Research IndicatorsGraph generated 11 August 2015 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 11 August, 2015 using data from PubMed, MeSH and CancerIndex
Specific Cancers (5)
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).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
Search the Epigenomics database and view relevant gene tracks of samples.
Latest Publications: PERP (cancer-related)
In the present study, we investigated the anticancer effects of the mitochondrial inhibitors, metaiodobenzylguanidine (MIBG), metformin and phenformin. 131I-MIBG has been used for scintigraphic detection and the targeted radiotherapy of neuroblastoma (NB), a pediatric malignancy. Non-radiolabeled MIBG has been reported to be cytotoxic to NB cells in vitro and in vivo. However, the mechanisms behind its growth suppressive effects have not yet been fully elucidated. Metformin and phenformin are diabetes medications that are being considered in anticancer therapeutics. We investigated the anticancer mechanisms of action of MIBG and metformin in NB. Our data revealed that both drugs suppressed NB cell growth and that the combination drug treatment was more potent. MIBG reduced MYCN and MYC expression in MYCN-amplified and non-MYCN-amplified NB cells in a dose- and time-dependent manner. Metformin was less effective than MIBG in destabilizing MYC/MYCN. The treatment of NB cells with metformin or MIBG resulted in an increased expression of genes encoding biomarkers for favorable outcome in NB [(ephrin (EFN)B2, EFNB3, EPH receptor B6 (EPHB6), neurotrophic tyrosine kinase, receptor, type 1 (NTRK1), CD44 and Myc-interacting zinc finger protein (MIZ-1)] and tumor suppressor genes [(early growth response 1 (EGR1), EPH receptor A2 (EPHA2), growth arrest and DNA-damage-inducible, beta (GADD45B), neuregulin 1 (NRG1), TP53 apoptosis effector (PERP) and sel-1 suppressor of lin-12-like (C. elegans) (SEL1L)]. Accordingly, metformin and MIBG augmented histone H3 acetylation in these cells. Phenformin also exhibited histone modification and was more effective than metformin in destabilizing MYC/MYCN in NB cells. Our data suggest that the destabilization of MYC/MYCN by MIBG, metformin and phenformin and their effects on histone modification are important mechanisms underlying their anticancer effects.
Coenen EA, Zwaan CM, Reinhardt D, et al.Pediatric acute myeloid leukemia with t(8;16)(p11;p13), a distinct clinical and biological entity: a collaborative study by the International-Berlin-Frankfurt-Munster AML-study group.
Blood. 2013; 122(15):2704-13 [PubMed
] Free Access to Full Article Related Publications
In pediatric acute myeloid leukemia (AML), cytogenetic abnormalities are strong indicators of prognosis. Some recurrent cytogenetic abnormalities, such as t(8;16)(p11;p13), are so rare that collaborative studies are required to define their prognostic impact. We collected the clinical characteristics, morphology, and immunophenotypes of 62 pediatric AML patients with t(8;16)(p11;p13) from 18 countries participating in the International Berlin-Frankfurt-Münster (I-BFM) AML study group. We used the AML-BFM cohort diagnosed from 1995-2005 (n = 543) as a reference cohort. Median age of the pediatric t(8;16)(p11;p13) AML patients was significantly lower (1.2 years). The majority (97%) had M4-M5 French-American-British type, significantly different from the reference cohort. Erythrophagocytosis (70%), leukemia cutis (58%), and disseminated intravascular coagulation (39%) occurred frequently. Strikingly, spontaneous remissions occurred in 7 neonates with t(8;16)(p11;p13), of whom 3 remain in continuous remission. The 5-year overall survival of patients diagnosed after 1993 was 59%, similar to the reference cohort (P = .14). Gene expression profiles of t(8;16)(p11;p13) pediatric AML cases clustered close to, but distinct from, MLL-rearranged AML. Highly expressed genes included HOXA11, HOXA10, RET, PERP, and GGA2. In conclusion, pediatric t(8;16)(p11;p13) AML is a rare entity defined by a unique gene expression signature and distinct clinical features in whom spontaneous remissions occur in a subset of neonatal cases.
The persistence leukemia stem cells (LSCs) in chronic myeloid leukemia (CML) despite tyrosine kinase inhibition (TKI) may explain relapse after TKI withdrawal. Here we performed genome-wide transcriptome analysis of highly refined CML and normal stem and progenitor cell populations to identify novel targets for the eradication of CML LSCs using exon microarrays. We identified 97 genes that were differentially expressed in CML versus normal stem and progenitor cells. These included cell surface genes significantly upregulated in CML LSCs: DPP4 (CD26), IL2RA (CD25), PTPRD, CACNA1D, IL1RAP, SLC4A4, and KCNK5. Further analyses of the LSCs revealed dysregulation of normal cellular processes, evidenced by alternative splicing of genes in key cancer signaling pathways such as p53 signaling (e.g. PERP, CDKN1A), kinase binding (e.g. DUSP12, MARCKS), and cell proliferation (MYCN, TIMELESS); downregulation of pro-differentiation and TGF-β/BMP signaling pathways; upregulation of oxidative metabolism and DNA repair pathways; and activation of inflammatory cytokines, including CCL2, and multiple oncogenes (e.g., CCND1). These data represent an important resource for understanding the molecular changes in CML LSCs, which may be exploited to develop novel therapies for eradication these cells and achieve cure.
