Authors retract prostate cancer-grape seed compound paper for figure presentation error
Here’s the notice for “Proanthocyanidins from grape seeds inhibit expression of matrix metalloproteinases in human prostate carcinoma cells, which is associated with the inhibition of activation of MAPK and NFκB”:
Due to an error of the presentation of data in figure 2 of this article, the authors have requested it be retracted from the journal.
The abstract, as originally published online, read: Prostate cancer (PCA) is the second most frequently diagnosed and leading cause of cancer-related deaths in men in the USA. The recognition that matrix metalloproteinases (MMPs) facilitate tumor cell invasion and metastasis of PCA has led to the development of MMP inhibitors as cancer therapeutic agents. As part of our efforts to develop newer and effective chemopreventive agents for PCA, we evaluated the effect of proanthocyanidins from grape seeds (GSP) on metastasis-specific MMP-2 and -9 in human prostate carcinoma DU145 cells by employing western blot and gelatinolytic zymography. Treatment of GSP dose-dependently inhibited cell proliferation (15–100% by 5–80 mg/ml of GSP), viability (30–80% by 20–80 mg/ml of GSP) and fibroblast conditioned medium (FCM)-induced expression of MMP-2 and -9 in DU145 cells. Since the signaling cascade of mitogen-activated protein kinases (MAPK) have been shown to regulate the expression of MMPs in tumor cells, we found that the treatment of DU145 cells with GSP (20–80 mg/ml) resulted in marked inhibition of FCM-induced phosphorylation of extracellular signal regulated kinase (ERK)1/2 and p38 but had little effect on c-Jun N-terminal kinase under similar experimental conditions. GSP treatment (20–80 mg/ml) to DU145 cells also dose-dependently inhibited FCM-induced activation of NFkB concomitantly with inhibition of MMP-2 and -9 expression in the same system. Additionally, the treatment of inhibitors of MEK (PD98059) and p38 (SB203580) to DU145 cells resulted in the reduction of FCM-induced phosphorylation of ERK1/2 and p38 concomitantly marked reduction in MMP-2 and -9 expressions. In further studies, treatment of androgen-sensitive LNCaP cells with a synthetic androgen R1881, resulted in an increase of MMP-2 and -9, which were completely abrogated in the presence of GSP (20–60 mg/ml). These data suggest that inhibition of metastasis-specific MMPs in tumor cells by GSP is associated with the inhibition of activation of MAPK and NFkB pathways, and thus provides the molecular basis for the development of GSP as a novel chemopreventive agent for both androgen-sensitive and -insensitive prostate cancer therapies.
Curtis C. Harris
The paper has been cited 69 times, according to Thomson Scientific’s Web of Knowledge.
Oxford University Press (OUP), the publishers of Carcinogenesis, tells Retraction Watch that a reader alerted Harris to potential issues with Figure 2 of the paper. Harris and two other scientists looked at the evidence, and decided there was enough to ask the authors to explain what looked like potential image manipulation. The journal then followed Committee on Publication Ethics (COPE) recommendations and contacted the corresponding author, Santosh Katiyar of the University of Alabama.
…responded in reasonable detail agreeing that there had been ‘an error in presentation of data [in figure 2]’ and requested that the paper be retracted. Carcinogenesis retracted the paper.
felt the answer was satisfactory and the Journal did not contact the author’s institution to request any further investigation.
OUP said it is not aware of any investigation by the University of Alabama. We’ve contacted Katiyar for comment, and will update with anything we hear back.