ChemSemBlog

This week’s speaker was Amanda B. Hummon, who is currently teaching special topics in Biochemistry and Notre Dame. Some of her publications have appeared in premier journals, such as Cancer Research and she is currently researching analytical chemistry and cell and molecular biology. Dr. Hummon presented on colon and rectal cancer which we learned was very different and shouldn’t be put together. Her presentation was organized, had good audio with clear voice, went quickly, and was well explained. I found this topic to be very interesting I learned of the process that it takes when determining a tumor in the colon and rectal area.

Some new things that I learned were the characteristics of cancer cells, oncogenesis, and the difference between colon and rectal cancer. Cancer cells have proliferation, insensitivity to growth signals in the body, angiogenesis (formation of new blood vessels that grow into the tumor, giving it nutrients and oxygen to assist its growth), and WNT signaling (describes a network of proteins well known for their roles in embryogenesis and cancer). When looking at cancer cells they focus on the disease of the genome, DNA, RNA, protein, the network, function, and pathway.

Some of the projects that Dr. Hummon performed involved examining transcriptional deregulation in primary colon and rectal adenocarcinomas. They found that in colon aneuploid adenocarcinoma there were 58 chromosomes, while the normal diploid is 48 chromosomes. In the cancer cell some chromosomes had more than two copies and they gathered this information using comparative genomic hybridization process.

Other activities that they performed involved taking colon and rectal samples from patients in whom they compared the tumor versus the mucosa and their gene expressions. They found 17 genes having a fivefold difference between tumors and mucosa. The immune genes were expressed differently and the difference could be clearly seen. They also found the genes that turned on, trying to fight the cancer.

When looking at the difference between colon and rectal cancer, out of 5,000 genes only 400 changed in the same direction. This information showed that medicines treating these cancers should be prescribed separately rather than together, which is currently being done. In oncogenesis, the process of malignant transformation leading to the formation of a tumor, it was found frequently expressed in the cancer system that turn on specific amplifications. They examined 71 samples and able to narrow the amount of genes down using microarray, homology, validating them with RTPCR, and gene splicing with RNA. They found that siRNA successfully reduced expression of assays of mRNA resulting in the loss of function. Dr. Hummon and her research group was then able to identify nine genes that reduced the cell viability greater than twenty percent.

Many students seemed to enjoy this topic as well as the presentation. They listened attentively and asked many questions at the end, which were answered well. The presentation did encourage me to learn more about this topic and it would be appealing to do extra research on this topic, such as doing this same study or process with other tissues and organs. Dr. Himmon didn’t really speak much about her school of graduate studies, but I’m sure she would have been available to answer questions on that topic if asked. This was an interesting topic on the cancer cells and the genes involved dealing with colon and rectal cancer.

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