rifampin and Colonic-Neoplasms

WHO suggests that colon cancer incidences are rising steadily, propelling researchers to search for novel chemotherapeutic options. Metal-based chemotherapy is a potential forte to explore ruthenium-based complexes, exhibiting the capability to influence a variety of cellular targets. We discovered the chemotherapeutic effects of ruthenium-rifampicin complex on HT-29 and HCT-116 human colorectal cell lines and on a chemically developed murine colorectal cancer model. Complex was synthesized and characterized by analytical techniques and evaluation of antioxidant potential along with DNA binding capabilities. The complex minimizes cellular propagation and initiates apoptotic events in the colon cancer cell lines of HT-29 and HCT-116. The results of the in vivo study suggest that the complex has been successful in minimizing the wide spectrum of aberrant crypt foci and hyperplastic lesions, as well as encouraging elevated amounts of CAT, SOD and glutathione. Along with that, p53 could be modulated by the ruthenium-rifampicin complex to interfere with apoptosis in colon carcinoma, initiated by the intrinsic apoptotic trail facilitated through Bcl2 and Bax, thus controlling the Akt/mTOR/VEGF pathway coupled through the WNT/β-catenin trail. Ruthenium-rifampicin chemotherapy could interrupt, retract or interrupt the progression of colorectal cancer through modifying intrinsic apoptosis including the antiangiogenic pathway, thereby achieving the function of a potential contender in chemotherapy in the near future.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Cell Cycle; Colon; Colonic Neoplasms; Drug Combinations; Female; HCT116 Cells; HT29 Cells; Humans; Male; Mice, Inbred BALB C; Proto-Oncogene Proteins c-akt; Rats, Wistar; Rifampin; Ruthenium Compounds; Signal Transduction; TOR Serine-Threonine Kinases; Tumor Microenvironment; Tumor Suppressor Protein p53; Vascular Endothelial Growth Factor A

To further the development of a model for simultaneously assessing intestinal absorption and first-pass metabolism in vitro, Caco-2, LS180, T84, and fetal human small intestinal epithelial cells (fSIECs) were cultured on permeable inserts, and the integrity of cell monolayers, CYP3A4 activity, and the inducibility of enzymes and transporters involved in intestinal drug disposition were measured. Caco-2, T84, and fSIECs all formed tight junctions, as assessed by immunofluorescence microscopy for zonula occludens-1, which was well organized into circumscribing strands in T84, Caco-2, and fSIECs but was diffuse in LS180 cells. The transepithelial electrical resistance value for LS180 monolayers was lower than that for Caco-2, T84, and fSIECs. In addition, the apical-to-basolateral permeability of the paracellular marker Lucifer yellow across LS180 monolayers was greater than in fSIECs, T84, and Caco-2 monolayers. The transcellular marker propranolol exhibited similar permeability across all cells. With regard to metabolic capacity, T84 and LS180 cells showed comparable basal midazolam hydroxylation activity and was inducible by rifampin and 1α,25(OH)2D3 in LS180 cells, but only marginally so in T84 cells. The basal CYP3A4 activity of fSIECs and Caco-2 cells was much lower and not inducible. Interestingly, some of the drug transporters expressed in LS180 and Caco-2 cells were induced by either 1α,25(OH)2D3 or rifampin or both, but effects were limited in the other two cell lines. These results suggest that none of the cell lines tested fully replicated the drug disposition properties of the small intestine and that the search for an ideal screening tool must continue.

Topics: Biological Transport; Caco-2 Cells; Calcitriol; Carcinoma; Cell Line, Tumor; Cell Membrane Permeability; Colonic Neoplasms; Cytochrome P-450 CYP3A; Epithelial Cells; Humans; Intestinal Absorption; Intestine, Small; Pharmaceutical Preparations; Rifampin

