RETRACTED ARTICLE: Critical role of CCDC6 in the neoplastic growth of testicular germ cell tumors
Authors: Gennaro Ilardi
Angela Celetti
Stefania Staibano
Alfredo Fusco
Francesco Morra
Francesco Merolla
Chiara Luise
Vincenza Leone
Francesco Esposito
Maria Siano
Renato Franco
Paolo Chieffi
Journal: BMC Cancer (2013)
Discipline: CLINICAL MEDICINE
Keywords: DNA damage response; testicular germ cell tumors; CCDC6; ATM kinase; apoptosis
Affiliations: Istituto di Endocrinologia ed Oncologia Sperimentale, CNRz, via S Pansini, 5, Naples 80131, Italy. .

Abstract:  Background: DNA damage response has been clearly described as an anti-cancer barrier in early human tumorigenesis. Moreover, interestingly, testicular germ cell tumors (TGCTs) have been reported to lack the DNA Damage Response (DDR) pathway activation. CCDC6 is a pro-apoptotic phosphoprotein substrate of the kinase ataxia telangectasia mutated (ATM) able to sustain DNA damage checkpoint in response to genotoxic stress and is commonly rearranged in malignancies upon fusion with different partners. In our study we sought to determine whether CCDC6 could have a role in the patho-genesis of testicular germ cell tumors. Methods: To achieve this aim, analysis for CCDC6 expression has been evaluated on serial sections of the mouse testis by immunohistochemistry and on separate populations of murine testicular cells by western blot. Next, the resistance to DNA damage-induced apoptosis and the production of reactive oxygen species has been investigated in GC1 cells, derived from immortalized type B murine germ cells, following CCDC6 silencing. Finally, the CCDC6 expression in normal human testicular cells, in Intratubular Germ Cell Neoplasia Unclassified (IGCNU), in a large series of male germ cell tumours and in the unique human seminoma TCam2 cell line has been evaluated by immunohistochemistry and by Western Blot analyses. Results: The analysis of the CCDC6 expression revealed its presence in Sertoli cells and in spermatogonial cells. CCDC6 loss was the most consistent feature among the primary tumours and TCam2 cells. Interestingly, following treatment with low doses of H₂O₂, the silencing of CCDC6 in GC1 cells caused a decrease in the oxidized form of cytochrome c and low detection of Bad, PARP-1 and Caspase 3 proteins. Moreover, in the silenced cells, upon oxidative damage, the cell viability was protected, the γH2AX activation was impaired and the Reactive Oxygen Species (ROS) release was decreased. Conclusions: Therefore, our results suggest that the loss of CCDC6 could aid the spermatogonial cells to be part of a pro-survival pathway that helps to evade the toxic effects of endogenous oxidants and contributes to testicular neoplastic growth. 

Retracted: Yes

PubPeer comments:
 If I may plagiarise [Elisabeth M. Bik] : *The Western blots and other figures in this paper have an interesting layout that appears to be shared with many other papers, [...] The list of these papers is available here: https: docs.google.com spreadsheets d 1KXqTAyl4j-jVorFPMD2XRpr76LcIKJ0CVyIvRj0exYQ edit?usp=sharing* *In almost all papers, Western blot panels within the same figure, and across figures and papers, appear to share the same background, while the bands are regularly spaced, all have similar rounded edges without the usual smudges and specks, and with some bands showing a recognizable  jumping sardine shape.* *Also in almost all papers, bar graphs show a characteristic layout with bars in solid shades of grey, and the left most bar in black, as well as double-edged error bars. Many papers have  cell viability and  apoptotic cells graphs.* *In some of these papers, including this one, flow cytometry plot show a unnaturally dense and well defined  hairball of events in Q3 with a few regularly spaced events in Q1 and Q2.* In this case the FACS apoptosis plots are Figures 3G, 5G, 6I. It is easy to see that the 3rd quadrants of the 8 panels of 5G are variants of the same basic hairball, slightly customised by stippling with additional points. ![file] ![file] The 3rd quadrants of the 20 panels of 3G, 6I show equally little variation. Annotating them is left as an exercise for the reader. ![file] ![file] ,