Inhalation therapy with M1 inhibits experimental melanoma development and metastases in mice.

Background: M1 is a homeopathic medicine with immunostimulatory properties used mainly by cancer patients to complement current therapies. Metastatic melanoma is a skin-originated form of cancer without a single therapy able to produce high rate and sustained responses, which attracts the use of complementary therapies such as M1. However, M1's anti-melanoma effects remain to be pre-clinically demonstrated. Therefore in the present work, we utilized a pulmonary metastatic melanoma model and a subcutaneous melanoma growth model to investigate the potential benefits of treatment with M1.

Methods: C57BL/6 mice were injected intravenously or subcutaneously with B16F10 mouse melanoma cells. After 24 h, mice were treated with either M1 or vehicle (water) for 14 days, euthanized and harvested for multi-parameter pulmonary and tumor analyses.

Results: Mice treated with M1 had significantly lower tumor burden in the lungs and subcutaneous tissue than control mice. Furthermore, tumors were impaired in proliferation and tumor related angiogenesis by the inhibition of myeloid derived suppressor cells (MDSC) positive for angiotensin II type 1 receptor (AT1R).

Conclusion: Altogether these data suggest M1 is an efficient candidate for melanoma therapy to be considered for future clinic studies as this study is the first supporting the idea that melanoma patients may benefit with the treatment. The treatment with M1 provides advantages considering the highly-diluted properties and a cost effective alternative to costly chemotherapeutic approaches with, if any, lower toxicity.