Cancer immunotherapy has revolutionized the treatment landscape for several malignancies by harnessing the patient’s own immune system to identify and eradicate tumor cells. Yet, despite significant successes in cancers such as melanoma and lung cancer, ovarian cancer poses a unique challenge. Its tumor microenvironment is notably immunosuppressive, limiting the efficacy of conventional immunotherapies like checkpoint inhibitors. Researchers at MIT have now taken a stride toward overcoming this barrier by engineering innovative nanoparticles that deliver the cytokine interleukin-12 (IL-12) directly to ovarian tumors, promising a new paradigm in treating this deadly disease.
Checkpoint inhibitors have transformed oncology by blocking immune checkpoint pathways, effectively releasing the brakes on T cells to attack tumors. However, these biologics alone often fail against ovarian cancer due to its complex and suppressive microenvironment, which actively hinders the activation and infiltration of effector immune cells. The “brakes” can be removed, but no “gas pedal” exists to stimulate robust immune activation. The MIT team’s approach centers on providing that vital acceleration through IL-12, a potent cytokine known to enhance the function and proliferation of T cells and natural killer cells, thus invigorating tumor-specific immunity.
Delivering IL-12 systemically has been fraught with challenges. High doses necessary to elicit therapeutic effects cause serious side effects, including systemic inflammation, flu-like symptoms, liver toxicity, and even life-threatening cytokine release syndrome. Conventional administration methods result in widespread cytokine exposure, jeopardizing patient safety. Addressing this, the MIT researchers designed specialized nanoparticles capable of transporting IL-12 with precision directly to tumor sites, minimizing systemic toxicity and enabling the safe use of higher effective doses.
The core of these nanoparticles is composed of liposomes—spherical vesicles made of lipid bilayers—that serve as carriers for IL-12 molecules tethered on their surfaces. This design ensures the cytokine is presented in close proximity to tumor cells, facilitating direct engagement with immune cells within the tumor microenvironment. A significant innovation in this new generation of particles is the chemical linker maleimide used to hold IL-12 on the liposome surfaces. This linker provides enhanced stability, preventing premature release and allowing sustained delivery of IL-12 over roughly one week, thereby maintaining continuous immune stimulation.
To achieve targeted delivery, the nanoparticles are coated with poly-L-glutamate (PLE), a polymer that homes particles selectively to ovarian tumor cells. Upon reaching the tumor site within the peritoneal cavity, which contains not only the ovaries but also surfaces of key organs including intestines, liver, and pancreas, these liposome-IL-12 complexes latch onto cancer cell membranes. Their gradual release of IL-12 transforms the immunosuppressive niche by recruiting and activating T cells capable of penetrating tumors and executing cytotoxic functions.
Preclinical studies using mouse models bearing metastatic ovarian cancer revealed striking outcomes. When administered as a monotherapy, the IL-12 nanoparticles induced tumor eradication in approximately 30 percent of treated animals, a promising outcome demonstrating the capacity of IL-12 delivery to reprogram immune activity. Critically, when combined with checkpoint inhibitors, which remove inhibitory signals on T cells, the therapeutic efficacy soared: over 80 percent of mice experienced complete remission of tumors, even in models highly resistant to standard chemotherapy and immunotherapy agents.
Further demonstrating the power of this approach, the investigators conducted tumor rechallenge experiments to simulate cancer recurrence. Mice cured with the nanoparticle and checkpoint inhibitor treatment displayed durable immune memory, as evidenced by their ability to rapidly identify and eliminate newly introduced tumor cells months after initial therapy. This long-lasting immune vigilance could translate into clinical prevention of ovarian cancer relapse, a notorious obstacle limiting patient survival.
The engineering sophistication extends beyond biological efficacy to practical considerations. A parallel study by the same group introduced scalable manufacturing methods for these nanotherapeutics, addressing a critical bottleneck for clinical translation. This new chemistry and production pipeline pave the way for larger, more affordable batches of IL-12 nanoparticles, essential for progressing toward human trials and eventual commercialization.
Behind this breakthrough are leading scientists Paula Hammond and Darrell Irvine, whose collaborative research integrates expertise in immunology, materials science, and nanotechnology. Their multidisciplinary approach leverages advanced chemistry to solve biological challenges in cancer treatment, embodying the convergence of engineering and medicine. The work also highlights how precise control over nanoparticle surface chemistry and payload release kinetics is vital to overcoming longstanding limitations in cytokine therapy.
Ovarian cancer remains a formidable clinical adversary with a high mortality rate largely due to late diagnosis and resistance to current therapies. Novel immunotherapeutic strategies like the IL-12 nanoparticle platform offer hope for more effective, targeted treatments that not only eradicate tumors but also establish lasting immunity against recurrence. This dual mode of action could revolutionize care for patients with advanced disease typically refractory to existing immunotherapy.
As the research advances towards human application, efforts are underway to partner with industry to facilitate clinical development and regulatory approval. Success in this endeavor could see IL-12-releasing nanoparticles becoming an integral component of ovarian cancer treatment regimens, either complementing surgery and chemotherapy or serving as standalone immunotherapies. The implications extend beyond ovarian cancer as well, with the nanoparticle platform adaptable to deliver other immune modulators for a variety of tumor types.
This promising study, just published in Nature Materials, underscores the critical role of nanotechnology in transforming cancer immunotherapy by enhancing delivery precision and controlling drug release kinetics. By effectively “hitting the gas” on the immune system in a spatially confined manner, these IL-12 nanoparticles overcome major hurdles that have restrained effective treatment of immune-evasive tumors. The future of cancer therapy increasingly lies in such engineered convergence of immunology and materials science, heralding a new era of smarter, more potent cancer immunotherapies.
Subject of Research: Animals
Article Title: IL-12-releasing nanoparticles for effective immunotherapy of metastatic ovarian cancer
News Publication Date: 31-Oct-2025
Web References: http://dx.doi.org/10.1038/s41563-025-02390-9
Keywords: Cancer, Ovarian cancer, Nanoparticles, Nanomaterials, Cytokines, Immunotherapy, Nanotechnology, Materials science, Tumor microenvironment, T cells, Liposomes, IL-12
