Bioengineers at Duke University have developed a simple and importantly inexpensive method for loading nano-scale delivery vehicles with cancer drug payloads. This nanoformulation was shown to eliminate tumours after a single treatment. In a great step forward for limiting toxicity the nano-scale delivery vehicle breaks down into harmless byproducts after delivery of the drug.
These nano-delivery systems have become very attractive to researchers because of their ability to infiltrate efficiently into tumour cells. The nano-formulations make use of the leaky more porous blood vessels that supply tumours to accumulate easilyin the tumour cells. This means a higher concentration of drug is delivered efficiently to the tumour cells with a lower dosage administered. This reduces the side-effects associated with systemic chemotherapy administration.
Results showed that the nano-formulation increased the maximum tolerated dose of the drug four-fold compared to the drug by itself. This meant that after one injection it created almost complete tumour regression, whereas the drug by itself would usually have only a modest effect in shrinking the tumours.
Just as importantly the research team have produced a delivery system that is inexpensive and could be used with other drugs, which could be used to increase the effectiveness of other drugs.
The delivery system uses E. coli bacteria which have been genetically engineered to produce an artificial peptide known as chimeric polypeptide. E. coli having been used so often to produce proteins is a very efficient producer of these proteins giving a high yield.
When the drug associates with the chimeric polypeptide it can take on characteristics it doesn’t usually posses. Most drugs do not dissolve in water, which limits their ability to be taken up by cells. Attachment to the chimeric polypeptide allows it to become soluble in water.
The latest experiments using this delivery system involved the use of doxorubicin commonly used in the treatment of blood cancers, breast, ovarian and other cancers.
The team at Duke are now looking at testing the formulation on different cancers in different organs. – CT