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G L Clayman

Publications and source records attributed to G L Clayman.

At least 55 records · Page 3Linked to original sources
PubMed1998

In vitro growth suppression by adenoviral transduction of p21 and p16 in squamous cell carcinoma of the head and neck: a research model for combination gene therapy.

OBJECTIVES: To determine the duration of expression of the cell cycle regulators p21 and p16 and the effect of these 2 genes both alone and in combination on the growth of squamous cell carcinoma of the head and neck cell lines in vitro. EXPERIMENTAL METHODS AND DESIGN: Cells were transduced via an adenoviral vector with p21 (Ad5CMV-p21), p16 (Ad5CMV-p16), or both. Western blotting was performed to determine duration of expression of the protein products of the transduced p21 and p16 genes. In vitro growth assays and cell cycle analyses were performed on transduced cells. RESULTS: Transduced gene products were detected up to day 12 after infection. Western blotting showed high levels of p21 and p16 in transduced cells. Growth suppression was observed in squamous cell carcinoma of the head and neck cell lines transduced with Ad5CMV-p21, Ad5CMV-p16, or both, but the combination of p21 and p16 did not achieve significantly greater growth suppression than that seen in cells transduced with Ad5CMV-p16 alone. Cell cycle analysis demonstrated that the percentage of cells arrested at G1 stage in the cells transduced with Ad5CMV-p16 was similar to that in the cells transduced with both Ad5CMV-p21 and Ad5CMV-p16. No significant in vivo growth suppression was observed in tumor nodules treated with Ad5CMV-p16. CONCLUSIONS: Although p21 and p16 are believed to function as cell cycle regulators of cyclin-dependent kinases, we observed no additive or synergistic effect when using them in combination. The expression of transduced p21 and p16 gene products up to days 9 and 12, respectively, was consistent with the growth suppression and cell cycle arrest observed. This work provides information on the previously uncharacterized duration of p21 and p16 transgene product expression and also lends insight into the interaction of these 2 cell cycle regulators in squamous cell carcinoma of the head and neck.

Adenoviruses, Human↗
PubMed1998

Surgical outcomes in head and neck cancer patients 80 years of age and older.

BACKGROUND: Elderly patients over 80 years of age represent a growing population, some of whom have complex medical problems that are compounded by the presence of upper aerodigestive tract cancer. METHODS: Forty-three patients, aged 80 years and older, who were initially seen with head and neck squamous cell carcinoma from 1986 to 1992 at a tertiary-care center were compared with 79 similar patients, aged 65 years or younger, in a retrospective, case-control study. RESULTS: Median overall survival for the patients over 80 years of age was significantly lower than that for the controls (p = .001). However, their overall survival was similar to the actuarial survival for the general octogenarian population. Advanced age also adversely affected local control (p < .001) and disease-specific survival (p = .041). Although the older age group had a higher frequency of morbid preoperative conditions, there were no significant differences in perioperative or postoperative complications between the two groups. CONCLUSIONS: Careful preoperative staging and evaluation of associated medical illnesses, as well as skillful perioperative and postoperative management, are essential for reducing operative morbidity and mortality in the octogenarian patient. Successful outcome depends upon appropriate surgical management, treatment of concurrent illnesses, and minimization of postoperative complications. Individualized surgical management of the elderly head and neck cancer patient is effective, well tolerated, and clinically indicated for upper aerodigestive tract malignancies.

Aged↗
PubMed1998

Differential expression of epidermal growth factor receptor in human head and neck cancers.

