Function of miR-212 as a tumor suppressor in thyroid cancer by targeting SIRT1
Authors: Lin Bai
Minglong Chen
Tongtong Wang
Dandan Li
Yantao Fu
Qian Xie
Qiang Wen
Journal: Oncology Reports (2017)
Discipline: CLINICAL MEDICINE
Keywords: miR-212; tumor suppressor; thyroid cancer; downregulation; lymph node metastasis
Affiliations: Department of Nuclear Medicine, China-Japan Union Hospital of Jilin University, Changchun, Jilin 13033, P.R. China., Department of Thyroid Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin 13033, P.R. China.

Abstract:  miR-212 as a tumor suppressor has been reported to be downregulated in multiple cancer cells lines and tumor tissues. However, its role in thyroid cancer has nor been investigated. Therefore, the present study aimed to investigate the role of miR-212 in human thyroid cancer and the underlying mechanisms. In the present study, we demonstrated that miR-212 expression was significantly decreased in thyroid cancer specimens and cell lines compared with adjacent normal tissues and normal thyroid cell lines. In addition, we demonstrated that miR-212 downrwegulation in thyroid cancer tissues was negatively associated with lymph node metastasis and advanced clinical stage. Functionally, ectopic expression of miR-212 by transfection with miR-212 mimic significantly inhibited proliferation, colony formation, migration and invasion in TPC-1 cells. In addition, Sirtuin 1 (SIRT1) was identified as a direct target of miR-212 and its expression was inversely correlated with miR-212 expression in thyroid cancer tissues. Overexpression of SIRT1 could effectively rescue miR-212 mimic-induced suppression of cell proliferation, migration and invasion in TPC-1 cells. In vivo, miR-212 overexpression significantly inhibited tumor growth in a nude mice model. In light of these findings, miR-212 may function as a tumor suppressor in thyroid cancer by targeting SIRT1. 

Retracted: Yes

PubPeer comments:
 Fig 6B.  Photographs of xenograft tumors. ![file] *[left]* Fig 6B from [Li et al (2018)] .  Tumor tissues were imaged after the mice were sacrificed . *[right]* Fig 3B from [Fei et al (2018)] .  Shown are images of xenograft tumors at 28 days post injection. ![file] UPDATE: Fig 7C from [Chen et al(2017)] .  Photographs of xenograft tumors isolated from miR-25 mimic and miR-Ctrl injected mice . ![] , 
 Fig 2E. Cell invasion  determined in TPC-1 cells after transfection with miR-212 mimic or miR-NC . ![file] No comment required. , 
 Fig 2E again. Cell invasion  determined in TPC-1 cells after transfection with miR-212 mimic or miR-NC . ![] Fig 3B from [Feng et al (2018)] .  Transwell invasion assay showed that downregulation of GACAT3 significantly decreased invasive ability of SGC-7901 cells. ![file] I have many questions. , 
 Retracted [24 August 2021] . ------------------------- Following the publication of this paper, it was drawn to the Editors attention by a concerned reader that the tumor images shown in Fig. 6B bore unexpected similarities to data appearing in different form in other articles by different authors. In addition, there were potential anomalies associated with the cell migration assay data shown in Fig. 2E. Owing to the fact that some of the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to *Oncology Reports*, the Editor has decided that this paper should be retracted from the Journal. The authors agree with the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused ,