LS180 Cell Research Articles

Synthesis and antiproliferative activity evaluation of imidazole-based indeno[1,2-b]quinoline-9,11-dione derivatives

A series of new imidazole substituted indeno[1,2-b]quinoline-9,11-dione derivatives were synthesized and evaluated for their antiproliferative effects on HeLa, LS180, MCF-7 and Jurkat human cancer cell lines. Antiproliferative effects were evaluated using MTT assay. Prepared compounds exhibited weak to good antiproliferative activity in evaluated cell lines. Prepared compounds were more potent in Jurkat cell line when compared to LS180, HeLa and MCF-7 cell lines. Compounds 29 (IC16 = 0.7 μM) and 31 (IC16 = 1.7 μM) and 33 (IC16 = 1.7 μM) were found to be the most potent molecules on Jurkat cell lines. Moreover; it was found that some of the tested compounds bearing imidazole-2-yl moiety on the C11-position of dihydropyridine ring exhibited superior antiproliferative activity in comparison to cis-platin especially in Jurkat cell line (compounds 29, 31, and 33). It seemed that the introduction of electron-withdrawing groups on the imidazole ring enhanced the antiproliferative potential of these compounds (compounds 27, 29 and 31). The results of this study proposed that some of the imidazole substituted indeno[1,2-b]quinoline-9,11-dione compounds may act as efficient anticancer agents in vitro, emphasizing their potential role as a source for rational design of potent antiproliferative agents.

Phenylpropiophenone derivatives as potential anticancer agents: Synthesis, biological evaluation and quantitative structure–activity relationship study

Series of twelve chalcone and propafenone derivatives has been synthesized and evaluated for anticancer activities against HeLa, Fem-X, PC-3, MCF-7, LS174 and K562 cell lines. The 2D-QSAR and 3D-QSAR studies were performed for all compounds with cytotoxic activities against each cancer cell line. Partial least squares (PLS) regression has been applied for selection of the most relevant molecular descriptors and QSAR models building. Predictive potentials of the created 2D-QSAR and 3D-QSAR models for each cell line were compared, by use of leave-one-out cross-validation and external validation, and optimal QSAR models for each cancer cell line were selected. The QSAR studies have selected the most significant molecular descriptors and pharmacophores of the chalcone and propafenone derivatives and proposed structures of novel chalcone and propafenone derivatives with enhanced anticancer activity on the HeLa, Fem-X, PC-3, MCF-7, LS174 and K562 cells.

Characterization of anti-Tn-antigen MLS128 binding proteins involved in inhibiting the growth of human colorectal cancer cells

MLS128 monoclonal antibody, which binds an epitope consisting of two or three consecutive Tn-antigens, inhibits colon cancer cell growth by binding to a 110 kDa glycoprotein (GP). Previous studies suggested a possible association of insulin-like growth factor-I receptor (IGF-IR) signaling in the inhibition of colon cancer cell growth by MLS128 (Morita et al. Biosci Trends. 3, 32-37, 2009; Zamri et al. ibid. 6, 303-312, 2012). The current study thus investigated the nature of 110 kDa GP and its possible association with IGF-IR. MLS128 treatment for 3 days caused down-regulation of IGF-IR and disappearance of 110 kDa GP in HT29 colon cancer cells. Immunoprecipitation/immunoblotting experiments did not reveal a direct association between the two molecules in HT29 cells. In LS180 and HT29 cells, however, 110 kDa GP and IGF-IR were found in microdomains. Treatment of these cells with MLS128 for 3 days caused a reduction in the IGF-IR and 110 kDa GP associated with microdomains. Two-dimensional gel electrophoresis/MLS128 immunoblotting of HT29 and LS180 cell lysates and immunoprecipitates revealed three spots, from which tryptic peptides were recovered for protein sequencing. Identification of 110 kDa GP was unsuccessful due to its heterogeneity and resistance to tryptic digestion. During this study, however, limited proteolysis of 110 kDa GP was observed in the microdomain-associated 110 kDa GP from HT29 and LS180 cells, suggesting that protease-susceptible sites or domains exist in the middle of 110 kDa GP. This information on limited proteolysis may provide a clue to identifying 110 kDa GP.

