Prostate cancer antigen-1 as a cancer potential novel marker for prostate

Aim： To examine the expression of prostate cancer antigen-1 （PCA-1） in prostate cancer （PCa） and to validate it as a potential marker for diagnosis of PCa. Methods： In situ hybridization analysis of PCA-1 mRNA expression was performed on 40 benign prostate hyperplasia （BPH）, 16 high-grade prostatic intraepithelial neoplasm （HG-PIN）, 74 PCa and 34 other malignant carcinoma specimens. The level of PCA- 1 expression was semiquanfitatively scored by assessing both the percentage and intensity of PCA- 1 positive staining cells in the specimens. We then compared the PCA-1 expression between BPH, HG-PIN and PCa and evaluated the correlation of PCA-1 expression level with clinical parameters of PCa. Results： PCA-1 mRNA was expressed in the majority of both PCa and HG-PIN specimens but not in BPH and other malignant carcinoma. The expression level of PCA-1 increased along with a high Gleason score （P 〈 0.05）, and was unrelated to other clinical parameters of PCa （all P 〉 0.05）. Conclusion： The data suggest that PCA-1 might be a novel diagnostic marker for PCa, and that increased PCA-1 expression might denote more aggressive variants of PCa.

Aspartoacylase suppresses prostate cancer progression by blocking LYN activation

Background:Globally,despite prostate cancer(PCa)representing second most prevalent malignancy in male,the precise molecular mechanisms implicated in its pathogenesis remain unclear.Consequently,elucidating the key molecular regulators that govern disease progression could substantially contribute to the establishment of novel therapeutic strategies,ultimately advancing the management of PCa.Methods:A total of 49 PCa tissues and 43 adjacent normal tissues were collected from January 2017 to December 2021 at Zhongnan Hospital of Wuhan University.The advanced transcriptomic methodologies were employed to identify differentially expressed mRNAs in PCa.The expression of aspartoacylase(ASPA)in PCa was thoroughly evaluated using quantitative real-time PCR and Western blotting techniques.To elucidate the inhibitory role of ASPA in PCa cell proliferation and metastasis,a comprehensive set of in vitro and in vivo assays were conducted,including orthotopic and tumor-bearing mouse models(n=8 for each group).A combination of experimental approaches,such as Western blotting,luciferase assays,immunoprecipitation assays,mass spectrometry,glutathione S-transferase pulldown experiments,and rescue studies,were employed to investigate the underlying molecular mechanisms of ASPA's action in PCa.The Student‘s t-test was employed to assess the statistical significance between two distinct groups,while one-way analysis of variance was utilized for comparisons involving more than two groups.A two-sided P<0.05 was deemed to indicate statistical significance.Results:ASPA was identified as a novel inhibitor of PCa progression.The expression of ASPA was found to be significantly down-regulated in PCa tissue samples,and its decreased expression was independently associated with patients’prognosis(HR=0.60,95%CI 0.40–0.92,P=0.018).Our experiments demonstrated that modulation of ASPA activity,either through gain-or loss-of-function,led to the suppression or enhancement of PCa cell proliferation,migration,and invasion,respectively.The inhibitory role of ASPA in PCa was further confirmed using orthotopic and tumor-bearing mouse models.Mechanistically,ASPA was shown to directly interact with the LYN and inhibit the phosphorylation of LYN as well as its downstream targets,JNK1/2 and C-Jun,in both PCa cells and mouse models,in an enzyme-independent manner.Importantly,the inhibition of LYN activation by bafetinib abrogated the promoting effect of ASPA knockdown on PCa progression in both in vitro and in vivo models.Moreover,we observed an inverse relationship between ASPA expression and LYN activity in clinical PCa samples,suggesting a potential regulatory role of ASPA in modulating LYN signaling.Conclusions:Our findings provide novel insights into the tumor-suppressive function of ASPA in PCa and highlight its potential as a prognostic biomarker and therapeutic target for the management of this malignancy.

