Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 21
Filter
1.
Prostate ; 81(15): 1202-1213, 2021 11.
Article in English | MEDLINE | ID: mdl-34455614

ABSTRACT

BACKGROUND: Prostate cancer (PCa) is the most common visceral malignancy and the second leading cause of cancer deaths in US men. The two most common genetic alterations in PCa are expression of the TMPRSS2/ERG (TE) fusion gene and loss of the PTEN tumor suppressor. These genetic alterations act cooperatively to transform prostatic epithelium but the exact mechanisms involved are unclear. METHODS: Microarray expression analysis of immortalized prostate epithelial cells transformed by loss of PTEN and expression of the TE fusion revealed MEX3D as one of the most highly upregulated genes. MEX3D expression in prostate cancer was examined in patient samples and in silico. In vitro and in vivo studies to characterize the biological impact of MEX3D were carried out. Analysis of the TCGA PanCancer database revealed TCF3 as a major target of MEX3D. The induction of TCF3 by MEX3D was confirmed and the biological impact of TCF3 examined by in vitro studies. RESULTS: MEX3D is expressed at increased levels in prostate cancer and is increased by decreased PTEN and/or expression of the TE fusion gene and drives soft agar colony formation, invasion and tumor formation in vivo. The known oncogenic transcription factor TCF3 is highly correlated with MEX3D in prostate cancer. MEX3D expression strongly induces TCF3, which promotes soft agar colony formation and invasion in vitro. CONCLUSIONS: Loss of PTEN and expression of the TE fusion gene in prostate cancer strongly upregulates expression of MEX3D and its target TCF3 and promotes transformation associated phenotypes via this pathway.


Subject(s)
Carcinogenesis/genetics , Gene Expression Regulation, Neoplastic , Prostate/metabolism , Prostatic Neoplasms/metabolism , RNA-Binding Proteins/metabolism , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Carcinogenesis/pathology , Cell Line, Tumor , Humans , Male , Mice , PTEN Phosphohydrolase/genetics , PTEN Phosphohydrolase/metabolism , Prostate/pathology , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , RNA-Binding Proteins/genetics
2.
Prostate ; 80(1): 65-73, 2020 01.
Article in English | MEDLINE | ID: mdl-31614005

ABSTRACT

BACKGROUND: The TMPRSS2/ERG (TE) fusion gene is present in half of the prostate cancers (PCas). The TMPRSS2 and ERG junction of the fusion messenger RNA (mRNA) constitutes a cancer-specific target. Although docetaxel-based chemotherapy is the second line of therapy following development resistance to androgen ablation therapies, it is not curative. Therefore, the development of nontoxic novel monotherapies for targeting TE mRNA in PCa patients and for increasing the clinical efficacy of docetaxel treatment are needed. METHODS: We evaluated multiple approaches to enhance the delivery of TE small interfering RNA (siRNA) containing liposomes including PEGylation, topical treatment with nitroglycerin (NG) to increase permeability and retention, and three different PEG modifications: folate, RGD cyclic peptide, and a bFGF fibroblast growth factor receptor-targeting peptide. The efficacy of the optimized TE siRNA liposome in combination with docetaxel was then evaluated in vivo with or without topical NG in vivo using a VCaP xenograft model. TE fusion protein knockdown in residual tumors was assessed using Western blotting and immunohistochemistry. RESULTS: In vivo therapeutic targeting of TE fusion gene by systemic delivery of RGD-peptide-coated liposomal siRNA nanovectors led to sustained target silencing, suppressed tumor growth in xenograft models and enhanced the efficacy of docetaxel chemotherapy. Simultaneous application of the vasodilator NG to the skin further increased tissue the delivery of siRNA and enhanced target knockdown. CONCLUSION: TE-targeted gene silencing therapy using liposomal nanovectors is a potential therapeutic strategy as a monotherapy and to enhance the efficacy of chemotherapy in patients with advanced PCa.


Subject(s)
Docetaxel/pharmacology , Oncogene Proteins, Fusion/genetics , Prostatic Neoplasms, Castration-Resistant/therapy , RNA, Messenger/genetics , RNA, Small Interfering/administration & dosage , Animals , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Combined Modality Therapy , Gene Knockdown Techniques/methods , Humans , Liposomes/administration & dosage , Male , Mice , Molecular Targeted Therapy , Nanoparticles/administration & dosage , Prostatic Neoplasms, Castration-Resistant/drug therapy , Prostatic Neoplasms, Castration-Resistant/genetics , RNA, Small Interfering/genetics , Random Allocation , Transcriptional Regulator ERG/deficiency , Transcriptional Regulator ERG/genetics , Xenograft Model Antitumor Assays
3.
Open Med (Wars) ; 18(1): 20230700, 2023.
Article in English | MEDLINE | ID: mdl-37215053

ABSTRACT

Liver cancer is a prevalent malignant tumor with high mortality worldwide, making it urgent to explore new targets for liver cancer therapy. N-terminal EF-hand calcium binding protein 3 (NECAB3) is a new recognized regulator of cancer, while its role in liver cancer remained elusive. Thus, the study clarified the action of NECAB3 on liver cancer development and explored the detailed mechanism. We found that NECAB3 was enhanced in liver cancer. Knockdown of NECAB3 restrained liver cancer cell migration and invasion. Besides, knockdown of NECAB3 suppressed the activation of the hypoxia-inducible factor 1-alpha (HIF-1α)/Ras like without CAAX 1 (RIT1) pathway. Furthermore, NECAB3 regulated liver cancer migration and invasion through modulating RIT1 expression. Moreover, downregulation of NECAB3 suppressed liver cancer tumor growth in vivo. In conclusion, NECAB3 was upregulated in liver cancer. Knockdown of NECAB3 suppressed aggressive phenotype of liver cancer via modulating the HIF-1α/RIT1 axis, providing a possible target for liver cancer therapy.

