Project description:The MMSET (Multiple Myeloma SET domain) protein is overexpressed in multiple myeloma patients with the translocation t(4;14). Although studies have shown the involvement of MMSET/WHSC1 in development, its mode of action in the pathogenesis of multiple myeloma (MM) is largely unknown. We found that MMSET is a major regulator of chromatin structure and transcription in t(4;14) MM cells. High levels of MMSET correlate with an increase in lysine 36 methylation of histone H3 and a decrease in lysine 27 methylation across the genome, leading to a more open structural state of the chromatin. Loss of MMSET expression alters adhesion properties, suppresses growth and induces apoptosis in MM cells. Consequently, genes affected by high levels of MMSET are implicated in the p53 pathway, cell cycle regulation and integrin signaling. Regulation of many of these genes required functional histone methyl-transferase (HMT) activity of MMSET. These results implicate MMSET as a major epigenetic regulator in t(4;14)+ MM.
Project description:Multiple myeloma (MM) is characterized by recurrent chromosomal translocations. The translocation t(4;14)(p16;q32) is one of the most common translocation in MMs, affecting 15% of patients, and is associated with very poor prognosis. The histone methyltransferase (HMTase) MMSET is universally overexpressed in t(4;14) MM as a result of the t(4;14) translocation. MMSET is capable of producing 3 major isoforms, the full length MMSET II, short isoforms REIIBP and MMSET I. MMSET II has been suggested to play an important tumorigenic role in t(4;14) MM, but little is yet known about whether and how the MMSET short isoforms contribute to MM tumorigenesis. The aim of this study is to characterize MMSET I roles and determine its downstream targets in t(4;14) MM. In t(4;14) MM cells MMSET I knockdown with shRNAs induced cell apoptosis, reduced colony formation and inhibited tumorigenicity in vivo. We also found MMSET I knockdown decreased GLO1 expression, and ectopic MMSET I increased GLO1 expression, suggesting that MMSET I is an upstream regulator of GLO1. Further analysis indicated that MMSET I bound to GLO1 promoter region and depended on its C-terminus to regulate GLO1 expression. Our preliminary data suggested that MMSET I is an oncoprotein and could regulate GLO1 expression in t(4;14) multiple myeloma cells.
Project description:The MMSET (Multiple Myeloma SET domain) protein is overexpressed in multiple myeloma patients with the translocation t(4;14). Although studies have shown the involvement of MMSET/WHSC1 in development, its mode of action in the pathogenesis of multiple myeloma (MM) is largely unknown. We found that MMSET is a major regulator of chromatin structure and transcription in t(4;14) MM cells. High levels of MMSET correlate with an increase in lysine 36 methylation of histone H3 and a decrease in lysine 27 methylation across the genome, leading to a more open structural state of the chromatin. Loss of MMSET expression alters adhesion properties, suppresses growth and induces apoptosis in MM cells. Consequently, genes affected by high levels of MMSET are implicated in the p53 pathway, cell cycle regulation and integrin signaling. Regulation of many of these genes required functional histone methyl-transferase (HMT) activity of MMSET. These results implicate MMSET as a major epigenetic regulator in t(4;14)+ MM. Total RNA was isolated from two different systems: an inducible knock down designed in the 5' region of MMSET. Upon addition of doxycycline we block MMSET expression. The second system we used was a repletion system. By retroviral infection of knock out cells for MMSET we restored the expression of MMSET wild type and two mutants of the protein: one active and one catalytically inactive. Triplicates of each sample were analyzed.
Project description:Multiple myeloma (MM) is characterized by recurrent chromosomal translocations. The multiple myeloma SET domain (MMSET), identified by its fusion to the IgH locus in t(4;14) MM, is universally overexpressed and has been suggested to play an important role in tumorigenicity in t(4;14) MM. In order to identify downstream functional targets of MMSET, we knocked down MMSET expression with shRNAs in KMS11, a t(4;14) MM cell line, and identified differentially expressed genes by gene expression microarray analysis.
