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MP55-08 GENOMIC DELETION OF CHROMOSOME 12P IS AN INDEPENDENT PROGNOSTIC MARKER IN PROSTATE CANCER
THE JOURNAL OF UROLOGYâ
Vol. 193, No. 4S, Supplement, Sunday, May 17, 2015
MP55-06 GALECTIN-3 IS A THERAPEUTIC TARGET FOR CASTRATIONRESISTANT PROSTATE CANCER Tomoharu Fukumori*, Tsogt-Ochir Dondoo, Kei Daizumoto, Tomoya Fukawa, Yasuyo Yamamoto, Kunihisa Yamaguchi, Masayuki Takahashi, Tokushima, Japan; Hiro-omi Kanayama, Tokushima, Japan INTRODUCTION AND OBJECTIVES: Castration-resistant prostate cancer (CRPC) has been common and CRPC-related death has been increasing. Therefore, to clarify the mechanism of tumor progression and resistance to anti-androgen drug is useful for the strategy of appropriate treatment for CRPC. Galectin-3 has been shown to be correlated with tumor progression and metastasis in a variety of cancer cells through the regulation of tumor proliferation, angiogenesis, and apoptosis. Here, we investigate the effects of galectin-3 on the tumor progression and resistance to anti-androgen drug in CRPC. METHODS: Endogenous galectin-3 expression was examined by immunohistochemical analysis in human CRPC specimen, and serum galectin-3 was measured by ELISA. We generated continuous galectin-3-overexpressed LNCaP cells and galectin-3-downregulated PC-3 cells using siRNA. The invasion and migration assays in LNCaP and PC-3 cells with or without galectin-3 were performed by the xCELLigence system. Androgen receptor (AR)-dependent gene PSA expression was measured by RT-PCR in LNCaP cells with or without galectin-3 cultured in androgen-depleted media and treated for 24 hours with or without DHT (1 nM) combined with mock, enzalutamide (10 mM), and bicalutamide (10 mM). Transcriptional activity of AR were measured by luciferase reporter assay for the PSA promoter. RESULTS: The CRPC highly expressed galectin-3 in both cytoplasm and nuclei, and mean concentration of human serum galectin-3 adjusted by prostate volume in CRPC was higher than that of non-malignancy control (6178 vs. 1671 pg/ml, p<0.001) and hormonenaive prostate cancer (6178 vs. 3021 pg/ml, p¼0.008). Overexpression of galectin-3 in LNCaP cells promoted invasion (cell index; 0.39 vs. 0.07) and migration of tumor cells (cell index; 0.30 vs. 0.02) comparing with control LNCaP cells. Downregulation of galectin-3 in PC-3 cells suppressed invasion (cell index; 1.64 vs. 0.89) and migration (cell index; 0.84 vs. 0.42) comparing with control PC-3 cells. Galectin-3 significantly suppressed anti-androgen effect induced by enzalutamide (PSA expression ratio; 0.47 vs. 0.15, p¼0.005) or bicalutamide (PSA expression ratio; 0.49 vs. 0.26, p¼0.001) in LNCaP comparing with controls by activating androgen transcriptional activity of AR. CONCLUSIONS: These data indicate that galectin-3 is involved in the tumor progression and anti-androgen drug resistance of CRPC by regulating invasion, migration, and transcriptional activity of AR. These results suggest that galectin-3 is one of the target molecules for future treatments in CRPC. Source of Funding: none
