Expression and regulation of prostate androgen regulated transcript-1 (PART-1) and identification of differential expression in prostatic cancer

Long non-coding RNAs in cancer: multifaceted roles and potential targets for immunotherapy

Cancer remains a major global health concern with high mortality rates mainly due to late diagnosis and poor prognosis. Long non-coding RNAs (lncRNAs) are emerging as key regulators of gene expression in human cancer, functioning through various mechanisms including as competing endogenous RNAs (ceRNAs) and indirectly regulating miRNA expression. LncRNAs have been found to have both oncogenic and tumor-suppressive roles in cancer, with the former promoting cancer cell proliferation, migration, invasion, and poor prognosis. Recent research has shown that lncRNAs are expressed in various immune cells and are involved in cancer cell immune escape and the modulation of the tumor microenvironment, thus highlighting their potential as targets for cancer immunotherapy. Targeting lncRNAs in cancer or immune cells could enhance the anti-tumor immune response and improve cancer immunotherapy outcomes. However, further research is required to fully understand the functional roles of lncRNAs in cancer and the immune system and their potential as targets for cancer immunotherapy. This review offers a comprehensive examination of the multifaceted roles of lncRNAs in human cancers, with a focus on their potential as targets for cancer immunotherapy. By exploring the intricate mechanisms underlying lncRNA-mediated regulation of cancer cell proliferation, invasion, and immune evasion, we provide insights into the diverse therapeutic applications of these molecules.

Reduced PDE4D7 in prostate cancer correlates with genomic downregulation within the upstream PDE4D coding region

Aim

PDE4D7 expression is significantly associated with prostate cancer (PCa) progression, representing an attractive prognostic biomarker. We sought to determine whether other genes in the PDE4D coding region were associated.

Patients & methods

RNA from biopsy punch samples of resected tumor tissue was analyzed via RNA sequencing. RT-qPCR was used to determine PDE4D7 score.

Results

Numerous genomic sequences within the PDE4D coding region on Chr5q12 revealed similar mRNA expression profiles to PDE4D7. PART1 had a significantly similar expression pattern to PDE4D7 across samples, correlating with disease progression. However, many other genes also exhibited matched expression to PDE4D7, including miRNAs and lncRNAs.

Conclusion

These novel PDE4D7-associated genes, many of which are previously uncharacterized in cancer, represent putative PCa biomarkers and could have mechanistic roles in PCa progression.

A review on the role of long non-coding RNA prostate androgen-regulated transcript 1 (PART1) in the etiology of different disorders

LncRNA prostate androgen-regulated transcript 1 (PART1) is an important lncRNA in the carcinogenesis whose role has been firstly unraveled in prostate cancer. Expression of this lncRNA is activated by androgen in prostate cancer cells. In addition, this lncRNA has a role in the pathogenesis intervertebral disc degeneration, myocardial ischemia-reperfusion injury, osteoarthritis, osteoporosis and Parkinson's disease. Diagnostic role of PART1 has been assessed in some types of cancers. Moreover, dysregulation of PART1 expression is regarded as a prognostic factor in a variety of cancers. The current review provides a concise but comprehensive summary of the role of PART1 in different cancers and non-malignant disorders.

Long non‑coding RNA PART1: dual role in cancer

Increasing evidence has shown that long non-coding RNAs (lncRNAs), which are non-coding endogenous single-stranded RNAs, play an essential role in various physiological and pathological processes through transcriptional interference, post-transcriptional regulation, and epigenetic modification. Moreover, lncRNAs, as oncogenes or tumor suppressor genes, play an important role in the occurrence and development of human cancers. Prostate androgen-regulated transcript 1 (PART1) was initially identified as a carcinogenic lncRNA in prostate adenomas. The upregulated expression of PART1 plays a tumor-promoting role in liver, prostate, lung cancers, and other tumors. In contrast, the expression of PART1 is downregulated in esophageal squamous cell carcinoma, glioma, and other tumors, which may inhibit the tumor. PART1 plays a dual role in cancer and regulates cell proliferation, apoptosis, invasion, and metastasis through a variety of potential mechanisms. These findings suggest that PART1 is a promising tumor biomarker and therapeutic target. This article reviews the biological functions, related mechanisms, and potential clinical significance of PART1 in a variety of human cancers.

