Search Results (101)

Bone metastases mark a critical and often terminal phase in cancer progression, where disseminated tumor cells (DTCs) manage to infiltrate and exploit the complex microenvironments of the bone marrow. While most current therapies focus on the well-known late-stage “vicious cycle” of osteolysis, they often overlook the earlier stages, namely, tumor cell colonization and dormancy. During these early phases, cancer cells co-opt hematopoietic stem cell (HSC) niches, using them as sanctuaries for long-term survival. In this review, we bring together emerging insights that highlight a trio of underappreciated cellular players in this metastatic takeover: megakaryocytes, erythroid lineage cells, and perivascular stromal subsets. Far from being passive bystanders, these cells actively shape the metastatic niche. For instance, megakaryocytes and platelets go beyond their role in transport; they orchestrate immune evasion and dormancy through mechanisms such as transforming growth factor-β1 (TGF-β1) signaling and the physical shielding of tumor cells. In parallel, we uncover a distinct “erythroid-immune” axis: here, stress-induced CD71⁺ erythroid progenitors suppress T-cell responses via arginase-mediated nutrient depletion and checkpoint engagement, forming a potent metabolic barrier against immune attack. Furthermore, leptin receptor–positive (LepR⁺) perivascular stromal cells emerge as key structural players. These stromal subsets not only act as anchoring points for DTCs but also maintain them in protective vascular zones via CXCL12 chemokine gradients. Altogether, these findings reveal that the metastatic bone marrow niche is not static; it is a highly dynamic, multi-lineage ecosystem. By mapping these intricate cellular interactions, we argue for a paradigm shift: targeting these early and cooperative crosstalk, whether through glycoprotein-A repetitions predominant (GARP) blockade, metabolic reprogramming, or other niche-disruptive strategies, could unlock new therapeutic avenues and prevent metastatic relapse at its root. Full article

Advanced prostate cancer, particularly castration-resistant disease, remains challenging to treat due to intratumoral heterogeneity, immune exclusion, and a suppressive tumor microenvironment. Within this ecosystem, cancer-associated fibroblasts shape tumor–stroma communication, but their marked heterogeneity and plasticity complicate classification and make indiscriminate fibroblast depletion potentially ineffective or even harmful. This review summarizes recent progress in fibroblast origins, functional subtypes, and fibroblast-driven mechanisms that promote tumor progression and therapy resistance, as well as emerging therapeutic opportunities in prostate cancer. We conducted a structured literature search of PubMed, ScienceDirect, and major publisher platforms (including Nature and SpringerLink) from database inception to 15 February 2025, supplemented by targeted manual screening of reference lists. Evidence from single-cell/spatial-omics and mechanistic studies indicates that prostate tumors contain multiple fibroblast programs that occupy distinct niches yet can interconvert. Across these studies, it was found that these fibroblasts contribute to immune suppression, extracellular matrix remodeling and stromal barrier formation, angiogenesis, and metabolic support, collectively limiting drug penetration and reinforcing immune evasion; therapeutic pressure can further rewire fibroblast states and resistance-associated signaling. Overall, the literature supports a shift toward function- and subtype-directed intervention rather than “one-size-fits-all” targeting, with promising directions including precision targeting and reversible reprogramming, rational combination strategies, and localized delivery approaches that reduce stromal barriers while preserving tissue homeostasis in high-risk and treatment-refractory prostate cancer. Full article

