PRDI-BF1 And RIZ Research Articles

Therapeutic siRNA targeting the cancer cell stemness regulator PRDI-BF1 and RIZ domain zinc finger protein 14.

PRDI-BF1 and RIZ (PR) domain zinc finger protein 14 (PRDM14), first reported in 2007 to be overexpressed in breast cancer, plays an important role in breast cancer proliferation. Subsequent studies reported that PRDM14 is expressed in embryonic stem cells, primordial germ cells, and various cancers. PRDM14 was reported to confer stemness properties to cancer cells. These properties induce cancer initiation, cancer progression, therapeutic resistance, distant metastasis, and recurrence in refractory tumors. Therefore, PRDM14 may be an ideal therapeutic target for various types of tumors. Silencing PRDM14 expression using PRDM14-specific siRNA delivered through an innovative intravenous drug delivery system reduced the size of inoculated tumors, incidence of distant metastases, and increased overall survival in nude mice without causing adverse effects. Therapeutic siRNA targeting PRDM14 is now being evaluated in a human phase I clinical trial for patients with refractory breast cancer, including triple-negative breast cancer.

PRDM5 suppresses oesophageal squamous carcinoma cells and modulates 14-3-3zeta/Akt signalling pathway.

Dysregulation of PR (PRDI-BF1 and RIZ) domain protein 5 (PRDM5) expression has been shown to be associated with the progression of many malignancies. Nevertheless, the role and underlying mechanism of PRDM5 in oesophageal squamous cell carcinoma (ESCC) remain elusive. qRT-PCR was performed to analyze PRDM5 mRNA expression, and western blot was used to determine protein expression of PRDM5, MMP-2, MMP-9, 14-3-3zeta, pan-Akt and phosphorylated Akt expression. CCK-8 staining was employed to evaluate cell proliferation, while wound scratch assay and Transwell assay were carried out to detect cell migration. A tumour xenograft model of ESCC was also established to validate the effect of PRDM5. PRDM5 expression was downregulated in ESCC tissues and positively correlated with the overall survival of ESCC patients. Silencing PRDM5 expression promoted cell proliferation in ESCC cells, while overexpressing PRDM5 inhibited cell proliferation. Moreover, the migratory abilities of ESCC cells were promoted by PRDM5 knockdown but were attenuated by PRDM5 overexpression. Importantly, 14-3-3zeta expression, along with the phosphorylation of Akt, was suppressed by PRDM5 in ESCC cells. In the established tumour xenograft model, PRDM5 regulated ESCC tumour growth as well as the expression of 14-3-3zeta and phosphorylation of Akt protein. In conclusion, PRDM5suppresses ESCC cell proliferation and migration and negatively regulates 14-3-3zeta/Akt signalling pathway in vitro and in vivo.

Silencing PRDM14 via Oligonucleotide Therapeutics Suppresses Tumorigenicity and Metastasis of Breast Cancer.

The PRDI-BF1 and RIZ (PR) domain zinc finger protein 14 (PRDM14) is upregulated in approximately 60% of breast cancers, some of which exhibit gene amplification. In contrast, PRDM14 is not expressed in normal, and differentiated tissues. PRDM14+ breast cancer cells are resistant to chemotherapy drugs, are tumorigenic, and metastasize to the lungs. It is commonly assumed that genes that are overexpressed in cancers, such as PRDM14, are effective targets for new therapies that specifically abrogate the expression of these genes. RNA interference of PRDM14, a gene expressed by breast cancer cells, reduced the size of tumors and lung metastases in nude mice. In this chapter, we introduce the concept and methods to develop and apply systematically injected small interfering RNA therapy for breast cancer models in vivo.

