Mithramycin Depletes Specificity Protein 1 and Activates p53 to Mediate Senescence and Apoptosis of Malignant Pleural Mesothelioma Cells

PURPOSE

Specificity protein 1 (SP1) is an oncogenic transcription factor overexpressed in various human malignancies. This study sought to examine SP1 expression in malignant pleural mesotheliomas (MPM) and ascertain the potential efficacy of targeting SP1 in these neoplasms.

EXPERIMENTAL DESIGN

qRT-PCR, immunoblotting, and immunohistochemical techniques were used to evaluate SP1 expression in cultured MPM cells and MPM specimens and normal mesothelial cells/pleura. MTS, chemotaxis, soft agar, β-galactosidase, and Apo-BrdUrd techniques were used to assess proliferation, migration, clonogenicity, senescence, and apoptosis in MPM cells following SP1 knockdown, p53 overexpression, or mithramycin treatment. Murine subcutaneous and intraperitoneal xenograft models were used to examine effects of mithramycin on MPM growth in vivo. Microarray, qRT-PCR, immunoblotting, and chromatin immunoprecipitation techniques were used to examine gene expression profiles mediated by mithramycin and combined SP1 knockdown/p53 overexpression and correlate these changes with SP1 and p53 levels within target gene promoters.

RESULTS

MPM cells and tumors exhibited higher SP1 mRNA and protein levels relative to control cells/tissues. SP1 knockdown significantly inhibited proliferation, migration, and clonogenicity of MPM cells. Mithramycin depleted SP1 and activated p53, dramatically inhibiting proliferation and clonogenicity of MPM cells. Intraperitoneal mithramycin significantly inhibited growth of subcutaneous MPM xenografts and completely eradicated mesothelioma carcinomatosis in 75% of mice. Mithramycin modulated genes mediating oncogene signaling, cell-cycle regulation, senescence, and apoptosis in vitro and in vivo. The growth-inhibitory effects of mithramycin in MPM cells were recapitulated by combined SP1 knockdown/p53 overexpression.

CONCLUSIONS

These findings provide preclinical rationale for phase II evaluation of mithramycin in patients with mesothelioma.

TRIM59 Promotes the Proliferation and Migration of Non-Small Cell Lung Cancer Cells by Upregulating Cell Cycle Related Proteins

TRIM protein family is an evolutionarily conserved gene family implicated in a number of critical processes including inflammation, immunity, antiviral and cancer. In an effort to profile the expression patterns of TRIM superfamily in several non-small cell lung cancer (NSCLC) cell lines, we found that the expression of 10 TRIM genes including TRIM3, TRIM7, TRIM14, TRIM16, TRIM21, TRIM22, TRIM29, TRIM59, TRIM66 and TRIM70 was significantly upregulated in NSCLC cell lines compared with the normal human bronchial epithelial (HBE) cell line, whereas the expression of 7 other TRIM genes including TRIM4, TRIM9, TRIM36, TRIM46, TRIM54, TRIM67 and TRIM76 was significantly down-regulated in NSCLC cell lines compared with that in HBE cells. As TRIM59 has been reported to act as a proto-oncogene that affects both Ras and RB signal pathways in prostate cancer models, we here focused on the role of TRIM59 in the regulation of NSCLC cell proliferation and migration. We reported that TRIM59 protein was significantly increased in various NSCLC cell lines. SiRNA-induced knocking down of TRIM59 significantly inhibited the proliferation and migration of NSCLC cell lines by arresting cell cycle in G2 phase. Moreover, TRIM59 knocking down affected the expression of a number of cell cycle proteins including CDC25C and CDK1. Finally, we knocked down TRIM59 and found that p53 protein expression levels did not upregulate, so we proposed that TRIM59 may promote NSCLC cell growth through other pathways but not the p53 signaling pathway.

β-Arrestin-1 protects against endoplasmic reticulum stress/p53-upregulated modulator of apoptosis-mediated apoptosis via repressing p-p65/inducible nitric oxide synthase in portal hypertensive gastropathy

