Project description:Acquired drug resistance and tumour relapse impacts the majority of patients being treated with tyrosine kinase inhibitors (TKIs) and remains a key challenge in modern anti-cancer therapy. The lack of clinically effective therapeutic strategies to overcome drug resistance represents a significant unmet need. Understanding the signalling pathways that drive drug resistance will facilitate the development of new salvage therapies to effectively treat patients with secondary TKI resistance. In this study, we utilise quantitative mass spectrometry to characterise the global phosphoproteomic alterations that accompany the acquisition of resistance to two FDA-approved multi-target TKIs, pazopanib and dasatinib, in the A204 rhabdoid tumour cell line. Our analysis finds that only a limited fraction of the quantified phosphoproteome (<10%) is altered upon the acquisition of drug resistance with pazopanib resistant cells displaying elevated phosphorylation levels in cytoskeletal regulatory pathways and dasatinib resistant cells showing an upregulation of components of the insulin receptor/IGF1-R signalling pathway. Drug response profiling with a targeted panel of small molecule inhibitors rediscovers several previously reported vulnerabilities associated with pazopanib and dasatinib resistance and identifies a new dependency to the second generation HSP90 inhibitor NVP-AUY-922. This study provides a useful resource detailing the candidate signalling determinants of acquired TKI resistance; and reveals a therapeutic approach of inhibiting HSP90 function as a means of salvage therapy to overcome pazopanib and dasatinib resistance.
Project description:Malignant rhabdoid tumors (MRT) represent one of the most aggressive childhood malignancies. No effective treatment options are available, and prognosis is therefore dismal. Previous studies have demonstrated that tumor organoids capture the heterogeneity of patient tumors and can be used to predict patient therapy response. Here, we perform drug screening on patient-derived normal and tumor organoids to identify MRT-specific therapeutic vulnerabilities. We identify neddylation inhibitor MLN4924 as a potential therapeutic agent. Mechanistically, we find increased neddylation in MRT organoids and tissues and show that MLN4924 induces a cytotoxic response via upregulation of the unfolded protein response. Lastly, we demonstrate in vivo efficacy in an MRT PDX mouse model, in which single agent MLN4924 treatment significantly extends survival. Our study demonstrates that organoids can be used to find drugs selectively targeting tumor cells while leaving healthy cells unharmed and proposes neddylation inhibition as therapeutic strategy in MRT.
Project description:Atypical teratoid/rhabdoid tumor (AT/RT), which harbors INI1 mutation and exhibits a characteristic histology of rhabdoid cells, has a poor prognosis because of the lack of effective treatments. Here we established human INI1-deficient pluripotent stem cells (hPSCs), which developed AT/RT formation in vivo. However, INI1-deficient hPSC-derived neural progenitor cell (NPC) gave rise to mostly medulloblastoma-like tumors when transplanted into the mouse brain.
Project description:Medulloblastoma (MB) is among the most common malignant brain tumors in children. Recent studies have identified at least four subgroups of the disease that differ in terms of molecular characteristics and patient outcomes. Despite this heterogeneity, most MB patients receive similar therapies, including surgery, radiation and intensive chemotherapy. Although these treatments prolong survival, many patients still die from the disease, and survivors suffer severe long-term side effects from therapy. We hypothesize that each MB patient is sensitive to different therapies, and that tailoring therapy based on the molecular and cellular characteristics of patients’ tumors will improve outcomes. To test this, we have assembled a panel of orthotopic patient-derived xenografts (PDXs) and subjected them to DNA sequencing, gene expression profiling and high-throughput drug screening. Analysis of DNA sequencing suggests that most MBs do not have actionable mutations that point to effective therapies. In contrast, gene expression and drug response data provide valuable information about potential therapies for every tumor. For example, drug screening demonstrates that actinomycin D – which is used for treatment of sarcoma but rarely for MB – is active against PDXs representing Group 3 MB, the most aggressive form of the disease. Finally, we show that functional analysis of tumor cells can be used in a clinical setting to identify more treatment options than sequencing alone. These studies suggest that it should be possible to move away from a one-size-fits-all approach and begin to treat each patient with therapies that are effective against their tumor.
