We searched for metastasis-related genes in adenoid cystic carcinoma by suppression subtractive hybridization analysis of high and low metastasis cell lines. Twelve genes (ten previously identified and two novel sequences) were identified as being expressed at lower levels in high metastasis cell line Acc-M when compared to low metastasis cell line Acc-2. The known sequences corresponded to the genes for cysteine-rich angiogenesis induction factor (cyr61), chromosome 7 RP11-52501 clone, G-protein, WAS familial ferritin I heavy chain, jumping translocation breakpoint, eukaryotic translation elongation, folate receptor and three ribosomal proteins. Among them, the G protein and ferritin I heavy chain genes contained mutations in the high metastasis cell line. The two novel gene sequences have been named ACC metastasis-associated RNH and ACC metastasis-associated suspected protein (GenBank # AF522024 and AF522025, respectively). Taken together, these results suggest that reduced expression and/or mutation of several genes in the tumor cell line Acc-M are associated with high tumor metastasis, providing important molecular biological materials for further study of metastasis control and possible targets for cancer gene therapy.
Blotting, Northern ; Carcinoma, Adenoid Cystic/*genetics/secondary ; *Gene Expression ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Human ; In Vitro ; Molecular Sequence Data ; Neoplasm Metastasis/*genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Cells, Cultured

Glucosamine, a naturally occurring amino monosaccharide, has been reported to play a role in the regulation of apoptosis more than half century. However the effect of glucosamine on tumor cells and the involved molecular mechanisms have not been thoroughly investigated. Glucosamine enters the hexosamine biosynthetic pathway (HBP) downstream of the rate-limiting step catalyzed by the GFAT (glutamine:fluctose-6-phosphate amidotransferase), providing UDP-GlcNAc substrates for O-linked beta-N-acetylglucosamine (O-GlcNAc) protein modification. Considering that O-GlcNAc modification of proteasome subunits inhibits its activity, we examined whether glucosamine induces growth inhibition via affecting proteasomal activity. In the present study, we found glucosamine inhibited proteasomal activity and the proliferation of ALVA41 prostate cancer cells. The inhibition of proteasomal activity results in the accumulation of ubiquitinated proteins, followed by induction of apoptosis. In addition, we demonstrated that glucosamine downregulated proteasome activator PA28gamma and overexpression of PA28gamma rescued the proteasomal activity and growth inhibition mediated by glucosamine. We further demonstrated that inhibition of O-GlcNAc abrogated PA28gamma suppression induced by glucosamine. These findings suggest that glucosamine may inhibit growth of ALVA41 cancer cells through downregulation of PA28gamma and inhibition of proteasomal activity via O-GlcNAc modification.
Acetylglucosamine/chemistry/metabolism ; Alloxan/pharmacology ; Apoptosis/*drug effects ; Autoantigens/genetics/*metabolism ; Cell Line, Tumor ; Cell Proliferation/*drug effects ; Gene Expression Regulation, Neoplastic ; Glucosamine/*pharmacology ; Humans ; Male ; Phosphorylation ; Prostatic Neoplasms/*enzymology ; Proteasome Endopeptidase Complex/*antagonists & inhibitors/genetics/metabolism ; RNA, Small Interfering/genetics ; Ubiquitinated Proteins/metabolism

PURPOSE: Synuclein-gamma (SNCG), which was initially identified as breast cancer specific gene 1, is highly expressed in advanced breast cancers, but not in normal or benign breast tissue. This study aimed to evaluate the effects of SNCG siRNA-treatment on breast cancer cells and elucidate the associated mechanisms. METHODS: Vectors containing SNCG and negative control (NC) siRNAs were transfected into MDA-MB-231 cells; mRNA levels were determined by real-time polymerase chain reaction. Cell proliferation was evaluated using the MTT assay, cell migration was assessed by the Transwell assay, apoptosis and cell cycle analyses were conducted with the flow cytometer, and Western blot analysis was performed to determine the relative levels of AKT, ERK, p-AKT, and p-ERK expression. RESULTS: SNCG mRNA levels were significantly reduced in MDA-MB-231 cells transfected with SNCG siRNA. Our results indicate that in SNCG siRNA-treated cells, cell migration and proliferation decreased significantly, apoptosis was induced, and the cell cycle was arrested. Western blot analysis indicated that the protein levels of p-AKT and p-ERK were much lower in the SNCG siRNA-treated groups, than in the control and NC groups. CONCLUSION: SNCG siRNA could decrease the migration and proliferation of breast cancer cells by downregulating the phosphorylation of AKT and ERK.
Apoptosis ; Blotting, Western ; Breast ; Breast Neoplasms ; Cell Cycle ; Cell Migration Assays ; Cell Movement* ; Cell Proliferation ; Extracellular Signal-Regulated MAP Kinases ; Phosphorylation* ; Proto-Oncogene Proteins c-akt ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; RNA, Small Interfering ; Synucleins*