Gene expression of angiogenic factors correlates with metastatic potential of prostate cancer cells

We hypothesize that expression of proangiogenic genes correlates with the metastatic potential of prostate cancer cells. LNCaP, DU-145, and PC-3 are prostate cancer cell lines with low, moderate, and high metastatic potential, respectively, as we demonstrated by their capacity to invade an extracellular matrix, an established tumor invasion assay. The constitutive gene expression of the proangiogenic factors, vascular endothelial growth factor, intercellular adhesion molecule-1, interleukin-8, and transforming growth factor-beta2, was significantly greater in the more metastatic DU-145 and PC-3 cells as compared with LNCaP cells. Matrix metalloproteinase (MMP)-9 is thought to contribute to the invasive phenotype of tumor cells. PC-3 cells showed increased expression of MMP-9 and membrane type 4-MMP as compared with LNCaP and DU-145. Tissue inhibitors of metalloproteinase 1 and 4 gene expression were elevated in DU-145 and PC-3 cells, but paradoxically, LNCaP cells had undetectable levels of these genes. We transfected and overexpressed MMP-9 in poorly metastatic LNCaP cells and measured their invasive activity. Transient expression of human MMP-9 in LNCaP cells produced a 3-5-fold increase in MMP-9 activity with a comparable increase in invasiveness. Antisense ablation of the expression of MMP-9 in DU-145 and PC-3 cells produced concomitant inhibition of the gene expression of the proangiogenic factors, vascular endothelial growth factor, and intercellular adhesion molecule-1 (ICAM-1). Treatment of DU-145 and PC-3 cells with a selective chemical inhibitor of MMP-9 proteinase activity also inhibited their invasive activity. These results support our hypothesis that metastatic potential of prostate cancer cells correlates with expression of proangiogenic factors.     

Arachidonate 12-lipoxygenase may serve as a potential marker and therapeutic target for prostate cancer stem cells

The presence of arachidonate 12-lipoxygenase (12-LOX) potentiates prostate cancer (PCa) progression and therefore may be a good therapeutic target and/or a potential diagnostic predictor for PCa. In this study, we examined the expression of 12-LOX in PCa stem cells (PCa SCs) to test if it can serve as a unique marker and therapeutic target for PCa SCs. To this end, we isolated the cancer stem cell-like side population (SP) cells from the human PCa cell line DU-145 by a flow cytometry-based SP technique. The isolated DU-145 SP cells comprised a small population of the DU-145 cells. The SP cells had an up-regulation of ATP-binding cassette sub-family G member 2 (ABCG2) which enables these cells to efflux vital dyes and chemotherapeutic drugs. Furthermore, we detected a strong up-regulation of 12-LOX in these DU-145 SP cells compared to the parental DU-145 cells by RT-PCR and Western blot approaches. We also detected 12-LOX overexpression in PCa SCs in human PCa tissue samples by paraffin-section based immunofluorescent 4-channel confocal microscopy. However, no 12-LOX was detected in normal prostate epithelial SCs in normal prostate tissue samples. These multiple lines of evidence support the possibility that 12-LOX may serve as a unique marker and therapeutic target for PCa SCs.     

Mechanisms controlling cell cycle arrest and induction of apoptosis after 12-lipoxygenase inhibition in prostate cancer cells

