Manganese antagonizes iron blocking mitochondrial aconitase expression in human prostate carcinoma cells

Aim： To investigate the possible role of manganese in the regulation of mitochondrial aconitase （mACON） activity human prostate carcinoma cell line PC-3 cells. Methods： The mACON enzymatic activities of human prostate carcinoma cell line PC-3 cells were determined using a reduced nicotinamide adenine dinucleotide-coupled assay. Immunoblot and transient gene expression assays were used to study gene expression of the mACON. The putative response element for gene expression was identified using reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays. Results： In vitro study revealed that manganese chloride （MnCI2） treatment for 16 h inhibited the enzymatic activity of mACON, which induced the inhibition of citrate utility and cell proliferation of PC- 3 cells. Although results from transient gene expression assays showed that MnCI2 treatment upregulated gene translation by approximately 5-fold through the iron response element pathway, immunoblot and reporter assays showed that MnCl2 treatments inhibited protein and gene expression of mACON. This effect was reversed by cotreatment with ferric ammonium citrate. Additional reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays suggested that a putative metal response element in the promoter of the mACON gene was involved in the regulation of MnCh on the gene expression of mACON. Conclusion： These findings suggest that manganese acts as an antagonist of iron, disrupting the enzymatic activity and gene expression of mACON and citrate metabolism in the prostate.

Manganese antagonizes iron blocking mitochondrial aconitase expression in human prostate carcinoma cells

Aim:To investigate the possible role of manganese in the regulation of mitochondrial aconitase(mACON)activity human prostate carcinoma cell line PC-3 cells.Methods:The mACON enzymatic activities of human prostate carcinoma cell line PC-3 cells were determined using a reduced nicotinamide adenine dmucleotide-coupled assay. Immunoblot and transient gene expression assays were used to study gene expression of the mACON.The putative response element for gene expression was identified using reporter assays with site-directed mutagenesis and electro- phoretic mobility-shift assays.Results:In vitro study revealed that manganese chloride(MnCl2)treatment for 16h inhibited the enzymatic activity of mACON,which induced the inhibition of citrate utility and cell proliferation of PC- 3 cells.Although results from transient gene expression assays showed that MnCl_2,treatment upregulated gene translation by approximately 5-fold through the iron response element pathway,immunoblot and reporter assays showed that MnCl_2 treatments inhibited protein and gene expression of mACON.This effect was reversed by co- treatment with fenic ammonium citrate.Additional reporter assays with site-directed mutagenesis and electrophoretic mobility-shift assays suggested that a putative metal response element in the promoter of the mACON gene was involved in the regulation of MnCl_2 on the gene expression of mACON.Conclusion:These findings suggest that manganese acts as an antagonist of iron,disrupting the enzymatic activity and gene expression of mACON and citrate metabolism in the prostate.

Detection of androgen receptor (AR) and AR-V7 in small cell prostate carcinoma: Diagnostic and therapeutic implications

Objective:Small cell prostate carcinoma(SCPC)is a rare and highly malignant subtype of prostate cancer.SCPC frequently lacks androgen receptor(AR)and prostate-specific antigen(PSA)expression,and often responds poorly to androgen deprivation therapy(ADT).AR splice variant-7(AR-V7)is a truncated AR protein implicated in resistance to AR-targeting therapies.AR-V7 expression in castration-resistant prostate cancers has been evaluated extensively,and blood-based detection of AR-V7 has been associated with lack of response to abiraterone and enzalutamide.However,whether AR-V7 is expressed in SCPC is not known.Methods:Using validated antibodies,we performed immunohistochemistry(IHC)assay for the full-length AR(AR-FL)and(AR-V7)on post-ADT surgical SCPC specimens.Results:Seventy-five percent(9/12)of the specimens showed positive staining for the AR-FL with various intensities.Thirty-three percent(4/12)of the specimens showed positive staining for AR-V7.Among the specimens with positive AR-V7 staining,two samples displayed very weak staining,one sample showed weak-to-moderate staining,and one sample showed strong staining.All positive specimens displayed a heterogeneous pattern of AR-FL/AR-V7 staining.All specimens positive for AR-V7 were also positive for AR-FL.Conclusion:The study findings support the existence of measurable AR-FL and AR-V7 proteins in SCPC specimens.The results also have implications in detection of AR-V7 in specimens obtained through systemic sampling approaches such as circulating tumor cells.A positive AR-V7 finding by blood-based tests is not impossible in patients with SCPC who often demonstrate low PSA values.

