PO-162 Long non coding RNA H19 (IncH19) is required for the hypoxia mediated multiple myeloma progression

Abstract

IntroductionMultiple myeloma (MM) is a malignant disorder of post-germinal centre B cells, characterised by the clonal proliferation of malignant plasma cells within the bone marrow (BM). The hypoxic condition that develops in the BM niche during progression of MM, has been shown to play a major role in i) the dissemination of MM, ii) the proliferation of MM cells and iii) the induction of drug resistance finally determining a poor prognosis for MM patients. The molecular mechanisms driving hypoxic responses is the activation and nuclear translocation of the Hypoxia-inducible factor 1-alpha, (HIF1α) that, in turns, induce the expression of genes controlling angiogenesis, hypermetabolism, stemnes maintenance, resistance to chemotherapy, and tumour metastasis. The lncRNA H19, an imprinted non-coding RNA which expression was found up-regulated in many tumours including MM, is among the targets of HIF1α.We previously attributed to the lncH19 a role into control of hypoxic response; in particular we demonstrated, in both glioblastoma and colon cancer, that the lncH19, is necessary and required to sustain HIF1α activity. Here we propose to investigate the role of lncH19 in hypoxia mediated MM progression.Material and methodsTranscriptional analysis (RT-PCR) of MM cell lines (RPMI and MM1S) exposed to normoxia or hypoxia (1% O2) was done in order to evaluate lncH19 levels under hypoxic stimulation. To investigate the role of lncH19 in hypoxia mediated MM progression, transcriptional, protein and functional assays have been performed on MM cell lines, silenced or not for lncH19, under normoxia or 24 hour hypoxic stimulation in low oxygen chamberResults and discussionsOur data indicate that MM cell lines respond to hypoxic stimulation by HIF1α nuclear translocation and activation of hypoxic responsive genes including the lncH19. Our data revealed that lncH19 silencing inhibits HIF1a nuclear translocation with a subsequent reduction in the expression of hypoxia induced genes, associated to MM progression, such as snail and VEGF. Moreover, adhesion assay of MM cells on Mesenchymal Stromal Cells revealed that lncH19 silencing abrogates the increased adhesion induced by hypoxic condition.ConclusionLncH19 is required for the induction of hypoxic responses in MM cells thus representing a new therapeutic target for MM. Further studies are required to better define the molecular mechanism through which H19 may control HIF1α activity.