Biomedical subjects

William E Grizzle

Publications and source records attributed to William E Grizzle.

At least 19 recordsLinked to original sources

PubMed2007

Discrimination between benign and malignant prostate tissue using chromatin texture analysis in 3-D by confocal laser scanning microscopy.

BACKGROUND: Analysis of chromatin texture may improve both the diagnosis and the assessment of the prognosis of prostate cancer. Confocal laser scanning microscopy (CLSM) allows performing measurements in nuclei reconstructed in 3-D. The aim of this study was to evaluate the clinical usefulness of 3-D texture analysis of prostate tissue. METHODS: Image stacks of eight prostate cancer sections were obtained by CLSM of both benign and malignant areas. Texture feature values were computed for individual nuclei. The discriminative power of the texture features was established by receiver operating characteristic (ROC) analysis and linear discriminant analysis (LDA). RESULTS: Texture features were identified that could discriminate between benign and malignant nuclei. LDA correctly classified 89% of the nuclei of the pooled set of benign and malignant nuclei. CONCLUSIONS: 3-D nuclear texture features allow discrimination of most benign and malignant prostate nuclei. We estimate that the classification rates can be increased by improving the image quality.

Adenocarcinoma↗

PubMed2006

Control of prostate cell growth: BMP antagonizes androgen mitogenic activity with incorporation of MAPK signals in Smad1.

Alterations in the signaling pathways of bone morphogenetic proteins (BMPs) and activation of the ERK/MAP kinase (MAPK) pathway by growth factors have been implicated in the development and progression of prostate cancer. Smad1 acts as a substrate for MAPKs and also performs a central role in transmitting signals from BMPs. We found that BMPs/Smad1 signaling inhibits the growth of androgen-sensitive prostate cancer cells. Upon the incorporation of ERK/MAPK signals at its linker region, Smad1 physically interacts with androgen-activated androgen receptor (AR) and suppresses its functions. BMPs induce the function of Smad1 as an AR transcriptional corepressor. We demonstrated in vivo that Smad1 signaling is low in androgen-regulated growth of prostate cancer, is activated after castration, and also is decreased in hormone-independent tumors. The activation status of ERK/MAPK parallels Smad1 in the progression of prostate cancer; thus, our findings indicate a molecular basis for the integration of signals of MAPK and Smad1 in the progression and androgen regulation of prostate cancer.

Adenocarcinoma↗

PubMed2006

Increased expression of thymidylate synthetase (TS), ubiquitin specific protease 10 (USP10) and survivin is associated with poor survival in glioblastoma multiforme (GBM).

BACKGROUND: The limited success of empirically designed treatment paradigms for patients diagnosed with glioblastoma multiforme (GBM) emphasizes the need for rationally designed treatment strategies based on the molecular profile of tumor samples and their correlation to clinical parameters. METHODS: In the current study, we utilize a novel real-time quantitative low density array (RTQ-LDA) to identify differentially expressed genes in de novo GBM tissues obtained from patients with distinctly different clinical outcomes. Total RNA was isolated from a cohort of 21 GBM specimens obtained from patients with either good (long-term survival (LTS) >36 months post surgery, n = 8) or poor (died of the disease (DOD) <24 months post surgery, n = 13) prognosis. Non-neoplastic brain tissue (n = 5) was obtained from patients who underwent surgery for refractory epilepsy. Demographic data was assessed for correlation with survival using Cox proportional hazards models. Sufficient RNA was available to use RTQ-LDA to quantify the expression of 93 independent genes in 5 LTS, 4 DOD, and 5 non-neoplastic brain samples. The eight differentially expressed genes identified by RTQ-LDA in LTS versus DOD (P <or= 0.050) were subsequently quantified in all 21 GBM samples by real-time quantitative PCR (RTQ). RESULTS: A correlation between younger patients and good prognosis was demonstrated (P <or= 0.05). The combination of RTQ-LDA and RTQ identified thymidylate synthetase (TS), ubiquitin specific protease 10 (USP10), and survivin as significantly over-expressed (P <or= 0.050) in DOD compared to LTS patients. Ribonucleotide reductase subunit M2 (RRM2) was identified as tumor-specific, but not associated with survival. CONCLUSIONS: Taken collectively, TS, USP10, survivin and RRM2 may be useful as prognostic indicators and/or in the development of rationally designed treatment protocols.

