Increased expression of p34cdc2 and its kinase activity in human gastric and colonic carcinomas

Overexpression of aldolase, fructose-bisphosphate C and its association with spheroid formation in colorectal cancer

Colorectal cancer (CRC) is a leading cause of cancer-related death worldwide. The spheroid colony formation assay is a useful method to identify cancer stem cells (CSCs). Using the DLD-1 and WiDr CRC cell lines, we performed microarray analyses of spheroid body-forming and parental cells and demonstrated that aldolase, fructose-bisphosphate C (ALDOC) was overexpressed in the spheroid body-forming cells of both lines. Cells transfected with small interfering RNA against ALDOC demonstrated lower proliferation, migration, and invasion compared with negative control cells. Both the number and size of spheres produced by the CRC cells were significantly reduced by ALDOC knockdown. Additionally, inhibition of ALDOC reduced lactate production. Immunohistochemistry was used to analyze ALDOC protein expression in tissues from 135 CRC patients and revealed that 66 (49%) cases were positive for ALDOC. The ALDOC-positive cases were associated with higher T and M grades and, as determined by Kaplan-Meier analysis, a poorer prognosis. Univariate and multivariate analyses indicated that ALDOC expression was an independent prognostic factor for CRC patients. Furthermore, ALDOC expression was associated with CD44 expression. These results suggest that ALDOC contributes to CRC progression and plays an important role in CSCs derived from CRC.

Overexpression of claspin promotes docetaxel resistance and is associated with prostate-specific antigen recurrence in prostate cancer

Although docetaxel (DTX) confers significant survival benefits in patients with castration‐resistant prostate cancer (CRPC), resistance to DTX inevitably occurs. Therefore, clarifying the mechanisms of DTX resistance may improve survival in patients with CRPC. Claspin plays a pivotal role in DNA replication stress and damage responses and is an essential regulator for the S‐phase checkpoint. CLSPN is an oncogenic gene that contributes to tumor proliferation in several human solid tumors. However, the clinical significance of claspin in prostate cancer (PCa) has not been examined. The present study aimed to elucidate the role of claspin and its relationship with DTX resistance in PCa. We immunohistochemically analyzed the expression of claspin in 89 PCa cases, of which 31 (35%) were positive for claspin. Claspin‐positive cases were associated with higher Gleason score, venous invasion, and perineural invasion. Kaplan–Meier analysis showed that high claspin expression was related to poor prostate‐specific antigen (PSA) relapse‐free prognosis. In a public database, high CLSPN expression was associated with poor PSA relapse‐free prognosis, Gleason score, T stage, lymph node metastasis, CRPC, and metastatic PCa. Claspin knockdown by siRNA decreased cell proliferation, upregulated DTX sensitivity, and suppressed the expression of Akt, Erk1/2, and CHK1 phosphorylation in DU145 and PC3 cell lines. Furthermore, claspin expression was much more upregulated in DTX‐resistant DU145 (DU145‐DR) than in parental DU145 cells. Claspin knockdown significantly upregulated the sensitivity to DTX in DU145‐DR cells. These results suggest that claspin plays an important role in PCa tumor progression and DTX resistance.

Clinicopathologic features of TDO2 overexpression in renal cell carcinoma

BACKGROUND

Tryptophan 2,3-dioxygenase (TDO2) is the primary enzyme catabolizing tryptophan. Several lines of evidence revealed that overexpression of TDO2 is involved in anoikis resistance, spheroid formation, proliferation, and invasion and correlates with poor prognosis in some cancers. The aim of this research was to uncover the expression and biofunction of TDO2 in renal cell carcinoma (RCC).

METHODS

To show the expression of TDO2 in RCC, we performed qRT-PCR and immunohistochemistry in integration with TCGA data analysis. The interaction of TDO2 with PD-L1, CD44, PTEN, and TDO2 expression was evaluated. We explored proliferation, colony formation, and invasion in RCC cells line affected by knockdown of TDO2.

RESULTS

RNA-Seq and immunohistochemical analysis showed that TDO2 expression was upregulated in RCC tissues and was associated with advanced disease and poor survival of RCC patients. Furthermore, TDO2 was co-expressed with PD-L1 and CD44. In silico analysis and in vitro knockout of PTEN in RCC cell lines revealed the ability of PTEN to regulate the expression of TDO2. Knockdown of TDO2 suppressed the proliferation and invasion of RCC cells.

CONCLUSION

Our results suggest that TDO2 might have an important role in disease progression and could be a promising marker for targeted therapy in RCC. (199 words).

TDO2 overexpression correlates with poor prognosis, cancer stemness, and resistance to cetuximab in bladder cancer

Background

Bladder cancer (BC) is the 10th most common cancer in the world. BC with muscle invasion results in a poor prognosis and is usually fatal. Cancer cell metabolism has an essential role in the development and progression of tumors. Expression of tryptophan 2,3‐dioxygenase (TDO2) is associated with tumor progression and worse survival in some other cancers. However, no studies have been performed to uncover the biofunctional roles of TDO2 in BC.

Aim

This study aim to investigate the clinicopathologic significance of TDO2 in BC.

Methods and results

TDO2 expression was evaluated by qRT‐PCR and immunohistochemistry in an integrated analysis with the Cancer Genome Atlas (TCGA) and other published datasets. TDO2 overexpression was significantly associated with T classification, N classification, and M classification, tumor stage, recurrence, and basal type, and with the expression of CD44 and aldehyde dehydrogenase 1 (ALDH1) in BC. High TDO2 expression correlated with poor outcome of BC patients. Using BC cell lines with knockdown and forced expression of TDO2, we found that TDO2 was involved in the growth, migration, and invasiveness of BC cells. Moreover, TDO2 was found to be crucial for spheroid formation in BC cells. Importantly, TDO2 promoted BC cells resistance to cetuximab through integration of the EGFR pathway.

Conclusion

Our results indicate that TDO2 might take an essential part in BC progression and could be a potential marker for targeted therapy in BC.

SPC18 Expression Is an Independent Prognostic Indicator of Patients with Esophageal Squamous Cell Carcinoma

OBJECTIVES

Esophageal cancer is the sixth most common malignancy worldwide. Signal peptidase complex 18 (SPC18) protein, which is encoded by the SEC11A gene, is one of the subunits of the signal peptidase complex and plays an important role in the secretion of proteins including transforming growth factor α (TGF-α). In this study, we investigated the significance of SPC18 expression in human esophageal squamous cell carcinoma (ESCC).

METHODS

SPC18 expression was examined by immunohistochemistry. RNA interference was used to inhibit SPC18 expression in ESCC cell lines. To examine cell viability, we performed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. The effects of SPC18 inhibition on epidermal growth factor receptor (EGFR) signaling were analyzed by Western blot.

RESULTS

In total, 46 (50%) of 92 ESCC cases were positive for SPC18. SPC18 staining was observed more frequently in stage II/III/IV cases than in stage I cases (p = 0.028). We found that SPC18 expression was significantly associated with increased cancer-specific mortality (p = 0.006, log-rank test). SPC18 expression was frequently found in EGFR-positive cases compared with EGFR-negative cases. Cell proliferation and EGFR signaling were inhibited by SPC18 knockdown.

CONCLUSION

Specific inhibitors of SPC18 may be promising anticancer drugs for patients with ESCC.

