Synthetic Cells Synthesize Therapeutic Proteins inside Tumors

Protocells, artificial cell-like particles, capable of autonomously synthesizing RNA and proteins based on a DNA template, are emerging platforms for studying cellular functions and for revealing the origins-of-life. Here, we show for the first time that artificial lipid-based vesicles, containing the molecular machinery necessary for transcription and translation, can be used to synthesize anti-cancer proteins inside tumors. The particles were engineered as stand-alone systems, sourcing nutrients from their biological microenvironment to trigger protein synthesis. When pre-loaded with template DNA, amino acids and energy-supplying molecules protocells synthesized, up to 2×10(7) copies of superfolder green fluorescent protein (sfGFP) were synthesized in each liposome. A variety of proteins, having molecular weights reaching 66 kDa and with diagnostic and therapeutic activities, were synthesized inside the particles. Incubating protein producing particles, encoded to secrete Pseudomonas exotoxin A (PE) with 4T1 breast cancer cells in culture, resulted in killing of most of the malignant cells. In mice bearing 4T1 tumors, histological evaluation of the tumor tissue after a local injection of PE-producing particles, indicating robust apoptosis. Protein producing particles are synthetic-biology platforms capable of synthesizing therapeutic proteins on-demand.