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Two series of novel unsymmetrical 3,5-bis(benzylidene)-4 piperidones 2a - f and 3a - e were designed as candidate antineoplastic agents. These compounds display potent cytotoxicity towards two colon cancers, as well as several oral squamous cell carcinomas. These compounds are less toxic to various non-malignant cells giving rise to large selectivity index (SI) figures. Many of the compounds are also cytotoxic towards CEM lymphoma and HL-60 leukemia cells. Representative compounds induced apoptotic cell death characterized by caspase-3 activation and subG1 accumulation in some OSCC cells, as well as the depolarization of the mitochondrial membrane potential in CEM cells. A further line of inquiry was directed to finding if the SI values are correlated with the atomic charges on the olefinic carbon atoms. The potential of these compounds as antineoplastic agents was enhanced by an ADME (absorption, distribution, metabolism, and excretion) evaluation of five lead molecules, which revealed no violations.

Background: Very few papers covering the anticancer activity of azulenes have been reported, as compared with those of antibacterial and anti-inflammatory activity. This led us to investigate the antitumor potential of fifteen 4,6,8-trimethyl azulene amide derivatives against oral malignant cells., Methods: 4,6,8-Trimethyl azulene amide derivatives were newly synthesized. Anticancer activity was evaluated by tumor-specificity against four human oral squamous cell carcinoma (OSCC) cell lines over three normal oral cells. Neurotoxicity was evaluated by cytotoxicity against three neuronal cell lines over normal oral cells. Apoptosis induction was evaluated by Western blot and cell cycle analyses., Results: Among fifteen derivatives, compounds 7 , 9 , and 15 showed the highest anticancer activity, and relatively lower neurotoxicity than doxorubicin, 5-fluorouracil (5-FU), and melphalan. They induced the accumulation of a comparable amount of a subG 1 population, but slightly lower extent of caspase activation, as compared with actinomycin D, used as an apoptosis inducer. The quantitative structure-activity relationship analysis suggests the significant correlation of tumor-specificity with a 3D shape of molecules, and possible involvement of inflammation and hormone receptor response pathways., Conclusions: Compounds 7 and 15 can be potential candidates of a lead compound for developing novel anticancer drugs.

Nilotinib is used as standard treatment in managing chronic myeloid leukaemia (CML). A 23-year-old man with CML and on nilotinib was admitted to the intensive care unit due to respiratory failure. Three years prior, he developed pleural effusion from dasatinib therapy thus, his CML regimen was changed to nilotinib. Although the pleural effusion had once improved, the chest imaging revealed left-dominant bilateral pleural effusion. Endotracheal intubation and left thoracic drainage were performed. Nilotinib treatment was discontinued, and approximately 60 hours later, nilotinib concentrations of 927 and 2092 ng/mL were determined in his blood and pleural effusion, respectively. Severe pleural effusion may be induced in patients administering nilotinib, and nilotinib concentrations in blood and pleural effusion can be elevated in patients with nilotinib-related pleural effusion. Cross-occurrence of pleural effusions needs to be monitored precisely, especially in patients who are switched to other tyrosine kinase inhibitors after dasatinib treatment., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Cancer stem cells (CSCs) are believed to cause cancer metastasis and recurrence. BEX2 (brain expressed X-linked gene 2) is a CSC-related gene that is expressed in dormant CSCs in cholangiocarcinoma and induces resistance against chemotherapy. The aim of the present study was to identify small compounds that have activity to inhibit BEX2 expression and result in the attenuation of CSC-related phenotypes. We screened 9600 small chemical compounds in high-throughput screening using cholangiocarcinoma cell line HuCCT1 expressing BEX2 protein fused with NanoLuc, and identified a compound, BMPP (1, 3-Benzenediol, [4-(4-methoxyphenyl)-1H-pyrazol-3-yl]). BMPP was found to exert decreasing effects on BEX2 protein expression and G 0 phase population of the tumor cells, and increasing effects on ATP levels and chemotherapeutic sensitivity of the cells. These findings indicate that BMPP is a valuable chemical compound for reducing dormant CSC-related phenotypes. Thus, the identification of BMPP as a potential CSC suppressor provides scope for the development of novel therapeutic modalities for the treatment of cancers with BEX2 overexpressing CSCs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Inc.)

