PTOV1 is overexpressed in human high-grade malignant tumors

SGK2, 14-3-3, and HUWE1 Cooperate to Control the Localization, Stability, and Function of the Oncoprotein PTOV1

PTOV1 is an oncogenic protein, initially identified in prostate cancer, that promotes proliferation, cell motility, and invasiveness. However, the mechanisms that regulate PTOV1 remain unclear. Here, we identify 14-3-3 as a PTOV1 interactor and show that high levels of 14-3-3 expression, like PTOV1, correlate with prostate cancer progression. We discover an SGK2-mediated phosphorylation of PTOV1 at S36, which is required for 14-3-3 binding. Disruption of the PTOV1-14-3-3 interaction results in an accumulation of PTOV1 in the nucleus and a proteasome-dependent reduction in PTOV1 protein levels. We find that loss of 14-3-3 binding leads to an increase in PTOV1 binding to the E3 ubiquitin ligase HUWE1, which promotes proteasomal degradation of PTOV1. Conversely, our data suggest that 14-3-3 stabilizes PTOV1 protein by sequestering PTOV1 in the cytosol and inhibiting its interaction with HUWE1. Finally, our data suggest that stabilization of the 14-3-3-bound form of PTOV1 promotes PTOV1-mediated expression of cJun, which drives cell-cycle progression in cancer. Together, these data provide a mechanism to understand the regulation of the oncoprotein PTOV1. IMPLICATIONS: These findings identify a potentially targetable mechanism that regulates the oncoprotein PTOV1.

Investigating the effects of chronic perinatal alcohol and combined nicotine and alcohol exposure on dopaminergic and non-dopaminergic neurons in the VTA

The ventral tegmental area (VTA) is the origin of dopaminergic neurons and the dopamine (DA) reward pathway. This pathway has been widely studied in addiction and drug reinforcement studies and is believed to be the central processing component of the reward circuit. In this study, we used a well-established rat model to expose mother dams to alcohol, nicotine-alcohol, and saline perinatally. DA and non-DA neurons collected from the VTA of the rat pups were used to study expression profiles of miRNAs and mRNAs. miRNA pathway interactions, putative miRNA-mRNA target pairs, and downstream modulated biological pathways were analyzed. In the DA neurons, 4607 genes were differentially upregulated and 4682 were differentially downregulated following nicotine-alcohol exposure. However, in the non-DA neurons, only 543 genes were differentially upregulated and 506 were differentially downregulated. Cell proliferation, differentiation, and survival pathways were enriched after the treatments. Specifically, in the PI3K/AKT signaling pathway, there were 41 miRNAs and 136 mRNAs differentially expressed in the DA neurons while only 16 miRNAs and 20 mRNAs were differentially expressed in the non-DA neurons after the nicotine-alcohol exposure. These results depicted that chronic nicotine and alcohol exposures during pregnancy differentially affect both miRNA and gene expression profiles more in DA than the non-DA neurons in the VTA. Understanding how the expression signatures representing specific neuronal subpopulations become enriched in the VTA after addictive substance administration helps us to identify how neuronal functions may be altered in the brain.

PTOV1 promotes cisplatin-induced chemotherapy resistance by activating the nuclear factor kappa B pathway in ovarian cancer

Chemotherapy resistance is a bottleneck for ovarian cancer treatment; therefore, revealing its regulatory mechanism is critical. In the present study, we found that prostate tumor overexpressed-1 (PTOV1) was upregulated significantly in ovarian cancer cells and tissues. Patients with high PTOV1 levels had a poor outcome. In addition, PTOV1 overexpression increased CDDP (cisplatin) resistance, while PTOV1 knockdown inhibited CDDP resistance, as determined using cell viability assays, apoptosis assays, and an animal model. Mechanistic analysis showed that PTOV1 increased nuclear factor kappa B (NF-κB) pathway activity, reflected by increased nuclear translocation of its p65 subunit and the phosphorylation of inhibitor of nuclear factor kappa-B kinase subunits alpha and beta, which are markers of NF-κB pathway activation. Inhibition of the NF-κB pathway in PTOV1-overexpressing ovarian cancer cells increased CDDP-induced apoptosis, suggesting that PTOV1 promoted chemotherapy resistance by activating the NF-κB pathway. In summary, we identified PTOV1 as a prognostic factor for patients with ovarian cancer. PTOV1 might be a target for inhibition of chemotherapy resistance.

