Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0035412 (rhabdomyosarcoma)
 6,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DNA interstrand cross-links are thought to be the cytotoxic lesion resulting from treatment of cells with the chlorethylnitrosoureas (CENUs). We showed in an earlier study that the resistance of xenografts of pediatric rhabdomyosarcoma to therapy with CENUs correlates with levels of O6-alkylguanine-DNA alkyltransferase. We now demonstrate a relationship between levels of the alkyltransferase and CENU-induced cytotoxicity and DNA-interstrand cross-link formation in two cell lines recently established from such rhabdomyosarcoma xenografts. Rh18 cells were derived from the HxRh18 xenograft line, which contains the alkyl-transferase and is relatively resistant to CENUs, and Rh28 cells were derived from the HxRh28 xenograft line, which lacks detectable alkyltransferase activity and is sensitive to treatment with the CENUs. In vitro, Rh28 cells were 5- to 6-fold more sensitive to growth inhibition by 1,3-bis(2-chloroethyl)nitrosourea than Rh18 cells. Extracts of Rh18 cells contained 3.8 units of the alkyltransferase per mg of protein, whereas such activity was undetectable in Rh28 cells, a unit of the alkyltransferase being defined as 1 pmol of [3H] methyl transferred from [3H]methyl-labeled DNA to protein. DNA interstrand cross-links, measured by alkaline elution 6 h after a 1-h pulse treatment with CENU, could not be detected in Rh18 cells but were found in the Rh28 line. The phenotypes of the parental xenograft lines defined by their alkyltransferase levels and by responses to CENU therapy of the mice have clearly been retained in the cultured cell lines, and as predicted, cross-link formation was inhibited in the alkyltransferase-containing Rh18 cells. These two new cell lines thus provide a useful model for studying the role of DNA repair in rhabdomyosarcoma resistance to these alkylating agents.
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PMID:Response of cultured human cell lines from rhabdomyosarcoma xenografts to treatment with chloroethylnitrosoureas. 252 55

N-(5-indanylsulfonyl)-N'-(4-chlorophenyl)-urea (LY186641), a novel anticancer compound, was evaluated against six lines of rhabdomyosarcoma xenografts, each of which was established from tissue biopsies from untreated patients, and additional sublines selected as xenografts for primary resistance to vincristine, melphalan, and ifosfamide. LY186641 was given by oral gavage twice daily for 10 consecutive days or as 5-day courses repeated at 7-day intervals. At the optimal schedule, complete regressions of advanced tumors were obtained in each of the six rhabdomyosarcoma lines. There was no apparent cross-resistance in RMS lines selected for vincristine resistance or against multiple-drug-resistance KB cells in vitro. There was slight cross-resistance in xenografts selected for melphalan resistance, but not in an ifosfamide-resistant line. These results indicate that LY186641 may have significant clinical activity in the treatment of childhood rhabdomyosarcoma.
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PMID:Evaluation of N-(5-indanylsulfonyl)-N'-(4-chlorophenyl)-urea against xenografts of pediatric rhabdomyosarcoma. 259 3

Primary resistance to vincristine (VCR) has been selected in rhabdomyosarcoma xenograft HxRh12 by sequential administration of VCR at 1.5 and subsequently 3 mg/kg/passage. The resistant tumor (HxRh12/VCR-3) was approximately 4-fold resistant to VCR and resistance was stable in the absence of selecting pressure (greater than 2 yr). HxRh12/VCR-3 was 2- to 3-fold cross-resistant to L-phenylalanine mustard (L-PAM) but only slightly cross-resistant to ifosfamide. To determine whether selection for primary resistance to L-PAM conferred cross-resistance to VCR we selected an L-PAM-resistant subline of rhabdomyosarcoma xenograft HxRh28 (HxRh28/L-PAM-13). This tumor was 2- to 3-fold resistant to L-PAM and 3-(p-fluorophenyl)-L-alanyl-3-[m-bis-(2-chloroethyl)-aminophenyl]-L- alanyl-L-methionine ethoxyhydrochloride, cross-resistant to cyclophosphamide and ifosfamide, and completely resistant to VCR under in vivo conditions. Pharmacokinetic studies in HxRh12/VCR-3 showed decreased retention of [G-3H]VCR but not alteration in metabolism. Expression of mdr1, a gene that encodes P-glycoprotein, associated with the multiple drug resistance phenotype, was examined. Expression of mdr1 was detected in both HxRh12 and HxRh28 tumors, sensitive to VCR, but there was no increase in expression in tumors selected for primary resistance to VCR or L-PAM. Data suggest that mechanisms other than those associated with "classical" multiple drug resistance confer resistance in these tumors. In clinical evaluation against childhood rhabdomyosarcoma, L-PAM has demonstrated only slight activity in patients relapsing on conventional therapy (including VCR) but demonstrated marked activity in patients with advanced previously untreated disease. It appears likely, therefore, that cross-resistance between VCR and L-PAM as demonstrated in this model may have clinical significance.
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PMID:Reciprocal cross-resistance in human rhabdomyosarcomas selected in vivo for primary resistance to vincristine and L-phenylalanine mustard. 289 Apr 32