Kong CS, Cao H, Kwok S, et al.Loss of the p53/p63 target PERP is an early event in oral carcinogenesis and correlates with higher rate of local relapse.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2013; 115(1):95-103 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: PERP is a p53/p63-regulated gene encoding a desmosomal protein that plays a critical role in cell-cell adhesion and tumor suppression.
STUDY DESIGN: We evaluated PERP expression in different grades of oral dysplasia (34 cases) and at different stages of invasive squamous cell carcinoma (SCC), and correlated the latter with clinical outcome. A tissue microarray consisting of nondysplastic mucosa, carcinoma in situ, SCC, and nodal metastases from 33 patients with human papilloma virus-negative SCC was stained for PERP and E-cadherin.
RESULTS: Complete loss of PERP expression was associated with worse local control in patients with SCC. The 5-year local control rate was 91% for patients with partial PERP loss versus 31% for those with complete loss (P = .01).
CONCLUSIONS: This is the first study to show that loss of PERP expression correlates with the transition to SCC and with increased local relapse in patients with oral cavity SCC.
Proestling K, Hebar A, Pruckner N, et al.The Pro allele of the p53 codon 72 polymorphism is associated with decreased intratumoral expression of BAX and p21, and increased breast cancer risk.
PLoS One. 2012; 7(10):e47325 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: The TP53 Arg72Pro polymorphism encodes two p53 variants with different biochemical properties. Here we investigated the impact of this polymorphism on the expression of key p53 target genes in a panel of human breast carcinomas, breast cancer risk, and age at onset.
METHODOLOGY/PRINCIPAL FINDINGS: The Arg72Pro polymorphism was genotyped in 270 breast cancer patients and 221 control subjects. In addition, the Arg72Pro genotype of 116 breast tumors was determined, and correlated with intratumoral mRNA expression of TP53 and its key target genes MDM2, p21, BAX, and PERP, as quantified by qRT-PCR. We found a significantly increased breast cancer risk associated with the Pro-allele (per-allele odds ratio, 1.46; 95% confidence interval, 1.08-1.99), and a significantly later mean age at breast cancer onset for Pro/Pro patients (63.2±18 years) compared to Arg/Arg patients (58.2±15 years). The frequency of somatic TP53 inactivation was 25.4% in Arg/Arg, 20.9% in Arg/Pro, and 16.7% in Pro/Pro patients, which may reflect a higher selective pressure to mutate the Arg-allele. The median mRNA levels of p21 and BAX in the tumors of Pro-allele carriers were significantly reduced to 55.7% and 76.9% compared to Arg/Arg patients, whereas p53, MDM2 and PERP expression were hardly altered.
CONCLUSIONS/SIGNIFICANCE: The p53(72Arg) variant appears to be a more potent in vivo transcription factor and tumor suppressor in human breast cancer than the p53(72Pro) variant. The Arg72Pro genotype has no significant effects in patients with TP53 mutated tumors, in which p53 is non-functional.
Kowalewska M, Radziszewski J, Goryca K, et al.Estimation of groin recurrence risk in patients with squamous cell vulvar carcinoma by the assessment of marker gene expression in the lymph nodes.
BMC Cancer. 2012; 12:223 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: Regional lymph node (LN) status is a well-known prognostic factor for vulvar carcinoma (VC) patients. Although the reliable LN assessment in VC is crucial, it presents significant diagnostic problems. We aimed to identify specific mRNA markers of VC dissemination in the LN and to address the feasibility of predicting the risk of nodal recurrence by the patterns of gene expression.
METHODS: Sentinel and inguinal LN samples from 20 patients who had undergone surgery for stage T(1-3), N(0-2), M(0) primary vulvar squamous cell carcinoma were analyzed. Gene expression profiles were assessed in four metastatic [LN(+)] and four histologically negative [LN(-)] lymph node samples obtained from four VC patients, by the Affymetrix U133 Plus 2.0 gene expression microarrays. Of the set of genes of the highest expression in the metastatic LNs compared to LN(-), seven candidate marker genes were selected: PERP, S100A8, FABP5, SFN, CA12, JUP and CSTA, and the expression levels of these genes were further analyzed by the real-time reverse transcription polymerase chain reaction (qRT-PCR) in 71 LN samples.
RESULTS: All of the seven genes in question were significantly increased in LN(+) compared to LN(-) samples. In the initial validation of the seven putative markers of metastatic LN, the Cox proportional hazard model pointed to SFN, CA12 and JUP expression to significantly relate to the time to groin recurrence in VC patients.
CONCLUSIONS: Our findings first provided evidence that SFN, CA12 and JUP have a potential of marker genes for the prediction of the groin recurrence LN in VC patients.
Chen K, Luo Z, Li Z, et al.PERP gene therapy attenuates lung cancer xenograft via inducing apoptosis and suppressing VEGF.
