Extrinsic nitric oxide donor partially reverses arginine deiminase induced cell growth inhibition through NFκB and Bcl-XL

Abstract

Arginine deiminase (ADI) is known to be an inducer of apoptosis in vitro and an anti-tumor agent in vivo in some cancers. ADI causes the enzymatic depletion of arginine which may inhibit nitric oxide (NO) synthesis. However, the effect of ADI treatment on NO synthesis has not been clearly elucidated. With the goal of understanding the role of ADI in NO synthesis, we used the Ramos human lymphoma cell line, which is known to be ADI-sensitive. After determining an optimal experimental ADI concentration (0.001 U/ml), we studied the effects of ADI treatment when combined with different concentrations of the extrinsic NO donor, sodium nitroprusside (SNP) (i.e., control, ADI only, ADI with 10 microM/ml SNP, ADI with 50 microM/ml SNP, and ADI with 100 microM/ml SNP). An MTT assay was used to assess cell survival after treatment, nitric oxide assays to determine nitrite levels and Western blot analysis to determine the expression of the NO mediators, NFkappaB and Bcl-X L. Interestingly, we found that the extrinsic NO donor only partially reversed ADI-induced inhibition of cell growth in a dose-dependent pattern and resulted in an induction of NFkappaB and Bcl-X L expression. In conclusion, we suggest that there might be an association between reversal of cell growth inhibition by extrinsic NO donor with Bcl-X L and NFkappaB expression in ADI-treated Ramos cell.

NO/beta-catenin crosstalk modulates primitive streak formation prior to embryonic stem cell osteogenic differentiation

“…An indirect crosstalk could for example be possible through NO regulation of CatnB transcription. For example, NO is known to activate the transcription factors E2F1, NFKB, AP1, AP2, CREB, and SP1 (Sellak et al, 2002;Cui et al, 2005;Dhakshinamoorthy et al, 2007;Seo et al, 2008). When we bioinformatically examined the CatnB promoter for binding sites of these NOinduced transcription factors, we found that all of the mentioned transcription factors could potentially regulate CatnB mRNA expression, since all of these have binding sites on the CatnB promoter (Li et al, 2004).…”

Arginine deprivation and argininosuccinate synthetase expression in the treatment of cancer

“…These reactive species are critical to macrophage cytotoxicity and may play a role in the tumour microenvironment following arginine deprivation 70. In other cell models NO donors, such as sodium nitroprusside, only partly reverse the inhibitory effect of ADI in vitro 71. Third, alternative pathways involving proteins may be affected, such as the synthesis of arginine‐rich nuclear histones 72.…”

Arginine deiminase originating fromLactococcus lactisssp.lactisAmerican Type Culture Collection (ATCC) 7962 induces G1-phase cell-cycle arrest and apoptosis in SNU-1 stomach adenocarcinoma cells

“…Previous investigations of the mechanism underlying arginine depletion showed that it inhibited cyclin D 1 expression in human diploid fibroblasts ( 35 ) and induced p27 Kip1 and p21 Cip1 in HepG2 human hepatoma cells ( 36 ) . Also, MADI reportedly inhibits Bcl-xL in human lymphoma cells ( 37 ) . However, how arginine depletion inhibits c-myc expression remains to be elucidated.…”