Embodiments of the invention relate to a vector system that allows one to induce expression of therapeutically relevant genes in mammalian cells. Such a vector system may be useful for medicine and in the pharmaceutical industry. A vector comprises base structures suitable for expression in mammalian cells as well as either the whole of or parts of the gene promoter of human Major Vault Protein (MVP), also known as LRP (Lung Resistance Protein) as well as a gene encoding a therapeutic protein or non-translated RNA. As the MVP promoter is inducible by therapy (for example, but not limited to, chemotherapy or hyperthermia), the vector system provides combinations of therapeutic methods with gene therapy in a controlled fashion, resulting in more efficient treatment of tumor diseases.