Biology subjects

Purcell, C.

Publications and source records attributed to Purcell, C..

5 recordsLinked to original sources

bioRxiv2024

Neuroendocrine differentiation (ND) in sensitivity of neuroendocrine tumor (NET) cells to ONC201/TIC10 cancer therapeutic

Prostate cancer (PCa) neuroendocrine tumor (NET)-like cells with low or absent androgen receptor (AR) signaling cause hormone therapy resistance and poor prognosis. Small cell lung carcinoma (SCLC), a high-grade NET, presents with metastasis early and has poor survival. ONC201/TIC10 is a first-in-class cancer therapeutic with clinical activity in diffuse gliomas and neuroendocrine tumors. We hypothesized that markers of neuroendocrine differentiation, activation of the integrated stress response (ISR) and the TRAIL pathway, as well as the expression of ClpP, contribute to neuroendocrine tumor cell death and sensitivity to ONC201. We show that PCa and SCLC cell lines (N=6) are sensitive to ONC201, regardless of the extent of neuroendocrine differentiation. Endogenous levels of some NET markers (CgA, FoxO1, ENO2, PGP9.5, SOX2) are present in a spectrum in PCa and SCLC cell lines. Overexpression of neural transcription factor BRN2 in DU145 PCa cells does not increase expression of NET differentiation markers FoxO1, ENO2, PGP9.5, and CgA at 48 hours. However, the transient BRN2 overexpression showed slight decreases in some NET markers on the spectrum while maintaining sensitivity of PCa cells to ONC201 before any phenotypic change related to NET differentiation. Our results show that ONC201 has preclinical activity against PCa including those without NET markers or in PCa cells with transient overexpression of neural transcription factor BRN2. Our results have relevance to activity of ONC201 in PCa where most castrate-resistant androgen-independent cancers are not therapy resistant due to NET differentiation. Importantly, NET differentiation does not promote resistance to ONC201 supporting further clinical investigations across the spectrum of PCa.

cancer biology↗

bioRxiv2024

Neuroendocrine Prostate Cancer Drivers SOX2 and BRN2 Confer Differential Responses to Imipridones ONC201, ONC206, and ONC212 in Prostate Cancer Cell Lines

Prostate cancer (PCa) is the leading cause death from cancer in men worldwide. Approximately 30% of castrate-resistant PCas become refractory to therapy due to neuroendocrine differentiation (NED) that is present in <1% of androgen-sensitive tumors. First-in-class imipridone ONC201/TIC10 has shown clinical activity against midline gliomas, neuroendocrine tumors and PCa. We explored the question of whether NED promotes sensitivity to imipridones ONC201 and ONC206 by inducible overexpression of SOX2 and BRN2, well-known neuroendocrine drivers, in human PCa cell lines DU145 or LNCaP. Slight protection from ONC201 or ONC206 with SOX2 and BRN2 overexpression was observed in the inducible LNCaP cells but not in the DU145 cells. At 2 months, there was an apparent increase in CLpP expression in LNCaP SOX2-overexpressing cells but this did not confer enhanced sensitivity to ONC201. DU145 SOX2-overexpressing cells had a significantly reduced ONC201 sensitivity than DU145 control cells. The results support the idea that treatment of castrate-resistant prostate cancer by imipridones may not be significantly impacted by neuroendocrine differentiation as a therapy-resistance mechanism. The results support further testing of imipridones across subtypes of androgen-sensitive and castrate-resistant prostate cancer.

cancer biology↗

bioRxiv2024

AAnet resolves a continuum of spatially-localized cell states to unveil tumor complexity

Identifying functionally important cell states and structure within a heterogeneous tumor remains a significant biological and computational challenge. Moreover, current clustering or trajectory-based computational models are ill-equipped to address the notion that cancer cells reside along a phenotypic continuum. To address this, we present Archetypal Analysis network (AAnet), a neural network that learns key archetypal cell states within a phenotypic continuum of cell states in single-cell data. Applied to single-cell RNA sequencing data from pre-clinical models and a cohort of 34 clinical breast cancers, AAnet identifies archetypes that resolve distinct biological cell states and processes, including cell proliferation, hypoxia, metabolism and immune interactions. Notably, archetypes identified in primary tumors are recapitulated in matched liver, lung and lymph node metastases, demonstrating that a significant component of intratumoral heterogeneity is driven by cell intrinsic properties. Using spatial transcriptomics as orthogonal validation, AAnet-derived archetypes show discrete spatial organization within tumors, supporting their distinct archetypal biology. We further reveal that ligand:receptor cross-talk between cancer and adjacent stromal cells contributes to intra-archetypal biological mimicry. Finally, we use AAnet archetype identifiers to validate GLUT3 as a critical mediator of a hypoxic cell archetype harboring a cancer stem cell population, which we validate in human triple-negative breast cancer specimens. AAnet is a powerful tool to reveal functional cell states within complex samples from multimodal single-cell data.

bioinformatics↗

bioRxiv2024

ITGB6 inhibition stimulates anti-tumor responses in immunocompetent mouse models of head & neck squamous cell carcinoma and pancreatic adenocarcinoma

ITGB6, the gene encoding the {beta}6 subunit of integrin v{beta}6, is a potent prognostic marker across multiple cancer types. As a major activator of latent TGF{beta}, v{beta}6, and consequently, ITGB6, has considerable therapeutic implications due to the immunosuppressive effect that activated TGF{beta} has on the tumor microenvironment. The present study identifies ITGB6 as a potent target for inducing an immune-mediated anti-tumor response. ITGB6 is highly upregulated in various squamous cell carcinomas and pancreatic adenocarcinomas, allowing it to disrupt tumor-immune cell signaling, while avoiding the widespread side-effects of systemic TGF{beta} inhibition. Genetic knockout of ITGB6 in heterotopically injected head and neck squamous cell carcinoma and pancreatic adenocarcinoma cell lines showed markedly reduced tumor progression in immunocompetent mice. Additionally, co-cultures of human squamous cell carcinoma cell lines and human T-cells showed increased T-cell killing upon cancer cell ITGB6 inhibition. Colony formation experiments give further evidence that the reduction in tumor growth observed upon ITGB6 inhibition in vivo is through immunological clearance of cancer cells and not merely through intrinsic factors. Analysis of The Cancer Genome Atlas (TCGA) revealed not only the high prognostic value of ITGB6 on overall survival but also that high ITGB6 expression in patients is often associated with an inferior response to -PD-1 and -PD-L1 immune checkpoint blockade. The potent anti-tumor immune response observed both in vitro and in vivo upon ITGB6 inhibition, combined with our analysis of RNA-seq data from immune checkpoint blockade-treated patients, encourages the development of ITGB6 blockade and immunotherapy combination regimes. Further pre-clinical studies will serve to facilitate the translation of our findings into therapeutic clinical trials of combination therapies for treating immunotherapy-resistant cancers. Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/590156v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@162546aorg.highwire.dtl.DTLVardef@9422d6org.highwire.dtl.DTLVardef@17b4a5eorg.highwire.dtl.DTLVardef@14f903d_HPS_FORMAT_FIGEXP M_FIG C_FIG

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↗