Naturally occurring condensed quinolines have anticancer properties. In efforts to find active analogues, we designed and synthesized eight polycyclic heterocycles with a pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline framework (IND series). The compounds were evaluated for activity against colon (HCT-116 and S1-MI-80), prostate (PC3 and DU-145), breast (MCF-7 and MDAMB-231), ovarian (ov2008 and A2780), and hepatocellular (HepG2) cancer cells and against non-cancerous Madin Darby canine kidney (MDCK), mouse embryonic fibroblast (NIH/3T3), and human embryonic kidney cells (HEK293). IND-2, a 4-chloro-2-methyl pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline, exhibited more than ten-fold selectivity and potent cytotoxic activity against colon cancer cells relative to the other cancer and non-cancer cells. With five additional colon cancer cell lines (HT-29, HCT-15, LS-180, LS-174, and LoVo), IND-2 had similar cytotoxicity and selectivity, and sub-micromolar concentrations caused changes in the morphology of HCT-116 and HCT-15 cells. IND-2 did not activate the transactivating function of the pregnane X receptor (PXR), indicating that it does not induce PXR-regulated ABCB1 or ABCG2 transporters. Indeed, IND-2 was not a substrate of ABCB1 or ABCG2, and it induced cytotoxicity in HEK293 cells overexpressing ABCB1 or ABCG2 to the same extent as in normal HEK293 cells. IND-2 was cytotoxic to resistant colon carcinoma S1-MI-80 cells, approximately three- and five-fold more than SN-38 and topotecan, respectively. In HCT-116 colon cancer cells, IND-2 produced concentration-dependent changes in mitochondrial membrane potential, leading to apoptosis, and sub-micromolar concentrations caused chromosomal DNA fragmentation. These findings suggest that, by increasing apoptosis, IND-2 has potential therapeutic efficacy for colorectal cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Colonic Neoplasms; Dogs; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; HCT116 Cells; HEK293 Cells; Hep G2 Cells; Humans; Madin Darby Canine Kidney Cells; MCF-7 Cells; Mice; Pyrimidines; Quinolines

Pregnane X receptor (PXR) has been reported to regulate the expression of drug-metabolizing enzymes, such as the cytochrome P450 3A (CYP3A) family and transporters, such as multiple drug resistance 1 (MDR1). Fucoxanthin, the major carotenoid in brown sea algae, is a putative chemopreventive agent. In this study, we determined whether fucoxanthin could overcome drug resistance through attenuation of rifampin-induced CYP3A4 and MDR1 gene expression by PXR-mediated pathways in HepG2 hepatoma cells. We found that fucoxanthin (1-10 μM) significantly attenuated rifampin (20 μM)-induced CYP3A4, MDR1 mRNA and CYP3A4 protein expression at 24 h of incubation. Mechanistically, fucoxanthin strongly attenuated the PXR-mediated CYP3A4 promoter activity in HepG2 cells. In addition, fucoxanthin attenuated constitutive androstane receptor (CAR)- and rPXR-mediated CYP3A4 promoter activity in this cell line. Using the mammalian two-hybrid assay, we found that fucoxanthin significantly decreased the interaction between PXR and SRC-1, a PXR co-activator. Thus, fucoxanthin can decrease rifampin-induced CYP3A4 and MDR1 expression through attenuation of PXR-mediated CYP3A4 promoter activation and interaction between PXR and co-activator. These findings could lead to potentially important new therapeutic and dietary approaches to reduce the frequency of adverse drug reactions.

Topics: Adenocarcinoma; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Line, Tumor; Colonic Neoplasms; Constitutive Androstane Receptor; Cytochrome P-450 CYP3A; Hep G2 Cells; Humans; Pregnane X Receptor; Promoter Regions, Genetic; Receptors, Cytoplasmic and Nuclear; Receptors, Steroid; Rifampin; RNA, Messenger; Transcriptional Activation; Xanthophylls

Oxidative catabolism of 1α,25-dihydroxyvitamin D(3) [1α,25(OH)(2)D(3)] is mediated by either CYP24A1 or CYP3A4. In this paper, we tested whether induction of CYP3A4 in the LS180 intestinal cell model enhances clearance of 1α,25(OH)(2)D(3) and blunts its hormonal effect on expression of the apical membrane calcium transport protein, TRPV6. Treatment with the hPXR agonist rifampin significantly increased CYP3A4 mRNA content and catalytic activity, but had no effect on CYP24A1 or TRPV6 mRNA content. Pre-treating cells with rifampin for 48h, prior to a 24h 1α,25(OH)(2)D(3) treatment phase, was associated with a subsequent 48% increase in the elimination of 1α,25(OH)(2)D(3) and a 35% reduction of peak TRPV6 mRNA. Introduction of the CYP3A4 inhibitor, 6',7'-dihydroxybergamottin, an active inhibitor in grapefruit juice, reversed the effects of rifampin on 1α,25(OH)(2)D(3) clearance and TRPV6 expression. Over-expression of hPXR in LS180 cells greatly enhanced the CYP3A4 responsiveness to rifampin pretreatment, and elicited a greater relative suppression of TRPV6 expression and an increase in 1α,25(OH)(2)D(3) disappearance rate, compared to vector expressed cells, following hormone administration. Together, these results suggest that induction of CYP3A4 in the intestinal epithelium by hPXR agonists can result in a greater metabolic clearance of 1α,25(OH)(2)D(3) and reduced effects of the hormone on the intestinal calcium absorption, which may contribute to an increased risk of drug-induced osteomalacia/osteoporosis in patients receiving chronic therapy with potent hPXR agonists. Moreover, ingestion of grapefruit juice in the at-risk patients could potentially prevent this adverse drug effect.

