Search Results (1,259)

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive malignancy characterized by complex interactions within the tumor microenvironment (TME) that facilitate immune evasion and tumor progression. The TME consists of diverse cellular components, including cancer-associated fibroblasts, immune and endothelial cells, and extracellular matrix elements, that collectively modulate tumor growth, metastasis, and resistance to therapy. Immune evasion in HNSCC is orchestrated through multiple mechanisms, including the suppression of cytotoxic T lymphocytes, recruitment of immunosuppressive cells, such as regulatory T and myeloid-derived suppressor cells, and upregulation of immune checkpoint molecules (e.g., PD-1/PD-L1 and CTLA-4). Natural killer (NK) cells, which play a crucial role in anti-tumor immunity, are often dysfunctional within the HNSCC TME due to inhibitory signaling and metabolic constraints. Additionally, endothelial cells contribute to tumor angiogenesis and immune suppression, further exacerbating disease progression. Recent advancements in immunotherapy, particularly immune checkpoint inhibitors and NK cell-based strategies, have shown promise in restoring anti-tumor immunity. Moreover, TP53 mutations, frequently observed in HNSCC, influence tumor behavior and therapeutic responses, highlighting the need for personalized treatment approaches. This review provides a comprehensive analysis of the molecular and cellular mechanisms governing immune evasion in HNSCC with a focus on novel therapeutic strategies aimed at improving patient outcomes. Full article

Cellular senescence is closely connected with cancer progression, recurrence, and metastasis. Senotherapy aims to soothe the harmful effects of senescent cells either by inducing their apoptosis (senolytic) or by suppressing the senescence-associated secretory phenotype (SASP) (senomorphic). Fisetin, a well-studied senotherapeutic drug, was selected for this study to evaluate its efficiency when delivered in a liposomal formulation. The experiment evaluated the impact of liposome-encapsulated fisetin on senescent cells induced by doxorubicin (DOX) from two cell lines: WI-38 (normal lung fibroblasts) and A549 (lung carcinoma). Senescence was characterized by SA-β-galactosidase (SA-β-gal) activity, proliferation, morphology, and secretion of pro-inflammatory interleukin 6 (IL-6) and interleukin 8 (IL-8). Due to fisetin’s hydrophobic nature, it was encapsulated in liposomes to enhance cellular delivery. Cellular uptake studies confirmed that the liposomes were effectively internalized by both senescent cell types. Treatment with fisetin-loaded liposomes revealed a lack of senolytic effects but showed senomorphic activity, as evidenced by a significant reduction in IL-6 and IL-8 secretion in senescent cells. The liposomal formulation enhanced fisetin’s therapeutic efficacy, showing comparable results even at the lowest tested concentration. Full article

Lung cancer is one of the most common cancers and the leading cause of cancer-related death worldwide. Despite advancements, the overall survival rate for lung cancer remains between 10% and 20% in most countries. However, recent progress in diagnostic tools and therapeutic strategies has led to meaningful improvements in survival outcomes, highlighting the growing importance of personalized management based on accurate disease assessment. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has become essential in the management of lung cancer, serving as a key imaging modality for initial diagnosis, staging, treatment response assessment, and follow-up evaluation. Recent developments in radiomics and artificial intelligence (AI), including machine learning and deep learning, have revolutionized the analysis of complex imaging data, enhancing the diagnostic and predictive capabilities of FDG PET/CT in lung cancer. However, the limitations of FDG, including its low specificity for malignancy, have driven the development of novel oncologic radiotracers. One such target is fibroblast activation protein (FAP), a type II transmembrane glycoprotein that is overexpressed in activated cancer-associated fibroblasts within the tumor microenvironment of various epithelial cancers. As a result, FAP-targeted radiopharmaceuticals represent a novel theranostic approach, offering the potential to integrate PET imaging with radioligand therapy (RLT). In this review, we provide a comprehensive overview of FDG PET/CT in lung cancer, along with recent advances in AI. Additionally, we discuss FAP-targeted radiopharmaceuticals for PET imaging and their potential application in RLT for the personalized management of lung cancer. Full article

