Alterations of UHRF family Expression and was regulated by High Risk Type HPV16 in Uterine Cervical Cancer.

The altered protein expression of inverted CCAAT box-binding protein of 90 kDa/ubiquitin-like with PHD and RING finger domains 1 (ICBP90/UHRF1), and Np95-like ring finger protein (NIRF)/UHRF2, which belong to the ubiquitin-like with PHD and RING finger domains (UHRF) family, is linked to tumor malignancy and the progression of various cancers. In this study, we analyzed the UHRF family expression in cervical cancers, and it's regulation by human papillomavirus (HPV). Western blotting was performed to analyze protein expression in cervical cancer cell lines. Immunohistochemical analysis were used to investigate the expression of UHRF family and MIB-1 in cervical cancer tissues. Transfection were done for analyze the relationship between UHRF family and HPVs. We showed that NIRF expression was decreased and ICBP90 expression was increased in cervical cancers compared to normal counterparts. Western blotting also showed that NIRF expression was quite low levels, but ICBP90 was high in human cervical cancer cell lines. Interestingly, ICBP90 was up regulated by high risk type HPV16 E6 and E7, but not low-risk type HPV11. On the other hand, NIRF was down regulated by high risk type HPV16 E6 but not by E7. Low risk type HPV11 E6 did not affect the NIRF expression at all. We propose that ICBP90 overexpression, and reduced NIRF expression, found in cervical cancers, is an important event of a cervical carcinogenesis, and especially ICBP90 may offer a proliferating marker and therapeutic target for treating uterine cervical cancers.

Alterations of UHRF Family Expression and UHRF1/ICBP90 Inhibits Phosphatase and Tensin Homolog Expression in Endometrial Cancer.

INTRODUCTION: The altered protein expression of inverted CCAAT box-binding protein of 90 kDa/ubiquitin-like with PHD and RING finger domains 1 (ICBP90/UHRF1) and Np95-like ring finger protein (NIRF)/UHRF2, which belong to the ubiquitin-like with PHD and RING finger domains (UHRF) family, is linked to tumor malignancy and the progression of various cancers. To determine the role of NIRF and ICBP90 in endometrial tumorigenesis, we evaluated ICBP90 and NIRF expression levels in endometrial cancers. Also molecular alterations of phosphatase and tensin homolog (PTEN) expression are the important event for endometrial carcinogenesis; therefore, we investigated the involvement between ICBP90 and PTEN expression. METHODS: We used Western blot for NIRF, ICBP90, and PTEN expression, mutation analysis of NIRF gene, and immunohistochemical staining for the expression of NIRF and ICBP90. For immunohistochemical staining, we examined atypical endometrial hyperplasia, endometrial cancers, and noncancerous samples. RESULTS: Our data showed that the reduced expression of NIRF and overexpression of ICBP90 occurred in atypical endometrial hyperplasia and endometrial cancer compared to the normal endometrium. The decrease in NIRF expression was significantly correlated with histological grade. Expression of ICBP90 was high, especially in the peripheral margin of a cancer nest. Western blot analysis of endometrial cancer cell lines referred an opposite correlation between ICBP90 and PTEN expression. CONCLUSION: Our findings suggested that continually overexpressed ICBP90 may contribute to the inhibition of PTEN expression, which is a frequent and important event in endometrial carcinogenesis. We propose that the reduced NIRF expression and ICBP90 overexpression is an early event in endometrial carcinogenesis; thus ICBP90 may be useful as a therapeutic target in this disease.

Abnormal Expression of PICT-1 and Its Codon 389 Polymorphism Is a Risk Factor for Human Endometrial Cancer.

