The invention, at least in part, is directed to methods for enhancing delivery of therapeutic agents, such as macromolecules and drugs, into the interior of tissues, such as solid tissues or tumors. The method initially uses an apoptosis inducing agent, such as paclitaxel, in doses which create channels within the tissues, and enhance the penetration of therapeutic agents to the interior of the tissue. Current methods of treating tissues are often not effective because the therapeutic agents are not delivered to the interior of the tissue. By using the methods and the compositions of the current invention, therapeutic agents can be delivered to the interior of the tissue.