Melanopsin (OPN4) is a light-emitting protein found in skin and retinal cells. A new study conducted at the University of São Paulo (USP) in Brazil shows that OPN4 can also be involved in the development of melanoma, the most serious type of skin cancer.
In experiments with animals and genetically modified cells in the Comparative Physiology of the Pigmentation Laboratory of the Institute of Biosciences (IB-USP), the researchers showed that the disease progresses slowly when this protein is not he worked. The results are reported in an article published in Communication Biology.
Although other groups have already shown that opsins are involved in cancer, this is the first such study melanoma which accounts for 5% of malignant skin tumors and 80% of all cancer deaths.
The basis of the study is research by the same group using samples of melanocytes (the producer of melanin skin cells) to show that melanopsin is expressed in these cells and participates in processes such as pigmentation, biological clock regulation, even cell death due to ultraviolet A light.
The latest study used a DNA editing technique known as CRISPR to change the sequence of the Opn4 gene and create a stable melanoma cell line with an inactive version of the protein.
“When we created the knock-out cells [without a functional OPN4 gene], we realize that they are of the same type. in type ‘in type of type of type of type of type of type of type of type of type of type of type phenotype) they grew: they grew larger and showed reduced reproductive capacity. We wondered why and decided to find out whether melanopsin plays a role in the development of melanoma or carcinogenesis,” said Leonardo Vinícius Monteiro de Assis, first author of the article and currently a researcher at the University of Lübeck in Germany .Assis collaborated on the study with José Thalles Lacerda, the second author of the article.
The principle was confirmed first in experiments done in vitro and then in animals. Tumor cells containing an inactive form of OPN4 proliferated less rapidly than wild-type cells (without correcting OPN4). The discovery was later confirmed using security features and information from public databases.
“In short, we show that cell growth slows down in melanoma when OPN4 is removed. This is due to two unrelated but possible processes: increased activation of the immune system, although we don’t know why; and the reduction of signaling by GTPases, proteins that are like small machines that play a role in the progression of the cell cycle and are significantly reduced in these tumors, “in said Assis.
The study also revealed that MITF (microphthalmia-associated transcription factor), an important transcription factor in melanoma, is not expressed significantly in cells with an inactive form of melanopsin.
According to Assis, all these studies together show for the first time that melanopsin acts as an oncogene in melanoma, i.e., it is related to the growth and development of this type of cancer. Until now, melanopsin has never been linked to the growth of tumors. Further experiments on melanoma cell lines and other methods are needed to reach definitive confirmation of this role.
Miracles
The Comparative Physiology of Pigmentation Laboratory, led by the physicist Ana Maria de Lauro Castrucci, is one of the few research groups worldwide that has shown (in 2018) that melanopsin also detects temperature, acting independently as thermosensor and photoreceptor. With the new information, he has now added another important factor by showing that genetics can be an interesting therapeutic tool in the future.
“Melanopsin can be investigated for the treatment of melanoma, and this opens up a new avenue of research into its role in other diseases, such as liver disease, where opsins are also present,” Assis said.
Casrucci’s lab is currently investigating the mechanism of melanopsin in organs that are not known to be affected, such as adipose tissue, liver, and heart, among others.
Protein that detects light may play a role in the origin and progression of melanoma, study suggests Source link Protein that detects light may play a role in the origin and progression of melanoma, study suggests