An underdeveloped placental vasculature is a cardinal feature in severe, early-onset fetal growth restriction with absent/reversed umbilical artery Doppler end-diastolic velocities (FGR_a/r). Tissue microenvironment is a key mediator of angiogenesis; yet, the role of placental villous stromal extracellular matrix (ECM) in FGR_a/r remains unknown. We applied an ECM-optimized, proteomic workflow to villous tissue and placental fibroblast cell-derived matrices (CDM) from FGR_a/r, gestational age-matched controls, and uncomplicated term pregnancies. No significant differences were detected in villous tissue, although there was a trend toward increased type I collagen and fibronectin in FGR_a/r placentas. FGR_a/r CDM, however, appeared distinct from both control groups, with elevated matrisome abundance, greater insolubility of matrisome-associated proteins, and 44 differentially expressed matrisome proteins. Fibronectin emerged as a central network hub among differential matrisome proteins, interacting with thrombospondin-1, vitronectin, and transglutaminase-2, all of which were enriched in FGR_a/r CDM, suggesting excessive deposition and crosslinking. In contrast, regulators of ECM remodeling and TGFβ activity, including fibrillin-1, decorin, and syndecan-4, were depleted. These features suggest a pro-fibrotic, dysregulated stroma with diminished remodeling capacity. Our findings establish the first, comprehensive proteomic map of human placental stromal matrisome and provide a molecular framework for understanding how aberrant ECM organization contributes to placental dysfunction. Full article

Background. The dense hyaluronan (HA)-rich stroma in solid tumors can prevent effective tumor growth inhibition by hindering drug delivery and immune cell infiltration. However, the degradation of HA alone by systemic delivery of hyaluronidase has not shown significant improvement of tumor growth inhibition. Objectives/Methods. In this study, we targeted hyaluronan degradation by using antibody–enzyme (AbEn) molecules by fusing antibodies to a recombinant human hyaluronidase (HYAL). Results. The AbEn molecules were stable, retained both antigen-binding and enzymatic activities, and demonstrated a prolonged serum half-life of 132 h in rodent models. In the HA-rich colorectal cancer model, the cancer-associated fibroblast (CAF)-directed AbEn, TAVO423 (FAP × LRRC15 × HYAL trispecific antibody) achieved greater intratumoral HA depletion resulting in superior tumor growth inhibition compared to untargeted HYAL. Furthermore, the combination of TAVO423 in combination with other solid tumor cell targeting modalities such as 5-fluorouracil (5-FU), anti-PD-L1 monoclonal antibody, a PD-L1 × CD3 bispecific T-cell engager (TCE), and a CD318-targeting antibody–drug conjugate (ADC) all demonstrated enhanced tumor growth inhibition (TGI) values of 49–67% as compared to the respective monotherapy TGI values of 1–28%. In addition, TAVO423 improved the antitumor response of a 5T4 × CD3 TCE with an increase in TGI from 73% to 92% in an in vivo HA-rich pancreatic cancer model. The CAF-targeted HA degradation mediated by TAVO423 also reversed immune exclusion by increasing the density of CD8⁺ tumor-infiltrating lymphocytes (TILs) by 6–9-fold and synergized with PD-1 blockade to enhance TGI from 33% to 51% in an in vivo immunocompetent EMT-6 breast cancer model. Conclusions. These findings demonstrated the broad potential of the modular AbEn platform for targeted HA degradation to overcome barrier entry in stromal HA-rich solid tumors. Full article

Background: Antibody-drug conjugates (ADCs) have ushered in a new era of precision oncology by combining the targeting specificity of monoclonal antibodies with the potent cytotoxicity of chemotherapeutic drugs. However, the cellular and molecular mechanisms underlying their dose-limiting ocular toxicity remain unclear. Elahere™, the first FDA-approved ADC targeting folate receptor α (FRα), demonstrates remarkable efficacy in platinum-resistant ovarian cancer but causes keratitis and other ocular toxicities in some patients. Notably, FRα is not expressed in the corneal epithelium—the primary site of damage—highlighting the urgent need to elucidate its underlying mechanisms. The aim of this study was to identify the cell-type-specific molecular mechanisms underlying Elahere-induced ocular toxicity. Methods: Sprague-Dawley rats were treated with intravenous Elahere (20 mg/kg) or vehicle weekly for five weeks. Ocular toxicity was determined by clinical examination and histopathology. Corneal single-cell suspensions were analyzed using the BD Rhapsody single-cell RNA sequencing (scRNA-seq) platform. Bioinformatic analyses to characterize changes in corneal cell populations, gene expression, and signaling pathways included cell clustering, differential gene expression, pseudotime trajectory inference, and cell-cell interaction modeling. Results: scRNA-seq profiling of 47,606 corneal cells revealed significant damage to the ocular surface and corneal epithelia in the Elahere group. Twenty distinct cell types were identified. Elahere depleted myeloid immune cells; in particular, homeostatic gene expression was suppressed in phagocytic macrophages. Progenitor populations (limbal stem cells and basal cells) accumulated (e.g., a ~2.6-fold expansion of limbal stem cells), while terminally differentiated cells decreased in corneal epithelium, indicating differentiation blockade. Endothelial cells exhibited signs of injury and inflammation, including reduced angiogenic subtypes and heightened stress responses. Folate receptor alpha, the target of Elahere, was expressed in endothelial and stromal cells, potentially driving stromal cells toward a pro-fibrotic phenotype. Fc receptor genes were predominantly expressed in myeloid cells, suggesting a potential mechanism underlying their depletion. Conclusions: Elahere induces complex, multi-compartmental ocular toxicity characterized by initial perturbations in vascular endothelial and immune cell populations followed by the arrest of epithelial differentiation and stromal remodeling. These findings reveal a cascade of cellular disruptions and provide mechanistic insights into mitigating Elahere-associated ocular side effects. Full article

