Dr. Jane Cavender, professor of biology and chair of the biology department, held a presentation entitled “What are these new cancer drugs?” as part of the Community Enrichment Series.
“Talks like this hopefully give you a better idea of what [the medications] doing and how to take care of yourself,” Cavender said. She began the lecture by covering what cancer is.
Cavender, whose background is in genetics, explained that our body is constantly dividing and copying new cells from older cells. “No wonder we’re so tired. We’re doing this stuff all day,” Cavender said.
Next Cavender had the audience consider cells that divide, such as white and red blood cells, and cells that do not divide, such as neurons and cardiac cells. She explained that heart cells do not divide, which is why no one has cases of heart cancer.
When the cell copies, mistakes can sometimes occur in the process. Cavender compared this to dropping a stitch while knitting. “If you’re anything like my knitting, you make mistakes,” she said. Some mistakes typically occur while cells are dividing and making copies.
The difficulty occurs when numerous mistakes are made in cell division. Cavender said that cancer is typically a disease of older people because of this. For most individuals 100 million to one billion cells divide for every one mistake in cell division.
When mistakes do occur, Cavender compared this to having an error in the instruction manual.
“Let’s say you’re two year old ate a page out of your instruction manual, and so you have to skip from step one to step four,” she said. The error can result in a non-functioning worker or a hyperactive worker. The workers will then produce a different protein than they are supposed to produce.
The body also has methods for eliminating tumor cells. Cavender explained that tumor cells are slightly altered versions of ourselves, such as having two heads instead of one.
“We have editors and checkers, so even if we make mistakes, those can be fixed,” Cavender said. Cells survey and remove mutations, which can prevent cancerous cells from replicating.
She gave specific examples of environmental factors that can affect whether or not an individual will develop cancer. Sunburn, for example, damages DNA. When a skin peels from sunburn this means that cells have activated the death process, indicating damage to the DNA has intensified.
X-rays also affect an individual’s DNA. Cavender said that now doctors will track the number of x-rays a patient receives in a year to reduce overexposure to radiation. Smoking has also been shown increase the likelihood of developing cancer.
Cavender’s own work at Elizabethtown College focuses on viruses that induce tumor. She said that her work is at the minute level of examining individual cells that can either inhibit or exacerbate the spread of a tumor in the body.
“I actually like to find out who is in the cell, and why they’re there,” Cavender explained. She will take model cells and inject them with the virus in order to understand the process when the virus changes the cell to a tumor.
Carbonyl reductase 2 (CBR2) specifically interests Cavender in her research. Only 55 percent of non-small cell lung carcinomas express this gene. “So, my question is why don’t all cells have this,” Cavender said.
Cavender’s research functions independently of any company outside of the College. She currently works with an organic chemist in examining the effects of cancer on specific cells. “Once we would publish this information, a pharmaceutical company could pick it up and work with it,” Cavender said.
Her interests also focus on the effects of genetics on different cancer treatments. A largely influential factor in developing cancer is familial genetics. “Some people have a worse deck of cards than others,” Cavender said.
Cavender covered some of the current drugs being used to treat cancer. Topoisomerase works to relax the cell and helps the DNA replicate. Topo II drugs work to stop this process. “If topo can’t work, we can’t unwind the cord and replicate the DNA,” Cavender said.
Anti-metabolites mimic normal structures in the cell, but make DNA fragile and susceptible to breaking. Breakage of the DNA prevents cell replication, which hinders the spread of tumor cells throughout the body.
Methotrexates work as what Cavender referred to as fake folinic acids, which are part of the B vitamin family. Going back to her knitting example, Cavender explained that methotrexate stops the body from making more yarn. The DNA does not replicate, which stops the spread of cancerous cells.
Poly ADP ribose polymerase (PARP) inhibitors also prevent the cell replication. PARP repairs niches in DNA. If PARP is inhibited, the single break will lead to a double break, which will be lethal for a tumor cell.
Cavender also covered homeopathic methods of treating cancer. Studies have been done demonstrating that eating prunes or lemons can help treat cancer. “I always think there’s more than a grain of truth sometimes to old wives’ tales,” Cavender said.
However, treatments, whether drug regimes or homeopathic, can be more or less effective to an individual based upon his or her genetics. Cavender encouraged the need for genetic testing. “This is where we’re hopefully getting to [cancer treatment] being less toxic,” she said. “We’re not just hitting everybody with all guns when it’s not necessary.”
She included that genetic testing can be expensive, but insurance companies are increasingly covering genetic testing for individuals.
Cavender gave the example of a friend’s son who is autistic, and his medication was not effective. In order to help doctors refine what drug combinations to give the child, the family used genetic testing. The family’s insurance company paid for the testing. Cavender attributed this to the amount of time shortened for doctors in discovering the best medication for patients.
What she referred to as designer drugs treat individuals based upon how their genetics determine their reaction to a medication. “This is where the science and genetics have to work together,” Cavender explained.