Portal hypertensive gastropathy (PHG) is a serious cause of bleeding in patients, and is associated with portal hypertension. β-Arrestins (β-arrestin-1 and β-arrestin-2) are well-established mediators of endocytosis of G-protein-coupled receptors (GPCRs), ubiquitination, and G-protein-independent signaling. The role of β-arrestin-1 (β-arr1) in mucosal apoptosis in PHG remains unclear. The aim of this study was to investigate the involvement of β-arr1 in PHG via its regulation of endoplasmic reticulum (ER) stress/p53-upregulated modulator of apoptosis (PUMA) apoptotic signaling. Gastric mucosal injury and apoptosis were studied in PHG patients and in PHG mouse models. The induction of β-arr1 and the ER stress/PUMA signaling pathway were investigated, and the mechanisms of β-arr1-regulated gastric mucosal apoptosis were analyzed in vivo and in vitro experiments. β-arr1 and ER stress/PUMA signaling elements were markedly induced in the gastric mucosa of PHG patients and mouse models. Blockage of ER stress demonstrably attenuated the mucosal apoptosis of PHG, while targeted deletion of β-arr1 significantly aggravated the injury and ER stress/PUMA-mediated apoptosis. β-arr1 limited the activation of p65 to repress TNF-α-induced inducible nitric oxide synthase (iNOS) expression and NO release, which could regulate ER stress/PUMA-mediated mucosal apoptosis in PHG. In vivo and in vitro experiments further demonstrated that β-arr1 protected against mucosal apoptosis by repressing TNF-α-induced iNOS expression via inhibiting the activation of p65. These results indicated that β-arr1 regulated ER stress/PUMA-induced mucosal epithelial apoptosis through suppression of the TNF-α/p65/iNOS signaling pathway activation and that β-arr1 is a potential therapeutic target for PHG.

The expression of PD-L1 APE1 and P53 in hepatocellular carcinoma and its relationship to clinical pathology

OBJECTIVE

To study the expression of programmed death-ligand1 (PD-L1) in hepatocellular carcinoma and its relationship with clinicopathological characteristics and, prognosis of hepatocellular carcinoma and APE1, P53 protein expression levels.

PATIENTS AND METHODS

A total of 128 patients with hepatocellular carcinoma were enrolled in this study. The expression of PD-L1, APE1 and P53 were detected by immunohistochemistry.Use immunohistochemical ABC staining method to detect the expression levels of PD-L1, APE1 and P53 protein in the hepatocellular carcinoma of 128 cases.

RESULTS

Positive The positive expression rates levels of PD-L1, APE1, and P53 protein in hepatocellular carcinoma tissues are were 82.03%, 92.19%, and 60.94%. PD-L1 positive expression were significantly associated with clinical stage, The PD-L1 protein has a high expression in patients with I ~ II stage liver cancerHBV infection positive and nonportal vein thrombosis (p=0.041; p=0.030; p=0.014). It is inversely correlated with P53 and PD-L1 expression (correlation coefficient -0.227, p=0.010), and positively correlated with APE1 expression (correlation coefficient 0.189, p=0.032). The expression of PD-L1 is associated with the survival time of patients with hepatocellular carcinoma, and the median survival time of patients with high expression of PD-L1 is ten months. The median survival time of patients with low expression is five months (p=0.001). The relationship between the expression of APE1 and P53 protein and overall survival time of patients with hepatocellular carcinoma has not been found.

CONCLUSIONS

The PD-L1 and APE1 expression in hepatocellular carcinoma are related to the level of the expression of P53 protein. The expression state of PD-L1 may be a prognostic factor in hepatocellular carcinoma.

FoxO6 inhibits cell proliferation in lung carcinoma through up-regulation of USP7

Emerging evidence has suggested that misregulation of oncogenes and/or tumor suppressors has a crucial role in the development of lung carcinoma. The present study demonstrated that the expression levels of forkhead box O6 (FOXO6) were downregulated in lung cancer tissue samples, as compared with those in adjacent normal tissue. Overexpression of FOXO6 inhibited the proliferation of A549 human lung cancer cells, whereas knockdown of endogenous FOXO6 expression enhanced cell proliferation. Furthermore, ectopic FOXO6 expression induced the expression of ubiquitin-specific-processing protease 7 (USP7). As a result of this regulation, FOXO6 overexpression led to an elevation of p53 protein expression levels in A549 cells. In conclusion, the results of the present study indicated that the FOXO6/USP7 molecular network has an important role in the regulation of lung cancer development.

Berberine induces apoptosis in human multiple myeloma cell line U266 through hypomethylation of p53 promoter

Berberine has multiple pharmacological activities, such as anti-oxidative, anti-inflammation and anticancer activity. It reduces the proliferation and induces apoptosis in the multiple myeloma cell line, U266. Here we explored the detailed mechanism by analysing the gene expression profiles in U266 treated with or without berberine. DNMT1 andDNMT3B, encoding for a highly conserved member of the DNA methyltransferases, decreased significantly. By dissection of biochemical network database (BNDB) with Kyoto Encyclopaedia of Genes and Genomes (KEGG) annotation, the p53 signalling pathway related genes were altered. By using epigenetic chromatin modification enzymes PCR Array, gene expression microarray, RT-PCR and Bisulphite sequencing, the results show that berberine can repress the expression of DNMT1 and DNMT3B, which triggers hypomethylation of TP53 by changing the DNA methylation level and the alteration of p53 dependent signal pathway in human multiple melanoma cell U266.

