Search Results (576)

Introduction: Breast cancer is a heterogeneous malignancy influenced by diverse molecular profiles. The L-type amino acid transporter 1 (LAT1), encoded by the SLC7A5 gene, plays a key role in tumor metabolism, growth, and angiogenesis. Through its role in amino acid transport and activation of the mTORC1 signaling pathway, LAT1 has emerged as a potential therapeutic target. Objective: To evaluate SLC7A5/LAT1 expression and its association with clinicopathological parameters and molecular subtypes of invasive carcinoma of no special type (NST) in a Pakistani cohort. Methods: Eighty-three patients who underwent mastectomy or modified radical mastectomy for histologically confirmed primary invasive carcinoma of no special type were included. Immunohistochemistry was used to assess SLC7A5/LAT1 expression. Associations with clinicopathological features and molecular groups were analyzed using the Chi-square test. Results: The mean age of SLC7A5-positive patients were 48.4 ± 10.8 years. Overall, 24.1% of patients demonstrated SLC7A5 positivity. Although SLC7A5 expression was more frequent in cases categorized as having moderate or poor prognosis based on the Nottingham Prognostic Index (NPI), this trend was not statistically significant. Similarly, no significant associations were observed between SLC7A5 expression and other clinicopathological or molecular variables. Conclusions:SLC7A5/LAT1 expression was identified in approximately one-quarter of invasive breast carcinoma cases. Its expression appeared more common in tumors with poorer NPI categories, but without statistically verified associations. These findings suggest that SLC7A5 may act independently of conventional clinicopathological parameters. Larger, longitudinal studies with survival follow-up are required to clarify its prognostic and therapeutic significance. Full article

Background and Objectives: Cancer cachexia is a debilitating metabolic syndrome highly prevalent in colorectal cancer (CRC), characterized by progressive skeletal muscle wasting. The myostatin–FOXO signaling pathway contributes to this process by activating the E3 ubiquitin ligases MuRF-1 and Atrogin-1. Exercise is a promising non-pharmacological strategy, but its effects on this pathway in CRC cachexia remain unclear. This review aimed to synthesize preclinical evidence on the impact of exercise on the myostatin–FOXO axis. Materials and Methods: A comprehensive search was performed in PubMed/MEDLINE, Scopus, Web of Science, and Science Direct from inception through August 2025. Eligible studies included murine CRC models (C26 or Apc^Min/+) exposed to aerobic, resistance, or combined exercise interventions, with outcomes assessing myostatin, FOXO, MuRF-1, or Atrogin-1. Study quality was appraised using the CAMARADES 10-item checklist. Results: eleven studies met the criteria, with quality scores ranging from 6 to 8. Aerobic exercise, particularly voluntary wheel running, most consistently reduced MuRF-1 expression and systemic inflammation, whereas resistance and eccentric training exerted stronger inhibitory effects on FOXO and Atrogin-1. Myostatin was directly measured in two studies, yielding inconsistent results. Resistance and eccentric training promoted anabolic signaling (e.g., mTORC1), whereas aerobic protocols improved oxidative capacity. Variability in exercise type, intensity, and duration contributed to heterogeneity across findings. Conclusions: Exercise attenuates skeletal muscle catabolism in CRC-induced cachexia, mainly through modulation of the myostatin–FOXO pathway and downstream ligases. However, limited direct data on myostatin and methodological heterogeneity underscore the need for standardized protocols and translational studies. This review provides the first focused synthesis of exercise-mediated regulation of this pathway in CRC cachexia. Full article

Cancer cells can sustain survival independently of exogenous growth factors. To investigate their adaptation to serum deprivation, we analyzed transcriptomic responses in two cancer cell lines. Transcriptome analysis revealed upregulation of mRNAs encoding cholesterol biosynthesis enzymes. This was a critical adaptive response, as a pharmacological inhibition of the pathway with statin triggered a robust apoptotic cell death accompanied by generation of a mitochondrial reactive oxygen species. The mechanistic target of rapamycin complex 1 (mTORC1), a master regulator of cell growth, is known to be engaged in controlling lipid biosynthesis. We detected the high polysomal and preribosomal peaks not only in serum-containing medium but also under serum deprivation, indicating a high rate of protein synthesis and ribosomal biogenesis independent of serum. In addition, the inhibition of mTOR kinase activity substantially reduced polysome abundance, with a more pronounced effect in serum-deprived cancer cells. Notably, the mTOR kinase inhibition also prevented the upregulation of the cholesterol synthesis enzyme that established a direct link between mTOR activity, protein synthesis, and cholesterol biosynthesis. Together, our results show that cancer cells adapt to serum withdrawal by activating the cholesterol synthesis pathway through mTOR-dependent regulation of gene expression and protein synthesis, underscoring a critical mechanism of survival under serum withdrawal. Full article

