K103

K103 is an inhibitor discovered from the screen that is an analog of the serotonin antagonist benzazocine. K103 exhibited inhibition of SHIP homologues, labelling it a pan-SHIP1/2 inhibitor, but the molecule had no effect on another 5' inositol phosphatase, OCRL. In line with the "two PIPs hypothesis", the molecule exhibited significant anti-tumour effects against a variety of cell lines, particularly breast cancer cells. Additional studies with K103 revealed that inhibition of SHIP1/2 in multiple myeloma cells resulted in G2/M cell cycle arrest followed by extensive apoptosis via activation of the caspase cascade. K103 fits the commonly used small molecule agent property profile, but while this work was being conducted, it was discovered that K103 caused psychoactive effects in mice, which limited the utility of the molecule in vivo. Therefore, certain synthetic studies were conducted on this tryptamine to identify the features that needed to be present in the molecule to maintain pan-SHIP1/2 inhibition in order to design an inhibitor with favourable pharmacodynamic properties and an improved side effect profile.