Genetically modified virus for early cancer diagnosis
Cancer contracted herpes and turned greenAlla Solodova, Infox.ru
Biotechnologists from the Clinical Center of Cincinnati Children's Hospital (Cincinnati Children's Hospital Medical Center) tracked down single cancer metastases and microscopic tumors using a genetically modified Herpes Simplex virus. An experimental mutant virus (rQ–M38G) finds and infects only actively multiplying (cancer) cells. The tumor cell does not die from infection, but begins to glow. According to the green light of luciferase (Gaussia luciferase – GLuc), medical scientists detect small clusters of cancer cells that have not yet made themselves felt.
Metastases lit upProbably, the proposed method will cause fears and a lot of indignation: how is it possible to infect a person with a virus (and even a mutant!)?
What if it takes root and affects healthy organs? And is it really impossible to determine the beginnings or metastases of oncological rebirth in some other, less risky way?
Indeed, in the arsenal of physicians there are some biomarkers by which oncological degeneration can be diagnosed. But there are still few molecular markers, and in pediatric oncology there are no such "beacons" at all: most tumors do not "report" their origin.
Scientists led by Andrew Brown have created and tested a genetically modified virus that causes a cell to inform doctors that it is sick. The genetic code of mutant herpes is such that the virus does not pay attention to healthy cells, it is attracted only by those that multiply too actively. The rQ-M38G virus is "armed" with the luciferase gene. This gene is the baton that herpes transmits to the diseased cell. As soon as the "baton" passes from the virus to the cell, the latter turns green. Moreover, glowing green cells can be seen in vitro (in urine, blood and tissue samples) and in vivo (in the body itself). That is, the herpes mutant works both as a portable tomograph and as a biomarker.
Scientists note that the described achievements of biotechnology have already been confirmed in experimental practice. In the first experiment, scientists tested the "viral tomograph" in an in vitro experiment – in cell culture. It turned out that the mutant virus almost does not infect healthy cells. But atypical cells of the kidneys, nervous system, muscles and bones turned into "fireflies" – turned green and lit up under the microscope.
In an in vivo experiment, scientists looked for cancer in laboratory rodents. Biologists injected the rQ-M38G virus into the blood and directly into the tumor. In more than 90% of cases, biologists found experimental tumors of even microscopic sizes.
However, for a mouse organism, a three–millimeter neoplasm is already a big bump. Therefore, scientists are not sure that on a human scale they will be able to find green traces of millimeter tumors. But you can track down a centimeter cancer: "In the human body, you can notice a tumor with a diameter of only 8.5 millimeters," write the authors of a new study published in PLoS ONE (Browne et al., Cancer Screening by Systematic Administration of a Gene Delivery Vector Encoding Tumor–Selective Secretable Biomarker Expression). – It is necessary that the virus infects at least 1% of these cancer cells."
"If the method tested on rodents is equally effective and safe in the human body, then the modified herpes virus can be used portably, instead of a tomograph," says Timothy Cripe, co–author of the study.
Scientists plan to continue their research and hope that in the near future general cancer screening will be a common and publicly available procedure.
Portal "Eternal youth" http://vechnayamolodost.ru12.05.2011