thiourea and Colonic-Neoplasms

Small series of acylguanidine and acylthiourea derivatives were synthesized in gram-scale and assayed for their ability to modulate the Hh signalling pathway. In vitro studies showed a low micromolar inhibitory activity toward tumor cell lines, while the oral administration revealed an excellent ADME profile in vivo. Compound 5 emerged as the most active and safe inhibitor of colon cancer cells both in vitro and in a xenograft mouse model. Based on these data, 5 could be prioritized to further development with the perspective of clinical studies.

Topics: Animals; Antineoplastic Agents; Cell Line; Cell Proliferation; Cell Survival; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Guanidine; Hedgehog Proteins; Humans; Mice; Mice, Nude; Molecular Structure; Neoplasms, Experimental; NIH 3T3 Cells; Structure-Activity Relationship; Thiourea

Clostridium difficile (C. difficile) is considered to be the major cause of the antibiotic-associated diarrhea and pseudomembranous colitis in animals and humans. The prevalence of C. difficile infections (CDI) has been increasing since 2000. Two exotoxins of C. difficile, Toxin A (TcdA) and Toxin B (TcdB), are the main virulence factors of CDI, which can induce glucosylation of Rho GTPases in host cytosol, leading to cell morphological changes, cell apoptosis, and cell death. The mechanism of TcdB-induced cell death has been investigated for decades, but it is still not completely understood. It has been reported that TcdB induces endoplasmic reticulum stress via PERK-eIF2α signaling pathway in CT26 cell line (BALB/C mouse colon tumor cells). In this study, we found that salubrinal, a selective inhibitor of eIF2α dephosphorylation, efficiently protects CT26 cell line against TcdB-induced cell death and tried to explore the mechanism underlying in this protective effect. Our results demonstrated that salubrinal protects CT26 cells from TcdB-mediated cytotoxic and cytopathic effect, inhibits apoptosis and death of the toxin-exposed cells via caspase-9-dependent pathway, eIF2α signaling pathway, and autophagy. These findings will be helpful for the development of CDI therapies.

Topics: Animals; Apoptosis; Autophagy; Bacterial Proteins; Bacterial Toxins; Caspase 9; Cell Death; Cell Line, Tumor; Cell Survival; Cinnamates; Colonic Neoplasms; Dose-Response Relationship, Drug; Eukaryotic Initiation Factor-2; Immunoblotting; Mice, Inbred BALB C; Microscopy, Fluorescence; Molecular Structure; Neuropeptides; Phosphorylation; Protective Agents; rac1 GTP-Binding Protein; Thiourea

The novel thiourea-functionalized silicon nanoparticles (SiNPs) have been successfully synthesized using allylamine and sulforaphane, an important anticancer drug, followed by a hydrosilylation reaction on the surface of hydrogen terminated SiNPs. Their physiochemical properties have been investigated by photoluminescence emission, Fourier transform infrared spectroscopy (FTIR) and elemental analysis. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay has been employed to evaluate in vitro toxicity in human colorectal adenocarcinoma (Caco-2) cells and human normal colon epithelial (CCD) cells. The results show significant toxicity of thiourea SiNPs after 72 h of incubation in the cancer cell line, and the toxicity is concentration dependent and saturated for concentrations above 100 μg/mL. Confocal microscopy images have demonstrated the internalization of thiourea-functionalized SiNPs inside the cells. Flow cytometry data has confirmed receptor-mediated targeting in cancer cells. This nanocomposite takes advantage of the epidermal growth factor receptor (EGFR) active targeting of the ligand in addition to the photoluminescence properties of SiNPs for bioimaging purposes. The results suggest that this novel nanosystem can be extrapolated for active targeting of the receptors that are overexpressed in cancer cells such as EGFR using the targeting characteristics of thiourea-functionalized SiNPs and therefore encourage further investigation and development of anticancer agents specifically exploiting the EGFR inhibitory activity of such nanoparticles.

Topics: Caco-2 Cells; Colonic Neoplasms; ErbB Receptors; Gene Expression Regulation, Neoplastic; Humans; Nanoparticles; Particle Size; Silicon; Spectroscopy, Fourier Transform Infrared; Surface Properties; Thiourea

Synthesis of new chiral thiourea derivatives (27 examples) as anticancer agents has been described. Three compound 7d (NSC code 761448/1), 7e1 (NSC code 767161/1), and 7e3 (NSC code 767160/1) were found to exhibit higher anticancer activity than 5-fluorouracil against Colon cancer, Melanoma, Ovarian cancer, and Breast cancer subpanels. The effect of stereochemistry of amino acid residues on the tumor growth inhibitory activity has also been studied.

Topics: Antineoplastic Agents; Cell Proliferation; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Molecular Conformation; Stereoisomerism; Structure-Activity Relationship; Thiourea

Inducible nitric oxide synthase (iNOS) is a potential target for the treatment of inflammation and cancer. Previously, we showed that the selective iNOS inhibitor S,S'-1,4-phenylenebis(1,2-ethanediyl)bis-isothiourea (PBIT) caused significant inhibition of colon carcinogenesis induced by azoxymethane (AOM), although it did not completely abrogate NO production due to the exogenous bioavailability of NO and NO generation by eNOS in tumor tissues. To create an iNOS-targeting molecule that may have additional benefits, a novel isosteric analog of PBIT, PBI-Se, was developed, in which sulfur was replaced with selenium. Chemopreventive efficacy of PBI-Se was evaluated in an AOM-induced rat colon carcinogenesis model using aberrant crypt foci (ACF) as the endpoint. At 7 weeks of age, rats (12/group) were fed the control diet (AIN 76A) and then colonic ACF were induced with two AOM treatments. Three days later, rats were fed diets containing PBI-Se (0-20 ppm) for 8 weeks, and then ACF were evaluated histopathologically. Dietary administration of 10 or 20 ppm of PBI-Se significantly suppressed AOM-induced total colonic ACF formation (32 or 41%, p<0.002-0.0003), and multi-crypt (4 or more) aberrant foci (29 or 47%, p<0.01-0.0004), respectively. The inhibition by PBI-Se was dose-dependent and was half the dose of PBIT for inhibiting total ACF in rats. Both PBIT and PBI-Se induced dose-dependent apoptosis in CaCo2 cells and caused a significant decrease in the cell cycle proteins cyclin D1 (70%, p<0.0001) and iNOS (99%, p<0.0001). Treatment with PBIT (30 and 60 µM) and PBI-Se (2 and 4  µM) significantly decreased the LPS-induced cytokine interleukin-6 level. Incorporation of selenium into the structure of PBIT provided the agent with additional novel cytotoxic and immunologic properties. Results from the in vitro and in vivo bioassays suggest that PBI-Se could be developed further for the prevention and treatment of colon cancer.

Topics: Aberrant Crypt Foci; Animals; Apoptosis; Azoxymethane; Caco-2 Cells; Cell Line, Tumor; Cell Proliferation; Chemoprevention; Colonic Neoplasms; Cyclin D1; Humans; Interleukin-6; Interleukin-8; Male; Nitric Oxide Synthase Type II; Rats; Rats, Inbred F344; Selenium Compounds; Thiourea

By means of liquid chromatography-electrospray ionization (LC-ESI) mass spectrometry two glucosinolates, glucoiberin and 3-hydroxy,4(α-L-rhamnopyranosyloxy) benzyl glucosinolate, were identified in the aqueous extract of Brassica oleraceae L var. italica. Further, two compounds were isolated after enzymatic hydrolysis of the aqueous extract by myrosinase, one of them was identified as 4-vinyl-3-pyrazolidinone. The second compound (sulphoraphane) 1-isothiocyanate-4-methyl-sulphinyl butane, converted to the most stable form of thiourea (sulphoraphane thiourea). The crude extract (80% alcohol extract) of broccoli florets was examined for cytotoxic activity against different human cancer cell lines, it showed good inhibition of colon cancer (IC(50) 3.88 µg/mL). On the other hand each of the successive extracts (petroleum ether, chloroform, ethyl acetate and ethanol) showed no significant cytotoxic activity. When myrosinase hydrolysate was tested for cytotoxic activity on the colon cancer cell line it showed very high activity - 95% lethality up to 0.78 µg/mL.

Topics: Antineoplastic Agents; Brassica; Cell Line, Tumor; Cell Survival; Chromatography, Liquid; Colonic Neoplasms; Flowers; Glucosinolates; Glycoside Hydrolases; Humans; Hydrolysis; Inhibitory Concentration 50; Isothiocyanates; Plant Extracts; Pyrazolones; Spectrometry, Mass, Electrospray Ionization; Sulfoxides; Thiourea

Thiourea derivatives (6a-e) were developed and screened for antitumor and anti-inflammatory activity. Most of the compounds exhibited growth inhibitory effects comparable to 5-fluorouracil in vitro against mammary (MCF-7 and MDA-MB 231) as well as colon (HT-29) carcinoma cells. They also showed stronger anti-inflammatory activity than ibuprofen in vivo in the xylene-induced ear swelling assay in mice.

Topics: Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Biological Assay; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Cyclization; Disease Models, Animal; Drug Design; Female; Humans; Inhibitory Concentration 50; Mice; Pyrimidines; Thiourea

Premature or stress-induced senescence is a major cellular response to chemotherapy in solid tumors and contributes to successful treatment. However, senescent tumor cells are resistant to apoptosis and may also reenter the cell cycle. We set out to find a means to specifically induce senescent tumor cells to undergo cell death and not to reenter the cell cycle that may have general application in cancer therapy.. We investigated the mechanisms regulating cell survival in drug-induced senescent tumor cells. Using immunofluorescence and flow cytometry-based techniques, we established the status of the ataxia telangiectasia mutated (ATM) signaling pathway in these cells. We assayed the requirement of ATM signaling and p21(CIP1) expression for survival in premature senescent tumor cells using pharmacologic inhibitors and antisense oligonucleotides.. The ATM/ATR (ATM- and Rad3-related) signaling pathway was found to be constitutively active in drug-induced senescent tumor cells. We found that blocking ATM/ATR signaling with pharmacologic inhibitors, including the novel ATM inhibitors KU55933 and CGK733, induced senescent breast, lung, and colon carcinoma cells to undergo cell death. We show that the mechanism of action of this effect is directly via p21(CIP1), which acts downstream of ATM. This is in contrast to the effects of ATM inhibitors on normal, untransformed senescent cells.. Blocking ATM and/or p21(CIP1) following initial treatment with a low dose of senescence-inducing chemotherapy is a potentially less toxic and highly specific treatment for carcinomas.

Topics: Ataxia Telangiectasia Mutated Proteins; Benzeneacetamides; Breast Neoplasms; Carcinoma; Cell Cycle; Cell Cycle Proteins; Cell Survival; Cellular Senescence; Colonic Neoplasms; Cyclin-Dependent Kinase Inhibitor p21; DNA Damage; DNA-Binding Proteins; Drug Evaluation, Preclinical; Gene Expression Regulation, Neoplastic; HCT116 Cells; Humans; Lung Neoplasms; Morpholines; Protein Serine-Threonine Kinases; Pyrones; Thiourea; Tumor Cells, Cultured; Tumor Suppressor Proteins

Malignant melanoma is the most deadly form of skin cancer due to its highly metastatic nature. Untargeted therapies are ineffective for treating metastatic disease, leading to the development of agents specifically inhibiting proteins or pathways deregulated in melanoma. The deregulation of inducible nitric oxide synthase (iNOS) is one such event occurring in melanoma, and is correlated with poor survival. Current iNOS inhibitors, such as PBIT [S,S'-1,4-phenylenebis(1,2-ethanediyl)bis-isothiourea], require high concentrations for clinical efficacy causing systemic toxicity. To develop more potent agents effective at significantly lower concentrations, a novel isosteric analogue of PBIT was synthesized, called PBISe [S,S'-1,4-phenylenebis(1,2-ethanediyl)bis-isoselenourea], in which sulfur was replaced with selenium. PBISe kills melanoma cells >10-fold more effectively than PBIT, and cultured cancer cells are 2- to 5-fold more sensitive than normal cells. Like PBIT, PBISe targets iNOS but also has new inhibitory properties acting as an Akt3 pathway inhibitor and mitogen-activated protein kinase (MAPK) cascade activator, which causes decreased cancer cell proliferation and increased apoptosis. Inhibition of cellular proliferation mediated by PBISe induced a G2-M phase cell cycle block linked to excessively high MAPK activity causing decreased cyclin D1 and increased p21 as well as p27 levels. PBISe promotes apoptosis by inhibiting Akt3 signaling, elevating cleaved caspase-3 and PARP levels. Compared with PBIT, PBISe reduced tumor development by 30% to 50% in mice inducing a 2-fold increase in apoptosis with negligible associated systemic toxicity. Collectively, these results suggest that PBISe is a potent chemotherapeutic agent with novel properties enabling the targeting of iNOS, Akt3, and MAPK signaling, thereby promoting melanoma cell apoptosis and inhibition of proliferation.

Topics: Animals; Antineoplastic Agents; Apoptosis; Caco-2 Cells; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Female; Humans; MAP Kinase Signaling System; Melanoma; Mice; Mice, Nude; Organoselenium Compounds; Phosphatidylinositol 3-Kinases; Skin Neoplasms; Thiourea; Time Factors; Urea

The design and development of synthetic small molecules to disrupt microtubule dynamics is an attractive therapeutic strategy for anticancer drug discovery research. Loss of clinical efficacy of many useful drugs due to drug resistance in tumor cells seems to be a major hurdle in this endeavor. Thus, a search for new chemical entities that bind tubulin, but neither are a substrate of efflux pump, P-glycoprotein 170/MDR1, nor cause undesired side effects, would potentially increase the therapeutic index in certain cancer treatments.. A high-content cell-based screen of a compound library led to the identification of a new class of compounds belonging to a thienopyrimidine series, which exhibited significant antitumor activities. On structure-activity relationship analysis, R-253 [N-cyclopropyl-2-(6-(3,5-dimethylphenyl)thieno[3,2-d]pyrimidin-4-yl)hydrazine carbothioamide] emerged as a potent antiproliferative agent (average EC(50), 20 nmol/L) when examined in a spectrum of tumor cell lines.. R-253 is structurally unique and destabilizes microtubules both in vivo and in vitro. Standard fluorescence-activated cell sorting and Western analyses revealed that the effect of R-253 on cell growth was associated with cell cycle arrest in mitosis, increased select G(2)-M checkpoint proteins, and apoptosis. On-target activity of R-253 on microtubules was further substantiated by immunofluorescence studies and selected counter assays. R-253 competed with fluorescent-labeled colchicine for binding to tubulin, indicating that its binding site on tubulin could be similar to that of colchicine. R-253 neither is a substrate of P-glycoprotein 170/MDR1 nor is cytotoxic to nondividing human hepatocytes.. Both biochemical and cellular mechanistic studies indicate that R-253 could become a promising new tubulin-binding drug candidate for treating various malignancies.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Bone Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Flow Cytometry; HeLa Cells; Humans; Lung Neoplasms; Microtubules; Molecular Weight; Osteosarcoma; Pyrimidines; Thiophenes; Thiourea

Inducible nitric oxide synthase (iNOS) is overexpressed in colonic tumors of humans and also in rats treated with a colon carcinogen. iNOS appear to regulate cyclooxygenase-2 (COX-2) expression and production of proinflammatory prostaglandins, which are known to play a key role in colon tumor development. Experiments were designed to study the inhibitory effects of S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea (PBIT) a selective iNOS-specific inhibitor, measured against formation of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF). Beginning at 5 weeks of age, male F344 rats were fed experimental diets containing 0 or 50 p.p.m. of PBIT, or 2000 p.p.m. of curcumin (non-specific iNOS inhibitor). One week later, rats were injected s.c. with AOM (15 mg/kg body wt, once weekly for 2 weeks). At 17 weeks of age, all rats were killed, colons were evaluated for ACF formation and colonic mucosa was assayed for isoforms of COX and NOS activities. Both COX and iNOS activities in colonic mucosa of the AOM-treated rats were significantly induced. Importantly, 50 p.p.m. PBIT suppressed AOM-induced colonic ACF formation to 58% (P < 0.0001) and crypt multiplicity containing four or more crypts per focus to 78% (P < 0.0001); it also suppressed AOM-induced iNOS activity. Curcumin inhibited colonic ACF formation by 45% (P < 0.001). These observations suggest that iNOS may play a key regulatory role in colon carcinogenesis. Developing iNOS-specific inhibitors may provide a selective and safe chemopreventive strategy for colon cancer treatment.

