Functional significance of transgelin-2 in uterine cervical squamous cell carcinoma.

AIM: Transgelin-2 (TAGLN2) has previously been found to be highly expressed in uterine cervical squamous cell carcinoma (SCC) tissues by proteomic analyses. The present study investigated the role of TAGLN2 in the malignant behaviors of cervical SCC cells in vitro and in vivo, and the clinical significance of TAGLN2 using immunohistochemistry for human cervical SCC tissues. METHODS: Antisense (AS) constructs of TAGLN2 cDNA (AS clones) and the empty vector (control clone) were transfected into a human uterine SCC cell line (SKG IIIa), and malignant behaviors were analyzed in vitro. In an in vivo experiment, 10(7) cells of the AS and control clones were subcutaneously inoculated into female BALB/c nude mice. In immunohistochemistry with anti-TAGLN2 antibodies for human cervical SCC, FIGO stage IA and IB (n = 75), the expression patterns of TAGLN2 were divided into two groups: weak and strong. The relation between expression pattern and prognosis was analyzed. RESULTS: Suppression of TAGLN2 inhibited cancer cell migration and secretion of matrix metalloproteinases. Tumors in the control clone group continued to grow, whereas those in the AS clone group clearly stopped growing. Six weeks after injection, the tumor size was significantly smaller in the AS clone group than in the control clone group. Immunohistochemistry revealed that the strong pattern was associated with poor overall survival compared with the weak pattern by the Kaplan-Meier method. CONCLUSION: TAGLN2 plays functional roles in the progression of cervical SCC. Suppression of TAGLN2 may be a new strategy for the treatment of cervical SCC.

Heat shock protein 70 is involved in malignant behaviors and chemosensitivities to cisplatin in cervical squamous cell carcinoma cells.

AIM: Heat shock protein 70 (HSP70) was previously found to be highly expressed in cervical squamous cell carcinoma (SCC) tissues compared with normal tissues by proteomic analyses. The present study investigated the roles of HSP70 in malignant behaviors and chemosensitivity to cisplatin in cervical SCC cells in vitro. METHODS: Effects of HSP70 knockdown on activities of cell migration, cell invasion and cell proliferation, cell cycle status, and apoptosis were examined using siRNA in two human cervical cancer cells (SiHa and SKG II). Furthermore, the effect of HSP70 knockdown on the apoptotic effect by cisplatin was examined. RESULTS: HSP70 knockdown significantly suppressed activities of cell migration, cell invasion and cell proliferation. The cell cycle was arrested at the S- and G2/M-phases with the increase in apoptosis by HSP70 knockdown. Although cisplatin had no apoptotic effect in the control cell, it showed a dose-dependent apoptotic effect in the HSP70 knockdown cells in SiHa. In SKG II, 5 µg/mL of cisplatin induced apoptosis, and the apoptotic effect by cisplatin was enhanced by HSP70 knockdown. CONCLUSION: It was suggested that HSP70 played functional roles in the progression of uterine cervical SCC, and HSP70 knockdown enhanced chemosensitivities to cisplatin in cervical SCC cells.

Decreased carbonyl reductase 1 expression promotes malignant behaviours by induction of epithelial mesenchymal transition and its clinical significance.

Human carbonyl reductase 1 (CBR1) is an enzyme that catalyse the reduction of many compounds by using NADPH-dependent oxydoreductase activity. Although CBR1 is known to regulate the tumour progression, the molecular mechanisms of CBR1 in cancer progression and the clinical significance of CBR1 status remain unclear. Here, we investigated the molecular mechanisms by which CBR1 affects cancer cell behaviour in vitro and the clinical significance of CBR1 using immunohistochemical analyses in endometrial cancer. Here, the role of CBR1 in cancer cell invasion and metastasis, and its molecular mechanisms were investigated by transfection of sense and antisense CBR1 cDNAs into a human endometrial adenocarcinoma cell line. The relationship between CBR1 expression analysed by immunohistochemistry and prognosis such as progression free survival (PFS) and overall survival (OS) was examined in endometrial cancer tissues from FIGO stage I-IV (n=109). Suppression of CBR1 by antisense CBR1 cDNA increased cancer cell invasion, and suppressed E-cadherin expression and capacity for cellular aggregation. In contrast, over-expression of CBR1 by sense CBR1 cDNA increased E-cadherin expression and capacity for cellular aggregation, and suppressed cancer cell invasion. The expression of transcriptional suppressors of E-cadherin, Snail and ZEB1, were increased by CBR1 suppression, but suppressed by CBR1 over-expression. Immunohistochemical analyses showed that decreased CBR1 expression is significantly related with poor PFS and OS compared with strong CBR1 expression. In multivariate analyses, decreased CBR1 expression was an independent prognostic factor for PFS and OS. CBR1 regulates cancer cell invasion in endometrial adenocarcinomas by regulating the epithelial mesenchymal transition. A decreased CBR1 expression can be a useful marker of an unfavourable clinical outcome in patients with endometrial cancer.

