Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), in cooperation with colleagues at the University of Zurich and the Ruhr-Universit\u00e4t Bochum, have for the first time successfully tested a new tumour diagnosis method under near-real conditions. The new method first sends out an antibody as a ‘spy’ to detect the diseased cells and then binds to them. This antibody in turn attracts a subsequently administered radioactively labelled probe. The scientists could then clearly visualize the tumour by utilizing a tomographic method. This procedure could improve cancer treatment in the future by using internal radiation.<\/p>\n
The human immune system forms antibodies that protect the body from pathogens. Antibodies can also, however, be produced in a laboratory to precisely bind to tumour cells. They are used in cancer research to detect and fight malignant tumours. For example, antibodies can serve as transport vehicles for radionuclides, with which the affected regions can be visualized or can even be damaged. Until recently, a stumbling block has been their large molecular mass. \u201cThis causes them to circulate in the body for too long before they reach the diseased cells,\u201d explains Dr Holger Stephan from the Institute of Radiopharmaceutical Cancer Research at HZDR. ‘This is a disadvantage because organs that are not affected by the disease are exposed to radiation. It also makes the exact localization of the tumour in the body more difficult because the resulting images are less sharp.\u201d<\/p>\n
Together with colleagues at the University of Zurich and the Ruhr-Universit\u00e4t Bochum, the researchers from Dresden therefore chose an alternative strategy. \u201cBy using what is known as \u2018pre-targeting\u2019, the antibodies\u2019 task is divided into two steps,\u201d Dr Kristof Zarschler, a member of Stephan’s team, explains. \u201cIn a figurative sense, we first send spies out in advance, over a longer period of time, to scout out the enemy \u2013 the tumour cells. The \u2018spies\u2019 then share their position with their troops, which we subsequently send out so that they will directly reach their target with the radioactive material.\u201d The researchers fall back on the cetuximab antibody as the scout, which binds selectively to the epidermal growth factor receptor (EGFR). In various types of tumours, there is an increase in this molecule\u2019s formation or it might be found in a mutated form, which then leads the cells to grow and multiply uncontrolled.<\/p>\n
The Dresden researchers combined the antibody with a peptide nucleic acid (PNA) derivative which Prof Gilles Gasser and Prof Nils Metzler-Nolte developed together with their respective working groups in Switzerland and Germany. \u201cIt is a very stable synthetic variant of DNA,’ says Holger Stephan. \u201cSimilar to a single strand of DNA, it consists of a certain sequence of the four organic bases. Complementary PNA with matching sequence binds to it in a highly precise and stable manner.\u201d During their experiments, the scientists first injected the PNA-EGFR antibody into tumour-bearing mice and gave this \u201cspy\u201d time to accumulate at the tumour site. They then administered the PNA counterpart, labelled with the radioactive substance technetium-99m. \u201cImages we took using single photon emission computed tomography show that both the antibody and its counterpart located each other quickly,\u201d says Zarschler, pleased with the results.<\/p>\n
The tumour could thus be clearly visualized within a short period of time. \u201cFurthermore, the radioactively labelled probes had already disappeared from the bloodstream after sixty minutes,\u201d explains Holger Stephan. \u201cThis minimizes radioactive exposure risk of healthy body tissue. By pre-targeting, we can overcome limitations of conventional, radioactively marked antibodies.\u201d According to the researchers, it will, however, take some time before the combination of PNA antibodies and their matching PNA counterparts can be used in diagnosing tumours in humans.<\/p>\n
\u201cOur results however show that the PNAs we tested are suitable candidates for further preclinical studies,\u201d Stephan sums up. They could provide new possibilities not only for visualizing diseased cells but also for fighting them. \u201cIf the method is proven to work, it could also be used to transport therapeutically effective radioactive substances to the tumour in order to irradiate it from within and ultimately damage it.\u201d\nHelmholtz-Zentrum Dresden-Rossendorf<\/link>\n","protected":false},"excerpt":{"rendered":"
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), in cooperation with colleagues at the University of Zurich and the Ruhr-Universit\u00e4t Bochum, have for the first time successfully tested a new tumour diagnosis method under near-real conditions. The new method first sends out an antibody as a ‘spy’ to detect the diseased cells and then binds to them. […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[35],"tags":[],"_links":{"self":[{"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/posts\/1357"}],"collection":[{"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/comments?post=1357"}],"version-history":[{"count":0,"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/posts\/1357\/revisions"}],"wp:attachment":[{"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/media?parent=1357"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/categories?post=1357"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/clinlabint.com\/wp-json\/wp\/v2\/tags?post=1357"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}