Effects of FGFR inhibitors TKI258, BGJ398 and AZD4547 on breast cancer cells in 2D, 3D and tissue explant cultures.

PURPOSE: Fibroblast growth factor receptors (FGFR) and pathways are important players in breast cancer (BC) development. They are commonly altered, and BCs exhibiting FGFR gene amplification are currently being studied for drug development. Here, we aimed to compare the effects of three FGFR inhibitors (FGFRis), i.e., non-selective TKI258 and selective BGJ398 and AZD4547, on different BC-derived cell lines (BCCs) and primary tissues. METHODS: The human BCCs MCF-7 and MDA-MB-231(SA) (wild-type FGFR) and MFM223 (amplified FGFR1 and FGFR2) were analyzed for FGFR expression using qRT-PCR, and the effects of FGFRis on FGFR signaling by Western blotting. The effects of FGFRis on proliferation, viability, migration and invasion of BCCs were assessed in 2D cultures using live-cell imaging, and in 3D cultures using phenotypic analysis of organoids. To study radio-sensitization, FGFRi treatment was combined with irradiation. Patient-derived BC samples were treated with FGFRis in explant cultures and immunostained for Ki67 and cleaved caspase 3. RESULTS: We found that all FGFRis tested decreased the growth and viability of BC cells in 2D and 3D cultures. BGJ398 and AZD4547 were found to be potent at low concentrations in FGFR-amplified MFM233 cells, whereas higher concentrations were required in non-amplified MCF7 and MDA-MB-231(SA) cells. TKI258 inhibited the migration and invasion, whereas BGJ398 and AZD4547 only inhibited the invasion of MDA-MB-231(SA) cells. FGFRi treatment of MCF7 and MFM223 cells enhanced the inhibitory effect of radiotherapy, but this effect was not observed in MDA-MB-231(SA) cells. FGFRi-treated primary BC explants with moderate FGFR levels showed a tendency towards decreased proliferation and increased apoptosis. CONCLUSIONS: Our results indicate that, besides targeting FGFR-amplified BCs with selective FGFRis, also BCs without FGFR amplification/activation may benefit from FGFRi-treatment. Combination with other treatment modalities, such as radiotherapy, may allow the use of FGFRis at relatively low concentrations and, thereby, contribute to better BC treatment outcomes.

Proteomic analysis reveals successive aberrations in protein expression from healthy mucosa to invasive head and neck cancer.

Development of head and neck squamous cell carcinoma (HNSCC) is a multistep process and in many cases involves a phenomenon coined 'field cancerization'. In order to identify changes in protein expression occurring at different stages of tumorigenesis and field cancerization, we analysed 113 HNSCCs and 73 healthy, 99 tumor-distant and 18 tumor-adjacent squamous mucosae by SELDI-TOF-MS on IMAC30 ProteinChip Arrays. Forty-eight protein peaks were differentially expressed between healthy mucosa and HNSCC. Calgizarrin (S100A11), the Cystein proteinase inhibitor Cystatin A, Acyl-CoA-binding protein, Stratifin (14-3-3 sigma), Histone H4, alpha- and beta-Hemoglobin, a C-terminal fragment of beta-hemoglobin and the alpha-defensins 1-3 were identified by mass spectrometry. The alpha-defensins showed various alterations in expression as validated by immunohistochemistry (IHC). Supervised prediction analysis revealed excellent classification of healthy mucosa (94.5% correctly classified) and tumor samples (92.9% correctly classified). Application of this classifier to the tumor-adjacent and tumor-distant mucosa samples disclosed dramatic changes: only 59.6% of the tumor-distant biopsies were classified as normal, 27.3% were predicted as aberrant or HNSCC. Strikingly, 72% of the tumor-adjacent mucosae were predicted as aberrant. These data provide evidence for the existence of genetically altered fields with inconspicuous histology. Comparison of the protein profiles in the tumor-distant-samples with clinical outcome of 32 patients revealed a significant association between aberrant profiles with tumor relapse events (P=0.018; Fisher's exact test, two-tailed). We conclude that proteomic profiling in conjunction with protein identification greatly outperforms histopathological diagnosis and may have significant predictive power for clinical outcome and personalized risk assessment.