Suppression of carbonyl reductase expression enhances malignant behaviour in uterine cervical squamous cell carcinoma: carbonyl reductase predicts prognosis and lymph node metastasis.

Carbonyl reductase (CR) is an NADPH-dependent, mostly monomeric, cytosolic enzyme with broad substrate specificity for carbonyl compounds. CR appears to be involved in the regulation of tumour progression. However, molecular mechanisms of CR in tumour progression and clinical significance of CR status remain unclear in human uterine squamous cell carcinoma (SCC). Here, we investigated the clinical significance of CR using immunohistochemical analyses of human uterine cervical SCC tissues and how CR affects cancer cell behaviour in vitro. Paraffin sections from uterine cervical SCC tissues, FIGO stage Ib1-IIb (n = 67) were immunostained with anti-CR antibodies. Overall survival (OS) and progression-free survival (PFS) were analyzed by the Kaplan-Meier method. Sense and antisense CR cDNAs were transfected into a human uterine SCC cell line (SiHa) to investigate the role of CR in cancer cell invasion and metastasis. Immunohistochemical analyses showed that reduced CR expression patterns in primary cancer lesions were closely associated with a high incidence of pelvic lymph node metastasis, poor OS, and poor PFS. In an in vitro experiment, suppression of CR increased cancer cell invasion, secretion of MMP-2, -9 and cyclooxygenase-2 (COX-2) expression and decreased E-cadherin expression. On the other hand, over-expression of CR increased E-cadherin expression and decreased MMP-2, -9 secretion and COX-2 expression. The reduced CR expression pattern, as measured by immunohistochemistry, can be a useful predictor of lymph node metastasis and poor prognosis in patients with uterine SCC. This clinical result is supported by the in vitro data which show that suppression of CR expression promotes cancer cell invasion with decreased E-cadherin expression and increased MMP-2, -9 secretion.

Comparative proteomic profiling in squamous cell carcinoma of the uterine cervix.

PURPOSE: Proteomic profiling of human uterine cervical squamous cell carcinoma (SCC) tissues was performed to find new biomarkers for the early diagnosis and molecular target therapies. EXPERIMENTAL DESIGN: Proteins extracted from five of normal tissues and five of the SCC tissues were subjected to 2-DE followed by LC-MS/MS. RESULTS: Twenty-seven of the protein spots were increased, and five of them were identified by LC-MS/MS to be cytokeratin-19, HSP70, HSP27, glyceraldehyde-3-phosphate dehydrogenase, and transgellin-2. The upregulation of HSP70, HSP27, and transgelin-2 was examined by Western blot of cultured SCC cell lines, ten additional normal tissues, ten additional SCC tissues, and three paired samples of the SCC tissue and its corresponding noncancerous tissue. The positive rate of HSP70 expression was higher in the SCC tissues than in normal tissues. Transgelin-2 was observed only in the SCC tissues, and also those in the early stage. CONCLUSIONS AND CLINICAL RELEVANCE: The present study successfully identified three upregulated proteins in the uterine cervical SCC by proteomic analyses, and suggested that these proteins could be the candidates for new biomarkers for early diagnosis of SCC and molecular target therapies.

Evidence of post-translational modification of the tumor suppressor maspin under oxidative stress.

