Synthesis and biological evaluation of nitric oxide-donating analogues of sulindac for prostate cancer treatment

A series of analogues of the non-steroidal anti-inflammatory drug (NSAID) sulindac 1 were synthesised tethered to nitric oxide (NO) donating functional groups. Sulindac shows antiproliterative effects against immortal PC3 cell lines. It was previously demonstrated that the effect can be enhanced when tethered to NO releasing groups such as nitrate esters, furoxans and sydnonimines. To explore this approach further, a total of fifty-six sulindac–NO analogues were prepared and they were evaluated as NO-releasing cytotoxic agents against prostate cancer (PCa) cell lines. Compounds 1k and 1n exhibited significant cytotoxic with IC₅₀ values of 6.1 ± 4.1 and 12.1 ± 3.2 μM, respectively, coupled with observed nitric oxide release.     

New antifungal scaffold derived from a natural pharmacophore: Synthesis of α-methylene-γ-butyrolactone derivatives and their antifungal activity against Colletotrichum lagenarium

Thirty new and thirty-four known analogues were designed and synthesized to improve the potential use of the α-methylene-γ-butyrolactone ring, a natural pharmacophore. All structures were confirmed by ¹H and ¹³C NMR, MS, and single-crystal X-ray diffraction analyses. The results of antifungal and cytotoxic activity indicated that the synthesized analogues showed significant inhibitory activity and limited selectivity. Compound 45 exhibited the highest antifungal activity with IC₅₀ = 22.8 μM but moderate cytotoxic activity with IC₅₀ = 28.5 μM (against BGC823 cell line) and 7.7 μM (against HeLa cell line). Analysis of structure–activity relationships revealed that the incorporation of an aromatic ring into the β, γ positions of the lactone ring improved antifungal activity, and that the introduction of electron-withdrawing groups into the aromatic rings increased the activity compared with electron-donating groups. The above results identified 4-phenyl-3-phenyl-2-methylenebutyrolactone (33) as a lead scaffold for discovering and developing novel and improved crop-protection agents.     

Extended rhodamine photosensitizers for photodynamic therapy of cancer cells

Extended thio- and selenorhodamines with a linear or angular fused benzo group were prepared. The absorption maxima for these compounds fell between 640 and 700 nm. The extended rhodamines were evaluated for their potential as photosensitizers for photodynamic therapy in Colo-26 cells. These compounds were examined for their photophysical properties (absorption, fluorescence, and ability to generate singlet oxygen), for their dark and phototoxicity toward Colo-26 cells, and for their co-localization with mitochondrial-specific agents in Colo-26 and HUT-78 cells. The angular extended rhodamines were effective photosensitizers toward Colo-26 cells with 1.0 J cm⁻² laser light delivered at λ_max ± 2 nm with values of EC₅₀ of (2.8 ± 0.4) × 10⁻⁷ M for sulfur-containing analogue 6-S and (6.4 ± 0.4) × 10⁻⁸ M for selenium-containing analogue 6-Se. The linear extended rhodamines were effective photosensitizers toward Colo-26 cells with 5 and 10 J cm⁻² of broad-band light (EC₅₀’s ⩽ 2.4 × 10⁻⁷ M).     

Synthesis and biological evaluation of fluoro analogues of antimitotic phenstatin

With the aim of investigating the influence of fluorine, in particular on the A-ring, a new series of fluoro analogues (7a–l) of phenstatin (3) was synthesized and tested for interactions with tubulin polymerization and evaluated for cytotoxicity on an NCI-60 human cancer cell lines panel. We have shown that the replacement of 3,4,5-trimethoxyphenyl A-ring of phenstatin with 2,4,5-trifluoro-3-methoxyphenyl unit, results in the conservation of both antitubulin and cytotoxic effect. Fluoro isocombretastatin 7k was the most effective anticancer agent in the present study and demonstrated the highest antiproliferative potential on leukemia cell lines SR (GI₅₀ = 15 nM) and HL-60(TB) (GI₅₀ = 23 nM) and on melanoma cell line MDA-MB-435 (GI₅₀ = 19 nM).     

