Project 3 comprises a collaborative effort between the University of North Carolina at Greensboro (chemistry via the Nicholas Oberlies Lab), Mycosynthetix, Inc. (mycology), and Columbia University (biological evaluation via the Brent Stockwell Lab). It is hypothesized that anticancer drug leads with novel structures will be obtained from filamentous fungi. Hence, the goal of Project 3 is the discovery of structurally diverse and biologically active compounds on a scale that facilitates drug development. To do so, the three specific aims can be summarized as: Specific Aim 1: Select and culture fungi from the Mycosynthetix library, focusing on unusual cultures and those likely to produce promising leads. Specific Aim 2. Dereplication, Isolation and structure elucidation of bioactive lead compounds. Specific Aim 3. Test samples for oncogenic-Ras selective lethality and novel cell death mechanisms using engineered tumor cells. Project 3 has been revised per the helpful suggestions of the reviewers of the initial application. The three aims for Project 3 work in an iterative manner toward anticancer leads, with unique skills in mycology (Aim 1) providing samples for natural products chemistry (Aim 2) that are evaluated for biological activity (Aim 3). Importantly, this latter aim will focus on compounds that are synthetic lethal with oncogenic Ras. The Ras oncoproteins (K-Ras, H-Ras, N-Ras) are of paramount importance in cancer biology. They were discovered over 30 years ago, but have been resistant to direct targeting with small molecules. Thus, despite the fact that the KRAS gene is mutated in ~20% of all tumors, and >95% of pancreatic cancers, there is no therapy for treating mutant KRAS tumors. Compounds that show increased potency and lethality in tumor cells with oncogenic Ras are likely to exhibit an increased therapeutic index, and to reveal mechanisms for targeting tumors harboring mutations in the three Ras genes (HRAS, NRAS and KRAS). The resources of the Program will be utilized for pushing the best leads towards preclinical development. Besides the skills of the other Projects and Cores, this will include close interaction with our corporate partner, Eisai Inc (Andover, MA), who has a successful track record of developing anticancer natural products. The primary purpose of this part of the program project is to discover new cancer chemotherapeutic agents from cultures of filamentous fungi. In order to do this, our group will perform chemical and biological studies in a coordinated manner with the other components of this project.