4.
Kaohsiung J Med Sci ; 37(11): 991-999, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34370374

ABSTRACT

The aim of the study was to investigate the role of NSUN2 (NOP2/Sun RNA Methyltransferase Family Member 2) in hepatocellular carcinoma (HCC). The expressions of NSUN2 and FZR1 were measured. Cell viability, proliferation, and apoptosis were assessed. HCC xenograft in nude mouse model was established. Tumor weight and volume were examined. Tumor tissues were collected for immunohistochemistry (IHC). TCGA database analysis and clinical sample testing suggested that the transcript levels of NSUN2 and FZR1 were increased in HCC tissues. NSUN2 knockdown inhibited HCC cell viability and proliferation, and promoted cell apoptosis. Moreover, the effects of NSUN2 could be countered by overexpressing FZR1. In animal experiment, NSUN2 silencing suppressed tumor growth in nude mice by downregulating FZR1. In conclusion, NSUN2 has a regulatory effect on HCC cell proliferation and apoptosis. NSUN2 knockout could inhibit cellular processes in HCC and tumor growth, likely via FZR1 inhibition. This finding has not only revealed the role of NSUN2 in HCC growth, but also suggests a promising target for HCC treatment.


Subject(s)
Carcinoma, Hepatocellular/genetics , Cdh1 Proteins/genetics , Liver Neoplasms/genetics , Methyltransferases/genetics , Animals , Apoptosis/genetics , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Cdh1 Proteins/metabolism , Cell Line, Tumor , Cell Movement , Cell Proliferation , Gene Expression Regulation, Neoplastic , Humans , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Methyltransferases/antagonists & inhibitors , Methyltransferases/metabolism , Mice, Inbred BALB C , Mice, Nude , Neoplasm Invasiveness , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Signal Transduction , Tumor Burden , Xenograft Model Antitumor Assays
5.
Oncotarget ; 9(18): 14456-14471, 2018 Mar 06.
Article in English | MEDLINE | ID: mdl-29581856

ABSTRACT

Prostate cancer is the most common visceral malignancy and the second leading cause of cancer deaths in US men. Correlative studies in human prostate cancers reveal a frequent association of the TMPRSS2/ERG (TE) fusion gene with loss of PTEN and studies in mouse models reveal that ERG expression and PTEN loss synergistically promote prostate cancer progression. To determine the mechanism by which ERG overexpression and PTEN loss leads to transformation, we overexpressed the TE fusion gene and knocked down PTEN in an immortalized but non-transformed prostate epithelial cell line. We show that ERG overexpression in combination with PTEN loss can transform these immortalized but non-tumorigenic cells, while either alteration alone was not sufficient to fully transform these cells. Expression microarray analysis revealed extensive changes in gene expression in cells expressing the TE fusion with loss of PTEN. Among these gene expression changes was increased expression of multiple FGF ligands and receptors. We show that activation of fibroblast growth factor receptor signaling plays a key role in transformation induced by TE fusion gene expression in association with PTEN loss. In addition, in vitro and in silico analysis reveals PTEN loss is associated with widespread increases in FGF ligands and receptors in prostate cancer. Inhibitors of FGF receptor signaling are currently entering the clinic and our results suggests that FGF receptor signaling is a therapeutic target in cancers with TE fusion gene expression and PTEN loss.

6.
Clin Cancer Res ; 23(16): 4885-4896, 2017 Aug 15.
Article in English | MEDLINE | ID: mdl-28490466

ABSTRACT

Purpose: Large diameter perineural prostate cancer is associated with poor outcomes. GDNF, with its coreceptor GFRα1, binds RET and activates downstream pro-oncogenic signaling. Because both GDNF and GFRα1 are secreted by nerves, we examined the role of RET signaling in prostate cancer.Experimental Design: Expression of RET, GDNF, and/or GFRα1 was assessed. The impact of RET signaling on proliferation, invasion and soft agar colony formation, perineural invasion, and growth in vivo was determined. Cellular signaling downstream of RET was examined by Western blotting.Results: RET is expressed in all prostate cancer cell lines. GFRα1 is only expressed in 22Rv1 cells, which is the only line that responds to exogenous GDNF. In contrast, all cell lines respond to GDNF plus GFRα1. Conditioned medium from dorsal root ganglia contains secreted GFRα1 and promotes transformation-related phenotypes, which can be blocked by anti-GFRα1 antibody. Perineural invasion in the dorsal root ganglion assay is inhibited by anti-GFRα antibody and RET knockdown. In vivo, knockdown of RET inhibits tumor growth. RET signaling activates ERK or AKT signaling depending on context, but phosphorylation of p70S6 kinase is markedly increased in all cases. Knockdown of p70S6 kinase markedly decreases RET induced transformed phenotypes. Finally, RET is expressed in 18% of adenocarcinomas and all three small-cell carcinomas examined.Conclusions: RET promotes transformation associated phenotypes, including perineural invasion in prostate cancer via activation of p70S6 kinase. GFRα1, which is secreted by nerves, is a limiting factor for RET signaling, creating a perineural niche where RET signaling can occur. Clin Cancer Res; 23(16); 4885-96. ©2017 AACR.


