Pierisin-1 is a 98kDa protein known to induce apoptosis in various human carcinoma cell lines with a very wide range of IC
50 values. Among those, the cervical carcinoma HeLa cells are the most sensitive, showing IC
50 value of 0.043ng/ml. In the present study, we found that the LD
50 value for pierisin-1 was around 5μg/kg body weight on intraperitoneal injection into female BALB/c mice. To examine whether this novel protein has anti-cancer activity against HeLa cells
in vivo, cells were inoculated intraperitoneally into 6-week-old BALB/c
nu/nu female nude mice on the first day and an intraperitoneal injection of pierisin-1 at a dose of 3μg/kg was given 24h after tumor cell inoculation. Thereafter, animals were sacrificed at day 80 and tumor weight was measured. Tumors were formed in all ten mice inoculated with HeLa cells and the mean tumor weight was 1.16g±0.18g per mouse. In mice inoculated with HeLa cells and treated with pierisin-1, the mean tumor weight was 0.56g±0.21g per mouse, and its value was significantly lower and no tumors were found in three of ten mice tested. Our results indicate that pierisin-1 has anti-cancer activity
in vivo.
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