Project description:Medulloblastoma (MB) is among the most common malignant brain tumors in children. Recent studies have identified at least four subgroups of the disease that differ in terms of molecular characteristics and patient outcomes. Despite this heterogeneity, most MB patients receive similar therapies, including surgery, radiation and intensive chemotherapy. Although these treatments prolong survival, many patients still die from the disease, and survivors suffer severe long-term side effects from therapy. We hypothesize that each MB patient is sensitive to different therapies, and that tailoring therapy based on the molecular and cellular characteristics of patients’ tumors will improve outcomes. To test this, we have assembled a panel of orthotopic patient-derived xenografts (PDXs) and subjected them to DNA sequencing, gene expression profiling and high-throughput drug screening. Analysis of DNA sequencing suggests that most MBs do not have actionable mutations that point to effective therapies. In contrast, gene expression and drug response data provide valuable information about potential therapies for every tumor. For example, drug screening demonstrates that actinomycin D – which is used for treatment of sarcoma but rarely for MB – is active against PDXs representing Group 3 MB, the most aggressive form of the disease. Finally, we show that functional analysis of tumor cells can be used in a clinical setting to identify more treatment options than sequencing alone. These studies suggest that it should be possible to move away from a one-size-fits-all approach and begin to treat each patient with therapies that are effective against their tumor.
Project description:Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft-tissue sarcomas which lack effective drugs. Previous studies support the usefulness of MEK inhibitors (MEKis) for treating RAS-driven tumors, however, the lack of preclinical assessment of MEK inhibitors in MPNSTs limit the clinical application as well as the development of combination therapy. In this study, we comprehensively evaluated 8 MEK inhibitors in terms of efficiency, safety and mechanisms of resistance for treating MPNSTs. We identified the most promising MEK inhibitor, trametinib, for the treatment of MPNSTs. Through high-throughput transcriptomic sequencing and drug screening, we discovered the upregulation of integrin signaling contributing to MEK inhibitor resistance, termed as cell adhesion-mediated drug resistance (CAM-DR). We also confirmed MET overactivation in MEKi-resistant MPNST cells. These targets are potential solutions to overcome MEKi- resistance in clinical applications.
Project description:We hypothesized that prolonged treatment of malignant rhabdoid tumor cells with low-dose HDACi will drive cellular differentiation. We assessed changes in gene expression following 21 days treatment with the HDACi, Panobinostat, versus a DMSO vehcile control in three human MRT cell lines. Total RNA obtained from three human malignant rhabdoid tumor cell lines (G401, SJSC, STM91-01) cultured for 21 days in the presence of low-dose Panobinostat was compared to 21-day treated DMSO control cells. All treatments and cell lines were performed in triplicate.
Project description:Malignant pleural mesothelioma (MPM), which is associated with occupational asbestos exposure, is a deadly disease with no effective treatments due mainly to its high resistance to anti-cancer drugs. The molecular mechanisms responsible for its chemotherapeutic resistance are complicated and undefined. However, the presence of side population cells (SP cells) in tumors is a well-accepted explanation for their anti-cancer drug resistance. To identify SP cell-specific gene expression signature, microarray technique has been employed. Our data show differential gene expression profiles between SP and non-SP cells of H2714 mesothelioma cells. SP cells over-expressed genes associated with cancer stem cell (CSC) and drug resistance: DUSP6, SPRY2 and IL6, as well as multi-pathways, including the cancer stem cell-associated pathways Notch and c-Kit. Therefore, we believe that targeting CSC-specific genes and pathways in SP cells may hold the key to the discovery of effective treatments for reversing chemotherapeutic resistance to MPM treatment. 4 samples