Evernia prunastri and Pseudoevernia furfuraceae lichens and their major metabolites as antioxidant, antimicrobial and anticancer agents

The aim of this study is to investigate chemical composition of acetone extracts of the lichens Evernia prunastri and Pseudoevernia furfuraceae and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and some their major metabolites. HPLC–UV method was used for identification of secondary metabolites. Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. As a result of the study physodic acid had largest antioxidant activities. Total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also physodic acid. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method.

Biological Activities of Toninia candida and Usnea barbata Together with Their Norstictic Acid and Usnic Acid Constituents

The aim of this study was to investigate the chemical composition of acetone extracts of the lichens Toninia candida and Usnea barbata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts together with some of their major metabolites. The chemical composition of T. candida and U. barbata extracts was determined using HPLC-UV analysis. The major phenolic compounds in these extracts were norstictic acid (T. candida) and usnic acid (U. barbata). Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. Results of the study proved that norstictic acid had the largest antioxidant activity. The total content of phenols in the extracts was determined as the pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration using the broth microdilution method. The most active was usnic acid with minimum inhibitory concentration values ranging from 0.0008 to 0.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using the microculture tetrazolium test. Usnic acid was found to have the strongest anticancer activity towards both cell lines with IC50 values of 12.72 and 15.66 μg/mL.

QM study and conformational analysis of an isatin Schiff base as a potential cytotoxic agent

Isatin is an important compound from the biological aspect of view. It is an endogenous substance and moreover; various pharmacological activities have been reported for isatin and its derivatives. In-vitro cytotoxic effects of the prepared isatin Schiff bases toward HeLa, LS180 and Raji human cancer cell lines has been reported in our previous work. 3-(2-(4-nitrophenyl)hydrazono) indolin-2-one was found to be the most potent one among the studied compounds (IC(30) =12.2 and 21.8 μM in HeLa and LS-180 cell lines, respectively). Obtained biological data could be well interpreted using docking binding energies toward vascular endothelial growth factor receptor (VEGFR-2); a key anticancer target being biologically investigated against various isatin derivatives. In the present work, quantum mechanical (QM) method including functional B3LYP in association with split valence basis set using polarization functions (Def2-SVP) was used to estimate individual ligand-residue interaction energies for the docked 3-(2-(4-nitrophenyl)hydrazono) indolin-2-one into VEGFR-2 active site. Results were further interpreted via calculated polarization effects induced by individual amino acids of the receptor active site. A fairly good correlation could be found between polarization effects and estimated binding energies (R(2) =0.7227). Conformational analysis revealed that 3-(2-(4-nitrophenyl) hydrazono) indolin-2-one might not necessarily interact with the VEGFR-2 active site in its minimum energy conformation.

Chemical composition of three Parmelia lichens and antioxidant, antimicrobial and cytotoxic activities of some their major metabolites

The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia caperata, P. saxatilis and P. sulcata and antioxidant, antimicrobial and anticancer activities of some their major metabolites. The phytochemical analysis of acetone extracts of three Parmelia lichens were determined by HPLC-UV method. The predominant phenolic compounds in these extracts were protocetraric and usnic acids (P. caperata) and depsidone salazinic acid (other two species). Besides these compounds, atranorin and chloroatranorin, were also detected in some of these extracts. Antioxidant activity of their isolated metabolites was evaluated by free radical scavenging, superoxide anion radical scavenging and reducing power. As a result of the study salazinic acid had stronger antioxidant activity than protocetraric acid. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. Both compounds were highly active with minimum inhibitory concentration values ranging from 0.015 to 1mg/ml. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. Salazinic acid and protocetraric acid were found to be strong anticancer activity toward both cell lines with IC50 values ranging from 35.67 to 60.18μg/ml. The present study shows that tested lichen compounds demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggest that these lichens can be used as new sources of the natural antimicrobial agents, antioxidants and anticancer compounds.

