salicylates and Carcinoma--Small-Cell

Histone deacetylase (HDAC) inhibitors, such as valproic acid (VPA), constitute a novel class of anticancer agents that cause an increase in acetylated histones and thus restore the expression of dormant tumor-suppressor and other genes related to cell differentiation, cell-cycle arrest or apoptosis of tumor cells. The Ras inhibitor farnesylthiosalicylic acid (FTS, salirasib) attenuates cancer cell proliferation in vitro and in vivo and, under certain circumstances, induces cell death. FTS by itself does not induce differentiation or complete growth arrest. The abovementioned activity of VPA as a differentiation agent suggested that it might be worth investigating its possible therapeutic potential in synergistic combination with FTS. Here, we examined whether the combined application of VPA and FTS could synergistically inhibit the proliferation of cancer cells that express oncogenic K-Ras (A549 nonsmall-cell lung carcinoma cells), DLD1 (colon carcinoma cells) or chronically active wild-type K-Ras and constitutively active B-Raf (ARO, thyroid carcinoma cells). The results showed that combined treatment with VPA and FTS synergistically reduces proliferation in all of these cancer cell lines by downregulating Ras and blocking the expression of Survivin and Aurora A. These alterations, which were most pronounced following the combined treatment, led to a mitotic crisis, as reflected by mislocalization of the chromosomal passenger complex. Our findings thus demonstrate that combination therapy with VPA and FTS might offer a promising therapeutic approach to the treatment of epithelial tumors.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Aurora Kinases; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Cell Division; Cell Line, Tumor; Colonic Neoplasms; Down-Regulation; Farnesol; Flow Cytometry; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Inhibitor of Apoptosis Proteins; Lung Neoplasms; Microtubule-Associated Proteins; Protein Serine-Threonine Kinases; Reverse Transcriptase Polymerase Chain Reaction; RNA, Neoplasm; Salicylates; Survivin; Valproic Acid

Recently, there have been extensive efforts to evaluate the chemopreventive role of substances present in natural products. The aim of this study was to examine the effects of the main groups of compounds (salicylalcohol derivates, flavonoids, proanthocyanidins), and salicin isolated from willow bark extract BNO 1455 on proliferation and apoptosis in human colon and cancer cells.. We used human colon cyclooxygenase-2 (COX-2)-positive HT 29 and (COX-2)-negative HCT 116 or lung COX-2 proficient A 549 and low COX-2 expressing SW2 cells. After treatment for 72 h with various concentrations of single substances and acetylsalicylic acid (ASA) as control, inhibition of cell growth and cytotoxicity were measured by colorimetric WST-1 assay and propidium iodide uptake by flow cytometry, respectively. Apoptotic cells were identified by annexin V adhesion using flow cytometry.. Studies on dose-dependent effects of BNO 1455 and its fractions showed anti-proliferative activity of all compounds with 50% maximal growth inhibitory concentrations (GI(50)) between 33.3 and 103.3 microg/ml for flavonoids and proanthocyanidins fractions and 50.0-243.0 microg/ml for salicylalcohol derivates and extract. Apoptosis induction was confirmed by annexin V adherence and analysis of cell morphology based on light scattering characteristics using flow cytometry in all cell lines at GI(50).. We showed that willow bark extract BNO 1455 an its fractions inhibit the cell growth and promote apoptosis in human colon and lung cancer cell lines irrespective of their COX-selectivity.

Topics: Apoptosis; Carcinoma, Small Cell; Cell Proliferation; Cell Survival; Colonic Neoplasms; Cyclooxygenase 1; Cyclooxygenase 2; Flavonoids; Flow Cytometry; HT29 Cells; Humans; Lung Neoplasms; Membrane Proteins; Plant Bark; Plant Extracts; Proanthocyanidins; Salicylates; Salix; Tumor Cells, Cultured

MRP is a member of the ABC trafficking proteins thought to mediate the transport of glutathione S-conjugates and amphiphilic natural products. However, unlike P-glycoprotein, the biochemical mechanism by which MRP mediates the resistance to cytotoxic drugs is not clear. In this report, we describe the interactions of a quinoline-based drug, N-{4-[1-hydroxy-2-(dibutylamino)ethyl] quinolin-8-yl}-4-azidosalicylamide (IAAQ), with MRP. Our results demonstrate the ability of IAAQ to photoaffinity label a 190 kDa protein in resistant Small Cell Lung Cancer cells (H69/AR) but not in the parental H69 cells. The photoaffinity labeling of the 190 kDa protein with IAAQ was both saturable and specific. The identity of the 190 kDa protein, as MRP, was confirmed by immunoprecipitation with the monoclonal antibody, QCRL-1. Furthermore, a molar excess of LTC4, MK 571 or vinblastine inhibited the photoaffinity labeling of MRP with IAAQ in intact cells and plasma membranes. Cell growth and drug transport studies showed H69/AR cells to be less sensitive to and to accumulate less IAAQ than the parental H69 cells. In addition, MK 571 and doxorubicin increased the sensitivity to and the accumulation of IAAQ in H69/AR cells. Together, the results of this study show for the first time the direct binding of unaltered cytotoxic drug to MRP. Moreover, given the structural similarities between IAAQ and MK 571, we suggest that MK 571 modulates MRP-mediated resistance by direct binding to MRP.

Topics: Affinity Labels; Antibodies, Monoclonal; ATP-Binding Cassette Transporters; Binding Sites; Carcinoma, Small Cell; Cell Division; Doxorubicin; Drug Resistance, Multiple; Humans; Kinetics; Lung Neoplasms; Multidrug Resistance-Associated Proteins; Propionates; Quinolines; Salicylates; Tumor Cells, Cultured; Vinblastine

Topics: Adenocarcinoma; Antigen-Antibody Complex; Carcinoembryonic Antigen; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Cell Membrane; Cross Reactions; Electrophoresis, Starch Gel; Epitopes; Fluorescent Antibody Technique; Glycoproteins; Humans; Immunodiffusion; Immunoelectrophoresis; Lung Neoplasms; Microsomes; Salicylates; Sodium Dodecyl Sulfate