Inhibition of PAX2 expression results in alternate cell death pathways in prostate cancer cells differing in p53 status

Expression of the human antimicrobial peptide β-defensin-1 is repressed by the EGFR-ERK-MYC axis in colonic epithelial cells

The human β-defensin-1 (HBD1) is an antimicrobial peptide constitutively expressed by epithelial cells at mucosal surfaces. In addition to its microbicidal properties, the loss of HBD1 expression in several cancers suggests that it may also have an anti-tumor activity. Here, we investigated the link between HBD1 expression and cancer signaling pathways in the human colon cancer cell lines TC7 and HT-29, and in normal human colonic primary cells, using a mini-gut organoid model. Using available datasets from patient cohorts, we found that HBD1 transcription is decreased in colorectal cancer. We demonstrated that inhibiting the Epidermal Growth Factor Receptor (EGFR) increased HBD1 expression, whereas activating EGFR repressed HBD1 expression, through the MEKK1/2-ERK1/2 pathway that ultimately regulates MYC. We finally present evidences supporting a role of MYC, together with the MIZ1 coregulator, in HBD1 regulation. Our work uncovers the role and deciphers the function of the EGFR-ERK-MYC axis as a repressor of HBD1 expression and contributes to the understanding of HBD1 suppression observed in colorectal cancer.

Paired box 2 promotes progression of endometrial cancer via regulating cell cycle pathway

Background: Human paired box 2 (PAX2) plays a key role in cell fate, early patterning and organogenesis.

Methods: We investigated the function of PAX2 on the biological behavior of endometrial cancer in vitro and in vivo and to explore the regulation mechanism, stable knocking-down and over-expression PAX2 endometrial cancer cell lines were established. CCK-8 and transwell assays were applied to determine proliferation, invasion and migration ability. Cell cycle distribution was analyzed by flow cytometry. Affymetrix GeneChip® human Exon 1.0 ST arrays was used to screen the downstream target genes of PAX2.

Results: PAX2 significantly enhanced proliferation and invasiveness. In addition, PAX2 influenced the expression of cyclin-dependent kinase 1(CDK1), which play pivotal roles in cell cycle pathway. When CDK1 was knocked down, and the cell proliferation promotion role of PAX2 was attenuated dramatically to a level comparable with the control groups.

Conclusions: PAX2, though influencing the expression of CDK1, promotes the proliferation, enhances the mobility of endometrial cancer cells, thus exerts an important role in the carcinogenesis of endometrial cancer. PAX2 may be a potential therapeutic target for endometrial cancer.

CP-31398 inhibits the progression of cervical cancer through reversing the epithelial mesenchymal transition via the downregulation of PAX2s

CP-31398, a styrylquinazoline, emerges from a screen for therapeutic agents that restore the wild-type DNA-binding conformation of mutant p53 to suppress tumors in vivo, but its effects on cervical cancer (CC) remain unknown. Hence, this study aimed to explore the effects CP-31398 has on the CC cells and to investigate whether it is associated with paired box 2 (PAX2) expression. CC cells were treated with different concentrations of CP-31398 (1, 2, 4, 6, 8, and 10 μg/ml) to determine the optimum concentration using fluorometric microculture cytotoxicity assay. After constructing the sh-PAX2 vector, CC cells were transfected with sh-PAX2 or treated with CP-31398. The effects of CP-31398 or PAX2 silencing on CC cell proliferation, apoptosis, invasion, and migration were evaluated. Epithelial mesenchymal transition (EMT)-related genes such as E-cadherin, vimentin, N-cadherin, snail, and twist in CC cells were detected. Tumor formation experiment in nude mice was performed to observe tumor growth. The optimum concentration of CP-31398 was 2 μg/ml. PAX2 was overexpressed in CC cells. CC cells treated with CP-31398 or treated with sh-PAX2 inhibited proliferation, invasion, and migration but promoted apoptosis with decreased PAX2 expression. The EMT process in CC cells was also reversed after treatment with CP-31398 or sh-PAX2. Moreover, the tumor formation experiment in nude mice revealed the inhibitory activity of CP-31398 in CC tumor in nude mice by suppressing PAX2. Our results provide evidence that CP-31398 could inhibit EMT and promote apoptosis of CC cells to curb CC tumor growth by downregulating PAX2.