Glucocorticoid therapy, using agents like dexamethasone (Dexa), often leads to muscle atrophy by increasing protein degradation via the ubiquitin–proteasome system while suppressing protein synthesis. Stigmasterol, a phytosterol with known bioactivities, has an unexplored role in muscle atrophy. This study investigated stigmasterol’s protective effects against Dexa-induced muscle atrophy and its impact on the FoxO3 and mTORC1 signaling pathways. Differentiated C2C12 myotubes were treated with Dexa (50 µM) ± stigmasterol (10 µM), and the morphology, viability, and protein levels in the FoxO3/MuRF1/MAFbx catabolic and mTOR/p70S6K/4E-BP1 anabolic signaling pathways were assessed. C57BL/6 mice received Dexa (20 mg/kg/day i.p.) ± stigmasterol (3 mg/kg/day oral) for 21 days, and the body/muscle mass, bone mineral density (BMD), fiber cross-sectional area (CSA), and muscle protein expression were measured. Stigmasterol (10 µM) was non-toxic and attenuated Dexa-induced reductions in myotube diameter and fusion in vitro, concurrent with suppressing Dexa-induced upregulation of FoxO3/MuRF1/MAFbx proteins and preventing the Dexa-induced dephosphorylation of mTOR/p70S6K/4E-BP1 proteins. In vivo, stigmasterol mitigated Dexa-induced losses in body weight, muscle mass, BMD, and fiber CSA. This protection was associated with attenuated upregulation of FoxO3 and MAFbx proteins in muscle tissue. Stigmasterol protected against Dexa-induced muscle atrophy in vitro and in vivo via modulation of the FoxO3–MAFbx catabolic pathway. These findings suggest stigmasterol inhibits excessive glucocorticoid-induced muscle protein breakdown. It therefore warrants further investigation as a potential therapeutic agent for glucocorticoid myopathy. Full article

Deep-sea mussels of the genus Bathymodiolus exhibit adaptability to nutrient-poor deep-sea environments by establishing nutritional intracellular symbiosis with chemosynthetic bacteria harbored within the gill epithelial cells. However, this poses a conflict for the innate immune system of the host, which must balance the tolerance of beneficial symbiotic bacteria with the need to eliminate exogenous microbes. This review synthesizes existing knowledge and recent findings on Bathymodiolus japonicus to outline the cellular and molecular mechanisms governing this symbiotic relationship. In the host immune system, hemocytes are responsible for systemic defense, whereas gill cells are involved in local symbiotic acceptance. Central to the establishment of symbiosis is the host’s phagocytic system, which non-selectively engulfs bacteria but selectively retains symbionts. We highlight a series of cellular events in gill cells involving the engulfment, selection, retention and/or digestion of symbionts, and the regulatory mechanism of phagocytosis through mechanistic target of rapamycin complex 1, which connects bacterial nutrient supply with host immune and metabolic responses. This integrated model of symbiosis regulation, which links immunity, metabolism, and symbiosis, provides a fundamental framework for understanding how hosts establish and maintain a stable coexistence with microbes, offering a new perspective on symbiotic strategies in diverse organisms. Full article

Sarcopenia, characterized by progressive skeletal muscle mass, strength, and functional loss, imposes a substantial global health burden. Irisin, a myokine derived from fibronectin type III domain-containing protein 5 (FNDC5), is critical for muscle health. Here, we investigate its role in mitigating glucocorticoid-induced sarcopenia using a mouse and C2C12 myotubes model. We quantified FNDC5/irisin levels in skeletal muscle and plasma and assessed muscle function (body weight, grip strength, wire-hanging, and locomotor activity), histology, and mitochondrial features following irisin administration to dexamethasone-treated mice. Western blot analyzed synthesis/hydrolysis regulators, apoptosis markers, and mitochondrial regulators in mouse muscle tissues and C2C12 myotubes. The results show that FNDC5/irisin was significantly downregulated in sarcopenic mice and atrophic C2C12 myotubes; exogenous irisin rescued muscle mass loss and functional impairment, improving body weight, muscle mass, grip strength, and mobility. Mechanistically, irisin bound SIRT1 with −12.7 kcal/mol affinity, activating a deacetylation cascade that suppressed FoxO3a transcriptional activity (attenuating proteasomal degradation) and enhanced mTORC1-mediated protein synthesis in C2C12 myotubes. Additionally, irisin potentiated PGC-1α signaling in mouse myocytes, promoting mitochondrial biogenesis and restoring contractile function in dystrophic fibers. Collectively, these findings demonstrate irisin alleviates glucocorticoid-induced muscle atrophy via SIRT1-dependent pathways, rebalancing muscle physiology and systemic energy homeostasis. This highlights irisin-based therapeutics as a promising exercise surrogate for sarcopenia management, offering novel clinical avenues. Full article

