RNA N6-methyladenosine modulates endothelial atherogenic responses to disturbed flow in mice

Atherosclerosis preferentially occurs in atheroprone vasculature where human umbilical vein endothelial cells are exposed to disturbed flow. Disturbed flow is associated with vascular inflammation and focal distribution. Recent studies have revealed the involvement of epigenetic regulation in atherosclerosis progression. N6-methyladenosine (m6A) is the most prevalent internal modification of eukaryotic mRNA, but its function in endothelial atherogenic progression remains unclear. Here, we show that m6A mediates the epidermal growth factor receptor (EGFR) signaling pathway during EC activation to regulate the atherosclerotic process. Oscillatory stress (OS) reduced the expression of methyltransferase like 3 (METTL3), the primary m6A methyltransferase. Through m6A sequencing and functional studies, we determined that m6A mediates the mRNA decay of the vascular pathophysiology gene EGFR which leads to EC dysfunction. m6A modification of the EGFR 3' untranslated regions (3'UTR) accelerated its mRNA degradation. Double mutation of the EGFR 3'UTR abolished METTL3-induced luciferase activity. Adenovirus-mediated METTL3 overexpression significantly reduced EGFR activation and endothelial dysfunction in the presence of OS. Furthermore, thrombospondin-1 (TSP-1), an EGFR ligand, was specifically expressed in atheroprone regions without being affected by METTL3. Inhibition of the TSP-1/EGFR axis by using shRNA and AG1478 significantly ameliorated atherogenesis. Overall, our study revealed that METTL3 alleviates endothelial atherogenic progression through m6A-dependent stabilization of EGFR mRNA, highlighting the important role of RNA transcriptomics in atherosclerosis regulation.

Prognositic significance of P-cadherin expression in breast cancer: Protocol for a meta-analysis

BACKGROUND

P-cadherin is a calcium-dependent cell-cell adhesion glycoprotein. It has been implicated in invasiveness and metastasis. However, the clinical prognostic value of overexpression of P-cadherin in patients with breast cancer (BC) remains unsettled.

METHODS

A systematic literature search will be performed in all available databases to quantitatively review eligible studies and identify all relevant data, which could be used to detect the relationship between overexpression of P-cadherin and overall survival (OS), disease-free survival (DFS), and clinicopathological parameters. Hazard ratio and 95% confidence intervals (CIs) or P value will be employed as effect measures to estimate the correlation between P-cadherin and the oncologic outcomes including overall survival (OS), disease-free survival (DFS). Odds ratios (ORs) and the 95% CIs will be evaluated for the pooled analysis of the correlation between P-cadherin expression and clinicopathological features. We will use the Review Manager (Revman) 5.3.5 software (Cochrane Community, London, United Kingdom) and STATA 14 software (version 14.0; Stata Corp, College Station, TX) to perform the meta-analysis to calculate the data.

RESULTS

The review will provide a high-quality synthesis of current evidence of the prognostic role of P-cadherin in BCs. The results will be published in a peer-reviewed journal.

CONCLUSION

We hope that the results of this study will provide significant evidence to assess whether the expression of P-cadherin is associated with poor prognosis in patients with BC.

PROSPERO REGISTRATION NUMBER

This meta-analysis protocol has been registered in the PROSPERO network with registration number: CRD42019119880.

[Effect and mechanism of EGFR expression in macrophages on the anti-cancer effect of berberine on colorectal cancer]

OBJECTIVE

To investigate the effect and explore its possible mechanisms of epidermal growth factor receptor(EGFR) expression in macrophages on the anti-cancer effect of berberine (BER) on the growth of colorectal cancer.

METHODS

Mice with EGFR gene defects in macrophages (Egfr(fl/fl) LysM-Cre) and with EGFR gene expression in macrophages (LysM-Cre) (control group) were treated with azoxymethane (AOM) to establish colorectal tumor models. These models were treated with or without berberine (BER) intervention. The number of colorectal tumors and the gut length in the two groups were measured. The proliferation of tumor cells was detected by Ki-67 immunohistochemistry and apoptosis was detected by annexin V-FITC fluorescence labeling. Western blot was used to detect the expression of cleaved-caspase-3 protein.

RESULTS

After treated with AOM, the colorectal tumor number was 10.26 ± 1.43 in the LysM-Cre group and 7.62 ± 1.05 in the Egfr(fl/fl) LysM-Cre group, showing a significant difference (P = 0.021). The gut length was (6.04 ± 1.06) cm in the LysM-Cre group and (6.39 ± 0.92) cm in the gfrfl/flLysM-Cre group, with a non-significant difference between the two groups (P = 0.075). After treated with AOM plus BER intervention, the colorectal tumor number of the LysM-Cre group was 8.35 ± 1.22 and that in the Egfr(fl/fl) LysM-Cre group was 2.66 ± 0.38, showing a very significant difference between the two groups (P = 0.006). The gut length of the LysM-Cre group was (7.34 ± 1.16) cm and that of the Egfr(fl/fl) LysM-Cre group was (10.01 ± 1.72) cm (P = 0.028). After treated with AOM, the ratio of Ki-67-positive tumor cells in the LysM-Cre group was (78.31 ± 3.43)% and that in the Egfr(fl/fl) LysM-Cre group was (75.85 ± 2.92)% (P = 0.282). After AOM plus BER treatment, the ratio of Ki-67-positive tumor cells in the LysM-Cre group was (42.43 ± 3.09)% and that in the Egfr(fl/fl) LysM-Cre group was significantly lower (29.65 ± 2.47)% (P = 0.018). The ratio of annexin V-positive tumor cells was (0.95 ± 0.13)% in the LysM-Cre group, not significantly different from (1.13 ± 0.16)% in the Egfr(fl/fl) LysM-Cre group (P = 0.175). After AOM plus BER treatment, the ratio of annexin V-positive tumor cells in the LysM-Cre group was (32.10 ± 1.97)%, significantly lower than the (47.08 ± 2.83)% in the Egfr(fl/fl) LysM-Cre group (P = 0.010). The level of cleaved-caspase-3 protein expression was 235.92 ± 19.73 in the Egfr(fl/fl) LysM-Cre group, significantly higher than the 119.71 ± 12.87 in the LysM-Cre group (P = 0.012).

CONCLUSIONS

The growth of colorectal cancer cells in mice can be inhibited by BER treatment, and this anti-cancer effect of BER can be further enhanced by EGFR gene knockout in macrophages. The mechanisms may be related to the inhibition of proliferation and promotion of apoptosis in colorectal cancer cells.