Ruguo key genes and tumor driving factors identification of bladder cancer based on the RNA-seq profile

Aim

This study aimed to select several signature genes associated with bladder cancer, thus to investigate the possible mechanism in bladder cancer.

Methods

The mRNA expression profile data of GSE31614, including ten bladder tissues and ten control samples, was downloaded from the Gene Expression Omnibus. The differentially expressed genes (DEGs) in bladder cancer samples compared with the control samples were screened using the Student’s t-test method. Functional analysis for the DEGs was analyzed using the Database for Annotation, Visualization, and Integrated Discovery from the Gene Ontology database, followed by the transcription function annotation of DEGs from Tumor-Associated Gene database. Motifs of genes that had transcription functions in promoter region were analyzed using the Seqpos.

Results

A total of 1,571 upregulated and 1,507 downregulated DEGs in the bladder cancer samples were screened. ELF3 and MYBL2 involved in cell cycle and DNA replication were tumor suppressors. MEG3, APEX1, and EZH2 were related with the cell epigenetic regulation in bladder cancer. Moreover, HOXB9 and EN1 that have their own motif were the transcription factors.

Conclusion

Our study has identified several key genes involved in bladder cancer. ELF3 and MYBL2 are tumor suppressers, HOXB9 and EN1 are the main regulators, while MEG3, APEX1, and EZH2 are driving factors for bladder cancer progression.

EN2 in Prostate Cancer

Despite extensive efforts to identify a clinically useful diagnostic biomarker in prostate cancer, no new test has been approved by regulatory authorities. As a result, this unmet need has shifted to biomarkers that additionally indicate presence or absence of "significant" disease. EN2 is a homeodomain-containing transcription factor secreted by prostate cancer into the urine and can be detected by enzyme-linked immunoassay. EN2 may be an ideal biomarker because normal prostate tissue and benign prostatic hypertrophic cells do not secrete EN2. This review discusses the enormous potential of EN2 to address this unmet need and provide the urologist with a simple, inexpensive, and reliable prostate cancer biomarker.

EN2: a novel prostate cancer biomarker

Extensive efforts to identify a clinically useful biomarker for the diagnosis of prostate cancer have resulted in important insights into the biology of the disease, but no new test has been approved by regulatory authorities. The unmet need has also shifted to identifying biomarkers that not only diagnose prostate cancer but also indicate whether the patient has 'significant' disease. EN2 is a homeobox-containing transcription factor secreted specifically by prostate cancers into urine, where it can be detected by a simple ELISA assay. A number of studies have demonstrated the enormous potential of EN2 to address this unmet need and provide the urologist with a simple, cheap and efficient prostate cancer biomarker.

MicroRNA-181b expression in prostate cancer tissues and its influence on the biological behavior of the prostate cancer cell line PC-3

We examined microRNA-181b (miRNA) expression in prostate cancer tissues and its effect on the prostate cancer cell line PC-3. Tissues from 27 cases of prostate cancer and 30 samples of normal human prostate were collected by surgical removal. Total miRNA was extracted, and the relative expression of miR-181b was quantified using RT-PCR. miR-181b ASO was transfected into prostate cancer PC-3 cells. miR-181b expression in transfected and non-transfected cells was measured using RT-PCR. Changes in cell apoptosis were measured using flow cytometry. MTT and cell growth curve methods were used to assess the influence of miR-181b expression on cell proliferation. The changes in cell invasive ability in vitro were detected using the Transwell chamber method. miR-181b was up-regulated in the prostate cancer tissues compared with the normal prostate samples. It was down-regulated after miR-181b ASO transfection into the prostate cancer PC-3 cells. Down-regulation of miR-181b in the PC-3 cell induced apoptosis, inhibited proliferation, and depressed invasion of PC-3 cells in vitro. As miR-181b is over-expressed in prostate cancer, its down-regulation could have potential as gene therapy for prostate cancer by inducing apoptosis, inhibiting proliferation and depressing invasion by cancer cells.