Cutaneous malignant melanoma is an extraordinarily aggressive and heterogeneous cancer that contains a small subpopulation of tumor stem cells (CSCs) responsible for tumor initiation, metastasis, and recurrence. Identification and characterization of CSCs in melanoma is challenging due to tumor heterogeneity and the lack of specific markers (CD271, ABCB5, ALDH, Nanog) and the ability of cells to dynamically change their phenotype. Phenotype-maintaining signaling pathways (Wnt/β-catenin, Notch, Hedgehog, HIF-1) promote self-renewal, treatment resistance, and epithelial–mesenchymal transitions. Tumor plasticity reflects the ability of differentiated cells to acquire stem-like traits and phenotypic flexibility under stress conditions. The interaction of CSCs with the tumor microenvironment accelerates disease progression: they induce the formation of cancer-associated fibroblasts (CAFs) and neo-angiogenesis, extracellular matrix remodeling, and recruitment of immunosuppressive cells, facilitating immune evasion. Emerging therapeutic strategies include immunotherapy (immune checkpoint inhibitors), epigenetic inhibitors, and nanotechnologies (targeted nanoparticles) for delivery of chemotherapeutic agents. Understanding the role of CSCs and tumor plasticity paves the way for more effective innovative therapies against melanoma. Full article

Background/Objectives: After diagnosis, it is common for women with breast cancer to gain weight, which is associated with worse clinical outcomes. However, traditional measures such as body weight, BMI, and waist circumference do not detect key changes in body composition, such as fat redistribution or muscle loss. The objective of this exploratory study was to assess the evolution of body composition and muscle strength after one year of treatment, and their relationship with metabolic biomarkers. Methods: Prospective observational study in newly diagnosed breast cancer patients. Body composition was assessed using bioelectrical impedance analysis (BIA) and ultrasound (US); muscle strength was measured by handgrip dynamometry. Biomarkers analyzed included glucose, insulin, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), glycosylated hemoglobin (HbA1c), total cholesterol (and its fractions), triglycerides, C-reactive protein (CRP), 6-interleukin (IL-6), vitamin D, myostatin, and fibroblast growth factor 21 (FGF-21). Results: Sixty-one women (mean age 58 years) were included. After one year, fat mass and related parameters significantly increased, while skeletal muscle mass and muscle strength decreased. Sarcopenic obesity prevalence rose from 1.16% to 4.9%. No significant changes were found in biomarkers, but positive correlations were observed between fat parameters and insulin, HOMA-IR, and triglycerides, and negative correlations with HDL-cholesterol. Conclusions: BIA and US can detect unfavorable changes in body composition that are not reflected in conventional measurements. At one year post-diagnosis, women showed increased fat accumulation, muscle loss, and reduced strength, even without significant metabolic biomarker changes. Further research is warranted to elucidate the long-term clinical implications of these findings and the external validity in larger cohorts. Full article

Targeted radioligand therapy (RLT) is an emerging field in anticancer therapeutics with great potential across tumor types and stages of disease. While much progress has focused on agents targeting somatostatin receptors and prostate-specific membrane antigen (PSMA), the same advanced radioconjugation methods and molecular targeting have spurred the development of numerous theranostic combinations for other targets. A number of the most promising agents have progressed to clinical trials and are poised to change the landscape of positron emission tomography (PET) imaging. Here, we present recent data on some of the most important emerging molecular targeted agents with their exemplar clinical images, including agents targeting fibroblast activation protein (FAP), hypoxia markers, gastrin-releasing peptide receptors (GRPrs), and integrins. These radiopharmaceuticals share the promising characteristic of being able to image multiple types of cancer. Early clinical trials have already demonstrated superiority to ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) for some, suggesting the potential to supplant this longstanding PET radiotracer. Here, we provide a primer for practicing radiologists, particularly nuclear medicine clinicians, to understand novel PET imaging agents and their clinical applications, as well as the availability of companion targeted radiotherapeutics, the status of their regulatory approval, the potential challenges associated with their use, and the future opportunities and perspectives. Full article