Adamantinomatous craniopharyngioma: pathology, molecular genetics and mouse models

Adamantinomatous craniopharyngiomas (ACPs) are histologically benign but clinically aggressive epithelial tumours of the sellar region that are associated with high morbidity and occasional mortality. Research from the last 3 years has provided important insights into the molecular and cellular pathogenesis of these tumours. It has become established that mutations in CTNNB1 (encoding β-catenin), leading to the over-activation of the WNT pathway, underlie the molecular aetiology of human ACP. Interestingly, the effect of these mutations is restricted to a small number of tumour cells, mostly forming clusters, which recent research has shown to be critical for tumorigenesis in mice and humans. Several pathways have been found to be activated in these clusters including the epidermal growth factor receptor and the sonic hedgehog pathways, offering potential therapeutic targets. A novel and unexpected role for pituitary stem cells has been proposed, which is fundamentally distinct from the cancer stem cell paradigm. The study of these benign tumours could reveal important insights into general mechanisms underlying the initial steps of tumorigenesis and facilitate novel tools to improve managements of the patients.

Epigallocatechin 3-O-gallate induces 67 kDa laminin receptor-mediated cell death accompanied by downregulation of ErbB proteins and altered lipid raft clustering in mammary and epidermoid carcinoma cells

Since the administration of synthetic medicines is associated with drug resistance and undesired side effects, utilization of natural compounds could be an alternative and complementary modality to inhibit or prevent the development of tumors. Epigallocatechin 3-O-gallate (EGCG, 1), the major flavan component of green tea, and genistein (2), a soy isoflavonoid, are known to have chemopreventive and chemotherapeutic effects against cancer. This study demonstrated that both flavonoids inhibit cell proliferation, an effect enhanced under serum-free conditions. Compound 1, but not 2, induced downregulation of ErbB1 and ErbB2 in mammary and epidermoid carcinoma cells, and its inhibitory effect on cell viability was mediated by the 67 kDa laminin receptor (67LR). While 1 was superior in inducing cell death, 2 was more efficient in arresting the tumor cells in the G2/M phase. Furthermore, number and brightness analysis revealed that 1 decreased the homoclustering of a lipid raft marker, glycosylphosphatidylinositol-anchored GFP, and it also reduced the co-localization between lipid rafts and 67LR. The main conclusion made is that the primary target of 1 may be the lipid raft component of the plasma membrane followed by secondary changes in the expression of ErbB proteins. Compound 2, on the other hand, must have other unidentified targets.

Progesterone promotes focal adhesion formation and migration in breast cancer cells through induction of protease-activated receptor-1

Progesterone and progestins have been demonstrated to enhance breast cancer cell migration, although the mechanisms are still not fully understood. The protease-activated receptors (PARs) are a family of membrane receptors that are activated by serine proteases in the blood coagulation cascade. PAR1 (F2R) has been reported to be involved in cancer cell migration and overexpressed in breast cancer. We herein demonstrate that PAR1 mRNA and protein are upregulated by progesterone treatment of the breast cancer cell lines ZR-75 and T47D. This regulation is dependent on the progesterone receptor (PR) but does not require PR phosphorylation at serine 294 or the PR proline-rich region mPRO. The increase in PAR1 mRNA was transient, being present at 3  h and returning to basal levels at 18  h. The addition of a PAR1-activating peptide (aPAR1) to cells treated with progesterone resulted in an increase in focal adhesion (FA) formation as measured by the cellular levels of phosphorylated FA kinase. The combined but not individual treatment of progesterone and aPAR1 also markedly increased stress fiber formation and the migratory capacity of breast cancer cells. In agreement with in vitro findings, data mining from the Oncomine platform revealed that PAR1 expression was significantly upregulated in PR-positive breast tumors. Our observation that PAR1 expression and signal transduction are modulated by progesterone provides new insight into how the progestin component in hormone therapies increases the risk of breast cancer in postmenopausal women.

Molecular characteristics predict clinical outcomes: prospective trial correlating response to the EGFR tyrosine kinase inhibitor gefitinib with the presence of sensitizing mutations in the tyrosine binding domain of the EGFR gene

PURPOSE

To determine if tumor regression following treatment with gefitinib correlates with the presence of sensitizing mutations in epidermal growth factor receptor (EGFR).

PATIENTS AND METHODS

Patients with resectable stage I and II non-small cell lung cancer (NSCLC) enriched for the likelihood of EGFR mutation (≤ 15 pack-year cigarette smoking history and/or a component of bronchioloalveolar carcinoma) received preoperative gefitinib for 21 days. Tumor specimens were analyzed for EGFR and KRAS mutations and EGFR protein expression and amplification. Patients with 25% or more reduction in tumor size measured bidimensionally at 3 weeks and/or patients with an EGFR mutation received adjuvant gefitinib for 2 years postoperatively.

RESULTS

Fifty patients with stage I/II NSCLC were treated. After 21 days of preoperative gefitinib a response of 25% or more was observed in 21 of 50 (42%) patients. Seventeen of 21 patients with a response had an EGFR mutation and 4 of 21 patients with a response did not (P = 0.0001). Twenty-five of 50 patients were eligible to receive adjuvant gefitinib. With a median follow-up of 44.1 months, 2-year disease free survival for EGFR mutant patients and for those who received adjuvant gefitinib was not statistically different than those who were EGFR wild-type and those who did not receive adjuvant gefitinib. The median disease free and overall survivals have not been reached.

CONCLUSIONS

The presence of sensitizing EGFR mutations correlates with radiographic response. A short course of preoperative treatment serves a platform for evaluating activity of new agents and assures sufficient tumor availability for correlative analyses.

Role of the C-terminal linear region of EGF-like growth factors in ErbB specificity

The epidermal growth factor (EGF)-like growth factors bind their ErbB receptors in a highly selective manner. Recently, we have shown that the sequence YYDLL in the C-terminal linear region is compatible with binding to all ligand-binding ErbB receptors. In the present study, we show that introduction of the YYDLL sequence into the ErbB1 specific ligands EGF and transforming growth factor-alpha (TGFalpha) broadened their receptor specificity towards ErbB4. Upon introduction of the YYDLL sequence into epiregulin, which by itself binds ErbB1 and ErbB4 but not ErbB3, its binding specificity was broadened to ErbB3, concomitant with enhanced affinity for ErbB4. Introduction of the YYDLL sequence into NRG1beta resulted in a 10-fold increase in affinity for ErbB3, without affecting its receptor specificity. Remarkably, the strongly enhanced affinity for ErbB3 negatively influenced their mitogenic activity towards cells coexpressing ErbB2 and ErbB3. These observations are discussed in terms of the optimised ErbB affinity, selectivity and mitogenic potential that have taken place during evolution.