PAX2 protein induces expression of cyclin D1 through activating AP-1 protein and promotes proliferation of colon cancer cells

Paired box (PAX) 2, a transcription factor, plays a critical role in embryogenesis. When aberrantly expressed in adult tissues, it generally exhibits oncogenic properties. However, the underlying mechanisms remain unclear. We reported previously that the expression of PAX2 was up-regulated in human colon cancers. However, the role of PAX2 in colon cancer cells has yet to be determined. The aim of this study is to determine the function of PAX2 in colon cancer cells and to investigate the possible mechanisms underlain. We find that knockdown of PAX2 inhibits proliferation and xenograft growth of colon cancer cells. Inhibition of PAX2 results in a decreased expression of cyclin D1. Expression of cyclin D1 is found increased in human primary colon malignant tumors, and its expression is associated with that of PAX2. These data indicate that PAX2 is a positive regulator of expression of cyclin D1. We find that knockdown of PAX2 inhibits the activity of AP-1, a transcription factor that induces cyclin D1 expression, implying that PAX2 induces cyclin D1 through AP-1. PAX2 has little effect on expression of AP-1 members including c-Jun, c-Fos, and JunB. Our data show that PAX2 prevents JunB from binding c-Jun and enhances phosphorylation of c-Jun, which may elevate the activity of AP-1. Taken together, these results suggest that PAX2 promotes proliferation of colon cancer cells through AP-1.

Characterization of a New Monoclonal Antibody Against PAX5/BASP in 1525 Paraffin-embedded Human and Animal Tissue Samples

INTRODUCTION

We describe the newly generated DAK-PAX5 monoclonal antibody raised against a fixation-resistant epitope of the human PAX5/BSAP molecule.

MATERIALS AND METHODS

Following Western-blot, absorption, and chess-board titration tests, and optimization of antigen-retrieval and detection methods, DAK-Pax5 was used in parallel with a reference antibody (clone 24) on tissue micro-arrays (TMAs) constructed from normal human and animal tissues and from hematologic and nonhematologic human malignancies. Such TMAs were also tested with an anti-PAX2 antibody.

RESULTS

DAK-Pax5 reacted with normal human and animal B-cells and with 460/473 B-cell non-Hodgkin lymphomas (B-NHLs). All plasmacytomas/plasmablastic tumors (n=13) and T/NK-cell neoplasms (n=264) turned out consistently negative as did acute myelogenous leukaemias (n=19) except 2 carrying t(8;21). Positivity was found in 6/6 and 155/169 lymphocyte predominant and classical HLs, respectively, although the staining intensity varied through cases. Among 521 nonhematologic malignancies, DAK-Pax5 reacted with 22/399 carcinomas (4/11 neuroendocrine, 2/4 Merkel-cell, 4/21 prostatic, 1/11 urothelial, 1/26 renal, 2/12 cervical squamous-cell, 3/13 ovarian, and 5/75 colonic). When compared with clone 24, DAK-Pax5 produced a stronger positivity in most if not all B-NHLs and HLs. No cross-reactivity with the anti-PAX2 antibody was recorded.

DISCUSSION

DAK-Pax5 represents a new reliable tool for diagnostics and research.

The PAX258 gene subfamily: a comparative perspective

Whole genome duplication events are thought to have substantially contributed to organismal complexity, largely via divergent transcriptional regulation. Members of the vertebrate PAX2, PAX5 and PAX8 gene subfamily derived from an ancient class of paired box genes and arose from such whole genome duplication events. These genes are critical in establishing the midbrain-hindbrain boundary, specifying interneuron populations and for eye, ear and kidney development. Also PAX2 has adopted a unique role in pancreas development, whilst PAX5 is essential for early B-cell differentiation. The contribution of PAX258 genes to their collective role has diverged across paralogues and the animal lineages, resulting in a complex wealth of literature. It is now timely to provide a comprehensive comparative overview of these genes and their ancient and divergent roles. We also discuss their fundamental place within gene regulatory networks and the likely influence of cis-regulatory elements over their differential roles during early animal development.