DNA binding acridine–thiazolidinone agents affecting intracellular glutathione

Three new acridine–thiazolidinone derivatives (2a–2c) have been synthesized and their interactions with calf thymus DNA and a number of cell lines (leukemic cells HL-60 and L1210 and human epithelial ovarian cancer cell lines A2780) were studied. The compounds 2a–2c possessed high affinity to calf thymus DNA and their binding constants determined by spectrofluorimetry were in the range of 1.37 × 10⁶–5.89 × 10⁶ M^?1. All of the tested derivatives displayed strong cytotoxic activity in vitro, the highest activity in cytotoxic tests was found for 2c with IC₅₀ = 1.3 ± 0.2 μM (HL-60), 3.1 ± 0.4 μM (L1210), and 7.7 ± 0.5 μM (A2780) after 72 h incubation. The cancer cells accumulated acridine derivatives very fast and the changes of the glutathione level were confirmed. The compounds inhibited proliferation of the cells and induced an arrest of the cell cycle and cell death. Their influence upon cells was associated with their reactivity towards thiols and DNA binding activity.     

Synthesis and cytotoxicities of icogenin analogues with disaccharide residues

For further structure–activity relationships (SAR) research of furostan saponin, two icogenin analogues: (25R)-22-O-methyl-furost-5-en-3β,26-diol-3-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside 1 and (25R)-22-O-methyl-furost-5-en-3β,26-diol-3-O-α-l-rhamnopyranosyl-(1 → 2)-α-d-glucopyranoside 2, with valuable disaccharide moieties, were synthesized from diosgenin through eight steps. Both of the analogues behaved the similar cytotoxic activities with icogenin, towards nine types of human tumor cells herein.     

Antiproliferative,antiandrogenic and cytotoxic effects of novel caffeic acid derivatives in LNCaP human androgen-dependent prostate cancer cells

Caffeic acid and its naturally occurring derivative caffeic acid phenethyl ester (CAPE) have antiproliferative and cytotoxic properties in a variety of cancer cell lines without displaying significant toxicity toward healthy cells, and are considered to be potential anticancer agents. However, little is known about their effects on prostate cancer cells. We synthesized and evaluated the effects of caffeic acid, CAPE (2) and 18 synthetic derivatives on cell viability and androgen-dependent cell proliferation, subcellular localisation and expression of androgen receptor (AR) and secretion of prostate-specific antigen (PSA) in LNCaP human hormone-dependent prostate cancer cells. Several synthetic derivatives of CAPE were strong, concentration-dependent cytotoxic agents in LNCaP cells with IC₅₀ values in the 6.8–26.6 μM range, potencies that were up to five-fold greater than that of CAPE (33.7 ± 4.0 μM). A number of caffeic acid derivatives were inhibitors of androgen-stimulated LNCaP cell proliferation with concomitant inhibition of DHT-stimulated PSA secretion. Compound 24 was the most cytotoxic and antiproliferative caffeic acid derivative (IC₅₀ values of 6.8 ± 0.3 and 2.4 ± 0.8 μM, respectively) inhibiting DHT-stimulated cell proliferation and PSA secretion statistically significantly at concentrations as low as 0.3 μM. Exposure to DHT increased cytoplasmic and nuclear AR levels and co-treatment with increasing concentrations of compound 24 or CAPE (2), notably, further increased these levels. In conclusion, a number of synthetic derivatives of caffeic acid are potent inhibitors of androgen-dependent prostate cancer cell proliferation and viability, acting, at least in part, via an antiandrogenic mechanism that involves increased nuclear accumulation of (presumably inactive) AR.     