Depleting PTOV1 sensitizes non-small cell lung cancer cells to chemotherapy through attenuating cancer stem cell traits

Background

Prostate tumor over expressed gene 1 (PTOV1) has been reported as an oncogene in several human cancers. However, the clinical significance and biological role of PTOV1 remain elusive in non-small cell lung cancer (NSCLC).

Methods

The Cancer Genome Atlas (TCGA) data and NCBI/GEO data mining, western blotting analysis and immunohistochemistry were employed to characterize the expression of PTOV1 in NSCLC cell lines and tissues. The clinical significance of PTOV1 in NSCLC was studied by immunohistochemistry statistical analysis and Kaplan–Meier Plotter database mining. A series of in-vivo and in-vitro assays, including colony formation, CCK-8 assays, flow cytometry, wound healing, trans-well assay, tumor sphere formation, quantitative PCR, gene set enrichment analysis (GSEA), immunostaining and xenografts tumor model, were performed to demonstrate the effects of PTOV1 on chemosensitivity of NSCLC cells and the underlying mechanisms.

Results

PTOV1 is overexpressed in NSCLC cell lines and tissues. High PTOV1 level indicates a short survival time and poor response to chemotherapy of NSCLC patients. Depleting PTOV1 increased sensitivity to chemotherapy drugs cisplatin and docetaxel by increasing cell apoptosis, inhibiting cell migration and invasion. Our study verified that depleting PTOV1 attenuated cancer stem cell traits through impairing DKK1/β-catenin signaling to enhance chemosensitivity of NSCLC cells.

Conclusion

These results suggest that PTOV1 plays an important role in the development and progression of human NSCLC and PTOV1 may serve as a therapeutic target for NSCLC patients.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1349-y) contains supplementary material, which is available to authorized users.

A novel DNA-binding motif in prostate tumor overexpressed-1 (PTOV1) required for the expression of ALDH1A1 and CCNG2 in cancer cells

PTOV1 is a transcription and translation regulator and a promoter of cancer progression. Its overexpression in prostate cancer induces transcription of drug resistance and self-renewal genes, and docetaxel resistance. Here we studied PTOV1 ability to directly activate the transcription of ALDH1A1 and CCNG2 by binding to specific promoter sequences. Chromatin immunoprecipitation and electrophoretic mobility shift assays identified a DNA-binding motif inside the PTOV-A domain with similarities to known AT-hooks that specifically interacts with ALDH1A1 and CCNG2 promoters. Mutation of this AT-hook-like sequence significantly decreased the expression of ALDH1A1 and CCNG2 promoted by PTOV1. Immunohistochemistry revealed the association of PTOV1 with mitotic chromosomes in high grade prostate, colon, bladder, and breast carcinomas. Overexpression of PTOV1, ALDH1A1, and CCNG2 significantly correlated with poor prognosis in prostate carcinomas and with shorter relapse-free survival in colon carcinoma. The previously described interaction with translation complexes and its direct binding to ALDH1A1 and CCNG2 promoters found here reveal the PTOV1 capacity to modulate the expression of critical genes at multiple levels in aggressive cancers. Remarkably, the AT-hook motifs in PTOV1 open possibilities for selective targeting its nuclear and/or cytoplasmic activities.

Prostate tumor overexpressed-1, in conjunction with human papillomavirus status, predicts outcome in early-stage human laryngeal squamous cell carcinoma

In human cancer, molecular markers combined with clinical characteristics are used increasingly to predict prognosis. Prostate tumor overexpressed-1 (PTOV1), first identified in prostate cancer, is a key factor in tumor progression and correlates with unfavorable clinical outcomes. HPV infection status was tested by HPV E6-targeted multiplex real-time PCR and p16 immunohistochemistry (IHC). Real-time PCR and western blotting analyses were used to examine the mRNA and protein expression levels of PTOV1 in eight paired LSCC samples. IHC was performed to assess PTOV1 protein expression in 196 paraffin-embedded, archived LSCC samples. PTOV1 protein and mRNA expression was increased in LSCC tissues compared with adjacent noncancerous tissue samples. High expression of PTOV1was significantly associated with advanced TNM stage by the X² test. Multivariate analysis revealed that PTOV1 and HPV status were independent prognostic indicators of overall survival (OS) and progression-free survival (PFS) (P = 0.001, P = 0.009 for OS, P = 0.005, P = 0.012 for PFS, respectively). Our study provides the first evidence that the combination of PTOV1 expression level and HPV status provides more prognostic information compared with HPV status alone with the significance still exists in the HPV negative subgroup.

