Novel smart drug delivery techniques may lead to less harmful cancer cure
Developing a cure for cancer is one of the most difficult and most necessary initiatives in modern medicine. As of now, there are numerous treatments for various forms of cancers, and probably twice that amount of experimental trials attempting to defeat one of humanity’s most dangerous diseases. One of the latest developments in cancer treatment is smart drug delivery, or targeting specific cells with specific doses rather than flooding a person’s whole body. Ideally, these treatments will be able to discriminate between cancer and patient, eliminating the disease and leaving the patient far healthier than current treatments.
Currently, chemotherapy and radiation therapy are the two most widespread cancer treatment options, apart from surgery. Chemotherapy treatments introduce chemicals toxic to cells into the blood stream, allowing the chemicals to potentially treat cancer throughout the body. These chemicals affect cell division in a number of ways. There are cell-cycle-specific chemicals, which target cells in the process of dividing, and cell-cycle non-specific chemicals, which target cells at other times. Since the most notable property of cancer cells is that they divide rapidly, this seems like a fairly straight-forward treatment. However, this approach affects not only cancerous cells, but cells which divide rapidly such as hair; epithelial tissue, which lines the digestive tract; and bone marrow, which produces blood cells. Since these cells are affected, this leads to the most notable side-effects of chemotherapy treatments: hair loss, nausea, immunodeficiency, and a host of internal issues.
Like chemotherapy, radiation treatments target cells undergoing the division process. Radiation treatments use objects with high-energy emissions, such as gamma radiation, x-rays, or charged particles, to target cells in certain cancerous areas. This disrupts cell division by breaking holes in the DNA of cancerous cells. These treatments are more targeted than chemotherapy, but they cannot specifically target cancer cells while leaving surrounding healthy tissue unaffected.
Another major issue, at least with chemical treatments, is that some cancers become resistant to the drugs used to fight them. This road block has led researchers down a path to discover smarter ways to target these drug-resistant cancer cells and how best to eliminate them. This method, called targeted drug delivery, involves targeting specific cancerous cell types with deadly chemicals while leaving surrounding tissue unaffected. One of the most interesting questions this concept has posed is what to package these cancer-defeating drugs in. There are many questions that must be answered before the perfect capsule can be found. What kind of casing can be sturdy enough to transport the drug through the body without spilling it into the body?
How can we ensure that the capsule will be accepted into the cancer cells and deliver the drug effectively?
The Tartan recently covered similar research coming out of Carnegie Mellon in November of 2015. This research focused on creating a liposomal package out of phospholipids, the same material that makes up a cell membrane, to deliver the anti-cancer drugs. This research was theoretical and modeled the concept of creating this capsule.
Researchers at The Ohio State University are using DNA origami structures to perform similar tasks. This research was conducted by John Byrd of The Ohio State University Wexner Medical Center, in collaboration with a number of colleagues. This particular study focused on a type of leukemia that had grown resistant to a certain anti-cancer drug by adapting itself to recognize the deadly chemical and actively pump it out before it can affect the cell. The researchers noted very clearly, however, that the DNA capsule does nothing more than hold and camouflage the drug. One of the most interesting facets of this transport capsule, however, is that researchers “can vary the shape or mechanical stiffness of a structure very precisely and see how that affects entry into cells,” according to Carlos Castro, director of the Laboratory for Nanoengineering and Biodesign, who collaborated with Byrd on this project. The particular anti-cancer drug the researchers used for this experiment is called daunorubicin, a compound that inhibits cell growth by nudging itself into the DNA and sticking there, preventing proper cell division. This drug worked well in the DNA capsules because it naturally adhered to the capsule. This research showcases the usefulness of capsule technology in drug delivery, and has proven effective in both isolated leukemia cells and solid tumors alike. The next step is translating these culture effects into animal models, so that the research can be applied. While chemical treatments are being heavily pursued, the art of researching smart ways to target and destroy cancerous tissue has multiple lines of inquiry within many laboratories across the world. Researchers at Sheffield University in the United Kingdom have been experimenting using viruses, rather than drugs, as the principal method of cancer elimination.
One of the best facets of this approach is that the viruses are self-replicating, so they can target tumors and keep up with the cells’ intense growth cycles. They can also piggyback on the body’s natural immune response to chemotherapy.
The procedure works by implanting macrophages, a type of white blood cell, with viruses and allowing them to naturally seek out tumor sites. In response to chemotherapy, the patient’s blood concentration of macrophages increases, and they rush to the affected tumor sites, responding to the chemical injuries sustained and attempting to heal the damage done. This treatment had prior success in animal models, and it will be experimentally tried on 15 Sheffield men with prostate cancer, the type of cancer with which this treatment has been tested.
Overall, experimental cancer treatments have come a long way in the recent past. Cancer research requires a good amount of innovation, considering the savagery of the disease and its adaptive nature.
Only time will tell how cancer will be conquered, but in this era of heavy experimentation, it’s interesting to consider the routes by which this victory might be won.