TP53 loss creates therapeutic vulnerability in colorectal cancer

TP53, a well-known tumour suppressor gene that encodes p53, is frequently inactivated by mutation or deletion in most human tumours. A tremendous effort has been made to restore p53 activity in cancer therapies. However, no effective p53-based therapy has been successfully translated into clinical cancer treatment owing to the complexity of p53 signalling. Here we demonstrate that genomic deletion of TP53 frequently encompasses essential neighbouring genes, rendering cancer cells with hemizygous TP53 deletion vulnerable to further suppression of such genes. POLR2A is identified as such a gene that is almost always co-deleted with TP53 in human cancers. It encodes the largest and catalytic subunit of the RNA polymerase II complex, which is specifically inhibited by α-amanitin. Our analysis of The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia (CCLE) databases reveals that POLR2A expression levels are tightly correlated with its gene copy numbers in human colorectal cancer. Suppression of POLR2A with α-amanitin or small interfering RNAs selectively inhibits the proliferation, survival and tumorigenic potential of colorectal cancer cells with hemizygous TP53 loss in a p53-independent manner. Previous clinical applications of α-amanitin have been limited owing to its liver toxicity. However, we found that α-amanitin-based antibody-drug conjugates are highly effective therapeutic agents with reduced toxicity. Here we show that low doses of α-amanitin-conjugated anti-epithelial cell adhesion molecule (EpCAM) antibody lead to complete tumour regression in mouse models of human colorectal cancer with hemizygous deletion of POLR2A. We anticipate that inhibiting POLR2A will be a new therapeutic approach for human cancers containing such common genomic alterations.

Genetic dissimilarity between primary colorectal carcinomas and their lymph node metastases: ploidy, p53, bcl-2, and c-myc expression--a pilot study

The current paradigm of metastasis proposes that rare cells within primary tumors acquire metastatic capability via sequential mutations, suggesting that metastases are genetically dissimilar from their primary tumors. This study investigated the changes in the level of expression of a well-defined panel of cell proliferation, differentiation, and apoptosis markers between the primary colorectal cancer (CRC) and the corresponding synchronous lymph node (LN) metastasis from the same patients. DNA flow cytometry and immunostaining of p53, bcl-2, and c-myc were carried out on 36 cases of CRC radical resection specimens with their corresponding LN metastases. There was very low probability that the histological patterns of primary tumors and LN metastases are independent (p < 0.001). Metastatic tumors were significantly more diffusely positive for p53 than the primary tumors (p < 0.001). Conversely, primary tumors were significantly more diffusely positive for c-myc than metastatic tumors (p = 0.011). No significant difference was found between the LNs and the primary tumors in bcl-2 positivity (p = 0.538) and DNA aneuploidy (p = 0.35), with a tendency towards negative bcl-2 and less aneuploidy in LN metastases than primary tumors. In conclusion, LN metastatic colorectal carcinomas have a tendency of being less differentiated, with a higher incidence of diffuse p53 staining, lower incidence of bcl-2 staining, and less aneuploidy in comparison to their primary counterparts suggesting a more aggressive biological behavior, which could indicate the necessity for more aggressive adjuvant therapy.

[Influence of silver and titanium dioxide nanoparticles on the expression of genes of biomarkers of inflammatory responses and apoptosis]

In order to evaluate the toxic effect of silver (AgNP) and titanium dioxide (TiO2) nanoparticles their influence on the expression of genes of biomarkers of inflammatory responses and apoptosis in human lymphocytes was studied. An increase in the IL-6, IL-8, TNF-α and p53 genes expression in the concentration range of silver and titanium dioxide nanoparticles of 10-40 μk g/ml was found. Increased expression of IL-6, IL-8, TNF-α and p53 genes under the nanoparticles action indicates the stimulation of the immune system and of apoptosis, respectively.

[Comparative analysis of natural and synthetic antimutagens as regulators of gene expression in human cells under exposure to ionizing radiation]

This paper studies the effect of plant peptides of thionine Ns-W2 extracted from seeds of fennel flower (Nigella sativa) and β-purothionine from wheat germs (Triticum kiharae), as well as a synthetic antimutagen (crown-compound), on the expression of several genes involved in the.control of cellular homeostasis, processes of carcinogenesis, and radiation response in human rhabdomyosarcoma cells (RD cells), T-lymphoblastoid cell line Jurkat, and blood cells. All of these agents acted as antimutagens-anticarcinogens, reducing the expression of genes involved in carcinogenesis (genes of families MMP, TIMP, and IAP and G-protein genes) in a tumor cell. A pronounced reduction in the mRNA level of these genes was caused by thionine Ns-W2, and the least effect was demonstrated by β-purothionine. Antimutagens had very little effect on the mRNA levels of the several studied genes in normal blood cells.