MP55-07 FLAVONOIDS ENHANCE TRAIL SENSITIVITY IN PROSTATE CANCER CELLS BY TARGETING ADENINE NUCLEOTIDE TRANSLOCASE-2 Masakatsu Oishi*, Takashi Ueda, Terukazu Nakamura, Yoshio Naya, Fumiya Hongo, Kazumi Kamoi, Koji Okihara, Tsuneharu Miki, Kyoto, Japan INTRODUCTION AND OBJECTIVES: Tumor necrosis factorrelated apoptosis-inducing ligand (TRAIL) is a promising cancer therapeutic agent. Recombinant human TRAIL has been under clinical trials, whereas various kinds of malignant tumors have resistance to TRAIL. It has been shown that several anticancer agents and flavonoids (apigenin, quercetin etc.) overcome resistance to TRAIL by upregulating death receptor 5 (DR5) in malignant tumor cells. However, the mechanisms by which these compounds induce DR5 expression remain unknown. On the other hand, although docetaxel plus prednisone is
e675
effective in hormone-refractory prostate cancer, the outcome of this treatment is still insufficient. Therefore, new strategies are needed to treat this cancer. Thus we investigated the mechanism in a hormonerefractory prostate cancer cell line DU145. METHODS: To elucidate the mechanisms by which flavonoids induce DR5 expression in DU145 cells, we explored the proteins binding to flavonoids using FG beads with epoxy linkers. We fixed genistein, which enhances TRAIL sensitivity without upregulating DR5, apigenin, and quercetin onto these beads (Figure 1A). The binding proteins of apigenin, quercetin, and genistein were purified from the DU145 whole cell extracts and were identified by MALDI-TOF MS analysis. Then, function of binding proteins was analized. RESULTS: Comparing the binding proteins, we discovered that ANT2 was a target of apigenin and quercetin, but not genistein in DU145 cells (Figure 1B). Similarly to treatment of apigenin and quercetin, knockdown of ANT2 enhanced TRAIL-induced apoptosis by upregulating DR5 expression. Moreover, silencing of ANT2 attenuated the enhancement of TRAIL-induced apoptosis by apigenin or quercetin. CONCLUSIONS: These results suggest that flavonoids upregulate DR5 and enhance TRAIL-induced apoptosis in hormonerefractory prostate cancer cells by binding and inhibiting ANT2 (Figure 1C). We propose that ANT2 inhibitors may contribute to TRAIL therapy in hormone-refractory prostate cancer.
Source of Funding: none
MP55-08 GENOMIC DELETION OF CHROMOSOME 12P IS AN INDEPENDENT PROGNOSTIC MARKER IN PROSTATE CANCER Raisa Pompe*, Martina Kluth, Sarah Minner, Philipp Gild, Ronald Simon, Pierre Tennstedt, Markus Graefen, Guido Sauter, Thorsten Schlomm, Hamburg, Germany INTRODUCTION AND OBJECTIVES: Deletion of 12p is a recurrent alteration in prostate cancer, but the prevalence and clinical consequences of this alteration have not been studied in detail. METHODS: Dual labeling fluorescence in situ hybridization (FISH) using probes for 12p13 (CDKN1B; p27) and for centromere 12 as a reference was used to analyze more than 7,000 prostate cancers with clinical follow-up data assembled in a tissue microarray (TMA) format. CDKN1B was selected as a probe because it is located in the center of the deletion, which, however, spans >10 Mb and includes >50 genes in 80% of cancers with 12p deletion. Results were compared to clinically follow-up data, ERG status and p27 protein expression in univariate und multivariate analyses. RESULTS: Deletion of 12p was found in 13.7% of cancers and included 13.5% hemizygeous and 0.2% homozygeous deletions. 12p deletion were linked to advanced tumor stage (p<0.0001), high Gleason grade (p<0.0001), lymph node metastasis (p¼0.0004), rapid tumor
