Yonca Bassoy wins Best Thesis and the cover of EMBO J: cancer and ER-mito contacts

Esen Yonca Bassoy, who recently graduated with High Distinction from her Ph.D. studies in the group of Denis Martinvalet this past November, has won the “Best Thesis of 2016” award from the Doctoral School of Biological Medicine at the University of Geneva.

 Yonca’s doctoral work focused on the analysis of glioblastoma cancer stemlike cells (GSC), an aggressive brain of tumour cell type that is resistant to chemotherapy. In a first publication in Plos One, Yonca found that GSC are more susceptible to being killed by special cells of the immune system called cytotoxic or “killer” T cells, than a closely related type of brain tumour cell called GDC. These results imply that immunotherapies that stimulate killer T cell activity may an effective alternative to chemotherapy against this aggressive type of glioblastoma. In a follow-up study, published this month in the EMBO Journal and entitled “ER–mitochondria contacts control surface glycan expression and sensitivity to killer lymphocytes in glioma stem‐like cells”, Yonca showed that the increased susceptibility to immunogenic killing was related to the reduced amount of certain types of sugars, called glycans, found on the surface of GSCs. She further demonstrated that this reduction in surface sugars occurred because GSC have fragmented mitochondria and a reduced number of contacts between the endoplasmic reticulum (ER) and mitochondria, respectively the major secretory and metabolic compartments of the cell. These results reveal several important new facets of cancer cell biology. First, they have identified a new function of ER-mitochondria contact sites, tiny structures that allow communication between these two compartments, or organelles, and whose misregulation has been linked to several other types of diseases. Second, they suggest that the sugar composition of the cancer cell surface is a major determinant in whether it can be recognized by immune system, a finding with deeper implications for the design of novel immunotherapies. These exciting discoveries were featured on the cover of this month’s EMBO Journal as well as in a News and Views article in the same issue.

 Well done Yonca! Wishing her all the best in her new post-doctoral position in the Department of Pathology and Immunology at the University of Geneva.

Posted by: P. Nunes-Hasler

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