Purpose Anorexia induced by cytotoxic chemotherapy on delayed phase is a highly frequent adverse event. We aimed to determine the effects of rikkunshito (RKT) on chemotherapy-induced anorexia (CIA) in patients with lung cancer. Methods This prospective, randomized, cross-over pilot trial included 40 lung cancer patients scheduled to undergo cisplatin-based chemotherapy and randomized to either a group given RKT 7.5 g/day for 14 days (Group A, N = 20) or not (Group B, N = 20), then the treatments were switched. All patients received dexamethasone, palonosetron hydrochloride and aprepitant regardless of group assignment. Rescue drugs were allowed as required. The primary and key secondary endpoints were changes in caloric intake and in plasma acylated ghrelin (AG) levels, respectively. Average daily caloric intake during days 3 to 5 was compared with that on day 1 of each course. Results The primary and key secondary endpoints were analyzed in 31 patients (per protocol population) completing the study. Reduction rate of caloric intake was lower in RKT, than in control courses (18% vs. 25%, P = 0.025). Plasma AG levels significantly declined between days 1 and 3 in RKT (12.3 vs. 7.5 fmol/mL, P < 0.001) and control (10.8 vs. 8.6 fmol/mL, P < 0.001) courses. However, those obviously increased to 8.5 fmol/mL (P = 0.025) by day 5 in RKT course but not in control course (7.7 fmol/mL, P = 0.28). Conclusions Rikkunshito could mitigate CIA and ameliorate plasma AG levels during the delayed phase of CDDP-based chemotherapy in lung cancer patients. Clinical trial registration numbers: UMIN000010748.

Essentials We generated recombinant rhodocytin that could aggregate platelets via CLEC-2. Recombinant wild-type rhodocytin formed heterooctamer with four α- and β-subunits. Asp 4 in α-subunit of rhodocytin was required for binding to CLEC-2. Inhibitory mutant of rhodocytin blocked podoplanin-dependent hematogenous metastasis., Summary: Background Rhodocytin, a disulfide-linked heterodimeric C-type lectin from Calloselasma rhodostoma consisting of α-subunits and β-subunits, induces platelet aggregation through C-type lectin-like receptor 2 (CLEC-2). CLEC-2 is a physiological binding partner of podoplanin (PDPN), which is expressed on some tumor cell types, and is involved in tumor cell-induced platelet aggregation and tumor metastasis. Thus, modified rhodocytin may be a possible source of anti-CLEC-2 drugs for both antiplatelet and antimetastasis therapy. However, its molecular function has not been well characterized, because of the lack of recombinant rhodocytin that induces platelet aggregation. Objective To produce recombinant rhodocytin, in order to verify its function with mutagenesis, and to develop an anti-CLEC-2 drug based on the findings. Methods We used Chinese hamster ovary cells to express recombinant rhodocytin (wild-type [WT] and mutant), which was analyzed for induction/inhibition of platelet aggregation with light transmission aggregometry, the formation of multimers with blue native PAGE, and binding to CLEC-2 with flow cytometry. Finally, we investigated whether mutant rhodocytin could suppress PDPN-induced metastasis in an experimental lung metastasis mouse model. Results Functional WT] rhodocytin (αWTβWT) was obtained by coexpression of both subunits. Asp4 in α-subunits of rhodocytin was required for CLEC-2 binding. αWTβWT formed a heterooctamer similarly to native rhodocytin. Moreover, an inhibitory mutant of rhodocytin (αWTβK53A/R56A), forming a heterotetramer, bound to CLEC-2 without inducing platelet aggregation, and blocked CLEC-2-PDPN interaction-dependent platelet aggregation and experimental lung metastasis. Conclusion These findings provide molecular characterization information on rhodocytin, and suggest that mutant rhodocytin could be used as a therapeutic agent to target CLEC-2., (© 2018 International Society on Thrombosis and Haemostasis.)

