In Dr. Shwartz's lecture, she discussed how delivery was a major problem for cancer treatment. I found a science article claiming that there may be a new way to attack cancer. Cancer drugs are able to penetrate just a few cells into the tumor, but now biologists have discovered a molecule that aids cancer treatments reach deeper into tumors. This has been used only on mice so far and has yet to be tested on humans. Tumors impede drugs in two ways. First, the vessels of tumors are not permeable enough to let drugs inside. Secondly, fluid does not tend to flow towards tumors, it flows away. A new peptide called iRGD can get inside tumors when attached to a cancer drug. 
This small molecule was reported last year by three scientists: Ruoslahti, Kazuki Sugahara, and Tambet Teesalu. They, along with other colleagues, have tested the peptide with different cancer therapies in mice and found that there was a significant increase (7-40 times higher) on how much drug entered into the tumor with the presence of iRGD. With the aid of this molecule, drug-dosage was reduced and only about a third of the drug was now needed to be considered effective. Ruoslahti believes that iRGD can tackle both the tight blood vessels and the high hydrostatic pressure by hooking up to receptors on a tumor's blood vessels, and then binding to another receptor on tumor cells that regulates permeability of their vascular system. Researchers recently reported (http://www.sciencemag.org/content/328/5981/1031.abstract) that the peptide can be simply given at the same time as the drug. Zena Werb, a cell biologist at UC San Francisco, believes that it is too early to evaluate how successful iRGD may be. David Cheresh, a tumor and vascular biologist at UC San Diego, states that there may be a risk in using iRGD because the peptide could potentially open tumor blood vessels, and cancer cells could slip out causing the cancer to metastasize. But most researchers agree that if everything goes well as expected, this molecule could have the potential to change cancer treatment for the better. currently, Ruoslahti and his team have filed patent apllications on iRGD and are now discussing about testing it on humans with other drug companies.
Since this peptide is fairly new, I've decided to do some more research on it. In another article (http://cancerres.aacrjournals.org/content/62/18/5139.full.html), reserachers conducted an experiment using "fluorescence-activated cell sorting (FACS) analysis in combination with an isopentane freezing method to show targeted binding of the Arg-Gly-Asp (RGD)-4C-peptide labeled with FITC, not only to endothelial cells but also to tumor cells in human breast cancer xenografts grown in nude mice." What they concluded was that (RGD)-4C-peptide is capable of targeting coupled molecules to both of these types of cells in human xenografts. Another article (http://www.sciencemag.org/content/279/5349/377.full) found that two peptides coupled to doxorubicin, an anti-cancer drug, reduced its toxicity and increased the efficacy of the drug against human breast cancer in xenografts in nude mice.
So what does this all mean for the future of cancer treatment? If this iRGD molecule, along with an anti-cancer drug, helps get deep into tumor cells, then does this mean that maybe certain cancers can be "eliminated" if found early enough? Perhaps cancer treatment may be cheaper since lower doses can be used. This may sound too good to be true and maybe it is if David Cheresh is correct about his previous statement about a possible downside to iRGD. The only way to really found out is to have human clinical trials.