Cofilin overexpression affects actin cytoskeleton organization and migration of human colon adenocarcinoma cells.

The dynamic reorganization of actin cytoskeleton is regulated by a large number of actin-binding proteins. Among them, the interaction of ADF/cofilin with monomeric and filamentous actin is very important, since it severs actin filaments. It also positively influences actin treadmilling. The activity of ADF/cofilin is reversibly regulated by phosphorylation and dephosphorylation at Ser-3, with the phosphorylated form (P-cofilin) being inactive. Here, we studied the effects of overexpression of cofilin and two cofilin variants in the human colon adenocarcinoma LS180 cell line. We have generated the LS180 cells expressing three different cofilin variants: WT (wild type), Ser 3 Ala (S3A) (constitutively active) or Ser 3 Asp (S3D) (constitutively inactive cofilin). The cells expressing WT cofilin were characterized by abundant cell spreading and colocalization of cofilin with the submembranous F-actin. Similar effects were observed in cells expressing S3A cofilin. In contrast, LS180 cells expressing S3D cofilin remained longitudinal in morphology and cofilin was equally distributed within the cell body. Furthermore, the migration ability of LS180 cells expressing different cofilin mutants was analyzed. In comparison to control cells, we have noticed a significant, approximately fourfold increase in the migration factor value of cells overexpressing WT type cofilin. The overexpression of S3D cofilin resulted in an almost complete inhibition of cell motility. The estimation of actin pool in the cytosol of LS180 cells expressing S3A cofilin has shown a significantly lower level of total actin in reference to control cells. The opposite effect was observed in LS180 cells overexpressing S3D cofilin. In summary, the results of our experiments indicate that phosphorylation “status” of cofilin is a factor affecting the actin cytoskeleton organization and migration abilities of colon adenocarcinoma LS180 cells.

Synthesis, cytotoxicity and calcium antagonist activity of novel imidazolyl derivatives of 1,8-acridinediones

A series of novel imidazolyl derivatives of fully and partially hydrogenated 1,8-acridinediones were synthesized and assessed for their cytotoxic activity on four different human cancer cell lines (HeLa, MCF-7, LS-180, and Raji cells). Although being inactive on LS-180 and Raji cell lines, the compounds showed weak to moderate anti-tumor activities on other cell lines and their IC50 ranged from 31.7 to more than 100 μM. Among the synthesized compounds 12b, 13b, 12c and 13c, bearing an electronattracting substituent on the imidazole ring, and 12f and 13f, with a benzyl substituent, showed higher activities. Furthermore, the calcium channel antagonist activity of the derivatives, an undesired effect when these compounds are used as anti-tumor agents, was much lower than that of Nifedipine, a reference antagonist. Imidazolyl derivatives of 1,8-acridinedione represent an interesting template, showing promising biological properties. Further investigation on this chemical scaffold could potentially lead to the discovery of cytotoxic agents with low calcium channel blocking activity.

VDR/RXR and TCF4/β-catenin cistromes in colonic cells of colorectal tumor origin: impact on c-FOS and c-MYC gene expression.

Many of the transcriptional and growth regulating activities of 1α,25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] in the intestine and colon are recapitulated in the human colorectal cancer cell LS180. We therefore used this line together with chromatin immunoprecipitation-seq and gene expression analyses to identify the vitamin D receptor (VDR)/retinoid X receptor (RXR) and transcription factor 7-like 2 (TCF7L2/TCF4)/β-catenin cistromes and the genes that they regulate. VDR and RXR colocalized to predominantly promoter distal, vitamin D response element-containing sites in a largely ligand-dependent manner. These regulatory sites control the expression of both known as well as novel 1,25-(OH)(2)D(3) target genes. TCF4 and β-catenin cistromes partially overlapped, contained TCF/lymphoid enhancer-binding factor consensus elements, and were only modestly influenced by 1,25-(OH)(2)D(3). However, the two heterodimer complexes colocalized at sites near a limited set of genes that included c-FOS and c-MYC; the expression of both genes was modulated by 1,25-(OH)(2)D(3). At the c-FOS gene, both VDR/RXR and TCF4/β-catenin bound to a single distal enhancer located 24 kb upstream of the transcriptional start site. At the c-MYC locus, however, binding was noted at a cluster of sites between -139 and -165 kb and at a site located -335 kb upstream. Examined as isolated enhancer fragments, these regions exhibited basal and 1,25-(OH)(2)D(3)-inducible activities that were interlinked to both VDR and β-catenin activation. These data reveal additional complexity in the regulation of target genes by 1,25-(OH)(2)D(3) and support a direct action of both VDR and the TCF4/β-catenin regulatory complex at c-FOS and c-MYC.