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cell proliferation (p<0.0001), and early biochemical recurrence (BCR) (p¼0.0027). Multivariate cox regression analysis including pT stage (p<0.0001), Gleason grade (p<0.0001), pN status (p¼0.0001), preoperative PSA levels (p¼0.0001), and resection margin status (p¼0.0001) revealed an independent prognostic value of 12p deletion (p¼0.0014). Deletion of 12p was unrelated to the ERG fusion status. Deletion of 12p was only marginally linked to reduced p27 expression, which by itself was unrelated to clinical outcome. This argues against p27 as the key target gene of 12p deletions. As none of the involved 12p genes is recurrently mutated in next generation sequencing studies, simultaneous dosage reduction of multiple genes may exert a relevant biological effect in 12p deleted cancers. CONCLUSIONS: The results of our study demonstrate that 12p deletion is frequent in prostate cancer and provides independent prognostic information. 12p deletion analysis alone, or in combination with other prognostic parameters may thus have clinical utility. Source of Funding: none Source of Funding: none
MP55-09 PRE-CLINICAL EVALUATION OF THE NOVEL THERAPIES OF THE CASTRATION-RESISTANT PROSTATE CANCER David Charbit, Ihsan El Sayed, Alexandra Masson-Lecomte, Carolina Saldana, Laurent Salomon, Francis Vacherot, Alexandre De La Taille*, Creteil, France INTRODUCTION AND OBJECTIVES: The arrival of the novel hormonotherapies, Abiraterone Acetate (AA) and Enzalutamide (ENZ) and a new taxane, the Cabazitaxel (CBZ) has significantly modified the therapeutic approach of castration-resistant prostate cancer patients. However, no logical sequence has been proposed yet. The purpose of this study is to assess the toxicity of these novel treatments which intent to reproduce the prostatic tumoral cell lines pattern during the different stages of cancer development. METHODS: Hormono-sensitive (LNCaP), hormono-resistant (PC3, 22RV1), and Chemo-hormono resistant (LNCaP-NE, neuroendocrine profile) cell lines were exposed to AA and ENZ at different doses. Three testing groups have been defined: monotherapy (3 days), combination (3 days) and sequence (6 days). CBZ and Docetaxel (DTX) were tested only by monotherapy. The MTT test was used to evaluate cellular viability and calculate median inhibitive concentration (IC50). RESULTS: In monotherapy, regardless to the preclinical model utilized, higher IC50 was found for AA and DTX when respectively compared to ENZ and CBZ. The overall IC50 mean (including every cell types) was 35,7nM for DTX vs 4,02nM for CBZ and 62,9mM for AA vs 35,2mM pour l’ENZ. When combined, AA and ENZ showed reduction of the IC50 in comparison with monotherapy (AA or ENZ). Significantly high differences were measured for the samples containing LNCaP and PC3 cell lines. If this phenomenon was still observed for cell lines 22RV1 and LNCaP-NE, it was observed in a less important extent (Graph 1). Regarding cellular viability, there was no difference between the two following sequences order: AA followed by ENZ versus ENZ followed by AA. According to cell viability curves, these results were similar for all the tested samples. CONCLUSIONS: Under in vitro conditions, the monotherapy treatment with ENZ seems to be more efficient than AA therapy, similarly to CBZ when compared with DTX. In addition, the sequences of treatment appeared not to be related with the aggressiveness of the tumoral cell line. However, on the basis of these results, it can be assumed that a synergic effect of two concomitant drugs could lead to better outcome during the early stages of prostate carcinoma therapy. In vivo studies are needed to draw any consistent conclusions and to confirm these preliminary results.