OBJECTIVE: The protein interacting with carboxyl terminus-1 (PICT-1) gene has been implicated as a tumor suppressor gene, and its alterations have been reported in several cancers. This study investigated the association of PICT-1 alterations with endometrial carcinogenesis. METHODS: We analyzed the entire coding region of the PICT-1 gene using polymerase chain reaction-single-strand conformation polymorphism and DNA sequencing to examine PICT-1 mutations in endometrial cancer. Western blotting and immunohistochemical staining were performed to analyze the protein expression and cellular localization of PICT-1 in endometrial cancer cell lines and patient samples. RESULTS: The codon 389 polymorphism of PICT-1 increased the risk of endometrial cancer. Interestingly, 2 of 13 endometrial cancers somatically acquired this mutation compared to normal counterparts. Immunohistochemical staining revealed lower levels of PICT-1 in samples from atypical endometrial hyperplasia and endometrial cancer tissues compared to normal endometrial tissues (p < 0.01). This decrease in PICT-1 expression was significantly correlated with histological grade and lymph node metastasis (p < 0.05). CONCLUSIONS: The findings of this study suggest that disruption of PICT-1 protein expression and codon 389 polymorphism can contribute to the pathogenesis or neoplastic progression of endometrial cancer.

The expression of 11 beta hydroxysteroid dehydrogenase in severe allergic rhinitis.

OBJECTIVE: To clarify the roles of 11 beta-HSD in resistance to glucocorticoid therapy for allergic rhinitis, a case series study was conducted. METHODS: The patient group consisted of 20 subjects with allergic rhinitis, aged from 21 to 46 years (mean age 26.5), who showed persistent GC resistance necessitating surgical removal of the inferior turbinate after 6 months' GC treatment. The patients with poor response to GC treatment for 6 months' were defined as GC resistance. The control group consisted of 10 subjects aged from 16 to 39 years (mean age 24.5) who underwent maxillofacial surgery, from whom nasal tissues were taken and who did not receive GC treatment. Nasal mucosal tissues from patients and cntorol subjects were examined immunohistochemically. The sections were washed with 0.01 M phosphate-buffered saline (PBS; pH 7.2) containing 0.15 M NaCl and 0.01% Triton X-100, and incubated for 2 h with rabbit polyclonal anti-11 beta HSD1 and 11 beta-HSD2 antibody (Santa Cruz Biotechnology, Inc., Santa Cruz, CA, USA), each diluted 1:200 in PBS containing 0.1% bovine serum albumin. Immunostained sections were assessed under an Olympus microscope with an eyepiece reticule at 200 X magnification. Cell counts are expressed as means per high-power field (0.202 mm2). Control group means (arithmetic mean ± SD) were compared with patient group means by Mann-Whitney U-test at P = 0.05. RESULTS: Although 11 beta-HSD1 was expressed to a similar extent in patients and controls, 11 beta-HSD2 was expressed significantly more in patients with severe allergic rhinitis, resulting in a increased HSD-1/HSD-2 ratio. The significantly increased expression of 11 beta-HSD2 in the nasal epithelium and submucosal inflammatory cells of patients with severe nasal allergy were observed in the present study. CONCLUSION: Our findings suggest that 11 beta-HSD2 plays an important role in resistance to glucocorticoid therapy for allergic rhinitis, and its expression might be used as an additional parameter indicating steroid resistance in allergic rhinitis.

The protein interacting with carboxyl terminus-1 codon 389 polymorphism impairs protein interacting with carboxyl terminus-1 function and is a risk factor for uterine cervical cancer.

PICT-1 is a nucleolar protein with various tumor suppressor functions. Recently, PICT-1 expression was reported to be dramatically reduced in several cancers. To investigate the role of PICT-1 in uterine cervical carcinogenesis, we examined its gene mutations, protein expression, cellular localization, and effect on p53 stabilization. PCR-SSCP analysis of the entire coding region of PICT-1 showed that a polymorphism at codon 389 may increase the risk of uterine cervical cancers, and also identified a novel missense mutation. Expression of wild-type PICT-1 inhibited the degradation of p53 in the presence or absence of HPV 18 E6 viral protein in vitro, while the expression of codon 389 polymorphic PICT-1 had a diminished inhibitory effect on p53 degradation. Moreover, we observed that PICT-1 degradation was induced both independently and cooperatively by E6 and E7 proteins from high-risk HPVs, but only marginal degradation was observed with proteins from low-risk HPV. Immunohistochemical staining of tumor samples revealed that lower levels of PICT-1 were observed in samples from CIN III and cervical cancer tissues, compared to normal cervical epithelium and CIN I, II tissues (P < 0.05). The reduction of PICT-1 may therefore be an early event in uterine cervical tumorigenesis. Our results indicated that PICT-1 counteracts HPV-induced p53 degradation and that aberrant PICT-1 function may contribute towards inactivating p53. Therefore, PICT-1 may play a critical role during the pathogenesis of uterine cervical cancers.