Knockdown of lncRNA BDNF-AS suppresses neuronal cell apoptosis via downregulating miR-130b-5p target gene PRDM5 in acute spinal cord injury

ABSTRACTObjective: The present study was designed to investigate the molecular mechanism and biological roles of lncRNA brain-derived neurotrophic factor antisense (lncRNA BDNF-AS) in acute spinal cord injury (ASCI). Methods: The rat model of ASCI and hypoxic cellular model were established to detect the expression of BDNF-AS, miR-130b-5p, PR (PRDI-BF1 and RIZ) domain protein 5 (PRDM5) and cleaved caspase 3 (c-caspase 3) using qRT-PCR and western blot. Basso, Beattie and Bresnahan (BBB) score was carried out to assess neurological function. Flow cytometry was used to determine the apoptosis of neuronal cells. The association among BDNF-AS, miR-130b-5p and PRDM5 were disclosed by RNA immunoprecipitation (RIP) assay, RNA pull-down assay and dual-luciferase reporter assay. Results: BDNF-AS, PRDM5 and c-caspase 3 expression were significantly upregulated, while miR-130b-5p was suppressed in the ASCI group and neuronal cells following hypoxia treatment. BDNF-AS knockdown inhibited neuronal cell apoptosis. Further studies indicated that BDNF-AS functioned as a competing endogenous RNA (ceRNA) by sponging miR-130b-5p in neuronal cells. Further investigations demonstrated that PRDM5 was a target of miR-130b-5p and BDNF-AS knockdown exerted anti-apoptotic effects via miR-130b-5p/PRDM5 axis. Conclusion: The lncRNA BDNF-AS/miR-130b-5p/PRDM5 axis might be a promising therapeutic target for ASCI.

Abstract 3959: PRDM14 silencing by siRNA combined with an innovative nanoparticle reduced breast tumor formation and metastasis in vivo

Abstract Triple negative breast cancer (hereafter TNBC) exhibits resistant to chemotherapy and radiotherapy, and develops distant metastases. Conventional treatments have had little impacts on TNBC. PRDI-BF1 and RIZ (PR) domain zinc finger protein 14 (PRDM14) is specifically expressed in embryonic stem cells (ESC) and primordial germ cells (PgC), and is required for the maintenance of ESC pluripotency and early differentiation in PgC. There is no expression of PRDM14 in the non-cancerous tissues, however PRDM14 is expressed in ~50% of TNBC, approximately. PRDM14 conferred the ability of resistance to chemotherapy, tumorigenicity and metastasis, in other words ‘cancer stemness', on cancer cells (Taniguchi H, et al. Oncotarget 2017). PRDM14 was localized in nucleus, then we planned to develop an oligonucleotide therapeutics against PRDM14. Our therapeutic methods are built on clinical application of basic science and technologies. #1. Methods of design the siRNA sequences with higher selectivity to its target and elimination off-target effects. #2. RNA-DNA chimera modification of small interfering RNA (chimera siRNA) exhibited stability in the bloodstream and low immunogenicity. #3. A polyion complex (PIC) nanocarrier exhibited high retention in blood, and accumulated siRNA in targeted cancer tissues, not in liver and spleen, due to the enhanced permeability and retention effect compared with typical nanocarriers, such as Lipid Nanoparticle. Mice were orthotopically grafted with PRDM14+ HCC1937 (TNBC) cells. We also injected PRDM14+ MDA-MB-231 (TNBC) cells into mice via the tail vein for lung metastasis. PRDM14-specific chimera siRNA (1mg/kg) mixed with a PIC nanocarrier (N/P ratio = 5) was injected into mice tail vain 3 times a week for a month, after the HCC1937 tumor reached over 100mm3. This treatment caused 50.3% reduction of mean relative tumor volume, 98% reduction by synergistic effect with docetaxel (3.0mg/kg), and almost no lung metastatic lesions of MDA-MB-231 cells without any adverse effects. GLP toxicology studies of PRDM14-specific chimera siRNA mixed with a PIC nanocarrier in female rats and monkeys showed no severe toxicity at 0.2, 1, or 2 mg/kg/day, twice a week for 4 weeks. Concomitant PK/TK studies revealed much higher exposure for PIC formulated siRNA than that for naked siRNA. Cmax was14900 ± 3200ng/ml, and AUC0-24h was 3730 ± 790 ng·h/mL for PIC formulated siRNA at 1mg/kg at day25.Naked siRNA was only detectable in plasma of animals for 2 h after administration of 1 mg/kg. We plan to submit an academic IND for First time in a human Phase I clinical trial for TNBC after finishing further extensive formulation works in 2019. Citation Format: Hiroaki Taniguchi, Chiharu Moriya, Shiro Akinaga, Kozo Imai, Kazunori Kataoka. PRDM14 silencing by siRNA combined with an innovative nanoparticle reduced breast tumor formation and metastasis in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3959.