MP55-10 EPIGENETIC REGULATION OF THE 3P22 TUMOR SUPPRESSOR DLEC1 IN HUMAN PROSTATE CANCER ASSOCIATED WITH ITS PROGNOSIS Lian Zhang, Yu Fan*, Beijing, China, People’s Republic of; Lili Li, Zhaohui Wang, Hong Kong, China, People’s Republic of; Qian Zhang, Beijing, China, People’s Republic of; Qian Tao, Hong Kong, China, People’s Republic of; Jie Jin, Beijing, China, People’s Republic of INTRODUCTION AND OBJECTIVES: Deleted in lung and esophageal cancer 1 (DLEC1), located on 3p22-p21.3, is involved in carcinogenesis of multiple cancers, but its role in prostate cancer (PrCa) remains unclear. Here, we reported the epigenetic alterations of DLEC1 and its biological function in prostate carcinogenesis, and also studied the potentially useful application of DLEC1 methylation in prostate cancer diagnosis. METHODS: We detected the expression and methylation of DLEC1, and assessed its tumor suppressive functions in PrCa cell lines (PC3, DU145, and LNCap). DLEC1 methylation was further examined by methylation-specific PCR in tissue DNA from 110 prostate carcinomas and 26 benign prostatic hyperplasias (BPH). We also detected the methylation of DLEC1 promoter in the urine sediments from the pre-biopsy patients with elevated PSA. All samples were harvested after obtaining patients’ written content and defined by two urological pathology physicians. RESULTS: It’s observed that DLEC1 was highly expressed in human normal prostatic epithelium cell line (RWPE-1), benign prostatic hyperplasia cell line (BPH-1) and normal prostate tissue, but frequently downregulated by promoter methylation in PrCa cell lines. PrCa tissues expressed lower level of DLEC1 than their adjacent non-malignant tissues. DLEC1 was methylated in 76 out of 110 primary tumors, but rarely in BPH tissues. This methylation was associated with higher PSA levels (p¼0.016), higher gleason scores (p¼0.015), and more advanced tumor stages (p¼0.003). Furthermore, DLEC1 methyation was detected in 35 out of 95 urine sediments from confirmed PrCa patients, 20 out of 81 urine sediments from the unconfirmed PrCa patient with elevated PSA. Pharmacologic demethylation treatment restored DLEC1 expression. Re-expression of DLEC1 inhibited colony formation and migration abilities of PrCa cells, through promoting apoptosis. Moreover, overexpression of DLEC1 could inhibit the activities of NF-kB both in PrCa cells and HEK293 cells. CONCLUSIONS: Taken together, our data suggests that DLEC1 as a functional tumor suppressor may be frequently methylated in PrCa and associates with tumor progression. The DLEC1 methylation detection in urine sediments indicates that it might serve as a potential noninvasive neo-biomarker for prostate cancer early diagnosis. Source of Funding: National Natural Science Foundation (No. 81272290); Beijing Municipal Science & Technology Commission (No.Z131107002213130); Central Health Care Research Foundation (No. W2013BJ28).
Vol. 193, No. 4S, Supplement, Sunday, May 17, 2015
MP55-06 GALECTIN-3 IS A THERAPEUTIC TARGET FOR CASTRATIONRESISTANT PROSTATE CANCER Tomoharu Fukumori*, Tsogt-Ochir Dondoo, Kei Daizumoto, Tomoya Fukawa, Yasuyo Yamamoto, Kunihisa Yamaguchi, Masayuki Takahashi, Tokushima, Japan; Hiro-omi Kanayama, Tokushima, Japan INTRODUCTION AND OBJECTIVES: Castration-resistant prostate cancer (CRPC) has been common and CRPC-related death has been increasing. Therefore, to clarify the mechanism of tumor progression and resistance to anti-androgen drug is useful for the strategy of appropriate treatment for CRPC. Galectin-3 has been shown to be correlated with tumor progression and metastasis in a variety of cancer cells through the regulation of tumor proliferation, angiogenesis, and apoptosis. Here, we investigate the effects of galectin-3 on the tumor progression and resistance to anti-androgen drug in CRPC. METHODS: Endogenous galectin-3 expression was examined by immunohistochemical analysis in human CRPC specimen, and serum galectin-3 was measured by ELISA. We generated continuous galectin-3-overexpressed LNCaP cells and galectin-3-downregulated