Evidence of Y Chromosome Long Non-Coding RNAs involved in the Radiation Response of Male Non-Small Cell Lung Cancer Cells Tayvia Brownmiller Non-small cell lung cancer (NSCLC) is the number one cause of cancer related mortality in the United States and worldwide. Advanced and therapeutically resistant lung tumors contribute to the high rate of mortality from NSCLC, therefore there is a need for new methods of diagnosing and treating this disease. Long non-coding RNAs (lncRNAs) have been shown

more »

... be a crucial component of human molecular biology, regulating nearly every cellular pathway from chromatin condensation to transcription and translation. Furthermore, many lncRNAs have been classified as oncogenes or tumor suppressors, highlighting the various molecular mechanisms they are involved in regarding the formation and progression of cancer and their use as prognostic and diagnostic biomarkers has been proposed in numerous cancers, including NSCLC. Our group has discovered, for the first time, a three member family of Y chromosome lncRNAs (linc-SPRY3-2, lin-SPRY3-3, and linc-SPRY3-4) which regulate NSCLC cell response to ionizing radiation (IR). Briefly, the linc-SPRY3 family demonstrated a dose dependent induction of expression following exposure to IR in male radiosensitive NSCLC cell lines, but not in male radioresistant cell lines. This difference was revealed to be due to loss of the Y chromosome in the radioresistant cell lines. Using gain-of-function and loss-of-function experiments, we demonstrated statistically significant changes in cell viability and apoptosis in vitro. Furthermore, in vivo tumor growth delay assays showed a more radioresistant phenotype in tumors with knockdown of the linc-SPRY3 RNAs versus control tumors. We hypothesize linc-SPRY3-2/3/4 mediate their tumor suppressive effect via sequestration of the RNA binding protein IGF2BP3 demonstrated by CLIP and RNA degradation assays. Moreover, DNA FISH and bioinformatic analysis revealed a trending negative correlation in patient survival between loss of the Y chromosome and linc-SPRY3-2/3/4. These findings suggest that the linc-SPRY3 RNAs function as tumor suppressors by promoting cell death following IR through interactions with IGF2BP3, and could have potential as biomarkers in male NSCLC. iii Acknowledgements The work presented in this dissertation is the culmination of seven years of blood, sweat and many many many tears, and would not have been possible without the support of a number of individuals. First and foremost, I need to thank my mentor, Dr. Ivan Martinez. Though there have been numerous times where I was frustrated beyond belief with both you and/or the research, this would not have been possible without your guidance. This was a learning curve for the both of us, which we have both admitted multiple times throughout this process, and I wholeheartedly believe we are both the better for it. Your unbelievable mentorship has prepared me for whatever comes next and I hope one day I get the chance to do for others what you have done for me.