Microenvironmental Factors Research Articles

Abstract B019: Regulatory macrophages contribute to tumor cell plasticity in colorectal cancer metastases

Abstract Metastatic disease is the common cause of death in colorectal cancer. To better understand the cellular landscape of colorectal metastasis, we profiled primary tumors and liver, lung, and peritoneal metastases using single-cell RNA sequencing. Our analysis revealed a subset of tumor epithelial cells with a highly plastic transcription profile and, inversely, low expression of stemness markers. Tumor cells with plasticity markers were spatially enriched at the tumor- stroma interface with exposure to tissue microenvironmental factors. Cell-free malignant ascites, which recapitulates the tumor microenvironment, impaired expression of proliferation and stem- like markers in favor of plasticity markers and enhanced migration of tumor cells. Furthermore, Co-culture of colorectal tumor cells with CD11b+ macrophages isolated from malignant ascites from patients was sufficient to recapitulate tumor cell plasticity. Profiling of tumor-associated macrophages identified enrichment for a lipid-handling features and high spatial correlation with plastic tumor cells. Taken together, we demonstrate that tumor-associated macrophages contribute to disease progression through development of pro-malignant features. Citation Format: Matthew A. Cottam, Muhammad B. Mirza, Emily N. Arner, Marium Siddiqui, Clare Lipscombe, Zaid Hatem, Katy E. Beckermann, Kamran Idrees. Regulatory macrophages contribute to tumor cell plasticity in colorectal cancer metastases [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B019.

Nutritional Status and Anemia among Scheduled Caste Adolescent Girls of District Yamunanagar, Haryana, India

Background: During adolescence, nutrition is crucial for physical and cognitive development, yet socio-economic disparities and nutritional deficiencies, especially in girls, lead to health vulnerabilities, including high anemia rates. Despite recent data from the National Family Health Survey, there is limited information on adolescents aged 11-16 years, requiring targeted research. This cross-sectional study aims to assess the nutritional status, determine the prevalence of anemia, and explore associated factors among adolescent girls of the scheduled caste in District Yamunanagar, Haryana, India. Methods: The study sampled 450 scheduled caste girls aged 11-16 years from schools in District Yamunanagar, Haryana. Height and weight were measured to calculate Body Mass Index (BMI). Data on micro-environmental factors, socio-economic and demographic variables, and dietary habits were collected through interview-based schedule. Hemoglobin levels were measured using Sahli’s Acid Haematin technique, and nutritional status was assessed using the World Health Organization (WHO) standards (Z-score method). Results: The study found increases in height, weight, and BMI with age, with notable spurts at 12-13 years for height and 11-12 years for weight and BMI. Significant differences in height, weight, and BMI were observed between age groups. Moreover, 92.2% girls were found to be anemic, with most of them suffering from moderate anemia. Additionally, the prevalence of stunting was 67.33% and wasting was 64.90% among the girls. Household size, number of family members and menarcheal status of the girls showed a significant association with the nutritional status and anemic of the girls. Conclusion: The study emphasizes the need of regular screening and timely interventions to improve the nutritional and anemic status of adolescent girls.

Abstract B069: Spatial and single-cell proteomic landscaping of the hypoxic microenvironment in glioblastoma