Extensive studies have implicated the role of dietary fatty acids in prostatecancer progression. Platelet-type 12-Lipoxygenase (12-LOX) has beenshown to regulate growth, metastasis, and angiogenesis of prostate cancer. The effect of two 12-LOX inhibitors, Baicalein and N-benzyl-N-hydroxy-5-phenylpentamide (BHPP), on the mechanisms controlling cell cycle progression and apoptosis were examined in two prostate cancer cell lines, PC3 and DU-145. Treatment with Baicalein or BHPP resulted in a dose-dependent decrease in cell proliferation, as measured by BrdUrd incorporation. This growth arrest was shown to be because of cell cycle inhibition at G0/G1, and was associated with suppression of cyclin D1 and D3 protein levels. PC3 cells also showed a strong decrease in phosphorylated retinoblastoma (pRB) protein, whereas the other retinoblastoma-associated proteins, p107 and p130, were inhibited in DU-145 cells. Treatment with 12-hydroxyeicosatetraenoic acid in the presence of Baicalein blocked loss of pRB, whereas 12(S)-HETE alone induced pRB expression. Treatment with either Baicalein or BHPP resulted in significant apoptosis in both cell lines as measured by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling. DU-145 cells underwent apoptosis more rapidly than PC-3 cells. The mechanisms involved were decreased phosphorylation of Akt, loss of survivin and subsequent activation of caspase-3 and caspase-7 in each cell line, decreased Bcl-2 and Bcl-X(L) expression in DU-145, and a shift in Bcl-2/Bax levels favoring apoptosis in PC-3 cells. Addition of 12(S)-HETE protected both cell lines from Baicalein-induced apoptosis, whereas other LOX metabolites, 5(S)-HETE, or 15(S)-HETE did not. These results show that the 12-LOX pathway is a critical regulator of prostate cancer progression and apoptosis, by affecting various proteins regulating these processes. Therefore, inhibition of 12-LOX is a potential therapeutic agent in the treatment of prostate cancer.     

Potent tumoricidal effects of a human cytotoxic T-cell line (TALL-104) against prostate cancer

The human TALL-104 cell line possesses major histocompatibility complex non-restricted cytotoxic activity against a large variety of tumor targets. Adequate therapies for prostate cancer that has spread outside its capsule are lacking. In order to identify effective therapies for this problem, we investigated the antiproliferative effects of TALL-104 cells against three prostate cancer cell lines (LNCaP, PC-3, DU-145). A Cr-51-release: cytotoxicity assay showed that TALL-104 cells were very cytotoxic against the prostate cancer cells. For example, at a 1:1 ratio of TALL-104 cells to prostate cancer cells, the percent release of Cr-51 at 18 h were 50, 40, and 45% for LNCaP, PC-3, and DU-145, respectively. Analysis by inhibition of clonogenic growth of prostate cancer cells also showed that TALL-104 cells were extremely effective. For instance, a short-term (4 h or 18 h) pre-incubation of TALL-104 cells with these tumor cells at the effector to target ratio of 10:1 prior to clonogenic assay resulted in a substantial reduction in clonogenic tumor growth (90%, 65%, and 50% clonal growth inhibition for LNCaP, PC-3, and DU-145, respectively). Further experiments using both Cr-51 release and clonogenic assays showed that irradiated TALL-104 cells were also effective in their anti-prostatic cancer activities. We also examined if TALL-104 cells plus a chemotherapeutic agent might complement each other in their cytotoxic effects. Preincubation of prostate cancer cell targets with etoposide (0.2-20 mu g/ml) for 18 h markedly increased their susceptibility to TALL-104 lysis. The anti-tumor efficacy of TALL-104 cells was also demonstrated in vivo utilizing the BNX murine model engrafted with subcutaneous PC-3 prostate cancer cells. A substantial reduction in PC-3 tumor cell progression was observed in mice injected with irradiated TALL-104 cells (1x10(7) cells intraperitoneally or intratumorally for 5 days beginning on days 24 and 45 after implantation) as compared to mice injected with tumors only. Taken together, these findings suggest that TALL-104 cells may be utilized as a potent anti-tumor agent, either alone or in combination with other agents (such as etoposide) in metastatic prostate cancer.     