Targeted disruption of the epidermal growth factor receptor inhibits development of papillomas and carcinomas from human papillomavirus-immortalized keratinocytes.

The epidermal growth factor receptor (EGF-R) is frequently overexpressed in human papillomavirus (HPV)-associated dysplasias and carcinomas, implying that it is important for the progression of keratinocytes to malignancy. We used mice with a targeted disruption of the EGF-R gene to directly examine its role in cell immortalization and tumor development. Epidermal keratinocytes were cultured from EGF-R knockout, heterozygous, and wild-type mice, infected with retroviruses encoding HPV-16 E6 and E7 oncogenes, and grafted to nude mice. E6/E7 induced immortalization of EGF-R wild-type cells 5-fold more efficiently than null cells. Immortal EGF-R null cells grew more slowly, achieved a lower saturation density, and were more sensitive to apoptosis than the immortalized wild-type or heterozygous cells. Analyses using cDNA expression arrays showed that EGF-R null cells expressed increased levels of RNAs encoding p21waf and insulin-like growth factor-binding protein-2. EGF-R-positive immortal keratinocytes formed papillomas in 17% (15 of 90) of skin grafts, and seven grafts progressed to squamous carcinoma after 6-12 months. EGF-R null keratinocytes did not form papillomas, but 1 of 96 grafts progressed to a squamous carcinoma after 1 year. However, treatment with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate induced tumors in 18 and 35% of grafts containing EGF-R null or EGF-R-positive cells, respectively. Transduction with an activated v-Ha-ras gene, which signals downstream of the EGF-R, induced rapidly growing carcinomas in all grafts regardless of EGF-R genotype. These results directly show that the EGF-R is important, but not essential, for immortalization by HPV and for progression of immortal cells to papillomas and carcinomas.

Human papillomavirus type 16 E6 and E7 proteins inhibit differentiation-dependent expression of transforming growth factor-beta2 in cervical keratinocytes.

Infection with high-risk human papillomaviruses (HPVs) represents a major risk factor for the development of cervical cancer. The HPV-16 E6 and E7 proteins are highly expressed in differentiating keratinocytes, where they inactivate the p53 and retinoblastoma (pRb) proteins, two important transcriptional regulators. We have used cDNA expression arrays to identify global alterations in gene expression induced by E6 and E7 in differentiating cultures of human cervical keratinocytes. We show that E6 and E7 decrease expression of TGF-beta2 mRNA and alter expression of multiple TGF-beta-responsive genes involved in cell cycle regulation, apoptosis, and tissue remodeling. E6 and E7 inhibited expression of TGF-beta2 RNA 7-fold (relative effectiveness, E6/ E7 > E6 > E7 > control) and decreased secretion of biologically active TGF-beta2 by 70-80% (reduced from 70 to 10 pg/10(6) cells/24 h). Downregulation occurred through p53- and pRb-dependent pathways. In contrast, E6 and E7 did not alter expression of TGF-beta1 and TGF-beta3. Down-regulation of TGF-beta2 was biologically relevant because the addition of recombinant cytokine (10-200 pg/ml) to E6/E7-expressing cells restored expression of TGF-P-responsive genes, inhibited growth of keratinocytes, and decreased immortalization by E6 and E7. These results suggest that TGF-32- and TGF-3-responsive genes are important targets for the HPV-16 E6 and E7 oncoproteins in differentiating cervical keratinocytes.

Expression of mutated p53 occurs in tumor-distant epithelia of head and neck cancer patients: a possible molecular basis for the development of multiple tumors.

