Gene Summary

Gene:PKD1; polycystin 1, transient receptor potential channel interacting
Aliases: PBP, PC1, Pc-1, TRPP1
Summary:This gene encodes a member of the polycystin protein family. The encoded glycoprotein contains a large N-terminal extracellular region, multiple transmembrane domains and a cytoplasmic C-tail. It is an integral membrane protein that functions as a regulator of calcium permeable cation channels and intracellular calcium homoeostasis. It is also involved in cell-cell/matrix interactions and may modulate G-protein-coupled signal-transduction pathways. It plays a role in renal tubular development, and mutations in this gene cause autosomal dominant polycystic kidney disease type 1 (ADPKD1). ADPKD1 is characterized by the growth of fluid-filled cysts that replace normal renal tissue and result in end-stage renal failure. Splice variants encoding different isoforms have been noted for this gene. Also, six pseudogenes, closely linked in a known duplicated region on chromosome 16p, have been described. [provided by RefSeq, Oct 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 11 March, 2017


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Recombinant Fusion Proteins
  • Cysts
  • Genetic Linkage
  • Signal Transduction
  • TRPP Cation Channels
  • Neoplasm Invasiveness
  • Pedigree
  • Genetic Markers
  • Cell Movement
  • Transcription Factors
  • Liver Diseases
  • Phosphorylation
  • Kidney
  • Mutation
  • Molecular Sequence Data
  • Protein Kinases
  • Repressor Proteins
  • Polycystic Kidney, Autosomal Dominant
  • Gene Deletion
  • Polycystic Kidney Diseases
  • Exons
  • Phenotype
  • Tumor Suppressor Gene
  • Prostate Cancer
  • Infant
  • Stomach Cancer
  • Childhood Cancer
  • Cell Proliferation
  • X-Ray Computed Tomography
  • DNA Mutational Analysis
  • Chromosome Mapping
  • Cancer Gene Expression Regulation
  • Protein Kinase C
  • Tuberous Sclerosis
  • Proteins
  • Loss of Heterozygosity
  • Polymerase Chain Reaction
  • Chromosome 16
  • Base Sequence
Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (2)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: PKD1 (cancer-related)

Tabuchi Y, Kitamura T, Fukuhara A, et al.
Nur77 gene expression levels were involved in different ACTH-secretion autonomy between Cushing's disease and subclinical Cushing's disease.
Endocr J. 2016; 63(6):545-54 [PubMed] Related Publications
Cushing's disease (CD) and subclinical Cushing's disease (subCD) are both diseases caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas. However, ACTH autonomy in subCD is weaker than in CD and there are no Cushingoid features in subCD. The differences of molecular mechanisms in ACTH autonomy between CD and subCD have not yet been reported. Therefore, we aimed to investigate the differences in molecular mechanisms of ACTH-secretion autonomy between CD and subCD. The study included 23 patients [7 CD, 6 subCD, and 10 non-functioning pituitary tumors (NFTs)] who underwent transsphenoidal surgery at the Osaka University Hospital between December 2009 and October 2013. Using quantitative real-time PCR, various ACTH-related gene expressions in tumor tissues from CD, subCD, and NFT were measured such as pro-opiomelanocortin (POMC), POMC transcription factor (Tpit, Pitx1, NeuroD1, and Nur77), POMC peptide processing enzymes (prohormone convertase: PC1/3 and PC2), and ACTH secretion-related factors (corticotropin-releasing hormone receptor 1: CRHR1 and glucocorticoid receptor α: GRα). Only Nur77 mRNA levels were significantly higher in CD than in subCD. Furthermore, we stained 6 CD and 6 subCD with anti-Nur77 antibody. All tumor samples from CD had Nur77 protein positive cells. On the other hand, Nur77 protein was expressed in only one tumor sample from subCD. This sample showed high expression of Nur77 mRNA. Nur77 is an important to regulate POMC transcription and negative-feedback by glucocorticoids. Nur77 gene expression levels might involve different autonomy of ACTH production between CD and subCD.

Sinha R, Ahn J, Sampson JN, et al.
Fecal Microbiota, Fecal Metabolome, and Colorectal Cancer Interrelations.
PLoS One. 2016; 11(3):e0152126 [PubMed] Free Access to Full Article Related Publications
BACKGROUND AND AIMS: Investigation of microbe-metabolite relationships in the gut is needed to understand and potentially reduce colorectal cancer (CRC) risk.
METHODS: Microbiota and metabolomics profiling were performed on lyophilized feces from 42 CRC cases and 89 matched controls. Multivariable logistic regression was used to identify statistically independent associations with CRC. First principal coordinate-component pair (PCo1-PC1) and false discovery rate (0.05)-corrected P-values were calculated for 116,000 Pearson correlations between 530 metabolites and 220 microbes in a sex*case/control meta-analysis.
RESULTS: Overall microbe-metabolite PCo1-PC1 was more strongly correlated in cases than in controls (Rho 0.606 vs 0.201, P = 0.01). CRC was independently associated with lower levels of Clostridia, Lachnospiraceae, p-aminobenzoate and conjugated linoleate, and with higher levels of Fusobacterium, Porphyromonas, p-hydroxy-benzaldehyde, and palmitoyl-sphingomyelin. Through postulated effects on cell shedding (palmitoyl-sphingomyelin), inflammation (conjugated linoleate), and innate immunity (p-aminobenzoate), metabolites mediated the CRC association with Fusobacterium and Porphyromonas by 29% and 34%, respectively. Overall, palmitoyl-sphingomyelin correlated directly with abundances of Enterobacteriaceae (Gammaproteobacteria), three Actinobacteria and five Firmicutes. Only Parabacteroides correlated inversely with palmitoyl-sphingomyelin. Other lipids correlated inversely with Alcaligenaceae (Betaproteobacteria). Six Bonferroni-significant correlations were found, including low indolepropionate and threnoylvaline with Actinobacteria and high erythronate and an uncharacterized metabolite with Enterobacteriaceae.
CONCLUSIONS: Feces from CRC cases had very strong microbe-metabolite correlations that were predominated by Enterobacteriaceae and Actinobacteria. Metabolites mediated a direct CRC association with Fusobacterium and Porphyromonas, but not an inverse association with Clostridia and Lachnospiraceae. This study identifies complex microbe-metabolite networks that may provide insights on neoplasia and targets for intervention.