PC-3 cells using siRNA. The invasion and migration assays in LNCaP and PC-3 cells with or without galectin-3 were performed by the xCELLigence system. Androgen receptor (AR)-dependent gene PSA expression was measured by RT-PCR in LNCaP cells with or without galectin-3 cultured in androgen-depleted media and treated for 24 hours with or without DHT (1 nM) combined with mock, enzalutamide (10 mM), and bicalutamide (10 mM). Transcriptional activity of AR were measured by luciferase reporter assay for the PSA promoter. RESULTS: The CRPC highly expressed galectin-3 in both cytoplasm and nuclei, and mean concentration of human serum galectin-3 adjusted by prostate volume in CRPC was higher than that of non-malignancy control (6178 vs. 1671 pg/ml, p<0.001) and hormonenaive prostate cancer (6178 vs. 3021 pg/ml, p¼0.008). Overexpression of galectin-3 in LNCaP cells promoted invasion (cell index; 0.39 vs. 0.07) and migration of tumor cells (cell index; 0.30 vs. 0.02) comparing with control LNCaP cells. Downregulation of galectin-3 in PC-3 cells suppressed invasion (cell index; 1.64 vs. 0.89) and migration (cell index; 0.84 vs. 0.42) comparing with control PC-3 cells. Galectin-3 significantly suppressed anti-androgen effect induced by enzalutamide (PSA expression ratio; 0.47 vs. 0.15, p¼0.005) or bicalutamide (PSA expression ratio; 0.49 vs. 0.26, p¼0.001) in LNCaP comparing with controls by activating androgen transcriptional activity of AR. CONCLUSIONS: These data indicate that galectin-3 is involved in the tumor progression and anti-androgen drug resistance of CRPC by regulating invasion, migration, and transcriptional activity of AR. These results suggest that galectin-3 is one of the target molecules for future treatments in CRPC. Source of Funding: none
MP55-07 FLAVONOIDS ENHANCE TRAIL SENSITIVITY IN PROSTATE CANCER CELLS BY TARGETING ADENINE NUCLEOTIDE TRANSLOCASE-2 Masakatsu Oishi*, Takashi Ueda, Terukazu Nakamura, Yoshio Naya, Fumiya Hongo, Kazumi Kamoi, Koji Okihara, Tsuneharu Miki, Kyoto, Japan INTRODUCTION AND OBJECTIVES: Tumor necrosis factorrelated apoptosis-inducing ligand (TRAIL) is a promising cancer therapeutic agent. Recombinant human TRAIL has been under clinical trials, whereas various kinds of malignant tumors have resistance to TRAIL. It has been shown that several anticancer agents and flavonoids (apigenin, quercetin etc.) overcome resistance to TRAIL by upregulating death receptor 5 (DR5) in malignant tumor cells. However, the mechanisms by which these compounds induce DR5 expression remain unknown. On the other hand, although docetaxel plus prednisone is
e675
effective in hormone-refractory prostate cancer, the outcome of this treatment is still insufficient. Therefore, new strategies are needed to treat this cancer. Thus we investigated the mechanism in a hormonerefractory prostate cancer cell line DU145. METHODS: To elucidate the mechanisms by which flavonoids induce DR5 expression in DU145 cells, we explored the proteins binding to flavonoids using FG beads with epoxy linkers. We fixed genistein, which enhances TRAIL sensitivity without upregulating DR5, apigenin, and quercetin onto these beads (Figure 1A). The binding proteins of apigenin, quercetin, and genistein were purified from the DU145 whole cell extracts and were identified by MALDI-TOF MS analysis. Then, function of binding proteins was analized. RESULTS: Comparing the binding proteins, we discovered that ANT2 was a target of apigenin and quercetin, but not genistein in DU145 cells (Figure 1B). Similarly to treatment of apigenin and quercetin, knockdown of ANT2 enhanced TRAIL-induced apoptosis by upregulating DR5 expression. Moreover, silencing of ANT2 attenuated the enhancement of TRAIL-induced apoptosis by apigenin or quercetin. CONCLUSIONS: These results suggest that flavonoids upregulate DR5 and enhance TRAIL-induced apoptosis in hormonerefractory prostate cancer cells by binding and inhibiting ANT2 (Figure 1C). We propose that ANT2 inhibitors may contribute to TRAIL therapy in hormone-refractory prostate cancer.