Prostate Tumor Overexpressed-1 (PTOV1) promotes docetaxel-resistance and survival of castration resistant prostate cancer cells

Metastatic prostate cancer is presently incurable. The oncogenic protein PTOV1, first described in prostate cancer, was reported as overexpressed and significantly correlated with poor survival in numerous tumors. Here, we investigated the role of PTOV1 in prostate cancer survival to docetaxel and self-renewal ability. Transduction of PTOV1 in docetaxel-sensitive Du145 and PC3 cells significantly increased cell survival after docetaxel exposure and induced docetaxel-resistance genes expression (ABCB1, CCNG2 and TUBB2B). In addition, PTOV1 induced prostatospheres formation and self-renewal genes expression (ALDH1A1, LIN28A, MYC and NANOG). In contrast, Du145 and PC3 cells knockdown for PTOV1 significantly accumulated in the G2/M phase, presented a concomitant increased subG1 peak, and cell death by apoptosis. These effects were enhanced in docetaxel-resistant cells. Analyses of tumor datasets show that PTOV1 expression significantly correlated with prostate tumor grade, drug resistance (CCNG2) and self-renewal (ALDH1A1, MYC) markers. These genes are concurrently overexpressed in most metastatic lesions. Metastases also show PTOV1 genomic amplification in significant co-occurrence with docetaxel-resistance and self-renewal genes. Our findings identify PTOV1 as a promoter of docetaxel-resistance and self-renewal characteristics for castration resistant prostate cancer. The concomitant increased expression of PTOV1, ALDH1A1 and CCNG2 in primary tumors, may predict metastasis and bad prognosis.

Overexpressed PTOV1 associates with tumorigenesis and progression of esophageal squamous cell carcinoma

PTOV1 has been demonstrated to play an extensive role in many types of cancers. This study takes the first step to clarify the potential relationship between esophageal squamous cell carcinoma and PTOV1 expression and highlight the link between PTOV1 and the tumorigenesis, progression, and prognosis of esophageal squamous cell carcinoma. PTOV1 expression was detected by quantitative reverse transcription polymerase chain reaction and western blotting or immunohistochemical staining in esophageal squamous cell carcinoma cell lines, esophageal squamous cell carcinoma tissues, and its paired adjacent non-cancerous tissues. Moreover, we have analyzed the relationship between PTOV1 expression and clinicopathological features of esophageal squamous cell carcinoma. Survival analysis and Cox regression analysis were used to assess its prognostic significance. We found that PTOV1 expression was significantly higher in the esophageal squamous cell carcinoma cell lines and tissues at messenger RNA level (p < 0.001) and protein level (p < 0.001). Gender, tumor size, or differentiation was tightly associated with the PTOV1 expression. Lymph node involvement (p < 0.001) and TNM stage (p < 0.001) promoted a high PTOV1 expression. A prognostic significance of PTOV1 was also found by Log-rank method, and the overexpression of PTOV1 was related to a shorter OS and DFS. Multiple Cox regression analysis indicated overexpressed PTOV1 as an independent indicator for adverse prognosis. In conclusion, this study takes the lead to demonstrate that the overexpressed PTOV1 plays a vital role in the tumorigenesis and progression of esophageal squamous cell carcinoma, and it is potentially a valuable prognostic predicator and new chemotherapeutic target for esophageal squamous cell carcinoma.

Prostate tumor overexpressed 1 expression in invasive urothelial carcinoma

PURPOSE

To determine the expression patterns of the proliferation marker prostate tumor overexpressed 1 (PTOV1) in invasive urothelial cancer (UC).

METHODS

Corresponding UC and benign samples from paraffin-embedded tissue of 102 patients treated with cystectomy for invasive UC were immunohistochemically (IHC) assessed for PTOV1. Expression was evaluated gradually separated for cytoplasmic and nuclear staining. Results were correlated to histological and clinical data. To correlate PTOV1 expression with molecular subtypes of UC, analysis of PTOV1 RNA expression data of the Cancer Genome Atlas UC cohort was performed.

