Effect of Yanghetang-containing Serum on Breast Cancer 4T1 Cells Based on MEK/ERK Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the effects of Yanghetang （YHT） on breast cancer 4T1 cells and their mitogen-activated protein kinase （MEK）/extracellular signal-regulated kinase （ERK） signaling pathway. MethodThe YHT-containing serum was prepared from SD rats. The rats were randomly assigned into a blank group （normal saline） and low-， medium-， and high-dose （5.8， 11.6， 23.2 g·kg-1， respectively） YHT groups. The serum containing 10% YHT in each group was mixed with 90% RMPI 1640 complete medium， and the mixture was used to interfere with the cells. Cell counting kit-8 （CCK-8） method was used to detect the proliferation of the 4T1 cells treated with YHT for 24， 48， 72 h. The apoptosis， migration， and invasion of 4T1 cells were detected by flow cytometry， scratch test， and Transwell assay， respectively. Western blot was employed to determine the expression levels of MEK1/2， phosphorylation （p）-MEK1/2， ERK1/2， p-ERK1/2， and rat sarcoma virus （RAS） protein. ResultCompared with the blank group， the intervention with YHT-containing serum for 24， 48， and 72 h had significant inhibitory effect on 4T1 cell proliferation （P<0.05， P<0.01）. After intervention with YHT-containing serum for 48 h， the apoptosis rate of cells increased （P<0.01）. Compared with the blank group， the intervention with YHT for 24 h and 48 h decreased the healing ability of cells in the scratch test （P<0.01）. The invasive ability of cells treated with the low， medium， and high-dose YHT containing serum showed a decreasing trend （P<0.01）. Compared with the blank group， YHT-containing serum did not change the expression of MEK1/2 and ERK1/2 while down-regulating the expression of p-MEK1/2， p-ERK1/2， and RAS protein （P<0.01）. ConclusionYHT can inhibit the proliferation， migration， and invasion and promote the apoptosis of breast cancer 4T1 cells. In may promote the apoptosis by inhibiting the MEK/ERK signaling pathway and down-regulating the expression of p-MEK1/2， p-ERK1/2， and RAS protein.

Shikonin Affects Uterine Leiomyoma in Rats by Regulating ERK Signaling Pathway / 中国实验方剂学杂志

Objective:To investigate the effect of shikonin on uterine leiomyoma in rats and its molecular mechanism. Method:Sixty female SD rats， of SPF grade and weighing 200-250 g， were randomly divided into the control group， model group， low-， medium-， and high-dose （5， 10， 20 mg·kg^-1） shikonin groups， and mifepristone group. A rat model of uterine leiomyoma was established， and the changes in uterine wet weight， uterine coefficient， and smooth muscle thickness were detected after drug administration for four successive weeks. The pathological changes in uterine tissue were observed by hematoxylin-eosin （HE） staining. The contents of estrogen receptor （ER） and progesterone receptor （PR） in serum and uterus were measured by enzyme-linked immunosorbent assay （ELISA）， and the protein expression levels of ER， PR， phosphorylated extracellular signal-regulated kinase （p-ERK）， and ERK in the uterine tissue were assayed by Western blot. Result:Compared with the control group， the model group exhibited significantly increased uterine wet weight， uterine coefficient， and smooth muscle thickness （<italic>P</italic><0.01）， uterus deformity， focal smooth muscle cell necrosis and hyperplasia， neutrophil infiltration. elevated serum and uterine ER and PR （<italic>P</italic><0.01）， and up-regulated p-ERK protein expression in the uterine tissue （<italic>P</italic><0.01）. Compared with the model group， shikonin at the middle and high doses and mifepristone significantly reduced the uterine wet weight， uterine coefficient， and smooth muscle thickness （<italic>P</italic><0.01）， relieved the pathological changes in uterus，and lowered serum and uterine ER and PR， and down-regulated the p-ERK protein expression in the uterine tissue （<italic>P</italic><0.05）. In addition， the uterine wet weight， smooth muscle thickness， serum ER， and uterine PR and p-ERK protein expression in the low-dose shikonin group were significantly lower than those in the model group （<italic>P</italic><0.05）. Conclusion:Shikonin produces the anti-uterine leiomyoma activity possibly by inhibiting the activation of ERK pathway.

Total Saponins from Paris forrestii Reverse Multidrug Resistance of MCF-7/ADM Cells by Suppression of P-gp via ERK Signaling Pathway.

Our previous study demonstrated that the total saponins from Paris forristii (PCT3) had obvious inhibitory effect on the proliferation of adriamycin-resistant human breast adenocarcinoma cells (MCF-7/ADM), and this effect was significantly stronger than that in parental cells (MCF-7). This study was designed to test the reversal effect of PCT3 on MCF-7/ADM cells and to understand its mechanism of action. Results demonstrated that low cytotoxic concentrations of PCT3 (0.3, 1 and 3 µg/mL) reversed resistance of MCF-7/ADM cells to ADM, cisplatin (DDP) and 5-fluorouracil (5-FU), with reversal fold of 16.4, 19.5 and 31.7 for ADM, 1.6, 1.4 and 1.4 for DDP, 1.7, 1.8 and 5.6 for 5-FU, respectively. Moreover, PCT3 significantly increased the accumulation of ADM and Rhodamine 123 (Rh123) in MCF-7/ADM cells, suggesting that PCT3 may act by affecting the function of drug efflux pump P-glycoprotein (P-gp), which is encoded by MDR1 gene. Both MDR1 gene and P-gp protein expression was downregulated by PCT3 treatment. Further results demonstrated that p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathway was remarkably activated in MCF-7/ADM cells, inhibition of p38 or ERK attenuated P-gp expression. While, only the phosphorylation level of ERK was downregulated by PCT3, indicating that PCT3 sensitized P-gp overexpressed MCF-7/ADM cells to ADM via inhibition of ERK signaling pathway.