Potential therapeutic application of host defense peptides

Host defense peptides (HDPs) are relatively small, mostly cationic, amphipathic, and of variable length, sequence, and structure. The majority of these peptides exhibit broad-spectrum antimicrobial activity and often activity against viruses and some cancer cell lines. In addition, HDPs also provide a range of immunomodulatory activities related to innate immunity defense, inflammation, and wound healing. The development of these multi-faceted molecules and their bioactivities into clinically important therapeutics is being pursued using a number of different approaches. Here we review the role of HDPs in nature and application of this role to the development of novel therapeutics.

Angiotensin II up-regulates PAX2 oncogene expression and activity in prostate cancer via the angiotensin II type I receptor

BACKGROUND

Paired homeobox 2 gene (PAX2) is a transcriptional regulator, aberrantly expressed in prostate cancer cells and its down-regulation promotes cell death in these cells. The molecular mechanisms of tumor progression by PAX2 over-expression are still unclear. However, it has been reported that angiotensin-II (A-II) induces cell growth in prostate cancer via A-II type 1 receptor (AT1R) and is mediated by the phosphorylation of mitogen activated protein kinase (MAPK) as well as signal transducer and activator of transcription 3 (STAT3).

METHODS

Here we have demonstrated that A-II up-regulates PAX2 expression in prostate epithelial cells and prostate cancer cell lines resulting in increased cell growth. Furthermore, AT1R receptor antagonist losartan was shown to inhibit A-II induced PAX2 expression in prostate cancer. Moreover, analysis using pharmacological inhibitors against MEK1/2, ERK1/2, JAK-II, and phospho-STAT3 demonstrated that AT1R-mediated stimulatory effect of A-II on PAX2 expression was regulated in part by the phosphorylation of ERK1/2, JAK II, and STAT3 pathways. In addition, we have showed that down-regulation of PAX2 by an AT1R antagonist as well as JAK-II and STAT3 inhibitors suppress prostate cancer cell growth.

RESULTS

Collectively, these findings show for the first time that the renin-angiotensin system (RAS) may promote prostate tumorigenesis via up-regulation of PAX2 expression.

CONCLUSIONS

Therefore, PAX2 may be a novel therapeutic target for the treatment of carcinomas such as prostate cancer via the down-regulation of its expression by targeting the AT1R signaling pathways.

PAX2 oncogene negatively regulates the expression of the host defense peptide human beta defensin-1 in prostate cancer

Human beta defensin-1 (hBD1) is a component of the immune system which links the innate and adaptive immune responses. We have demonstrated that hBD1 induces rapid cytolysis of prostate cancer cells and that it may also possess tumor suppressive abilities. In addition, there is a high frequency of cancer-specific loss of hBD1 expression which further suggests its potential role in tumor progression. However, the factors responsible for the loss of hBD1 expression are not known. PAX2, a transcriptional regulator normally expressed during early development, has been implicated as an oncogene in carcinomas of the kidney, prostate, breast and ovary. It is known that expression of PAX2 in these tumor cells mediates the evasion of cell death through the suppression of cell death pathways involving the p53 tumor suppressor. However, we have demonstrated that knock-down of PAX2 expression results in cell death independent of p53 status, thus suggesting that additional cell death pathways are negatively regulated by PAX2. Here we describe a novel pathway in which PAX2 represses hBD1 expression through binding of the PAX2 homeodomain to the hBD1 promoter. Furthermore, knock-down of PAX2 expression results in the re-expression of hBD1, and subsequently prostate cancer cell death. These findings are the first to demonstrate that the PAX2 oncogene suppresses hBD1 expression in cancer and further implicate PAX2 as a novel therapeutic target for prostate cancer treatment.

Molecular markers in prostate cancer. Part I: predicting lethality

Assessing the lethality of 'early,' potentially organ-confined prostate cancer (PCa) is one of the central controversies in modern-day urological clinical practice. Such cases are often considered for radical 'curative' treatment, although active surveillance may be equally appropriate for many men. Moreover, the balance between judicious intervention and overtreatment can be difficult to judge. The patient's age, comorbidities, family history and philosophy of self-health care can be weighed against clinical features such as the palpability of disease, the number and percentage of biopsy cores involved with the disease, histological grade, presenting prostate-specific antigen (PSA) and possible previous PSA kinetics. For many years, scientists and physicians have sought additional molecular factors that may be predictive for disease stage, progression and lethality. Usually, claims for a 'new' unique marker fall short of true clinical value. More often than not, such molecular markers are useful only in multivariate models. This review summarizes relevant molecular markers and models reported up to and including 2008.

