Described herein are compositions useful in anticancer treatment and prevention. The compositions are composed of (a) an O2-aryl substituted diazeniumdiolate and (b) an amphiphile, wherein the amount of amphiphile is sufficient to produce a liposome or micelle. The compositions described herein provide numerous advantages such as increased solubility and stability of the O2-aryl substituted diazeniumdiolate in vivo. The compositions also do not induce hypotension. Methods for using the compositions in anticancer treatment and prevention are also described herein.