Adolescent↗

PubMed2006

Ovarian expression of markers associated with proliferation or apoptosis in women with diminished ovarian reserve.

OBJECTIVE: To determine DNA fragmentation and several molecules associated with apoptosis or proliferation in ovaries of patients with diminished ovarian reserve. DESIGN: Cross-sectional analysis. SETTING: Tertiary institutional hospital. PATIENT(S): Patients with benign uterine pathology who had undergone a hysterectomy and oophorectomy were categorized by the citrate clomiphene challenge test in diminished ovarian reserve or control group. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Apoptosis was determined using TUNEL (terminal deoxynucleotidyl transferase biotin-dUTP nick end-labeling) assay and p53, p27, Bax, caspase-3, caspase-8, caspase-9, Fas-L, Bcl-2, GATA-4, Ki-67, proliferating-cell nuclear antigen (PCNA), estrogen receptor, P receptor, and androgen receptor expression by immunohistochemistry. RESULT(S): Fifteen patients were studied. DNA fragmentation and expression of Bax, caspase-3, caspase-8, caspase-9, Fas-L, Bcl-2, GATA-4, Ki-67, and PCNA were observed in the whole ovary in both groups. In the control group, the expression of caspase-3 and caspase-8 in the ovarian stroma was significantly higher. CONCLUSION(S): DNA fragmentation and the expression of several molecules that participate in ovarian proliferation or apoptosis are present in cycling ovaries, but these markers were not significantly different in patients with diminished ovarian reserve. Thus, the mechanism leading to diminished ovarian reserve does not involve an easily detectable dysregulation in apoptosis or proliferation of ovarian follicles.

Adult↗

PubMed2006

Murine mammary carcinoma exosomes promote tumor growth by suppression of NK cell function.

Many tumor cells shed specialized membrane vesicles known as exosomes. In this study, we show that pretreatment of mice with exosomes produced by TS/A or 4T.1 murine mammary tumor cells resulted in accelerated growth of implanted tumor cells in both syngeneic BALB/c mice and nude mice. As implanted TS/A tumor cells grew more rapidly in mice that had been depleted of NK cells, we analyzed the effects of the tumor-derived exosomes on NK cells. The tumor-derived exosomes inhibit NK cell cytotoxic activity ex vivo and in vitro as demonstrated by chromium release assays. The treatment of mice with TS/A tumor exosomes also led to a reduction in the percentages of NK cells, as determined by FACS analysis, in the lungs and spleens. Key features of NK cell activity were inhibited, including release of perforin but not granzyme B, as well as the expression of cyclin D3 and activation of the Jak3-mediated pathways. Human tumor cell lines also were found to produce exosomes that were capable of inhibiting IL-2-stimulated NK cell proliferation. Exosomes produced by dendritic cells or B cells did not. The presentation of tumor Ags by exosomes is under consideration as a cancer vaccine strategy; however, we found that pretreatment of mice with tumor exosomes blunted the protective effect of syngeneic dendritic cells pulsed ex vivo with tumor exosomes. We propose that tumor exosomes contribute to the growth of tumors by blocking IL-2-mediated activation of NK cells and their cytotoxic response to tumor cells.

Animals↗

PubMed2006

Celecoxib inhibits cellular growth, decreases Ki-67 expression and modifies apoptosis in ovarian cancer cell lines.