Pax genes in embryogenesis and oncogenesis

The paired box genes are a family of nine developmental control genes, which in human beings (PAX) and mice (Pax) encode nuclear transcription factors. The temporal and spatial expressions of these highly conserved genes are tightly regulated during foetal development including organogenesis. PAY/Paxgenes are switched off during the terminal differentiation of most structures. Specific mutations within a number of PAX/Pax genes lead to developmental abnormalities in both human beings and mice. Mutation in PAX3 causes Waardenburg syndrome, and craniofacial-deafness-hand syndrome. The Splotch phenotype in mouse exhibits defects in neural crest derivatives such as, pigment cells, sympathetic ganglia and cardiac neural crest-derived structures. The PAX family also plays key roles in several human malignancies. In particular, PAX3 is involved in rhabdomyosarcoma and tumours of neural crest origin, including melanoma and neuroblastoma. This review critically evaluates the roles of PAX/Pax in oncogenesis. It especially highlights recent advances in knowledge of how their genetic alterations directly interfere in the transcriptional networks that regulate cell differentiation, proliferation, migration and survival and may contribute to oncogenesis.

In vivo validation of PAX2 as a target for renal cancer therapy

PAX genes are frequently overexpressed in human cancer tissue and appear to contribute to the tumor phenotype, suggesting that they may be potential targets for cancer therapy. In particular, aberrant PAX2 expression has been reported in a high proportion of primary tumors, including the majority of renal cell carcinomas (RCC). We recently demonstrated that PAX2 suppresses cisplatin-induced apoptosis in cultured RCC cells. We hypothesized that silencing of PAX2 expression might partially overcome the notorious resistance of renal cell carcinomas to chemotherapy in vivo. In this report, we show that a PAX2 shRNA successfully knocks down PAX2 mRNA and protein levels in an RCC cell line (ACHN). ACHN cells stably transfected with shRNAs targeted against the PAX2 homeodomain are 3-6-fold more susceptible to cisplatin-induced caspase-3 activation than control ACHN cells line. Furthermore, growth of subcutaneous ACHN/shPAX2 xenografts in nude mice is significantly more responsive to cisplatin therapy than control ACHN cell tumors. Our observations validate PAX2 as a potential therapeutic gene target in renal cancer and suggest that adjunctive PAX2 knockdown may enhance the efficacy of other chemotherapeutic agents.

Functional analysis of the host defense peptide Human Beta Defensin-1: new insight into its potential role in cancer

Although it is known that innate immunity is key for protecting the body against foreign agents such as bacteria, little is known about elements of the innate immune system that have anti-tumor activity. Human Beta Defensin-1 (hBD-1), an important component of the innate immune response, is lost at high frequencies in malignant prostatic tissue, while high levels of expression are maintained in adjacent benign regions. In prostate carcinoma, frequent genetic alterations occur in the 8p22-23 region and several studies indicate there may be multiple tumor suppressor genes present within this region. The high incidence of loss of hBD-1 expression in prostate cancer, along with its chromosomal location of 8p23.2, raised the possibility that it may play a role in tumor suppression. To gain insight as to its function in prostate cancer, hBD-1 was cloned and ectopically expressed in four prostate cancer cell lines. Induction of hBD-1 expression resulted in a decrease in cellular growth in DU145 and PC3 cells. However, hBD-1 has no effect on the growth of androgen receptor (AR) positive LNCaP prostate cancer cells, but was again growth suppressive to PC3 cells with ectopic AR expression (PC3/AR+). hBD-1 also caused rapid induction of cytolysis and caspase-mediated apoptosis in DU145 and PC3 prostate cancer cells. Although the regulation of hBD-1 was not addressed in this study, our preliminary data demonstrated that the pathways involved may include cMYC and PAX2. Data presented here are the first to provide evidence of its potential role in prostate cancer cell death.