Development of GSK3 relocalizing peptides for cancer treatment - Development of GSK3 relocalizing peptides for cancer treatment The precise localization of proteins within distinct cellular compartments is essential for normal cellular function. Subcellular distribution dictates a protein’s interaction partners, post-translational modifications, and the signaling pathways it influences, meaning that any mislocalization can disrupt cellular homeostasis and alter regulatory pathways. Targeting protein mislocalization, either by preventing aberrant translocation or restoring proper compartment-specific function, holds significant therapeutic promise. In particular, small molecules, peptides, or genetic interventions that correct protein localization provide a novel approach for treating various diseases, including cancers, neurodegenerative disorders, and metabolic conditions. Our previous work revealed that mTORC1 signaling regulates cell growth and proliferation by controlling the translocation of GSK3. When GSK3 accumulates in the nucleus upon mTORC1 suppression, it suppresses major metabolic pathways and significantly reduces cancer cell proliferation. These findings suggest that strategies to direct GSK3 into the nucleus could yield potent anti-cancer effects. To explore this, I developed a platform technology called “protein relocalizing peptides” (R-peps), which redirect endogenous proteins to specific subcellular locations. Using this approach, I designed peptides that target GSK3 to the plasma membrane, peroxisomes, cytoplasm, and nucleus. Consistent with nuclear GSK3’s observed anti-cancer properties, our nuclear-targeting RNLS-pep significantly suppressed proliferation in multiple cancer cell lines. Our primary objective is to assess the anti-cancer efficacy of GSK3 RNLS-pep both as a standalone therapy and in combination with the chemotherapeutic agent 5-FU. To achieve this, we will employ multiple orthotopic mouse models of lung, brain, and colorectal cancers, delivering RNLS-pep via an AAV system designed to efficiently target tumor cells in vivo. We will evaluate tumor progression, survival outcomes, and molecular indicators of GSK3 activity to determine whether RNLS-pep synergizes with 5-FU while exerts robust therapeutic effects on its own. Animal models are essential for evaluating the in vivo therapeutic efficacy, tissue-specific delivery, and safety of GSK3 RNLS-pep within the complex tumor microenvironment and metastatic setting that cannot be fully recapitulated in vitro. Ultimately, this project will provide a thorough preclinical evaluation of GSK3 RNLS-pep, either as a standalone therapy or in combination with existing chemotherapy regimens. Demonstrating the feasibility and potency of this approach will illustrate how precise manipulation of protein localization can be harnessed to combat cancer. These findings may lay the groundwork for broader applications of protein relocalizing peptides (R-peps) in other diseases where subcellular mislocalization underlies pathological processes.