Synthesis, Cytotoxicity, and QSAR Study of New Aza‐cyclopenta[b]fluorene‐1,9‐dione Derivatives

Thirty novel derivatives of aza-cyclopenta[b]fluorene-1,9-dione were synthesized, and their cytotoxic activities were tested against HeLa, LS180, MCF-7, and Raji cancer cell lines by MTT assay. Two derivatives containing nitrofuryl moiety, including 10-(5-nitro-furan-2-yl)-2,3-dihydro-4-aza-cyclopenta[b]fluorene-1,9-dione (IC(50) range: 5.7-13.0 μm) and 10-(5-Nitro-furan-2-yl)-2,3,4,10-tetrahydro-4-aza-cyclopenta[b]fluorene-1,9-dione (IC(50) range: 3.6-20.2 μm), as well as 10-(2-Nitro-phenyl)-2,3,4,10-tetrahydro-4-aza-cyclopenta[b]fluorene-1,9-dione (IC(50) range: 3.1-27.1 μm) with nitrophenyl moiety on C10 position, were the most effective compounds. Furthermore, the effect of physiochemical descriptors on the cytotoxicity was evaluated by quantitative structure-activity relationship analysis. The quantitative structure-activity relationship results showed that molecular dipole moment, molar refractivity, fragment-based parameters, and some topological indices were influential on the cytotoxic effect. Finally, the good correlation that was found among cytotoxic data obtained from different cell lines may be an implication of a common cytotoxic mechanism in these cell lines. These findings provide useful structural information for the rational design and synthesis of efficient chemotherapeutic agents for treatment for cancer.

Antioxidant, Antimicrobial, and Anticancer Activity of 3 Umbilicaria Species

The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activity of the acetone extracts of the lichens Umbilicaria crustulosa, U. cylindrica, and U. polyphylla. Antioxidant activity was evaluated by 5 separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds, and determination of total flavonoid content. Of the lichens tested, U. polyphylla had largest free radical scavenging activity (72.79% inhibition at a concentration of 1 mg/mL), which was similar as standard antioxidants in the same concentration. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was extract of U. polyphylla with minimum inhibitory concentration values ranging from 1.56 to 12.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All extracts were found to be strong anticancer activity toward both cell lines with IC₅₀ values ranging from 28.45 to 97.82 μg/mL. The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggests that lichens may be used as possible natural antioxidant, antimicrobial, and anticancer agents.

Antioxidant, antimicrobial and anticancer activity of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis

BackgroundThe aim of this study is to investigate in vitro antioxidant, antimicrobial and anticancer activity of the acetone extracts of the lichens Cladonia furcata, Lecanora atra and Lecanora muralis.MethodsAntioxidant activity was evaluated by five separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds and determination of total flavonoid content. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method against six species of bacteria and ten species of fungi. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method.ResultsOf the lichens tested, Lecanora atra had largest free radical scavenging activity (94.7% inhibition), which was greater than the standard antioxidants. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. Extract of Cladonia furcata was the most active antimicrobial agent with minimum inhibitory concentration values ranging from 0.78 to 25 mg/mL. All extracts were found to be strong anticancer activity toward both cell lines with IC50 values ranging from 8.51 to 40.22 μg/mL.ConclusionsThe present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial and anticancer effects. That suggest that lichens may be used as as possible natural antioxidant, antimicrobial and anticancer agents to control various human, animal and plant diseases.

