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Sperm Specific antigen 2 (SSFA2) is a novel p53 target gene
Sujan Piya,Kim, Tae-Hyoung 朝鮮大學校 附設 醫學硏究所 2009 The Medical Journal of Chosun University Vol.33 No.S
The master watchman p53 well-known as a tumor suppressor modulates the cell cycle arrest, senescence, and apoptosis through the transcriptional regulation of its target genes. A number of the p53-induced genes were scrutinized by DNA chip analysis to understand the pros and cons of p53-exerted multiple phenomena and their roles in the tumor suppression. Here, we have identified sperm specific antigen 2 (SSFA2) gene upregulated by ectopic over-expression of p53 in HCT116 cells. 5FU-treated HCT116 cells showed the increased levels of SSFA2, indicating that endogenous p53 is able to transactivate SSFA2 gene. Moreover, introduction of short hairpin RNA for SSFA2 into HCT116 cells showed the slight reduction of the levels of cell death induced by 5FU, Etoposide, and TRAIL. These findings suggest that SSFA2 appears to play a minor role in the p53-mediated apoptosis.
The Effect of Lipopolysaccharide on Noxa Expression Is Mediated through IRF1, 3, and 7
( Sujan Piya ),( Tae-hyoung Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.3
Lipopolysaccharide (LPS), a component of the cell wall of gram-negative bacteria, elicits the secretion of cytokines, such as interferons, that stimulate the host defense system. Previously, we demonstrated that interferons induce interferon regulatory factors (IRFs) 1, 3, and 7, which regulate the transcription of Noxa and alter the expression profiles of Bcl-2 family proteins in tumors. However, the immediate consequences of LPS stimulation on Noxa and BH3 expression in tumor cells remain uncharacterized. In this study, we determined that LPS induced Noxa expression in CT26 cells. Furthermore, studies in HCT116 parental and HCT116 p53-deficient cells revealed that LPS-mediated Noxa was independent of p53. Meanwhile, IRF1, 3, and 7 in CT26, HCT116 parental, and HT116 p53-deficient cells were upregulated by LPS stimulation, suggesting that LPS induces the expression of these IRFs in a p53- independent manner. The responsiveness of IRF1, 3, 4, and 7 binding to the Noxa promoter region to LPS indicated that IRF1, 3, and 7 activated Noxa expression, whereas IRF4 repressed Noxa expression. Together, these results suggest that LPS directly affects Noxa expression in tumor cells through IRFs, implicating that it may contribute to LPS-induced tumor regression.
Piya, Sujan,Moon, Ae Ran,Song, Peter I,Hiscott, John,Lin, Rongtuan,Seol, Dai-Wu,Kim, Tae-Hyoung American Association for Cancer Research 2011 Molecular cancer research Vol.9 No.10
<P>IFN-gamma plays a critical role in tumor immunosurveillance by affecting either immune cells or tumor cells; however, IFN-mediated effects on tumor elimination are largely unknown. In this study, we showed that IFN regulatory factors (IRF) modulated by IFNs up- and downregulated Noxa expression, a prodeath BH3 protein, in various cancer cells. Inhibition of Noxa expression using short hairpin RNA in tumor cells leads to resistance against lipopolysaccharide (LPS)-induced tumor elimination, in which IFN-gamma is known as a critical effecter in mice. Chromatin immunoprecipitation analysis in both CT26 cells and SP2/0 cells, sensitive and resistant to LPS-induced tumor elimination, respectively, revealed that the responsiveness of IRF1, 3, 4, and 7 in the Noxa promoter region in response to IFN-gamma might be crucial in LPS-induced tumor elimination. IRF1, 3, and 7 were upregulated by IFN-gamma and activated Noxa expression, leading to the death of Noxa wild-type baby mouse kidney (BMK) cells but not of Noxa-deficient BMK cells. In contrast, IRF4 acts as a repressor for Noxa expression and inhibits cell death induced by IRF1, 3, or 7. Therefore, although IFN-gamma alone are not able to induce cell death in tumor cells in vitro, Noxa induction by IFN-gamma, which is regulated by the balance between its activators (IRF1, 3, and 7) and its repressor (IRF4), is crucial to increasing the susceptibility of tumor cells to immune cell-mediated cytotoxicity. Mol Cancer Res; 9(10); 1356-65. (C) 2011 AACR.</P>
TRAIL-induced cell death and caspase-8 activation are inhibited by cisplatin but not carboplatin
한세준,안태규,최한송,신진나,Sujan Piya,김태형 대한부인종양학회 2009 Journal of Gynecologic Oncology Vol.20 No.2
Objective: Platinum (Pt) based drugs including cisplatin and carboplatin are widely used as anticancer drugs in various human cancers. Many studies have shown that chemotherapeutic agents synergistically enhance cell death induced by death ligands. However it has been recently reported that cisplatin may inhibit tumor necrosis factorrelated apoptosis-inducing ligand (TRAIL)-induced cell death through inactivation of caspases. Thus, we investigated whether carboplatin also inhibits TRAIL-induced cell death. Methods: HeLa cells were treated with TRAIL in the presence of cisplatin or carboplatin, and cell death was analyzed using the crystal violet staining method. Caspase activation was checked through detection of Bid cleavage by Western blotting using anti-Bid antibody. Results: Cisplatin inhibits TRAIL-induced cell death in HeLa cells; however, carboplatin enhanced TRAIL-induced cell death. Whereas cisplatin inhibited caspase-8-mediated Bid cleavage, carboplatin had no effect on caspase-8 activity. Conclusion: Although cisplatin and carboplatin are platinum-containing cancer therapeutic agents, they have the opposite effects on TRAIL-induced cell death. Objective: Platinum (Pt) based drugs including cisplatin and carboplatin are widely used as anticancer drugs in various human cancers. Many studies have shown that chemotherapeutic agents synergistically enhance cell death induced by death ligands. However it has been recently reported that cisplatin may inhibit tumor necrosis factorrelated apoptosis-inducing ligand (TRAIL)-induced cell death through inactivation of caspases. Thus, we investigated whether carboplatin also inhibits TRAIL-induced cell death. Methods: HeLa cells were treated with TRAIL in the presence of cisplatin or carboplatin, and cell death was analyzed using the crystal violet staining method. Caspase activation was checked through detection of Bid cleavage by Western blotting using anti-Bid antibody. Results: Cisplatin inhibits TRAIL-induced cell death in HeLa cells; however, carboplatin enhanced TRAIL-induced cell death. Whereas cisplatin inhibited caspase-8-mediated Bid cleavage, carboplatin had no effect on caspase-8 activity. Conclusion: Although cisplatin and carboplatin are platinum-containing cancer therapeutic agents, they have the opposite effects on TRAIL-induced cell death.