Metallothionein is up-regulated under hypoxia and promotes the survival of human prostate cancer cells

Tumor hypoxia is a common feature of several cancers, including prostate cancer, and is associated with tumor progression, acquisition of anti-apoptotic potential and therapeutic resistance. We explored hypoxia-inducible genes and examined the effect of knockdown of a target molecule with small interference RNA (siRNA) on the proliferation of human prostate cancer cells. Human prostate cancer cell lines (LNCaP and PC-3) were cultured in normoxia (21% O2) or hypoxia (0.5% O2). Hypoxia-inducible genes were identified by cDNA microarray analysis. Metallothionein (MT) expression was assessed by real-time RT-PCR, Western blot analysis and immunohistochemical staining. siRNA was transfected to knock down MT expression, and the cell cycle and apoptosis were evaluated by flow cytometry analysis. In cDNA microarray analysis, 22 genes (including MT) were up-regulated under hypoxia. MT-1X and MT-2A were up-regulated in real-time RT-PCR. In particular, MT-2A was increased 3-fold in LNCaP and 8-fold in PC-3. The siRNA-MT-2A treatment resulted in a 20% inhibition of cell growth and induced apoptosis in both LNCaP and PC-3. In human prostate tissue, intense staining of MT was observed in cancer cells and residual cancer cells after androgen ablation therapy, while normal tissue was only stained in patches. In conclusion, MT was up-regulated under hypoxia in prostate cancer cells and overexpressed in prostate cancer tissue and residual cancer cells after androgen ablation therapy. As down-regulation of MT by siRNA inhibited cell growth and induced cell death, MT may be a new molecular target for the treatment of human prostate cancer.     

Expression of c-erb B-2/neu proto-oncogene in human prostatic cancer tissues and cell lines.

Both amplification and overexpression of c-erb B-2/neu have been associated with the progression and possible prognosis of a number of human cancers. In this study, we demonstrated that c-erb B-2/neu may also play an important role in human prostate cancer. Our conclusion is based on the following observations: (1) A monoclonal antibody raised against a peptide sequence from the C-terminal domain of the human c-erb B-2/neu gene product reacted positively with 68.7% (11 of 16) of the human prostatic cancer tissue extracts analyzed by western blot procedure. These results were supported by the immunohistochemical staining of the prostatic cancer specimens; 80% (12 of 15) showed positive staining, primarily around the plasma membranes of the prostatic cancer cells. c-erb B-2/neu oncoprotein was not detectable in normal prostate tissues (five examined by immunohistochemical staining and three by western blotting) or in human benign prostatic hyperplasia (two examined by immunohistochemical staining and six by western blotting) and was expressed less abundantly with lower intensity in "normal" human prostate tissues adjacent to cancerous prostate tissue (5 of 12 examined by immunohistochemical staining). We observed no evidence of c-erb B-2/neu gene amplification in 10 fresh human prostatic cancer specimens examined by Southern blotting and in the cultured human prostatic cancer cell lines PC-3, DU-145, and LNCaP. (2) The c-erb B-2/neu protein was detected in both androgen-receptor-positive (LNCaP) and -negative (PC-3 and DU-145) human prostate cancer cell lines. Positive immunostaining of c-erb B-2/neu protein was found to be associated predominantly with the plasma membranes of PC-3 cells, but was also found to be widespread in the cytoplasmic region of the LNCaP cells and in the perinuclear region of the DU-145 cells. (3) Like prostate-specific antigen (PSA) expression, c-erb B-2/neu mRNA expression was also positively regulated by androgen in androgen-receptor-positive LNCaP cells in vitro and LNCaP tumors in vivo. When LNCaP tumors were grown in castrated male hosts, levels of c-erb B-2/neu and PSA mRNA expression decreased initially, but rebounded at 3 wk to levels comparable to those expressed by tumors maintained in intact adult male hosts.     

