Protocadherin 17 Promoter Research Articles

Quantitation Analysis of PCDH10 Methylation in Adolescent Idiopathic Scoliosis Using Pyrosequencing Study.

A retrospective and comparative study. To evaluate the difference of DNA methylation in protocadherin10 (PCDH10) genes between adolescent idiopathic scoliosis (AIS) and normal controls, and to assess the association between DNA methylation and the etiology of AIS. The PCDH10 gene showed abnormal expression in AIS. However, the mechanism was still unclear. DNA methylation was an important epigenetic mechanism at the interface between genetics and environmental phenotype, seeming to be a suitable epigenetic mark for the abnormal expression of PCDH10 in AIS. There were 50 AIS patients and 50 healthy controls included in the study. The peripheral blood sample of each participant was taken. The pyrosequencing assay was used to assess the methylation status of PCDH10 promoter and real time PCR (RT-PCR) was used to detect the PCDH10 gene expression. The comparison analysis was performed using independent t test and 2-tailed Pearson coefficients was calculated for the correlation analysis. The average methylation level was 4.32 ± 0.73 in AIS patients and 3.14 ± 0.97 in healthy controls (P < 0.001). The PCDH10 gene expression was 0.23 ± 0.04 in AIS patients and 0.36 ± 0.08 in normal controls (P < 0.0001). Statistically significant linear correlation was found between PCDH10 gene methylation level and Cobb angle of major curve (P < 0.001). Besides, a significant negative correlation between PCDH10 methylation and PCDH10 gene expression was found (P < 0.001). AIS patients were associated with high DNA methylation level and low gene expression of PCDH10 gene rather than normal controls. The high methylation level indicated high Cobb angle of major curves in AIS. The abnormal DNA methylation may widely exist and serve as a potential mechanism for AIS. 3.

Aberrant promoter methylation reduced the expression of protocadherin 17 in nasopharyngeal cancer.

This study aimed to explore the underlying mechanism of protocadherin 17 (PCDH17) downregulated in nasopharyngeal cancer (NPC). NPC tumor and adjacent tissue samples were collected from NPC patients who received therapy in the Chinese PLA General Hospital. Meanwhile, a normal epithelial cell lines NP96 and 6 NPC and cell lines C666-1, CEN1, CEN2, HNE1, HEN2, and HONE1 were prepared. Then, the expression level of PCDH17 and the methylation level of PCDH17 promoter in both tissues samples and cell lines were determined using the PCR method. Moreover, PCDH17 was overexpressed in CNE2 and HONE1 using Lipo2000. Following this, the proliferation and apoptosis of CNE2 and HONE1 were assessed using MTT and flow cytometry. The expression of PCDH17 was significantly downregulated in NPC tissues compared with the adjacent tissues as well as in the NPC cell lines compared with the normal NP96 cells. Overexpressed PCDH17 could significantly inhibit the proliferation of CNE2 and HONE1 cells but obviously promote the apoptosis of these two cell lines. Aberrant hypermethylation in the promoter might be the explanation of PCDH17 downregulated in PCDH17 and promoted the development of NPC.

Quantitative analysis of protocadherin 10 promoter methylation in peripheral blood of patients with gastric cancer by real-time and methylation specific polymerase techniques and its significance