Prostaglandin E2 inhibits p53 in human breast adipose stromal cells: a novel mechanism for the regulation of aromatase in obesity and breast cancer

Obesity is a risk factor for postmenopausal breast cancer and the majority of these cancers are estrogen dependent. Aromatase converts androgens into estrogens and its increased expression in breast adipose stromal cells (ASC) is a major driver of estrogen receptor-positive breast cancer. In particular, obesity-associated and tumor-derived factors, such as prostaglandin E2 (PGE2), have been shown to drive the expression of aromatase by stimulating the activity of the proximal promoter II (PII). The tumor-suppressor p53 is a key regulator of cell-cycle arrest and apoptosis and is frequently mutated in breast cancer. Mutations in p53 are rare in tumor-associated ASCs. Therefore, it was hypothesized that p53 is regulated by PGE2 and involved in the PGE2-mediated regulation of aromatase. Results demonstrate that PGE2 causes a significant decrease in p53 transcript and nuclear protein expression, as well as phosphorylation at Ser15 in primary human breast ASCs. Stabilization of p53 with RITA leads to a significant decrease in the PGE2-stimulated aromatase mRNA expression and activity, and PII activity. Interaction of p53 with PII was demonstrated and this interaction is decreased in the presence of PGE2. Moreover, mutation of the identified p53 response element leads to an increase in the basal activity of the promoter. Immunofluorescence on clinical samples demonstrates that p53 is decreased in tumor-associated ASCs compared with ASCs from normal breast tissue, and that there is a positive association between perinuclear (inactive) p53 and aromatase expression in these cells. Furthermore, aromatase expression is increased in breast ASCs from Li-Fraumeni patients (germline TP53 mutations) compared with non-Li-Fraumeni breast tissue. Overall, our results demonstrate that p53 is a negative regulator of aromatase in the breast and its inhibition by PGE2 provides a novel mechanism for aromatase regulation in obesity and breast cancer.

CDK2 transcriptional repression is an essential effector in p53-dependent cellular senescence-implications for therapeutic intervention

Cellular senescence, a form of cell-cycle arrest, is a tumor-suppressor mechanism triggered by multiple tumor-promoting insults, including oncogenic stress and DNA damage. The role of cyclin-dependent kinase 2 (CDK2) regulation has been evaluated in models of replicative senescence, but little is known regarding its role in other senescence settings. Using in vitro and in vivo models of DNA damage-and oncogene-induced cellular senescence, it was determined that activation of the tumor-suppressor protein p53 (TP53) resulted in repression of the CDK2 transcript that was dependent on intact RB. Ectopic CDK2 expression was sufficient to bypass p53-dependent senescence, and CDK2-specific inhibition, either pharmacologically (CVT313) or by use of a dominant-negative CDK2, was sufficient to induce early senescence. Pharmacologic inhibition of CDK2 in an in vivo model of pineal tumor decreased proliferation and promoted early senescence, and it also decreased tumor penetrance and prolonged time to tumor formation in animals lacking p53. In conclusion, for both oncogene- and DNA damage-induced cellular senescence, CDK2 transcript and protein are decreased in a p53- and RB-dependent manner, and this repression is necessary for cell-cycle exit during senescence.

IMPLICATIONS

These data show that CDK2 inhibition may be useful for cancer prevention in premalignant hyperproliferative lesions, as well as established tumors.

[New opportunities in the diagnosis of ulcerative colitis]

PURPOSE OF THE STUDY

to analyze the expression of markers of apoptosis and proliferation in patients with ulcerative colitis.

MATERIALS AND METHODS

in 80 patients with ulcerative colitis the analysis of expression of apoptosis marker BAX and proliferation marker Ki-67, as well as the cell cycle regulator p53 in biopsy materials of the mucous membrane of the colon was carried out.

THE RESULTS

decreased cell proliferative activity and increase of the apoptosis rate depending on the severity, the localization of the inflammatory process and its endoscopic activity were registered.

