RESUMO
Long noncoding RNAs (lncRNAs) are deregulated in human cancers and are associated with disease progression. Plasmacytoma Variant Translocation 1 (PVT1), a lncRNA, is located adjacent to the gene MYC, which has been linked to multiple myeloma (MM). PVT1 is expressed in MM and is associated with carcinogenesis. However, its role and regulation remain uncertain. We examined PVT1/MYC expression using real-time PCR in plasma cells purified from 59 monoclonal gammopathy of undetermined significance (MGUS) and 140 MM patients. The MM cell lines KMS11, KMS12PE, OPM2, and RPMI8226 were treated with JQ1, an MYC super-enhancer inhibitor, or MYC inhibitor 10058-F4. The expression levels of PVT1 and MYC were significantly higher in MM than in MGUS (p < 0.0001) and were positively correlated with disease progression (r = 0.394, p < 0.0001). JQ1 inhibited cell proliferation and decreased the expression levels of MYC and PVT1. However, 10054-F4 did not alter the expression level of PVT1. The positive correlation between MYC and PVT1 in patients, the synchronous downregulation of MYC and PVT1 by JQ1, and the lack of effect of the MYC inhibitor on PVT1 expression suggest that the expression of these two genes is co-regulated by a super-enhancer. Cooperative effects between these two genes may contribute to MM pathogenesis and progression.
Assuntos
Carcinogênese/genética , Proteínas de Ciclo Celular/genética , Progressão da Doença , Gamopatia Monoclonal de Significância Indeterminada/genética , Mieloma Múltiplo/genética , RNA Longo não Codificante/genética , Fatores de Transcrição/genética , Acetamidas/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Azepinas/farmacologia , Proteínas de Ciclo Celular/antagonistas & inibidores , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inativação Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Gamopatia Monoclonal de Significância Indeterminada/patologia , Mieloma Múltiplo/patologia , Plasmócitos/metabolismo , Proteínas Proto-Oncogênicas c-myc/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-myc/genética , Tiazóis/farmacologia , Fatores de Transcrição/antagonistas & inibidores , Triazóis/farmacologia , Adulto JovemRESUMO
Extramedullary myeloma (EMM) occurs when myeloma develops outside the bone marrow; it often develops after chemotherapy and is associated with the acquisition of chemo-resistance and a fatal course. The mechanisms underlying extramedullary spread have not yet been fully elucidated. MALAT1 is a highly abundantly and ubiquitously expressed long non-coding RNA that plays important roles in cancer metastasis. The aims of this study were to clarify the association of MALAT1 with EMM and to elucidate the underlying mechanism of EMM formation under chemotherapeutic pressure. MALAT1 expression was significantly higher in multiple myeloma (MM) than in monoclonal gammopathy of undetermined significance. Furthermore, MALAT1 expression was markedly higher in EMM compared with that in corresponding intramedullary myeloma cells. A higher MALAT1 level was associated with shorter overall and progression-free survival. MALAT1 expression level was positively correlated with expression of HSP90AA1, HSP90AB1 and HSP90B1 but not with TP53 expression. MALAT1 was significantly upregulated by bortezomib and doxorubicin. Considering the known functions of MALAT1, our results suggest that it acts as a stress response gene that is upregulated by chemotherapy, thereby linking chemotherapy to EMM formation. Elucidating the biological implication of long non-coding RNA contributes to deeper understanding concerning the pathogenesis and investigation of novel therapeutic targets for MM.