Objective To investigate protocadherin 10 (PCDH10) methylation at promoter 5’-cytosine-phosphoric acid-guanine motif (CpG) island as a tool for non-invasive diagnosis and prognosis evaluation of primary gastric cancer. Methods Real-time fluorescent quantitative methylation specific polymerase chain reaction (Real-time MSP) technique was used for detection of PCDH10 promoter methylation in both tissue and serum specimens from 202 gastric cancer (GC), 52 gastric epithelial dysplasia, and 68 chronic gastritis, as well as 120 healthy human serum specimens. The relationship between PCDH10 methylation with clinicopathological parameters and prognosis was analyzed. Results The incidence of PCDH10 methylation in gastric cancer tissues (80.2%, 162/202) was significantly higher than that in paired adjacent tissues (26.7%, 54/202), gastric epithelial dysplasia (23.1%, 12/52) and chronic gastritis specimens (14.7%, 10/68) (all P=0.000). Detectable rate of PCDH10 methylation in serum specimens was in good agreement with that in the paired tumor tissues, with the Aζ value being 0.862 (P=0.000). The level of PCDH10 methylation in serum was closely correlated to age at diagnosis (P=0.018), H. pylori (Hp) infection (P=0.000), tumor size (P=0.000), tumor differentiation (P=0.002), lymphatic invasion (P=0.000), venous invasion (P=0.007), invasion depth (P=0.000), lymphatic metastasis (P=0.000), distant metastasis (P=0.015), clinical stages (P=0.000) and poor prognosis (P=0.000), but not with gender (P=0.435), tumor site (P=0.458) and growth pattern (P=0.435). Conclusion PCDH10 methylation plays an important role in the tumorigenesis and development of gastric cancer. Key words: Gastric cancer; Protocadherin 10; DNA methylation; Early diagnosis; Prognosis

PCDH10 gene inhibits cell proliferation and induces cell apoptosis by inhibiting the PI3K/Akt signaling pathway in hepatocellular carcinoma cells.

Protocadherin10 (PCDH10), a member of the non-clustered protocadherin (PCDH) family, functions as a tumor-suppressor gene in many cancers. Previous studies have demonstrated that the expression of PCDH10 was noticeably downregulated in the tissue and cells of hepatocellular carcinoma (HCC), when compared to those in normal liver tissue. The decreased PCDH10 expression in HCC was correlated with the aberrant methylation status of PCDH10 promoter. However, the biological functions and molecular mechanism of PCDH10 in HCC have yet to be elucidated. The aim of the present study was to identify the biological function and mechanisms of PCDH10 in HCC. Quantitative real-time polymerase chain reaction was used to detect the expression of PCDH10 in HCC cells with decreased expression of PCDH10 which were transfected with plasmid pcDNA3.1-PCDH10 or pcDNA3.1-vector using Lipofectamine 2000. The biological effects of PCDH10 in HCC cells were detected by CCK-8, colony formation and flow cytometric assays. Western blot and co-immunoprecipitation (Co-IP) assays were performed to explore the mechanism of PCDH10 in HCC cells. PCDH10 expression was downregulated in the HCC cells (HepG2, HuH7, HuH1, and SNU387) when compared to the normal liver cells (L02). Upregulation of PCDH10 inhibited cell proliferation and induced cell apoptosis in the HCC cells. More importantly, we revealed that PCDH10 inhibited the PI3K/Akt signaling pathway thus carrying out its suppressive function in HCC. This study provides insights into the tumorigenesis and progression of HCC, and puts forward the novel hypothesis that PCDH10 could be a new biomarker for HCC, or that combined with other molecular markers could increase the specificity and sensitivity of diagnostic tests for HCC. Restoration of PCDH10 could be a valuable therapeutic target for HCC.

Protocadherin-10 acts as a tumor suppressor gene, and is frequently downregulated by promoter methylation in pancreatic cancer cells.

