Noncoding RNAs (ncRNAs) represent a large segment of the human transcriptome and have been shown to play important roles in cellular physiology and disease pathogenesis. Increasing evidence on the functional roles of ncRNAs in cancer progression emphasizes the potential of ncRNAs for cancer treatment. Here, we summarize the roles of ncRNAs in disease relapse and resistance to current standard chemotherapy and radiotherapy; the current research progress on ncRNAs for clinical and/or potential translational applications, including the identification of ncRNAs as therapeutic targets; therapeutic approaches for ncRNA targeting; and ncRNA delivery strategies in potential clinical translation. Several ongoing clinical trials of novel RNA-based therapeutics were also emphasized. Finally, we discussed the perspectives and obstacles to different target combinations, delivery strategies, and system designs for ncRNA application. The next approved nucleic acid drug to treat cancer patients may realistically be on the horizon.

Sun et al identify a circular RNA, circMYBL2, that upregulates FLT3 translation to promote FLT3-ITD acute myeloid leukemia (AML) progression, suggesting a novel therapeutic target for FLT3-ITD AML.

The long noncoding RNA ANRIL has been found to be abnormally expressed and play important roles in different cancers. However, the expression and function of ANRIL in acute myeloid leukemia (AML) remain to be declared. In this study, we found that ANRIL is up-regulated in AML patients at diagnosis and down-regulated in patients after complete remission (CR). Functional studies showed that knockdown of ANRIL expression resulted in a decline in glucose uptake and inhibition of AML cell maintenance in vitro and in vivo. Mechanically, ANRIL was found to repress the expression of Adiponectin receptor (AdipoR1), a key regulator of glucose metabolism. Both ANRIL and AdipoR1 knockdown reduced the expression levels of phosphorylation of AMPK and SIRT1, implying a previously unappreciated ANRIL-AdipoR1-AMPK/SIRT1 signaling pathway in regulating cell glucose metabolism and survival in AML. The study is the first to demonstrate that ANRIL promotes malignant cell survival and cell glucose metabolism to accelerate AML progression and is a potential prognostic marker and therapeutic target in AML treatment.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0879-9) contains supplementary material, which is available to authorized users.

Background Circular RNAs (circRNAs) represent a type of endogenous noncoding RNAs that are generated by back-splicing events and favor repetitive sequences. Recent studies have reported that cancer-associated chromosomal translocations could juxtapose distant complementary repetitive intronic sequences, resulting in the aberrant formation of circRNAs. However, among the reported fusion genes, only a small number of circRNAs were found to originate from fusion regions during gene translocation. We question if circRNAs could also originate from fusion partners during gene translocation. Methods Firstly, we designed divergent primers for qRT-PCR to identify a circRNA circAF4 in AF4 gene and investigated the expression pattern in different types of leukemia samples. Secondly, we designed two small interfering RNAs specially targeting the back-spliced junction point of circAF4 for functional studies. CCK8 cell proliferation and cell cycle assay were performed, and a NOD-SCID mouse model was used to investigate the contribution of circAF4 in leukemogenesis. Finally, luciferase reporter assay, AGO2 RNA immunoprecipitation (RIP), and RNA Fluorescent in Situ Hybridization (FISH) were performed to confirm the relationship of miR-128-3p, circAF4, and MLL-AF4 expression. Results We discovered a circRNA, named circAF4, originating from the AF4 gene, a partner of the MLL fusion gene in MLL-AF4 leukemia. We showed that circAF4 plays an oncogenic role in MLL-AF4 leukemia and promotes leukemogenesis in vitro and in vivo. More importantly, knockdown of circAF4 increases the leukemic cell apoptosis rate in MLL-AF4 leukemia cells, while no effect was observed in leukemia cells that do not carry the MLL-AF4 translocation. Mechanically, circAF4 can act as a miR-128-3p sponge, thereby releasing its inhibition on MLL-AF4 expression. We finally analyzed most of the MLL fusion genes loci and found that a number of circRNAs could originate from these partners, suggesting the potential roles of fusion gene partner-originating circRNAs (named as FP-circRNAs) in leukemia with chromosomal translocations. Conclusion Our findings demonstrate that the abnormal elevated expression of circAF4 regulates the cell growth via the circAF4/miR-128-3p/MLL-AF4 axis, which could contribute to leukemogenesis, suggesting that circAF4 may be a novel therapeutic target of MLL-AF4 leukemia.

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