Graphene shows anticancer potential

Date: Feb-26-2015Scientists have discovered that the nanomaterial graphene can target and

neutralize cancer stem cells and is not toxic to healthy cells, suggesting it may

have potential to treat a range of cancers with fewer side-effects than many current

treatments.

Graphene disrupts signals on cancer stem cell membrane.
Image credit: K. Novoselov/University of Manchester

Cancer stem cells are precursor cells that can self-renew and differentiate into

cancer cells and form tumors. Conventional treatments like chemotherapy and

radiotherapy that wipe out the bulk of cancer cells don't always kill cancer stem

cells - a residue can survive and grow.

Residual cancer stem cells drive tumor recurrence and metastasis - where cancer

spreads to other parts of the body. Metastasis is responsible for 90% of cancer

deaths, so any treatment that prevents it will make a huge difference to patient

survival.

Cancer stem cells are also thought to drive drug resistance, causing a

significant problem for the effective treatment of cancer.

Now, a new study suggests that graphene - a nanomaterial made of

extremely thin flakes of carbon that are only one atom thick - may prove to be

effective in eliminating cancer stem cells.

Reporting in the journal  Oncotarget, a team from the University of

Manchester in the UK led by Michael Lisanti, a professor in Manchester's Institute

of Cancer Sciences - describes how graphene oxide - a modified version of graphene -

selectively targeted cancer stem cells in a range of cancers.

The researchers suggest their findings open the possibility of using graphene

with existing treatments not only to shrink tumors but also to prevent recurrence

and metastasis.

Graphene oxide flakes prevented cancer stem cells forming tumor-spheres

The team became interested in graphene - in the form of graphene oxide - because

it has shown potential as a carrier for drug delivery. The material is stable in

water, and readily attaches itself to cell surfaces.

But co-author Dr. Aravind Vijayaraghavan, of Manchester's School of Materials and

National Graphene Institute, says they were surprised to find that it is the

graphene oxide itself that appears to be an effective anticancer drug. He

explains:

"Cancer stem cells differentiate to form a small mass of cells known as a

tumor-sphere. We saw that the graphene oxide flakes prevented CSCs [cancer stem

cells] from forming these, and instead forced them to differentiate into noncancer

stem cells."

However, while he and his colleagues hope these early results will lead to new

cancer treatments, they also caution that there is a lot of work to do before

graphene is ready for clinical trials with cancer patients.

Graphene was effective against six different cancer types

For the study, the team tested a range of graphene oxide formulations of

different flake sizes on cancer stem cells from six types of cancer: breast,

pancreatic, lung, brain, ovarian and prostate.

They used a method that is commonly used to test cancer stem cells, called the

tumor-sphere assay or test. In the test, a tumor-sphere - a solid spherical, fused

mass of cells - develops from a single cancer stem cell. Tumor spheres arising from

cancer stem cells are easy to differentiate from clumps of other types of cell.

The researchers found the graphene oxide flakes prevented cancer stem cells from

forming tumor-spheres across all six types of cancer, suggesting the method could

work for a large range of cancers.

Further investigation revealed that graphene oxide prevents cancer stem cells

from forming tumor-spheres by inhibiting several important signal pathways on the

cells' surfaces.

The team suggests the results show graphene has potential use in

combination therapy, helping to boost results of conventional treatments. Co-author

Dr. Federica Sotgia, also of Manchester's Institute of Cancer Sciences,

concludes:

"These findings show that graphene oxide could possibly be applied as

a lavage or rinse during surgery to clear CSCs or as a drug targeted at

CSCs."

The study builds on the pioneering work of two Manchester University physicists - Andre Geim and Kostya Novoselov - who won the Nobel Prize in Physics after successfully isolating graphene from graphite in 2004.

Meanwhile, Medical News Today recently learned of another study where a

team showed that camel antibodies can ferry anticancer viruses directly to tumor cells. The findings raise the hope of

developing effective gene therapies that target specific cell types.

Written by Catharine Paddock PhD

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.