Mutation of ERBB2 provides a novel alternative mechanism for the ubiquitous activation of RAS-MAPK in ovarian serous low malignant potential tumors

Approximately, 10% to 15% of serous ovarian tumors fall into the category designated as tumors of low malignant potential (LMP). Like their invasive counterparts, LMP tumors may be associated with extraovarian disease, for example, in the peritoneal cavity and regional lymph nodes. However, unlike typical invasive carcinomas, patients generally have a favorable prognosis. The mutational profile also differs markedly from that seen in most serous carcinomas. Typically, LMP tumors are associated with KRAS and BRAF mutations. Interrogation of expression profiles in serous LMP tumors suggested overall redundancy of RAS-MAPK pathway mutations and a distinct mechanism of oncogenesis compared with high-grade ovarian carcinomas. Our findings indicate that activating mutation of the RAS-MAPK pathway in serous LMP may be present in >70% of cases compared with approximately 12.5% in serous ovarian carcinomas. In addition to mutations of KRAS (18%) and BRAF (48%) mutations, ERBB2 mutations (6%), but not EGFR, are prevalent among serous LMP tumors. Based on the expression profile signature observed throughout our serous LMP cohort, we propose that RAS-MAPK pathway activation is a requirement of serous LMP tumor development and that other activators of this pathway are yet to be defined. Importantly, as few nonsurgical options exist for treatment of recurrent LMP tumors, therapeutic targeting of this pathway may prove beneficial, especially in younger patients where maintaining fertility is important.

EGFR gene and protein expression in breast cancers

AIMS

To measure the EGFR gene amplification and protein expression, and to compare the EGFR expression with HER2 expression similarly measured.

METHODS

EGFR gene amplification was assayed by fluorescence in situ hybridization and its protein expression was evaluated by immunohistochemistry on tissue microarray of 165 consecutive invasive breast cancers.

RESULTS

EGFR protein overexpression was observed in 20.6% of the 165 studied cases, but gene amplification was observed in 7.9% only. EGFR protein was expressed in 33.3% of HER2-amplified tumors, and in only 16.3% of HER2 non-amplified tumors. EGFR expression significantly increased in HER2 gene-amplified and protein-expressing tumors as well. On survival analysis, EGFR expression was a significant prognostic factor for the disease-free and overall survival of the patients.

CONCLUSIONS

EGFR protein expression was independent of EGFR gene amplification status, whereas it was intimately associated with HER2 amplification and overexpression in breast cancer.

Epidermal growth factor signaling mediated by grb2 associated binder1 is required for the spatiotemporally regulated proliferation of olig2-expressing progenitors in the embryonic spinal cord

Gab1 (Grb2 associated binder1) has been identified as an adaptor molecule downstream of many growth factors, including epidermal growth factor (EGF), fibroblast growth factor, and platelet-derived growth factor, which have been shown to play crucial roles as mitotic signals for a variety of neural progenitor cells, including stem cells, both in vitro and in vivo. Here, we show that Gab1 deficiency results in a reduction in the number of Olig2-positive (Olig2(+)) progenitor cells in the developing mouse spinal cord after embryonic day 12.5 (E12.5), when gliogenesis starts in the pMN domain where the EGF receptor (EGFR) is expressed predominantly. Our in vitro analysis further revealed that Gab1 is essential for EGF-dependent proliferation of Olig2(+) progenitor cells derived from the E12.5 ventral and E14.5 dorsal but not ventral spinal cord, whereas Gab1 is always required for the activation of Akt1 but not of ERK1/2. Moreover, we found that the action of the Gab1/Akt pathway is context-dependent, since constitutively active Akt1 could rescue the proliferation defect only in the E12.5 spinal cord of the Gab1-deficient mouse in vitro. Finally, we demonstrated that EGFR-deficient mice and Gab1-deficient mice showed a similar reduction in the number of Olig2(+) progenitor cells in the developing spinal cord. These findings indicate that EGFR-mediated signaling through Gab1/Akt contributes to the sufficient expansion of Olig2(+) progenitor cells in a spatiotemporally regulated manner, which represents the origin of glial cells in the developing spinal cord. Disclosure of potential conflicts of interest is found at the end of this article.

Matrix metalloproteinase-7-catalyzed release of HB-EGF mediates deoxycholyltaurine-induced proliferation of a human colon cancer cell line

Prior evidence indicates that bile acids stimulate colon cancer cell proliferation by muscarinic receptor-induced transactivation of epidermal growth factor receptors (EGFR). To explore further the mechanism underlying this action, we tested the hypothesis that bile acids activate a matrix metalloproteinase (MMP) that catalyzes release of an EGFR ligand. Initial studies showed that non-selective MMP inhibitors blocked the actions of deoxycholyltaurine (DCT), thereby indicating a role for MMP-catalyzed release of an EGFR ligand. DCT-induced cell proliferation was reduced by increasing concentrations of EGFR kinase inhibitors, by antibodies to the ligand binding domain of EGFR, by neutralizing antibodies to heparin binding-EGF-like growth factor (HB-EGF) and by CRM197, an inhibitor of HB-EGF release. These findings and our observations with more selective MMP inhibitors suggested that MMP-7, an enzyme known to release HB-EGF, plays a key role in mediating bile acid-induced H508 colon cancer cell proliferation. We observed that recombinant HB-EGF and MMP-7 mimicked both the signaling and proliferative actions of bile acids. Strikingly, reducing MMP-7 expression with either neutralizing antibody or small interfering RNA attenuated the actions of DCT. MMP-7 expression in H508 cells was confirmed using quantitative reverse transcription PCR. DCT stimulated a greater than 10-fold increase in MMP-7 gene transcription. Co-localization of pro-MMP-7 and pro-HB-EGF at the cell surface (immunofluorescence microscopy) was demonstrated, indicating proximity of the enzyme to its substrate. These findings provide strong evidence that in H508 human colon cancer cells, DCT-induced transactivation of EGFR is mediated by MMP-7-catalyzed release of the EGFR ligand HB-EGF.

