Biology subjects

Fernandez-Zapico, M. E.

Publications and source records attributed to Fernandez-Zapico, M. E..

10 recordsLinked to original sources

bioRxiv2025

Longitudinal Analysis of Matched Patient Biospecimens Reveals Neural Reprogramming of Cancer-Associated Fibroblasts Following Chemotherapy in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC), the most common subtype of pancreatic cancer, is a deadly disease with a complex tumor microenvironment (TME). How chemotherapy alters the TME, and whether these changes drive chemoresistance, is poorly understood. We examined matched pre- and post-treatment tissue specimens and found near-universal enrichment of axonal guidance genes in cancer-associated fibroblasts (CAFs) after treatment. These CAFs were enriched near sites of perineural invasion, coinciding with regions of increased tumor cell proliferation, and were enriched in tumor areas distant from nerves after chemotherapy. Metastatic recurrence lesions had the highest prevalence of these CAFs versus primary tumors and untreated metastasis. These CAFs showed elevated non-canonical Wnt mediators and axonal guidance genes, which complemented matching cognate binding partners in tumor epithelial cells, suggesting a role in tumor-stroma crosstalk. Our findings implicate fibroblast-derived axonal-guidance genes in promoting PDAC invasion and point to a promising target for this disease. Statement of SignificanceTherapeutic resistance remains a major challenge in pancreatic cancer. Our findings shed light on the changes in the complex tumor microenvironment in response to chemotherapy and identify fibroblasts high in axonal-guidance genes that may drive tumor progression and chemoresistance, thus uncovering a potential avenue for targeting pancreatic cancer.

cancer biology↗

bioRxiv2025

Spatial Conformation of Pancreatic Cancer Is Associated with Disease Recurrence after Curative-Intent Total Neoadjuvant Therapy

Pancreatic ductal adenocarcinoma (PDAC) frequently recurs after total neoadjuvant therapy (TNT) and curative-intent resection. Traditional histopathologic response assessments demonstrate that major pathologic response (<5-10% viable residual cancer) is associated with favorable outcomes. However, most TNT cases achieve only a minor response. We investigated whether the spatial organization of residual PDAC encodes clinically meaningful biology beyond residual tumor burden. In a retrospective cohort of 203 resected PDAC patients, all with minor pathologic response, H&E whole-slide images were segmented into cancer and stroma to subsequently quantify spatial composition (e.g., patch size/density, edge density) and configuration (e.g., patch complexity/compactness, spatial intermixing) to model treatment-resistant tumor architecture. Non-response was associated with a more fragmented interface-rich ecology, higher edge density and diversity, and reduced homotypic aggregation, independent of conventional clinicopathologic features. This demonstrates a link between emergent tissue architecture of treated PDAC and therapeutic resistance. Further, two multivariable, spatial risk models were independently associated with disease-free survival (DFS): (1) cancer mean shape index and stromal shape-index variability (high-risk median DFS 7.23 vs 11.57 months; adjusted HR 1.75, p=0.007) and (2) mean stromal area with edge density (high- vs low-risk adjusted HR 1.94, p=0.006), outperforming traditional treatment response assessments. Quantifying residual cancer-stroma topology thus yields independent, prognostic signals in post-TNT PDAC and motivates prospective, spatially informed adjuvant strategies and mechanistic studies of edge habitats and mixing as therapeutic vulnerabilities.

cancer biology↗

bioRxiv2025

Pancreatic tumor microenvironment reprogramming via alloantigen-expressing virotherapy elicits tumor rejection and improves immunotherapy response