Adverse events following infusion of T cells for adoptive immunotherapy: a 10-year experience

Background aimsThe Food and Drug Administration (FDA) currently recommends at least 4 h of recipient monitoring after T cell infusions to detect early infusion reactions. Recent catastrophic reactions to ‘first-in-man’ biologic agents have emphasized the importance of this rule for initial studies of new products. The value of such monitoring for better established agents is less obvious.MethodsWe reviewed infusion-related adverse events (AE) following administration of ex vivo-expanded T cell products (antigen-specific cytotoxic T lymphocytes, allodepleted T cells, and genetically modified T cells) on investigational new drug (IND) studies in our center.ResultsFrom 1998 to 2008, we infused 381 T cell products to 180 recipients, enrolled on 18 studies, receiving T cells targeting malignancies or post-transplant viral infections. There were no grade 3–4 infusion reactions during initial monitoring or 24-h follow-up. Twenty-four mild (grade 1–2) AE occurred in 21 infusions either during or immediately following infusion (up to 6 h), most commonly nausea and vomiting (10/24, 41.6%), probably because of the dimethyl sulfoxide cryoprotectant, and hypotension (20.8%), attributable to diphenhydramine pre-medication. Twenty-two additional non-severe events were reported within 24 h of infusion, most commonly culture-negative fever, chills and nausea. An increased risk of adverse events was associated with age [incidence rate ratio (IRR) 0.98; 95% confidence interval (CI) 0.96–1.00, P = 0.05], while an increased risk of immediate infusion-related events was higher in patients reporting allergies (IRR 2.72, 95% CI 1.00–7.40, P = 0.05); sex, disease type and T cell source (allogeneic or autologous) had no effect on frequency of adverse events.ConclusionsInfusion of these T cell products was safe in the outpatient setting and associated with no severe reactions, so monitoring for 1 h after infusion is probably sufficient. As many of the AE were attributable to diphenhydramine premedication, a lower dose (0.25 mg/kg) should be selected.     

Endothelial permeability in vitro and in vivo: Protective actions of ANP and omapatrilat in experimental atherosclerosis

Increased arterial endothelial cell permeability (ECP) is considered an initial step in atherosclerosis. Atrial natriuretic peptide (ANP) which is rapidly degraded by neprilysin (NEP) may reduce injury-induced endothelial cell leakiness. Omapatrilat represents a first in class of pharmacological agents which inhibits both NEP and angiotensin converting enzyme (ACE). We hypothesized that ANP prevents thrombin-induced increases of ECP in human aortic ECs (HAECs) and that omapatrilat would reduce aortic leakiness and atherogenesis and enhance ANP mediated vasorelaxation of isolated aortas. Thrombin induced ECP determined by I¹²⁵ albumin flux was assessed in HAECs with and without ANP pretreatment. Next we examined the effects of chronic oral administration of omapatrilat (12 mg/kg/day, n = 13) or placebo (n = 13) for 8 weeks on aortic leakiness, atherogenesis and ANP-mediated vasorelaxation in isolated aortas in a rabbit model of atherosclerosis produced by high cholesterol diet. In HAECs, thrombin-induced increases in ECP were prevented by ANP. Omapatrilat reduced the area of increased aortic leakiness determined by Evans-blue dye and area of atheroma formation assessed by Oil-Red staining compared to placebo. In isolated arterial rings, omapatrilat enhanced vasorelaxation to ANP compared to placebo with and without the endothelium. ANP prevents thrombin-induced increases in ECP in HAECs. Chronic oral administration of omapatrilat reduces aortic leakiness and atheroma formation with enhanced endothelial independent vasorelaxation to ANP. These studies support the therapeutic potential of dual inhibition of NEP and ACE in the prevention of increased arterial ECP and atherogenesis which may be linked to the ANP/cGMP system.     

