Methylene blue is a commonly used dye as well as the first synthetic medicine ever developed, used for for treating malaria and cyanide poisoning. It is also being researched for its potential as a photosensitiser both for microbial disinfection and for killing cancer cells. It exhibits antioxidant, antimalarial, antidepressant and cardioprotective effects.

It is a special dye that generates and increases oxygen levels in tumours. After being injected into the bloodstream, it accumulates in the tumour, where it interacts with the cancer cells. This interaction causes it to reduce to its colourless form in the tumour microenvironment and becomes a powerful catalyst that helps to increase oxygen levels in the tumour. As cancer cells thrive in low-oxygen surroundings, increasing oxygen levels make it harder for them to survive. This rise in oxygen levels makes cancer cells more susceptible to radiation and chemotherapy.

One of the mechanisms through which methylene blue exerts its anti-cancer effects is by targeting the mitochondria of cancer cells. Methylene blue has been found to disrupt the electron transport chain in cancer cell mitochondria, leading to a reduction in ATP production (the primary energy currency of cells) and ultimately causing the cancer cells to undergo apoptosis (cell death).

Moreover, methylene blue has been shown to have a synergistic effect when combined with other cancer treatments such as radiation therapy and chemotherapy. In one study, the combination of methylene blue and radiation therapy was found to be more effective in inhibiting tumour growth in mice with breast cancer than either treatment alone.

Methylene blue has been identified as a potential preventive measure against cancer. Its antioxidant and anti-inflammatory properties play a role in reducing the risk of developing cancer. According to recent studies, methylene blue can help prevent cancer by inhibiting the growth of cancer cells and reducing the number of mutations that lead to cancer.

Additionally, methylene blue may have applications in early cancer detection and intervention. Research suggests that methylene blue can be used to identify cancer cells, making it easier for doctors to diagnose the disease in its early stages. Once detected, methylene blue can be used as part of a comprehensive treatment plan to target and inhibit tumour growth.

Methylene blue is a low-cost drug and when exposed to light with a suitable wavelength, can kill cancer cells directly through the reactive oxygen species generated by the light-excited methylene blue. This treatment is called photodynamic therapy, which can be performed with Methylene blue at very low concentrations.

When methylene blue is used in treatment with photodynamic therapy, it improves its efficacy, which helps against diverse types of cancer, including colorectal tumours, carcinoma, and melanoma. Oncology seems to be a promising area for methylene blue use thanks to its pronounced photosensitising action that results in the disruption of pathological cells under the influence of light. This effect occurs because of the phenothiazine chromophore. It absorbs the light in the range of wavelengths from 630 to 680 nm, which leads to the generation of reactive oxygen species leading to cell death.

This compound was firstly synthesised as a textile dyestuff by Caro in 1876. Later, Ehrlich in cooperation with co-authors described the ability of methylene blue to stain the nervous tissue and to act as an analgesic and antimalarial component. Although the clinical use of this dye was cancelled due to the blue colorisation of urine, it was used in malaria management throughout the 19th century. Nowadays, in the United States and the European Union, methylene blue is applied in methemoglobinemia treatment and for staining of colorectal tumours.

Listen to the Yes to Life Radio Shows Featuring This Therapy:

• Out of the Blue, with Dr Sarah Myhill, Show #446 – Date: 9 Feb 2024

Sources:

• Taldaev A, Terekhov R, Nikitin I, Melnik E, Kuzina V, Klochko M, Reshetov I, Shiryaev A, Loschenov V, Ramenskaya G. Methylene blue in anticancer photodynamic therapy: systematic review of preclinical studies. Front Pharmacol. 2023 Sep 28;14:1264961. doi: 10.3389/fphar.2023.1264961. PMID: 37841915; PMCID: PMC10568458.
• Methylene Blue for Cancer Therapy, Macsen Labs
• Biomaterials for Modern Cancer Imaging and Therapies, pp. 89-109 (2024) Chapter 6: Methylene Blue for Cancer Photodynamic and Photothermal Therapy
• Methylene Blue and Cancer: Exploring the Connection, August 12, 2023, Cancer Center for Healing
• Dos Santos AF, Terra LF, Wailemann RA, Oliveira TC, Gomes VM, Mineiro MF, Meotti FC, Bruni-Cardoso A, Baptista MS, Labriola L. Methylene blue photodynamic therapy induces selective and massive cell death in human breast cancer cells. BMC Cancer. 2017 Mar 15;17(1):194. doi: 10.1186/s12885-017-3179-7. PMID: 28298203; PMCID: PMC5353937.