Abstract Glioblastoma (GBM) is a fatal adult solid tumour with median overall survival of 18-20 months post-diagnosis; contributing factors to therapeutic inefficacy include acquisition of genomic alterations post-therapy, immune evasion, deregulated hypervascularization, and tumor microenvironmental factors such as hypoxia. Combined with extensive inter- and intra-tumoral heterogeneity at bulk and single-cell level, hypoxia contributes to a gradient of molecular alterations that are specific to different cell populations that make up tumour bulk and reside in specific niches. Hitherto, high-dimensional histopathologic analyses of hypoxic regions within GBM tissue have not been performed. We took a combined spatial and single-cell proteomic profiling approach to investigate the histopathologic features of hypoxia by leveraging a unique clinical study wherein the exogenous hypoxia marker, pimonidazole (PIMO), was administered to GBM-patients preoperatively. Tissue specimens were subjected to imaging mass cytometry, high-resolution imaging, and serial immunohistochemistry using a panel of markers associated with cellular hallmarks of hypoxia, metabolism, proliferation, stemness, angiogenesis, and immune cell types. Our findings showed that PIMO staining is associated with histopathologic features of hypoxia and correlates with specific metabolic, immune, and stemness markers in GBM; specific lymphocyte populations were depleted from hypoxic regions alongside alterations in macrophagic and microglial landscape in a niche-specific manner; hypoxia reduced the proportion of proliferating glioma initiating cells and altered the proliferative, transcriptional, and translational capacity of different cell populations; microvessel density was reduced in hypoxic microenvironment. Cytometry by time-of-flight further validated the altered proportions of specific immune cell types enriched in hypoxic populations of GBM microenvironment. Our study is the first to report use of PIMO to interrogate spatial, single-cell, and phenotypic architecture associated with tissue hypoxia and altered expression of biomarkers associated with hypoxia/glycolysis, immune infiltration, proliferation, and stemness. Identification of targetable biomarkers and mediators of hypoxia-driven habitats in GBM may provide direction for future immunotherapeutic research. Citation Format: Shreya Gandhi, Sheila Mansouri, Olivia Singh, Mark Zaidi, Ronald Wu, Andrew Gao, Bradley Wouters, Gelareh Zadeh. Spatial and single-cell proteomic landscaping of the hypoxic microenvironment in glioblastoma [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B069.

EPCO-16. METHOD TO MODEL AND CORRECT NOISE IN SINGLE-NUCLEI RNA-SEQUENCING DATA FROM POST-MORTEM BRAIN

Abstract Post-mortem brain samples are crucial for neuropathological research. For brain cancers, they provide insights about disease progression, microenvironmental factors, and treatment resistance. In some brain diseases, brain tissue may only be available post-mortem. Establishing a reference atlas of healthy brain also requires post-mortem donations. Beyond logistical and ethical challenges of post-mortem samples, there are also post-mortem factors that mask biological signal. In this study, we specifically aim to model post-mortem gene expression changes in single-nuclei RNA-sequencing (snRNA-seq) data. We analyze a public snRNA-seq dataset of pediatric high-grade glioma (pHGG) that has matched samples at initial resection and autopsy. We find a clear gene signature, composed of mitochondrial genes, stress-related genes, and metabolism-related genes, that is upregulated post-mortem. This signature also appears in post-mortem snRNA-seq data from other brain diseases and healthy donors. We classify it as “post-mortem noise”. We model the post-mortem noise as a combination of technical and biological artifact. The technical artifact is correlated with the percentage of mitochondrial reads and is a general measure of sample quality. The biological artifact is correlated with post-mortem interval and represents gene expression changes due to post-mortem stress. We apply our model to the pHGG data by regressing out the technical and biological artifact. Removing the post-mortem noise results in an improvement in malignant versus normal cell prediction, cell type classification, and the uncovering of pathways related to glioma progression. We confidently identify several normal cell types and predict their interactions with cancer cells, highlighting the utility of wider possible margins post-mortem. Therefore, after removing post-mortem noise, we analyze glioma progression at an unparalleled timepoint and characterize late-stage changes in the tumor microenvironment. In conclusion, we develop a method that models post-mortem noise in snRNA-seq brain data. Our method can be broadly applied to future brain cancer studies using post-mortem tissue.

