The difficulty of getting cancer medicines in the right places and in the right quantities is just one of the many obstacles that slow cancer treatments. A new type of implant developed at Rice University solves both problems, carrying tiny “cellular machines” that produce and deliver continuous doses of anti-cancer chemicals, capable of completely removing ovarian tumors in mice in just one week.
The researchers who created this intriguing new type of cancer immunotherapy have nicknamed them “drug factories,” because once set up, they can produce the chemicals needed to get rid of tumors on their own. The implants are made up of tiny balls the size of a pinhead: they contain carefully selected cells encapsulated in a protective shell.
The research was published in the journal Science Advances.
Drug factories
These spheroidal particles are made to produce a natural chemical called interleukin-2, a cytokine that prompts white blood cells to come into action in the body's effort to fight cancer.
These spheres were tested for the first time in recent laboratory tests. The researchers 'threw' them into malignant tumors within the peritoneum, the membrane that lines the abdominal cavity. Here, drug factories were shown to selectively generate a concentration of interleukin-2 within tumors, without ending up elsewhere.
The experiments carried out
The first evidence was followed by research in mouse models of advanced ovarian and colorectal tumors. The spheres made a splash, demolishing tumors in rodents in just under a week. Most importantly, they delivered only high dosages of the drugs directly to the tumor site, avoiding toxicity to healthy cells.
“We only administer them once, but the drug factories continue to distribute what is needed, where it is needed. Until the cancer is eliminated,” he says Omid Veiseh, assistant professor of bioengineering.
Once the correct dosage of "factories" to use was discovered, the results arrived. We have eliminated tumors in 100% of animals with ovarian cancer and seven out of eight with colorectal cancer.
What is the key factor of this solution?
Protective packaging plays a crucial role in drug factories, and not just in keeping their contents safe. This shell is built with materials that the body perceives as foreign, but only as a potential danger to be faced after a certain period of time. As a result, therapy does not continue indefinitely.
“We found that foreign body reactions effectively and safely blocked the release of cytokines from the capsules after 30 days,” says Veiseh. “Furthermore, we have shown that even a second cycle of therapy can be administered safely, if necessary.”
When they decided to build these tiny pharmaceutical laboratories, scientists took care to use only components already proven safe for human use. L'interleukin-2 is an FDA-approved anticancer therapy, and this new technology of delivering high doses directly to tumor sites creates a more robust immune response.
In this study, we demonstrated that 'drug factories' enable tunable local delivery of interleukin-2 and tumor eradication in different mouse models. This makes us excited about clinical trials.
Amir Jazaeri, co-author of the study
This technique, they say at Rice University, can be used against other malignant tumors: just set up the spheres of 'drug factories' with different types of cells to elicit various immunological responses.
