Bladder cancer (BC) is the most common cancer of the urinary system. Despite advances in diagnosis and therapy, the prognosis is still poor because of recurrence and metastasis. Epithelial-mesenchymal transition (EMT) is considered to play an important role in the invasion and metastasis of BC. Grape seed proanthocyanidins (GSPs) exhibit chemopreventive and chemotherapeutic activities against several types of cancer. However, their effects and underlying mechanisms on the invasive potential of BC remain unclear. In this study, we found that GSPs inhibited migration, invasion, and MMP-2/-9 secretion of both T24 and 5637 bladder cancer cells at noncytotoxic concentrations. We also discovered that 5637 cells were more suitable than T24 cells for the EMT study. Further study showed that GSPs inhibited EMT by reversing the TGF-β-induced morphological change and upregulation of mesenchymal markers N-cadherin, vimentin, and Slug as well as downregulation of epithelial markers E-cadherin and ZO-1 in 5637 cells. GSPs also inhibited TGF-β-induced phosphorylation of Smad2/3, Akt, Erk, and p38 in 5637 cells without affecting the expression of total Smad2/3, Akt, Erk, and p38. Taken together, the results of the present study demonstrate that GSPs effectively inhibit the migration and invasion of BC cells by reversing EMT through suppression of the TGF-β signaling pathway, which indicates that GSPs could be developed as a potential chemopreventive and therapeutic agent against bladder cancer.

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Background: Many previous studies have analyzed the status of retracted publications from different perspectives, but so far no study has focused on systematic reviews (SRs). The purpose of this study is to analyze the retraction status and reasons of non-Cochrane SRs in the field of medicine. Methods: We searched MEDLINE and Embase from their inception to April 18, 2020, as well as Retraction Watch Database and Google Scholar with no language restriction to find non-Cochrane SRs that were retracted for any reason. Two reviewers independently screened and extracted data. We describe the characteristic and reasons of retraction and the duration from publication to retraction. Results: We identified 150 non-Cochrane SRs in medicine retracted between 2004 and 2020. The majority of retracted SRs were led by authors from China and affiliated with hospitals. Most SRs were published in journals with an impact factor ≤3, and in journal ranked in the third quarter. The largest proportion of retraction notices were issued by the publisher and editor(s) jointly; seven did not report this information. Fraudulent peer-review was the most common reason for retraction, followed by unreliable data meaning errors in study selection or data analysis. The median time between publication and retraction was 14.0 months. SRs retracted due to research misconduct took longer to retract than SRs retracted because of honest error. Conclusions: The situation with retracted SRs is critical globally, and in particular in China. The most common reasons for retraction are fraudulent peer-review and unreliable data, and in most cases the study is retracted more than a year after publication. Efforts should be made to improve the process of peer review and adherence to the COPE retraction guidance, while at the same time authors should strengthen their skills in SR methodology. Keywords: Retraction; Systematic review; non-Cochrane; Research ethics.

BackgroundMany previous studies have analyzed the status of retracted publications from different perspectives, but so far no study has focused on systematic reviews (SRs). The purpose of this study is to analyze the retraction status and reasons of non-Cochrane SRs in medicine. MethodsWe searched MEDLINE and Embase from their inception until April 18, 2020, as well as Retraction Watch Database and Google Scholar with no language restriction to find non-Cochrane SRs that were retracted for any reason. Two reviewers independently screened and extracted data. We described the characteristic and reasons of retraction and the duration from publication to retraction.ResultsWe identified 150 non-Cochrane SRs in medicine retracted between 2004 and 2020. The majority of retracted SRs were led by authors from China (n=113, 75.3%) and affiliated with hospitals (n=106, 70.7%). Most SRs were published in journals with an impact factor ≤3 (n=85, 56.7%). The largest proportion of retraction notices were issued by the publisher and editor(s) jointly (n=60, 40.0%); seven did not report this information. Fraudulent peer-review (n=61, 37.9%) was the most common reason for retraction, followed by unreliable data (n=41, 25.5%) meaning errors in study selection or data analysis. The median time between publication and retraction was 14.0 months. SRs retracted due to research misconduct took longer to retract than SRs retracted because of honest error. ConclusionsThe situation with retracted SRs is critical worldwide, and in particular in China. The most common reasons for retraction are fraudulent peer-review and unreliable data, and in most cases the study is retracted more than a year after publication. Efforts should be made to improve the process of peer review and adherence to the COPE retraction guidance, and authors should strengthen their skills in SR methodology.