Objective   To investigate the effects of ursolic acid on the expression of extracellular signal regulated kinase (ERK1)

C-Jun

C-Myc

Cyclin D1 in transplanted tumor of malignant glioblastoma cell line C6 in nude mice and the related mechanisms.     Methods   C6 glioblastoma cells were subcutaneously injected into nude mice to establish the subcutaneous model of glioblastoma in nude mice

and then the mouse models were divided into 3 groups: blank control group

ursolic acid group (50 mg·kg

-1

·d

-1

intra-abdominal injection

20 d)

PD98059 group (2 mg·kg

-1

·d

-1

intra-abdominal injection

7 d). Survival of nude mice

growth and histopathological changes of the tumors were observed. The expressions of ERK1

C-Jun

C-Myc

and Cyclin D1 in the tumor tissues and the expression of ERK1 mRNA in the tumor tissues were detected by immunohistochemical technique (IHC) and in suit hybridization (ISH)

respectively.     Results   Slow growth of the implanted tumor was found in ursolic acid group and PD98059 group. The mean volume and weight of tumors in the two groups were significantly smaller than those in the blank control group (P0.05). The expressions of ERK1

C-Jun

C-Myc

Cyclin D1

and ERK1 mRNA in ursolic acid group and PD98059 group were significantly lower than those in the control group (P0.05).    Conclusion   Ursolic acid can significantly inhibit the growth of the implanted glioma in nude mice through down-regulation of the expressions of ERK1

C-Jun

C-Myc

and Cyclin D1 of ERK signal transduction pathway.