Cancer researchers at Rice University recently conducted a study on how a novel method of anti-cancer medication administration would affect tumors in mice. This exciting new study showed that the potential new treatment method effectively eradicated tumors in a sample of mice within six days. The authors of the study are optimistic that this groundbreaking cancer drug delivery system could show similar effectiveness in human patients. The Rice University team plans to hold clinical trials with human participants later this year.
The Role of Cytokines in Fighting Tumors
Cytokines are small proteins that act as messengers in the immune system. These proteins stimulate white blood cell responses designed to fight against diseases. Cytokines are also responsible for controlling the growth and activity of other cells in the immune system and also blood cells.
Prior studies have investigated how external cytokines can be used to trigger the activation of the immune system. Several proinflammatory cytokines have shown promising results as tumor-fighting agents, but the bulk of the research has been dedicated to a cytokine called interleukin-2 (IL2) because of its role in the body’s regulation of immune cells, including T-cells.
IL2 treatments have been in use for 30 years under brand names like Aldesleukin and Proleukin, but these treatments have stumbling blocks that limit their effectiveness. Because the half-life of IL2 in the bloodstream is extremely short, these established IL2 treatments must be administered in high-dose infusions in order to significantly reduce tumors.
Additionally, many patients experience off-target effects and toxicities, along with side effects like tissue damage and vascular leak syndrome. These severe side effects require many patients to stop receiving the infusions. As a result, cytokines have not been widely adopted in the oncology field.
Designing a ‘Drug Factory’ for Delivering IL2
Led by Rice University bioengineers Amanda Nash and Omid Veiseh, the team of researchers developed a “drug factory” designed to safely provide continuous high doses of IL2 directly to the tumor. To test the system’s effectiveness, the scientists used minimally invasive surgery to implant the drug factories, each about the size of a pinhead, into both rodent and nonhuman-primate subjects. Each “drug factory” was encased in a protective shell containing cells that were engineered to produce IL2. The protective shell allowed the interior factory to produce cytokine without the danger of suffering attacks from the immune system.
Methodology of the Rice University Cytokine Study
The researchers sought to test the effectiveness of this novel treatment against two specific types of cancer: ovarian and colorectal. Thus, their first step was to genetically modify the abdominal cavities of the animals to produce these cancers. IL2 was then directly administered into each animal’s peritoneum – a membrane that holds the intestines, ovaries, and abdominal organs.
The final step was to harvest tissue samples from the liver, kidney, and spleen of each animal and then to measure the tumor-reducing ability of the drug factory in the rodents, along with evaluating the toxicity levels found in the nonhuman-primates. The test results were then compared with the results of a control group.
Findings of This Study
The IL2 delivery system proved to be effective in tumor reduction for both colorectal and ovarian cancers. According to the scientist’s findings, the treatment group showed significant tumor reduction within six days. By the 15th day following the experiment, the ovarian cancer treatment group exhibited at least a 90% reduction in tumor size. Additionally, four out of the five mice with colorectal cancer were tumor-free by day 15.
At the end of the observation period, the team of scientists recorded that 100% of the ovarian cancer tumors were eradicated, while seven out of the eight animals with colorectal cancer were tumor-free.
The nonhuman-primate group was tested for potential safety and toxicity issues. The results from this section of the study were also encouraging, as the study authors wrote that the delivery system was “well-tolerated” in the animals. Based on these findings, the researchers concluded that this IL2 delivery system could be used as a cancer immunotherapy treatment without systemic toxicities.
The Next Steps
This study is just one of the latest in the growing field of research into cancer immunotherapy treatments. A great deal of recent research has specifically focused on addressing the debilitating issues that are present in many modern immunotherapies, including drug resistance and severe side effects.
The study’s authors are optimistic that their findings could eventually lead to the development of an IL2 delivery system that addresses the common issues associated with modern IL2 treatments. However, their optimism is cautious, as the system still needs to be tested on human volunteers in clinical trials. Sometimes, treatment methods that are effective in animal samples do not yield similar results during human clinical trials.
Because IL2 has already been approved for safe use in humans, the Rice University scientists are hopeful that they will receive fast approval for clinical trials later this year.