Targeted hypoxia reduction restores T cell infiltration and sensitizes prostate cancer to immunotherapy
Priyamvada Jayaprakash, … , Tomasz Zal, Michael A. Curran
Priyamvada Jayaprakash, … , Tomasz Zal, Michael A. Curran
Published September 6, 2018
Citation Information: J Clin Invest. 2018;128(11):5137-5149. https://doi.org/10.1172/JCI96268.
View: Text | PDF
Research Article Immunology Oncology

Targeted hypoxia reduction restores T cell infiltration and sensitizes prostate cancer to immunotherapy

Abstract

Despite the success of immune checkpoint blockade against melanoma, many “cold” tumors like prostate cancer remain unresponsive. We found that hypoxic zones were prevalent across preclinical prostate cancer and resisted T cell infiltration even in the context of CTLA-4 and PD-1 blockade. We demonstrated that the hypoxia-activated prodrug TH-302 reduces or eliminates hypoxia in these tumors. Combination therapy with this hypoxia-prodrug and checkpoint blockade cooperated to cure more than 80% of tumors in the transgenic adenocarcinoma of the mouse prostate–derived (TRAMP-derived) TRAMP-C2 model. Immunofluorescence imaging showed that TH-302 drives an influx of T cells into hypoxic zones, which were expanded by checkpoint blockade. Further, combination therapy reduced myeloid-derived suppressor cell density by more than 50%, and durably reduced the capacity of the tumor to replenish the granulocytic subset. Spontaneous prostate tumors in TRAMP transgenic mice, which completely resist checkpoint blockade, showed minimal adenocarcinoma tumor burden at 36 weeks of age and no evidence of neuroendocrine tumors with combination therapy. Survival of Pb-Cre4, Ptenpc–/–Smad4pc–/– mice with aggressive prostate adenocarcinoma was also significantly extended by this combination of hypoxia-prodrug and checkpoint blockade. Hypoxia disruption and T cell checkpoint blockade may sensitize some of the most therapeutically resistant cancers to immunotherapy.

Authors

Priyamvada Jayaprakash, Midan Ai, Arthur Liu, Pratha Budhani, Todd Bartkowiak, Jie Sheng, Casey Ager, Courtney Nicholas, Ashvin R. Jaiswal, Yanqiu Sun, Krishna Shah, Sadhana Balasubramanyam, Nan Li, Guocan Wang, Jing Ning, Anna Zal, Tomasz Zal, Michael A. Curran

×

Figure 4

Combined hypoxia ablation and checkpoint blockade decreases MDSC suppressive capacity and promotes T cell effector function.

Options: View larger image (or click on image) Download as PowerPoint
Combined hypoxia ablation and checkpoint blockade decreases MDSC suppres...
(A) Mice were implanted with TRAMP-C2 tumors in 30% Matrigel and treated beginning on day 21 for 1 cycle. Two days later, mice were injected with pimonidazole and euthanized 6 hours later. Proliferation of tumor-infiltrating Gr-MDSCs (CD11b+Ly6G+Ly6C–) in pimonidazole-negative (normoxia) and pimonidazole-positive (hypoxia) regions was assessed by Ki67 staining (6–7 mice per group, n = 1). (B) Mice were treated as in A but for 2 cycles of therapy. Two days later, tumor-infiltrating CD11b+Gr-1+ MDSCs were sorted and cocultured with αCD3/αCD28–activated T cells for 72 hours. T cell proliferation was assessed by CFSE dilution. Tumors from 14–16 mice with bilateral tumors were pooled for each condition. (C and D) Mice were treated as in B but starting at day 14. The next day, tumor-infiltrating lymphocytes were purified and analyzed by flow cytometry for Ki67 (proliferation) expression (C) and granzyme B (cytotoxic potential) expression (D) (n = 5). Teff, effector T. (E) Mice were treated as in A, and apoptosis of tumor-infiltrating TCRβ+CD8+ T cells in pimonidazole-negative (normoxia) and pimonidazole-positive (hypoxia) regions was assessed by active caspase-3 staining (6–7 mice per group, n = 1). (F and G) Mice were treated as in A. The next day, tumor-infiltrating TCRβ+CD8+ T cells were isolated and activated for 5 hours using Leukocyte Activation Cocktail with Golgi Plug and assessed for expression of CD44 (F) and IFN-γ and TNF-α (G) in the 4-1BBmed/hi subset of CD8+ T cells (10 mice per group, n = 1). Statistical significance between groups was determined by Student’s t test for A and E–G, and by ANOVA for B–D. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. MFI, mean fluorescence intensity.