The Role of Tumor-related LncRNA PART1 in cancer

BACKGROUND

As we all know, long non-coding RNA (lncRNA) affects tumor progression, which has caused a great upsurge in recent years. It can also affect the growth, migration, and invasion of tumors. When we refer to the abnormal expression of lncRNA, we will find it associated with malignant tumors. In addition, lncRNA has been proved to be a key targeted gene for the treatment of some diseases. PART1, a member of lncRNA, has been reported as a regulator in the process of tumor occurrence and development. This study aims to reveal the biological functions, specific mechanisms, and clinical significance of PART1 in various tumor cells.

METHODS

Through the careful search of PUBMED, the mechanisms of the effect of PART1 on tumorigenesis and development are summarized.

RESULTS

On the one hand, the up-regulated expression of PART1 plays a tumor-promoting role in tumors, including lung cancer, prostate cancer, bladder cancer and so on. On the other hand, PART1 is down-regulated in gastric cancer, glioma and other tumors to play a tumor inhibitory role. In addition, PART1 regulates tumor growth mainly by targeting microRNA such as miR-635, directly regulating the expression of proteins such as FUS/EZH2, affecting signal pathways such as the Toll-like receptor pathway, or regulating immune cells.

CONCLUSION

PART1 is closely related to tumors by regulating a variety of molecular mechanisms. In addition, PART1 can be used as a clinical marker for the early diagnosis of tumors and plays an important role in tumor-targeted therapy.

Long non-coding RNA PART1 predicts a poor prognosis and promotes the malignant progression of pancreatic cancer by sponging miR-122

BACKGROUND AND OBJECTIVES

Long non-coding RNA (lncRNA) prostate androgen-regulated transcript 1 (PART1) was previously shown to exert an oncogenic role in several human cancers. However, whether PART1 is associated with the malignant progression of pancreatic cancer remains unclear. In the current study, we aimed to identify the role and potential mechanism of PART1 in pancreatic cancer.

METHODS

qRT-PCR was applied to detect PART1 expression in 45 cases of pancreatic cancer patients. The chi-square test was performed to assess the association between PART1 expression and clinicopathologic features, and Kaplan-Meier method was applied to evaluate overall survival. In vitro CCK-8, transwell invasion, and flow cytometry assays were applied to detect the effects of PART1 on cell proliferation, invasion, and apoptosis, respectively. Luciferase reporter and RNA immunoprecipitation assays were used to identify the regulatory mechanism between PART1 and miR-122.

RESULTS

PART1 expression was upregulated in pancreatic cancer tissues and cell lines. High PART1 expression was closely correlated with tumor size, T classification, clinical stage, and vascular invasion, and predicted a poor overall survival. PART1 knockdown significantly suppressed cell proliferation and invasion abilities of pancreatic cancer but promoted cell apoptosis. PART1 was found to serve as a molecular sponge of miR-122, and miR-122 inhibition partially reversed the inhibitory phenotypes of PART1 knockdown on pancreatic cancer cells.

CONCLUSIONS

PART1 promotes the malignant progression of pancreatic cancer by sponging miR-122. The PART1/miR-122 axis might be a promising target for anticancer therapy in patients with pancreatic cancer.

LncRNA prostate androgen-regulated transcript 1 (PART 1) functions as an oncogene in osteosarcoma via sponging miR-20b-5p to upregulate BAMBI

Background

Osteosarcoma (OS) is an aggressive bone cancer that most commonly affects adolescents and children. Emerging studies have shown that long noncoding RNA (lncRNA) performs essential roles in the occurrence and development of many tumors. Prostate androgen-regulated transcript 1 (PART 1) has been reported as a tumor oncogene; despite this, the mechanisms underlying its involvement in OS are unclear.

Methods

OS and paired normal tissue samples were obtained, and gene expressions were detected by real time-quantitative polymerase chain reaction (RT-qPCR). The functions of PART 1 in OS cell proliferation, invasion, and migration were determined by Cell Counting Kit-8 (CCK-8) and Transwell assays. Furthermore, the binding sites of PART 1 and miR-20b-5p as well as those between miR-20b-5p and bone morphogenic protein and activin membrane-bound inhibitor homolog (BAMBI) were verified by bioinformatics analysis and dual-luciferase reporter assay.

Results

Our study found obvious overexpression of PART 1 in OS tissues and cells. Furthermore, PART 1 overexpression facilitated OS cell proliferation, invasion, and migration. Further mechanistic investigations revealed that PART 1 could sponge to miR-20b-5p, which was expressed at a low level in OS tissues and cells. Importantly, miR-20b-5p overexpression inhibited OS cell proliferation, invasion, and migration. Additionally, BAMBI was confirmed as a downstream gene of miR-20b-5p, and its expression was reversely modulated by miR-20b-5p and positively modulated by PART 1. Rescue experiments suggested that BAMBI was involved in PART 1-mediated promotion of OS progression.