Cisplatin remains a cornerstone chemotherapeutic agent; however, its off-target gonadotoxicity poses a significant risk for premature ovarian failure (POF) and infertility in young women. Strategies to preserve ovarian function during chemotherapy are critically needed. To investigate the protective effects of krill oil supplementation against cisplatin-induced ovarian damage in a rat model, with a focus on oxidative stress, inflammation, follicular dynamics, and stromal fibrosis. Twenty-one adult female Wistar albino rats were randomized into three groups: control, cisplatin-treated, and cisplatin + krill oil-treated. Ovarian toxicity was induced via intraperitoneal injection of cisplatin (2.5 mg/kg, twice weekly for four weeks). Krill oil (4 mL/kg/day) was administered orally during the same period. Ovarian histopathology, follicle counts (primordial, primary, secondary, tertiary), stromal fibrosis, and biochemical markers, including plasma anti-Müllerian hormone (AMH), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and ovarian levels of nuclear factor erythroid 2-related factor 2 (Nrf2), Toll-like receptor 4 (TLR4), TNF-α, NOD-like receptor family pyrin domain containing 3 (NLRP3), and IL-1β were evaluated. Cisplatin significantly reduced primordial, primary, secondary, and tertiary follicle counts while increasing stromal fibrosis (p < 0.001). Krill oil co-treatment notably ameliorated follicular depletion—improving follicle counts by 38.16%, 54.74%, 62.5%, 40.43%, respectively—and reduced fibrosis (p = 0.017). Biochemically, cisplatin decreased AMH levels and Nrf2 expression while elevating MDA, TNF-α, TLR4, NLRP3, and IL-1β levels (p < 0.001). Krill oil supplementation restored AMH (p = 0.002) and Nrf2 (p = 0.003) levels, while reducing MDA (p = 0.009), NLRP3 (p < 0.001), ovarian IL-1β (p = 0.005), plasma IL-1β (p < 0.001), TLR4 (p = 0.001), plasma TNF-α (p = 0.001), and ovarian TNF-α (p < 0.001), compared to the cisplatin group. Krill oil exerts significant antioxidant and anti-inflammatory effects, offering a promising strategy to mitigate cisplatin-induced ovarian damage and preserve fertility in young cancer patients. Full article

