Can We Stop Cancer From Metastasizing?

Ana Sandoiu wrote an article that explored the subject of a new way to possibly stop cancer from metastasizing.  This is the main cause of death in cancer, and the current treatments against it are so far ineffective.  However, there is current research that may have found a way to slow it down, and maybe to even halt the spread of cancer cells.

This is the process by which the cancer spreads throughout the body.  Cancer cells may either invade the nearby healthy tissue, penetrate the walls of lymph nodes or enter the surrounding blood vessels.  They may now be able to control metastasis by inhibiting the migration of cancer cells.  This is the key in stopping metastasis.

A set of protrusions that help cells to move is what enables the cancer cells to migrate.  Mostafa El-Sayed, Julius Brown Chair and Regents Professor of Chemistry and Biochemistry at Georgia Tech’s School in Atlanta, GA. and his team of researchers, managed to cut off these protrusions using a special technique.

The long, thin protrusions helping the cancer cells to move are called filopodia, and are an extension of a set of broad, sheet-like fibers called lamellipodia.  These can be found around the edges of the cell.  Podia comes from the Greek language and means “something footlike.”  Filopodia and lamellipodia are tiny “legs” that help the healthy cells to move within the tissue.  They are both produced in excess in cancerous cells.

Researchers had used nanorods, made of gold nanoparticles, to obstruct these tiny legs.  Using nanotechnology, the scientists were able to reduce the size of certain materials to a nanoscale, at which point these materials start to show new chemical and physical properties.  “nano” means the billionth part of a meter.

The nano rods were locally introduced by Prof. El-Sayed and his colleagues.  They were covered with a coating of molecules called RGD peptides, that made them attach to a specific kind of protein called integrin.  The nanorods tied up the integrin and blocked its functions so that it could not keep guiding the cytoskeleton to overproduce lamellipodia and filopodia, according to co-author Yan Tang, a postdoctoral assistant in computational biology.  A cytoskeleton is the support structure of a cell, responsible for giving it a shape and has additional function, with one being to form the filopodia protrusions.

They believe the experiments revealed that simply binding the nanorods to the integrin  delayed the migration of the cancer cells.  This method also avoided the healthy cells, which could make this therapy drastically less damaging for patients who undergo toxic chemotherapy treatment.  The second stage of the experiment was heating the gold nanoparticles with a laser of near-infrared light which effectively stopped the migration of the malignant cells.  Light was not absorbed by the cells, but the gold nanorods absorbed it, heated up and partially melted cancer cells they are connected with.  The lamellipodia and filopodia were mangled.

Not all cancer cells were killed in the experiment, as it would have prevented researchers from examining whether or not they successfully stopped them from migrating.  It could, however, be adjusted to kill the malignant cells.  Several experiments have been performed in mice using the same method and found no toxicity from the gold for up to 15 months following treatment.

Their hope is to soon be able to treat the head, neck, breast and skin cancers with direct, local nanorod injections combined with the low-power near-infrared laser.  The laser could reach the gold nanorods at 4 to 5 centimeters deep inside the tissue, and those deeper tumors with deeper nanorod injections.

Dr Fredda Branyon