Discovery of novel phenoxazinone derivatives as DKK1/LRP6 interaction inhibitors: Synthesis,biological evaluation and structure–activity relationships

Amino derivatives of NCI8642 were synthesized and evaluated as inhibitors of DKK1/LRP6 interactions. The new inhibitors were able to activate the Wnt signaling pathway as indicated by the increased levels of β-catenin, and decrease the DKK1-induced Tau phosphorylation at serine 396.     

Immunologic significance of nonspecific suppressor cells in spleens of tumor-bearing mice.

Spleen cells from mice bearing a progressively growing syngeneic tumor failed to respond to stimulation with mitogens in vitro. This lack of reactivity was due to the presence of nylon wool-adherent cells in the population that could inhibit the mitogen response of normal lymphocytes. Paradoxically, at times when strong suppressor cell activity could be detected in tumor-bearing mice, the animals responded normally to in vivo immunization with sheep erythrocytes and allogeneic tumors, and to in vitro sensitization with allogeneic tumor cells. Regression of a highly antigenic syngeneic tumor also was unaffected by the presence of these suppressor cells. Thus, the occurrence of nonspecific suppressor cells in the spleens of tumor-bearing mice did not influence the overall immunologic competence of these animals.     

SIMEX for correction of dietary exposure effects with Box-Cox transformed data

Modelling dietary data, and especially 24-hr dietary recall (24HDR) data, is a challenge. Ignoring the inherent measurement error (ME) leads to biased effect estimates when the association between an exposure and an outcome is investigated. We propose an adapted simulation extrapolation (SIMEX) algorithm for modelling dietary exposures. For this purpose, we exploit the ME model of the NCI method where we assume the assumption of normally distributed errors of the reported intake on the Box-Cox transformed scale and of unbiased recalls on the original scale. According to the SIMEX algorithm, remeasurements of the observed data with additional ME are generated in order to estimate the association between the level of ME and the resulting effect estimate. Subsequently, this association is extrapolated to the case of zero ME to obtain the corrected estimate. We show that the proposed method fulfils the key property of the SIMEX approach, that is, that the MSE of the generated data will converge to zero if the ME variance converges to zero. Furthermore, the method is applied to real 24HDR data of the I.Family study to correct the effects of salt and alcohol intake on blood pressure. In a simulation study, the method is compared with the NCI method resulting in effect estimates with either smaller MSE or smaller bias in certain situations. In addition, we found our method to be more informative and easier to implement. Therefore, we conclude that the proposed method is useful to promote the dissemination of ME correction methods in nutritional epidemiology.     

Synthesis,antitumor activity and molecular docking study of some novel 3-benzyl-4(3H)quinazolinone analogues

A novel series of 3-benzyl-substituted-4(3H)-quinazolinones were designed, synthesized and evaluated for their in vitro antitumor activity. The results of this study demonstrated that 2-(3-benzyl-6-methyl-4-oxo-3,4-dihydroquinazolin-2-ylthio)-N-(3,4,5-trimethoxyphenyl)acetamide, 2-(3-benzyl-6,7-dimethoxy-4-oxo-3,4-dihydroquinazolin-2-ylthio)-N-(3,4,5-trimethoxyphenyl)acetamide and 3-(3-benzyl-6-methyl-4-oxo-3,4-dihydroquinazolin-2-ylthio)-N-(3,4,5-trimethoxyphenyl)-propanamide have shown amazing broad spectrum antitumor activity with mean GI₅₀ (10.47, 7.24 and 14.12?µM. respectively), and are nearly 1.5–3.0-fold more potent compared with the positive control 5-FU with mean GI₅₀, 22.60?µM. On the other hand, compounds 6 and 10 yielded selective activities toward CNS, renal and breast cancer cell lines, whereas compound 9 showed selective activities towards leukemia cell lines. Molecular docking methodology was performed for compounds 7 and 8 into ATP binding site of EGFR-TK which showed similar binding mode to erlotinib, while compound 11 into ATP binding site of B-RAF kinase inhibited the growth of melanoma cell lines through inhibition of B-RAF kinase, similar to PLX4032.     

