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1.
Isothermal microcalorimetry was used in order to continuously monitor and quantitatively assess the action of two antineoplastic drugs, methotrexate (MTX) and 6-thioguanine (6-TG), on a human T-lymphoma cell line, CCRF-CEM. The results with MTX were compared with data from experiments with a MTX-resistant subline, CEM/MTX. The slope of the power-time curve after drug injection relative to that obtained during unperturbed growth, was used to construct dose-response curves. The normal cell line was characterized by a D50 value (i.e., the dose producing half the maximal response) of 0.05 microM for MTX and 0.38 microM for 6-TG. For the MTX-resistant subline the D50 value was 8 microM of MTX. Comparisons of the continuous power-time curves showed the inhibitory effect of 6-TG to be faster than that of MTX. 相似文献
2.
E. L. Vodovozova N. R. Kuznetsova G. P. Gaenko Jul. G. Molotkovsky 《Russian Journal of Bioorganic Chemistry》2007,33(4):436-438
We have recently synthesized a lipid conjugate of the anticancer agent methotrexate (MTX-DG) and showed that the conjugate is quantitatively included in the lipid bilayer of liposomes prepared by a standard extrusion technique from an 8:1:1 (mol) egg phosphatidylcholine-yeast phosphatidylinositol-MTX-DG mixture. Both the size of liposomes (126 ± 30 nm) and the MTX-DG concentration (4.4 mM) are relevant for systemic injections in mammals. The liposomal formulation of MTX-DG was shown to overcome the resistance of tumor cells in vitro to methotrexate: the cytotoxic activities (IC50) of MTX in cultures of the human T-lymphoblastic leukemia cell line CEM-CCRF and the MTX-resistant subline CEM/MTX were 0.075±0.005 and 16.4±4.9 μM, respectively, while, in the case of liposomes loaded with MTX-DG, the IC50 values were much closer: 0.77±0.06 and 3.8±1.9 μM. 相似文献
3.
Terry L. Riss Betty H. Stewart David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1989,25(2):127-135
Summary The growth of GH4C1, GH3, GH1, and GH3C15 rat pituitary tumor cell lines was studied in a serum-free medium (designated TRM-1) formulated with 1∶1 (vol/vol) mixture
of Ham's F12 nutrient mixture and Dulbecco's modified Eagle's medium (F12-DME) containing 15 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), 50 μg/ml gentamicin supplemented with 10 μg/ml bovine insulin,
10 μg/ml human transferrin (Tf), 10 ng/ml selenous acid, 10 nM 3,5,3′-triiodothyronine (T3), 50 μM ethanolamine (Etn), and 500 μg/ml bovine serum albumin. Of the lines evaluated, only the GH1 failed to grow in TRM-1. Passage of the GH4C1 and GH3 lines from serum-containing medium into TRM-1 caused an initial selection resulting in cells that grew progressively at higher
rates and finally were maintained indefinitely in TRM-1. These populations showed a requirement for supraphysiologic concentrations
of T3 (1.0 to 10 nM). After adaptation of the GH4C1 line in TRM-1 for ≤20 generations, removal of components gave a less complex mixture containing 15 mM HEPES, 50 μ/ml gentamicin, 10 μg/ml Tf, 10 nM T3, and 50 μM Etn (designated TRM-2) that supported serial passage of the cells. Under these conditions, thyroid hormone dependence was
lost progressively. When T3 was removed from TRM-2 adapted cells, a third population was selected that no longer required thyroid hormones and was only
slightly stimulated by T3. These studies demonstrated that the combination of serum-containing and serum-free conditions can be used to select pituitary
cell populations that a) required both serum-factor(s) and T3 for optimum growth, b) required supraphysiologic concentrations of T3 without serum proteins other than Tf and albumin, and c) were completely autonomous in that they proliferated in medium supplemented
only with Tf and nutrients without necessity of other serum factor(s) or T3.
This work was supported by grants CA-26617 and CA-38024 from the National Cancer Institute, Bethesda, MD, American Cancer
Society grant BC-255, and grant 2225 from the Council for Tobacco Research, Inc., USA. 相似文献
4.
