating tumor suppressive E2F1 activity. Full article

Ribosome biogenesis is a highly coordinated, multi-step process that assembles the ribosomal machinery responsible for translating mRNAs into proteins. It begins with the rate-limiting step of RNA polymerase I (Pol I) transcription of the 47S ribosomal RNA (rRNA) genes within a specialised nucleolar region in the nucleus, followed by rRNA processing, modification, and assembly with ribosomal proteins and the 5S rRNA produced by Pol III. The ribosomal subunits are then exported to the cytoplasm to form functional ribosomes. This process is tightly regulated by the PI3K/RAS/MYC oncogenic network, which is frequently deregulated in many cancers. As a result, ribosome synthesis, mRNA translation, and protein synthesis rates are increased. Growing evidence supports the notion that dysregulation of ribosome biogenesis and mRNA translation plays a pivotal role in the pathogenesis of cancer, positioning the ribosome as a promising therapeutic target. In this review, we summarise current understanding of dysregulated ribosome biogenesis and function in cancer, evaluate the clinical development of ribosome targeting therapies, and explore emerging targets for therapeutic intervention in this rapidly evolving field. Full article

Proto-oncogenes in the RAS superfamily play dual roles in maintaining cellular homeostasis, such as regulating growth signals and contributing to cancer development through proliferation and deregulation. Activating proto-oncogenes in vitro transforms cells, underscoring their centrality in gene regulation and cellular networks. Despite decades of research, poor outcomes in advanced cancers reveal gaps in understanding Ras-driven mechanisms or therapeutic strategies. This narrative review examines RAS genes and Ras proteins in both housekeeping functions, such as cell growth, apoptosis, and protein trafficking, as well as in tumorigenesis, integrating insights from human (HRAS, KRAS, NRAS), mouse (Hras, Kras, Nras), and Drosophila melanogaster (ras) models. While RAS mutations are tightly linked to human tumors, the interplay between their standard and oncogenic functions remains complex. Even within the same tissue, distinct cancer pathways—such as the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways—can drive varied disease courses, complicating treatment. Advanced-stage cancers add further challenges, including heterogeneity, protective microenvironments, drug resistance, and adaptive progression. This synthesis organizes current knowledge of RAS gene regulation and Ras protein function from genomic alterations and intracellular signaling to membrane dynamics and extracellular interactions, offering a layered perspective on the Ras pathway’s role in both housekeeping and tumorigenic contexts. Full article

Background/Objectives: Cancer research aims to understand the cellular and molecular mechanisms involved, in order to identify new therapeutic targets and provide patients with more effective therapies that generate fewer side undesirable and toxic effects. Previous studies have demonstrated the role of small nucleolar RNAs (snoRNAs) in many physiological and pathological cellular processes, including cancers. SnoRNAs are a group of non-coding RNAs involved in different post-transcriptional modifications of ribosomal RNAs. Recently, we identified a new snoRNA (jouvence), first in Drosophila, and thereafter, by homology, in humans. Methods: Here, we characterize the effect of the knockdown of jouvence by a sh-lentivirus on human primary patient-derived glioblastoma cells. Results: The sh-lentivirus anti-jouvence induces a significant decrease in cell proliferation and leads to cell death. EdU staining confirmed this decrease, while TUNEL also showed the presence of apoptotic cells. An RNA-Seq analysis revealed a decrease, in particular, in the level of BAALC, a gene known to potentiate the oncogenic ERK pathway and deregulating p21, leading to cell cycle blockage. Conclusions: Altogether, these results allow the hypothesis that the knockdown of jouvence could potentially be used as a new anti-cancer treatment (sno-Therapy), especially against glioblastoma and also, potentially, against acute myeloid leukemia (AML) due to the BAALC deregulation. Full article