BACKGROUND: There is controversy on the safety of inhibitors of cyclooxygenase administered at high doses; however, these drugs have been reported to be effective in the prevention of a variety of human cancers. To determine if celecoxib influences cellular growth, we evaluated several effects in ovarian carcinoma cell lines. METHODS: CAOV3, OVCAR3 and SKOV3 cell lines were exposed to different concentrations of celecoxib (0-100 microM) for 24-96 h. Cellular growth was assessed using a cell viability assay. Immunohistochemistry was performed to evaluate Ki-67 and cleaved caspase-3. Apoptosis was determined by a TUNEL assay, and Western blot was used to determine COX-2 protein expression. RESULTS: We observed a significant decrease in the cellular growth of all cell lines studied exposed to > or = 70 microM of celecoxib for 72 and 96 h (p < 0.02). All cells demonstrated pancytotoxicity at 100 microM of celecoxib. A significant decrease in Ki-67 expression in all cell lines exposed to > or = 30 microM of celecoxib (p < or = 0.05) for 72 h was observed. We observed significant changes in apoptosis and cleaved caspase-3 expression in SKOV3 cells exposed to 50 microM of celecoxib. Downregulation of COX-2 protein expression caused by celecoxib was observed in SKOV3 cells. CONCLUSIONS: We found that celecoxib inhibits cellular growth and proliferation in a dose-dependent manner in all cell lines studied. SKOV3 cells showed an increase in cleaved caspase-3 expression. Additional studies are in progress to evaluate the effects of celecoxib on other aspects of the control of the cell cycle in cancer cells.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2006

Biomarkers in Diagnosis of pancreatic carcinoma in fine-needle aspirates.

This study was undertaken to determine whether recently identified proteins could be translated to clinical practice as markers to distinguish pancreatic adenocarcinoma from chronic pancreatitis on fine-needle aspirate (FNA) samples. Resected pancreatic tissue sections (n = 40) and FNA samples (n = 65) were stained for clusterin-beta, MUC4, survivin, and mesothelin. For each biomarker, the staining patterns in adenocarcinoma and in reactive ductal epithelium were evaluated and compared. Clusterin-beta stained reactive ductal epithelium significantly more frequently than pancreatic adenocarcinoma (P < .001). In comparison, MUC4 and mesothelin were expressed more frequently in pancreatic adenocarcinoma on tissue sections. Positive staining for MUC4 (91% vs 0%; P < .001) and mesothelin (62% vs 0%; P = .01) and absence of staining for clusterin-beta (90% vs 7%; P < .001) were noted significantly more frequently in adenocarcinoma cells than in reactive cells in FNA samples. Clusterin-beta and MUC4 can help distinguish reactive ductal epithelial cells from the cells of pancreatic adenocarcinoma in FNA samples.

Adenocarcinoma↗

PubMed2006

Multiple gene expression analyses in paraffin-embedded tissues by TaqMan low-density array: Application to hedgehog and Wnt pathway analysis in ovarian endometrioid adenocarcinoma.

Recent studies have shown the hedgehog and Wnt families of signaling proteins to be associated with tumor initiation, growth, and survival. However, these pathways remain unexplored in ovarian endometrioid adenocarcinoma (OEA). Here, we describe a novel TaqMan low-density array to examine the expression of 26 and 20 genes in the hedgehog and Wnt pathways, respectively, in six matched snap-frozen and formalin-fixed, paraffin-embedded (FPE) OEA specimens. Expression values were normalized to uninvolved ovarian epithelium. Gene expression in matched frozen and FPE tissues demonstrated significant concordance (r = 0.92, P < 0.0001). However, comparison of amplified and unamplified RNA from frozen OEA tissues revealed an altered molecular profile in amplified RNA. Amplification of RNA from FPE tissues was not successful. The expression of Desert hedgehog (DHH), Indian hedgehog (IHH), Hedge-hog interacting protein (HHIP), Wnt10B, Wnt9B, and Wnt inhibitory factor (WIF1) were tumor-specific with no detectable expression in normal ovarian epithelium. In addition, several genes were significantly (P < 0.025) down-regulated in OEA, including cyclin E2, Porcupine, c-Myc, and Axin 2 (4.8-, 3.6-, 2.9-, and 1.9-fold, respectively). TaqMan low-density array provides an effective multivariate technique for examining gene expression in RNA isolated from either snap-frozen or archival FPE tissues and can identify tumor-specific genes, possibly leading to novel treatments.