A comparative study on expression of prostatic inhibin peptide, prostate acid phosphatase and prostate specific antigen in androgen independent human and rat prostate carcinoma cell lines

Prostatic inhibin peptide (PIP), consisting of 94 amino-acid residues is synthesized and secreted by the prostate gland. Previous studies on immuno-histochemical localization of PIP in primary prostatic tumor and their metastasis, have documented the value of this peptide as a tumor marker for diagnosis of prostate cancer (PCa). The present study was undertaken to compare the expression of PIP with that of prostate specific antigen (PSA) and prostatic acid phosphatase (PAP) in androgen independent human PCa cell lines (PC-3, DU-145 and TSU-Prl) by immunoperoxidase technique. The results of the study indicated that the staining for PIP was more intense than that of PSA and PAP. The PSA staining was either weakly positive (PC-3) or totally absent (TSU-Prl and DU-145) while PAP staining was intense in PC-3 and moderate in the other two human cell lines. The intense staining observed for PIP in all of the androgen independent cell lines suggests that the synthesis and secretion of PIP is not primarily dependent on androgens. Furthermore, expression of these markers in Dunning rat cultured adenocarcinoma cell lines and tumors were studied. Positive staining for all three human tumor associated antigens (PIP, PSA and PAP) cross-reacting with the Dunning rat PCa cell lines and the tumors, suggest the suitability of this model for preclinical screening of various therapeutic agents.     

Expression of lipoxygenase in human prostate cancer and growth reduction by its inhibitors

The metabolism of arachidonic acid by either the cyclooxygenase (COX) or lipoxygenase (LOX) pathway generates eicosanoids, which have been implicated in the pathogenesis of a variety of human diseases, including cancer. They are believed to play important roles in tumor promotion, progression, and metastasis. Involvement of LOXs expression and function in tumor growth and metastasis has been reported in human tumor cell lines. Expressions of 5- and 12-LOX in prostate cancer (PC) patients, prostatic intraepithelial neoplasia (PIN), benign prostatic hyperplasia (BPH), and normal prostate (NP) tissues were examined, as well as effects of their inhibitors on cell proliferation in 2 PC cell lines (PC3, DU-145). Expression of 5- and 12-LOX protein was detected by immunohistochemistry. Effects of LOX inhibitors on prostate cancer cell growth were examined by MTT assay, and Hoechst staining was used to determine whether or not the LOX inhibitors induce apoptosis. While 5- and 12-LOX expressions were slightly detected in BPH and NP tissues, marked expressions of 5- and 12-lipoxygenase were detected in PIN and PC tissues. The LOX inhibitors caused marked reduction of prostate cancer cells in a concentration- and time-dependent manner. The LOX inhibitors caused marked inhibition of PC cells through apoptosis. LOX is induced in prostate cancer, and our results suggest that LOX inhibitors may mediate potent antiproliferative effects against prostate cancer cells. Thus, LOX may become a new target in treatment of 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.     

A comparison of the expression of the malignant phenotype in two androgen-independent human prostate cancer cell lines after orthotopic implantation in nude mice

Expression of some features of the malignant phenotype were compared in the DU145 and PC-3M human prostate cancer cell lines after their intraprostatic growth in nude mice. At necropsy, 27/74 (36%) mice injected with DU145 cells and 41/75 (55%) injected with PC-3M cells had either invasive macroscopic tumors, or microscopic intraprostatic tumor cell nests (p = 0.02). Para-aortic lymph node metastases had occurred in 19% of the DU145 cell, and 44% of the PC-3M cell tumor-bearing animals (p = 0.033). Immunohistochemical staining showed high mutant p53 and vascular endothelial growth factor (VEGF) expression by DU145 cells; PC-3M cells did not express detectable p53, and had relatively low VEGF immunohistochemical reactivity. Assays by ELISA established a statistically significant difference in VEGF levels between the cell lines (p < 0.001). Urokinase-like plasminogen activator (uPA) levels, determined by ELISA, were ten-fold higher in the PC-3M cell tumors, as were matrix metalloproteinase-9 (MMP-9) activities assessed by zymography. These findings of high expression of uPA and MMP-9, two key proteolytic enzymes in the invasive/metastatic process, by PC-3M cell prostatic tumors are consistent with their aggressive behavior; the low VEGF levels compared with those in the poorly metastatic DU145 cell tumors suggest that other angiogenic factors may be critical for prostate cancer cell progression in this model.     

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.     

