Background MDSCs are a significant barrier to adoptive cell therapy (ACT) due to their suppressive effects on T-cells. We predict that there is an enrichment of MDSCs within bladder tumors and depletion of MDSCs may augment anti-tumor responses after intravesical ACT with tumor reactive T-cells. Methods For murine studies, orthotopic MB49-OVA bladder tumors were collected, stained for MDSCs, and analyzed by flow cytometry. Urine samples from bladder cancer patients were also collected and stained for MDSCs. From mice, purified MDSCs and OT-I T-cells were cocultured and from bladder cancer patients, purified urine MDSCs and CD3stimulated peripheral blood T-cells were cocultured to assess suppression of T-cell proliferation or IFN-gamma secretion. Mice bearing MB49-OVA tumors were treated with intravesical instillation of gemcitabine and/or OT-I T-cells and tumor growth was monitored via ultrasound. Results In mice bearing MB49-OVA tumors, the levels of polymorphonuclear (PMN)-MDSCs averaged between 11.1-23.5% of live cells and monocytic (M)-MDSCs averaged 7.6% of live cells, demonstrating that nearly 20-30% of live cells within murine bladder tumors are MDSCs. In the urine of bladder cancer patients, PMN-MDSCs predominantly make up the live cell population, averaging 71.7%, demonstrating an enrichment for MDSCs within the microenvironment of human bladder cancer. In murine coculture assays, MDSCs reduced the proliferation of OT-I T-cells and in human cocultures, MDSCs reduced T-cell IFN-gamma production to a fourth of control levels. Therefore, MDSCs from bladder tumors suppress anti-tumor T-cells by inhibiting proliferation and reactivity. In mice bearing large MB49-OVA tumors (>50mm3), pretreatment with gemcitabine improved anti-tumor response in combination with intravesical ACT with OT-I T cells in comparison to treatment with gemcitabine only (p=0.0387), OT-I only (p=0.0148), and untreated (p=.0039). In smaller MB49-OVA tumors (<50mm3), gemcitabine pretreatment provided little added benefit to ACT in comparison to treatment with gemcitabine only (p>0.05) and OT-I only (p>0.05). All p-values generated by performing Mann-Whitney tests on tumor volumes at final time points. Conclusions MDSCs make up a significant proportion of the immune population within bladder tumors and exert suppressive effects on T-cells. Our studies support the selective targeting of MDSCs via gemcitabine to improve the anti-tumor effects of ACT. While we show that a single instillation of gemcitabine and ACT improves anti-tumor responses, we predict that this effect will be further enhanced with multiple instillations of T-cells.
BACKGROUND: Improving the long-term efficacy for advanced renal cell carcinoma (RCC) remains challenging after progression on first line therapy. Adoptive cell therapy (ACT) using tumor infiltrating lymphocytes (TIL) is a promising personalized immunotherapeutic approach to treating solid tumors. Previously, TIL therapy for clear cell RCC patients showed moderate success but did not account for the distinct immune microenvironments in different subtypes of RCC such as clear cell (ccRCC), papillary (pRCC) or unclassified (uRCC) known to have different response to immunotherapy. In addition, hypoxia plays a critical role in tumor progression and therapy resistance in RCC. Therefore, the aim of this study was to evaluate TIL expansion from different subtypes of RCC under varying oxygen concentrations. METHODS: Tumor types collected from 48 patients included ccRCC (81.25%), pRCC (16.7%) and uRCC (8.3%). Tumors were minced into fragments and cultured for 4 weeks in media supplemented with high dose IL-2 (6000 IU/mL). At the end of the 4 weeks, TIL were further expanded using a rapid expansion protocol (REP) in either 20% or 5% oxygen. TIL expansion, reactivity to autologous tumor, and phenotype were evaluated in pre-REP and post-REP samples. RESULTS: Among the ccRCC, 91.7% of the samples expanded, while 100% of the pRCC and uRCC expanded. pRCC expanded more TIL than ccRCC (1.05e8 vs 6.7e7 total TIL expanded, respectively) while uRCC expanded less than the other subtypes (2.03e7). Pre-REP reactivity against autologous tumors was high for all the subtypes (88.3%, 75% and 100% for ccRCC, pRCC and uRCC respectively). The T-cell phenotype across subtypes showed a tendency of more CD4+ T-cells and less CD8+ T-cells for pRCC and uRCC, compared to ccRCC. All subtypes that underwent REP were able to expand in both 20% and 5% O2 (hypoxia) conditions. TIL expanded in hypoxia had a significantly higher percentage of tissue resident memory T-cells (CD69+CD103+; 15.1%, p<0.0001) when compared to the pre-REP TIL population (2%) or TIL expanded at 20% O2 (3.1%). CONCLUSION: These results demonstrate the feasibility of expanding tumor-reactive TIL from different subtypes of RCC for the first time, and highlight the advantage of exposing TIL to hypoxic conditions to enhance the differentiation of resident memory T-cells in TIL products. Citation Format: Marine Potez, Mohammed Alkhouli, Johannes Ali, Michael Carter, Matthew Beatty, Shari Pilon-Thomas, Jad Chahoud. Using hypoxia to improve tumor infiltrating lymphocytes therapy in different subtypes of renal cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference: Advances in Kidney Cancer Research; 2023 Jun 24-27; Austin, Texas. Philadelphia (PA): AACR; Cancer Res 2023;83(16 Suppl):Abstract nr B023.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.