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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eight human haematopoietic cell lines and four human carcinoma lines were used to compare the activity of a number of cytotoxic drugs including amsacrine, the amsacrine analogue CI-921, methotrexate, nitracrine, doxorubicin, daunorubicin and 5-fluorouracil. Activity was assessed by means of semiautomated microculture growth inhibition assays. Cell density of the non-adherent cell lines was measured using the technique of Mosmann (J Immunol Methods 1983, 65, 55-63), in which the dye thiazolyl blue (MTT) is metabolised to a dark blue formazan product. This technique gives similar results to those obtained by direct cell counting in an electronic cell counter, and when applied to some adherent cell lines gives similar results to those obtained by the methylene blue staining technique previously developed (Anal Biochem 1984, 139, 272-277). Both methylene blue and MTT methods were used to investigate cytotoxicity in conjunction with semi-automated 96-well microculture plate techniques. The results show that the three T-cell leukaemia lines (CCRF-CEM, Jurkat and MOLT-4) are more sensitive to DNA-binding drugs (excluding nitracrine) than are the colon carcinoma lines (HCT-8, HT-29, SW480 and SW620). The more resistant haematopoietic lines are intermediate in drug sensitivity between the T cell leukaemia and carcinoma lines. The DNA binding drugs show remarkably similar patterns of differential activity against the different cell lines.
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PMID:Comparison of in vitro activity of cytotoxic drugs towards human carcinoma and leukaemia cell lines. 375 82

Cellular drug resistance is supposed to play a major role in chemotherapy failures which frequently occur in childhood acute non-lymphoblastic leukemia (ANLL). Therefore, we determined in vitro chemosensitivity to daunorubicin, doxorubicin, mitoxantrone, 6-thioguanine, etoposide, and cytosine arabinoside (Ara-C) in childhood ANLL using the colorimetric MTT assay. The 4-day MTT assay was successfully performed in 62/73 samples obtained from 53 children with ANLL. We obtained comparable results from bone marrow or peripheral blood samples, and from fresh or cryopreserved samples. In vitro chemosensitivity was not related to clinical features such as sex, age, white blood cell count, or FAB-types. The group of poor responders to chemotherapy was median 3-fold more resistant to Ara-C than the group of good responders, but identification of a threshold for Ara-C sensitivity predictive for individual responses was limited due to the great overlap of in vitro chemosensitivities between both groups. Children with relapsed ANLL were in vitro median 3-fold more resistant to Ara-C than the initial ANLL group. No significant differences for the other drugs were observed with respect to clinical response or disease status. These results suggest that in vitro resistance to Ara-C plays an important role in chemotherapy failures in childhood ANLL, but larger studies are necessary to establish the predictive value of Ara-C sensitivity assessed with the MTT assay.
Leukemia 1995 Nov
PMID:In vitro chemosensitivity assessed with the MTT assay in childhood acute non-lymphoblastic leukemia. 747 76

Previously, we showed that in vitro resistance to daunorubicin (DNR) at initial diagnosis was related to a poor long-term clinical outcome in childhood acute lymphoblastic leukemia (ALL), and that cells of relapsed ALL were in vitro more resistant to DNR than cells of untreated ALL. Topoisomerase II (Topo II) is an intracellular target for anthracyclines and epipodophyllotoxins. Decreased levels and/or activity of Topo II have been associated with multidrug resistance in cell lines. We investigated Topo II alpha gene expression in fresh leukemic samples from 19 children with untreated and 14 children with relapsed ALL using a sensitive RNase protection assay. The in vitro cytotoxicity of the Topo II inhibitors DNA and teniposide (VM26) was measured using the MTT assay, and the cell cycle distribution of leukemic samples was analyzed by DNA flow cytometry. Results showed that (1) relapsed ALL samples were more resistant to DNR, but not to VM26 compared to untreated samples; (2) large interpatient variations existed in both Topo II alpha gene expression and in vitro cytotoxicity results; (3) Topo II alpha gene expression was detectable in 29/33 childhood ALL samples with a median expression of 5% the level of a relatively chemosensitive human small cell lung cancer cell line; (4) Topo II alpha gene expression did not differ between untreated and relapsed ALL; (5) Topo II alpha gene expression was positively correlated with the percentage of ALL cells in S- and G2M-phase, but not with the in vitro cytotoxicity of the drugs tested. In conclusion, resistance to DNR in childhood ALL can not be explained by decreased levels of Topo II alpha gene expression, but additional Topo II activity studies in fresh leukemia samples may need further exploration.
Leukemia 1995 Oct
PMID:Topoisomerase II alpha gene expression in childhood acute lymphoblastic leukemia. 756 5

