Abstract
Cancer is the leading cause of death worldwide, and of that, lung cancer is the deadliest. Non-small cell lung cancer is the most common of the lung cancers, and tends to be aggressive, difficult to treat and resistant to many chemotherapeutics. This can be due in part to factors such as increased levels of chromosomal instability (CIN), which describes the continuous damage that occurs every cell cycle due to errors in mitosis or DNA damage repair pathways. This instability can occur for a variety of reasons, however the one examined in this project is increased levels of Y box binding protein 1 (YB-1) in adenocarcinoma cells. This is due to YB-1’s role in control of cytokinesis, the end stage of mitosis. YB-1 is highly involved in the stabilisation of many complexes key for correct chromosomal segregation and division of the cytoplasm. This ties into YB-1 and the already observed link to drug resistance, specifically to the taxane paclitaxel (PTX). To elucidate the connection between YB-1, chromosomal instability and resistance to paclitaxel cell proliferation assays using an H1299 tet-one YB-1 stable cell model with inducible YB-1 were undertaken to see if there was a difference in cell response to the drug with high or low YB-1 levels. Following this it became clear there was a need to create single cell clones from the polyclonal model. Two clones were created and checked to ensure they had both the inducible YB-1 and the fluorescent tags via qPCR, western blots, and use of the fluorescent microscope. The proliferation assay was then repeated on these cell lines, as well as live cell imaging on cells dosed with paclitaxel to examine the features associated with chromosomal instability, micronuclei, nuclear budding and multinucleated cells. From these experiments it was seen that increased levels of YB-1 conveyed resistance to paclitaxel to one clone, and resulted in more features of CIN when examined with live cell imaging. This suggests that there is a plausible link between elevated levels of YB-1 leading to an increase in chromosomal instability as a mechanism for paclitaxel resistance.