The human papillomavirus18 E7 protein inhibits CENP-C binding to α-satellite DNA.

Human papillomavirus (HPV) infection leads to aneuploidy, a numerical chromosomal aberration that is caused by dysregulation of chromosomal segregation. We previously found that the E7 proteins of high-risk HPVs, but not of low-risk HPVs, could bind to centromere protein-C (CENP-C). In this study, we first found that CENP-C could bind centromere α-satellite DNAs using ChIP analysis and HA-tagged CENP-C/nuc transfected 293T cells. We then investigated if HA-CENP-C/nuc binding to α-satellite DNAs was affected by the E7 proteins of high- or low-risk HPVs. We found that transfection of the FLAG tagged HPV18 E7 inhibited the binding of HA-CENP-C/nuc to α-satellite DNAs. This finding was confirmed in HeLa S3 cells transfected with siRNA targeted to HPV18 E7 expression. We therefore speculate that altered function of kinetochores as a result of inhibition of CENP-C and α-satellite DNAs binding may be associated with the chromosomal abnormalities observed in HPV18-positive cancers.

The PxDLLCxE sequence in conserved region 2 of human papilloma virus 18 protein E7 is required for E7 binding to centromere protein C.

High-risk human papillomaviruses (HPVs) are etiologically linked to human cervical and oral cancers. HPV infection leads to aneuploidy, a numerical chromosomal aberration caused by dysregulation of chromosomal segregation. We found that high-risk HPV18 and HPV58 E7 proteins bind to centromere protein C (CENP-C), a component of the kinetochore that is essential for proper chromosomal segregation. Low-risk HPV4, HPV6, and HPV11 E7s do not bind to CENP-C. The PxDLLCxE sequence in conserved region 2 (CR2) of HPV18 E7 is required for E7 binding to CENP-C. Our results indicate that differences in the ability of high- and low-risk HPV E7s to bind to CENP-C reflect the different oncogenic potentials of high- and low-risk type HPVs.

Characterization of physical binding between human papillomavirus 18 protein E7 and centromere protein C.

Human papillomaviruses (HPVs) have been linked to a variety of human diseases, most notably cancer of the cervix. In the majority of cases, HPV proteins E6 and E7 are continuously expressed and bind a variety of cellular proteins. The precise mechanism of HPV-induced carcinogenesis has not been fully elucidated; therefore, we attempted to identify the cellular proteins that interact with HPV18 E7 to better understand the function of this important protein. Using yeast 2-hybrid screening, we identified centromere protein C (CENP-C) as one of the proteins that interact with HPV18 E7. CENP-C interacted with E7 from HPV18 but not from HPV11. The CR2 domain of HPV18 E7 and the C-terminal region of CENP-C were found to be involved in the binding of these proteins. CENP-C is a component of the inner kinetochore and plays an essential role in proper chromosome segregation, mitotic checkpoint function, and kinetochore assembly. HPV18 E7-CENP-C binding may therefore impair centromere function, in turn causing cancers. We speculate that altered function of CENP-C as a result of interactions with HPV E7 may be associated with chromosomal abnormalities in HPV18-positive cancers.

Low p38 MAPK and JNK activation in cultured hepatocytes of DRH rats; a strain highly resistant to hepatocarcinogenesis.