Tan X, Liu P, Huang Y, et al.
Phosphoproteome Analysis of Invasion and Metastasis-Related Factors in Pancreatic Cancer Cells.
PLoS One. 2016; 11(3):e0152280 [PubMed] Free Access to Full Article Related Publications
Mechanisms of abnormal protein phosphorylation that regulate cell invasion and metastasis in pancreatic cancer remain obscure. In this study, we used high-throughput phosphorylation array to test two pancreatic cancer cell lines (PC-1 cells with a low, and PC-1.0 cells with a high potential for invasion and metastasis). We noted that a total of 57 proteins revealed a differential expression (fold change ≥ 2.0). Six candidate proteins were further validated by western blot with results found to be accordance with the array. Of 57 proteins, 32 up-regulated proteins (e.g. CaMK1-α and P90RSK) were mainly involved in ErbB and neurotrophin signaling pathways as determined using DAVID software, while 25 down-regulated proteins (e.g. BID and BRCA1) were closely involved in apoptosis and p53 signaling pathways. Moreover, four proteins (AKT1, Chk2, p53 and P70S6K) with different phosphorylation sites were found, not only among up-regulated, but also among down-regulated proteins. Importantly, specific phosphorylation sites can affect cell biological functions. CentiScaPe software calculated topological characteristics of each node in the protein-protein interaction (PPI) network: we found that AKT1 owns the maximum node degrees and betweenness in the up-regulation protein PPI network (26 nodes, average path length: 1.89, node degrees: 6.62±4.18, betweenness: 22.23±35.72), and p53 in the down-regulation protein PPI network (17 nodes, average path length: 2.04, node degrees: 3.65±2.47, betweenness: 16.59±29.58). In conclusion, the identification of abnormal protein phosphorylation related to invasion and metastasis may allow us to identify new biomarkers in an effort to develop novel therapeutic drug targets for pancreatic cancer treatment.

Genrich G, Kruppa M, Lenk L, et al.
The anti-oxidative transcription factor Nuclear factor E2 related factor-2 (Nrf2) counteracts TGF-β1 mediated growth inhibition of pancreatic ductal epithelial cells -Nrf2 as determinant of pro-tumorigenic functions of TGF-β1.
BMC Cancer. 2016; 16:155 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Nuclear factor E2 related factor-2 (Nrf2) is an oxidative stress inducible transcription factor being essential in regulating cell homeostasis. Thus, acute induction of Nrf2 in epithelial cells exposed to inflammation confers protection from oxidative cell damage and mutagenesis supporting an anti-tumorigenic role for Nrf2. However, pancreatic ductal adenocarcinoma (PDAC) is characterized by persistent Nrf2 activity conferring therapy resistance which points to a pro-tumorigenic role of Nrf2. A similar dichotomous role in tumorigenesis is described for the Transforming Growth Factor-beta 1 (TGF-β1). The present study therefore aimed at elucidating whether the switch of Nrf2 function towards a tumor promoting one relates to the modulation of TGF-β1 induced cell responses and whether this might occur early in PDAC development.
METHODS: In situ analysis comprised immunohistochemical stainings of activated (phosphorylated) Nrf2 and Ki67 in pancreatic tissues containing normal ducts and pancreatic intraepithelial neoplasia (PanINs). In vitro, Nrf2 levels in benign (H6c7-pBp), premalignant (H6c7-kras) and malignant (Colo357) pancreatic ductal epithelial cells were modulated by Nrf2 specific siRNA or Nrf2 overexpression. Then, the effect of Nrf2 alone and in combination with TGF-β1 on cell growth and survival was investigated by cell counting, Ki67 staining and apoptosis assays. The underlying cell signaling was investigated by western blotting. Statistical analysis was performed by Shapiro-Wilk test for normal distribution. Parametric data were analyzed by one-way ANOVA, while non-parametric data were analyzed by Kruskal-Wallis one-way ANOVA on ranks.
RESULTS: Significantly elevated expression of activated Nrf2 and Ki67 could be detected in PanINs but not in normal pancreatic ductal epithelium. While the effect of Nrf2 on basal cell growth of H6c7-pBp, H6c7-kras and Colo357 cells was minor, it clearly attenuated the growth inhibiting effects of TGF-β1 in all cell lines. This enhanced Nrf2-mediated cell survival was predominantly based on an enhanced proliferative activity. Accordingly, expression of p21 expression along with expression of phospho-p38 and phospho-Smad3 was diminished whereas Erk-phosphorylation was enhanced under these conditions.
CONCLUSIONS: Overall, our data demonstrate that Nrf2 being elevated in early precursor lesions counteracts the growth inhibiting function of TGF-β1 already in benign and premalignant pancreatic ductal epithelial cells. This could represent one fundamental mechanism underlying the functional switch of both- TGF-β1 and Nrf2 - which may manifest already in early stages of PDAC development.

Nishijima N, Seike M, Soeno C, et al.
miR-200/ZEB axis regulates sensitivity to nintedanib in non-small cell lung cancer cells.
Int J Oncol. 2016; 48(3):937-44 [PubMed] Free Access to Full Article Related Publications
Nintedanib (BIBF1120) is a multi-targeted angiokinase inhibitor and has been evaluated in idiopathic pulmonary fibrosis and advanced non-small cell lung cancer (NSCLC) patients in clinical studies. In the present study, we evaluated the antitumor effects of nintedanib in 16 NSCLC cell lines and tried to identify microRNA (miRNA) associated with sensitivity to nintedanib. No correlations between FGFR, PDGFR and VEGFR family activation and sensitivity to nintedanib were found. The difference in miRNA expression profiles between 5 nintedanib-sensitive and 5 nintedanib-resistant cell lines was evaluated by miRNA array and quantitative RT-PCR analysis (qRT-PCR). Expression of miR-200b, miR-200a and miR-141 belonging to the miR-200 family which contributes to epithelial-mesenchymal transition (EMT), was significantly lower in 5 nintedanib-resistant than in 5 nintedanib-sensitive cell lines. We examined the protein expression of EMT markers in these 10 NSCLC cell lines. E-cadherin expression was lower, and vimentin and ZEB1 expression were higher in 5 nintedanib-resistant cell lines. PC-1 was the most sensitive of the NSCLC cell lines to nintedanib. We established nintedanib-resistant PC-1 cells (PC-1R) by the stepwise method. PC-1R cells also showed decreased expression of miR-200b, miR-141 and miR-429 and increased expression of ZEB1 and ZEB2. We confirmed that induction of miR-200b or miR-141 enhanced sensitivity to nintedanib in nintedanib-resistant A549 and PC1-R cells. In addition, we evaluated the response to gefitinib in combination with nintedanib after TGF-β1 exposure of A549 cells. Nintedanib was able to reverse TGF-β1-induced EMT and resistance to gefitinib caused by miR-200b and miR-141 upregulation and ZEB1 downregulation. These results suggested that the miR-200/ZEB axis might be predictive biomarkers for sensitivity to nintedanib in NSCLC cells. Furthermore, nintedanib combined with gefitinib might be a novel therapeutic strategy for NSCLC cells with EMT phenotype and resistance to gefitinib.

Zhang W, Tan AY, Blumenfeld J, et al.
Papillary renal cell carcinoma with a somatic mutation in MET in a patient with autosomal dominant polycystic kidney disease.
Cancer Genet. 2016 Jan-Feb; 209(1-2):11-20 [PubMed] Related Publications
Autosomal-dominant polycystic kidney disease (ADPKD) is caused by mutations in PKD1 and PKD2 and is characterized by proliferation of renal tubular epithelium and progressive chronic kidney disease. Derangements in similar cellular signaling pathways occur in ADPKD and renal malignancies, although an association of these disorders has not been established. Herein, we present a case of papillary RCC (pRCC) incidentally discovered in a patient with ADPKD following bilateral native nephrectomy during renal transplantation. Whole exome sequencing of the pRCC found a somatic missense mutation in MET proto-oncogene, p.Val1110Ile, not present in kidney cyst epithelium or non-cystic tissue. RNA sequencing demonstrated increased mRNA expression of MET and pathway-related genes, but no significant copy number variation of MET was detected. Genetic analysis of PKD genes from peripheral blood lymphocytes and renal cyst epithelium identified a constitutional PKD1 germline mutation, p.Trp1582Ser, predicted to be pathogenic. Unique somatic mutations in PKD1 were also detected in 80% of the renal cysts analyzed, but not in the pRCC. These results suggest that, in this patient, the pRCC utilized a signaling pathway involving MET that was distinct from the pathogenesis of ADPKD. This is the first report of PKD1 mutations and a somatic mutation of the MET oncogene in a pRCC in ADPKD.