BACKGROUND: Over-expression of human epidermal growth factor receptor (EGFR) is associated with a variety of human malignancies, including head and neck cancer. It has also been studied for its effect on cancer cell responses to chemotherapy. To accurately measure changes in EGFR expression that might be of diagnostic or prognostic importance in head and neck cancers, a quantitative assay for the direct detection of EGFR messenger ribonucleic acid (mRNA) was developed. METHODS: Our method was based on competitive reverse transcriptase-polymerase chain reaction (RT-PCR) that was able to measure EGFR mRNA levels undetectable by northern-blot analysis. We measured EGFR mRNA by RT-PCR in human head and neck cancers and their corresponding adjacent, histologically normal tissues and in cisplatin-treated and untreated oral epithelial cell lines. RESULTS: All the tumor samples had higher EGFR mRNA levels than their corresponding adjacent normal tissues. It is also shown that EGFR mRNA levels in normal oral epithelial cells were elevated after exposure to cisplatin. In contrast, EGFR mRNA levels in oral cancer cells were decreased after the exposure, suggesting that increased EGFR expression may have different functions in cancer cells and in normal cells under stress. CONCLUSIONS: Accurate monitoring of EGFR expression may be a useful marker for diagnosis, treatment, and prognosis of head and neck cancer.

Adult↗
PubMed1998

A simple and sensitive method for detecting adenovirus in serum and urine.

A method to detect shed virus in patients' serum and urine was developed following Ad5CMV-p53 gene transfer via direct tumor injections. The procedure differs from those reported previously in that it first uses polyethylene glycol to precipitate adenoviral particles from patient serum or urine. Adenoviral DNA is then extracted following proteinase K digestion. Finally, polymerase chain reaction (PCR) amplification followed by Southern blot transfer are employed to enhance the limit of detection to less than ten viral particles. The detection limit in a 0.25-ml sample is five viral particles in serum and one viral particle in urine. This procedure is sensitive, reproducible, and can be completed in less than 2 days.

Adenoviruses, Human↗
PubMed1998

Genotypic analysis of tumor suppressor genes PTEN/MMAC1 and p53 in head and neck squamous cell carcinomas.

OBJECTIVES: Tumor suppressor gene mutations in both p53 and PTEN/MMAC1 genomic DNA have been detected in many types of cancer. The purpose of this study was to investigate the presence and importance of PTEN/MMAC1 mutations in squamous cell carcinomas. METHODS: Exons of each gene were amplified after polymerase chain reaction (PCR) using genomic DNA derived from cell lines of squamous cell carcinoma of the head and neck (SCCHN) and snap-frozen biopsy specimens from primary established head and neck tumors. The amplified and purified DNA was then sequenced directly. RESULT: As anticipated, point mutations of the p53 gene were found in 80% of cell lines examined. A single base mutation in codon 151 was found in six of 10 cell lines studied. PTEN/MMAC1 gene mutations were found in neither the cell lines tested nor the tumor biopsy samples. CONCLUSION: This study, as well as a large volume of data, confirms that mutations of the p53 gene are frequent events in head and neck cancer cell lines. Although PTEN/MMAC1 gene mutations have been found in a variety of carcinomas, this gene was not found to be mutated in SCCHN cell lines or in primary squamous cell carcinomas of the head and neck. This information is useful for further studies of mutations in these cell lines.

Carcinoma, Squamous Cell↗
PubMed1998

Phase II trial of paclitaxel, ifosfamide, and cisplatin in patients with recurrent head and neck squamous cell carcinoma.