Protocadherin-10 (PCDH10), a member of non-clustered protocadherin family which plays important roles in calcium-dependent cell-cell signal transduction and adhesion. PCDH10 functions as a tumor suppressor gene and its expression is downregulated by promoter methylation in many malignances. In the present study, we explored PCDH10 expression and promoter methylation status, and its biological effects in pancreatic cancer cells, and furthermore, we explored the mechanism of PCDH10 preliminary in pancreatic cancer cells. the mRNA level of PCDH10 was detected by semi-quantitative reverse transcription PCR and promoter methylation status examined by methylation-specific PCR in the pancreatic cancer cells (Capan-1, Panc-1, AsPC-1 and BxPC-3) as well as the human normal pancreatic ductal epithelial cells HPDE6-C7 which was used as a control. The human pancreatic cells were transfected with plasmid pcDNA3.1-PCDH10 or pcDNA3.1 by lipofectamine 2000. The biological function of PCDH10 in pancreatic cancer cells was determined by CCK-8 assay, colony formation assay, flow cytometry, Transwell invasion assay and wound-healing assay. The levels of apoptosis related proteins were examined by western blotting. PCDH10 expression was obviously downregulated in the pancreatic cancer cells (Capan-1, Panc-1, BxPC-3) compared to the normal pancreatic ductal epithelial cells. PCDH10 promoter methylation was observed in the two pancreatic cancer cells Capan-1 and BxPC-3,and the expression of PCDH10 could be restored after treating with 5-aza-2'-deoxycytidine and trichostatin A in the two cell types. Overexpression of PCDH10 can inhibit the proliferation, migration, invasion ability of pancreatic cancer cells and induce apoptosis. Ectopic expression of PCDH10 could increase the levels of PARP, caspase-3, caspase-9 and decrease the level of bcl-2, AKT and p-AKT. PCDH10 acts as a tumor suppressor gene, and is frequently down-regulated by promoter methylation in pancreatic cancer cells. PCDH10 may induce cancer cell apoptosis via the AKT pathway.

Se-Allylselenocysteine induces autophagy by modulating the AMPK/mTOR signaling pathway and epigenetic regulation of PCDH17 in human colorectal adenocarcinoma cells.

Selenium (Se)-conjugated compounds have been established as anti-carcinogenic compounds. The use of chemicals as cancer chemotherapeutic agents to induce programmed cell death (PCD) involves genetic and epigenetic modifications. In this study, we investigated the underlying molecular mechanisms of Se-allylselenocysteine (ASC)-induced PCD and protocadherin 17 (PCDH17) expression in HT-29 cells. Cell viability analysis indicated that the ability of ASC to induce cancer cell death was greater than that of Se-methylselenocysteine in colorectal cancer cells. ASC also decreased global DNA methylation levels via downregulation of DNA methyltransferase 1 expression. The autophagic cell death is the cause in ASC-induced cytotoxicity that was inhibited by pretreatment with autophagy inhibitor. At the molecular level, ASC induced PCDH17 expression through decreased PCDH17 promoter hypermethylation. PCDH17 is also an important role in ASC-induced autophagy by HT-29 transfected with PCDH17 shRNA or expression plasmid. Our western blot analysis showed that ASC significantly induced autophagy via the AMPK/mTOR pathway that was also regulated PCDH17 expression. Additionally, we used the HT-29 tumor xenograft models to confirm the ability of ASC inhibited tumor growth. These results reveal that ASC is an effective inducer of autophagy through regulating the AMPK/mTOR and PCDH17 expression via epigenetic modification.

Evaluating the clinical feasibility: The direct bisulfite genomic sequencing for examination of methylated status of protocadherin10 (PCDH10) promoter to predict the prognosis of gastric cancer.

To elucidate the clinical significance of the methylated status of CpG site count of PCDH10 promoter in the survival prediction in gastric cancer (GC). In the previous study, we demonstrated that the methylated CpG site count was significantly associated with the overall survival (OS) of GC patients by using the bisulfite genomic sequencing (BGS) with no less than five clones per sample. It was so complex and expensive for patients to undergo the BGS clones. In this study, we detected the different CpG site counts (hypermethylated and hypomethylated) of PCDH10 DNA promoter in GC samples of 471 patients by directly bisulfite genomic sequencing (D-BGS) without any clone. Furthermore, we evaluated the relationships between the methylated status of PCDH10 promoter and OS. Two hundred and fifty-seven of 471 (54.6%) GC patients were identified to present with PCDH10 promoter methylation by D-BGS. Patients who presented with 5 or more methylated CpG site counts of PCDH10 promoter had significantly poorer prognosis than patients who with less than 5 methylated CpG site counts of PCDH10 promoter (p= 0.039). With the multivariate survival analysis, we demonstrated that T stage, N stage and the hypermethylated CpG site counts of PCDH10 DNA promoter were the independent predictors of OS of GC patients. In addition, the hypermethylated CpG site counts of PCDH10 DNA promoter had smaller Akaike information criterion (AIC) and Bayesian information criterion (BIC) values than the other two independent predictors of the OS, indicating the hypermethylated CpG site counts of PCDH10 DNA promoter as the best prognostic predictor of GC. Our present findings suggested that the hypermethylated CpG site counts of PCDH10 DNA promoter for evaluating the prognosis of GC was reasonable by using the D-BGS.