CNSC-65. ELECTROPHYSIOLOGICAL AND SPATIAL TRANSCRIPTOMIC PROFILING OF GLIOMA-INFILTRATED CORTEX REVEAL LAYER SPECIFIC ALTERATIONS

Abstract Specialized neocortical circuits selectively organize neuronal signals and encode features of cognitive processing via local and long-range connections. Since glioma-infiltrated cortex is excitable and can participate in cognitive processing, the underlying laminar structure and functionality may still be preserved despite infiltration. Moreover, since glioma cells remodel existing neural circuits and microenvironmental factors drive invasion and proliferation, neuron-glioma interactions may demonstrate layer specificity. As glioma-infiltrated cortex remains poorly understood, we sought to characterize these regions using electrophysiological, structural, and genomic approaches. We assessed the power spectra of normal-appearing and glioma-infiltrated cortex using magnetoencephalography and subdural high-density electrode arrays. Immunohistochemistry of formalin-fixed paraffin-embedded (FFPE) samples of infiltrated cortex enabled protein-level neuronal and glioma identification to determine laminar preservation and spatial invasion patterns. Spatial transcriptomics of FFPE tissues and single-nucleus RNA-sequencing were used to identify cell populations, genomic alterations, and cell-cell communication within and across samples at testing and validation sites across the US and Europe. Increased delta range (1-4 Hz) power and decreased power in the beta range (12-20 Hz), activity thought to originate from deep layers, were identified as robust features of infiltrated cortex which were maintained across glioma subtypes (n = 139 patients) and preserved in a validation cohort (n = 8 patients). Immunohistochemistry revealed greater tumor burden within deep laminae regardless of glioma subtype (n = 20 samples). Tissue proteomics and spatial genomics analyses performed using glioma-infiltrated cortical samples (n = 10 samples; 29,011 spots) confirmed routine preservation of laminar organization, greater tumor burden in deep layers, as well as layer specific differences in glioma-related expression programs. Cell-cell communication analyses demonstrated increased interactions in glioma-infiltrated cortex across layers. These findings suggest that laminar structure may be preserved in glioma-infiltrated cortex while remodeling of neural circuits alters spatiotemporal activity in a predictable manner and support a deep to superficial invasion pattern. Thus, investigating glioma infiltration using layer-centric approaches may facilitate novel insights into neuron-glioma interactions.

Discovery of miRNA-mRNA regulatory networks in glioblastoma reveals novel insights into tumor microenvironment remodeling.

Adult glioblastoma (GBM) is a highly aggressive primary brain tumor, accounting for nearly half of all malignant brain tumors, with a median survival rate of only 8months. Treatment for GBM is largely ineffective due to the highly invasive nature and complex tumor composition of this malignancy. MicroRNAs (miRNA) are short, non-coding RNAs that regulate gene expression by binding to messenger RNAs (mRNA). While specific miRNA have been associated with GBM, their precise roles in tumor development and progression remain unclear. In this study, the analysis of miRNA expression data from 743 adult GBM cases and 59 normal brain samples identified 94 downregulated miRNA and 115 upregulated miRNA. Many of these miRNA were previously linked to GBM pathology, confirming the robustness of our approach, while we also identified novel miRNA that may act as potential regulators in GBM. By integrating miRNA predictions with gene expression data, we were able to associate downregulated miRNA with tumor microenvironment factors, including extracellular matrix remodeling and signaling pathways involved in tumor initiation, while upregulated miRNA were found to be associated with essential neuronal processes. This analysis highlights the significance of miRNA in GBM and serves as a foundation for further investigation.

From precursor to cancer: decoding the intrinsic and extrinsic pathways of pancreatic intraepithelial neoplasia progression.

This review explores the progression of pancreatic intraepithelial neoplasia (PanIN) to pancreatic ductal adenocarcinoma through a dual lens of intrinsic molecular alterations and extrinsic microenvironmental influences. PanIN development begins with Kirsten rat sarcoma viral oncogene (KRAS) mutations driving PanIN initiation. Key additional mutations in cyclin-dependent kinase inhibitor 2A (CDKN2A), tumor protein p53 (TP53), and mothers against decapentaplegic homolog 4 (SMAD4) disrupt cell cycle control and genomic stability, crucial for PanIN progression from low-grade to high-grade dysplasia. Additional molecular alterations in neoplastic cells, including epigenetic modifications and chromosomal alterations, can further contribute to neoplastic progression. In parallel with these alterations in neoplastic cells, the microenvironment, including fibroblast activation, extracellular matrix remodeling, and immune modulation, plays a pivotal role in PanIN initiation and progression. Crosstalk between neoplastic and stromal cells influences nutrient support and immune evasion, contributing to tumor development, growth, and survival. This review underscores the intricate interplay between cell-intrinsic molecular drivers and cell-extrinsic microenvironmental factors, shaping PanIN predisposition, initiation, and progression. Future research aims to unravel these interactions to develop targeted therapeutic strategies and early detection techniques, aiming to alleviate the severe impact of pancreatic cancer by addressing both genetic predispositions and environmental influences.

