Since its discovery, chemotherapy has proved to be a valuable tool for treating cancers of several kinds, but with a major downside. Chemotherapy destroys cancer cells, but can also destroy healthy cells such as the one in hair follicles to cause baldness, and the ones that line the stomach to cause nausea.
In a significant finding, scientists at Caltech may have developed a better solution: genetically engineered, sound-steered bacteria that seek and kill cancer cells.
The findings published in Nature Communications demonstrates how a specialized strain of E.coli bacteria seeks out and invades cancerous tumors when injected into a patient’s body. On reaching their destination, the bacteria can be prompted to produce anti-cancer drugs with ultrasound pulses.
The goal of the technology is to leverage the ability of engineered probiotics to invade tumors, while use ultrasound to activate the tumors to discharge potent drugs inside the tumor, stated one of the research associates.
To initiate the work, it involved using a strain of E.coli called Nissle in 1917, which is approved for use in humans. Once injected into the bloodstream, the bacteria spreads throughout the body. The immune system of the patient then destroys them, except for those bacteria that colonize cancerous tumors, which provide an immunosuppressant environment.
Importantly, to convert the bacteria into a useful instrument for treating cancer, the team engineered for the bacteria to contain two new sets of genes. One set of genes is used to produce nanobodies, which are therapeutic proteins that switches off the signals a tumor uses to prevent an anti-tumor reaction by the immune system.
The presence of the nanobodies allow the immune system to attack the tumor. The other set of genes works like a thermal switch for turning on the nanobody genes when the bacteria gets to a specific temperature.