Inhibition of Ca(2+)-activated Cl(-) channel ANO1/TMEM16A expression suppresses tumor growth and invasiveness in human prostate carcinoma

The etiology of prostatic adenocarcinoma remains unclear. Prostate cancer cells of varying metastatic potential and apoptotic resistance show altered expression of plasma membrane ion channels and unbalanced Ca(2+) homeostasis. Ca(2+)-activated Cl(-) channels (CaCCs) are robustly expressed in epithelial cells and function to regulate epithelial secretion and cell volume for maintenance of ion and tissue homeostasis in proliferation, differentiation and apoptosis. ANO1/TMEM16A was recently identified as a CaCC, and it is of interest to determine whether ANO1 plays a role in development and metastasis of prostate carcinoma. Here we show that ANO1 mRNA and protein are highly expressed in human metastatic prostate cancer LNCaP and PC-3 cells by quantitative analysis of real-time PCR and Western blot. These findings were confirmed by whole-cell patch clamp recording of LNCaP and PC-3 cells with increased current density of ANO1 channels. Immunohistochemistry staining further revealed overexpression of ANO1 in human prostate cancer tissues, which correlated with the clinical TNM stage and Gleason score. Experiments with small hairpin RNAs (shRNAs) targeting human ANO1 resulted in a significant reduction of proliferation, metastasis and invasion of PC-3 cells using WST-8, colony formation, wound-healing and transwell assays. Moreover, intratumoral injection of ANO1 shRNA completely inhibited established tumor growth and survival in orthotopic nude mice implanted with PC-3 cells. Our findings provide compelling evidence that upregulation of CaCC ANO1 is involved in the proliferation, progression and pathogenesis of metastatic prostate cancer. Membrane ANO1 protein may therefore serve as a biomarker, and inhibition of overexpressed ANO1 has potential for use in prostate cancer therapy.     

Evidence for prostate cancer-associated diagnostic marker-1: immunohistochemistry and in situ hybridization studies.

PURPOSE: The purpose of this study was to characterize a novel gene/protein associated with prostate cancer, termed prostate cancer-associated diagnostic marker-1 [PCADM-1 (Hu Y, Wang M, Garcia FU, Aoyaki K, Stearns ME. Identification of PCADM-1 as a novel diagnostic marker for prostate cancer, submitted for publication)]. EXPERIMENTAL DESIGN AND RESULTS: Immunological studies revealed that rabbit polyclonal antibodies generated against recombinant PCADM-1 specifically recognize the protein in crude protein extracts from a variety of prostate cancer cell lines (i.e., PC-3 ML, LNCaP, DU145, and CPTX-1532) and prostate cancer tissue. Combined immunolabeling and in situ hybridization studies demonstrated that PCADM-1 mRNA was expressed by the luminal epithelial cells of prostate cancer glands and was not expressed by high-grade prostatic intraepithelial neoplasia or HPV-MLC7 cells. Immunolabeling studies of tissue arrays from biopsies of archival material (n = 200 samples) confirmed that PCADM-1 was expressed by the luminal epithelial cells of prostate cancer. CONCLUSIONS: Taken together, the data suggest that PCADM-1 is a specific marker for human prostate cancer.     

PC-1基因表达对前列腺癌细胞迁移能力的影响

背景与目的:PC-1基因在雄激素非依赖和高转移能力的前列腺癌C4-2细胞中高表达,在雄激素依赖及不转移的前列腺癌LNCaP细胞中低表达。本实验旨在研究PC-1对前列腺癌细胞迁移能力的影响。方法:构建PC-1稳定高表达的LNCaP细胞株和反义核酸调低内源性PC-1表达的C4-2细胞株。利用体外迁移系统检测PC-1表达对LNCaP和C4-2细胞迁移运动能力的影响。结果:体外迁移实验表明稳定转染提高PC-1的表达水平并未使LNCaP迁移细胞数增多(P>0.05),而反义核酸降低PC-1表达则使C4-2迁移细胞数降低(P<0.05)。PC-1蛋白水平升高不能提高LNCaP细胞迁移能力,但降低内源性PC-1表达则使C4-2细胞迁移能力明显降低。结论:PC-1可能在前列腺癌细胞侵袭过程中起一定作用。     