Claspin overexpression is associated with high-grade histology and poor prognosis in renal cell carcinoma

Renal cell carcinoma (RCC) is one of the most common human cancers. We previously reported that claspin is a key regulator in the progression of gastric cancer, and it likely plays an important role in cancer stem cells of gastric cancer. However, the significance of claspin in RCC has not been examined. First, we analyzed the expression and distribution of claspin in 95 RCC cases by immunohistochemistry. In the nonneoplastic kidney, the staining of claspin was either weak or absent, whereas RCC tissue showed nuclear staining. In total, claspin expression was detected in 45 (47%) of 95 RCC cases. The claspin staining appeared relatively stronger in high nuclear grade RCC than in low nuclear grade RCC. Claspin-positive RCC cases were associated with higher T grade, tumor stage, nuclear grade, vein invasion, and poorer prognosis. CLSPN siRNA treatment decreased RCC cell proliferation. The levels of phosphorylated Erk and Akt were lower in CLSPN siRNA-transfected RCC cells than in control cells. In addition, claspin was coexpressed with CD44, epidermal growth factor receptor, p53, and programmed death ligand-1. These results suggest that claspin plays an important role in tumor progression in RCC and might be a prognostic marker and novel therapeutic target molecule.

SEC11A Expression Is Associated with Basal-Like Bladder Cancer and Predicts Patient Survival

OBJECTIVES

Bladder cancer (BC) is a common malignancy worldwide. Signal peptidase complex 18 (SPC18) protein, which is encoded by the SEC11A gene, is one of the subunits of the signal peptidase complex and induces transforming growth factor-α secretion. In the present study, we analyzed the expression and function of SPC18 protein in human BC.

METHODS

Expression of SPC18 was analyzed by immunohistochemistry. RNA interference was used to inhibit SEC11A expression in BC cell lines. For constitutive expression of the SEC11A gene, a SEC11A expression vector was transfected into BC cell lines. To examine cell viability, we performed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Modified Boyden chamber assays were used to examine cell invasiveness.

RESULTS

SPC18 was upregulated in 54% of 81 BC cases. SPC18 expression served as an independent prognostic classifier of patients with BC. SPC18-positive BC cases frequently expressed cytokeratin 5/6, a marker of basal-like BC. Cell growth and invasiveness were inhibited by SEC11A knockdown and enhanced by forced expression of SEC11A.

CONCLUSION

These results indicate that SPC18 plays an important role in the progression of BC. Specific inhibitors of SPC18 may be promising anticancer drugs for patients with basal-like BC.

Clinicopathological significance of claspin overexpression and its association with spheroid formation in gastric cancer

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. Spheroid colony formation is a useful method to identify cancer stem cells (CSCs). The aim of this study was to identify a novel prognostic marker or therapeutic target for GC using a method to identify CSCs. We analyzed the microarray data in spheroid body-forming and parental cells and focused on the CLSPN gene because it is overexpressed in the spheroid body-forming cells in both the GC cell lines MKN-45 and MKN-74. Quantitative reverse-transcription polymerase chain reaction analysis revealed that CLSPN messenger RNA expression was up-regulated in GC cell lines MKN-45, MKN-74, and TMK-1. Immunohistochemistry of claspin showed that 94 (47%) of 203 GC cases were positive. Claspin-positive GC cases were associated with higher T and N grades, tumor stage, lymphatic invasion, and poor prognosis. In addition, claspin expression was coexpressed with CD44, human epidermal growth factor receptor type 2, and p53. CLSPN small interfering RNA treatment decreased GC cell proliferation and invasion. These results indicate that the expression of claspin might be a key regulator in the progression of GC and might play an important role in CSCs of GC.

The significance of scirrhous gastric cancer cell lines: the molecular characterization using cell lines and mouse models

Scirrhous gastric cancer (SGC) exhibits aggressiveness of the rapid infiltrating tumor cells with abundant fibroblasts. Experimental studies using SGC cell lines have obtained useful information about this cancer. Our literature search divulged a total of 18 SGC cell lines; two cell lines were established from primary SGC and the other lines were established from a metastatic lesion of SGC. Fibroblast growth factor receptor 2 (FGFR2) and transforming growth factor-beta receptor (TβR) are linked to the rapid development of SGC. Cross-talk between the cancer cells and cancer-associated fibroblasts (CAFs) has been shown to contribute to the progression of SGC. Chemokine (C-X-C motif) receptor 1 (CXCR1) from SGC cells might be associated with the abundant CAFs in cancer microenvironments. The in vivo models established using SGC cell lines are expected to serve as a useful tool for the development of drugs such as FGFR2 inhibitors, TβR inhibitors, and CXCR1 inhibitors, which might be promising as SGC treatments. However, the number of available SGC cell lines is insufficient for the clarification of the entire biologic behavior of SGC. Since the mechanisms responsible for the characteristic aggressiveness of SGC are not fully elucidated, the establishment of new SGC cell lines could help clarify the biological behavior of SGC and contribute to its treatment.

Abnormalities in Cell Cycle Control in Cancer and Their Clinical Implications

Recent studies indicate that the functions of several genes that control the cell cycle are altered during the carcinogenic process and that these changes perturb both cell proliferation and genomic stability, thus promoting cell transformation and enhancing the process of tumor progression. The purpose of this paper is to review current information on the role of cyclins and related genes in the control of the mammalian cell cycle, the types of abnormalities in these genes found in human tumors and the possible clinical implications of these findings.

Expression and functional regulation of stemness gene Lgr5 in esophageal squamous cell carcinoma

Cancer stem cells (CSCs) are defined as a rare subpopulation of undifferentiated cells with biological characteristics that include the capacity for self-renewal, differentiation into various lineages, and tumor initiation. To explore the mechanism of CSCs in esophageal squamous cell carcinoma (ESCC), we focused on Leucine-rich repeat containing G protein-coupled receptor 5 (Lgr5), a target gene of the Wnt signaling pathway, which has been identified as a marker of intestinal stem cells and shown to be overexpressed in several human malignancies. Lgr5 expression was significantly correlated with lymph node metastasis, increased depth of invasion, increased tumor size, advanced differentiation, higher AJCC stage and poorer survival. Silencing of Lgr5 expression in the ESCC cell line KYSE450 by small interfering RNA (siRNA) strongly inhibited cell proliferation, migration and invasion ability, the expression of CSCs-related genes and Wnt/β-catenin signaling. In addition, Lgr5 was highly expressed in ESCC spheroid body cells, which were identified by high expression of CSCs-related genes, and high tumorigenicity in vivo. Taken together, these results demonstrate that Lgr5 activation of Wnt/β-catenin signaling is a potential mechanism to promote the progression of ESCC and ESCC stem cell renewal, and Lgr5 may be used as a molecular target for the development of treatments for ESCC.

Expression and function of Uc.160+, a transcribed ultraconserved region, in gastric cancer

BACKGROUND

Transcribed ultraconserved regions (T-UCRs) are a novel class of noncoding RNAs that are highly conserved among the orthologous regions in most vertebrates. It has been reported that T-UCRs have distinct signatures in human cancers. We previously discovered the downregulation of T-UCR expression in gastric cancer (GC), indicating that T-UCRs could play an important role in GC biology. Uc.160+, a T-UCR reported to be downregulated in human cancer, has not been examined in GC.

METHODS

We analyzed the expression pattern of Uc.160+ in nonneoplastic and tumor tissues of the stomach by using uantitative reverse transcription polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH), specifically focusing on the mechanism of transcriptional regulation and target genes that are regulated by T-UCRs. We also attempted to determine the effect of Uc.160+ expression on biological features of GC cell lines by Western blotting.

RESULTS

On the basis of the qRT-PCR and ISH results, Uc.160+ expression in adenoma and GC tissues was clearly downregulated compared with that in nonneoplastic mucosa tissues of the stomach. Cancer-specific DNA methylation in the promoter region of Uc.160 was observed by bisulfite genomic DNA sequencing analysis. The effect of DNA methylation on Uc.160+ expression was further confirmed by reporter gene assay. We also revealed that Uc.160+ inhibited the phosphorylation of Akt by regulating phosphatase and tensin homolog (PTEN) expression.