Genetic mutation of p53 and suppression of the miR-17∼92 cluster are synthetic lethal in non-small cell lung cancer due to upregulation of vitamin D Signaling

Lung cancer is the leading cause of cancer-related fatalities. Recent success developing genotypically targeted therapies, with potency only in well-defined subpopulations of tumors, suggests a path to improving patient survival. We used a library of oligonucleotide inhibitors of microRNAs, a class of posttranscriptional gene regulators, to identify novel synthetic lethal interactions between miRNA inhibition and molecular mechanisms in non-small cell lung cancer (NSCLC). Two inhibitors, those for miR-92a and miR-1226*, produced a toxicity distribution across a panel of 27 cell lines that correlated with loss of p53 protein expression. Notably, depletion of p53 was sufficient to confer sensitivity to otherwise resistant telomerase-immortalized bronchial epithelial cells. We found that both miR inhibitors cause sequence-specific downregulation of the miR-17∼92 polycistron, and this downregulation was toxic only in the context of p53 loss. Mechanistic studies indicated that the selective toxicity of miR-17∼92 polycistron inactivation was the consequence of derepression of vitamin D signaling via suppression of CYP24A1, a rate-limiting enzyme in the 1α,25-dihydroxyvitamin D3 metabolic pathway. Of note, high CYP24A1 expression significantly correlated with poor patient outcome in multiple lung cancer cohorts. Our results indicate that the screening approach used in this study can identify clinically relevant synthetic lethal interactions and that vitamin D receptor agonists may show enhanced efficacy in p53-negative lung cancer patients.

Prognostic value of LAMP3 and TP53 overexpression in benign and malignant gastrointestinal tissues

Lysosomal associated membrane protein 3 (LAMP3) is a newly identified tumor-specific protein. It is a downstream target gene of tumor suppressor TP53 and its expression has been associated with hypoxia-induced metastasis and poor overall survival in cervical and breast cancers. However, little is known of LAMP3 protein expression in gastrointestinal cancer and its prognostic value. We determined protein expression of LAMP3 and TP53 in both gastric (n=750) and colorectal (n=479) tissues by immunohistochemistry analysis on tissue microarray (TMA), their expression was correlated with patients' clinical parameters. LAMP3 and TP53 protein expression was significantly higher in cancerous tissues compared to normal and benign tissues. In both gastric and colorectal cancers, high LAMP3 protein expression (LAMP3+) was significantly associated with tumor stage (P=0.014 and P<0.001). No correlation between LAMP3 and TP53 expression was observed. Patients with high LAMP3 expression but not high TP53 expression had a poor overall survival (for gastric cancer P<0.001, CI: 1.762-4.567; for colorectal cancer P=0.036, CI: 1.062-5.980). Our data suggest that epithelial LAMP3 expression is an independent prognostic marker for gastrointestinal cancer.

Porcine parvovirus infection induces apoptosis in PK-15 cells through activation of p53 and mitochondria-mediated pathway

Porcine parvovirus (PPV) infection has been reported to induce the cytopathic effects (CPE) in some special host cells and contribute the occurrence of porcine parvovirus disease, but the molecular mechanisms underlying PPV-induced CPE are not clear. In this study, we investigated the morphological and molecular changes of porcine kidney cell line (PK-15 cells) infected with PPV. The results showed that PPV infection inhibited the viability of PK-15 cells in a time and concentration dependent manner. PPV infection induced typical apoptotic features including chromatin condensation, apoptotic body formation, nuclear fragmentation, and Annexin V-binding activity. Further studies showed that Bax was increased and translocated to mitochondria, whereas Bcl-2 was decreased in PPV-infected cells, which caused mitochondrial outer-membrane permeabilization, resulting in the release of mitochondrial cytochrome c, followed by caspase-9 and caspase-3 activation. However, the expression of Fas and Fas ligand (FasL) did not appear significant changes in the process of PPV-induced apoptosis. Moreover, PPV infection activated p53 signaling, which was involved in the activation of apoptotic signaling induced by PPV infection via regulation of Bax and Bcl-2. Taken together, our results demonstrated that PPV infection induced apoptosis in PK-15 cells through activation of p53 and mitochondria-mediated apoptosis pathway. This study may contribute to shed light on the molecular pathogenesis of PPV infection.