As in most other tumor types, expression of mutated or phenotypically altered p53 is a common occurrence in head and neck carcinogenesis. Since the prognosis for many head and neck tumor patients is severely affected by the occurrence of multiple primary and secondary tumors, we have analyzed the phenotype and genotype of p53 in squamous and respiratory epithelia either adjacent to or at significant distance from the primary tumors. Many tumor patients showed multifocal overexpression of the p53 protein in a variety of these epithelia. Overexpression of p53 correlated with increased proliferation and dedifferentiation, as demonstrated by immunohistochemistry and in situ hybridization using histone H3 and cytokeratin-specific probes. Polymerase chain reaction-single-strand conformation polymorphism analysis and sequencing of p53 DNA, amplified from these biopsies after immunostaining and microdissection, confirmed and extended these findings. We have identified different mutations in p53 in different tumor-distant epithelia from the same patients. The data indicate that mutation of p53 is an early event in head and neck carcinogenesis, preceding signs of overt neoplasia, and that different mutations in p53 in multiple foci may provide a molecular basis for the development of multiple tumors.

Heat-shock factor 2 is a suppressor of prostate cancer invasion.

Heat-shock factors (HSFs) are key transcriptional regulators in cell survival. Although HSF1 has been identified as a driver of carcinogenesis, HSF2 has not been explored in malignancies. Here, we report that HSF2 suppresses tumor invasion of prostate cancer (PrCa). In three-dimensional organotypic cultures and the in vivo xenograft chorioallantoic membrane model HSF2 knockdown perturbs organoid differentiation and promotes invasiveness. Gene expression profiling together with functional studies demonstrated that the molecular mechanism underlying the effect on tumor progression originates from HSF2 steering the switch between acinar morphogenesis and invasion. This is achieved by the regulation of genes connected to, for example, GTPase activity, cell adhesion, extracellular matrix and actin cytoskeleton dynamics. Importantly, low HSF2 expression correlates with high Gleason score, metastasis and poor survival of PrCa patients, highlighting the clinical relevance of our findings. Finally, the study was expanded beyond PrCa, revealing that the expression of HSF2 is decreased in a wide range of cancer types. This study provides the first evidence for HSF2 acting as a suppressor of invasion in human malignancies.

Identification of novel molecular markers which correlate with HPV-induced tumor progression.

High risk HPVs (human papillomaviruses) are causally involved in the development of cervical cancer. However, other factors, such as somatic genetic alterations also play a decisive role in malignant conversion of cervical keratinocytes. Mutations and chromosomal aberrations are known to influence the pattern of gene expression. Therefore we used the recently developed RT-PCR based method of differential display of mRNAs to detect differences in gene expression which correlate with tumorigenicity. Non-tumorigenic HPV16-immortalized human foreskin keratinocytes (HPK IA) were compared with their tumorigenic counterparts and 49 different genes were identified which were either up- or downregulated. The identified genes encode proteins of the cytoskeleton and the extracellular matrix, the nuclear splicing apparatus, transcription regulators and membrane-associated proteins. The expression pattern of all genes was also examined by RNA-RNA in situ hybridization in biopsies of normal cervical epithelium, precancerous lesions and cancers. Two genes, C4.8 and C21.7, are of particular interest because their expression is upregulated in a subset of high grade precancerous lesions and in over 58% of cancers. These two genes may therefore be considered as putative progression markers. C4.8 is a new member of the transmembrane 4 (TM-4) protein family which includes tumor-associated antigens such as CD63 and TAPA-1, whereas C21.7 shows no significant homologies to any known genes or proteins.

Overexpression of p53 in tumor-distant epithelia of head and neck cancer patients is associated with an increased incidence of second primary carcinoma.