Deleted in liver cancer 1 suppresses the growth of prostate cancer cells through inhibiting Rho-associated protein kinase pathway

Objective:Deleted in liver cancer 1(DLC1)is a GTPase-activating protein that is reported as a suppressor in certain human cancers.However,the detailed biological function of DLC1 is still unclear in human prostate cancer(PCa).In the present study,we aimed to explore the function of DLC1 in PCa cells.Methods:Silencing and overexpression of DLC1 were induced in an androgen-sensitive PCa cell line(LNCaP)using RNA interference and lentiviral vector transduction.The Cell Counting Kit-8 assay was performed to determine cell proliferation.The cell cycle was examined by performing a propidium iodide staining assay.Results:Our results indicated that DLC1 overexpression markedly suppressed the proliferation and cell cycle progression of LNCaP cells.Moreover,DLC1 expression was negatively correlated with Rho-associated protein kinase(ROCK)expression in LNCaP cells.Importantly,this study showed that the ROCK inhibitor Y27632 restored the function of DLC1 in LNCaP cells and reduced the tumorigenicity of LNCaP cells in vivo.Conclusion:Our results indicated that DLC1 overexpression markedly suppressed the proliferation and cell cycle progression of PCa cells and negatively correlated with ROCK expression in PCa cells and tissue.

A novel cabazitaxel liposomes modified with ginsenoside Rk1 for cancer targeted therapy

Objective:In this study,we aim to enhance the anti-prostate cancer efficacy of cabazitaxel(CTX)and reduce its immunosuppression and systemic toxicity by developing CTX-loaded liposomes modified with ginsenoside Rk1(Rk1/CTX-Lip).Methods:Physical and chemical properties of Rk1/CTX-Lip were investigated.We evaluated the biological functions of Rk1/CTXLip,both in vitro and in vivo.A subcutaneous prostate cancer(RM-1)-bearing mouse model was established to study the efficacy of Rk1/CTX-Lip inhibition in tumors.Simultaneously,a Candida albicans infection model was established in tumor-bearing mice to study the infection-relieving efficacy of Rk1/CTX-Lip.Finally,biocompatibility and in vivo safety of Rk1/CTX-Lip were evaluated.Results:We successfully prepared Rk1/CTX-Lip,achieving high CTX encapsulation efficiency(97.24±0.75)%and physical stability.Rk1/CTX-Lip demonstrated evasion of macrophage phagocytosis,effective tumor tissue targeting,and a significant reduction(>50%)in average tumor volume compared with Chol/CTX-Lip.Moreover,it relieved the concurrent infection burden and effectively regulated immune organs and cells,demonstrating superior biocompatibility.Conclusion:Rk1/CTX-Lip presents a promising new therapy for prostate cancer and holds potential for relieving concurrent fungal infections in cancer patients with low immunity.

Downregulation of the nucleosome-binding protein 1 （NSBP1） gene can inhibit the in vitro and in vivo proliferation of prostate cancer cells

This studay is to construct a lentiviral vector harbouring an RNA interference （RNAi） sequence that targets the gene encoding the human high-mobility group nucleosomal binding protein 1 （NSBP1）; to study its role in inducing G2/M phase arrest and apoptosis in prostate cancer （PCa） DU145 cells; and to assess the effect of its knockdown on cell proliferation in vitro and in vivo. RNAi was applied to knock down NSBP1 expression in the PCa cell line DU145 by lentiviral plasmids producing an NSBP1 small hairpin RNA. After NSBP1 knockdown in DU145 cells, the growth rate of cells was analyzed by MTT, and G2/M cell cycle arrest and apoptosis were assessed using a FAC- Scalibur flow cytometer. Tumour growth was assessed in nude mice. The mRNA and protein expression levels of NSBP1, cyclin B1 and Bcl-2 were analysed in vitro and in vivo by reverse-transcriptase polymerase chain reaction and Western blotting. Knockdown of NSBP1 resulted in a 22.6% decrease in the growth rate of cells compared with the PscNC lentivirus control cells at 96 h, decreased tumour growth in nude mice, and the induction of Gz/M cell cycle arrest （8.78%） and apoptosis （2.19-fold）. Consistent with the cell cycle arrest and apoptosis, the mRNA and protein expression levels of cyclin B 1 and Bcl-2 were decreased. In conclusion, knockdown of NSBP 1 causes a statistically significant inhibition of the in vitro and in vivo growth of the PCa cell line DU145. Growth suppression is at least partially due to NSBP1 knockdown-induced Gz/M cell cycle arrest and apoptosis. The present data provide the evidence that the NSBP1 knockdown-induced G2/M phase arrest and apoptosis may result from negative regulation of cyclin B 1 and Bcl-2 by NSBP1, with the resulting reduced expression of these proteins.