PRDM14 is expressed in germ cell tumors with constitutive overexpression altering human germline differentiation and proliferation

Germ cell tumors (GCTs) are a heterogeneous group of tumors occurring in gonadal and extragonadal locations. GCTs are hypothesized to arise from primordial germ cells (PGCs), which fail to differentiate. One recently identified susceptibility loci for human GCT is PR (PRDI-BF1 and RIZ) domain proteins 14 (PRDM14). PRDM14 is expressed in early primate PGCs and is repressed as PGCs differentiate. To examine PRDM14 in human GCTs we profiled human GCT cell lines and patient samples and discovered that PRDM14 is expressed in embryonal carcinoma cell lines, embryonal carcinomas, seminomas, intracranial germinomas and yolk sac tumors, but is not expressed in teratomas. To model constitutive overexpression in human PGCs, we generated PGC-like cells (PGCLCs) from human pluripotent stem cells (PSCs) and discovered that elevated expression of PRDM14 does not block early PGC formation. Instead, we show that elevated PRDM14 in PGCLCs causes proliferation and differentiation defects in the germline.

PRDM5 Expression and Essential Role After Acute Spinal Cord Injury in Adult Rat.

PR (PRDI-BF1 and RIZ) domain proteins (PRDM) are a subfamily of the kruppel-like zinc finger gene products that modulate cellular processes such as differentiation, cell growth and apoptosis. PRDM5 is a recently identified family member that functions as a transcriptional repressor and behaves as a putative tumor suppressor in different types of cancer. However, the expression and function of PRDM5 in spinal cord injury (SCI) are still unknown. In the present study, we have performed an acute SCI model in adult rats and investigated the dynamic changes of PRDM5 expression in the spinal cord. We found that PRDM5 protein levels gradually increased, reaching a peak at day 5 and then gradually declined to a normal level at day 14 after SCI with Western blot analysis. Double immunofluorescence staining showed that PRDM5 immunoreactivity was found in neurons, astrocytes and microglia. However, the expression of PRDM5 was increased predominantly in neurons. Additionally, colocalization of PRDM5/active caspase-3 was been respectively detected in neurons. In vitro, we found that depletion of PRDM5 by short interfering RNA, obviously decreases neuronal apoptosis. In summary, this is the first description of PRDM5 expression in SCI. Our results suggested that PRDM5 might play crucial roles in CNS pathophysiology after SCI and this research will provide new drug targets for clinical treatment of SCI.

Deletion of Prdm8 impairs development of upper-layer neocortical neurons.

Upper-layer (UL) neocortical neurons are the most prominent distinguishing features of the mammalian neocortex compared with those of the avian dorsal cortex and are vastly expanded in primates. However, little is known about the identities of the genes that control the specification of UL neurons. Here, we found that Prdm8, a member of the PR (PRDI-BF1 and RIZ homology) domain protein family, was specifically expressed in the postnatal UL neocortex, particular those in late-born RORß-positive layer IV neurons. We generated homozygous Prdm8 knockout (Prdm8 KO) mice and found that the deletion of Prdm8 causes growth retardation and a reduced brain weight, although the brain weight-to-body weight ratio is unchanged at postnatal day 8 (P8). Immunohistochemistry showed that the relative UL thickness, but not the thickness of the deep layer (DL), was significantly reduced in Prdm8 KO mice compared with wild-type (WT) mice. In addition, we found that a number of late-born Brn2-positive UL neurons were significantly decreased in Prdm8 KO mice. To identify genes regulated by Prdm8 during neocortical development, we compared expression profiling analysis in Prdm8 KO and WT mice, and identified some candidate genes. These results suggest that the proper expression of Prdm8 is required for the normal development and construction of UL neurons in the mammalian neocortex.