Conclusions

PART 1 serves as a competing endogenous RNA to promote OS tumorigenesis via its regulation of the miR-20b-5p/BAMBI axis, which may provide a promising therapeutic biomarkers for OS patients.

LncRNA PART1 promotes lung squamous cell carcinoma progression via miR-185-5p/Six1 axis

Dysregulation of the long non-coding RNA prostate androgen regulated transcript 1 (lncRNA PART1) is involved in the tumorigenesis of various cancers. However, little is known about its function and molecular mechanism in the development of lung squamous cell carcinoma (LSCC). In this study, we examined the expression of PART1 in LSCC clinical tissue samples and cell lines, and gain- and loss-of-function experiments were performed to explore the function of PART1 in LSCC proliferation, invasion and migration. We found that PART1 was overexpressed in both LSCC tissues and cell lines. Functional studies revealed that PART1 knockdown significantly suppressed cell proliferation, invasion and migration but enhanced apoptosis in LSCC cells, whereas overexpression of PART1 showed the opposite results. Mechanistically, we identified that PART1 acted as a sponge of miR-185-5p, and sineoculis homeobox homolog 1 (Six1) was a direct downstream target of miR-185-5p. Moreover, restoration of miR-185-5p or silencing of Six1 partially abolished the oncogenic effect of PART1 in LSCC cells. Clinically, The areas under the receiver operating characteristic (ROC) curve of PART1, miR-185-5p, and Six1 were 0.7857, 0.7332, 0.8112, respectively. Notably, high PART1, low miR-185-5p, and high Six1 expressions were significantly associated with severe clinical parameters and were the independent risk factors for poor prognosis of LSCC patients. Thus, we concluded that the PART1/miR-185-5p/Six1 axis might serve as a novel biomarker for the diagnosis and treatment of LSCC.

A modern era of personalized medicine in the diagnosis, prognosis, and treatment of prostate cancer

The present era is witnessing rapid advancements in the field of medical informatics and modern healthcare management. The role of translational bioinformatics (TBI), an infant discipline in the field of medical informatics, is pivotal in this revolution. The development of high-throughput technologies [e.g., microarrays, next-generation sequencing (NGS)] has propelled TBI to the next stage in this modern era of medical informatics. In this review, we assess the promising translational outcomes of microarray- and NGS-based discovery of genes, proteins, micro RNAs, and other active biological compounds aiding in the diagnosis, prognosis, and therapy of prostate cancer (PCa) to improve treatment strategies at the localized and/or metastatic stages in patients. Several promising candidate biomarkers in circulating blood (miR-25-3p and miR-18b-5p), urine (miR-95, miR-21, miR-19a, and miR-19b), and prostatic secretions (miR-203) have been identified. AURKA and MYCN, novel candidate biomarkers, were found to be specifically expressed in neuroendocrine PCa. The use of BTNL2 gene mutations and inflammasomes as biomarkers in immune function-mediated, inherited PCa has also been elucidated based on NGS data. Although TBI discoveries can benefit clinical performance metrics, the translational potential and the in vivo performance of TBI outcomes need to be verified. In conclusion, TBI aids in the effective clinical management of PCa; furthermore, the fate of personalized/precision medicine mostly relies on the enhanced diagnostic, prognostic, and therapeutic potential of TBI.

Inhibition of lncRNA PART1 Chemosensitizes Wild Type but Not KRAS Mutant NSCLC Cells

Background

Lung cancer has the highest incidence among solid tumors in men and is the third most common cancer in women. Despite improved understanding of genomic and mutational landscape in non-small cell lung cancer (NSCLC), the five-year survival in these patients has remained stagnant at a dismal 15%. The first line of treatment commonly adapted for NSCLC patients with somatic mutation in EGFR is tyrosine kinase inhibitor gefitinib or erlotinib. EGFR mutant cells seem to be intrinsically sensitive to tyrosine kinase inhibitors; however, the remaining 20-30% patients are resistant to tyrosine kinase inhibitor.

Materials and Methods

Here we show, using in vitro normal and NSCLS cell lines, that the lncRNA Prostate androgen-regulated transcript 1 (PART1) is expressed at higher levels in NSCLC cells compared to normal lung epithelial cell line, corroborating two earlier studies.

