Gabriella Chatman & Dr. Kacper Rogala NCI Diversity Supplement | Project Summary | March 31, 2024 Many RAS-transformed cancer cells are able to escape cytotoxic chemotherapy and survive in near-starvation conditions. One adaptation making them hard to kill is their ability to scavenge extracellular proteins and recycle the cellular components using autophagy, both of which are then digested in lysosomes to recover free amino acids. Nutrient transporters, such as SLC38A9, have been shown to act as gates that release digested nutrients back into the cell, which in turn restarts cellular growth programs. Intriguingly, RAS-transformed pancreatic cancer cells with SLC38A9 knocked-out are unable to efficiently form tumors, which presents a novel therapeutic idea of targeting a metabolic vulnerability. In this R00 supplement project, we will expand on that initial discovery from pancreas cancer. First, we will explore whether other cancer types that carry mutations in RAS and Wnt signaling pathways can also perform nutrient scavenging via macropinocytosis. Second, we will test whether an inducible genetic knockout of SLC38A9 hampers growth of macropinocytosis-positive cancer cells that otherwise grow successfully on an extracellular protein diet. Knockout of SLC38A9 will lead to entrapment of macropinocytosis-derived amino-acids within the lysosomes, and our expectation is that this treatment will impair the growth of tumors addicted to protein scavenging, while sparing normal cells that lack this requirement. This supplement will allow us to broadly generalize the anti-cancer strategy that we are establishing in the R00 parent grant. Importantly, the supplement will help us recruit and train a promising post-baccalaureate student who has a great potential for a future career in scientific research.