Preclinical studies of gossypol in prostate carcinoma

Hormone refractory prostate cancer remains an incurable disease and the discovery of newer agents with higher cytotoxic activity is required. Gossypol is a phenolic compound isolated from cottonseed oil which has been shown to have anti-spermatogenic effects. In in vitro studies, gossypol appears to inhibit the growth of rat prostate cancer cell line MAT-LyLu and human prostate adenocarcinoma cell lines PC-3, LNCaP and DU-145. In vive, gossypol appeared to inhibit tumor growth of subcutaneously implanted MAT-LyLu cells in Copenhagen rats. Gossypol may be an active agent for the treatment of hormone refractory metastatic prostate cancer.     

In vivo and in vitro effect of baicalein on human prostate cancer cells

We investigated the in vitro effects of baicalein and baicalin on human umbilical vein endothelial cells (HUVECs) and on human prostate tumor cells (DU-145 and PC3) as well as the effect of orally administered baicalein on the growth of DU-145 cells after subcutaneous injection into SCID mice. In vitro effects of baicalein and baicalin treatment on human prostate cancer cell lines DU-145 and PC-3 were assessed by employing cell proliferation (MTS) assay, cytotoxicity (LIVE/DEAD) assay, and TUNEL assay. In vitro anti-proliferative and anti-angiogenic properties of baicalein and baicalin were studied on HUVECs by sprout assay. The effect of orally administered baicalein on tumor growth in SCID mice was studied in four groups (n=10) of animals injected subcutaneously with DU-145 cells and treated daily for 28 days. The control group received only vehicle (carboxymethylcellulose), whereas the other three groups received escalating doses of baicalein (10, 20, and 40 mg/kg per day). Baicalein and baicalin exhibit dose-dependent growth inhibitory effects on human prostate cancer cells and umbilical vein endothelial cells in vitro. Also, treatment by these two flavonoid compounds significantly decreased the average number and length of sprouts formed by the endothelial cell aggregates in a dose-dependent manner. In vivo, treatment of mice with baicalein demonstrated a statistically significant tumor volume reduction (p<0.01) when compared to the control. This is the first study demonstrating an in vivo growth inhibitory effect of orally administered baicalein on human prostate tumors in mice.     

Connexin 26 induces growth suppression, apoptosis and increased efficacy of doxorubicin in prostate cancer cells

Connexin 26 (Cx26) encodes a gap junction protein and is a putative tumor suppressor gene. We evaluated the effect of forced expression of Cx26 on three human prostate cancer cell lines, PC-3, LNCap, and DU-145. The three cell lines were infected with a Cx26 adenovirus vector (Ad-Cx26) or a control vector or were mock infected. We tested cell growth, cell cycle, apoptosis, and the efficacy of combined treatment with doxorubicin. Ad-Cx26 infection suppressed the growth of all the cell lines compared with controls and induced cell cycle arrest at the G2/M phase and apoptosis. Ad-Cx26 decreased the expression of Bcl-2. LNCaP cell growth was dramatically suppressed by Ad-Cx26 alone. PC-3 and DU-145 had greater growth suppression with combined gene therapy and chemotherapy than with either Ad-Cx26 or doxorubicin alone. Forced expression of Cx26 suppresses the growth of prostate cancer cells and decreases the expression of Bcl-2. Combining Cx26 gene therapy with doxorubicin results in greater growth suppression.     

Cellular repair of oxidatively induced DNA base lesions is defective in prostate cancer cell lines, PC-3 and DU-145