RESULTS

PTOV1 expression was present in UC and benign urothelium, whereby nuclear staining was significantly more frequent in UC tissue (p = 0.0004). Lower cytoplasmic expression was significantly associated with pathological stage >pT2 (p = 0.0014) and grade ≥G3 (p = 0.0041), respectively. IHC expression patterns did not show correlation to survival data. PTOV1 RNA expression correlated with features of the luminal UC subtype.

CONCLUSIONS

Subcellular distribution seems to be the most important feature of PTOV1 expression in UC. Nuclear localization of PTOV1 along with cytoplasmic decrease in PTOV1 expression was identified as putative surrogate for PTOV1-associated cellular proliferation and dedifferentiation in UC. The functional relevance as well as the potential role of PTOV1 as a biomarker in UC remains to be specified in future studies.

Prostate Tumor Overexpressed 1 (PTOV1) Is a Novel Prognostic Marker for Nasopharyngeal Carcinoma Progression and Poor Survival Outcomes

BACKGROUND

Prostate tumor overexpressed 1 (PTOV1) has been reported to contribute to increased cancer proliferation. However, the clinical significance of PTOV1 in the development and progression of nasopharyngeal carcinoma (NPC) is unclear. Our study aimed to investigate the expression pattern of PTOV1 in NPC and its correlation with clinicopathological features of patients.

METHODS

Western blotting and real-time PCR were conducted to examine PTOV1 expression levels in NPC cell lines and biopsy tissues compared with normal controls. Immunohistochemistry (IHC) was performed to analyze PTOV1 protein expression in paraffin-embedded tissues from 123 patients. Statistical analyses were applied to evaluate the clinical significance of PTOV1 expression.

RESULTS

PTOV1 mRNA and protein levels were upregulated in NPC cell lines and clinical samples. IHC analyses showed that PTOV1 was highly expressed in 68 (55.3%) of 123 NPC specimens. Statistical analysis revealed that PTOV1 expression was significantly correlated with clinical stage (P < 0.001), T classification (P = 0.042) and N classification (P = 0.001). Patients with a higher PTOV1 expression had shorter overall survival compared with those with a lower PTOV1 expression level, especially in lower N stage patients. Multivariate analyses suggested that PTOV1 expression was an independent prognostic marker for survival in NPC patients.

CONCLUSIONS

Our data demonstrated that PTOV1 overexpression is associated with poor survival outcomes of NPC patients, especially in N0-1 patients. Hence, PTOV1 may help to detect early lymph node metastasis of NPC patients and serve as an independent prognostic biomarker for human NPC.

A Phosphoproteomic Comparison of B-RAFV600E and MKK1/2 Inhibitors in Melanoma Cells

Inhibitors of oncogenic B-RAF(V600E) and MKK1/2 have yielded remarkable responses in B-RAF(V600E)-positive melanoma patients. However, the efficacy of these inhibitors is limited by the inevitable onset of resistance. Despite the fact that these inhibitors target the same pathway, combination treatment with B-RAF(V600E) and MKK1/2 inhibitors has been shown to improve both response rates and progression-free survival in B-RAF(V600E) melanoma patients. To provide insight into the molecular nature of the combinatorial response, we used quantitative mass spectrometry to characterize the inhibitor-dependent phosphoproteome of human melanoma cells treated with the B-RAF(V600E) inhibitor PLX4032 (vemurafenib) or the MKK1/2 inhibitor AZD6244 (selumetinib). In three replicate experiments, we quantified changes at a total of 23,986 phosphosites on 4784 proteins. This included 1317 phosphosites that reproducibly decreased in response to at least one inhibitor. Phosphosites that responded to both inhibitors grouped into networks that included the nuclear pore complex, growth factor signaling, and transcriptional regulators. Although the majority of phosphosites were responsive to both inhibitors, we identified 16 sites that decreased only in response to PLX4032, suggesting rare instances where oncogenic B-RAF signaling occurs in an MKK1/2-independent manner. Only two phosphosites were identified that appeared to be uniquely responsive to AZD6244. When cells were treated with the combination of AZD6244 and PLX4032 at subsaturating concentrations (30 nm), responses at nearly all phosphosites were additive. We conclude that AZD6244 does not substantially widen the range of phosphosites inhibited by PLX4032 and that the benefit of the drug combination is best explained by their additive effects on suppressing ERK1/2 signaling. Comparison of our results to another recent ERK1/2 phosphoproteomics study revealed a surprising degree of variability in the sensitivity of phosphosites to MKK1/2 inhibitors in human cell lines, revealing unexpected cell specificity in the molecular responses to pathway activation.