High expression of PRDM14 correlates with cell differentiation and is a novel prognostic marker in resected non-small cell lung cancer

PR (PRDI-BF1 and RIZ) domain containing proteins (PRDM) have been indicated to play important roles in several human cancers. The objectives of this study were to determine the frequency and prognostic significance of PRDM1 and PRDM14 expression in a cohort of surgically resected non-small cell lung cancer (NSCLC) patients. Immunohistochemistry and Western blotting was used to detect the expression status of PRDM1 in primary tumors and PRDM14 for both primary lung cancers and matched lymph node metastases. Univariate and multivariate analysis were performed to determine the association between PRDM expression and prognosis. PRDM1 expression was observed in all NSCLC patients' tumor samples. PRDM14 was found to be increased expression in 35.65 % cases (46/129) for primary tumors and 39.68 % cases (25/63) for paired metastatic lymph nodes. Increased expression of PRDM14 correlated with differentiation of tumor cells significantly (P = 0.008). Western blotting analysis verified that PRDM14 associated with cell differentiation in NSCLC. The overall survival rates of patients with high PRDM14 expression and low PRDM14 expression were 41.30 and 65.06 %, respectively (hazard ratio: 3.051, 95 % CI: 1.752, 5.312, P < 0.0001). The progression-free survival rates were 34.78 % for patients in the high expression group and 59.03 % for patients in the low OLC1 expression group (hazard ratio: 2.775, 95 % CI: 1.648, 4.675, P < 0.0001). Thus, our study showed that increased expression of PRDM14 correlated with cell differentiation of NSCLC cells. PRDM14 was a potential biomarker for predicting unfavorable prognosis in NSCLC.

DNA methylation and carcinogenesis of PRDM5 in cervical cancer

PR (PRDI-BF1 and RIZ) domain proteins (PRDM) are a subfamily of the kruppel-like zinc finger gene products and play key roles during cell differentiation and malignant transformation. PRDM5 (PR domain containing 5 PFM2) is a new PR-domain-containing gene. The purpose of the present study was to examine the expression of PRDM5 and evaluate its carcinogenesis in cervical cancer. The relationship between DNA methylation and transcriptional silencing of PRDM5 was investigated in cervical cancer. PRDM5 expression was examined in cervical cancer cell lines and cervical tissues (12 normal and 42 cancerous) by using RT polymerase chain reaction (PCR). Methylation status of the PRDM5 promoter was studied using methylation-specific PCR (MSP). PRDM5 expression is reduced or lost in cervical cancers, compared with normal cervical tissues (P < 0.05). The current study results also showed that loss of PRDM5 is mediated by aberrant cytosine methylation of the PRDM5 promoter. There were 40.5% of carcinomas methylated, while none of normal tissues were methylated. PRDM5 mRNA expression was significantly higher (P = 0.000) in unmethylated (0.2634 ± 0.0674, mean ± SD), compared with methylated tissues (0.1007 ± 0.0993, mean ± SD). Last, treatment with a DNA methyltransferase inhibitor led to reactivation of PRDM5 expression in cell lines that had negligible PRDM5 expression at baseline. Reduced expression of PRDM5 may play an important role in the pathogenesis and/or development of cervical cancer, and is considered to be caused in part by aberrant DNA methylation.

Expression of the mouse PR domain protein Prdm8 in the developing central nervous system

It was first shown in the PR ( PRDI-BF1 and RIZ homology) domain family proteins that the PR domain has homology to the SET ( Su(var)3-9, Enhancer-of-zeste and Trithorax) domain, a catalytic domain of the histone lysine methyltransferases. Recently, there are many reports that the PR domain proteins have important roles in development and/or cell differentiation. In this report, we show the expression patterns of one of the mouse PR domain proteins, Prdm8, in the developing central nervous system. In the developing retina, Prdm8 expression was detected in postmitotic neurons in the inner nuclear layer and the ganglion cell layer, and its expression became restricted predominantly to the rod bipolar cells when retinogenesis was completed. In the developing spinal cord, Prdm8 was expressed first in the progenitor populations of ventral interneurons and motor neurons, and later in a subpopulation of interneurons. In the developing brain, Prdm8 expression was observed in postmitotic neurons in the intermediate zone and the cortical plate. In the postnatal brain, Prdm8 was expressed mainly in layer 4 neurons of the cerebral cortex. These results show that Prdm8 expression is tightly regulated in a spatio-temporal manner during neural development and mainly restricted to postmitotic neurons, except in the spinal cord.