Topics: Animals; Anticarcinogenic Agents; Azoxymethane; Carcinogens; Colonic Diseases; Colonic Neoplasms; Curcumin; Cyclooxygenase 2; Enzyme Inhibitors; Intestinal Mucosa; Isoenzymes; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Precancerous Conditions; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Rats; Rats, Inbred F344; Thiourea

Certain aspects of the potentiation induced by 1-beta-D-arabinofuranosylcytosine (ara-C) on cis-diamminedichloroplatinum(II) (cis-DDP) cytotoxicity were investigated. The time dependency of additions of ara-C and cis-DDP was established by allowing cells to grow for various intervals in fresh medium following the removal of one agent before adding the second one. ara-C had no potentiating effect on cis-DDP toxicity when given to the cells before the addition of cis-DDP. When the experiment was reversed so that cis-DDP was added first and ara-C second, a slight potentiating effect was observed even if the drugs were added 4 h apart. The optimal toxic effect was obtained when ara-C and cis-DDP were added together. Continuous exposure of cells to concentrations of ara-C and cis-DDP 10 times lower than those used in pulse treatment experiments resulted in an additive rather than a synergistic effect. ara-C, unable to kill cells in pulse treatment, killed 96% of the cells after 24 h of continuous incubation. Thiourea was able to prevent the cytotoxic effect of cis-DDP in a concentration-dependent manner when given to the cells immediately following their treatment with cis-DDP; at 0.1 M thiourea, the cytotoxic effect of cis-DDP was almost completely prevented. Similar results were obtained when the cells were exposed to a combination of cis-DDP and ara-C. In this case, 0.1 M thiourea resulted in over 80% survival of cells treated with the drug combination. Thiourea had to be added to the cells either together with cis-DDP or immediately following removal of the drug in order to completely prevent the cytotoxic effect. A similar time factor was involved when cells were treated with a combination of cis-DDP and ara-C before their exposure to thiourea, but in this case thiourea was only able to prevent completely the cytotoxic effect when added simultaneously with the drug combination. In other experiments, the effect of thiourea on cis-DDP-induced DNA cross-linking was measured by the alkaline elution technique. Thiourea was capable of preventing DNA cross-link formation both in cells treated with cis-DDP alone, and in cells exposed to the combination of cis-DDP and ara-C These observations further support the contention that ara-C potentiates cis-DDP cytotoxicity by increasing the ability of the platinum compound to form earlier, more stable DNA cross-links regardless of whether it is present in free or monoadducted form.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Cell Line; Cell Survival; Cell-Free System; Cisplatin; Colonic Neoplasms; Cross-Linking Reagents; Cytarabine; DNA; DNA, Neoplasm; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Synergism; Humans; Kinetics; Thiourea

Cell proliferation in dimethylhydrazine-induced colonic carcinomata was stimulated by histamine and by the histamine H2 receptor agonist dimaprit and inhibited by the histamine H2 receptor antagonists Metiamide and Cimetidine but not by the histamine H1 receptor antagonist Mepyramine. In contrast histamine had no effect on colonic crypt cell proliferation in normal or dimethylhydrazine-treated rats.

Topics: Adenocarcinoma; Animals; Cell Division; Cimetidine; Colon; Colonic Neoplasms; Dimethylhydrazines; Histamine; Intestinal Mucosa; Male; Metiamide; Pyrilamine; Rats; Receptors, Histamine; Receptors, Histamine H2; Stimulation, Chemical; Thiourea