Cheryl Santos

Cytotoxic analogues of 2,6-bis(arylidene)cyclohexanones.

A series of 2,6-bis(arylidene)cycloalkanones (1) and related compounds containing one or two substituents at the four position of the cyclohexyl ring were prepared and shown to display cytotoxic activity towards murine P388 and L1210 cells as well as human Molt 4/C8 and CEM T-lymphocytes. In some of the series of compounds, positive correlations were noted between the potencies of the enones and the magnitude of the Hammett sigma values of the aryl substituents. Four representative compounds were cytotoxic to a number of human tumours in vitro, particularly towards colon cancer and leukemic cells. A noteworthy feature of the compounds prepared in this study is that, in general, they were well tolerated when administered to rodents. A number of lead molecules emerged from this investigation as well as guidelines for future expansion of these series of compounds.

Class III β-tubulin is a marker of paclitaxel resistance in carcinomas of unknown primary site

PurposeIn this study, we determine the prevalence and the prognostic value of the class III β-tubulin microtubule protein examined immunohistochemically, in tumors of 40 patients with carcinomas of unknown primary site treated with paclitaxel-based chemotherapy.MethodsImmunohistochemical intensity of staining and percentage of cells were quantified. Clinical characteristics, response to chemotherapy, progression-free survival, and overall survival were assessed for relationships with the expression of class III β-tubulin.ResultsThe response rate was 17.9% (seven partial responses among 39 valuable patients), while eleven patients had a stable disease (28.2%) and 21 patients progressed on therapy (53.8%). Patients with high class III β-tubulin expression were more resistant to taxane-based chemotherapy, defined as progression under treatment, while patient characteristics were not found to be correlated with response to chemotherapy. Patients whose tumors expressed high levels of class III β-tubulin isotype had shorter overall survival, while there was a trend for an association with progression free survival. Multivariate analysis showed that class III β-tubulin expression was independently correlated with progression free survival and overall survival.ConclusionsThese findings suggest that a high level of expression of class III β-tubulin in tumor cells is associated with resistance to paclitaxel and decreased survival in patients with carcinomas of unknown primary receiving paclitaxel-based chemotherapy.

Cytotoxic N-[4-(3-aryl-3-oxo-1-propenyl)phenylcarbonyl]-3,5-bis(phenylmethylene)-4-piperidones and related compounds

A series of 4-carboxychalcones 1 were prepared and coupled to 3,5-bis(phenylmethylene)-4-piperidone (2) giving rise to a novel series of N-[4-(3-aryl-3-oxo-1-propenyl)phenylcarbonyl]-3,5-bis(phenylmethylene)-4-piperidones (3). Molecular simplification of the amides 3 led to the formation of the corresponding N-(3-aryl-1-oxo-2-propenyl)-3,5-bis(phenylmethylene)-4-piperidones (4). A cytotoxic evaluation of the compounds in series 1-4 utilized murine P388 and L1210 cells as well as human Molt 4/C8 and CEM T-lymphocytes. In general, the compounds displayed significant toxicity; the IC(50) values of 54% of the enones were less than 10 microM when all four screens were considered and less than 1 microM for all members of series 3 in the P388 assay. Various correlations were established between the potencies of the compounds in series 1, 3 and 4 and the Hammett sigma, Hansch pi and molecular refractivity constants of the aryl substituents. Several torsion angles and interatomic distances of five representative compounds in series 3 and 4 were determined by X-ray crystallography, some of which contributed to the observed bioactivity. The marked cytotoxicity and lack of murine toxicity of most of the compounds described in this study, as well as their selective toxicity towards different tumour cell lines, revealed that development of the enones 2-4 as novel candidate antineoplastic agents should be pursued.

