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University of Calgary researchers use new approach to destroy tumours
CALGARY, AB --(Marketwired - February 19, 2016) - Nanoparticles promise to significantly improve the diagnosis and treatment of cancer. Scientists have been designing the tiny, engineered particles (1/10,000 the width of a human hair) to carry drugs into cancer cells to destroy tumours.
However, studies show that typically less than five per cent of a nanoparticles dose delivered through the bloodstream reaches the tumour itself -- greatly reducing treatment effectiveness.
Now, in a novel approach that investigated the 'jello' or extracellular matrix around tumour cells, a team of University of Calgary and University of Toronto researchers has discovered why.
They found that tumour cells' extracellular matrix -- mostly collagen enveloping the tumour -- like jello around a bunch of a marbles -- along with the size of the tumour, significantly affect whether nanoparticles reach their target.
Their interdisciplinary study, a seven-year-long collaboration, was published this week in the Proceedings of the National Academy of Sciences of the United States of America, a globally top-ranked science journal.
"Trying to design the perfect nanoparticle hasn't worked out as well as it should," says David Cramb, professor and department head in the Department of Chemistry in the Faculty of Science and one of several co-authors of the study. "Our study, which focused on tumour physiology and understanding the tumour itself, showed there's this big barrier between the bloodstream and getting to the cells themselves -- which hasn't been looked at before."
Paradigm shift to "personalized nanomedicine"
The research presents a paradigm shift in nanomedicine away from trying to engineer a perfect, 'universal' nanoparticle design for cancer detection and treatment, and could lead to using specific types and sizes nanoparticles to characterize tumours and customize treatments.
The team successfully tested this concept by using selectively-sized nanoparticles to detect prostate tumours in mice, which improved targeting the tumour by more than 50 per cent.
"A tumour is not a tumour -- they're not all the same," says study co-author Kristina Rinker, associate professor and director of the Centre for Bioengineering Research and Education in the Schulich School of Engineering
"The cells are one part of it, but it also has this mass, this extracellular matrix that can be quite variable. And the properties of that matrix are going to affect the treatment effectiveness."
Graduate student built experimental system
The study found that the collagen enveloping breast tumour cells varies greatly in density, both at different locations in the collagen matrix and as a function of tumour volume. This affected the nanoparticles' ability to penetrate the collagen and reach the tumour cells.
Christopher Sarsons, a PhD student in Rinker's bioengineering group and a co-author of the study, built a system that included engineered spherical gold nanoparticles, a fluid outer chamber (representing the bloodstream) and an inner chamber filled with collagen hydrogel (representing the tumour matrix). He then tracked and measured how various-sized nanoparticles moved into the gel.
The research team found that getting nanoparticles to reach the tumour cells involves complex interactions; it is not just a matter of making the particles as small as possible. In some cases, depending on the tumour's collagen density, bigger particles reached the tumor cells more effectively than smaller particles.
The research was funded by the Collaborative Health Research Projects, a joint venture between the Natural Sciences and Engineering Research Council and the Canadian Institutes of Health Research, with support from Alberta Innovates-Technology Futures and equipment funded through Canada Foundation for Innovation and Alberta Advanced Education.
WHEN: February 19, 10 a.m. - 11 a.m.
WHERE: CCIT 125A, parking available in Lot 13 adjacent to building
WHO: Co-authors David Cramb, Kristina Rinker and Christopher Sarsons
ABOUT THE UNIVERSITY OF CALGARY
The University of Calgary is making tremendous progress on its journey to become one of Canada's top five research universities, where research and innovative teaching go hand in hand, and where we fully engage the communities we both serve and lead. This strategy is called Eyes High, inspired by the university's Gaelic motto, which translates as 'I will lift up my eyes.'
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Schulich School of Engineering
University of Calgary