<b>Conclusions:</b> Amplification or higher expression of PD-L1 significantly and independently correlated with unfavorable survival in HCC patients, authenticating the PD-1/PD-L1 axis as rational immunotherapeutic targets for HCC.
<b>Methods:</b> In an observational study of HCC liver samples, we determined the incidence of PD-L1 and immune cell (IC) infiltrates, and signs of TGF-β activity.
PD-L1 expression plays a critical role in the pathogenesis of human HCC, suggesting that it might be used as a new biomarker to predict the disease progression and prognosis.
PD-L1 expression was positively correlated with MMP-12 expression, indicating that MMP-12 may promote the development of HCC through the up-regulation of PD-L1.
Additionally, the disruption of PD-1 could protect the GPC3-CAR T cells from exhaustion when combating with native PD-L1-expressing HCC, as the levels of Akt phosphorylation and anti-apoptotic protein Bcl-xL expression in PD-1 deficient GPC3-CAR T cells were significantly higher than those in wild-type GPC3-CAR T cells after coculturing with PLC/PRF/5.
Although there was no significant difference of PD-L1 expression on CD14<sup>+</sup> population among three disease groups, further analysis demonstrated that the frequency of CD14<sup>+</sup>PD-L1<sup>+</sup> population was negatively correlated with HBV DNA load, the levels of alanine aminotransaminase (ALT), and the levels of aspartate aminotransferase (AST), respectively, at CHB stage, while it did not present significant correlation with such parameters at LC stage and was only positively correlated with HBV DNA load at HCC stage.
As preliminary step toward this goal, we have investigated the expression of antigen presenting molecules (HLA class I and class II) and immune checkpoints (PD-1 and PD-L1) in 43 HCC samples from distinct patients and in HCC cell lines.
At the same time, a combinational therapy with HIF-1α inhibitors in conjunction with PD-L1 blockade may be beneficial for HCC patients with co-overexpression in the future.
Besides oncolytic viruses, vaccines, or immune cell infusions, first results from early-phase clinical trials particularly encourage the use of immune checkpoint inhibitors against PD-1/PD-L1 and CTLA-4 for HCC.
Besides, celecoxib treatment increased the infiltration of cytotoxic T lymphocytes (CTLs) and reduced the number of regulatory T cells (Tregs), tumor-associated macrophages (TAMs), and the expression of immune checkpoint PD-L1 in HCC tissues during epirubicin therapy.
Blocking the PD-1/PD-L1 axis in dendritic cell-stimulated Cytokine-Induced Killer Cells with pembrolizumab enhances their therapeutic effects against hepatocellular carcinoma.
Blocking the programmed death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway in hepatocellular carcinoma (HCC) is a very promising approach in immunotherapy.
Concomitant with patient-derived M-MDSC suppression by i-BET762, combined treatment with anti-PD-L1 synergistically enhanced TILs, resulting in tumour eradication and prolonged survival in the fibrotic-HCC mouse model.
Expression of CXCL12, PD-L1 and of surrogate markers for tumour hypoxia was evaluated at messenger RNA (mRNA) level in a cohort of HCC patients from The Cancer Genome Atlas and immunohistochemically in an independent cohort from the University Hospital of Bonn.
Finally, using SP263, the mean number of PD-L1-positive cells was 11.3 ± 12.6 in HCC from deceased patients, versus 4.7 ± 5.2 in alive patients (p = 0.039).