The set gene is a potential oncogene in human colorectal adenocarcinoma and oral squamous cell carcinoma

The purpose of this study was to determine whether set gene plays a role in the tumorigenesis of human colorectal adenocarcinoma and oral squamous cell carcinoma. We used the human colon carcinoma cell line Ls174 and oral squamous cell carcinoma cell line HSC3 to evaluate the effect of set suppression on cancer cell proliferation and apoptosis. Using real-time PCR, we examined set gene expression in human colorectal adenocarcinoma tissues and matched normal colorectal tissues. Thirty pairs of colorectal adenocarcinoma tissues and matched normal colorectal tissues were used for real-time PCR. We transfected human colon carcinoma cell line Ls174 and oral squamous cell carcinoma cell line HSC3 with siRNA against the set gene. The effect of set gene suppression on cancer cell proliferation and apoptosis were studied by MTT assay and flow cytometry. Real-time PCR indicated that set gene expression was up-regulated in 70% of tumor samples (21 out of 30 samples). siRNA2 sequences significantly decreased set mRNA levels in Ls174 and HSC3 cells. The inhibitory rate in the two cell lines was 55.91 and 71.57%, respectively. MTT assay revealed a 21.4% inhibition on cell proliferation in HS174 cells and a 20.2% inhibition in HSC3 cells. Flow cytometry data indicated that the cell apoptosis rate was 18.37% in Ls174 cells and 17.97% in HSC3 cells; these rates were significantly higher than those of the control groups. In conclusion, the set gene was found to play a role in the tumorigenesis of human colorectal adenocarcinoma. It may promote tumorigenesis by enhancing cancer cell proliferation and inhibiting cancer cell apoptosis.

Apoptotic effect of imatinib on human colon adenocarcinoma cells: Influence on actin cytoskeleton organization and cell migration

Imatinib mesylate (STI571) is the first member of a new class of agents that act by inhibiting specific tyrosine kinases, rather than killing all rapidly dividing cells. This drug is usually used in the treatment of chronic myelogenous leukemia and gastrointestinal stromal tumors. It was recognized to inhibit activity of kinases such as Bcr/Abl, platelet-derived growth factor receptor, and c-kit. These proteins play important roles in cell growth, motility, and survival. Therefore, studies on the biological effects of imatinib on different cellular models are very important. Human colon adenocarcinoma LS180 cell line was used in the studies presented. Cells were exposed to 0.1–100 μM imatinib for 24 and 48 h. Dose-dependent decreases in cell viability and morphological changes were observed. Moreover, the apoptotic effect of imatinib (10 μM, 50 μM) after 24 h of exposure was demonstrated as evaluated by translocation of phosphatidylserine to external membrane leaflet and by increased activity of caspase-3. Special attention was focused on imatinib influence on actin cytoskeleton organization and migration ability of LS180 cells. Distinct alterations in actin cytoskeleton architecture occurred in response to drug treatment, accompanied by appearance of filamentous actin aggregates and decrease in actin polymerization state. These changes were correlated with remarkable decrease in cell migration capacity. In summary, our data clearly demonstrate that imatinib induces apoptosis and inhibits human colon adenocarcinoma cell migration. Therefore, this drug may have potential in colon cancer therapy in the future.