DRH rats are a hepatocarcinogenesis-resistant strain isolated from hepatocarcinogenesis-sensitive Donryu rats, and the liver of DRH shows less histological damage and fewer/smaller neoplastic hepatic lesions by the treatment with hepatocarcinogens. To investigate the mechanism of the resistance, the properties of hepatocytes of DRH and Donryu were compared. In primary culture, DRH hepatocytes exhibited higher proliferation and less apoptosis than Donryu hepatocytes in the presence of EGF and insulin. However, such difference was not correlated to the degree of DNA damage associated with cell culture or cell cycle checkpoint function. Although the mitogen-activated protein kinases [EGF receptor (EGFR) and extracellular signal regulating kinases (ERK1/2)] were activated to the same degree, the stress-activated protein kinases [p38 mitogen-activated protein kinase (p38) and c-jun N-terminal kinase (JNK)] were activated to a lesser degree in the DRH hepatocytes. Treatment with 2-acetylaminofluorene (2-AAF) in vivo also resulted in less JNK and p38 activation in the DRH livers. Furthermore, apoptosis signal-regulating kinase 1 (ASK1) was inhibited by the lysate from the DRH but not by the Donryu hepatocytes. The low activation of the stress-activated protein kinases may be linked to the resistance to cellular stress, which may underlie the hepatocarcinogenesis-resistance in DRH rats.

Low selection of preneoplastic hepatocytes after treatment with the 2-acetylaminofluorene diet-partial hepatectomy regimen in the liver of hepatocarcinogenesis-resistant DRH strain rats.

In hepatocarcinogenesis-resistant DRH rats, preneoplastic hepatocytic lesions are smaller than those of usual rats during carcinogenesis. When preneoplastic hepatocytes from DRH and Donryu (original strain of DRH) were reciprocally transplanted into the livers of DRH and Donryu treated with 2-acetylaminofluorene (2-AAF) diet/two-thirds hepatectomy (PH), the Donryu cells formed small colonies within the DRH liver, whereas the DRH cells formed large colonies within the Donryu liver. The DRH liver showed less degree of oval cell proliferation after treatment with 2-AAF and PH, and DRH hepatocytes were more resistant to the growth-inhibitory effect of 2-AAF after PH. Furthermore, DRH hepatocytes were generally resistant to cytotoxicity of hepatotoxins. The tissue environment of the DRH liver, therefore, is less effective for selective growth of preneoplastic hepatocytes during the carcinogen treatment, which is probably a major cause of the hepatocarcinogenesis-resistance in DRH rats.

Hypoxia-independent overexpression of hypoxia-inducible factor 1alpha as an early change in mouse hepatocarcinogenesis.

Hypoxia-inducible factor 1 (HIF-1) is involved in tumor progression/metastasis and activated in various cancers. Here we show that HIF-1alpha, which plays a major role in HIF-1 activation, is overexpressed in preneoplastic hepatocytic lesions from a very early stage during hepatocarcinogenesis in mice and man. Transcriptional targets of HIF-1, such as vascular endothelial growth factor, glut-1, c-met, and insulin-like growth factor II (IGF-II), were also overexpressed in mouse lesions. Oxygen tension within the lesions was not different from that of the normal hepatic tissues, indicating that HIF-1alpha expression was independent of hypoxia. On the other hand, Akt, the pathway of which can up-regulate HIF-1alpha expression, was activated in the mouse lesions, whereas HIF-1alpha was markedly down-regulated in the mouse hepatocellular carcinoma (HCC) cell lines after treatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002, indicating that HIF-1alpha expression is dependent on PI3K/Akt signaling. Conversely, HIF-1alpha knockdown by short interfering RNA in the HCC cell line resulted in decreased expression of activated Akt together with the HIF-1 target genes, indicating that Akt activation is reversely dependent on HIF-1 activation. Treating the HCC cells with IGF-II or epidermal growth factor (EGF) up-regulated both phospho-Akt and HIF-1alpha, whereas inhibition of IGF-II or EGF signaling down-regulated them both, suggesting that IGF-II and EGF can, at least in part, mediate the activation of Akt and HIF-1alpha. However, Akt was not activated by IGF-II or EGF in the HIF-1alpha knockdown cells, indicating that expression of the HIF-1 target genes is necessary for the Akt activation. These findings suggest that the reciprocal activation of PI3K/Akt signaling and HIF-1alpha may be important in the progression of hepatocarcinogenesis.

