Project description:BCR-Abl is a driver oncogene that causes chronic myeloid leukemia and a subset of acute lymphoid leukemias. Although tyrosine kinase inhibitors provide an effective treatment for these diseases, they generally do not kill leukemic stem cells. Leukemic stem cells are cancer-initiating cells that compete with normal hematopoietic stem cells for the bone marrow niche. Using BCR-Abl as a model oncogene, we performed a drug screen based on competition between isogenic untransformed cells and BCR-Abl-transformed cells, and identified several compounds that selectively target BCR-Abl-transformed cells. Systems-level analysis of one of these novel compounds, DJ34, revealed that it induced depletion of c-Myc and activation of p53. c-Myc depletion occurred in a wide range of tumor types, including leukemia, lymphoma, lung, glioblastoma and breast cancer. Further analyses revealed that DJ34 interferes with c-Myc synthesis at the level of transcription, and we provide data showing that DJ34 is a DNA intercalator and topoisomerase II inhibitor. Physiologically, DJ34 induced apoptosis, cell cycle arrest and cell differentiation, and primary leukemic stem cells were particularly sensitive to DJ34. Taken together, we have identified a novel compound that dually targets c-Myc and p53 in a wide variety of cancers, and with particularly strong activity against leukemic stem cells.
Project description:Muscle stem cell quiescence is a complex and dynamic state. In this study we examined the role of the Ubiquitin Protease System in muscle stem cell function and quiescence. Using a genetic mouse model where Nedd4L is selectively deleted in myogenic cells, we characterized the effect of the loss of Nedd4L on muscle stem cells. With RNA-Seq we determined that the genetic deletion of Nedd4L resulted in the transition of the muscle stem cells out of deep quiescence and into Galert. Characterized by the upregulation of cell cycle genes and differentiation genes and loss of expression in numerous known quiescence genes. Nedd4L-cKO muscle stem cells are more prone to differentiation and fail to expand properly in vitro.
Project description:Muscle stem cell quiescence is a complex and dynamic state. In this study we examined the role of the Ubiquitin Protease System in muscle stem cell function and quiescence. Using a genetic mouse model where Nedd4L is selectively deleted in myogenic cells, we characterized the effect of the loss of Nedd4L on muscle stem cells. With RNA-Seq we determined that the genetic deletion of Nedd4L resulted in the transition of the muscle stem cells out of deep quiescence and into Galert. Characterized by the upregulation of cell cycle genes and differentiation genes and loss of expression in numerous known quiescence genes. Nedd4L-cKO muscle stem cells are more prone to differentiation and fail to expand properly in vitro.
Project description:Knowledge of cell signaling pathways that drive human neural crest differentiation into craniofacial chondrocytes is incomplete, yet essential for using stem cells to regenerate craniomaxillofacial structures. To accelerate translational progress, we developed a differentiation protocol that generated self-organizing craniofacial cartilage organoids from human embryonic stem cell-derived neural crest stem cells. Histological staining of cartilage organoids revealed tissue architecture and staining typical of elastic cartilage. Protein and post-translational modification (PTM) mass spectrometry and snRNASeq data showed that chondrocyte organoids expressed robust levels of cartilage extracellular matrix (ECM) components: many collagens, aggrecan, perlecan, proteoglycans, and elastic fibers. We identified two populations of chondroprogenitor cells, mesenchyme cells and nascent chondrocytes and the growth factors involved in paracrine signaling between them. We show that ECM components secreted by chondrocytes not only create a structurally resilient matrix that defines cartilage, but also play a pivotal autocrine cell signaling role to determine chondrocyte fate.
Project description:Increased treatment of metastatic castration resistant prostate cancer (mCRPC) with second-generation anti-androgen therapies (ADT) has coincided with a greater incidence of lethal, aggressive variant prostate cancer (AVPC) tumors that have lost androgen receptor (AR) signaling. AVPC tumors may also express neuroendocrine markers, termed neuroendocrine prostate cancer (NEPC). Recent evidence suggests kinase signaling may be an important driver of NEPC. To identify targetable kinases in NEPC, we performed global phosphoproteomics comparing AR-negative to AR-positive prostate cancer cell lines and identified multiple altered signaling pathways, including enrichment of RET kinase activity in the AR-negative cell lines. Clinical NEPC and NEPC patient derived xenografts displayed upregulated RET transcript and RET pathway activity. Pharmacologically inhibiting RET kinase in NEPC models dramatically reduced tumor growth and cell viability in mouse and human NEPC models. Our results suggest that targeting RET in NEPC tumors with high RET expression may be a novel treatment option.
