Resistant L1210 Leukemia Research Articles

6- and 7-substituted 2-[2'-(dimethylamino)ethyl]-1,2-dihydro-3H-dibenz[de,h] isoquinoline-1,3-diones: synthesis, nucleophilic displacements, antitumor activity, and quantitative structure-activity relationships.

New 2-[2'-(dimethylamino)ethyl]-3H-dibenz[de,h]isoquinoline-1,3-diones with substituents at the 6- and 7-positions were prepared. Nucleophilic aromatic displacement was a key reaction in the syntheses. Ten of the new compounds were more potent than the unsubstituted compound, azonafide, in a panel of tumor cells including human melanoma and ovarian cancer and murine sensitive and MDR L1210 leukemia. They also were less cardiotoxic in cell culture. Four of these compounds were not cross-resistant with the MDR leukemia, and one of them, 6-ethoxyazonafide, was nearly as potent against solid tumor cells as leukemia cells. These compounds also had good potency against human breast, colon, and lung cancer cells, including doxorubicin and mitoxantrone resistant cell lines. Advantages of the new analogues over azonafide were less in vivo, but 6-ethoxyazonafide was more effective against L1210 leukemia and subcutaneous B16 melanoma in mice. Although correlations of antitumor potency in cells and physicochemical properties of substituents were not found, there were statistically significant correlations of DNA melt transition temperature (delta Tm) with potency in solid tumor cells and sensitive and MDR resistant L1210 leukemia cells for 6-substituted azonafides and with solid tumors for 7-substituted azonafides.

Synthesis, antitumor activity, and chemical properties of silaplatin and related platinum (II) and platinum (IV) complexes derived from beta-silyl amines.

Platinum (II) and platinum (IV) coordination complexes derived from beta-silyl-substituted amines were prepared. The solubility of selected complexes in water and physiological saline was measured, and the effect of the beta-silicon on the reactivity of the complex in aqueous solution was determined by HPLC. The stabilities of selected silyl complexes were compared to the carbon analogues. The cyclic complexes 2a ("silaplatin") and its Pt(IV) analogue, 2b, were very active against L1210 leukemia in vivo. Both the platinum (II) complex 2a and the platinum (IV) complex 2b produced a significant number of cures over the dose range 10-40 mg/kg. The platinum (II) complex 2a, silaplatin, was very active in vivo against an L1210 leukemia subline that was resistant to cisplatin; 2a was also active, when given ip, against ic implanted L1210. The cyclobutanedicarboxylic acid complex 3c was synthesized; this complex was active against both cisplatin sensitive and resistant L1210 leukemia but was less potent than the analogous dichloro compound 2a. The acyclic platinum (II) and platinum (IV) complexes 1a,b were synthesized and unexpectedly found to be inactive in vivo against L1210 leukemia. More lipophilic silaplatin analogues were prepared--Pt(II) complex 2c and Pt(IV) complex 2d have one additional methylene carbon compared to 2a,b, whereas Pt(II) complex 2e and Pt(IV) complex 2f have two additional methylene carbons. Cyclization of the alkyl groups attached to the silicon gave the spiro bicyclic Pt(II) complexes 10a and 11a and the Pt(IV) complexes 10b and 11b.

Methotrexate resistance in an in vivo mouse tumor due to a non-active-site dihydrofolate reductase mutation.

A series of methotrexate (MTX)-resistant L1210 leukemia murine ascites tumors were developed in vivo and analyzed for drug resistance. Three of 20 tumors studied expressed an altered dihydrofolate reductase (DHFR) and each was identical, having a C to T base transition at nucleotide 46 in the DHFR gene as demonstrated by PCR and direct sequencing. This transition results in a Gly to Trp substitution at amino acid 15 of the enzyme. Purified altered enzyme displays significantly lower binding affinity for the antifolates MTX, trimetrexate, edatrexate, and trimethoprim with respective Ki values 165-, 76-, 30-, and 28-fold higher than values obtained for enzyme isolated from parental tumor (wild-type enzyme). Substrate (dihydrofolate) and cofactor (NADPH) binding is also diminished for the mutant enzyme, although to a lesser extent (17.3- and 3.6-fold higher Km, respectively). Gly-15 is highly conserved for all vertebrate species of DHFR but has no known interaction(s), either directly or indirectly, with bound cofactor, substrate, or inhibitor. Protein molecular modeling reveals that the affected residue is 9-12 A away from the enzyme active site and located in a region analogous to the mobile Met-20 loop domain characterized for Escherichia coli DHFR.