CONCLUSIONS

These results indicate that Uc.160+ could possibly have a tumor suppressive role in GC.

Overexpression of KIFC1 and its association with spheroid formation in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common human cancers. We previously reported that KIFC1 is involved in gastric cancer pathogenesis and that KIFC1 plays an important role in gastric cancer spheroid colony formation. However, the significance of KIFC1 in ESCC has not been examined. In the present study, we analyzed the expression and distribution of KIFC1 in 132 ESCC cases by immunohistochemistry. In contrast to weak or no staining of KIFC1 in non-neoplastic mucosa, ESCC tissue showed stronger, more extensive KIFC1 staining. In total, 95 (72%) of 132 ESCC cases were positive for KIFC1. Immunostaining of ALDH1 was also performed, and KIFC1-positive ESCC cases were significantly frequently found in ALDH1-positive ESCC cases compared with ALDH1-negative ESCC cases. Spheroid colony formation is an effective method to characterize CSCs, thus we analyzed sphere number and size at 15days in ESCC cells downregulated for KIFC1 by siRNA transfection. Both the number and size of sphere from TE-1 cells were significantly reduced in KIFC1 siRNA-transfected TE-1 cells than in negative control siRNA-transfected cells. These results suggest that KIFC1 plays an important role in ESCC pathogenesis.

Overexpression of the transmembrane protein BST-2 induces Akt and Erk phosphorylation in bladder cancer

Bladder cancer, the majority of which is urothelial carcinoma (UC), is a common malignancy worldwide. Genes encoding transmembrane/secretory proteins expressed specifically in certain cancers may be ideal biomarkers for cancer diagnosis and may represent therapeutic targets. In the present study, the expression and function of the bone marrow stromal cell antigen 2 (BST2) gene was analyzed in UC. Reverse transcription-quantitative polymerase chain reaction demonstrated that expression of BST2 in normal tissue samples was the highest in liver tissue. However, expression of BST2 in UC tissue samples was higher than in normal liver. Immunohistochemical analysis revealed weak or no staining of BST-2 in non-neoplastic mucosa, whereas UC tissue exhibited stronger and more extensive staining compared with non-neoplastic mucosa. BST-2 staining was observed mainly on UC cell membranes. In total, 28 (41%) of 69 UC cases were positive for BST-2. UC cases positive for BST-2 were more frequently T2/3/4 cases [so-called muscle-invasive bladder cancer (MIBC)] than Ta/is/1 cases (P=0.0001). However, Kaplan-Meier analysis demonstrated no association between BST-2 expression and survival. BST2 small interfering RNA (siRNA)-transfected T24 cells exhibited significantly reduced cell growth relative to negative control siRNA-transfected T24 cells. The levels of phosphorylated Akt and extracellular signal-regulated kinase were lower in BST2 siRNA-transfected T24 cells than in control cells. These results suggest the involvement of BST-2 in the pathogenesis of UC. Since BST-2 is expressed on the cell membrane, BST-2 may be a good therapeutic target for MIBC.

Overexpression of KIF11 in Gastric Cancer with Intestinal Mucin Phenotype

OBJECTIVE

Gastric cancer (GC) is one of the most common human cancers. A useful method of gastric cancer stem cell (CSC) characterization is spheroid colony formation. Previously, we reported that KIF11 expression is >2-fold in spheroid-body-forming GC cells compared with parental cells. Here, we analyzed the expression and distribution of KIF11 in human GC by immunohistochemistry.

METHODS

Expression of KIF11 in 165 GC cases was determined using immunohistochemistry. For mucin phenotypic expression analysis of GC, immunostaining of MUC5AC, MUC6, MUC2 and CD10 was evaluated. RNA interference was used to inhibit KIF11 expression in GC cell lines.

RESULTS

In total, 119 of 165 GC cases (72%) were positive for KIF11. Expression of KIF11 was not associated with any clinicopathologic characteristics; however, it was observed frequently in GC exhibiting an intestinal phenotype. Both the number and size of spheres formed by MKN-74 cells were significantly reduced following transfection of KIF11-targeting siRNA compared with negative-control siRNA. Furthermore, levels of phosphorylated Erk1/2 were lower in KIF11 siRNA-transfected cells than with negative-control siRNA-transfected cells.

CONCLUSION

These results indicate that KIF11 is involved in intestinal mucin phenotype GC.

Induction of KIFC1 expression in gastric cancer spheroids

Gastric cancer (GC) is one of the most common human cancers. Spheroid colony formation is an effective model for characterization of cancer stem cells. However, gene expression profiles of spheroid colonies obtained from GC cells have not been examined. We performed microarray analyses by Human Genome U133 Plus 2.0 Array in spheroid body-forming and parental cells from MKN-45 and MKN-74 GC cell lines. Kinesin family member C1 (KIFC1) was expressed >2-fold higher in spheroid body-forming cells than in parental cells in both GC lines. Both the number and size of spheres from MKN-45 cells were significantly reduced upon KIFC1 siRNA-transfection compared with negative control siRNA-transfection. Immunohistochemical analysis of 114 GC tissue samples revealed that 42 (37%) of GC cases were positive for KIFC1 expression. GC cases positive for KIFC1 were found more frequently in stage III/IV cases than in stage I/II cases. GC cases positive for KIFC1 were found more frequently in intestinal type GC cases than in diffuse type GC cases. Furthermore, KIFC1-positive GC cases showed high Ki-67 labeling index. Kaplan-Meier analysis demonstrated that KIFC1 expression was not associated with survival. We found positive expression of KIFC1 in CD44‑positive GC and aldehyde dehydrogenase 1 (ALDH1)-positive GC cells. Our results showed that KIFC1 is overexpressed in GC. Since knockdown of KIFC1 inhibited sphere formation, KIFC1 likely plays an important role in cancer stem cells.

Fukutin, identified by the Escherichia coli ampicillin secretion trap (CAST) method, participates in tumor progression in gastric cancer

BACKGROUND

Gastric cancer (GC) is the fifth commonest malignancy worldwide and still one of the leading causes of cancer-related death. The aim of this study was to identify a novel prognostic marker or therapeutic target for GC.

METHODS

We analyzed candidate genes from our previous Escherichia coli ampicillin secretion trap (CAST) libraries in detail, and focused on the FKTN gene because it was overexpressed in both GC cell line CAST libraries, MKN-1 and MKN-45.

RESULTS

Quantitative reverse transcriptase PCR analysis of FKTN revealed that FKTN messenger RNA was overexpressed in nine of 28 (32.1 %) GC tissue samples compared with nonneoplastic gastric mucosa. Immunostaining of fukutin showed that 297 of 695 cases (42.7 %) were positive for fukutin. Fukutin-positive GC cases were significantly associated with differentiated histological features, and advanced T grade and N grade. In addition, fukutin expression was observed more frequently in the intestinal phenotype (51 %) of GC than in other phenotypes (37 %) when defined by the expression patterns of mucin 5AC, mucin 6, mucin 2, and CD10. FKTN small interfering RNA treatment decreased GC cell proliferation.

CONCLUSIONS

These results indicate that the expression of fukutin may be a key regulator for progression of GC with the intestinal mucin phenotype.

TSPAN8, identified by Escherichia coli ampicillin secretion trap, is associated with cell growth and invasion in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common human cancers. Genes expressed only in cancer tissue, especially on the cell membrane, will be useful biomarkers for cancer diagnosis and therapeutics.

METHODS

To identify novel genes encoding transmembrane protein specifically expressed in GC, we generated an Escherichia coli ampicillin secretion trap (CAST) library from diffuse-type GC cell line MKN-45. CAST is a survival-based signal sequence trap method that exploits the ability of mammalian signal sequences to confer ampicillin resistance to a mutant β-lactamase lacking the endogenous signal sequence.