PURPOSE: To assess the activity and toxicity profile of combined taxol (paclitaxel), ifosfamide, and platinum (cisplatin) (TIP) in patients with recurrent or metastatic squamous cell carcinoma (SCC) of the head and neck. PATIENTS AND METHODS: Recurrent or metastatic head and neck SCC patients received paclitaxel 175 mg/m2 in a 3-hour infusion on day 1; ifosfamide 1,000 mg/m2 in a 2-hour infusion on days 1 through 3; mesna 600 mg/m2 on days 1 through 3; and cisplatin 60 mg/m2 on day 1, repeated every 3 to 4 weeks. All were premedicated with dexamethasone, diphenhydramine, and cimetidine. Prophylactic hematopoietic growth factors were not permitted. RESULTS: Fifty-two patients were assessable for response and toxicity; 53 for survival (local-regional recurrence alone in 57% and distant metastasis with or without local-regional recurrence in 43%). Overall response rate was 58% (30 of 52) of patients; complete response rate was 17% (nine of 52) of patients, with six complete responses that continued for a median 15.7+ months. Median follow-up of all patients was 17.7 months. Median survival was 8.8 months (95% confidence interval [CI] 8.1 to 17.5 months). Toxicity was relatively well tolerated and caused no deaths. The most frequent moderate-to-severe toxicity (90% of patients) was transient grades 3 to 4 neutropenia; neutropenic fever occurred in 27%. Grade 3 peripheral neuropathy occurred in three patients, none had grade 4. Grade 3 mucositis occurred in only one patient, none had grade 4. CONCLUSION: TIP had major activity in this setting, with a 58% objective response rate, 17% complete response rate, durable complete responses (six of nine persisting), and relatively well-tolerated toxicity, with no toxic deaths. The activity of TIP, a novel taxol-cisplatin-based regimen, in recurrent or metastatic head and neck SCC should be confirmed in a phase III trial.

Adult↗
PubMed1998

Adenovirus-mediated p53 gene transfer in patients with advanced recurrent head and neck squamous cell carcinoma.

PURPOSE: Standard therapies of head and neck squamous cell carcinoma (HNSCC) often cause profound morbidity and have not significantly improved survival over the last 30 years. Preclinical studies showed that adenoviral vector delivery of the wild-type p53 gene reduced tumor growth in mouse xenograft models. Our purpose was to ascertain the safety and therapeutic potential of adenoviral (Ad)-p53 in advanced HNSCC. PATIENTS AND METHODS: Patients with incurable recurrent local or regionally metastatic HNSCC received multiple intratumoral injections of Ad-p53, either with or without tumor resection. Patients were monitored for adverse events and antiadenoviral antibodies, tumors were monitored for response and p53 expression, and body fluids were analyzed for Ad-p53. RESULTS: Tumors of 33 patients were injected with doses of up to 1 x 10(11) plaque-forming units (pfu). No dose-limiting toxicity or serious adverse events were noted. p53 expression was detected in tumor biopsies despite antibody responses after Ad-p53 injections. Clinical efficacy could be evaluated in 17 patients with nonresectable tumors: two patients showed objective tumor regressions of greater than 50%, six patients showed stable disease for up to 3.5 months, and nine patients showed progressive disease. One resectable patient was considered a complete pathologic response. Ad-p53 was detected in blood and urine in a dose-dependent fashion, and in sputum. CONCLUSION: Patients were safely injected intratumorally with Ad-p53. Objective antitumor activity was detected in several patients. The infectious Ad-p53 in body fluids was asymptomatic, and suggests that systemic or regional treatment may be tolerable. These results suggest the further investigation of Ad-p53 as a therapeutic agent for patients with HNSCC.

Adenoviridae↗
PubMed1998

Combination E2F-1 and p53 gene transfer does not enhance growth inhibition in human squamous cell carcinoma of the head and neck.

Ample data exist contending that wild-type p53 and E2F-1 cooperate to mediate apoptosis, that E2F-1-mediated apoptosis is p53 dependent in some situations, and that E2F-1 can induce accumulation of p53 in mammalian cells. These data support the investigation of the biological consequences of combined wild-typep53 and E2F-1 overexpression in human squamous cell carcinoma of the head and neck (SCCHN) for the purpose of developing apoptosis-inducing molecular intervention strategies for the management of this devastating disease. The recombinant adenovirus (Ad) vectors Ad-p53 and Ad-E2F-1 were used for wild-type p53 and E2F-1 gene transfers, respectively, into SCCHN cell lines TU138 and TU167. SCCHN cells transduced with either p53, E2F-1, or both underwent in vitro growth analysis, which revealed that simultaneous p53 and E2F-1 gene transfer did not result in enhanced growth inhibition. To explain our growth assay findings on the basis of potential negative molecular interactions between E2F-1 and p53, Western and Northern blotting analyses were performed to investigate the differential expression of the downstream p53-transactivated genes, p21Waf1 and BAX, under various p53 and E2F-1 gene transfer conditions. Whereas Western immunoblotting demonstrated that E2F-1 antagonized p53 induction of p21Waf1 and BAX, Northern blotting revealed that this interference was pretranslationally regulated and p53 dependent. Coimmunoprecipitation assay confirmed that the wild-type p53 and E2F-1 gene products formed protein-protein complexes in our cell lines. Our in vitro data demonstrated that in SCCHN, E2F-1 interferes with induction of p53-transactivated genes, probably through the formation of protein-protein complexes. Simultaneous p53 and E2F-1 gene transfer is not therapeutically advantageous in this in vitro model of SCCHN.

