Che-1/miR-590-3p/TAZ axis sustains multiple myeloma disease

Multiple myeloma (MM) is a blood disease characterized by the malignant accumulation of monoclonal plasma cells in the bone marrow. Among the pathological consequences of the MM, defects in osteogenesis characterized by osteolytic lesions, osteopenia, and pathologic fractures are frequently described. Che-1/AATF (Che-1) is a co-transcriptional factor involved in MM transformation and proliferation. Here, we show that Che-1 expression in MM contributes to maintaining low level of WWTR1 (TAZ), a transcriptional coactivator downstream of the Hippo-signaling pathway. We report that the miR-590-3p, deriving from the mRNA splicing of the EIF4H host gene, can target TAZ, contributing to downregulating its expression in MM. Furthermore, we demonstrate by in vivo and in vitro experiments that Che-1 transcriptionally induces EIF4H gene. We provide data to support that miR-590-3p is secreted by MM cells in vitro and in vivo and that can inhibit TAZ levels and the physiological transcriptional expression of osteogenic-related genes, in mesenchymal stem cells. Our findings unveil an unexplored novel Che-1/miR-590-3p/TAZ axis in MM tumorigenesis by providing a rationale to explore the therapeutic potential of metastatic bone lesions.