Second primary carcinoma is a peculiar feature of head and neck cancer and represents a form of treatment failure distinct from the recurrence of the primary tumor. Whether altered p53 expression in tumor-distant epithelia at the time of diagnosis is of clinical value as a biomarker for second primary carcinoma development has not been rigorously answered because of the lack of long-term follow-up studies involving a sufficiently large patient cohort. In this prospective study, we have investigated p53 expression in tumor-distant epithelia and in the corresponding primary tumors of 105 head and neck cancer patients by immunohistochemistry on frozen sections. After a median follow-up of 55 months, the clinical course of disease parameters, i.e., local recurrences, lymph node and distant metastasis, incidence of second primary carcinoma, and survival, was evaluated. Overexpression of p53 in tumor-distant epithelia was found in 49 patients (46.7%), and it was independent of the p53 protein status of the primary tumor and of the tumor site, size, stage, and grading. Mucosal p53 overexpression was not associated with local primary recurrences, lymph node or distant metastases, or overall survival. Importantly, mucosal p53 overexpression, but not overexpression in the primary tumors, was significantly associated with an increased incidence of second primary carcinomas (P = 0.0001; Fisher's exact test). When the times to second primary tumor occurrence were analyzed by the Kaplan-Meier method, the difference remained significant (P = 0.005; log rank test). We conclude that IHC staining for p53 overexpression in tumor-distant epithelia provides a simple and rapid tool to identify head and neck cancer patients at increased risk of developing second primary tumors. Because p53 overexpression in these epithelia in our patient cohort was specifically associated with second primary cancer but not with recurrences, at least a fraction of the second primary cancers appears to have resulted from genetic events in the mucosa ("field cancerization").

Microarrays: spotlight on gene function and pharmacogenomics.

The introduction of microarray technology has dramatically changed the way that researchers address many biomedical questions. DNA microarrays can measure expression of thousands of genes simultaneously, providing extensive information on gene interaction and function. Microarray technology is a powerful tool for identifying novel molecular drug targets and for elucidating mechanisms of drug action. Furthermore, microarrays can monitor the global profile of gene expression in response to specific pharmacologic agents, providing information on drug efficacy and toxicity. Over the last several years, dramatic advancements have occurred in array technology. In this review we describe basic aspects of microarray instrumentation and experimentation. Each of the major array formats including oligonucleotides arrays, spotted arrays, and macroarrays are examined, and advantages and options for using each format are presented. Important factors in the design and analysis of microarray experiments are also discussed. Most importantly, we explore recent developments in microarray technology that are relevant to pharmacogenomics and the discovery of gene function.

c-fos expression in noradrenergic A2 neurons of the rat during the estrous cycle and after steroid hormone treatments.

The expression of the proto-oncogene product fos in noradrenergic neurons of the A2 cell group was studied with immunohistochemistry during the estrous cycle of the rat and after ovariectomy and estrogen treatments. During the estrous cycle the percentage of fos-positive norepinephrine containing neurons was highest at proestrus (39%), followed by estrus (36%) while during diestrus only 4% of the A2 neurons contained immunoreactive fos protein in their nuclei. Ovariectomy caused a further decrease in the number of fos-positive A2 neurons (2%) while long-term estradiol administration partially reversed the effects of ovarian steroid removal (19%). However, 3 h after a single subcutaneous injection of estradiol into ovariectomised rats, 79% of the noradrenergic neurons in the A2 area showed fos immunoreactivity in their nuclei. The results indicate that fos-expression in the noradrenergic neurons in the A2 region varies depending upon the circulating estradiol levels. Since norepinephrine stimulates gonadotropin releasing hormone (GnRH) secretion from the median eminence during proestrus and the GnRH neurons do not contain estrogen receptors, it is suggested that the A2 region is, at least in part, responsible for conveying the estrogen signal to the GnRH neurons.

Readability and histological biocompatibility of microchip transponders in horses.

