Hepatoma upregulated protein expression is involved in the pathogenesis of human breast carcinogenesis.

In the last decade, the overexpression of hepatoma upregulated protein (HURP) has been reported in hepatocellular carcinoma, adrenocortical tumors and urogenital carcinoma. However, the role of HURP in breast cancer remains unknown. In the present study, a comprehensive analysis was performed to examine the HURP expression level in 43 breast cancer tumor samples and paired adjacent normal tissues. The correlation between the HURP expression level and the clinicopathological characteristics was evaluated. The role of HURP in breast cancer was investigated by quantitative polymerase chain reaction, western blot analysis and cell proliferation assays. HURP expression was found to be significantly increased in the breast cancer samples. The HURP expression level was higher in the tumors with advanced-grade metastasis and was strongly associated with tumor-node-metastasis staging (P=0.003). Transfection and cell proliferation assays suggested that the suppression of HURP expression or the interference in HURP activity in the breast cancer cells inhibited cell proliferation significantly. These data suggest that HURP is associated with the degree of malignancy and the proliferation of breast cancer. HURP could be a tumor biomarker for prognosis and a potential therapeutic drug target for human breast cancer.

Promoter hypermethylation may be an important mechanism of the transcriptional inactivation of ARRDC3, GATA5, and ELP3 in invasive ductal breast carcinoma.

Hypermethylation of promoter CpG islands represents an alternative mechanism to inactivate tumor suppressor genes. This study was to detect promoter methylation status and mRNA expression levels of ARRDC3, ELP3, GATA5, and PAX6, and to explore the association between methylation and expression in invasive ductal carcinomas (IDCs) and matched normal tissues (MNTs) from breast cancer patients. Aberrant gene methylation was observed as follows: ARRDC3 in 38.5 %, ELP3 in 73.1 %, GATA5 in 48.1 %, and PAX6 in 50.0 % of IDCs. mRNA expression of ARRDC3, ELP3, and GATA5 in IDCs showed a lower level than that in MNTs (P < 0.001, P = 0.001 and P < 0.001, respectively). For ARRDC3, both methylated and unmethylated IDCs showed significantly lower expression values compared to MNTs (P = 0.001 and P = 0.007, respectively). For ELP3 and GATA5, methylated tumors only showed significantly lower expression values compared to MNTs (P = 0.001 and P < 0.001, respectively). For ARRDC3 and GATA5, methylation was associated with their less fold change in IDCs (P = 0.049 and P = 0.020, respectively). Methylation of ARRDC3 was significantly associated with grades and lymph node status of IDCs (P = 0.036 and P = 0.002, respectively). Methylation frequency of ELP3 was higher in lymph node positive versus lymph node negative tumors (P = 0.020); whereas methylation frequency of PAX6 was lower in tumors with the ER negative samples (P = 0.025). Our data suggested that promoter hypermethylation may be an important mechanism of the transcriptional inactivation of ARRDC3, GATA5, and ELP3 in IDCs.

[Two-dimensional electrophoresis analysis of hydrophobic membrane proteome in mouse hepatocarcinoma cell H22].

OBJECTIVE: To compare the membrane protein profile of mouse hepatocarcinoma cell H22 with that of normal liver cell. METHODS: The membrane proteins in mouse hepatocarcinoma cell H22 and normal liver cell were extracted and their concentrations were determined by Bradford method. The proteins were separated by two-dimensional electrophoresis, and then stained with silver. The 2-DE maps were scanned and analyzed by Image Master 2D Platinum software. The differential expression protein spots were cut out from the gels, and the peptide fingerprinting was determined by MALDI-TOF-MS (Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry), followed by matching to Swiss-Prot protein database by Aldente software with experimental pI and MW data. RESULTS: Compared to normal liver cells, 8 membrane proteins, including sulfatase-modifying factor 2, protein kinase C and casein kinase II substrate protein 3, sorting and assembly machinery component 50 homolog, macrophage scavenger receptor types I/II, uncharacterized protein C9 or f135 homolog, tight junction protein ZO-2, 3-hydroxy-3- methylglutaryl-coenzyme A reductase, and vacuolar protein sorting-associated protein 52 homolog were upregulated in H22 cells. CONCLUSION: The membrane proteins involved in cell metabolism, proliferation, signal transduction, and skeleton, which are highly expressed in mouse hepatocarcinoma H22 cells, are probably related to the proliferation, invasion and migration of this tumor cell line.