The need for a pretreatment staging system to accurately assess programs of therapy for the various sites and stages of childhood rhabdomyosarcoma has become apparent as detailed analyses of many factors affecting prognosis and treatment choices have been accomplished through the national cooperative trial, the Intergroup Rhabdomyosarcoma Study (IRS). Initiated in 1972, the IRS has thus far used a clinicopathologic grouping system that is based heavily on therapeutic decisions, particularly on whether or not excision is accomplished and the extent of such an operation. The major problem with this and several other staging classifications now in use is that they depend on pathologic data obtained after surgical treatment has been initiated or rejected. In addition, they do not consider histologic variations of this neoplasm which may be important in estimating prognosis. The large body of clinical data now accumulated in the IRS has provided an excellent opportunity for developing a database for evaluating the International Union Against Cancer (UICC) pretreatment staging system and also the potential for using histologic categories in the staging process. The records of 505 eligible patients entered into the IRS between 1978 and 1982 were used to determine the prognostic impact of a number of pretreatment factors. These included local invasiveness of the primary neoplasm on clinical examination, tumor size, clinical status of regional nodes, clinical or radiologic evidence of distant metastases, and favorable or unfavorable histologic categories. A retrospective assessment of the relationship of these pretreatment observations to survival experience has been carried out. This retrospective study indicates definite prognostic significance for all of the individual factors used on the UICC system except clinical status of regional nodes. Also, these data serve as a basis for considering the possibility of including favorable v unfavorable histology in the pretreatment staging system now being tested prospectively in the ongoing IRS protocols.
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PMID:Prognostic significance of staging factors of the UICC staging system in childhood rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study (IRS-II). 354 38

Vincristine (VCR) is an effective agent in the treatment of childhood rhabdomyosarcoma. Clinically, schedules differ in frequency of administration. To determine the influence of administration frequency, accumulation of VCR in xenografts of human rhabdomyosarcoma has been evaluated following administration of drug at 7- or 21-day intervals. Accumulation was estimated from initial uptake, retention of unchanged drug in tumor tissues, tumor sensitivity, and growth rate. Data suggested that scheduling VCR every 7 days would be more effective than every 21 days, due to more rapid accumulation to cytotoxic levels. The effect of scheduling was examined in two rhabdomyosarcoma xenografts, where in vivo responses were similar to those predicted based upon drug uptake, retention, and growth characteristics for the tumors. Scheduling VCR at 7-day intervals was clearly superior to administration at 21-day intervals in these models.
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PMID:Scheduling of vincristine: drug accumulation and response of xenografts of childhood rhabdomyosarcoma determined by frequency of administration. 360 83

A comparative study of beta enolase and myoglobin as markers of muscle differentiation in rhabdomyosarcoma was carried out, using an immunoperoxidase peroxidase antiperoxidase technique. Material from 26 cases of childhood rhabdomyosarcoma was studied and subdivided into embryonal and alveolar types. Positive cytoplasmic staining for beta enolase was seen in 85% of tumours studied (91% alveolar, 79% embryonal), whereas positive staining for myoglobin was detected in only 69% of tumours (82% alveolar, 64% embryonal). beta Enolase and myoglobin are useful in the histological diagnosis of rhabdomyosarcoma, and of the two, beta enolase seems to be the more sensitive.
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PMID:Comparison of beta enolase and myoglobin as histological markers of rhabdomyosarcoma. 390 69

