Project description:Cutaneous melanoma (CM) and uveal melanoma (UM) both originate from the melanocytic lineage but are primarily driven by distinct oncogenic drivers, BRAF/NRAS or GNAQ/GNA11 respectively. The melanocytic master transcriptional regulator, MITF, is essential for both CM development and maintenance, but its role in UM is largely unexplored. Here, we use zebrafish models to dissect the key UM oncogenic signaling events, and establish the role of MITF in UM tumors. Remarkably, mitfa deficiency was profoundly UM promoting, dramatically accelerating the onset and progression of tumors induced by Tg(mitfa:GNAQQ209L);tp53M214K/M214K. To further explore the role of MITF in GNAQ-driven tumorigenesis, we performed phospho-proteomics and total proteomics on 5 zebrafish GNAQ Tg(mitfa:GNAQQ209L);tp53M214K/M214K tumors and 5 zebrafish GNAQ Tg(mitfa:GNAQQ209L);tp53M214K/M214K;mitfa-/- tumors.
Project description:Cutaneous melanoma (CM) and uveal melanoma (UM) both originate from the melanocytic lineage but are primarily driven by distinct oncogenic drivers, BRAF/NRAS or GNAQ/GNA11 respectively. The melanocytic master transcriptional regulator, MITF, is essential for both CM development and maintenance, but its role in UM is largely unexplored. Here, we use zebrafish models to dissect the key UM oncogenic signaling events, and establish the role of MITF in UM tumors. Using a melanocytic lineage expression system, we showed that patient-derived mutations of GNAQ (GNAQQ209L) or its upstream CYSLTR2 receptor (CYSLTR2L129Q) both drive UM when combined with a cooperating mutation, tp53M214K/M214K. The tumor-initiating potential of the major GNAQ/11 effector pathways, YAP and PLCβ-ERK, was also investigated in this system, and thus showed that while activated YAP (YAPAA) induced UM with high potency, the patient-derived PLC4 mutation (PLCB4D630Y) very rarely yielded UM tumors in the tp53M214K/M214K context. Remarkably, mitfa deficiency was profoundly UM promoting, dramatically accelerating the onset and progression of tumors induced by Tg(GNAQQ209L);tp53M214K/M214K or Tg(CYSLTR2L129Q);tp53M214K/M214K. Moreover, mitfa loss was sufficient to cooperate with GNAQQ209L to drive tp53-wildtype UM development, and allowed Tg(PLCB4D630Y);tp53M214K/M214K melanocyte lineage cells to readily form tumors. Notably, all of the mitfa-/- UM tumors, including those arising in Tg(mitfa:PLCB4D630Y);tp53M214K/M214K;mitfa-/- fish, displayed nuclear YAP while lacking hyperactive ERK indicative of PLCβ signaling. Collectively, these data show that YAP signaling is the major mediator of UM, and that MITF acts as bona fide tumor suppressor in UM, in direct opposition to its essential role in CM.
Project description:We developed an isogenic melanocytic cellular system and systematically examined the hotspot mutations in GNAQ (e.g., G48V, R183Q, Q209L) and CYSLTR2 (e.g. L129Q) in human uveal melanoma. Biochemical and cell viability assays validated YM-254890 as a potent inhibitor of cell signaling and growth. Human uveal melanoma cells and mouse models recapitulated this finding, indicating that YM is also effective in vivo. Combination of YM and MEK inhibition leads to further decreases in MAPK pathway gene expression and cell viability. Furthermore, our cellular and mouse models show that combination leads to long term signaling inhibition and significant decreases in tumor burden.
Project description:We developed an isogenic melanocytic cellular system and systematically examined the hotspot mutations in GNAQ (e.g., G48V, R183Q, Q209L) and CYSLTR2 (e.g. L129Q) in human uveal melanoma. Biochemical and cell viability assays validated YM-254890 as a potent inhibitor of cell signaling and growth. Human uveal melanoma cells and mouse models recapitulated this finding, indicating that YM is also effective in vivo. Combination of YM and MEK inhibition leads to further decreases in MAPK pathway gene expression and cell viability. Furthermore, our cellular and mouse models show that combination leads to long term signaling inhibition and significant decreases in tumor burden.
Project description:Activating GNAQ/GNA11 are present in majority of uveal melanomas resulting in downstream activation of the MAPK pathway. To elucidate changes in the transcriptome after MEK or ERK1/2 inhibition, we performed RNA sequencing on two UM cell lines. Differential analysis revealed that MARK3 expression was not altered but STK10 expression was reduced.
Project description:We used microarray to compare global gene expression profiles between 5 GNAQ/11 mutant uveal melanoma cell lines (GNAQ mutant: 92-1, omm1.3, mel270; GNA11 mutant: omm-gn11 and upmd-1) and 5 GNAQ/11 wild type melanoma cell lines(sk-mel-2, mm415, mm485, sk-mel-5 and mum2c). Uveal melanoma is the most common intraocular tumor that mainly metastasizes to the liver in about 50% patients. Over 80% of UMs harbor GNAQ or GNA11 activating mutation. Currently there is no effective treatment available for UM patients. Results provide insights into downstream signaling of oncogenic GNAQ/11 and identification of therapeutic targets in UM.
Project description:Genome wide DNA methylation profiling of primary uveal melanoma cells, normal uveal melanocytes, neural crest stem cells, embryonic stem cells and uveal melanoma cell lines. The Illumina Infinium 27k Human DNA methylation Beadchip Rev B was used to obtain DNA methylation profiles across approximately 27,000 CpGs in the samples. Samples included 58 primary UM, 3 NUM and NCSC controls and 2 cell lines. Bisulphite converted DNA from the 63 samples were hybridised to the Illumina Infinium 27k Human Methylation Beadchip Rev B
Project description:Karyotyping by SNP array of primary uveal melanoma samples, uveal melanoma cell lines and normal controls The Human660WQuad v1.0 DNA Analysis Bead Chip and kit were used for high resolution molecular karyotyping of DNA isolated from snap-frozen primary uveal melanoma tissue isolated from enucleated eyes.
Project description:Despite advances in surgery and radiotherapy of uveal melanoma (UM), many patients develop distant metastases that poorly respond to therapy. Improved therapies for the metastatic disease are therefore urgently needed. Expression of the epidermal growth factor receptor (EGFR), a target of kinase inhibitors and humanized antibodies in use for several cancers, had been reported. 48 human UMs were analyzed by expression profiling. Evidence for signaling in tumors was obtained through the application of a UM-specific EGF signature. The EGFR specific kinase inhibitor, Gefitinib, and the humanized monoclonal antibody, Cetuximab, were tested for their effect on EGFR signaling. Natural killer cell mediated antibody-dependent cellular cytotoxicity (ADCC) and TNF-alpha release was analyzed for Cetuximab. EGFR appears suited as a novel molecular drug target for therapy of uveal melanoma. Gene expression profiles of 19 unique samples from uveal melanoma patients were measured.
Project description:Genome wide DNA methylation profiling of primary uveal melanoma cells, normal uveal melanocytes, neural crest stem cells, embryonic stem cells and uveal melanoma cell lines. The Illumina Infinium 27k Human DNA methylation Beadchip Rev B was used to obtain DNA methylation profiles across approximately 27,000 CpGs in the samples. Samples included 58 primary UM, 3 NUM and NCSC controls and 2 cell lines.