Terry L. Riss' David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1989,25(2):136-142
Summary The effect of 17β-estradiol (E2) on growth of GH4C1 rat pituitary tumor cells was investigated under serum-free conditions and with medium containing charcoal-extracted serum.
Serum-free TRM-1 medium was a 1∶1 (vol/vol) mixture of F12-DME supplemented with 50 μg/ml gentamicin, 15 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, 10 μg/ml insulin, 10 μg/ml transferrin, 10 ng/ml selenous acid, 10 nM 3,5,3′-triiodothyronine (T3), 50 μM ethanolamine, and 500 μg/ml bovine serum albumin. The cells grew continuously in TRM-1 but were E2 responsive only when growth was retarded by reducing the T3 concentration to 10 pM (TRM-MOD). Addition of 1 to 10 nM E2 to TRM-MOD increased growth by 0.3 to 0.9 cell population doublings over controls in 9 d. By using medium supplemented with
charcoal-extracted sera, basal growth became 1 to 1.5 cell population doublings in 9 d. Addition of 0.1 pM E2 to medium containing charcoal-extracted serum caused a significant increase in cell number whereas pM-nM concentrations stimulated 200 to 570% increases over controls. The effect of steroid hormone was the same in phenol-red-containing
and indicator-free medium. The data presented confirm that the major requirements for demonstration of estrogenic effects
in culture were optimum concentrations of thyroid hormones and the presence of yet-to-be-characterized serum factors.
This work was supported by National Cancer Institute (Bethesda, MD) grants CA-26617 and CA-38024, American Cancer Society
grant BC-255, and grant 2225 from The Council for Tobacco Research, U.S.A., Inc. 相似文献
5.
Vegetable soybeam germplasm was screened for its tolerance to 0, 50 and 100 μM Al in solution culture. Plants were inoculated with prescreened acid-Al tolerantBradyrhizobium japonicum strain USDA 110 and a localRhizobium isolate SM867. Aluminum concentrations of 0, 50, and 100 μM affected the root lengths of all germplasm lines in the first few weeks of their growth. At 100 μM, the plants had severely stunted roots throughout the growing period of 35 days, but at 50 μM the initial stunting of the roots was overcome after the third week of growth, and there were no significant differences
between the root lengths of these plants and of the controls. The appearance of the first nodule was delayed for 2–3 and 4–5
days at 50 μM and 100 μM Al, respectively. There was a significant reduction in nodule numbers and acetylene reduction activity (ARA) at 100 μM Al. At 50 μM Al, even though the number of nodules was decreased significantly, nodules were larger in size, so there was no significant
reduction in nodule fresh weight and ARA. No significant differences in nitrogen fixing abilities of the soybean lines were
observed between the twoRhizobium strains. Germplasm line Kahala showed the greatest tolerance to 50 μM Al, and Kahala, Kim and Wolverine tolerated 100 μM Al better than other germplasm lines. 相似文献
6.
Several cell lines of Nicotiana plumbaginifolia resistant tomethotrexate (MTX) were isolated upon gradual elevation of theMTX concentration in the growth medium. One of the MTX-resistantcell lines, NP-19, acquired resistance to 10 mmol m3MTX, that is, at least 50-fold higher than the lethal dose forthe wild-type cell suspension. Its resistance was stably maintainedupon prolonged withdrawal of the drug. The acquisition of resistancewas accompanied by severe deterioration of regeneration potential.Regenerated shoots still manifested resistance to 50 mmol m3.MTX-resistant colonies and tiny shoots were recovered followingasymmetric fusion between -irradiated NP-19 protoplasts andN. plumbaginifolia leaf mesophyll-derived protoplasts on a mediumcontaining 10 mmol m3 MTX. The development of the shootsderived both from NP-19 calli and following somatic fusion wasarrested at the stage of 68 leaves. No difference wasfound in uptake of 3H-MTX between cell suspension of NP-19 andthe parental cell line. A 30-fold increase in binding of 3H-MTXto protein extract was found in cell line NP-19, suggestingdifferential capacity of MTX binding as a mechanism involvedin the MTX resistance of this cell line. Since differentiatedorgans seem more sensitive to MTX than undifferentiated tissues,this cell line is a promising source for a gene(s) conferringenhanced MTX-tolerance both in non-differentiated and differentiatedtissues. Key words: Methotrexate resistance, MTX-binding capacity, MTX uptake, tobacco cell culture 相似文献
7.