Genetic Classification of Lung Adenocarcinoma Based on Array-Based Comparative Genomic Hybridization Analysis: Its Association with Clinicopathologic Features

The array-based comparative genomic hybridization using microarrayed bacterial artificial chromosome clones allows high-resolution analysis of genome-wide copy number changes in tumors. To analyze the genetic alterations of primary lung adenocarcinoma in a high-throughput way, we used laser-capture microdissection of cancer cells and array comparative genomic hybridization focusing on 800 chromosomal loci containing cancer-related genes. We identified a large number of chromosomal numerical alterations, including frequent amplifications on 7p12, 11q13, 12q14-15, and 17q21, and two homozygous deletions on 9p21 and one on 8p23. Unsupervised hierarchical clustering analysis of multiple alterations revealed three subgroups of lung adenocarcinoma that were characterized by the accumulation of distinct genetic alterations and associated with smoking history and gender. The mutation status of the epidermal growth factor receptor (EGFR) gene was significantly associated with specific genetic alterations and supervised clustering analysis based on EGFR gene mutations elucidated a subgroup including all EGFR gene mutated tumors, which showed significantly shorter disease-free survival. Our results suggest that there exist multiple molecular carcinogenesis pathways in lung adenocarcinoma that may associate with smoking habits and gender, and that genetic cancer profiling will reveal previously uncharacterized genetic heterogeneity of cancer and be beneficial in estimating patient prognosis and discovering novel cancer-related genes including therapeutic targets.

Phase II trial of temsirolimus (CCI-779) in recurrent glioblastoma multiforme: a North Central Cancer Treatment Group Study

BACKGROUND

Temsirolimus (CCI-779) is a small-molecule inhibitor of the mammalian target of rapamycin (mTOR) and represents a rational therapeutic target against glioblastoma multiforme (GBM).

METHODS

Recurrent GBM patients with < or = 1 chemotherapy regimen for progressive disease were eligible. Temsirolimus was administered in a 250-mg intravenous dose weekly.

RESULTS

Sixty-five patients were treated. The incidence of grade 3 or higher nonhematologic toxicity was 51%, and consisted mostly of hypercholesterolemia (11%), hypertriglyceridemia (8%), and hyperglycemia (8%). Grade 3 hematologic toxicity was observed in 11% of patients. Temsirolimus peak concentration (Cmax), and sirolimus Cmax and area under the concentration-time curve were decreased in patients receiving p450 enzyme-inducing anticonvulsants (EIACs) by 73%, 47%, and 50%, respectively, but were still within the therapeutic range of preclinical models. Twenty patients (36%) had evidence of improvement in neuroimaging, consisting of decrease in T2 signal abnormality +/- decrease in T1 gadolinium enhancement, on stable or reduced steroid doses. Progression-free survival at 6 months was 7.8% and median overall survival was 4.4 months. Median time to progression (TTP) for all patients was 2.3 months and was significantly longer for responders (5.4 months) versus nonresponders (1.9 months). Development of grade 2 or higher hyperlipidemia in the first two treatment cycles was associated with a higher percentage of radiographic response (71% v 31%; P = .04). Significant correlation was observed between radiographic improvement and high levels of phosphorylated p70s6 kinase in baseline tumor samples (P = .04).

CONCLUSION

Temsirolimus is well tolerated in recurrent GBM patients. Despite the effect of EIACs on temsirolimus metabolism, therapeutic levels were achieved. Radiographic improvement was observed in 36% of temsirolimus-treated patients, and was associated with significantly longer TTP. High levels of phosphorylated p70s6 kinase in baseline tumor samples appear to predict a patient population more likely to derive benefit from treatment. These findings should be validated in other studies of mTOR inhibitors.

Identification of Phosphopeptides by MALDI Q-TOF MS in Positive and Negative Ion Modes after Methyl Esterification

We have developed an efficient, sensitive, and specific method for the detection of phosphopeptides present in peptide mixtures by MALDI Q-TOF mass spectrometry. Use of the MALDI Q-TOF enables selection of phosphopeptides and characterization by CID of the phosphopeptides performed on the same sample spot. However, this type of experiment has been limited by low ionization efficiency of phosphopeptides in positive ion mode while selecting precursor ions of phosphopeptides. Our method entails neutralizing negative charges on acidic groups of nonphosphorylated peptides by methyl esterification before mass spectrometry in positive and negative ion modes. Methyl esterification significantly increases the relative signal intensity generated by phosphopeptides in negative ion mode compared with positive ion mode and greatly increases selectivity for phosphopeptides by suppressing the signal intensity generated by acidic peptides in negative ion mode. We used the method to identify 12 phosphopeptides containing 22 phosphorylation sites from low femtomolar amounts of a tryptic digest of beta-casein and alpha-s-casein. We also identified 10 phosphopeptides containing five phosphorylation sites from an in-gel tryptic digest of 100 fmol of an in vitro autophosphorylated fibroblast growth factor receptor kinase domain and an additional phosphopeptide containing another phosphorylation site when 500 fmol of the digest was examined. The results demonstrate that the method is a fast, robust, and sensitive means of characterizing phosphopeptides present in low abundance mixtures of phosphorylated and nonphosphorylated peptides.

Host-based antipoxvirus therapeutic strategies: turning the tables

The potential threat of the smallpox virus as a bioterror weapon has long been recognized, and the need for developing suitable countermeasures has become especially acute following the events of September 2001. Traditional antiviral agents interfere with viral proteins or functions. In a new study, Yang et al. focus instead on host cellular pathways used by the virus. A drug that interferes with the cellular ErbB-1 signal transduction pathway, activated by smallpox growth factor, sheds new light on how the virus replicates in the cell. Drugs that target the ErbB-signaling pathways represent a promising new class of antiviral agents.

Genetic alterations of phosphoinositide 3-kinase subunit genes in human glioblastomas

Genetic alterations of PI3K (phosphoinositide 3-kinase) subunits have been documented in a number of tumor types, with increased PI3K activity linked to gene amplification and mutation of catalytic subunits, as well as mutations of regulatory subunits. Among high grade gliomas, activation of the PI3K-AKT signaling pathway through loss of PTEN function is common. We therefore investigated whether genetic alteration of class IA PI3Ks might provide a mechanism for deregulation of this pathway in glioblastomas. We studied a series of glioblastomas with FISH to assess copy number of catalytic subunits (PIK3CA and PIK3CD) and with PCR-SSCP to screen for somatic mutations of conserved regions of both catalytic and regulatory subunits. FISH revealed frequent balanced copy number increases of both PIK3CA and PIK3CD, and one case showed an extra copy limited to PIK3CA. One glioblastoma exhibited a 9-bp deletion that encompassed the exon-intron junction of exon 12 of PIK3R1, documenting for the first time a mutation within a PI3K regulatory subunit in human glioblastoma. This deletion would be predicted to yield a truncated protein that lacks the inhibitory domain, resulting in increased PI3K activity. Furthermore, the case with selected PIK3CA copy number gain and the case with a truncating PIK3R1 mutation both featured AKT activation without PTEN mutation. These results suggest that genetic alterations of class IA PI3K subunit genes can occasionally play a role in human glioblastoma by activating the PI3K-AKT signaling pathway independently of PTEN mutation.

