2 min readT-cells could be Made into Better Cancer Killers by Increasing Their Protein Production
Charleston, SC — A team of scientists from Hollings Cancer Center at the Medical University of South Carolina (MUSC) has developed a novel flow cytometry technique that can, for the first-time, quantify protein production in T-cells. T cells are immune cells that surveil the body and can effectively target and kill cancer cells. However, when T cells are in the vicinity of a tumour, cancer cells sap their energy, leading to a decrease in their protein production. This change leads to T cells losing their tumour-killing ability.
The new technique, developed by the MUSC team, can be used to monitor protein production in T cells and understand how it becomes depressed in the tumour microenvironment. Interventions could then be developed to restore T cells’ protein production and ability to control tumor growth. The team, led by Dr. Jessica E. Thaxton, recently reported its findings in a priority brief in Cancer Immunology Research. Thaxton is an assistant professor in the departments of Orthopaedics and Physical Medicine and Microbiology and Immunology at MUSC and a member of Hollings Cancer Center, a National Cancer Institute designated cancer center.
“This study reveals our first attempt at trying to understand how T cells undergo the process of making proteins,” explained Thaxton. “Before this paper or before this technology, scientists had very little idea how much protein T cells make. It was a shot in the dark. But now we have quantitative data that shows how much protein T cells make, and we can begin to ask questions like, ‘Which proteins?’ and ‘How are they made?'”
In the past four years, the team observed more than 50 human tumours, and in most tumors, they noticed the existence of T cells that made very little protein. This finding led them to surmise that there are T cells unable to make proteins residing in tumours. According to Thaxton, the new technology will help them to monitor these T cells and reawaken their protein production machinery and cancer-fighting ability.
“This paper establishes that T cells that are able to make protein in tumours have phenomenal ability to control tumour growth,” explained Thaxton. “We ultimately want to remodel the existing T cell population in tumours, and that is really where our laboratory is headed.”
To understand more fully protein production in T cells in tumours, the scientists used two different types of signalling molecules (cytokines) called IL-15 and IL-2. It has been established in other studies that T cells treated with IL-15 control tumour growth very well, but those conditioned with IL-2 do so poorly. The team found that T cells conditioned with IL-15 were able to make proteins in the tumour microenvironment and in tumours, whereas IL-2 conditioned T cells experienced diminished protein production in tumours.
These results will help scientists to understand how they can reawaken tumour T-cells and increase their protein production, thereby enhancing their ability to control tumour growth. Thaxton believes that a simple strategy of combining a modulator that changes the way that T cells generate energy will allow T cells to experience sustained protein production in tumours and produce more effective immunotherapy treatments for patients.
Unlike many current immunotherapies, which can be quite expensive, this approach would be cost-effective and thus a more realistic strategy for treating cancer patients from all walks of life.
Thaxton believes that the current study is the very first set of experiments that begins to delineate the role of protein production in anti-tumour immunity.
“There is a lot more in store that we are now uncovering from this basic first set of experiments,” explained Thaxton. “This paper is a model of our first insight into how protein production is regulated in T cells, and we are working on which parts of the regulation are the most important for tumour control.”
Article adapted from a Medical University of South Carolina news release.
Publication: Remodeling Translation Primes CD8+ T-cell Antitumour Immunity. Hurst, KE et al. Cancer Immunology Research (February 19, 2020): Click here to view.