Tazarotene-induced gene 1 (TIG1) expression in prostate carcinomas and its relationship to tumorigenicity

BACKGROUND: Prostate cancer is the most common noncutaneous male cancer and one of the least understood malignant diseases. Identifying key genetic factors involved in the metastasis of prostate cancer cells is critical. In this study, we used selective subtractive differential gene display to identify a gene whose decreased expression may contribute to the growth and expansion of prostate cancer. METHODS: We used 192 primer pair combinations and polymerase chain reaction technology to identify genes expressed in the benign prostate cell line PNT-2 but not in the malignant prostate cancer cell lines LNCaP, Du-145, PC-3, or PC-3M. The tazarotene-induced gene 1 (TIG1) was chosen for further study. TIG1 expression in normal tissues and cell lines was analyzed by northern blot and in normal and tumor prostate tissue sections by in situ hybridization. The in vitro invasiveness (migration through extracellular matrix) and in vivo tumorigenicity (growth in nude mice) were assessed for the highly malignant PC-3M cell line transfected with TIG1 or control cDNA. All statistical tests were two-sided. RESULTS: TIG1 mRNA was expressed in a variety of normal tissues other than prostate tissue. TIG1 mRNA was detected in all 10 normal human prostate tissues and all 51 benign prostatic hyperplastic tissues analyzed but in only four of 51 malignant prostate tissues analyzed. Compared with vector-transfected cells, transfection of PC-3M cells with TIG1 decreased in vitro invasiveness from 14.7% to 3.7%, (mean difference = 11%; 95% confidence interval [CI] = 9.2% to 12.8%, P<.001) and decreased in vivo tumorigenicity from an average tumor weight of 1.31 g to 0.55 g, (mean difference = 0.76 g; 95% CI = 0.43 to 1.09 g, P<.001). CONCLUSION: TIG1 may be a tumor suppressor gene whose diminished expression is involved in the malignant progression of prostate cancer.     

雷公藤红素对人前列腺癌细胞凋亡及SENP1基因表达的影响

目的：研究雷公藤红素对人前列腺癌（PCa）细胞生长、凋亡及SUMO特异蛋白酶1（SUMO-specificproteases 1,SENP1）基因表达的影响。方法：对前列腺癌细胞PC-3和LNCaP进行雷公藤红素处理,通过测定细胞生长曲线,荧光染色,荧光显微镜观察,流式细胞仪分析和实时定量PCR,检测雷公藤红素对前列腺癌细胞生长、凋亡及SENP1 mRNA表达水平的影响。结果：雷公藤红素能够显著抑制PCa细胞的生长,并且抑制作用呈剂量依赖性;雷公藤红素能够诱导PCa细胞凋亡,1μmol/L雷公藤红素处理24h诱导14.8%的PC-3细胞和23.2%的LNCaP细胞发生凋亡或死亡;雷公藤红素还能够降低PCa细胞中SENP1 mRNA水平,尤其是PC-3细胞。结论：雷公藤红素能够显著抑制PCa细胞的生长并诱导细胞凋亡,表明雷公藤红素具有抗前列腺癌作用,雷公藤红素能够降低PCa细胞中SENP1 mRNA水平,揭示雷公藤红素可能通过SENP1相关信号通路达到抗前列腺癌作用。     

血管内皮生长因子及其受体KDR在前列腺癌细胞中的表达研究

目的:探讨血管内皮生长因子(vascular endothelial growthfactor,VEGF)及其受体(KDR)在前列腺癌细胞中的表达及意义.方法:免疫细胞化学和Western blot检测体外培养的LNCaP,PC-3,PC-3M,DU-145和22RV1前列腺癌细胞中VEGF及其受体KDR的蛋白表达,RT-PCR检测mRNA,ELISA检测前列腺癌细胞培养上清VEGF蛋白含量.结果:免疫细胞化学染色显示VEGF和KDR在前列腺癌细胞LNCaP,PC-3,PC-3M,DU-145和22RV1中均有表达,但表达水平略有差别.LNCaP,PC-3和DU-145细胞中VEGF和KDR蛋白表达及其mRNA的含量显著高于PC-3M和22RV1(P＜0.01).细胞培养上清中VEGF蛋白含量结果与免疫细胞化学染色结果相同.结论:VEGF及其受体KDR在前列腺癌细胞中的表达量不近相同,但二者的表达对研究前列腺癌的发生发展及其机理有重要意义.     