The prognosis of acute lymphoblastic leukaemia (ALL) in adults is poor compared with children in terms of complete remission (CR) and leukaemia-free survival. In children in vitro resistance of leukaemic cells to various cytotoxic agents is an independent poor prognostic marker, but the relevance of in vitro drug resistance in adults to poor prognosis has not been described. Lymphoblasts from 16 adults and 32 children with ALL at initial presentation were assayed for in vitro drug sensitivity in a short-term culture system using the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) as an indicator of cell viability. The following drugs were tested: prednisolone, daunorubicin, mitozantrone, etoposide, melphalan and 6-thioguanine. At initial presentation, lymphoblasts from adults demonstrated a significantly higher degree of in vitro resistance to prednisolone than those from children (P < 0.01). Glucocorticoid resistance may be a fundamental difference between adult and childhood ALL which may underlie different biological aspects and also explain the difference in prognosis. Lymphoblasts from adults who achieved CR were more sensitive in vitro to prednisolone (P = 0.07), daunorubicin (P < 0.05), mitozantrone (P < 0.01) and melphalan (P < 0.05) than cells from those who did not. The MTT assay can predict response to induction chemotherapy in adults and therefore discriminate between standard- and high-risk patients. The assay, however, is not suitable for selection of the most effective agent for treatment because of in vitro cross-resistance of lymphoblasts to various drugs tested.
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PMID:Corticosteroid resistance is increased in lymphoblasts from adults compared with children: preliminary results of in vitro drug sensitivity study in adults with acute lymphoblastic leukaemia. 757 60

Cultured cells of Tropaeolum majus produce significant amounts of benzyl glucosinolate which, through enzymatic hydrolysis, results in the production of benzyl isothiocyanate (BITC). This study reports on the in vitro anticancer properties of BITC against a variety of human and murine tumor cell lines by four independent methods; SRB, MTT, cell counting, and clonogenic assays. Regardless of the assay used, BITC showed promising cytotoxicity in the low micromolar range (0.86 to 9.4 microM) against four human ovarian carcinoma cell lines (SKOV-3, 41-M, CHl, CHlcisR), a human lung tumor (H-69), a murine leukemia (L-1210), and a murine plasmacytoma (PC6/sens). The L1210 cells were most sensitive. BITC administered to mice bearing the ADJ/PC6 plasmacytoma subcutaneous tumor showed toxic effects at a dose of 200 mg/kg (within 24 h of drug administration) but no reduction in tumor mass. However, the growth inhibitory properties of BITC against a range of tumor cell types warrant further in vivo anti-tumor evaluation as well as its biotechnological production.
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PMID:In vitro and in vivo antitumor activity of benzyl isothiocyanate: a natural product from Tropaeolum majus. 761 65