Mutagenic oxidative DNA base damage increases with age in prostatic tissue. Various factors may influence this increase including: increased production of reactive oxygen species, increased susceptibility to oxidative stress, alterations in detoxifying enzyme levels or defects in DNA repair. Using liquid chromatography/mass spectrometry and gas chromatography/mass spectrometry, we show increased levels of oxidative DNA base lesions, 8-hydroxyguanine (8-oxoG), 8-hydroxyadenine (8-oxoA) and 5-hydroxycytosine (5OHC) over the baseline in PC-3 and DU-145 prostate cancer cells following exposure to ionizing radiation and a repair period. Nuclear extracts from PC-3 and DU-145 prostate cancer cell lines are defective in the incision of 8-oxoG, 5OHC and thymine glycol (TG) relative to the non-malignant prostate cell line. Consistent with reduced expression of OGG1 2a, incision of 8-oxoG is reduced in PC-3 and DU-145 mitochondrial extracts. We also show a correlation between severely defective incision of TG and 5OHC and reduced levels of NTH1 in PC-3 mitochondria. The antioxidant enzymes, glutathione peroxidase (GPx), catalase and superoxide dismutases (SOD1, SOD2), have altered expression patterns in these cancer cell lines. Genetic analysis of the OGG1 gene reveals that both PC-3 and DU-145 cell lines harbor polymorphisms associated with a higher susceptibility to certain cancers. These data suggest that the malignant phenotype in PC-3 and DU-145 cell lines may be associated with defects in base excision repair and alterations in expression of antioxidant enzymes.     

Bombesin stimulates nuclear factor kappa B activation and expression of proangiogenic factors in prostate cancer cells

The majority of deaths from prostate cancer occur in patients with androgen-insensitive metastatic disease. An important early event in the development of the metastatic phenotype is the induction of genes that promote angiogenesis, such as vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8), which are released from tumor cells into their microenvironment. Coincident with progression from prostatic carcinoma in situ to metastatic disease is an increase in the number of tumor cells exhibiting neuroendocrine (NE) differentiation. NE cells express a variety of peptide hormones, including the bombesin (BBS)-like peptide, gastrin-releasing peptide (GRP), and its cognate receptor, GRP-R. Although there is a strong positive correlation between the degree of NE differentiation and the metastatic potential of prostate cancers, a mechanistic link between increased expression of peptide hormone receptors, such as GRP-R, and proangiogenic gene expression has not been established. Here we report that BBS stimulates nuclear factor kappa B (NF kappa B) activation and proangiogenic gene expression in the androgen-insensitive prostate cancer cells lines, PC-3 and DU-145. In PC-3 cells, BBS stimulation of GRP-R resulted in the up-regulation of IL-8 and VEGF expression through a NF kappa B-dependent pathway. We show that BBS treatment induced inhibitor of NF kappa B degradation, NF kappa B translocation to the cell nucleus, increased NF kappa B binding to its DNA consensus sequence, and increased IL-8 and VEGF mRNA expression and protein secretion. Treatment with the proteasome inhibitor, MG-132, blocked BBS-stimulated NF kappa B DNA binding, and IL-8 and VEGF expression and secretion. Finally, media collected from PC-3 cell cultures, after BBS treatment, stimulated an NF kappa B-dependent migration of human umbilical vascular endothelial cells in vitro. Together, our data demonstrate a role for BBS and GRP-R in the NF kappa B-dependent up-regulation of proangiogenic gene expression, and suggest a possible molecular mechanism linking NE differentiation and the increased metastatic potential of androgen-insensitive prostate cancers.     

Effect of chromogranin A (pancreastatin) fragment on invasion of prostate cancer cells

We investigated the effect of chromogranin A (pancreastatin) fragment on the invasion of PC-3, DU-145 and LNCaP prostate cancer cells through a reconstituted basement membrane (Matrigel) using a Transwell cell culture chamber assay. Chromogranin A fragment increased the invasive capacity of both PC-3 and DU- 145 cells, whereas it had no significant effect of LNCaP cells. Chromogranin A fragment also increased the haptotactic migration of both PC-3 and DU-145 cells to fibronectin. Furthermore chromogranin A fragment increased the fibrinolytic activities of urokinase-type plasminogen activator (u-PA) in fibrin zymograms of both PC-3 and DU-145 cells and the expression of u-PA mRNA of PC-3 cells. However, the growth of these tumor cells was not affected by chromogranin A fragment at any concentrations used in this study. These results indicate that chromogranin A fragment increased the invasive potential of both PC-3 and DU-145 cells probably through enhancement of cell motility and the production of u-PA.     