Maspin, identified as a 42 kDa unique tumor suppressive serine protease inhibitor (serpin), has multifaceted biological functions by interacting with various target molecules under physiological and pathological conditions including oxidative stress. However, the type of post-translational modification that confers the specific binding affinity of maspin to target molecules, such as glutathione S-transferase (GST), has not been determined. The aim of this study, therefore, is to analyze the molecular heterogeneity of maspin and to identify its modifications in the normal mammary epithelial cell line, MCF-10A, which is known to express the maspin protein abundantly, using electrophoretic analysis. Conventional SDS-PAGE analysis of MCF-10A cell extracts showed that endogenous maspin is composed of both an intact form observed as a 42 kDa band and a smaller form observed as a 36 kDa band. Interestingly, a brief exposure of MCF-10A cells to 10 mM hydrogen peroxide (H2O2) led to the appearance of a novel endogenous maspin form, as demonstrated by non-denaturing PAGE and non-reducing SDS-PAGE. Two-dimensional sequential non-reducing/reducing SDS-PAGE supported that this novel form was generated by intramolecular disulfide-bonded linkage under oxidative stress, and this oxidized maspin form also existed under physiological conditions. Furthermore, a glutathione (GSH) bead pull-down assay revealed that the intramolecular disulfide-bonded maspin lost its binding activity to endogenous GST, indicating that intramolecular disulfide-bonded maspin might have some distinct properties under oxidative stress, although the precise biological significance of this modification remains elusive. In conclusion, we have shown that maspin undertakes different modifications under oxidative stress.

Tumor-related protein, the squamous cell carcinoma antigen binds to the intracellular protein carbonyl reductase.

Squamous cell carcinoma antigen (SCCA) is a useful tumor marker for diagnosis and management of squamous cell carcinoma. Recent reports have shown that SCCA can influence the invasion or metastasis of cancer cells. However, it remained unclear how SCCA acts to mediate these biological functions. To solve this question, at first, SCCA1- and SCCA2-glutathione S-transferase fusion protein were used to purify a protein which binds to SCCA1 or SCCA2, and the combined protein was identified by proteomic analysis. Secondly, immunocytochemical and immunohistochemical analyses were performed to investigate the localization of this protein. Third, Western blotting was performed to analyze the expression levels of this protein in keratinocytes and six kinds of uterine squamous cell carcinoma cell lines. Both SCCA1 and SCCA2 molecules bind to the cytoplasmic protein, which was identified to be carbonyl reductase (CR). The immunostaining analyses revealed that CR is located in the cytoplasm of keratinocytes and the normal squamous epithelial cells of the uterine cervix as well as SCCA1 and SCCA2. The CR expression levels in six kinds of squamous cell carcinoma cell lines were lower compared to those in keratinocytes. In conclusion, CR binds to SCCA1 and SCCA2 and they are co-located in the same layer of the squamous epithelium, suggesting that CR may collaborate with SCCA1 and SCCA2 to mediate cancer behavior such as invasion or metastasis.

Relationship between decreased expression of squamous cell carcinoma antigen 2 and E-cadherin in primary cervical cancer lesions and lymph node metastasis.

Squamous cell carcinoma antigen (SCCA) has been used for the management of squamous cell carcinoma, especially in order to evaluate therapeutic effects and monitor recurrence. Recent studies have shown that SCCA performs several biological functions and can influence the behavior of cancer cells. It is well known that altered expression of E-cadherin is involved in the process of cancer invasion and metastasis. The present study was therefore undertaken to investigate the relationship between the expression of SCCA, E-cadherin and lymph node metastasis in advanced cervical squamous cell carcinoma patients. We studied 70 patients who had undergone radical hysterectomy and pelvic lymphadenectomy for stage IB, IIA and IIB of the disease, without pretreatments. Immunohistochemistry, using monoclonal antibodies against SCCA2 and E-cadherin, was performed to examine the relationship between SCCA2 and E-cadherin expression patterns in primary cancer lesions and lymph node metastasis. There was a significant positive relationship between the two expression patterns in primary cancer lesions (p<0.01). Both exhibited a heterogeneous expression pattern in the primary tumor which indicated a significant relationship with lymph node metastasis (p<0.01). Our data clearly show that SCCA2 expression is significantly related to E-cadherin expression and that the heterogeneous pattern of SCCA and E-cadherin in primary lesions is strongly associated with the high incidence of lymph node metastasis in cervical squamous cell carcinoma. These findings suggest that SCCA2 may be involved in cancer behavior such as metastasis, and as such can be a useful marker in predicting lymph node metastasis.