Prostate tumor overexpressed 1 is a novel prognostic marker for hepatocellular carcinoma progression and overall patient survival

The gene prostate tumor overexpressed 1 (PTOV1) was first found to be upregulated in prostate cancer. This upregulation increased tumor cell proliferation, retinoic acid resistance, and migration. This study investigated the expression and prognostic significance of PTOV1 in hepatocellular carcinoma (HCC). Real-time Polymerase Chain Reaction and western blot analysis were performed to examine PTOV1 expression in 11 HCC cell lines and 2 normal hepatic cell lines. PTOV1 expression levels were also determined in 8 pairs of tissue samples taken from primary HCC tumors and the matched adjacent noncancerous liver tissue from the same patient. Immunohistochemistry assays assessed PTOV1 protein expression in paraffin-embedded clinical samples taken from 215 HCC patients. The correlation of PTOV1 expression with the clinicopathological parameters was evaluated along with the prognostic impact of PTOV1 expression in these HCC patients. PTOV1 mRNA and protein were overexpressed in HCC cell lines compared with normal liver cell lines and were overexpressed in primary HCC samples compared with the matched noncancerous liver tissue samples. In the paraffin-embedded tissue samples from 215 HCC patients, PTOV1 protein expression was significantly correlated with T classification, N classification, clinical stage, and serum α-fetoprotein. HCC patients with higher PTOV1 expression had shorter survival times than patients with lower PTOV1 expression. Our study demonstrated that PTOV1 overexpression is correlated with increased aggressiveness of HCC and could be a prognostic biomarker for patients with HCC.

Increased PTOV1 expression is related to poor prognosis in epithelial ovarian cancer

Altered expression of prostate tumor overexpressed-1 (PTOV1) is observed in various types of human cancers. However, the role of PTOV1 in epithelial ovarian cancer (EOC) remains unclear. PTOV1 messenger (m)RNA expression in EOC patients was evaluated by quantitative real-time PCR (qRT-PCR). PTOV1 protein expression was also analyzed in archived paraffin-embedded EOC tissues using immunohistochemistry (IHC), and its association with overall survival of patients was analyzed by statistical analysis. Results from qRT-PCR analysis show that the expression level of PTOV1 mRNA was significantly higher in tumor tissues of EOC, compared to that in adjacent noncancerous tissues (P < 0.001). IHC staining showed that high expression of PTOV1 was detected in 57.2 % (87/152) of EOC cases. High expression of PTOV1 was significantly associated with pathological grade (P = 0.029) and clinical stage (P = 0.001). Moreover, the results of Kaplan-Meier analysis indicated that a high expression level of PTOV1 resulted in a significantly poor prognosis of EOC patients. Multivariate analysis showed that high expression of PTOV1 was an independent prognostic factor for overall survival (P < 0.001). In conclusion, PTOV1 protein abnormal expression might contribute to the malignant progression of EOC. High expression of PTOV1 predicts poor prognosis in patients with EOC.

Overexpression of prostate tumor overexpressed 1 correlates with tumor progression and predicts poor prognosis in breast cancer

BACKGROUND

Prostate tumor overexpressed 1 (PTOV1) was demonstrated to play an important role in cancer progression and was correlated with unfavorable clinical outcome. However, the clinical role of PTOV1 in cancer remains largely unknown. This study aimed to investigate the expression and clinicopathological significance of PTOV1 in breast cancer.

METHODS

The mRNA and protein expression levels of PTOV1 were analyzed in 12 breast cancer cell lines and eight paired breast cancer tumors by semi-quantitative real time-PCR and western blotting, respectively. Immunohistochemistry was performed to assess PTOV1 protein expression in 169 paraffin-embedded, archived breast cancer samples. Survival analysis and Cox regression analysis were performed to investigate the clinicopathological significance of PTOV1 expression.

RESULTS

Our data revealed that PTOV1 was frequently overexpressed in breast cancer cell lines compared to normal human breast epithelial cells and in primary breast cancer samples compared to adjacent noncancerous breast tissues, at both the mRNA and protein levels. Moreover, high expression of PTOV1 in breast cancer is strongly associated with clinicopathological characteristics and estrogen receptor expression status (P = 0.003). Breast cancer patients with higher PTOV1 expression had substantially shorter survival times than patients with lower PTOV1 expression (P < 0.001). Univariate and multivariate analysis revealed that PTOV1 might be an independent prognostic factor for breast cancer patients (P = 0.005).

