Figure 5.

Effects of trametinib on tumor growth against xenografted BC organoids in immunodeficient mice. Experimental schema of in vivo experiment (a). After BC organoid cells were subcutaneously injected into the back of SCID mice and tumors formed, trametinib and the vehicle was administered to the mice at the concentration of 1 mg kg⁻¹ for 4 weeks. Thereafter, the tumor volume was measured by clipper every week for 6 weeks (B, n = 6). Tumor tissues of each group was isolated and used for analysis. Comparison of tumor growth curve (b), size (c), and weight (d) between trametinib- or vehicle- administered mice. Results were expressed as mean ± S.E.M. ﹡P < .05 vs. vehicle. Representative H&E staining images of the tumor tissue sections from trametinib- or vehicle- administered mice (e). Scale bar: 200 μm. Confocal microscopy fluorescence images of apoptosis as determined by TUNEL staining of frozen sections of tumor tissues from trametinib-treated or vehicle- administered mice (f, n = 3). Sections treated with DNase I were used as a positive control. Scale bar: 50 μm. Expression level of CK5 in sections from dissected tumors of trametinib- or vehicle-administered mice as determined by confocal microscopy (g, scale bar: 50 μm). Expression level was quantified by counting the CK5-positive cells (h, n = 3). Results were expressed as mean ± S.E.M. ﹡P < .05 vs. vehicle