Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A line of P388 leukemia resistant to mitomycin C (MMC) was successfully developed in vivo by treating mice bearing parental P388 (P388/0) with MMC followed by serial passage of the surviving leukemic cells. From this P388/MMC line, a subline was derived by not treating the passage mice with MMC (P388/MMC-NP); resistance to MMC was stable for as many as 56 weeks of transplantation. The chemosensitivities of each P388 line to assorted anticancer drugs were compared in vivo. Both P388/MMC and P388/MMC-NP had similar patterns of drug cross-resistance and collateral sensitivity. With respect to alkylating agents (e.g. cyclophosphamide, Platinol and chlorambucil), there was generally a partial degree of cross-resistance, sometimes only detectable at suboptimal dose levels. With respect to DNA binders or intercalators (e.g. actinomycin D, luzopeptin A, amsacrine, doxorubicin), the extent of cross-resistance varied from none (dihydoxyanthraquinone) to marked (doxorubicin). Antimitotic inhibitors (vinblastine and vincristine) were completely cross-resistant, as were some miscellaneous natural agents (rebeccamycin, VP-16, sesbanimide, and elsamicin, a chartreusin analog). Antimetabolites (e.g. methotrexate and 6-thioguanine) showed no cross-resistance and even demonstrated some occasional evidence of collateral effectiveness.
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PMID:In vivo characterization of P388 leukemia resistant to mitomycin C. 297 64

The anticancer agent etoposide (VP-16) produces DNA strand scission in intact tumor cells or isolated nuclei. This activity may be mediated by topoisomerase II, an enzyme capable of producing double strand breaks in mammalian cells. Two established tumor cell lines were examined to see whether polyamines, which alter DNA conformation and topoisomerase II activities, affected the cytotoxicity, strand scission, and antitumor efficacy of VP-16. L1210 murine leukemia and 8226 human myeloma cells were treated with alpha-difluoromethylornithine (DFMO) to reduce intracellular polyamine levels via inhibition of ornithine decarboxylase. The polyamines putrescine and spermidine were markedly reduced by a 48-h incubation with 50 microM DFMO. This DFMO concentration did not inhibit colony formation in either cell line, but did reduce the growth rate of both cultures. In contrast, VP-16 produced a dose-dependent inhibition of colony formation. This was especially marked in the 8226 cell line. This correlated with DNA single strand breaks (SSBs) detected by the alkaline elution technique. When cells previously treated with DFMO were exposed to VP-16, a synergistic inhibition of colony formation (determined by isobologram analysis) was observed. However, VP-16-induced SSBs were only marginally increased by the DFMO pretreatment. When putrescine was combined concurrently with VP-16, both the in vitro cytotoxic effects and the number of DNA SSBs in L1210 cells were significantly reduced. These results demonstrate that putrescine inhibits VP-16-induced SSBs and commensurate cytotoxic effects, while DFMO, which depletes intracellular putrescine and partially reduces intracellular spermidine, acts to produce synergistic cytotoxic effects when combined with VP-16.
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PMID:Modulation of etoposide cytotoxicity and DNA strand scission in L1210 and 8226 cells by polyamines. 301 79

The presumptive intracellular target of the anti-leukemia agents 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) and 4-(4,6-O-ethylidene-beta-D-glucopyranoside) (VP-16) is the enzyme topoisomerase II. We found that 350 mM NaCl extracts of nuclei from HL-60 and HL-60/AMSA, an m-AMSA resistant HL-60 subline, contained equivalent topoisomerase II activity. However, the ability of m-AMSA to stimulate cleavage of exogenous DNA and to stimulate crosslinking of exogenous DNA with protein, processes which are topoisomerase II-mediated, was greatly reduced in the HL-60/AMSA extracts compared to the HL-60 extracts. HL-60 and HL-60/AMSA were almost equally sensitive to the cytotoxic effects of VP-16 and differences in VP-16-stimulated, topoisomerase II-mediated exogenous DNA cleavage and protein crosslinking between HL-60 and HL-60/AMSA extracts were much less than the differences in m-AMSA-stimulated exogenous DNA cleavage and protein crosslinking. Thus, the interaction between topoisomerase II activity, exogenous DNA, and m-AMSA or VP-16 indicated the susceptibility HL-60 and HL-60/ AMSA to the cytotoxic effects of the drugs. A similar correlation may exist in explanted leukemia cells from patients with acute myelogenous leukemia.
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PMID:The interaction between nuclear topoisomerase II activity from human leukemia cells, exogenous DNA, and 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) or 4-(4,6-O-ethylidene-beta-D-glucopyranoside) (VP-16) indicates the sensitivity of the cells to the drugs. 303 64