Pancreatic ductal adenocarcinoma (PDAC), the most common malignant type of pancreatic cancer, is characterized by a dense desmoplastic stroma, low neoantigen burden, and a highly immunosuppressive tumor microenvironment (TME), which severely limit cytotoxic T-cell infiltration and the efficacy of immune therapies. Here, we present a novel strategy harnessing acute transplant rejection mechanisms by employing a recombinant oncolytic rVMG vector engineered to express the murine H-2Kk MHC class I alloantigen (rVMG-H-2Kk), thereby inducing tumor-specific antigenic mismatch responses. In vitro, rVMG-H-2Kk exhibited strong replication and cytolytic activity while inducing cell surface expression of both H-2Kk and endogenous H-2Kb, in addition to upregulation of antigen presentation genes ({beta}2-microglobulin, Tap1, and Tapbp). In two independent immunocompetent PDAC models, intratumoral and systemic delivery of rVMG-H-2Kk delayed tumor progression and prolonged survival. Multiplex immunohistochemistry and immunophenotyping revealed substantial TME remodeling, marked by increased effector T-cell infiltration, regulatory T-cell depletion, and reduced fibrosis. Spatial transcriptomics further showed compartment-specific immune activation and epithelial metabolic reprogramming, corroborating with enhanced tumor immunogenicity. Despite these effects, rVMG-H-2Kk also induced compensatory immunosuppressive pathways, including upregulation of antiviral response genes and immune checkpoint receptors such as PDL-2. Importantly, combination therapy with rVMG-H-2Kk and murine checkpoint blockade (anti-PD-1 and anti-CTLA-4) drastically improved survival than checkpoint blockade alone. Strikingly, surviving mice resisted tumor rechallenge, indicating the establishment of durable antitumor memory. Collectively, these findings establish rVMG-H-2Kk as a novel immunotherapeutic platform capable of converting immune-cold tumors into immune-hot, sensitizing tumors to immune checkpoint inhibitors, and establishing durable antitumor immunity in PDAC. One Sentence SummaryOncolytic virus-based delivery of an alloantigen improves antitumor immunity and synergizes with immune checkpoint inhibitors in pancreatic cancer. Significance statementDelivery of murine alloantigens via an engineered oncolytic vesiculovirus, combined with immune checkpoint blockade, overcomes immunosuppressive barriers and establishes durable antitumor immunity in PDAC.

cancer biology↗

bioRxiv2025

Tumor Landscape Analysis: An Ecologically Informed Framework to Understand Tumor Microenvironments

Tumor microenvironments (TMEs) are spatially complex and dynamic systems shaped by evolutionary pressures, tissue architecture, and cellular interactions. To capture this complexity, we developed the Tumor Landscape Analysis (TLA) pipeline, a computational framework applying principles from landscape ecology and spatial statistics to quantitatively characterize tumor spatial heterogeneity. TLA integrates spatially resolved pathology data, including whole-cell, point-based, and region-level formats, and computes multiscale metrics to assess cell distributions, neighborhood relationships, and tissue-level organization. The framework leverages ecological indices such as the Morisita-Horn index, Ripleys H function, and Shannon diversity to quantify intercellular proximity, spatial clustering, and cellular diversity. It also uses the concept of local microenvironments (LMEs), data-driven ecological niches defined by local cell-type abundance and spatial uniformity, enabling unsupervised and reproducible classification of tumor regions. The use of fragmentation metrics, including patch density, shape complexity, and interspersion, provide further insight into spatial disorganization and emergent tissue architecture. TLA is agnostic to imaging modality and biological context, supporting broad applicability across tumor types and sample formats. By translating complex tissue architectures into interpretable spatial metrics, the pipeline enables integrative analyses that link spatial ecology to clinical and molecular phenotypes. This approach facilitates a deeper understanding of how spatial features contribute to tumor progression, therapeutic resistance, and clinical outcomes, offering new opportunities for precision oncology rooted in spatial systems biology.

cancer biology↗

bioRxiv2023

Tumor Explants Elucidate a Cascade of Paracrine SHH, WNT, and VEGF Signals Driving Pancreatic Cancer Angiosuppression

The sparse vascularity of Pancreatic Ductal Adenocarcinoma (PDAC) presents a mystery: what prevents this aggressive malignancy from undergoing neoangiogenesis to counteract hypoxia and better support growth? An incidental finding from prior work on paracrine communication between malignant PDAC cells and fibroblasts revealed that inhibition of the Hedgehog (HH) pathway partially relieved angiosuppression, increasing tumor vascularity through unknown mechanisms. Initial efforts to study this phenotype were hindered by difficulties replicating the complex interactions of multiple cell types in vitro. Here we identify a cascade of paracrine signals between multiple cell types that act sequentially to suppress angiogenesis in PDAC. Malignant epithelial cells promote HH signaling in fibroblasts, leading to inhibition of WNT signaling in fibroblasts and epithelial cells, thereby limiting VEGFR2-dependent activation of endothelial hypersprouting. This cascade was elucidated using human and murine PDAC explant models, which effectively retain the complex cellular interactions of native tumor tissues.

