Spiropyrrolizidine and piperazine derivatives: Synthesis and evaluation on kras expression levels in human colon cancer cells

Abstract

KRAS-driven cancers are notoriously difficult to treat due to poor pharmacodynamics of downstream inhibitors and resistance to anti-EGFR drugs. IMP-1 is a post-transcriptional regulator of KRAS mRNA. As a novel therapeutic approach, the targeting of the IMP-1-KRAS mRNA complex with a spiropyrrolizidine derivative (UNBC152), was studied. LC-MS analysis of UNBC152 indicated presence of impurities. The purpose of this study was to synthesize UNBC152 and determine the responsible bioactive molecule within the impurities. LC-MS and TLC suggested the presence of a bioactive [3+3] cycloaddition side product (SPOPP) in UNBC152. SPOPP suppressed KRAS expression in human colorectal cancer cells. Fluorescence polarization determined that SPOPP did not impact the IMP-1-KRAS mRNA interaction. SPOPP induced G2/M cell cycle arrest as shown by flow cytometry. MTT assay confirmed the SPOPP-induced growth inhibition in SW480 (IC50 = 4.17 μM) and HT29 (IC50 = 6.76 μM). These findings represent a first reporting on the bioactivity of SPOPP. References XIX Chapter 1-Introduction First and foremost, I would like to thank my supervisor, Dr. Chow Lee for giving me the opportunity to work in an excellent cancer research lab. Your support and guidance throughout the past few years have helped me grow substantially as a researcher. I would never forget the time spent in this lab, as it also helped me grow personally. To Dr. Tina Bott, my co-supervisor, I would like to thank you for your patience. You have always been a great mentor for organic chemistry, from undergrad till now. Your help has been tremendous, especially during the initial syntheses. To Dr. Maggie Li, thank you for joining me on the front lines in the assay screens to help solve the UNBC152 puzzle. You always had wise words during my quandaries. I would like to acknowledge Dr. Kerry Reimer for passing on excellent theoretical knowledge for HPLC purifications. I would like to acknowledge Dr. Guy Plourde for always inspiring me to think about the mechanistic nature of reactions. I would like to thank Dr. Hossein Kazemian for being a gracious host of the Northern Analytical Lab. Thank you to Charles Bradshaw for keeping the HPLC running. To Dr. Liz Dunn and Dr. Kaila Fadock, thank you for the technical knowledge on NMR. To Sebastian and Corbin, thank you for all the great times in and out of the lab; I am fortunate to have met the both of you. To my other close friends, Cale, Laura, Levon, Jonah, Aaron and Joshua, thank you for always being around, even when I seemingly drop of the face of the Earth to do research. Last but not least, I would like to thank my parents. To my mother Kit Pang, thank you for always believing in me, especially when I was meandering through different educational paths. To my late father, David Liu, thank you for supporting me throughout the years. I miss you more than you would ever know.