Background/Objectives: The mTOR serine/threonine kinase coordinates protein translation, cell growth, and metabolism, and its dysregulation promotes tumorigenesis. We present a reproducible, pan-cancer, network-aware framework that integrates curated resources with genomics to move beyond pathway curation, yielding falsifiable hypotheses and prioritized candidates for mTOR axis biomarker validation. Materials and Methods: We assembled MTOR-related genes and interactions from GeneCards, KEGG, STRING, UniProt, and PathCards and harmonized identifiers. We formulated a concise working model linking genotype → pathway architecture (mTORC1/2) → expression-level rewiring → phenotype. Three analyses operationalized this model: (i) pan-cancer alteration mapping to separate widely shared drivers from tumor-specific nodes; (ii) expression-based activity scoring to quantify translational/nutrient-sensing modules; and (iii) topology-aware network propagation (personalized PageRank/Random Walk with Restart on a high-confidence STRING graph) to nominate functionally proximal neighbors. Reproducibility was supported by degree-normalized diffusion, predefined statistical thresholds, and sensitivity analyses. Results: Gene ontology analysis demonstrated significant enrichment for mTOR-related processes (TOR/TORC1 signaling and cellular responses to amino acids). Database synthesis corroborated disease associations involving MTOR and its partners (e.g., TSC2, RICTOR, RPTOR, MLST8, AKT1 across selected carcinomas). Across cohorts, our framework distinguishes broadly shared upstream drivers (PTEN, PIK3CA) from lineage-enriched nodes (e.g., RICTOR-linked components) and prioritizes non-mutated, network-proximal candidates that align with mTOR activity signatures. Conclusions: This study delivers a transparent, pan-cancer framework that unifies curated biology, genomics, and network topology to produce testable predictions about the mTOR axis. By distinguishing shared drivers from tumor-specific nodes and elevating non-mutated, topology-inferred candidates, the approach refines biomarker discovery and suggests architecture-aware therapeutic strategies. The analysis is reproducible and extensible, supporting prospective validation of prioritized candidates and the design of correlative studies that align pathway activity with clinical response. Full article

Background/Objectives: Cardiovascular disease (CVD) is the leading cause of mortality in patients with rheumatoid arthritis (RA), not fully explained by traditional risk factors and disease activity alone. This study explored the relationship between circulating monocyte subsets, inflammatory cytokine profiles, and Mammalian Target of Rapamycin Complex (mTORC) signaling in RA patients with and without a history of CVD. Methods: Peripheral blood mononuclear cells from 9 RA patients with prior CVD, 9 carefully matched RA controls without CVD, and 6 healthy controls were analyzed by flow cytometry. Matching was rigorously conducted across clinically relevant variables, including age, sex, blood pressure, lipid profile, smoking status, RA duration, disease activity, Disease-Modifying Anti-Rheumatic Drug (DMARD) failures, and steroid use. Monocyte subsets were classified as inflammatory (CD14⁺HLA-DR⁺CCR2⁺) and non-inflammatory (CD14⁺CD163⁺CCR2⁻). Results: RA-CVD⁺ patients exhibited higher frequencies of inflammatory monocytes and elevated intracellular levels of Interleukin 1 β (IL-1β) and Interleukin 6 (IL-6) compared to RA-CVD⁻ patients and healthy controls. mTORC activation, assessed by phosphorylation of S6 Ribosomal Protein (S6Rp), was significantly increased in inflammatory monocytes from RA-CVD⁺ patients. Conclusions: S6Rp correlated with IL-1β and IL-6 levels only in the RA-CVD⁺ group, suggesting a link between mTORC activity and inflammatory monocyte function. Notably, these inflammatory features did not correlate with disease activity scores or disease duration. We observed increased mTORC1 signaling in inflammatory monocytes in RA-CVD⁺ patients, suggesting a potential association with cardiovascular comorbidity. Full article