Source of Funding: none
MP55-08 GENOMIC DELETION OF CHROMOSOME 12P IS AN INDEPENDENT PROGNOSTIC MARKER IN PROSTATE CANCER Raisa Pompe*, Martina Kluth, Sarah Minner, Philipp Gild, Ronald Simon, Pierre Tennstedt, Markus Graefen, Guido Sauter, Thorsten Schlomm, Hamburg, Germany INTRODUCTION AND OBJECTIVES: Deletion of 12p is a recurrent alteration in prostate cancer, but the prevalence and clinical consequences of this alteration have not been studied in detail. METHODS: Dual labeling fluorescence in situ hybridization (FISH) using probes for 12p13 (CDKN1B; p27) and for centromere 12 as a reference was used to analyze more than 7,000 prostate cancers with clinical follow-up data assembled in a tissue microarray (TMA) format. CDKN1B was selected as a probe because it is located in the center of the deletion, which, however, spans >10 Mb and includes >50 genes in 80% of cancers with 12p deletion. Results were compared to clinically follow-up data, ERG status and p27 protein expression in univariate und multivariate analyses. RESULTS: Deletion of 12p was found in 13.7% of cancers and included 13.5% hemizygeous and 0.2% homozygeous deletions. 12p deletion were linked to advanced tumor stage (p<0.0001), high Gleason grade (p<0.0001), lymph node metastasis (p¼0.0004), rapid tumor
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cell proliferation (p<0.0001), and early biochemical recurrence (BCR) (p¼0.0027). Multivariate cox regression analysis including pT stage (p<0.0001), Gleason grade (p<0.0001), pN status (p¼0.0001), preoperative PSA levels (p¼0.0001), and resection margin status (p¼0.0001) revealed an independent prognostic value of 12p deletion (p¼0.0014). Deletion of 12p was unrelated to the ERG fusion status. Deletion of 12p was only marginally linked to reduced p27 expression, which by itself was unrelated to clinical outcome. This argues against p27 as the key target gene of 12p deletions. As none of the involved 12p genes is recurrently mutated in next generation sequencing studies, simultaneous dosage reduction of multiple genes may exert a relevant biological effect in 12p deleted cancers. CONCLUSIONS: The results of our study demonstrate that 12p deletion is frequent in prostate cancer and provides independent prognostic information. 12p deletion analysis alone, or in combination with other prognostic parameters may thus have clinical utility. Source of Funding: none Source of Funding: none
MP55-09 PRE-CLINICAL EVALUATION OF THE NOVEL THERAPIES OF THE CASTRATION-RESISTANT PROSTATE CANCER David Charbit, Ihsan El Sayed, Alexandra Masson-Lecomte, Carolina Saldana, Laurent Salomon, Francis Vacherot, Alexandre De La Taille*, Creteil, France INTRODUCTION AND OBJECTIVES: The arrival of the novel hormonotherapies, Abiraterone Acetate (AA) and Enzalutamide (ENZ) and a new taxane, the Cabazitaxel (CBZ) has significantly modified the therapeutic approach of castration-resistant prostate cancer patients. However, no logical sequence has been proposed yet. The purpose of this study is to assess the toxicity of these novel treatments which intent to reproduce the prostatic tumoral cell lines pattern during the different stages of cancer development. METHODS: Hormono-sensitive (LNCaP), hormono-resistant (PC3, 22RV1), and Chemo-hormono resistant (LNCaP-NE, neuroendocrine profile) cell lines were exposed to AA and ENZ at different doses. Three testing groups have been defined: monotherapy (3 days), combination (3 days) and sequence (6 days). CBZ and Docetaxel (DTX) were tested only by monotherapy. The MTT test was used to evaluate cellular viability and calculate median inhibitive concentration (IC50). RESULTS: In monotherapy, regardless to the preclinical model utilized, higher IC50 was found for AA and DTX when respectively compared to ENZ and CBZ. The overall IC50 mean (including every cell types) was 35,7nM for DTX vs 4,02nM for CBZ and 62,9mM for AA vs 35,2mM pour l’ENZ. When combined, AA and ENZ showed reduction of the IC50 in comparison with monotherapy (AA or ENZ). Significantly high differences were measured for the samples containing LNCaP and PC3 cell lines. If this phenomenon was still observed for cell lines 22RV1 and LNCaP-NE, it was observed in a less important extent (Graph 1). Regarding cellular viability, there was no difference between the two following sequences order: AA followed by ENZ versus ENZ followed by AA. According to cell viability curves, these results were similar for all the tested samples. CONCLUSIONS: Under in vitro conditions, the monotherapy treatment with ENZ seems to be more efficient than AA therapy, similarly to CBZ when compared with DTX. In addition, the sequences of treatment appeared not to be related with the aggressiveness of the tumoral cell line. However, on the basis of these results, it can be assumed that a synergic effect of two concomitant drugs could lead to better outcome during the early stages of prostate carcinoma therapy. In vivo studies are needed to draw any consistent conclusions and to confirm these preliminary results.