Project description:Increased treatment of metastatic castration resistant prostate cancer (mCRPC) with second-generation anti-androgen therapies (ADT) has coincided with a greater incidence of lethal, aggressive variant prostate cancer (AVPC) tumors that have lost androgen receptor (AR) signaling. AVPC tumors may also express neuroendocrine markers, termed neuroendocrine prostate cancer (NEPC). Recent evidence suggests kinase signaling may be an important driver of NEPC. To identify targetable kinases in NEPC, we performed global phosphoproteomics comparing AR-negative to AR-positive prostate cancer cell lines and identified multiple altered signaling pathways, including enrichment of RET kinase activity in the AR-negative cell lines. Clinical NEPC and NEPC patient derived xenografts displayed upregulated RET transcript and RET pathway activity. Pharmacologically inhibiting RET kinase in NEPC models dramatically reduced tumor growth and cell viability in mouse and human NEPC models. Our results suggest that targeting RET in NEPC tumors with high RET expression may be a novel treatment option.
Project description:Here, we introduce a reversible protein tag, ProMTag, that enables whole proteome capture, cleanup, and release of intact proteins for top-down analysis. Alternatively, the addition of a novel Trypsin derivative to the workflow generates peptides for bottom-up analysis. We show that the ProMTag workflow yields >90% for intact proteins and >85% for proteome digests. For top-down analysis, ProMTag cleanup improves resolution on 2D gels; for bottom-up exploration, this methodology produced reproducible mass spectrometry results, demonstrating that the ProMTag method is a truly universal approach that produces high quality proteome samples compatible with multiple downstream analytical techniques.
Project description:Acute leukemias represent deadly malignancies which require better treatment. As challenge, treatment is counteracted by a microenvironment protecting dormant leukemia stem cells. To identify responsible surface proteins, we performed deep proteome profiling on minute numbers of dormant patient-derived xenograft (PDX) leukemia stem cells isolated from mice. Candidates were functionally screened by establishing a comprehensive CRISPR-Cas9 pipeline in PDX models in vivo. A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) was identified as essential vulnerability required for survival and growth of different types of acute leukemias in vivo and reconstitution assays in PDX models proved the relevance of its sheddase activity. Of translational importance, molecular or pharmacological targeting of ADAM10 reduced PDX leukemia burden, cell homing to the murine bone marrow and stem cell frequency, and increased leukemia response to conventional chemotherapy in vivo. These findings identify ADAM10 as attractive therapeutic target for future treatment of acute leukemias.
Project description:Dilated cardiomyopathy (DCM), a myocardial disorder that can result in progressive heart failure and arrhythmias, is defined by ventricular chamber enlargement and dilatation, and systolic dysfunction. To decipher the basis for the cardiac pathology in titin-mutated patients, we investigated the hypothesis that induced Pluripotent Stem Cell (iPSC)- derived cardiomyocytes (iPSC-CM) generated from patients, recapitulate the disease phenotype.Our findings show that the mutated cardiomyocytes from DCM patients recapitulate abnormalities of the inherited cardiomyopathies.
Project description:CDK4/6 kinase inhibitors have shown great promise in clinical trials in various cancer types and have recently entered clinical trial for advanced prostate cancer. Although patients are expected to respond well to this class of drugs, development of resistance in some patients is anticipated. To pre-empt this and study how prostate cancer may evade CDK4/6 inhibition, new resistance models were generated from LNCaP and LAPC4 prostate cancer cells cells by prolonged culturing in presence of 0.5uM palbociclib. A shotgun phosphoproteomics approach was utilized and integrated with RNA sequencing data to unravel the molecular underpinnings of acquired resistance to palbociclib and resultant broad CDK4/6 inhibitor resistance.