Role of stromal cell-derived factor 1α pathway in bone metastatic prostate cancer

Metastatic prostate cancer is one of the leading causes of cancer-related death in men. The primary site of metastasis from prostate cancers is the bone. During the last decade, multiple studies have pointed to the role of the stromal cell-derived factor 1 alpha （SDF 1 a）/CXCR4 axis in the metastatic spread of the disease, but the mechanisms that underlie this effect are still incompletely understood. In this review, we summarize the current understanding of the role of the SDF 1a/CXCR4 pathway in bone metastatic prostate cancer. We also discuss the therapeutic potential of disrupting the interaction between prostate tumor cells and bone environment with focus on the SDF1a pathway.

The role of BRCA 1 and BRCA2 in prostate cancer

One of the strongest risk factors for prostate cancer is a family history of the disease. Germline mutations in the breast cancer predisposition gene 2 （BRCA2） are the genetic events known to date that confer the highest risk of prostate cancer （8.6-fold in men ≤ 65 years）. Although the role of BRCA2 and BRCA1 in prostate tumorigenesis remains unrevealed, deleterious mutations in both genes have been associated with more aggressive disease and poor clinical outcomes. The increasing incidence of prostate cancer worldwide supports the need for new methods to predict outcome and identify patients with potentially lethal forms of the disease. As we present here, BRCA germline mutations, mainly in the BRCA2gene, are one of those predictive factors. We will also discuss the implications of these mutations in the management of prostate cancer and hypothesize on the potential for the development of strategies for sooradic cases with similar characteristics.

Vascular endothelial growth factor A, secreted in response to transforming growth factor-β1 under hypoxic conditions, induces autocrine effects on migration of prostate cancer cells

Hypoxia and transforming growth factor-β1 （TGF-β1） increase vascular endothelial growth factor A （VEGFA） expression in a number of malignancies. This effect of hypoxia and TGF-β1 might be responsible for tumor progression and metastasis of advanced prostate cancer. In the present study, TGF-β1 was shown to induce VEGFA165 secretion from both normal cell lines （HPV7 and RWPE1） and prostate cancer cell lines （DU 145 and PC3）. Conversely, hypoxia-stimulated VEGFA165 secretion was observed only in prostate cancer cell lines. Hypoxia induced TGF-β1 expression in PC3 prostate cancer cells, and the TGF-β1 type I receptor （ALK5） kinase inhibitor partially blocked hypoxia-mediated VEGFA16s secretion. This effect of hypoxia provides a novel mechanism to increase VEGFA expression in prostate cancer cells. Although autocrine signaling of VEGFA has been implicated in prostate cancer progression and metastasis, the associated mechanism is poorly characterized. VEGFA activity is mediated via VEGF receptor （VEGFR） 1 （Fit-l） and 2 （FIk-I/KDR）. Whereas VEGFR-1 mRNA was detected in normal prostate epithelial cells, VEGFR-2 mRNA and VEGFR protein were expressed only in PC3 cells. VEGFA165 treatment induced phosphorylation of extracellular signal-regulated kinase 1/2 （ERKI/2） in PC3 cells but not in HPV7 cells, suggesting that the autocrine function of VEGFA may be uniquely associated with prostate cancer. Activation of VEGFR-2 by VEGFA165 was shown to enhance migration of PC3 cells. A similar effect was also observed with endogenous VEGFA induced by TGF-β1 and hypoxia. These findings illustrate that an autocrine loop of VEGFA via VEGFR-2 is critical for the tumorigenic effects of TGF-β1 and hypoxia on metastatic prostate cancers.