CONCLUSIONS

Our study showed that PTOV1 is upregulated in breast cancer cell lines and clinical samples, and its expression was positively associated with progression and aggressiveness of breast cancer, suggesting that PTOV1 could serve as an independent prognostic marker.

Prostate tumor OVerexpressed-1 (PTOV1) down-regulates HES1 and HEY1 notch targets genes and promotes prostate cancer progression

BACKGROUND

PTOV1 is an adaptor protein with functions in diverse processes, including gene transcription and protein translation, whose overexpression is associated with a higher proliferation index and tumor grade in prostate cancer (PC) and other neoplasms. Here we report its interaction with the Notch pathway and its involvement in PC progression.

METHODS

Stable PTOV1 knockdown or overexpression were performed by lentiviral transduction. Protein interactions were analyzed by co-immunoprecipitation, pull-down and/or immunofluorescence. Endogenous gene expression was analyzed by real time RT-PCR and/or Western blotting. Exogenous promoter activities were studied by luciferase assays. Gene promoter interactions were analyzed by chromatin immunoprecipitation assays (ChIP). In vivo studies were performed in the Drosophila melanogaster wing, the SCID-Beige mouse model, and human prostate cancer tissues and metastasis. The Excel package was used for statistical analysis.

RESULTS

Knockdown of PTOV1 in prostate epithelial cells and HaCaT skin keratinocytes caused the upregulation, and overexpression of PTOV1 the downregulation, of the Notch target genes HEY1 and HES1, suggesting that PTOV1 counteracts Notch signaling. Under conditions of inactive Notch signaling, endogenous PTOV1 associated with the HEY1 and HES1 promoters, together with components of the Notch repressor complex. Conversely, expression of active Notch1 provoked the dismissal of PTOV1 from these promoters. The antagonist role of PTOV1 on Notch activity was corroborated in the Drosophila melanogaster wing, where human PTOV1 exacerbated Notch deletion mutant phenotypes and suppressed the effects of constitutively active Notch. PTOV1 was required for optimal in vitro invasiveness and anchorage-independent growth of PC-3 cells, activities counteracted by Notch, and for their efficient growth and metastatic spread in vivo. In prostate tumors, the overexpression of PTOV1 was associated with decreased expression of HEY1 and HES1, and this correlation was significant in metastatic lesions.

CONCLUSIONS

High levels of the adaptor protein PTOV1 counteract the transcriptional activity of Notch. Our evidences link the pro-oncogenic and pro-metastatic effects of PTOV1 in prostate cancer to its inhibitory activity on Notch signaling and are supportive of a tumor suppressor role of Notch in prostate cancer progression.

Regulation of protein translation and c-Jun expression by prostate tumor overexpressed 1

Prostate tumor overexpressed-1 (PTOV1), a modulator of the Mediator transcriptional regulatory complex, is expressed at high levels in prostate cancer and other neoplasias in association with a more aggressive disease. Here we show that PTOV1 interacts directly with receptor of activated protein C kinase 1 (RACK1), a regulator of protein kinase C and Jun signaling and also a component of the 40S ribosome. Consistent with this interaction, PTOV1 was associated with ribosomes and its overexpression promoted global protein synthesis in prostate cancer cells and COS-7 fibroblasts in a mTORC1-dependent manner. Transfection of ectopic PTOV1 enhanced the expression of c-Jun protein without affecting the levels of c-Jun or RACK1 mRNA. Conversely, knockdown of PTOV1 caused significant declines in global protein synthesis and c-Jun protein levels. High levels of PTOV1 stimulated the motility and invasiveness of prostate cancer cells, which required c-Jun, whereas knockdown of PTOV1 strongly inhibited the tumorigenic and metastatic potentials of PC-3 prostate cancer cells. In human prostate cancer samples, the expression of high levels of PTOV1 in primary and metastatic tumors was significantly associated with increased nuclear localization of active c-Jun. These results unveil new functions of PTOV1 in the regulation of protein translation and in the progression of prostate cancer to an invasive and metastatic disease.

Immunohistochemical expression of prostate tumour overexpressed 1 (PTOV1) in atypical adenomatous hyperplasia (AAH) of the prostate: additional evidence linking (AAH) to adenocarcinoma

BACKGROUND

Prostate tumour overexpressed 1, PTOV1, was recently identified as a novel gene and protein during a differential display screening for genes overexpressed in prostate cancer (PCa). It has been suggested that overexpression of PTOV1 can contribute to the proliferative status of prostate tumour cells and thus to their biological behaviour.