Cells and signals of the leukemic microenvironment that support progression of T-cell acute lymphoblastic leukemia (T-ALL).

Current intensified chemotherapy regimens have significantly increased survival rates for pediatric patients with T-cell acute lymphoblastic leukemia (T-ALL), but these treatments can result in serious adverse effects; furthermore, patients who are resistant to chemotherapy or who relapse have inferior outcomes, together highlighting the need for improved therapeutic strategies. Despite recent advances in stratifying T-ALL into molecular subtypes with distinct driver mutations, efforts to target the tumor-intrinsic genomic alterations critical for T-ALL progression have yet to translate into more effective and less toxic therapies. Ample evidence now indicates that extrinsic factors in the leukemic microenvironment are critical for T-ALL growth, infiltration, and therapeutic resistance. Considering the diversity of organs infiltrated by T-ALL cells and the unique cellular components of the microenvironment encountered at each site, it is likely that there are both shared features of tumor-supportive niches across multiple organs and site-specific features that are key to leukemia cell survival. Therefore, elucidating the distinct microenvironmental cues supporting T-ALL in different anatomic locations could reveal novel therapeutic targets to improve therapies. This review summarizes the current understanding of the intricate interplay between leukemia cells and the diverse cells they encounter within their tumor microenvironments (TMEs), as well as opportunities to therapeutically target the leukemic microenvironment.

Taurine ameliorates radiation-induced oxidative stress in bone marrow mesenchymal stromal cells and promotes osteogenesis

Osteoradionecrosis of the jaw (ORNJ) is a severe complication following head and neck radiotherapy that significantly impacts the quality of life of patients. Currently, there is a lack of comprehensive understanding of the microenvironmental factors involved in ORNJ. In this study, we reveal the activation of taurine metabolism in irradiated mandibular stromal cells using scRNA-Seq and demonstrate a decrease in taurine levels in irradiated bone marrow mesenchymal stromal cells (BMSCs) through metabolomics. Compared with unirradiated BMSCs, taurine uptake in irradiated BMSCs increases. Taurine concentrations in the peripheral blood and jaws of irradiated mice are significantly lower than those in unirradiated mice (P = 0.0064 and 0.0249 respectively). Supplementation with taurine promotes osteogenic differentiation, reduces oxidative stress, and decreases DNA damage in irradiated BMSCs. Oral administration of taurine significantly improves the survival rate of irradiated mice and enhances osteogenesis in irradiated jaws. Our study highlights the role of taurine in the recovery from radiation-induced jaw injury, and suggests its potential as a non-invasive therapeutic option for combating ORNJ.

Impact of Bone Metastasis in Stage IV Non–Small Cell Lung Cancer Treated With Durvalumab and Tremelimumab With or Without Chemotherapy: A Retrospective Analysis of the CCTG BR.34 Trial

