Peripheral blood-based cell signature indicates response to interstitial brachytherapy in primary liver cancer

PURPOSE

Biomarkers are essential to implement personalized therapies in cancer treatment options. As primary liver tumors are increasing and treatment is coupled to liver function and activation of systemic cells of the immune system, we investigated blood-based cells for their ability to predict response to local ablative therapy.

METHODS

We analyzed peripheral blood cells in 20 patients with primary liver cancer at baseline and following brachytherapy. In addition to platelets, leukocytes, lymphocytes, monocytes, neutrophils and most common ratios PLR, LMR, NMR and NLR, we investigated T cell and NKT cell populations of 11 responders and 9 non-responders using flow cytometry.

RESULTS

We have found a peripheral blood cell signature that differed significantly between responders and non-responders treated with interstitial brachytherapy (IBT). At baseline, non-responders featured higher numbers of platelets, monocytes and neutrophils, a higher platelet-to-lymphocyte ratio and an increase in the NKT cell population with a concurrent reduction in CD16 + NKT cells. Simultaneously, a lower percentage of CD4 + T cells was present in non-responders, as also reflected in a lower CD4/8 ratio. CD45RO + memory cells were lower in both, CD4 + and CD8 + T cell populations whereas PD-1 + T cells were only present in the CD4 + T cell population.

CONCLUSION

Baseline blood-based cell signature may function as a biomarker to predict response following brachytherapy in primary liver cancer.

Prediction of Protumorigenic Effects after Image-Guided Radiofrequency Ablation of Hepatocellular Carcinoma Using Biomarkers

PURPOSE

To perform radiofrequency (RF) ablation of hepatocellular carcinoma (HCC) and to assess serological and histopathological markers of tumorigenesis in distant untreated tumors to determine whether these were associated with unfavorable outcomes such as early relapse and increased biological aggressiveness.

MATERIALS AND METHODS

The study cohort comprised 13 patients from a prospective single-arm study. All patients underwent 2 ablation sessions of multifocal HCC nodules 14 days apart. Core biopsy samples of untreated tumors were acquired at baseline and at the time of the second ablation session. Samples were stained immunohistochemically with Ki-67 (proliferation) and CD34 (microvasculature). Blood plasma was obtained at baseline and 2 days after the initial ablation session and analyzed for hepatocyte growth factor (HGF), vascular endothelial growth factor C, and angiopoietin-2 using an enzyme-linked immunosorbent assay. The clinical follow-up period ranged from 7 to 25 months. Patients were stratified as responders (complete remission or limited and delayed recurrence at >6 months; n = 6) or nonresponders (any recurrence within 6 months or >3 new tumors or any new tumor of >3 cm thereafter; n = 7).

RESULTS

In 3 of 7 nonresponders, the Ki-67 index markedly increased in untreated tumors, whereas Ki-67 was stable in all responders. Microvascular density strongly increased in a single nonresponder only. HGF and angiopoietin-2 increased by >30% in 3 of 7 and 4 of 7 nonresponders, respectively, whereas they were stable or decreased in responders. Overall, ≥2 biomarkers were elevated in 6 of 7 (85.7%) nonresponders, whereas 4 of 6 responders demonstrated no increased biomarker and 2 patients demonstrated increase in 1 biomarker only (P = .002).

CONCLUSIONS

RF ablation of HCC can produce protumorigenic factors that induce effects in distant untreated tumors. These may potentially function as biomarkers of clinical outcome.

Early monocyte response following local ablation in hepatocellular carcinoma

Local ablative therapies are established treatment modalities in the treatment of early- and intermediate-stage hepatocellular carcinoma (HCC). Systemic effects of local ablation on circulating immune cells may contribute to patients' response. Depending on their activation, myeloid cells are able to trigger HCC progression as well as to support anti-tumor immunity. Certain priming of monocytes may already occur while still in the circulation. By using flow cytometry, we analyzed peripheral blood monocyte cell populations from a prospective clinical trial cohort of 21 HCC patients following interstitial brachytherapy (IBT) or radiofrequency ablation (RFA) and investigated alterations in the composition of monocyte subpopulations and monocytic myeloid-derived suppressor cells (mMDSCs) as well as receptors involved in orchestrating monocyte function. We discovered that mMDSC levels increased following both IBT and RFA in virtually all patients. Furthermore, we identified varying alterations in the level of monocyte subpopulations following radiation compared to RFA. (A) Liquid biopsy liquid biopsy of circulating monocytes in the future may provide information on the inflammatory response towards local ablation as part of an orchestrated immune response.

Tumor-Associated Macrophages-Implications for Molecular Oncology and Imaging

Tumor-associated macrophages (TAMs) represent the largest group of leukocytes within the tumor microenvironment (TME) of solid tumors and orchestrate the composition of anti- as well as pro-tumorigenic factors. This makes TAMs an excellent target for novel cancer therapies. The plasticity of TAMs resulting in varying membrane receptors and expression of intracellular proteins allow the specific characterization of different subsets of TAMs. Those markers similarly allow tracking of TAMs by different means of molecular imaging. This review aims to provides an overview of the origin of tumor-associated macrophages, their polarization in different subtypes, and how characteristic markers of the subtypes can be used as targets for molecular imaging and theranostic approaches.

Glutathione redox cycle is an important defense system of endothelial cells against chronic hyperoxia

Exposure of cultured pulmonary artery endothelial cells to 95% O2 resulted in the following sequence of events: decrease in [3H]thymidine incorporation after 24 h; increase of intracellular glutathione (GSH) and loss of cellular protein after 48 h; increase of spontaneous and decrease of provoked prostacyclin formation as well as increased release of cellular LDH after 72 h. This oxygen toxicity model was used to study the following 2 questions. (1) What is the relative importance of the GSH redox cycle compared to catalase as antioxidative defense against hyperoxia? Endothelial cells were grown in selenium-depleted medium to inhibit glutathione peroxidase activity. Endothelial GSH biosynthesis was inhibited by buthionine sulfoximine. Catalase activity was reduced by aminotriazole. Endothelial cells with an impaired GSH redox cycle were easily killed by hyperoxia within 24 h, while inhibition of catalase did not enhance the susceptibility of endothelial cells to hyperoxia. (2) Can endothelial GSH content be increased by exogenous sulfhydryl reagents and does this result in an increase of endothelial cells' resistance to hyperoxia? Exogenous GSH, N-acetylcysteine, cysteine, and L-2-oxothiazolidine-4-carboxylate (L-2-oxo) increased intracellular GSH. All sulfhydryl reagents (with the exception of L-2-oxo) protected endothelial cells from hyperoxia. Concentrations of exogenous GSH and N-acetylcysteine that did not increase intracellular GSH reduced hyperoxia-induced endothelial cell injury. Thus the capacity of the GSH redox cycle rather than intracellular GSH levels or catalase determines endothelial cells' resistance to hyperoxia.