Proteomic Analysis of Neuroblastoma Microenvironment: Effect of the Host–Tumor Interaction on Disease Progression

Potential role of WSB1 isoforms in growth and survival of neuroblastoma cells

BACKGROUND

WD repeat and SOCS box containing protein 1 (WSB1) generates three isoforms that were found to play a role in cancer cell growth and tumor progression. We have studied their expression in neuroblastoma (NB).

METHODS

The behavior of the expression levels of the WSB1 isoforms was analyzed in NB cell lines, in an in vivo NB xenograft mouse model, and in primary NB tumors using real-time PCR. Effective WSB1 small interfering RNAs were transfected into cultured NB cell lines, and cell viability was analyzed using XTT assay and flow cytometry.

RESULTS

A significant predominance of the WSB1 isoform 3 (WSB1(3)) expression level was demonstrated in all NB systems examined. Correspondingly, combination of WSB1(3) silencing together with WSB1 isoforms 1+2 silencing in NB cells showed reduced growth, enhanced apoptosis rate, and increased sensitivity to chemotherapeutic agents, specifically related to low expression of WSB1(3).

CONCLUSION

Our results point to a possible differential role of WSB1 isoforms in NB and suggest WSB1(3) as a target for therapy in NB.

Application of proteomics to soft tissue sarcomas

Soft tissue sarcomas are rare and account for less than 1% of all malignant cancers. Other than development of intensive therapies, the clinical outcome of patients with soft tissue sarcoma remains very poor, particularly when diagnosed at a late stage. Unique mutations have been associated with certain soft tissue sarcomas, but their etiologies remain unknown. The proteome is a functional translation of a genome, which directly regulates the malignant features of tumors. Thus, proteomics is a promising approach for investigating soft tissue sarcomas. Various proteomic approaches and clinical materials have been used to address clinical and biological issues, including biomarker development, molecular target identification, and study of disease mechanisms. Several cancer-associated proteins have been identified using conventional technologies such as 2D-PAGE, mass spectrometry, and array technology. The functional backgrounds of proteins identified were assessed extensively using in vitro experiments, thus supporting expression analysis. These observations demonstrate the applicability of proteomics to soft tissue sarcoma studies. However, the sample size in each study was insufficient to allow conclusive results. Given the low frequency of soft tissue sarcomas, multi-institutional collaborations are required to validate the results of proteomic approaches.