Characterization of a zinc-finger protein and its association with apoptosis in prostate cancer cells

BACKGROUND: The transition from androgen-dependent to androgen-independent prostate cancer is not fully understood but appears to involve multiple genetic changes. We have identified a gene, GC79, that is more highly expressed in androgen-dependent LNCaP-FGC human prostate cancer cells than in androgen-independent LNCaP-LNO human prostate cancer cells. Physiologic levels (0.1 nM:) of androgens repress expression of GC79 messenger RNA (mRNA) in LNCaP-FGC cells. To determine the role of GC79, we cloned its complementary DNA (cDNA) and functionally characterized its product. METHODS: The differentially expressed GC79 gene was cloned from human prostate cDNA libraries, sequenced, and transfected into mammalian cells to study its function. Expression of GC79 was analyzed in various adult and fetal human tissues and in prostate glands of castrated rats. The association of GC79 expression and apoptosis was investigated in COS-1 and LNCaP cells transfected with GC79 cDNA. All statistical tests are two-sided. RESULTS: Sequence analysis indicates that GC79 encodes a large, complex, multitype zinc-finger protein, containing nine C(2)H(2)-type zinc-finger domains, a cysteine-rich region, and a GATA C(4)-type zinc-finger domain. Castration-induced androgen withdrawal increased the expression of GC79 mRNA in the regressing rat ventral prostate, suggesting that the expression of GC79 mRNA is associated with the process of apoptotic cell death in the rat ventral prostate. Transfection and induction of GC79 cDNA in both COS-1 and LNCaP prostate cancer cells led to an apoptotic index that was eightfold higher (P:<.001, two-sided Student's t test) than that observed in uninduced transfected cells. CONCLUSIONS: We have cloned an androgen-repressible gene, GC79, that is potentially involved in apoptosis. This finding may have implications for the development of androgen-independent prostate cancer and, ultimately, for the treatment of prostate cancer.     

Antiproliferative effects of AVN944, a novel inosine 5-monophosphate dehydrogenase inhibitor, in prostate cancer cells

Inosine 5-monophosphate dehydrogenase II, a key enzyme in the de novo synthesis of purine nucleotides, is expressed in prostate tumors and prostate cancer cells. AVN944 is a new, specific, noncompetitive IMPDH inhibitor. In this study, we investigated the effects of IMPDH inhibitor AVN944 on LNCaP, CWR22Rv1, DU145 and PC-3 human prostate cancer cells. AVN944 inhibited proliferation of these 4 prostate cancer cell lines and was associated with cell cycle G1 arrest of LNCaP cells and S-phase block of androgen-independent CWR22Rv1, DU145 and PC-3 cells. AVN944 induced caspase-dependentand caspase-independent cell death in LNCaP, CWR22Rv1, and DU145 cells. AVN944 induced expression of p53-target proteins Bok, Bax and Noxa in androgen-responsive cell lines and suppressed expression of survivin in prostate cancer cells regardless of their androgen sensitivity. AVN944 also induced differentiation of androgen-independent prostate cancer cells as indicated by morphological changes and increased expression of genes coding for prostasomal proteins, keratins and other proteins, including tumor suppressor genes MIG-6 and NDRG1. AVN944-differentiated androgen-independent DU145 and PC-3 cells are sensitized to TRAIL-induced apoptosis as demonstrated by induction of caspases and PARP cleavage. In summary, AVN944 inhibited the growth of human prostate cancer cells by inducing cell cycle arrest, cell death as well as differentiation. AVN944 is a novel, promising therapeutic agent that might be combined with other agents for treatment of human prostate cancer.     