Park YR, Chun JN, So I, et al.
Data-driven Analysis of TRP Channels in Cancer: Linking Variation in Gene Expression to Clinical Significance.
Cancer Genomics Proteomics. 2016 Jan-Feb; 13(1):83-90 [PubMed] Related Publications
BACKGROUND: Experimental evidence has suggested that transient receptor potential (TRP) channels play a crucial role in tumor biology. However, clinical relevance and significance of TRP channels in cancer remain largely unknown.
MATERIALS AND METHODS: We applied a data-driven approach to dissect the expression landscape of 27 TRP channel genes in 14 types of human cancer using International Cancer Genome Consortium data.
RESULTS: TRPM2 was found overexpressed in most tumors, whereas TRPM3 was broadly down-regulated. TRPV4 and TRPA1 were found up- and down-regulated respectively in a cancer type-specific manner. TRPC4 was found to be closely associated with incidence of head and neck cancer and poor survival of patients with kidney cancer. TRPM8 was identified as a new molecular marker for lung cancer diagnosis and TRPP1 for kidney cancer prognosis.
CONCLUSION: Our data-driven approach demonstrates that the variation in the expression of TRP channel genes is manifested across various human cancer types and genes, for certain TRP channels have strong predictive diagnostic and prognostic potential.

Schell MJ, Yang M, Missiaglia E, et al.
A Composite Gene Expression Signature Optimizes Prediction of Colorectal Cancer Metastasis and Outcome.
Clin Cancer Res. 2016; 22(3):734-45 [PubMed] Free Access to Full Article Related Publications
PURPOSE: We previously found that an epithelial-to-mesenchymal transition (EMT)-based gene expression signature was highly correlated with the first principal component (PC1) of 326 colorectal cancer tumors and was prognostic. This study was designed to improve these signatures for better prediction of metastasis and outcome.
EXPERIMENTAL DESIGN: A total of 468 colorectal cancer tumors including all stages (I-IV) and metastatic lesions were used to develop a new prognostic score (ΔPC1.EMT) by subtracting the EMT signature score from its correlated PC1 signature score. The score was validated on six other independent datasets with a total of 3,697 tumors.
RESULTS: ΔPC1.EMT was found to be far more predictive of metastasis and outcome than its parent scores. It performed well in stages I to III, among microsatellite instability subtypes, and across multiple mutation-based subclasses, demonstrating a refined capacity to predict distant metastatic potential even in tumors with a "good" prognosis. For example, in the PETACC-3 clinical trial dataset, it predicted worse overall survival in an adjusted multivariable model for stage III patients (HR standardized by interquartile range [IQR] = 1.50; 95% confidence interval, 1.25-1.81; P = 0.000016, N = 644). The improved performance of ΔPC1.EMT was related to its propensity to identify epithelial-like subpopulations as well as mesenchymal-like subpopulations. Biologically, the signature was correlated positively with RAS signaling but negatively with mitochondrial metabolism. ΔPC1.EMT was a "best of assessed" prognostic score when compared with 10 other known prognostic signatures.
CONCLUSIONS: The study developed a prognostic signature score with a propensity to detect non-EMT features, including epithelial cancer stem cell-related properties, thereby improving its potential to predict metastasis and poorer outcome in stage I-III patients.

Zhu L, Liu J, Ma S, Zhang S
Long Noncoding RNA MALAT-1 Can Predict Metastasis and a Poor Prognosis: a Meta-Analysis.
Pathol Oncol Res. 2015; 21(4):1259-64 [PubMed] Related Publications
Elevated expression of MALAT-1 was found in various cancers, and correlated with metastasis and prognostic. This meta-analysis collected all relevant articles and explored correlation of MALAT-1 with lymph node metastasis (LNM), distant metastasis (DM), and overall survival (OS). A quantitative meta-analysis was performed through a systematic search in PubMed, Web of Science, Medline, CNKI, CBM, and the Cochrane Library. The odds ratios (OR) of LNM and DM and hazard ratio (HR) of OS were calculated to assess the association strength. Eight studies with a total of 845 patients were included in the meta-analysis. Six different types of cancer were evaluated, with 2 non-small cell lung cancer (NSCLC), 1 colorectal cancer (CRC), 1 gastric cancer (GC), 2 pancreatic cancer (PC), 1 clear cell renal cell carcinoma (ccRCC), and 1 osteosarcoma (OSA). Compared with low MALAT-1 expression, high MALAT-1 expression correlated with more LNM (OR = 2.08, 95 %CI: 1.00-4.32, p = 0.05) by a random-effects model (I (2) = 71 %, p = 0.004). A similar result was seen between MALAT-1 expression and DM, the OR was 3.52 (95 %CI: 1.06-11.71, p = 0.04) adopting a random-effects model (I (2) = 59 %, p = 0.04). Additionally, our analysis showed a poorer OS in patients with high MALAT-1 expression than those with low MALAT-1 expression (HR = 2.12, 95 %CI: 1.60-2.82, p < 0.001) adopting a random-effects model (I (2) = 56 %, p = 0.04). MALAT-1 may serve as a molecular marker for cancer metastasis and prognosis.

Kang HB, Lee HR, Jee da J, et al.
PRDM1, a Tumor-Suppressor Gene, is Induced by Genkwadaphnin in Human Colon Cancer SW620 Cells.
J Cell Biochem. 2016; 117(1):172-9 [PubMed] Related Publications
Genkwadaphnin (GD-1) is isolated from the flower buds of Daphne genkwa Siebold et Zuccarini (Thymelaeaceae), and it has been used as a traditional Korean and Chinese medicine. In this study, the authors observe that GD-1 inhibits the growth of the colon cancer cell line, SW620, through the up-regulation of p21 expression in a PRDM1-dependent manner. After treatment with GD-1, the transcriptional repressor PRDM1 is prominently induced in SW620 cells. Furthermore, GD-1 induce the phosphorylation of PKD1 and MEK and subsequently provide PRDM1 enhancement, resulting in the suppression of c-Myc expression and the up-regulation of p21. PKD1 knockdown using siRNA abrogates PRDM1 expression by GD-1 and subsequently disrupts the regulation of c-Myc and p21 expression. Treating SW620 cells with GD-1 inhibits cell-cycle progression and is characterized by the down-regulation of c-Myc followed by the up-regulation of p21 expression. The up-regulation of p21 by GD-1 induces the growth arrest of the SW620 colon cancer cell line. Based on these data, the authors propose that GD-1 has tumor-suppressor activity that may contribute to the anti-tumor effects of PRDM1 in colon cancer.