Thirty-eight patients (median age, 21 years) with acute nonlymphoblastic leukemia (ANLL) (17 patients), acute lymphoblastic leukemia/lymphoma (ALL) (18 patients), chronic myelogenous leukemia (two patients), and refractory anemia received allogeneic bone marrow transplants from HLA-identical sibling donors or a one-antigen-mismatched brother (one patient) after a preparatory regimen consisting of fractionated total body irradiation and high-dose VP 16-213 (60 to 70 mg/kg body weight). Of the 33 patients with acute leukemia who received grafts from HLA-identical donors, three patients with ANLL received transplants in first remission and one patient with standard-risk ALL received a graft while in second remission. All other patients were in more advanced stages of their disease or exhibited other high-risk features. At the time of analysis, 20 of the 33 patients were alive, with 19 of them remaining in continued complete remission for 6 to 35 months (median, 18 months). The 3-year actuarial disease-free survival rate of 56.6% +/- 9.7% (SE) and the actuarial relapse rate of 11.9% +/- 6.8% (SE) demonstrate that the combination of fractionated total body irradiation and high-dose VP 16 is an effective mode of therapy in patients with advanced leukemias. Preliminary experience cautions against the use of VP 16 instead of cyclophosphamide in any clinical situation carrying an increased risk of graft rejection because the immunosuppressive potency of VP 16 is largely untested but may be inferior to that of cyclophosphamide.
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PMID:Fractionated total body irradiation and high-dose VP 16-213 followed by allogeneic bone marrow transplantation in advanced leukemias. 305 26

All clinical studies in the English literature from 1976 to mid-1987 that address drug management of refractory or relapsed ANLL are reviewed and summarized. We conclude that, although many regimens may induce a CR, none is clearly superior. New drugs and or drug combinations must be sought if treatment outcomes are to be substantially improved. At present it appears that combination chemotherapy with VP-16 has not been extensively studied and may be active in non-cross-resistant regimens.
Leukemia 1988 Nov
PMID:Impact of reinduction regimens on the clinical course of adult acute nonlymphocytic leukemia. 305 48

Thirty-five patients with acute myelogenous leukemia were treated with aclacinomycin A (60 mg/m2/day for 5 days) and VP-16-213 (100 mg/m2/day for 5 days). All were previously treated and had relapsed or were refractory to primary treatment. Most patients (28) had received prior DAT (daunorubicin, cytosine arabinoside, and 6-thioguanine) induction therapy followed by one or more courses of high-dose cytosine arabinoside (HD-Ara C) as consolidation therapy or as treatment for relapse. One patient was in her fourth relapse, one had relapsed acute megakaryoblastic leukemia (following remission with DAT and HD-Ara-C), one had a treatment-induced leukemia, and four patients were treated for primary treatment failures following two induction courses with DAT or a similar regimen. Fourteen patients had infections at start of therapy. Ten patients died within 14 days of treatment, all from sepsis or bleeding, before their marrow could be evaluated for leukemic response. Fourteen patients (40%) responded; 12 (34%) entered complete remission and two (6%) a partial remission (PR). Two of the four patients who were treated for primary treatment failures went into CR. The median CR duration was 99 days (range 30 to 455 days). Side effects from this treatment were similar to the conventional DAT regimen, although the gastrointestinal toxicity and mucositis appeared to be more severe. In addition, two of the patients had severe but reversible ventricular arrhythmias. The overall response (40%) and CR rate (34%) in this group of previously treated AML patients is encouraging, and further studies are needed to evaluate these preliminary findings.
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PMID:Aclacinomycin A and etoposide (VP-16-213): an effective regimen in previously treated patients with refractory acute myelogenous leukemia. 316 95

In an attempt to find how much the low therapeutic effectiveness of antitumor drugs against so-called chemotherapy-refractory tumors such as colon carcinoma depends on drug sensitivity at the cellular level, sensitivity of five carcinoma cell lines (three colorectal, one pancreatic, and one renal) to nine typical anticancer agents was compared in vitro with that of four generally chemotherapy-susceptible leukemia cell lines. Sensitivity was assessed in terms of the percentage cell growth in control cultures, which was determined by exposing exponentially growing cells for 48 h to the following antitumor drugs: 1-(4-amino-2-methylpyridine-5-yl)-methyl-3-(2-chloroethyl)3-nitrosourea hydrochloride (ACNU), adriamycin (ADM), bleomycin (BLM), cisplatin (DDP), etoposide (VP-16), 5-fluorouracil (5FU), mitomycin C (MMC), methotrexate (MTX), and vinblastine (VLB). As expected, 10-fold or greater differences in sensitivity were scarcely ever observed between the two kinds of cell lines. Thus, we recorded a result of more (or less) sensitivity when there was a difference of 3-fold or more; and compared the drug sensitivity in every pair of carcinoma and leukemia cell lines (20 pairs for each drug). We found that carcinoma cell lines were less sensitive to VP-16, ADM, DDP, and MTX than leukemia cell lines in 18, 15, 12, and 10 of 20 pairs, respectively; only one opposite case was observed, with DDP. On the other hand, no such tendency between the two groups was observed with BLM, 5FU, or MMC. Overall, significantly different sensitivities were observed between them in 91 out of 180 pairs (i.e., 9 antitumor drugs x 5 carcinomas x 4 leukemias), and carcinoma cell lines were less sensitive than leukemia cell lines in 79 of these 91 pairs. These results suggest that the refractoriness of colon carcinoma, etc. to chemotherapy is, at least in part, due to low drug sensitivity of the tumor cell itself.
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PMID:Comparison of cellular basis of drug sensitivity of human colon, pancreatic, and renal carcinoma cell lines with that of leukemia cell lines. 316 59