E-cadherin increases squamous cell carcinoma antigen expression through phosphatidylinositol-3 kinase-Akt pathway in squamous cell carcinoma cell lines.

Squamous cell carcinoma antigen (SCCA) has been used for the management of squamous cell carcinoma, especially for evaluating therapeutic effects and monitoring recurrence. It has been reported that SCCA has several biological activities and influences behavior of cancer cells. E-cadherin is a cell adhesion molecule and plays important roles in the process of cancer invasion and metastasis. Our previous studies have shown that blockage of E-cadherin action by anti-E-cadherin antibody treatment suppresses SCCA production in squamous cell carcinoma cells. This finding strongly suggests that E-cadherin regulates SCCA expression. The present study was, therefore, undertaken to investigate the correlation between E-cadherin and SCCA2. For this purpose, E-cadherin cDNA was transfected into squamous cell carcinoma cell lines, SiHa and SKG IIIa. Overexpression of E-cadherin increased SCCA2 expression together with cell aggregation. We also examined the involvement of phosphatidylinositol 3-kinase (PI3K)-Akt pathway, which is one of major signaling pathways from E-cadherin. E-cadherin transfection increased phosphorylated Akt expression concomitantly with the increase in SCCA2 expression, and the increased SCCA2 expression was inhibited by a PI3K inhibitor. In conclusion, SCCA2 is up-regulated by E-cadherin through PI3K-Akt pathway, suggesting that SCCA2, as well as E-cadherin, may be involved in the regulation of cancer behavior.

Suppression of SCC antigen promotes cancer cell invasion and migration through the decrease in E-cadherin expression.

Squamous cell carcinoma antigen (SCCA) is a useful tumor marker for diagnosis and management of squamous cell carcinoma. Recent studies have shown that SCCA can influence the behavior of cancer cells. It is well known that cell-cell adhesion is an important factor for the progression of cancer. The present study, therefore, was undertaken to investigate the effect of SCCA2 on the cell adhesion related molecule, E-cadherin, and cancer cell behavior. For this purpose, antisense SCCA2 cDNA was transfected into human uterine cancer cell lines, SKG IIIa and SiHa, which express SCCA2. Suppression of SCCA2 expression by antisense SCCA2 cDNA transfection decreased E-cadherin expression and promoted cell migration and invasion as well as the blockage of E-cadherin function by anti-E-cadherin antibody administration. In conclusion, SCCA2 regulates cell migration and invasion via E-cadherin expression, suggesting that SCCA2 may be involved in cancer behavior such as invasion or metastasis.

Different expression patterns of intact forms of squamous cell carcinoma antigens between normal and malignant cervical squamous epithelial tissues: nondenaturing polyacrylamide gel electrophoretic analysis.

Squamous cell carcinoma antigen (SCCA), a 45-kDa tumor-associated serpin, mainly consists of two highly homologous molecules, SCCA1 and SCCA2, which possess unique proteinase inhibitory properties. Importantly, our previous study demonstrated that an intact structure of SCCAs, and not a cleaved form yielded by interacting with target proteinase, is essential for their function as a serpin. The aim of this study is therefore, to develop a simple method of analyzing expression patterns of intact forms of SCCAs (functional SCCAs) in cervical squamous epithelial tissues and to investigate whether there are any differences in the expression of intact forms of SCCAs between normal and malignant cervical squamous epithelial tissues. We used nondenaturing polyacrylamide gel electrophoresis (PAGE) with immunoblotting. The newly generated antibody, Pab Y2, recognizes only intact form of SCCAs, while the conventional antibody, Mab 27, reacts with the cleaved form of SCCA1 as well as intact forms of SCCAs. Nondenaturing PAGE using Pab Y2 showed that an intact form of SCCAs in the heat-treated tissue extract at 60 degrees C for 2 h was separated into at least five bands, termed as bands A-E from cathode to anode. By comparison with two-dimensional electrophoresis patterns of SCCAs, it was found that the first three bands, i.e. bands A-C, are derived from the intact form of SCCA1, while the other two bands, i.e. band D and E are from the intact form of SCCA2. Specifically, band E, but not band D, of SCCA2 is apparently increased in squamous cell carcinomas compared with normal squamous epithelium. In conclusion, this novel analytical approach will be useful for investigating the different expression patterns of functional SCCAs between normal and malignant cervical squamous epithelial tissues.

