Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Assessment of MEK-ERK pathway targeting by BRAF, NRAS and KRAS gene mutations in plasma cell dyscrasias [Patient samples]

ABSTRACT: Multiple myeloma (MM) is a malignant disorder characterized by the clonal proliferation of plasma cells (PCs) in the bone marrow (BM). The genetic background and clinical course of the disease are largely heterogeneous, and MM pathophysiology ranges from the premalignant condition of monoclonal gammopathy of undetermined significance (MGUS) to smoldering MM, symptomatic MM, and extramedullary MM/plasma cell leukemia (PCL). Recent genome-wide sequencing efforts have provided the rationale for molecularly aimed treatment approaches, identifying mutations that can be specifically targeted, such as those in the mitogen-activated protein kinase (MAPK) pathway, which represent the most prevalent mutations in MM. Among these, mutations affecting BRAF gene, detected in 4-15% of patients, are of potential immediate clinical relevance due to the availability of effective inhibitors of this serine-threonine kinase which are in fact being explored also in myeloma. In this study, we screened by next generation sequencing (NGS) a large and representative series of intramedullary and extramedullary MM patients, including primary and secondary plasma cell leukemia (pPCL and sPCL, respectively), for mutations in BRAF, NRAS and KRAS genes. We evaluated the relationship of identified variants with other clinical and biological features and determined the transcriptional signature associated with MAPK pathway activation in MM. To identify transcriptomic profiles possibly related to BRAF, NRAS and KRAS mutations found in our study, we investigated by Affymetrix microarray technology a large fraction (n=142) of the samples analyzed by NGS, including wild-type patients for all the three genes and cases carrying mutations in at least one of them. Assuming that alterations present in a very limited number of malignant PCs might not appreciably affect gene expression, we chose to arbitrarily establish 20% as the lower variant allele frequency cut-off to perform supervised analyses.

ORGANISM(S): Homo sapiens

SUBMITTER: Luca Agnelli

PROVIDER: E-GEOD-66291 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Molecular spectrum of BRAF, NRAS and KRAS gene mutations in plasma cell dyscrasias: implication for MEK-ERK pathway activation.

Lionetti Marta M Barbieri Marzia M Todoerti Katia K Agnelli Luca L Marzorati Simona S Fabris Sonia S Ciceri Gabriella G Galletti Serena S Milesi Giulia G Manzoni Martina M Mazzoni Mara M Greco Angela A Tonon Giovanni G Musto Pellegrino P Baldini Luca L Neri Antonino A

Oncotarget 20150901 27

Multiple myeloma (MM) is a clinically and genetically heterogeneous plasma cell (PC) malignancy. Whole-exome sequencing has identified therapeutically targetable mutations such as those in the mitogen-activated protein kinase (MAPK) pathway, which are the most prevalent MM mutations. We used deep sequencing to screen 167 representative patients with PC dyscrasias [132 with MM, 24 with primary PC leukemia (pPCL) and 11 with secondary PC leukemia (sPCL)] for mutations in BRAF, NRAS and KRAS, which ...[more]

PMID: 26090869

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Project description:Multiple myeloma (MM) is a malignant disorder characterized by the clonal proliferation of plasma cells (PCs) in the bone marrow (BM). The genetic background and clinical course of the disease are largely heterogeneous, and MM pathophysiology ranges from the premalignant condition of monoclonal gammopathy of undetermined significance (MGUS) to smoldering MM, symptomatic MM, and extramedullary MM/plasma cell leukemia (PCL). Recent genome-wide sequencing efforts have provided the rationale for molecularly aimed treatment approaches, identifying mutations that can be specifically targeted, such as those in the mitogen-activated protein kinase (MAPK) pathway, which represent the most prevalent mutations in MM. Among these, mutations affecting BRAF gene, detected in 4-15% of patients, are of potential immediate clinical relevance due to the availability of effective inhibitors of this serine-threonine kinase which are in fact being explored also in myeloma. In this study, we screened by next generation sequencing (NGS) a large and representative series of intramedullary and extramedullary MM patients, including primary and secondary plasma cell leukemia (pPCL and sPCL, respectively), for mutations in BRAF, NRAS and KRAS genes. We evaluated the relationship of identified variants with other clinical and biological features and determined the transcriptional signature associated with MAPK pathway activation in MM. To further elucidate the transcriptional programs modulated by BRAF activation in MM, we used the PLX4032 drug to inhibit BRAF activity in U266 human myeloma cell line (HMCL), carrying K601N mutation and showing constitutive activation of MEK/ERK signaling. After confirming its ability to suppress MAPK pathway and myeloma cell proliferation in culture in the U266 cell line, we investigated the specific modulation of gene expression induced by the drug. U266 cells were treated with PLX4032 (30 µM) or DMSO for 12 hours and subjected to gene expression profiling (GEP) analysis by using Affymetrix GeneChip Human Gene 1.0ST arrays.

Project description:A rare complication of multiple myeloma is a secondary extramedullary involvement, and the skin is one of the possible sites, due to the physiological homing of plasma cells (PCs) into the skin. The article reports a case of a relapsed refractory MM patient, who developed a cutaneous localization after 16 months from the diagnosis under Bortezomib treatment without a leukemic phase. Patient was refractory to Bortezomib. We analyzed the gene expression profiles, the immunophenotypic and immunohistochemistry profiles of MM cells across the course of the disease at the bone marrow and skin localization. Data obtained were further expanded by an immunohistochemistry analysis on selected molecules in a large cohort of MM patients with cutaneous localization. In particular we focused on the expression of chemokines and chemokine receptors involved in the PC skin homing. The mechanisms behind the extramedullary spread and the formation of localizations outside the BM are not completely understood. Several studies investigated the expression profile of myeloma cells in the extramedullary localization by immunohistochemistry without a prospective molecular and immunohistochemistry study across the progression of the disease and consequently the development of extramedullary localization. This case indicates that the skin homing of MM cells could be related to the high CCR10 expression of at the diagnosis and relapse and the loss of CXCR4 surface expression across the progression of the disease in the contest of Bortezomib resistance. This data was further confirmed in a larger series of patients. Moreover, high expression of CD44, together with the down-regulation of CD54 and the lack of expression of CD56 by MM cells in the BM relapse with the re-acquisition of both antigens during the cutaneous relapse may be the mechanism that drives the escape from BM of PCs and their localization into the skin. Our data have identified a possible mechanism that drives the escape from BM of myeloma cells and their localization into the skin.

Dataset Information

Assessment of MEK-ERK pathway targeting by BRAF, NRAS and KRAS gene mutations in plasma cell dyscrasias [Patient samples]

Publications

Molecular spectrum of BRAF, NRAS and KRAS gene mutations in plasma cell dyscrasias: implication for MEK-ERK pathway activation.

Similar Datasets

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