The sequence-dependence of the antitumor effect of etoposide (VP-16) and 1-beta-D-arabinofuranosylcytosine (ara-C) was investigated against the L1210 ascites tumor in BDF1 mice. Treatment with VP16 (7.5 or 15 mg/kg) and ara-C (25 or 500 mg/kg) was administered intraperitoneally on days 1, 4 and 7 after tumor inoculation. Six hour pretreatment with 15 mg/kg VP16 followed by 500 mg/kg ara-C yielded a 100% cure rate, but only a 20% cure rate was obtained with the reverse sequence. Simultaneous administration of 15 mg/kg of VP-16 and 500 mg/kg ara-C interacted synergistically, producing a 70% cure rate. In contrast with the results obtained with VP-16 and 500 mg/kg ara-C, simultaneous administration of 25 mg/kg ara-C neither antagonized nor potentiated the antitumor effect of VP-16. Twenty-five mg/kg ara-C was too low to produce any antitumor effect with VP-16 in simultaneous administration. At every dose investigated, pretreatment with VP-16 followed by ara-C was the most effective antitumor schedule in L1210 leukemia. This sequence of drug administration did not cause greater toxicity as measured by weight loss or toxic death.
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PMID:Sequence-dependent antitumor effect of VP-16 and 1-beta-D-arabinofuranosylcytosine in L1210 ascites tumor. 322 79

We tested the value of early intensification of chemotherapy in 68 consecutive children with acute nonlymphocytic leukemia (ANLL) who were admitted to St. Jude Children's Research Hospital from November 1983 through March 1987. Fifty-eight patients (85%) entered complete remission after treatment with etoposide (VP-16)/cytarabine (ara-C) (A), followed by daunorubicin (Dauno)/ara-C/thioguanine (6-TG) (B) and then VP-16/azacytidine (5-AZ) (C). Thirty percent of the complete responders, mainly those with an M4 or M5 leukemia subtype, attained M1 marrow status after component A, 60% after A + B, and 10% after A + B + C. Induction failures resulted primarily from absolute or relative drug resistance; there was only one death during this phase of therapy. Postremission treatment consisted of three pairs of drugs (vincristine [VCR]/amsacrine [m-AMSA], or doxorubicin [Doxo]/6-TG/ara-C, and VP-16/cyclophosphamide [CTX]) administered sequentially in 6-week cycles for 22 months. Despite the high rate of remission induction, only 33% +/- 7% SE of the patients are expected to be failure-free survivors at 2 years. Remission durations were not significantly affected by the majority of factors examined in this study, with the exception of marrow cellularity after VP-16/ara-C induction therapy. Patients with less than or equal to 5% leukemic cells survived relapse-free for a median of 36.1 months, compared with 11.3 months for the group with a larger infiltrate (P = .01). Although postremission therapy did not improve the percentage of long-term failure-free survivors, the induction regimen we used appears highly effective, and its components should be considered for inclusion in other treatment programs.
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PMID:Early intensification of chemotherapy for childhood acute nonlymphoblastic leukemia: improved remission induction with a five-drug regimen including etoposide. 329 13

Having reviewed conventional chemotherapy of acute leukaemia in the preceding article, a discussion of high dose chemotherapy in haematological malignancy is presented. The indications and side-effects of high dose methotrexate, ifosfamide and etoposide (VP-16) are summarized in tabular form. The toxicity and effectiveness of high dose cytosine arabinoside in the treatment of refractory acute leukaemia is discussed. The use of high dose melphalan to treat patients with multiple myeloma or other tumours is reviewed. The most widely used cytoreductive regimes in bone marrow transplantation, high dose busulphan, high dose cyclophosphamide and total body irradiation are described.
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PMID:Therapeutic progress--review XXVII. High dose chemotherapy in haematological malignancy. 330 28


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