Magnetic tracking of implanted cells boosts cancer treatment outlook: study

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <table border="0" cellpadding="0" cellspacing="0" width="95%" height="1"> <tr> <center> <td valign="top" width="33%" height="33"> <p class="MsoNormal"><b><font face="Arial" size="5">Magnetic tracking of implanted cells boosts cancer treatment outlook: study</font></b></p> <p class="MsoNormal"><font size="1" face="Arial">Nov. 19</font><font face="Arial"><font size="1">, 2005<br> Courtesy Johns Hopkins Medical Institutions<br> and World Science staff<br> </font> <br> </font> <font face="Arial" size="2"><b>Researchers say they have for the first time successfully tracked therapeutic cells implanted into cancer patients, using an imaging technology to detect magnetic probes made of tiny particles.<br> <br> This tracking is important because the cells, injected to help stimulate patients’ own immune systems, have tended to go to the wrong parts of the body in past studies, the researchers said.<br> <br> The new study revealed that “In four of the eight patients… the implanted cells weren’t where they needed to be to be effective for treatment,” said Jeff Bulte, Ph.D., of Johns Hopkins Medical Institutions in Baltimore, Md. <br> <br> Bulte has developed methods to label implanted cells with iron oxide particles that can be tracked using Magnetic Resonance Imaging (MRI), to find out where the cells are.<br> <br> This new application of the particles—already clinically approved for MRI scanning of the liver—could dramatically improve efforts to test and use cellular therapies such as vaccines to treat cancer or prevent its recurrence or stem cells to repair damaged organs, say the researchers. <br> <br> Bulte’s team used a magnetic probe approved by both European and U.S. agencies to locate therapeutic cells injected into eight melanoma (skin cancer) patients. <br> <br> “Our results show that the MRI-based technique was more accurate than tracking the cells using radioactivity and that ultrasound failed to accurately guide injection of the cells into lymph nodes in half of the patients,” said Bulte, an author on the report, which appears in the November issue of the journal Nature Biotechnology.<br> <br> The cells used in the current study, so-called dendritic cells, are the immune system’s own “most wanted posters” because they take up and display foreign molecules that tell the immune system’s fighters what cells to look for and destroy. <br> <br> Since the mid-1990s, clinical trials have been testing dendritic cells to see whether they can stimulate the immune system to kill cancer cells. In these trials, dendritic cells from patients are exposed to proteins from the patients’ cancer cells and then returned to the patients.<br> <br> However, some of the clinical trials of such “cancer vaccines” have been disappointing, with some patients responding very well but others not at all. <br> <br> A critical issue behind each patient’s success is whether the cells get to the lymph nodes, where the immune system’s fighters are normally “trained” by dendritic cells. Until now, there’s been no accurate way to know where the cells end up.<br> <br> It’s thought, but not proven, that the best way to get the cells where they need to be is to inject them directly into the lymph nodes that drain the area containing a tumor. Currently, doctors use ultrasound to guide the needle, and dendritic cells carrying a radioactive tag are sometimes used to try to double-check the cells’ final resting place.<br> <br> However, in this study, the Dutch team discovered that using MRI and iron oxide particles was able to track the cells’ location much more accurately than the radioactive tracking method and provided anatomic detail simultaneously—structural detail not possible by tracking radioactivity.</b></font> </p> <p class="MsoNormal"> <b> <font face="Arial" size="2">* * *</font> </p> <p><font face="Arial" size="2" color="#FFFFFF">Send us a <a href="mailto:editor@world-science.net">comment</a> on this story, or <a href="mailto:?Body=http://www.world-science.net/othernews/051119_probefrm.htm">send it to a friend</a></font> </p> <p> </b> </p> </center> </td> </tr> </table> </body>