Extracellular vesicles (EVs) are lipid-bilayer membrane-enclosed structures that cells produce and use for intercellular communication. Within the context of cancer, EVs have been shown to enhance cancer development by delivering cargo from malignant cells to recipient cells to promote survival, proliferation, and invasion. In a previous project, I conducted a chemical screen alongside my graudate mentor and other undergraduates to determine kinases that were important to EV biogenesis. One hit was the JNK pathway, which decreased EV production when inhibited. I studied the pathway in further detail utilizing a variety of experimental techniques to establish its importance for EV generation, and I was able to conclude that JNK regulates EV biogenesis. Another facet of cancer development is oxidative stress, caused by reactive oxygen species (ROS). When unregulated, these highly reactive free radicals and molecules derived from oxygen can damage DNA, facilitate metastasis, and aid in cancer progression. Given that surrounding literature revealed that JNK is activated by ROS, I hypothesized a connection between ROS and EV production. This project aims to more directly uncover the impact of ROS on EV generation by manipulating ROS-related genes in vivo. To do this, I knocked down ROS generator genes such as Dual Oxidase (Duox) in Drosophila melanogaster. I quantified ROS levels by staining the dissected tumor tissues with an ROS probe to ensure that the genes were functioning as expected. Then, I stained the tissues for phospho-JNK as a proxy for ROS quantification and to measure JNK activity. Finally, I conducted live imaging of the tumor tissues to quantify EV generation. I anticipate that impairing ROS generation will inhibit JNK activation, subsequently leading to a decrease in EV production. Understanding how factors involved in cancer development function in relation to each other is crucial for discovering novel cancer therapeutics.

Extracellular vesicles (EVs) are essential mediators in intercellular communication secreted by cells to transfer bioactive cargo that lead to biological effects. The crucial roles EVs have in maintaining biological homeostasis are similarly found within cancer cells in the tumor microenvironment, where they promote cell growth/survival, invasion, and metastasis. Investigating methods to reduce tumor-cell derived EVs could provide substantial remedies for cancer patients. One pathway of interest in cancer is the cellular response to reactive oxygen species (ROS)—highly reactive molecules which tumor cells use for oncogenic signaling, to damage macromolecules, and drive tumor progression. Modulation of ROS levels may yield anticancer effects, but research about the role of ROS in EV biogenesis has not been conducted. To assess their connection, I used MDA-MB-231 human breast cancer cells as an in vitro model for EV biogenesis. My interest in ROS and EVs began when I assisted my graduate mentor in an extensive chemical screen and found kinase inhibitors that altered EV production via an EV isolation protocol. From these hits, I identified ROS-activated pathways that promote cancer progression as important players in EV production. I then tested if chemicals known to directly affect ROS alter EV production by isolating and quantifying EVs and by imaging their production from MDA-MB-231 cells. To provide a comprehensive understanding of the pathway, I validated upstream interactions of EV biogenesis by measuring the production of ROS using a chemical marker that emits green fluorescence when oxidized. From this data, I can determine if there is a direct interaction between ROS and EV production. An understanding of EV biogenesis and its connection to ROS and cancer progression may unveil new opportunities for novel cancer therapeutics.