Project description:NSD2, a histone lysine methyltransferase, is overexpressed as a result of the t(4;14) translocation that is associated with 15-20% of multiple myeloma. Earlier studies have indicated that NSD2 may be involved in myelomagenesis and suggested that it may be a target for myeloma therapy. Here we show that NSD2 is required for clonogenic growth, adherence and proliferation on bone marrow stroma, and tumorigenesis of t(4;14)+ but not t(4;14)- myeloma cells, in a methyltransferase activity dependent manner. Furthermore, we found that PHD domains are important for NSD2 cellular activity and biological functions by recruiting it to oncogenic gene loci and driving downstream transcription activation events. These results strengthened the disease link of NSD2 and provided a basis that targeting NSD2 may be a therapeutic strategy in multiple myeloma patients with t(4;14) translocation. Our data also revealed multiple domains in the protein for possible chemical modulation. To elucidate the mechanisms underlying the oncogenic potential of NSD2 in myeloma, we performed microarray analysis on KMS11 parental (PAR), TKO and 8 reconstituted lines. Based on the whole-genome expression profile, the 10 samples clearly fell into 4 clusters – (1) PAR; (2) TKO; (3) WT, WT+MMSET I, 526-1240 and 526-1365; and (4) CDM, CDM+MMSET I, MMSET I and H762Y
Project description:We performed gene expression profiling to understand the mechansims of cytotoxic effects of an MMSET inhibitor on t(4;14)-positive multiple myeloma cells.
Project description:Multiple myeloma (MM) is characterized by recurrent chromosomal translocations. The multiple myeloma SET domain (MMSET), identified by its fusion to the IgH locus in t(4;14) MM, is universally overexpressed and has been suggested to play an important role in tumorigenicity in t(4;14) MM. In order to identify downstream functional targets of MMSET, we knocked down MMSET expression with shRNAs in KMS11, a t(4;14) MM cell line, and identified differentially expressed genes by gene expression microarray analysis. KMS11 cells were treated with shRNAs for 48 h. Total RNA was extracted by using the Qiagen RNeasy Mini kit (Germany). Gene expression was performed using the GeneChip Human Genome U133A Array (Affymetrix) following the manufacturerM-bM-^@M-^Ys instructions. Data analysis was performed using GeneSpring software from Agilent Technologies.
Project description:We investigated EZH2 binding in the presence and absence of MMSET protein. MMSET overexpression in t(4;14)+ myeloma leads to global loss of H3K27 methylation and redistribution of EZH2 binding throughout the genome
Project description:NSD2, a histone lysine methyltransferase, is overexpressed as a result of the t(4;14) translocation that is associated with 15-20% of multiple myeloma. Earlier studies have indicated that NSD2 may be involved in myelomagenesis and suggested that it may be a target for myeloma therapy. Here we show that NSD2 is required for clonogenic growth, adherence and proliferation on bone marrow stroma, and tumorigenesis of t(4;14)+ but not t(4;14)- myeloma cells, in a methyltransferase activity dependent manner. Furthermore, we found that PHD domains are important for NSD2 cellular activity and biological functions by recruiting it to oncogenic gene loci and driving downstream transcription activation events. These results strengthened the disease link of NSD2 and provided a basis that targeting NSD2 may be a therapeutic strategy in multiple myeloma patients with t(4;14) translocation. Our data also revealed multiple domains in the protein for possible chemical modulation. To elucidate the mechanisms underlying the oncogenic potential of NSD2 in myeloma, we performed microarray analysis on KMS11 parental (PAR), TKO and 8 reconstituted lines. Based on the whole-genome expression profile, the 10 samples clearly fell into 4 clusters – (1) PAR; (2) TKO; (3) WT, WT+MMSET I, 526-1240 and 526-1365; and (4) CDM, CDM+MMSET I, MMSET I and H762Y Biological triplicates of cell cultures of indicated lines were harvested in TRIzol (Invitrogen) and characterized by human U133 plus 2.0 Affymetrix GeneChip. The gene expression data was normalized using the Robust Multiarray Averaging (RMA) method and log2 transformed before comparisons.
Project description:We investigated EZH2 binding in the presence and absence of MMSET protein. MMSET overexpression in t(4;14)+ myeloma leads to global loss of H3K27 methylation and redistribution of EZH2 binding throughout the genome ChIP-seq for EZH2 in two cell types