RESULTS

By sequencing 1,536 colonies, we identified 23 genes encoding the transmembrane protein present in GC. Among these genes, TSPAN8 (also known as CO-029 and TM4SF3) gene, which encodes transmembrane protein tetraspanin 8, was emphasized as a candidate. Immunohistochemical analysis of tetraspanin 8 in human GC tissues revealed that 72 (34 %) of 210 GC cases were positive for tetraspanin 8, and microvessel density was significantly higher in tetraspanin 8-positive GC than in tetraspanin 8-negative GC. Furthermore, univariate and multivariate analyses revealed that tetraspanin 8 expression is an independent prognostic classifier of patients with GC. TSPAN8 knockdown by siRNA reduced the invasion of GC cell line. The reduction of invasiveness was retrieved by the tetraspanin 8-containing exosome.

CONCLUSION

These results suggest that tetraspanin 8 is involved in tumor progression and is an independent prognostic classifier in patients with GC.

Identification of potential targets for diallyl disulfide in human gastric cancer MGC-803 cells using proteomics approaches

Diallyl disulfide (DADS) is characterized as an effective agent for the prevention and therapy of cancer, however, mechanisms regarding its anticancer effects are not fully clarified. In the present study, we compared the protein expression profile of gastric cancer MGC-803 cells subjected to DADS treatment with that of untreated control cells to explore potential molecules regulated by DADS. Using proteomic approaches, we identified 23 proteins showing statistically significant differences in expression, including 9 upregulated and 14 downregulated proteins. RT-PCR and western blot analysis confirmed that retinoid-related orphan nuclear receptor α (RORα) and nM23 were increased by DADS, whereas LIM kinase-1 (LIMK1), urokinase-type plasminogen activator receptor (uPAR) and cyclin-dependent kinase-1 (CDK1) were decreased. DADS treatment and knockdown of uPAR caused suppression of ERK/Fra-1 pathway, downregulation of urokinase-type plasminogen activator (uPA), matrix metalloproteinase-9 (MMP-9) and vimentin, and upregulation of tissue inhibitor of metalloproteinase-3 (TIMP-3) and E-cadherin, concomitant with inhibition of cell migration and invasion. Moreover, knockdown of uPAR potentiated the effects of DADS on MGC-803 cells. These data demonstrate that downregulation of uPAR may partially be responsible for DADS-induced inhibition of ERK/Fra-1 pathway, as well as cell migration and invasion. Thus, the discovery of DADS-induced differential expression proteins is conducive to reveal unknown mechanisms of DADS anti-gastric cancer.

Oligophrenin-1 is associated with cell adhesion and migration in prostate cancer

OBJECTIVE

We performed Escherichia coli ampicillin secretion trap (CAST) analysis in prostate cancer (PCa) to identify novel biomarkers. We show here that OPHN1, which encodes oligophrenin-1 protein, is upregulated in PCa. OPHN1 was first determined to be one of the genes associated with X-linked mental retardation; however, neither the gene's function nor the link between its expression and survival of patients has been investigated.

METHODS

We investigate the expression of oligophrenin-1 in 141 PCa tissue samples by immunohistochemistry and perform functional analysis using RNA interference.

RESULTS

Immunohistochemical analysis of oligophrenin-1 demonstrated that 60 (43%) PCa cases were positive for oligophrenin-1. Positive oligophrenin-1 expression was significantly correlated with a high Gleason score (p = 0.0198). Furthermore, patients with oligophrenin-1-positive PCa had a worse biochemical recurrence-free survival rate than patients with oligophrenin-1-negative PCa (p = 0.0079). Cell adhesion to fibronectin was significantly reduced in OPHN1 small interfering (si)RNA-transfected LNCaP and PC3 cells in comparison to negative-control siRNA-transfected cells. Knockdown of OPHN1 reduced the expression of ITGA5 and stress fiber formation in LNCaP and PC3 cells.

CONCLUSION

These results suggest that oligophrenin-1 is involved in tumor progression in PCa.

MicroRNA-145 is a potential prognostic factor of scirrhous type gastric cancer

Gastric cancer (GC) is one of the most common malignancies worldwide. In particular, scirrhous type GC is highly metastatic and is characterized clinically by rapid disease progression and poor prognosis. MicroRNAs (miRNAs) play crucial roles in cancer development and progression. We previously demonstrated by microarray analysis that microRNA-145 (miR-145) is one of the more highly expressed miRNAs in scirrhous type GC vs. non-scirrhous types of GC. In the present study, we investigated the role of miR-145 in scirrhous type GC. The expression levels of miR-145 assessed by quantitative RT-PCR were higher in scirrhous type GC tissue samples than in non-scirrhous type GC and corresponding normal tissues. GC patients with high miR-145 expression were at a more advanced tumor stage (P=0.0156) and had more scirrhous type histology (P=0.0054) than those with low miR-145 expression. Furthermore, miR-145 expression was significantly associated with poor prognosis in GC patients (P=0.0438). miR-145 expression was localized in stromal fibroblasts of scirrhous type GC but not in cancer cells. miR-145 was induced by treatment by transforming growth factor-β, and it enhanced the expression of α-smooth muscle actin, a marker of myofibroblasts, in both normal gastric fibroblasts and cancer-associated fibroblasts. These data suggest that miR-145 may contribute to the progression of scirrhous type GC by regulating activation of peri-tumoral fibroblasts.

Overexpression of ZDHHC14 promotes migration and invasion of scirrhous type gastric cancer

Scirrhous type gastric cancer is highly aggressive and has a poorer prognosis than many other types of gastric carcinoma, due to its characteristic rapid cancer cell infiltration and proliferation, extensive stromal fibrosis, and frequent peritoneal dissemination. The aim of the present study was to identify novel prognostic markers or therapeutic targets for scirrhous type gastric cancer. We reviewed a list of genes with upregulated expression in scirrhous type gastric cancer and compared their expression with that in normal stomach from our previous Escherichia coli (E. coli) ampicillin secretion-trap (CAST) analysis. We focused on the ZDHHC14 gene, which encodes zinc finger, DHHC-type containing 14 protein. qRT-PCR analysis of ZDHHC14 in 41 gastric cancer cases revealed that compared to mRNA levels in normal non-neoplastic gastric mucosa, ZDHHC14 mRNA was overexpressed in 27% of gastric cancer tissue samples. The overexpression of ZDHHC14 was significantly associated with depth of tumor invasion, undifferentiated histology and scirrhous pattern. The invasiveness of ZDHHC14-knockdown HSC-44PE and 44As3 gastric cancer cells was decreased in comparison with that of the negative control siRNA-transfected cells, together with downregulation of MMP-17 mRNA. Integrins α5 and β1 were also downregulated in ZDHHC14-knockdown 44As3 cells. Forced expression of ZDHHC14 activated gastric cancer cell migration and invasion in vitro. These results indicate that ZDHHC14 is involved in tumor progression in patients with scirrhous type gastric cancer.

Identification of novel transmembrane proteins in scirrhous-type gastric cancer by the Escherichia coli ampicillin secretion trap (CAST) method: TM9SF3 participates in tumor invasion and serves as a prognostic factor

OBJECTIVE

Scirrhous-type gastric cancer (GC) is highly aggressive and has a poor prognosis due to rapid cancer cell infiltration accompanied by extensive stromal fibrosis. The aim of this study is to identify genes that encode transmembrane proteins frequently expressed in scirrhous-type GC.