Identification of horses by microchip transponder is mandatory within the European Union with only a few exceptions. In this study, the readability of such microchips in 428 horses with three different scanners (A, B and C) and the histological changes at the implantation site in 16 animals were assessed. Identification of microchips differed between scanners (P<0.001), and with 'side of neck' (P<0.001). Scanners A, B and C identified 93.5%, 89.7% and 100% of microchips, respectively, on the 'chip-bearing' side of the neck. From the contralateral side, scanners A, B and C identified 21.5%, 26.9% and 89.5% of transponders, respectively. Microchip readability was affected by age (P<0.001), but not by breed of horse. At necropsy, transponders were found in the subcutaneous fat (n=3), inter- or peri-muscular connective tissue (n=8), or musculature (n=5), where they were surrounded by a fibrous capsule ranging in thickness from 12.7 to 289.5 µm in 15 animals. In two animals, immature granulation tissue with attendant granulomatous inflammation, and a granulomatous myositis, surrounding the microchip were identified, respectively. Severe (n=1), moderate (n=1), and mild (n=3) lymphohistiocytic inflammation was noted within the fibrous capsule. Microchip transponders were found to be a highly reliable and biocompatible method of horse identification.

Readability of branding symbols in horses and histomorphological alterations at the branding site.

Identification of horses has traditionally been facilitated by hot iron branding, but the extent by which branding symbols and numbers can be identified has not been investigated. The local pathological changes induced by branding are also unknown. This study analysed the readability of branding symbols and histomorphological alterations at the branding sites. A total of 248 horses in an equestrian championship were available for identification of symbols and numbers. A further 28 horses, euthanased for other reasons, provided histological examination of the branding site. All except one horse had evidence of histological changes at the brand site, including epidermal hyperplasia, increase of dermal collagenous fibrous tissue and loss of adnexal structures. In two foals, an ulcerative to necrotizing dermatitis was observed and interpreted as a complication of recent branding lesions. Despite the fact that hot iron branding caused lesions compatible with third degree thermal injury, it did not allow unambiguous identification of a large proportion of older horses. While the breed-specific symbol was consistently identified by three independent investigators in 84% of the horses, the double-digit branding number was read correctly by all three investigators in less than 40%. In conclusion, hot iron branding in horses causes lesions compatible with third degree thermal injury but does not always allow identification of horses.

Lysophosphatidic acid and sphingosine-1-phosphate promote morphogenesis and block invasion of prostate cancer cells in three-dimensional organotypic models.

Normal prostate and some malignant prostate cancer (PrCa) cell lines undergo acinar differentiation and form spheroids in three-dimensional (3-D) organotypic culture. Acini formed by PC-3 and PC-3M, less pronounced also in other PrCa cell lines, spontaneously undergo an invasive switch, leading to the disintegration of epithelial structures and the basal lamina, and formation of invadopodia. This demonstrates the highly dynamic nature of epithelial plasticity, balancing epithelial-to-mesenchymal transition against metastable acinar differentiation. This study assessed the role of lipid metabolites on epithelial maturation. PC-3 cells completely failed to form acinar structures in delipidated serum. Adding back lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) rescued acinar morphogenesis and repressed invasion effectively. Blocking LPA receptor 1 (LPAR1) functions by siRNA (small interference RNA) or the specific LPAR1 inhibitor Ki16425 promoted invasion, while silencing of other G-protein-coupled receptors responsive to LPA or S1P mainly caused growth arrest or had no effects. The G-proteins Gα(12/13) and Gα(i) were identified as key mediators of LPA signalling via stimulation of RhoA and Rho kinases ROCK1 and 2, activating Rac1, while inhibition of adenylate cyclase and accumulation of cAMP may be secondary. Interfering with these pathways specifically impeded epithelial polarization in transformed cells. In contrast, blocking the same pathways in non-transformed, normal cells promoted differentiation. We conclude that LPA and LPAR1 effectively promote epithelial maturation and block invasion of PrCa cells in 3-D culture. The analysis of clinical transcriptome data confirmed reduced expression of LPAR1 in a subset of PrCa's. Our study demonstrates a metastasis-suppressor function for LPAR1 and Gα(12/13) signalling, regulating cell motility and invasion versus epithelial maturation.

Systematic knockdown of epigenetic enzymes identifies a novel histone demethylase PHF8 overexpressed in prostate cancer with an impact on cell proliferation, migration and invasion.

