Alpha-Fetoprotein- and CD40Ligand-Expressing Dendritic Cells for Immunotherapy of Hepatocellular Carcinoma

Abstract

Dendritic cells (DC) as professional antigen presenting cells are able to prime T-cells against the tumor-associated antigen α-fetoprotein (AFP) for immunotherapy of hepatocellular carcinoma (HCC). However, a strong immunosuppressive tumor environment limits their efficacy in patients. The co-stimulation with CD40Ligand (CD40L) is critical in the maturation of DC and T-cell priming. In this study, the impact of intratumoral (i.t.) CD40L-expressing DC to improve vaccination with murine (m)AFP-transduced DC (Ad-mAFP-DC) was analyzed in subcutaneous (s.c.) and orthotopic murine HCC. Murine DC were adenovirally transduced with Ad-mAFP or Ad-CD40L. Hepa129-mAFP-cells were injected into the right flank or the liver of C3H-mice to induce subcutaneous (s.c.) and orthotopic HCC. For treatments, 106 Ad-mAFP-transduced DC were inoculated s.c. followed by 106 CD40L-expressing DC injected intratumorally (i.t.). S.c. inoculation with Ad-mAFP-transduced DC, as vaccine, induced a delay of tumor-growth of AFP-positive HCC compared to controls. When s.c.-inoculation of Ad-mAFP-DC was combined with i.t.-application of Ad-CD40L-DC synergistic antitumoral effects were observed and complete remissions and long-term survival in 62% of tumor-bearing animals were achieved. Analysis of the tumor environment at different time points revealed that s.c.-vaccination with Ad-mAFP-DC seems to stimulate tumor-specific effector cells, allowing an earlier recruitment of effector T-cells and a Th1 shift within the tumors. After i.t. co-stimulation with Ad-CD40L-DC, production of Th1-cytokines was strongly increased and accompanied by a robust tumor infiltration of mature DC, activated CD4+-, CD8+-T-cells as well as reduction of regulatory T-cells. Moreover, Ad-CD40L-DC induced tumor cell apoptosis. Intratumoral co-stimulation with CD40L-expressing DC significantly improves vaccination with Ad-mAFP-DC in pre-established HCC in vivo. Combined therapy caused an early and strong Th1-shift in the tumor environment as well as higher tumor apoptosis, leading to synergistic tumor regression of HCC. Thus, CD40L co-stimulation represents a promising tool for improving DC-based immunotherapy of HCC.

The liver cancer immune microenvironment: Therapeutic implications for hepatocellular carcinoma

“…Recently, the combination of DC vaccine with ICIs has shown promising results 145,146. In preestablished in vivo subcutaneous and orthotopic HCCs, AFP‐DCs alone induced a significant reduction and a slight delay of tumor growth, whereas combination of AFP‐DCs and CD40L‐expressing DCs had a synergistic effect associated with an enhanced Th1‐cytokine level, tumor infiltration of cytotoxic T lymphocytes, and tumor apoptosis 147. Also, an orthotopic HCC mouse model treated with a DC vaccine in combination with a PD‐1 inhibitor showed longer overall survival than monotherapy and led to a greater reduction of tumor volume by inducing apoptosis 145.…”

The role of alpha-fetoprotein in the tumor microenvironment of hepatocellular carcinoma

“…The combination of the AFP-DCs vaccine with CD40 ligand-DCs vaccine has shown synergistic results. It changes the TME, enhances the tumor infiltration of cytotoxic T lymphocytes and DCs, and upregulates Th1-derived cytokines, leading to tumor apoptosis and regression ( 92 , 93 ). A phase I/II trial measuring immunization in HCC patients found that AFP-DCs vaccine can produce AFP-specific T cell responses with increasing IFN-γ in the environment of high oncofetal antigen ( 86 ).…”

Immune landscape and immunotherapy of hepatocellular carcinoma: focus on innate and adaptive immune cells

“…Many studies on novel DC vaccines have recently emerged, laying a solid theoretical foundation for the development of effective DC vaccines in the treatment of HCC. CD40L on activated CD4 + Th cells can communicate with CD40 on DCs to promote the secretion of Th1 cytokines by DCs, and the CD40L-DCs were confirmed to improve the anti-tumor activity of the AFP-DC vaccine in an orthotopic HCC mouse model, and the combination of them could significantly suppress tumor progression, accompanied by a robust Th1-shift in the TME and increased tumor cell apoptosis [ 227 ]. Furthermore, CSC/DC fusion cells could promote CTL accumulation in HCC and enhance anti-tumor immunity in animal experiments [ 228 ].…”