To detect the effect of Yanlu Rukang on the proliferation and apoptosis of breast cancer cells and explore its molecular mechanism.

Two breast cancer cell lines (MCF-7, MDA-MB-231) were treated with 0, 1, 2, 5 mg/L Yanlu Rukang solution. Then the cell counting kit-8 (CCK-8) was used to detect the optical density at 490 nm wavelength. The plate cloning experiment was performed to evaluate the proliferation of breast cancer cells, flow cytometry to evaluate the apoptosis of breast cancer cells, and Western blot to detect the expression of the related proteins, including cleaved poly ADP-ribose polymerase (cleaved PARP), phosphorylated signal transduction and transcriptionactivator 3 (p-STAT3), phosphorylated protein kinase B (p-AKT) and phosphorylated mitogen-activated protein kinase kinase(p-MEK). With normal distribution and homogeneity of variance, the parameters including the optical density, clone number, apoptosis rate and relative expression of each protein were expressed as ±s, and compared among groups using analysis of variance. The pairwise comparison was conducted using the LSD-t test.

In breast cancer cell lines MCF-7 and MDA-MB-231, the optical density presented a significant difference among four groups (0, 1, 2, 5 mg/L Yanlu Rukang group) (F=43.187, 28.163, both P<0.001), and all pairwise comparisons indicated a significant difference (all P<0.050). The number of cell clones presented a significant difference among four groups in MCF-7 and MDA-MB-231 cells (F=62.928, 48.975, both P<0.001). In MCF-7 cells, there was no significant difference in the number of cell clones between the 1 mg/L Yanlu Rukang group and the 2 mg/L Yanlu Rukang group (P=0.082), while other pairwise comparisons showed a significant difference (all P<0.050). The apoptosis rate of MCF-7 cells was (0.67 ± 0.05)%, (6.84 ± 0.35)%, (12.34 ± 0.58) % and (19.09 ± 1.04)% in 0, 1, 2, 5 mg/L Yanlu Rukang group, respectively, indicating a significant difference (F=802.097, P<0.050). The apoptosis rate of MDA-MB-231 cells was (0.49 ± 0.06)%, (6.65 ± 0.35)%, (13.06 ± 0.72)% and (15.42 ± 0.70)% in 0, 1, 2, 5 mg/L Yanlu Rukang group, indicating a significant difference (F=795.239, P<0.050). All pairwise comparisons showed a significant difference in the apoptosis rate (all P<0.050). Western blot results showed that in breast cancer MCF-7 cells, the relative expression of p-STAT3 was 0.193 ± 0.015, 0.133 ± 0.006, 0.092 ± 0.003 and 0.043 ± 0.002 in 0, 1, 2, 5 mg/L Yanlu Rukang group, respectively; the relative expression of p-AKT was 0.257 ± 0.015, 0.143 ± 0.006, 0.089 ± 0.004 and 0.044 ± 0.003, respectively; the expression of p-MEK was 0.760 ± 0.020, 0.563 ± 0.030, 0.343 ± 0.021 and 0.183 ± 0.031, respectively. The expressions of three proteins presented a significant difference among four groups (F=174.771, 353.658, 282.679; all P<0.001), and all pairwise comparisons showed a significant difference (all P<0.050). In breast cancer MDA-MB-231 cells, the relative expression of p-STAT3 was 0.173 ± 0.015, 0.150 ± 0.010, 0.123 ± 0.006 and 0.069 ± 0.003 in 0, 1, 2, and 5 mg/L Yanlu Rukang group, respectively; the relative expression of p-AKT was 0.250 ± 0.010, 0.200 ± 0.010, 0.150 ± 0.010 and 0.090 ± 0.010, respectively; the relative expression of p-MEK was 0.273 ± 0.006, 0.240 ± 0.010, 0.137 ± 0.015 and 0.086 ± 0.003, respectively. The expressions of three proteins presented a significant difference among four groups (F=64.297, 140.750, 245.790; all P<0.001); except one pair comparison (1 mg/L group vs 0 mg/L group, P=0.090), other pairwise comparisons showed a significant difference (all P<0.050).

Yanlu Rukang can inhibit the proliferation and promote the apoptosis of breast cancer cells, which may be related to the signaling pathways of JAK/STAT3, PI3K/AKT and MAPK.