Chemotherapy For Neuroblastoma Research Articles

Expression of the multidrug resistance, MDR1, gene in neuroblastomas.

Metastatic neuroblastoma is a childhood malignancy that is frequently responsive to chemotherapy with doxorubicin, vincristine, and teniposide (VM26), among other drugs, but in the majority of treated patients, the tumor recurs during or after chemotherapy. In this work, we have examined the hypothesis that the development of resistance to chemotherapy in neuroblastoma might be related to the expression of the human MDR1 gene, which encodes a multidrug transporter that functions as an energy-dependent drug efflux pump. RNA samples from 49 neuroblastomas were analyzed, including 31 from untreated and 18 from treated patients. MDR1 RNA was detectable in the majority of treated and untreated tumors using a sensitive, semiquantitative slot blot assay. Of the samples from treated patients, five of 18 were found to have high MDR1 RNA levels, whereas only three of 31 from untreated patients had high MDR1 levels, a statistically significant difference (P less than .01). These results show that high levels of MDR1 RNA are often associated with resistance to chemotherapy in neuroblastoma and suggest that they may contribute to this resistance. Many of the neuroblastoma samples were also evaluated for N-myc amplification but there was no correlation between N-myc copy number and the level of MDR1 mRNA expression.

Correlation of MDR1 gene expression with chemotherapy in neuroblastoma.

Forty-one neuroblastoma tumor specimens have been analyzed by Northern and slot blot hybridization techniques with human MDR1 gene probes. Only one of 15 (6%) tumors from patients who had not received chemotherapy exhibited high levels of MDR1 transcripts, while 11 of 26 (42%) treated tumors showed high levels of MDR1 expression (Fisher exact test: P = .03). The results indicate that the level of MDR1 mRNA expression is associated with previous chemotherapy, including drugs that select the multidrug resistance phenotype in vitro regardless of neuroblastoma tissue origin or N-myc content in the genome. For the 26 treated neuroblastomas, the number of nonresponsive tumors was found to be significantly higher among those with high levels of MDR1 mRNA.

Uptake and release of iodine-labelled m-iodobenzylguanidine in a neuroblastoma cell culture system and its importance in neuroblastoma therapy.

A neuroblastoma cell line was established from bone marrow of a patient in stage IV of the disease and used as a model system in order to elaborate experimental data of importance in neuroblastoma therapy, such as cell-drug interactions, the mode of uptake and conditions for storage and release. m-Iodo benzylguanidine (MIBG) is rapidly taken up from culture medium, giving high concentrations of cell-bound radioactivity reaching a maximum level 4 h after the addition of the compound. A removal of the radiopharmacon from the culture medium causes a dramatic loss of cell-associated radioactivity, suggesting that neuroblastoma cells are not able to retain MIBG in a drug-free environment. Replacement of labelled by unlabelled MIBG prevents a similar release and maintains high levels of cellular radioactivity. Variations of cell culture conditions only result in minor changes of uptake rates, whereas a pretreatment with drugs used in neuroblastoma chemotherapy harms the cells extensively: even after a short-term exposure the cells lose the capacity for MIGB uptake and fail to recover within a long period of incubation in growth medium. The importance of our results is discussed, leading to the following suggestions: 1. The performance of radiotherapy with labelled MIBG is recommended prior to the chemotherapy protocols. 2. Therapeutically effective radioactivity in tumor tissues may be maintained by the additional infusion of unlabelled MIGB.

Adjuvant chemotherapy for murine neuroblastoma with special reference to cell kinetics of residual tumor after primary tumor removal.

We examined the effect of adjuvant chemotherapy for neuroblastoma (C-1300NB) after surgery, especially on the increase in cells in the DNA synthetic phase in the remaining neuroblastoma from the 6th to 24th postoperative h caused by the reduction of the tumor cell in the tumor-bearing A/J mice. The mice were inoculated with C-1300NB cells in the chest and leg simultaneously, and administered adriamycin (ADM), as a cell cycle phase-specific agent, or cyclophosphamide (CPM), as a cell cycle phase nonspecific agent. The growth rate of chest tumors (residual tumors) in the mice treated with ADM just after amputation of the tumor-bearing leg was significantly lower than that of the other groups (p less than 0.05). 3H-TdR labeling indices of chest tumors in this group decreased more effectively than in the other groups. These results indicate that it is important to administer a cell cycle phase-specific agent rather than a cell cycle phase nonspecific agent during the period of rapid growth of residual tumors after surgery.