Ectopic expression of neurotrophic peptide derived from saposin C increases proliferation and upregulates androgen receptor expression and transcriptional activity in human prostate cancer cells

Aim： To determine the effects of the functional domain of saposin C （neurotrophic peptide [NP]） on androgen receptor （AR） expression and transcriptional activity. Methods： We constructed DNA vectors expressing NP or a chimeric peptide of the viral TAT transduction domain and NP （TAT-NP） using gene cloning technology. The effects of ectopic expression of NP or TAT-NP on cell growth were examined by 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyl-2H-tetrazolium bromide （MTT） assay. Reverse transcription-polymerase chain reaction （RT-PCR）, Western blot, transient transfection and reporter gene assays were used to determine the effects of NP on AR expression and activation. Results： NP stimulated proliferation of androgen responsive LNCaP cells in the absence of androgens. RT-PCR and Western blot analyses showed that ectopic expression of NP resulted in induction of AR gene expression, and that the NP-stimulated expression of AR could be synergistically enhanced in the presence of androgens. Furthermore, reporter gene assay results showed that NP could enhance AR transactivation by increasing androgen-inducible gene reporter activity. Conclusion： We provided evidence that ectopic expression of saposin C-originated NP could upregulate AR gene expression and activate the AR transcriptional function in an androgen-independent manner in prostate cancer cells.

Inhibitory effects of apogossypolone on subcutaneous implants of human LNCaP prostatic carcinoma cells

Objective:The aim of this study was to investigate the inhibitory effect of apogossypolone (ApoG2) on subcutaneous implants of human LNCaP prostatic carcinoma cells, and explore its mechanism. Methods:To establish human LNCaP prostatic carcinoma cell line subcutaneous xenograft models and observe the inhibitory effect of ApoG2 on the tumor model. Immunohistochemistry was employed to observe the expression of Bcl-2, PCNA, CD31, caspase-3 and-8 in tumor tissues. The microvessel density was calculated. Results:ApoG2 could obviously inhibit the growth of subcutaneous prostatic carcinoma implant. ApoG2 decreased the expression of PCNA and CD31, and increased the expression of caspases-3,-8 in tumor tissues. Conclusion:ApoG2 has an inhibitory effect on prostatic carcinoma implants.

The effect of interleukin 6 on the growth of LNCaP and PC-3 prostatic carcinoma cells

Objective To investigate the effect of IL-6 on prostatic carcinoma cell lines, and differential effects on androgen-dependent and androgen-independent prostatic carcinoma cells. Methods The IL-6 producing capacities of LNCaP and PC-3 cells were determined, and effects of exogenous IL-6 and anti-IL - 6 antibodies on LNCaP and PC - 3 cells were examined. Results LNCaP produced a very small amount of IL-6, but PC-3 produced more, the concentraion of IL-6 being 190 pg/48 h per ml(1 × 106). The exogenous IL-6 inhibited LNCaP growth significantly,but had no obvious effect on PC -3 cells. Anti-IL-6 antibodies lowered PC-3 cells growth rate but had neutral effect on LNCaP. Conclusion PC-3 cells produces IL-6 massively in autocrine manner. IL-6 could be antagonized by anti-IL-6 antibodies,resulting in slowing PC-3 cells growth, and LNCaP cells growth could be inhibited by exogenous IL-6.7 refs,2 tabs.