Epithelia contribute to the innate immune system through barrier formation and through signaling to immune cells. When the barrier is breached, epithelial cells undergo epithelial-to-mesenchymal transition (EMT) as part of the wound healing process. EMT is largely directed by signals from the stromal microenvironment, including transforming growth factor beta (TGFβ1), and antagonizes normal epithelial differentiation. How EMT and innate immunity may be connected molecularly has not been explored, although both processes are likely to occur simultaneously. Keratinocytes are the host cell type for human papillomaviruses (HPV), which can induce EMT in certain conditions but also depend on differentiation for their replication. We previously found that the innate immune factor interferon regulatory factor 3 (IRF3) inhibits epithelial differentiation and reduces the expression of HPV16 late genes. Here we report that IRF3 in the stroma compartment promotes an EMT-like pattern of gene expression in an HPV16-containing epithelium. The depletion of stromal IRF3 resulted in the downregulation of TGFβ1-related signaling in both the stroma and epithelium. IRF3 binds to the TGFB1 promoter in human foreskin fibroblasts and is necessary for TGFB1 mRNA production. Because an EMT-like state is unfavorable for differentiation-dependent HPV16, we observed that all EMT markers examined were reduced in the presence of episomal HPV16. Together, we show that stromal IRF3 can disrupt epithelial differentiation and act as an anti-HPV factor through the regulation of EMT, linking wound healing and immunity. Full article

The use of adenosine triphosphate (ATP) has shown promising effects in alleviating ischemic damage across various tissues. However, the penetration of ATP into kidney tubular cells presents a challenge due to their unique anatomical and physiological properties. In this study, we introduce a novel bioinspired drug delivery system utilizing extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) and engineered to carry ATP. ATP-loaded liposomes (ATP-LPs) and ATP-loaded EVs (ATP-EVs) were prepared using microfluidic technology, followed by characterization of their morphology (DLS, NTA, SEM, TEM), ATP content, and release rate at 37 °C (pH 7.4). Additionally, the delivery efficacy of ATP-LPs and ATP-EVs was evaluated in vitro on renal cells (HK2 cells) under chemically induced ischemia. The results indicated successful ATP enrichment in EVs, with ATP-EVs showing no significant changes in morphology or size compared to naïve EVs. Notably, ATP-EVs demonstrated superior ATP retention compared to ATP-LPs, protecting the ATP from degradation in the extracellular environment. In an ATP-depleted HK2 cell model, only ATP-EVs effectively restored ATP levels, preserving cell viability and reducing apoptotic gene expression (BCL2-BAX). This study is the first to successfully demonstrate the direct delivery of ATP into renal tubular cells in vitro using EVs as carriers. Full article

Batch-to-batch reproducibility and robust quality assessment are crucial for producing cell-free biologics, such as conditioned medium (CM) derived from mesenchymal stem/stromal cells (MSCs). This study investigated the effects of freezing CM at −80 °C prior to concentration, a step that could occur in large scale pipelines, compared to freshly processed CM. Quality assessment included total protein quantification; extracellular vesicle evaluation using nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and cytofluorimetry; and biochemical analysis using Raman spectroscopy. The freezing process resulted in a 34% reduction in total protein content, as confirmed for selected bioactive mediators, and significant depletion of specific particle types, particularly larger ones. Interestingly, the total particle concentration and polydispersity remained stable. Alterations in Raman spectra highlighted changes in protein, lipid, and nucleic acid content. These findings demonstrate that even routine steps like freezing can alter CM composition, likely due to temperature-induced structural changes in biological molecules. Careful consideration of pre- and intra-processing handling temperatures is critical for preserving the integrity of CM and ensuring consistent quality. This study emphasizes the importance of refining manufacturing protocols in the production of cell-free biologics. Full article

