Extracellular pH in many tumors has been shown to be lower, or more acidic, than in surrounding tissues. The present study was done to evaluate the role of pH in metastatic disease. Mice with metastatic melanoma to the lungs were studied. Cancer cells were cultured in acidic culture as compared to more alkaline environments.
Melanoma cells that were cultured at 6.8 pH as compared to controls grown at 7.4 pH showed greater production of proteinases and proangiogenic factors, promoted angiogenesis, blocked apoptosis and increased metastases in the experiments.
Metalloproteinase inhibitors, cysteine proteinase inhibitors, and treatment with blocking antibodies against vascular endothelial growth factor-A or interleukin-8 can inhibit acidity-induced metastases. Acidic pH increases pulmonary metastasis in various human melanoma cells by up-regulation of the proteolytic enzymes, MMP-2, MMP-9, cathepsin B, and cathepsin L and up-regulation of VEGF-A and IL-8.
CONCLUSION: Melanoma cells that were grown in a 6.8 pH for 48 hours showed increased potential to form metastases in mice. The authors conclude that “…treatment strategies involving deliberate tumor acidification should be avoided since acidic pH may enhance the metastatic potential of tumor cells.” This acidification is sometimes used to enhance chemotherapy, photodynamic therapy and hypothermia.
NOTE: Proangiogenic factors promote the new growth of blood vessels, which are necessary for tumors to increase in size. VEGF is a chemical produced by cells, which promotes the production of new blood vessels.
Summary 81 is about an article by McCarty, MF, in Integrative Cancer Therapies in 2006 (PMID: 16282507.) McCarty describes Multifocal Angiostatic Therapy (MAT) as a treatment method that attempts to prevent cancers from growing new blood vessels by blocking VEGF. With a low-fat vegan diet and exercise the following supplements that serve this function are: DIM from cruciferous vegetables, silymarin (Milk thistle extract), zinc, green tea, glycine, selenium.
Read about melanoma, proton pump inhibitors and acidity.