Small-molecule Inhibition of Glycogen Synthase Kinase-3 Sensitizes Colorectal Cancer Cells and Stimulates Immune Cells to Bolster Immune Cell-mediated Tumor Cytotoxicity - PROJECT SUMMARY
Globally, colorectal cancer (CRC) ranks third in incidence and second in mortality. Immune checkpoint blockade
(ICB) has demonstrated impressive efficacy in microsatellite instability (MSI)-positive CRC, however, there
remains a substantial unmet need for 96% of patients with microsatellite stable (MSS) advanced CRC who don’t
respond. A growing literature supports an immunomodulatory role of glycogen synthase kinase-3 (GSK-3) in the
context of anti-tumor immunity. The proposed research focuses on GSK-3 inhibitor 9-ING-41. We hypothesize
that GSK-3 inhibition can improve efficacy of ICB by (1) activating immune cells via increased
inflammatory mediators and decreased checkpoint receptor expression and by (2) sensitizing tumor
cells to immune cell-mediated tumor cell killing via increased death receptor expression and signaling,
increased checkpoint ligand expression, and decreased survival pathway signaling. In year one, Aim 1
experiments will examine the potential of 9-ING-41 to promote anti-tumor immunity, modify NF-κB signaling, and
regulate immune checkpoint expression in vitro. In our preliminary evaluation of 9-ING-41 in a co-culture assay
we observed increased immune cell-mediated tumor cell killing with 9-ING-41, compared to control. We will
analyze cytokine profiles of tumor and immune cells treated with 9-ING-41 to make predictions about therapeutic
impact on anti-tumor immunity. We plan to evaluate checkpoint ligand expression and downstream targets of
NF-κB signaling using western blots, RNA-seq, and flow cytometry in 9-ING-41-treated cells. In year two, Aim 2
experiments will utilize an immunocompetent, syngeneic murine CRC model to monitor immune cell invasion
and activation, and tumor cell killing in response to 9-ING-41 monotherapy or combination ICB therapy with αPD-
1 or αPD-L1. This work will be carried out in Dr. Wafik El-Deiry’s lab, which has expertise in CRC, cytokine
profiling, in vivo experimental design, biomarkers, and clinical translation. Because the El-Deiry Lab is located
at Brown University, we have access to state-of-the-art bioimaging, genomics, microscopy, and flow cytometry
facilities. The Cancer Center at Brown, located within the same building as the lab, offers the applicant access
to invited speaker seminars, research program meetings, and translational research disease group meetings,
while the Pathobiology Program offers invited speaker seminars and journal clubs. This environment enables
the training plan by facilitating the applicant’s new technical skills, cancer biology and immunology expertise,
and through individualized mentorship, teaching, and scientific communication opportunities. The project will
lead to the applicant’s mastery of new technical and research design skills in addition to career development
included within the fellowship training plan. This novel research will offer mechanistic insights into the
immunomodulatory mechanisms of GSK-3 inhibitors and will address the significant unmet need of effective
immunotherapy combinations for the vast majority of patients with CRC who don’t respond to ICB therapy.