Tumor-associated serpin, squamous cell carcinoma antigen stimulates matrix metalloproteinase-9 production in cervical squamous cell carcinoma cell lines.

Squamous cell carcinoma antigen (SCCA) is clinically used as a tumor marker for patients with squamous cell carcinoma of various organs. SCCA1 and its highly homologous molecule, SCCA2, belong to the serine proteinase inhibitors (serpins) family, suggesting that these proteins may be involved in the malignant behavior of squamous cell carcinoma cells. The aim of this study is to functionally characterize these tumor-associated serpins regarding the potential to influence the production of matrix metalloproteinases (MMPs), which play a key role in tumor cell invasion and metastasis. Cervical squamous cell carcinoma cell lines, CaSki cells and SKG-IIIa cells were incubated with SCCA1 or SCCA2 and MMP production was analyzed by gelatin zymography. Both SCCA1 and SCCA2 significantly increased production of proMMP-9, but not proMMP-2. These stimulatory effects were still observed when cells were treated with SCCA mutants lacking the proteinase inhibitory activity of serpins. Furthermore, treatments with various forms of SCCAs, which are generated by interacting with their target proteinases, diminished the stimulatory effect of SCCAs, implying the importance of the conformational structure of SCCAs in the stimulatory effects of SCCAs on proMMP-9 production. In addition, in vitro invasion assay showed that SCCA1 and SCCA2 significantly promoted the activity of cell invasion. It is concluded that SCCAs can alter the invasive phenotype of cervical squamous cell carcinoma cells, probably by stimulating proMMP-9 production, and that intact conformational structure of SCCAs, but not proteinase inhibitory activity of serpins, is required for its stimulatory activity on proMMP-9 production.

Promoter analyses of SCC antigen genes.

SCC antigen (SCCA) has been used as a tumor marker for squamous cell carcinoma. Analyses of the SCCA1 and SCCA2 genes, which are almost identical, and their promoters have been reported. Recently it was found that both SCCAs were stimulated by interleukin (IL)-4 and IL-13. Here we analyzed the promoter activity of both SCCAs in the 5'-flanking region, exon 1, and intron 1 to evaluate a putative STAT6 binding site. The addition of intron 1 to the luciferase assay constructs including the 5'-flanking region significantly augmented the promoter activity of both SCCA1 and SCCA2. Furthermore, deletion analyses of intron 1 revealed that a 50-bp fragment of intron 1 that includes putative STAT6 binding site was responsible for the increased promoter activity. Although the sequences of SCCA1 and SCCA2 are very similar in the 5'-flanking region, the analysis of the -337 single nucleotide polymorphism of SCCA2 indicated that this polymorphism may underlie the difference in promoter activity between SCCA1 and SCCA2.

Regulation of squamous cell carcinoma antigen production by E-cadherin mediated cell-cell adhesion in squamous cell carcinoma cell line.

Squamous cell carcinoma antigen (SCCA) is a useful tumor marker for diagnosis and management of squamous cell carcinoma. It is well known that cell-cell adhesion is important for progression of cancer. However, it is not clarified whether cell-cell adhesion affects SCCA production in squamous cell carcinoma. The present study was, therefore, undertaken to investigate whether E-cadherin-mediated cell-cell adhesion affects SCCA production in squamous cell carcinoma of the uterine cervix. SKG-IIIa cells or CaSki cells, cervical squamous cell carcinoma cell lines, were treated with anti-E-cadherin antibodies (1 microg/ml) up to 72 h. The cells were dissociated, and SCCA content in the cytosol and SCCA mRNA levels were significantly decreased compared to the control group treated with mouse IgG. Secondly, the signaling pathway for SCCA production mediated by E-cadherin was examined. Phosphatidylinositol (PI) 3-kinase is a well-known mediator of E-cadherin-mediated biological events. The treatment with a PI 3-kinase inhibitor suppressed SCCA production in SKG-IIIa cells. It is concluded that E-cadherin mediated cell-cell adhesion maintains SCCA production through PI 3-kinase in squamous cell carcinoma.