PURPOSE This retrospective analysis examines the impact of bone metastasis on outcomes in patients with non–small cell lung cancer (NSCLC) from the CCTG BR.34 trial, which investigated the combined immune checkpoint blockade. MATERIALS AND METHODS The CCTG BR.34 trial was a randomized phase II study assessing durvalumab plus tremelimumab, with or without platinum-doublet chemotherapy, in 301 patients with metastatic NSCLC. Patients were categorized into two cohorts on the basis of bone metastasis: cohort A (n = 129) and cohort B (n = 172). The primary end point was overall survival (OS), analyzed using Cox regression and multivariable models. RESULTS Patients with bone metastasis had notably poorer outcomes. The median OS was 10.9 months for those with bone metastasis versus 18.7 months for those without (hazard ratio [HR] 1.68, P = .001). The median progression-free survival (PFS) was 3.4 months with bone metastasis compared with 7.2 months without (HR, 1.82, P < .0001). The overall response rate (ORR) was lower in patients with bone metastasis (29.5%) compared with those without (45.9%; odds ratio [OR], 0.52, P = .01). Adding chemotherapy to durvalumab plus tremelimumab did not significantly affect OS ( P = .23), PFS ( P = .84), or ORR ( P = .25) in relation to bone metastasis. Multivariable analysis reaffirmed that bone metastasis was linked to decreased OS (HR, 1.42, P = .036), PFS (HR, 1.69, P < .0001), and ORR (OR, 0.52, P = .01). CONCLUSION Bone metastasis was associated with worse outcomes in this dual immune checkpoint blockade trial, with or without chemotherapy. Future trials should consider bone metastasis as a stratification factor and explore combining immune checkpoint inhibitors with targeted therapies addressing bone microenvironment factors (eg, interleukin-8, PTHrP, and transforming growth factor-β).

Oxygen-Bonded Amorphous Transition Metal Dichalcogenides with pH-Responsive Reactive Oxygen Biocatalysis for Combined Antibacterial and Anti-inflammatory Therapies in Diabetic Wound Healing.

Diabetic wound healing is a formidable challenge, often complicated by biofilms, immune dysregulation, and hindered vascularization within the wound environments. The intricate interplay of these microenvironmental factors has been a significant oversight in the evolution of therapeutic strategies. Herein, the design of an efficient and versatile oxygen-bonded amorphous transition metal dichalcogenide biocatalyst (aRuS-Or) with pH-responsive reactive oxygen biocatalysis for combined antibacterial and anti-inflammatory therapies in promoting diabetic wound healing is reported. Leveraging the incorporation of Ru─O bonds, aRuS-Or exhibits optimized adsorption/desorption behavior of oxygen intermediates, thereby enhancing both the reactive oxygen species (ROS) generation activity in acidic conditions and ROS scavenging performance in neutral environments. Remarkably, aRuS-Or demonstrates exceptional bactericidal potency within infected milieus through biocatalytic ROS generation. Beyond its antimicrobial capability, post-eradication, aRuS-Or serves a dual role in mitigating oxidative stress in inflammatory wounds, providing robust cellular protection and fostering an M2-phenotype polarization of macrophages, which is pivotal for accelerating the wound repair process. The findings underscore the multifaceted efficacy of aRuS-Or, which harmoniously integrates high antibacterial action with anti-inflammatory and pro-angiogenic properties. This triad of functionalities positions aRuS-Or as a promising candidate for the comprehensive management of complex diabetic ulcers, addressing the unmet needs in the current therapeutics.

Factors associated with low resilience among French university students during COVID-19 lockdown

Abstract Background COVID-19 and subsequent lockdowns had an impact on the mental health of students, who had already been identified as a vulnerable population prior to this pandemic. At the end of the first COVID-19 lockdown, 15% of students reported suffering from moderate to severe anxiety. Psychological resilience is defined as the ability to bounce back from a stressful event and has been shown to have a positive impact on mental health parameters. This study aimed to identify factors associated with low resilience in the student population of the Grand Est region of France, at the end of the first national containment related to COVID-19. Methods The PIMS-CoV19 study: A cross-sectional online survey was conducted among students at the University of Lorraine to collect sociodemographic data, living and learning conditions, as well as levels of resilience and perceived health. Bivariable and multivariable logistic regression analyses were performed. Model robustness was assessed using bootstrap resampling. Results Among 3708 students, 50.6% had normal resilience, while 37.3% reported low resilience. Female gender (OR = 2.1, 95% CI: 1.8-2.6) and low social support (OR = 1.7, 95% CI: 1.1-2.6) were the main risk factors for low resilience. Negative thoughts (OR = 1.4, 95% CI: 1.4-1.5), lower quality of relationships with people in general (OR = 1.5, 95% CI: 1.3-1.8), and studying arts, humanities, or languages (OR = 1.4, 95% CI: 1.0-1.8) were identified as risk factors. Increased age (OR = 0.9, 95% CI: 0.9-1.0) and flat sharing (OR = 0.6, 95% CI: 0.4-0.9) were protective factors against low resilience. Conclusions Resilience seems to be impacted primarily by internal and micro-environmental factors. Consolidating levels of individual resilience of at-risk populations by acting on these factors could be the key to improving their mental health. Key messages • Resilience seems to be impacted primarily by internal and micro-environmental factors. • Consolidating levels of individual resilience of at-risk populations by acting on these factors could be the key to improving their mental health.