Subject(s)
Gene Expression Regulation, Neoplastic , Prostatic Neoplasms/genetics , Proto-Oncogene Proteins c-ret/genetics , Signal Transduction/genetics , Animals , Cell Line , Cell Line, Tumor , HEK293 Cells , Humans , Male , Mice, Inbred C57BL , Mice, SCID , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/therapy , Proto-Oncogene Proteins c-ret/metabolism , RNA Interference , RNAi Therapeutics/methods , Tumor Burden/genetics , Xenograft Model Antitumor Assays
7.
Oncotarget ; 8(36): 60243-60256, 2017 Sep 01.
Article in English | MEDLINE | ID: mdl-28947967

ABSTRACT

Prostate cancer is one of the most frequently diagnosed neoplasms among men worldwide. MicroRNAs (miRNAs) are involved in numerous important cellular processes including proliferation, differentiation and apoptosis. They have been found to be aberrantly expressed in many types of human cancers. They can act as either tumor suppressors or oncogenes, and changes in their levels are associated with tumor initiation, progression and metastasis. miR-33a is an intronic miRNA embedded within SREBF2 that has been reported to have tumor suppressive properties in some cancers but has not been examined in prostate cancer. SREBF2 increases cholesterol and lipid levels both directly and via miR-33a action. The levels of SREBF2 and miR-33a are correlated in normal tissues by co-transcription from the same gene locus. Paradoxically, SREBF2 has been reported to be increased in prostate cancer, which would be predicted to increase miR-33a levels potentially leading to tumor suppression. We show here that miR-33a has tumor suppressive activities and is decreased in prostate cancer. The decreased miR-33a increases mRNA for the PIM1 oncogene and multiple genes in the lipid ß-oxidation pathway. Levels of miR-33a are not correlated with SREBF2 levels, implying posttranscriptional regulation of its expression in prostate cancer.

8.
Cancer Res ; 77(16): 4247-4257, 2017 08 15.
Article in English | MEDLINE | ID: mdl-28611045

ABSTRACT

African American (AA) men exhibit a relatively high incidence and mortality due to prostate cancer even after adjustment for socioeconomic factors, but the biological basis for this disparity is unclear. Here, we identify a novel region on chromosome 4p16.3 that is lost selectively in AA prostate cancer. The negative regulator of G-protein signaling RGS12 was defined as the target of 4p16.3 deletions, although it has not been implicated previously as a tumor-suppressor gene. RGS12 transcript levels were relatively reduced in AA prostate cancer, and prostate cancer cell lines showed decreased RGS12 expression relative to benign prostate epithelial cells. Notably, RGS12 exhibited potent tumor-suppressor activity in prostate cancer and prostate epithelial cell lines in vitro and in vivo We found that RGS12 expression correlated negatively with the oncogene MNX1 and regulated its expression in vitro and in vivo Further, MNX1 was regulated by AKT activity, and RGS12 expression decreased total and activated AKT levels. Our findings identify RGS12 as a candidate tumor-suppressor gene in AA prostate cancer, which acts by decreasing expression of AKT and MNX1, establishing a novel oncogenic axis in this disparate disease setting. Cancer Res; 77(16); 4247-57. ©2017 AACR.


Subject(s)
Black or African American/genetics , Genes, Tumor Suppressor , Homeodomain Proteins/biosynthesis , Oncogene Protein v-akt/biosynthesis , Prostatic Neoplasms/genetics , RGS Proteins/genetics , Transcription Factors/biosynthesis , Animals , Cell Line, Tumor , Cell Proliferation/genetics , Heterografts , Homeodomain Proteins/genetics , Humans , Male , Mice , Oncogene Protein v-akt/genetics , Prostatic Neoplasms/ethnology , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Transcription Factors/genetics , Transfection
9.
Oncotarget ; 8(4): 6179-6192, 2017 Jan 24.
Article in English | MEDLINE | ID: mdl-28008155

