Safran, H. P. | Search bioRxiv

bioRxiv2024

Combination of Imipridone ONC201 or ONC206 with Temozolomide and Radiotherapy in triple ITR therapy reduces intracranial tumor burden and prolongs survival in an orthotopic wild-type IDH GBM mouse model

Glioblastoma remains the most lethal common primary brain tumor in adults with limited therapeutic options. TIC10/ONC201, a first-in-class imipridone we discovered, achieved meaningful therapeutic effects in phase I/II trials in patients with diffuse gliomas harboring H3K27M mutations, and currently the drug is in randomized phase III testing (ACTION trial; NCT05580562). ONC201 targets mitochondrial protease ClpP to disrupt oxidative phosphorylation and trigger the integrated stress response (ISR), TRAIL/DR5, and tumor cell death. We hypothesized that ONC201 and its analogue ONC206 synergize with temozolomide (TMZ) and ionizing radiation (IR), standard-of-care glioblastoma therapies. ONC201 enhances TMZ or IR-induced apoptosis, and cytotoxicity. ClpP-silencing suppresses ONC201-induced cytotoxicity but not TMZ or RT. Both ONC201 and ONC206 reduce expression of TMZ-resistance mediator MGMT. Suppression of MGMT protein was observed in H3K27M-mutated DIPG cell lines following treatment with ONC201 or ONC206 with or without TMZ. Cytokine profiling indicates distinct ONC201 alterations relative to TMZ suggesting distinct anti-tumor immune mechanisms. Triple IR+TMZ+ONC201 (ITR) therapy prolongs median survival to 123 days with a tail on survival curve (3-of-7 mice alive beyond 200-days) in an orthotopic U251 GBM model versus ONC201 (44-days; p=0.000197), IR (63-days; p=0.0012), TMZ (78-days; p=0.0354), ONC201+IR (55-days; p=0.0004), ONC201+TMZ (80-days; p=0.0041) and IR+TMZ (103-days; p>0.05). By 231-days, the only surviving mice were in IRT group. Our results support investigation of ONC201/ONC206 in combination with TMZ and IR (ITR) in GBM or H3K27M mutated diffuse glioma therapy.

cancer biology↗

bioRxiv2023

Androgen receptor signaling blockade enhances NK cell-mediated killing of prostate cancer cells and sensitivity to NK cell checkpoint blockade

BackgroundThe blockade of the androgen receptor (AR) pathway is an effective treatment for prostate cancer (PCa), but many patients progress to metastatic castration-resistant prostate cancer (mCRPC). Treatments for mCRPC include AR inhibitors (ARi), chemotherapy, PARP inhibitors, and radioligands. Checkpoint inhibitor activity is limited to a small subset of MSI-H mCRPC. AR signaling modulates CD8+ T cell function, but its impact on natural killer (NK) cell cytotoxicity is unknown. We investigated the effect of ARi on NK cell activation, cytokine secretion, NKG2A expression, and NK cell-mediated killing of PCa cells in vitro. MethodsPCa cell lines (LNCaP, 22Rv1, DU145, PC3) were co-cultured with NK-92 and treated with ARi (enzalutamide [enza], darolutamide [daro]) alone or in combination with anti-NKG2A antibody monalizumab. Immune cell-mediated tumor cell killing and cytokine secretion were quantified. NK cell expression of NKG2A and PCa cell expression of HLA-E were investigated by flow cytometry. The AR-negative cell lines PC3 and DU145 were stably transduced with an AR expression vector to evaluate the AR modulation of HLA-E. To assess the in vivo combination of NKG2A blockade and ARi therapy in vivo, Cas9 was used to genetically ablate the murine HLA-E ortholog, H2-T23, from RM-1 murine PCa cells. H2-T23 knockout and control cells were grown subcutaneously in castrated C57BL/6 mice and treated with daro or control. The activation status of peripheral blood NK cell isolated from patients with PCa before and after initiation of androgen deprivation therapy (ADT) was evaluated by flow cytometry. ResultsARi activated NK cells and significantly increased immune-mediated NK-92 cell killing of PCa cells. IFN-{gamma} and TRAIL mediated ARi-induced NK cell activation. ARi increased expression of the inhibitory receptor NKG2A on NK cells, and immune killing of PCa cells was enhanced with the combination of ARi and monalizumab. ARi also increased the expression of HLA-E, the ligand of NKG2A, on PCa cell lines. By transducing AR into AR-negative PC3 and DU145, we demonstrated that androgen signaling regulates HLA-E expression. In a mouse model of PCa, HLA-E knockout synergized with darolutamide to increase NK cell activation. NK cells derived from patients with metastatic PCa exhibited increased expression of Granzyme B and Perforin following ARi treatment. ConclusionsARi activates NK cells via IFN-{gamma} and TRAIL and promotes the killing of PCa cells. ARi also upregulates expression of HLA-E on PCa which may suppress the innate immune response against PCa. ARi-mediated NK cell killing of PCa cells was enhanced by NKG2A blockade. These results support novel immunotherapeutic strategies for PCa targeting NK activation through the combination of ARi and monalizumab. Graphical AbstractAndrogen receptor inhibitors (ARi) enhance NK cell-mediated killing of prostate cancer cells and sensitivity to NK cell checkpoint NKG2A blockade. ARi upregulate the NK cell inhibitor ligand (HLA-E) mediating suppression NK cell killing of PCa. This regulation is dependent on a functional AR signal on tumor cell lines. Adding an anti-NKG2a-HLA-E mAb with ARi further enhances the NK cell-mediated killing of PCa. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/567201v2_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@ba35e6org.highwire.dtl.DTLVardef@128a2e7org.highwire.dtl.DTLVardef@def16aorg.highwire.dtl.DTLVardef@bb72e7_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