Results

We additionally show that these cells are resistant to erlotinib which is reversed in some, but not all, cell lines following suppression of PART1 expression. The differential response to erlotinib following siRNA-mediated knockdown of PART1 was found to be related to the mutational status of KRAS. Only in cells with wild-type KRAS suppression of PART1 sensitized them to erlotinib. Knockdown of mutant KRAS did not sensitize those cell lines to erlotinib. But knockdown of mutant KRAS along with suppression of PART1 sensitized the cells to treatment with erlotinib. The results from the study reveal a yet undefined and important role of lncRNA PART1 in defining sensitivity to erlotinib. This action is mediated by mutation status of KRAS.

Conclusion

Even though preliminary, our results indicate PART1 might be a potential candidate for targeted therapy or used as a predictor of chemosensitivity in patients with NSCLC.

Downregulated Long Noncoding RNA PART1 Inhibits Proliferation and Promotes Apoptosis in Bladder Cancer

OBJECTIVE

In this study, we aimed to clarify the effects of long noncoding ribonucleic acid prostrate androgen-regulated transcript-1 on bladder cancer cell proliferation and apoptosis.

METHODS

Microarrays were implemented to investigate the long noncoding ribonucleic acid expression profiles in bladder cancer tissue (N = 9) and in noncancer bladder tissue (N = 5). Relative prostrate androgen-regulated transcript-1 expression levels in tissue samples or cell lines were detected by real-time quantitative reverse transcription-polymerase chain reaction. Prostrate androgen-regulated transcript-1 expression was enhanced by the transfection of pcDNA3.1-prostrate androgen-regulated transcript-1 and downregulated by the infection with pcMV-sh prostrate androgen-regulated transcript-1. Additionally, cell proliferation and apoptosis were measured by the cell counting kit-8 assay and flow cytometry, respectively. Cell invasion was determined by a Transwell assay.

RESULTS

Prostrate androgen-regulated transcript-1 expression was upregulated in bladder cancer tissues compared to adjacent nontumor tissues. Furthermore, prostrate androgen-regulated transcript-1 levels were successfully upregulated by pcDNA3.1-prostrate androgen-regulated transcript-1 and depleted by pCMV-sh prostrate androgen-regulated transcript-1 in bladder cancer cell lines (5637, T24). Enhanced prostrate androgen-regulated transcript-1 expression promoted cell proliferation and invasion and inhibited cell apoptosis. However, knockdown of prostrate androgen-regulated transcript-1 expression inhibited cell proliferation and invasion and induced cell apoptosis.

CONCLUSION

In summary, these data suggest that the knockdown of prostrate androgen-regulated transcript-1 represents a tumor suppressor player in bladder cancer and contributes to the inhibition of tumor proliferation, the promotion of cell apoptosis, and the suppression of cell invasion. Prostrate androgen-regulated transcript-1 may function as a new prognostic biomarker and as a feasible therapeutic target for patients with bladder cancer.

A novel risk score system for assessment of ovarian cancer based on co-expression network analysis and expression level of five lncRNAs

Background

Ovarian cancer (OC) is the most deadly gynaecological cancer, contributing significantly to female cancer-related deaths worldwide. Improving the outlook for OC patients depends on the identification of more reliable prognostic biomarkers for early diagnosis and survival prediction. The various roles of long non-coding RNAs (lncRNAs) in OC have attracted increasing attention. This study aimed to identify a lncRNA-based signature for survival prediction in OC patients.

Methods

RNA expression data and clinical information from a large number of OC patients were downloaded from a public database. These data were regarded as a training set to construct a weighed gene co-expression network analysis (WGCNA) network, mine stable modules, and screen differentially expressed lncRNAs. The prognostic lncRNAs were screened using univariate Cox regression analysis and the optimal prognosis lncRNA combination was screened using a Cox-PH model. The finalised lncRNA combination was used to construct the risk score system, which was validated and assessed for effectiveness using other independent datasets. Further functional pathway enrichment was performed using gene set enrichment analysis (GSEA).

Results

A co-expression network was constructed and four stable modules with OC-related biological functions were obtained. A total of 19 lncRNAs significantly related to prognosis of ovarian cancer were obtained using univariate Cox regression analysis, and the 5 prognostic signature lncRNAs GAS5, HCP5, PART1, SNHG11, and SNHG5 were used to establish a risk assessment system. The reliability of the prognostic scoring system was further confirmed using validation sets, which indicated that the risk assessment system could be used as an independent prognostic factor. Pathway enrichment analysis revealed that the network modules related to the above five prognostic genes were significantly associated with cell local adhesion, cancer signaling pathways, JAK-STAT signalling, and endogenous cell receptor interaction.

Conclusions

The risk score system established in this study could provide a novel reliable method to identify individuals at high risk of OC. In addition, the five prognostic lncRNAs identified here are promising potential prognostic biomarkers that could help to elucidate the pathogenesis of OC.