Cancer is no longer considered as an isolated event. Rather, it occurs because of a complex biological drive orchestrating different cell types, growth factors, cytokines, and signaling pathways within the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are the most populous stromal cells within the complex ecosystem of TME, with significant heterogeneity and plasticity in origin and functional phenotypes. Very enigmatic cells, CAFs determine the progress and outcomes of tumors through extensive reciprocal signaling with different tumors infiltrating immune cells in the TME. In their biological drive, CAFs release numerous chemical mediators and utilize various signaling pathways to recruit and modulate tumor-infiltrating immune cells. The CAF-induced secretome and exosomes render immune cells ineffective for their antitumor activities. Moreover, by upregulating immune inhibitory checkpoints, CAFs create an immunosuppressive TME that impedes the susceptibility of tumor cells to tumor-infiltrating lymphocytes (TILs). Further, by depositing and remodeling extracellular matrix (ECM), CAFs reshape the TME, which enhances tumor growth, invasion, metastasis, and chemoresistance. Understanding of CAF biology and its crosstalk with tumor-infiltrating immune cells is crucial not only to gain insight in tumorigenesis but to optimize the potential of novel targeted immunotherapies for cancers. The complex relationships between CAFs and tumor-infiltrating immune cells remain unclear and need further study. Herein, in this narrative review we have focused on updates of CAF biology and its interactions with tumor-infiltrating immune cells in generating immunosuppressive TME and resistance to cell death. Full article

Background: Lysosomal-associated membrane protein 1 (LAMP1), typically localized to the lysosomal membrane, is increasingly implicated as a marker of cancer aggressiveness and metastasis when expressed on the cell surface. This study aimed to develop a LAMP1-targeted antibody-based PET tracer and assess its efficacy in mouse models of human breast and colon adenocarcinoma. Methods: To determine the source of LAMP1 expression, we utilized human single-cell RNA sequencing and spatial transcriptomics, complemented by in-house flow cytometry on xenografted mouse models. Tissue microarrays of multiple epithelial cancers and normal tissue were stained for LAMP-1, and staining was quantified. An anti-LAMP1 monoclonal antibody was conjugated with desferrioxamine (DFO) and labeled with zirconium-89 (⁸⁹Zr). Human triple-negative breast cancer (MDA-MB-231) and colon cancer (Caco-2) cell lines were implanted in nude mice. PET/CT imaging was conducted at 24, 72, and 168 h post-intravenous injection of ⁸⁹Zr-DFO-anti-LAMP1 and ⁸⁹Zr-DFO-IgG (negative control), followed by organ-specific biodistribution analyses at the final imaging time point. Results: Integrated single-cell and spatial RNA sequencing demonstrated that LAMP1 expression was localized to myeloid-derived suppressor cells (MDSCs) and cancer-associated fibroblasts (CAFs) in addition to the cancer cells. Tissue microarray showed significantly higher staining for LAMP-1 in tumor tissue compared to normal tissue (3986 ± 2635 vs. 1299 ± 1291, p < 0.001). Additionally, xenograft models showed a significantly higher contribution of cancer cells than the immune cells to cell surface LAMP1 expression. In vivo, PET imaging with ⁸⁹Zr-DFO-anti-LAMP1 PET/CT revealed detectable tumor uptake as early as 24 h post-injection. The ⁸⁹Zr-DFO-anti-LAMP1 tracer demonstrated significantly higher uptake than the control ⁸⁹Zr-DFO-IgG in both models across all time points (MDA-MB-231 SUV_max at 168 h: 12.9 ± 5.7 vs. 4.4 ± 2.4, p = 0.003; Caco-2 SUV_max at 168 h: 8.53 ± 3.03 vs. 3.38 ± 1.25, p < 0.01). Conclusions: Imaging of cell surface LAMP-1 in breast and colon adenocarcinoma is feasible by immuno-PET. LAMP-1 imaging can be expanded to adenocarcinomas of other origins, such as prostate and pancreas. 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