Synthesis of N-Mannich bases of berberine linking piperazine moieties revealing anticancer and antioxidant effects

A new Mannich base series of piperazine linked berberine analogues was furnished in this study to screen the antioxidant and anticancer potential of the resultant analogues. Alkoxy group at a C-9 position of berberine was converted to hydroxyl functionality to enhance the ability of final scaffolds binding to the target of drug action mainly through hydrophobic effect, conjugation effect, whereas Mannich base functionality was introduced on the C-12 position of berberine. Scaffolds were investigated for their free radical scavenging antioxidant potential in FRAP and DPPH assay, whereas tested to check their Fe⁺³ reducing power in ABTS assay. The radical scavenging potential of the final derivatives 4a–j was found excellent with IC₅₀s, <13 μg/mL and < 8 μg/mL in DPPH and ABTS assay, respectively, whereas some analogues showed significant Fe⁺³ reducing power with absorption at around 2 nm in the FRAP assay. Anticancer effects of titled compounds were inspected against cervical cancer cell line Hela and Caski adapting SRB assay, in which analogues 4a–j presented <6 μg/mL of IC₅₀s, and >30 of therapeutic indices, thus exerting low cytotoxic values against Malin–Darby canine kidney (MDCK) cell lines at CC₅₀s >125 μg/mL. Hence, from the bioassay outcomes it can be stated that these analogues are dual active agents as the scavengers of reactive oxygen species and inhibitors of the cancerous cells as compounds with halogen functional group have overall good pharmacological potential in assays studied in this research. Correct structure of the final compounds was adequately confirmed on the basis of FT-IR and ¹H NMR as well as elemental analyses.     

Synthesis of a second generation chroman/catechol hybrids and evaluation of their activity in protecting neuronal cells from oxidative stress-induced cell death

A new generation of chroman/catechol hybrids bearing heterocyclic five-membered rings, such as 1,2,4-oxadiazole 1,3,4-oxadiazole, 1,2,3-triazole, tetrazole and isoxazole, were designed and synthesized. The activity of the new derivatives against oxidative stress induced neuronal damage, was evaluated using glutamate-challenged hippocampal HT22 cells.Compound 3 in which a 3,4-dimethoxyphenyl moiety, is directly attached to the 1,2,4-oxadiazole ring was the most active among the 2-substituted chroman analogues, with EC₅₀ = 254 ± 65 nM. Concerning the 5-subtituted chroman analogues, isoxazole derivative 29 exhibited the strongest activity (EC₅₀ = 245 ± 38 nM). However, 29 was cytotoxic at concentrations higher than 1 μM, while the triazole analogue 24 (EC₅₀ = 801 ± 229 nM), was non-toxic at all concentrations tested.     

Interleukin-21 restrains tumor growth and induces a substantial increase in the number of circulating tumor-specific T cells in a murine model of malignant melanoma

New strategies of immunotherapy are currently being evaluated, and the combination of chemo- and immunotherapy has shown promising results. The cytokine interleukin-21 (IL-21) is known to enhance immune function, and in this study we have investigated its ability to boost the efficacy of chemoimmunotherapy—cyclophosphamide and adoptive cell transfer (ACT)—in the B16-OVA/OT-I murine model of malignant melanoma. Subcutaneous B16-OVA tumors were established in C57BL/6J mice 8 days before adoptive transfer of tumor-specific OT-I T cells. In addition to cyclophosphamide and ACT, one group of mice received daily injections of murine IL-21 (mIL-21). Mice treated with mIL-21 had more tumor-specific T cells in the circulation 4 and 7 days following ACT (P = 0.004 and P = 0.002, respectively). Importantly, mIL-21 and ACT controlled tumor growth instantly and more effectively than ACT alone (P = 0.001, day 4)—an effect that persisted up to 5 days after the last mIL-21 injection. We conclude that mIL-21 enhances chemoimmunotherapy: it amplifies the number of tumor-specific T cells in the circulation and also stunts early tumor growth.     

Design,synthesis, and quantitative structure–activity relationship of cytotoxic γ-carboline derivatives

Three series of γ-carboline derivatives were designed and synthesized. All the compounds were tested for their cytotoxic activities in vitro against five human tumor cell lines (A549, SGC, HCT116, MCF-7, K562) and one multi-drug resistant subline (K562R). Most compounds showed moderate to potent cytotoxic activities against the tested cell lines. Sulfonate 11f exhibited more potent cytotoxic activities against almost all of the tested cells in comparison with the positive control, taxol, with IC₅₀ values ranging from 0.15 to 4.5 μM. The structure–activity relationships were discussed and a statistically reliable QSAR model (r² = 0.936, q² = 0.581) was established by the CoMFA analysis performed using the cytotoxic data against K562 cell line as a template.     

