Reduced Argininosuccinate Synthetase Is a Predictive Biomarker for the Development of Pulmonary Metastasis in Patients with Osteosarcoma

Abstract

Pulmonary metastasis is the most significant prognostic determinant for osteosarcoma, but methods for its prediction and treatment have not been established. Using oligonucleotide microarrays, we compared the global gene expression of biopsy samples between seven osteosarcoma patients who developed pulmonary metastasis within 4 years after neoadjuvant chemotherapy and curative resection, and 12 patients who did not relapse. We identified argininosuccinate synthetase (ASS) as a gene differentially expressed with the highest statistical significance (Welch's t test, P = 2.2 × 10 −5). Immunohistochemical analysis of an independent cohort of 62 osteosarcoma cases confirmed that reduced expression of ASS protein was significantly correlated with the development of pulmonary metastasis after surgery (log-rank test, P < 0.05). Cox regression analysis revealed that ASS was the sole significant predictive factor (P = 0.039; hazard ratio, 0.319; 95% confidence interval, 0.108-0.945). ASS is one of the enzymes required for the production of a nonessential amino acid, arginine. We showed that osteosarcoma cells lacking ASS expression were auxotrophic for arginine and underwent G 0 -G 1 arrest in arginine-free medium, suggesting that an arginine deprivation therapy could be effective in patients with osteosarcoma. Recently, phase I and II clinical trials in patients with melanoma and hepatocellular carcinoma have shown the safety and efficacy of plasma arginine depletion by stabilized arginine deiminase. Our data indicate that in patients with osteosarcoma, reduced expression of ASS is not only a novel predictive biomarker for the development of metastasis, but also a potential target for pharmacologic intervention. Mol Cancer Ther; 9(3); 535-44. ©2010 AACR.

Prognostic and Therapeutic Impact of Argininosuccinate Synthetase 1 Control in Bladder Cancer as Monitored Longitudinally by PET Imaging

“…We show that despite exhibiting a poorer prognosis, ASS1-negative bladder cancer is amenable to dual targeting with ADI-PEG20 and antifolates with early treatment response monitoring by [ 18 F]FLT-PET. Our bladder cancer cell line studies reveal that unmethylated ASS1 functions as a bona fide tumor suppressor and is consistent with recent studies in osteosarcomas and myxofibrosarcomas (11,12). Exactly how ASS1 promoter methylation leads to a requirement for exogenous arginine, which promotes increased tumor cell proliferation and invasion is unclear.…”

“…Inactivation of the pleiotropic enzyme, argininosuccinate synthetase 1 (ASS1), with key roles in the urea cycle, citrulline-NO cycle, and arginine biosynthesis has emerged as a principal driver of tumoral arginine auxotrophy, with evidence for epigenetic silencing and hypoxia-inducible factor-1a (HIF-1a)-mediated transcriptional repression of ASS1 (5,8,9). Significantly, ASS1 loss has been associated with decreased overall survival in ovarian cancer and myxofibrosarcoma, and reduced metastasis-free survival in osteosarcoma, implicating a tumor-suppressor function for this metabolic gene (10)(11)(12). Thus, arginine deprivation is being tested increasingly in the clinic, modeled on the successful introduction of another amino acid depletor, namely asparaginase, in the management of acute lymphoblastic leukemia five decades ago (13).…”

ASS1as a Novel Tumor Suppressor Gene in Myxofibrosarcomas: Aberrant Loss via Epigenetic DNA Methylation Confers Aggressive Phenotypes, Negative Prognostic Impact, and Therapeutic Relevance

“…These findings highlight the antiproliferative function of ASS1 in suppressing the growth of myxofibrosarcomas, which was associated with the induction of G 1 arrest, most likely resulting from downregulation of cyclin E. Distant dissemination is the leading cause of mortality in sarcomas, and is a great hindrance to treatment (31,32). In osteosarcomas of the bone, reduced ASS1 immunoexpression was reported to be a biomarker of pulmonary metastasis after neoadjuvant chemotherapy and curative resection, whereas there was no mechanistic elucidation of the ASS1 deficiency with enhanced tumor metastasis (36). Herein, we further reinforced the role of ASS1 in suppressing metastasis.…”

Identification of candidate drugs for the treatment of metastatic osteosarcoma through a subpathway analysis method

“…The microarray dataset GSE14827 was downloaded from the GEO database (National Center of Biotechnology Information, Bethesda, MD, USA; www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE14827). The dataset included biopsy samples from 9 patients with OS who developed pulmonary metastases ≤4 years following neoadjuvant chemotherapy and curative resection, and 18 patients who did not relapse in this time frame (7). All tumor samples in the dataset were obtained through diagnostic incisional biopsies from primary sites of OS prior to neoadjuvant chemotherapy at the National Cancer Center Hospital (Tokyo, Japan) between March 1996 and September 2007 (7).…”

“…The introduction of preoperative high-dose combined chemotherapy in the last three decades has significantly improved the disease-free 5-year survival rate of young patients (<40 years old) to ~50% (6). However, OS is highly aggressive and numerous patients with OS develop metastases, primarily in the lung, even following resection of the primary tumor (2,7). Furthermore, metastatic OS frequently exhibits resistance to conventional chemotherapies that were effective for treatment of the primary tumor and >30% of metastatic OS cases do not respond to chemotherapy (4,8,9).…”