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Biomedical subjects

G L Clayman

Publications and source records attributed to G L Clayman.

At least 19 recordsLinked to original sources
PubMed2006

Human LBP-32/MGR is a repressor of the P450scc in human choriocarcinoma cell line JEG-3.

Steroid hormones regulate a wide range of physiologic functions in humans. The cholesterol side-chain cleavage enzyme P450scc regulates the initial step of biosynthesis of all steroid hormones. We investigated the expression of P450scc by studying a potential regulator of P450scc, LBP-32/MGR. Using a Northern blot, we found that LBP-32/MGR mRNA was expressed mainly in the human placenta. Using radiation hybrid mapping, we identified LBP-32/MGR on human chromosome 2p25. Recombinant LBP-32/MGR protein bound preferentially to a DNA fragment from the promoter of P450scc in vitro and exhibited clear nuclear localization in transfected cells. Luciferase reporter gene assays showed that LBP-32/MGR specifically repressed transcriptional activation of the human P450scc promoter. Because placental P450scc expression is essential for pregnancy and steroid biosynthesis, the placental expression and transcriptional repressor activity of LBP-32/MGR in JEG-3 cells suggest it has a role as a transcriptional modulator of steroid biosynthesis.

Cell Line, Transformed↗
PubMed2001

Expression of protease-activated receptor 1 in oral squamous cell carcinoma.

Protease-activated receptor 1 (PAR-1) is a G-coupled membrane protein. In this study, we analyzed the expression of PAR-1 in oral squamous cell carcinomas (SCCs). PAR-1 was expressed in oral SCCs, but the level of PAR-1 protein was lower in non-metastatic cells than in metastatic cells. Thrombin stimulated the growth of metastatic cells, and both thrombin and thrombin receptor activation peptide (TRP) enhanced the adhesion of these cells to fibronectin, but had no effect on non-metastatic cells. Thrombin and TRP also induced matrix metalloproteinase (MMP)-2 and MMP-9 activities in metastatic cells. These results suggest that PAR-1 may contribute to the growth and invasive potential of oral SCC.

Blotting, Western↗
PubMed2001

Chemokines in cancer.

Chemokines are small, chemotactic cytokines that direct migration of leukocytes, activate inflammatory responses and participate in many other pleiotropic functions, including regulation of tumour growth. Chemokines modulate tumour behaviour by three important mechanisms: regulation of tumour-associated angiogenesis, activation of a host tumour-specific immunological response, and direct stimulation of tumour cell proliferation in an autocrine fashion. All of these mechanisms are promising points of cancer intervention, and preclinical mouse models suggest that chemokine antagonists and agonists could become important in the development of new anticancer therapies.

Journal Article↗
PubMed2001

SCCA1 expression in T-lymphocytes peripheral to cancer cells is associated with the elevation of serum SCC antigen in squamous cell carcinoma of the tongue.

Squamous cell carcinoma (SCC) antigen has been used for the management of SCC arising in various cites including head and neck region. However, the true mechanism of the elevation of this protein in the serum of patients with SCC is still unknown. SCC antigen belongs to the superfamily of serine protease inhibitors. Recently, molecular studies show that serum SCC antigen is transcribed by two nearly identical genes (SCCA1 and SCCA2), and is mainly produced by SCCA1. The objective of this study is to clarify the mechanism of the elevation of SCC antigen in oral tongue SCC patients and to identify cells histologically, which are responsible for serum SCC antigen production. In this study, we examined SCCA1 expression in a series of four head and neck SCC (HNSCC) cell lines, and found that all expressed equal to low SCCA1 protein as compared with the normal human oral keratinocyte. Using the double immunohistochemical technique to examine the expression pattern of SCCA1 in 86 cases of oral tongue squamous cell carcinoma, SCCA1 immunostaining was observed in the cytoplasm of cancer cells and T-lymphocytes peripheral to cancer cells. We also compared the clinicopathological features including serum SCC antigen level of the oral tongue SCC cases with the immunohistochemical SCCA1 expression pattern, and found that elevated serum SCC antigen level was significantly correlated with SCCA1 expression not in cancer cells, but in T-lymphocytes peripheral to cancer cells. These results suggest that T-lymphocytes peripheral to cancer cells may be responsible for serum SCC antigen production in HNSCC patients.

