Inhibitory effects of TNP-470 in combination with BCNU on tumor growth of human glioblastoma xenografts

This study investigated the effect of TNP-470 in combination with carmustine (BCNU) on the growth of subcutaneously implanted human glioblastoma xenografts in nude mice. Human glioblastoma U-251 cells (1×10⁷) were injected into 24 nude mice subcutaneously. The tumor-bearing mice were randomly divided into 4 groups on the seventh day following tumor implantation: TNP-470 group, in which TNP-470 was given 30 mg/kg subcutaneously every other day 7 times; BCNU group, in which 20 mg/kg BCNU were injected into peritoneal cavity per 4 days 3 times; TNP-470 plus BCNU group, in which TNP-470 and BCNU were coadministered in the same manner as in the TNP-470 group and the BCNU group; control group, in which the mice were given 0.2 mL of the mixture including 3% ethanol, 5% acacia and 0.9% saline subcutaneously every other day 7 times. The tumor size and weights were measured. The tumor microvessel density (MVD) was determined by immunostaining by using goat-anti-mouse polyclonal antibody CD105. The results showed that on the 21th day following treatment, the volume of xenografts in the TNP-470 plus BCNU group was (108.93±17.63)mm³, markedly lower than that in the TNP-470 group [(576.10±114.29)mm³] and the BCNU group [(473.01±48.04)mm³] (both P<0.01). And the xenograft volume in these 3 treatment groups was even much lower than that in the control group [(1512.61±470.25) mm³] (all P<0.01). There was no significant difference in the volume of xenografts between the TNP-470 group and the BCNU group (P>0.05). The inhibition rate of the tumor growth in the TNP-470 plus BCNU group was (92.80±11.37)%, notably higher than that in the TNP-470 group [(61.91±6.29)%] and the BCNU group [(68.73±9.65)%] (both P<0.01) on the 21th day following treatment. There was no significant difference in the inhibition rate of tumor growth between the TNP-470 group and the BCNU group (P>0.05). The MVD of xenografts in the TNP-470 plus BCNU group was decreased significantly as compared with that in the TNP-470 group or the BCNU group (both P<0.05). The MVD of xenografts in the 3 treatment groups was markedly reduced as compared with that in the control group (all P<0.05). No significant changes in weights were observed before and after the treatment in each group (all P>0.05). It was concluded that the combination of TNP-470 and BCNU can significantly inhibit the growth of human glioblastoma xenografts in nude mice without evident side effects.