ABSTRACT

Activation of the PI3K/AKT pathway occurs in the vast majority of advanced prostate cancers (PCas). Activation of fibroblast growth factor receptor (FGFR) signaling occurs in a wide variety of malignancies, including PCa. RNA-Seq of castration resistant PCa revealed expression of multiple FGFR signaling components compatible with FGFR signaling in all cases, with multiple FGF ligands expressed in 90% of cases. Immunohistochemistry confirmed FGFR signaling in the majority of xenografts and advanced PCas. AZD5363, an AKT kinase inhibitor and AZD4547, a FGFR kinase inhibitor are under active clinical development. We therefore sought to determine if these two drugs have additive effects in PCa models. The effect of both agents, singly and in combination was evaluated in a variety of PCa cell lines in vitro and in vivo. All cell lines tested responded to both drugs with decreased invasion, soft agar colony formation and growth in vivo, with additive effects seen with combination treatment. Activation of the FGFR, AKT, ERK and STAT3 pathways was examined in treated cells. AZD5363 inhibited AKT signaling and increased FGFR1 signaling, which partially compensated for decreased AKT kinase activity. While AZD4547 could effectively block the ERK pathway, combination treatment was needed to completely block STAT3 activation. Thus combination treatment with AKT and FGFR kinase inhibitors have additive effects on malignant phenotypes in vitro and in vivo by inhibiting multiple signaling pathways and mitigating the compensatory upregulation of FGFR signaling induced by AKT kinase inhibition. Our studies suggest that co-targeting these pathways may be efficacious in advanced PCa.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Benzamides/pharmacology , Piperazines/pharmacology , Prostatic Neoplasms/drug therapy , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Pyrroles/pharmacology , Receptor, Fibroblast Growth Factor, Type 1/antagonists & inhibitors , Animals , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Extracellular Signal-Regulated MAP Kinases/metabolism , Humans , Male , Mice, SCID , Phosphorylation , Prostatic Neoplasms/enzymology , Prostatic Neoplasms/pathology , Proto-Oncogene Proteins c-akt/metabolism , Receptor, Fibroblast Growth Factor, Type 1/metabolism , STAT3 Transcription Factor/metabolism , Signal Transduction/drug effects , Tumor Burden/drug effects , Xenograft Model Antitumor Assays
10.
Cancer Res ; 76(21): 6290-6298, 2016 11 01.
Article in English | MEDLINE | ID: mdl-27578002

ABSTRACT

Incidence and mortality rates for prostate cancer are higher in African-American (AA) men than in European-American (EA) men, but the biologic basis for this disparity is unclear. We carried out a detailed analysis of gene expression changes in prostate cancer compared with their matched benign tissues in a cohort of AA men and compared them with existing data from EA men. In this manner, we identified MNX1 as a novel oncogene upregulated to a relatively greater degree in prostate cancer from AA men. Androgen and AKT signaling play a central role in the pathogenesis of prostate cancer and we found that both of these signaling pathways increased MNX1 expression. MNX1 in turn upregulated lipid synthesis by stimulating expression of SREBP1 and fatty acid synthetase. Our results define MNX1 as a novel targetable oncogene increased in AA prostate cancer that is associated with aggressive disease. Cancer Res; 76(21); 6290-8. ©2016 AACR.


Subject(s)
Gene Expression Regulation, Neoplastic , Homeodomain Proteins/genetics , Oncogenes , Prostatic Neoplasms/genetics , Transcription Factors/genetics , Black or African American , Animals , Cell Line, Tumor , Humans , Male , Mice , Prostatic Neoplasms/ethnology , Proto-Oncogene Proteins c-akt/physiology , Receptors, Androgen/physiology , Sterol Regulatory Element Binding Protein 1/genetics
11.
Oncotarget ; 6(8): 6281-94, 2015 Mar 20.
Article in English | MEDLINE | ID: mdl-25749044

ABSTRACT

Majority of prostate cancer (PCa) patients carry TMPRSS2/ERG (T/E) fusion genes and there has been tremendous interest in understanding how the T/E fusion may promote progression of PCa. We showed that T/E fusion can activate NF-kB pathway by increasing phosphorylation of NF-kB p65 Ser536 (p536), but the function of p536 has never been studied in PCa. We report here that active p536 can significantly increase cell motility and transform PNT1a cells (an immortalized normal cell line), suggesting p536 plays a critical role in promoting PCa tumorigenesis. We have discovered a set of p536 regulated genes, among which we validated the regulation of CCL2 by p536. Based on all evidence, we favor that T/E fusion, NF-kB p536 and CCL2 form a signaling chain. Finally, PNT1a cells (not tumorigenic) can form tumors in SCID mice when overexpressing of either wild type or active p65 in the presence of activated AKT, demonstrating synergistic activities of NF-kB and AKT signals in promoting PCa tumorigenesis. These findings indicate that combination therapies targeting T/E fusion, NF-kB, CCL2 and/or AKT pathways may have efficacy in T/E fusion gene expressing PCa. If successful, such targeted therapy will benefit more than half of PCa patients who carry T/E fusions.