How Salt and Temperature Drive Reentrant Condensation of Aβ40.

Within the framework of liquid-liquid phase separation (LLPS), biomolecular condensation orchestrates vital cellular processes, and its dysregulation is implicated in severe pathological conditions. Recent studies highlight the role of intrinsically disordered proteins (IDPs) in LLPS, yet the influence of microenvironmental factors has remained a puzzling factor. Here, via computational simulation of the impact of solution conditions on LLPS behavior of neurologically pathogenic IDP Aβ40, we chanced upon a salt-driven reentrant condensation phenomenon, wherein Aβ40 aggregation increases with low salt concentrations (25-50 mM), followed by a decline with further salt increments. An exploration of the thermodynamic and kinetic signatures of reentrant condensation unveils a nuanced interplay between protein electrostatics and ionic strength as potential drivers. Notably, the charged residues of the N-terminus exhibit a nonmonotonic response to salt screening, intricately linked to the recurrence of reentrant behavior in hydrophobic core-induced condensation. Intriguingly, our findings also unveil the reappearance of similar reentrant condensation phenomena under varying temperature conditions. Collectively, our study illuminates the profoundly context-dependent nature of Aβ40s liquid-liquid phase separation behavior, extending beyond its intrinsic molecular framework, where microenvironmental cues wield significant influence over its aberrant functionality.

AMBER: A Modular Model for Tumor Growth, Vasculature and Radiation Response.

Computational models of tumor growth are valuable for simulating the dynamics of cancer progression and treatment responses. In particular, agent-based models (ABMs) tracking individual agents and their interactions are useful for their flexibility and ability to model complex behaviors. However, ABMs have often been confined to small domains or, when scaled up, have neglected crucial aspects like vasculature. Additionally, the integration into tumor ABMs of precise radiation dose calculations using gold-standard Monte Carlo (MC) methods, crucial in contemporary radiotherapy, has been lacking. Here, we introduce AMBER, an Agent-based fraMework for radioBiological Effects in Radiotherapy that computationally models tumor growth and radiation responses. AMBER is based on a voxelized geometry, enabling realistic simulations at relevant pre-clinical scales by tracking temporally discrete states stepwise. Its hybrid approach, combining traditional ABM techniques with continuous spatiotemporal fields of key microenvironmental factors such as oxygen and vascular endothelial growth factor, facilitates the generation of realistic tortuous vascular trees. Moreover, AMBER is integrated with TOPAS, an MC-based particle transport algorithm that simulates heterogeneous radiation doses. The impact of radiation on tumor dynamics considers the microenvironmental factors that alter radiosensitivity, such as oxygen availability, providing a full coupling between the biological and physical aspects. Our results show that simulations with AMBER yield accurate tumor evolution and radiation treatment outcomes, consistent with established volumetric growth laws and radiobiological understanding. Thus, AMBER emerges as a promising tool for replicating essential features of tumor growth and radiation response, offering a modular design for future expansions to incorporate specific biological traits.

Suppression of dystroglycan function accompanies pancreatic acinar-to-ductal metaplasia and favours dysplasia development.