Our understanding of key epigenetic regulators involved in specific biological processes and cancers is still incomplete, despite great progress in genome-wide studies of the epigenome. Here, we carried out a systematic, genome-wide analysis of the functional significance of 615 epigenetic proteins in prostate cancer (PrCa) cells. We used the high-content cell-spot microarray technology and siRNA silencing of PrCa cell lines for functional screening of cell proliferation, survival, androgen receptor (AR) expression, histone methylation and acetylation. Our study highlights subsets of epigenetic enzymes influencing different cancer cell phenotypes. Plant homeo domain (PHD) finger proteins have a key role in cell survival and histone methylation, whereas histone deacetylases were primarily involved in regulating AR expression. In contrast, JumonjiC-domain (JmjC) containing histone lysine demethylases (KDMs) mainly had an impact on cell proliferation. Our results show that the KDMs JARID1B, PHF8, KDM3A, KDM3B and KDM4A were highly expressed in clinical PrCa samples. The PHD-finger protein 8 (PHF8), a transcriptional coactivator with both PHD- and JmjC-domains, was moderately to strongly expressed in 80% of clinical PrCa samples, whereas 76% of normal and benign samples were negative or only showed weak PHF8 expression. Strong PHF8 expression correlated significantly with high Gleason grade and was borderline significant for poor prognosis. The results of functional PHF8 knockdown implicate a role in cell migration and invasion, as shown by cell motility and 3-D invasion assays. Our study suggests that various cellular phenotypes are regulated by distinct subsets of epigenetic enzymes. Proteins interpreting and modifying histone methylation, such as JmjC-domain and particularly PHD-finger proteins like PHF8, are activated in subsets of PrCa's and promote cancer relevant phenotypes.

Analysis of interleukin-1beta-modulated mRNA gene transcription in human gingival keratinocytes by epithelia-specific cDNA microarrays.

BACKGROUND/OBJECTIVES: Proinflammatory cytokines such as interleukin-1beta are known to be synthesized in oral gingivitis and periodontitis and lead to the activation of the transcription factor nuclear factor-kappaB (NF-kappaB). Although numerous effects of interleukin-1beta on mesenchymal cells are known, e.g. up-regulation of intercellular adhesion molecule-1 in endothelial cells, little is known of the effects of interleukin-1beta on oral keratinocytes. The purpose of the present study was to seek interleukin-1beta-mediated alterations in mRNA gene transcription and a putative activation of NF-kappaB in oral gingival keratinocytes. METHODS: As an in vitro model for gingivitis and periodontitis, immortalized human gingival keratinocytes (IHGK) were stimulated with the proinflammatory cytokine interleukin-1beta. An epithelia-specific cDNA microarray was used to analyze mRNA expression profiles from IHGK cells treated with 200 units interleukin-1beta/ml for 3, 6, 9, 12, and 24 h. Indirect immunofluorescence was carried out to detect NF-kappaB in IHGK following interleukin-1beta treatment. RESULTS: Detailed analysis revealed distinct patterns of time-dependent changes, including genes induced or repressed early (3-6 h) or late (12-24 h) after interleukin-1beta treatment. Differentially expressed genes were involved in (i) cell stress, (ii) DNA repair, (iii) cell cycle and proliferation, (iv) anti-pathogen response, (v) extracellular matrix turnover, and (vi) angiogenesis. A large number of genes were responsive to NF-kappaB and induction was concomitant with nuclear translocation of the p65 RelA subunit of NF-kappaB. Interestingly, many of these genes contain multiple NF-kappaB binding sites in their promoters. CONCLUSION: Analysis of altered gene expression allows identification of gene networks associated with inflammatory responses. In addition to a number of well-known genes involved in gingivitis and periodontitis, we identified novel candidates that might be associated with the onset and maintenance of an inflammatory disease.

[Osteoporosis in patients under oral anticoagulant treatment]. / Osteoporose bei Patienten unter oraler Antikoagulantien-Therapie.

