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R R Weichselbaum

Publications and source records attributed to R R Weichselbaum.

At least 19 recordsLinked to original sources
PubMed1992

Ionizing radiation activates transcription of the EGR1 gene via CArG elements.

The present studies have examined the effects of ionizing radiation on control of the early growth response 1 (EGR1) gene. Exposure of human HL-525 cells to x-rays was associated with increases in EGR1 mRNA levels. Nuclear run-on assays showed that this effect is related at least in part to activation of EGR1 gene transcription. Sequences responsive to ionizing radiation-induced signals were determined by deletion analysis of the EGR1 promoter. The results demonstrate that x-ray inducibility of the EGR1 gene is conferred by a region containing six serum response or CC(A+T-rich)6GG (CArG) motifs. Further analysis confirmed that the region encompassing the three distal or upstream CArG elements is functional in the x-ray response. Moreover, this region conferred x-ray inducibility to a minimal thymidine kinase gene promoter. Taken together, these results indicate that ionizing radiation induces EGR1 transcription through CArG elements.

Base Sequence↗
PubMed1992

Involvement of reactive oxygen intermediates in the induction of c-jun gene transcription by ionizing radiation.

Previous work has demonstrated that the cellular response to ionizing radiation includes transcriptional activation of the c-jun gene. The signaling events responsible for this response, however, remain unclear. The present studies have examined the effects of ionizing radiation on c-jun expression in a variant of HL-60 cells, designated HL-525, which is deficient in protein kinase C (PKC)-mediated signal transduction. The results demonstrate that these cells express low levels of PKC alpha and PKC beta transcripts and exhibit an attenuated induction of c-jun expression following treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA). In contrast, HL-525 cells respond to ionizing radiation with an increase in c-jun mRNA which is more pronounced than that in wild-type HL-60 cells. These cells similarly respond to ionizing radiation with increased expression of the jun-B, jun-D, c-fos, and fos-B genes. Nuclear run-on assays demonstrate that X-ray-induced c-jun expression in HL-525 cells is regulated by increases in the rate of c-jun gene transcription. Moreover, mRNA stability studies in irradiated HL-525 cells demonstrate that the half-life of c-jun transcripts is prolonged compared to that in wild-type cells. Studies with N-acetyl-L-cysteine (NAC), an antioxidant, suggest that X-ray-induced transcriptional activation of the c-jun gene is mediated at least in part through the formation of reactive oxygen intermediates (ROIs). In this context, H2O2 also induced c-jun expression in HL-525 cells, and this effect was inhibited by NAC.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Nucleus↗
PubMed1992

Occurrence of p53 gene deletions and human papilloma virus infection in human head and neck cancer.

Little is known regarding the molecular genetic events in head and neck carcinoma. Epidemiological evidence suggests that both alcohol and tobacco use are related to the development of these neoplasms, and viral infections have also been postulated to play a role in some tumors. Loss of p53 tumor suppressor gene function has been found in many malignancies and can occur through either gene mutation or by interaction with the E6 protein of oncogenic human papilloma viruses (HPV). Because the mucosal surfaces of the head and neck are exposed to mutagens and HPVs, we studied DNA derived from 30 stage I-IV squamous cell carcinomas of the head and neck (9 primary tumors and 21 early passage cell lines) for p53 gene mutations as well as for the presence of oncogenic HPV DNA. Exons 2 through 11 of the p53 gene were examined using single strand conformation polymorphism analysis followed by direct genomic sequencing of all variants. HPV detection was done using polymerase chain reaction amplification with HPV E6 region type specific primers as well as L1 region degenerate ("consensus") primers; HPV type was determined by restriction fragment length polymorphism analysis of the amplified fragment as well as by Southern blotting of genomic DNA. Sixteen of 30 tumors (53%) had p53 mutations and oncogenic HPV DNA was detected in 3 of 30 (10%) tumors, none of which had p53 mutations. The p53 mutational spectrum observed was characterized by equal frequencies of transversions (6 of 16), transitions (5 of 16), and deletions (5 of 16). This distribution of mutations differs from the spectrum of p53 mutation reported in esophageal (P = 0.05) and lung (P = 0.02) cancers, two other tobacco associated neoplasms. A previously undescribed clustering of 3 mutations at codon 205 was also observed. A trend toward a shorter time to tumor recurrence after treatment was noted for those patients with tumors exhibiting p53 gene mutations, and no relationship between p53 mutations and tumor stage or node status was noted. Alteration in p53 gene function appears common in head and neck cancer, and the mutational spectrum observed may reflect the role of different mutagens or mutagenic processes than those responsible for the p53 mutations in lung and esophageal neoplasms.

