Biology subjects

Giannikou, K.

Publications and source records attributed to Giannikou, K..

4 recordsLinked to original sources

bioRxiv2025

Integrated single-nuclei and spatial transcriptomic profiling of human sacrococcygeal teratomas reveals heterogeneity in cellular composition and X-chromosome inactivation

Sacrococcygeal teratomas (SCTs) are the most common neonatal tumors, yet their cellular origins, clinical stratification, and sex bias-occurring three times more in XX than XY individuals--remain poorly understood. To address these gaps, we examined six postnatal (one male and five female) and two prenatal (both female) SCTs by single nuclei RNA-seq and spatial transcriptomics. We identified five broad cellular lineages in SCTs: stroma, epithelia, endothelia, neuroectoderm, and immune. The transcriptomes and lineage compositions showed significant heterogeneity, which offer a framework for future molecular stratification. SCTs are thought to originate from and be propagated by pluripotent cells, notably however, we did not detect these populations. Among female tumors, a subset of cells exhibited biallelic expression of X-linked genes, consistent with X-inactivation failure or reactivation of the once inactivated X-chromosome. These biallelic cells were enriched for developmental and neuronal programs, whereas cells with single-allelic X-chromosome preferentially expressed immune-related genes. Biallelic X-chromosome activation, which can occur only in female cells, may result in transcriptomic features that favor survival of tumor cells, contributing to the sex bias of SCTs. Our findings reveal a link between X-chromosome inactivation and SCT cell identity, suggesting that X-dosage dysregulation may influence SCT heterogeneity and immune landscape.

cancer biology↗

bioRxiv2025

Tumor-associated stroma shapes the spatial tumor immune microenvironment of primary Ewing sarcomas

To date, few studies have detailed the tumor microenvironment (TME) of Ewing sarcoma (EwS). The TME has a vital role in cancer survival and progression with implications in drug resistance and immune escape. By performing spatially resolved transcriptomic analysis of primary treatment-naive EwS samples, we discovered greater stromal enrichment in localized EwS tumors compared to metastatic EwS tumors. Through spatial ligand-receptor analysis, we show that the stromal enriched regions harbor unique extracellular matrix related cytokines, immune recruitment and proinflammatory microenvironmental signals, implying EwS stroma may play an anti-tumorigenic role by acting as an immune recruitment center. All EwS tumors expressed pro-tumorigenic MIF-CD74 immune signaling, suggesting a potential immune-evasive mechanism and immunotherapy target. Our findings provide insight into tumor cell/stromal cell interactions in EwS and serve as a valuable resource for further investigations in the tumor immune microenvironment of EwS.

cancer biology↗

bioRxiv2021

A Tissue-Bioengineering Strategy for Modeling Rare Human Kidney Diseases In Vivo

The lack of animal models for certain human diseases precludes our understanding of disease mechanisms and our ability to test new therapies in vivo. Here we generated kidney organoids from Tuberous Sclerosis Complex (TSC) patient-derived-hiPSCs to recapitulate a rare kidney tumor called angiomylipoma (AML). Organoids derived from TSC2-/- hiPSCs but not from isogenic TSC2+/- or TSC2+/+ hiPSCs shared a common transcriptional signature and a myomelanocytic cell phenotype with kidney AMLs, and developed epithelial cysts, replicating two major TSC-associated kidney lesions driven by genetic mechanisms that cannot be robustly and consistently recapitulated with transgenic mice. Transplantation of multiple TSC2-/- kidney organoids into the kidneys of immunodeficient rats allowed us to recapitulate AML and cystic kidney disease in vivo, in a scalable fashion and with fidelity, and to test the efficiency of rapamycin-loaded nanoparticles as a novel approach to ablate AMLs by inducing apoptosis triggered by mTOR-inhibition. Collectively, these methods represent a novel tissue-bioengineering strategy for rare disease modeling in vivo.

bioengineering↗

bioRxiv2019

Identification of the lymphangioleiomyomatosis cell and its uterine origin

Lymphangioleiomyomatosis (LAM) is a metastasizing neoplasm of reproductive age women that causes cystic lung remodeling and progressive respiratory failure. The source of LAM cells that invade the lung and the reasons that LAM targets women have remained elusive. We employed single cell and single nuclei RNA sequencing on LAM lesions within explanted LAM lungs, known to contain smooth muscle like cells bearing mTOR activating mutations in TSC1 or TSC2, and identified a unique population of cells that were readily distinguished from those of endogenous lung cells. LAMCORE cells shared closest transcriptomic similarity to normal uterus and neural crest. Immunofluorescence microscopy demonstrated the expression of LAMCORE cell signature genes within LAM lesions in both lung and uterus. Serum aptamer proteomics and ELISA identified biomarkers predicted to be secreted by LAMCORE cells. Single cell transcriptomics strongly supports a uterine neural crest origin of LAMCORE cells; providing insights into disease pathogenesis and informing future treatment strategies for LAM.\n\nSIGNIFICANCEPresent study identified a novel population of LAMCORE cells, which is likely originated from uterine neural crest; identified novel LAM cell-specific secretome proteins that hold promise as potential biomarkers and therapeutic targets. Advancing the understanding of LAM pathogenesis and metastasis model may yield broader insights into the biology of cancer.

cancer biology↗