William J. Mc Carthy Deborah Mc Kedy 《In vitro cellular & developmental biology. Plant》1990,26(8):824-828
Summary Cultivation of aSpodoptera exigua cloned cell line (SE-UCR-1A) for 8 to 9 mo. in a medium containing increasing amounts of bromodeoxyuridine (BUdr) resulted
in the selection of a BUdr-resistant subline unable to grow in TNMFH medium supplemented with HAT (hypoxanthine, 10−4
M; aminopterin, 10−7
M; thymidine, 10−3
M). Subsequent assay of this subline revealed an absence of thymidine kinase (TK) activity. The specific activity of the wild-type
(wt) cells was 878±192 counts per min (cpm)/μg supernatant protein compared to 9 cpm/μg for the BUdr-resistant, HAT-sensitive
subline. In addition the wt activity was inhibited >90% by addition of BUdr to the assay, indicating that the activity is
predominantly due to TK and not to a nonspecific nucleoside phosphotransferase. The morphology of the TK-deficient (−) cells
was indistinguishable from that of wt cells. The doubling time for wt cells in TNMFH was 16 h; however, in TNMFH-HAT it was
36 h. In comparison the TK(−) cells in TNMFH had a doubling time of 61 h. Cultivation of TK(−) cells in nonselective TNMFH
for 14 mo. to date has not changed the TK(−) characteristic of the subline.
The host-cell TK was not required for development of progeny virus fromAutographa californica NPV inoculum. Although similar numbers of cells were infected (80 to 90%) in the wt and TK(−) lines and extracellular virus
was generated at similar rates to similar titers in both media, the initial appearance of virus in the medium of TK(−) cell
was delayed 10 to 20 h compared to wt cells. In addition, polyhedra appearance was similarly delayed in TK(−) cells and only
20 to 25% of the cells contained >10 polyhedra per cell compared to 75 to 90% for wt cells. Also, during infection of wt cells,
specific activity of TK increased twofold peaking at 20 to 30 h postinfection, yet there was no stimulation of TK activity
in infected TK(−) cells. 相似文献
8.
Doris Marko Konstantinos Romanakis Heinrich Zankl Gerhard Fürstenberger Brigitte Steinbauer Gerhard Eisenbrand 《Cell biochemistry and biophysics》1998,28(2-3):75-101
In order to study potential changes in phosphodiesterase (PDE) activity associated with malignant transformation, normal primary
keratinocytes and cells corresponding to different stages of epidermal tumor development in mouse skin were analyzed with
respect to their 3′,5′-cyclic adenosine monophosphate (cAMP) hydrolyzing activity. Expression of cAMP-specific PDE-4, intracellular
cAMP content, and the sensitivity to the growth inhibitory effect of the PDE-4-specific inhibitor 7-benzylamino-6-chloro-2
piperazino-4-pyrrolidino-pteridine (DC-TA-46) were studied in the two papilloma cell lines, MSCP6 and 308, and in the highly
malignant carcinoma cell line CarB. No significant difference in soluble PDE activity and in intracellular cAMP was found
in the two papilloma cell lines when compared to primary keratinocytes. In contrast, the spindle-cell carcinoma cell line
CarB exhibited significantly higher PDE activity, concomitant with the lowest cAMP level. In all cell lines and also in the
primary keratinocytes, rolipram-sensitive PDE-4 activity accounted for the major cAMP-hydrolyzing activity. In primary keratinocytes
and in MSCP6 cells, the PDE-4 inhibitor DC-TA-46 induced at best marginal growth inhibition, whereas cell growth of 308 cells
was markedly affected at concentrations >2 μM. The carcinoma cell line CarB showed the highest sensitivity to DC-TA-46 (IC50=0.8±0.3 μM). Treatment of CarB cells with DC-TA-46 strongly inhibits intracellular PDE activity, resulting in a marked and long-lasting
rise of cAMP. After 24 h of treatment, arrest in the G0/G1 phase of the cell cycle is induced. Treatment with concentrations >2 μM of this highly effective PDE inhibitor results in induction of apoptotic cell death, as detected by fluorescence microscopy,
flow cytometry, and ELISA-based determination of fragmented DNA in intact cells. 相似文献
9.