Prognostic signature of protocadherin 10 methylation in curatively resected pathological stage I non-small-cell lung cancer.

Although curative resection is the current treatment of choice for localized non-small-cell lung cancer (NSCLC), patients show a wide spectrum of survival even after complete resection of pathological stage I NSCLC. Thus, identifying molecular biomarkers that help to accurately select patients at high risk of relapse is an important key to improving the treatment strategy. The purpose of this study was to evaluate the prognostic signature of protocadherin 10 (PCDH10) promoter methylation in curatively resected pathological stage I NSCLC. Using methylation-specific polymerase chain reaction assays, methylation of PCDH10 promoter was assessed in cancer tissues of 109 patients who underwent curative resection of pathological stage I NSCLC. Associations between PCDH10 methylation status and disease outcome was analyzed. PCDH10 promoter methylation was detected in 46/109 patients (42.2%). Patients with methylated PCDH10 showed significantly worse recurrence-free, overall, and disease-specific survival compared with those without methylation (P < 0.0001, P = 0.0004, P = 0.0002, respectively). Multivariate Cox proportional hazard regression analysis revealed that adjusted hazard ratios of methylated PCDH10 were 5.159 for recurrence-free, 1.817 for overall, and 5.478 for disease-specific survival (P = 0.0005, P = 0.1475, P = 0.0109, respectively). The pattern of recurrence was not significantly different between patients with and without PCDH10 methylation (P = 0.5074). PCDH10 methylation is a potential biomarker that predicts a poor prognosis after curative resection of pathological stage I NSCLC. Assessment of PCDH10 methylation status might assist in patient stratification for determining an appropriate adjuvant treatment and follow-up strategy.

Clinical Significance of the Methylated Cytosine-Phosphate-Guanine Sites of Protocadherin-10 Promoter for Evaluating the Prognosis of Gastric Cancer

Protocadherin-10 (PCDH10) has been identified as a tumor suppressor gene in multiple carcinomas. In this study, we intended to elucidate the clinical applicability of the methylation of CpG sites of PCDH10 promoter for prognostic prediction in gastric cancer (GC). Qualitative and quantitative detections of PCDH10 promoter methylation were performed with methylation-specific polymerase chain reaction (MSP) and bisulphite genomic sequencing, respectively. The methylated statuses of 27 cytosine-phosphate-guanine (CpG) sites in PCDH10 promoter were detected in a series of 458 GC tissues to supply precise information of prognostic prediction. Associations between molecular, clinicopathologic, and survival data were analyzed. Protocadherin-10 promoter methylation was found in 91.92% in all patients. Gastric cancer patients with 5 or more methylated CpG sites of PCDH10 promoter was significantly associated with poorer survival (p= 0.038). Meanwhile, methylation of combined CpG (-115,-108,-13, and+3) sites was also identified to provide elaborate survival discrimination for GC patients (p= 0.044). On multivariate survival analysis, methylation of combined CpG (-115,-108,-13, and+3) sites (hazard ratio [HR]= 1.255; p= 0.049) was identified to be an independent prognostic indicator of GC, as were N stage and T stage. Additionally, the methylation of combined CpG (-115,-108,-13, and+3) sites had smaller Akaike information criterion (AIC) and Bayesian information criterion (BIC) values than the other 2 independent predictors of the survival. Ultimately, we demonstrated that the methylation of combined CpG (-115,-108,-13, and+3) sites was negatively associated with PCDH10 expression in GC tissues. The methylated CpG sites of PCDH10 promoter had significant applicability for clinical evaluation of the prognosis of GC.