Alcohol Drinking↗
PubMed1992

Favorable long-term survival following induction chemotherapy with cisplatin, fluorouracil, and leucovorin and concomitant chemoradiotherapy for locally advanced head and neck cancer.

BACKGROUND: The majority of patients with head and neck cancer die of locoregional recurrence of disease following surgery and/or radiotherapy. PURPOSE: Our purpose was to administer induction chemotherapy, perform surgery, and administer concomitant chemoradiotherapy in rapid sequence and to evaluate their impact on locoregional and distant tumor control. METHODS: Sixty-four patients with previously untreated, locoregionally advanced head and neck cancer received two cycles of cisplatin, bleomycin, and methotrexate (PBM) (33 patients) or cisplatin, fluorouracil (5-FU), and leucovorin (PFL) (31 patients). PFL was given to patients who were unable to receive bleomycin. Local therapy consisted of surgery and/or concomitant chemoradiotherapy with 5-FU, hydroxyurea, leucovorin, and radiotherapy (FHX-L), all administered every other week. RESULTS: Complete and overall induction response rates were 21% and 79%, respectively, for PBM and 29% and 81%, respectively, for PFL. At completion of local therapy, 81% of the patients were disease-free. With a median follow-up of 35 months, the median survival and time to progression are 22 and 17 months, respectively, for PBM and have not been reached for PFL. Locoregional recurrence of disease is 30% for PBM and 26% for PFL. Distant disease progression is 24% for PBM and only 3% for PFL. CONCLUSIONS: The sequencing of induction chemotherapy and concomitant chemoradiotherapy is feasible and results in a high local control rate and in an encouraging survival rate with PFL. The high distant failure (i.e., outside the head and neck area) rate of PBM suggests insufficient systemic activity for that regimen. IMPLICATIONS: Concomitant FHX-L chemoradiotherapy may improve regional control rates of advanced head and neck cancer. Effective systemic therapy may be needed to control systemic micrometastases. PFL, but not PBM, appears to be suitable to accomplish that goal.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Cytogenetic evidence of the multistep origin of head and neck squamous cell carcinomas.

BACKGROUND: Head and neck squamous cell carcinomas are associated with tobacco and alcohol use; therefore, the incidence of this type of tumor is expected to rise in the future as a result of the increasing numbers of female and adolescent smokers. Previous reports of cytogenetic analysis of this type of tumor have implicated a number of chromosomal regions in recurring changes, but no clear pattern of characteristic changes has emerged. PURPOSE: We have undertaken cytogenetic analysis of 10 cell lines which were established from squamous cell carcinomas of the head and neck, to determine the possible sites of additional tumor suppressor genes and oncogenes that may contribute to malignant transformation. METHODS: Metaphases were harvested from cultures of cells in the exponential growth phase, following exposure to Colcemid (demecolcine) at a final concentration of 30 ng/mL for 5 hours. Air-dried slides were G-banded using trypsin and Giemsa. Fifteen metaphases were photographed and fully karyotyped. RESULTS: We observed that several chromosomal regions were lost at high frequency, including 18q (10 of 10 lines), 10p (eight of 10 lines), 3p (six of 10 lines), 8p (seven of 10 lines), and the short arms of the acrocentric chromosomes (seven of 10 lines). Nine of 10 lines had additional copies of 7p. We also noted clustering of breakpoints in a number of chromosome bands, including 1p22, 10q11.2, 11q13, and the short arms of the acrocentric chromosomes. CONCLUSION: The observation of loss of multiple chromosomal regions in a significant number of lines analyzed is consistent with the theory that tumorigenesis occurs as the result of the accumulation of a number of genetic alterations, as proposed for colorectal carcinoma. The high frequency with which these changes are seen suggests that genes located in these regions have a role in the etiology of this type of tumor.

Carcinoma, Squamous Cell↗
PubMed1992

Differential retention of tumor- and differentiation-suppressor functions in cells derived from a human squamous cell carcinoma.