Background: Doxorubicin (DOX) is a widely used chemotherapeutic agent, but its efficacy is often limited by cancer cell resistance. Although multiple DOX resistance mechanisms have been characterized, the global transcriptomic alterations underlying this phenomenon remain poorly understood. The aim of this work was to determine whether a common transcriptional response associated with DOX desensitization exists across tumor cells of different origins and to identify the core elements of this response. Methods: We performed an integrated bioinformatics analysis, including: analysis of independent transcriptomic datasets (comparing DOX-resistant neuroblastoma, breast, and cervical carcinoma cells to their DOX-sensitive counterparts), functional annotation of differentially expressed genes, reconstruction and topology analysis of gene networks, text mining, and survival analysis. The findings were validated through in vitro functional tests, RT-PCR, and analysis of the Cancer Therapeutics Response Portal and The Cancer Genome Atlas. Results: We showed that DOX resistance in cancer cells is associated with cytoskeletal reorganization, modulation of cell adhesion, cholesterol biosynthesis, and dysregulation of mTORC1, Wnt, and Gβγ signaling pathways. Network analysis identified a conserved regulome of 37 resistance-linked genes, with GJA1, SEH1L, TCF3, TUBA4A, and ZYX emerging as central hubs (mean degree: 8.7–19.7; mean fold change: 2.4–21.3). Experimental validation in DOX-resistant KB-8-5 cervical carcinoma cells and their sensitive counterparts (KB-3-1) confirmed enhanced cellular adhesion and reduced intracellular cholesterol levels associated with chemoresistance, supporting our in silico findings. A detailed follow-up analysis verified the upregulation of these hub genes in chemoresistant cells and their correlation with poor clinical outcomes across multiple cancer types. Conclusions: This integrative analysis identifies conserved transcriptomic signatures of DOX resistance and highlights hub genes GJA1, SEH1L, TCF3, TUBA4A, and ZYX with potential as predictive biomarkers and therapeutic targets. Targeting these pathways may help overcome chemoresistance and improve treatment outcomes in cancer patients. Full article

Glioblastoma multiforme (GBM) is an aggressive brain tumor with limited treatment options and a poor prognosis. Natural phytochemicals from Dendrobium species, particularly bibenzyl derivatives, possess diverse pharmacological activities, yet their potential against GBM remains largely unexplored. Here, we investigated the anticancer activity of 4,5,4′-trihydroxy-3,3′-dimethoxybibenzyl (TDB), a potent antioxidant bibenzyl derivative isolated from Dendrobium pachyglossum. In U87MG cells, TDB reduced viability in a dose- and time-dependent manner, suppressed clonogenic growth, induced apoptosis via Bax upregulation and Bcl-xL/Mcl-1 downregulation, and inhibited both mTORC1 and mTORC2 signaling. TDB also impaired cell migration and downregulated epithelial–mesenchymal transition (EMT)-associated proteins. Notably, TDB enhanced the cytotoxicity of temozolomide (TMZ), the current standard of care for GBM. These TMZ-sensitizing properties were further confirmed in patient-derived xenograft (PDX) Jx22 cells. To assess its potential for central nervous system delivery, blood–brain barrier (BBB) permeability was predicted using four independent in silico platforms—ADMETlab 3.0, LogBB_Pred, LightBBB, and BBB Predictor (Tree2C)—all of which consistently classified TDB as BBB-permeable. This predicted CNS accessibility, together with its potent anticancer profile, underscores TDB’s translational promise. Collectively, our findings identify TDB as a plant-derived antioxidant with multifaceted anti-GBM activity and favorable BBB penetration potential, warranting further in vivo validation and preclinical development as a novel therapeutic candidate for GBM. Full article

Background: Monocytes can commit to different phenotypes associated with specific features required in inflammation and homeostasis. Classical and alternative activation are two extremes of monocyte polarization and are both influenced by glucocorticoids (GCs). Methods: Human monocytes were sorted from the blood of healthy individuals and activated with LPS or IL-4 and IL-13, either in the absence or presence of dexamethasone (Dex). Metabolic adjustments were analyzed using Seahorse stress tests, SCENITH, and RT-qPCR. Results: LPS enhanced glycolysis and also, to a lesser extent, oxidative phosphorylation (OXPHOS), whereas addition of Dex induced a metabolic switch in favor of the latter. In contrast, activation of monocytes with IL-4 and IL-13 exclusively stimulated OXPHOS, which was suppressed by concomitant Dex treatment. The glycolytic function of monocytes matched alterations in gene expression of glucose transporters and metabolic enzymes, which were upregulated by LPS and inhibited by Dex via interference with the mTORC1 pathway but remained unaltered in response to IL-4 and IL-13. Although the dependency of classically and alternatively activated monocytes on OXPHOS and glucose usage markedly differed, modulation by GCs was limited to the latter polarization state. Conclusions: Our findings unravel a highly selective regulation of human monocyte energy metabolism by different activating stimuli as well as by GCs. Full article

Extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitors show therapeutic potential in triple-negative breast cancer (TNBC), but resistance through compensatory signaling limits their efficacy. We previously identified the secretory carrier membrane protein 3 (SCAMP3) as a regulator of TNBC progression and ERK1/2 activation. Here, we investigated the role of SCAMP3 in ERK1/2 signaling and therapeutic response using TMT-based LC-MS/MS phosphoproteomics of wild-type (WT) and SCAMP3 knockout (SC3KO) SUM-149 cells under basal conditions, after epidermal growth factor (EGF) stimulation, and during ERK1/2 inhibition with MK-8353. A total of 4408 phosphosites were quantified, with 1093 significantly changed. SC3KO abolished residual ERK activity under MK-8353 and affected the compensatory activation of oncogenic pathways observed in WT cells. SC3KO reduced the phosphorylation of ERK feedback regulators RAF proto-oncogene serine/threonine-protein kinase Raf-1 (S43) and the dual-specificity mitogen-activated protein kinase kinase 2 (MEK2) (T394), affected other ERK targets, including nucleoporins, transcription factors, and metabolic enzymes triosephosphate isomerase (TPI1) (S21) and ATP-citrate lyase (ACLY) (S455). SCAMP3 loss also impaired the mammalian target of rapamycin complex I (mTORC1) signaling and disrupted autophagic flux, evidenced by elevated sequestosome-1 (SQSTM1/p62) and microtubule-associated protein light chain 3 (LC3B-II) with reduced levels of the autophagosome lysosome maturation marker, Rab7A. Beyond ERK substrates, SC3KO affected phosphorylation events mediated by other kinases. These findings position SCAMP3 as a central coordinator of ERK signaling and autophagy. Our results support SCAMP3 as a potential therapeutic target to enhance ERK1/2 inhibitor clinical efficacy and overcome adaptive resistance mechanisms in TNBC. Full article

Cellular redox pathways are critical regulators of various biological processes, including the intricate modulation of intracellular signaling pathways. This review explores how major redox enzymes—such as catalase, superoxide dismutases, glutathione peroxidases, thioredoxins, and peroxiredoxins—interact with key cellular signaling pathways, including receptor tyrosine kinase, mTORC1/AMPK, Wnt/β-catenin, TGF-β/SMAD, NF-κB, Hedgehog, Notch, and GPCR signaling. By investigating mechanisms such as ROS-mediated activation, cysteine oxidation, spatial enzyme localization, and phosphatase regulation, we demonstrate the extensive influence of redox balance on cellular signaling dynamics. Understanding these redox-dependent interactions provides insights into pathophysiological conditions ranging from cancer to fibrosis, offering novel therapeutic opportunities. Full article

The aim of this study was to investigate the clinical and prognostic significance of the NOTCH1 pathway in oral squamous cell carcinoma (OSCC). To this end, the expression of NOTCH1 and two downstream targets, HES1 and p21, was evaluated by immunohistochemistry in 165 OSCC patient specimens. Clinicopathological associations and impact on survival were assessed. Possible mechanistic crosstalk with epithelial–mesenchymal transition (EMT) induction through combined E-cadherin and Vimentin markers, or mTORC1 activation by means of phospho-S6 expression were also investigated. NOTCH1 staining was detected in 56 (35%) tumors, nuclear HES1 in 131 (81%) and nuclear p21 in 116 (70%) tumors. p21 was strongly correlated with mTORC1 activation and HES1 expression was inversely associated with EMT status. NOTCH1 expression was positively associated with an advanced T stage, neck lymph node metastasis, advanced TNM stage, second primary cancer, and was significantly associated with shorter disease-specific survival (DSS). By contrast, HES1 and p21 expression showed significant associations with early clinical stages, and combined p21 and pS6 expression (p21+/p-S6+) distinguished good-prognosis patients. Multivariate Cox analysis further revealed NOTCH1 expression as a significant independent predictor of poor DSS. Mechanistically, we found a strong link between p21 and pS6 proteins, which could potentially serve as a good-prognosis classifier for OSCC patients. Full article