Background: The metastasis-promoting G-protein-coupled receptor CXC Receptor 4 (CXCR4) is activated by the chemokine CXCL12, also known as stromal cell-derived factor 1 (SDF-1). The CXCL12/CXCR4 pathway in cancer promotes metastasis but the molecular details of how this pathway cross-talks with oncogenes are understudied. An oncogene pathway known to promote breast cancer metastasis in MDA-MB-231 xenografts is that of Mouse Double Minute 2 and 4 (MDM2 and MDM4, also known as MDMX). MDM2 and MDMX promote circulating tumor cell (CTC) formation and metastasis, and positively correlate with a high expression of CXCR4. Interestingly, this MDMX-associated upregulation of CXCR4 is only observed in cells grown in the tumor microenvironment (TME), but not in MDA-MB-231 cells grown in a tissue culture dish. This suggested a cross-talk signaling factor from the TME which was predicted to be CXCL12 and, as such, we asked if the exogenous addition of the cell non-autonomous CXCL12 ligand would recapitulate the MDMX-dependent upregulation of CXCR4. Methods: We used MDA-MB-231 cells and isolated CTCs, with and without MDMX knockdown, plus the exogenous addition of CXCL12 to determine if MDMX-dependent upregulation of CXCR4 could be recapitulated outside of the TME context. We added exogenous CXCL12 to the culture medium used for growth of MDA-MB-231 cells and isogenic cell lines engineered for MDM2 or MDMX depletion. We carried out immunoblotting, and quantitative RT-PCR to compare the expression of CXCR4, MDM2, MDMX, and AKT activation. We carried out Boyden chamber and wound healing assays to assess the influence of MDMX and CXCL12 on the cells’ migration capacity. Results: The addition of the CXCL12 chemokine to the medium increased the CXCR4 cellular protein level and activated the PI3K/AKT signaling pathway. Surprisingly, we observed that the addition of CXCL12 mediated the upregulation of MDM2 and MDMX at the protein, but not at the mRNA, level. A reduction in MDMX, but not MDM2, diminished both the CXCL12-mediated CXCR4 and MDM2 upregulation. Moreover, a reduction in both MDM2 and MDMX hindered the ability of the added CXCL12 to promote Boyden chamber-assessed cell migration. The upregulation of MDMX by CXCL12 was mediated, at least in part, by a step upstream of the proteasome pathway because CXCL12 did not increase protein stability after cycloheximide treatment, or when the proteasome pathway was blocked. Conclusions: These data demonstrate a positive feed-forward activation loop between the CXCL12/CXCR4 pathway and the MDM2/MDMX pathway. As such, MDMX expression in tumor cells may be upregulated in the primary tumor microenvironment by CXCL12 expression. Furthermore, CXCL12/CXCR4 metastatic signaling may be upregulated by the MDM2/MDMX axis. Our findings highlight a novel positive regulatory loop between CXCL12/CXCR4 signaling and MDMX to promote metastasis. Full article

(1) Background: The worldwide endometrial cancer (EC) incidence is rising, amongst others linked to obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome, possibly due to low-grade adipose tissue inflammation. We studied immune cell infiltration in the endometrium in relation to diagnosis and obesity. (2) Methods: A cohort was created (n = 44) from postmenopausal women, lean (n = 15) and obese (n = 29), with bleeding complaints due to EC (n = 18) or benign pathology (n = 26). Endometrial biopsies were used to study the immune microenvironment and stained for macrophages (CD68 and CD163), T-cells (CD3 and CD8), and NK-cells (CD56). (3) Results: Malignant samples showed reduced intraepithelial CD3+ and CD8+ T-cells and increased stromal CD3+ T-cells. In obese patients, increased intraepithelial CD3+ and CD8+ T-cells were detected, especially in obese patients with T2DM. Epithelial CD56+ NK-cells were depleted in EC; however, no effect of obesity on NK-cell infiltration was observed. Stromal CD68+ cells were reduced in EC patients, whereas the CD163+ cells were increased. (4) Conclusions: Obesity and malignancy are associated with differences in immune cell presence. The alterations in immune cell infiltration seen in obese EC patients with and without diabetes suggest a complex interaction where obesity-related low-grade inflammation plays a central role. Full article

As the predominant stromal cells in the ccRCC surrounding environment, cancer-associated fibroblasts (CAFs) have been established as supportive of tumor growth. However, the detailed molecular mechanisms underlying the supporting role of CAFs in ccRCC have not been well characterized. Evidence from the clustering consensus analysis, single-cell analysis, and the experimental results illustrate that CAF-derived FGF7 plays a crucial role as a signaling mediator between CAFs and ccRCC tumor cells. Mechanistically, CAF-derived FGF7 triggers AKT activation to promote cell growth and cell invasion of ccRCC tumor cells. As a response, ccRCC tumor cells stimulate STAT3-mediated transcriptional regulation, directly increasing FGF7 expression at the chromatin level in CAFs. Moreover, there exists a positive clinical correlation between the abundance of CAFs, FGF7 expression, and the infiltration of M2 type macrophages. The RENCA in vivo mouse model also confirmed that FGF7 depletion could impede RCC development by reducing the recruitment of M2 type macrophages. Overall, this study delineates a key signaling axis governing the crosstalk between CAFs and ccRCC tumor cells, highlighting FGF7 as a promising therapeutic target of ccRCC. Full article