Creating a potential diagnostic for prostate cancer risk stratification (InformMDx™) by translating novel scientific discoveries concerning cAMP degrading phosphodiesterase-4D7 (PDE4D7)

Increased PSA-based screening for prostate cancer has resulted in a growing number of diagnosed cases. However, around half of these are ‘indolent’, neither metastasizing nor leading to disease specific death. Treating non-progressing tumours with invasive therapies is currently regarded as unnecessary over-treatment with patients being considered for conservative regimens, such as active surveillance (AS). However, this raises both compliance and protocol issues. Great clinical benefit could accrue from a biomarker able to predict long-term patient outcome accurately at the time of biopsy and initial diagnosis. Here we delineate the translation of a laboratory discovery through to the precision development of a clinically validated, novel prognostic biomarker assay (InformMDx™). This centres on determining transcript levels for phosphodiesterase-4D7 (PDE4D7), an enzyme that breaks down cyclic AMP, a signalling molecule intimately connected with proliferation and androgen receptor function. Quantifiable detection of PDE4D7 mRNA transcripts informs on the longitudinal outcome of post-surgical disease progression. The risk of post-surgical progression increases steeply for patients with very low ‘PDE4D7 scores’, while risk decreases markedly for those patients with very high ‘PDE4D7 scores’. Combining clinical risk variables, such as the Gleason or CAPRA (Cancer of the Prostate Risk Assessment) score, with the ‘PDE4D7 score’ further enhances the prognostic power of this personalized, precision assessment. Thus the ‘PDE4D7 score’ has the potential to define, more effectively, appropriate medical intervention/AS strategies for individual prostate cancer patients.

LncRNA PART1 modulates toll-like receptor pathways to influence cell proliferation and apoptosis in prostate cancer cells

We investigated thoroughly the effect of lncRNA PART1 on prostate cancer cells proliferation and apoptosis, through regulating toll-like receptor (TLR) pathways. LncRNA PART1 expression was also examined by quantitative real-time polymerase chain reactions (qRT-PCR) in human tissues and the cells lines LNCaP and PC3. After transfection with si-PART1 or control constructs, the cell viability was measured by MTS and colony formation assays. In addition, the apoptosis rate of the prostate cancer cells was validated by TUNEL staining. Relationships between lncRNA PART1 expression and TLR pathway genes were demonstrated by qRT-PCR and Western blotting. High levels of lncRNA PART1 expression were correlated with advanced cancer stage and predication of poor survival. LncRNA PART1 levels was increased in PCa cells treated with 5α-dihydrotestosterone (DHT), confirming PART1 was directly induced by androgen. Moreover, down-regulation of lncRNA PART1 inhibited prostate cancer cell proliferation and accelerated cell apoptosis. In addition, lncRNA PART1 induced downstream genes expression in TLR pathways including TLR3, TNFSF10 and CXCL13 to further influence prostate cancer cells, indicating its carcinogenesis on prostate cancer. LncRNA PART1 promoted cell proliferation ability and apoptosis via the inhibition of TLR pathways in prostate cancer. LncRNA PART1 could hence be considered as a new target in the treatment of prostate cancer.

Long noncoding RNA MALAT1 enhances the docetaxel resistance of prostate cancer cells via miR-145-5p-mediated regulation of AKAP12

Our present work was aimed to study on the regulatory role of MALAT1/miR-145-5p/AKAP12 axis on docetaxel (DTX) sensitivity of prostate cancer (PCa) cells. The microarray data (GSE33455) to identify differentially expressed lncRNAs and mRNAs in DTX-resistant PCa cell lines (DU-145-DTX and PC-3-DTX) was retrieved from the Gene Expression Omnibus (GEO) database. QRT-PCR analysis was performed to measure MALAT1 expression in DTX-sensitive and DTX-resistant tissues/cells. The human DTX-resistant cell lines DU145-PTX and PC3-DTX were established as in vitro cell models, and the expression of MALAT1, miR-145-5p and AKAP12 was manipulated in DTX-sensitive and DTX-resistant cells. Cell viability was examined using MTT assay and colony formation methods. Cell apoptosis was assessed by TUNEL staining. Cell migration and invasion was determined by scratch test (wound healing) and Transwell assay, respectively. Dual-luciferase assay was applied to analyse the target relationship between lncRNA MALAT1 and miR-145-5p, as well as between miR-145-5p and AKAP12. Tumour xenograft study was undertaken to confirm the correlation of MALAT1/miR-145-5p/AKAP12 axis and DTX sensitivity of PCa cells in vivo. In this study, we firstly notified that the MALAT1 expression levels were up-regulated in clinical DTX-resistant PCa samples. Overexpressed MALAT1 promoted cell proliferation, migration and invasion but decreased cell apoptosis rate of PCa cells in spite of DTX treatment. We identified miR-145-5p as a target of MALAT1. MiR-145-5p overexpression in PC3-DTX led to inhibited cell proliferation, migration and invasion as well as reduced chemoresistance to DTX, which was attenuated by MALAT1. Moreover, we determined that AKAP12 was a target of miR-145-5p, which significantly induced chemoresistance of PCa cells to DTX. Besides, it was proved that MALAT1 promoted tumour cell proliferation and enhanced DTX-chemoresistance in vivo. There was an lncRNA MALAT1/miR-145-5p/AKAP12 axis involved in DTX resistance of PCa cells and provided a new thought for PCa therapy.

