The power of light
Pleural mesothelioma is a rare type of cancer formed from the mucous membrane of the lungs. It does not spread to other parts of the body for a long time, but it is usually diagnosed too late when metastases grow into the lungs, intercostal muscles, ribs. This worsens the prognosis and limits treatment options.
An oncologist from Nagoya University Kazuhide Sato and his colleagues investigated the effectiveness of near-infrared photoimmunotherapy (NIR-PIT) as a strategy for the treatment of pleural mesothelioma. This method is currently approved for the treatment of malignant tumors of the head and neck.
For NIR-PIT to work, an anti-cancer compound must first be introduced. It consists of two components. The NZ-1 antibody targets a specific part of the transmembrane glycoprotein podoplanin, which is usually present on many types of human cells, but is especially common in cancer cells, including pleural mesothelioma. The second component of the anticancer compound is the photoabsorber IR700. Antibody-IR700 conjugate is non-toxic to the body in the absence of near-infrared light radiation. NIR-PIT is a safe phototherapy option that can be targeted at an area of interest.
The lungs and chest cavity contain a large amount of air and therefore transmit near infrared light very well. When it hits the cancer-affected area, the compound NZ-1-IR700 accumulates on the membranes of cancer cells and leads to their rupture and tumor death.
The group's studies have shown that podoplanin is actively expressed in various cell lines of pleural mesothelioma. They demonstrated that NZ-1 conjugates well with the IR700 photoabsorber and that NZ-1-IR700 specifically binds to podoplanin on cells in vitro. When NZ-1-IR700 was added to the cells containing podoplanin, including pleural mesothelioma cells, and then they were irradiated with near-infrared light, the cells quickly swelled and ruptured.
The researchers then injected NZ-1-IR700 into mice with pleural mesothelioma. The compound gradually accumulated in the tumor. Exposure to near-infrared light on the cancer zone led to a decrease in fluorescence from labeled cancer cells, proving that the treatment was effective as an anti-cancer strategy.
Sato and his colleagues now intend to change the strategy so as to make it safe for healthy sub-planin-containing cells. The researchers also suggest that a more focused exposure to light can be achieved by placing it in a drainage device, which is commonly used in most patients with pleural mesothelioma to remove excess fluid from the chest cavity.
Article by Y.Nishinaga et al. Targeted Phototherapy for Malignant Pleural Mesothelioma: Near-Infrared Photoimmunotherapy Targeting Podoplanin is published in the journal Cells.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on materials from Nagoya University: Shining light on a malignant lung cancer.