MDA-7 regulates cell growth and radiosensitivity in vitro of primary (non-established) human glioma cells

We examined the impact of purified bacterially synthesized GST-MDA-7 (IL-24) and ionizing radiation on the proliferation and survival of nonestablished human glioblastoma multiforme (GBM) cells. Glioma cell types expressing mutated PTEN and p53 molecules, activated ERBB1VIII, overexpressing wild type ERBB1 or without receptor overexpression were selected. In MTT assays, GST-MDA-7 caused a dose-dependent reduction in the proliferation of nonestablished glioma cells; however only at higher concentrations did GST-MDA-7 reduce cell viability. The anti-proliferative and cytotoxic effects of GST-MDA-7 were enhanced by radiation in a greater than additive fashion that correlated with JNK1/2/3 activation. The reduction in cell growth and enhancement in cell killing by the combination of GST-MDA-7 and radiation were blocked by an ROS scavenger, N-acetyl cysteine (NAC), a JNK1/2/3 inhibitor SP600125, a pan-caspase inhibitor (zVAD) and by an inhibitor of caspase 9 (LEHD), but not by an inhibitor of caspase 8 (IETD). Low concentrations of either GST-MDA-7 or radiation reduced clonogenic survival, however colony formation ability was significantly further decreased when the two treatments were combined, which was also blocked by inhibition of caspase 9 function. In general agreement with activation of the intrinsic caspase pathway, cell death correlated with reduced BCL-XL expression and with increased levels of the pro-apoptotic proteins BAD and BAX. Inhibition of caspase 9 after combination treatment blunted neither JNK1/2/3 activation nor the enhanced expression of BAD and BAX, but did block caspase 3 cleavage, reduced expression of BCL-XL and inhibition of ERK1/2 activity. In contrast, incubation with NAC blocked JNK1/2/3 activation and cell killing, but not the increases in BAD and BAX expression. These findings argue that after combination treatment JNK1/2/3 activation is a primary pro-apoptotic event and loss of BCL-XL expression and ERK1/2 activity are secondary caspase-dependent processes. This data also argues that GST- MDA-7 induces two parallel pro-apoptotic pathways via ROS-dependent and -independent mechanisms. Infection of primary human astrocytes with a recombinant adenovirus to express MDA-7, Ad.mda-7, but not infection with either Ad.cmv or Ad.mda-7SP- lacking MDA-7 secretion, resulted in the suppression of GBM cell colony formation in soft agar overlay assays, an effect that was enhanced in a greater than additive fashion by radiation. Collectively, our findings demonstrate that MDA-7 reduces proliferation and enhances the radiosensitivity of nonestablished human GBM cells in vitro, and when grown in 3 dimensions, and that sensitization occurs independently of basal EGFR/ERK1/2/AKT activity or the functions of PTEN and p53.

EGFR-independent activation of p38 MAPK and EGFR-dependent activation of ERK1/2 are required for ROS-induced renal cell death

2,3,5-Tris-(glutathion-S-yl)hydroquinone (TGHQ), a reactive metabolite of the nephrotoxicant hydroquinone, induces the ROS-dependent activation of MAPKs, followed by histone H3 phosphorylation and oncotic cell death in renal proximal tubule epithelial cells (LLC-PK(1)). Cell death and histone H3 phosphorylation are attenuated by pharmacological inhibition of p38 MAPK or ERK1/2 pathways. Because TGHQ, but not epidermal growth factor (EGF), induces histone H3 phosphorylation and cell death in LLC-PK(1) cells, we hypothesized that there are differences in the mechanisms by which TGHQ and EGF induce activation of the EGF receptor (EGFR). We therefore compared the relative ability of TGHQ, H(2)O(2), and EGF to activate EGFR and MAPKs and found that p38 MAPK activation is EGFR independent, whereas ERK1/2 activation occurs mainly through EGFR activation. TGHQ, H(2)O(2), and EGF induce different EGFR tyrosine phosphorylation profiles that likely influence the subsequent differential kinetics of MAPK activation. We next transfected LLC-PK(1) cells with a dominant negative p38 MAPK-expressing plasmid (pcDNA3-DNp38). TGHQ failed to induce phosphorylation of p38 MAPK and its substrate, MK-2, in pcDNA3-DNp38-transfected cells, indicating loss of function of p38 MAPK. In untransfected, pcDNA3 or pcDNA3-p38 (native)-transfected LLC-PK(1) cells, Hsp27 was intensively phosphorylated after TGHQ treatment, whereas in pcDNA3-DNp38-transfected cells, TGHQ failed to induce Hsp27 phosphorylation. Thus EGFR-independent p38 MAPK and EGFR-dependent ERK1/2 activation by TGHQ lead to the activation of two downstream signaling factors, i.e., histone H3 and Hsp27 phosphorylation, which have in common the potential ability to remodel chromatin.

Correlation of different markers (p53, EGF-R, c-erbB-2, Ki-67) expression in the diagnostic biopsies and the corresponding resected tumors in non-small cell lung cancer

Substaging using molecular markers has been proposed to try to identify prognostic factors allowing to define groups of patients with lung cancer for whom specific therapy might be of benefit. The pre-operative assessment of these markers seems to be important specially in case of neoadjuvant chemotherapy. The aim of our study was to compare the expression of two potential prognostic factors (p53 and Ki-67) and two potential therapeutic targets (EGF-R and c-erbB-2) assessed on biopsy samples (B) of non-small cell lung cancer (NSCLC) with that of the corresponding resected tumor (RT). The expression of these biological markers was evaluated by immunohistochemistry on B and on the paired RT in 28 patients. The mean percentage of p53 positive cells was 28% in RT and 38% in B with 81% CR between B and RT and 19% FP on B. Considering RT results as standard, the positive (PPV) and negative predictive value (NPV) of the B were, respectively, 74 and 100%. The mean percentage of EGF-R positive cells was 11% in RT and 28% in B. With a cut-off of 1%, we found 85% concordant results (CR) between B and RT, 4% false negative (FN) and 11% false positive (FP) on B. The PPV and NPV values of the B were, respectively, 80 and 92%. The 8% B and 19% RT were considered as positive for c-erbB-2. We found 15% FN and 4% FP on B with 81% CR between B and RT for c-erbB-2. The NPV of the B was 83%. The mean percentage of Ki-67 positive cells was 32% in RT and 14% in B. We found 82% CR between B and RT, 14% FN and 4% FP on B. The PPV of the B was 96%. In conclusion, biopsies may provide reliable information about p53, EGF-R, c-erbB-2 and Ki-67 in lung carcinoma and could help to elaborate a therapeutic strategy.