Human PDE4D isoform composition is deregulated in primary prostate cancer and indicative for disease progression and development of distant metastases

Phosphodiesterase 4D7 was recently shown to be specifically over-expressed in localized prostate cancer, raising the question as to which regulatory mechanisms are involved and whether other isoforms of this gene family (PDE4D) are affected under the same conditions.We investigated PDE4D isoform composition in prostatic tissues using a total of seven independent expression datasets and also included data on DNA methylation, copy number and AR and ERG binding in PDE4D promoters to gain insight into their effect on PDE4D transcription.We show that expression of PDE4D isoforms is consistently altered in primary human prostate cancer compared to benign tissue, with PDE4D7 being up-regulated while PDE4D5 and PDE4D9 are down-regulated. Disease progression is marked by an overall down-regulation of long PDE4D isoforms, while short isoforms (PDE4D1/2) appear to be relatively unaffected. While these alterations seem to be independent of copy number alterations in the PDE4D locus and driven by AR and ERG binding, we also observed increased DNA methylation in the promoter region of PDE4D5, indicating a long lasting alteration of the isoform composition in prostate cancer tissues.We propose two independent metrics that may serve as diagnostic and prognostic markers for prostate disease: (PDE4D7 - PDE4D5) provides an effective means for distinguishing PCa from normal adjacent prostate, whereas PDE4D1/2 - (PDE4D5 + PDE4D7 + PDE4D9) offers strong prognostic potential to detect aggressive forms of PCa and is associated with metastasis free survival. Overall, our findings highlight the relevance of PDE4D as prostate cancer biomarker and potential drug target.

PART1 expression is associated with poor prognosis and tumor recurrence in stage I-III non-small cell lung cancer

Purpose: Long noncoding RNAs (lncRNAs) have been demonstrated as effective markers for cancer detection and prognosis prediction. The aim of this study was to determine whether tissue PART1 could be used as a biomarker for prognosis prediction of non-small cell lung cancer (NSCLC).

Methods: PART1 expression was detected in 208 cases of stage I-III NSCLC specimens and adjacent normal tissues. The Cox proportional-hazards regression model was used to analyze the association between PART1 expression and overall survival (OS) and disease-free survival (DFS) of the patients.

Results: It was found that the expression of PART1 was significantly up-regulated in 73.1% (152/208) stage I-III NSCLC specimens compared with adjacent normal tissues. High tissue PART1 expression was associated with shorter OS and could serve as an independent prognostic biomarker in stage I-III NSCLC patients (hazard ratio [HR] = 2.11, 95% CI = 1.18-3.78, P = 0.012). In addition, high tissue PART1 expression indicated poor DFS in stage I-III NSCLC patients (HR = 1.94, 95% CI: 1.37-2.76, P < 0.001).

Conclusions: PART1 may prove to be a promising biomarker for prediction of survival and tumor recurrence in stage I-III NSCLC.

The cAMP phosphodiesterase-4D7 (PDE4D7) is downregulated in androgen-independent prostate cancer cells and mediates proliferation by compartmentalising cAMP at the plasma membrane of VCaP prostate cancer cells

Background:

Isoforms of the PDE4 family of cAMP-specific phosphodiesterases (PDEs) are expressed in a cell type-dependent manner and contribute to underpinning the paradigm of intracellular cAMP signal compartmentalisation. Here we identify the differential regulation of the PDE4D7 isoform during prostate cancer progression and uncover a role in controlling prostate cancer cell proliferation.