Gerald Audesirk David Shugarts Gina Nelson Julie Przekwas 《In vitro cellular & developmental biology. Plant》1989,25(12):1121-1128
Summary Neurons from brains of chick embryos and pond snails (Lymnaea stagnalis) were cultured for 3 to 4 d in the presence of no toxins, inorganic lead (PbCl2), or organic lead (trielthyl lead chloride). In chick neurons, inorganic lead reduced the percentage of cells that grew neurites
(IC50=270μM total lead, approximately 70 nM free Pb2+) but did not reduce the number of neurites per cell or the mean neurite length. Triethyl lead reduced the percentage of cells
that grew neuites (IC50=0.24 μM) and the mean neurite length (extrapolated IC50=3.6 μM) but did not reduce the number of neurites per cell. InLymnaea neurons, inorganic lead reduced the percentage of cells that grew neurites (IC50=13 μM total lead; approximately 10 nM free Pb2+). Triethyl lead reduced the percentage of cells that grew neurites (IC50=0.4 μM) and exerted significant toxicity at 0.2 μM. The two forms of lead affected neurite growth in qualitatively different ways, which suggests that their mechansms of action
are different.
These experiments were supported by grants from the Environmental Protection Agency, Washington, DC, and the National Institutes
of Environmental Health Science, Research Triangle Park, NC. 相似文献
10.
Zinc, cadmium, and copper are known to interact in many transport processes, but the mechanism of inhibition is widely debated,
being either competitive or noncompetitive according to the experimental model employed. We investigated the mechanisms of
inhibition of zinc transport by cadmium and copper using renal proximal cells isolated from rabbit kidney. Initial rates of65Zn uptake were assessed after 0.5 min of incubation. The kinetics parameters of zinc uptake obtained at 20°C were a Jmax of 208.0±8.4 pmol· min−1·(mg protein)−1, aK
m of 15.0±1.5 μM and an unsaturable constant of 0.259±0.104 (n=8). Cadmium at 15 μM competitively inhibited zinc uptake. In the presence of 50 μM cadmium, or copper at both 15 and 50 μM, there was evidence of noncompetitive inhibition. These data suggest that zinc and cadmium enter renal proximal cells via
a common, saturable, carrier-mediated process. The mechanisms of the noncompetitive inhibition observed at higher concentrations
of cadmium or with copper require further investigation, but may involve a toxic effect on the cytoskeleton. 相似文献
11.
Cerovic A Miletic I Sobajic S Blagojevic D Radusinovic M El-Sohemy A 《Biological trace element research》2007,116(1):61-71
Zinc is an important mineral that is required for normal bone development. However, the direct effects of zinc on the mineralization
of bone cells of human origin are not clear. The objective of this study was to determine the effects of zinc on the differentiation
of SaOS-2 human osteoblast-like cells and the formation of mineralized bone nodules. Cells were cultured for 8 d and then
transferred to zinc-free medium and treated with varying concentrations (0–50 μM) of zinc. Alkaline phosphatase (ALP) activity was used as a measure of osteoblast differentiation, and bone nodules were
detected by von Kossa staining. After 4, 6, and 8 d of treatment, zinc increased ALP activity at 1 and 10 μM, but decreased activity at 50 μM. After 9 d of treatment, zinc increased both the number and area of mineralized bone nodules at low concentrations (1 and
10 μM), but decreased both at higher concentrations (25 and 50 μM). These findings demonstrate that zinc has biphasic effects on the differentiation and mineralization of human osteoblast-like
cells. 相似文献
12.