BACKGROUND AND OBJECTIVE: Osteoporosis is thought to be one possible side-effect of oral anticoagulant therapy, especially after long-term treatment. Nevertheless, data concerning this problem only exist from earlier years. Therefore, we decided to look for the incidence of osteoporosis in patients under long-term oral anticoagulant treatment. PATIENTS AND METHODS: 30 patients (15 female, 15 male) - age between 38 and 77 years (average age 65,1+/-11,2 years) were examined. Group A: 10 patients with a capture time between 0,5 - 5 years, Group B: 10 patients with a capture time between 6 - 11 years, Group C: 10 patients with a capture time more than 11 years. The control group consisted 30 healthy persons - age between 39 and 81 years (18 female, 12 male, average age 61,5 +/- 12 years). RESULTS: In 21 out of 30 patients (9 female, 12 male) osteoporosis was found due to results of x-ray and bone-density-measurements. In 9 patients (6 female, 3 male) no osteoporosis was detected. No correlation between appearance of osteoporosis and duration of oral anticoagulant treatment was detected. Nevertheless, the number of patients presenting with osteoporosis in comparison with the control group was highly unexpected and astonishing. CONCLUSION: While treating patients with oral anticoagulants the possibility of appearing osteoporosis should be kept in view. In those circumstances the therapy should be supported by calcium and vitamin D.

[Significance of aberrant p53 protein in head-neck tumors and its effect on proliferation and differentiation]. / Die Bedeutung von aberrantem p53-Protein in Kopf-Hals-Tumoren und sein Einfluss auf Proliferation und Differenzierung.

Mutation of the tumor suppressor gene p53 is the most frequent genetic alteration of human tumors. Our systematic immunohistochemical analysis of the p53 phenotype and the comparison to proliferation and differentiation has revealed that over 50% of the squamous cell carcinomas of the head and neck show p53 accumulation of aberrant p53 protein. Normal epithelia did not show p53 accumulation and benign lesions only in exceptional cases. Expression of aberrant p53 was invariably confined to dysplastic cells in close vicinity to the tumor and to invasive, dedifferentiated tumor cells with high proliferative potential, as revealed by expression of the histone H3 gene and of the simple epithelial type cytokeratins. We discuss the possible clinical value of the immunohistochemical screening of tumor patients for the status of the p53 gene.

Papillomavirus type 16 oncogenes downregulate expression of interferon-responsive genes and upregulate proliferation-associated and NF-kappaB-responsive genes in cervical keratinocytes.

Infection with high-risk human papillomaviruses (HPV) is a major risk factor for development of cervical cancer. Expression of the HPV E6 and E7 oncoproteins increases in differentiating keratinocytes, resulting in inactivation of the p53 and retinoblastoma proteins, two important transcriptional regulators. We used cDNA microarrays to examine global alterations in gene expression in differentiating cervical keratinocytes after infection with retroviruses encoding HPV type 16 (HPV-16) E6 and E7. Expression of 80 cellular genes (approximately 4% of the genes on the array) was altered reproducibly by E6 and/or E7. Cluster analysis classified these genes into three functional groups: (i) interferon (IFN)-responsive genes, (ii) genes stimulated by NF-kappaB, and (iii) genes regulated in cell cycle progression and DNA synthesis. HPV-16 E6 or a dominant negative p53 protein downregulated multiple IFN-responsive genes. E6 decreased expression of IFN-alpha and -beta, downregulated nuclear STAT-1 protein, and decreased binding of STAT-1 to the IFN-stimulated response element. E7 alone was less effective; however, coexpression of E6 and E7 downregulated IFN-responsive genes more efficiently than E6. The HPV-16 E6 protein also stimulated expression of multiple genes known to be inducible by NF-kappaB and AP-1. E6 enhanced expression of functional components of the NF-kappaB signal pathway, including p50, NIK, and TRAF-interacting protein, and increased binding to NF-kappaB and AP-1 DNA consensus binding sites. Secretion of interleukin-8, RANTES, macrophage inflammatory protein 1alpha, and 10-kappaDa IFN-gamma-inducible protein were increased in differentiating keratinocytes by E6. Thus, high-level expression of the HPV-16 E6 protein in differentiating keratinocytes directly alters expression of genes that influence host resistance to infection and immune function.