METHODS

We compared Escherichia coli ampicillin secretion trap (CAST) libraries from 2 human scirrhous-type GC tissues with a normal stomach CAST library. By sequencing 2,880 colonies from scirrhous CAST libraries, we identified a list of candidate genes.

RESULTS

We focused on the TM9SF3 gene because it has the highest clone count, and immunohistochemical analysis demonstrated that 46 (50%) of 91 GC cases were positive for TM9SF3, which was observed frequently in scirrhous-type GC. TM9SF3 expression showed a significant correlation with the depth of invasion, tumor stage and undifferentiated GC. There was a strong correlation between TM9SF3 expression and poor patient outcome, which was validated in two separate cohorts by immunostaining and quantitative RT-PCR, respectively. Transient knockdown of the TM9SF3 gene by siRNA showed decreased tumor cell-invasive capacity.

CONCLUSION

Our results indicate that TM9SF3 might be a potential diagnostic and therapeutic target for scirrhous-type GC.

MicroRNA-143 regulates collagen type III expression in stromal fibroblasts of scirrhous type gastric cancer

Gastric cancer (GC) is one of the most common malignancies worldwide. In particular, scirrhous type GC is highly metastatic and is characterized clinically by rapid disease progression and poor prognosis. MicroRNAs (miRNAs) play crucial roles in cancer development and progression. In the present study, we identified several miRNAs that are expressed at higher levels in scirrhous type GC than in non-scirrhous type GC by miRNA microarray analysis. Among these, microRNA-143 (miR-143) expression was higher in scirrhous type GC than in non-scirrhous types of GC. In situ hybridization and quantitative RT-PCR analysis showed that miR-143 is expressed by stromal fibroblasts but not by cancer cells. In stromal cells, miR-143 enhanced collagen type III expression in normal gastric fibroblasts and cancer-associated fibroblasts through activation of transforming growth factor-β)/SMAD signaling. Furthermore, high miR-143 expression in GC was associated with worse cancer-specific mortality (P = 0.0141). Multivariate analysis revealed that miR-143 was an independent prognostic factor. Treatment of GC cell lines with 5-aza-2′-deoxycytidine restored the expression of miR-143, and precursor miR-143 caused the inhibition of cancer cell invasion. These data suggest that miR-143 regulates fibrosis of scirrhous type GC through induction of collagen expression in stromal fibroblasts and that miR-143 expression serves as a prognostic marker of GC.

NRD1, which encodes nardilysin protein, promotes esophageal cancer cell invasion through induction of MMP2 and MMP3 expression

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide. In the present study, to identify novel prognostic markers or therapeutic targets for ESCC, we reviewed a list of genes with upregulated expression in ESCC compared with normal esophagus, as identified by our serial analysis of gene expression (SAGE) analysis. We focused on the NRD1 gene, which encodes the nardilysin protein. Quantitative reverse transcription–polymerase chain reaction (qRT-PCR) in 34 ESCC tissue samples revealed that mRNA expression of NRD1 was upregulated in 56% of ESCC tissue samples. Immunohistochemical analysis of nardilysin in 109 ESCC tissue samples demonstrated that 43 (39%) ESCC cases were positive for nardilysin. Nardilysin-positive ESCC cases were more advanced in terms of T classification (P = 0.0007), N classification (P = 0.0164), and tumor stage (P < 0.0001) than nardilysin-negative ESCC cases. Furthermore, nardilysin expression was significantly associated with poorer prognosis (P = 0.0258). Univariate and multivariate analyses revealed that nardilysin expression is an independent prognostic classifier of patients with ESCC. The invasiveness of NRD1-knockdown TE1 and TE5 esophageal cancer cell lines was less than that of the negative control siRNA-transfected cell lines. Expression of MMP2 and MMP3 mRNA was significantly lower in NRD1-knockdown TE5 cells than in negative control siRNA-transfected cells. These results suggest that nardilysin is involved in tumor progression, and is an independent prognostic classifier in patients with ESCC.

Reg IV is a direct target of intestinal transcriptional factor CDX2 in gastric cancer

REG4, which encodes Reg IV protein, is a member of the calcium-dependent lectin superfamily and potent activator of the epidermal growth factor receptor/Akt/activator protein-1 signaling pathway. Several human cancers overexpress Reg IV, and Reg IV expression is associated with intestinal phenotype differentiation. However, regulation of REG4 transcription remains unclear. In the present study, we investigated whether CDX2 regulates Reg IV expression in gastric cancer (GC) cells. Expression of Reg IV and CDX2 was analyzed by Western blot and quantitative reverse transcription–polymerase chain reaction in 9 GC cell lines and 2 colon cancer cell lines. The function of the 5′-flanking region of the REG4 gene was characterized by luciferase assay. In 9 GC cell lines, endogenous Reg IV and CDX2 expression were well correlated. Using an estrogen receptor-regulated form of CDX2, rapid induction of Reg IV expression was observed in HT-29 cells. Reporter gene assays revealed an important role in transcription for consensus CDX2 DNA binding elements in the 5′-flanking region of the REG4 gene. Chromatin immunoprecipitation assays showed that CDX2 binds directly to the 5′-flanking region of REG4. These results indicate that CDX2 protein directly regulates Reg IV expression.

Desmocollin 2 is a new immunohistochemical marker indicative of squamous differentiation in urothelial carcinoma

AIMS

Urothelial carcinoma (UC) with squamous differentiation tends to present at higher stages than pure UC. To distinguish UC with squamous differentiation from pure UC, a sensitive and specific marker is needed. Desmocollin 2 (DSC2) is a protein localized in desmosomal junctions of stratified epithelium, but little is known about its biological significance in bladder cancer. We examined the utility of DSC2 as a diagnostic marker.

METHODS AND RESULTS

We analysed the immunohistochemical characteristics of DSC2, and studied the relationship of DSC2 expression with the expression of the known markers uroplakin III (UPIII), cytokeratin (CK)7, CK20, epidermal growth factor receptor (EGFR), and p53. DSC2 staining was detected in 24 of 25 (96%) cases of UC with squamous differentiation, but in none of 85 (0%) cases of pure UC. DSC2 staining was detected only in areas of squamous differentiation. DSC2 expression was mutually exclusive of UPIII expression, and was correlated with EGFR expression. Furthermore, DSC2 expression was correlated with higher stage (P = 0.0314) and poor prognosis (P = 0.0477).

CONCLUSIONS

DSC2 staining offers high sensitivity (96%) and high specificity (100%) for the detection of squamous differentiation in UC. DSC2 is a useful immunohistochemical marker for separation of UC with squamous differentiation from pure UC.

Upregulation of HOXA10 in gastric cancer with the intestinal mucin phenotype: reduction during tumor progression and favorable prognosis

Gastric cancer (GC) is one of the most common malignancies worldwide. Better knowledge of the changes in gene expression that occur during gastric carcinogenesis may lead to improvements in diagnosis, treatment and prevention. In this study, we screened for genes upregulated in GC by comparing gene expression profiles from microarray and serial analysis of gene expression and identified the HOXA10 gene. The aim of the present study was to investigate the significance of HOXA10 in GC. Immunohistochemical analysis demonstrated that 221 (30%) of 749 GC cases were positive for HOXA10, whereas HOXA10 was scarcely expressed in non-neoplastic gastric mucosa except in the case of intestinal metaplasia. Next, we analyzed the relationship between HOXA10 expression and clinicopathological characteristics. HOXA10 expression showed a significant inverse correlation with the depth of invasion and was observed more frequently in the differentiated type of GC than in the undifferentiated type of GC. HOXA10 expression was associated with GC with the intestinal mucin phenotype and correlated with CDX2 expression. Furthermore, the prognosis of patients with positive HOXA10 expression was significantly better than in the negative expression cases. 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide and wound healing assay revealed that knockdown of HOXA10 in GC cells by short interfering RNA transfection significantly increased viability and motility relative to the negative control, indicating that HOXA10 expression inhibits cell growth and motility. These results suggest that expression of HOXA10 may be a key regulator for GC with the intestinal mucin phenotype.