Electrophoretic analysis of the cleaved form of serpin, squamous cell carcinoma antigen-1 in normal and malignant squamous epithelial tissues.

The aim of this study was to detect the cleaved form of serine proteinase inhibitor (serpin), squamous cell carcinoma (SCC) antigen-1 in normal and malignant squamous epithelial tissues, which implies the presence of its target proteinase. The cleaved SCC antigen-1 in normal squamous epithelium was identified as a single spot with pI 6.35 and M(r) 40,000 by two-dimensional electrophoresis (2-DE) combined with immunoblotting. Interestingly, the cleaved form showed different biochemical properties in heat stability or immunoreactivity with a monoclonal antibody for SCC antigen (Mab 426) compared to intact SCC antigen-1. Furthermore, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of tissue extracts showed an abundant 40 kDa band of cleaved SCC antigen-1 in tumor tissue compared to normal tissue. Among the potential target proteinase of SCC antigen-1, immunoblotting analyses revealed that cathepsin L2 was remarkably overexpressed in tumor tissue, while cathepsin L was expressed in both normal and tumor tissues. These findings indicate that SCC antigen-1 interacts with specific endogenous proteinases such as cathepsins L and L2 in physiological and pathological states of squamous epithelium.

Genetic alterations related to lymph node metastasis and peritoneal dissemination in epithelial ovarian cancers.

Genetic alterations are assumed to be necessary for the development and progression of ovarian cancer. However, the genetic alterations that occur during lymph node metastasis and peritoneal dissemination are poorly understood. In the present study, we used comparative genomic hybridization to detect genetic alterations in 30 tumors from patients with primary ovarian cancers and analyzed the associations of these genetic alterations with clinical stage and surgical pathological factors, such as histological grade, lymph node metastasis, and peritoneal dissemination. The total number of genetic alterations per tumor ranged from 0 to 39, with an average of 17.7 alterations per tumor. Among the genetic alterations in ovarian cancers, gains on chromosomes 8q and 3q and losses on chromosomes 17p, 18q, and 4q were observed frequently. Although the difference in total numbers of genetic alterations between early-stage tumors and advanced-stage tumors was not significant, the difference was significant when high-grade cancers were compared with low-grade cancers. Eight regions on seven chromosomes showed genetic alterations related to lymph node metastasis or peritoneal dissemination. Gain at 11q13-q14 and loss at 17q11.2-q21 were related not only to lymph node metastasis and peritoneal dissemination but also to clinical stage and histological grade.

Comparative genomic hybridization detects genetic alterations during early stages of cervical cancer progression.

Invasive cervical carcinoma is thought to arise from cervical intraepithelial neoplasm (CIN). Genetic changes that occur during progression of CIN to cervical carcinoma are poorly understood, although they appear to be directly involved in this process. We used comparative genomic hybridization (CGH) with precise microdissection and degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR) to detect genetic alterations in normal epithelial, CIN, and invasive carcinoma tissues colocalized in tumors from 18 patients with squamous cell carcinoma of the uterine cervix. Gains on chromosome 1 and on 3q and losses on 2q, 3p, 4, 6p, 11q, and 17p were frequent alterations found in CIN and invasive carcinoma lesions. Interestingly, several of these genetic changes were observed in preinvasive carcinoma lesions. The frequency and average number of genetic alterations corresponded directly to the extent to which the cervical carcinoma had progressed. Frequent alterations were found in more than 90% of CIN III lesions. Gains on 3q and losses on 11q were the most prevalent genetic alterations found in association with uterine cervix carcinogenesis. The common regions of alteration were 3q26.1-q28 and 11q23-qter. The majority of tumor samples showed variability in genetic alterations across lesion types within a single specimen.