Nanoparticles hitchhike on whiteblood cells to kill tumour cells in bloodstream.

Prostate cancer is the development of cancer in the prostate, a gland in the male reproductive system.  Most often, prostate cancer spreads to the bones and also to the liver or lungs. It’s rarer for it to spread to other organs, such as the brain.  Once prostate cancer has progressed in its metastatic form, the disease has poor prognosis and limited treatment options.  Now, a study from researchers at Cornell University has identified potent cancer-killing proteins which can travel via white blood cells to kill tumours in the bloodstream of mice with metastatic prostate cancer. The team state that their breakthrough therapy is remarkably effective in vivo and shows several advantages, such as no toxicity and getting good results with very low dosages.

Previous studies show that cancer that spreads outside the prostate gland to the lymph nodes, bones, or other areas is called metastatic prostate cancer.  There are ways to help control its spread and related symptoms, with treatments that slow the spread of advanced prostate cancer and relieve symptoms often causing side effects. Some patients, often those who are older, decide that the risk of side effects outweighs the benefits of treatment and may choose not to treat their advanced, or metastatic, prostate cancer.  Currently, no treatments can cure advanced prostate cancer.  The current study, using mouse models, shows that this therapy seeks, attacks and destroys cancer cells circulating in the bloodstream, and prevents the growth of metastatic tumours.

The current study implanted prostate cancer cells into the prostate of male mice to let the tumours grow. Results show that secondary tumours were prevented by the treatment and that the primary tumour shrunk in size.  Data findings show that while treated mice showed no metastases, the circulating tumour cell count remained greatly reduced but not completely zero.  The team hypothesize that this suggests treatments may not have to be perfect in completely eliminating circulating tumour cells to observe a very good outcome.

The group state that they developed nano-sized liposomes with a protein called TRAIL (Tumor Necrosis Factor Related Apoptosis-Inducing Ligand) that attach to white blood cells.  The lab explain that the liposomes are about one-one hundredth the size of the white blood cells. Results show that as the white blood cells travel throughout the bloodstream, the hitchhiking TRAIL protein kills the tumour cells, leaving the bloodstream free of cancer.

The team surmise that it was their wildest dream to completely prevent the spread of prostate cancer and that’s what happened in their study.  For the future, the researchers state that they have found that a single dose of the therapy, even delivered very late in the course of the disease, can substantially reduce the number of tumour cells.  They go on to conclude that this suggests it may never be too late to help.

Source: Cornell University


Human prostate cancer cells SEM.  Credit: © Dr. Gopal Murti/Visuals Unlimited/Corbis.
Human prostate cancer cells SEM. Credit: © Dr. Gopal Murti/Visuals Unlimited/Corbis.

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