lncRNA FLJ26245 通过 miR-200a-3p/PTPRG 轴调控前列腺癌 PC-3 细 胞的增殖与迁移

目的：探讨lncRNA FLJ26245在前列腺癌组织和细胞中的表达及其对PC-3细胞增殖与迁移能力的影响及其分子机 制。方法：选用2017年3月至2019年5月在洛阳中心医院手术切除的52例前列腺癌及相应的癌旁组织标本,以及前列腺细胞系 LNCaP、C4-2B、PC-3、DU-145和正常前列腺上皮细胞RWPE-1,用qPCR法检测前列腺癌组织和细胞中FLJ26245的表达水平。分 别将FLJ26245 mimic和阴性对照质粒（lncR-NC）转染到PC-3细胞中,用MTT法、细胞划痕愈合实验分别检测细胞的增殖和迁移 能力。生物信息学技术预测和双荧光素酶基因报告实验验证FLJ26245与miR-200a-3p、酪氨酸磷酸酶受体G（PTPRG）三者之间 的靶向关系。用qPCR 和 WB 法分别检测 FLJ26245 下游基因及增殖与迁移相关蛋白的表达。结果：FLJ26245 在前列腺癌组 织和细胞中的表达水平分别显著低于癌旁组织（P<0.01）和 RWPE-1细胞（P<0.01或P<0.05）,以PC-3细胞中的表达水平为最低（P<0.01）。FLJ26245过表达可明显抑制PC-3细胞的增殖和迁移能力（P<0.05或P<0.01）。FLJ26245可与miR-200a-3p靶向结 合,miR-200a-3p可与PTPRG靶向结合（均P<0.01）。FLJ26245过表达的PC-3细胞中miR-200a-3p表达水平显著降低（P<0.01）、PTPRG mRNA和蛋白表达水平均明显升高（均P<0.01）,细胞中增殖和迁移相关蛋白cyclin A、CDK2和Twist、N-cadherin均显著 降低（均P<0.01）。结论：FLJ26245在前列腺癌组织及细胞中均低表达,其可能通过miR-200a-3p/PTPRG轴调控前列腺癌PC-3 细胞的增殖与迁移能力。     

S100A6 (Calcyclin) is a prostate basal cell marker absent in prostate cancer and its precursors

S100A6 (Calcyclin) is a calcium-binding protein that has been implicated in a variety of biological functions as well as tumorigenesis. The aim of our study was to investigate the involvement of S100A6 during prostate cancer development and progression. Using immunohistochemistry, the expression of S100A6 was examined in benign (n=66), premalignant (n=10), malignant (n=66) and metastatic prostate (n=5) tissues arranged in a tissue-microarray or whole sections as well as in prostate cancer cell lines. The S100A6 immunostaining pattern in tissues was compared with that of cytokeratin 5 (a basal cell marker) and 18 (a benign luminal cell marker). In all cases of benign epithelium, intense S100A6 expression was seen in the basal cell layer with absent staining in luminal cells. In all cases of prostatic adenocarcinoma (matched), metastatic lesions and 3/10 high-grade prostatic intraepithelial neoplasia lesions, an absence of S100A6 was seen. Western blotting and RT-PCR analysis of cell lines showed S100A6 expression to be absent in LNCaP, LNCaP-LN3 and LNCaP-Pro5 but present in Du145, PC3, PC-3M and PC-3M-LN4. LNCaP cells treated with 5-Azacytidine, caused re-expression of S100A6 mRNA. Sequencing of bisulphite modified DNA showed CpG methylation within the S100A6 promoter region and exon 1 of LNCaP, LNCaP-LN3 and LNCaP-Pro5 cell lines but not in Du145 cells. Our data suggest that loss of S100A6 protein expression is common in prostate cancer development and may occur at an early stage. The mechanism of loss of expression may involve hypermethylation of CpG sites. The finding of intense S100A6 expression in the basal cells of benign glands but loss of expression in cancer could be useful as a novel diagnostic marker for prostate cancer.     