Histone methyltransferase SETDB1 is required for prostate cancer cell proliferation, migration and invasion

SETDB1 has been established as an oncogene in a number of human carcinomas. The present study was to evaluate the expression of SETDB1 in prostate cancer （PCa） tissues and cells and to preliminarily investigate the role of SETDB1 in prostate tumorigenesis in vitro. Quantitative reverse transcription polymerase chain reaction （qRT-PCR） and immunohistochemistry （IHC） were used to detect the expression of SETDB1 in PCa tissues, adjacent normal tissues, benign prostatic hyperplasia （BPH） tissues, PCa cell lines and normal prostate epithelial cells. The results suggested that SETDB1 was upregulated in human PCa tissues compared with normal tissues at the mRNA and protein levels. The role of SETDB1 in proliferation was analyzed with cell counting kit-8, colony-forming efficiency and flow cytometry assays. The results indicated that downregulation of SETDB1 by siRNA inhibited PCa cell growth, and induced GO/G1 cell cycle arrest. The PCa cell migration and invasion decreased by silcencing SETDBt which were assessed by using in vitro scratch and transwell invasion assay respectively. Our data suggested that SETDB1 is overexpressed in human PCa. Silencing SETDB1 inhibited PCa cell proliferation, migration and invasion.

Joint effect among p53, CYP1A1, GSTM1 polymorphism combinations and smoking on prostate cancer risk： an exploratory genotype-environment interaction study

Aim： To assess the role of several genetic factors in combination with an environmental factor as modulators of prostate cancer risk. We focus on allele variants of low-penetrance genes associated with cell control, the detoxification processes and smoking. Methods： In a case-control study we compared people carrying p53cd72 Pro allele, CYP1A1 M1 allele and GSTM1 null genotypes with their prostate cancer risk. Results： The joint risk for smokers carrying Pro^＊ and MI^＊, Pro^＊ and GSTM1null or GSTM1 null and CYP1A1 MI^＊ variants was significantly higher （odds ratio [OR]： 13.13, 95% confidence interval [CI]： 2.41-71.36; OR： 3.97, 95% CI： 1.13-13.95 and OR： 6.87, 95% CI： 1.68-27.97, respectively） compared with that for the reference group, and for non-smokers was not significant. OR for combinations among p53cd72, GSTM1 and CYP1A1 M1 in smokers were positively and significantly associated with prostate cancer risk compared with non-smokers and compared with the putative lowest risk group （OR： 8.87, 95% CI： 1.25-62.71）. Conclusion： Our results suggest that a combination of p53cd72, CYP1A1, GSTM1 alleles and smoking plays a significant role in modified prostate cancer risk on the study population, which means that smokers carrying susceptible genotypes might have a significantly higher risk than those carrying non-susceptible genotypes.

Prostate cancer risk and aggressiveness associated with the CYPIB1 4326C/G （Leu432Val） polymorphism： a meta-analysis of 2788 cases and 2968 controls

To derive a precise estimation of the associations between the cytochrome P450 1B 1 （CYPIB1） 4326C/G variants and prostate cancer （PCa） risk or aggressiveness, a meta-analysis was performed using all eligible published studies. Odds ratios （ORs） with 95% confidence intervals （CIs） were estimated to assess the association in seven literature studies with 2788 cases and 2968 controls. In the overall analysis, no significant association was found between the CYPIB1 4326C/G polymorphism and PCa risk, but ethnicity subgroup analyses and a case-source analysis revealed significant associations. The 4326G allele showed a significant association with increased PCa risk in Asians （OR= 1.52, 95% Ch 1.20-1.92）, and significant associations were also observed in a heterozygote comparison （OR= 1.40, 95% Ch 1.03-1.89）, a homozygote comparison （0R=2.38, 95% Ch 1.31-4.33） and in a dominant genetic model （OR = 1.52, 95% Ch 1.14-2.01）. Moreover, the 4326G allele was also significantly correlated with an increased risk of sporadic PCa （OR= 1.13, 95% Ch 1.04-1.24）, and significant associations were observed in a heterozygote comparison （OR= 1.16, 95% Ch 1.02-1.33）, a homozygote comparison （OR= 1.24, 95% Ch 1.03-1.49） and a dominant genetic model （OR= 1.19, 95% Ch 1.05- 1.34）. The overall analyses and all subgroup analyses showed no significant association between the 4326C/G polymorphism and PCa aggressiveness. Our meta-analysis showed that CYPIB1 4326G allele is significantly associated with an increased PCa risk in Asians and in sporadic PCa cases.