Subject(s)
Prostatic Neoplasms/metabolism , Transcription Factor RelA/metabolism , Animals , Carcinogenesis/genetics , Carcinogenesis/metabolism , Cell Line, Tumor , Gene Fusion , HEK293 Cells , Heterografts , Humans , Male , Mice , Mice, SCID , Phosphorylation , Prostatic Neoplasms/genetics , Serine Endopeptidases/genetics , Signal Transduction , Trans-Activators/genetics , Transcriptional Regulator ERG , Transfection
12.
Endocrinology ; 144(1): 313-25, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12488360

ABSTRACT

In the mouse, there is a large family of paralogous genes closely related to PRL. The objective of this report was to investigate the organization of the mouse PRL gene family locus. PRL family genes reside on chromosome 13 of the mouse genome. The PRL gene family members were localized to a series of overlapping bacterial artificial chromosome clones and arranged based on structural relationships. Additionally, several new members of the PRL gene family were identified. Placental lactogen I (PL-I) was found to be encoded by three closely related (>98% exon sequence identity) contiguous genes (termed: PL-Ialpha, PL-Ibeta, and PL-Igamma). Two previously unidentified mouse orthologs for members of the rat PRL family, PRL-like protein-I (PLP-I) and PLP-K were discovered, as were two new members of the PLP-C subfamily, PLP-Cgamma and PLP-Cdelta, and two new entirely unique members of the PRL family, PLP-N and PLP-O. Amino acid sequences predicted from the latter two genes most closely resembled proliferin-related protein. Each of the nine newly discovered genes is expressed in trophoblast cells of the mouse placenta in a gestationally specific pattern. In summary, elucidation of the mouse PRL gene family locus provides new insights into the expansion of the mouse PRL family and new tools for studying the genetics and biology of its members.


Subject(s)
Prolactin/genetics , Amino Acid Sequence , Animals , Chromosome Mapping , Female , Gene Expression , Gonadotropins/chemistry , Gonadotropins/genetics , Mice , Molecular Sequence Data , Placenta/metabolism , Placental Lactogen/chemistry , Placental Lactogen/genetics , Pregnancy , Pregnancy Proteins/chemistry , Pregnancy Proteins/genetics , Prolactin/chemistry , Rats , Sequence Homology , Trophoblasts/metabolism
13.
Sci China C Life Sci ; 45(4): 379-87, 2002 Aug.
Article in English | MEDLINE | ID: mdl-18759025

ABSTRACT

The expressions of vascular endothelial growth factor (VEGF) in rat ovarian follicles and corpus luteum (CL) during different stages of pregnancy and postpartum were investigated. In addition, the effect of tumor necrosis factor-alpha (TNF-alpha) on VEGF expression was examined. VEGF mRNA was localized in granulosa cells of preantral follicles, as well as in the granulosa and theca cells of small antral follicles, but not in large antral follicles. VEGF transcripts were amplified in rat CL during pregnancy and postpartum using RT-PCR. The mRNA expression reached the maximal level on day 7, maintained it on days 9-18, decreased after day 18, and was minimal on day 1 postpartum. Western blot showed a 23 ku VEGF protein band in rat CL. Expression of VEGF protein varied in a similar way to that of its mRNA. Treatment with TNF-alpha at a dosage of 3000 IU/kg on day 4 of pregnancy significantly increased VEGF expression in rat CL. It is suggested that the down-regulation of VEGF expression in large antral follicles may be one factor that contributes to the termination of ovulation in rat ovary during pregnancy. VEGF may be implicated in the CL formation and maintenance via regulating angiogenesis, and its expression is regulated by TNF-alpha.

14.
Endocrinology ; 155(9): 3262-73, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24926821

ABSTRACT

A number of preclinical studies have shown that the activation of the vitamin D receptor (VDR) reduces prostate cancer (PCa) cell and tumor growth. The majority of human PCas express a transmembrane protease serine 2 (TMPRSS2):erythroblast transformation-specific (ETS) fusion gene, but most preclinical studies have been performed in PCa models lacking TMPRSS2:ETS in part due to the limited availability of model systems expressing endogenous TMPRSS2:ETS. The level of the active metabolite of vitamin D, 1α,25-dihydroxyvitamin D3 (1,25D), is controlled in part by VDR-dependent induction of cytochrome P450, family 24, subfamily 1, polypeptide1 (CYP24A1), which metabolizes 1,25D to an inactive form. Because ETS factors can cooperate with VDR to induce rat CYP24A1, we tested whether TMPRSS2:ETS would cause aberrant induction of human CYP24A1 limiting the activity of VDR. In TMPRSS2:ETS positive VCaP cells, depletion of TMPRSS2:ETS substantially reduced 1,25D-mediated CYP24A1 induction. Artificial expression of the type VI+72 TMPRSS2:ETS isoform in LNCaP cells synergized with 1,25D to greatly increase CYP24A1 expression. Thus, one of the early effects of TMPRSS2:ETS in prostate cells is likely a reduction in intracellular 1,25D, which may lead to increased proliferation. Next, we tested the net effect of VDR action in TMPRSS2:ETS containing PCa tumors in vivo. Unlike previous animal studies performed on PCa tumors lacking TMPRSS2:ETS, EB1089 (seocalcitol) (a less calcemic analog of 1,25D) did not inhibit the growth of TMPRSS2:ETS containing VCaP tumors in vivo, suggesting that the presence of TMPRSS2:ETS may limit the growth inhibitory actions of VDR. Our findings suggest that patients with TMPRSS2:ETS negative tumors may be more responsive to VDR-mediated growth inhibition and that TMPRSS2:ETS status should be considered in future clinical trials.