Topics: Adenocarcinoma; Caco-2 Cells; Calcium; Cell Line, Tumor; Colonic Neoplasms; Cytochrome P-450 CYP3A; Dose-Response Relationship, Drug; Enzyme Induction; Humans; Pregnane X Receptor; Receptors, Steroid; Rifampin; Vitamin D

The development of multidrug resistance (MDR) is one of the major limitations in the treatment of cancer. Induction of P-glycoprotein (Pgp) has been regarded as one of the main mechanisms underlying anticancer drug-induced MDR. Since the induction of Pgp is (in part) regulated by the pregnane X receptor (PXR), the ability of several widely used anticancer drugs to activate PXR-mediated Pgp induction was investigated.. A Pgp-reporter gene assay was employed to determine the ability of a panel of widely used anticancer drugs to induce Pgp. To further assess whether PXR could be involved in the induction of Pgp by anticancer drugs, Pgp protein expression after treatment with the anticancer drugs was determined in both wild-type and PXR-knocked down LS180 cells. Furthermore, the effect of the anticancer drugs on the intracellular accumulation of the Pgp-probes rhodamine 123 and doxorubicin was determined.. Our study showed that vincristine, tamoxifen, vinblastine, docetaxel, cyclophosphamide, flutamide, ifosfamide and paclitaxel activate PXR-mediated Pgp induction, and were additionally shown to affect the intracellular accumulation of the Pgp probe rhodamine 123. Moreover, PXR activation was also shown to reduce the cytotoxic activity of the Pgp substrate doxorubicin in colon cancer cells.. Our results indicate that several anticancer drugs can activate PXR-mediated induction of Pgp and affect the accumulation of Pgp substrates.

Topics: Adenocarcinoma; Antibiotics, Antineoplastic; Antineoplastic Agents; Antitubercular Agents; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Blotting, Western; Cell Line, Tumor; Cell Survival; Chromatography, High Pressure Liquid; Colonic Neoplasms; Doxorubicin; Fluorescent Dyes; Humans; Plasmids; Pregnane X Receptor; Receptors, Steroid; Rhodamine 123; Rifampin; RNA Interference

The orphan nuclear receptor pregnane X receptor (PXR) plays an important role in the detoxification of foreign and endogenous chemicals, including bile acids. PXR promotes bile acid elimination by activating bile acid-detoxifying enzymes and transporters. Certain bile acids are known to promote colonic carcinogenesis by inducing colon cancer cell apoptosis. However, whether and how PXR plays a role in colon cancer apoptosis has not been reported. In this study, we showed that activation of PXR by genetic (using a constitutively activated PXR) or pharmacological (using PXR agonist rifampicin) means protected the PXR-overexpressing colon cancer HCT116 cells from deoxycholic acid-induced apoptosis. Interestingly, activation of PXR also protected HCT116 cells from adriamycin-induced cell death, suggesting that the antiapoptotic effect of PXR was not bile acid specific. Moreover, the antiapoptotic effect of PXR in HCT116 cells appeared to be independent of xenobiotic enzyme regulation, because these cells had little basal and inducible expression of bile acid-detoxifying enzymes. Instead, SuperArray analysis showed that PXR-mediated deoxycholic acid resistance was associated with up-regulation of multiple antiapoptotic genes, including BAG3, BIRC2, and MCL-1, and down-regulation of proapoptotic genes, such as BAK1 and TP53/p53. Treatment with rifampicin in colon cancer LS180 cells, a cell line known to express endogenous PXR, also inhibited apoptosis. Activation of PXR in transgenic mice inhibited bile acid-induced colonic epithelial apoptosis and sensitized mice to dimethylhydrazine-induced colonic carcinogenesis, suggesting that the antiapoptotic effect of PXR is conserved in normal colon epithelium. In summary, our results have established the antiapoptotic role of PXR in both human colon cancer cells and normal mouse colon epithelium.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Apoptosis Regulatory Proteins; bcl-2 Homologous Antagonist-Killer Protein; Blotting, Western; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Doxorubicin; Epithelial Cells; Flow Cytometry; HCT116 Cells; Humans; In Situ Nick-End Labeling; Inhibitor of Apoptosis Proteins; Mice; Mice, Transgenic; Myeloid Cell Leukemia Sequence 1 Protein; Pregnane X Receptor; Proto-Oncogene Proteins c-bcl-2; Receptors, Steroid; Reverse Transcriptase Polymerase Chain Reaction; Rifampin; Ubiquitin-Protein Ligases