Effects of Glucose on Neuroblastoma In Vitro and In Vivo

Because neuroblastoma cells in vitro are sensitive to changes in glucose levels in growth media, the effects of glucose levels and dietary carbohydrate on the sensitivity of neuroblastoma cells to chemotherapy were studied. In vitro, 20 μM bromoacetylcholine, 3mM 1,3-diaminopropane, and 5mM 5-fluorouracil were added to the growth medium of strain N2a neuroblastoma cells cultured in Dulbecco's modified Eagle medium with high glucose (4.5g/L, HG), normal glucose (1.0g/L, NG), or low glucose (0.1g/L, LG). Diaminopropane and 5-fluorouracil had some cytotoxic effect on cells in all media. Bromoacetylcholine killed cells in all media, but at a concentration of 20 μM was most effective in LG medium. Mice (A/Jax) were inoculated with neuroblastoma cells for in vivo studies. Mice could not tolerate a carbohydrate-free diet, while a high-carbohydrate diet caused no change in survival time. When mice on a high carbohydrate diet were treated with cyclophosphamide (100mg/kg, ip) or 5-fluorouracil (125mg/kg, ip), they died faster than drug-treated mice on a normal diet. Oral chlorpropamide or cimetidine did not prolong survival time. Analysis of blood glucose levels showed neuroblastoma significantly lowered blood glucose levels (p <0.05), while chlorpropamide had no significant effect. It is proposed that manipulation of plasma glucose to lower levels will not be effective in enhancing the chemotherapy of neuroblastoma.

Purine metabolism in human neuroblastoma cell lines.

Neuroblastoma is the second most common solid tumor of childhood, originating from the embryonic neural crest (1). The clinical picture is polymorphic due to varied histological patterns, different localization and different degrees of malignancy. Despite aggressive I treatment, the overall prognosis has not changed in the last 2 decades. There are only few reports on clinical trials with drugs j affecting nucleotide metabolism, such as methotrexate (2) and trifluoromethyl-2-deoxyuridine (3). In the present study we describe in detail the metabolism of purine nucleotide as a possible target for chemotherapy in neuroblastoma. Two different human neuroblastoma cell lines established from surgically resected tumor were used in this study, NUB-6, from a patient with a localized disease and EW-2 from a patient with recurrent metastatic disease. The cells were grown in alpha-medium supplemented with 20% inactivated fetal calf serum. EW-2 f cells formed monolayers whereas NUB-6 cells formed spheroid-like aggregates with an average size of 400 μm. All assays were performed on a single cell suspension achieved by gentle shaking in citrate-saline and mild trypsinization for two minutes. Viability of over 95% was kept through all experiments. The availability of twof biologically different cell lines may allow us to relate changes in nucleotide metabolism to these phenotypic differences. For the assessment of nucleotide metabolism, labelled adenine, hypoxanthine, adenosine, guanosine, formic acid and glycine were used, and the incorporation of radioactivity into the respective purine ribonucleotides, ribonucleosides and bases was assayed as previously described (4). The cytotoxic effect of a number of drugs was evaluated in a clonogenic assay (6).KeywordsNeuroblastoma Cell LineClonogenic AssayPurine MetabolismPurine NucleotideNucleotide MetabolismThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Recovery of bone marrow phagocytic activity after chemotherapy for neuroblastoma

An 11 year old girl, with biopsy proven neuroblastoma cells in the bone marrow, had lack of uptake of 99 m Tc-sulfur colloid in marrow of the pelvic area. Her chemotherapy was changed. A repeat image 25 days later then showed accumulation of radiocolloid in the pelvic region.

Pharmacokinetic studies in the chemotherapy of neuroblastoma using the C1300 murine system.

The transplantable C1300 murine neuroblastoma has been characterized biochemically and an in vivo model for the screening of new therapeutic approaches to the treatment of neuroblastoma developed. Subcutaneous inoculation of A/J mice with 10)6) C1300 cells results in predictable tumor growth and animal death in 25 +/- 4 days. Tumor growth is Gompertzian, correlates with increases in tumor RNA and DNA content and with the rate of tumor DNA synthesis as measured by [3H] thymidine incorporation. The model proposed is based on the degree to which various therapeutic options are able to inhibit tumor DNA synthesis, and these observations have been confirmed autoradiographically. A single course of either cyclophosphamide (25, 50, 100 or 200 mg/kg), BCNU (2, 7.5, 15, or 30 mg/kg) or cytosine arabinoside (15, 30, 60, 90 mg/kg) resulted in dose-related inhibition of tumor DNA synthesis. The maximum decline in DNA synthesis that was produced by the highest dose of each agent was by 81%, 77% and 68% of untreated tumor values respectively. Adriamycin, however, even at lethal levels (10 mg/kg), did not elicit significant inhibition of tumor DNA synthesis. Radiotherapy (200 R, 500 R or 1000 R) also produced graded inhibition of tumor DNA synthesis. This model is potentially useful for the preclinical screening of therapuetic options in the treatment of neuroblastoma. Thus, single agent therapy, combination chemotherapy and combined radiotherapy and chemotherapy may be rapidly evaluated for possible clinical use.

Chemotherapy of neuroblastoma

Chemotherapy of neuroblastoma

Chemotherapy of neuroblastoma

Chemotherapy of neuroblastoma

Chemotherapy in neuroblastoma

Chemotherapy in neuroblastoma