The basement membrane (BM) is among the predominant microenvironmental factors of normal epithelia and of precancerous epithelial lesions. Evidence suggests that the BM functions not only as a barrier to tumour invasion but also as an active tumour-suppressing signalling substrate during premalignancy. However, the molecular foundations of such mechanisms have not been elucidated. Here we explore potential tumour-suppressing functions of the BM during precancer evolution, focusing on the expression and function of the extracellular matrix receptor dystroglycan in the pancreas and pancreatic disease. We show that the dystroglycan protein is highly expressed in the acinar compartment of the normal pancreas but lower in the ductal compartment. Moreover, there is a strong suppression of dystroglycan protein expression with acinar-to-ductal metaplasia in chronic pancreatitis and in all stages of pancreatic precancer and cancer evolution, from acinar-to-ductal metaplasia to dysplasia to adenocarcinoma. The conditional knockout of dystroglycan in the murine pancreas produced little evidence of developmental or functional deficiency. However, conditional deletion of dystroglycan expression in the context of oncogenic Kras expression led to a clear acceleration of pancreatic disease evolution, including accelerated dysplasia development and decreased survival. These data establish dystroglycan as a suppressor of pancreatic dysplasia development and one that is muted in chronic pancreatitis and at the earliest stages of oncogene-induced transformation. We conclude that dystroglycan is an important mediator of the tumour-suppressing functions of the BM during precancer evolution and that reduced dystroglycan function increases cancer risk, highlighting the dynamics of cell-BM interactions as important determinants of early cancer progression. © 2024 The Pathological Society of Great Britain and Ireland.

Functional traits of Epifagus virginiana (Orobanchaceae) tubers as adaptations to the Mexican beech microenvironment

Epifagus virginiana (Orobanchaceae), known as beechdrops, is a holoparasitic plant that acquires all its resources from a narrow range of host plants, restricted to North American Fagus species. To do so, beechdrops develop a vascular connection with the host via a terminal haustoria that develops as a tuber attached to the host root. We hypothesized that microenvironmental conditions can influence functional traits of the E. virginiana tuber despite this parasite's complete reliance on the host plant for its nutrition. Therefore, the aims of this study were i) to analyze the structure of the tubers of E. virginiana; ii) to assess the variation in tuber functional traits between two E. virginiana populations; and iii) to analyze how microenvironmental factors influence functional traits in the tuber. We detected that functional trait of beechdrops tuber along Mexican beech microenvironmental covaried with traits important for below-ground processes. Boosted regression trees provided a powerful analysis tool, giving substantially superior predictive performance to generalized additive models, despite the fitting of interaction terms in the latter.

Tumor-Secreted Extracellular Vesicles Counteract Therapy Response by Triggering Inflammatory Mesenchymal Stem Cell Development.

Therapy resistance is a major clinical hurdle in bone cancer treatment and seems to be largely driven by poorly understood microenvironmental factors. Recent evidence suggests a critical role for a unique subpopulation of mesenchymal stem cells with inflammatory features (iMSC), though their origin and function remained unexplored. We demonstrate that cancer-secreted extracellular vesicles (EV) trigger the development of iMSCs, which hinder therapy response in vivo, and set out to identify strategies to counteract their function. The role of iMSCs in therapy resistance was evaluated in an orthotopic xenograft mouse model of osteosarcoma. EV-induced alterations of the MSC transcriptome were analyzed and compared with single-cell RNA sequencing data of biopsies from patients with osteosarcoma and multiple myeloma. Functional assays identified EV components driving iMSC development. We assessed the efficacy of clinical drugs in blocking iMSC-induced resistance in vivo. We found that iMSCs are induced by interaction with cancer EVs and completely abrogate the antimetastatic effect of TGFβ signaling inhibition. Importantly, EV-induced iMSCs faithfully recapitulate the inflammatory single-cell RNA signature of stromal cells enriched in biopsies from patients with multiple myeloma and osteosarcoma. Mechanistically, cancer EVs act through two distinct mechanisms. EV-associated TGFβ induces IL6 production, whereas the EV-RNA cargo enhances TLR3-mediated chemokine production. We reveal that simultaneous blockade of downstream EV-activated pathways with ladarixin and tocilizumab disrupts metastasis formation and overcomes iMSC-induced resistance. Our observations establish iMSCs as major contributors to drug resistance, reveal EVs as triggers of iMSC development, and highlight a promising combination strategy to improve therapy response in patients with bone cancer.