Small ubiquitin-like modifier protein-specific protease 1 and prostate cancer

Small ubiquitin-like modifier protein （SUMO） modification is a highly dynamic process, catalyzed by SUMO- specific activating （El）, conjugating （E2） and ligating （E3） enzymes, and reversed by a family of SUMO-specific proteases （SENPs）. There are six members of the human SENP family, and each SENP has different cellular locations and substrate specificities. However, the precise roles of SENPs in cellular processes have not been elucidated to date. This brief review will focus on recent advances pertaining to the identified targets of SENP 1 and its potential role in prostate cancer.

Relationship between XRCC1 polymorphisms and susceptibility to prostate cancer in men from Han, Southern China

Aim： To investigate the association among XRCC1 polymorphisms, smoking, drinking and the risk of prostate cancer （PCa） in men from Han, Southern China. Methods： In a case-control study of 207 patients with PCa and 235 cancerfree controls, frequency-matched by age, we genotyped three XRCC1 polymorphisms （codons 194, 280 and 399） using the polymerase chain reaction-restriction fragment length polymorphism （PCR-RELP） method. Results： Among the three polymorphisms, we found that the XRCC1 Arg399Gln variant allele was associated with increased PCa risk （adjusted odd ratio [OR]： 1.67, 95% confident interval [CI]： 1.11-2.51）, but the XRCC1 Arg 194Trp variant allele had a 38% reduction in risk of PCa （adjusted OR： 0.62, 95% CI： 0.41-0.93）. However, there was no significant risk of PCa associated with Arg280His polymorphism. When we evaluated the three polymorphisms together, we found that the individuals with 194Arg/Arg wild-type genotype, Arg280His and Arg399Gln variant genotypes had a significantly higher risk of PCa （adjusted OR： 4.31; 95% CI： 1.24-14.99） than those with three wild-type genotypes. In addition, we found that Arg399Gln variant genotypes had a significant risk of PCa among heavy smokers （adjusted OR： 2.04; 95% CI： 1.03-4.05）. Conclusion： These results suggest that polymorphisms of XRCC1 appear to influence the risk of PCa and may modify risks attributable to environmental exposure.

Anti-tumor Activity of Curcumin against Androgen-independent Prostate Cancer Cells via Inhibition of NF-κB and AP-1 Pathway in vitro

The anti-tumor activity of curcumin against androgen-independent prostate cancer cells in vitro and the possible mechanism were investigated.After curcumin treatment,the effect of curcumin on the proliferation of prostate cancer PC-3 cells was assessed by CFSE staining.Flow cytometery（FCM） was performed to analyze the cell cycle and the induction of apoptosis of tumor cells.A luciferase reporter gene assay was used to determine the effects of curcumin on the activities of intracellular NF-κB and AP-1 signaling pathways.The results showed curcumin could effectively inhibit the proliferation of PC-3 cells in vitro（P0.05）.Cells were arrested at G2/M phase.After curcumin treatment,the percentage of apoptotic cells was significantly higher than in control group（P0.05）.The results of the luciferase assay revealed that curcumin selectively inhibited the activities of the NF-κB and AP-1 signaling pathways in PC-3 cells significantly.It was suggested that curcumin could exert anti-tumor activity against androgen-independent prostate cancer cells in vitro by inhibiting cellular proliferation and inducing apoptosis,which was probably contributed to the inhibition of transcription factors NF-κB and AP-1.

