Retracted : Triptolide inhibits the proliferation and migration of medulloblastoma Daoy cells by upregulation of microRNA‚Ä?38
Authors: Hui Li
Haifang Zhang
Ang Ge
Zhenguo Liu
Shuxia Liu
Enyu Guo
Zhiping Chen
Journal: Journal of Cellular Biochemistry (2018)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: cell proliferation; medulloblastoma; microRNA-138 (miR-138); notch signaling pathway; phosphatidylinositol 3-kinase (PI3K)/protein kinase 3 (AKT) signaling pathway
Affiliations: Department of Pediatrics, Jining No. 1 People's Hospital, Jining, Shandong, China.

Abstract:  Medulloblastoma is a primitive neuroectodermal-derived brain tumor and the most common malignant brain tumor in children. Triptolide (TPL) is the major active component extracted from Tripterygium wilfordii Hook F. This study aimed to explore the effects of TPL on medulloblastoma cell proliferation, migration, and apoptosis, as well as the underlying possible molecular mechanism. Viability, proliferation, and apoptosis of Daoy cells were measured using cell counting kit-8 assay, 5-bromo-2'-deoxyuridine incorporation assay, and Guava Nexin assay, respectively. Cell migration was detected using two-chamber transwell assay and wound healing assay. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to determine the relative expression of microRNA-138 (miR-138) in Daoy cells. Cell transfection was used to change the expression of miR-138 in cells. Western blot analysis was used to analyze the expression of key factors involved in cell apoptosis, cell migration, the phosphatidylinositol 3-kinase (PI3K)/protein kinase 3 (AKT) pathway, and the Notch pathway in Daoy cells. We found that TPL significantly inhibited the viability, proliferation, and migration of Daoy cells but promoted Daoy cell apoptosis. The expression levels of matrix metalloproteinases (MMP)-2 and MMP-9 after TPL treatment were decreased. The expression of miR-138 in Daoy cells after TPL treatment was increased. Suppression of miR-138 obviously reversed the TPL-induced Daoy cell proliferation, migration inhibition, and cell apoptosis enhancement, as well as the inactivation of the PI3K/AKT and Notch pathways. Cyclin-dependent kinase 6 (CDK6) was a direct target gene of miR-138, which might be involved in the antitumor effects of TPL on Daoy cells. In conclusion, our study verified that TPL exerted anticancer effects on medulloblastoma cells possibly via upregulating miR-138 and inactivating the PI3K/AKT and Notch pathways. 

Retracted: Yes

PubPeer comments:
 Many of the Western immunoblots in this paper seem to have backgrounds with patterns that are apparently repeated. Examples are shown for Figure 1, 2, 4 and 5.   , 
 Besides these issues with the images, the general concept of this paper is very strange. Triptolide is an inhibitor of RNA polymerase II initiation, I find it very hard to believe that this compound works through regulation of any specific gene. It will shut down mRNA production by the cell and this will lead to massive deregulation of cellular function. , 
 If the corresponding author opts for  RosettajKirkland3814 as an email address, this camphor-leafed waxy plant is in no position to judge, but it has the disadvantage that Gmail addresses are apparently not accessible in mainland China, so these requests for clarification will not get through.  , 
 Fig 2A. Transwell migration assay.  The TPL panel has also appeared in Figs 4D E and 3E of [Yi et al (2019)]  2H and 4E from [Lv et al (2019)] ...  3G from [Sun et al (2019)] .  Different identifications (and authors) each time. The papermill is parsimonious. , 
 This paper belongs to a set of over 400 papers (as per February 2020) that share very similar Western blots with tadpole-like shaped bands, the same background pattern, and striking similarities in title structures, paper layout, bar graph design, and - in a subset - flow cytometry panels. Despite these similarities, these papers are authored by researchers from different departments and institutes, with almost no overlap in authors. The list of these papers is available here: https: docs.google.com spreadsheets d 1KXqTAyl4j-jVorFPMD2XRpr76LcIKJ0CVyIvRj0exYQ edit?usp=sharing A more detailed description of this set of papers, suspected to all be generated by a common source, a paper mill , can be found here: * https: forbetterscience.com 2020 01 24 the-full-service-paper-mill-and-its-chinese-customers (January 2020) * https: scienceintegritydigest.com 2020 02 21 the-tadpole-paper-mill (February 2020) The same paper mill has been described in these papers: * Jana Christopher - Systematic fabrication of scientific images revealed - FEBS Letters (2018) - https: febs.onlinelibrary.wiley.com doi full 10.1002 1873-3468.13201 * Jennifer A Byrne and Jana Christopher - Digital magic, or the dark arts of the 21st centuryu2014how can journals and peer reviewers detect manuscripts and publications from paper mills? - FEBS Letters (2020) - https: febs.onlinelibrary.wiley.com doi full 10.1002 1873-3468.13747 , 
 Retracted [9 June 2021] . -------------------------------------- The above article, published online on 28 August 2018 in Wiley Online Library , has been retracted by agreement between the journal s Editor in Chief, Prof. Dr. Christian Behl, and Wiley Periodicals LLC. The retraction has been agreed following an investigation based on allegations raised by a third party. Several flaws and inconsistencies between results presented and experimental methods described were found, the editors consider the conclusions of this article to be invalid. The authors collaborated in the investigation initially, but were not available for a final confirmation of the retraction. ,