Energy Metabolism Behavior and Response to Microenvironmental Factors of the Experimental Cancer Cell Models Differ From That of Actual Human Tumors.

Analysis of the biochemical differences in the energy metabolism among bi-dimensional (2D) and tri-dimensional (3D) cultured cancer cell models and actual human tumors was undertaken. In 2D cancer cells, the oxidative phosphorylation (OxPhos) fluxes range is 2.5-19 nmol O2/min/mg cellular protein. Hypoxia drastically decreased OxPhos flux by 2-3 times in 2D models, similar to what occurs in mature multicellular tumor spheroids (MCTS), a representative 3D cancer cell model. However, mitochondrial protein contents and enzyme activities were significantly different between both models. Moreover, glycolytic fluxes were also significantly different between 2D and MCTS. The glycolytic flux range in 2D models is 1-34 nmol lactate/min/mg cellular protein, whereas in MCTS the range of glycolysis fluxes is 60-80 nmol lactate/min/mg cellular. In addition, sensitivity to anticancer canonical and metabolic drugs was greater in MCTS than in 2D. Actual solid human tumor samples show lower (1.6-4.5 times) OxPhos fluxes compared to normoxic 2D cancer cell cultures. These observations indicate that tridimensional organization provides a unique microenvironment affecting tumor physiology, which has not been so far faithfully reproduced by the 2D environment. Thus, the analysis of the resemblances and differences among cancer cell models undertaken in the present study raises caution on the interpretation of results derived from 2D cultured cancer cells when they are extended to clinical settings. It also raises awareness about detecting which biological and environmental factors are missing in 2D and 3D cancer cell models to be able to reproduce the actual human tumor behavior.

Targeting esophageal carcinoma: molecular mechanisms and clinical studies.

Esophageal cancer (EC)is identified as a predominant health threat worldwide, with its highest incidence and mortality rates reported in China. The complex molecular mechanisms underlying EC, coupled with the differential incidence of esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) across various regions, highlight the necessity for in-depth research targeting molecular pathogenesis and innovative treatment strategies. Despite recent progress in targeted therapy and immunotherapy, challenges such as drug resistance and the lack of effective biomarkers for patient selection persist, impeding the optimization of therapeutic outcomes. Our review delves into the molecular pathology of EC, emphasizing genetic and epigenetic alterations, aberrant signaling pathways, tumor microenvironment factors, and the mechanisms of metastasis and immune evasion. We further scrutinize the current landscape of targeted therapies, including the roles of EGFR, HER2, and VEGFR, alongside the transformative impact of ICIs. The discussion extends to evaluating combination therapies, spotlighting the synergy between targeted and immune-mediated treatments, and introduces the burgeoning domain of antibody-drug conjugates, bispecific antibodies, and multitarget-directed ligands. This review lies in its holistic synthesis of EC's molecular underpinnings and therapeutic interventions, fused with an outlook on future directions including overcoming resistance mechanisms, biomarker discovery, and the potential of novel drug formulations.

Embryonic macrophages support endocrine commitment during human pancreatic differentiation

Organogenesis is a complex process that relies on a dynamic interplay between extrinsic factors originating from the microenvironment and tissue-specific intrinsic factors. For pancreatic endocrine cells, the local niche consists of acinar and ductal cells as well as neuronal, immune, endothelial, and stromal cells. Hematopoietic cells have been detected in human pancreas as early as 6 post-conception weeks, but whether they play a role during human endocrinogenesis remains unknown. To investigate this, we performed single-nucleus RNA sequencing (snRNA-seq) of the second-trimester human pancreas and identified a wide range of hematopoietic cells, including two distinct subsets of tissue-resident macrophages. Leveraging this discovery, we developed a co-culture system of human embryonic stem cell-derived endocrine-macrophage organoids to model their interaction invitro. Here, we show that macrophages support the differentiation and viability of endocrine cells invitro and enhance tissue engraftment, highlighting their potential role in tissue engineering strategies for diabetes.