Expression and functional relevance of long non-coding RNAs in acute myeloid leukemia stem cells
LEUKEMIA
Authors: Bill, Marius; Papaioannou, Dimitrios; Karunasiri, Malith; Kohlschmidt, Jessica; Pepe, Felice; Walker, Christopher J.; Walker, Allison E.; Brannan, Zachary; Pathmanathan, Aparna; Zhang, Xiaoli; Mrozek, Krzysztof; LaRocco, Allison; Volinia, Stefano; Bloomfield, Clara D.; Garzon, Ramiro; Dorrance, Adrienne M.
Abstract
In acute myeloid leukemia (AML), novel therapies are needed to target not only the rapidly dividing AML blasts but also the distinct population of leukemia stem cells (LSCs), which have abnormal self-renewal capacity and increased chemotherapy resistance. Elucidation of the expression and function of deregulated genes in LSCs is critical to specifically target LSCs and may consequently lead to improving outcomes of AML patients. Here, we correlated long non-coding RNA (lncRNA) expression profiles obtained from two RNA-seq datasets of 375 younger (aged <60 years) 76 older (>= 60 years) adults with cytogenetically normal AML with a 'core enriched' (CE) gene expression signature (GES) associated with LSCs. We identified a LSC-specific signature of 111 lncRNAs that correlated strongly with the CE-GES. Among the top upregulated LSC-associated lncRNAs, we identified the lncRNA DANCR. Further experiments confirmed that DANCR is upregulated in functionally validated LSC-enriched populations. DANCR knock-down in LSCs resulted in decreased stem-cell renewal and quiescence. Furthermore, we showed that targeting Dancr in vivo using a primary murine model of AML (expressing both Mll partial tandem duplication/Flt3 internal tandem duplication) prolonged the survival of mice after serial transplantation. Our data suggest that LSCs have a distinct lncRNA signature with functional relevance and therapeutic potential.
AFF4 regulates osteogenic differentiation of human dental follicle cells
INTERNATIONAL JOURNAL OF ORAL SCIENCE
Authors: Xiao, Qingyue; Zhang, Yuning; Qi, Xingying; Chen, Yaqian; Sheng, Rui; Xu, Ruoshi; Yuan, Quan; Zhou, Chenchen
Abstract
As a member of the AFF (AF4/FMR2) family, AFF4 is a transcription elongation factor that is a component of the super elongation complex. AFF4 serves as a scaffolding protein that connects transcription factors and promotes gene transcription through elongation and chromatin remodelling. Here, we investigated the effect of AFF4 on human dental follicle cells (DFCs) in osteogenic differentiation. In this study, we found that small interfering RNA-mediated depletion ofAFF4resulted in decreased alkaline phosphatase (ALP) activity and impaired mineralization. In addition, the expression of osteogenic-related genes (DLX5,SP7,RUNX2andBGLAP) was significantly downregulated. In contrast, lentivirus-mediated overexpression ofAFF4significantly enhanced the osteogenic potential of human DFCs. Mechanistically, we found that both the mRNA and protein levels of ALKBH1, a critical regulator of epigenetics, changed in accordance with AFF4 expression levels. Overexpression ofALKBH1inAFF4-depleted DFCs partially rescued the impairment of osteogenic differentiation. Our data indicated that AFF4 promoted the osteogenic differentiation of DFCs by upregulating the transcription ofALKBH1.