Compositions and methods of treating a subject with cancer are described. The methods include administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising a compound with the dual characteristics or restoring function of the c-Cbl ubiquitin ligase in cancer cells and in also worsening sublethal lysosomal dysfunction, preferably in combination with an agent capable of making cancer cells more oxidized. The pharmaceutical composition can be administered with an additional therapeutic agent or agents such as an agent that represents an accepted standard of care for the treatment of a particular type being treated. The methods can be used for treating a wide variety of different kinds of cancers, such as brain tumors, breast cancers, melanomas, breast cancers and lymphomas. The compositions and methods have the characteristics of enabling simultaneous regulation of multiple proteins known to be critical in cancer cell function, of targeting cancer stem cells and of enhancing sensitivity of cancer cells to the effects of tamoxifen and other anticancer agents.