Project description:We performed gene expression profiling in the human papillary thyroid carcinoma (PTC) derived cell line BCPAP harboring BRAFV600E mutation following the treatment with BRAF selective inhibitors.
Project description:To analyse the RNA expression differences between melanoma tumour samples treated with BRAF and MEK-inhibitors at different time points
Project description:Transcriptional profiles of formalin-fixed-paraffin-embedded melanoma metastases including pre-treatment (PRE) and post-treatment (POST) specimens from 50 patients treated with BRAF inhibitors or with BRAF and MEK inhibitors
Project description:Selective RAF inhibitors including vemurafenib (PLX4032) have demonstrated clinical efficacy in mutant BRAF driven metastatic melanoma. The clinical effectiveness of RAF inhibitors depends on near complete abolition of the MAPK pathway output in tumors harboring BRAF mutations. However these compounds paradoxically activate the MAPK pathway in cells bearing oncogenic RAS or elevated upstream receptor signaling. This paradox can promote cellular proliferation and can manifest clinically with progression of secondary malignancies such as cutaneous squamous cell carcinomas (cuSCC). We have identified next generation RAF inhibitors (“paradox breakers”, e.g. PLX7904) that inhibit mutant BRAF cells without activating the MAPK pathway in cells bearing upstream activation. In murine cuSCC B9 cells that express the same HRAS mutation prevalent in squamous tumors from patients treated with RAF inhibitors, the first-generation RAF PLX4032 stimulated in vitro and in vivo growth; by contrast the paradox breaker PLX7904 had no effect. Here we compared the gene expression changes in B9 cells treated overnight with PLX4032 and PLX7904.
Project description:Gene expression profiles of matched pre- and post-treatment melanoma metastasis from seven patients treated with BRAF inhibitors (BRAFi)
Project description:Hairy cell leukemia (HCL) shows unique clinico-pathological and biological features. HCL responds well to purine analogues but relapses are frequent and novel therapies are required. BRAF-V600E is the key driver mutation in HCL and distinguishes it from other B-cell lymphomas, including HCL-like leukemias/lymphomas (HCL-variant and splenic marginal zone lymphoma). The kinase-activating BRAF-V600E mutation also represents an ideal therapeutic target in HCL. Here, we investigated the biological and therapeutic importance of the activated BRAF-MEK-ERK pathway in HCL by exposing in vitro primary leukemic cells purified from 26 patients to clinically available BRAF (Vemurafenib; Dabrafenib) or MEK (Trametinib) inhibitors. Results were validated in vivo in samples from Vemurafenib-treated HCL patients within a phase-2 clinical trial. BRAF and MEK inhibitors caused, specifically in HCL (but not HCL-like) cells, marked MEK/ERK dephosphorylation, silencing of the BRAF-MEK-ERK pathway transcriptional output, loss of the HCL-specific gene expression signature, downregulation of the HCL markers CD25, TRAP and cyclin-D1, smoothening of leukemic cells' hairy surface, and, eventually, apoptosis. Apoptosis was partially blunted by co-culture with bone marrow stromal cells antagonizing MEK-ERK dephosphorylation. This protective effect could be counteracted by combined BRAF and MEK inhibition. Our results strongly support and inform the clinical use of BRAF and MEK inhibitors in HCL. Analysis of differential gene expression in primary leukemic cells purified from peripheral blood of 6 HCL patients (from A to F), treated with Vemurafenib 1000 nM, in comparison with vehicle-treated (DMSO) HCL cells, for 48 hours or/and 72 hours. 24 gene expression profiles were analysed.
Project description:Melanoma is an aggressive skin cancer with increasing incidence worldwide. The development of BRAF kinase inhibitors as targeted treatments for patients with BRAF-mutant tumours contributed profoundly to an improved overall survival of patients with metastatic melanoma. Despite these promising results, the emergence of rapid resistance to targeted therapy remains a serious clinical issue. To investigate the impact of BRAF inhibitors on miRNomes and transcriptomes, we used in vitro melanoma models consisting of BRAF inhibitor-sensitive and -resistant cell lines generated in our laboratory. miRNA and gene expression were assessed by microarray analyses of the BRAF inhibitor sensitive melanoma cells A375, IGR37, and 501Mel, as well as on the vemurafenib (PLX4032) - resistant cells A375_XP, IGR37_XP, 501Mel_XP, and dabrafenib (GSK2118436) - resistant cells A375_GP, IGR37_GP, 501Mel_GP. For each cell line the microarray experiment was performed in duplicates.
Project description:Erythropoiesis is a crucial part in hematopoietic system, while facing disruptions from various diseases conditions. Anemia and blood shortages has become global challenges, with current finite pharmacological options like EPO or glucocorticoids having limitations, especially in genetic anemias like Diamond-Blackfan anemia (DBA), calling for novel candidates in stimulating the erythropoiesis. We designed the primary human hematopoietic stem and progenitor cells (HSPCs) chemicals screening system in erythropoiesis and unexpectedly discovered a BRAF inhibitor, effectively against BRAFV600E mutant cancers, delaying erythroid differentiation while promoting progenitors’ proliferation. Further research demonstrated its efficacy in cytokine-restricted conditions and in samples from erythroid disorder patients. Mechanistically, BRAF inhibitors paradoxically activated the RAF-MEK-ERK/MAPK pathway. Unlike oncogenic BRAFV600E impaired hematopoiesis and erythropoiesis via AP-1 hyperactivation, BRAF inhibitors minimally affected HSPCs self-renewal and differentiation. In vivo studies further exhibited BRAF inhibitors' potential to enhance human hematopoiesis and erythropoiesis in severe immunodeficient mouse models and alleviate anemia symptoms in Rpl11 haploinsufficiency DBA models and other anemia models. This discovery sheds light on the MAPK pathway's role in hematopoiesis, making BRAF inhibitors a novel clinically therapeutic choice in improving hematopoietic reconstitution and the recovery of anemias like DBA.
Project description:Melanoma is an aggressive skin cancer with increasing incidence worldwide. The development of BRAF kinase inhibitors as targeted treatments for patients with BRAF-mutant tumours contributed profoundly to an improved overall survival of patients with metastatic melanoma. Despite these promising results, the emergence of rapid resistance to targeted therapy remains a serious clinical issue. To investigate the impact of BRAF inhibitors on miRNomes and transcriptomes, we used in vitro melanoma models consisting of BRAF inhibitor-sensitive and -resistant cell lines generated in our laboratory. miRNA and gene expression were assessed by microarray analyses of the BRAF inhibitor sensitive melanoma cells A375, IGR37, and 501Mel, as well as on the vemurafenib (PLX4032) - resistant cells A375_XP, IGR37_XP, 501Mel_XP, and dabrafenib (GSK2118436) - resistant cells A375_GP, IGR37_GP, 501Mel_GP. For each cell line the microarray experiment was performed in duplicates.