Gene Amplification and Overexpression of PRDM14 in Breast Cancers

Several genes that encode PR (PRDI-BF1 and RIZ) domain proteins (PRDM) have been linked to human cancers. To explore the role of the PR domain family genes in breast carcinogenesis, we examined the expression profiles of 16 members of the PRDM gene family in a panel of breast cancer cell lines and primary breast cancer specimens using semiquantitative real-time PCR. We found that PRDM14 mRNA is overexpressed in about two thirds of breast cancers; moreover, immunohistochemical analysis showed that expression of PRDM14 protein is also up-regulated. Analysis of the gene copy number revealed that PRDM14 is a target of gene amplification on chromosome 8q13, which is a region where gene amplification has frequently been detected in various human tumors. Introduction of PRDM14 into cancer cells enhanced cell growth and reduced their sensitivity to chemotherapeutic drugs. Conversely, knockdown of PRDM14 by siRNA induced apoptosis in breast cancer cells and increased their sensitivity to chemotherapeutic drugs, suggesting that up-regulated expression of PRDM14 may play an important role in the proliferation of breast cancer cells. That little or no expression of PRDM14 is seen in noncancerous tissues suggests that PRDM14 could be an ideal therapeutic target for the treatment of breast cancer.

PRDM5 Identified as a Target of Epigenetic Silencing in Colorectal and Gastric Cancer

PR (PRDI-BF1 and RIZ) domain proteins (PRDM) are a subfamily of the kruppel-like zinc finger gene products that play key roles during cell differentiation and malignant transformation. The aim of the present study was to begin to examine the involvement of epigenetic alteration of PRDM expression in gastric and colorectal cancer. We used real-time PCR to assess expression of PRDM1-17. In addition, we used bisulfite PCR to assess DNA methylation and chromatin immunoprecipitation to assess histone modification in colorectal and gastric cancer cell lines lacking PRDM5 expression. Among the 17 PRDM family genes tested, we found that PRDM5 is the most frequently silenced in colorectal and gastric cancer cell lines. Silencing of PRDM5 was mediated by either DNA methylation or trimethylation of Lys(27) of histone H3. Introduction of PRDM5 into cancer cells suppressed cell growth, suggesting that it acts as a tumor suppressor in gastrointestinal cancers. Methylation of PRDM5 was detected in 6.6% (4 of 61) of primary colorectal and 50.0% (39 of 78) of primary gastric cancers but not in noncancerous tissue samples collected from areas adjacent to the tumors. Our data suggest that epigenetic alteration of PRDM5 (e.g., methylation of its 5'-CpG island or trimethylation of Lys(27) of histone H3) likely plays a key role in the progression of gastrointestinal cancers and may be a useful molecular marker.

PRISM/PRDM6, a Transcriptional Repressor That Promotes the Proliferative Gene Program in Smooth Muscle Cells

Smooth muscle cells (SMCs) display remarkable phenotypic diversity and plasticity and can readily switch between proliferative and differentiated states in response to extracellular cues. In an effort to identify novel transcriptional regulators of smooth muscle phenotypes, we compared the gene expression profiles of arterial and venous SMCs by microarray-based transcriptional profiling. Among numerous genes displaying distinct expression patterns in these two SMC types, we discovered an expressed sequence tag encoding a previously uncharacterized zinc finger protein belonging to the PRDM (PRDI-BF1 and RIZ homology domain) family of chromatin-remodeling proteins and named it PRISM (PR domain in smooth muscle). PRISM is expressed in a variety of smooth muscle-containing tissues and displays especially robust expression in the cardiac outflow tract and descending aorta during embryogenesis. PRISM is localized to the nucleus and contains an amino-terminal PR domain and four Krüppel-like zinc fingers at the carboxy terminus. We show that PRISM acts as a transcriptional repressor by interacting with class I histone deacetylases and the G9a histone methyltransferase, thereby identifying PRISM as a novel SMC-restricted epigenetic regulator. Overexpression of PRISM in cultured primary SMCs induces genes associated with the proliferative smooth muscle phenotype while repressing regulators of differentiation, including myocardin and GATA-6. Conversely, small interfering RNA-mediated knockdown of PRISM slows cell growth and induces myocardin, GATA-6, and markers of SMC differentiation. We conclude that PRISM acts as a novel epigenetic regulator of SMC phenotypic plasticity by suppressing differentiation and maintaining the proliferative potential of vascular SMCs.