Tumor necrosis factor-alpha promotes human papillomavirus (HPV) E6/E7 RNA expression and cyclin-dependent kinase activity in HPV-immortalized keratinocytes by a ras-dependent pathway.

Tumor necrosis factor-alpha (TNF-alpha) inhibits growth of normal cervical keratinocytes but stimulates proliferation of human papillomavirus (HPV)-immortalized and cervical carcinoma-derived cell lines when mitogens such as epidermal growth factor (EGF) or serum are depleted. Current work identifies the mechanism of growth stimulation. TNF-alpha promoted cell cycle progression by increasing expression of HPV-16 E6/E7 RNAs and enhancing activity of cyclin-dependent kinase (cdk)2 and cdc2 after 3 d. Increased kinase activity was mediated by upregulation of cyclins A and B and decreases in cdk inhibitors p21(waf) and p27(kip). TNF-alpha stimulated these changes in part by increasing transcription and stabilization of RNA for amphiregulin, an EGF receptor ligand, and amphiregulin directly increased HPV-16 E6/E7 and cyclin A RNAs. To define which components of the EGF receptor signaling pathway were important, HPV-immortalized cells were transfected with activated or dominant negative mutants of Ha-ras, raf, or MAPKK. Expression of activated Ha-ras maintained HPV-16 and cyclin gene expression and promoted rapid growth in the absence of EGF. Furthermore, ras activation was necessary for TNF-alpha mitogenesis as transfection with a dominant negative ras mutant (Asn-17) strongly inhibited growth. Thus, activation of ras promotes expression of HPV-16 E6/E7 RNAs, induces cyclins A and B, and mediates growth stimulation of immortal keratinocytes by TNF-alpha. These studies define a pathway by which ras mutations, which occur in a subset of cervical cancers, may contribute to pathogenesis. Mol. Carcinog. 27:97-109, 2000. Published by Wiley-Liss, Inc.

Detection of integrated papillomavirus sequences by ligation-mediated PCR (DIPS-PCR) and molecular characterization in cervical cancer cells.

Human papillomavirus (HPV) genomes usually persist as episomal molecules in HPV associated preneoplastic lesions whereas they are frequently integrated into the host cell genome in HPV-related cancers cells. This suggests that malignant conversion of HPV-infected epithelia is linked to recombination of cellular and viral sequences. Due to technical limitations, precise sequence information on viral-cellular junctions were obtained only for few cell lines and primary lesions. In order to facilitate the molecular analysis of genomic HPV integration, we established a ligation-mediated PCR assay for the detection of integrated papillomavirus sequences (DIPS-PCR). DIPS-PCR was initially used to amplify genomic viral-cellular junctions from HPV-associated cervical cancer cell lines (C4-I, C4-II, SW756, and HeLa) and HPV-immortalized keratinocyte lines (HPKIA, HPKII). In addition to junctions already reported in public data bases, various new fusion fragments were identified. Subsequently, 22 different viral-cellular junctions were amplified from 17 cervical carcinomas and 1 vulval intraepithelial neoplasia (VIN III). Sequence analysis of each junction revealed that the viral E1 open reading frame (ORF) was fused to cellular sequences in 20 of 22 (91%) cases. Chromosomal integration loci mapped to chromosomes 1 (2n), 2 (3n), 7 (2n), 8 (3n), 10 (1n), 14 (5n), 16 (1n), 17 (2n), and mitochondrial DNA (1n), suggesting random distribution of chromosomal integration sites. Precise sequence information obtained by DIPS-PCR was further used to monitor the monoclonal origin of 4 cervical cancers, 1 case of recurrent premalignant lesions and 1 lymph node metastasis. Therefore, DIPS-PCR might allow efficient therapy control and prediction of relapse in patients with HPV-associated anogenital cancers.