Characterization of anticancer properties of 2,6-diisopropylphenol–docosahexaenoate and analogues in breast cancer cells

The present study describes the characterization and evaluation of novel anticancer conjugates, 2,6-diisopropylphenol–docosahexaenoate (PP–DHA), and its analogues including 2,4-diisopropylphenol–docosahexaenoate (DIPP–DHA), 2-isopropylphenol–docosahexaenoate (IPP–DHA), 2-cyclohexanephenol-docosahexaenoate (CHP–DHA) and phenol–docosahexaenoate (P–DHA) on breast cancer cell lines. Representative breast cancer cell lines, based on estrogen α receptor (ER) and oncogene Her-2 expression, were used and include MDA-MB-231 (ER-negative, Her-2-negative), MCF-7 (ER-positive, Her-2-negative) AU565 (ER-negative, Her-2-positive) and MDA-MB-361 (ER-positive, Her-2-positive). The PP–DHA conjugate significantly inhibited cell growth and induced cell loss in the breast cancer cell lines similarly; however, this conjugate was not effective against normal mammary epithelial cells. The effect of various conjugates were in PP–DHA > IPP–DHA > DIPP–DHA > CHP–DHA >> P–DHA order. PP–DHA and IPP–DHA conjugates were stable in human and mouse serum. Furthermore, the non-hydrolyzable amide-linked conjugate analogues affected breast cancer cells in a manner similar to that of the ester-linked conjugates. This suggests that ester-linked PP–DHA and IPP–DHA conjugates were stable during treatment to breast cancer cells due to structural hindrance. PP–DHA did not affect PPARα or PPARγ activities but its anticancer effects appear to be mediated in part though the inhibition of histone deacetylase (HDAC) activity. Further experiments are needed to confirm their molecular target and to test the effectiveness of these compounds in an in vivo model for their anticancer properties. In conclusion, these results suggest that the novel PP–DHA and IPP–DHA conjugates and their amide derivatives may be useful for the treatment of breast cancer.     

Synthesis and biological evaluation of azole-diphenylpyrimidine derivatives (AzDPPYs) as potent T790M mutant form of epidermal growth factor receptor inhibitors

A series of novel azole-diphenylpyrimidine derivatives (AzDPPYs) were synthesized and biologically evaluated as potent EGFR^T790M inhibitors. Among these analogues, the most active inhibitor 6e not only displayed high activity against EGFR^T790M/L858R kinase (IC₅₀ = 3.3 nM), but also was able to repress the replication of H1975 cells harboring EGFR^T790M mutation at a concentration of 0.118 μmol/L. In contrast to the lead compound rociletinib, 6e slightly reduces the key EGFRT790M-minduced drug resistance. Significantly, inhibitor 6e demonstrates high selectivity (SI = 299.3) for T790M-containing EGFR mutants over wild type EGFR, hinting that it will cause less side effects.     

Discovery and structure–activity relationship studies of quinolinone derivatives as potent IL-2 suppressive agents

The quinolinone skeleton has been utilized to develop various mechanism-based immune modulators. However, the effects of quinolinone derivatives on the release of T cell-associated interleukin-2 (IL-2) have not been established. In this study, a series of novel quinolinone derivatives was synthesized, and their immunosuppressive activity was evaluated by measuring suppression of IL-2 release from activated Jurkat T cells. Optimizing the three side chains around the quinolinone skeleton revealed the most active compound: 11l. This compound exhibits potent inhibitory activity toward IL-2 release in both 12-o-tetradecanoylphorbol-13-acetate (PMA)/A23187 (ionomycin) (IC₅₀ = 80 ± 10 nM) and anti-CD3/CD28-stimulated Jurkat T cells (83% inhibition at 10 μM) without cytotoxic effects. Further investigation into the underlying mechanism of 11l indicated the suppression of NF-κB and nuclear factor of activated T cells (NFAT) promoter activities in Jurkat T cells.     