Three morphologically distinct cell lines--F.2a, V, and B.2--were isolated from a single human squamous cell carcinoma. Although all three cell lines can grow indefinitely in culture, they differ in a number of important transformation-related phenotypes. Only B.2 is strongly tumorigenic when injected into the flanks of nude mice, and only V can efficiently grow in semisolid media. The dominance of these traits was investigated by generating somatic cell hybrids among the three cell lines. F.2a was able to suppress the tumorigenicity of B.2 cells, whereas B.2 inhibited the capacity for anchorage-independent growth of V, the latter trait being a function of the ability of these epithelial cells to differentiate when deprived of support. The influence of exogenously added growth factors was also evaluated. This study indicates that the particular tumor we examined consisted of a heterogeneous population of cells with distinct growth and differentiation capacities.

Animals↗
PubMed1992

5-Fluorouracil, leucovorin, hydroxyurea, and escalating doses of continuous-infusion cisplatin with concomitant radiotherapy: a clinical and pharmacologic study.

Cisplatin (CDDP), 5-fluorouracil (5-FU), and hydroxyurea (HU) have individually demonstrated activity against several solid tumors, act synergistically with each other in vitro, and may act as radiation sensitizers. Therefore, we designed a phase I study to determine the maximally tolerated dose of cisplatin as given in addition to our previously described combination of 5-FU, HU, and concomitant radiotherapy (XRT). Patients exhibiting advanced solid tumors requiring palliative XRT were eligible. The regimen consisted of 1 g HU given p.o.b.i.d. on days 1-5, 600 mg/m2 5-FU given i.v. daily by continuous infusion (c.i.) on days 1-5, escalating doses of cisplatin starting at 10 mg/m2 daily given by c.i. on days 1-5, and involved-field XRT carried out on days 1-5. The cycle was repeated every 14 days until the target XRT dose had been reached. In all, 19 patients were entered at the first dose level, and cumulative grade 3-4 myelosuppression was seen in 16 subjects. As no dose escalation was feasible, the chemotherapy was subsequently altered by using the above regimen for cycles 1, 3, 5, and 7 and substituting the less myelosuppressive regimen of 1 g HU given p.o.b.i.d. on days 1-5, 400 mg/m2 5-FU given i.v. daily by c.i., and 100 mg leucovorin given p.o.4 h on days 1-5 for cycles 2, 4, and 6. On this alternating program, 28 patients were treated with escalating doses of CDDP. The dose-limiting toxicity was again myelosuppression, which was prohibitive at a CDDP dose of 20 mg/m2 daily. In the final phase of the protocol, 30 subjects were treated with the above alternating-cycle regimen at a CDDP dose of 20 mg/m2 daily and a decreased HU dose of 500 mg p.o.b.i.d. in an attempt to circumvent the myelosuppression associated with this dose of CDDP. Although severe acute toxicity (cycles 1 and 2) was observed less frequently, cumulative toxicity (all cycles) remained pronounced. The other major toxicity encountered was mucositis, which was particularly pronounced in patients receiving radiation to the head and neck and following leucovorin-containing cycles. Plasma concentrations of free platinum did not correlate with the CDDP dose, possibly due to the narrow range of doses given. Pharmacodynamic modeling demonstrated that the CDDP dose and the HU dose were associated with leukopenia. Antitumor activity was demonstrated in a number of solid tumors particularly non-small-cell lung cancer and head and neck cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Prognostic indicators in node-negative early stage breast cancer.

With the increasing availability of screening mammography, more women are diagnosed as having breast cancers at an early, node-negative stage. The majority of these patients would be cured with total mastectomy or breast conservation treatment. However, about 30% of the patients would have recurrence of disease in distant sites. In recent randomized clinical trials, adjuvant systemic therapy has been shown to reduce the rate of recurrence in these patients. Proper selection of patients for adjuvant therapy is necessary to avoid exposing many patients with low risk of recurrence to treatments for whom the benefit is not justified by the toxicity and the cost. In this article, we review the clinical and pathologic prognostic factors in early stage, node-negative breast cancer patients, including tumor size, nuclear and histologic grades, estrogen and progesterone receptors, menopausal status, proliferative rate, HER-2/neu oncogene amplification, and cathepsin D level. Favorable prognostic factors include tumor size less than or equal to 2 cm, low nuclear and histologic grades, low S-phase fraction, diploid state, low cathepsin-D level, and positive estrogen and progesterone receptor status. The value of HER-2/neu oncogene overexpression is controversial, and further studies are needed to define its role as a prognostic factor in patients with node-negative breast cancer. Based on these prognostic factors, it is possible to identify subsets of patients who have a low risk of recurrence and would not benefit significantly from adjuvant systemic therapy.