Apoptosis↗
PubMed1998

Bystander effect in the adenovirus-mediated wild-type p53 gene therapy model of human squamous cell carcinoma of the head and neck.

In models of human lung and head and neck cancer, there have been anecdotal reports of a bystander effect in wild-type p53 gene therapy, an apoptosis-inducing molecular intervention strategy. These reports do not definitively demonstrate the presence of a bystander effect, nor do they elucidate requirements for or characteristics of this phenomenon. We have investigated human squamous cell carcinoma of the head and neck for the presence and requirements of a bystander effect after wild-type p53 gene transduction. Recombinant adenovirus, Ad-p53, was used for wild-type p53 gene transfers. To investigate the role of intercellular contact between p53-transduced and nontransduced cells in mediating a growth inhibitory (bystander) effect on nontransduced cells, coculturing experiments were conducted on human squamous cell carcinoma of the head and neck cell lines TU138 and TU167. For TU138, 29% growth inhibition of nontransduced cells was demonstrated 3 days after p53-transduced and nontransduced cells were cocultured with intercellular contact. This growth inhibition was abolished when cells were cocultured without intercellular contact. TU167 did not demonstrate a bystander effect under any coculturing condition. Supernatant from Ad-p53-infected TU138 and TU167 cells demonstrated no growth-inhibitory effect on respective nontransduced cells. The bystander effect in the adenovirus-mediated wild-type p53 gene therapy model of squamous cell carcinoma of the head and neck, when present, requires intercellular contact. Possible mechanisms of the observed in vitro bystander effect are discussed.

Adenoviridae↗
PubMed1997

Induction chemotherapy followed by radiotherapy versus radiotherapy alone in patients with advanced nasopharyngeal carcinoma: results of a matched cohort study.