Neoplastic hepatocyte growth associated with cyclin D1 redistribution from the cytoplasm to the nucleus in mouse hepatocarcinogenesis.

Cyclin D1 overexpression is a frequent change in hepatocellular carcinomas (HCCs). Our present study demonstrated that cyclin D1 overexpression with abundant cyclin E, cdk4, cdk2, and p27Kip1 (p27) occurred in neoplastic hepatocytes from the early stage of mouse hepatocarcinogenesis. While cyclin D1 expression was mainly found in the cytoplasm of the tumor cells, it shifted to the nucleus in association with cell proliferation after the animals were subjected to a partial hepatectomy (PH), and then returned once more to the cytoplasm when the cells became quiescent. Inhibition of PI3 kinase (PI3K) by Ly294002 in mouse HCC cells in vitro suppressed the nuclear shift of cyclin D1 as well as cell proliferation, while PI3K activation by PTEN suppression failed to induce nuclear shift of cyclin D1, suggesting that PI3K activation is essential but not sufficient for the cyclin D1 nuclear shift. While MEK-ERK1/2 inhibition by PD98059 and mTOR inhibition by rapamycin affected the cyclin D1 nuclear shift and cell proliferation to a lesser extent, both these inhibitors reduced cyclin D1 levels. Finally, although p27, cdk4 and calmodulin (CaM) were detected in the cyclin D1 immunoprecipitates from both quiescent and proliferating HCC cells, Hsc70 and SSeCKS were detected only in the immunoprecipitate from quiescent cells, and p21Waf1/Cip1 (p21) was detected only in that from proliferating cells, suggesting that the cyclin D1 complex is different in quiescent and proliferating cells. These observations indicate that the nuclear/cytoplasmic localization of cyclin D1 plays an important role in the proliferation/quiescence of neoplastic hepatocytes.

Activated hepatic stellate cells overexpress p75NTR after partial hepatectomy and undergo apoptosis on nerve growth factor stimulation.

BACKGROUND: Expression of neurotrophins (NTs) and their receptors is increased during hepatic regeneration, but their role is not well understood. METHODS: NTs and their receptors were investigated by RT-PCR and immunostaining in regenerating livers after two-thirds hepatectomy (PH) and in hepatocytes and hepatic stellate cells (HSCs) isolated from regenerating livers in mice. Induction of apoptosis after treatment with NGF and the expression of alpha-smooth muscle actin (SMA), interleukin 6 (IL-6) and hepatocyte growth factor (HGF) were also investigated in regenerating HSCs. RESULTS: Nerve growth factor (NGF) and p75 NT receptor (p75NTR) mRNA were elevated after PH, while other NTs and NT receptors showed no remarkable change. NGF was detected in regenerating hepatocytes, but not in normal hepatocytes. Regenerating HSCs expressed increased p75NTR and SMA in vivo and showed an activated phenotype and the high expression of HGF and IL-6 in vitro. Enhanced cell death was seen in HSCs, both from normal and regenerating liver, after treatment with NGF. CONCLUSIONS: Although activated HSCs may produce the factors that regulate liver regeneration, the de novo NGF production by regenerating hepatocytes may induce the death of activated HSCs via p75NTR, leading to termination of hepatic regeneration.

Different growth capacity between infant and adult mouse hepatocytes in vitro correlates to the cyclin D1 level without relation to oxidative DNA damage.