Cabrera-López C, Bullich G, Martí T, et al.
Insight into response to mTOR inhibition when PKD1 and TSC2 are mutated.
BMC Med Genet. 2015; 16:39 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Mutations in TSC1 or TSC2 cause the tuberous sclerosis complex (TSC), while mutations in PKD1 or PKD2 cause autosomal dominant polycystic kidney disease (ADPKD). PKD1 lays immediately adjacent to TSC2 and deletions involving both genes, the PKD1/TSC2 contiguous gene syndrome (CGS), are characterized by severe ADPKD, plus TSC. mTOR inhibitors have proven effective in reducing angiomyolipoma (AML) in TSC and total kidney volume in ADPKD but without a positive effect on renal function.
METHODS AND RESULTS: We describe a patient with independent truncating PKD1 and TSC2 mutations who has the expected phenotype for both diseases independently instead of the severe one described in PKD1/TSC2-CGS. Treatment with mTOR inhibitors reduced the AML and kidney volume for 2 years but thereafter they resumed growth; no positive effect on renal function was seen throughout. This is the first case addressing the response to mTOR treatment when independent truncating mutations in PKD1 and TSC2 are present.
CONCLUSIONS: This case reveals that although PKD1 and TSC2 are adjacent genes and there is likely cross-talk between the PKD1 and TSC2 signalling pathways regulating mTOR, having independent TSC2 and PKD1 mutations can give rise to a milder kidney phenotype than is typical in PKD1/TSC2-CGS cases. A short-term beneficial effect of mTOR inhibition on AML and total kidney volume was not reflected in improved renal function.

Yu L, Shang ZF, Wang J, et al.
PC-1/PrLZ confers resistance to rapamycin in prostate cancer cells through increased 4E-BP1 stability.
Oncotarget. 2015; 6(24):20356-69 [PubMed] Free Access to Full Article Related Publications
An important strategy for improving advanced PCa treatment is targeted therapies combined with chemotherapy. PC-1, a prostate Leucine Zipper gene (PrLZ), is specifically expressed in prostate tissue as an androgen-induced gene and is up-regulated in advanced PCa. Recent work confirmed that PC-1 expression promotes PCa growth and androgen-independent progression. However, how this occurs and whether this can be used as a biomarker is uncertain. Here, we report that PC-1 overexpression confers PCa cells resistance to rapamycin treatment by antagonizing rapamycin-induced cytostasis and autophagy (rapamycin-sensitivity was observed in PC-1-deficient (shPC-1) C4-2 cells). Analysis of the mTOR pathway in PCa cells with PC-1 overexpressed and depressed revealed that eukaryotic initiation factor 4E-binding protein 1(4E-BP1) was highly regulated by PC-1. Immunohistochemistry assays indicated that 4E-BP1 up-regulation correlates with increased PC-1 expression in human prostate tumors and in PCa cells. Furthermore, PC-1 interacts directly with 4E-BP1 and stabilizes 4E-BP1 protein via inhibition of its ubiquitination and proteasomal degradation. Thus, PC-1 is a novel regulator of 4E-BP1 and our work suggests a potential mechanism through which PC-1 enhances PCa cell survival and malignant progression and increases chemoresistance. Thus, the PC-1-4E-BP1 interaction may represent a therapeutic target for treating advanced PCa.

Zhou X, Fan LX, Peters DJ, et al.
Therapeutic targeting of BET bromodomain protein, Brd4, delays cyst growth in ADPKD.
Hum Mol Genet. 2015; 24(14):3982-93 [PubMed] Free Access to Full Article Related Publications
In this study, we identified a BET bromodomain (BRD) protein, Brd4, not only as a novel epigenetic regulator of autosomal dominant polycystic kidney disease (ADPKD) but also as a novel client protein of Hsp90. We found that Brd4 was upregulated in Pkd1 mutant mouse renal epithelial cells and tissues. This upregulation of Brd4 appears to result from the chaperone activity of Hsp90 and escape proteasomal degradation. We further identify that Brd4 is an upstream regulator of the expression of c-Myc which has been upregulated in all rodent models of PKD and ADPKD patients with unknown mechanism. Inhibition of Brd4 in Pkd1 mutant renal epithelial cells with JQ1, a selective small-molecular inhibitor of BET BRD protein(s), (1) decreased the levels of c-Myc mRNA and protein; (2) increased the levels of p21 mRNA and protein, which was transcriptionally repressed by c-Myc; (3) decreased the phosphorylation of Rb; and (4) decreased cystic epithelial cell proliferation as shown by inhibition of S-phase entry. Most importantly, treatment with JQ1 strikingly delayed cyst growth and kidney enlargement, and preserved renal function in two early stage genetic mouse strains with Pkd1 mutations. This study not only provides one of the mechanisms of how c-Myc is upregulated in PKD but also suggests that targeting Brd4 with JQ1 may function as a novel epigenetic approach in ADPKD. The unraveled link between Brd4 and Hsp90 in ADPKD may also be a general mechanism for the upregulation of Brd4 in cancer cells and opens up avenues for combination therapies against ADPKD and cancer.

Jin S, Cui K, Sun ZQ, et al.
Screening analysis of candidate gene mutations in a kindred with polycystic liver disease.
World J Gastroenterol. 2015; 21(8):2343-51 [PubMed] Free Access to Full Article Related Publications
AIM: To find potential mutable sites by detecting mutations of the candidate gene in a kindred with polycystic liver disease (PCLD).
METHODS: First, we chose a kindred with PCLD and obtained five venous blood samples of this kindred after the family members signed the informed consent form. In the kindred two cases were diagnosed with PCLD, and the left three cases were normal individuals. All the blood samples were preserved at -85 °C. Second, we extracted the genomic DNA from the venous blood samples of the kindred using a QIAamp DNA Mini Kit and then performed long-range polymerase chain reaction (PCR) with different primers. The exons of PKD1 were all sequenced with the forward and reverse primers to ensure the accuracy of the results. Next, we purified the PCR products and directly sequenced them using Big Dye Terminator Chemistry version 3.1. The sequencing reaction was conducted with BiomekFX (Beckman). Finally, we analyzed the results.
RESULTS: A total of 42 normal exons were identified in detecting mutations of the PKD1 gene. A synonymous mutation occurred in exon 5. The mutation was a homozygous T in the proband and was C in the reference sequence. This mutation was located in the third codon and did not change the amino acid encoded by the codon. Missense mutations occurred in exons 11 and 35. These mutations were located in the second codon; they changed the amino acid sequence and existed in the dbSNP library. A nonsense mutation occurred in exon 15. The mutation was a heterozygous CT in the proband and was C in the reference sequence. This mutation was located in the first codon and resulted in a termination codon. This mutation had an obvious influence on the encoded protein and changed the length of the protein from 4303 to 2246 amino acids. This was a new mutation that was not present in the dbSNP library.
CONCLUSION: The nonsense mutation of exon 15 existed in the proband and in the third individual. Additionally, the proband was heterozygous for this mutation, so the mutable site was a pathogenic mutation.