Chalcones,inhibitors for topoisomerase I and cathepsin B and L,as potential anti-cancer agents

In order to diversify the pharmacological activity of chalcones and extend the scaffold of topoisomerase and cathepsins B and L inhibitors, we have designed and synthesized total 18 chalcone compounds and tested their biological activity. In the topoisomerase inhibition test, most analogues in group III and IV except compound 11 exhibited more efficient topoisomerase I inhibitory activity than camptothecin at 20 μM. Compounds 15, 16 and 18 in group IV showed significant cathepsin B and L inhibitory activity. Among the compounds, compound 15 was most active with IC₅₀ values of 1.81 ± 0.05 μM on cathepsin B and 3.15 ± 0.07 μM on cathepsin L, respectively. Compound 15 also showed most potent cytotoxic activity against T47D and SNU638 cells with IC₅₀ values of 1.37 ± 0.05 μM and 0.62 ± 0.01 μM, respectively. Overall, although more compounds should be tested and analyzed for clear SAR against topoisomerase I and cathepsin B and L, compound 15 showed consistent inhibitory ability on the tested assays, which can implicate the cytotoxic activity of compound 15 on topoisomerase I and cathepsin B and L inhibitory pathways.     

Spirostanols from the roots and rhizomes of Trillium tschonoskii

Two novel spirostanols, (23S,24R,25S)-18-norspirost-1,4,13-triene-21,23,24-triol-3,15-dione (1) and (23S,24S,25S)-spirost-5-ene-1β,3β,21,23,24-pentaol (2), a new natural product (3), and two known analogues (4 and 5) were isolated from the ethyl acetate-soluble portion of the ethanolic extract of Trillium tschonoskii Maxim. Their structures were elucidated by extensive spectroscopic analyses, and their cytotoxic activities on four kinds of human tumor cells were studied in vitro. Compound 4 showed significant cytotoxic activity against MCF-7 and A549 with IC₅₀ values of 6.16 ± 2.21 and 28.5 ± 11.5 μM, respectively, while 5 exhibited selective cytotoxicity against A549 with an IC₅₀ value of 13.0 ± 4.51 μM.     

Design,synthesis and biological evaluation of N-arylphenyl-2,2-dichloroacetamide analogues as anti-cancer agents

Our earlier research has shown that N-phenyl-2,2-dichloroacetamide analogues had much higher anti-cancer activity than the lead compound sodium dichloroacetate (DCA). In this current study, a variety of N-arylphenyl-2,2-dichloroacetamide analogues were synthesized via Suzuki coupling reaction and their anti-cancer activity was evaluated. The results showed that N-terphenyl-2,2-dichloroacetamide analogues had satisfactory anti-cancer activity. Among them, N-(3,5-bis(benzo[d][1,3]dioxol-5-yl)phenyl)-2,2-dichloroacetamide (6 k) had an IC₅₀ of 2.40 μM against KB-3-1 cells, 1.04 μM against H460 cells and 1.73 μM against A549 cells.     

Design,synthesis and cytotoxic activity of novel sulfonylurea derivatives of podophyllotoxin

Three series of novel sulfonylurea podophyllotoxin derivatives were designed, synthesized, and evaluated for in vitro cytotoxicity against four tumor cell lines (A-549, DU-145, KB and KBvin). Compounds 14c (IC₅₀: 1.41–1.76 μM) and 14e (IC₅₀: 1.72–2.01 μM) showed superior cytotoxic activity compared with etoposide (IC₅₀: 2.03 to >20 μM), a clinically available anticancer drug. Significantly, most of the compounds exhibited comparable cytotoxicity against the drug-resistant tumor cell line KBvin, while etoposide lost activity completely. Preliminary structure–activity relationship (SAR) correlations indicated that the 4′-O-methyl functionality in podophyllotoxin analogues may be essential to maintain cytotoxic activity, while an arylsulfonylurea side chain at podophyllotoxin’s 4β position can significantly improve cytotoxic activity.