OBJECTIVETo detect the expression level of asparagine synthetase (ASNS) in patients with relapsed or refractory extranodal NK/T cell lymphoma and explore its clinical significance.

METHODSTen patients with relapsed or refractory extranodal NK/T cell lymphoma admitted in our department from January, 2013 to January, 2016 were analyzed. The diagnoses were confirmed by pathological and immunohistochemical examination following failed chemotherapies in all cases. Branched DNA-liquidchip technique (bDNA-LCT) was used for detecting ASNS mRNA expression in paraffin-embedded tissue sections in the 10 cases of relapsed or refractory extranodal NK/T cell lymphoma and in 5 cases of chronic rhinitis. The correlations were analyzed between ASNS expression and the clinicopathological features and outcomes of the patients with failed chemotherapy regimens containing asparaginasum.

RESULTSSix out of the 10 patients with relapsed or refractory extranodal NK/T cell lymphoma died due to diseaseprogression. The expression level of ASNS was significantly higher in the lymphoma tissues than in tissue specimens of chronic rhinitis (P<0.05). The expression level of ASNS was associated with the International Prognostic Index (P=0.023) in patients with relapsed or refractory extranodal NK/T cell lymphoma, and Kaplan-Meier curve showed that a high ASNS expression was correlated with a reduced overall survival and progression-free survival of the patients.

CONCLUSIONAsparaginasum-based chemotherapy regimens are recommended for treatment of relapsed or refractory extranodal NK/T cell lymphoma with low ASNS expressions.

Aspartate-Ammonia Ligase ; metabolism ; Disease-Free Survival ; Humans ; Lymphoma, Extranodal NK-T-Cell ; enzymology ; Recurrence

This study was purposed to explore the relationship between asparagine synthetase (AsnS) mRNA expression level and the sensitivity of leukemic cell lines to L-asparaginase. The AsnS mRNA expression level in 8 cell lines (Jurkat, HL-60, U937, NB4, THP-1, Namalwa, Karpas299 and K562) was determined by real-time quantitative PCR (RQ-PCR) based on fluorescence dye Eva Green before and after treatment with L-Asp, and the cell proliferation rates were analyzed by CCK-8 assay. The results showed that there was a significant disparity of AsnS expression level in 8 cell lines, and there were significant increases of AsnS expression level in cells co-cultured with L-Asp (p < 0.05). Of all these eight cell lines, cells sensitive to L-asparaginase had lower AsnS expression level and cells resistant to L-asparaginase had higher AsnS expression. U937 which was the most sensitive to L-asparaginase had the lowest AsnS expression level, while K562 was natural resistant to L-asparaginase and possessed of the highest AsnS level. It is concluded that the AsnS plays a critical role in regulating cellular biological behavior after depletion of asparagine, the AsnS mRNA expression level in cells reflects the sensitivity of cells to L-Asp. The results may imply the possibility for the use of L-asparaginase in leukemia with lower AsnS expression level.
Asparaginase ; metabolism ; pharmacology ; Aspartate-Ammonia Ligase ; metabolism ; Cell Line, Tumor ; Humans ; Leukemia ; enzymology

OBJECTIVETo determine whether the high level of asparagine synthetase (AS) expression in childhood acute lymphocytic leukemia (ALL) is associated with an inferior prognosis.

METHODSAS mRNA level in leukemic cells from 53 newly diagnosed ALL children was measured by real time fluorescent quantitative PCR method. Patients were divided into groups according to their relapse risk and outcome, and the AS expression levels in each group were compared. The survival rates in different AS expressing level groups were estimated and compared.

RESULTSThe highest level of AS [median 17.25 (2.48-46. 82)] was observed in children failed remission, intermediate level [14.28 (3.20-54.47)] in relapsed children and the lowest level [5.08 (0.84-54.92)] in children with continuous complete remission (CCR) (P<0.05). The AS mRNA level [14.93 (2.48-54.47)] in children with poor outcome (un-remission and relapsed) was significantly higher than that in children in CCR (P<0.01). The two-year estimated disease free survival was much lower in children with high AS expression (53.8%) than in those with low AS expression (84.6%) (P<0.05).

CONCLUSIONHigh expression of AS is associated with a poor outcome in ALL children.

Adolescent ; Aspartate-Ammonia Ligase ; metabolism ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; enzymology ; Prognosis

High expression of cellular asparagine synthetase (AS) is a causative factor for the resistance of leukemic cell to L-asparaginase therapy. This study was aimed to find single nucleotide polymorphism (SNPs) in the promotor region of asparagine synthetase (AS) gene and to determine if these SNPs have influence on the transcriptional activity of AS promotor. The DNA sequences of AS promoter (pAS) from 82 leukemic children and 45 controls were determined to screen for SNPs in this region and the AS mRNA level in these samples was quantified using real-time PCR assay. The results indicated that three SNPs were found in the sequenced pAS fragment. They were -239C/T, -92G/A and -62A/T respectively. The frequency of -92A allele was higher in leukemic samples than that in nonleukemic control (P<0.05). The gene expression level differed among the individuals with genotype of the -92G/A SNP, and the descending order was as follows: GA heterozygote > AA homozygote > GG homozygote. It is concluded that some features in leukemia might associate with SNP on -92A locus, and this SNP in pAS can be one of the factors influencing transcriptional activity of AS gene. The existence of the -92A allele variant contributes to a high expression of AS gene.
Aspartate-Ammonia Ligase ; genetics ; Child ; Female ; Humans ; Leukemia, Myeloid, Acute ; enzymology ; genetics ; Male ; Polymorphism, Single Nucleotide ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; enzymology ; genetics ; Promoter Regions, Genetic ; genetics

OBJECTIVETo study the cellular activity of asparagine synthetase in different types of childhood acute lymphoblastic leukemia (ALL).

METHODSThe cellular activity of asparagine synthetase was detected by HPLC-FLD and Protein measurement in 28 ALL children (7 cases of T-ALL and 21 cases of B-lymphoid lineage ALL) before chemotherapy.

RESULTSThe asparagines synthetase activity levels in T-ALL children were significantly higher than those of the B-lymphoid lineage ALL patients, with the median activity level of 9.3 nM Asn/mg protein/hr vs 5.2 nM Asn/mg protein/hr (P < 0.05). The distribution of the asparagine synthetase activity demonstrated a polymorphism in either T-ALL or B-lymphoid lineage ALL patients.

CONCLUSIONSThe cellular activity of asparagines synthetase in ALL patients is presented with a polymorphism distribution. The asparagines synthetase activity levels in T-ALL are significantly higher than in B-lymphoid lineage ALL.

Asparaginase ; therapeutic use ; Aspartate-Ammonia Ligase ; genetics ; metabolism ; Child ; Core Binding Factor Alpha 2 Subunit ; genetics ; Female ; Humans ; Male ; Oncogene Proteins, Fusion ; genetics ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; drug therapy ; enzymology ; RNA, Messenger ; analysis