Increased PD-L1 and T-cell infiltration in the presence of HLA class I expression in metastatic high-grade osteosarcoma: a rationale for T-cell-based immunotherapy

Abstract

IntroductionImmunotherapy may be an excellent choice for treating osteosarcoma given its exceptionally high genomic instability, potentially generating neoantigens. In this study, we aim to investigate the HLA class I expression, PD-L1 and tumour-infiltrating lymphocytes in primary osteosarcomas and relapses/metastases, as well as their changes during disease progression.Materials and methodsTumour samples from multiple stages of the disease (pretreatment biopsies, surgical resections of primary osteosarcomas, relapses and metastases) were collected and stained for HLA-A (HCA2), HLA-B/C (HC10), β2-microglobulin and PD-L1 using immunohistochemistry on whole sections. Density and type of T-cell infiltrate were characterised by a triple immunofluorescent staining CD3-CD8-FOXP3.ResultsOverall, 85 formalin-fixed, paraffin-embedded blocks from 25 osteosarcoma patients were included. HLA class I expression was detected in 94% of osteosarcomas (strongly positive in 56%, heterogeneous in 38%) and negative or weakly positive in 6%, without differences between the stages of the disease. HLA-A expression was more frequently negative than HLA-B/C. Tumour-infiltrating lymphocytes were highly heterogeneous and mainly observed in tumour areas with expression of HLA class I. Density of T cells was significantly higher in metastases than in primary tumours and local relapses (p = 0.0003). Positive PD-L1 expression was found in 13% of primary tumours, 25% of relapses and 48% of metastases and correlated with a high T-cell infiltrate (p = 0.002).ConclusionAn increased number of tumour-infiltrating T cells and PD-L1 expression in metastases compared with primary tumours, suggesting accessibility for T cells, could imply that osteosarcoma patients with metastatic disease may benefit from T-cell-based immunotherapy.Electronic supplementary materialThe online version of this article (doi:10.1007/s00262-016-1925-3) contains supplementary material, which is available to authorized users.

Evodiamine Induces Apoptosis, G2/M Cell Cycle Arrest, and Inhibition of Cell Migration and Invasion in Human Osteosarcoma Cells via Raf/MEK/ERK Signalling Pathway

“…In the present study, we observed that Evodiamine caused a significant decrease in the expression of cyclin B1, Cdc25c, and Cdc2, favoring cell cycle arrest at G2/M phase. Metastasis of osteosarcoma is very challenging to manage; therefore, it is important to discover molecules that can inhibit the metastasis of osteosarcoma cells [21]. In the present study, we observed that Evodiamine inhibited the migration and invasion of U2OS osteosarcoma cells.…”

Assessment of programmed death‐ligand 1 expression and tumor‐associated immune cells in pediatric cancer tissues

“…Although current concepts hold that PD-L1 expression may serve as a marker of lymphocyte activation and production of interferon-c within the tumor microenvironment, 57 we did not observe a correlation between lymphocyte infiltration and PD-L1 expression in this data set. 54 Together, our data demonstrate that significant subsets of pediatric tumors express PD-L1, either on the tumor itself or in the microenvironment. Previous studies have reported a predominance of macrophages in pediatric tumors 58,59 ; whereas, in our samples, a minority of tumors demonstrated macrophage infiltration, and these macrophages often expressed PD-L1.…”

“…A study by Chowdhury et al found higher rates of PD-L1 expression in a series of 115 pediatric tumors, 55 but their study relied on an antibody that was not validated for the detection of PD-L1. 30,31,54 Third, emerging evidence suggests that pediatric cancer genomes evolve extensively after exposure to chemoradiotherapy and attain significantly larger mutational burdens. Although current concepts hold that PD-L1 expression may serve as a marker of lymphocyte activation and production of interferon-c within the tumor microenvironment, 57 we did not observe a correlation between lymphocyte infiltration and PD-L1 expression in this data set.…”

The contribution of immune infiltrates and the local microenvironment in the pathogenesis of osteosarcoma

“…Similarly, osteosarcoma cells express B7-H3 which is correlated with the aggressiveness of the disease and metastatic capacity [85,86]. Program Death Ligand-1 (PDL-1) and PDL-2 were also detectable in all osteosarcoma cases [89][90][91][92][93][94].…”