Hypoxia and lineage specification of cell line-derived colorectal cancer stem cells

Hypoxia is an important regulator of normal and cancer stem cell (CSC) differentiation. Colorectal CSCs from SW1222, LS180, and CCK81 colorectal cancer-derived cell lines are able to differentiate into complex 3D lumen-containing structures in normoxia, whereas in hypoxia, they form undifferentiated dense colonies that have reduced expression of the enterocyte differentiation marker CDX1, lack goblet cell formation, and have increased expression of BMI1 and activated Notch1. Hypoxia increases the clonogenicity of CSCs, which is cumulative as each round of hypoxia enriches for more CSCs. The hypoxic phenotype is reversible, because cells from hypoxic-dense colonies are able to reform differentiated structures when regrown in normoxia. We show that CDX1 is able to stimulate the generation of lumens even in hypoxia and has a negative feedback on BMI1 expression. Knockdown of CDX1 reduces lumen formation but does not affect goblet cell formation, suggesting that enterocytes and goblet cells form from different progenitor cells. Notch inhibition by dibenzazepine (DBZ) allowed CSCs to form goblet cells in both normoxia and hypoxia. Finally, we show that Hif1α, but not CA9, is an important mediator of the effects of hypoxia on the clonogenicity and differentiation of CSCs. In summary, hypoxia maintains the stem-like phenotype of colorectal cell line-derived CSCs and prevents differentiation of enterocytes and goblet cells by regulating CDX1 and Notch1, suggesting that this regulation is an important component of how hypoxia controls the switch between stemness and differentiation in CSCs.

Synthesis and Cytotoxicity Study of New Cyclopenta [b] quinoline-1,8-dione Derivatives.

DNA intercalators belong to aromatic heterocyclic compounds interacting reversibly with DNA. These compounds have been used extremely as cytotoxic agents against cancer. In this study, the synthesis and biological activity of some novel derivatives of cyclopenta [b] quinoline-1, 8-dione as new intercalating agent were investigated. Twenty novel derivatives of cyclopenta [b] quinoline-1, 8-dione were synthesized by molecular condensation of equivalent amount of 3-imino cyclopentanone, corresponding aldehyde and cyclohexane-1, 3-dione. Then, their cytotoxic activity was evaluated against HeLa, LS180, MCF-7 and Raji cancer cell lines by MTT assay. The results of cytotoxic activity evaluation indicate that the most of synthesized compounds show weak cytotoxic effect on the different cell lines (IC50 of these compounds is higher than 50 or 100 µ ). According to previous studies, in the case of compounds with the weak biological activity, it is more suitable to use IC15 and IC30 instead of IC50 as the indicator of biological activity. Since most of compounds have weak cytotoxic effect, we also calculated IC15 and IC30 for evaluating the cytotoxic activity of synthesized compounds. The most potent compound, 6 h (9-(3-Bromo-phenyl)-4-pheny l-2, 3, 5, 6, 7, 9-hexahydro-4H-cyclopenta [b] quinoline-1, 8-dione), containing bromophenyl moiety and phenyl substitute on nitrogen of central quinoline ring, show significant cytotoxic activity especially in Raji and HeLa cell lines (IC30: 82 and 24.4 μ M respectively) comparing to other compounds. Although the results of cytotoxic activity evaluation demonstrated that the in-vitro anti-cancer effect of synthesized compounds are mainly low, it seems that this structure can be used as a novel cytotoxic scaffold for further modification and design of novel potent compounds.

Design, Synthesis and Evaluation of Cytotoxicity of Novel Chromeno[4,3‐b]quinoline Derivatives

In the present work 15 new 1,4-dihydropyridines (DHPs) bearing a coumarin ring were synthesized and assessed on 4 different human cancer cell lines (HeLa, K562, LS180, and MCF-7). Although, all the derivatives were inactive on LS180 cell line, the results on other cells showed that these compounds had weak to moderate antitumoral activities and their IC(50) ranged from 25 to >100 µM. Among the synthesized compounds, 7-(2-nitrophenyl)-8,9,10,12-tetrahydro-7H-chromeno[4,3-b]quinoline-6,8-dione (6a) demonstrated the highest activity (IC(50) range in different cell lines: 25.4-58.6 µM). Furthermore, the calcium channel antagonist activity of the derivatives, an undesired effect when these compounds are used as antitumoral agents, was much lower than nifedipine, a reference antagonist. In conclusion, this group of compounds seems to have promising biological properties and further investigation on this group could potentially lead to the discovery of cytotoxic agents with low calcium channel blocking activity.