Breast Neoplasms↗
PubMed1992

The isoquinoline sulfonamide H7 attenuates radiation-mediated protein kinase C activation and delays the onset of x-ray-induced G2 arrest.

Protein kinase C activation by ionizing radiation in human tumor cell lines participates in the transcriptional activation of genes which may be associated with the phenotypic response of cells to x-rays. We gamma-irradiated cell line RIT-3 (radiation-induced human sarcoma) and quantified the phosphorylating capacity of protein kinase C. Protein kinase C activity increased rapidly and transiently in these cells. The selective protein kinase C inhibitor H7 attenuated radiation-mediated protein kinase C activation when added to cells prior to irradiation. To determine whether protein kinase C activation is associated with radiation-induced G2 arrest, we analyzed the cell cycle distribution of cells following gamma-irradiation. Following irradiation, RIT-3 cells rapidly progressed through G1 and S and subsequently underwent a dose dependent G2 arrest. At concentrations which are selective for protein kinase C inhibition, H7 delayed the onset of radiation-induced G2 arrest. However, there was no difference in the duration of G2 arrest following the addition of inhibitor as compared to cells irradiated without inhibitor. We propose that protein kinase C activation by ionizing radiation is associated with radiation-mediated cell cycle regulation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Gene therapy targeted by ionizing radiation.

Gene therapy used for the treatment of neoplastic diseases is not well localized. Ionizing radiation can be used to activate the transcription of exogenous genes that encode cytotoxic proteins. This may be accomplished through the use of radiation responsive elements distal to the transcription start site of such genes. We discuss this concept and describe a technique which can be used to amplify the signal initiated by localized radiation therapy. These techniques may be used to target gene therapy during the treatment of human neoplasms.

Genetic Therapy↗
PubMed1992

Neoadjuvant PFL augmented by methotrexate and piritrexim followed by concomitant chemoradiotherapy for advanced head and neck cancer: a feasible and active approach.

To increase the complete remission (CR) rate achieved with two cycles of cisplatin, continuous infusion fluorouracil (5-FU) and oral leucovorin (PFL) we added two antifolate drugs, methotrexate (MTX) and the lipophilic piritrexim (PTX), to the combination (PFL-MP). Twenty-eight patients with previously untreated Stage IV squamous cell carcinoma of the head and neck received 2 cycles of cisplatin 100 mg/m2 on day 1 followed by a 5-day continuous infusion of 5-FU at 800 mg/m2/day and 100 mg of leucovorin administered orally every 4 hours. MTX was administered at 40 mg/m2 IV on day 15 and PTX at 75 mg orally twice daily on days 22 to 26, with cycle 2 starting on day 36. After 2 of the first 5 patients had tumor progression between days 15 and 35, the regimen was intensified to MTX 50 mg/m2, PTX 100 mg twice daily and a cycle duration of 28 days. Local therapy consisted of surgery and/or radiotherapy with concomitant 5-FU and hydroxyurea (FHX) administered every other week. Eleven patients (39%, 95% confidence intervals 21-57%) had a CR, 9 (32%) had a PR, and four patients had no response. Four patients were unevaluable for response to PFL-MP. Patients with poor performance status or N3 disease were less likely to achieve a CR. Mucositis following PFL was the dose-limiting toxicity. Local therapy included surgery in 15 patients and FHX chemoradiotherapy in 19 patients. The administration of FHX in this setting proved feasible and the regimen was given near the intended dose intensity in the majority of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Treatment and prognosis of orbital non-Hodgkin's lymphomas.