Adult↗
PubMed2001

The role of neck dissection after chemoradiotherapy for oropharyngeal cancer with advanced nodal disease.

OBJECTIVE: To analyze and compare the effectiveness of sequential platinum-based chemotherapy and radiotherapy with and without selective neck dissection in patients with N2a and greater stage node-positive squamous cell carcinoma of the oropharynx. DESIGN: Nonrandomized controlled trial. SETTING: Tertiary referral center. PATIENTS: Sixty-six patients with squamous cell carcinoma of the oropharynx staged N2a or greater. INTERVENTIONS: Platinum-based induction chemotherapy followed by definitive radiation therapy; and selective neck dissections 6 to 10 weeks following the completion of radiation therapy in patients with radiographic evidence suggesting residual neck disease. MAIN OUTCOME MEASURES: Locoregional recurrence and disease-free survival. RESULTS: Of 66 patients, 24 (36%) had complete responses in the primary local tumor (oropharynx) and regional disease (neck nodes), as assessed clinically and radiographically. These patients had lower rates of locoregional recurrence than did patients showing no or partial responses, but the differences were not significant (P>.05). Of 18 patients undergoing neck dissection, 10 (56%) had pathological evidence of residual tumor. Patients showing a complete response of regional and neck disease had significantly improved disease-specific and overall survival (P = .01 for both) compared with patients showing no or partial responses of their neck disease. Patients with no or partial responses who underwent neck dissections had significantly improved overall survival compared with similar patients who did not undergo neck dissections (P = .002). CONCLUSIONS: Even in patients with bulky nodal disease, a complete response in the neck to sequential chemotherapy and radiotherapy may indicate that neck surgery is not necessary for good locoregional control and improved disease-free survival. Neck dissection is recommended for patients with no or partial radiographic responses.

Adult↗
PubMed2001

Evidence that the death receptor DR4 is a DNA damage-inducible, p53-regulated gene.

DR4 (TRAIL-R1), a member of the tumor necrosis factor receptor superfamily, is a cell surface receptor that triggers the apoptotic machinery upon binding to its ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Although three other TRAIL receptors DR5, DcR1, and DcR2 are induced by DNA damage and are regulated by the wild-type p53 tumor suppressor, it was not known whether these factors also affect DR4 expression. In this study, we found that DR4 expression is also enhanced by DNA damage whether induced by ionizing radiation or by chemotherapeutic agents. The induction was observed predominantly in cells containing wild-type p53 and was similar to the regulation patterns of DR5 and Fas, two other members of the family which are known to be regulated by p53. Transfection of HPV 16 E6 gene into cells with wild-type p53, which decreased the level of p53 protein, resulted in suppression of DR4 induction by DNA-damaging agents. Conversely, introduction of exogenous wild-type p53 through adenovirus infection has led to upregulation of endogenous DR4 in cells with mutant p53. Moreover, the transcription inhibitor actinomycin D abolished DNA-damaging agent-induced DR4 expression. Thus, DR4 appears to be a DNA damage-inducible, p53-regulated gene.

Adenoviridae↗
PubMed2001

Genetic heterogeneity in saliva from patients with oral squamous carcinomas: implications in molecular diagnosis and screening.

We performed microsatellite analysis at chromosomal regions frequently altered in head and neck squamous carcinoma on matched saliva and tumor samples from 37 patients who had oral squamous carcinoma. The results were correlated with the cytologic findings and traditional clinicopathologic factors to assess the diagnostic and biological potential of these markers. Our data showed that 18 (49%) of the saliva samples and 32 (86%) of the tumors had loss of heterozygosity (LOH) in at least one of the 25 markers studied. In saliva, the combination of markers D3S1234, D9S156, and D17S799 identified 13 (72.2%) of the 18 patients with LOH in saliva (P < 0.001). For tumors, markers D3S1234, D8S254, and D9S171 together identified 27 (84.3%) of the 32 tumors with LOH at any of the loci tested (P < 0.001). Eleven (55%) of the 20 saliva samples with cytologic atypia and seven (35%) of the 17 specimens without atypia had LOH. Significant correlation between LOH in tumor at certain markers and smoking and alcohol use was found. Our results indicate that: 1) epithelial cells in saliva from patients with head and neck squamous tumorigenesis provide suitable material for genetic analysis; 2) combined application of certain markers improves the detection of genetic alteration in these patients; 3) clonal heterogeneity between saliva and matching tumor supports genetic instability of the mucosal field in some of these patients; and 4) LOH at certain chromosomal loci appears to be associated with smoking and alcohol consumption.