Summary Methyl jasmonate (MeJA) interacted significantly with both indole-3-acetic acid (IAA) and 6-benzylaminopurine (BA) to influence
cell growth of cultured Onosma paniculatum cells. Cell growth decreased with increasing concentrations of MeJA from 0.004–4.45 μM with or without IAA and BA. The same concentrations of MeJA (0–4.45 μM) increased the cell growth with IAA and BA, when administered to the cultured cells in M9 medium. This was found to enhance the production of shikonin. The optimum time for MeJA addition for enhanced shikonin formation
was 4 d after cell inoculation in M9 medium. Furthermore, shikonin formation was affected significantly by both MeJA/IAA and MeJA/BA combinations. Shikonin content
was enhanced by increasing MeJA concentrations with IAA concentrations in the range of 0–28 μM and with BA concentrations in the range of 0–44.38 μM in MeJA/BA experiments, respectively. The optimal combination of MeJA and IAA was 4.45 μM and 0.28 μM, while MeJA and BA concentrations of 4.45 μM and 2.22 μM were optimal for shikonin formation. The result also showed that MeJA increased phenylalanine ammonia-lyase (PAL) and p-hydroxybenzoic acid-geranyltransferase (PHB-geranyltransferase) activites during the course of shikonin formation, but decreased
the activity of PHB-O-glucosyltransferase within 9 d after inoculation. These results suggest that enhanced shikonin formation in cultured Onosma paniculatum cells induced by MeJA involves regulation of the key enzyme activities. 相似文献
13.
Cells resistant to methotrexate (MTX) were obtained from two established cell lines of D. melanogaster and a karyological analysis was performed. No conspicuous changes in the frequencies of cell types were observed in MTX-resistant (MTXR) subline 0.57, as compared with the original line, whose cells were mostly near-tetraploid. On the contrary, altered karyotypes were frequently noticed in the C1 82 MTXR subline, as compared with the original line, whose cells were mostly diploid. The C1 82 MTXR subline was characterized by mostly tetraploid cells and by the presence of chromosome fragments (in 48% of them). The mitotic segregation suggests the presence of a centromere in these fragments and the fluorescence pattern, after quinacrine staining, suggests that they may be derivatives of the X chromosome. 相似文献
14.
We compared the effects of four quaternary benzo[c]phenanthridine alkaloids – chelerythrine, chelilutine, sanguinarine, and sanguilutine – and two quaternary protoberberine
alkaloids – berberine and coptisine – on the human cell line HeLa (cervix carcinoma cells) and the yeastsSaccharomyces cerevisiae andSchizosaccharomyces japonicus var. versatilis. The ability of alkaloids to display primary fluorescence, allowed us to record their dynamics and localization in cells.
Cytotoxic, anti-microtubular, and anti-actin effects in living cells were studied. In the yeasts, neither microtubules nor
cell growth was seriously affected even at the alkaloid concentration of 100 μg/ml. The HeLa cells, however, responded to
the toxic effect of alkaloids at concentrations ranging from 1 to 50 μg/ml. IC50 values for individual alkaloids were: sanguinarine IC50 = 0.8 μg/ml, sanguilutine IC50 = 8.3 μg/ml, chelerythrine IC50 = 6.2 μg/ml, chelilutine IC50 = 5.2 μg/ml, coptisine IC50 = 2.6 μg/ml and berberine IC50 >10.0 μg/ml. In living cells, sanguinarine produced a decrease in microtubule numbers, particularly at the cell periphery,
at a concentration of 0.1 μg/ml. The other alkaloids showed a similar effect but at higher concentrations (5–50 μg/ml). The
strongest effects of sanguinarine were explained as a consequence of its easy penetration through the cell membrane owing
to nonpolar pseudobase formation and to a high degree of molecular planarity.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
Robert A. Harper B. Allen Flaxman 《In vitro cellular & developmental biology. Plant》1981,17(5):393-396
Summary Primary cell cultures of normal rabbit epidermal cells (keratinocytes) were established without the use of enzymatic techniques.
Six experiments were carried out on cells from six different rabbits. When these cells were exposed to methotrexate (MTX)
for 24 h at 1 μg/ml, proliferation, as measured by cells entering mitosis, was significantly inhibited (P<0.05) in only one experiment. When the dose of MTX was elevated to 100 μg/ml, only two experiments showed significant inhibition
of mitosis. This minimal inhibition of mitosis by MTX was contrasted by the dramatic inhibitory effect of this antimetabolite
on DNA synthesis. At 1 μg/ml MTX for 24 h, DNA synthesis, as measured by [3H]deoxyuridine uptake, was inhibited >95%. We can conclude that under certain conditions, the rabbit keratinocyte may represent
a normal cell type that is inherently resistant to the antiproliferative effects of methotrexate.
