S-15 in combination of Akt inhibitor promotes the expansion of CD45RA-CCR7+ tumor infiltrating lymphocytes with high cytotoxic potential and downregulating PD-1+Tim-3+ cells as well as regulatory T cells

Benling Xu; Long Yuan; Guangyu Chen; Tiepeng Li; Jinxue Zhou; Chengjuan Zhang; Peng Qin; Musleh M Muthana; Shengdian Wang; Xuexiang Du; Quanli Gao

doi:10.1186/s12935-019-1043-3

S-15 in combination of Akt inhibitor promotes the expansion of CD45RA^-CCR7⁺ tumor infiltrating lymphocytes with high cytotoxic potential and downregulating PD-1⁺Tim-3⁺ cells as well as regulatory T cells

Cancer Cell Int. 2019 Dec 3:19:322. doi: 10.1186/s12935-019-1043-3. eCollection 2019.

Authors

Benling Xu^#¹, Long Yuan^#², Guangyu Chen¹, Tiepeng Li¹, Jinxue Zhou³, Chengjuan Zhang¹, Peng Qin¹, Musleh M Muthana⁴, Shengdian Wang⁵, Xuexiang Du¹, Quanli Gao¹

Affiliations

¹ 1Department of Immunotherapy, The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan People's Republic of China.
² 2Department of General Surgery, The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan People's Republic of China.
³ 3Department of Hepatobiliary and Pancreatic Surgery, The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan People's Republic of China.
⁴ 4Division of Immunotherapy, Institute of Human Virology, University of Maryland, Baltimore, MD 21201 USA.
⁵ 5CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.

^# Contributed equally.

Abstract

Background: Autologous tumor-infiltrating lymphocytes (Tils) immunotherapy is a promising treatment in patients with advanced hepatocellular cancer. Although Tils treatment has shown great promise, their persistence and the efficacy after adoptive-transfer are insufficient and remain a challenge. Studies have demonstrated that IL-15 and Akt inhibitor can regulate T cell differentiation and memory. Here, we constructed S-15 (Super human IL-15), a fusion protein consisting of human IL-15, the sushi domain of the IL-15 receptor α chain and human IgG-Fc. Herein we compared the effects of S-15 with IL-2 or in combination with Akti on the expansion and activation of Tils.

Methods: Hepatocellular cancer tissues were obtained from 6 patients, Tils were expanded using IL-2, IL-2/S-15, IL-2/Akti or in combination IL-2/S-15/Akti. At day 10, anti-CD3 antibody was added to the culture media and expanded to day 25. The composition, exhaustion and T-cell differentiation markers (CD45RA/CCR7) were analyzed by flow cytometry.

Results: We found that IL-2/S-15/Akti expanded Tils and showed the highest percentage of central memory CD45RA^-CCR7⁺ phenotype prior to anti-CD3 antibody activation and after anti-CD3 antibody activation. T cells cultured with IL-2/S-15/Akti exhibited a mixture of CD4⁺, CD8⁺, and CD3⁺CD4^-CD8^- T cells; S-15 in combination with Akt inhibitor downregulated the expression of PD-1⁺Tim-3⁺ on Tils and decreased the Tregs in Tils. Additionally, the Tils expanded in the presence of the Akt inhibitor and S-15 showed enhanced antitumor activity as indicated by the increase in IFN-γ producing tumor infiltrating CD8⁺ T cells and without comprising the Tils expansion.

Conclusion: Our study elucidates that IL-2/S-15/Akti expanded Tils and represent a viable source for the cellular therapy for patients with hepatocellular cancer.

Keywords: Akt inhibitor; Central memory T cells; Hepatocellular cancer; Programmed death 1; Regulatory T-cells; Tumor infiltrating T lymphocytes.