Alcohol Drinking↗
PubMed2001

p73 gene alterations and expression in primary oral and laryngeal squamous carcinomas.

p73, a recently identified gene, maps to chromosome region 1p36.3, which is frequently deleted in a variety of solid tumors. Although the gene shares sequence and functional homologies with p53, its suppressor function has not been proven. We investigated for the first time the genetic and expression status of the p73 gene and analyzed its flanking microsatellite loci on chromosome 1p36.3 in 67 primary oral and laryngeal squamous cell carcinomas to determine their association with these tumors. Our results reveal two missense mutations at codons 469 and 477 and a silent mutation at codon 349 in the C-terminal domain. Site-directed mutagenesis of p73 cDNA with these mutations and a p21 transactivation assay failed to show any significant functional consequences of these mutations. Microsatellite analysis of the flanking loci of p73 in region 1p36 showed overall alterations (loss of heterozygosity and instability) frequency of 39%, 16% at the proximal marker and 46% at the distal markers. Of the 21 cases for which we did protein expression analyses, 11 tumors had a >2-fold variation compared with matching histologically normal mucosa. Our study shows that: (i) intragenic alterations in this gene are rare and lack functional significance; (ii) its variable expression argues against a tumor suppressor function; (iii) this gene plays a minor role in head and neck squamous carcinoma; (iv) a distal site to this gene on 1p36 may harbor another suppressor gene.

Adult↗
PubMed2001

All-trans-retinoic acid enhances the effect of adenovirus-mediated wild-type p53 gene transfer in head and neck squamous cell carcinoma.

OBJECTIVES: Adenovirus-mediated p53 (AdCMVp53) gene therapy for cancer is currently undergoing phase III clinical trials. One problematic aspect of this therapy is that the current protocols result in low transduction of the therapeutic virus in vivo. To search new modalities that can enhance the effect of AdCMVp53 gene therapy, we focused on retinoids. METHODS: To study the effect of ATRA in combination with AdCMVp53 gene therapy, we pretreated head and neck squamous cell carcinoma (HNSCC) cells for 72 hours with a low-dose All-trans-retinoic acid (ATRA) (10-7 M-10-8 M) which will not affect the in vitro cell growth, and then infected the cells with low MOI (30MOI) AdCMVp53. In vitro cell proliferation assays, cell cycle assays were performed. Expression of p53 and p53-related gene products, BAX and p21, were examined. RESULTS: The combined treatment with ATRA and Ad-p53 suppressed cell growth and induced apoptosis significantly more than AdCMVp53 treatment alone (P <.05). p53 expression significantly increased more after the combined treatment than after either treatment alone, at both the transcription and protein levels. In addition, increased expression of p21 and BAX, which are downstream gene products of p53, was observed in the combination. ATRA also enhanced the expression of green fluorescent protein (GFP) transduced by an adenovirus-cytomegalovirus (CMV)-GFP vector suggesting ATRA enhances adenovirus-CMV-promoted vectors through transcription. CONCLUSIONS: Our results indicate that ATRA enhances AdCMVp53 expression through transcriptional mechanisms and can synergistically induce apoptosis in HNSCC cells. ATRA has a potential to enhance the effect of adenovirus-mediated p53 gene therapy for HNSCC.

Adenoviridae↗
PubMed2000

Isolation of a peptide for targeted drug delivery into human head and neck solid tumors.

Lack of tumor specificity remains a major problem with chemotherapies in that side effects prevent the delivery of dosages of drugs that are required to eliminate tumors. In this report, we describe the isolation of a 12-mer peptide (HN-1), with approximately 1% of the mass of typical antibodies, that meets several criteria for targeted drug delivery into a solid tumor. First, internalization of HN-1 by human head and neck squamous cell cancer (HNSCC) cells suggests that HN-1 is capable of translocating drugs across cell membranes. Second, HN-1 appears to be HNSCC-specific, given its reduced uptake by nonmalignant human oral keratinocytes and other types of human cells, its preferential binding to primary HNSCC, and its localization to HNSCC-derived xenografts. Third, the presence of HN-1 within HNSCC xenografts suggests that it is capable of penetrating tumor tissues. Our results establish the utility of tumor-specific peptides for targeted drug delivery into solid tumors.

