The Significance of VSIG4 Expression in Ovarian Cancer.

OBJECTIVES: The protein V-set and Ig domain-containing 4 (VSIG4), a novel B7 family-related macrophage protein with the capacity to inhibit T-cell activation, has a potential role in cancer. Here we suggest its possibility as a therapeutic target and prognostic biomarker of ovarian cancer. METHODS: Between January 2011 and June 2015, tumor tissues and peripheral blood samples were obtained during surgery from 10 patients with benign ovarian tumors and 22 patients with ovarian cancers. Messenger RNA and protein expression levels of VSIG4 in benign tumor and cancer tissues were examined by the reverse transcription polymerase chain reaction and Western blot, respectively. Soluble VSIG4 concentrations were measured by an enzyme-linked immunosorbent assay. The correlation between VSIG4 expression and the prognosis of ovarian cancer was analyzed according to the patients' clinicopathologic characteristics. RESULTS: VSIG4 messenger RNA and protein expression levels in ovarian cancer tissues were higher than those in benign ovarian tumors (P = 0.0013 and 0.0001, respectively). Soluble VSIG4 concentrations were increased in patients with ovarian cancer compared with that in patients with benign ovarian tumors (P = 0.0452). Moreover, soluble VSIG4 levels were significantly increased in advanced-stage and recurrent ovarian cancer (P = 0.0244 and 0.0288, respectively). High VSIG4 expression of cancer tissue and low VSIG4 expression of plasma (soluble VSIG4) were associated with a longer disease-free interval (P = 0.0246 and 0.0398, respectively). CONCLUSIONS: VSIG4 is overexpressed in ovarian cancers compared with that in benign tumors. This finding supports VSIG4 being used as a potential therapeutic target for ovarian cancer. Furthermore, soluble VSIG4 levels are associated with the progression and recurrence of ovarian cancer, indicating that soluble VSIG4 may be used as a potential biomarker for predicting tumor prognosis.

Establishment and characterization of seven human breast cancer cell lines including two triple-negative cell lines.

Permanently growing cell lines can be invaluable because of their usefulness in a variety of experimental situations. We report the characteristics of seven cell lines designated, SNU-306, SNU-334, SNU-1528, SNU-1553, SNU-1581, SNU-1958 and SNU-2372, which were established from three primary carcinomas, two pleural effusion, one pericardial effusion and one ascitic fluid samples obtained from seven Korean breast carcinoma patients. The histopathology of the primary tumors and their in vitro growth characteristics are described. DNA fingerprinting analysis and genetic alterations in the p53 and EGFR genes were conducted. The expression levels of the ER-α, PR, C-erbB2, E-cadherin, COX-2, MDR and MXR genes were investigated and sensitivity to anticancer drugs was screened. Growth was as adherent cells (four cell lines), floating aggregates (one cell line) and both (two cell lines). All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis using 18 microsatellite markers. Estrogen receptor (ER) mRNA was highly expressed in five cell lines and low or undetectable in SNU-1958 and SNU-2372. Progesterone receptor (PR) mRNA was expressed only in the SNU-306. SNU-1958 and SNU-2372 were hormone receptor-negative and C-erbB2-negative (triple-negative). SNU-1528 had an in-frame deletion of 42 base pairs of p53 gene and showed over 20-fold resistance for taxol compared to the other cell lines. There were no mutation in the EGFR gene; COX-2 was expressed in four cell lines and MXR was expressed in two cell lines. These well-characterized seven breast cancer cell lines, which include two triple-negative cell lines, will be useful for the study of breast cancer biology.

Methylation-specific PCR.

DNA methylation patterns in CpG-rich regions of promoter, CpG islands, are concerned in regulation of gene expression in mammalian cells. Excessive methylation of CpG dinucleotides in promoter represses the gene expression. In cancer, especially, gene silencing is occurred through aberrant methylation in promoter of tumor suppressor genes. Methylation-specific PCR (MSP) is a method for analysis of DNA methylation patterns in CpG islands. For performing MSP, DNA is modified by and PCR performed with two primer pairs, which are detectable methylated and unmethylated DNA, respectively. MSP is a rapid measure for assession of the methylation status in CpG island.

Establishment and characterization of six human lung cancer cell lines: EGFR, p53 gene mutations and expressions of drug sensitivity genes.

BACKGROUND: Six human lung cancer cell lines (SNU-371, SNU-963, SNU-1327, SNU-1330, SNU-2292 and SNU-2315) were newly established through primary cell cultures. These cell lines were derived from a pulmonary blastoma, a small cell lung cancer, three adenocarcinomas and a squamous cell carcinoma of the lung of six Korean lung cancer patients. METHODS: The histopathology of the primary tumors and their in vitro growth characteristics were described. DNA fingerprinting analysis and genetic alterations in the p53, ß-catenin, TGFßRII, K-ras and EGFR genes were conducted. mRNA expressions levels of E-cadherin, COX-2, MDR1, MXR, CGA, synatophysin and TTF1 genes were investigated and sensitivity to anticancer drugs was screened. RESULTS: Five cell lines grew as adherent cells and one cell line grew as floating aggregates. All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis. A significant polymorphism at codon 72 (Arg to Pro) of the p53 gene was found in one line (SNU-1327) and a mutation at codon 176 was found in SNU-2292. No mutations in the K-ras, ß-catenin and TGF-ßRII genes were observed. E-cadherin was not expressed in SNU-371 and COX-2 was overexpressed in SNU-1330, SNU-2292 and SNU-2315 cell lines. MDR1 was overexpressed in SNU-371 and SNU-2292 cell lines and MXR was overexpressed in SNU-1327 cell line. Interestingly, the SNU-371 cell line derived from a pulmonary blastoma and which overexpressed MDR1 displayed cross resistance for several anticancer drugs. Neuroendocrine markers, chromogranin A and synaptophysin, were overexpressed in the small cell lung cancer cell line, SNU-963 and thyroid transcription factor-1 was also over expressed in this cell line. Two mutations (p.Glu746_Ser752delinsVal and p.Glu746_Ala750del) in exon 19 of EGFR were found in SNU-1330 and SNU-2315 cell lines, respectively. CONCLUSION: These well-characterized lung cancer cell lines may be useful tools for investigations of the biological characteristics of lung cancers, particularly for investigations related to mutations of EGFR.