Animals↗

PubMed2006

Mucinous expression in benign and neoplastic glandular lesions of the uterine cervix.

CONTEXT: Mucins are glycoproteins produced by both normal and neoplastic glandular epithelial cells including endocervix. OBJECTIVE: To determine the expression of mucins in uterine cervical glandular lesions and whether mucin expression correlates with the nature and origin of the glandular lesions. DESIGN: Antibodies to MUC1, MUC2, MUC4, and MUC5AC were applied on 52 cases including 14 endocervical adenocarcinomas (including 4 adenosquamous carcinomas), 9 endometrial carcinomas (8 endometrioid adenocarcinomas and 1 adenosquamous carcinoma), 8 adenocarcinoma in situ (AIS), 2 glandular dysplasias, 6 tubal metaplasias, 10 microglandular hyperplasias, and 3 normal endocervix. The presence of any staining was considered positive. RESULTS: All benign endocervical epithelia, including tubal metaplasia and microglandular hyperplasia, expressed MUC1, MUC4, and MUC5AC but not MUC2. Almost all endocervical AIS and carcinomas and all endometrial adenocarcinomas expressed MUC1; the exceptions were 2 cases of endocervical adenocarcinoma and 1 case of adenosquamous carcinoma of the endocervix. MUC2 staining was noted in 25%, 40%, and 22% of AIS, endocervical adenocarcinomas, and endometrial adenocarcinomas, respectively. About 38% of AIS, 75% of endocervical adenocarcinomas, and 44% of endometrial adenocarcinomas expressed MUC4. Half of AIS, most of endocervical adenocarcinomas, and 22% of endometrial adenocarcinomas expressed MUC5AC. The difference in MUC4 and MUC5AC expression between benign endocervical lesions and AIS and the difference in MUC5AC expression between endocervical and endometrial neoplasms were statistically significant. CONCLUSIONS: Mucin expressions differed among benign endocervical lesions and AIS and among endocervical and endometrial malignancies. These results suggest that mucin staining may potentially be helpful in differentiating various uterine cervical glandular lesions.

Adenocarcinoma↗

PubMed2006

Oncolytic HSV-1 for the treatment of brain tumours.

The prognosis for patients diagnosed with malignant glioma, the most common primary tumour of the central nervous system, remains poor despite decades of research and advances in surgery, radiation and chemotherapy. The development of new approaches for the treatment of these tumours has led to the emergence of oncolytic viral therapy, with the use of conditionally replicating viruses, as a potential new intervention. Herpes simplex virus type 1 has emerged as the leading candidate oncolytic virus, with six different trials either completed or underway for patients with malignant glioma. In this review, the background of this approach will be discussed, followed by a discussion of the clinical trials, as well as potential directions for future trials.

Brain Neoplasms↗

PubMed2005

Anti-tumor activity of TRA-8 anti-death receptor 5 (DR5) monoclonal antibody in combination with chemotherapy and radiation therapy in a cervical cancer model.

OBJECTIVES: There is substantial evidence that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) causes apoptosis via activation of death receptors 4 and 5 (DR4 and DR5). We sought to determine the therapeutic potential of TRA-8 (anti-DR5 monoclonal antibody) in combination with chemotherapy and radiation therapy in a cervical cancer model. METHODS: DR5 expression in 7 human cervical cancer cell lines was analyzed by indirect immunofluorescence using murine TRA-8 in combination with flow cytometry. Cell lines were treated with TRA-8 alone or in combination with cisplatin, topotecan, or radiation, and cytotoxicity assays were performed. Mice were inoculated with ME-180 cancer cells and treated with different combinations of therapy. Animals receiving antibody were injected intraperitoneally with 200 microg of TRA-8. Animals received 9 Gy 60Co radiation divided into 3 fractions and 3 intraperitoneal doses of cisplatin (6 mg/kg) 1 h before radiation. A similar experiment was performed using topotecan (2 mg/kg) as the chemotherapeutic agent. RESULTS: DR5 was expressed to a varying degree on the cervical cancer cell lines. Combination treatment with TRA-8 and chemotherapy or radiation resulted in synergistic cytotoxicity in vitro. In vivo, combination therapy with TRA-8, cisplatin, and radiation produced tumor growth inhibition that was significantly greater than the other groups. Similar results were seen in combination studies with topotecan. CONCLUSIONS: These data suggest that DR5 is a good target for activation of the apoptotic pathway. Monoclonal antibodies such as TRA-8 may play an important role in the development of an effective treatment strategy for patients with advanced cervical cancer.