Contragestazol (DL111-IT) inhibits proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo

Aim： To evaluate the antiproliferative activity of contragestazol （DL111-IT） on the human prostate cancer cell line PC3 in vitro and in vivo and to elucidate its potential molecular mechanisms. Methods： The cell killing ability of DL111-IT was measured by the 3-（4,5-dimethylthia-zol,2-yl）-2,5-diphenyltetrazolium bromide （MTT） reagent assay method and the tumor xenograft model. The cell cycle was analyzed by flow cytometry and protein expression, including retinoblastoma （pRb）, cyclin-dependent kinase 4 （CDK4） and cyclin D 1, was detected by Western blotting. Results： DL111-IT exhibited high efficiency on cell growth inhibition of the human androgen-independent prostate cancer cell line PC3. The drug concentration that yielded 50 % cell inhibition （IC50 value） was 9.9 mg/mL. In the PC3 tumor xenograft study, DL111-IT （1.25 mg/kg-20.0 mg/kg） given once a day for 10 days significantly inhibited tumor growth, with the inhibition rate ranging from 21% to 50 %. Flow cytometric analysis indicated that DL111-IT could cause GI arrest in the PC3 cell line, but not apoptosis. DL111-IT enhanced pRb expression and down-regulated CDK4 and cyclin D 1 expression, suggesting that cell cycle regulation might contribute to the anticancer property of DL 111- IT. Conclusion： DL111-1T inhibits the proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo by a cell cycle regulation pathway.

Overexpression of ETS-1 is associated with malignan＇ biological features of prostate cancer

E26 transformation-specific-1 （ETS-1）, an ETS family transcription factor, has been reported to play an important role in a variety of physiological and pathological processes, but clinical implications of ETS-1 expression in prostate cancer （PCa）, particularly high-risk cases, including response to androgen-deprivation therapy （ADT） have yet to be elucidated. We examined the expression of ETS- 1 using immunohistochemical staining of paraffin-embedded prostate carcinoma tissue obtained by needle biopsy from 69 mostly advanced PCa patients. ETS-1 expression was compared with the clinicopathological characteristics of the 69 patients, including 25 who underwent ADT as a primary treatment. As a result, PCa patients with higher expression of ETS-1 were significantly more likely to be of high stage and high Gleason score （P〈O.05）. There was no significant association between ETS-1 expression and the initial prostate-specific antigen （PSA） level. In the 25 patients treated by ADT, the staining score for ETS-1 was significantly associated with rapid development of castration-resistant disease within 24 months （P〈O.05）, whereas the Gleason score and PSA level were not. In conclusion, increased ETS-1 expression was associated with a higher stage, higher Gleason score and shorter time to castration-resistant progression. These data suggest that immunostaining for ETS-1 could be a molecular marker for predicting a poor clinical outcome for PCa patients, oarticularlv those with hi^h-risk disease.

PUM1 represses CDKN1B translation and contributes to prostate cancer progression

Posttranscriptional regulation of cancer gene expression programs plays a vital role in carcinogenesis;identifying the critical regulators of tumorigenesis and their molecular targets may provide novel strategies for cancer diagnosis and therapeutics.Highly conserved RNA-binding protein Pumilio-1(PUM1)regulates mouse growth and cell proliferation,propelling us to examine its role in cancer.We found human PUM1 is highly expressed in a diverse group of cancer,including prostate cancer;enhanced PUM1 expression is also correlated with reduced survival among prostate cancer patients.Detailed expression analysis in twenty prostate cancer tissues showed enhanced expression of PUM1 at mRNA and protein levels.Knockdown of PUM1 reduced prostate cancer cell proliferation and colony formation,and subcutaneous injection of PUM1 knockdown cells led to reduced tumor size.Downregulation of PUM1 in prostate cancer cells consistently elevated cyclin-dependent kinase inhibitor 1B(CDKN1B)protein expression through increased translation but did not impact its mRNA level,while overexpression of PUM1 reduced CDKN1B protein level.Our finding established a critical role of PUM1 mediated translational control,particularly the PUM1-CDKN1B axis,in prostate cancer cell growth and tumorigenesis.We proposed that PUM1-CDKN1B regulatory axis may represent a novel mechanism for the loss of CDKN1B protein expression in diverse cancers and potential targets for therapeutics development.