A panel of 25 different lipid agents was evaluated for in vitro activity against HT29 human colon carcinoma and HL60 promyelocytic leukaemia cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The structure-activity relationships seen with this series, including those for four sets of positional or stereoisomers, indicate that specific receptor proteins are unlikely as targets for anti-tumour lipid (ATL) action. Additional data confirm the lack of involvement of the platelet-activating factor receptor in particular and suggest that metabolic stability is a most important determinant of ATL activity. More detailed studies, with 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET18-OCH3) and (+/-)-2-(Hydroxy[tetrahydro-2-(octadecyloxy)methylfuran-2- yl]methoxyphosphinyloxy)-N,N,N,-trimethylethaniminium hydroxide (SRI 62-834), suggest three different modes of activity, depending on drug concentration and exposure time. Low doses of up to 5 microM in standard serum-containing medium cause population growth arrest after prolonged exposure. Growth arrest was associated with a leaky G2/M block as determined by flow cytometry. These effects are reversible. Intermediate concentrations (5-40 microM) were cytotoxic, causing a net reduction in cell numbers after 2-3 days. At even higher concentrations, all lipids caused rapid, direct membrane lysis. When the clonogenic assay was used to assess the effects of ATLs, most agents reduced colony formation at concentrations above 5 microM. However, some compounds proved stimulatory at nanomolar concentrations, suggesting that they might possess mitogenic properties. These results, particularly those concerning the concentration and time dependence, may be relevant to current clinical trials with ether lipids.
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PMID:Growth arrest vs direct cytotoxicity and the importance of molecular structure for the in vitro anti-tumour activity of ether lipids. 764 Feb 6

Based on the DNA fragmentation profile in gel electrophoresis and the morphological changes in electron microscopy, the induction of apoptotic nuclear changes by mycotoxins and other microbial products, in total 31 chemicals, was investigated in HL-60 human promyelotic leukemia cells, along with the cytotoxicity tests with 3-[4,5-dimethylthiazol-zyl]-2,5-diphenyltetrazolium bromide (MTT) and trypan blue exclusion. Among the chemicals tested, trichothecenes (T-2 toxin, roridin A, nivalenol, deoxynivalenol), certain anthraquinones (luteoskyrin, skyrin, 2-hydroxyemodin), diketopiperazines (emethallicin A, emestrin), isocoumarins (ochratoxin A, citrinin), lactone (penicillic acid), dihydrobisfuran (aflatoxin B1), potassium ionophore (valinomycin), and an inhibitor of interleukin-2 synthesis (cyclosporin A) were positive for the induction of DNA fragmentation. No DNA fragmentation was observed under the present conditions with fumonisin B1, cyclic peptides (cyclochlorotine, phalloidin, microcystin-LR), certain anthraquinones (emodin, chrysophanol, rugulosin), and others (sterigmatocystin, cytochalasin A, griseofulvin, fusaric acid, kojic acid, rubratoxin B, butenolide, wortmannin, FK506, and sphingosine). The apoptotic changes in the cells exposed to T-2 toxin and luteoskyrin were confirmed by electron microscopic observation. Detailed experiments on dose and time dependencies revealed that T-2 toxin induced the apoptosis at 10 ng/ml (= 4 x 10(-8) M) levels within 2-6 hr without significant cytotoxicity evaluated by the dye exclusion and MTT.
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PMID:Induction of apoptosis by T-2 toxin and other natural toxins in HL-60 human promyelotic leukemia cells. 764 21

Gnidimacrin, a diterpene compound, isolated from the methanol extract of Stellera chamaejasme L, showed significant antitumor activities against mouse leukemia P-388 and L-1210 in vivo. At the dosages of 0.02-0.03mg/kg ip, the in increase in life span (ILS) was 70% and 80%, respectively. Gnidimacrin was also active against murine solid tumors in vivo, such as Lewis lung carcinoma, B-16 melanoma and colon cancer 26. It showed ILSs of 40%, 49% and 41% at the dosages of 0.01-0.02mg/kg ip, respectively. Gnidimacrin strongly inhibited cell proliferation of human cancer cell lines such as leukemia K562, stomach cancers Kato-III, MKN-28, MKN-45, and mouse L-1210 by the MTT assay and colony forming assay in vitro. The IC50 of gnidimacrin was 0.007-0.00012microgram/ml. It is concluded that gnidimacrin is the principal antitumor element in Stellera chamaejasme L. with strong antitumor activities.
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PMID:[The antitumor activities of gnidimacrin isolated from Stellera chamaejasme L]. 765 81