Protocadherin 17 promoter methylation in tumour tissue from patients with bladder transitional cell carcinoma

To investigate the clinical significance of protocadherin 17 (PCDH17) promoter methylation in bladder cancer. Methylation-specific polymerase chain reaction was used to examine the promoter methylation status of PCDH17 in tumour tissue specimens obtained from patients with bladder cancer, and in normal bladder epithelial tissue specimens obtained from age- and sex-matched controls. The correlations between methylation status and demographic and clinicopathological parameters, and disease outcome, were assessed. Methylation of the PCDH17 promoter was detected in 77/115 (67.0%) patients with bladder cancer and 0/43 (0%) of the controls. Methylation was significantly associated with high cancer grade (G3), advanced cancer stage (T2-T4), large tumour diameter (> 3 cm) and tumour recurrence. Methylation was also associated with significantly shorter survival time compared with unmethylated PCDH17 in patients with bladder cancer, and was an independent predictor of overall survival. PCDH17 promoter methylation is closely associated with bladder cancer malignancy and may be used as an independent predictor of clinical outcomes in patients with bladder cancer.

Protocadherin-17 promoter methylation in serum-derived DNA is associated with poor prognosis of bladder cancer

To investigate the prognostic value of protocadherin 17 (PCDH17) promoter methylation in serum-derived DNA of patients with bladder cancer. DNA was isolated from serum of patients with bladder cancer and from age- and sex-matched controls. Methylation-specific polymerase chain reaction was used to examine the methylation status of the PCDH17 promoter. The correlations between methylation status and clinicopathological characteristics and overall survival were examined. PCDH17 promoter methylation was detected in 79/151 (52.3%) of patients with bladder cancer, and none of the 43 control subjects. Methylation was significantly associated with larger tumour diameter (>3 cm), high grade (G3) and advanced stage (T2-T4). Patients with PCDH17 promoter methylation had significantly shorter overall survival than those with unmethylated PCDH17 promoter. Methylation was an independent predictor of overall survival. PCDH17 promoter methylation was significantly associated with malignant behaviour and poor prognosis of bladder cancer. The detection of PCDH17 promoter methylation in serum-derived DNA may be a convenient and noninvasive predictive biomarker in routine clinical practice.

Epigenetic alteration: new insights moving from tissue to plasma – the example of PCDH10 promoter methylation in colorectal cancer

Background:Tumour-released DNA in blood represents a promising biomarker for cancer detection. Although epigenetic alterations such as aberrant promoter methylation represent an appealing perspective, the discordance existing between frequencies of alterations found in DNA extracted from tumour tissue and cell-free DNA (cfDNA) has challenged their practical clinical application. With the aim to explain this bias of agreement, we investigated whether protocadherin 10 (PCDH10) promoter methylation in tissue was associated with methylation pattern in matched cfDNA isolated from plasma of patients with colorectal cancer (CRC), and whether the strength of concordance may depend on levels of cfDNA, integrity index, as well as on different clinical–pathological features.Methods:A quantitative methylation-specific PCR was used to analyse a selected CpG site in the PCDH10 promoter of 67 tumour tissues, paired normal mucosae, and matched plasma samples. The cfDNA integrity index and cfDNA concentration were assessed using a real-time PCR assay.Results:The PCDH10 promoter methylation was detected in 63 out of 67 (94.0%) surgically resected colorectal tumours and in 42 out of 67 (62.7%) plasma samples. The median methylation rate in tumour tissues and plasma samples was 43.5% (6.3–97.8%) and 5.9% (0–80.9%), respectively. There was a significant correlation between PCDH10 methylation in cfDNA and tumour tissue in patients with early CRC (P<0.0001). The ratio between plasma and tissue methylation rate increases with increasing cfDNA integrity index in early-stage cancers (P=0.0299) and with absolute cfDNA concentration in advanced cancers (P=0.0234).Conclusion:Our findings provide new insight into biological aspects modulating the concordance between tissues and plasma methylation profiles.