Promoter hypermethylation and loss of CD133 gene expression in colorectal cancers.

AIM: To understand CD133 promoter hypermethylation and expression in 32 colorectal cancer cell lines. METHODS: Nucleic acid was isolated from 32 colorectal cancer cell lines and CD133 expression levels were measured by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR. Promoter methylation status of the CD133 gene was analyzed with a methylation-specific PCR after sodium-bisulfite modification and by clonal sequencing analysis. The correlation between expression and promoter methylation of CD133 gene was confirmed with treatment of 5-aza-2'-deoxycytidine. RESULTS: We measured CD133 expression levels in 32 colorectal cancer cell lines. RT-PCR analysis showed undetectable or low levels of CD133 expression in 34.4% of cell lines. To verify the relation between CD133 expression and methylation status of the CD133 gene promoter in colorectal carcinogenesis, CD133 gene promoter hypermethylation was analyzed in 32 cancer cell lines. Promoter hypermethylation was detected in 13 (40.6%) of the cell lines using methylation specific-PCR and confirmed by bisulfite sequencing analysis. Treatment of 11 of the cell lines with the demethylation agent 5-aza-2'-deoxycytidine recovered CD133 expression in most of them. CONCLUSION: Transcriptional repression of CD133 is caused by promoter hypermethylation of the CD133 CpG islands in some of colorectal cancer cell lines. The study may contribute to the understanding of the role of CD133 inactivation in the progression of colorectal cancers.

Establishment and characterization of 13 human colorectal carcinoma cell lines: mutations of genes and expressions of drug-sensitivity genes and cancer stem cell markers.

Thirteen human colorectal cancer (CRC) cell lines were established from 10 primary tumors and 3 metastatic tumors obtained from 13 Korean patients. Characteristics of the cell lines including morphology in vivo and in vitro; mutations of the K-ras, p53, APC and MMR genes and microsatellite instability (MSI) status in vitro were determined. Expression of drug-sensitivity genes including MDR1, MXR, MRP1 and COX2 was also analyzed. The cell lines were unique as judged by DNA fingerprinting using 16 short tandem repeats. Eleven of the cell lines grew as adherent populations and the remaining two as floating aggregates. None of the cell lines were contaminated with Mycoplasma or bacteria. All cell lines showed high viability with relatively long doubling times. Six cell lines contained mutations at K-ras. Seven cell lines displayed p53 gene missense, nonsense and frameshift mutations. MSI was found in three cell lines and two cell lines with an MSI-high phenotype-possessed hMLH1 mutations. Nine cell lines had an APC mutation. MRP1 was highly expressed in all cell lines, and high expression of MDR1, MXR and COX2 evident in eight, six and six cell lines, respectively. Embryonal stem cell markers (MELK, SOX4 and OCT4) were expressed in most of cell lines. The cancer stem cell biomarkers CD133, CD44 and Lgr5 were expressed in 12, 13 and 13 cell lines, respectively. The presently well-characterized CRC cell lines should be useful in investigations of the biological characteristics of CRC, particularly for investigations related to gene alterations associated with CRC and biology of cancer stem cells.

Promoter hypermethylation of the ADAM23 gene in colorectal cancer cell lines and cancer tissues.

Promoter hypermethylation of the ADAM23 gene, which is normally involved in cell-to-cell and cell-to matrix adhesion, has been reported in pancreatic, breast and brain cancer, and recently the role of this gene was examined in gastric cancer. In this study, we analyzed ADAM23 expression in colorectal cancer cell lines and examined its methylation by methylation-specific PCR (MSP) and bisulfate-modified DNA sequencing analysis. Methylated cells were treated with 5-aza-2'-deoxycytidine to restore the ADAM23 expression. We then examined ADAM23 methylation status in colorectal cancer tissues and their corresponding normal tissues. We found that ADAM23 was aberrantly silenced or expressed at very low levels in 28 of the 32 (88%) colorectal cancer cell lines. MSP analysis showed that ADAM23 was methylated in 29 of 32 (91%) colorectal cancer cell lines and attenuated expression of ADAM23 was found to be related to hypermethylation in its promoter region. Moreover, the CpG dinucleotide methylation threshold of 70-90% was found to be required for complete silencing. In addition, when some cell lines without ADAM23 expression were treated with 5-aza-2'-deoxycytidine, ADAM23 was reexpressed. In colorectal cancer tissues, the promoter region of ADAM23 was hypermethylated in 36 of 76 (47%). These results demonstrated that ADAM23 may be down-regulated by aberrant promoter hypermethylation during the progression of colorectal cancer.