Constitutive EGFR signaling confers a motile phenotype to neural stem cells

The epidermal growth factor receptor (EGFR) has been shown to play an important role in brain development, including stem and precursor cell survival, proliferation, differentiation, and migration. To further examine the temporal and spatial requirements of erbB signals in uncommitted neural stem cells (NSCs), we expressed the ligand-independent EGF receptor, EGFRvIII, in C17.2 NSCs. These NSCs are known to migrate and to evince a tropic response to neurodegenerative environments in vivo but for which an underlying mechanism remains unclear. We show that enhanced erbB signaling via constitutive kinase activity of EGFRvIII in NSCs sustains an immature phenotype and enhances NSC migration.

Bile acids enhance the activity of the insulin receptor and glycogen synthase in primary rodent hepatocytes

Previously, we demonstrated that deoxycholic acid (DCA)-induced ERK1/2 and AKT signaling in primary hepatocytes is a protective response. In the present study, we examined the regulation of the phosphatidylinositol 3 (PI3) kinase/AKT/glycogen synthase (kinase) 3 (GSK3)/glycogen synthase (GS) pathway by bile acids. In primary hepatocytes, DCA activated ERBB1 (the epidermal growth factor receptor), ERBB2, and the insulin receptor, but not the insulin-like growth factor 1 (IGF-1) receptor. DCA-induced activation of the insulin receptor correlated with enhanced phosphorylation of insulin receptor substrate 1, effects that were both blocked by the insulin receptor inhibitor AG1024 and by expression of the dominant negative IGF-1 receptor (K1003R), which inhibited in trans. Expression of the dominant negative IGF-1 receptor (K1003R) also abolished DCA-induced AKT activation. Bile acid-induced activation of AKT and phosphorylation of GSK3 were blunted by the ERBB1 inhibitor AG1478 and abolished by AG1024. Bile acids caused activation of GS to a similar level induced by insulin (50 nM); both were blocked by inhibition of insulin receptor function and the PI3 kinase/AKT/GSK3 pathway. In conclusion, these findings suggest that bile acids and insulin may cooperate to regulate glucose storage in hepatocytes.

Clinical Utility of Fluorescence In Situ Hybridization (FISH) in Morphologically Ambiguous Gliomas with Hybrid Oligodendroglial/Astrocytic Features

Gliomas with hybrid oligodendroglial/astrocytic features are diagnostically problematic, and our ability to predict tumor behavior is limited. Some likely represent intermingled mixed oligoastrocytomas (MOAs), though precise diagnostic criteria and specific markers for this lesion are lacking. From the files at Washington University (1987-2000), 155 "ambiguous" glioma/intermingled MOA candidates were independently classified and graded by 5 neuropathologists, with consensus-derived pure oligodendrogliomas and astrocytomas excluded from further study. The 90 remaining cases (grades II = 29, III = 44, IV = 17) were analyzed by FISH on formalin-fixed, paraffin-embedded sections. Detectable deletions included combined 1p/19q (9%), solitary 19q (22%), PTEN/DMBT1 (26%), and p16 (32%). EGFR amplification was found in 11%. Patients were followed until death (47%) or a median of 3.3 years. Similar to prior glioma series, patient age (p < 0.0001) and tumor grade (p < 0.0001) were strongly associated with survival times. EGFR amplification (p = 0.0007) and deletions of PTEN/ DMBT1 (p = 0.016) or p16 (p = 0.014), either individually or as a group (p = 0.04), portended a shorter median survival compared with tumors lacking these alterations. We conclude that 1) distinct genetic subsets are identifiable by FISH in morphologically ambiguous gliomas, and 2) both histological grading and molecular analysis yield prognostically useful information.

Increased expression of Mcl-1 is responsible for the blockage of TRAIL-induced apoptosis mediated by EGF/ErbB1 signaling pathway

Epidermal growth factor (EGF) protects against death receptor induced apoptosis in epithelial cells. Herein, we demonstrate that EGF protection against tumor necrosis factor related apoptosis-inducing ligand (TRAIL) induced apoptosis is mediated by increased expression of the Bcl-2 family member myeloid cell leukemia 1 (Mcl-1). EGF increased the mRNA and protein levels of Mcl-1. Furthermore, expression of ErbB1 alone or in combination with ErbB2 in NIH3T3 cells up-regulates Mcl-1 following EGF treatment. In addition, up-regulation of Mcl-1 by EGF is mediated through AKT and NFkappaB activation since kinase inactive AKT and DeltaIkappaB effectively blocks this up-regulation. NFkappaB was also critical for the ability of EGF to prevent TRAIL induced apoptosis as a dominant negative IkappaB (DeltaIkappaB) blocked NFkappaB activation, and relieved EGF protection against TRAIL mediated mitochondrial cytochrome-c release and apoptosis. Finally, anti-sense oligonucleotides directed against Mcl-1 effectively reduced the protein levels of Mcl-1 and blocked EGF protection against TRAIL induced mitochondrial cytochrome-c release and apoptosis. Taken together, EGF signaling leads to increased Mcl-1 expression that is required for blockage of TRAIL induced apoptosis.

Investigation of ErbB1 and ErbB2 expression for therapeutic targeting in primary liver tumours

BACKGROUND

Molecular targets are needed for primary liver tumours.

AIMS

ErbB1 and ErbB2 expression was analysed in neoplastic and surrounding tissue in surgical specimens from 52 hepatocellular carcinomas and 48 intrahepatic cholangiocarcinomas, randomly chosen from cases surgically treated in this institution.

METHODS

ErbB1 and ErbB2 expression were evaluated immunohistochemically, the latter by Herceptest. Gene amplification of ErbB2 was tested by chromogenic in situ hybridisation.

RESULTS

In normal/cirrhotic non-neoplastic tissue, the ErbB1 (but not ErbB2) antibody commonly stained normal hepatocytes and mature intrahepatic ducts. In neoplastic tissue, moderate/strong ErbB1 immunostaining occurred in 43/52 (85%) hepatocellular carcinomas and 39/48 (81%) intra-hepatic cholangiocarcinomas. With ErbB2 Herceptest, 0/52 (0%) hepatocellular carcinomas and 2/48 (4%) intra-hepatic cholangiocarcinomas had treatable scores of 2+/3+ (chromogenic in situ hybridisation confirmed gene amplification in the latter two cases only). Neither ErbB1 nor ErbB2 expression correlated with any of the main clinical-pathologic features or survival.