cancer biology↗

bioRxiv2022

Targeting BET Proteins downregulates miR-33a to promote synergy with PIM inhibitors in CMML

Preclinical studies in myeloid neoplasms have demonstrated efficacy of Bromodomain and Extra-Terminal protein inhibitors (BETi). However, BETi demonstrate poor single agent activity in clinical trials. Several studies suggest that combination with other anti-cancer inhibitors may enhance the efficacy of BETi. To nominate BETi combination therapies for myeloid neoplasms, we used a chemical screen with therapies currently in clinical cancer development. We identified PIM inhibitors (PIMi) as therapeutically synergistic with BETi in myeloid leukemia models. Mechanistically, we show that PIM kinase is increased after BETi treatment, and that PIM kinase upregulation is sufficient to induce resistance to BETi and sensitize cells to PIMi. Further, we demonstrate that miR-33a downregulation is the underlying mechanism driving PIM1 upregulation. We also show that GM-CSF hypersensitivity, a hallmark of chronic myelomonocytic leukemia (CMML), represents a molecular signature for sensitivity to combination therapy and credential this using patient-derived xenografts supporting the clinical investigation of this combination.

cancer biology↗

bioRxiv2022

The translational role of SOS1 in colorectal cancer

BackgroundIt has been challenging to develop agents directly targeting KRAS driver mutations in colorectal cancer (CRC). Recent efforts have focused on developing inhibitors targeting SOS1 as an attractive approach for KRAS-mutant cancers. Here, we aimed to study the translational role of SOS1 in CRC using patient-derived organoids (PDOs). MethodIn this study, we used CRC PDOs as preclinical models to evaluate their sensitivity to SOS1 inhibitor BI3406 and its cellular effects. We utilized large CRC datasets including GENIE cohort, TCGA PanCancer Atlas, and CPTAC-2 cohort to study the significance of molecular alterations of SOS1 in CRC. To identify potential predictive markers, we performed immunohistochemistry (IHC) on CRC tissue for SOS1/2 protein expression and RNA sequencing to identify discriminative gene sets for sensitivity to SOS1 inhibition. The findings were validated by DepMap data for SOS1 dependency. ResultCRC PDOs instead of cell lines had differential sensitivities to BI3406. There was a significant correlation between SOS1 and SOS2 mRNA expressions (Spearmans {rho} 0.56, p<0.001). SOS1/2 protein expression by IHC were universal with heterogeneous patterns in cancer cells but only minimal to none in surrounding non-malignant cells. SOS1 protein expression was associated with worse overall survival in patients with RAS/RAF mutant CRC (p=0.04). We also found that SOS1/SOS2 protein expression ratio > 1 by IHC (p=0.03) instead of KRAS mutation (p=1) was a better predictive marker to BI3406 sensitivity of CRC PDOs. This was concordant with the significant correlation between SOS1/SOS2 protein expression ratio by mass spectrometry and SOS1 dependency score. RNA-seq and gene set enrichment analysis revealed differentially expressed genes and 7 enriched gene sets involving cholesterol homeostasis, epithelial mesenchymal transition, and TNF/NF{kappa}B signaling in BI3406-resistant CRC PDOs. We further discovered that GTP-bound RAS level underwent rebound at 48 hours upon treatment with BI3406 even in BI3406-sensitive PDOs with no change of KRAS effector genes downstream. Cellular adaptation mechanisms to SOS1 inhibition may involve upregulation of SOS1/2 mRNA and SOS1 protein expressions, which may be overcome by SOS1 knockdown/degradation or synergistic effect of BI3406 with trametinib. ConclusionIn summary, CRC PDOs could serve as better models for translational study of SOS1 in CRC. High SOS1 protein expression was a worse prognostic factor in CRC. High SOS1/SOS2 protein expression ratio predicted sensitivity to SOS1 inhibition and dependency. Our preclinical findings supported further clinical development of SOS1-targeting agents in CRC.

cancer biology↗

bioRxiv2021

p97/VCP induces GLI1 to control XBP1-dependent endoplasmic reticulum stress transcriptional response