MP55-10 EPIGENETIC REGULATION OF THE 3P22 TUMOR SUPPRESSOR DLEC1 IN HUMAN PROSTATE CANCER ASSOCIATED WITH ITS PROGNOSIS Lian Zhang, Yu Fan*, Beijing, China, People’s Republic of; Lili Li, Zhaohui Wang, Hong Kong, China, People’s Republic of; Qian Zhang, Beijing, China, People’s Republic of; Qian Tao, Hong Kong, China, People’s Republic of; Jie Jin, Beijing, China, People’s Republic of INTRODUCTION AND OBJECTIVES: Deleted in lung and esophageal cancer 1 (DLEC1), located on 3p22-p21.3, is involved in carcinogenesis of multiple cancers, but its role in prostate cancer (PrCa) remains unclear. Here, we reported the epigenetic alterations of DLEC1 and its biological function in prostate carcinogenesis, and also studied the potentially useful application of DLEC1 methylation in prostate cancer diagnosis. METHODS: We detected the expression and methylation of DLEC1, and assessed its tumor suppressive functions in PrCa cell lines (PC3, DU145, and LNCap). DLEC1 methylation was further examined by methylation-specific PCR in tissue DNA from 110 prostate carcinomas and 26 benign prostatic hyperplasias (BPH). We also detected the methylation of DLEC1 promoter in the urine sediments from the pre-biopsy patients with elevated PSA. All samples were harvested after obtaining patients’ written content and defined by two urological pathology physicians. RESULTS: It’s observed that DLEC1 was highly expressed in human normal prostatic epithelium cell line (RWPE-1), benign prostatic hyperplasia cell line (BPH-1) and normal prostate tissue, but frequently downregulated by promoter methylation in PrCa cell lines. PrCa tissues expressed lower level of DLEC1 than their adjacent non-malignant tissues. DLEC1 was methylated in 76 out of 110 primary tumors, but rarely in BPH tissues. This methylation was associated with higher PSA levels (p¼0.016), higher gleason scores (p¼0.015), and more advanced tumor stages (p¼0.003). Furthermore, DLEC1 methyation was detected in 35 out of 95 urine sediments from confirmed PrCa patients, 20 out of 81 urine sediments from the unconfirmed PrCa patient with elevated PSA. Pharmacologic demethylation treatment restored DLEC1 expression. Re-expression of DLEC1 inhibited colony formation and migration abilities of PrCa cells, through promoting apoptosis. Moreover, overexpression of DLEC1 could inhibit the activities of NF-kB both in PrCa cells and HEK293 cells. CONCLUSIONS: Taken together, our data suggests that DLEC1 as a functional tumor suppressor may be frequently methylated in PrCa and associates with tumor progression. The DLEC1 methylation detection in urine sediments indicates that it might serve as a potential noninvasive neo-biomarker for prostate cancer early diagnosis. Source of Funding: National Natural Science Foundation (No. 81272290); Beijing Municipal Science & Technology Commission (No.Z131107002213130); Central Health Care Research Foundation (No. W2013BJ28).