Protocadherin 10 is frequently downregulated by promoter methylation and functions as a tumor suppressor gene in non-small cell lung cancer

Protocadherin 10 (PCDH10), a homophilic cell adhesion member of the protocadherin family, plays important roles in calcium-dependent cell-cell adhesion and signal transduction. PCDH10 expression is downregulated in a number of different malignances, predominantly through promoter methylation-driven silencing. This study was designed to investigate PCDH10 expression and promoter methylation status in non-small cell lung cancer (NSCLC), and biological effects of PCDH10 in lung cancer cells. The mRNA levels and promoter methylation status of PCDH10 were examined by RT-PCR and methylation-specific PCR (MSP) in lung cancer cell lines as well as primary lung tissue samples, and the clinical correlation of PCDH10 promoter methylation in NSCLC was further analyzed. The effects of PCDH10 re-expression in lung cancer cell lines was determined by cell proliferation, colony formation, and wound healing assays. PCDH10 expression was downregulated or silenced in 4/8 lung cancer cell lines but could be restored by treatment with 5-aza-2'-deoxycytidine and trichostatin A. PCDH10 was also downregulated in NSCLC tissues compared to their corresponding adjacent tissues. Promoter methylation of PCDH10 was observed in 50% (20/40) of the NSCLC tissues but not in tumor-adjacent or normal tissues, and PCDH10 promoter methylation was statistically related to smoking. Ectopic expression of PCDH10 in silenced cells can reduce lung cancer cell proliferation and migration. PCDH10 is frequently downregulated by promoter methylation and may serve as a tumor suppressor gene (TSG) in NSCLC.

Clinical and Prognostic Significance of Protocadherin-10 (PCDH10) Promoter Methylation in Bladder Cancer

To investigate the clinical and prognostic significance of protocadherin-10 (PCDH10) promoter methylation in serum-derived DNA from patients with bladder cancer. PCDH10 promoter methylation status was determined using methylation-specific polymerase chain reaction of DNA extracted from serum of patients with bladder cancer, and age- and sex-matched controls. Clinical and pathological details of bladder cancer were recorded. PCDH10 promoter methylation was detected in 59/117 (50.4%) of patients with bladder cancer, and none of 37 (0%) controls. Methylation was significantly associated with advanced stage (T(2)-T(4)), high grade (G(3)), tumour recurrence and larger tumour size (> 3 cm). In addition, methylation was associated with significantly worse survival and was an independent predictor of overall survival. Serum-based analysis of PCDH10 promoter methylation may represent a useful noninvasive biomarker of malignant behaviour and outcome in bladder cancer.

The Clinical Significance of PCDH10 Promoter Methylation in Patients with Bladder Transitional Cell Carcinoma

Objective: To investigate the clinical significance of PCDH10 (protocadherin 10) promoter methylation in patients with bladder transitional cell carcinoma (TCC). Materials and Methods: 107 samples of bladder TCC and 38 normal bladder epithelial tissues were investigated using methylation-specific PCR, and the relationships between PCDH10 methylation and clinicopathologic features as well as patients' outcome were analyzed. Results: PCDH10 methylation was detected in 63 (58.9%) bladder TCC samples, but no methylation of PCDH10 was found in controls. Moreover, PCDH10 methylation was significantly associated with larger tumor size (p = 0.0074), non-papillary shape (p = 0.0268), tumor relapse (p = 0.0029), high grade (p = 0.0397), advanced stage (p = 0.0004) and poor prognosis (p = 0.0009). In addition, multivariate analysis indicated that PCDH10 methylation is independently associated with poor outcome and may be used as a useful independent prognostic factor (p = 0.0255). Conclusions: PCDH10 methylation is closely associated with malignancy of bladder TCC and may be used as an independent predictor for patients with bladder TCC.

PCDH17 gene promoter demethylation and cell cycle arrest by genistein in gastric cancer.