METHODS

PTOV1 and Ki67 were immunohistochemically evaluated in PCa, atypical adenomatous hyperplasia (AAH), high-grade prostatic intraepithelial neoplasia (HGPIN), and normal-looking epithelium (NEp) of the transition zone (TZ) in 40 radical prostatectomies with pT2a Gleason score 6 PCa (20 with AAH and 20 with HGPIN) and in 10 simple prostatectomies (SPs) (5 with AAH and 5 with HGPIN). The aim was to evaluate PTOV1 protein expression as a marker for tumor development and progression from AAH to PCa.

RESULTS

The proportions of PTOV1 and Ki67 positive cells increased from NEp through AAH and HGPIN to PCa. In particular, the mean Hscore of PTOV1 expression in AAH was 110.90, i.e., close to three times that of NEp (40.76), similar to that of HGPIN (105.61) and lower than that of PCa (137.03). The mean values in AAH and HGPIN associated with cancer in the RPs were slightly higher than in the SPs.

CONCLUSION

Our findings related to PTOV1 expression in AAH, similar to those in HGPIN, provide additional evidence linking AAH to prostatic adenocarcinoma.

Is there a role for prostate tumour overexpressed-1 in the diagnosis of HGPIN and of prostatic adenocarcinoma? A comparison with alpha-methylacyl CoA racemase

Prostate Tumour Overexpressed-1 (PTOV1) was recently identified as a novel gene and protein during a differential display screening for genes overexpressed in prostate cancer (PCa). Alpha-Methyl-CoA racemase (AMACR) mRNA was identified as being overexpressed in PCa. PTOV1 and racemase were immunohistochemically evaluated in PCa, high-grade prostatic intraepithelial neoplasia (HGPIN), atrophy and normal-looking epithelium (NEp) in 20 radical prostatectomies (RPs) with pT2a Gleason score 6 prostate cancer with the aim of analyzing the differences in marker expression between PTOV1 and AMACR. The level of expression of PTOV1 and AMACR increased from NEp and atrophy through HGPIN, away from and adjacent to prostate cancer, to PCa. With the ROC curve analysis the overall accuracy in distinguishing PCa vs HGPIN away from and adjacent to cancer was higher for AMACR than for PTOV1. In conclusion, AMACR can be considered a more accurate marker than PTOV1 in the identification of HGPIN and of PCa. However, PTOV1 may aid in the diagnosis of PCa, at least to supplement AMACR as another positive marker of carcinoma and to potentially increase diagnostic accuracy.

Immunohistochemical expression of prostate tumor overexpressed 1 in cystoprostatectomies with incidental and insignificant prostate cancer. Further evidence for field effect in prostatic carcinogenesis

Prostate tumor overexpressed 1 was recently identified as a novel gene and protein during a differential display screening for genes overexpressed in prostate cancer. It has been suggested that overexpression of prostate tumor overexpressed 1 can contribute to the proliferative status of prostate tumor cells and, thus, to their biologic behavior. Prostate tumor overexpressed 1 and Ki-67 were immunohistochemically evaluated in prostate cancer, high-grade prostatic intraepithelial neoplasia, and normal-looking epithelium in 20 cystoprostatectomies and 20 radical prostatectomies with pT2a Gleason score 6 prostate cancer. The aim was to see whether there were differences in marker expression between cystoprostatectomies and radical prostatectomies. The proportions of prostate tumor overexpressed 1- and Ki-67-positive cells in the cystoprostatectomies and radical prostatectomies increased from normal-looking epithelium through high-grade prostatic intraepithelial neoplasia, away from and adjacent to prostate cancer, to prostate cancer. Prostate tumor overexpressed 1 expression in prostate cancer in cystoprostatectomies was lower than in radical prostatectomies, the differences being significant; there were significant differences in Ki-67 indices. In conclusion, our findings related to prostate tumor overexpressed 1 expression in high-grade prostatic intraepithelial neoplasia, evaluated adjacent and away from prostate cancer, and in incidental and clinical cancers give further support to the concept of field effect in prostatic carcinogenesis as well as to differences in the process of prostatic carcinogenesis between cystoprostatectomies and radical prostatectomies.