Provided herein are compositions for lowering intracellular pH in a cell or population of cells from a subject comprising contacting the cell or population of cells with a therapeutically effective amount of 5-nonyloxytryptamine or a pharmaceutically acceptable salt, solvate, stereoisomer, or derivatives thereof. These compounds are useful for acidification of cells, including cancer cells, which induces apoptosis and cell necrosis. Methods of use of these compounds, including in pharmaceutical compositions in conjunction with other biologically active agents, in treatment of cancers, including glioblastoma and related neuronal cancers are also included.