BACKGROUND: Proliferating capacity of hepatocytes is rapidly decreased during growth into maturity, but its exact reason(s) are not well known. METHODS: Hepatocytes isolated from infant (10-14 days old) and adult (10-13 months old) B6C3F1 mice were cultivated in the medium containing epidermal growth factor and insulin. Proliferative capacity, apoptosis, morphological changes, cell cycle proteins and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were compared between the two hepatocyte populations. RESULTS: Although adult hepatocytes rapidly underwent cellular crisis characterized by extended morphology and multiple nuclei without proliferation, infant hepatocytes could proliferate with less crisis. Cyclin D1 was much more abundant in the infant than adult cells, but there was no difference according to the expression of cdk4, cdk2, cyclin E and cdk inhibitors (p16(Ink4) (p16), p21(Cip1/Waf1) (p21) and p27(Kip1) (p27)). 8-OHdG became high soon after cultivation, while it rapidly went down after day 2 both in the infant and adult cells. CONCLUSIONS: The high growth capacity of infant hepatocytes in vitro was dependent on the cyclin D1 level, but there was no relation to 8-OHdG.

Expression of NGF in hepatocellular carcinoma cells with its receptors in non-tumor cell components.

Nerve growth factor (NGF) is suggested to have a role in tumor progression in addition to its role in differentiation and survival of neuronal cells. We investigated expression of NGF and its receptors, TrkA and p75NTR, in hepatocellular carcinomas (HCCs). Although hepatocytes and hepatic stellate cells (HSCs) showed respectively weak and intense NGF immunostaining in the background livers of patients suffering from liver cirrhosis (LC) or chronic hepatitis (CH), intense staining was demonstrated in HCC cells of 33 of 54 (61.1%) tumors. RT-PCR detected NGF mRNA in 7 freshly-isolated HCC samples, and in 2 of 4 cases, in which both background livers and tumors could be analyzed, NGF mRNA was more abundant in the tumors than the background livers. TrkA was detected in the smooth muscle cells of hepatic arteries, but it was negative in tumor cells as well as non-neoplastic hepatocytes. p75NTR and alpha-smooth muscle actin (alphaSMA) was expressed in HSCs in the background liver and fibroblast-like cells in stromal septa, whereas HSCs within the HCC tissues were mostly negative for p75NTR but positive for alphaSMA. This suggests that HSCs in HCC have a different property from those in background livers. Furthermore, the stromal septa contained abundant nerve fibers, which may be related to the increased NGF expression in HCC cells. NGF and its receptors are then thought to have a role in cellular interactions involving HCC cells, HSCs, arterial cells and nerve cells in HCC tissues.

Loss of Igf2 imprinting in monoclonal mouse hepatic tumor cells is not associated with abnormal methylation patterns for the H19, Igf2, and Kvlqt1 differentially methylated regions.

IGFII, the peptide encoded by the Igf2 gene, is a broad spectrum mitogen with important roles in prenatal growth as well as cancer progression. Igf2 is transcribed from the paternally inherited allele, whereas the linked H19 is transcribed from the maternal allele. Igf2 imprinting is thought to be maintained by differentially methylated regions (DMRs) located at multiple sites such as upstream of H19 and Igf2 and within Kvlqt1 loci. Biallelic expression (loss of imprinting (LOI)) of Igf2 is frequently observed in cancers, and a subset of Wilms' and intestinal tumors have been shown to exhibit abnormal methylation at H19DMR associated with loss of maternal H19 expression, but it is not known whether such changes are common in other neoplasms. Because cancers consist of diverse cell populations with and without Igf2 LOI, we established four independent monoclonal cell lines with Igf2 LOI from mouse hepatic tumors. We here demonstrate retention of normal differential methylation at H19, Igf2, or Kvlqt1 DMR by all of the cell lines. Furthermore, H19 was found to be expressed exclusively from the maternal allele, and levels of CTCF, a multifunctional nuclear factor that has an important role in the Igf2 imprinting, were comparable with those in normal hepatic tissues with no mutational changes detected. These data indicate that Igf2 LOI in tumor cells is not necessarily linked to abnormal methylation at H19, Igf2, or Kvlqt1 loci.