Provided herein, inter alia, are compositions and kits comprising a bacterial cell and a tumor penetrating agent. Also provided are methods of treating cancer in a subject including the step of administering to the subject an effective amount of a bacterial cell and a tumor penetrating agent. Provided are methods of stimulating an immune system in a subject. The methods include administering to the subject an effective amount of a bacterial cell and a tumor penetrating agent. Also provided are methods of enhancing delivery of an anti-cancer agent to a tumor cell including the step of contacting the tumor cell with a bacterial cell, a tumor penetrating agent and an anti-cancer agent.