Caines R, Eleuteri A, Kalirai H, et al.
Cluster analysis of multiplex ligation-dependent probe amplification data in choroidal melanoma.
Mol Vis. 2015; 21:1-11 [PubMed] Free Access to Full Article Related Publications
PURPOSE: To determine underlying correlations in multiplex ligation-dependent probe amplification (MLPA) data and their significance regarding survival following treatment of choroidal melanoma (CM).
METHODS: MLPA data were available for 31 loci across four chromosomes (1p, 3, 6, and 8) in tumor material obtained from 602 patients with CM treated at the Liverpool Ocular Oncology Center (LOOC) between 1993 and 2012. Data representing chromosomes 3 and 8q were analyzed in depth since their association with CM patient survival is well-known. Unsupervised k-means cluster analysis was performed to detect latent structure in the data set. Principal component analysis (PCA) was also performed to determine the intrinsic dimensionality of the data. Survival analyses of the identified clusters were performed using Kaplan-Meier (KM) and log-rank statistical tests. Correlation with largest basal tumor diameter (LTD) was investigated.
RESULTS: Chromosome 3: A two-cluster (bimodal) solution was found in chromosome 3, characterized by centroids at unilaterally normal probe values and unilateral deletion. There was a large, significant difference in the survival characteristics of the two clusters (log-rank, p<0.001; 5-year survival: 80% versus 40%). Both clusters had a broad distribution in LTD, although larger tumors were characteristically in the poorer outcome group (Mann-Whitney, p<0.001). Threshold values of 0.85 for deletion and 1.15 for gain optimized the classification of the clusters. PCA showed that the first principal component (PC1) contained more than 80% of the data set variance and all of the bimodality, with uniform coefficients (0.28±0.03). Chromosome 8q: No clusters were found in chromosome 8q. Using a conventional threshold-based definition of 8q gain, and in conjunction with the chromosome 3 clusters, three prognostic groups were identified: chromosomes 3 and 8q both normal, either chromosome 3 or 8q abnormal, and both chromosomes 3 and 8q abnormal. KM analysis showed 5-year survival figures of approximately 97%, 80%, and 30% for these prognostic groups, respectively (log-rank, p<0.001). All MLPA probes within both chromosomes were significantly correlated with each other (Spearman, p<0.001).
CONCLUSIONS: Within chromosome 3, the strong correlation between the MLPA variables and the uniform coefficients from the PCA indicates a lack of evidence for a signature gene that might account for the bimodality we observed. We hypothesize that the two clusters we found correspond to binary underlying states of complete monosomy or disomy 3 and that these states are sampled by the complete ensemble of probes. Consequently, we would expect a similar pattern to emerge in higher-resolution MLPA data sets. LTD may be a significant confounding factor. Considering chromosome 8q, we found that chromosome 3 cluster membership and 8q gain as traditionally defined have an indistinguishable impact on patient outcome.

Galliani CA, Gomez AM, Panniello G, Bisceglia M
Selected case from the Arkadi M. Rywlin International Pathology Slide Series: Asymmetric, segmental glomerulocystic kidney in an infant with tuberous sclerosis complex.
Adv Anat Pathol. 2015; 22(2):135-43 [PubMed] Related Publications
A Hispanic newborn male, the product of nonconsanguineous parents, exhibited major and minor signs of tuberous sclerosis complex (TSC). MRI of the abdomen disclosed a discrete unilateral, cystic, right upper pole renal mass that prompted a nephrectomy. Histologic examination showed a polycystic renal mass that involved all segments of the nephron, with a preponderantly glomerulocystic pattern. The cysts were rounded, uniform, and small, most measuring 2 to 3 mm in diameter. The lining of the cysts was hyperplastic, made up of tall epithelial cells with eosinophilic granular cytoplasm and large nuclei, and focally formed mounds and papillary tufts. DNA analysis detected a constitutional deletion of exon 1 in the TSC2 gene on chromosome 16p13.3. Cystogenesis in TSC2 is manifested because of alteration or dysfunction of the primary cilium, where polycystin, the gene product of PKD1 gene, is localized. Renal cysts are often seen in TSC, varying in number from a few to innumerable, involving all segments of the nephron, including Bowman spaces, and are currently considered as one of the minor diagnostic features. A glomerulocystic pattern is a rare form of kidney involvement in TSC that aptly describes the innumerable cystically dilated Bowman spaces. Glomerulocystic kidney associated with the aforementioned hyperplastic epithelial lining (TSC epithelium) is sufficiently characteristic that could conceivably serve as a major TSC feature in the future.

Kang HB, Ahn KS, Oh SR, Kim JW
Genkwadaphnin induces IFN-γ via PKD1/NF-κB/STAT1 dependent pathway in NK-92 cells.
PLoS One. 2014; 9(12):e115146 [PubMed] Free Access to Full Article Related Publications
The flower buds of Daphne genkwa Sieb. et Zucc. have been used as a traditional Chinese medicine although their functional mechanisms have not been discovered yet. We have studied the potential effects of the plant extracts on natural killer (NK) cell activation, and isolated an active fraction. Genkwadaphnin (GD-1) displayed a potent efficacy to induce IFN-γ transcription in NK cells with concentration- and time-dependent manners. GD-1 treatment triggered the phosphorylation of PKD1, a member of PKC family, MEK and ERK, resulting in IKK activation to induce IκB degradation, and the nuclear localization of p65, an NF-κB subunit, which regulates IFN-γ transcription. GD-1 effect on IFN-γ production was blocked by the addition of Rottlerin, a PKC inhibitor, CID 755673, a PKD inhibitor, or Bay11-7082, an IKKα inhibitor. The nuclear localization of p65 was also inhibited by the kinase inhibitors. Secreted IFN-γ activates STAT1 phosphorylation as autocrine-loops to sustain its secretion. GD-1 induced the phosphorylation of STAT1 probably through the increase of IFN-γ. STAT1 inhibitor also abrogated the sustained IFN-γ secretion. These results suggest that GD-1 is involved in the activation of PKD1 and/or ERK pathway, which activate NK-κB triggering IFN-γ production. As positive feedback loops, secreted IFN-γ activates STAT1 and elongates its production in NK-92 cells.