Subject(s)
Gene Fusion , Prostatic Neoplasms/genetics , Prostatic Neoplasms/metabolism , Serine Endopeptidases/genetics , Steroid Hydroxylases/metabolism , Trans-Activators/genetics , Vitamin D/analogs & derivatives , Animals , Cell Line, Tumor , Humans , Male , Mice , Prostatic Neoplasms/enzymology , Receptors, Calcitriol/genetics , Serine Endopeptidases/metabolism , Signal Transduction , Steroid Hydroxylases/genetics , Trans-Activators/metabolism , Transcriptional Regulator ERG , Up-Regulation , Vitamin D/genetics , Vitamin D/metabolism , Vitamin D3 24-Hydroxylase
15.
PLoS One ; 8(3): e58391, 2013.
Article in English | MEDLINE | ID: mdl-23554889

ABSTRACT

The TMPRSS2/ERG (T/E) fusion gene is present in the majority of all prostate cancers (PCa). We have shown previously that NF-kB signaling is highly activated in these T/E fusion expressing cells via phosphorylation of NF-kB p65 Ser536 (p536). We therefore hypothesize that targeting NF-kB signaling may be an efficacious approach for the subgroup of PCas that carry T/E fusions. Celastrol is a well known NF-kB inhibitor, and thus may inhibit T/E fusion expressing PCa cell growth. We therefore evaluated Celastrol's effects in vitro and in vivo in VCaP cells, which express the T/E fusion gene. VCaP cells were treated with different concentrations of Celastrol and growth inhibition and target expression were evaluated. To test its ability to inhibit growth in vivo, 0.5 mg/kg Celastrol was used to treat mice bearing subcutaneous VCaP xenograft tumors. Our results show Celastrol can significantly inhibit the growth of T/E fusion expressing PCa cells both in vitro and in vivo through targeting three critical signaling pathways: AR, ERG and NF-kB in these cells. When mice received 0.5 mg/kg Celastrol for 4 times/week, significant growth inhibition was seen with no obvious toxicity or significant weight loss. Therefore, Celastrol is a promising candidate drug for T/E fusion expressing PCa. Our findings provide a novel strategy for the targeted therapy which may benefit the more than half of PCa patients who have T/E fusion expressing PCas.


Subject(s)
Antineoplastic Agents/pharmacology , Gene Expression Regulation, Neoplastic/drug effects , Oncogene Proteins, Fusion/biosynthesis , Prostatic Neoplasms , Receptors, Androgen/metabolism , Signal Transduction/drug effects , Trans-Activators/metabolism , Transcription Factor RelA/metabolism , Triterpenes/pharmacology , Animals , Cell Line, Tumor , Dose-Response Relationship, Drug , Humans , Male , Mice , Mice, Nude , Pentacyclic Triterpenes , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Transcriptional Regulator ERG
16.
Clin Cancer Res ; 18(14): 3880-8, 2012 Jul 15.
Article in English | MEDLINE | ID: mdl-22573348

ABSTRACT

PURPOSE: Extensive correlative studies in human prostate cancer as well as studies in vitro and in mouse models indicate that fibroblast growth factor receptor (FGFR) signaling plays an important role in prostate cancer progression. In this study, we used a probe compound for an FGFR inhibitor, which potently inhibits FGFR-1-3 and significantly inhibits FGFR-4. The purpose of this study is to determine whether targeting FGFR signaling from all four FGFRs will have in vitro activities consistent with inhibition of tumor progression and will inhibit tumor progression in vivo. EXPERIMENTAL DESIGN: Effects of AZ8010 on FGFR signaling and invasion were analyzed using immortalized normal prostate epithelial (PNT1a) cells and PNT1a overexpressing FGFR-1 or FGFR-4. The effect of AZ8010 on invasion and proliferation in vitro was also evaluated in prostate cancer cell lines. Finally, the impact of AZ8010 on tumor progression in vivo was evaluated using a VCaP xenograft model. RESULTS: AZ8010 completely inhibits FGFR-1 and significantly inhibits FGFR-4 signaling at 100 nmol/L, which is an achievable in vivo concentration. This results in marked inhibition of extracellular signal-regulated kinase (ERK) phosphorylation and invasion in PNT1a cells expressing FGFR-1 and FGFR-4 and all prostate cancer cell lines tested. Treatment in vivo completely inhibited VCaP tumor growth and significantly inhibited angiogenesis and proliferation and increased cell death in treated tumors. This was associated with marked inhibition of ERK phosphorylation in treated tumors. CONCLUSIONS: Targeting FGFR signaling is a promising new approach to treating aggressive prostate cancer.