Cytotoxic 1,3-diarylidene-2-tetralones and related compounds

A number of 1,3-arylidene-2-tetralones 1, 2 and 4 were synthesised and demonstrated cytotoxic activity towards murine P388 and L1210 cells as well as human Molt 4/C8 and CEM T-lymphocytes. In general, the related 1-arylidene-2-tetralones 3 possessed lower potencies in these screens than the compounds in series 1 and 4. Approximately, half of the compounds were evaluated against a panel of human tumour cell lines. In this screen, most of the enones were more cytotoxic than the established anticancer agent melphalan and some demonstrated selective toxicity towards leukemic and colon cancer cells. The modes of action of representative compounds include interfering with the biosyntheses of nucleic acids and proteins as well as altering redox potentials. The compounds were well tolerated when administered intraperiteonally to mice. Thus these novel enones are promising prototypic molecules due to their potent cytotoxic properties and lack of significant murine toxicity.

3,5-bis(phenylmethylene)-1-(N-arylmaleamoyl)-4-piperidones: a novel group of cytotoxic agents.

A series of novel 3,5-bis(phenylmethylene)-1-(N-arylmaleamoyl)-4-piperidones 3 have been synthesized which displayed potent cytotoxicity towards human Molt 4/C8 and CEM T-lymphocytes as well as murine P388 and L1210 leukemic cells. In contrast, the related N-arylmaleamic acids 4 possessed little or no cytotoxicity in these four screens. Molecular modeling revealed certain interplanar and bond angles and interatomic distances which were perceived to contribute to the observed bioactivity as well as providing suggestions for future structural modifications of the piperidones 3. Evaluation of representative compounds in series 3 and 4 on the activity of human N-myristoyltransferase revealed that, at the maximum concentration utilized, namely 250 μM, only weak inhibiting properties were displayed by some of the compounds in series 4. Various members of series 3 and 4 were well tolerated in mice.

Prognostic Significance of Tissue Inhibitor of Metalloproteinase-1 in Breast Cancer

Introduction. Despite advances in breast cancer systemic treatment, new prognostic and predictive factors are still needed. Tissue inhibitor of metalloproteinase-1 (TIMP-1), a physiologic inhibitor of matrix metalloproteinases (MMPs), can act in both pro- and antitumoral effects. As role of TIMP-1 in breast cancer is controversial, we aimed to determine the prognostic significance of TIMP-1 in breast cancer. Methods. A single center-based case-control study was applied. Primary breast cancers from women with early stage disease treated with standard adjuvant therapy were analyzed by gene expression microarrays and immunohistochemistry for TIMP-1. Results. At the optimized cut-point, patients with high TIMP-1 RNA levels had a significantly shorter time to relapse, with a hazard ratio (HR) of 1.64 (P = 0.04), but without significant differences in overall survival (HR 1.29, P = 0.37). Although cytoplasmic overexpression of TIMP-1 protein was not correlated with early relapse (HR 1.0, P = 0.92), there was a tendency for short overall survival in patients with high expression (HR 1.41, P = 0.21). Conclusions. Our data indicate that elevated TIMP-1 RNA levels are independently prognostic for early recurrence, and there is a tendency for association of high cytoplasmic TIMP-1 protein levels with short survival in primary breast cancer.

Cytotoxic 1,4-bis(2-oxo-1-cycloalkylmethylene)benzenes and related compounds.

A series of 1,4-bis(2-oxo-1-cycloalkylmethylene)benzenes 2a-c and 4 and a related acyclic analogue 6a were synthesised and converted to the corresponding Mannich bases 3a-c, 5 and 6b. Evaluation of these compounds against murine P388 and L1210 cells as well as human Molt 4/C8 and CEM T-lymphocytes revealed that the Mannich bases were more cytotoxic than the corresponding unsaturated ketones. 1,4-bis(3-Dimethylaminomethyl-2-oxo-1-cyclohexylmethylene)benzene dihydrochloride (3a) had lower IC(50) values than melphalan against the four cell lines and was 15 times more potent than this drug when examined against a panel of human tumours.

