Long non-coding RNA PLUM controls PRC2-mediated H3K27 methylation in multiple myeloma to promote chemoresistance

ABSTRACT: Multiple myeloma (MM) ranks the second most prevalent haematological malignancy globally. Despite advancements in managing MM, it remains incurable due to the high genetic heterogeneity leading to treatment resistance and disease severity. One key drug resistance associated signalling pathway often hyperactivated in MM patients is the non-canonical NF- κB/p52 pathway. Additionally, dysregulated expression of various oncogenic long non-coding RNAs (lncRNAs) have been observed in MM. This study aims to examine the potential link between ncNF-κB activation and dysregulated lncRNA expression controlling the chemoresistance and oncogenic progression of MM. Using mutant MM cell lines as model system and omics data from MM patients, we identified a novel p52 regulated lncRNA enriched in high-risk MM patients. The lncRNA termed PLUM (PRC2 associated LncRNA regulating UPR in MM) is found to interact directly with PRC2 complex to mediate myeloma progression and chemoresistance. RACE (Rapid amplification of cDNA ends) analysis revealed PLUM exists in three main isoforms in drug resistant multiple myeloma cell lines (MMCLs), comprising 8 exons without coding potential. Functionally, PLUM exerts its oncogenic and drug resistance properties in vivo and in vitro via the activation of unfolded protein response (UPR) pathway. This is consistent with its elevated expression in VRd (Bortezomib- Lenalidomide-Dexamethasone) non-responsive MM patients. PLUM localizes predominantly in the nucleus where it interacts directly with the disordered region of EZH2 (489-494 aa residues) to facilitate formation of the PRC2 complex and EZH2 activity. Disruption of this interaction using steric antisense oligonucleotides (ASOs) re-sensitized MMCLs to drug treatment in vitro and in vivo, correlating with the loss of EZH2 H3K27 trimethylation activity and PRC2 complex stability. Finally, we demonstrate that PLUM-EZH2 regulates the expression of tumour suppressor genes, FOXO3 and ZFP36, to activate the UPR pathway and promote chemoresistance in MM. These findings indicate that ncNF-κB pathway regulated lncRNA PLUM is oncogenic, acting through the PRC2/FOXO3/ZFP36 axis to confer chemoresistance in MM.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Plasma Cell

DISEASE(S): Multiple Myeloma

SUBMITTER: Dennis Kappei  

LAB HEAD: Dennis Kappei

PROVIDER: PXD054586 | Pride | 2025-06-23

REPOSITORIES: Pride