Cancer Biol Ther. 2011; 12(12):1114-9 [PubMed
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Inducing apoptosis is an attractive antitumor strategy. PERP is an apoptosis-associated target of p53, and its activation alone is sufficient to induce apoptotic pathway leading to cell death. We have previously demonstrated that overexpression of PERP in tumor cell lines with low intrinsic PERP activity suppressed cancer cell growth and enhanced sensitivity to chemotherapeutical agents. We further identified that PERP was present in surgical normal lung tissue, but absent in cancerous tissue of the same patient. Here, we sought to investigate the anti-tumor effects of PERP gene therapy in vivo. Then nude mice were transplanted with p53-mutanted Anip973 human lung cancer xenografts and treated with normal saline, pcDNA3.1 (vector) and pcDNA3.1-PERP, respectively. Successful transfection and robust expression of PERP was detected. Treatment with pcDNA3.1-PERP increased apoptosis and retarded growth in the xenografts, which contributed to a 55% decrease in tumor volume compared with controls. Furthermore, PERP gene therapy activated pro-apoptotic Caspase-3 cascade and upregulated the expression of the second mitochondria-derived activator of caspase (Smac) and human TNF-related apoptosis-inducing ligand (TRAIL), while suppressed vascular endothelial growth factor (VEGF) expression, indicating apoptosis and anti-angiogenesis are involved in the inhibitory effect of the PERP gene therapy. Taken together, our results suggest PERP gene therapy may supply an alternative strategy for lung adenocarcinoma management. Furthermore, Anip973 is a p53-mutanted cell line and the findings of this study provide reference value for other p53-mutanted cancers which is common among malignant tumors.
Rao S, Welsh L, Cunningham D, et al.Correlation of overall survival with gene expression profiles in a prospective study of resectable esophageal cancer.
Clin Colorectal Cancer. 2011; 10(1):48-56 [PubMed
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PURPOSE: Preoperative chemotherapy has demonstrated a survival benefit for patients with potentially resectable esophageal cancer; however, currently it is not possible to predict the benefit of this treatment for an individual patient. This prospective study was designed to correlate gene expression profiles with clinical outcome in this setting.
PATIENTS AND METHODS: Eligible patients were deemed to have resectable disease after staging by computed tomography, endoscopic ultrasound, and laparoscopy as indicated and following discussion at the multidisciplinary team meeting. All patients received neoadjuvant platinum and fluoropyrimidine-based chemotherapy; and clinical data were entered prospectively onto a study-specific database. Total RNA was isolated from pretreatment tumor biopsies obtained at baseline endoscopy and analyzed using a cDNA array consisting of 22,000 cDNA clones.
RESULTS: Of the patients with adequate follow-up accrued between 2002 and 2005, 35 satisfied the quality control measures for the microarray profiling. Median follow-up was 938 days. Supervised hierarchical clustering of normalized data revealed 165 significantly differentially expressed genes based on overall survival (OS; P < .01) with 2 distinct clusters: a poor outcome group: N = 17 (1 year OS 46.2%) and a good outcome group: N = 18 (1 year OS 100%). Genes identified included those previously associated with esophageal cancer and, interestingly, a group of genes encoding proteins involved in the regulation of the TOLL receptor-signaling pathway.
CONCLUSION: This initial study has highlighted groups of tumors with distinct gene expression profiles based on survival and warrants further validation in a larger cohort. This approach may further our understanding of individual tumor biology and thus facilitate the development of tailored treatment.
The activation and regulation of target genes by the tumour-suppressor p53 dictates the fate of a cell, with cell cycle arrest or apoptosis being two distinct outcomes. PERP (p53 apoptosis effector related to PMP-22), a p53 transcriptional target, is induced specifically during apoptosis but not cell cycle arrest. Downregulation of PERP is associated with the aggressive, monosomy 3-type of uveal melanoma (UM), the most common primary intraocular tumour in adults, and increased PERP expression has a pro-apoptotic effect in UM cells. Here, we identify a novel effect of PERP expression, as elevated PERP protein positively influences active levels of its own transcriptional regulator, p53. Using fluorescent fusion proteins of PERP, p53 and MDM2, we demonstrate in single living UM cells that PERP expression significantly enhances p53 activity and its nuclear localization, increases p53-dependent transcription (including that of MDM2) while allowing oscillatory nucleo-cytoplasmic shuttling of p53/MDM2 complexes. Phosphorylation of p53 serine residues that interfere with the interaction between p53 and its negative regulator MDM2 and enhance pro-apoptotic gene transcription also occurs subsequent to PERP expression. These results implicate a role for PERP in amplifying functional p53 levels that promote p53-dependent apoptosis, and reveal a potential target for exploitation in enhancing p53 activity.