Sensitization of ara-C-resistant lymphoma cells by a pronucleotide analogue

Adequate intracellular concentrations of ara‐CMP, the monophosphorylated derivative of ara‐C, are essential for its cytotoxicity. The critical step for ara‐CMP formation is intracellular phosphorylation of ara‐C by deoxycytidine kinase (dCK). A common nucleoside resistance mechanism is mutation affecting the expression or the specificity of dCK. We describe the ability of a tert‐butyl S‐acyl‐thioethyl (SATE) derivative of ara‐CMP (UA911) to circumvent ara‐C resistance in a dCK‐deficient human follicular lymphoma cell line (RL‐G). The RL‐G cell line was produced by continuous exposure to gemcitabine and displayed low dCK mRNA and protein expression that conferred resistance both to ara‐C (2,250‐fold) and to gemcitabine (2,092‐fold). RL‐G cells were able to take up the UA911 pronucleotide by diffusion and metabolize it to the corresponding ara‐CMP and ara‐CTP nucleotides, exhibiting a 199‐fold reduction in resistance ratios, and a similar cell cycle arrest to the parental RL‐7 cells. Exposures to 10, 50 or 100 μM concentrations of UA911 produced 160 ± 7, 269 ± 8 and 318 ± 62 pmol ara‐CTP/mg protein in RL‐7 cells, and 100 ± 12, 168 ± 10 and 217 ± 39 pmol ara‐CTP/mg protein in RL‐G cells, respectively. Exposure of RL‐G cells to underivatized, radiolabeled ara‐C produced no detectable amounts of the active triphosphate metabolites. We conclude that the UA911 pronucleotide is capable of overcoming dCK‐mediated resistance. This result can be attributed to the unique cellular metabolism of the SATE pronucleotides giving rise to the intracellular delivery of ara‐CMP to dCK‐deficient cells.

Anticonvulsants containing the N-(3-aryl-2-propenoyl) amido pharmacophore.

A series of 1-(3-aryl-2-propenoyl)-4-oxopiperidines (1) as well as some related semicarbazones (2) and thiosemi-carbazones (3) were prepared in order to determine whether the relative locations of aryl rings and amidic groups would lead to novel anticonvulsant agents. Initially the compounds were administered intraperito-neally to mice and examined in the maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) and neurotoxicity (NT) screens. The biodata revealed that anticonvulsant properties were displayed by most of the compounds in series (1), in half of the semicarbazones (2) while protection was absent by members of series (3). Molecular modeling was utilized in order to compare the positions of a phenyl ring in relation to amidic groups in representative compounds in series (1–3) with previously reported anticonvulsant agents. Molecular simplification of 4-oxo-1-(3-phenyl-2-propenoyl)piperidine (1a) led to 1-(3-phenyl-2-propenoyl)piperidine (7) and N,N-diethyl-cinnamamide (8) with retention of anticonvulsant properties. Both (1a) and (8) afforded protection in the hippocampal kindling screen in rats. When administered orally to rats, (1a) and (8) demonstrated activity in the MES screen and in the case of (8), a huge protection index was observed revealing it to be an important lead compound. The IC50 values of all of the compounds towards murine P388 cells were in excess of 50μM while several compounds displayed cytotoxicity towards Mycobacterium tuberculosis.

Cytotoxic mannich bases of 1-arylidene-2-tetralones

Various 1-arylidene-2-tetralones 1 had been shown previously to possess moderate cytotoxic properties unaccompanied by murine toxicity. The objective of the present investigation was to undertake different molecular modifications of representative members of series 1 with a view to discerning those structural features leading to increased potencies. All compounds were evaluated using human Molt 4/C8 and CEM T-lymphocytes as well as murine P388 and L1210 leukemic cells. The Mannich bases 2, 4, 5 and 7 possessed increased potencies compared to the corresponding unsaturated ketones 1 and in general were potent cytotoxics having IC50 values in the 0.2–10 μM range. QSAR using the cytotoxicity data for 2a–e suggested that potency was positively correlated with the size of the substituents in the arylidene aryl ring. Compounds 2a–f were evaluated using a panel of approximately 53 human tumour cell lines and, when all cell lines were considered, were more potent than the reference drug melphalan. In particular, marked antileukemic activity was displayed. Molecular modeling was utilized in order to evaluate whether the shapes of the different compounds contributed to the varying potencies observed. Representative compounds demonstrated minimal or no inhibiting properties towards human N-myristoyltransferase (NMT) and did not bind to calf thymus DNA. This study has revealed a number of unique lead molecules as candidate antineoplastic agents serving as prototypes for future development.