ABSTRACT
CCND1, FGFR3 and c-MAF mRNA expression of tumor samples from 123 multiple myeloma patients were analyzed by global RQ/RT-PCR. CCND1, FGFR3 and c-MAF were positive in 44 (36%), 28 (23%) and 16 (13%) of patients, respectively. In 7 patients, both FGFR3 and c-MAF were positive. The expression of c-MAF was independent unfavorable prognostic factors for overall survival (OS). Autologous stem cell transplantation improved progression-free survival of CCND1-positive patients. Bortezomib, thalidomide or lenalidomide extended OS of FGFR3 and/or c-MAF-positive patients. Thus, CCND1, FGFR3 and c-MAF mRNA expression can predict survival and is useful for planning stratified treatment strategies for myeloma patients.
Subject(s)
Biomarkers, Tumor/genetics , Chromosomes, Human, Pair 14/genetics , Multiple Myeloma/genetics , Proto-Oncogenes/genetics , Translocation, Genetic/genetics , Adult , Aged , Aged, 80 and over , Case-Control Studies , Female , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , Multiple Myeloma/diagnosis , Multiple Myeloma/mortality , Prognosis , Real-Time Polymerase Chain Reaction , Survival AnalysisABSTRACT
ARK5, AMP-activated protein kinase (AMPK)-related protein kinase mediating Akt signals, is closely involved in tumor progression, and its stage-associated expression was observed in colorectal cancer. In this study, we found ARK5 expression in multiple myeloma cell lines expressing c-MAF and MAFB. In addition, gene expression profiling of 351 clinical specimens revealed ARK5 expression in primary myelomas expressing c-MAF and MAFB, suggesting that ARK5 may be a transcriptional target of the Large-MAF family. Sequence analysis of the ARK5 gene promoter revealed that it contains two putative MAF-recognition element (MARE) sequences. In support of this hypothesis, ARK5 was induced when an MAFB or c-MAF expression vector was introduced into non-ARK5-expressing colon cancer cells. Furthermore, ARK5 promoter activity was dramatically decreased by mutation or deletion of MARE sequences. Chromatin immunoprecipitation assays revealed an interaction between the Large-MAF family proteins and MARE sequences in the ARK5 promoter. Moreover, in ARK5 mRNA-expressing multiple myeloma lines, but not in ARK5-negative lines, insulin-like growth factor (IGF)-1 increased invasion activity. IGF-1-induced invasion was reproduced when ARK5 was overexpressed in Burkitt's lymphoma and plasmacytoma lines. Based on results, we conclude that ARK5 is a transcriptional target of the Large-MAF family through MARE sequence and that ARK5 may in part mediate the aggressive phenotype associated with c-MAF- and MAFB-expressing myelomas.
Subject(s)
Gene Expression Regulation, Neoplastic/physiology , Maf Transcription Factors, Large/physiology , Multiple Myeloma/genetics , Protein Kinases/genetics , Repressor Proteins/genetics , Transcription, Genetic/physiology , Base Sequence , Cell Line, Tumor , DNA Primers , Humans , Multiple Myeloma/pathology , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
A global real-time quantitative/reverse transcription-polymerase chain reaction technique for detecting the expression of six 14q32 chromosomal translocation-associated proto-oncogenes in marrow plasma cells was established and applied to myeloma specimens. This technique is an alternative method of detecting 14q32 rearrangements and allows investigation of the relationship between proto-oncogene expression and clinical features.
Subject(s)
Chromosomes, Human, Pair 14 , Multiple Myeloma/genetics , Proto-Oncogenes/genetics , Reverse Transcriptase Polymerase Chain Reaction/methods , Translocation, Genetic/genetics , Gene Expression , Humans , Proto-Oncogene MasABSTRACT
One Japanese pedigree of familial essential thrombocythemia (FET) inherited in an autosomal-dominant manner is presented. A unique point mutation, serine 505 to asparagine 505 (Ser505Asn), was identified in the transmembrane domain of the c-MPL gene in all of the 8 members with thrombocythemia, but in none of the other 8 unaffected members in this FET family. The Ba/F3 cells expressing the mutant Asn505 acquired interleukin 3 (IL-3)-independent survival capacity, whereas those expressing wild-type Ser505 did not. The autonomous phosphorylation of Mek1/2 and Stat5b was observed in the mutant Ba/F3 cells in the absence of IL-3. The former was also found in platelets derived from the affected individual in the absence of thrombopoietin. These results show that the Asn505 is an activating mutation with respect to the intracellular signaling and survival of the cells. This is the first report of FET deriving from a dominant-positive activating mutation of the c-MPL gene.