How genetic variations in apoptosis pathway interact with environmental factors to contribute to esophageal adenocarcinoma (EA) risk has not been comprehensively investigated. We conducted a case-only analysis in 335 Caucasian EA patients that were genotyped for 242 single nucleotide polymorphisms (SNPs) in 43 apoptotic genes. Gene-environment interactions were assessed using a two-step approach. First, random forest algorithm was used to screen for the potential interacting markers. Next, we used case-only logistic regression model to estimate the effects of gene-environment interactions on EA risk. Four SNPs (PERP rs648802; PIK3CA rs4855094, rs7644468 and TNFRSF1A rs4149579) had significant interaction with gastroesophageal reflux disease (GERD). The presence of variant alleles in TP53BP1 rs560191, CASP7 rs7907519 or BCL2 rs12454712 enhanced the risk of smoking by 2.08-2.58 times [interaction odds ratio (ORi)=2.08-2.58, adjusted P-value (Padj)=0.02-0.04]. Compared with patients carrying ≤1 risk genotype, the risk of GERD on EA was increased in persons with two (ORi=1.89, Padj=0.016) or ≥3 (ORi=4.30, Padj<0.0001) risk genotypes. Compared with cases with ≤1 risk genotype, smoking-associated EA risk increased by 3.15 times when ≥2 risk genotypes were present (ORi=3.15, Padj<0.0001). In conclusion, interactions among apoptotic SNPs and GERD or smoking play an important role in EA development.
Dysregulated cell-cell adhesion plays a critical role in epithelial cancer development. Studies of human and mouse cancers have indicated that loss of adhesion complexes known as adherens junctions contributes to tumor progression and metastasis. In contrast, little is known regarding the role of the related cell-cell adhesion junction, the desmosome, during cancer development. Studies analyzing expression of desmosome components during human cancer progression have yielded conflicting results, and therefore genetic studies using knockout mice to examine the functional consequence of desmosome inactivation for tumorigenesis are essential for elucidating the role of desmosomes in cancer development. Here, we investigate the consequences of desmosome loss for carcinogenesis by analyzing conditional knockout mice lacking Perp, a p53/p63 regulated gene that encodes an important component of desmosomes. Analysis of Perp-deficient mice in a UVB-induced squamous cell skin carcinoma model reveals that Perp ablation promotes both tumor initiation and progression. Tumor development is associated with inactivation of both of Perp's known functions, in apoptosis and cell-cell adhesion. Interestingly, Perp-deficient tumors exhibit widespread downregulation of desmosomal constituents while adherens junctions remain intact, suggesting that desmosome loss is a specific event important for tumorigenesis rather than a reflection of a general change in differentiation status. Similarly, human squamous cell carcinomas display loss of PERP expression with retention of adherens junctions components, indicating that this is a relevant stage of human cancer development. Using gene expression profiling, we show further that Perp loss induces a set of inflammation-related genes that could stimulate tumorigenesis. Together, these studies suggest that Perp-deficiency promotes cancer by enhancing cell survival, desmosome loss, and inflammation, and they highlight a fundamental role for Perp and desmosomes in tumor suppression. An understanding of the factors affecting cancer progression is important for ultimately improving the diagnosis, prognostication, and treatment of cancer.
Mundt HM, Stremmel W, Melino G, et al.Dominant negative (DeltaN) p63alpha induces drug resistance in hepatocellular carcinoma by interference with apoptosis signaling pathways.
Biochem Biophys Res Commun. 2010; 396(2):335-41 [PubMed
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p63 belongs to the family of p53-related transcription factors expressing a variety of isoforms. The Trp63 gene has two promoters that drive the expression of two major p63 isoform subfamilies. Isoforms of the TAp63 subfamily show pro-apoptotic activities, whereas members of the N-terminally truncated (DeltaN) p63 subfamily have anti-apoptotic functions. We have previously shown an important role for TAp63alpha in the induction of apoptosis and chemosensitivity of hepatocellular carcinoma (HCC). Here, we investigated the molecular mechanisms accounting for the oncogenic role of DeltaNp63alpha in HCC. DeltaNp63alpha can directly interfere with the transcriptional activation function of the TA (containing the transactivation domain) isoforms of the p53 family and consequently inhibit transactivation of pro-apoptotic target genes. DeltaNp63alpha negatively regulates the genes encoding for the death receptor CD95 and the pro-apoptotic Bcl-2 family member BAX. Thus, DeltaNp63alpha expression in HCC interferes with both the death receptor and the mitochondrial apoptosis activity of the TA isoforms. In addition and of clinical relevance, DeltaNp63alpha inhibits activation of p53 family target genes and apoptosis induced by chemotherapeutic drugs. Chemotherapeutic treatment induces expression of Bax, Bim, Noxa, Puma and Perp; this is antagonized by DeltaNp63alpha. Our data suggest that the DeltaNp63alpha isoform represses apoptosis-related genes of the extrinsic and intrinsic apoptosis signaling pathways, thereby contributing to chemoresistance of HCC.
The mechanism by which gastroesophageal reflux promotes metaplasia→dysplasia→carcinoma is unknown. The aim of the study is to determine if repeated exposure to acid and bile confers a tumorigenic phenotype in a telomerase (hTERT)-immortalized benign Barrett's cell line (BAR-T). BAR-T cells were exposed to acid (pH 4) (A) and bile salt (200 μM glycochenodeoxycholic acid) (B) daily for 5 min up to 65+ weeks. The control cells were grown in parallel without any A or B treatment. Cell morphology, proliferation, transformation, and molecular changes in the gene expression for COX-2, TC22, p53 and p53 target genes were analyzed at 8-12 weeks intervals. At 46 weeks BAR-T cells exposed to (A+B) showed distinct phenotypic changes: forming clusters and acini, and at 65 weeks displayed foci in monolayer, and formed distinct colonies in soft agar. Untreated cells did not show any such changes. In A+B-treated BAR-T cells, COX-2 mRNA increased 10- to 20-fold, TC22 mRNA increased by 2- to 3-fold at 22-65 weeks, p53, MDM2, PERP, and p21mRNA increased 2.5-, 6.4-, 4-, and 2.6-fold respectively when compared to untreated cells at 34 weeks. However, at 58 weeks onward, there was a sharp decline of p53 and its target genes to the baseline level. At 65 weeks A+B-treated BAR-T cells formed tumor in nude mice whereas untreated cells did not. We demonstrate a novel in vitro model of transformation of a benign Barrett's cell line following repeated exposure to A+B over the course of 65 weeks.
