Suppression of Soft Tissue Sarcoma Growth by a Host Defense-Like Lytic Peptide

Irina Agoulnik,Lars Steinstraesser,Sammy Al-Benna,Cornelius Schubert,Hanns Hatt,Jennifer Hauk,Hans-Ulrich Steinau,Yechiel Shai,Ingo Stricker,Frank Jacobsen

doi:10.1371/journal.pone.0018321

Abstract

BackgroundSoft tissue sarcoma (STS) is an anatomically and histologically heterogeneous neoplasia that shares a putative mesenchymal cell origin. The treatment with common chemotherapeutics is still unsatisfying because of association with poor response rates. Although evidence is accumulating for potent oncolytic activity of host defense peptides (HDPs), their potential therapeutic use is often limited by poor bioavailability and inactivation in serum. Therefore, we tested the designer host defense-like lytic D,L-amino acid peptide [D]-K3H3L9 on two STS cell lines in vitro and also in an athymic and syngeneic mouse model. In recent studies the peptide could show selectivity against prostate carcinoma cells and also an active state in serum.Methods In vitro the human synovial sarcoma cell line SW982, the murine fibrosarcoma cell line BFS-1 and primary human fibroblasts as a control were exposed to [D]-K3H3L9, a 15mer D,L-amino acid designer HDP. Cell vitality in physiological and acidic conditions (MTT-assay), cell growth (BrdU) and DNA-fragmentation (TUNEL) were investigated. Membrane damage at different time points could be analyzed with LDH assay. An antibody against the tested peptide and recordings using scanning electron microscopy could give an inside in the mode of action. In vivo [D]-K3H3L9 was administered intratumorally in an athymic and syngeneic (immunocompetent) mouse model with SW982 and BFS-1 cells, respectively. After three weeks tumor sections were histologically analyzed.ResultsThe peptide exerts rapid and high significant cytotoxicity and antiproliferating activity against the malignant cell lines, apparently via a membrane disrupting mode of action. The local intratumoral administration of [D]-K3H3L9 in the athymic and syngeneic mice models significantly inhibited tumor progression. The histological analyses of the tumor sections revealed a significant antiproliferative, antiangiogenic activity of the treatment group.ConclusionThese findings demonstrate the in vitro and in vivo oncolytic activity of [D]-K3H3L9 in athymic and syngeneic mouse models.

Highlights

Soft tissue sarcomas (STS) are a group of histologically and genetically diverse neoplasms that account for approximately 1% of all adult malignancies [1]
Cell culture The SW982 human synovial sarcoma cell line (Cell Line Service (CLS), Eppelheim, Germany), last authenticated via nonaplex PCR in July, 2008) was grown in DMEM supplemented with 10% FCS (Thermo Fisher Scientific Inc., Waltham, MA, USA) and 1% penicillin/streptomycin (PAA laboratories, Pasching, Austria)
The viability of the cells after treatment with [D]-K3H3L9 was determined at physiological and acidic

Summary

Introduction

Soft tissue sarcomas (STS) are a group of histologically and genetically diverse neoplasms that account for approximately 1% of all adult malignancies [1]. Effective treatment usually requires surgical ablation in combination with radiotherapy and/or chemotherapy as the clinical gold standard and could improve the local control rates [4]. In spite of this promising therapeutic treatment local relapse still occurs in up to. Soft tissue sarcoma (STS) is an anatomically and histologically heterogeneous neoplasia that shares a putative mesenchymal cell origin. Evidence is accumulating for potent oncolytic activity of host defense peptides (HDPs), their potential therapeutic use is often limited by poor bioavailability and inactivation in serum. In recent studies the peptide could show selectivity against prostate carcinoma cells and an active state in serum

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