Method Devised to Reliably Capture Circulating Cancer Cells

Sofia Merajver (University of Michigan)

Engineering and medical researchers at University of Michigan in Ann Arbor with colleagues in China developed a simple technique to capture circulating cancer cells believed to spread cancer from the original tumor to other parts of the body. The team from the labs of Michigan breast cancer researcher Sofia Merajver (pictured left) and biomedical engineering professor Jianping Fu, City University of Hong Kong, and Shanghai Institute of Microsystem and Information Technology published its findings online in the journal ACS Nano; paid subscription required.

Circulating tumor cells are considered key contributors to cancer metastasis, the process that spreads cancer from the original tumor to tissues in other parts of the body. Physicians use blood tests keep count these cells to determine how long a patient with widespread cancer will live. Because circulating cancer cells are relatively few in number — usually one per billion blood cells — they are difficult to locate and identify.

Current methods for tracking circulating tumor cells use beads coated with antibodies to find and bind to surface proteins on the circulating cells. Not all of these circulating tumor cells, however, have these surface proteins, including the more aggressive cancer stem and progenitor cells.

The Michigan team and colleagues developed a simple, mechanical method of capturing circulating cancer cells that takes advantage of the cells’ propensity to settle and bind compared with normal blood cells. Their process uses glass slides with their surfaces etched to a nanoscale roughness. To rough-up the slides to a nanoscale resolution, the researchers adapted a standard and inexpensive microfabrication technique for semiconductors called reactive ion etching.

The tests of the method showed the circulating tumor cells adhere to the nanoscale-roughed surface, independent of the cells’ size or presence of surface proteins. The researchers added circulating tumor cells taken from human breast, cervical, and prostate tissues to blood samples, then poured the cell-laden blood over the roughened glass slides. The tests showed the roughened surfaces capture from 88 percent to 95 percent of the cancer cells.

The senior authors believe this technique can lead to advances in understanding how cancer spreads. “Our system could provide an efficient and powerful way,” says Fu, “to capture the live circulating tumor cells and use them as a surrogate to study the metastatic process.”

The goal, notes Merajver, is to integrate this technology into a better ways of controlling metastases. “The application of integrative biology is necessary to put together the story of how these cells behave in time,” says Merajver, “to achieve successful metastases and thereby discover the routes to suppressing this deadly development.”

The university says it is pursuing a patent for the intellectual property and seeking commercialization partners to help bring the technology to market.

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• Trial Highlights Metastatic Breast Cancer Drug Effectiveness

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