Abstract
We investigated the effect of the hot-water extract of Cordyceps sinensis (HWE) on lung metastasis of B16 melanoma cells in mice. The results indicated that oral administration of HWE inhibited the lung tumor colonies in the models of the experimental metastasis and the spontaneous metastasis, and a 250 mg/kg administration dose of HWE shown the maximum inhibitory effect in mice.Then we examined the inhibitory mechanism of HWE in lung metastasis. As expected, the lung metastasis of B16-F10 melanoma cells was enhanced in C57BL/6 mice pretreated with anti-asialo GM1 serum or 2-chloroadenosine compared to normal mice. This indicates that NK cells and macrophages play important roles in the inhibition of metastasis of tumor cells. Oral administration of HWE led to a significant reduction of the number of metastatic colonies in mice pretreated with 2-chloroadenosine; whereas it did not inhibit lung metastasis in anti-asialo GM1 pretreated mice. It is shown that inhibitory mechanism of HWE in lung metastasis may be related to the activation of NK cells in the host immune system.