Primary signet ring cell carcinoma of prostate (report of 2 cases)

Objective To study the clinical features of primary signet ring cell carcinoma of prostate. Methods 2 cases of primary signet ring cell carcinoma of the prostate were studied and reviewed. Results The age of the 2 patients was 64 and 73. The clinical symptoms were dysuria, vesical irritability and perineum discomfort. Histologically, signet ring cell carcinoma was composed of round cells with abundant clear cytoplasm and crescent-shaped nuclei on one side. Mitosis were frequently observed. Immunohistochemical testing showed the cancer cell was positive for prostate specific antigen (PSA.), prostate acid phosphatase ( PAP ), AR, cytokeratin and negative for caicinoernbryonic antigen (CEA), alcian blue/ periodic arid-schiff (AB/PAS). One case (stage D) died 6 months after bilateral orchiectomy and flutamide therapy because of wide-spead metastasis; the other (stage B2) has been surviving 25 months after radical prostatectomy, bilateral orchiectomy, endocrine therapy and local irradiation ministration.

Diagnosis and treatment of small cell carcinoma of prostate and a review of literature

Objective To investigate histological features, clinical presentation,treatment and prognosis of small cell carcinoma of prostate. Methods Clinical,pathological and follow-up data of two cases of small cell carcinoma of prostate were respectively analyzed,and trlated literature was reviewed. Results Two cases of small

Inhibitory effect of a new gossypol derivative apogossypolone (ApoG2) on xenograft of human prostate cancer cell line PC-3

Objective: To investigate the inhibitory effect of apogossypolone (ApoG2) on prostate cancer cell line PC-3 in vivo, and explore its mechanism. Methods: The models of transplantation tumors in Balb/c nu/nu mice were established via subcutaneous injection of PC-3 cells and the tumor-transplanted mice were divided into 4 groups: control group and three ApoG2 treatment groups, with 10 mice in each group. Volumes of the tumor were estimated every 2 d and the morphology of tumor tissues was observed. Immunohistochemistry was employed to observe the expression of Bcl-2, PCNA, CD31, caspase-3 and caspase-8 in tumor tissues. Results: ApoG2 (2.5 mg/kg-10 mg/kg) given intraperitoneally once a day can obviously inhibit the growth of subcutaneous prostatic carcinoma implant. The tumor volume decreased obviously when the treatment dosage was bigger than 5.0 mg/kg (P<0.01). Meanwhile, ApoG2 decreased the expression of PCNA and CD31, and enhanced the expression of caspases-3, caspase-8 in tumor tissues. Conclusion: ApoG2 exert an inhibitory effect on prostatic carcinoma possibly by inducing apoptosis and inhibiting tumor angiogenesis.

Immunohistochemical analysis of PD-L1 and tumor-infiltrating immune cells expression in the tumor microenvironment of primary signet ring cell carcinoma of the prostate

Primary signet ring cell carcinoma(SRCC)of the prostate is a rare neoplasm.However,its potential tumorigenic mechanism,clinicopathological features,and prognostic outcome have not been systematically described.To determine the pathogenic mechanism,we detected distributions of programmed cell death-ligand 1(PD-L1),programmed death 1(PD-1),and cellular components in the tumor microenvironment,including tumor-infiltrating lymphocytes(CD4 and CD8),tumor-associated macrophages(TAMs;CD163 and CD68),and tumor-associated fibroblasts(vimentin and alpha-smooth muscle actin[α-SMA]),in tumor tissues from four patients with primary prostatic SRCC compared with corresponding adjacent tissues and tumor tissues from 30 patients with prostate adenocarcinoma(PCa)by immunohistochemical staining.We found higher expression of PD-L1,CD163,and CD68 in primary SRCC specimens than that in both corresponding adjacent nontumor specimens and PCa specimens with different Gleason scores,indicating that TAMs may participate in the malignant biological behavior of primary SRCC of the prostate.For further analysis,we searched electronic journal databases and Surveillance,Epidemiology,and End Results(SEER)to identify 200 eligible patients including our four cases.According to Kaplan–Meier survival curve analysis,patients<68 years old,with radical prostatectomy(RP),Gleason score of 7–8,and lower clinical stage had longer overall survival(OS).Moreover,Cox multivariate analysis indicated that race(hazard ratio[HR]=1.422),surgical approach(HR=1.654),and Gleason score(HR=2.162)were independent prognostic factors for OS.Therefore,primary SRCC of the prostate represents a distinct and aggressive subtype of prostate cancer associated with a higher distribution of PD-L1 and TAMs,which warrants further clinical investigation.