Molecules and compositions are described for use in the treatment and prevention of pro-inflammatory conditions. HDL-related molecules, including ApoA-I, bovine HDL and HDL mimetics, in particular, are demonstrated to prevent UV-induced cell death and oxidative stress in skin cells and to inhibit tumor growth and development in a variety of cancers. HDL-related molecules can be used as an oral supplement and in other compositions to prevent or treat pro-inflammatory skin conditions and systemic proinflammatory conditions, including Alzheimer's disease and various cancers.