Document resource
Background Adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TILs) represents a promising approach for advanced solid tumor treatment. This study aimed to assess the feasibility and efficacy of TIL expansion from clear cell renal cell carcinoma (ccRCC) to enhance TIL-based ACT. Given the significant role of hypoxia in ccRCC progression, we investigated TIL expansion under hypoxic conditions and its impact on TIL effector functions.Methods Fragments or tumor digests from 41 RCC patients were cultured with high-dose IL-2 for four weeks. Immune cells within the tumor microenvironment were assessed by flow cytometry. Expanded TIL phenotype and reactivity to autologous tumors were evaluated. Primary TIL underwent rapid expansion protocol (REP) at 20% or 5% O 2 levels. Reactivity to autologous tumor, expression of activation/co-inhibitory markers, and memory phenotype were analyzed.Results Despite exhausted CD8+ T-cells in the ccRCC microenvironment, TILs were successfully grown in 92.7% of samples. TILs secreted IFNγ in response to autologous tumors in 77.1% of the samples. Both TIL expansion and reactivity occurred independently of tumor stage or grade. TIL that underwent REP were able to expand in hypoxic conditions (5% O 2). Hypoxic TIL expanded in 5% O2 conditions, showed increased IFNγ, TNFα, and Granzyme B release compared to normoxic TIL. Notably, hypoxic TILs exhibited an elevated proportion of tissue-resident memory T-cells (CD69+CD103+).Conclusions This study demonstrates the feasibility of expanding tumor-reactive TILs from ccRCC despite exhausted CD8+ T-cells. Exposing TILs to hypoxic conditions improves their functionality and cytotoxic activity, suggesting an opportunity to overcome the current limited clinical efficacy of TIL-based ACT for ccRCC.