Animals↗

PubMed2005

Activation of the neuregulin-1/ErbB signaling pathway promotes the proliferation of neoplastic Schwann cells in human malignant peripheral nerve sheath tumors.

Patients with neurofibromatosis type 1 develop aggressive Schwann cell neoplasms known as malignant peripheral nerve sheath tumors (MPNSTs). Although tumor suppressor gene mutations play an important role in MPNST pathogenesis, it is likely that dysregulated signaling by as yet unidentified growth factors also contributes to the formation of these sarcomas. To test the hypothesis that neuregulin-1 (NRG-1) growth factors promote mitogenesis in MPNSTs, we examined the expression and action of NRG-1 in human MPNSTs and neurofibromas, the benign precursor lesions from which MPNSTs arise. Multiple alpha and beta transmembrane precursors from the class II and III NRG-1 subfamilies are present in both tumor types. Neoplastic Schwann cells within these neoplasms variably express the erbB kinases mediating NRG-1 responses (erbB2, erbB3 and/or erbB4). Human MPNST cell lines (Mash-1, YST-1, NMS-2 and NMS-2PC cells) similarly coexpress multiple NRG-1 isoforms and erbB receptors. These MPNST lines are NRG-1 responsive and demonstrate constitutive erbB phosphorylation. Treatment with PD168393 and PD158780, two structurally and mechanistically distinct erbB inhibitors, abolishes erbB phosphorylation and reduces DNA synthesis in these lines. These findings suggest that autocrine and/or paracrine NRG-1/erbB signaling promotes neoplastic Schwann cell proliferation and may be an important therapeutic target in neurofibromas and MPNSTs.

Biomarkers↗

PubMed2005

High-grade tumor differentiation is an indicator of poor prognosis in African Americans with colonic adenocarcinomas.

BACKGROUND: To identify the factors that contribute to poorer colon carcinoma survival rates for African Americans compared with Caucasians, the authors evaluated survival differences based on the histologic grade (differentiation) of the tumor. METHODS: All 169 African Americans and 229 randomly selected non-Hispanic Caucasians who underwent surgery during 1981-1993 for first primary sporadic colon carcinoma at the University of Alabama at Birmingham or its affiliated Veterans Affairs hospital were included in the current study. None of these patients received presurgery or postsurgery therapies. Recently, the authors reported an increased risk of colon carcinoma death for African Americans in this patient population, after adjustment for stage and other clinicodemographic features. The authors generated Kaplan-Meier survival probabilities according to race and tumor differentiation and multivariate Cox proportional hazards models to estimate hazard ratios (HR) with 95% confidence intervals (95% CI). RESULTS: There were no differences in the distribution of pathologic tumor stage between racial groups after stratifying by histologic tumor grade. Among patients with high-grade tumors, 54% of African Americans and 21% of Caucasians died within the first year after surgery (P = 0.007). African Americans with high-grade tumors were 3 times (HR = 3.05; 95% CI, 1.32-7.05) more likely to die of colon carcinoma within 5 years postsurgery, compared with Caucasians with high-grade tumors. There were no survival differences by race among patients with low-grade tumors. CONCLUSIONS: These findings suggested that poorer survival among African-American patients with adenocarcinomas of the colon may not be attributable to an advanced pathologic stage of disease at diagnosis, but instead may be due to aggressive biologic features like high tumor grades.