Amino Acid Sequence↗
PubMed2000

Genomic cloning, mapping, structure and promoter analysis of HEADPIN, a serpin which is down-regulated in head and neck cancer cells.

Headpin is a novel serine proteinase inhibitor (serpin) that is down-regulated in squamous cell carcinoma of the oral cavity and in squamous cell carcinoma cell lines of the head and neck. Using a panel of 18q21.3 YAC clones, we mapped and cloned the HEADPIN gene. The gene spans 10 kb and is composed of eight exons and seven introns. The genomic structure is identical with some other ovalbumin serpins (ov-serpins) in terms of the numbers, position and phasing of the intron/exon boundaries. HEADPIN was mapped within the serpin cluster in 18q21.3 between MASPIN and SCCA2 as follows: cen-MASPIN-HEADPIN-SCCA2-SCCA1-tel. The transcription start site was determined and the promoter activity of the 5'-flanking region was analyzed. Luciferase promoter assays in HaCaT cells showed that the -432 to -144 nucleotide region has functional promoter activity. The activity of the promoter/enhancer was not observed in head and neck cancer cell lines TU167 and UMSCC1 which lack headpin expression. These data suggest that the differential expression of headpin in normal and carcinoma-derived cells is regulated at the transcriptional level. Understanding the genomic organization and transcriptional regulation of the ov-serpins clustered within 18q21. 3 provides a critical framework for assessing their potential role in cancer.

Base Sequence↗
PubMed2000

Antisense inhibition of cyclin D1 in human head and neck squamous cell carcinoma.

OBJECTIVE: To study the role of cyclin D1 in regulating the biological behavior of head and neck cancer. DESIGN: Squamous cell carcinoma of the head and neck (SCCHN) cells were stably transfected with an antisense cyclin D1 using lipofectin-mediated transfection. In vitro growth assays, cell cycle analyses, cytotoxicity assays, and in vivo tumorigenicity assays were performed. MATERIALS: Human SCCHN cell lines TU138, TU167, TU177, TU182, MDA183, and MDA1386 and athymic nude mice were used for this study. RESULTS: The antisense cyclin D1 transfected cells revealed decreased growth rates in vitro and decreased tumorigenicity in athymic nude mice. Furthermore, antisense cyclin D1 transfection enhanced the chemosensitivity against cisplatin. CONCLUSIONS: These studies provided evidence that overexpression of cyclin D1 may play an important role in growth rates and biological behavior of human head and neck cancer. Additionally, expression of cyclin D1 may make human head and neck cancer cells resistant to platinum-based chemotherapeutic approaches. The ability to suppress the malignant phenotype by down-regulating cyclin D1 expression may provide a new gene therapy approach for patients with head and neck cancer.

Animals↗
PubMed2000

Telomerase activity in head and neck tumors after introduction of wild-type p53, p21, p16, and E2F-1 genes by means of recombinant adenovirus.

BACKGROUND: Telomerase (reverse transcriptase) has been shown to play a role in the process of cellular immortalization. METHODS: Telomerase activity was determined in 11 head and neck squamous cell carcinoma (SCCHN) cell lines. The effects of wild-type p16, p21, E2F-1, and p53 genes on telomerase activity were examined by introducing the wild-type genes into two SCCHN cell lines by means of a recombinant adenovirus. RESULTS: We found elevated telomerase activity in 10 of the 11 SCCHN cell lines tested. When we infected Tu-138 and Tu-167 cell lines with wild-type p16, p21, E2F-1, and p53 genes, we found that p16 had little effect on telomerase activity. Both E2F-1 and p53 were known to induce apoptosis in SCCHN cell lines. Significantly reduced telomerase activity by p53 in both cell lines and E2F-1 in Tu-167 cells was in agreement with suppression of cell growth. Overexpression of p21 also exhibited reduction in telomerase activity. CONCLUSIONS: We conclude from this study that overexpression of E2F-1 and p53 can reverse telomerase activity in SCCHN cell lines and that telomerase activity may be involved in cancer cell immortalization.