PRDM5 is silenced in human cancers and has growth suppressive activities.

Several genes that contain the PR (PRDI-BF1 and RIZ) domain have been linked with human cancers. We describe here a new PR-domain-containing gene designated as PRDM5 (PFM2). A PRDM5 cDNA was isolated based on its homology to the PR domain of RIZ1 (PRDM2). The gene encodes an open reading frame of 630 amino acids and contains a PR domain in the NH-terminal region followed by 16 zinc finger motifs. Radiation hybrid analysis mapped PRDM5 to human chromosome 4q26, a region thought to harbor tumor suppressor genes for breast, ovarian, liver, lung, colon, and other cancers. The gene has a CpG island promoter and is silenced in human breast, ovarian, and liver cancers. A recombinant adenovirus expressing PRDM5 caused G2/M arrest and apoptosis upon infection of tumor cells. These results suggest that inactivation of PRDM5 may play a role in carcinogenesis.

Altered expression of retinoblastoma protein-interacting zinc finger gene, RIZ, in human leukaemia.

The retinoblastoma protein-interacting zinc finger gene (RIZ), a member of the nuclear protein methyltransferase superfamily, is characterized by the presence of the N-terminal PR domain. The RIZ gene encodes for two proteins, RIZ1 and RIZ2. While RIZ1 contains the PR (PRDI-BF1 and RIZ homologous) domain, RIZ2 lacks it. RIZ gene expression is altered in a variety of human cancers and RIZ1 is now considered to be a candidate tumour suppressor. To investigate the role of RIZ in leukaemogenesis, we analysed the differential expression of RIZ1 and RIZ2 by quantitative real-time reverse-transcription polymerase chain reaction assay. Our results showed that the expression of RIZ1 was significantly decreased in leukaemia cell lines (14 out of 17, 82%) and in patients with acute myeloblastic leukaemia (eight out of 14, 57%). In contrast, RIZ2 expression was increased in patients with acute lymphoblastic leukaemia (eight out of 11, 73%), compared with normal bone marrow cells. These findings indicate that suppression of RIZ1 expression or enhancement of RIZ2 expression may have an important role in leukaemogenesis.

Nucleotide Alteration of Retinoblastoma Protein-Interacting Zinc Finger Gene, RIZ, in Human Leukemia.

The retinoblastoma protein-interacting zinc finger gene (RIZ) is a zinc-finger type DNA binding protein and is postulated as a member of the nuclear protein-methyltransferase superfamily. RIZ gene encodes for two proteins, RIZ1 and RIZ2. While RIZ1 contains the N-terminal PR (PRDI-BF1 and RIZ homologous)-domain, RIZ2 lacks it. RIZ1 is now considered as a tumor suppressor. We analyzed nucleotide alteration of RIZ gene in human leukemia. The results revealed a single nucleotide polymorphism (SNP), T1704 to A, near the conserved Rb-binding domain, leading to an amino acid change, Asp283 to Glu. Interestingly, 17 of 21 leukemia cell lines are homozygous for the T1704 allele whereas only 2 of 20 normal subjects are homozygous for the allele. In addition, one base pair deletion in the poly (A)9 tract in the coding region near the C-terminal zinc-fingers was identified, resulting in frameshift, in 1 out of 17 leukemia cell lines, but no mutation in samples from 15 patients with acute lymphoblastic leukemia (ALL) and 6 patients with adult T cell leukemia (ATL). In the PR or SH3 (src homology 3) domain of the RIZ gene, no mutation was found. These findings suggest that RIZ may be a possible target of structural alteration leading to leukemia.