Within the tumor microenvironment, myeloid cells constitute a dynamic immune population characterized by a heterogeneous phenotype and diverse functional activities. In this review, we consider recent literature shedding light on the increasingly complex biology of M2-like immunosuppressive tumor-associated macrophages (TAMs), including their contribution to tumor cell invasion and metastasis, stromal remodeling (fibrosis and matrix degradation), and immune suppressive functions, in the tumor microenvironment (TME). This review also delves into the intricate signaling mechanisms underlying the polarization of diverse macrophage phenotypes, and their plasticity. We also review the development of promising therapeutic approaches to target these populations in cancers. The expanding knowledge of distinct subsets of immunosuppressive TAMs, and their contributions to tumorigenesis and metastasis, has sparked significant interest among researchers regarding the therapeutic potential of TAM depletion or phenotypic modulation. Full article

Ceramides regulate phagocytosis; however, their exact function remains poorly understood. Here, we sought (1) to develop genetically encoded fluorescent tools for imaging ceramides, and (2) to use them to examine ceramide dynamics during phagocytosis. Fourteen enhanced green fluorescent protein (EGFP) fusion constructs based on four known ceramide-binding domains were generated and screened. While most constructs localized to the nucleus or cytosol, three based on the CA3 ceramide-binding domain of kinase suppressor of ras 1 (KSR1) localized to the plasma membrane or autolysosomes. C-terminally tagged CA3 with a vector-based (C-KSR) or glycine-serine linker (C-KSR-GS) responded sensitively and similarly to ceramide depletion and accumulation using a panel of ceramide modifying drugs, whereas N-terminally tagged CA3 (N-KSR) responded differently to a subset of treatments. Lipidomic and liposome microarray analysis suggested that, instead, N-KSR may preferentially bind glucosyl-ceramide. Additionally, the three probes showed distinct dynamics during phagocytosis. Despite partial autolysosomal degradation, C-KSR and C-KSR-GS accumulated at the plasma membrane during phagocytosis, whereas N-KSR did not. Moreover, the weak recruitment of C-KSR-GS to the endoplasmic reticulum and phagosomes was enhanced through overexpression of the endoplasmic reticulum proteins stromal interaction molecule 1 (STIM1) and Sec22b, and was more salient in dendritic cells. The data suggest these novel probes can be used to analyze sphingolipid dynamics and function in living cells. Full article

Growth of malignant cells in solid tumors induces changes to the tumor microenvironment (TME). These changes result in promotion of tumor growth, invasion, and metastasis, but also in tumor resistance to drugs and radiotherapy. The enhanced permeability and retention (EPR) effect in neo-angiogenic tumor tissue enables the transport of therapeutic molecules from the circulation into the tumor, but studies show that further diffusion of these agents is often not sufficient for efficient tumor eradication. Despite the hyperpermeable vasculature facilitating the delivery of drugs and tracers, the high density of stromal cells and matrix proteins, in combination with the elevated interstitial fluid pressure in the microenvironment of solid tumors, presents a barrier which limits the delivery of compounds to the core of the tumor. Reversing the cancer-cell-induced changes to the microenvironment as well as novel nanoparticle strategies to circumvent tumor-induced stromal changes have therefore been suggested as potential methods to improve the delivery of therapeutic molecules and drug efficacy. Strategies to modulate the TME, i.e., normalization of tumor vasculature and depletion of excessive stromal proteins and cells, show promising results in enhancing delivery of therapeutic compounds. Modulation of the TME may therefore enhance the efficacy of current cancer treatments and facilitate the development of novel treatment methods as an alternative for invasive resection procedures. Full article