Effects ofCurcumaExtracts and Curcuminoids on Expression of P-glycoprotein and Cytochrome P450 3A4 in the Intestinal Cell Culture Model LS180

Curcuma longa L. is a widely used spice. Its main ingredients, the curcuminoids, are used in the treatment of inflammatory diseases and cancer. Bioavailability of curcuminoids is low, and huge amounts remain in the intestine. We therefore aimed to investigate their interaction potential with the ABC-transporter P-glycoprotein (P-gp, product of the MDR1/ABCB1 gene) and cytochrome P450 3A4 (CYP3A4) in an intestinal cell line (LS180). Intestinal P-gp and CYP3A4 play a major role in drug absorption, and consequently changes in their expression level could lead to interactions. The intestinal LS180 cell line was incubated with different Curcuma extracts, the single curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin), as well as a curcuminoid mixture. Changes in mRNA expression of MDR1 and the cytochrome CYP3A4 were measured by real-time RT-PCR. MDR1 mRNA expression was significantly but not relevantly downregulated by the curcuminoids, whereas the extracts had no significant effect on it. CYP3A4 mRNA expression did not alter significantly after treatment. Curcuma extracts, the single curcuminoids, and a curcuminoid mixture had no relevant effect on MDR1 and CYP3A4 mRNA expression in our intestinal cell system. Further studies are required to evaluate their effects in vivo.

Abstract 3488: In vitro activity of the IGF-1R inhibitor CP-751,871, as a single agent and in combination with paclitaxel, in lung and colon cell lines

Abstract Background: Signaling through the insulin-like growth factor 1 receptor (IGF-1R) has been implicated in the resistance to a number of clinically relevant anti-cancer agents. Objective: To assess the direct anti-tumour effects of the IGF-1R monoclonal antibody CP-751,871, as a single agent and in combination with paclitaxel, in lung and colon cancer cell lines. Methods: Four lung (A549, HCC78, H1299 and H460) and four colon (LS180, Colo205, HT29 and DLD1) cancer cell lines were selected. The experiments were designed to test the effects of simultaneous or sequential exposure to with CP-751,871 and/or paclitaxel. In the sequential arm, cells were pretreated with progressive doses of paclitaxel (from 0 to1000 nM) for 24 hours, drug removed by washing the cells twice, followed by the addition of cell culture medium plus CP-751,871 (50 μg/mL). After 48 hours of continuous presence of CP-751,871, cell growth was evaluated by WST-1 cell survival assays. In simultaneous treatment, cells were treated with both Paclitaxel (0-1000 nM) and CP-751,871 (50 μg/mL) for 48 hours. Flow cytometric analysis was used to estimate the effects on cell cycle and apoptosis. IGF-IR mRNA expression was determined by quantitative real-time PCR. Relative gene expression values were calculated by the ΔΔCt method. Results: No correlation between basal IGF-IR mRNA expression and response to CP-751,871 was observed. Flow cytometric analysis demonstrated that CP-751,871 enhanced cell cycle arrest at the G1/G0 checkpoint with minimal effects on apoptosis. Combined exposure to both CP-751,871 and Paclitaxel showed improved response in cell growth inhibition on HCC78, H1299, Colo205 and HT29 cell lines, and was statistically superior to Paclitaxel alone (p< 0.001) and CP-751,871 alone (p< 0.001). The results were even better after a sequential exposure. On the contrary, in H460, LS180 and DLD-1 cell lines, concomitant, but no sequential treatment resulted in antagonistic interactions. Conclusions: CP-751,871 showed a modest anti-tumour activity (about 30% growth inhibition in lung cancer cells; 10% growth inhibition in DLD1 and HT29 cell lines; and bigger inhibition in Colo205 (IC50=27.6 μg/mL) and LS180 (IC50=2.33 μg/mL) cell lines), predominantly cytostatic, that is not related to the mRNA expression. The effects of CP-751,871 in combination with paclitaxel depend on the cell line model and on the sequence of administration. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3488.