Methods:

PDE4 transcripts from 19 prostate cancer cell lines and xenografts were quantified by qPCR. PDE4D7 expression was further investigated because of its significant downregulation between androgen-sensitive (AS) and androgen-insensitive (AI) samples. Western blot analysis, PDE activity assay, immunofluorescent staining and cAMP responsive FRET assays were used to investigate the sub-plasma membrane localisation of a population of PDE4D7 in VCaP (AS) and PC3 (AI) cell lines. Disruption of this localisation pattern using dominant-negative protein expression and siRNA knockdown showed that PDE4D7 acts in opposition to proliferative signalling as assessed by electrical impedance-based proliferation assays.

Results:

Here we identify the differential regulation of the PDE4D7 isoform during prostate cancer progression. PDE4D7 is highly expressed in AS cells and starkly downregulated in AI samples. The significance of this downregulation is underscored by our finding that PDE4D7 contributes a major fraction of cAMP degrading PDE activity tethered at the plasma membrane and that displacement of PDE4D7 from this compartment leads to an increase in the proliferation of prostate cancer cells. PDE4D7 mRNA expression is not, however, directly regulated by the androgen receptor signalling axis despite an overlapping genomic structure with the androgen responsive gene PART1. PDE4D7, which locates to the plasma membrane, acts to supress aberrant non-steroidal growth signals within the prostate or AS metastasis.

Conclusions:

PDE4D7 expression is significantly downregulated between AS and AI cell phenotypes. This change in expression potentially provides a novel androgen-independent biomarker and manipulation of its activity or its expression may provide therapeutic possibilities and insights into contributory aspects of the complex molecular pathology of prostate cancer.

D-PCa-2: a novel transcript highly overexpressed in human prostate and prostate cancer

Identification of genes selectively expressed in tumors or individual tissues is a crucial prerequisite for molecular diagnosis and treatment of cancer by addressing molecular targets. By screening an expression database, we identified the novel gene D-PCa-2 (Dresden prostate carcinoma 2), which is highly overexpressed in normal prostate tissue and prostate carcinoma (PCa). The corresponding transcript contained an open reading frame of 453 nucleotides encoding a putative protein of 150 amino acids. A large part of exon 8 of the D-PCa-2 gene shows strong similarity to the high-mobility-group nucleosomal binding protein 2 (HMGN2) cDNA. The highly specific transcription of the D-PCa-2 gene in normal and malignant prostate tissues and in a few additional tumors was demonstrated by using multiple tissue dot blot, cancer profiling dot blot and real-time PCR analyses. Examination of 18 pairs of tumorous and nontumorous prostate tissues from PCa patients by quantitative RT-PCR revealed D-PCa-2 transcripts in all specimens. The potential usefulness of D-PCa-2 as a sensitive marker for metastatic prostate carcinoma cells in lymph nodes was demonstrated by the detection of one LNCaP cell in 1 x 10(5) normal lymph node cells using real-time RT-PCR. Examination of 22 lymph nodes from PCa patients either containing metastatic prostate cancer cells or diagnosed as cancer-free was in full concordance with histopathologic diagnoses. These results validate D-PCa-2 as a transcript with high tissue specificity and with a potential application in the diagnosis of PCa.

Identification of an HLA-A*0201-restricted T-cell epitope derived from the prostate cancer-associated protein prostein

The development of T-cell-based immunotherapies of cancer largely depends on the availability of tumour-associated antigens capable of eliciting tumour-directed cytotoxic T-cell responses. In prostate cancer, the number of antigens defined as suitable targets of cytotoxic T lymphocytes (CTLs) is still limited. Recently, prostein was identified as a transmembrane protein that is highly restricted to prostate tissues. In our study, prostein transcripts were found to be abundant in both malignant and nonmalignant prostate tissue samples. To identify immunogenic CD8+ T-cell epitopes, human leucocyte antigen-A^*0201-binding peptides were selected from the amino-acid sequence of prostein and were used for the in vitro stimulation of CD8+ T lymphocytes. Specific CTLs were raised against the prostein-derived peptide CLAAGITYV that were capable of lysing prostate cancer cells, indicating that this peptide is naturally generated by tumour cells. Our data suggest that prostein is a suitable candidate to be included in a T-cell-based immunotherapy of prostate cancer.

Molecular markers to identify patients at risk for recurrence after primary treatment for prostate cancer

Accurate prognostication is a prerequisite for accurate therapeutics and management of prostate cancer because indolent tumors may require no intervention, whereas aggressive tumors lead to patient mortality. There is a critical need to define these subgroups of patients with prostate cancer differing in clinical outcome. Prognostic nomograms based on clinical data provide useful predictions of clinical states and outcomes, but they need further refinements to improve accuracy and universality. Genomic and proteomic analyses have provided many novel markers that may help define prognostic parameters based on the underlying biology of prostate cancer progression at the molecular level. These molecular markers are likely to augment traditional prognostic modalities by providing a set of molecularly defined and quantifiable variables. Encompassing the genome, transcriptome, and proteome of prostate cancer will likely provide "molecular signatures" that will bridge prognostication, prediction, and treatment in a single continuum.