Background/Objectives: This review discusses the resistance mechanisms in the tumor microenvironment (TME) of malignant melanoma that disrupt the efficacy of immune checkpoint inhibitors (ICIs). In this review, we focus on the roles of immune cells, including tumor-infiltrating lymphocytes (TILs), macrophages, dendritic cells, and other signaling pathways. We explore the interplay between innate and adaptive immunity in the TME and tumor intrinsic resistance mechanisms, such as β-catenin, which has future implications for the usage of ICIs in patients with therapy-resistant tumors. Methods: A total of 1052 studies were extracted from the PubMed database searching for keywords and phrases that included [melanoma AND immune checkpoint inhibitor resistance]. After a title/abstract and full-text review, 101 studies were identified that fit the inclusion/exclusion criteria. Results: Cancer-associated fibroblasts (CAFs), M2 macrophages, and myeloid-derived suppressor cells (MDSCs) are significant in remodeling the TME to promote melanoma growth. Melanoma resistance to ICIs is complex and involves TME alterations, tumor intrinsic factors, and immune evasion. Key components of resistance include reduced CD8+ T cell infiltration, decreased host immune response, and immunosuppressive cytokines. Conclusions: Predictive biomarkers and specific models are the future of individualized melanoma management and show great promise in their approach to targeted therapy production. Tumor profiling can be utilized to help predict the efficacy of ICIs, and specific biomarkers predicting therapy responses are instrumental in moving towards personalized and more efficacious medicine. As more melanoma resistance emerges, alternative and combinatorial therapy based on knowledge of existing resistance mechanisms will be needed. Full article

Background/Objectives: Subcutaneous tumor models are widely used in colorectal cancer (CRC) research due to their experimental accessibility; however, the spatial organization and regulatory mechanisms of their tumor microenvironment remain poorly understood. Methods: Here, we applied spatial transcriptomics to systematically characterize spatial heterogeneity within MC38 subcutaneous tumors in a syngeneic mouse model. Results: We identified two spatially distinct tumor zones, partitioned by cancer-associated fibroblasts (CAFs), that differ markedly in cellular composition, oncogenic signaling, immune infiltration, and metabolic states. One zone exhibited features of TGF-β-driven extracellular matrix remodeling, immune exclusion, and hyperproliferative metabolism, while the other was enriched for immunosuppressive macrophages, metabolic reprogramming via PPAR and AMPK pathways, and high-risk cell populations. Spatially resolved cell–cell communication networks further revealed zone-specific ligand–receptor interactions—such as ANGPTL4–SDC2 and PROS1–AXL—that underpin stromal remodeling and immune evasion and are associated with patient prognosis. Conclusions: Collectively, our study uncovers how region-specific cellular ecosystems and intercellular crosstalk establish prognostically divergent niches within subcutaneous CRC tumors, offering insights into spatially guided therapeutic strategies. Full article

Background/Objectives: Prostate cancer (PCa) is diagnosed at an earlier median age, more advanced stage, and has worse clinical outcomes in African American (AA) men compared to European Americans (EA). Methods: To investigate the role of aberrant DNA methylation in tumor-adjacent stroma (TAS), methyl binding domain sequencing (MBD-seq) was performed on AA (n = 17) and EA (n = 15) PCa patients. This was independently confirmed using the long interspersed nuclear element-1 (LINE-1) assay. Pathway analysis was performed on statistically significantly differentially methylated genes for AA and EA TAS. DNA methylation profiles of primary cultured AA and EA carcinoma-associated fibroblasts (CAFs) were compared with AA and EA TAS. AA and EA CAFs were treated with demethylating agent 5-Azacytidine (5-AzaC). Results: AA TAS exhibited higher global DNA methylation than EA TAS (p-value < 0.001). Of the 3268 differentially methylated regions identified (DMRs, p-value < 0.05), 85% (2787 DMRs) showed increased DNA methylation in AA TAS, comprising 1648 genes, of which 1379 were protein-coding genes. Based on DNA methylation levels, two AA subgroups were identified. Notably, AA patients with higher DNA methylation were predominantly those with higher Gleason scores. Pathway analysis linked methylated genes in AA TAS to several key signaling pathways (p-value < 0.05), including immune response (e.g., IL-1, IL-15, IL-7, IL-8, IL-3, and chemokine), Wnt/β-catenin, androgen, PTEN, p53, TGF-β, and circadian clock regulation. A total of 168 concordantly methylated genes were identified, with 109 genes (65%) showing increased methylation in AA CAFs and TAS (p-value < 0.05). Treatment with 5-AzaC significantly reduced DNA methylation of concordant genes in AA CAFs (p-value < 0.001). Conclusions: These findings suggest a distinct stromal methylome in AA, providing a foundation for integrating demethylating agents into standard therapies. This approach targets the tumor microenvironment, potentially addressing PCa disparities in AA men. Full article

