Laser-heated carbon nanotubes kill breast cancer stem cells
24 February 2012
Researchers at Wake Forest Baptist Medical Center in the US
have shown that injecting multiwalled carbon nanotubes (MWCNTs) into
tumours and heating them with a 30-second laser treatment can kill them.
Earlier research in 2009 showed it could be done with kidney
tumours, but now they have studied the technique with
tumour-initiating cancer stem cells. These stem cells are hard to
kill because they don’t divide very often and many anti-cancer
strategies are directed at killing the cells that divide frequently.
The Wake Forest Baptist research findings are reported online
ahead of April print publication in the journal Biomaterials.
The research is a result of a collaborative effort between Wake
Forest School of Medicine, the Wake Forest University Center for
Nanotechnology and Molecular Materials, and Rice University.
Lead investigator and professor of biochemistry Dr Suzy V Torti
PhD, of Wake Forest Baptist, said the breast cancer stem cells tend
to be resistant to drugs and radiotherapy, so targeting these
particular cells is of great interest in the scientific community.
“They are tough. These are cells that don’t divide very often,"
she said. "They just sort of sit there, but when they receive some
sort of trigger — and that’s not really well understood — it’s
believed they can migrate to other sites and start a metastasis
somewhere else,” Torti explained. “Heat-based cancer treatments
represent a promising approach for the clinical management of
cancers, including breast cancer.”
Using a mouse model, the researchers injected tumours containing
breast cancer stem cells with carbon nanotubes. By themselves, said
Torti, nanotubes don’t have any anti-tumour properties, but if they
are exposed to laser-generated, near-infrared radiation they start
to vibrate and produce heat. This combination can produce a local
region in the tumour that is very hot, she said. Using this method,
the group was able to stop the growth of tumours that were largely
composed of breast cancer stem cells. This suggests that nanotube-mediated
thermal treatment can eliminate both the differentiated cells that
constitute the bulk of the tumour and the cancer stem cells that
drive tumour growth and recurrence.
“To truly cure a cancer, you have to get rid of the entire
tumour, including the small population of cancer stem cells that
could give rise to metastasis,” Torti said. “There’s more research
to be done. We’re looking at five to 10 years of more study and
development. But what this study shows is that all that effort may
be worth it — it gives us a direction to go for a cure.”