Down-regulation of urokinase plasminogen activator and matrix metalloproteinases and up-regulation of their inhibitors by a novel nutrient mixture in human prostate cancer cell lines PC-3 and DU-145

Strong clinical and experimental evidence shows that elevated levels of urokinase plasminogen activators (u-PA) and matrix metalloproteinases (MMPs) are associated with prostate cancer progression, metastasis and shortened survival in patients. MMP activities are regulated by specific tissue inhibitors of metalloproteinases (TIMPs). A nutrient mixture (NM) containing lysine, proline, ascorbic acid and green tea extract showed anticancer activity against a number of cancer cell lines. Our main objective was to study the effect of NM on the activity of u-PA, MMPs and their inhibitor TIMPs on human prostate cancer cell lines PC-3 and DU-145. Human prostate cancer cell lines PC-3 and DU-145 (ATCC) were grown in MEM media with 10% FBS and antibiotics in 24?well tissue culture plates. At near confluence, the cells were treated with NM at 0-1000?μg/ml in triplicate at each concentration. Analysis of u-PA activity was carried out by fibrin zymography, MMPs by gelatinase zymography and TIMPs by reverse zymography. Both PC-3 and DU-145 prostate cancer cell lines demonstrated u-PA activity (subunits 1 and 2, corresponding to 35 and 33?kDa). Prostate cancer cell line PC-3 secretion of u-PA subunit 1 was decreased by 65% at NM 500?μg/ml and subunit 2 by 100% at NM 50?μg/ml. Prostate cancer cell line DU-145 secretion of u-PA subunit 1 was decreased by 97% at NM 500?μg/ml and subunit 2 by 100% at NM 100?μg/ml. Untreated PC-3 showed two bands for MMP-2 and MMP-9. NM inhibited their expression in a dose-dependent manner. The activity of MMP-2 and MMP-9 was significantly inhibited at 250?μg/ml with total inhibition at 500?μg/ml. DU-145 cells did not exhibit MMP activity. Activity of TIMPs was up-regulated in both prostate cancer cell lines in a dose-dependent manner. Minimum activity was expressed at 50?μg/ml NM and maximum at 1000?μg/ml. Correlation analyses revealed a positive correlation between u-PA and MMPs and a negative correlation between u-PA/MMPs and TIMPs. These results suggest NM as a potential anticancer agent since it targets invasive parameters of prostate cancer.     

miR-613通过下调Wnt/β-catenin信号通路活性抑制前列腺癌细胞的增殖与侵袭

目的:研究miR-613在人前列腺癌组织中的表达情况,探讨miR-613是否通过下调Wnt信号通路活性抑制前列腺癌细胞系细胞的增殖和侵袭能力。方法:收集临床前列腺癌组织及配对癌旁组织20例,通过实时荧光定量PCR(RT-qPCR)检测各组组织中miR-613的表达情况。进一步在细胞实验中,通过转染miR-613 mimic和miR-NC至离体培养的PC-3、DU-145细胞中,随后,采用MTT法、平板克隆实验检测细胞增殖和Matrigel侵袭实验测定前列腺癌细胞的侵袭情况,采用荧光素酶分析方法评估Wnt信号通路活性变化,采用实时荧光定量PCR(RT-qPCR)检测Wnt/β-catenin信号通路下游靶基因的转录(包括Cyclin D1和c-Myc),WB法检测细胞中β-catenin、c-Myc和Cyclin D1的表达量。结果:相比配对癌旁组织,miR-613在前列腺癌组织中的表达降低(P<0.01);在体外细胞实验中,相比于miR-NC组,转染miR-613 mimic后,PC-3、DU-145细胞增殖能力下降(P<0.05),PC-3、DU-145细胞的迁移侵袭能力下降(P<0.01);miR-613的过表达显著降低Wnt信号通路活性、β-catenin蛋白表达及Wnt信号下游靶基因Cyclin D1和c-Myc的转录及蛋白表达。结论:miR-613通过抑制Wnt/β-catenin信号通路来影响前列腺癌细胞的增殖与侵袭,为前列腺癌的潜在治疗靶点之一。