The research was supported by National Cancer Institute Grant CA 11536. 相似文献
16.
The effects of low concentrations of aluminium on the growth and uptake of nitrate-N by white clover 总被引:1,自引:0,他引:1
Summary The effects of aluminium (Al3+) at concentrations of 0, 25, 50 and 100 μM on the growth of white clover, dependent upon N supplied as NO
3
−
, were examined in flowing solution culture. Plants were established with a normal nutrient supply for 7 weeks and then grown
with carefully controlled pH (at 4.5) and P concentrations, and with 0, 25, 50 or 100 μM Al3+ for a further three weeks. There were rapid visual effects (i.e. symptoms of P deficiency and reduction in root extension) and the dry weights of shoots and roots were reduced at 50 and
100 μM. Less than 10% of Al absorbed from solution was transported to the shoots. The uptake of P, and its transport between roots
and shoots, were reduced in plants grown with Al. The uptake of NO
3
−
stopped immediately after the introduction of 50 or 100 μM Al, and was significantly reduced at 25 μM after three weeks.
During a second phase of the experiment, plants previously grown at 0, 25, 50 and 100 μM Al, were grown for a further 2 weeks either with NO
3
−
(with and without 50 μM Al3+) or without NO
3
−
but with inoculation by Rhizobia (and with or without 50 μM Al3+). The effects of the previous treatments with Al on N uptake were small during the second phase, but uptake by all plants
was restricted when Al was present. Inoculation did not result in nodulation in the second phase when Al3+ was present in the solution, but Al already in the plant from the first phase did not prevent nodulation in the absence of
Al during the second phase. 相似文献
17.
Suleiman A. Suleiman Jeffrey B. Stevens 《In vitro cellular & developmental biology. Plant》1987,23(5):332-338
Summary Cell viability, cytochrome P-450 content, cell respiration, and lipid peroxidation were all investigated as a function of
oxygen tension in adult rat hepatocytes in short-term culture (less than 9 h). The various oxygen tensions used in this study
were obtained by equilibrating culture medium with air, air + nitrogen, or air + oxygen. Cell viability, as assessed by trypan
blue exclusion, was significantly greater at all time points tested when hepatocytes were cultured in Ham's F12 medium containing
132 μM O2, as compared to medium equilibrated with air (220 μM O2) or air + oxygen (298 μM O2). Cells cultured in 220 μM O2 (air) also exhibited a gradual loss of cytochrome P-450, so that by 9 h of incubation less than 60% of the active material
remained. This loss of P-450 was minimized when cells were cultured in 163 μM O2 and abolished when cells were cultured in 132 μM O2. The 132 μM O2 exposure conditions also maintained cell respiration at the 1 h incubation values, whereas there was a continuous loss in
cell respiration over time when the cells were cultured in either 220 μM O2 (air) or 298 μM O2 (air:O2). These cytotoxicity findings may be related to oxidative cell damage inasmuch as it was additionally demonstrated that lipid
peroxidation (as measured by malondieldehyde equivalents) was consistantly lower in hepatocytes cultured in air:N2 as compared to air or air:O2. These results suggest that hepatocyte culture in low oxygen tension improves not only cell viability but also maintains
other functional characteristics of the cell.
This work was supported by a Biomedical Research Support Grant S-S07-RR 05448 awarded to the University of Minnesota School
of Public Health by the Biomedical Research Grant Program, Division of Research and Resources, National Institutes of Health,
Bethesda, MD. 相似文献
18.
