Phd in GENETICS AND MOLECULAR BIOLOGY

Thesis title: Exploring the contribution of a-tubulin N-acetyltransferase 1 (ATAT1) and acetylated microtubules in mitotic and migration processes in cancer cells.

Tubulin post-translational modifications (PTMs) contribute to microtubule diversity and regulate the functions of these structures within cells. Among the different PTMs, the acetylation of-tubulin occurring at lysine-40 (K40) is particularly well characterised from a biological perspective. K40 tubulin acetylation is known to regulate diverse cellular functions often deregulated in cancer, as microtubule dynamics, cell migration and cell division. Alpha-tubulin N-acetyltransferase 1 (ATAT1) is the enzyme responsible for -tubulin K40 acetylation, and it is implicated in processes that depend on microtubule function, including cell motility, formation and function of the mitotic apparatus, cytoskeletal organization, and intracellular trafficking. Notably, emerging evidence suggests that ATAT1 may also play significant roles in cancer biology. A range of bioinformatics tools were applied to investigate the expression patterns of ATAT1 in lung cancer; we found that the expression of ATAT1 is upregulated in human NSCLC samples compared with normal tissues and there is a negative correlation between ATAT1 expression level and the survival rate of lung cancer patients. Based on this rationale, the objective of this study was to investigate the role of MT acetylation and ATAT1 in tumour biology. In order to achieve this objective, by using NSCLC ATAT1-silenced models, I investigated whether ATAT1 directly modulates cell division and migration, both hallmarks of tumour progression. Moreover, experiments with a non-acetylatable form of α-tubulin were performed to discriminate tubulin acetylation function from ATAT1 function. Obtained results suggest that ATAT1 and acetylated tubulin play significant role in pathways in the build-up and function of the mitotic apparatus, with some cell type-specificity reflecting intrinsic genetic features of the cells, yet converging on originating chromosome segregation errors that are likely to generate and increase genetic instability in cancer cells, and also influence the migration capacity and adhesion properties of the cells, which is often deregulated in cancer. Interestingly, in the latter process, ATAT1 may play additional functions beyond its acetyltransferase enzymatic activity, laying the ground for further studies of the relevance of this protein in cancer.