Endothelial progenitor cell number and ERK phosphorylation serve as predictive and prognostic biomarkers in advanced hepatocellular carcinoma patients treated with sorafenib.

Sorafenib is an oral anti-angiogenic multi-kinase inhibitor used for systemic therapy in patients with advanced hepatocellular carcinoma (HCC) who are not suitable candidates for surgery or liver transplantation. An earlier study conducted with HCC tumor tissue suggested that ERK phosphorylation (pERK), a downstream target of sorafenib, may serve as a potential biomarker for therapeutic efficacy of sorafenib. However, no study thus far has utilized a minimal invasive procedure to predict HCC patient responsiveness to sorafenib. We evaluated the biomarker utility of circulating endothelial progenitor cells (EPCs) frequency and intracellular pERK levels in EPCs in peripheral blood obtained pre- and post-sorafenib therapy or after transarterial chemoembolistaion (TACE). A statistically significant reduction in the level of ERK phosphorylation and in the absolute number of EPCs was detected following in vivo sorafenib treatment (p < 0 .01 for both). In contrast, the decrease in the level of ERK phosphorylation and EPC number was either marginally significant or insignificant in patients treated with TACE (p = 0.05 and 0.06, respectively). In vitro sorafenib treatment of pre- and post-samples from the same patient cohort inhibited ERK phosphorylation levels in EPCs and decreased the number of EPCs at all doses tested (p = 0.01). Our findings support that the evaluation of both the circulating EPC frequency and the level of ERK phosphorylation in EPCs may serve as potential non-invasive biomarkers of sorafenib efficacy, both as predictor of treatment outcome and efficacy during drug treatment.

PD-1+ and Foxp3+ T cell reduction correlates with survival of HCC patients after sorafenib therapy.

BACKGROUND: Sorafenib is an oral antiangiogenic agent administered in advanced-stage hepatocellular carcinoma (HCC). Based on preclinical and human studies, we hypothesized that, in addition to its antiangiogenic properties, sorafenib may beneficially reduce the extent of the immunosuppressive network in HCC patients. To test this hypothesis, we examined whether alterations in the immunosuppressive burden of advanced-stage HCC patients correlated with clinical outcome. METHODS: In before and after sorafenib treatment, blood samples collected from 19 patients with advanced HCC, the frequency of PD-1+ T cells, Tregs, and myeloid derived suppressor cells (MDSC) were quantified by multiparameter FACS. Cytokine levels in plasma were determined by ELISA. RESULTS: Overall survival (OS) was significantly impacted by the reduction in the absolute number of both CD4+PD-1+ T cells and CD8+PD-1+ T cells following sorafenib treatment. Significant decreases in the frequency and absolute number of Foxp3+ Tregs were also observed, and a statistically significant improvement in OS was noted in patients exhibiting a greater decrease in the number of Foxp3+ Tregs. The ratio of CD4+CD127+PD-1- T effector cells to CD4+Foxp3+PD-1+ Tregs was significantly increased following treatment with sorafenib. Increased frequency of CD4+CD127+ T effector cells in the posttreatment samples significantly correlated with OS. CONCLUSION: This study is the first to our knowledge to demonstrate the potent immunomodulatory effects of sorafenib therapy on PD-1+ T cells and Tregs and the ensuing correlation with survival. These phenotypes could serve as predictive biomarkers to identify HCC patients who are likely to benefit from sorafenib treatment. TRIAL REGISTRATION: Registration is not required for observational studies. FUNDING: This study was supported by NCI Core Grant to RPCI (NIH P30 CA016056) and discretionary funds to Y. Thanavala.

T-regulatory cells and programmed death 1+ T cells contribute to effector T-cell dysfunction in patients with chronic obstructive pulmonary disease.

RATIONALE: Previous studies from our laboratory have shown that peripheral blood mononuclear cells (PBMCs) from patients with chronic obstructive pulmonary disease (COPD) prone to exacerbations with nontypeable Haemophilus influenzae have impaired responses to lipoprotein P6. We hypothesized that an underlying immunosuppressive network could be responsible for the defective antibacterial immunity observed in these patients. We evaluated T regulatory cells (Tregs), myeloid-derived suppressor cells (MDSC), and exhausted T effector cells (programmed death 1 [PD-1](+)) in patients with COPD, because these cells are known to play a pivotal role in suppressing immune responses. OBJECTIVES: We performed an in-depth characterization of Tregs, T effector cells, and MDSC in COPD and correlated their levels and function with disease severity. METHODS: Treg, effector T cell, and MDSC frequency from patients with COPD and healthy subjects' PBMCs were analyzed by flow cytometry. Treg immunosuppressive capacity was measured by in vitro suppression assay. The frequency of interferon-γ producing T cells and T-cell proliferation were measured after blocking CTLA-4 and PD-1. Plasma proinflammatory and immunosuppressive cytokine levels were measured. MEASUREMENTS AND MAIN RESULTS: Significantly increased levels of Tregs, MDSC, and PD-1(+) exhausted effector T cells were present in patients with COPD compared with healthy subjects. Tregs from patients with COPD suppressed P6-specific T-cell proliferation to a greater extent than Tregs from healthy subjects. Plasma levels of Treg-generated cytokines, IL-10, and transforming growth factor-ß were elevated. Blockade of CTLA-4 resulted in significant augmentation of T-cell IFN-γ production in patients with COPD. CONCLUSIONS: Functionally suppressive Tregs, MDSCs, and exhausted PD-1(+) T cells contribute to effector T-cell dysfunction in COPD.