OBJECTIVETo investigate the inhibitory effect of compound cantharides capsules on the proliferation of xenografts of human hepatocellular carcinoma HepG(2215) in mice and their mechanism of action.

METHODSOne hundred healthy Balb/c mice (5-week old, male:female 1:1) were used in this study. Mouse models of human HepG(2215) hepatocarcinoma were established. The tumor-bearing mice were divided into five groups randomly. The control group A received daily intragastric administration of physiologic saline. The intervention groups B1, B2 and B3 were treated with compound cantharides capsule in a dose of 12.5 mg×kg(-1)×d(-1), 25 mg×kg(-1)×d(-1) and 37.5 mg×kg(-1)×d(-1), respectively, for 10 consecutive days. The group C had intraperitoneal injection of cyclophosphamide (25 mg×kg(-1)×d(-1)) for 10 consecutive days. The mice were sacrificed after the completion of administration. The tumors were taken out, the tumor volume was measured, the inhibitory rate of body weight was calculated, and the serum AFP concentration and the level of HBV DNA were determined. The survival of each group mice was analyzed. The levels of mRNA expression of apoptosis-related genes were assayed by quantitative RT-PCR. Apoptosis in the tumor cells was assayed with TUNEL staining. Flow cytometry was used to detect the levels of CD3(+), CD19(+), CD4(+) and CD8(+), and microvessel density (MVD) of the tumors was assessed by immunohistochemistry.

RESULTSAfter completion of the treatment, the inhibition rate of tumor growth of the groups B1, B2 and B3 was 29.8%, 38.7% and 48.1%, respectively, and that of the group C was 52.4%, with a significant difference among the groups (P < 0.05). The median survival time of the groups A, B1, B2, B3 and C was (30.0 ± 3.2) days, (49.0 ± 5.1) days, (50.0 ± 5.2) days, (57.5 ± 6.5) days and (49.0 ± 4.7) days, respectively. The median survival time of the group B3 was significantly longer than that of other groups (P < 0.05). The serum AFP level in the groups A, B1, B2, B3 and C was (492.7 ± 48.5) ng/ml, (281.2 ± 25.6) ng/ml, (194.3 ± 18.7) ng/ml, (170.1 ± 15.8) ng/ml and (138.7 ± 12.5) ng/ml, respectively, indicating that it was significantly inhibited in the group C. The inhibition rate of HBV DNA replication of the groups B1, B2, B3 and C was (46.0 ± 5.1)%, (65.5 ± 6.9)%, (81.3 ± 7.8)% and (19.5 ± 2.1)%, respectively, showing that compound cantharides capsules inhibited HBV DNA replication in a dose-dependent manner. The apoptosis rate of the groups A, B1, B2, B3 and C was (0.27 ± 0.03)%, (7.18 ± 2.12)%, (9.17 ± 2.42)%, (11.27 ± 3.03)% and (5.44 ± 2.45)%, respectively, and that of the group B3 was significantly higher than that of the groups A, B1, B2 and C (P < 0.05). The expression level of bax mRNA was significantly higher than that of the group C (P < 0.05). The drug could significantly decrease the bcl-2 mRNA expression level, more remarkably along with the increasing dose of cantharides, and it was significantly lower than that in the group C (P < 0.05). The levels of CD4(+), CD8(+), CD3(+) and CD19(+) were significantly higher than that in the groups A and C (P < 0.05). The value of MVD of the group B3 was significantly lower that that of groups A and C (P < 0.05).

CONCLUSIONCompound cantharides capsules may inhibit the replication of HBV DNA in HepG(2215) cells, inducing apoptosis in the tumor cells, enhancing the immune function to inhibit the growth of liver cancer cells in mice, and significantly prolong the median survival time of tumor-bearing mice.