Karam M, Bièche I, Legay C, et al.
Protein kinase D1 regulates ERα-positive breast cancer cell growth response to 17β-estradiol and contributes to poor prognosis in patients.
J Cell Mol Med. 2014; 18(12):2536-52 [PubMed] Free Access to Full Article Related Publications
About 70% of human breast cancers express and are dependent for growth on estrogen receptor α (ERα), and therefore are sensitive to antiestrogen therapies. However, progression to an advanced, more aggressive phenotype is associated with acquisition of resistance to antiestrogens and/or invasive potential. In this study, we highlight the role of the serine/threonine-protein kinase D1 (PKD1) in ERα-positive breast cancers. Growth of ERα-positive MCF-7 and MDA-MB-415 human breast cancer cells was assayed in adherent or anchorage-independent conditions in cells overexpressing or depleted for PKD1. PKD1 induces cell growth through both an ERα-dependent manner, by increasing ERα expression and cell sensitivity to 17β-estradiol, and an ERα-independent manner, by reducing cell dependence to estrogens and conferring partial resistance to antiestrogen ICI 182,780. PKD1 knockdown in MDA-MB-415 cells strongly reduced estrogen-dependent and independent invasion. Quantification of PKD1 mRNA levels in 38 cancerous and non-cancerous breast cell lines and in 152 ERα-positive breast tumours from patients treated with adjuvant tamoxifen showed an association between PKD1 and ERα expression in 76.3% (29/38) of the breast cell lines tested and a strong correlation between PKD1 expression and invasiveness (P < 0.0001). In tamoxifen-treated patients, tumours with high PKD1 mRNA levels (n = 77, 50.66%) were significantly associated with less metastasis-free survival than tumours with low PKD1 mRNA expression (n = 75, 49.34%; P = 0.031). Moreover, PKD1 mRNA levels are strongly positively associated with EGFR and vimentin levels (P < 0.0000001). Thus, our study defines PKD1 as a novel attractive prognostic factor and a potential therapeutic target in breast cancer.

Wu R, Wang H, Wang J, et al.
EphA3, induced by PC-1/PrLZ, contributes to the malignant progression of prostate cancer.
Oncol Rep. 2014; 32(6):2657-65 [PubMed] Related Publications
Our previous study revealed the potential linkage of PC-1/PrLZ, a novel isolated prostate-specific gene, to the progression of prostate cancer (PCa) in vitro and in vivo. To gain more insight into the mechanism of PC-1-induced promotion of PCa, expression analysis of differential genes induced by PC-1 was scanned by microarray. Among all the differentially expressed genes, EphA3 was altered to the greatest extent. EphA3 has been identified to be associated with multiple tumor progression. However, little is known concerning the function of EphA3 in PCa. In the present study, we aimed to ascertain whether EphA3 is induced by PC-1 and the functional significance of EphA3 expression in PCa. We found that overexpression of PC-1 increased the amount of EphA3 and that knockdown of PC-1 led to a decrease in EphA3 in PCa cells. The functional significance and mechanisms by which EphA3 contributes to PCa was investigated in vitro using cell lines, and in vivo using a mouse model and clinical specimens. The results showed that EphA3 enhanced the proliferation and survival of LNCaP cells and suppression of EphA3 inhibited the survival of C4-2B cells. EphA3 enhanced the tumor development of LNCaP cells in null mice. A positive correlation between the levels of EphA3 and the Gleason grade of PCa was identified in clinical PCa specimens. In addition, cellular localization changed with Gleason grade. We further detected that EphA3 increased phosphorylation of Akt (Ser473 and Thr308), indicating that EphA3 activated the Akt pathway. Taken together, EphA3 was induced by PC-1 and contributed to the malignant progression of prostate cancer. Our results provide the first demonstration that EphA3 is a novel promoter of human prostate cancer development and progression.

Stope MB, Weiss M, Preuss M, et al.
Immediate and transient phosphorylation of the heat shock protein 27 initiates chemoresistance in prostate cancer cells.
Oncol Rep. 2014; 32(6):2380-6 [PubMed] Related Publications
Drug resistance minimizes the effects of prostate cancer (PC) chemotherapy with docetaxel and is generally considered to be associated with the expression of heat shock protein (HSP) 27 including various cytoprotective pathways. In the present study, we investigated the effects of HSP27 phosphorylation on PC cell growth underlying docetaxel treatment. Cell counting revealed significantly reduced cell growth during docetaxel treatment as a result of both activation of mitogen-activated protein kinase p38 (MAPK p38) and protein kinase D1 (PKD1), and, most importantly, the overexpression of the phosphorylation-mimicking mutant HSP27-3D. Further analysis revealed a docetaxel-dependent induction of HSP27 accompanied by an initial phosphorylation and rapid dephosphorylation of the protein. Based on the data, we can conclude that phosphorylation of HSP27 protein is a crucial mechanism in the initiation of chemoresistance in PC. Moreover, the results indicate a key impact of HSP27 on viability and proliferation of PC cells underlying anticancer therapy. The protective function depends on the initial phosphorylation status of HSP27 and represents a putative co-therapeutic target to prevent chemoresistance during docetaxel therapy.

Kotulska K, Borkowska J, Mandera M, et al.
Congenital subependymal giant cell astrocytomas in patients with tuberous sclerosis complex.
Childs Nerv Syst. 2014; 30(12):2037-42 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Subependymal giant cell astrocytoma (SEGA) is a brain tumor associated with tuberous sclerosis complex (TSC). It usually grows in a second decade of life, but may develop in the first months of life. The aim of this work was to establish the incidence, clinical features, and outcome of congenital SEGA in TSC patients.
METHODS: Cohort of 452 TSC patients was reviewed to identify cases with growing or hydrocephalus producing SEGAs in the first 3 months of life. Clinical presentation, size of the tumor, growth rate, mutational analysis, treatment applied, and outcome were analyzed.
RESULTS: Ten (2.2 %) patients presented with SEGA in the first 3 months of life. All of them had documented SEGA growth and all developed hydrocephalus. In eight patients, mutational analysis was done, and in all of them, TSC2 gene mutations were identified. Mean maximum SEGA diameter at baseline was 21.8 mm. Mean SEGA growth rate observed postnatally was 2.78 mm per month and tended to be higher (5.43 mm per month) in patients with TSC2/PKD1 mutation than in other cases. Seven patients underwent SEGA surgery and surgery-related complications were observed in 57.1 % cases. One patient was successfully treated with everolimus as a primary treatment.
CONCLUSIONS: Congenital SEGA develops 2.2 % of TSC patients. Patients with TSC2 mutations, and especially with TSC2/PKD1 mutations, are more prone to develop SEGA earlier in childhood and should be screened for SEGA from birth. In young infants with SEGA, both surgery and mTOR inhibitor should be considered as a treatment option.

Donnard E, Asprino PF, Correa BR, et al.
Mutational analysis of genes coding for cell surface proteins in colorectal cancer cell lines reveal novel altered pathways, druggable mutations and mutated epitopes for targeted therapy.
Oncotarget. 2014; 5(19):9199-213 [PubMed] Free Access to Full Article Related Publications
We carried out a mutational analysis of 3,594 genes coding for cell surface proteins (Surfaceome) in 23 colorectal cancer cell lines, searching for new altered pathways, druggable mutations and mutated epitopes for targeted therapy in colorectal cancer. A total of 3,944 somatic non-synonymous substitutions and 595 InDels, occurring in 2,061 (57%) Surfaceome genes were catalogued. We identified 48 genes not previously described as mutated in colorectal tumors in the TCGA database, including genes that are mutated and expressed in >10% of the cell lines (SEMA4C, FGFRL1, PKD1, FAM38A, WDR81, TMEM136, SLC36A1, SLC26A6, IGFLR1). Analysis of these genes uncovered important roles for FGF and SEMA4 signaling in colorectal cancer with possible therapeutic implications. We also found that cell lines express on average 11 druggable mutations, including frequent mutations (>20%) in the receptor tyrosine kinases AXL and EPHA2, which have not been previously considered as potential targets for colorectal cancer. Finally, we identified 82 cell surface mutated epitopes, however expression of only 30% of these epitopes was detected in our cell lines. Notwithstanding, 92% of these epitopes were expressed in cell lines with the mutator phenotype, opening new venues for the use of "general" immune checkpoint drugs in this subset of patients.