Adenoviridae↗
PubMed2000

Antisense inhibition of vascular endothelial growth factor in human head and neck squamous cell carcinoma.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent paracrine angiogenic factor involved in angiogenesis. We determined whether antisense VEGF transfection can suppress angiogenic activity of a human squamous cell carcinoma of the head and neck (SCCHN) cell line. METHODS: Human SCCHN cell lines were screened for VEGF secretion by ELISA. The highest VEGF secreting cell line was transfected with an antisense VEGF vector. Endothelial cell migration assays were performed using the conditioned medium from the transfected clones. Tumorigenicity assays of the transfectants in nude mice were also performed. RESULTS: Antisense VEGF expression exhibited a 20-fold inhibition of VEGF secretion. The addition of conditioned medium from the antisense clones resulted in 50% reduction of endothelial migration. There was no effect on in vivo tumorigenicity. CONCLUSIONS: Antisense VEGF transfection effectively down-regulated VEGF secretion from SCCHN cells that had high VEGF secretion. Targeting VEGF expression may be useful for suppressing angiogenesis in head and neck cancer.

Angiogenesis Inducing Agents↗
PubMed2000

In vivo expression of the novel CXC chemokine BRAK in normal and cancerous human tissue.

Using differential display, we cloned a gene with reduced expression in short-term explants of head and neck squamous cell carcinoma (HNSCC) tumors compared to cultured normal oral epithelial cells. The differentially expressed gene was identical to the recently cloned CXC chemokine BRAK, which is ubiquitously expressed in normal tissue extracts but is absent from many tumor cell lines in vitro. To define the cell populations expressing BRAK in vivo, in situ mRNA hybridization was performed on normal and cancerous tissues from six different histological sites. The predominant normal cell type constitutively expressing BRAK in vivo was squamous epithelium. Expression in tumors was heterogeneous, with the majority of HNSCCs and some cervical squamous cell carcinomas (SCCs) showing loss of BRAK mRNA. Although absent in unstimulated peripheral blood mononuclear cells, high levels of BRAK were consistently found in infiltrating inflammatory cells (with lymphocyte morphology) in nearly all cancers examined. Furthermore, BRAK expression was demonstrated in B cells and monocytes, after stimulation of peripheral blood mononuclear cells with lipopolysaccharide. This study demonstrates for the first time up-regulation of BRAK mRNA by inflammatory cells in the tumor microenvironment and lost expression from certain cancers in vivo. The data suggest that BRAK may have a role in host-tumor interactions.

Amino Acid Sequence↗
PubMed2000

Primary malignant tumors of the sphenoidal sinus.

OBJECTIVE: Neoplasms of the paranasal sinuses account for 0.2 to 0.8% of all cancers and for 2 to 3% of head and neck cancers. Primary involvement of the sphenoidal sinus has been reported to occur in only 1 to 2% of all paranasal sinus tumors. Tumors at this site commonly present with cranial neuropathies and require multidisciplinary treatment. METHODS: During a 21-year period, 27 patients with primary sphenoidal sinus tumors were evaluated. Those with pituitary tumors and fibro-osseous lesions (fibrous dysplasia) were excluded. The records of all remaining patients were reviewed for the following parameters: age, sex, and ethnic origin; presenting symptoms and signs; radiological features and sites of tumor extension; pathological findings; prior treatments; surgical approaches and extent of resection; adjuvant therapy; complications; and patient outcome. RESULTS: A malignant pathological process was found in 26 of the 27 patients. The most common diseases were squamous cell carcinoma (n = 9), adenoid cystic carcinoma (n = 4), chondrosarcoma (n = 3), and neuroendocrine carcinoma (n = 3). Treatments included surgery (n = 1), surgery and radiotherapy (n = 6), surgery and chemotherapy (n = 3), surgery, radiotherapy, and chemotherapy (n = 4), chemotherapy (n = 5), chemotherapy and radiotherapy (n = 3), and radiotherapy (n = 2). The mean follow-up period from initial evaluation was 41 months (range, 2-199 mo). At the last follow-up, 12 patients (48%) were still alive and 13 (52%) had died. The 2-year survival rate for patients with squamous cell carcinoma was 44%. CONCLUSION: Headache and visual disturbances are common symptoms of sphenoidal sinus tumors. The presence of cranial neuropathies, although common, suggests a less successful outcome. It is advantageous if the surgical team has had experience with both open and endoscopic approaches to the sphenoidal sinus. Patient outcome is maximized by the use of aggressive multidisciplinary therapy.

Adolescent↗