ASS1 as a novel tumor suppressor gene in myxofibrosarcomas: Aberrant loss via epigenetic DNA methylation confers aggressive phenotypes, negative prognostic impact, and therapeutic relevance

Hsuan Ying Huang, Wen Ren Wu, Yu Hui Wang, Jun Wen Wang, Fu Min Fang, Jen Wei Tsai, Shau Hsuan Li, Hsiao Chin Hung, Shih Chen Yu, Jui Lan, Yow Ling Shiue, Chung-Hsi Hsing, Li Tzong Chen, Chien Feng Li

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Abstract

Purpose: The principal goals were to identify and validate targetable metabolic drivers relevant to myxofibrosarcoma pathogenesis using a published transcriptome. Experimental Design: As the most significantly downregulated gene regulating amino acid metabolism, argininosuccinate synthetase ( ASS1) was selected for further analysis by methylation-specific PCR, pyrosequencing, and immunohistochemistry of myxofibrosarcoma samples. The roles of ASS1 in tumorigenesis and the therapeutic relevance of the arginine-depriving agent pegylated arginine deiminase (ADI-PEG20) were elucidated in ASS1-deficient myxofibrosarcoma cell lines and xenografts with and without stable ASS1 reexpression. Results: ASS1 promoter hypermethylation was detected in myxofibrosarcoma samples and cell lines and was strongly linked to ASS1 protein deficiency. The latter correlated with increased tumor grade and stage and independently predicted a worse survival. ASS1-deficient cell lines were auxotrophic for arginine and susceptible to ADI-PEG20 treatment, with dose-dependent reductions in cell viability and tumor growth attributable to cell-cycle arrest in the S-phase. ASS1 expression was restored in 2 of 3 ASS1-deficient myxofibrosarcoma cell lines by 5-aza-2′-deoxycytidine, abrogating the inhibitory effect of ADI-PEG20. Conditioned media following ASS1 reexpression attenuated HUVEC tube-forming capability, which was associated with suppression of MMP-9 and an antiangiogenic effect in corresponding myxofibrosarcoma xenografts. In addition to delayed wound closure and fewer invading cells in a Matrigel assay, ASS1 reexpression reduced tumor cell proliferation, induced G1-phase arrest, and downregulated cyclin E with corresponding growth inhibition in soft agar and xenograft assays. Conclusions: Our findings highlight ASS1 as a novel tumor suppressor in myxofibrosarcomas, with loss of expression linked to promoter methylation, clinical aggressiveness, and sensitivity to ADI-PEG20.

Original languageEnglish
Pages (from-to)2861-2872
Number of pages12
JournalClinical Cancer Research
Volume19
Issue number11
DOIs
Publication statusPublished - Jun 1 2013
Externally publishedYes

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ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Huang, H. Y., Wu, W. R., Wang, Y. H., Wang, J. W., Fang, F. M., Tsai, J. W., Li, S. H., Hung, H. C., Yu, S. C., Lan, J., Shiue, Y. L., Hsing, C-H., Chen, L. T., & Li, C. F. (2013). ASS1 as a novel tumor suppressor gene in myxofibrosarcomas: Aberrant loss via epigenetic DNA methylation confers aggressive phenotypes, negative prognostic impact, and therapeutic relevance. Clinical Cancer Research, 19(11), 2861-2872. https://doi.org/10.1158/1078-0432.CCR-12-2641