Zhang R, Leng H, Huang J, et al.
miR-337 regulates the proliferation and invasion in pancreatic ductal adenocarcinoma by targeting HOXB7.
Diagn Pathol. 2014; 9:171 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: miRNAs are involved in coordinating a variety of cellular processes by regulating their target genes. Aberrant expression of miRNAs is correlated with various cancers. Previous studies have shown that miR-337 is significantly down-regulated in pancreatic ductal adenocarcinoma (PDAC) and that its expression is negatively correlated to the expression of HOXB7. Both miR-337 and HOXB7 are associated with the prognosis of PDAC patients. The purpose of this study was to identify the molecular mechanisms by which miR-337 acts as a tumor suppressor in PDAC.
METHODS: Synthetic miR-337 mimics were transfected into PANC-1 and As-PC-1 cells using Lipofectamine™ 2000. The expression of HOXB7 protein was analyzed by Western blot. Luciferase reporter plasmids were constructed to confirm that HOXB7 3'UTR was the target of miR-337. The effect of miR-337 on cell proliferation was evaluated by CCK8 assay and colony formation assay, and cell invasion was evaluated by wound healing assay and transwell assay.
RESULTS: Western blot and luciferase activity assays identified HOXB7 as the target of miR-337. A CCK-8 assay showed the absorbance of cells transfected with miR-337 mimics to be less than that of control cells, and that the number of cell clones was significantly decreased by miR-337 expression. A wound healing assay showed the invasion rate of cells transfected with miR-337 mimics at 36 h to be markedly lower than in controls. The average number of cells penetrating the Matrigel was significantly lower than the controls.
CONCLUSION: These findings suggest that miR-337 targets HOXB7 and effects significant suppression of PDAC cell proliferation and invasion.
VIRTUAL SLIDES: The virtual slide(s) for this article can be found here:

Hui K, Yang Y, Shi K, et al.
The p38 MAPK-regulated PKD1/CREB/Bcl-2 pathway contributes to selenite-induced colorectal cancer cell apoptosis in vitro and in vivo.
Cancer Lett. 2014; 354(1):189-99 [PubMed] Related Publications
Supranutritional selenite has anti-cancer therapeutic effects in vivo; however, the detailed mechanisms underlying these effects are not clearly understood. Further studies would broaden our understanding of the anti-cancer effects of this compound and provide a theoretical basis for its clinical application. In this study, we primarily found that selenite exposure inhibited phosphorylation of cyclic adenosine monophosphate (cAMP)-response element binding protein (CREB), leading to suppression of Bcl-2 in HCT116 and SW480 colorectal cancer (CRC) cells. Moreover, the selenite-induced inhibitory effect on PKD1 activation was involved in suppression of the CREB signalling pathway. Additionally, we discovered that selenite treatment can upregulate p38 MAPK phosphorylation, which results in inhibition of the PKD1/CREB/Bcl-2 survival pathway and triggers apoptosis. Finally, we established a colorectal cancer xenograft model and found that selenite treatment markedly inhibits tumour growth through the MAPK/PKD1/CREB/Bcl-2 pathway in vivo. Our results demonstrated that a supranutritional dose of selenite induced CRC cell apoptosis through inhibition of the PKD1/CREB/Bcl-2 axis both in vitro and in vivo.

Gargalionis AN, Korkolopoulou P, Farmaki E, et al.
Polycystin-1 and polycystin-2 are involved in the acquisition of aggressive phenotypes in colorectal cancer.
Int J Cancer. 2015; 136(7):1515-27 [PubMed] Related Publications
The polycystins PC1 and PC2 are emerging as major players in mechanotransduction, a process that influences all steps of the invasion/metastasis cascade. We hypothesized that PC1 and PC2 facilitate cancer aggressiveness. Immunoblotting, RT-PCR, semi-quantitative and quantitative real-time PCR and FACS analyses were employed to investigate the effect of polycystin overexpression in colorectal cancer (CRC) cells. The impact of PC1 inhibition on cancer-cell proliferation was evaluated through an MTT assay. In vitro data were analyzed by Student's t-test. HT29 human xenografts were treated with anti-PC1 (extracellular domain) inhibitory antibody and analyzed via immunohistochemistry to determine the in vivo role of PC1 in CRC. Clinical significance was assessed by examining PC1 and PC2 protein expression in CRC patients (immunohistochemistry). In vivo and clinical data were analyzed by non-parametric tests, Kaplan-Meier curves, log-rank test and Cox model. All statistical tests were two-sided. PC1 overexpression promotes epithelial-to-mesenchymal transition (EMT) in HCT116 cells, while PC2 overexpression results in upregulation of the mTOR pathway in SW480 cells. PC1 inhibition causes reduced cell proliferation in CRC cells inducing tumor necrosis and suppressing EMT in HT29 tumor xenografts. In clinical study, PC1 and PC2 overexpression associates with adverse pathological parameters, including invasiveness and mucinous carcinomas. Moreover, PC1 overexpression appears as an independent prognostic factor of reduced recurrence-free survival (HR = 1.016, p = 0.03) and lowers overall survival probability, while aberrant PC2 expression predicts poor overall survival (p = 0.0468). These results support, for the first time, a direct link between mechanosensing polycystins (PC1 and PC2) and CRC progression.

Chien YC, Chen JC, Lin WC, et al.
Using [¹⁸F]FBAU for imaging brain tumor progression in an F98/tk-luc glioma-bearing rat model.
Oncol Rep. 2014; 32(2):691-9 [PubMed] Related Publications
1-(2-Deoxy-2-[18F]fluoro-β-D-arabinofuranosyl)-5-bromouracil ([18F]FBAU), a substitute for thymine, has been reported as an effective reporter probe by which to trace cellular metabolism with its positron emission. In the present study, a rat xenograft model bearing F98 glioma transfected with dual reporter genes, herpes simplex virus type 1 thymidine kinase (HSV1-tk) and firefly luciferase (luc) was used for monitoring tumor progression by multimodalities of molecular imaging using [18F]FBAU and D-luciferase as probes. Rat F98 glioma cells were transfected with the pC1-tk-IRES-luc vectors. The selected stable clone was renamed as the F98/tk-luc cell line. Fischer 344 male rats bearing orthotropic F98/tk-luc gliomas in the left brain were used. On day 13 post tumor inoculation, biodistribution, positron emission tomography (PET), magnetic resonance imaging (MRI) and ex vivo autoradiography were performed. The surviving fraction of F98/tk-luc cells treated with 15 µM ganciclovir (GCV) was 15.9%, and the uptake of [131I]FIAU in these cells was significantly enhanced when compared with F98 cells. The correlation coefficient of tumor volume vs. the bioluminescence in the F98/tk-luc glioma-bearing rats was 0.90. The biodistribution showed that the accumulation ratios of [18F]FBAU for glioma-to-normal brain were 9.16, 14.24, 5.7 and 13.7 at 30, 60, 90 and 120 min post i.v. injection, respectively. Consistent tumor enhancement of [18F]FBAU/PET imaging was also noted from 30-90 min post injection. Ex vivo autoradiography also confirmed significant [18F]FBAU uptake in tumors. In conclusion, [18F]FBAU may be used as a PET probe for monitoring glioma progression in animal models and may have potential for clinical use as well.

