ABSTRACT
Inflammatory breast cancer (IBC) is a highly metastatic, lethal form of breast cancer that lacks targeted therapeutic strategies. Inspired by the promising cytotoxicity of gambogic acid and related caged xanthones in spheroidsMARY-X, an in vitro preclinical IBC model, we constructed a library of synthetic analogs and performed structure-activity relationship studies. The studies revealed that functionalizing the A-ring of the caged xanthone framework can significantly affect potency. Specifically, introduction of hydroxyl or fluorine groups at discrete positions of the A-ring leads to enhanced cytotoxicity at submicromolar concentrations. These compounds induce complete dissolution of spheroidsMARY-X with subsequent apoptosis of both the peripherally- and centrally-located cells, proliferative and quiescent-prone (e.g. hypoxic), respectively. These results highlight the structural flexibility and pharmacological potential of the caged xanthone motif for the design of IBC-targeting therapeutics.
Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms/drug therapy , Inflammatory Breast Neoplasms/drug therapy , Xanthones/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Apoptosis/drug effects , Breast Neoplasms/pathology , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Female , Humans , Inflammatory Breast Neoplasms/pathology , Molecular Structure , Structure-Activity Relationship , Xanthones/chemical synthesis , Xanthones/chemistryABSTRACT
The limited translational value in clinic of analyses performed on 2-D cell cultures has prompted a shift toward the generation of 3-dimensional (3-D) multicellular systems. Here we present a spontaneously-forming in vitro cancer spheroid model, referred to as spheroids(MARY-X), that precisely reflects the pathophysiological features commonly found in tumor tissues and the lymphovascular embolus. In addition, we have developed a rapid, inexpensive means to evaluate response following drug treatment where spheroid dissolution indices from brightfield image analyses are used to construct dose-response curves resulting in relevant IC50 values. Using the spheroids(MARY-X) model, we demonstrate the unique ability of a new class of molecules, containing the caged Garcinia xanthone (CGX) motif, to induce spheroidal dissolution and apoptosis at IC50 values of 0.42 +/-0.02 µM for gambogic acid and 0.66 +/-0.02 µM for MAD28. On the other hand, treatment of spheroids(MARY-X) with various currently approved chemotherapeutics of solid and blood-borne cancer types failed to induce any response as indicated by high dissolution indices and subsequent poor IC50 values, such as 7.8 +/-3.1 µM for paclitaxel. Our studies highlight the significance of the spheroids(MARY-X) model in drug screening and underscore the potential of the CGX motif as a promising anticancer pharmacophore.
Subject(s)
Antineoplastic Agents/chemistry , Drug Evaluation, Preclinical/methods , Drug Screening Assays, Antitumor/methods , Neoplasms/drug therapy , Spheroids, Cellular/metabolism , Amino Acid Motifs , Animals , Apoptosis , Cell Line, Tumor , Garcinia/chemistry , Humans , Immunohistochemistry , Inhibitory Concentration 50 , Magnetic Resonance Spectroscopy , Microscopy, Confocal , Microscopy, Fluorescence , Neoplasm Transplantation , Tumor Cells, Cultured/drug effects , Xanthones/chemistryABSTRACT
Identification of novel drug targets and chemotherapeutic agents is a high priority in the fight against cancer. Here, we report that MAD-28, a designed cluvenone (CLV) derivative, binds to and destabilizes two members of a unique class of mitochondrial and endoplasmic reticulum (ER) 2Fe-2S proteins, mitoNEET (mNT) and nutrient-deprivation autophagy factor-1 (NAF-1), recently implicated in cancer cell proliferation. Docking analysis of MAD-28 to mNT/NAF-1 revealed that in contrast to CLV, which formed a hydrogen bond network that stabilized the 2Fe-2S clusters of these proteins, MAD-28 broke the coordinative bond between the His ligand and the cluster's Fe of mNT/NAF-1. Analysis of MAD-28 performed with control (Michigan Cancer Foundation; MCF-10A) and malignant (M.D. Anderson-metastatic breast; MDA-MB-231 or MCF-7) human epithelial breast cells revealed that MAD-28 had a high specificity in the selective killing of cancer cells, without any apparent effects on normal breast cells. MAD-28 was found to target the mitochondria of cancer cells and displayed a surprising similarity in its effects to the effects of mNT/NAF-1 shRNA suppression in cancer cells, causing a decrease in respiration and mitochondrial membrane potential, as well as an increase in mitochondrial iron content and glycolysis. As expected, if the NEET proteins are targets of MAD-28, cancer cells with suppressed levels of NAF-1 or mNT were less susceptible to the drug. Taken together, our results suggest that NEET proteins are a novel class of drug targets in the chemotherapeutic treatment of breast cancer, and that MAD-28 can now be used as a template for rational drug design for NEET Fe-S cluster-destabilizing anticancer drugs.
Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms/drug therapy , Mitochondrial Proteins/chemistry , Ribonucleoproteins/chemistry , Breast Neoplasms/chemistry , Cell Line, Tumor , Cell Proliferation , Cell Survival , Cluster Analysis , Drug Design , Female , Humans , Iron-Sulfur Proteins/chemistry , MCF-7 Cells , Molecular Conformation , Molecular Docking Simulation , Molecular Targeted Therapy , Software , Xanthones/chemistryABSTRACT
Different series of N-alkylated diamines and their derivatives condensed to quinic acid were synthesized and tested for antibacterial properties against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Mycobacterium tuberculosis. The lipophilic chain and carbohydrate moiety modulate the antibacterial activity and the compounds showed a structure-activity relationship. Overall, 11 compounds displayed better activity than chloramphenicol against Gram-positive and Gram-negative bacteria. Monoalkylated amines 2a-h displayed an activity similar to that of ethambutol against Mycobacterium tuberculosis.
Subject(s)
Amides/chemical synthesis , Amides/pharmacology , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/pharmacology , Diamines/chemical synthesis , Diamines/pharmacology , Quinic Acid/analogs & derivatives , Alkylation , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Microbial Sensitivity Tests , Quinic Acid/chemical synthesis , Quinic Acid/chemistry , Quinic Acid/pharmacology , Structure-Activity Relationship , Surface-Active Agents/pharmacologyABSTRACT
Leishmanicidal and trypanocidal activity of seventeen lipophilic diamines was evaluated in vitro against Leishmania braziliensis, L. chagasi, and Trypanosoma cruzi. Twelve compounds presented anti-Leishmania and six showed anti-T. cruzi amastigote activity. Compound 14 (N-tetradecyl-1,4-butanediamine) was the most active against both L. braziliensis (IC50 = 2.6 µm) and L. chagasi (IC50 = 3.0 µm) which showed a selectivity index (SI) >100. N-decyl-1,6-hexanediamine (compound 9) presented an IC50 = 1.6 µm and SI >187 and was over six times more potent than the reference drug benznidazole against T. cruzi. Treatment of infected or uninfected macrophages with compounds 9 and 14 did not induce significant TNFα and NO production. Four compounds (15, 16, 22, and 23) inhibited 78.9%, 77.7%, 83.7%, and 70.1% of rTRLb activity, respectively, and compound 23 inhibited 73.3% of rTRTc activity at 100 µm. A concentration-dependent effect on mitochondrial membrane depolarization was observed in T. cruzi epimastigotes treated with compound 9, suggesting this mechanism may be involved in the trypanocidal effect. On the contrary, in L. braziliensis promastigotes treated with compound 14, no mitochondrial depolarization was observed. Our results demonstrate that N-decyl-1,6-hexanediamine and N-tetradecyl-1,4-butanediamine are promising molecules for the development of novel leading compounds against T. cruzi and Leishmania spp., particularly given a possible alternative mechanism of action.