Project description:Intra-tumor heterogeneity of tumor-initiating cell (TIC) activity drives colorectal cancer (CRC) progression and therapy resistance. Here, we used single-cell mRNA-sequencing (scRNA-seq) of patient-derived CRC models to decipher distinct cell subpopulations based on their transcriptional profiles. Cell type-specific expression modules of stem-like, transit amplifying-like, and differentiated CRC cells resemble differentiation states of normal intestinal epithelial cells. Strikingly, identified subpopulations differ in proliferative activity and metabolic state. In summary, we here show at single-cell resolution that transcriptional heterogeneity identifies functional states during TIC differentiation. Targeting transcriptional states associated to cancer cell differentiation might unravel vulnerabilities in human CRC.
Project description:Brain metastasis (BrM) represents the most common and aggressive brain malignancy, predominantly arising from non-small cell lung cancer, breast cancer, and melanoma. Recent studies have revealed the importance of the brain tumor microenvironment (TME), notably diverse immune cells, which play important roles in regulating cancer progression in both primary and metastatic brain malignancies. The blood-brain barrier (BBB) is another critical TME component formed by endothelial cells, mural cells, astrocytic end-feet, and closely-associated microglial cells. Metastasizing cancer cells can utilize different strategies to traverse the BBB and once they have successfully seeded and colonized the brain, they can exploit the vasculature for their own benefit, forming the blood-tumor barrier. To explore the mechanisms underlying tumor vascularization in brain metastasis we performed a comprehensive multiomic analysis of the key components of the tumor vasculature. We integrated single-cell and/or bulk RNA sequencing of sorted endothelial and mural cells isolated from human and mouse BrM and non-tumor samples; immunofluorescence imaging analysis of the spatial architecture of the TME; and functional studies using BrM mouse models to target vascular regulators of tumor immunity. Our results provide a comprehensive understanding of the biology underlying vascularization in metastatic brain tumors, specifically highlighting the importance of vascular cells as immune regulators and proposing novel therapeutic strategies for these aggressive tumors.
Project description:The glioblastoma (GBM) microenvironment contains resident immune cells with intrinsic anti-tumor potential, particularly microglia. Understanding the single-cell spatial heterogeneity and interactions between immune cells and brain tumor–initiating cells (BTICs) is essential for identifying therapeutic targets to reprogram immune responses and suppress BTIC growth. Using single-cell and spatial transcriptomics, we mapped immune cell populations in the GBM microenvironment and identified signaling networks mediating immune–cancer cell interactions. We discovered a previously unrecognized subset of microglia expressing protein kinase Cδ (PKCδ) with anti-tumor activity against BTICs. The presence of PKCδ-expressing microglia was validated in human GBM specimens. Enhancing PKCδ in microglia via adeno-associated virus or niacin increased phagocytosis of patient-derived BTICs in vitro and improved survival in GBM-bearing mice. Data from The Cancer Genome Atlas (TCGA) revealed that high PKCδ expression correlates with increased apoptosis, phagocytosis, and immune signaling pathways. These findings offer highlight PKCδ+ microglia as a promising therapeutic target in GBM.
Project description:The glioblastoma (GBM) microenvironment contains resident immune cells with intrinsic anti-tumor potential, particularly microglia. Understanding the single-cell spatial heterogeneity and interactions between immune cells and brain tumor–initiating cells (BTICs) is essential for identifying therapeutic targets to reprogram immune responses and suppress BTIC growth. Using single-cell and spatial transcriptomics, we mapped immune cell populations in the GBM microenvironment and identified signaling networks mediating immune–cancer cell interactions. We discovered a previously unrecognized subset of microglia expressing protein kinase Cδ (PKCδ) with anti-tumor activity against BTICs. The presence of PKCδ-expressing microglia was validated in human GBM specimens. Enhancing PKCδ in microglia via adeno-associated virus or niacin increased phagocytosis of patient-derived BTICs in vitro and improved survival in GBM-bearing mice. Data from The Cancer Genome Atlas (TCGA) revealed that high PKCδ expression correlates with increased apoptosis, phagocytosis, and immune signaling pathways. These findings offer highlight PKCδ+ microglia as a promising therapeutic target in GBM.
Project description:The majority of meningiomas are benign tumors associated with favorable outcomes; however, the less common aggressive variants with unfavorable outcomes often recur and may be due to sub-populations of less-differentiated cells residing within the tumor. These sub-populations of tumor cells, termed tumor-initiating cells, may be isolated from heterogeneous tumors when sorted or cultured in defined medium designed for enrichment of the tumor-initiating cells. We report the isolation and characterization of a population of tumor-initiating cells derived from an atypical meningioma. These meningioma-initiating cells (MICs) self-renew, differentiate, and can recapitulate the histological characteristics of the parental tumor when transplanted into athymic nude mice. Immunohistochemistry reveals protein expression patterns similar to neural stem and progenitor cells while genomic profiling verified the isolation of cancer cells (with defined meningioma chromosomal aberrations) from the bulk tumor. Furthermore, microarray analysis of gene expression reveals that many epithelial to mesenchymal transition genes are upregulated in the MICs, consistent with the presence of both neural stem cell and mature neural cell molecular markers seen in the derived cultures. Pathway analysis identifies biochemical processes and gene networks related to aberrant cell cycle progression, particularly the loss of heterozygosity of tumor suppressor genes CDKN2A (p16INK4A), p14ARF, and CDKN2B (p15INK4B). Flow cytometric analysis revealed the expression of CD44 and activated leukocyte adhesion molecule (ALCAM/CD166); these may prove to be markers able to identify this cell type. In conclusion, we identify a tumor-initiating population from an atypical meningioma that displays a unique phenotype and these results provide increased understanding of atypical meningioma progression. Part 1 of 2: Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from primary tissue and their counterpart cell lines Part 2 of 2: Illumina gene expression array analysis was performed according to the manufacturer's directions on RNA extracted from cultured primary Meningioma and neural stem cell lines