Tan K, Cho SG, Luo W, et al.
KiSS1-induced GPR54 signaling inhibits breast cancer cell migration and epithelial-mesenchymal transition via protein kinase D1.
Curr Mol Med. 2014; 14(5):652-62 [PubMed] Related Publications
The metastasis suppressor protein Kisspeptin regulates cancer cell proliferation and motility through its receptor, GRP54. However, the critical downstream effectors remain unclear. In this study, we investigated GPR54 signaling in breast cancer cells. Kisspeptin stimulation caused a decrease in migration of multiple breast cancer cell lines. Also, Kisspeptin inhibited MDA-MB-231 cell colony formation in 3D matrigel culture and in soft agar. Kisspeptin treatment elevated phosphorylated PKD1 in a PKC-dependent manner. However, knockdown of either GPR54 or PKD1 increased breast cancer cell migration and invasion. Furthermore, GPR54 knockdown blocked Kisspeptin-induced phosphorylation of PKD1. Finally, Kisspeptin stimulation induced a PKD1 phosphorylation-dependent decrease in expression of Slug, a transcription factor that drives epithelial-mesenchymal transition (EMT), and a concomitant increase in E-cadherin expression. Therefore, KiSS1/GPR54 signaling through PKD1 acts to maintain the epithelial state and to inhibit breast cancer cell invasiveness, and exerts functions associated with its role as a metastasis suppressor.

Cnossen WR, Drenth JP
Polycystic liver disease: an overview of pathogenesis, clinical manifestations and management.
Orphanet J Rare Dis. 2014; 9:69 [PubMed] Free Access to Full Article Related Publications
Polycystic liver disease (PLD) is the result of embryonic ductal plate malformation of the intrahepatic biliary tree. The phenotype consists of numerous cysts spread throughout the liver parenchyma. Cystic bile duct malformations originating from the peripheral biliary tree are called Von Meyenburg complexes (VMC). In these patients embryonic remnants develop into small hepatic cysts and usually remain silent during life. Symptomatic PLD occurs mainly in the context of isolated polycystic liver disease (PCLD) and autosomal dominant polycystic kidney disease (ADPKD). In advanced stages, PCLD and ADPKD patients have massively enlarged livers which cause a spectrum of clinical features and complications. Major complaints include abdominal pain, abdominal distension and atypical symptoms because of voluminous cysts resulting in compression of adjacent tissue or failure of the affected organ. Renal failure due to polycystic kidneys and non-renal extra-hepatic features are common in ADPKD in contrast to VMC and PCLD. In general, liver function remains prolonged preserved in PLD. Ultrasonography is the first instrument to assess liver phenotype. Indeed, PCLD and ADPKD diagnostic criteria rely on detection of hepatorenal cystogenesis, and secondly a positive family history compatible with an autosomal dominant inheritance pattern. Ambiguous imaging or screening may be assisted by genetic counseling and molecular diagnostics. Screening mutations of the genes causing PCLD (PRKCSH and SEC63) or ADPKD (PKD1 and PKD2) confirm the clinical diagnosis. Genetic studies showed that accumulation of somatic hits in cyst epithelium determine the rate-limiting step for cyst formation. Management of adult PLD is based on liver phenotype, severity of clinical features and quality of life. Conservative treatment is recommended for the majority of PLD patients. The primary aim is to halt cyst growth to allow abdominal decompression and ameliorate symptoms. Invasive procedures are required in a selective patient group with advanced PCLD, ADPKD or liver failure. Pharmacological therapy by somatostatin analogues lead to beneficial outcome of PLD in terms of symptom relief and liver volume reduction.

Kim JH, Kim WS, Park C
PKD1 is critical for Epstein-Barr virus LMP1-induced protection of malignant B cells from cell death induced by rituximab.
Leuk Lymphoma. 2015; 56(1):194-201 [PubMed] Related Publications
Protein kinase D1 (PKD1 or PKCμ) is a serine/threonine kinase that contributes to malignant progression. Although B and T cells express multiple PKCs, modulation of PKC in association with EBV has not been evaluated. In this study we examined the effects of PKD1 as a cellular target of EBV latent membrane protein-1 (LMP1) on the response of malignant B cells to rituximab and doxorubicin. LMP1 up-regulated PKD1 in malignant B cells but not in T cells. Interestingly, LMP1 stabilized PKD1 protein through direct interaction, which contributed to the survival of malignant B cells. In the absence of PKD1, LMP1 was unable to up-regulate Mcl-1. Also, PH domain and activation loop of PKD1 was critical for LMP1-mediated cell survival. PKD1 knockdown was found to be an efficient strategy to overcome resistance caused by LMP1 expression. Therefore, PKD1 could be a molecular target for therapeutic intervention in EBV-associated B cell lymphoma treatment.

Cnossen WR, te Morsche RH, Hoischen A, et al.
Whole-exome sequencing reveals LRP5 mutations and canonical Wnt signaling associated with hepatic cystogenesis.
Proc Natl Acad Sci U S A. 2014; 111(14):5343-8 [PubMed] Free Access to Full Article Related Publications
Polycystic livers are seen in the rare inherited disorder isolated polycystic liver disease (PCLD) and are recognized as the most common extrarenal manifestation in autosomal dominant polycystic kidney disease. Hepatic cystogenesis is characterized by progressive proliferation of cholangiocytes, ultimately causing hepatomegaly. Genetically, polycystic liver disease is a heterogeneous disorder with incomplete penetrance and caused by mutations in PRKCSH, SEC63, PKD1, or PKD2. Genome-wide SNP typing and Sanger sequencing revealed no pathogenic variants in hitherto genes in an extended PCLD family. We performed whole-exome sequencing of DNA samples from two members. A heterozygous variant c.3562C > T located at a highly conserved amino acid position (p.R1188W) in the low density lipoprotein receptor-related protein 5 (LRP5) gene segregated with the disease (logarithm of odds score, 4.62) but was not observed in more than 1,000 unaffected individuals. Screening of LRP5 in a PCLD cohort identified three additional mutations in three unrelated families with polycystic livers (p.V454M, p.R1529S, and p.D1551N), again all undetected in controls. All variants were predicted to be damaging with profound structural effects on LRP5 protein domains. Liver cyst tissue and normal hepatic tissue samples from patients and controls showed abundant LRP5 expression by immunohistochemistry. Functional activity analyses indicated that mutant LRP5 led to reduced wingless signal activation. In conclusion, we demonstrate that germ-line LRP5 missense mutations are associated with hepatic cystogenesis. The findings presented in this study link the pathophysiology of PCLD to deregulation of the canonical wingless signaling pathway.

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