Hyperthermic Treatment with Carbon Nanotubes Kills Breast Cancer Stem Cells

Hyperthermic treatment of breast tumors with multiwall carbon nanotubes (MWCNTs) has been found to kill both differentiated cancer cells and the breast cancer-stem cells that drive tumor growth and recurrence.

Breast tumors contain a small population of tumor initiating stem-like cells, termed breast cancer-stem cells (BCSCs). These cells, which are refractory to chemotherapy and radiotherapy, are thought to persist following treatment and drive tumor recurrence.

Having successfully used MWCNTs to treat breast tumors in a mouse model, investigators at Wake Forest Baptist Medical Center (Winston-Salem, NC, USA) examined their effect on. To this end, they worked with a mouse breast-cancer model. Tumors containing BCSCs were injected with nanotubes, which were then exposed to laser-generated, near-infrared radiation. The nanotubes vibrated, creating local areas of high temperature.

Results published in the April 2012 online edition of the journal Biomaterials revealed that that despite being markedly resistant to traditional hyperthermia BCSCs were sensitive to nanotube-mediated thermal treatment and lost their long-term proliferative capacity. Moreover, use of this therapy in vivo promoted complete tumor regression and long-term survival of mice bearing cancer stem cell-driven breast tumors.

The investigators speculated that nanotube thermal therapy promoted rapid membrane permeabilization and necrosis of the BCSCs. Destruction of the BCSCs prevented recurrence of the tumor.

“They are tough. These are cells that do not divide very often. They just sort of sit there, but when they receive some sort of trigger – and that is not really well understood – it is believed they can migrate to other sites and start a metastasis somewhere else,” said senior author Dr. Suzy Torti, professor of biochemistry at Wake Forest Baptist Medical Center. “Heat-based cancer treatments represent a promising approach for the clinical management of cancers, including breast cancer.”

“To truly cure a cancer, you have to get rid of the entire tumor, including the small population of cancer stem cells that could give rise to metastasis,” said Dr. Torti. “There is more research to be done. We are 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.”

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Wake Forest Baptist Medical Center