Yarden RI, Friedman E, Metsuyanim S, et al.Single-nucleotide polymorphisms in the p53 pathway genes modify cancer risk in BRCA1 and BRCA2 carriers of Jewish-Ashkenazi descent.
Mol Carcinog. 2010; 49(6):545-55 [PubMed
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Germline mutations in the BRCA1 and BRCA2 genes are associated with a significantly increased lifetime risk for developing breast and/or ovarian cancer. However, incomplete penetrance and substantial variability in age of disease onset among carriers of the same mutation suggests the involvement of additional modifier genes and/or environmental factors. Somatic inactivating mutations in the p53 gene and genes of the p53 pathway often accompany BRCA1/2-associated tumors. Therefore, we assessed whether these genes are modifiers of penetrance. We genotyped Jewish-Ashkenazi women for functional single-nucleotide polymorphisms (SNPs) in the AKT1 (C>T rs3730358) and the PERP (C>T rs2484067) genes that affect p53-mediated apoptosis, as well as two tag-SNPs in the CHEK2 (C>T rs743184) and the ZBRK1/ZNF350 (G>A rs2278414) genes that encode for proteins involved in growth arrest following DNA damage. The study population included 138 healthy women, 148 breast/ovarian cancer BRCA1/2 mutation carriers, 121 asymptomatic BRCA1/2 mutation carriers, and 210 sporadic noncarrier breast cancer patients. Utilizing lambda(2) and Kaplan-Meier analysis revealed a hazard ratio (HR) of 3.23 (95% CI: 1.44-54, P = 0.0184) for the TT genotype of AKT (rs3730358), HR = 2.105 (95% CI: 1.049-7.434, P = 0.039) for CHEK2 CC genotype (rs743184), and HR = 2.4743 (95% CI: 1.205-11.53, P = 0.022) for the AG genotype of ZBRK1/ZNF350 (rs2278414). No significant association between PERP variants and cancer was identified HR = 0.662 (95% CI: 0.289-1.324, P = 0.261). Our results suggest that genes that act upstream of p53, or participate in the DNA damage response, may modify the risk of cancer in women with mutant BRCA1/2 alleles.
Jiang H, Xia J, Kang J, et al.Short hairpin RNA targeting beta-catenin suppresses cell proliferation and induces apoptosis in human gastric carcinoma cells.
Scand J Gastroenterol. 2009; 44(12):1452-62 [PubMed
] Related Publications
OBJECTIVE: Aberrant activation of Wnt/beta-catenin signaling is involved in various cancers, including human gastric cancer. Here we investigate the role of Wnt/beta-catenin signaling in regulating gastric cancer cell apoptosis.
MATERIAL AND METHODS: Expression of beta-catenin was investigated after transfection with beta-catenin short hairpin RNA (shRNA) in gastric cancer cells by Western blotting and immunofluorescence analysis. beta-catenin/T-cell factor transcriptional activity was also investigated by using a luciferase reporter assay. Next, the effects of beta-catenin shRNA on cell proliferation and apoptosis were evaluated by the 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide assay and flow cytometric analysis. To investigate the precise mechanism of these effects, a comprehensive analysis was performed using a cDNA microarray.
RESULTS: shRNA targeting beta-catenin resulted in a significant decrease in beta-catenin expression, and its nuclear localization and cell proliferation. Meanwhile, increased cell apoptosis was confirmed. The comprehensive analysis showed that shRNA targeting beta-catenin upregulated 26 apoptosis-related genes (including PERP, TRAF3, PDCD2, TNFRSF25, AKT2 and YWHAZ) and downregulated 48 apoptosis-related genes (including MALT1, IRAK1, TNFAIP3, PPP1R13L, TRIP and YWHAB) in gastric cancer cells. Pathway analysis suggested that the nuclear factor-kappaB pathway was involved in beta-catenin knockdown-induced apoptosis.
CONCLUSIONS: Attenuation of beta-catenin by shRNA resulted in suppressed cell proliferation and apparent apoptosis, suggesting that beta-catenin may be a target for therapy of gastric cancer.
Amano T, Nakamizo A, Mishra SK, et al.Simultaneous phosphorylation of p53 at serine 15 and 20 induces apoptosis in human glioma cells by increasing expression of pro-apoptotic genes.
