Novel Ab-(IL-12) Fusion Proteins for Breast Cancer Therapy
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Breast cancer patients whose tumors express high levels of a marker called “HER2/neu” have a particularly poor prognosis; this is the case in 25-30% of patients. Once this cancer has spread widely, the response to current therapies, such as the anti-HER2/neu antibody (Ab) trastuzumab, used alone or combined with other drugs, is limited. Thus, improved therapies are still urgently needed. 
 Our main goal is to develop new Ab fusion proteins, which are hybrid molecules composed of an Ab targeting HER2/neu that is bound to a modified (mutated) version of an immunostimulatory cytokine, intereukin-12 (IL12). In these new molecules, named “anti-HER2/neu IgG3-(mutIL-12) fusion proteins,” tumor targeting is provided by the Ab (“IgG3”) component, while the “IL-12” bound to the Ab is capable of increasing tumor killing by the Ab, and also can “teach” the patient’s immune system that these cancer cells are “foreign enemies” that should be destroyed. IL-12 has two natural binding activities, binding to its receptor (IL-12 receptor) on immune cells and also a more general binding pattern known as “heparin-binding activity” that allows it to bind to many types of cells and tissue structures. The central novelty of this project is the development of new versions of mutated IL-12 (mutIL-12) with impaired “heparin-binding activity” and thus a different binding pattern compared to that of the original, natural form of IL-12. This mutIL-12 is bound to anti-HER2/neu IgG3 Ab, resulting in a novel fusion protein whose properties we will define, when used against breast cancer. 
 The question(s) or central hypotheses of the research: We hypothesize that it is possible to develop antiHER2/neu Ab-(IL-12) fusion proteins containing mutated IL-12 (mutIL-12) with impaired heparin-binding activity and that these molecules will exhibit Ab and IL-12 functions. A central question is whether or not the new fusion proteins show differences in their levels in blood, binding patterns throughout the body, anti-tumor activity, and/or toxicity (side-effect) profile compared to the fusion protein containing the non-mutated (wildtype) IL-12. 
 The general methodology: We have already developed versions of the anti-HER2/neu IgG3-(mutIL-12) fusion proteins that exhibit impaired heparin-binding activity. We will explore the properties of the new fusion proteins in the test tube and in cell culture studies. These studies will include assessment of the interaction of these fusion proteins with immune cells and their ability to kill breast cancer cells grown in culture dishes. We will also study the toxicity, stability in blood, and the ability of the new fusion proteins to target and eliminate HER2/neu expressing tumors growing in mice, as well as the ability of these fusion proteins to awake the animal’s immune response against the tumor. 
 Innovative elements of the project: The main innovation of this project is the development of new versions of Ab-(IL-12) fusion proteins to develop better therapies for breast cancer. It is also important to understand the impact of the “heparin-binding activity” of IL-12 in general, to further our knowledge of the natural role of this activity and how it affects the function of IL-12. This cytokine has strong anti-tumor activity and can induce a potent immune response, but is limited by its toxicity to normal cells. Thus, it is important to understand how the loss of the “heparin-binding activity” affects the functions of this promising therapeutic molecule. Our proposal is innovative in terms of basic science and has also a translational (clinical) potential.