Background: Hypoxia and immune components significantly shape the tumor microenvironment and influence prognosis and immunotherapy response in gastric cancer (GC). This study aimed to develop hypoxia- and immune-related gene signatures for prognostic evaluation in GC. Methods: Transcriptomic data from TCGA-STAD were integrated with hypoxia- and immune-related genes from InnateDB and MSigDB. A prognostic gene signature was constructed using Cox regression analyses and validated on an independent GSE84437 cohort and single-cell RNA dataset. We further analyzed immune cell infiltration, molecular characteristics of different risk groups, and their association with immunotherapy response. Single-cell RNA-seq data from the TISCH database were used to explore gene expression patterns across cell types. Results: Five genes (TGFB3, INHA, SERPINE1, GPC3, SRPX) were identified. The risk score effectively stratified patients by prognosis, with the high-risk group showing lower overall survival and lower T-cell expression. The gene signature had an association with immune suppression, ARID1A mutation, EMT features, and poorer response to immunotherapy. Gene signature, especially SRPX was enriched in fibroblasts. Conclusions: We developed a robust hypoxia- and immune-related gene signature that predicts prognosis and may help guide immunotherapy strategies for GC patients. Full article

Cutaneous melanoma is an aggressive cancer with an increasing incidence worldwide, highlighting the need for research into its pathogenesis. The tumor microenvironment (TME) plays a critical role in melanoma progression and consists of cellular components and an extracellular matrix (ECM) rich in cytokines and signaling molecules. The most abundant stromal cells within the TME are cancer-associated fibroblasts (CAFs), which remodel the ECM and modulate immune responses. Among immune cells, tumor-associated macrophages (TAMs) predominate, and their polarization toward the M2 phenotype supports tumor progression. Tumor-infiltrating lymphocytes (TILs) have diverse functions, including cytotoxic T-cells, helper T-cells that modulate immune response, B-cells forming tertiary lymphoid structures (TLS), and regulatory T-cells with immunosuppressive properties. Dendritic cells (DCs) also play a complex role in the TME. A notable subpopulation are mature regulatory dendritic cells (mregDCs), which contribute to immune evasion. All of these TME components may drive tumorigenesis. Advancements in melanoma treatment—including immunotherapy and targeted therapies—have significantly improved outcomes in advanced-stage disease. In parallel, emerging approaches targeting the tumor microenvironment and gut microbiome, as well as personalized strategies such as neoantigen vaccines and cell-based therapies, are under active investigation and may further enhance therapeutic efficacy in the near future. Full article

High-grade serous ovarian cancer (HGSOC) is an aggressive gynecological malignancy characterized by intraperitoneal spread and chemotherapy resistance. Chemotherapies have demonstrated limited effectiveness in HGSOC, underscoring the urgent need to evaluate how the tumor microenvironment (TME) was reshaped by chemotherapy in different sites of tumor foci. In this study, we performed single-cell transcriptomic analysis to explore the TME in samples obtained from various sites of tumor foci, with or without the history of Neoadjuvant chemotherapy (NACT). We discovered that chemotherapy reshaped the tumor immune microenvironment, evident through the reduction in human leukocyte antigen (HLA) diversity and the increase in PDCD1/CD274 in CD8_ANXA1, LAMP3+ dendritic cell (DC_LAMP3), and EREG+ monocytes (mono_EREG). Moreover, cancer.cell.2, cancer-associated C3+ fibroblasts (CAF_C3), and Fibrocyte_CD34, which are prone to accumulate in the metastatic site and post-NACT group, harbored poor clinical outcome, reflected in the immune exclusion and tumor progression signaling. Cell–cell communication identified a stronger interaction between cancer.cell.2 and CAF_C3, as well as Fibrocyte_CD34, in post-NACT samples, indicating that chemotherapy reshapes pre-existing cell clusters in a site-dependent manner. Our findings suggest that chemotherapy and sites of foci were critical for the transcriptional reprogramming of pre-existed cell clusters. Our study offers a single-cell phenotype data substrate from which to develop a personalized combination of chemotherapy and immunotherapy. Full article