Boosting Natural Killer Cell Therapies in Glioblastoma Multiforme Using Supramolecular Cationic Inhibitors of Heat Shock Protein 90

Abstract

Allogeneic natural killer (aNK) cell adoptive therapy has the potential to dramatically impact clinical outcomes of glioblastoma multiforme (GBM). However, in order to exert therapeutic activity, NK cells require tumor expression of ligands for activating receptors, such as MHC Class I peptide A/B (MICA/B) and ULBPs. Here, we describe the use of a blood–brain barrier (BBB) permissive supramolecular cationic drug vehicle comprising an inhibitor of the chaperone heat shock protein 90 (Hsp90), which sustains a cytotoxic effect on GBM cells, boosts the expression of MICA/B and ULBPs on the residual population, and augments the activity of clinical-grade aNK cells (GTA002). First, we identify Hsp90 mRNA transcription and gain of function as significantly upregulated in GBM compared to other central nervous system tumors. Through a rational chemical design, we optimize a radicicol supramolecular prodrug containing cationic excipients, SCI-101, which displays >2-fold increase in relative BBB penetration compared to less cationic formulations in organoids, in vitro. Using 2D and 3D biological models, we confirm SCI-101 sustains GBM cytotoxicity 72 h after drug removal and induces cell surface MICA/B protein and ULBP mRNA up to 200% in residual tumor cells compared to the naked drug alone without augmenting the shedding of MICA/B, in vitro. Finally, we generate and test the sequential administration of SCI-101 with a clinical aNK cell therapy, GTA002, differentiated and expanded from healthy umbilical cord blood CD34+ hematopoietic stem cells. Using a longitudinal in vitro model, we demonstrate >350% relative cell killing is achieved in SCI-101–treated cell lines compared to vehicle controls. In summary, these data provide a first-of-its-kind BBB-penetrating, long-acting inhibitor of Hsp90 with monotherapy efficacy, which improves response to aNK cells and thus may rapidly alter the treatment paradigm for patients with GBM.

Targeting Heat Shock Proteins in Malignant Brain Tumors: From Basic Research to Clinical Trials

“…These results are the opposite of the study that employed a bioinformatics approach querying open repositories and pooling data from several clinical studies with over 1500 samples [ 98 ]. The study found mRNA expression of Hsp90 to be the highest in glioblastoma when compared to other tumor types, such as astrocytoma, and oligodendrogliomas, and the chaperon expression has the inverse correlation with disease-free survival ( Figure 8 ) [ 98 ]. The same association with survival was found by Sun et al, where HSP90B1 increased expression led to a shorter survival time [ 72 ].…”

“…** p < 0.01, **** p < 0.0001 analyzed by ordinary one-way ANOVA with Tukey’s multiple-comparison test. ( B ) Copy number alteration (CNA) evaluated across seven clinical studies (cBioPortal) [ 98 ].…”

Early TRAIL-engagement elicits potent multimodal targeting of melanoma by CD34+ progenitor cell-derived NK cells

“…Knowing that NK cytotoxicity is partially dependent on NKG2D for instance, could steer the development of combination therapies preventing shedding of its ligand MICA/B from tumor cells, 46 or boosting ligand expression using an inhibitor of heat shock protein 90. 47 Moreover, we observed that NKp46 seems to play an important role in NK activation. Therefore, combination with NK cell engagers that allow simultaneous targeting of NKp46 on NK cells and a target antigen on the tumor could be an interesting approach.…”

The chaperone system in glioblastoma multiforme and derived cell lines: diagnostic and mechanistic implications

“…In this study, we focused on molecular chaperones. These are the chief members of the CS and are known to play key roles in carcinogenesis, both anti-and pro-tumoral roles [11,14,29,[35][36][37][38][39]. They are also promising candidates as biomarkers for differential diagnosis, prognostication, and patient follow up.…”