Project description:Hepatoblastoma remains one of the most difficult childhood tumors to treat and is alarmingly understudied. Over half of patients initially present with locally advanced or metastatic disease and the prognosis for this cohort remains dismal. In addition, many of these children have disease that is resistant to standard therapies and will require novel and targeted therapies to effectively treat or manage their disease. We previously demonstrated that Proviral Insertion site in Maloney murine leukemia virus (PIM) kinases, specifically PIM3, are overexpressed in human hepatoblastoma cells and function to promote tumorigenesis. We aimed to use CRISPR/Cas9 gene editing technology with dual gRNAs to introduce large inactivating deletions in the PIM3 gene and achieve stable PIM3 knockout (KO) in the human hepatoblastoma cell line, HuH6. PIM3 KO of hepatoblastoma cells led to significantly decreased proliferation, viability, and motility, inhibited cell-cycle progression, decreased tumor growth in a xenograft murine model, and increased animal survival. Analysis of RNA sequencing data revealed that PIM3 KO downregulated expression of pro-migratory and pro-invasive genes and upregulated expression of genes involved in apoptosis and differentiation. Furthermore, PIM3 KO decreased hepatoblastoma cancer cell stemness as evidenced by decreased tumorsphere formation, decreased mRNA abundance of stemness markers, and decreased cell surface expression of CD133, a marker of hepatoblastoma stem cell-like cancer cells. Reintroduction of PIM3 into PIM3 KO cells rescued the malignant phenotype. These findings emphasize the role of PIM3 in promoting hepatoblastoma tumorigenesis and provide evidence that targeting PIM3 may offer a novel therapeutic approach for children with hepatoblastoma.
Project description:Lack of relevant disease animal models and cell lines hampers our understanding of hepatoblastoma and identification of therapeutic targets. We report a liver-specific MYC-driven hepatoblastoma murine model that faithfully recapitulates the pathological features of mixed fetal and embryonic hepatoblastoma, with transcriptomics resembling the high-risk gene signatures of human disease. Single-cell RNA-sequencing (scRNA-seq) and spatiotranscriptomics identify a subpopulation of hepatoblastoma cells with high levels of adult hemoglobin genes. After deriving a cell line from the mouse model, we mapped the cancer dependency genes using CRISPR-Cas9 and identified druggable targets shared with human hepatoblastoma (i.e., CDK7, CDK9, PRMT1, PRMT5). Our screen also discovered oncogenes and tumor suppressive genes in hepatoblastoma that engage multiple cancer signaling pathways. Chemotherapy is the mainstay of human hepatoblastoma. Genetic map of doxorubicin response by CRISPR-Cas9 identified modifiers whose loss-of-function synergizes (PRKDC) and antagonizes (Polycomb repressive complex 2) the effect of chemotherapy. Combination of PRKDC inhibitor and chemotherapy greatly enhances therapeutic efficacy. Our studies have provided useful disease models and potential therapeutic targets of hepatoblastoma.
Project description:Background & Aims: Extracellular vesicles (EVs) play a pivotal role in connecting tumor cells and their local and distant microenvironment. Here, we aimed to understand the role and molecular basis of patient-derived EVs in modulating cancer stemness and tumorigenesis in the context of hepatocellular carcinoma (HCC). Methods: EVs were isolated, quantified and characterized from patients’ sera. EVs were tested vigorously, both in vitro and in vivo, by various functional assays. Proteomic analysis was performed to identify the functional components of EVs. The expression level of polymeric immunoglobulin receptor (pIgR) in circulating EVs, tumor and non-tumorous tissues of HCC patients was determined by ELISA, immunoblotting, immunohistochemistry and quantitative PCR. The functional role and underlying mechanism of EVs with an enhanced pIgR expression was elucidated. Blockage of EV-pIgR with neutralizing antibody was performed in nude mice implanted with patient-derived tumor xenograft (PDTX). Results: Circulating EVs of late-stage HCC (L-HCC) patient had significantly elevated pIgR expression when compared to the EVs released by control individuals. The augmenting effect of L-HCC patient in cancer stemness and tumorigenesis was hindered by anti-pIgR antibody. EVs enriched with pIgR consistently promoted cancer stemness and cancerous phenotypes in the recipient cells. Mechanistically, EV-pIgR-induced cancer aggressiveness was abrogated by Akt and β-catenin inhibitors, ascertaining the role of EV-pIgR through the activation of PDK1/Akt/GSK3β/β-catenin signaling axis. Furthermore, anti-pIgR neutralizing antibody attenuated the tumor growth in mice implanted with PDTX. Conclusion: The study illustrates an unrevealed role of EV-pIgR in regulating cancer stemness and aggressiveness, in which EV-pIgR activates PDK1/Akt/GSK3β/β-catenin signaling cascades. The blockage of intercellular communications mediated by EV-pIgR in the tumor microenvironment may provide a new therapeutic strategy for cancer patients.
Project description:We identify a new mechanism by which OLZ ameliorates chronic stress-enhanced tumorigenesis and chemoresistance. OLZ reversed chronic stress-enhanced lung tumorigenesis and anxiety-like behaviors by suppressing neuro-activity in the mPFC and reducing norepinephrine (NE) releasing. To investigate the mechanism of NE in cancer stemness we performed RNA-seq of the NCI-H1299 cells under NE treatment and found that NE activated β2-adrenoceptor (ADRB2)-mediated cAMP-PKA-CREB pathway to transactivate CLOCK that further sustains cancer stemness.
Project description:The Notch signaling pathway regulates fate decision, proliferation and differentiation of intestinal epithelial cells. However, the role of Notch signaling in colorectal cancer progression is largely unknown. Here we show that Notch signaling suppresses the progression of colorectal tumorigenesis, even though it augments tumor initiation. In contrast to adenomas of Apcmin mice, Notch-inactivated Apcmin adenomas showed more malignant characteristics, such as submucosal invasion and loss of glandular pattern. Conversely, Notch-activated Apcmin adenomas showed a reversion from high-grade to low-grade features, such as the restoration of adherent junctions. Expression profiling revealed that Notch signaling promotes the differentiation of tumor cells with down regulation of Wnt/beta-catenin target genes and inhibition of epithelial-mesenchymal transition. Comparison of mouse and human expression profiles also suggests the common role of Notch in inhibition of tumor progression. Interestingly, Notch signaling suppressed the expression of beta-catenin responsive genes through chromatin modification of Tcf4/beta-catenin binding sides. Our results suggest that Notch signaling has dual roles in colorectal tumorigenesis: promoting adenoma initiation, while inhibiting tumor progression to colorectal cancer. mRNAs from normal (WT, Notch-activated and Notch-inactivated) and tumor (WT, Notch-activated and Notch-inactivated) tissues were profiled.
Project description:The mechanisms underlying hepatoblastoma are not well defined. To address this, we generated transcriptomic profiles of normal, background, and hepatoblastoma liver samples from patients aged 0.01 months to 6 years, using RNA-sequencing. Hepatoblasoma was histologically confirmed. Here we focus on the elevation of stem cell markers and the loss of tumor suppressor proteins leading to the development of hepatoblastoma in very young children.