Twenty patients with orbital lymphomas were treated and followed over a 14-year period. Ten of these patients had well-differentiated lymphocytic lymphoma (WDL), and all of them were clinical stage IE. Five patients had nodular poorly differentiated lymphocytic lymphomas (NPDL), three patients had diffuse histiocytic lymphomas (DHL), one had nodular mixed-cell lymphoma, and one had diffused mixed-cell lymphoma. The patients with WDL received local radiation therapy, and all of them entered completed remissions. The projected survival at 10 years was 100% for these patients. The patients with low-grade lymphomas with advanced disease were treated with chlorambucil and prednisone or cytoxan and vincristine. The patients with high-grade lymphomas received treatment with methotrexate, cyclophosphamide, doxorubicin, vincristine, bleomycin, dexamethasone (mBACOD) or cyclophosphamide, vincristine, methotrexate, cytosine arabinoside, leucovorin (COMLA). The overall survival estimate for all patients was 63% at 10 years. The disease-free survival was 49% at 10 years. The patients with high-grade lymphomas had a poor prognosis, with no survivors after 4 years. This study suggests that patients with WDL usually present with localized disease to the involved orbit, and have an excellent prognosis with radiation therapy alone. Patients with high-grade orbital non-Hodgkin's lymphomas have a poor outcome despite use of aggressive combination chemotherapy regimens.

Aged↗
PubMed1992

The interaction of 5-fluorouracil, hydroxyurea, and radiation in two human head and neck cancer cell lines.

We have investigated the effects of 5-fluorouracil (5-FU) and hydroxyurea (HU) with radiation on two human head and neck squamous carcinoma cell lines. SQ-20B has a D0 of 239 cGy and an S phase fraction of 37%, while SQ-38 has a D0 of 146 cGy and an S phase fraction of 31%. For SQ-20B the surviving fraction at 100 cGy was significantly reduced (p < 0.05) when cells were exposed to HU or to 5-FU or both chemotherapy agents together with radiation. No significant effect was seen for SQ-38 with either chemotherapy agent alone or in combination with radiation as compared with radiation alone. Therefore, additive cytotoxicity between 5-FU and HU and radiotherapy was observed only in a head and neck cancer cell line with a higher D0 and a higher S phase fraction.

Cell Survival↗
PubMed1992

Concomitant chemoradiotherapy with cisplatin, 5-fluorouracil and hydroxyurea in poor-prognosis head and neck cancer.

Based on encouraging results with 5-fluorouracil (5-FU), hydroxyurea, and concomitant radiotherapy in patients with advanced or recurrent head and neck cancer, an attempt was made to modulate the regimen by the addition of cisplatin as a third active agent. A cohort of 26 patients with head and neck cancer of all histologies were entered into a broad phase I study investigating simultaneous radiation therapy, 5-FU (with or without leucovorin), HU, and infusional cisplatin administered on an alternate-week schedule. Eleven patients (group 1) had failed prior curative local therapy and 15 patients (group 2) were considered to have a poor prognosis with standard therapy. The median follow-up was 30 months. The response rate for all evaluable patients was 82% (14/17), and the complete response rate was 65% (11/17). Patients in group 1 demonstrated a high failure rate (9/11), while few group 2 patients failed after treatment (2/15). The median time to progression was 4.4 months in group 1 and has not been reached in group 2. Patients in group 1 failed locally (7/11), while no local failures were observed in group 2. Acute and cumulative hematologic toxicity was encountered at all dose levels and schedules tested and prevented escalation of the cisplatin dose beyond the desired level of 100 mg/m2 per months. Mucositis was a second significant toxicity in patients with head and neck cancer and was more pronounced during cycles containing leucovorin. A detailed analysis of survival, time to progression, and site of failure is presented.

Adult↗
PubMed1992

Molecular targets to overcome radioresistance.

Our laboratory has cultured cells from 23 patients with head and neck carcinoma and 13 patients with soft tissue sarcoma. The data suggest that, in some patients, inherent tumor cell radioresistance contributes to radiotherapy failure. This paper examines possible mechanisms that lead to increased cell survival following radiation exposure, and their potential as targets to overcome the radioresistant patient population.

Antineoplastic Agents↗
PubMed1992

Perspectives on combination chemotherapy with concomitant radiotherapy for poor-prognosis head and neck cancer.

Concomitant chemoradiotherapy has resulted in small increases in disease-free or overall survival for patients with advanced head and neck cancer when single-agent chemotherapy is used. To increase the efficacy of this approach, combination chemotherapy also has been explored. In this setting, acute toxicities are frequently increased, necessitating interruption or protraction of radiotherapy. Despite this fact, pilot trials using 5-fluorouracil-based chemotherapy have indicated high response and encouraging survival rates. Some of these trials will be reviewed, with a focus on studies with 5-fluorouracil, hydroxyurea, and cisplatin conducted at the University of Chicago.

Adult↗