Long non-coding RNA HULC as a diagnostic and prognostic marker of pancreatic cancer.

BACKGROUND: Long non-coding RNA (lncRNA) is abnormally expressed in various malignant tumors. In recent years, it has been found that IncRNA HULC is increasingly expressed in pancreatic cancer tissues and is involved in the development and progression of pancreatic cancer. However, the clinical value of serum HULC in pancreatic cancer remains unclear, and there are few studies on how HULC regulates the biological function of pancreatic cancer cells. AIM: To determine the value of lncRNA HULC in the diagnosis and prognosis of pancreatic cancer, and its possible biological potential. METHODS: Sixty patients with pancreatic cancer and sixty patients with benign pancreatic diseases admitted to Xiangya Hospital, Central South University were assigned to the pancreatic cancer group and the benign disease group, respectively, and another 60 healthy subjects were enrolled as the normal group during the same period. HULC-siRNA and NC-siRNA were transfected into pancreatic cancer cells. Quantitative real-time polymerase chain reaction was performed to determine the expression of HULC in tissues, serum, and cells. Western Blot was carried out to determine the expression of ß-catenin, c-myc, and cyclin D1 in cells, and the cell counting kit-8, flow cytometry, and Transwell assay were conducted to determine the proliferation, apoptosis and invasion of cells. RESULTS: Highly expressed in the tissues and serum of pancreatic cancer patients, HULC showed good clinical value in distinguishing between patients with pancreatic cancer, patients with benign pancreatic diseases and healthy subjects. HULC was related to pathological parameters including tumor size, T staging, M staging and vascular invasion, and the area-under-the-curve for evaluating these four parameters was 0.844, 0.834, 0.928 and 0.818, respectively. Patients with low expression of HULC had a significantly higher 3-year overall survival (OS) and 5-year OS than those with high expression. T staging, M staging, vascular invasion, and HULC were independent prognostic factors affecting the 3-year OS of patients with pancreatic cancer. Inhibition of HULC expression prevented the proliferation and invasion of pancreatic cancer cells, promoted apoptosis, and inhibited the expression of Wnt/ß-catenin signaling pathway-related proteins, ß-catenin, c-myc, and cyclin D1. The Wnt/ß-catenin signaling pathway agonist (LiCl) restored proliferation, apoptosis, and invasion of pancreatic cancer cells with inhibited expression of HULC. CONCLUSION: HULC is an effective marker for the diagnosis and prognosis of pancreatic cancer, which may affect the biological function of pancreatic cancer cells through the Wnt/ß-catenin signaling pathway.

Hypoxia-induced shedding of MICA and HIF1A-mediated immune escape of pancreatic cancer cells from NK cells: role of circ_0000977/miR-153 axis.

One key to malignant progression of pancreatic cancer (PC) is the acquired ability of tumour cells to escape immune-mediated lysis. Hypoxic microenvironment plays a causal role in PC metastasis. According to previous studies, hypoxia could induce the upregulation of HIF1A, ADAM10 and sMICA, leading to decreased NKG2D in NK cells and tumour cells escape from immune surveillance and NK cell-mediated lysis. In the present study, in NK cells derived from high-HIF1A expression patients, the levels of internalization of MICA/B and NKG2D were obviously higher than those in low-HIF1A expression group; hypoxia dramatically upregulated the levels of sMICA culture supernatant of Panc-1 cells. Regarding the molecular mechanism, dysregulated circRNAs and miRNAs that might modulate HIF1A-mediated immune escape were selected and examined for detailed functions. The expression of circ_0000977 could be induced by hypoxia, and circ_0000977 knockdown enhanced the killing effect of NK cells on PC cells under hypoxia through HIF1A and ADAM10. HIF1 and ADAM10 were direct downstream targets of miR-153; circ_0000977 served as a sponge for miR-153 to counteract miR-153-mediated repression of HIF1 and ADAM10 mRNA through direct targeting in both 293T cells and Panc-1 cells. miR-153 inhibition exerted an opposing effect on HIF1A-mediated immune escape of PC cells to circ_0000977 knockdown; the effect of circ_0000977 knockdown were partially attenuated by miR-153 inhibition. In summary, circ_0000977/miR-153 axis modulates HIF1A-mediated immune escape of PC cells through miR-153 downstream targets HIF1A and ADAM10. We provided a novel mechanism of HIF1A-mediated immune escape of PC cells from the perspective of circRNAs-miRNA-mRNA axis. Abbreviations: Pancreatic cancer (PC); peripheral blood lymphocytes (PBLs); A Disintegrin and Metalloproteinase Domain 10 (ADAM10); MHC class I-related molecule A (MICA); soluble MICA (sMICA); membrane MICA (mMICA); Hypoxia-inducible factor 1-alpha (HI1FA); long non-coding RNAs (lncRNAs); non-coding RNAs (ncRNAs); natural killer (NK); Haematoxylin and eosin (H&E); Immunohistochemistry (IHC); natural killer group 2 member D (NKG2D).