J Neurooncol. 2009; 92(3):357-71 [PubMed
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Understanding the mechanism underlying p53's ability to induce cell cycle arrest versus apoptosis is critical to treating human gliomas, 70% of which contain wild-type p53. Although N-terminal phosphorylation results in activation of p53, the role of N-terminal phosphorylation, particularly at serines 15 and 20, in p53's ability to induce cell cycle arrest versus apoptosis remains controversial. Here we test the hypothesis that phosphorylation of serine 15 and/or 20 is causally related to p53-mediated apoptosis in human gliomas. Introduction of p53 plasmids containing alanine mutations at serine 15 or/and serine 20 (which block phosphorylation) or aspartate mutations (which mimic phosphorylation) at the same sites, implicated simultaneous phosphorylation of both sites in the induction of apoptosis. When a double phosphorylation-mimicking adenoviral p53 vector (Ad-p53-15D20D) was compared with an unphosphorylated p53 vector (Ad-p53), treatment with Ad-p53 resulted in G1-arrest, whereas Ad-p53-15D20D induced apoptosis. These effects occurred independent of phosphorylation of other N-terminal serine (i.e., serines 6, 9, 33, 37, 46) indicating that phosphorylation of S15 and S20 is sufficient for inducing apoptosis. Mechanistically, Ad-p53 was capable only of increasing the expression of p21/CIP, whereas Ad-p53-15D20D increased the binding to and expression of the pro-apoptotic genes Fas, Puma and PIG3. However, Ad-p53-15D20D did not alter the expression of Noxa, Bid, IGFBP3, PERP and Killer/DR5, suggesting that phosphorylation of S15 and S20 resulted in the expression of specific pro-apoptotic gene. In conclusion, simultaneous phosphorylation of S15 and S20 is causally associated with apoptosis, resulting in increased expression of specific p53-responsive pro-apoptotic genes.
Davies L, Gray D, Spiller D, et al.P53 apoptosis mediator PERP: localization, function and caspase activation in uveal melanoma.
J Cell Mol Med. 2009; 13(8B):1995-2007 [PubMed
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p53 apoptosis effector related to PMP-22 (PERP) is a transcriptional target gene of p53 tumour suppressor that is specifically induced during apoptosis and not during cell cycle arrest. In primary uveal melanoma (UM), the most common intraocular malignancy in adults that has a reportedly unaffected signalling pathway upstream of and including p53, PERP expression is down-regulated in the metastatic monosomy 3-type tumours, compared with the less aggressive disomy 3-type tumours. Here, we demonstrate experimentally, by the use of full-length PERP-green fluorescent protein (GFP) fusions and real-time confocal microscopy, the intracellular targeting and plasma membrane localization of PERP in living UM cells and show that expression of PERP induces caspase-mediated apoptosis in UM cells. Induction of PERP expression in GFP-PERP-transfected UM cells leads to increased levels of cleaved caspase-8 forms, as well as to reduction of its full-length substrate Bid, but not to detectable processing of caspase-9. The levels of mature caspase-8, -9 and -3 proteins significantly correlate with PERP expression levels in primary UMs. Transcriptional profiling of PERP and caspase-8 in tumour specimens indicates that the positive association of PERP and caspase-8 proteins is a consequence of post-translational processing, most likely at the level of caspase-8 cleavage, and not of increased transcription of pro-caspase-8. We conclude that PERP expression leads to activation of an extrinsic receptor-mediated apoptotic pathway, with a possible subsequent engagement of the intrinsic apoptotic pathway. The findings underline the apoptotic pathway mediated by PERP as a critical mechanism employed by UM tumours to modulate susceptibility to apoptosis.
Ross CW, Ouillette PD, Saddler CM, et al.Comprehensive analysis of copy number and allele status identifies multiple chromosome defects underlying follicular lymphoma pathogenesis.
Clin Cancer Res. 2007; 13(16):4777-85 [PubMed
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PURPOSE: Follicular lymphoma (FL) constitutes the second most common non-Hodgkin's lymphoma in the Western world. The clinical course is variable and only in part explained by known tumor-intrinsic or -extrinsic factors. FL carries the hallmark chromosomal translocation t(14;18), deregulating the expression of Bcl-2, but this is not sufficient to explain either FL biology or clinical behavior.
EXPERIMENTAL DESIGN: We have employed high-density genomic profiling technology using the Affymetrix 50K-XbaI oligonucleotide single nucleotide polymorphism-chip platform to interrogate the genomes of 58 fluorescence-activated cell-sorted (FACS) FL specimens for chromosomal copy number changes and 46 specimens for loss of heterozygosity (LOH).
RESULTS: We report (a) previously unknown high-frequency copy-neutral LOH (uniparental disomy) in FL on chromosomes 1p (approximately 50%) and 6p (approximately 30%); (b) that del6q is complex, as reported, with at least two regions of minimal common loss at 6q13-15 and 6q23-24, and that in addition, approximately 8% of FL specimens contain a homozygous deletion at 6q23.3-24.1 that spans the negative NFkappaB regulator A20 and the p53 apoptosis effector PERP; (c) that combined analysis of chromosome 17p for LOH, copy number, and p53 mutations shows that most p53 mutations in FL do not involve del17p. Finally, we map high-frequency LOH with and without copy loss on chromosomes 9p, 10q, and 16p and genomic gains on 2p15-16 and 8q24.22-24.3.