The decrease in cell viability observed in vitro from the effect of chlorambucil (CLB), fludarabine (FAMP) and 2-chlorodeoxy-adenosine (CDA) on peripheral lymphocytes from 49 untreated CLL patients was investigated by the MTT colorimetric assay. The effects of recombinant-interleukin (r-IL)-2 and alpha-interferon (alpha-IFN) on drug-induced cell death were evaluated. r-IL-2 significantly increased in vitro resistance to CLB, while purine analog cytotoxicity was slightly reduced by the cytokine. The potential in vivo significance of r-IL-2, acting as a survival signal on CLB-induced cell death, is supported by the correlation between the lowest IL-2 serum levels, the highest in vitro sensitivity to CLB and a major clinical response after CLB treatment in six out of eight CLL patients. Using 25 samples, alpha-IFN enabled CLL cells to increase resistance to CLB, CDA and FAMP in 14, eight and seven samples, respectively; conversely, alpha-IFN showed a synergism with both CLB and FAMP in six samples and with CDA in four. These results correlate with immunoenzymatic assay data showing that alpha-IFN either up- or down-regulates tumor necrosis factor and IL-1 levels in supernatants of some CLL samples. Apparently, alpha-IFN plays a dual role in regulating drug-induced cell death, while IL-2 seems to solely favor cell survival in CLL.
Leukemia 1995 Sep
PMID:Modulation of purine analogs- and chlorambucil-induced cytotoxicity by alpha-interferon and interleukin-2 in chronic lymphocytic leukemia. 765 11

The MTT assay, a colorimetric assay, is found to be suitable for chemosensitivity testing. Recently, it has been suggested that hematopoietic growth factors (HGF) may enhance the effects of cytostatic drugs in acute myeloid leukemia (AML). We therefore studied the effects of granulocyte colony-stimulating factor (G-CSF), interleukin 3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF) combined with cytosine arabinoside (Ara-C), daunorubicin (DNR), mitoxantrone (MXT), or etoposide (VP-16) by using the MTT assay. The results were compared with in vitro clonogenic assays. Briefly, AML cells of nine patients were incubated in the presence or absence of G-CSF, IL-3, or GM-CSF under serum-free conditions for 24 hours. Next, for the MTT assay, Ara-C (final dilution range: 0.0024-240 micrograms/ml), DNR (final dilution range: 0.05-3.2 micrograms/ml), MXT (final dilution range: 0.05-3.2 micrograms/ml), or VP-16 (final dilution range: 0.1-100 micrograms/ml) were added and incubated for 48 hours. Cell survival was determined and IC75 values (75% reduction as compared to control cultures) were calculated. For clonogenic assays, the three lowest drug concentrations were used. After 48 hours, the clonogenic response was determined in serum-free, semi-solid cultures with G-CSF, IL-3, or GM-CSF. The results obtained by the MTT assay showed no significant enhancement of cytotoxicity by HGF on cytostatic drug preincubated cells compared to cytostatic drugs alone. The results obtained by the clonogenic assays showed increased cytotoxicity of Ara-C combined with G-CSF, IL-3, or GM-CSF. The median IC75 values of Ara-C decreased from 0.056 to 0.0168 microgram/ml with G-CSF (p = 0.01), from 0.108 to 0.0168 microgram/ml with IL-3 (p = 0.004) and from 0.12 to 0.0204 microgram/ml for GM-CSF (p = 0.02). Only moderate enhanced cytotoxicity was observed when VP-16 was combined with IL-3 (p = 0.036) or GM-CSF (p = 0.036), but not with G-CSF. No enhanced cytotoxicity of DNR and MXT to clonogenic AML cells was found when these agents were combined with HGF stimulation. The results indicate that the MTT assay underestimates HGF enhanced cytotoxicity of Ara-C or VP-16 to clonogenic cells. Therefore, the assay is not useful for accurately detecting differences of clonogenic response due to the proliferative status of cells. In this paper, the potential explanations for the failure of the MTT assay are discussed.
Leukemia 1993 Oct
PMID:Enhanced chemosensitivity in acute myeloid leukemia by hematopoietic growth factors: a comparison of the MTT assay with a clonogenic assay. 769 94


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