N. R. Kuznetsova G. P. Gaenko S. V. Haidukov N. V. Bovin E. L. Vodovozova 《Russian Journal of Bioorganic Chemistry》2009,35(4):490-496
The efficiency of the chemotherapeutic agent methotrexate (MTX) in cancer treatment is limited by the frequent development of the drug resistance of tumor cells. We had previously shown in vitro using human acute leukemia cells with various sensitivity to MTX (T-lymphoblastic CCRF-CEM line and resistant CEM/MTX subline) that MTX incorporation into liposomes in the form of a lipophilic prodrug, diglyceride conjugate (MTX-DG), allows for the overcoming of cell resistance due to the impaired active transmembrane transport. In this work, we have studied the profile of binding with carbohydrates of the cell lines mentioned using carbohydrate fluorescent probes (poly(acryl amide) conjugates). Lipophilic conjugates of tetrasaccharide SiaLeX, 6′-HSO3LacNAc, and also inactive pentaol for incorporation into liposomes, have been synthesized. The cytotoxicity of MTX-DG liposomes equipped with the SiaLeX ligand toward the sensitive CCRF-CEM cell culture was demonstrated to be 3.5 times higher than that of MTX-DG liposomes bearing the control inactive pentaol. The activity of MTX liposomes bearing 6′-HSO3LacNAc toward resistant CEM/MTX was 1.6-fold increased. The use of carbohydrate ligands as molecular addresses for drug-carrying liposomes as a potential method of treating heterogeneous tumor tissue is discussed. 相似文献
19.
Tarun Ghose Soldano Ferrone A. Huntley Blair Yaroslav Kralovec Massimo Temponi Mandip Singh Moll Mammen 《Cancer immunology, immunotherapy : CII》1991,34(2):90-96
Summary Intravenous injections into nude mice of 5 mg/kg methotrexate (MTX) linked to the antibody to human high molecular weight-melanoma associated antigen (HMW-MAA), monoclonal antibody (mAb) 225.28, an IgG2a, on days 1, 4, 7, 10 and 14, starting 24 h after subcutaneous inoculation of 2 × 106 cultured human M21 melanoma cells inhibited mean tumor volume by 90% on day 14 and by 65% on day 50 after the beginning of the treatment. Injections of equimolar amounts of free MTX and MTX linked to normal mouse IgG or to an isotypematched myeloma protein did not inhibit tumor growth significantly. MTX linked to mAb 225.28 did not inhibit the xenograft of a subline of human melanoma cell line M21 without detectable expression of HMW-MAA. In a clonogenic assay, the MTX-225.28 conjugate was three times more potent in inhibiting the growth of M21 melanoma cells than free MTX, but did not inhibit the growth of kidney carcinoma cells Caki-1, which do not express high-M
r MAA. In contrast, MTX linked to the mAb DAL K29, reacting with kidney carcinoma cells Caki-1, inhibited their growth but did not affect that of melanoma cells. M21 melanoma cells isolated from the residual tumor of a mouse treated with the MTX-225.28 conjugate did not differ in their reactivity with mAb 225.28 and in their sensitivity to MTX when compared with M21 cells from an untreated mouse. 相似文献
20.
R.Douglas Armstrong Raul Vera Paul Snyder Ed Cadman 《Biochemical and biophysical research communications》1982,109(2):595-601
Studies were completed to characterize the cytotoxic and biochemical interaction of methotrexate (MTX) and 6-thioguanine (6-TG). Pretreatment of L1210 leukemia cells for 3 hr with MTX substantially enhanced the cytotoxicity of 6-TG. The LD90 of 6-TG in cells pretreated with 1μM MTX was 0.9pM, compared to an LD90 of 800 pM when the two drugs were given concurrently and an LD90 of 30 pM resulted with 6-TG alone. HPLC analysis of intracellular metabolites demonstrated an increased conversion of 6-TG to 6-TG-nucleotides in cells pretreated with MTX. A marked enhancement of 6-TG incorporation into RNA also was noted (MTX→6-TG: 350 fmol/μg RNA vs 6-TG: 98 fmol/μg RNA). However, there was a suppression of 6-TG incorporation into DNA when cells were pretreated with MTX (MTX→6-TG: 170 fmol/μg DNA vs 6-TG: 690 fmol/μg DNA). These results suggest that: 1) an enhancement of 6-TG antileukemic activity can be obtained with MTX pretreatment, and 2) the enhancement of 6-TG cytotoxicity following MTX exposure is not associated with 6-TG incorporation into DNA, but rather with incorporation of 6-TG into RNA. This drug sequence may be beneficial in the clinical treatment of leukemia. 相似文献