CONCLUSIONS

Although not related to prognosis, ErbB1 could be a molecular target in a large percentage of patients with hepatocellular carcinoma or intrahepatic cholangiocarcinoma. Inclusion of anti-ErbB1 drugs such as ZD 1839 and c225 (and possibly also anti-ErbB2 drugs like Trastuzumab for a small subset of patients) in clinical trials is suggested.

Molecular biology of glioma tumorigenesis

Gliomas are the most common intracranial malignant tumors in humans, and high-grade gliomas in particular pose a unique challenge due to their propensity for proliferation and tissue invasion. Our understanding of glioma oncogenesis, proliferation, and invasion has been greatly advanced in the past 10 years as researchers have gained a better understanding of the molecular biology of these tumors. This article highlights glioma histopathology, as well as cytogenetic and molecular alterations associated with the pathogenesis of human gliomas. It is hoped that better understanding of the molecular pathogenesis of gliomas will improve tumor classification as well as lead to novel targets for therapy and prognostic markers.

Molecular characterization as a target for cancer therapy in relation to orphan status disorders (Review)

The long-term effort in investigating chemical methods to eliminate only cancer cells has improved our knowledge and has led to the development of new drugs. The targets for cancer treatment may be large polymeric molecules such as DNA or microtubules as well as regulatory pathways for tumor development and cell survival preservation or tyrosine kinase activity. Examples of new agents are: trastuzumab (Herceptin), a humanized monoclonal antibody that blocks the HER-2/neu proto-oncogene in combination with cytotoxic agents, is used in a percentage of breast cancer patients; signal transduction inhibitor of abl tyrosine kinase STI 571 (Glivec) has been shown to be an active treatment for chronic myeloid leukemia and GISTs; epidermal growth factor receptors in certain tumors have been targeted with agents such as C225 (Cetuximab) and ZD 1839 (IRESSA); an adenosine deaminase analogue of deoxyadenosine, Cladribine (2-chloro-2 deoxy-adenosine) has shown high effectiveness in hairy-cell leukemia and the multitargeted antifolate (Premetrexed) and several vaccines have been studied and are in clinical trials for resistant cancers. These new drug developments represent a promising field for future cancer management.

MRI of transgene expression: correlation to therapeutic gene expression

Magnetic resonance imaging (MRI) can provide high-resolution 3D maps of structural and functional information, yet its use of mapping in vivo gene expression has only recently been explored. A potential application for this technology is to noninvasively image transgene expression. The current study explores the latter using a nonregulatable internalizing engineered transferrin receptor (ETR) whose expression can be probed for with a superparamagnetic Tf-CLIO probe. Using an HSV-based amplicon vector system for transgene delivery, we demonstrate that: 1) ETR is a sensitive MR marker gene; 2) several transgenes can be efficiently expressed from a single amplicon; 3) expression of each transgene results in functional gene product; and 4) ETR gene expression correlates with expression of therapeutic genes when the latter are contained within the same amplicon. These data, taken together, suggest that MRI of ETR expression can serve as a surrogate for measuring therapeutic transgene expression.

Effect of duration of fixation on quantitative reverse transcription polymerase chain reaction analyses

Increasingly, there is the need to analyze gene expression in tumor tissues and correlate these findings with clinical outcome. Because there are few tissue banks containing enough frozen material suitable for large-scale genetic analyses, methods to isolate and quantify messenger RNA (mRNA) from formalin-fixed, paraffin-embedded tissue sections are needed. Recovery of RNA from routinely processed biopsies and quantification by the polymerase chain reaction (PCR) has been reported; however, the effects of formalin fixation have not been well studied. We used a proteinase K-salt precipitation RNA isolation protocol followed by TaqMan quantitative PCR to compare the effect of formalin fixation for 24, 48, and 72 hours and for 1 week in normal (2), oral epithelial dysplasia (3), and oral squamous cell carcinoma (4) specimens yielding 9 fresh and 36 formalin-fixed samples. We also compared mRNA and protein expression levels using immunohistochemistry for epidermal growth factor receptor (EGFR), matrix metalloproteinase (MMP)-1, p21, and vascular endothelial growth factor (VEGF) in 15 randomly selected and routinely processed oral carcinomas. We were able to extract RNA suitable for quantitative reverse transcription (RT) from all fresh (9/9) and formalin-fixed (36/36) specimens fixed for differing lengths of time and from all (15/15) randomly selected oral squamous cell carcinoma. We found that prolonged formalin fixation (>48 h) had a detrimental effect on quantitative RT polymerase chain reaction results that was most marked for MMP-1 and VEGF but less evident for p21 and EGFR. Comparisons of quantitative RT polymerase chain reaction and immunohistochemistry showed that for all markers, except p21, there was good correlation between mRNA and protein levels. p21 mRNA was overexpressed in only one case, but protein levels were elevated in all but one tumor, consistent with the established translational regulation of p21. These results show that RNA can be reliably isolated from formalin-fixed, paraffin-embedded tissue sections and can produce reliable quantitative RT-PCR data. However, results for some markers are adversely affected by prolonged formalin fixation times.

Intra-arterial delivery of p53-containing adenoviral vector into experimental brain tumors

Human tumor xenografts established in athymic rat brains were used to determine the feasibility of intravascular delivery of tumor suppressor genes to brain tumors. Both tumor size and number were compared to characterize the effect of tumor burden on tumor transduction efficacy by a control LacZ-containing adenoviral vector. Experiments with tumors grown in vivo for either 3, 5, or 7 days demonstrated that 5-day-old tumors provided the best target for vector infection and transgene expression by this mode of administration. Intra-arterial mannitol facilitated transduction efficiency. Tumor burden did not seem to affect transduction, while tumor location appeared to be an important factor. Based on these results, intra-arterial infusion of a p53-containing adenoviral vector was carried out and resulted in significant retardation of brain tumor growth 3 days after administration. Effects at longer time points were not as significant. These findings indicate that intra-arterial administration of adenoviral vectors containing p53 is efficient and can result in changes in tumor size, but that long-term control of tumor growth may require multiple adenoviral treatments.

Novel approaches to the treatment of non-small cell lung cancer

Prognosis of non-small cell lung carcinomas (NSCLC) remains poor, especially in advanced disease. The introduction of new cytotoxic agents in the past decade did only attain minor improvements in survival. It is rather clear that chemotherapy may have reached a plateau, and that it will be difficult to obtain better results in advanced NSCLC by chemotherapy alone. Novel treatment modalities are urgently needed in advanced NSCLC. Backed-up by advances in the understanding of tumor cell biology, a new generation of anticancer agents specifically directed at targets such as tyrosine kinases, farnesyl transferase, angiogenesis factors, matrixmetalloproteinases and oncogenes has been developed in recent years. In this review, we give a brief summary of the state-of-the-art treatment of NSCLC, highlighting its limitations. Novel systemic approaches are then discussed in detail with focus on their mechanistic rationale, stage of clinical development and possible drawbacks. Finally, perspectives of future applications and impact on the treatment of NSCLC are also discussed.