CONCLUSIONS: This comprehensive description of the pathologic anatomy of the FL genome uncovers novel genetic lesions and should aid with identification of genes relevant to FL biology and clinical behavior.
Tumour-derived p53 mutants are thought to have acquired 'gain-of-function' properties that contribute to oncogenicity. We have tested the hypothesis that p53 mutants suppress p53-target gene expression, leading to enhanced cellular growth. Silencing of mutant p53 expression in several human cell lines was found to lead to the upregulation of wild-type p53-target genes such as p21, gadd45, PERP and PTEN. The expression of these genes was also suppressed in H1299-based isogenic cell lines expressing various hot-spot p53 mutants, and silencing of mutant p53, but not TAp73, abrogated the suppression. Consistently, these hot-spot p53 mutants were able to suppress a variety of p53-target gene promoters. Analysis using the proto-type p21 promoter construct indicated that the p53-binding sites are dispensable for mutant p53-mediated suppression. However, treatment with the histone deacetylase inhibitor trichostatin-A resulted in relief of mutant p53-mediated suppression, suggesting that mutant p53 may induce hypo-acetylation of target gene promoters leading to the suppressive effects. Finally, we show that stable down-regulation of mutant p53 expression resulted in reduced cellular colony growth in human cancer cells, which was found to be due to the induction of apoptosis. Together, the results demonstrate another mechanism through which p53 mutants could promote cellular growth.
Paraoan L, Gray D, Hiscott P, et al.Expression of p53-induced apoptosis effector PERP in primary uveal melanomas: downregulation is associated with aggressive type.
Exp Eye Res. 2006; 83(4):911-9 [PubMed
] Related Publications
Expression of PERP (p53 apoptosis effector related to PMP-22) was investigated in primary uveal melanomas and its variation was analyzed in relation to clinico-pathological and cytogenetical characteristics of these tumors. The transcriptional level of PERP gene was measured by quantitative real-time RT-PCR in 26 uveal melanomas with known chromosomes 3 and 8 status. PERP protein levels were assessed by Western blot analysis of 22 fresh-frozen tumors and by immunohistochemical analysis of 16 paraffin-embedded tumor specimens. Differential expression of PERP was identified in primary choroidal melanoma specimens, both at transcriptional and protein level. Reduced PERP mRNA level was significantly associated with monosomy 3 (two-way ANOVA and t-test, p=0.004) but not with gains in chromosome 8. Transcriptional downregulation of PERP did not present a statistically significant association with ciliary body involvement, size, PAS-positive loops or cell type. Immunoblotting and immunohistochemistry further demonstrated significantly reduced PERP protein level in monosomy 3 melanomas, as compared with disomy 3 tumors. The altered expression of PERP highlighted this apoptosis-specific target of p53 as a possible contributor to apoptosis in uveal melanoma with PERP downregulation being particularly relevant to the aggressive (monosomy 3) type of uveal melanoma. As PERP is a novel type of p53 effector that is likely to stimulate apoptosis through a mechanism distinct from that of Bcl-2-related mitochondrial effectors, further elucidation of its role in uveal melanoma pathogenesis will assist in the design of novel therapeutic approaches aimed at increasing the rate of apoptosis in this tumor.
Luthra R, Wu TT, Luthra MG, et al.Gene expression profiling of localized esophageal carcinomas: association with pathologic response to preoperative chemoradiation.
J Clin Oncol. 2006; 24(2):259-67 [PubMed
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PURPOSE: Patients with localized esophageal carcinoma have a 5-year survival rate of less than 20%. Patients are often treated similarly (ie, with preoperative chemoradiotherapy) but the outcomes vary greatly. Chemoradiotherapy and surgery can result in significant undesirable consequences. Currently, however, there are no tools to help select optimum therapy. We hypothesized that gene expression profiling could provide clues and biomarkers for selection of therapy.
METHODS: Pretreatment endoscopic cancer biopsies from 19 patients (16 with adenocarcinoma, two with squamous cell carcinoma, and one with adenosquamous carcinoma) enrolled onto a preoperative chemoradiotherapy protocol were profiled using oligonucleotide microarrays. Surgical specimens following therapy were assessed for the degree of pathologic response. On the basis of array data, selected genes were analyzed by polymerase chain reaction.
RESULTS: Unsupervised hierarchical cluster analysis segregated the cancers into two molecular subtypes, each consisting 10 and nine specimens, respectively. Most cancers (five of six) that had pathologic complete response (pathCR) clustered in molecular subtype I. Subtype II, with one exception, consisted cancers that had less than pathCR (< pathCR). Using a combination marker approach, levels of PERP, S100A2, and SPRR3 allowed discrimination of pathCR from < pathCR with high sensitivity and specificity (85%). Pathway analysis identified apoptotic pathway as one of the key functions downregulated in molecular type II in comparison with type I.
CONCLUSION: These encouraging, albeit preliminary, data suggest that expression profiling may distinguish cancers with different pathologic outcome. This is the first report to show subtypes of esophageal cancers with distinct molecular signatures. The potential of PERP, S100A2, and SPRR3 as biomarkers of pathCR warrants further validation.