Protocadherin 17 (PCDH17) is a member of the cadherin superfamily, but little is known about its functions. We focused on it as a candidate tumor suppressor gene (TSG) and hypothesized that PCDH17 may be susceptible to promoter methylation and gene silencing. Genistein has been reported to upregulate mRNA expression in many TSGs. We further tried to determine whether genistein could increase transcriptional PCDH17 by promoter demethylation. Gastric cancer cell line AGS and normal gastric cell line Ges-1 were treated with genistein and 5-aza-2'-deoxycytidine (5Aza-C). Fluorescence-activated cell sorting was performed to analyze cell cycle and apoptosis, and cell proliferation was examined by cell viability assay. PCDH17 mRNA expression in pairs of gastric cancer and normal tissue samples and cell lines were determined by quantitative real-time polymerase chain reaction. Bisulfite-modified polymerase chain reaction, cloning and sequencing were used to examine promoter methylation. We found genistein has an anti-proliferative effect on cancer cell growth through induction of cell cycle arrest. PCDH17 mRNA expression was down-regulated in cancer tissues, and PCDH17 promoter in cancer tissues was hyper-methylated in comparison with normal ones. Genistein and 5Aza-C induced PCDH17 mRNA expression in AGS, but not in Ges-1. Furthermore, genistein and 5Aza-C treatment significantly decreased promoter methylation in putative methylation target regions in AGS, reactivating PCDH17 expression. These results suggest that silencing of PCDH17 expression through promoter hypermethylation leads to loss of its tumor-suppressive activity. Genistein showed similar effects to that of 5Aza-C. Our results indicate that genistein is a novel, advantageous therapeutic agent for treating gastric cancer.

Epigenetic inactivation of PCDH10 in human prostate cancer cell lines

PCDH10 (protocadherin-10), a novel tumour suppressor gene, is down-regulated in several human cancers due to hypermethylation of promoter CGIs (CpG islands). Here, we investigated the expression of PCDH10 in different normal adult tissues and in a panel of prostate cancer cell lines. PCDH10 was widely expressed in normal tissues with higher levels in the prostate. The expression of PCDH10 was markedly reduced or silenced in prostate cancer cell lines compared with normal adult prostate tissue. Decreased PCDH10 expression was correlated with the methylation status of the PCDH10 promoter. Furthermore, the DNA demethylating agent 5'-azacytidin restored PCDH10 expression by suppressing PCDH10 promoter methylation in prostate cancer cell lines. Treatment with Trichostatin A alone had no significant effect on the expression of PCDH10 but enhanced the effect of 5'-azacytidin. In conclusion, we found that the decreased PCDH10 expression in prostate cancer cells was associated with the aberrant methylation of PCDH10 promoter CGI. Our results may contribute to the understanding of the role of PCDH10 inactivation in the progression of prostate cancers.

Abstract 3071: Frequent silencing of protocadherin 17, a candidate tumour suppressor for esophageal squamous-cell carcinoma

Abstract Protocadherins are a subfamily of the cadherin superfamily, but little is known about their functions. We identified a homozygous loss of protocadherin 17 (PCDH17) in the course of a program to screen a panel of esophageal squamous-cell carcinoma (ESCC) cell lines for genomic copy-number aberrations. PCDH17 mRNA was expressed in normal esophageal tissue but not in the majority of ESCC cell lines without a homozygous deletion of this gene, and restored in gene-silenced ESCC cells after treatment with 5-aza-2′-deoxycytidine. The DNA methylation status of the PCDH17 CpG-island correlated inversely with the PCDH17 expression, and a putative methylation-target region showed promoter activity. The methylation of the PCDH17 promoter was also associated with the silencing of gene expression in primary ESCC at least partly. Among primary ESCC cases, the silencing of PCDH17 protein expression was associated with a poorer differentiation status of ESCC cells, and possibly with prognosis in a subset of this tumour. Restoration of PCDH17 expression in ESCC cells reduced cell proliferation and migration/invasion. These results suggest that silencing of PCDH17 expression through hypermethylation of the promoter or other mechanisms leads to loss of its tumour-suppressive activity, which may be a factor in the carcinogenesis of at least some ESCCs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3071.