BACKGROUND: Prospective randomized and retrospective studies on adjunctive chemotherapy in patients with advanced locoregional nasopharyngeal carcinoma have yielded conflicting results and the role of chemotherapy in this disease had not been clearly defined. The authors report the results of a single institution, matched cohort study comparing a group of 61 patients with advanced stage nasopharyngeal carcinoma treated with induction chemotherapy followed by radiation therapy with a matched group treated with radiotherapy alone. METHODS: Between 1985 and 1992, 61 patients with advanced locoregional nasopharyngeal carcinoma received induction chemotherapy (cisplatin, 100 mg/m2 on Day 1 and 5-fluorouracil [5-FU], 1000 mg/m2, on Days 1-5) for 3 cycles followed by definitive radiation therapy (CT/RT group). This group was matched with a group of 61 patients from a population of 378 patients who received radiation therapy alone (RT group). Matching characteristics were T classification, N classification, histology, and level of cervical lymph node metastases. These characteristics were found to be significant determinants of distant metastasis (DM) and/or survival in a multivariate analysis that was performed in the entire radiotherapy group. Radiation therapy consisted of 66-72 gray in 6.5 to 7 weeks in both groups. Fifty-nine patients (97%) in both groups had Stage IV disease. Fifteen patients (25%) in both groups had lower cervical lymph node metastases. The tumor histologic types also had similar distribution in both groups. Median follow-up time among surviving patients of the CT/RT group was 4.9 years (range, 1.3-9.8 years). RESULTS: The 5-year cumulative incidence of DM was 19 +/- 5% for the CT/RT group and 34 +/- 6% for the RT alone group (P = 0.019; log rank test). This reduction in distant failure was more prominent in patients with intermediate (N2-N3 disease; upper or midcervical lymph nodes), or high risk (N2-N3 disease; lower cervical lymph nodes) of DM. This reduction in DM translated into improvement in disease free survival (DFS) and overall survival (OS). The 5-year actuarial DFS rates were 64 +/- 6% for the CT/RT group compared with 42 +/- 7% for the RT group (P = 0.015). The 5-year actuarial OS rates were 69 +/- 6% (CT/RT group) and 48 +/- 7% (RT group), respectively (P = 0.012). The incidence of locoregional failure was slightly lower in the CT/RT group, but this difference did not reach statistical significance. There was no significant difference in the incidence and severity of acute mucositis between the two groups during radiotherapy. The 5-year cumulative incidence of Grade 3 or higher late complications was also similar in both groups (5 +/- 3% in the CT/RT group and 8 +/- 3% in the RT group; P = 0.721). CONCLUSIONS: This matched cohort study provides additional evidence that induction cisplatin-5-FU chemotherapy prior to definitive radiation improves freedom from distant metastasis, DFS, and OS for patients with locoregional Stage IV nasopharyngeal carcinoma without increasing treatment-related morbidity.

Adolescent↗
PubMed1997

Strong correlation between c-erbB-2 overexpression and overall survival of patients with oral squamous cell carcinoma.

Overexpression of c-erbB-2 (also known as HER-2/neu) has been found in many human cancers, including head and neck squamous cell carcinoma (SCC). We therefore examined expression of the oncoprotein in oral SCC primary tumor samples and compared its relationship with clinical stages and survival rate. Out of 80 cases of oral SCC, high expression level (++ or +++) of c-erbB-2 was found in 41 cases. Of the 80 cases with follow-up information, 39 were further investigated for the correlation of expression level of c-erbB-2 and survival rate. Overexpression of the oncoprotein was significantly correlated with shorter overall survival, and the patients with low and no expression of c-erbB-2 had much higher survival rates. Overexpression of c-erbB-2 was also significantly correlated with nodal stage and metastasis. We found that high expression level of c-erbB-2 was frequently detected in oral cancer cell lines but not in the other head and neck SCC cell lines. Thus, we conclude that overexpression of c-erbB-2 is a frequent event in oral SCC and is correlated with poor survival and may be used as a poor prognostic factor.

Adolescent↗
PubMed1997

Head and neck squamous cell growth suppression using adenovirus-p53-FLAG: a potential marker for gene therapy trials.

The recombinant wild-type p53 adenovirus has been proven effective against the growth of human head and neck squamous cell cancer (SCCHN) cell lines iir vitro and in a nude mouse model. The addition of a FLAG peptide sequence was used in this study, along with the p53 adenovirus vector as a marker of the site of the gene therapy activity. It provides clear evidence of the exogenous gene product within the transduced carcinoma cells. No alterations in transcription or translation of the p53 gene product were noted with the addition of the FLAG sequence to the original p53 adenovirus vector. Immunohistochemical analysis displayed simultaneous expression of the p53 and FLAG proteins in the infected cells. The p53 protein remained localized to the nucleus, whereas the FLAG protein was additionally noted in the cytoplasm. In vitro growth suppression assays and in vivo microscopic residual tumor model experiments in nude mice showed a similar tumoricidal effect with the p53-FLAG adenovirus vector to that with the previously studied p53 adenovirus vector without the addition of the FLAG sequence. We conclude that the addition of the FLAG octapeptide sequence allows identification of those cells that have been affected by the molecular therapy independent of the endogenous gene expression of the cells. This novel molecular tracer may prove useful in characterizing infection efficiency and in gene therapy trials.

