Carcinogenesis is retracting the following paper following a joint research misconduct investigation by the Birmingham VA Medical Center and the University of Alabama at Birmingham, AL, USA.
Singh, T. et al. (2011) Berberine, an isoquinoline alkaloid, inhibits melanoma cancer cell migration by reducing the expressions of cyclooxygenase-2, prostaglandin E(2) and prostaglandin E(2) receptors. Carcinogenesis, 32(1), 86–92.
There are two main concerns. First, the beta actin controls for experimental data displayed in Figures 3E and 5B are identical. However, the experimental treatment for data shown in Figure 3 (increasing concentrations of berberine with or without TPA (Figure 3E) or PGE2 (Figure 5B) are different. Thus, there is an ambiguous identification of the control conditions for both experiments. There are no original data or records available with which to confirm the experimental results. Thus, the conclusions of the paper could not be substantiated by the available data.
Second, Figure 1B of this paper contains a photomicrograph of Hs2894t cells treated with 10 ug/ml of epigallo-catchin-3-gallate, an extract of green tea. This image is identical to Figure 2A of another paper (Singh, T. and S.K. Katiyar, Green tea catechins reduce invasive potential of human melanoma cells by targeting COX-2, PGE2 receptors and epithelial-to-mesenchymal transition. PLoS One, 2011. 6(10): p. e25224); however, the PLoS One image is of control Hs294t cells receiving 0 uM Berberine. Examination of the two panels at high magnification indicated that the same micrograph was used in each figure but labeled as belonging to different experimental groups. The lack of available original data and records preclude an unambiguous identification of the cell type and the experimental treatment in either paper.
This retraction is based on the unavailability of original data and records, the lack of replicate experiments that validate the published findings, and the ambiguous identification of many of the samples, treatments and controls.