Additional nucleotide derivatives of mitosenes. Synthesis and activity against parental and multidrug resistant L1210 leukemia

Cytidine 5'-monophosphate and 5'-ara-CMP conjugates of 2,7-diaminomitosene, with the phosphate groups linked to C-1, were prepared by treating mitomycin C with the appropriate nucleotides. 5'-UMP conjugates were prepared from mitomycin A, 7 (M-83), and 8 (BMY-25282) by similar procedures. A conjugate could not be prepared from mitomycin C and 6-MPRP, but a sulfur-linked derivative was made with 6-MP ribonucleoside. The corresponding 1-hydroxy-2-aminomitosenes were prepared from the parent mitomycin analogues for structure-activity comparisons. All compounds were tested against L1210 murine leukemia in the MTT tetrazolium dye assay. In general, the conjugates were less potent than the parent mitomycins; however 5'-ara-CMP conjugate 14 derived from mitomycin C was more potent than the parent compound or any mitomycin tested except mitomycin A. It also was more potent than ara-C. This result establishes the value of this approach to prodrugs, at least in cell culture. Against a multi-drug-resistant L1210 cell line, all of the conjugates derived from mitomycin C were more potent than the parent compound. 6-Mercaptopurine ribonucleoside conjugate 15 was more active against the resistant cells than it was against the parental cell line.

Dl-1,2-Bis(2-hydroxyphenyl)ethylenediamine]dichloroplatinum(II), a new compound for the therapy of ovarian cancer

The synthesis of diastereoisomeric [1,2-bis(2-hydroxyphenyl)ethylenediamine]dichloroplatinum(II) complexes, DL-3-PtCl2 and meso-3-PtCl2, and their evaluation on the hormone-independent, human MDA-MB231 breast cancer cell line, on the cisplatin-sensitive and -resistant L1210 leukemia cell line, on the cisplatin-resistant human NIH:OVCAR 3 ovarian cancer cell line, on the P-388 leukemia of the mouse and on the cisplatin-sensitive and -resistant Ehrlich ascites tumor of the mouse are described. On all tumor models DL-3-PtCl2 produces a marked inhibitory effect. The diastereoisomer meso-3-PtCl2 is less active and more toxic. It is striking that DL-3-PtCl2 leads to a pronounced inhibition of all cisplatin-resistant tumors. At non-toxic concentrations DL-3-PtCl2 produces cytocidal effects on the NIH:OV-CAR 3 cell line. Therefore DL-3-PtCl2 is of interest for further evaluation for the therapy of ovarian cancer.

Mitomycin C resistant L1210 leukemia cells: association with pleiotropic drug resistance.

A mitomycin C-resistant (MMCR) strain of L1210 mouse leukemia was developed by continuous drug exposure in vitro. MMC concentrations were increased in a stepwise fashion beginning at 0.033 microM and ending at 0.34 microM. This produced a 10-fold resistant cell line over the parental line. Resistance simultaneously developed to anthracene and anthracycline DNA intercalators, to vinca alkaloids and epipodophyllotoxins but not to cisplatin, bleomycin, fluorouracil or ionizing X-rays. MMC resistance was reversed using the membrane-active agent verapamil. The level of non-protein sulfhydryls was increased 2-fold in the MMCR cells. Intracellular uptake of unchanged MMC was reduced by 40% in the MMCR cells. Cytogenetic analyses demonstrated no recognizable clonal chromosomal alterations unique to the resistant subline and no evidence of double minutes or homogeneously staining regions in the DNA. Gel renaturation analysis failed to document the presence of an amplified DNA domain. Southern blotting of parental and MMCR DNA using a cDNA probe (CHP1) for the P-glycoprotein gene also failed to demonstrate amplification or rearrangement of P-glycoprotein-related homologous sequences. However, an Mr 180,000 glycoprotein was detected in the plasma membranes from MMCR cells. This protein also specifically reacted with a monoclonal antibody (C219) to the P-glycoprotein of Ling and co-workers [Kartner et al., Nature, Lond. 316, 820 (1985)]. These results suggest a pleiotropic drug resistance pattern in the MMCR cells, associated with membrane glycoprotein alterations, enhanced non-protein sulfhydryl levels, and reduced MMC accumulation. This is a novel observation for a resistant cell line selected with an alkylating agent.

Decreased cisplatin uptake by resistant L1210 leukemia cells

Cisplatin resistance remains poorly understood compared to other forms of anti-neoplastic drug resistance. In this report radiolabeled cisplatin and rapid separation techniques were used to compare drug uptake by L1210 leukemia cells that are sensitive (K25) or resistant (ZCR9) to cisplatin. Uptake of cisplatin by both cell lines was linear without saturation kinetics up to 100 μM. The resistant ZCR9 cells had 36–60% reduced drug uptake as compared to its sensitive parent line, K25. In contrast, there was no difference in the rate of efflux. We conclude that a decreased rate of uptake is one possible mechanism of cellular cisplatin resistance.

ChemInform Abstract: Antitumor Complexes of Platinum with Carrier Molecules. Part 3. Cytotoxicity of Some Platinum Amino Acid Complexes Against Cisplatin‐sensitive and Resistant L1210 Leukemia Cells

Chemischer InformationsdienstVolume 17, Issue 51 Organoelement Compounds ChemInform Abstract: Antitumor Complexes of Platinum with Carrier Molecules. Part 3. Cytotoxicity of Some Platinum Amino Acid Complexes Against Cisplatin-sensitive and Resistant L1210 Leukemia Cells A. COLOMBO, A. COLOMBOSearch for more papers by this authorR. DI GIOIA, R. DI GIOIASearch for more papers by this authorA. PASINI, A. PASINISearch for more papers by this authorT. DASDIA, T. DASDIASearch for more papers by this authorF. ZUNINO, F. ZUNINOSearch for more papers by this author A. COLOMBO, A. COLOMBOSearch for more papers by this authorR. DI GIOIA, R. DI GIOIASearch for more papers by this authorA. PASINI, A. PASINISearch for more papers by this authorT. DASDIA, T. DASDIASearch for more papers by this authorF. ZUNINO, F. ZUNINOSearch for more papers by this author First published: December 23, 1986 https://doi.org/10.1002/chin.198651294Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume17, Issue51December 23, 1986 RelatedInformation