The small intestinal wall serves as an important barrier for the entry of foreign substances into the organism. Of particular importance are enzymes and transporters that can inactivate or prevent the uptake of many xenobiotics including drugs. Some of the genes encoding these proteins are transcriptionally activated by xenobiotics, a response well studied in liver but less so in the intestine. The effect of the inducer drug rifampicin on intestinal cells was therefore evaluated both in vivo and in vitro.. Seven healthy volunteers were treated with rifampicin for 9 days and the global gene expression profile was analysed in RNA from duodenal biopsies taken before and after drug treatment. The gene expression profile was also assessed in LS174T cells derived from a human colon adenocarcinoma after exposure to 10 micromol/l rifampicin for 24 h.. We identified 32 genes that were upregulated and two genes that were downregulated by rifampicin treatment in vivo. The list of rifampicin regulated transcripts expectedly included drug metabolizing enzymes and drug transporters, but also genes involved in lipid and amino acid metabolism as well as genes not previously recognized to be part of the adaptation of intestinal cells to xenobiotic exposure. Only a limited number of these rifampicin-regulated transcripts were however also regulated by rifampicin in LS174T cells.. The similarities and differences of changes in gene expression after rifampicin treatment between duodenal biopsies and cell culture provide a new assessment of the extent and diversity of systems affected by drug exposure.

Topics: Adenocarcinoma; Antibiotics, Antitubercular; Biomarkers; Colonic Neoplasms; Duodenum; Gene Expression Profiling; Gene Expression Regulation; Humans; Oligonucleotide Array Sequence Analysis; Rifampin; RNA, Messenger; Transcription, Genetic; Tumor Cells, Cultured

Continuous use of St. John's wort decreases the bioavailabilities of a variety of drugs. This interaction is attributed to the induction of cytochrome P450 3A4 and/or P-glycoprotein. In this study, we aimed to examine the chronic effects of St. John's wort and its constituents, hyperforin and hypericin, on the expression and function of P-glycoprotein in an intestinal cell line, LS 180. We also examined the acute inhibitory effect of St. John's wort on P-glycoprotein by using LLC-GA5-COL150 cells, which overexpress P-glycoprotein. St. John's wort and hyperforin but not hypericin increased the expression of P-glycoprotein in LS 180 cells. Removal of St. John's wort resulted in a restoration of P-glycoprotein level within 48 h. The content of hyperforin in St. John's wort extract was high enough to induce P-glycoprotein, suggesting that the induction of P-glycoprotein by St. John's wort can be almost attributable to hyperforin. The LS 180 cells chronically exposed to St. John's wort or hyperforin exhibited the increase in the function of P-glycoprotein assessed by the efflux of digoxin, and the activities correlated well with P-glycoprotein level. On the other hand, St. John's wort and its two constituents did not show any acute effect on P-glycoprotein-mediated transport of digoxin. St. John's wort induced P-glycoprotein in vitro that functions as a drug efflux pump. Hyperforin is considered to be a primary cause of the inductive effect of St. John's wort. Long-term administration of St. John's wort may cause clinically significant decrease in the plasma concentrations of P-glycoprotein substrates.

Topics: Adenocarcinoma; Animals; Anthracenes; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Bridged Bicyclo Compounds; Cell Line, Tumor; Colonic Neoplasms; Digoxin; Humans; Hypericum; LLC-PK1 Cells; Perylene; Phloroglucinol; Plant Extracts; Rifampin; Swine; Terpenes; Transfection

The bioassay- and spectroscopic-guided fractionation of the antimalarial extract from a Jamaican sponge, Plakortis sp., resulted in the isolation of three metabolites. The previously reported bromoaromatic filiformin (1) was obtained from our sample of Plakortis sp., and the potential origins of this compound are discussed. The peroxide-containing metabolite, plakortide F (2), is a more typical Plakortis metabolite and was shown to exhibit significant activity against Plasmodium falciparum in vitro. The isolation, structure, and bioactivity of a new lactone, plakortone G (3), are also reported.