EGFR-mediated cell cycle regulation

Cancer is a disease of uncontrolled cell proliferation. The cell cycle provides a crucial platform for coordination between proliferation and cell death. Somatic cells undergo replication and division by traversing the tightly regulated cell cycle. Growth factors play a critical role in initiating signaling events stimulating cell cycle progression, which is crucial for their mitogenic and tumorigenic effects. Epidermal growth factor receptor (EGFR) and its ligands are frequently upregulated in human cancers. The oncogenic effects of EGFR include initiation of DNA synthesis, enhanced cell growth, invasion, and metastasis. Specific abrogation of EGFR results in cell cycle arrest, apoptosis, or dedifferentiaton of cancer cells. Downregulation of EGFR signaling has therapeutic benefit in preclinical and clinical studies. Therefore, better understanding of the mechanisms of regulation and coordination between the cell cycle, cell growth, and cell death will lead to the development of novel cancer therapies.

Enhanced antitumor effect of EGF R-targeted p21WAF-1 and GM-CSF gene transfer in the established murine hepatoma by peritumoral injection

One of the major obstacles in current cancer gene therapy is the lack of a gene delivery system with high efficiency and targetability. In this paper, a nonviral gene delivery system GE7, which was designed to target EGF receptor (EGF R) overexpressed on the surface of cancer cel Is through an EGF R-binding oligopeptide (GE7), was used for in vivo gene therapy in a murine subcutaneous hepatoma model. It was demonstrated that the GE7 system could target the reporter gene beta-gal to EGF R-expressing hepatoma cells with high efficiency after in vitro transfection and in vivo peritumoral injection. To improve the therapeutic effect elicited by single gene transfer, human cyclin-dependent kinase inhibitor gene p21WAF-1 and murine cytokine gene GM-CSFwere used simultaneously in peritumoral injection of the GE7/DNA polyplex. The results showed that combined gene transfer of p21WAF-1 and GM-CSF could inhibit the growth of pre-established tumor more effectively and prolong the survival time of hepatoma-bearing mice more significantly than the transfer of a single gene. Apoptosis in the tumor tissues were found when injected with the p21WAF1-DNA polyplex. Prominent inflammatory infiltration was observed in the tumor tissue transfected with the GM-CSF DNA polyplex. Our data demonstrate that the GE7 system-mediated, EGF R-targeted cotransfer of p21WAF-1 and GM-CSF genes exhibit more potent antitumor effect by inducing tumor cell apoptosis and inflammatory responses.

KUB3 amplification and overexpression in human gliomas

Gene amplification is known to occur frequently in human glioma. Recently we reported cloning of a novel gene termed glioma-amplified sequence 16 (GAS16) by microdissection-mediated cDNA capture. In this article, we demonstrate that GAS16 results from an alternative splicing process of the Ku70 binding protein 3 (KUB3) that is essential for DNA double-strand break repair. The alternative splice product was found in glioblastoma and in normal fetal brain. We determined the amplification frequency of KUB3 in glioma with different grading. We analyzed a total of 102 glioma primary tumors and found KUB3 to be amplified in 12/82 (14%) glioblastomas, 4/13 anaplastic astrocytomas (30%), and 2/4 astrocytomas, but in none of three pilocytic astrocytomas. Northern blot analysis of glioblastoma shows a strong correlation between KUB3 amplification and overexpression. Amplification of KUB3 appears to be independent of other genetic changes frequently associated with the development of gliomas, including EGFR amplification, LOH of TP53, and LOH of chromosome 10. The KUB3 amplification and overexpression may interfere with the function of KUB3 in the DNA-PK complex involved in the maintenance of genome stability and reduction of mutation frequency.

Chromosome 7 aneusomy. A marker for metastatic melanoma? Expression of the epidermal growth factor receptor gene and chromosome 7 aneusomy in nevi, primary malignant melanomas and metastases

Receptor tyrosine kinases such as the epidermal growth factor receptor (EGFR) play an important role in a variety of malignant neoplasias, making the search for aberrations in the relevant chromosomes an important issue. Differential expression of the EGFR gene was investigated by reverse transcriptase (RT)-PCR on tissue samples of normal skin, nevi, primary melanomas, and melanoma metastases. The EGFR gene is located on chromosome 7p12.3-p12.1. To determine the number of chromosomes 7 in cell nuclei of the mentioned tissue samples we performed fluorescence in situ hybridization (FISH) on touch preparations, using a DNA probe that hybridizes specifically to the centromeric region of chromosome 7. Additionally, chromosome 7 number in interphase nuclei was determined in short-term primary cell cultures of nevi, primary melanomas, and metastases. The highest EGFR gene expression frequency was found in melanoma metastases. By FISH we detected the highest fraction of cell nuclei with more than two chromosomes 7 in the group of metastases. Our results suggest that overexpression of the EGFR gene might play an important role in metastasis of malignant melanoma. This is well reflected by polysomy 7, possibly accounting for an increased EGFR gene copy number.

Cyclooxygenase-2 is overexpressed in human cervical cancer

Multiple lines of evidence suggest that cyclooxygenase-2 (COX-2) is an important target for preventing epithelial malignancies. Little is known, however, about the expression of COX-2 in gynecological malignancies. By immunoblot analysis, COX-2 was detected in 12 of 13 cases of cervical cancer but was undetectable in normal cervical tissue. Immunohistochemistry revealed COX-2 in malignant epithelial cells. COX-2 was also expressed in cervical intraepithelial neoplasia. The mechanism by which COX-2 is up-regulated in cervical cancer is unknown. Because the epidermal growth factor (EGF) receptor is commonly overexpressed in cervical cancer, we investigated whether EGF could induce COX-2 in cultured human cervical carcinoma cells. Treatment with EGF markedly induced COX-2 protein, COX-2 mRNA, and stimulated COX-2 promoter activity. The induction of COX-2 by EGF was suppressed by inhibitors of tyrosine kinase activity, phosphatidylinositol 3-kinase, mitogen-activated protein kinase kinase, and p38 mitogen-activated protein kinase. Moreover, overexpressing dominant-negative forms of extracellular signal-regulated kinase 1, c-Jun NH2-terminal kinase, p38, and c-Jun blocked EGF-mediated induction of COX-2 promoter activity. Taken together, these findings suggest that deregulation of the EGF receptor signaling pathway may lead to enhanced COX-2 expression in cervical cancer.