Triple-play on Cancer
I remember when I was young I didn’t quite understand the concept of cancer. The thought that there was something out there that couldn’t be destroyed through medication, and that didn’t limit its attacks to the frail and elderly but could bring the young and healthy to their knees was frightening. I remember vividly when, in my community theater production of the Neil Simon play, “Brighton Beach Memoirs,” the actor playing Eugene describes with a whisper how his uncle Dave had died of cancer, and that the “c” word was among those better left unspoken among family. It’s a sentiment I carried with me when many members of my family developed stomach cancer, and compounded when I lost some of them to the disease. Its many forms vary in intensity and duration, but all of them are savage to the body they consume.
I was therefore encouraged this week to read about 3 new approaches being taken by scientists in an attempt to attack this disease at its foundation and provide better survival rates to those who are afflicted with it. Each approach is slightly different from the other, and some of the more complex chemistry behind it is lost on me, but their novel approach and heartening results demonstrate the effort that is taking place in order to quell cancer’s devastating effect.
The first two of these therapies I found today on the American Association for Cancer Research page. They both are currently involved in Phase I/Phase II human trials, and were presented on October 24th at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapies.
GlaxoSmithKline funded the study of the new experimental drug, GSK923295A, considered first in its class because of its approach to cancer cells. The drug targets and inhibits a single protein, CENP-E, that functions only during cell division, or mitosis. Without signals from this protein, the mitosis cannot be completed, and the cell dies as a result. This particular protein is a prevalent catalyst in most cancerous cells, and research has demonstrated thus far that damage to healthy cells is limited. This is contrary to most current chemotherapy, which broadly effects all cells in order to destroy the cancer cells.
It has a mesurable effect across a broad range of cancer types, and animal studies have shown complete tumor regression in some cancer types. David Sutton, B.Sc., associate director of biology within the Oncology division of GlaxoSmithKline had the following results to report thus far:
In preclinical tests conducted in 214 solid and 85 hematological tumor cell lines, sensitivity to GSK923295A was seen in 16 out of 17 breast tumor cell lines, 20 out of 25 colon cancer lines, 24 out of 26 lung cancer lines, 11 out of 11 ovarian cancer lines, and six out of six prostate cancer lines, he says. Additionally, laboratory analysis suggests that anti-tumor activity might be achieved with minimal suppression of the bone marrow, which could reduce the typical myelosuppression (reduction in production of blood cells) seen with chemotherapy treatment… (1)
The second anti-cancer drug, being developed by Thallion Pharmaceuticals in association with the Segal Cancer Centre of McGill University, takes a different approach to the disease. ECO-4601 primarily inhibits one of the cell’s communication pathways that is typically mutated by several cancer types (the the RAS/MAPK intracellular pathway, if you must know). This is not an uncommon approach and is in fact the target of several other anti-cancer drugs such as Erbitux, Avastin, Tarceva, Nexavar and Sutent. ECO-4601 distinguishes itself from the others by working at a unique point within the pathway, specifically at the level of the RAS protein itself.
This special protein target is important because RAS acts more as a communications hub rather than a simple line, and blocking its ability to relay messages is more likely to have an effect over a broader ranger of cancers. Other aforementioned drugs that act as inhibitors often face the issue of redundancy in the cell regions on which they work that can keep the communication pathway open, even if it is compromised.
ECO-4601 binds to the peripheral benzodiazepine receptor (PBR), an over-expressed receptor in cancerous cells, leaving less possibility that healthy cells will be attacked. It has also proven to be relatively safe and well tolerated in its initial clinical trial of 26 patients. It is quickly flushed from the body, leaving less possibility of any toxic effects or drug accumulation with each cycle of treatment.
For more information on either of these two drugs, you can get the full article from the American Association of Cancer Research here.
The final, and what I believe is a truly novel approach to cancer treatment is the development of a virus that infects and kills cancer cells while leaving normal cells unharmed. According to an abstract published at EurekAlert!, David Kirn and colleagues at Jennerex Biotherapeutics in San Francisco have managed to genetically engineer a new virus that has shown an antitumor effect in studies done on mice and rabbits. Additional testing has been done on human tissue, and the group believes that the concept could be ready for clinical trials in humans. This process of creating viruses as potential cures for disease is called virotherapeutics. For a much more detailed description, and link to the article that was published by this group, click here. I, unfortunately, am not scientifically minded enough in order to read and regurgitate the findings in this article, but maybe you are!
Certainly, these three instances alone give me hope that scientists are thinking “outside the box” and finding new ways to treat this disease. Cancer is scariest to me because it cannot be identified as something that you “catch.” It’s something that’s written into your DNA on the day you’re born, and may or may not be activated at some point in your lifetime. Certainly, we can avoid things like cigarette smoking as an attempt to prevent the occurrence of certain cancers linked with environment, but as Dana Reeve showed us, even preventative measures is not a guarantee that cancer won’t strike.
Do you think there will be a cure for cancer in our lifetime? Will we ever really call it a “cure?” By using that word, do we associate an assumption that the cancer will never return? Is treatment more appropriate? If we do manage to stamp out cancer, do you think there is another disease that might be worse on the horizon? How will it effect life expectancy?
Let me know your thoughts!
(1) See “Experimental Cancer Pharmaceuticals under Trial,” edited by Greg Lester, American Association for Cancer Research.