Topics: Animals; Antimalarials; Bromobenzenes; Chromatography, High Pressure Liquid; Colonic Neoplasms; Dioxanes; Gas Chromatography-Mass Spectrometry; Hepatitis B; HIV; Humans; Jamaica; Lactones; Leukemia P388; Lung Neoplasms; Mice; Molecular Structure; Mycobacterium tuberculosis; Neoplasms, Unknown Primary; Nuclear Magnetic Resonance, Biomolecular; Plasmodium berghei; Plasmodium falciparum; Porifera; Spectrometry, Mass, Electrospray Ionization; Tumor Cells, Cultured

Xenobiotics frequently induce proteins involved in their detoxification. Because many drugs that are metabolized by human cytochromes P450 (CYP) 3A4 and 3A5 are also transported by the drug efflux pump P-glycoprotein, we determined whether expression of these proteins was altered by a variety of drugs in a cell line derived from a human colon adenocarcinoma, LS180/WT, and its adriamycin-resistant subline, LS180/AD50. P-glycoprotein and CYP3A4 were constitutively expressed in both LS180/AD50 and LS180/WT cells, and both proteins were up-regulated after treatment with many drugs, including rifampicin, phenobarbital, clotrimazole, reserpine, and isosafrole. However, there were some exceptions because P-glycoprotein was up-regulated by midazolam and nifedipine, whereas CYP3A4 was not. CYP3A5, which is also constitutively expressed in these cells, remained unchanged with most drug treatments but was up-regulated by reserpine and clotrimazole. The apparent coordinated coexpression of the CYP3A gene family and P-glycoprotein in the LS180 cells suggests that for common orally administered drugs, P-glycoprotein may play an important role in net drug absorption and drug/drug interactions of shared CYP3A4/P-glycoprotein substrates.

Topics: Adenocarcinoma; ATP Binding Cassette Transporter, Subfamily B, Member 1; Base Sequence; Blotting, Northern; Cell Line; Clotrimazole; Colonic Neoplasms; Cytochrome P-450 CYP2E1; Cytochrome P-450 Enzyme System; Dexamethasone; DNA Primers; Doxorubicin; Gene Expression Regulation, Neoplastic; Humans; Midazolam; Mixed Function Oxygenases; Molecular Sequence Data; Multigene Family; Phenobarbital; Phenytoin; Polymerase Chain Reaction; Rifampin; Tumor Cells, Cultured; Verapamil

The P-glycoprotein (Pgp) efflux pump can influence the hepatocellular concentration of xenobiotics that are modulators and substrates of cytochrome P4503A (CYP3A). We tested the hypothesis that Pgp is a determinant of drug-inducible expression of CYP3A. The magnitude of CYP3A induction by rifampicin was compared in the human parental colon carcinoma cell line LS 180/WT (wild type) and in two derivative clones overexpressing the human multidrug resistance gene MDR1 (also designated PGY1) because of either drug selection (LS 180/ADR) or transfection with MDRI cDNA (LS 180/MDR). In both MDR1 cDNA-overexpressing clones, rifampicin induction of CYP3A mRNA and protein was decreased and required greater rifampicin concentrations compared with parental cells. The role of Pgp in regulation of CYP3A expression in vivo was analyzed in mice carrying a targeted disruption of the mdr1a mouse gene. Oral treatment with increasing doses of rifampicin resulted in elevated drug levels in the livers of mdr1a (-/-) mice compared with mdr1a (+/+) mice at all doses. Consistent with the enhanced accumulation of rifampicin in mdr1a (-/-) mice, lower doses of rifampicin were required for induction of CYP3A proteins, and the magnitude of CYP3A induction was greater at all doses of rifampicin in mdr1a (-/-) mice compared with mdr1a (+/+) mice. We conclude that Pgp-mediated transport is a critical element influencing the CYP3A inductive response.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Blotting, Northern; Cell Line; Colonic Neoplasms; Cytochrome P-450 CYP2E1; Cytochrome P-450 Enzyme System; Drug Resistance, Multiple; Gene Expression Regulation, Enzymologic; Genotype; Humans; Kinetics; Mice; Mice, Inbred Strains; Mice, Knockout; Microsomes, Liver; Mixed Function Oxygenases; Rifampin; Tumor Cells, Cultured; Vinblastine