Salvatore G, Beers R, Margulies I, et al.Improved cytotoxic activity toward cell lines and fresh leukemia cells of a mutant anti-CD22 immunotoxin obtained by antibody phage display.
Clin Cancer Res. 2002; 8(4):995-1002 [PubMed
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Recombinant immunotoxins are fusion proteins composed of the Fv domains of antibodies fused to bacterial or plant toxins that are being developed for the targeted therapy of cancer. RFB4 (Fv)-Pseudomonas exotoxin 38 (PE38) is an immunotoxin that targets CD22 expressed on B cells and B-cell malignancies. A disulfide-stabilized form of RFB4 (Fv)-PE38 is being evaluated in a Phase I clinical trial. The aim of the present study was to improve the activity of RFB4 (Fv)-PE38 to more effectively treat patients with leukemias and lymphomas. To increase the affinity of RFB4 (Fv), we used the techniques of phage display and hot spot mutagenesis. We identified mutational hot spot sequences in heavy chain complementary determining region 3 (V(H) CDR3) and randomized these in a phage display library. Mutant phages were panned on CD22-positive Daudi cells. A variety of mutant Fvs were obtained, and the corresponding immunotoxins were prepared. Several mutant immunotoxins with increased binding affinity and cytotoxic activity were obtained. The most active immunotoxin contained amino acid residues Thr-His-Trp (THW) in place of Ser-Ser-Tyr (SSY) at positions 100, 100A, and 100B of the Fv and had an affinity improved from 85 nM to 6 nM. The THW mutant had a 5- to 10-fold increase in activity on various CD22-positive cell lines and was up to 50 times more cytotoxic to cells from patients with chronic lymphocytic leukemia and hairy-cell leukemia.
Hildebrandt T, van Dijk MC, van Muijen GN, Weidle UHLoss of heterozygosity of gene THW is frequently found in melanoma metastases.
Anticancer Res. 2001 Mar-Apr; 21(2A):1071-80 [PubMed
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We have recently described a new member of the PMP22/gas3 family of plasma membrane proteins referred to as THW. This gene is located on chromosome 6q and preliminary data have indicated a possible tumor suppressor gene function. We have therefore investigated LOH for gene THW in a panel of cancer cell lines and in a series of primary human melanomas as well as in melanoma metastases. We have detected LOH for gene THW in cell lines derived from melanoma, breast, pancreas, cervical, prostate and colon carcinoma with different prevalence, whereas the ovary carcinoma cell lines (n = 3) were negative. For melanomas we found a prevalence of LOH for gene THW of 10-20% in primary tumors, whereas in melanoma metastases we found a score of 50%. These data and the fact that the recently identified murine homologue PERP of gene THW mediates cell death in murine fibroblasts support the possible tumor suppressor function of gene THW.
Hildebrandt T, Preiherr J, Tarbé N, et al.Identification of THW, a putative new tumor suppressor gene.
Anticancer Res. 2000 Sep-Oct; 20(5A):2801-9 [PubMed
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Differential Display between metastasizing and non-metastasizing human melanoma cell lines NMCL-1 and 530 led to the identification of a putative transmembrane receptor, designated as THW, which is down-regulated in the metastasizing cell line. THW is composed of 193 aa, exhibits four putative transmembrane domains and does not reveal any homology to other proteins. Down-regulation of THW is correlated with metastatic capacity of melanoma cell lines. THW was down-regulated in mammary carcinoma cell lines compared with cell lines derived from non-malignant mammary epithelium, in pancreas cell lines derived from metastases compared with a cell line derived from a primary tumor and in several tumor tissues compared with normal tissues. The function of THW as a tumor suppressor is emphasized by the location of the THW gene on chromosome 6q. LOH for this region has been reported in malignant melanoma and prostate, pancreas, uterine and mammary carcinomas.
Mayer KM, Ansotegui IJ, Ballhausen WGThe human lck cDNA clone YT16 is a transforming oncogene.
Anticancer Res. 1992 Mar-Apr; 12(2):485-8 [PubMed
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The lck gene belongs to the src gene family and it is implicated in processes of lymphomagenesis. A full-:length lck-encoding cDNA clone, termed YT16 was isolated from a subtractive cDNA library, which was specific for expressed genes of the human Jurkat T-cell lymphoma. Sequence analysis of this molecular clone revealed major structural alterations compared to other tyrosine kinases classified as src-related genes. Firstly, a region within thw YT16 sequence surrounding the conserved ATP-binding site was modified by several short frameshift mutations. Secondly, the regulatory important tyrosine-505 residue was substituted by a threonine at this aligned position. The latter mutation was expected to result in a constitutional hypophosphorylated and thus permanently activated protein tyrosine kinase. These significant genetic alterations within the coding region of YT16 prompted us to investigate its biological relevance in vivo. To this end, we expressed YT16-specific sequences in NIH 3T3 fibroblasts and looked for morphological transformation of transfected cells. Here we report, that transformation of NIH 3T3 cells is obtained, provided that inhibitory untranslated sequences are removed from the YT16 cDNA clone. These results lend support to the notion, that structurally altered lck genes, in this study represented by the YT16 clone, may contribute to neoplastic processes in lymphoid cells.