Subject(s)
Prostatic Neoplasms , Receptor, Fibroblast Growth Factor, Type 1 , Receptor, Fibroblast Growth Factor, Type 4 , Animals , Apoptosis/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Extracellular Signal-Regulated MAP Kinases/genetics , Extracellular Signal-Regulated MAP Kinases/metabolism , Gene Expression Regulation, Neoplastic/drug effects , Humans , Male , Mice , Molecular Targeted Therapy , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/genetics , Neovascularization, Pathologic , Prostate/cytology , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Receptor, Fibroblast Growth Factor, Type 1/antagonists & inhibitors , Receptor, Fibroblast Growth Factor, Type 1/genetics , Receptor, Fibroblast Growth Factor, Type 1/metabolism , Receptor, Fibroblast Growth Factor, Type 4/antagonists & inhibitors , Receptor, Fibroblast Growth Factor, Type 4/genetics , Receptor, Fibroblast Growth Factor, Type 4/metabolism , Signal Transduction
17.
Clin Cancer Res ; 18(24): 6648-57, 2012 Dec 15.
Article in English | MEDLINE | ID: mdl-23052253

ABSTRACT

PURPOSE: The TMPRSS2/ERG (T/E) fusion gene is present in half of all prostate cancer tumors. Fusion of the oncogenic ERG gene with the androgen-regulated TMPRSS2 gene promoter results in expression of fusion mRNAs in prostate cancer cells. The junction of theTMPRSS2- and ERG-derived portions of the fusion mRNA constitutes a cancer-specific target in cells containing the T/E fusion gene. Targeting the most common alternatively spliced fusion gene mRNA junctional isoforms in vivo using siRNAs in liposomal nanovectors may potentially be a novel, low-toxicity treatment for prostate cancer. EXPERIMENTAL DESIGN: We designed and optimized siRNAs targeting the two most common T/E fusion gene mRNA junctional isoforms (type III or type VI). Specificity of siRNAs was assessed by transient co-transfection in vitro. To test their ability to inhibit growth of prostate cancer cells expressing these fusion gene isoforms in vivo, specific siRNAs in liposomal nanovectors were used to treat mice bearing orthotopic or subcutaneous xenograft tumors expressing the targeted fusion isoforms. RESULTS: The targeting siRNAs were both potent and highly specific in vitro. In vivo they significantly inhibited tumor growth. The degree of growth inhibition was variable and was correlated with the extent of fusion gene knockdown. The growth inhibition was associated with marked inhibition of angiogenesis and, to a lesser degree, proliferation and a marked increase in apoptosis of tumor cells. No toxicity was observed. CONCLUSIONS: Targeting the T/E fusion junction in vivo with specific siRNAs delivered via liposomal nanovectors is a promising therapy for men with prostate cancer.


Subject(s)
Oncogene Proteins, Fusion/genetics , RNA Interference , RNA, Small Interfering/genetics , Transfection/methods , Animals , Cell Line, Tumor , Gene Knockdown Techniques , Humans , Liposomes , Male , Mice , Mice, Nude , Neoplasm Transplantation , Oncogene Proteins, Fusion/metabolism , Prostatic Neoplasms/therapy , Protein Isoforms/genetics , Protein Isoforms/metabolism , Trans-Activators/genetics , Trans-Activators/metabolism , Transcriptional Regulator ERG
18.
Cancer Res ; 71(4): 1325-33, 2011 Feb 15.
Article in English | MEDLINE | ID: mdl-21169414

ABSTRACT

The TMPRSS2/ERG (T/E) fusion gene is present and thought to be an oncogenic driver of approximately half of all prostate cancers. Fusion of the androgen-regulated TMPRSS2 promoter to the ERG oncogene results in constitutive high level expression of ERG which promotes prostate cancer invasion and proliferation. Here, we report the characterization of multiple alternatively spliced T/E fusion gene isoforms which have differential effects on invasion and proliferation. We found that T/E fusion gene isoforms differentially increase NF-κB-mediated transcription, which may explain in part the differences in biological activities of the T/E fusion isoforms. This increased activity is due to phosphorylation of NF-κB p65 on Ser536. Tissue microarray immunochemistry revealed that p65 phospho-Ser536 is present in the majority of prostate cancers where it is associated with ERG protein expression. The T/E fusion gene isoforms differentially increase expression of a number of NF-κB associated genes including PAR1, CCL2, FOS, TLR3, and TLR4 (Toll-like receptor). TLR4 activation is known to promote p65 Ser536 phosphorylation and knockdown of TLR4 with shRNA decreases Ser536 phosphorylation in T/E fusion gene expressing cells. TLR4 can be activated by proteins in the tumor microenvironment and lipopolysacharide from Gram (-) bacteria. Our findings suggest that bacterial infection of the prostate and/or endogenous microenvironment proteins may promote progression of high-grade prostatic intraepithelial neoplasia and/or prostate cancers that express the T/E fusion gene, where the NF-κB pathway might be targeted as a rational therapeutic approach.


