MicroRNA-9 suppresses the growth, migration, and invasion of malignant melanoma cells via targeting NRP1
Authors: Dan Xu
Quanyong He
Chengqun Luo
Xiaofeng Chen
Journal: OncoTargets and Therapy (2016)
Discipline: CLINICAL MEDICINE
Keywords: invasion; malignant melanoma; microRNA; migration; neuropilin1
Affiliations: Department of Plastic Surgery, Third Xiangya Hospital of Central South University., Department of Neurosurgery, Brain Hospital of Hunan Province, Changsha, Hunan, People's Republic of China.

Abstract:  MicroRNAs (miRs) are a class of small noncoding RNAs that negatively regulate the gene expression by directly binding to the 3' untranslated region of their target mRNA, thus resulting in mRNA degradation or translational repression. miR-9 has recently been demonstrated to play a role in the development and progression of malignant melanoma (MM), but the regulatory mechanism of miR-9 in the malignant phenotypes of MM still remains largely unknown. In this study, a total of 73 pairs of MM tissues and adjacent normal tissues were collected. Real-time reverse transcription polymerase chain reaction and Western blot were used to detect the mRNA and protein expression of miR-9. MTT assay, wound healing assay, and transwell assay were conducted to determine the cell proliferation, migration, and invasion. Luciferase reporter assay was used to determine the targeting relationship between miR-9 and NRP1. Our data demonstrated that miR-9 expression was significantly downregulated in MM tissues compared with that in adjacent normal tissues. The decreased miR-9 level was significantly associated with the tumor stage and metastasis of MM. We also found that the expression level of miR-9 was decreased in MM cell lines (G361, B16, A375, and HME1) compared with normal skin HACAT cells. Ectopic expression of miR-9 led to a significant decrease in the ability of proliferation, migration, and invasion in A375 cells. NRP1 was further identified as a direct target gene of miR-9, and the protein expression of NRP1 was negatively regulated by miR-9 in A375 cells. Furthermore, overexpression of NRP1 reversed the suppressive effects of miR-9 on the malignant phenotypes of A375 cells. In vivo study revealed that miR-9 overexpression decreased the tumor growth, while overexpression of NRP1 increased MM growth. In summary, our findings suggest that the miR-9/NRP1 axis may serve as a potential target for the treatment of MM. 

Retracted: No

PubPeer comments:
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 Figs 2D, 4D.  Transwell assay was used to measure the ability of cell invasion in A375 cells transfected with miR-NC or miR-9 mimic, or the untreated cells ;  Transwell assay was used to measure the ability of cell invasion in A375 cells transfected with miR-9 alone or cotransfected with miR-9 mimic and pcDNA3.1-NRP1 plasmid . ![file] I set up a spreadsheet to include the various papers using this versatile suite of Transwell images to represent all possible combinations of cell-lines and treatments. This is the 34th manifestation. For comparison: Fig 3 C D from [Zhang et al (2016)] .  Transwell assay were performed to examine the migratory and invasive capacities of Saos-2 and U2OS cells transfected with miR-205 mimic or miR-negative control (NC) mimic , and Fig 7C D,  Transwell assay were performed to examine cell migration and invasion of MG63 or U2OS cells transfected with miR-205 mimic, or co-transfected with miR-205 mimic and RUNX2 plasmid . ![] Figs 4D, 6D from [Xia et al (2016)] . ![] ,