Association of hypoxia-inducible factor-1α (HIF1α) 1772C/T genepolymorphism with susceptibility to renal cell carcinoma/prostatecancer

In this study,we used a meta-analysis method to evaluate the relationship between hypoxia-inducible factor-1α(HIF1α)1772C/T gene polymorphism(rs 11549465)and renal cell carcinoma(RCC)/prostate cancer risk.We searched for relevant studies(before March 1,2019)on Cochrane Library,Embase,and PubMed.Studies meeting the inclusion criteria were recruited into this meta-analysis.The outcome of dichotomous data was showed in the way of odds ratios(OR),and 95%confidence intervals(CI)were also counted.In this investigation,there was no association between HIF1α1772C/T gene polymorphism and susceptibility to RCC in Caucasians,Asians as well as overall populations.In addition,HIF1α1772C/T gene polymorphism was not found to be relevant to the survival in RCC.Interestingly,the T allele was relevant to prostate cancer risk in all populations,but not in Caucasians and Asians.However,the TT genotype and the CC genotype were not related to prostate cancer susceptibility in Asian,Caucasian,and all populations.In conclusion,the T allele of the HIF1α1772C/T gene polymorphism was related to prostate cancer risk in the overall populations.

Effect of Id1 Knockdown on Formation of Osteolytic Bone Lesions by Prostate Cancer PC3 Cells In Vivo

The formation of osteolytic bone lesions is a key process for osteolytic cancer to metastasize to the bone and is under the control of a set of transcription factors. Recently, the inhibitor of differentiation 1 （Id1） has been linked with angiogenesis, tumorigenesis, metastasis and bone formation. However, the function of Id1 during the process of bone destruction caused by cancer in vivo has not yet been elucidated. We, therefore, examined whether and how Id1 affects the ability of cancer to form osteolytic lesion in vivo. The study used a lentiviral vector overexpressing short hairpin RNA （shRNA） targeting Id1 gene. PC3 cells, a prostate cancer cell line, were transduced with Id1 shRNA or negative control （NC） shRNA before implantation in BALB/c mice. Cells were implanted in a tibial injection model. Tumor formation in bone was monitored by X-ray. The relationship between parathyroid hormone-related protein （PTHrP）, an osteolytic factor, and Id1 was analyzed by using immunohistochemistry in tissue sections from osteolytic lesion of the BALB/c mice. Our results showed that Id1 shRNA delivery to PC3 cells by lentivirus caused efficient and stable Id1 gene silencing. In the intratibial model, PC3 cells produced primarily osteolytic lesions in the bone. Eleven of 14 mice in Id1 shRNA group but only 4 of 14 mice in the NC shRNA group developed osteolytic lesions with cortical destruction at 4th week. Mice treated with Id1 shRNA had larger tumor volume in the bone and larger cortical destruction. The expression of PTHrP protein in PC3 cells was not affected by Id1 knockdown in vivo. These results indicate that Id1 may down-regulate the ability of PC3 cells to form osteolytic lesions in vivo and the signal pathway needs to be further investigated.

Prognostic Value of Promoter Hypermethylation of Retinoic Acid Receptor Beta (RARB) and CDKN2 (p16/MTS1) in Prostate Cancer

Objective: The molecular mechanism of prostate cancer is poorly understood. The aim of the study was to investigate the prevalence and prognostic value of promoter hypermethylation of retinoic acid receptor beta (RARB) and p16 among benign prostatic hyperplasia (BPH) and prostate cancer patients. Methods: In this case-control study, 63 patients were included in three groups; 21 with BPH as the control group, 21 with prostate cancer and good prognostic factors (based on prostate-specific antigen, Gleason score and stage) as good prognosis group, and 21 with prostate cancer and poor prognostic features as poor prognosis group. The prostate biopsy specimen of each individual was examined for hypermethylation of RARB and p16 promoters by methylation specific PCR (MSPCR). Results: Seven (33.3%) patients with good prognosis and 15 (71.4%) patients with poor prognosis were positive for RARB methylation, which were significantly higher than controls (P <0.0001). p16 promoter methylation was shown in 19.0% and 47.6% patients with good and poor prognosis, respectively. The RARB and p16 promoter methylation in the poor prognosis group was significantly higher than that in the good prognosis group (P =0.02 for RARB and P<0.0001 for p16). Conclusion: Hypermethylation of RARB and p16 promoters may predict prognosis in prostate cancer.