Antitumor complexes of platinum with carrier molecules. 3. Cytotoxicity of some platinum amino acid complexes against cisplatin-sensitive and resistant L1210 leukemia cells

Antitumor complexes of platinum with carrier molecules. 3. Cytotoxicity of some platinum amino acid complexes against cisplatin-sensitive and resistant L1210 leukemia cells

Immunologic Heterogeneity of Dihydrofolate Reductase from Methotrexate Sensitive and Resistant L1210 Leukemia Cells

Dihydrofolate reductase from L1210 leukemia cells which are sensitive and resistant to methotrexate has the same physical and kinetic properties and immunoreactivity with a guinea pig antiserum raised to the enzyme purified from the methotrexate resistant strain. However, a chicken antiserum to dihydrofolate reductase from methotrexate sensitive L1210 cells has greater affinity for the homologous enzyme than for the enzyme from the MTX resistant cells indicating that there is some antigenic difference in these molecules.

Inhibition of dihydrofolate reductase, methotrexate transport, and growth of methotrexate-sensitive and -resistant L1210 leukemia cells in vitro by 5-substituted 2,4- diaminoquinazolines

A series of eighteen 2,4-diaminoquinazoline analogues of folic, isofolic, pteroic and isopteroic acids having various substituents at position 5 was studied. Each compound was evaluated as an inhibitor of L1210 dihydrofolate reductase, methotrexate influx into L1210 leukemia cells, and growth of methotrexate-sensitive and -resistant L1210 cells in vitro. Bridge reversal at positions 9 and 10 reduced the effectiveness of the classical analogues only with regard to the inhibition of the drug-sensitive cells as compared to methotrexate (MTX). Absence of the glutamate moiety adversely affected the potency of the compounds, particularly when coupled with reversal of the 9, 10-bridge. However, the presence of-Cl at position 5 restored significantly the potency of these compounds. The pteroate and isopteroate analogue ethyl esters were generally more effective inhibitors of cell growth than their non-esterified counterparts. Regarding the effects of substituents at position 5, the data suggest that -Cl > -CH 3 > -H for inhibition of methotrexate transport and growth of methotrexate-sensitive L1210 cells. The 5-Cl pteroate analogue and its corresponding ethyl ester were highly effective as growth inhibitors of methotrexate-resistant, transport-defective, L1210 cells in vitro.

Synthesis and antitumor activity of platinum complexes containing neutral and protonated amino-olefin ligands

A series of compounds containing N-substituted allyl amines bound to platinum are reported. Under acidic conditions, compounds of the general formula (protonated amino-olefin)PtCl 3 are formed. Infrared and 1H NMR spectroscopy establish that these complexes contain a protonated nitrogen and that the olefin is coordinated to platinum. Complexes containing neutral allyl amines are apparently dimeric, with bridging ally amine. All of these complexes contain platinum-chloride bonds activated toward hydrolysis, and all were examined for potential antitumor activity. Most of the protonated ligand complexes exhibited significant cytotoxicity against both cis-platinum sensitive and resistant L1210 Leukemia in cell culture. Neutral ligand complexes were, in all cases, less cytotoxic. Preliminary studies in mice demonstrate only marginal activity against L1210 in vivo.

Studies with a 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine (DDMP)-resistant L1210 leukemia cell line without cross-resistance to methotrexate

An L1210 leukemia cell line resistant to 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine (DDMP) (L1210/DDMP) was developed in vivo by treatment of tumor-bearing mice. Resistance to DDMP was confirmed by subsequent in vivo survival experiments and by in vitro dose-response curves. The L1210/DDMP line demonstrated little cross-resistance to another folate analog, methotrexate (MTX). This was confirmed both in vivo, with survival experiments, and in vitro, using dose-response curves. A statistical analysis of the in vivo data confirmed DDMP resistance with lack of MTX cross-resistance. Dihydrofolate reductase (DHFR) activity in the L1210/DDMP/R 5 line was no greater than in the parent cell line (L1210/S). and the K m of DHFR for dihydrofolate was the same in the L1210/DDMP/R 5 and L1210/S lines. The K i for DHFR of the L1210/DDMP/R 5 cell line versus the L1210/S cell line was increased 3.0-fold for MTX and 3.5-fold for DDMP. Total accumulation of [ 14C]DDMP was identical in the two cell lines. The explanation for the lack of MTX cross-resistance in the L1210/DDMP/R 5 line is unknown.

Treatment of localized inoperable neoplasms with intra-arterial infusions of 8-azaguanine.

Treatment of localized inoperable neoplasms with intra-arterial infusions of 8-azaguanine.