人前列腺特异性抗原启动子调控的CXCR4-siRNA逆转录病毒载体的构建及其对前列腺癌细胞的生物学效应

目的构建人前列腺特异性抗原(hPSA)启动子调控的趋化因子受体4(CXCR4)的RNA干扰逆转录病毒载体,并探讨其对激素依赖性前列腺癌LNCaP细胞CXCR4基因表达的靶向抑制作用。方法PCR扩增CXCR4特异性小干扰RNA(siRNA),转入带有增强型绿色荧光蛋白(EGFP)和启动子U6的pGensil-1质粒,以hPSA启动子代替U6启动子,再将重组基因片段导入到逆转录病毒真核表达载体pLXSN中,进行限制性酶切鉴定。转染。PA317包装细胞,收获病毒上清,分别转染前列腺癌细胞PC-3m、LNCaP和人乳腺癌细胞MCF7。采用RT-PCR、Western blot检测CXCR4基因表达。Transwell小室侵袭实验检测前列腺癌细胞体外侵袭能力的变化。结果通过限制性酶切鉴定该重组质粒,成功构建了CXCR4的RNA干扰质粒pLXSN/EGFP-hPSA-siCXCRd。与空载体组比较,CXCRd-siRNA对LNCaP细胞CXCR4 mRNA和蛋白表达抑制显著,48 h抑制率分别为(81.53±10.22)%和(90.52±9.31)%;对PC-3m、MCF-7细胞CXCRd mRNA和蛋白表达无抑制作用。Transwell侵袭实验结果显示,LNCaP细胞干扰组微膜下孔细胞数为(139.9±14.2)个,空载体组为(348.4±36.4)个,两组差异有统计学意义(P<0.05);PC-3m、MCF-7细胞干扰组微膜下孔细胞数与空载体组比较,差异无统计学意义(P>0.05)。结论该逆转录病毒系统中,hPSA启动子调控的下游RNA干扰序列特异性地抑制激素依赖前列腺肿瘤细胞的CXCR4基因表达,具有明显的靶向性。hPSA启动子调控的靶向CXCRd基因的RNA干扰技术在激素依赖性前列腺癌的基因治疗中具有一定价值。     

Metastatic model for human prostate cancer using orthotopic implantation in nude mice.

BACKGROUND: Understanding the mechanism of prostate cancer metastasis is essential to the design of a more effective therapy. An effective therapy for this disease will depend on the development of a clinically relevant in vivo model. PURPOSE: We describe the development of such a model by using orthotopic implantation of human prostate cells in BALB/c nude mice. METHOD: We compared the tumorigenicity of and the incidence of metastasis of human prostate cancer PC-3M and LNCaP-FGC (LNCaP) cell lines subsequent to prostatic (orthotopic) or subcutaneous (ectopic) implantations in male nude mice. RESULTS: LNCaP cells produced tumors only in the prostate. Enhanced tumorigenicity at the orthotopic site was found for PC-3M cells. Lymph node metastases were observed in practically all mice given an injection of PC-3M cells in the prostate, but they were uncommon with subcutaneous injection of these cells. Bilateral orchiectomy did not alter the tumorigenicity of either PC-3M or LNCaP cells or the incidence of lymph node metastasis by PC-3M cells. LNCaP tumors in the mouse prostate (but not PC-3M tumors) elaborated detectable levels of human prostate-specific antigen (PSA) in the serum, even when tumors were small (1.5 mm in diameter). Immunohistochemistry analysis revealed the presence of the PSA marker in tissue sections of LNCaP but not of PC-3M tumors. CONCLUSIONS: The implantation of human prostate cancer cells in an ectopic environment does not permit expression of metastatic potential. In contrast, intraprostatic implantation does. IMPLICATIONS: These data suggest that the orthotopic injection of human prostate cancer cells into the nude mouse may provide a valuable model to study the biology and therapy of human prostate cancer.