Functional interaction between cyclooxygenase-2 and p53 in response to an endogenous electrophile

Cyclooxygenase-2 (Cox-2) is rapidly expressed by various stimuli and plays a key role in conversion of free arachidonic acid to prostaglandins. We have previously identified 4-hydroxy-2-nonenal (HNE), a lipid peroxidation-derived electrophile, as the potent Cox-2 inducer in rat epithelial RL34 cells and revealed that the HNE-induced Cox-2 expression resulted from the stabilization of Cox-2 mRNA that is mediated by the p38 mitogen-activated protein kinase signaling pathway. In the present study, we investigated an alternative regulatory mechanism of Cox-2 expression mediated by a transcription factor p53. In addition, to characterize the causal role for Cox-2, we examined the effects of Cox-2 overexpression in RL34 cells. To examine whether the HNE-induced Cox-2 expression was mechanistically linked to the p53 expression, we analyzed changes in Cox-2 and p53 expression levels in response to HNE and observed that the Cox-2 levels were inversely correlated with the p53 levels. Down-regulation of p53 followed by the activation of a transcription factor Sp1 was suggested to be involved in the HNE-induced Cox-2 gene expression. To characterize the effect of Cox-2 expression in the cells, we established the Cox-2-overexpressing derivatives of RL34 cells by stable transfection with Cox-2 cDNA. An oligonucleotide microarray analysis revealed a dramatic down-regulation of the proteasome subunit RC1 in the Cox-2 overexpressed cells compared to the empty-vector transfected control cells. Consistent with the Cox-2-mediated down-regulation of proteasome, a moderate reduction of the proteasome activities was observed. This proteasome dysfunction mediated by the Cox-2 overproduction was associated with the enhanced accumulation of p53 and ubiquitinated proteins, leading to the enhanced sensitivity toward electrophiles. These results suggest the existence of a causal link between Cox-2 and p53, which may represent a toxic mechanism of electrophilic lipid peroxidation products.

p53 up-regulation during colorectal carcinogenesis

BACKGROUND

We previously found foci of p53 up-regulation in dysplasia in colorectal adenomas (CRAs). The present study aimed at exploring the frequency of this phenomenon in CRAs with and without submucosal invasive carcinoma.

MATERIALS AND METHODS

Sections from 568 polypectomies or surgical resections harbouring a CRA (without or with submucosal invasion) or overt colorectal carcinomas were challenged with p53 immunostaining. The largest section from single colorectal neoplasias was measured by the aid of a calibrated ocular scale in a conventional microscope. Lesions were divided into small adenomas (≤10 mm in size), large adenomas (≥11 mm in size), adenomas with submucosal invasion, and overt invasive carcinomas (without any recognizable adenoma remnant tissue).

RESULTS

CRAs with three or more dysplastic foci of p53-up-regulation gradually increased from 8% in small adenomas (size: ≤10 mm) to 48% in large adenomas (size: ≥11 mm), and to 65% in the adenomatous tissue in adenomas displaying submucosal invasion), but plummeted to 13% in the submucosal carcinomatous tissue and to 11% in overt carcinomas. In contrast, extensive p53 up-regulation predominated in the submucosal carcinomatous tissue (87%) and in overt carcinomas (89%).

CONCLUSION

The frequency of foci of dysplastic glands with up-regulation of p53 (hotspots) gradually increased from small to larger CRAs, being highest in the adenomatous tissue of CRAs with submucosal invasive carcinoma. The foci of p53 up-regulation became confluent (appreciated as extensive up-regulation) in the submucosal carcinomatous tissue and in overt carcinomas. It is concluded that a high number of foci with p53 up-regulation in adenomatous tissue might be required before submucosal invasive carcinoma ensues.

Clinical implications of MTA proteins in human cancer

Metastasis-associated gene or metastasis tumor antigen 1 (MTA1) is a new member of cancer progression-related gene family. It was first identified in rat mammary adenocarcinoma and later recognized as an important constituent of nucleosomal remodeling complex (NuRD), displaying dual regulatory functions as a co-repressor and co-activator for a large number of genes. Chromatin remodelers are ATP-dependent multi-protein chromatin modifying machines. These complexes alter the nucleosome positioning regulating the accessibility of genomic DNA to various transcription factors and thus modulate eukaryotic gene transcription. Since its identification two decades ago, MTA1 has been reported to be overexpressed in many cancers. Moreover, its overexpression has also been correlated with transformation and tumor progression. Furthermore, MTA1 has been shown to modulate the response of several tumor suppressor genes like p53 and oncogenes like c-myc. Taken together, current literature suggests that MTA proteins, especially MTA1, act as a master co-regulatory molecule involved in the carcinogenesis and progression of various malignant tumors. The primary focus of this review is to provide an overview of the MTA proteins with special emphasis on its role in cancer and use as a marker for cancer progression and potential target for therapy.