Long noncoding RNA FEZF1-AS1 predicts poor prognosis and modulates pancreatic cancer cell proliferation and invasion through miR-142/HIF-1α and miR-133a/EGFR upon hypoxia/normoxia.

Nowadays, pancreatic cancer (PC) remains the most lethal tumor, partially due to the invasive and treatment-resistant phenotype induced by the extent of hypoxic stress within the tumor tissue. According to previous studies, miR-142/HIF-1α and miR-133a/EGFR could modulate PC cell proliferation under hypoxic and normoxic conditions, respectively. In the present study, FEZF1-AS1, a recently described oncogenic long noncoding RNA, was predicted to target both miR-142 and miR-133a; thus, we hypothesized that FEZF1-AS1 might affect PC cell proliferation through these two axes under hypoxic or normoxic conditions. In PC cell lines, FEZF1-AS1 acted as an oncogene via promoting PC cell proliferation and invasion through miR-142/HIF-1α axis under hypoxic condition; however, FEZF1-AS1 failed to affect the protein levels of HIF-1α and VEGF under the normoxic condition, suggesting the existence of another signaling pathway under normoxic condition. As predicted by an online tool, FEZF1-AS1 could target miR-133a to inhibit its expression; under the normoxic condition, FEZF1-AS1 exerted its effect on PC cell lines through miR-133a/EGFR axis. Taken together, FEZF1-AS1 might be a promising target in controlling the aberrant proliferation and invasion of PC cell lines.

Long noncoding RNA NNT-AS1 promotes hepatocellular carcinoma progression and metastasis through miR-363/CDK6 axis.

Long non-coding RNAs (lncRNAs) have been tested to act as important regulator in liver cancer genesis and progression. LncRNA Nicotinamide Nucleotide Transhydrogenase-antisense RNA1 (NNT-AS1) has been reported to participate in the tumorigenesis. However, the exact molecular mechanism of NNT-AS1 in hepatocellular carcinoma (HCC) is still unknown. In present study, our team identified the up-regulated expression of NNT-AS1 in HCC tissue and cell lines compared with adjacent noncancerous tissue and normal cells. Moreover, HCC patients with high NNT-AS1 levels had poor prognosis than that with low NNT-AS1 level (p=0.0089). In vitro, gain- and loss-of-function experiments revealed that enhanced NNT-AS1 expression promoted the proliferation ability and alleviated the cycle arrest and apoptosis, while NNT-AS1 knockdown suppressed the proliferation and induced G0/G1 phase arrest and apoptosis. In vivo, NNT-AS1 knockdown inhibited the HCC neoplastic tumor volume and weight. Bioinformatics analysis and luciferase reporter assay validated that miR-363 targeted NNT-AS1 and CDK6 3'-UTR. MiR-363 was down-regulated in HCC tissue and cells. NNT-AS1 competed with CDK6 for miR-363 binding and could increase CDK6 expression. In summary, our results suggest the oncogenic role of NNT-AS1 in HCC tumorigenesis through miR-363/CDK6 axis, providing a novel therapeutic target for human HCC.