Long non-coding RNA NORAD promotes pancreatic cancer stem cell proliferation and self-renewal by blocking microRNA-202-5p-mediated ANP32E inhibition

Abstract

Background Cancer stem cells (CSCs) are key regulators in the processes of tumor initiation, progression, and recurrence. The mechanism that maintains their stemness remains enigmatic, although the role of several long noncoding RNAs (lncRNAs) has been highlighted in the pancreatic cancer stem cells (PCSCs). In this study, we first established that PCSCs overexpressing lncRNA NORAD, and then investigated the effects of NORAD on the maintenance of PCSC stemness. Methods Expression of lncRNA NORAD, miR-202-5p and ANP32E in PC tissues and cell lines was quantified after RNA isolation. Dual-luciferase reporter assay, RNA pull-down and RIP assays were performed to verify the interactions among NORAD, miR-202-5p and ANP32E. We then carried out gain- and loss-of function of miR-202-5p, ANP32E and NORAD in PANC-1 cell line, followed by measurement of the aldehyde dehydrogenase activity, cell viability, apoptosis, cell cycle distribution, colony formation, self-renewal ability and tumorigenicity of PC cells. Results LncRNA NORAD and ANP32E were upregulated in PC tissues and cells, whereas the miR-202-5p level was down-regulated. LncRNA NORAD competitively bound to miR-202-5p, and promoted the expression of the miR-202-5p target gene ANP32E thereby promoting PC cell viability, proliferation, and self-renewal ability in vitro, as well as facilitating tumorigenesis of PCSCs in vivo. Conclusion Overall, lncRNA NORAD upregulates ANP32E expression by competitively binding to miR-202-5, which accelerates the proliferation and self-renewal of PCSCs.

Solute Carrier Family 35 Member F2 Regulates Cisplatin Resistance and Promotes Malignant Progression of Pancreatic Cancer by Regulating RNA Binding Motif Protein 14

“…All the samples had not received medical treatment and/or radiation treatment before surgery. The inclusion and exclusion criteria were according to a previous report [ 17 ]. Immediately after collection, the excised experimental specimens were immersed in an EP tube containing a preservation solution and stored in a −80°C refrigerator.…”

“…After culture for 48 h, total RNA was extracted from transfected cells using TRIzol reagent (Beyotime, Shanghai, China) and then reverse-transcribed using the PrimeScript RT reagent kit (KeyGen company, Nanjing, China). The protocols of RT-PCR were according to a previous report [ 17 ]. Each sample was tested in triplicate wells and repeated three times.…”

Vitamin D May Protect against Breast Cancer through the Regulation of Long Noncoding RNAs by VDR Signaling

“…Therefore, vitamin D3/VDR signaling may prevent acquiring a stem-like phenotype by normal mammary gland progenitors and somatic breast cancer cells ( Figure 2 ). Several pathways involved in cancer stemness are modulated by lncRNAs, and their targeting may be considered a new strategy to control tumor development, invasion, metastasis, and therapeutic resistance (e.g., [ 32 , 33 , 34 ]).…”

The microRNA-202 as a Diagnostic Biomarker and a Potential Tumor Suppressor

“…Numerous clinical studies have addressed the role of miR-202 in gastrointestinal tract tumors (GIT), including oral [ 12 ], esophageal [ 19 , 20 , 21 ], gastric [ 22 , 23 , 24 ], pancreatic [ 25 , 26 , 27 , 28 ], hepatocellular [ 29 , 30 , 31 ], and colorectal [ 32 , 33 , 34 , 35 ] cancers, and documented a lower expression of miR-202 in tumor tissues and a tumor suppressive function of miR-202 overexpression on GIT cancer progression. In oral cancer cell lines, overexpression of miR-202 downregulated the protein expression level of the transcription factor Sp1, which, in turn, reduced cancer cell migration and invasion.…”

“…Pancreatic cancer (PC) is currently rated as the fourth leading cause of cancer-related death worldwide [ 39 ]. A tumor suppressor function for miR-202 in pancreatic carcinoma is suggested by all preclinical and clinical studies up to date [ 25 , 26 , 27 , 28 ]. lncRNA NORAD and ANP32E were upregulated in PC tissues and cells, whereas the miR-202-5p level was down-regulated.…”