LncRNA LINP1 promotes malignant progression of pancreatic cancer by adsorbing microRNA-491-3p
Authors: G-Q Liu
K Zhang
A-Y Chen
Journal: European review for medical and pharmacological sciences (2020)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: lncRNA LINP1; pancreatic cancer; microRNA-491-3p; qRT-PCR; tumor tissue
Affiliations: Department of Oncology, Liaocheng Infectious Disease Hospital, Liaocheng, China. .

Abstract:  Objective: The purpose of this study was to explore the mechanism by which long noncoding RNA (lncRNA) LINP1 promoted the development of pancreatic cancer (PCa). Meanwhile, the regulatory relationship between lncRNA LINP1 and microRNA-491-3p was further investigated to provide an effective theoretical basis for the treatment of this cancer. Patients and methods: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was carried out to examine lncRNA LINP1 and microRNA-491-3p expression in tumor tissue specimens collected from 56 PCa patients, and the interplay between lncRNA LINP1 expression and some clinical indicators, as well as prognosis of patients with PCa was also analyzed. Meanwhile, in vitro, qRT-PCR further verified lncRNA LINP1 level in PCa cell lines. In addition, lncRNA LINP1 knockdown model was constructed using lentivirus in PCa cell lines CFPAC-1 and BxPC-3, and Cell Counting Kit-8 (CCK-8), transwell, and cell wound healing assays were carried out to evaluate the impact of lncRNA LINP1 on the function of PCa cells. Finally, Dual-Luciferase reporting assay and cell reverse experiments were applied to uncover the potential mechanism. Results: QRT-PCR revealed that lncRNA LINP1 showed a significantly higher expression in pancreatic tumor tissue samples than in adjacent normal ones. Compared with patients with low expression of lncRNA LINP1, patients with highly expressed lncRNA LINP1 showed a higher incidence of distant metastasis, but a lower overall survival rate. In addition, compared to the sh-NC group, the proliferation, invasion, and migration ability of PCa cells decreased remarkably in LINP1 knockdown group. The results of Luciferase reporting assay demonstrated that lncRNA LINP1 could be targeted by microRNA-491-3p through a specific binding site, and qRT-PCR results uncovered a negative correlation between microRNA-491-3p and lncRNA LINP1 expression in PCa tissues. Finally, the recovery experiment revealed a mutual regulation between LINP1 and microRNA-491-3p, which may jointly regulate the malignant progression of PCa. Conclusions: LncRNA LINP1 is able to enhance the proliferation and metastasis of PCa cells by modulating microRNA-491-3p, thus affecting the incidence of lymph node or distant metastasis and prognosis of patients with PCa. 

Retracted: No

PubPeer comments:
 Figs 1D, 3E.  Kaplan-Meier survival curve of PCa patients based on LncRNA LINP1 expression. Patients with high expression group have significantly worse prognosis than low expression group ...  Kaplan Meier survival curve of PCa patients based on miR-491-3p expression, and the prognosis of patients with low expression was significantly worse than that of high expression group.  It is not possible to obtain these two pairs of survival curves by dichotomising the same group of 54 patients by two different criteria. For instance, from 50 months on, both half-groups in 1D have a higher survival rate than the half-groups of 3E. Up to about 30 months, the half-groups of 3E have a higher survival rate. About the 32-month point, there is a death in 3E but not in 1D, and vice versa at the 38-month point. This is a recurring problem in this *oeuvre*. See, for instance, Figs 1C, 3D from [Zheng et al (2019)] .  , 
 Fig 3F.  qRT-PCR shows a significant negative correlation between the expression of LncRNA LINP1 and miR-491-3p in PCa tissues .  For comparison: *[left]* Fig 3C from [Liu et al (2019)] .  A significant negative correlation was found between microRNA-106a expression and DAX-1 expression in BC tissues. *[right]* Fig 4D from [Wu et al (2018)] .  A negative correlation was found between LINP1 and p53 in tumor tissues .  Many, many other versions of the same scatterplot within this *oeuvre*. , 
 Fig 1C.  qRT-PCR is used to detect the expression level of LncRNA LINP1 in PCa tissues with or without lymph node metastasis . Cases are present when the group is dichotomised by distant metastasis, but absent when dichotomised by lymph-node metastasis.  , 
 Fig 3 again:  An overlay of 20 correlation scatterplots from other papers (all based on the same spreadsheet), emphasising the points frequently occurring between them.  They include the four shown in  a small collage of the plots (h t [Elisabeth Bik] ):  ,