Tanshinone IIA inhibits gastric carcinoma AGS cells through increasing p-p38, p-JNK and p53 but reducing p-ERK, CDC2 and cyclin B1 expression

Tanshinone IIA (Tan-IIA) is extracted from Danshen (Salviae miltiorrhizae radix). It possesses antitumor activity against a variety of human cancer cells and its induction of apoptosis and inhibition of proliferation of gastric cancer cells are well-documented. However, the molecular mechanisms by which Tan-IIA inhibits gastric cancer have not been well-elucidated. In the present study, we evaluated the cytotoxicity of Tan-IIA against human gastric cancer AGS cells by the (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) MTT assay. The protein expression of tumor necrosis factor-alpha (TNF-α), FAS, p53, p21, cyclin A, cyclin B1, extracellular-related kinase (ERK), phospho extracellular-related kinase (p-ERK), p38, p-p38, Jun-amino-terminal kinase (JNK), phospho Jun-amino-terminal kinase (p-JNK) and β-actin in AGS cells were measured by western blotting. The cell-cycle distribution was analyzed by flow cytometry. The results showed that Tan-IIA inhibited AGS cells with time- and dose-dependent manners. AGS cells treated with Tan-IIA up-regulated the protein expression of TNFα, FAS, p-p38, p-JNK, p53, p21, caspase-3 and caspase-8 but reduced that of p-ERK, CDC2, cyclin A, and cyclin B1. The results also showed that Tan-IIA dose dependently induced G2/M phase arrest. These findings demonstrate that Tan-IIA can inhibit AGS human gastric cancer cells; one of the molecular mechanisms may be through increasing the protein expression of p-p38 and p-JNK, but decreasing that of p-ERK to induce the activation of p53, followed by increasing the protein expression of p21 to down-regulate CDC2 and cyclin B1 expression which then induces G2/M phase arrest. Another route may be through increasing the protein expression of TNF-α, FAS, caspase-8 and caspase-3 to induce apoptosis.

[Prognostic and predictive value of koilocytosis, expression of e6 hpv types 16/18, p16ink4a, p53 in locally advanced squamous cell carcinomas of oral cavity and oropharynx, associated with human papillomavirus]

To determine the predictive and prognostic value of koilocytosis, expression of E6 HPV types 16/18, p16INK4a, p53 in patients with locally advanced HPV-associated squamous cell carcinoma of oral cavity and oropharynx. In biopsy specimens of squamous cell carcinomas of oral cavity and oropharynx from 60 patients performed koylocytes count, immunohistochemical detection of HPV 16/18 types E6 protein, proteins p16INK4a and p53. Koilocytosis was detected in 50 patients (83.3%); in all 60 patients (100%) were simultaneous expression of p16INK4a and E6 HPV types 16/18; p53 expression was found in 37 patients (61.7%). After combined treatment (induction chemotherapy followed by radiotherapy) stable disease (SD) was detected in 11 patients (18.3%), partial response (PR) - in 25 patients (41.7%), complete response (CR) - in 24 patients (40.0%). There were no cases of disease progression. Treatment effect correlated with expression of p16INK4a (ρ = 0.3, p = 0.024) and expression of p53 (ρ = - 0.3, p = 0.019). Patients with a low expression of p16INK4a (2 points) and high expression of p53 (4 "+") had a high level of SD and had no CR. For all patients, the median of overall survival (OS) was 17 months, 1-year cumulative survival rate was 66.7%, 2-year cumulative survival rate - 35.0%. Median of overall survival was correlated with koilocytosis (ρ=0.5, p<0,001) and expression of E6 HPV types 16/18 (ρ=0.9, p<0.001), p16INK4a (ρ=0.9, p=0.037), p53 (ρ=-0.9; p<0.001). Patients with low expression of p53 (0 and 1 "+") had cumulative 1-year survival rates 87% and 90%, respectively (p<0.001), 2-year survival rates - 52% and 80%, respectively (p=0.015). In the Cox proportional hazards model the significant prognostic factors were prevalence of primary tumor (OR 2.2, 95% CI 1.3 - 3.5, p=0.003) and p53 expression (OR 1.3, 95% CI 1.1=1.7, p=0.016). High expression of p16INK4a associated with a high effect of combined treatment, high expression of a p53 - with low effect of treatment. Koilocytosis and expression of E6 HPV 16/18 types have no predictive value. Median of overall survival correlated with koilocytosis, expression of E6 HPV types 16/18 and p16INK4a. P53 expression is an independent predictor of negative prognosis for overall survival. Increase in the level of p53 expression is associated with a reduction in overall survival and cumulative 1- and 2-year survival rate. For patients with low expression of p16INK4a or high p53 expression, surgery is advisable to consider as first stage of treatment.

