Effect of Panax Notoginseng Saponins on Breast Cancer Cell Line 4T1 in Tumor-bearing Mice Through MEKK1/SEK1/JNK1/AP-1 Pathway / 中国实验方剂学杂志

Objective:To explore the potential mechanisms of Panax Notoginseng Saponins （PNS） on growth inhibition of breast cancer cell line 4T1 in tumor-bearing mice by investigating the mitogen-activated protein kinase kinase kinase 1 （MEKK1）/stress activated protein kinase （SAPK）/extracellular regulated protein kinases （Erk） Kinase （SEK1）/c-Jun N-terminal kinase 1 （JNK1）/activator protein-1 （AP-1） signaling pathways. Method:The 4T1 breast cancer mice model was established. Forty-eight mice with successful modeled and randomly divided into the low， medium and high-dose PNS groups （10， 20， 40 mg·kg-1） and the model control group （12 mice in each group）. The PNS groups received intraperitoneal injection with dosage of 10 mL·kg-1， while the controlled group was given the same dosage of saline. After administration with PNS for 28 days， tumor tissues were isolated， weighed， sliced and homogenized. Tumor cell apoptosis was detected by TdT mediated-dUTP nick end labeling （TUNEL） staining. The mRNA expressions of MEKK1， SEK1， JNK1 and AP-1 in tumor tissue were detected by Real-time polymerase chain reaction（Real-time PCR）. The protein expressions of MEKK1， SEK1， JNK1 and AP-1 in tumor tissue were detected by immunofluorescence staining and Western blot. Result:Compared with model group， the tumor weights of medium-dose and high-dose PNS groups were decreased significantly （P<0.05）. TUNEL staining showed that the number of apoptotic tumor cells increased with the rise of dosage of PNS （P<0.05）. The medium-dose and high-dose PNS groups showed a significant increase in the mRNA expressions of MEKK1， SEK1， JNK1 and AP-1 as well as the protein expressions of MEKK1， SEK1， JNK1 and AP-1 in tumor tissues （P<0.05）， with statistically significant differences （P<0.05）. Conclusion:PNS could inhibit the tumor growth of breast cancer cell line 4T1 in tumor-bearing mice， which may be related to the activation of MEKK1/SEK1/JNK1/AP-1 signaling pathways.

Effect of Shaoyaotang on Expressions of AP-1 and TNF-α in Colon of Rats with Hygrothermal Ulcerative Colitis / 中国实验方剂学杂志

Objective: To observe the effect of Shaoyaotang on mRNA and protein expressions of colon tissue activated protein-1 (AP-1) and tumor necrosis factor-α (TNF-α) of hot and humid-type intrinsic ulcerative colitis (UC) model in rats, in order to explore the mechanism of action of herbaceous peony decoction in the treatment of UC. Method: Totally 60 Wistar rats were randomly divided into blank group, model group, SASP group, and low, medium and high-dose Shaoyaotang groups. The damp-heat intrinsic UC rat model was replicated based on integrated disease and syndrome, namely, high-fat and high-sugar spicy food and immune complex method combined with 2,4,6-trinitrobenzene sulfolnic acid (TNBS) and ethanol complex method. After the successful modeling, low, medium and high-dose Shaoyaotang (6, 12, 24 g·kg-1) was given by gavage, and 1 g·kg-1 dose of salazol sulfadiazine was given to by gavage. The blank group was given constant volume normal saline for 21 d. Real-time fluorescence quantitative polymerase chain reaction(Real-time PCR) was used to detect mRNA expressions of AP-1 and TNF-α in colon tissues, and Western blot was used to detect protein expressions of AP-1 and TNF-α in colon tissues. Result: Compared with the blank group, relative mRNA and protein expressions of AP-1, TNF-α in the model group were significantly increased (Pα in the treatment groups were significantly decreased (PConclusion: Shaoyaotang can inhibit the expression of TNF-α and stimulate AP-1 protein expression in rats with damp-heat UC.

The Heterochromatin-1 Phosphorylation Contributes to TPA-Induced AP-1 Expression

Activator protein-1 (AP-1) is an inducible transcription factor that contributes to the generation of chronic inflammation in response to oxidative and electrophilic stress. Previous studies have demonstrated that the PI3K/Akt1 pathway plays an important role in the transcriptional regulation of AP-1 expression. Although the histone post-translational modifications (PTMs) are assumed to affect the AP-1 transcriptional regulation by the PI3K/Akt pathway, the detailed mechanisms are completely unknown. In the present study, we show that heterochromatin 1 gamma (HP1gamma) plays a negative role in TPA-induced c-Jun and c-Fos expression. We show that TPA-induced Akt1 directly phosphorylates HP1gamma, abrogates its suppressive function and increases the interaction between histone H3 and 14-3-3epsilon. Collectively, these our data illustrate that the activation of PI3K/Akt pathway may play a permissive role in the recruitment of histone readers or other coactivators on the chromatin, thereby affecting the degree of AP-1 transcription.