A case of childhood laryngeal rhabdomyosarcoma is described with a 42 month follow-up and with no evidence of recurrent disease. Treatment included partial excision, postoperative radiotherapy, and chemotherapy with vincristine, actinomycin D, and Cytoxan. Normal laryngeal function has been maintained. Earlier modes of therapy would probably have included total laryngectomy. Recent advances in the combined therapy of childhood rhabdomyosarcoma are reviewed. Resulting cure rates approach 100 per cent in favorable cases. The concept of limited surgical therapy is discussed and is applied to this case.
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PMID:Combination therapy for laryngeal rhabdomyosarcoma. 616 51

Forty-five years following surgical excision and radiation for a childhood rhabdomyosarcoma of the left orbit, a patient with primary lymphedema developed an ipsilateral malignant melanoma of the anterior orbital tissue. This was excised, but a metastasis of the melanoma occurred in the contralateral upper lid. This is the first case report of treated rhabdomyosarcoma of the orbit followed by a second primary tumor occurring in the field of radiation.
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PMID:Rhabdomyosarcoma and late malignant melanoma of the orbit. 665 3

The determinants of intrinsic sensitivity to Vinca alkaloids in vivo were examined in 3 pediatric rhabdomyosarcoma xenografts maintained s.c. in immune-deprived mice. The three lines differed in their sensitivity to VCR and VLB: two lines (Rh12 and Rh28) were extremely sensitive to VCR, whereas Rh18 tumors were less sensitive. Rh28 tumors were also very responsive to VLB, which demonstrated only marginal activity in the other two lines. After administration of equimolar doses (3 mg/kg) of [3H]-VCR and [3H]VLB to tumor-bearing mice, [3H]VCR reached concentrations approaching 1.5 microM in cell water of each tumor line within 4 hr, at which time greater than 93% of the drug was cell-associated. The drug was subsequently retained at this level for at least 72 hr studied. [3H]VLB accumulated to lower maximal concentrations (approximately equal to 1 microM) within 8 hr, but was not retained and, by 72 hr, reached concentrations that were 3- to 4-fold lower than those of [3H]VCR. The extent of drug retention correlated with the antitumor activity except in Rh28 tumors, which were sensitive to VLB, but did not retain the drug. The threshold level for achieving cytotoxicity may, thus, be very low in this line. In normal tissues, maximal concentrations of both [3H]VCR and [3H]VLB were achieved within 1 hr of administration i.p. to tumor-bearing mice. In ileum, liver, and kidney, these were approximately 10-fold higher than the peak levels achieved within tumors or plasma, but declined rapidly to parallel the decrease in plasma reaching concentrations greater than 5-fold lower than the concentration of [3H]VCR in tumors at 72 hr after treatment. Drug concentrations in skeletal muscle also declined rapidly, whereas neither [3H] VCR nor [3H]VLB accumulated to any great extent in brain. The blood volumes of ileum, kidney, and liver were greater than for tumor tissues. Hence, the extent of drug delivery did not necessarily influence therapeutic selectivity. In the case of [3H]VLB, concentrations in tumors approached those of normal tissues at 72 hr after injection. At 24 hr after treatment, 86 to 99% of [3H] VCR and 78 to 90% of [3H]VLB were present in tumors as the parent compound, which also predominated in normal tissues. Metabolites or in vivo degradation products were also identified. Selective retention in tumors appears to be the mechanism by which therapeutic selectivity is achieved with VCR in rhabdomyosarcoma xenografts.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Determinants of intrinsic sensitivity to Vinca alkaloids in xenografts of pediatric rhabdomyosarcomas. 669 63

Cooperative clinical trials groups offer exciting opportunities for conducting epidemiologic research for several reasons: they facilitate accrual of sufficient numbers of subjects in a short period of time, even for studies of rare diseases; they provide uniform pathologic review and uniform collection of subjects' entry data; and they provide a more representative sample of cases than a single-institution study. Despite these advantages, few epidemiologic studies of etiologic factors have been done through these groups because methods for selecting appropriate control subjects and for obtaining information from geographically scattered subjects have not been available. An approach that can serve as a model for this type of research has been developed. A collaborative case-control study of childhood rhabdomyosarcoma (RMS) with the Intergroup Rhabdomyosarcoma Study (IRS) was recently begun. The study, which is independently funded, evaluates the role of environmental factors in the etiology of RMS. Parents of subjects were interviewed by telephone and control subjects were selected from the same communities as patients by random digit dialing . Interview data are supplemented by information from birth certificates and, for patients, by IRS data. This new methodology permits a large study of a rare tumor in a relatively short period of time.
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PMID:An approach to conducting epidemiologic research within cooperative clinical trials groups. 672 5


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