Adenocarcinoma↗

PubMed2005

Smad4 inhibits tumor growth by inducing apoptosis in estrogen receptor-alpha-positive breast cancer cells.

Estrogen is a mitogen in most estrogen receptor-alpha (ERalpha)-positive breast cancers. We have found that Smad4, a common signal transducer in the transforming growth factor-beta superfamily, acts as an ERalpha transcriptional corepressor. Here, we show that Smad4 induces apoptosis in ERalpha-positive MCF-7 breast cancer cells, but not in ERalpha-negative MDA-MB-231 cells. Smad4 induced expression of short Bim isoforms (by alternative splicing) and Bax and release of cytochrome c in ERalpha-positive cells only, and expression of these apoptotic marker genes was reduced when ERalpha small interfering RNA was introduced. Notably, Smad4 was able to induce apoptosis in MDA-231 cells with acquired ERalpha expression. Furthermore, Smad4 inhibited ERalpha-positive tumor growth by inducing apoptosis in tumor xenografts in nude mice. The sizes of tumors expressing Smad4 were only one-tenth the size of those expressing green fluorescent protein, whereas in ERalpha-negative cells, Smad4 did not reduce the tumor size. Notably, Smad4 also promoted short Bim isoform and Bax expression and release of cytochrome c only in ERalpha-positive MCF-7 tumor xenografts. Bim was sufficient for induction of apoptosis, and the short form was the most potent inducer. Our results demonstrate that Smad4 induces apoptosis by regulating Bim splicing as an initial intrinsic signal in ERalpha-positive cells. Smad4-induced apoptosis in ERalpha-positive breast cancer cells may explain the invasive nature of ERalpha-negative breast tumors, thereby providing a potential target for breast cancer intervention.

Alternative Splicing↗

PubMed2005

Serum levels of an isoform of apolipoprotein A-II as a potential marker for prostate cancer.

PURPOSE: We recently showed that protein expression profiling of serum using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) has potential as a diagnostic approach for detection of prostate cancer. As a parallel effort, we have been pursuing the identification of the protein(s) comprising the individual discriminatory "peaks" and evaluating their utility as potential biomarkers for prostate disease. EXPERIMENTAL DESIGN: We employed liquid chromatography, gel electrophoresis and tandem mass spectroscopy to isolate and identify a protein that correlates with observed SELDI-TOF MS mass/charge (m/z) values. Immunodepletion, immunoassay, and Western analysis were used to verify that the identified protein generated the observed SELDI peak. Subsequent immunohistochemistry was used to examine the expression of the proteins in prostate tumors. RESULTS: An 8,946 m/z SELDI-TOF MS peak was found to retain discriminatory value in each of two separate data sets with an increased expression in the diseased state. Sequence identification by liquid chromatography-MS/MS and subsequent immunoassays verified that an isoform of apolipoprotein A-II (ApoA-II) is the observed 8,946 m/z SELDI peak. Immunohistochemistry revealed that ApoA-II is overexpressed in prostate tumors. SELDI-based immunoassay revealed that an 8.9-kDa isoform of ApoA-II is specifically overexpressed in serum from individuals with prostate cancer. ApoA-II was also overexpressed in the serum of individuals with prostate cancer who have normal prostate-specific antigen (0-4.0 ng/mL). CONCLUSIONS: We have identified an isoform of ApoA-II giving rise to an 8.9K m/z SELDI "peak" that is specifically overexpressed in prostate disease. The ability of ApoA-II to detect disease in patients with normal prostate-specific antigen suggests potential utility of the marker in identifying indolent disease.

Apolipoprotein A-II↗

PubMed2005

Effects of HIV-1 Nef, a cytotoxic viral protein, on the growth of primary colorectal cancer.

