According to the embodiments described herein, a SUMOylation inhibitor compound comprising a singleton scaffold is provided. In some embodiments, a method for inhibiting a SUMOylation enzyme in a cell is provided. Such a method may include administering a SUMOylation inhibitor compound to the cell. In some aspects, the SUMOylation enzyme is SUMO E1 or SUMO E2. In some aspects, the method may be used to inhibit a cancer cell in vitro (e.g., grown in culture) or in vivo (e.g., as part of a tumor in a subject). In other embodiments, a method for treating a cancer, degenerative diseases and viral infection is provided. Such a method may include administering an effective amount of a pharmaceutical composition to a subject having the cancer. The pharmaceutical composition may include a singleton SUMOylation inhibitor compound. In some embodiments, the method for treating a cancer may further comprise administering one or more DNA-damaging therapy in combination with administration of the pharmaceutical composition.
