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SU physiology students reap top awards
Author: Media & communication, Faculty of Science
Published: 06/10/2016

Two physiology students from Stellenbosch University (SU), Tanja Davis and Jenelle Govender, were the winner and runner-up respectively of the prestigious Wyndham competition organised by the Physiology Society of Southern Africa (PSSA).

The Wyndham competition is the highlight of the annual PSSA conference and offers postgraduate students from all South African universities the opportunity to present and defend their research work for an international audience. This year, 30 students competed.

Tanja (winner) and Jenelle (runner-up) are both PhD students in Prof Anna-Mart Engelbrecht's Cancer Research Group in the Department of Physiological Sciences at SU. The focus of the research group is to explore new avenues of chemotherapy and adjuvant treatments.

Prof Engelbrecht says this type of research is important because while powerful drugs such as doxorubicin (DXR) has proven to be successful in treating cancer, it induces various side effects such as nausea, vomiting, the suppression of blood cell production in bone marrow and cardiotoxicity.

"Another major concern is the fact that cancer cells are becoming increasingly resistant to these drugs," she warns.

Tanja received the award for her presentation on the role of the human AHNAK protein in a cancer cell's response to DXR, a drug  commonly prescribed to breast cancer patients.

She explains: "Many women suffering from breast cancer respond differently to treatment and where a particular treatment works well for one person it may not have the same effect in another person. This is because not all cancers are the same and can thus respond differently to the same treatment. We already knew that the AHNAK protein might be involved in breast cancer, but it was unclear how and whether it could affect how the cancer cell responds to chemotherapeutic treatment."

Tanja's research has delivered important insights into how breast cancer can be resistant to treatment: Her research found, inter alia, that the AHNAK protein played an important role with regards to cell death and the cell cycle the moment DXR is introduced. Most importantly, she found that the AHNAK protein fulfilled this role only in breast cancer cells that were resistant to DXR.

"When we understand how a cancer will respond to a particular treatment, adjustments can be made to improve the outcome for the patient," she explains.

Jenelle's research about the toxic side-effects of DXR showed that pre-treatment with melatonin could protect the heart.

Melatonin is naturally produced by the pineal gland in the brain and is responsible for regulating the body's sleep-wake cycle. But melatonin is also a potent antioxidant and has been shown to influence the functioning of mitochondria in the cell and to stop cancer growth whilst having a protective effect on the heart.

The aim of Jenelle's research was to pinpoint the exact mechanisms by which melatonin protects the mitochondria in the context of DXR-induced cardiotoxicity: "The heart has a high energy demand and 90% of this energy is produced by mitochondria. DXR specifically targets mitochondria, causing them to malfunction which can eventually lead to cardiac defects and heart failure."

The results of her study strongly indicated that pre-treatment with melatonin can protect the heart against the toxic effects of DXR by improving the functioning of the mitochondria and thus increasing the survival of heart cells.

On the photo, Jenelle Govender (left) and Tanja Davis