Scientists from Okayama University, Japan, have discovered a way to destroy cancer cells by increasing their alkalinity with the help of light, writes Yurikalert, referring to a publication in the Journal of the American Chemical Society.
One of the hallmarks of cancer cells is their ability to avoid apoptosis, or programmed cell death.
The authors of the study explain that an excessively alkaline environment disrupts the work of mitochondria - the energy stations of cells, which triggers apoptosis. Normally, tumor cells avoid this type of programmed death by changing the expression of proteins.
For this reason, methods that restore the sensitivity of cancer cells to apoptosis are considered a more gentle alternative to classic chemotherapy. One of these options is optogenetics - activating light-sensitive molecules with a laser.
The focus of this study is the microbial protein archaeorhodopsin-3 (AR3). Under the influence of green light, it "pumps" hydrogen ions out of the cell, increasing its pH and leading to disruptions in the functioning of mitochondria.
The team introduced the AR3 gene into the cells of two types of tumors in mice - colorectal cancer and melanoma. When illuminated with green light, apoptosis was massively triggered in the cells with AR3, killing over 40 percent of those with colorectal cancer and over 60 percent of those with melanoma. In the absence of light, a similar effect was not observed.
The researchers then transplanted the modified cells into mice. When a green laser was directed at the formed tumors, their growth slowed significantly. After 13 days, the size of tumors with AR3 was 65-75 percent smaller than those without the protein. In the case of colorectal cancer cells, activation of immune responses against the tumor was also observed.
The scientists note that in the experiments, the AR3 protein was introduced in advance, before the tumors formed. Further studies are needed to determine whether existing tumors can be made to express the protein and become sensitive to light therapy.