Relationship between the localization of fibroblast growth factor 9 in prostate cancer cells and postoperative recurrence

BACKGROUND

Fibroblast growth factor 9 (FGF9) enhances cell proliferation and invasiveness in several malignant diseases. The aim of the present study is to investigate the role of FGF9 in postoperative recurrence after radical prostatectomy.

METHODS

Cell viability and invasion of LNCaP cells were assessed using MTT assay and Matrigel invasion assay, respectively, in the presence or absence of treatment with recombinant FGF9. Tissues obtained during a radical prostatectomy in 133 male patients were immunohistochemically stained using anti-FGF9 antibody.

RESULTS

Cell viability and invasion of LNCaP was significantly enhanced by treatment with recombinant FGF9. Immunohistochemical staining detected FGF9-positive cells in 20 samples. The prevalence of FGF9-positive cells in cases with a Gleason score of 8 or higher was 34.2%, which was significantly higher than that in those with Gleason scores of 7 or lower (7.3%, P=0.0003), respectively. The 3-year biochemical relapse-free survival rate was 17.5% in cases with FGF9-positive cells, which was significantly lower than that in cases in which FGF9-positive cells were not detectable (75.5%, P < 0.0001).

CONCLUSIONS

These results indicate that FGF9 can stimulate proliferation and invasion in prostate cancer cells, thus FGF9 could be a candidate of a predictive factor for recurrence after radical prostatectomy.

Serum olfactomedin 4 (GW112, hGC-1) in combination with Reg IV is a highly sensitive biomarker for gastric cancer patients

Gastric cancer (GC) is 1 of the most common human cancers. Early detection remains the most promising approach to improving long-term survival of patients with GC. We previously performed Serial Analysis of Gene Expression (SAGE) on 4 primary GCs and identified several GC-specific genes including Reg IV. Of these genes, olfactomedin 4 (OLFM4, also known as GW112 or hGC-1) is a candidate gene for cancer-specific expression. In this study, we examined the expression of olfactomedin 4 in human GC by immunohistochemistry. We also assessed serum olfactomedin 4 levels in GC patients by enzyme-linked immunosorbent assay. 94 (56%) of 167 GC cases were positive for olfactomedin 4 by immunostaining. Olfactomedin 4 staining was observed more frequently in stage I/II cases than in stage III/IV cases. The serum olfactomedin 4 concentration in presurgical GC patients (n = 123, mean +/- SE, 36.3 +/- 3.5 ng/mL) was significantly higher than that in healthy individuals (n = 76, 16.6 +/- 1.6 ng/mL). In patients with stage I GC, the sensitivity of serum olfactomedin 4 (25%) and Reg IV (35%) was superior to that of CA19-9 (5%) or CEA (3%). Furthermore, in patients with stage I GC, the combination of olfactomedin 4 and Reg IV elevated the diagnostic sensitivity to 52%. These results suggest that serum olfactomedin 4 is a useful marker for GC and its measurement alone or in combination with Reg IV has utility in the early detection of GC.

Reg IV is an independent prognostic factor for relapse in patients with clinically localized prostate cancer

Regenerating islet-derived family, member 4 (REG4, which encodes Reg IV) is a candidate marker for cancer and inflammatory bowel disease. We investigated the potential prognostic role of Reg IV immunostaining in clinically localized prostate cancer (PCa) after radical prostatectomy. Immunohistochemical staining of Reg IV was performed in 98 clinically localized PCa tumors obtained during curative radical prostatectomy. Intestinal and neuroendocrine differentiation was investigated by MUC2 and chromogranin A immunostaining, respectively. The prognostic significance of immunohistochemical staining for these factors on prostate-specific antigen (PSA)-associated recurrence was assessed by Kaplan-Meier analysis and a Cox regression model. Phosphorylation of the epidermal growth factor receptor (EGFR) by Reg IV was analyzed by Western blot. In total, 14 (14%) of the 98 PCa cases were positive for Reg IV staining. Reg IV positivity was observed frequently in association with MUC2 (P = 0.0182) and chromogranin A positivity (P = 0.0012). Univariate analysis revealed that Reg IV staining (P = 0.0004), chromogranin A staining (P = 0.0494), Gleason score (P < 0.0001) and preoperative PSA concentration (P = 0.0167) were significant prognostic factors for relapse-free survival. Multivariate analysis indicated that Reg IV staining (P = 0.0312), Gleason score (P = 0.0014) and preoperative PSA concentration (P = 0.0357) were independent predictors of relapse-free survival. In the LNCaP cell line, EGFR phosphorylation was induced by the addition of Reg IV-conditioned medium. These results suggest that Reg IV expression is an independent prognostic indicator of relapse after radical prostatectomy.

Gene expression profiling with microarray and SAGE identifies PLUNC as a marker for hepatoid adenocarcinoma of the stomach

Gastric cancer is one of the most common malignancies worldwide. In this study, we screened for genes upregulated in gastric cancer by comparing gene expression profiles from serial analysis of gene expression and microarray and identified the palate, lung, and nasal epithelium carcinoma-associated protein (PLUNC) gene. Immunostaining for PLUNC in 140 gastric cancer cases revealed strong and extensive staining of PLUNC in hepatoid adenocarcinoma of the stomach, whereas 7% of conventional gastric cancer cases showed focal immunostaining of PLUNC. Gastric hepatoid adenocarcinoma is an extrahepatic tumor characterized by morphologic similarities to hepatocellular carcinoma. To investigate the utility of PLUNC immunostaining in the diagnosis of gastric hepatoid adenocarcinoma, six cases of gastric hepatoid adenocarcinoma (six primary tumors and two associated liver metastases) were studied further. PLUNC staining was observed in all six primary hepatoid adenocarcinomas. PLUNC staining was observed in both the hepatoid adenocarcinoma and tubular/papillary adenocarcinoma components of primary tumors, although PLUNC staining was preferentially localized in tubular/papillary adenocarcinoma components. Staining of PLUNC was also detected in both liver metastases. PLUNC staining was not observed in 52 cases of primary hepatocellular carcinoma or in normal adult or fetal liver. These results indicate that PLUNC is a novel marker that distinguishes gastric hepatoid adenocarcinoma from primary hepatocellular carcinoma.

Synthesis of 3-(1H-benzimidazol-2-yl)-5-isoquinolin-4-ylpyrazolo[1,2-b]pyridine, a potent cyclin dependent kinase 1 (CDK1) inhibitor

The novel compound 3-(1H-benzimidazol-2-yl)-5-isoquinolin-4-ylpyrazolo[1,2-b]pyridine was discovered to be a potent CDK1 inhibitor. Described here is the chemistry for its synthesis, including Pd(II) catalyzed Stille coupling reaction and sulfur(0) induced benzimidazole formation. Its effects on VEGFR-2 kinase activity and tumour cell proliferation are also described.

