Fig. 1

Cantharidin selectively inhibits EGFR-overexpressed cells proliferation. A Chemical structure of cantharidin. B Images of tumors excised from five nude mice at 12 days after intraperitoneal injection of saline solution or cantharidin in 4T1 homograft tumors. C Effects of cantharidin treatment on the masses of 4T1 tumors. D Volume changes of 4T1 tumors were measured every day. E Effects of cantharidin on cell proliferation in indicated human breast cancer cells and human normal breast epithelial cells MCF-10 A. F Protein expression of EGFR in breast cancer cells BT474, T47D, MCF-7, MDA-MB-231 and MDA-MB-468. G Protein expression and quantification of EGFR in HEK293, HEK293/EGFR and A431 cells. H Effects of cantharidin on cell proliferation in HEK293, HEK293/EGFR and A431 cells. I The chromatograms of cantharidin (i, ii) and afatinib (iii, iv) on HEK293/CMC (i, iii) and EGFR/CMC (ii, iv) column. J Effects of cantharidin on the colony formation of MDA-MB-231 and MDA-MB-231 cells. The EGFR inhibitor gefitinib (6 µM) and afatinib (6 µM) were utilized as positive control drug. The colony formation (the upper line) and the individual colony (the lower line) (×200 magnification) were photographed. Data were expressed as mean ± SEM (n = 3), *p < 0.05, **p < 0.01, ***p < 0.001