Prognostic role of bcl-xL and p53 in childhood acute lymphoblastic leukemia

Molecular parameters involved in the prediction of response of childhood acute lymphoblastic leukemia (ALL) are still unclear. We have evaluated the expression and mutational status of p53 and the expression of bcl-x(L) and bax in a series of 62 consecutive children (median age: 4 years; 38 males and 24 females) affected by de novo ALL. Alterations and overexpression of p53 were uncommon events (9/62, 14.5%) while bcl-x(L) and bax overexpression were frequent (about 70%). EFS was directly correlated to age<6 years (p=0.0178), nonT phenotype (p=0.0470), WBC at diagnosis<or=20000/microl (p=0.0093), response to induction therapy with prednisone (p=0.0211) and inversely correlated to mutated p53 or overexpression of p53 (p=0.0039) and high intensity of Bcl-xL expression (p=0.0055). OS was directly correlated with age<6 years (p=0.0004), female gender (p=0.0139), nonT phenotype (p=0.0012), WBC at diagnosis<or=20000/microl (p=0.0187), response to induction therapy with prednisone (p=0.0211), wild type p53 or low expression of p53 (p=0.035). When all factors were considered in a stepwise Cox regression analysis, only the good response to PDN (p=0.013) and the low intensity of Bcl-xL expression (p=0.001) were independent significant prognostic factors with regard to EFS. Moreover, only age (p=0.022), gender (p=0.036) and WBC at the diagnosis (p=0.050) were independent prognostic factors with regard to OS. Moreover, the mutated status of p53 was statistically correlated to the resistance to the induction therapy with PDN (correlation coefficient: -0.349, p=0.008). In conclusion, both bcl-xL and bax were frequently expressed at high intensity, but only bcl-xL was an independent predictor of EFS in our series. Moreover, p53 alterations were uncommon and alone not strong independent predictors of outcome, but they were correlated to poor response to therapy with PDN and inversely correlated to EFS and OS in univariate analysis.

Reversal of p53 epigenetic silencing in multiple myeloma permits apoptosis by a p53 activator

Inactivation of the p53 pathway is a common feature of neoplasia. Dysregulation of the p53 pathway has been shown to involve mutations of p53, increased expression of the p53 inhibitor HDM-2, or epigenetic silencing of the p53 promoter. In multiple myeloma, a neoplasia of terminally differentiated B cells, p53 mutations and deletions are relatively rare and occur in late stage disease. Here, we show that the p53 promoter is hypermethylated in several multiple myeloma cell lines in comparison to normal plasma cells. Two cell lines containing mutant p53, Lp-1 and OPM-2, show a methylation pattern that suggests that they contain one methylated and one unmethylated mutant allele. Two other cell lines, KMS-11 and OPM-2, show hypermethylation of p53 with a lack of expression. In all cell lines tested, treatment with a demethylating agents results in higher expression of p53. Furthermore, following increased expression of p53, treatment of the myeloma cell lines with a p53 activating peptide induces apoptosis. Therefore, combinatorial treatment with demethylating agents followed by delivery of a p53 activating peptide may be an effective therapeutic strategy against multiple myeloma.

Reliable generation of induced pluripotent stem cells from human lymphoblastoid cell lines

Patient-specific induced pluripotent stem cells (iPSCs) hold great promise for many applications, including disease modeling to elucidate mechanisms involved in disease pathogenesis, drug screening, and ultimately regenerative medicine therapies. A frequently used starting source of cells for reprogramming has been dermal fibroblasts isolated from skin biopsies. However, numerous repositories containing lymphoblastoid cell lines (LCLs) generated from a wide array of patients also exist in abundance. To date, this rich bioresource has been severely underused for iPSC generation. We first attempted to create iPSCs from LCLs using two existing methods but were unsuccessful. Here we report a new and more reliable method for LCL reprogramming using episomal plasmids expressing pluripotency factors and p53 shRNA in combination with small molecules. The LCL-derived iPSCs (LCL-iPSCs) exhibited identical characteristics to fibroblast-derived iPSCs (fib-iPSCs), wherein they retained their genotype, exhibited a normal pluripotency profile, and readily differentiated into all three germ-layer cell types. As expected, they also maintained rearrangement of the heavy chain immunoglobulin locus. Importantly, we also show efficient iPSC generation from LCLs of patients with spinal muscular atrophy and inflammatory bowel disease. These LCL-iPSCs retained the disease mutation and could differentiate into neurons, spinal motor neurons, and intestinal organoids, all of which were virtually indistinguishable from differentiated cells derived from fib-iPSCs. This method for reliably deriving iPSCs from patient LCLs paves the way for using invaluable worldwide LCL repositories to generate new human iPSC lines, thus providing an enormous bioresource for disease modeling, drug discovery, and regenerative medicine applications.