Tricyclic guanidine alkaloids from the marine sponge Acanthella cavernosa that stabilize the tumor suppressor PDCD4 - Grkovic, T; Blees, J S; Bayer, M M; Colburn, N H; Thomas, C L; Henrich, C J; Peach, M L; McMahon, J B; Schmid, T; Gustafson, K R (Mar Drugs, 2014)