Down-regulation of particulate protein kinase Cepsilon and up-regulation of nuclear activator protein-1 DNA binding in liver following in vivo exposure of B6C3F1 male mice to heptachlor epoxide

The effects of in vivo administration of the cyclodiene tumor promoter heptachlor epoxide on mouse liver protein kinase C were studied in male B6C3F1 mice by protein kinase C activity assays and Western blotting under conditions known to increase the incidence of hepatocellular carcinoma because protein kinase C is thought to be critical in phorbol ester-induced tumor promotion. Under these test conditions, 20 ppm dietary heptachlor epoxide for 1-20 days increased cytosolic and decreased particulate total protein kinase C activities, while 10 ppm had no effect. Further, total cytosolic and particulate protein kinase C activities were decreased within 1 hour by 10 mg/kg intraperitoneal (i.p.) heptachlor epoxide. Western blotting showed that conventional protein kinase Calpha and beta isoforms were unaffected by heptachlor epoxide. Particulate novel protein kinase Cepsilon, however, was selectively down-regulated by 1, 10, and 20 ppm dietary heptachlor epoxide, whereas the cytosolic isoform was decreased by 1 and 10 ppm heptachlor epoxide for 10 days. The high-dose treatment for 24 hours also decreased particulate novel protein kinase Cepsilon but increased the cytosolic titer. These results demonstrate that this isoform is unique in its sensitivity to heptachlor epoxide. Activator protein-1 DNA binding, a critical factor in tumor promotion, was substantially increased at 3 and 6 hours with 3.7 mg/kg (i.p.) heptachlor epoxide and at 3 and 10 days with 20 ppm dietary heptachlor epoxide. The effects of heptachlor epoxide on protein kinase C and activator protein-1 are similar to those caused by phorbol ester treatments and correlate well to heptachlor levels found to induce tumors in mice. However, heptachlor epoxide did not initially activate protein kinase C with in vivo treatments or with in vitro treatments of a plasma membrane fraction aimed at demonstrating direct activation, as has been shown for phorbol esters. The ability of heptachlor epoxide to down-regulate particulate novel protein kinase Cepsilon correlates to dosages used in in vivo tumor promotion studies. However, this may represent a negative feedback response rather than a causative effect.     

Further study on synthesis and evaluation of 3,16,20-polyoxygenated steroids of marine origin and their analogs as potent cytotoxic agents

A series of new polyoxygenated steroid derivatives with various steroid skeleton moieties were synthesized. Antitumor activity of the compounds against three tumor cell lines (Breast cancer MCF7, lung cancer NCI and oral cancer KB) were evaluated. Compounds with aromatic A ring of this series exhibited the most potent cytotoxicities in all tested cells. The absence of OH at C-16 or lack of cholesterol like side chain at C-20 in the steroid skeleton apparently result in decreased cytotoxicity. The compound became inactive when the side chain contains double bond at C-24-C-25. When hydroxyl group at C-3 was protected no cytotoxicities against MCF7 and NCI and considerable low cytotoxicity against KB cell lines were observed.     

Semisynthesis and in vitro anticancer activities of andrographolide analogues

The plant Andrographis paniculata found throughout Southeast Asia contains Andrographolide 1, a diterpenoid lactone, which has antitumour activities against in vitro and in vivo breast cancer models. In the present study, we report on the synthesis of andrographolide derivatives, 3,19-isopropylideneandrographolide (2), 14-acetyl-3,19-isopropylideneandrographolide (3) and 14-acetylandrographolide (4), and their in vitro antitumour activities against a 2-cell line panel consisting of MCF-7 (breast cancer cell line) and HCT-116 (colon cancer cell line). Compounds 2 and 4 were also screened at the US National Cancer Institute (NCI) for their activities against a panel of 60 human cancer cell lines derived from nine cancer types. Compound 2 was found to be selective towards leukaemia and colon cancer cells, and compound 4 was selective towards leukaemia, ovarian and renal cancer cells at all the dose-response parameters. Compounds 2 and 4 showed non-specific phase of the cell cycle arrest in MCF-7 cells treated at different intervals with different concentrations. NCI's COMPARE and SOM mechanistic analyses indicated that the anticancer activities of these new class of compounds were not similar to that of standard anticancer agents, suggesting novel mechanism(s) of action.     

Synthesis and anticancer activity of novel bisindolylhydroxymaleimide derivatives with potent GSK-3 kinase inhibition

Synthesis and biological evaluation of a series of novel indole derivatives as anticancer agents is described. A bisindolylmaleimide template has been derived as a versatile pharmacophore with which to pursue chemical diversification. Starting from maleimide, the introduction of an oxygen to the headgroup (hydroxymaleimide) was initially investigated and the bioactivity assessed by screening of kinase inhibitory activity, identifying substituent derived selectivity. Extension of the hydroxymaleimide template to incorporate substitution of the indole nitrogens was next completed and assessed again by kinase inhibition identifying unique selectivity patterns with respect to GSK-3 and CDK kinases. Subsequently, the anticancer activity of bisindolylmaleimides were assessed using the NCI-60 cell screen, disclosing the discovery of growth inhibitory profiles towards a number of cell lines, such as SNB-75 CNS cancer, A498 and UO-31 renal, MDA MB435 melanoma and a panel of leukemia cell lines. The potential for selective kinase inhibition by modulation of this template is evident and will inform future selective clinical candidates.