Correction to: Acta Pharmacol Sin 2015;36:1085–98, https://doi.org/10.1038/aps.2015.42, published online 03 August 2015

The authors regretted to find the mis-representative images in Fig. 3a, c and Fig. 4a, c when re-read our previously published article Synergistic suppression of human breast cancer cells by combination of plumbagin and zoledronic acid In vitro (https://doi.org/10.1038/aps.2015.42) in the journal of Acta Pharmacologica Sinica. The first mistake occurred due to the careless compilation when the authors tried to show the synergistic effect against tumor during figure presentation process. The second mistake occurred because the authors carelessly mixed up representative pictures of different magnification during microscopic observation of breast cancer cells after drugs treatments. The right Fig. 3a, c and Fig. 4a, c were provided below. Despite that this correction does not affect the results and conclusions of the aforementioned paper, all the authors still consent on the correction of this negligence. We apologize to the Editor and the readership of the journal for any inconvenience caused. Your thoughtful understanding is highly appreciated.

Fig. 3
figure 1

Cell apoptosis induced in MDA-MB-231SArfp cells by plumbagin (PL) and zoledronic acid (ZA) alone or in combination. a MDA-MB-231SArfp cells were incubated with the indicated concentrations of PL and ZA alone for 24 h, followed by annexin V-FITC/PI double staining to evaluate apoptotic cell death. c Similar procedures were performed in MDA-MB-231SArfp cells after combined treatment with PL and ZA for 24 h

Fig. 4
figure 2

Effects of plumbagin (PL) and zoledronic acid (ZA) alone or in combination on MDA-MB-231SArfp cell migration. a In vitro evaluation of MDA-MB-231SArfp cell migration after PL and ZA treatment alone. c Combined administration of PL and ZA significantly enhances the inhibition of tumor cell metastasis compared with individual treatment