Genistein and daidzein downregulate prostate androgen-regulated transcript-1 (PART-1) gene expression induced by dihydrotestosterone in human prostate LNCaP cancer cells

Epidemiologic investigations and laboratory studies suggest that bioactive soy phytochemical components may be used as an effective dietary regimen for prevention of prostate cancer. Studies designed to identify new genes that are responsive to androgens and are sensitive to the prevention of prostate cancer using soy bioactive components have become a research priority. In this study, we determined the effect of soy isoflavones on the expression of prostate androgen-regulated transcript 1 (PART-1), a newly discovered androgen-induced gene that may represent a novel androgen-dependent prostate cancer tumor marker. In an androgen-depleted cell culture system, 5alpha-dihydrotestosterone (DHT) induced expression of PART-1 transcript in androgen-sensitive LNCaP, but not in androgen-independent DU 145 or PC-3 human prostate cancer cells. The soy isoflavones genistein and daidzein dose-dependently inhibited DHT-induced expression of the PART-1 transcript. Genistein at 50 micro mol/L completely inhibited expression of the PART-1 transcript in LNCaP cells induced by DHT at 0.1 and 1.0 nmol/L. Daidzein was less potent than genistein, whereas glycitein at the same levels as genistein or daidzein did not inhibit DHT-induced PART-1 transcript expression. Our studies suggest that use of the PART-1 gene as a biomarker for evaluating the efficacy of soy isoflavones on androgen-dependent prostate cancer warrants further investigation.

Quantitative analysis of kallikrein 15 gene expression in prostate tissue

PURPOSE

The newly discovered human kallikrein 15 gene KLK15 has been shown in preliminary analysis to be associated with more aggressive types of prostate cancer. We quantitatively measured and compared gene expression of KLK15 in malignant and benign prostate tissues.

MATERIALS AND METHODS

Matched prostate tissue samples from the cancerous and noncancerous parts of the same prostates were obtained from 90 patients who underwent radical prostatectomy. Quantitative reverse transcriptase-polymerase chain reaction using SYBR Green I and the LightCycler system (Roche Applied Science, Mannheim, Germany) was performed. Associations of KLK15 expression with clinicopathological parameters were analyzed.

RESULTS

KLK15 over expression in cancerous versus noncancerous tissue was found in 76 of the 90 patient samples (84.4%, p <0.001). The ratio of cancerous-to-noncancerous KLK15 expression tended to be higher in patients with stage pT3/4 versus pT2 tumors (p = 0.1). KLK15 expression tended to be higher in grade 3 than in grade 2 tumors and in Gleason score 7 or greater than in Gleason score less than 7 tumors (p = 0.18 and 0.23, respectively). A 1.7 cutoff at the 40th percentile provided a significant difference in stages pT2 and pT3/4 tumors (p = 0.029).

CONCLUSIONS

On quantitative real-time polymerase chain reaction KLK15 expression was significantly higher in cancerous than in noncancerous tissue. Up-regulation of the KLK15 gene in advanced and more aggressive tumors may indicate a possible role for KLK15 protein as future serum marker for prostate cancer and for distinguishing tumor aggressiveness.

Identifying immunotherapeutic targets for prostate carcinoma through the analysis of gene expression profiles

Carcinoma of the prostate represents one of the most frequently diagnosed cancers in men. If detected at an early stage, prostate cancer is highly treatable. However, cancers identified at a late stage are rarely cured with contemporary medical therapies. Early detection strategies presently center on the identification of prostate-specific proteins in the serum, and emerging therapeutics have utilized genes and proteins with prostate-restricted expression for tissue-selective immunological regimens incorporating vaccines, dendritic cell therapy, gene therapy, and antibody-based cell targeting. In order to develop improved therapeutic procedures, efforts have been directed toward the identification of genes exhibiting prostate-restricted expression profiles, or altered expression levels in neoplastic cells relative to their normal counterparts. Comprehensive expression profiling approaches such as the analysis of oligonucleotide- or complementary DNA (cDNA)-microarrays have greatly enhanced these efforts. Genes and their cognate proteins identified using such methods offer additional diagnostic and therapeutic targets that may aid in the understanding and treatment of prostate carcinoma.