Effect of Qiyu Sanlong Decoction in Inhibiting Growth of Lung Cancer by Regulating Expressions of Beclin1, Atg5 and LC3B / 中国实验方剂学杂志

ABSTRACT

Objective:To study the effect of Qiyu Sanlong decoction on the growth of subcutaneous tumor in lung cancer mice and the expressions of key autophagy molecule, yeast Atg6 homologous (Beclin1), autophagy related genes5 (Atg5), and microtubule-associated protein1 light chain3 (LC3B). Method:Lewis lung carcinoma cells (LLC) were used to reproduce the lung cancer mice transplanted model. After the modeling, the mice were randomly divided into model group, Qiyu Sanlong decoction group, chemotherapy group and combination group, with 18 transplanted mice in each group. In model group, mice were fed with 0.9% saline 20 mL·kg-1 daily. In Qiyu Sanlong decoction group, mice were fed with Qiyu Sanlong decoction 80.48 g·kg-1 daily. The chemotherapy group was intraperitoneally injected with 0.4 mL cisplatin solution (DDP) at the 1st, 3rd and 5th day. The combination group was orally given the drugs at the concentration of 80.48 g·kg-1, and 0.4 mL DDP solution was intraperitoneally injected at the 1st, 3rd and 5th day. After 21 days of continuous treatment, tumor tissue was exfoliated and weighed, and the tumor inhibition rate was calculated. Hematoxylin-eosin (HE) staining was used to observe the histological changes of tumor. The expressions and localizations of Beclin1 and LC3B in tumor tissues were detected by immunohistochemical staining. Protein expressions of Beclin1, Atg5, LC3B-Ⅰand LC3B-Ⅱ were determined by Western blot, and the ratio of LC3B-Ⅱ/LC3B-Ⅰ was calculated. The transcription levels of Beclin1, Atg5 mRNA in tumor tissues were detected by Real-time PCR. Result:Qiyu Sanlong decoction had a mild inhibitory effect on transplanted tumor, with an inhibitory rate of 31.2%. Under microscope, patchy necrotic tumor cells were observed in the tumor tissues of Qiyu Sanlong decoction group. Immunohistochemical staining and Western blot analysis showed that Qiyu Sanlong decoction could up-regulate the expressions of Beclin1, Atg5 and LC3B protein (P<0.01), and promote the conversion from LC3B-Ⅰ into LC3-Ⅱ compared with the model group. Real-time PCR results showed that Qiyu Sanlong decoction could promote the transcription of Beclin1 mRNA and Atg5 mRNA compared with the model group (P<0.01). Conclusion:Qiyu Sanlong decoction has a mild inhibitory effect on lung tumors, and its mechanism may be related to up-regulating the expressions of autophagy key proteins Beclin1, Atg5 and LC3B, and promoting the conversion from LC3B-Ⅰ to LC3B-Ⅱ.