Reg IV is a serum biomarker for gastric cancer patients and predicts response to 5-fluorouracil-based chemotherapy

Regenerating gene family, member 4 (Reg IV), a secreted protein, is overexpressed in several cancers, including gastric cancer (GC). In the present study, we measured Reg IV levels in sera from patients with GC by enzyme-linked immunosorbent assay. We also examined the effect of forced Reg IV expression on the apoptotic susceptibility to 5-fluorouracil (5-FU). Forced expression of Reg IV inhibited 5-FU-induced apoptosis. Induction of Bcl-2 and dihydropyrimidine dehydrogenase was involved in inhibition of apoptosis. Among 36 GC patients treated with a combination chemotherapy of low-dose 5-FU and cisplatin, all 14 Reg IV-positive patients showed no change or disease progression. The serum Reg IV concentration was similar between healthy individuals (mean+/-s.e., 0.52+/-0.05 ng/ml) and patients with chronic-active gastritis (0.36+/-0.09 ng/ml). However, the serum Reg IV concentration in presurgical GC patients was significantly elevated (1.96+/-0.17 ng/ml), even at stage I. The diagnostic sensitivity of serum Reg IV (36.1%) was superior to that of serum carcinoembryonic antigen (11.5%) or carbohydrate antigen 19-9 (13.1%). These results indicate that expression of Reg IV is a marker for prediction of resistance to 5-FU-based chemotherapy in patients with GC. Serum Reg IV represents a novel biomarker for GC.

High-risk human papillomavirus type 16 E7 oncogene associates with Cdc25A over-expression in oral squamous cell carcinoma

Cells expressing high-risk human papillomavirus (HPV) E7 protein display impaired checkpoint control after DNA damage and exhibit elevated rates of mutagenesis. Repression of HPV E7 expression results in the subsequent accumulation of hypophosphorylated retinoblastoma protein and repression of the Cdc25A genes. No study has been conducted to elucidate the role of Cdc25A in the development and progression of human oral carcinomas. To confirm Cdc25A protein expression together with HPV, immunohistochemistry, Western blotting, polymerase chain reaction (PCR), and reverse transcriptase (RT)-PCR were performed using various histological subtypes of oral carcinomas. Cdc25A protein was localized predominantly in the cell nuclei in carcinomas, and high expression was found in 54% of primary tumors. HPV-16 E7 was not found in non-neoplastic oral tissues, whereas it was observed in eight (36%) of 22 oral carcinomas. We found a significant correlation between Cdc25A over-expression and HPV-16 E7 positive carcinomas. There was a strong positive correlation between Cdc25A over-expression and tumor size and TNM stage. This study suggests that Cdc25A is likely to be an important mediator in the progression of oral tumors, and HPV-16 E7 may be a sensitive indicator of the involvement of viral oncogenes in oral carcinogenesis.

Synthesis of 2-amino-4-(7-azaindol-3-yl)pyrimidines as cyclin dependent kinase 1 (CDK1) inhibitors

A novel series of 2-amino-4-(7-azaindol-3-yl)pyrimidines was discovered as cyclin dependent kinase 1 (CDK1) inhibitors. The core structure was synthesized via Pd(II) catalyzed coupling reaction. A number of analogues showed good potency for CDK1 and exhibited cellular antiproliferation activity. The structure-activity relationship is described.

Synthesis and evaluation of N-acyl sulfonamides as potential prodrugs of cyclin-dependent kinase inhibitor JNJ-7706621

A novel prodrug strategy for cyclin-dependent kinase inhibitor JNJ-7706621 has been explored. Through N-acylation of a sulfonamide substituent, tails containing different solubilizing groups (amino, carboxyl, alkoxyl, and hydroxyl) were attached to JNJ-7706621. Most of the prodrugs exhibited good aqueous solubility and the N-acyl groups on the sulfonamide were metabolically cleaved to generate active drug in rat PK study.

Down-regulation of the claudin-18 gene, identified through serial analysis of gene expression data analysis, in gastric cancer with an intestinal phenotype

Gastric cancer (GC) is one of the most common malignancies worldwide. Genes whose expression is down-regulated in GC may be tumour suppressor genes. In the present study, genes with decreased expression in GC were screened for by serial analysis of gene expression (SAGE) data analysis and reverse transcription (RT)-polymerase chain reaction (PCR), and CLDN18 (encoding claudin-18) was identified. Quantitative RT-PCR revealed that expression of CLDN18 was down-regulated in 13 (56.5%) of 23 GCs. Immunostaining showed that normal gastric mucosa and Paneth cells of the duodenum expressed claudin-18 on cell membranes. Expression of claudin-18 was reduced in several intestinal metaplasias of the stomach. Of 20 samples of gastric adenoma, 18 (90.0%) showed decreased claudin-18 expression. Down-regulation of claudin-18 was observed in 84 of 146 GCs (57.5%) and correlated with poor survival in 65 advanced GCs (p = 0.0346). In addition, expression of the gastric and intestinal phenotypes of GC was examined by immunostaining for MUC5AC, MUC6, MUC2, and CD10. Of 38 GCs showing only the intestinal phenotype, down-regulation of claudin-18 was observed in 28 (73.7%), whereas in the remaining 108 GC cases, down-regulation of claudin-18 was observed in 56 (51.9%) (p = 0.0224). These results indicate that claudin-18 is a good marker of poor survival in GC. Down-regulation of claudin-18 may be involved in GCs with an intestinal phenotype, and may be an early event in gastric carcinogenesis.

Differential expression of claudin-2 in normal human tissues and gastrointestinal carcinomas

Claudins are involved in the formation of tight junctions in epithelial and endothelial cells. Claudins form a family of 24 members displaying organ- and tissue-specific patterns of expression. In the present study, we evaluated the specificity of the claudin-2 expression in various normal human tissues and gastrointestinal cancers by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry. In 14 various normal tissues, claudin-2 mRNA was expressed in the kidney, liver, pancreas, stomach, and small intestine; the highest level of which was detected in the kidney. Colorectal cancers (CRCs) expressed claudin-2 mRNA at high levels. Immunohistochemical analysis of claudin-2 in 146 gastric cancers (GCs) and 99 CRCs demonstrated claudin-2 expression in 2.1% of GCs and 25.3% of CRCs, respectively. There was no obvious correlation between claudin-2 expression and clinicopathological parameters of CRCs. These results suggest that the expression of claudin-2 may involve organ specificity, and increased expression of claudin-2 may participate in colorectal carcinogenesis.

Expression and localization of Reg IV in human neoplastic and non-neoplastic tissues: Reg IV expression is associated with intestinal and neuroendocrine differentiation in gastric adenocarcinoma

Regenerating islet-derived family, member 4 (Reg IV) is a candidate marker for cancer and inflammatory bowel disease. In the present study, immunohistochemical analysis of Reg IV was performed in various human neoplastic (n = 289) and non-neoplastic tissues. In the stomach, foveolar epithelium was negative for Reg IV, whereas goblet cells of intestinal metaplasia and neuroendocrine cells at the base of intestinal metaplasia expressed Reg IV. Neuroendocrine cells of the small intestine and colon showed strong expression of Reg IV, whereas goblet cells of the small intestine and colon showed weak or no expression of Reg IV. Insulin-producing beta cells of the endocrine pancreas were positive for Reg IV. Among 143 gastric adenocarcinomas, Reg IV expression was detected in 42 (29.4%) and was associated with both the intestinal mucin phenotype and neuroendocrine differentiation. No association was found between Reg IV expression and clinical characteristics such as tumour stage and patient prognosis. Of 36 colorectal adenocarcinomas, 13 (36.1%) were positive for Reg IV, which was associated with tumour stage (p = 0.0379, Fisher's exact test). Expression of Reg IV was detected in 14 (93.3%) of 15 colorectal carcinoid tumours. Reg IV expression was also detected in 5 (21.7%) of 23 ductal adenocarcinomas of the pancreas. In contrast, lung cancers (n = 30) and breast cancers (n = 30) did not express Reg IV. This is the first immunohistochemical analysis of the expression and distribution of Reg IV protein in human tumours. These data suggest that Reg IV is expressed by gastrointestinal and pancreatic tumours, including adenocarcinomas and carcinoid tumours, and that Reg IV is associated with intestinal and neuroendocrine differentiation of the stomach and gastric carcinoma.