Adenoviridae↗
PubMed1996

Adenovirus-mediated p16/CDKN2 gene transfer induces growth arrest and modifies the transformed phenotype of glioma cells.

The p16 (MTS1/CDKN2) gene localized at the 9p21 chromosomal region encodes for a cell cycle inhibitor protein and is altered in many human cancers. The frequency of p16 alterations in gliomas exceeds 50%. To restore the missing wild-type p16 gene efficiently in glioma cells an adenovirus vector carrying the full length coding sequence of the wild-type p16 cDNA, Ad5RSV-p16, was constructed. Three human glioma cell lines, U251 MG, U-87 MG and D54 MG, that did not express endogenous p16/CDKN2 gene and were easily infected with adenovirus vectors were selected for these experiments. Introduction of the Ad5RSV-p16 in these malignant glioma cell lines directed the biosynthesis of functional p16 protein in the majority of the exposed cells, significantly inhibited cell growth, influenced cell morphology and modified the transformed phenotype of cells including the ability to form colonies in soft agar. Flow cytometric studies revealed that the majority of the Ad5RSV-p16 infected glioma cells were arrested in the G0-G1 phases of the cell cycle. These results suggest that p16/CDKN2 inactivation is a significant factor in the genesis and progression of gliomas and that the restoration of the wild-type p16 protein could have clinical and therapeutic utility.

Adenoviridae↗
PubMed1996

Gene therapy for head and neck cancer. Comparing the tumor suppressor gene p53 and a cell cycle regulator WAF1/CIP1 (p21).

OBJECTIVE: To compare the efficacy of the tumor suppressor gene wild-type p53 with that of cell-cycle regulator WAF1/CIP1 as single-agent gene therapy for squamous cell carcinoma of the head and neck. EXPERIMENTAL METHODS AND DESIGN: Recombinant cytomegalovirus-promoted adenoviruses containing the wild-type p53 or WAF1/CIP1 (p21) genes were transiently introduced into squamous cell carcinoma of the head and neck cell lines. Standard Western blot analysis was used to determine expression in these cells of the proteins encoded by these genes. A nude mouse xenograft model of squamous cell carcinoma of the head and neck was used to investigate the in vivo efficacy of the repeated gene therapy interventions. RESULTS: Western blot analysis showed marked induction of the WAF1/CIP1 tumor suppressor gene product by both the p21 adenovirus and the wild-type p53 adenovirus (as a secondarily transcribed product). In vitro growth curves demonstrated that the wild-type p53 adenovirus significantly inhibited cell growth in these cell lines, whereas direct induction of the p21 gene product did not. Repeated infection with wild-type p53 adenovirus significantly reduced the size of established subcutaneous tumors, whereas infection with a replication-defective viral control did not. CONCLUSION: Wild-type p53 adenovirus exhibits substantial in vitro and in vivo tumor suppressor activity in squamous cell carcinoma of the head and neck cell lines. This tumor suppression is not a function of the induced WAF1/CIP1 (p21) transcriptional product. Further studies are required to investigate the potential for induction of apoptosis by gene therapy.

Adenoviruses, Human↗
PubMed1996

Gene therapy for head and neck cancer.

Head and neck cancer continues to present a major therapeutic challenge to physicians. Recent advances in molecular or gene therapy have allowed us to reassess these malignancies and consider novel strategies for their management. Since the first clinical trial 5 years ago, it has become apparent that gene transfer is no longer a speculative approach for treating malignancies. Gene therapy involves the introduction of genetic material (DNA) into host cells to induce the expression of the therapeutic product of that gene. This review summarizes the most recent data concerning the use of gene therapy as a treatment strategy for head and neck solid malignancies. A brief overview of the basic concepts of gene therapy as well as future potential applications is also discussed.

Adenoviruses, Human↗