Colorectal cancer is the third leading cause of cancer deaths in American men and women. We describe the cytotoxic use of HIV-1 Nef protein and a cytotoxic peptide identified within the HIV-1 Nef structure in targeting human cancer cells in vitro and in vivo in a human xenograft model. A human colorectal tumor was implanted and propagated in the subcutaneous tissue of SCID mice. The mice were injected biweekly with the Nef apoptotic peptide. The tumor treated with Nef peptide underwent significant growth inhibition by as much as 300 percent when compared to the control (untreated) tumors. The Nef peptides were found to have an apoptotic effect on the human colon tumor similar to the effect seen on CD4 cells when the viral protein is secreted by the HIV-1 virus infected cells. The evidence from the xenograft mouse model suggests that the Nef peptides can be used to inhibit human colorectal cancer growth.

Animals↗

PubMed2005

Pattern of nonspecific (or global) DNA methylation in oral carcinogenesis.

BACKGROUND: Although alterations in nonspecific (or global) DNA methylation (GDM) in specific cells are known to be involved in the process of lung carcinogenesis, similar associations have not been evaluated in other smoking-related cancers of the head and neck. METHODS: We evaluated the status of GDM by using monoclonal antibodies specific for 5-methylcytosine (5-mc) in oral squamous cell carcinoma (SCC) specimens of 48 cigarette smokers who had SCC develop and in 93 age-, race-, and sex-matched smokers who did not. RESULTS: Percentages of cells positive for 5-mc immunostaining of DNA of SCC and dysplastic lesions were significantly higher than those of normal oral epithelial cells from cancer subjects and from noncancer subjects. The degree of DNA methylation was unrelated to DNA content. CONCLUSIONS: The pattern of GDM in oral SCCs is different from that of lung SCCs. The differences in nutrient risk factor profiles that are related to GDM and differential activity of DNA methyltranferases between oral and lung SCCs may explain these observations.

5-Methylcytosine↗

PubMed2005

Cholangiocyte endothelin 1 and transforming growth factor beta1 production in rat experimental hepatopulmonary syndrome.

BACKGROUND & AIMS: Hepatic production and release of endothelin 1 plays a central role in experimental hepatopulmonary syndrome after common bile duct ligation by stimulating pulmonary endothelial nitric oxide production. In thioacetamide-induced nonbiliary cirrhosis, hepatic endothelin 1 production and release do not occur, and hepatopulmonary syndrome does not develop. However, the source and regulation of hepatic endothelin 1 after common bile duct ligation are not fully characterized. We evaluated the sources of hepatic endothelin 1 production after common bile duct ligation in relation to thioacetamide cirrhosis and assessed whether transforming growth factor beta1 regulates endothelin 1 production. METHODS: Hepatopulmonary syndrome and hepatic and plasma endothelin 1 levels were evaluated after common bile duct ligation or thioacetamide administration. Cellular sources of endothelin 1 were assessed by immunohistochemistry and laser capture microdissection of cholangiocytes. Transforming growth factor beta1 expression and signaling were assessed by using immunohistochemistry and Western blotting and by evaluating normal rat cholangiocytes. RESULTS: Hepatic and plasma endothelin 1 levels increased and hepatopulmonary syndrome developed only after common bile duct ligation. Hepatic endothelin 1 and transforming growth factor beta1 levels increased over a similar time frame, and cholangiocytes were a major source of each peptide. Transforming growth factor beta1 signaling in cholangiocytes in vivo was evident by increased phosphorylation and nuclear localization of Smad2, and hepatic endothelin 1 levels correlated directly with liver transforming growth factor beta1 and phosphorylated Smad2 levels. Transforming growth factor beta1 also stimulated endothelin 1 promoter activity, expression, and production in normal rat cholangiocytes. CONCLUSIONS: Cholangiocytes are a major source of hepatic endothelin 1 production during the development of hepatopulmonary syndrome after common bile duct ligation, but not in thioacetamide-induced cirrhosis. Transforming growth factor beta1 stimulates cholangiocyte endothelin 1 expression and production. Cholangiocyte-derived endothelin 1 may be an important endocrine mediator of experimental hepatopulmonary syndrome.

Animals↗