Down-regulatory effects of glycyrrhizin on expression of cyclin-dependent kinase 1 gene promoter

AIM: To investigate the regulatory effects of the glycyrrhizin on the expression of cyclin-dependent kinase 1 (CDK1) gene promoter as well as its molecular biological mechanisms.

METHODS: The report gene expression vector pCAT3-CDK1-P was transfected into the HepG2 cell line, and then stimulated with glycyrrhizin. The HepG2 cells transfected with pCAT3-basic was used as a negative control. The expression level of chloramphenicol acetyltransferase (CAT) in the transfected HepG2 cells was detected by enzyme-linked immunoassay (ELISA) after 24 h.

RESULTS: pCAT3-CDK1-P activated the expression of CAT in HepG2 cells, while the glycyrrhizin inhibited it. The activity of CAT in pCAT3-CDK1-P transfected cells without stimulation was 9.3 times as high as that in pCAT3-CDK1-P transfected cells stimulated with glycyrrhizin, and 12.4 times as high as that in pCAT3-basic transfected cells.

CONCLUSION: Glycyrrhizin can down-regulate the expression of CDK1 gene promoter, and further down-regulate the expression of CDK1 gene.

TheIn vitroandIn vivoEffects of JNJ-7706621: A Dual Inhibitor of Cyclin-Dependent Kinases and Aurora Kinases

Modulation of aberrant cell cycle regulation is a potential therapeutic strategy applicable to a wide range of tumor types. JNJ-7706621 is a novel cell cycle inhibitor that showed potent inhibition of several cyclin-dependent kinases (CDK) and Aurora kinases and selectively blocked proliferation of tumor cells of various origins but was about 10-fold less effective at inhibiting normal human cell growth in vitro. In human cancer cells, treatment with JNJ-7706621 inhibited cell growth independent of p53, retinoblastoma, or P-glycoprotein status; activated apoptosis; and reduced colony formation. At low concentrations, JNJ-7706621 slowed the growth of cells and at higher concentrations induced cytotoxicity. Inhibition of CDK1 kinase activity, altered CDK1 phosphorylation status, and interference with downstream substrates such as retinoblastoma were also shown in human tumor cells following drug treatment. Flow cytometric analysis of DNA content showed that JNJ-7706621 delayed progression through G1 and arrested the cell cycle at the G2-M phase. Additional cellular effects due to inhibition of Aurora kinases included endoreduplication and inhibition of histone H3 phosphorylation. In a human tumor xenograft model, several intermittent dosing schedules were identified that produced significant antitumor activity. There was a direct correlation between total cumulative dose given and antitumor effect regardless of the dosing schedule. These results show the therapeutic potential of this novel cell cycle inhibitor and support clinical evaluation of JNJ-7706621.

Association of expression of receptor for advanced glycation end products and invasive activity of oral squamous cell carcinoma

OBJECTIVES

The receptor for advanced glycation end products (RAGE) is a newly recognized factor regulating cancer cell invasion and metastasis. Nevertheless, the involvement of RAGE in the development and progression of oral squamous cell carcinomas has not been elucidated. This study investigated the expression of RAGE in ten oral squamous cell carcinoma cell lines including primary and metastatic cell lines and its association with invasion and metastasis.

METHODS

Reverse transcriptase-polymerase chain reaction, antisense phosphorothioate (S)-oligodeoxynucleotide assay, preparation of antibody, immunohistochemical staining, immunoblot analysis, migration assay, in vitro invasion assay, and wound-healing assay were used.

RESULTS

RAGE protein expression of metastatic cancer cells treated with RAGE antisense S-oligodeoxynucleotide was significantly reduced compared to that of sense S-oligodeoxynucleotide-treated cells. The migration assay showed that invasive activity was significantly reduced in metastatic cancer cells treated with RAGE antisense S-oligodeoxynucleotide. Similarly, during invasion assays, numbers of invading cells were also reduced with the addition of RAGE antisense S-oligodeoxynucleotide-treated cells. A wound-healing assay showed that only a few RAGE antisense S-oligodeoxynucleotide-treated cancer cells migrated into the scraped area, whereas sense S-oligodeoxynucleotide-treated cells showed many budding nests in the scraped area of the metastatic cell lines. Immunohistochemically, oral squamous cell carcinoma cells in the tumour mesenchymal border were often immunopositive, whereas basal cells in the normal mucosa were scarcely positive.

CONCLUSIONS

These results suggest that RAGE expression appears to be closely associated with the invasiveness of oral squamous cell carcinoma and represents a promising candidate for assessing the future therapeutic potential in treating patients with oral carcinoma.

The therapeutic potential of targeting the cell cycle

With the advent of modern molecular genetics, molecular biology and biochemistry has come a revolution in oncology drug discovery research. We are rapidly developing an increased understanding in the mechanisms driving cellular proliferation, transformation, differentiation and metastasis. The hope is that from these advances will emerge novel therapeutics that are more specific, more efficacious and less toxic than their predecessors. Uncontrolled proliferation is a hallmark of a cancer cell. Over the past two decades it has become increasingly clear that molecules that directly control cell cycle progression accumulate defects during tumourigenesis. These defects can result in the loss of checkpoint control and/or the inappropriate activation of the 'drivers' of cell cycle progression, the cyclin-dependent kinases (cdks). This review will describe the recent advances in our understanding of cell cycle regulation and its relation to tumourigenesis, and highlight the potential for the development of novel anticancer therapeutics.

Histone H3 acetylation is associated with reduced p21(WAF1/CIP1) expression by gastric carcinoma

Histone acetylation appears to play an important role in transcriptional regulation. Inactivation of chromatin by histone deacetylation is involved in the transcriptional repression of several tumour suppressor genes, including p21(WAF1/CIP1). However, the in vivo status of histone acetylation in human cancers, including gastric carcinoma, is not well understood. This study shows that histone H3 in the p21(WAF1/CIP1) promoter region is hypoacetylated and that this hypoacetylation is associated with reduced p21(WAF1/CIP1) expression in gastric carcinoma specimens. Chromatin immunoprecipitation assays revealed that histone H3 was hypoacetylated in the p21(WAF1/CIP1) promoter and coding regions in 10 (34.5%) and 10 (34.5%) of 29 gastric carcinoma specimens, respectively. Hypoacetylation of histone H4 in the p21(WAF1/CIP1) promoter and coding regions was observed in 6 (20.7%) and 16 (55.2%) of 29 gastric carcinoma specimens, respectively. p21(WAF1/CIP1) mRNA levels were associated with histone H3 acetylation status in the p21(WAF1/CIP1) promoter region (p = 0.047) but not p53 mutation status (p = 0.460). In gastric carcinoma cell lines, expression of p21(WAF1/CIP1) protein was induced by trichostatin A, a histone deacetylase inhibitor. This induction was associated with hyperacetylation of histone H3 in the p21(WAF1/CIP1) promoter region. Hyperacetylation of histone H4 in the p21(WAF1/CIP1) promoter region did not appear to be associated with increased expression. Induction of p21(WAF1/CIP1) protein expression was associated with hyperacetylation of histones H3 and H4 in the p21(WAF1/CIP1) coding region. Expression of a dominant-negative mutant of p53 reduced expression of p21(WAF1/CIP1) protein. Histone H4 acetylation in both the promoter and coding regions of the p21(WAF1/CIP1) gene in cells expressing dominant-negative p53 was less than half of that in cells expressing wild-type p53, whereas histone H3 acetylation in both the promoter and coding regions was slightly reduced (by approximately 20%) in cells expressing the dominant-negative p53. These findings provide evidence that alteration of histone acetylation occurs in human cancer tissue specimens such as those from gastric carcinoma.