5-氨基乙酰丙酸甲酯介导的光动力疗法对局部皮肤黑色素瘤及其转移性肿瘤的抗肿瘤作用及其与抗肿瘤免疫的关系

A non-pigmented melanoma mouse model, which was challenged with human primary melanoma cells WM266-4, was established in 36 nude mice. When the melanoma grew to size of (0.4 ȕ 0.4) cm2, the 36 mice were randomly divided into 4 groups, i.e., ALA-Me intravenous (i.v.) injection-PDT, ALA-Me intraperitoneal (i.p.) injection-PDT, ALA-Me topical application-PDT and control group without any treatment. The dose for systemic administration (i.v. and i.p.) of ALA-Me was 250 mg/kg. For topical application of ALA-Me, a cream with 25 mg/cm2 was smeared on the tumor tissue. The tumor site was irradiated by the red light from LEDs lamp with fluence rate 90 mW/cm2 and energy rate 50 J/cm2.

The inhibitory effects on both tumor growth and metastasis were observed after all three treatments mentioned above. In terms of inhibiting tumor growth, there was a significant difference in the volume of tumor between the treatment groups and the control group (P < 0.05). Furthermore, a very significant (P < 0.01) inhibitory effect on tumor lung metastasis was found after the three treatments. Moreover, the ALA-Me-PDT-induced immune response was also observed by means of increase of immune cells NK cells in the spleen of the T cell-deficient nude mice.

ALA-Me-PDT had significant inhibitory effects both on local tumor growth and distant lung metastasis of melanoma. There was also significant antitumor immunity caused by ALA-Me-PDT. Results of the present study provide a potential possibility for ALA-Me-PDT in the treatment of skin melanoma and its metastasis.