Subject(s)
NF-kappa B/metabolism , Oncogene Proteins, Fusion/physiology , Toll-Like Receptor 4/physiology , Animals , COS Cells , Cell Proliferation/drug effects , Cells, Cultured , Chlorocebus aethiops , Gene Knockdown Techniques , Humans , Male , NF-kappa B/agonists , Oncogene Proteins, Fusion/chemistry , Oncogene Proteins, Fusion/pharmacology , Prostatic Intraepithelial Neoplasia/genetics , Prostatic Intraepithelial Neoplasia/metabolism , Prostatic Intraepithelial Neoplasia/pathology , Prostatic Neoplasms/genetics , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Protein Isoforms/chemistry , Protein Isoforms/pharmacology , Protein Isoforms/physiology , RNA, Small Interfering/pharmacology , Toll-Like Receptor 4/antagonists & inhibitors , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Tumor Microenvironment/drug effects , Tumor Microenvironment/genetics , Tumor Microenvironment/physiology
19.
Cancer Res ; 71(2): 572-82, 2011 Jan 15.
Article in English | MEDLINE | ID: mdl-21224358

ABSTRACT

Patients with metastatic prostate cancer who undergo androgen-ablation therapy invariably relapse and develop incurable castration-resistant disease. Activation of the prosurvival Akt pathway accompanies androgen ablation. We discovered that the androgen receptor induces the expression of the tumor suppressor inositol polyphosphate 4-phosphatase type II (INPP4B) but not PTEN in prostate cancer cells. Optimal induction of INPP4B by an androgen receptor required the expression of the transcriptional coactivator NCoR. INPP4B dephosphorylates phosphatidylinositol-3, 4-bisphosphate, which leads to reduced phosphorylation and activity of Akt. In support of a key role for INPP4B in Akt control, INPP4B depletion activated Akt and increased cellular proliferation. The clinical significance of INPP4B in androgen-dependent prostate cancers was determined in normal or primary tumor prostate tissues derived from radical prostatectomy specimens. In primary tumors, the expression of both INPP4B and PTEN was substantially reduced compared with normal tissue. Further, the decreased expression of INPP4B reduced the time to biochemical recurrence. Thus, androgen ablation can activate the Akt pathway via INPP4B downregulation, thereby mitigating the antitumor effects of androgen ablation. Our findings reinforce the concept that patients undergoing androgen ablation may benefit from Akt-targeting therapies.


Subject(s)
Androgens/pharmacology , Genes, Tumor Suppressor , Phosphoric Monoester Hydrolases/genetics , Prostatic Neoplasms/enzymology , Prostatic Neoplasms/genetics , Androgens/metabolism , Cell Growth Processes/physiology , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Humans , Male , Neoplasm Recurrence, Local/enzymology , Neoplasm Recurrence, Local/metabolism , PTEN Phosphohydrolase/biosynthesis , PTEN Phosphohydrolase/genetics , PTEN Phosphohydrolase/metabolism , Phosphoric Monoester Hydrolases/biosynthesis , Phosphoric Monoester Hydrolases/deficiency , Prostatic Neoplasms/pathology , Proto-Oncogene Proteins c-akt/metabolism , Receptors, Androgen/genetics , Transfection
20.
Aging Cell ; 10(6): 996-1010, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21895961

ABSTRACT

Aging is associated with increased adiposity in white adipose tissues and impaired thermogenesis in brown adipose tissues; both contribute to increased incidences of obesity and type 2 diabetes. Ghrelin is the only known circulating orexigenic hormone that promotes adiposity. In this study, we show that ablation of the ghrelin receptor (growth hormone secretagogue receptor, GHS-R) improves insulin sensitivity during aging. Compared to wild-type (WT) mice, old Ghsr(-/-) mice have reduced fat and preserve a healthier lipid profile. Old Ghsr(-/-) mice also exhibit elevated energy expenditure and resting metabolic rate, yet have similar food intake and locomotor activity. While GHS-R expression in white and brown adipose tissues was below the detectable level in the young mice, GHS-R expression was readily detectable in visceral white fat and interscapular brown fat of the old mice. Gene expression profiles reveal that Ghsr ablation reduced glucose/lipid uptake and lipogenesis in white adipose tissues but increased thermogenic capacity in brown adipose tissues. Ghsr ablation prevents age-associated decline in thermogenic gene expression of uncoupling protein 1 (UCP1). Cell culture studies in brown adipocytes further demonstrate that ghrelin suppresses the expression of adipogenic and thermogenic genes, while GHS-R antagonist abolishes ghrelin's effects and increases UCP1 expression. Hence, GHS-R plays an important role in thermogenic impairment during aging. Ghsr ablation improves aging-associated obesity and insulin resistance by reducing adiposity and increasing thermogenesis. Growth hormone secretagogue receptor antagonists may be a new means of combating obesity by shifting the energy balance from obesogenesis to thermogenesis.


Subject(s)
Adipose Tissue, Brown/metabolism , Adipose Tissue, White/metabolism , Aging/genetics , Diabetes Mellitus, Type 2/metabolism , Gene Expression Regulation , Obesity/metabolism , Receptors, Ghrelin/deficiency , Signal Transduction/genetics , Adiposity/genetics , Animals , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/prevention & control , Eating/physiology , Energy Metabolism/physiology , Ghrelin/genetics , Ghrelin/metabolism , Humans , Insulin Resistance/genetics , Ion Channels/genetics , Ion Channels/metabolism , Lipid Metabolism/genetics , Male , Mice , Mice, Knockout , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Obesity/complications , Obesity/genetics , Obesity/prevention & control , Receptors, Ghrelin/antagonists & inhibitors , Receptors, Ghrelin/genetics , Thermogenesis/physiology , Uncoupling Protein 1
SELECTION OF CITATIONS
SEARCH DETAIL