Upon accumulation of improperly folded proteins in the ER, an adaptive pathway named the UPR is triggered to restore ER homeostasis. The induction of stress genes controlling ER dynamics is a condition sine qua non for an effective UPR. Although this requirement has been extensively characterized, the transcriptional mechanism underlying this process remains in part elucidated. Here, we show that p97/VCP, an AAA+ ATPase known to modulate ER stress-induced gene expression, dynamically interacts with RUVBL2 and the mSin3A-HDAC1/2 complex. Further analysis of the mechanism defined a novel interplay between the aforementioned molecules and the transcription factor USF2 to control expression of GLI1, a primary effector of Hedgehog (Hh) signaling. Under basal conditions, GLI1 is repressed by RUVBL2-mSin3A-HDAC1/2 while upon ER stress GLI1 is induced through a mechanism requiring p97/VCP-mediated extraction of the repressor complex. Further analysis showed that GLI1 cooperate with ATF6f to activate the expression of XBP1, a transcription factor regulating the expression of genes controlling cellular stress response, under ER conditions. Overall, our work demonstrates that p97/VCP orchestrates the activation of GLI1 upon ER stress in a Hh ligand-independent fashion and defines the interplay between the newly identified p97/VCP-mSin3A-HDAC1/2 complex and the transcription factor USF2 as an essential player in this process.

cancer biology↗

bioRxiv2019

RAS mutations drive proliferative chronic myelomonocytic leukemia via activation of a novel KMT2A-PLK1 axis

ABSTRACTChronic myelomonocytic leukemia (CMML) is an aggressive hematological malignancy with limited treatment options. Whole exome (WES) and targeted sequencing of several independent cohorts of CMML patients, comparing dysplastic (dCMML) to proliferative (pCMML) CMML, as well as paired chronic phase disease and acute leukemic transformation (LT), associate acquisition of oncogenic RAS pathway mutations, the most common being NRASG12D, with aggressive disease and with disease progression. Using patient derived progenitor colony assays and a NRASG12D-Vav-Cre mouse model, we further demonstrate the role of mutant RAS signaling in driving and maintaining pCMML phenotype. RNA-sequencing links RAS pathway mutations with an increased expression of genes encoding the mitotic checkpoint kinases PLK1 and WEE1. Further, we dmeoinstrated that non-mutated lysine methyltransferase KMT2A (MLL1) acts as mediator of NRAS-induced PLK1 and WEE1 expression. Finally, we demonstrate the translational value of our findings by showing that pharmacological PLK1 inhibition decreases monocytosis and hepatosplenomegaly while improving hematopoiesis in RAS mutant patient-derived xenografts. Hence, we define severe CMML as oncogenic RAS pathway-enriched malignancies, with a unique gene expression profile regulated by KMT2A, amenable to therapeutic intervention.

cancer biology↗

bioRxiv2018

Adult Canine Intestinal Derived Organoids: A Novel In Vitro System for Translational Research in Comparative Gastroenterology

BackgroundLarge animal models, such as the dog, are increasingly being used over rodent models for studying naturally occurring diseases including gastrointestinal (GI) disorders. Dogs share similar environmental, genomic, anatomical, and intestinal physiologic features with humans. To bridge the gap between currently used animal models (e.g. mouse) and humans, and expand the translational potential of the dog model, we developed a three dimensional (3D) canine GI organoid (enteroid and colonoid) system. Organoids have recently gained interest in translational research as this model system better recapitulates the physiological and molecular features of the tissue environment in comparison with two-dimensional cultures.\n\nResultsOrganoids were propagated from isolation of adult intestinal stem cells (ISC) from whole jejunal tissue as well as endoscopically obtained duodenal, ileal and colonic biopsy samples of healthy dogs and GI cases, including inflammatory bowel disease (IBD) and intestinal carcinomas. Intestinal organoids were comprehensively characterized using histology, immunohistochemistry, RNA in situ hybridization and transmission electron microscopy, and organoids mimicked the in vivo tissue environment. Physiological relevance of the enteroid system was defined using functional assays such as Optical Metabolic Imaging (OMI), the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) function assay, and Exosome-Like Vesicles (EV) uptake assay, as a basis for wider applications of this technology in basic, preclinical and translational GI research.\n\nConclusionsIn summary, our findings establish the canine GI organoid systems as a novel model to study naturally occurring intestinal diseases in dogs and humans. Furthermore, canine organoid systems will help to elucidate host-pathogen interactions contributing to GI disease pathogenesis.

cell biology↗