Hwa-Li Kao

Mitochondrial dysfunction promotes cell migration via reactive oxygen species-enhanced β5-integrin expression in human gastric cancer SC-M1 cells.

BACKGROUND Mitochondrial dysfunction has been shown to promote cancer cell migration. However, molecular mechanism by which mitochondrial dysfunction enhances gastric cancer (GC) cell migration remains unclear. METHODS Mitochondria specific inhibitors, oligomycin and antimycin A, were used to induce mitochondrial dysfunction and to enhance cell migration of human gastric cancer SC-M1 cells. Antioxidant N-acetylcysteine (NAC) was used for evaluating the effect of reactive oxygen species (ROS). Protein expressions of epithelial-to-mesenchymal transition (EMT) markers and the cell-extracellular matrix (ECM) adhesion molecules, the integrin family, were analyzed. A migratory subpopulation of SC-M1 cells (SC-M1-3rd) was selected using a transwell assay for examining the association of mitochondrial bioenergetic function, intracellular ROS content and β5-integrin expression. Clinicopathologic characteristics of β5-integrin expression were analyzed in GC specimens by immunohistochemical staining. RESULTS Treatments with mitochondrial inhibitors elevated mitochondria-generated ROS and cell migration of SC-M1 cells. The protein expression of β5-integrin and cell surface expression of αvβ5-integrin were upregulated, and which were suppressed by NAC. Pretreatments with NAC and anti-αvβ5-integrin neutralizing antibody respectively prevented the mitochondrial dysfunction-induced cell migration. The selected migratory SC-M1-3rd cells showed impaired mitochondrial function, higher mitochondria-generated ROS, and increased β5-integrin expression. The migration ability was also repressed by anti-αvβ5-integrin neutralizing antibody. In clinical specimens, GCs with higher β5-integrin protein expression had more aggressive behavior. In conclusion, mitochondrial dysfunction may lead to GC progression by enhancing migration through mitochondria-generated ROS mediated β5-integrin expression. GENERAL SIGNIFICANCE These results support the role of mitochondrial dysfunction in GC progression.

Glucocorticoid receptors in hepatocellular carcinoma and adjacent liver tissue

Glucocorticoid and progesterone receptors, tyrosine aminotransferase, gamma‐glutamyltransferase and alpha‐fetoprotein levels were determined in human hepatocellular carcinoma (HCC) and adjacent liver tissues. Glucocorticoid receptor was present in seven often HCC samples, values ranged from 1.9 to 66.8 fmol/mg protein. Progesterone receptor was present in two of ten HCC samples with values of 1.7 and 7.2 fmol/mg protein, respectively. In the adjacent liver tissues, no measurable progesterone receptor was found and only one sample had glucocorticoid receptor with a value of 3.0 fmol/mg protein. The increase of glucocorticoid receptor in HCC samples was coincident with a decreased level of tyrosine aminotransferase and an increased level of gamma‐glutamyltransferase. No correlation was found among glucocorticoid receptor level, serum or tissue alpha‐fetoprotein levels. The presence of glucocorticoid receptors in HCC suggest that hormones may play an important role in the formation of hepatoma, and hormonal therapy may be useful for patients with HCC.

The nontransformed progesterone and estrogen receptors in gastric cancer

Contents of the progesterone receptors (PgR) and estrogen receptors (ER) in 18 gastric adenocarcinoma tissues were determined using both the dextran-coated charcoal (DCC) assay and enzyme immunoassay (EIA). PgR were found in 15 cancer tissues (range, 1.0-58.8 fmol/mg protein) and 12 normal mucosal tissues (range, 1.4-26.8 fmol/mg protein) by DCC assay, whereas only 6 cancer tissues (ranged, 0.2-3.3 fmol/mg protein) and 7 normal mucosal tissues (range, 0.1-0.8 fmol/mg protein) had measurable PgR by EIA analysis. Similar results were observed for ER. DCC assay found ER in 12 cancer tissues (range, 2.9-112.6 fmol/mg protein) and 12 normal mucosal tissues (range, 1.2-36.6 fmol/mg protein), whereas EIA measured ER in 16 cancer tissues (range, 0.1-3.5 fmol/mg protein) and 15 normal mucosal tissues (range, 0.1-4.8 fmol/mg protein). No significant correlation between DCC and EIA was observed for either PgR or ER. DCC assay and its modified procedures including 5% DCC stripping of cytosol and/or the addition of sodium molybdate in buffer were simultaneously measured in 5 gastric adenocarcinoma tissues and 1 gastritis cystica polyposa tissue (a precancerous lesion). Higher receptor levels were found by the modified procedures than by conventional method. Using the DCC procedure with addition of sodium molybdate in buffer for receptor analysis, PgR and ER were found in gastric tissues in six patients, with significantly increased levels of measurable PgR. The results suggest that PgR and ER may be involved in the physiology of normal and gastric cancer tissues; their clinical implications are worthy of further study.

Class I and class II major histocompatibility complex antigens expression on human hepatocytes and hepatoma cells: an approach with high sensitivity and specificity.

The expression of gene products of the major histocompatibility complex (MHC) on the cell surface is known to play an important role in immunological responses. While some studies have reported the presence of MHC antigens on hepatocytes, information about specific, sensitive hepatocyte MHC antigen expression in various liver diseases is minimal. To investigate the expression of class I and class II MHC antigens on hepatocellular carcinoma (HCC) specimens, two-color flow cytometry was used to demonstrate MHC antigen expression on non-malignant and malignant hepatocytes using the hepatocyte-specific monoclonal antibody (MAb) 9B2 for selective gating and either MHC-specific W6/32 (class I) or Q5/13 (class II) MAb for MHC antigen detection. Non-malignant liver tissues demonstrated variable MHC antigen expression. Malignant hepatocytes isolated from resected HCC specimens as well as non-tumorous hepatocytes from these HCC specimens also disclosed various degrees of MHC antigen expression. Although we were not able to demonstrate a clear correlation between clinical outcome and MHC antigen expression in HCC, we conclude that the expression of MHC antigens on human hepatocytes and hepatoma cells can be accurately detected by flow cytometry using hepatocyte-specific MAb for selective gating and MHC-specific MAbs. Of note, two cases of non-malignant fetal liver tissues indicated that >95% of fetal hepatocytes expressed class I MHC antigens and <25% of fetal hepatocytes expressed class II MHC antigens. These findings may lead to further investigations into the progression of HCC cells or into the possible mechanisms of the hepatocellular carcinogenesis.

Advanced gastric cancer patients with lymphoid stroma have better survival than those without.

Lymphoid stroma is a specific pathologic appearance in gastric cancer. This study aims to compare the clinicopathological characteristics of gastric cancer patients with and without lymphoid stroma.