Heparanase activity in alveolar and embryonal rhabdomyosarcoma: implications for tumor invasion

Valentina Masola,Maurizio Onisto,Claudio Maran,Evelyne Tassone,Angelica Zin,Angelo Rosolen

doi:10.1186/1471-2407-9-304

Abstract

BackgroundRhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma of childhood including two major histological subtypes, alveolar (ARMS) and embryonal (ERMS) RMS. Like other human malignancies RMS possesses high metastatic potential, more pronounced in ARMS than in ERMS. This feature is influenced by several biological molecules, including soluble factors secreted by tumor cells, such as heparanase (HPSE). HPSE is an endo-β-D-glucuronidase that cleaves heparan sulphate proteoglycans.MethodsWe determined HPSE expression by Western blot analysis in ARMS and ERMS cells lines and activity in supernatants by an ELISA assay. Stable HPSE silencing has been performed by shRNA technique in RH30 and RD cell lines and their invasiveness has been evaluated by Matrigel-invasion assay. HPSE activity and mRNA expression have also been quantified in plasma and biopsies from RMS patients.ResultsHPSE expression and activity have been detected in all RMS cell lines. Stable HPSE silencing by shRNA technique determined a significant knockdown of gene expression equal to 76% and 58% in RH30 and RD cell lines respectively and induced a less invasive behaviour compared to untreated cells. Finally, we observed that HPSE mRNA expression in biopsies was higher than in foetal skeletal muscle and that plasma from RMS patients displayed significantly more elevated HPSE levels than healthy subjects with a trend to higher levels in ARMS.ConclusionIn conclusion, our data demonstrate for the first time HPSE expression and activity in RMS and highlight its involvement in tumor cell invasion as revealed by shRNA silencing. Moreover, HPSE expression in RMS patients is significantly higher with respect to healthy subjects. Further studies are warranted to assess possible relationships between HPSE and clinical behaviour in RMS.

Highlights

Rhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma of childhood including two major histological subtypes, alveolar (ARMS) and embryonal (ERMS) RMS
HPSE expression in RMS cell lines In order to define whether heparanase was expressed in the two major RMS histotypes and whether gene expression correlated with their different metastatic potential, HPSE expression was evaluated in alveolar rhabdomyosarcoma (ARMS) and embryonal rhabdomyosarcoma (ERMS) cell lines
ARMS cell lines displayed two different patterns: RH30 and RH4 cell lines were characterized by high levels of the active isoform and low levels of the inactive one, whereas RH18 and RH28 showed a low expression of the active enzyme

Summary

Introduction

Rhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma of childhood including two major histological subtypes, alveolar (ARMS) and embryonal (ERMS) RMS. Like other human malignancies RMS possesses high metastatic potential, more pronounced in ARMS than in ERMS This feature is influenced by several biological molecules, including soluble factors secreted by tumor cells, such as heparanase (HPSE). RMS belongs to the broader category of small blue round cell tumors of childhood and histologically resembles normal foetal skeletal muscle [1]. It can be classified into two main histological subtypes with distinct appearances and clinical behaviours. The rarer alveolar type (ARMS) arises mainly in the extremities and trunk It is associated with worse prognosis and higher disease stage at diagnosis. The embryonal rhabdomyosarcoma (ERMS) usually affects younger children, at more favourable sites, and shows a less aggressive clinical behaviour than ARMS [2,3]

Methods

Results

Discussion

Conclusion