BACKGROUND: The expression of c-FLIP (cellular Fas-associated death domain-like interleukin-1 beta-converting enzyme (FLICE)-inhibitory protein), which is a member of the family of inhibitors of apoptosis, has been associated with tumor development and progression. The aim of this study was to evaluate the expression of c-FLIP in gastric cancer and its correlation with tumor cell proliferation, apoptosis and the clinicopathologic features. METHDOS: Immunohistochemical staining with anti-c-FLIP antibody was performed in 98 tissue samples obtained from gastric cancer patients who underwent surgical treatment. The apoptotic cells were visualized by terminal deoxynucleotidyl transferase (TdT) mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL), and the proliferative cells were visualized by staining with Ki-67 antibody. RESULTS: The positive expression of c-FLIP in the gastric cancer tissues was demonstrated in 57.1% of the cases. The expression of c-FLIP was increased in the gastric cancer tissues compared with the matched normal gastric mucosa. The expression of c-FLIP was significantly associated with histologic differentiation (p=0.038). However, there was no association between the c-FLIP expression and the other clinicopathological parameters, including patient survival. The Ki-67 labeling index (KI) for the 98 tumors ranged from 7.6 to 85.0 with a mean KI of 50.4+/-15.7. The mean KI value of the c-FLIP positive tumors was 54.1+/-15.3 and this was significantly higher than that of the c-FLIP negative tumors (p=0.005). The apoptotic index (AI) for the 98 tumors ranged from 0.0 to 10.0 with a mean AI of 7.4+/-2.3. There was no significant difference between the c-FLIP expression and the AI (p=0.347). CONCLUSIONS: These results suggest that the c-FLIP expression may be associated with tumor cell proliferation of gastric cancer.
Aged ; *Apoptosis ; CASP8 and FADD-Like Apoptosis Regulating Protein/*genetics ; *Cell Proliferation ; Disease Progression ; Female ; Health Status Indicators ; Humans ; Immunohistochemistry ; Ki-67 Antigen ; Male ; Middle Aged ; Pilot Projects ; Stomach Neoplasms/*genetics/pathology/physiopathology

OBJECTIVETo evaluate the relationship between mammalian target of rapamycin (mTOR) signaling pathway and histone acetylation in cell survival, cell cycle, gene expression and protein level on human gastric cancer cells.

METHODSHuman gastric cancer cell lines, MKN45 and SGC7901 were treated with trichostatin A, rapamycin and/or LY294002, a PI3K inhibitor. Cell viability was analyzed by methylthiazolyl tetrazolium. Cell cycle distribution was evaluated by flow cytometry. The transcription level of p21(WAF1) gene was detected by using real-time polymerase chain reaction. Proteins were detected by Western blotting.

RESULTSCell viability remarkably reduced after treatment by more than two drugs (P< 0.01). Through flow cytometry assessment, MKN45 cells were arrested in G2 phase (P< 0.05), while SGC7901 cells were in G2 or G1 phase (P< 0.05) whether treated with single or more than two drugs. The expression of p21(WAF1) mRNA was remarkably increased in the gastric cancer cells treated with conjoined drugs (P< 0.01). Phosphorylation of Akt, p70S6K and 4E-BP1 was significantly reduced in cells treated with conjoined drugs (P< 0.01). And histone acetylation of H4/H3 was also increased in cells treated with conjoined drugs (P< 0.01).

CONCLUSIONmTOR singnaling pathway has an important relationship with histone acetylation in gastric cancer cell lines. There is a co-effect of mTOR inhibitor and histone deacetylase inhibitor on gastric cancer cells.

Acetylation ; drug effects ; Adaptor Proteins, Signal Transducing ; metabolism ; Blotting, Western ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Survival ; drug effects ; Chromones ; pharmacology ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; Flow Cytometry ; Histones ; metabolism ; Humans ; Hydroxamic Acids ; pharmacology ; Morpholines ; pharmacology ; Phosphoproteins ; metabolism ; Phosphorylation ; drug effects ; Polymerase Chain Reaction ; Protein Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Ribosomal Protein S6 Kinases, 70-kDa ; metabolism ; Signal Transduction ; drug effects ; physiology ; Sirolimus ; pharmacology ; Stomach Neoplasms ; metabolism ; pathology ; physiopathology ; TOR Serine-Threonine Kinases