Introduction: Sixty years since its introduction, 5-FU still forms the core of chemotherapy regimens for many types of malignancies. 5-FU is a time-dependent drug but is rapidly degraded in plasma by dihydropyrimidine dehydrogenase (DPD). Although originally developed in an intravenous form, 5-FU oral prodrugs were developed with the goal of improving efficacy and minimizing toxicity as well as to capitalize on the advantages of oral drug administration. The inactive 5-FU prodrug is gradually converted into the active form in the systemic circulation. UFT, S-1, and capecitabine are oral 5-FU prodrugs currently in clinical use. However, the efficacy of 5-FU can be further improved by its combination with DPD inhibitors and biochemical modulators, such as uracil and leucovorin, in addition to modifying administration schedules. Areas covered: We focused on the drug delivery of oral 5-FU prodrugs, their pharmacokinetics, and the development of DPD inhibitors. Since oral 5-FU prodrugs have been formulated into combination drugs, we also discussed the regulatory approval of combination drugs. Expert opinion: Many regimens that include intravenously administered 5-FU can be replaced by oral 5-FU prodrugs. Patients would benefit from development of combination 5-FU oral prodrug formulations and its associated path through the combination drug regulatory approval process.

A man in his 30s who presented with an enlarged right testicle was diagnosed with a germ cell tumor via orchiectomy. Adjuvant chemotherapy with cisplatin, etoposide and bleomycin(BEP)was initiated. He developed a headache 8 days later, followed by neurological deficits 10 days later. Magnetic resonance imaging(MRI)and magnetic resonance venography(MRV)showed thrombotic occlusion at the superior sagittal sinus. Anticoagulant therapy with heparin was initiated. However, a generalized epileptic seizure occurred 11 days later, and an antiepileptic drug therapy was initiated. The headache and neurological deficits gradually improved, and MRI findings showed that the superior sagittal sinus had re-canalized. The main cause of the sinus thrombosis in this patient was considered dehydration and cisplatin-induced hypercoagulability. Five courses of BEP therapy were carried out with care to avoid dehydration. The patient has remained free of testicular tumor recurrence, metastasis, and cerebral sinus thrombosis for 2 years. Cisplatin-based chemotherapy is an established risk factor for venous thromboembolism(VTE), and cerebral sinus thrombosis is a rare but dangerous complication. Therefore, cerebral sinus thrombosis should be considered when patients with testicular cancer who undergo cisplatin-based chemotherapy start to develop neurological symptoms. Clinicians should be aware of this treatable complication.

Purpose: Adrenocortical carcinoma (ACC) is a rare and aggressive cancer, and no current effective therapy is available for locally advanced and metastatic ACC. Drug repurposing is an emerging approach for identifying new indications for existing drugs, especially for rare cancers such as ACC. The objective of this study was to use quantitative high-throughput screening to identify agents with antineoplastic activity against ACC., Experimental Design: A screening of 4,292 compounds was performed on three ACC cell lines: BD140A, SW-13, and NCI-H295R., Results: Twenty-one active compounds were identified, with an efficacy of >80% in all three cell lines. Of these, niclosamide showed higher efficacy and lower IC50 than established anti-ACC drugs. We then validated niclosamide-inhibited cellular proliferation in all three ACC cell lines. Next, we investigated the mechanism by which niclosamide inhibited ACC cell proliferation, and found that it induced caspase-dependent apoptosis and G1 cell-cycle arrest. Niclosamide also decreased cellular migration and reduced the level of mediators of epithelial-to-mesenchymal transition, such as N-cadherin and vimentin. Furthermore, niclosamide treatment resulted in decreased expression of β-catenin. We also evaluated the effect of niclosamide on energy metabolism in ACC cell lines and found it resulted in mitochondrial uncoupling. Niclosamide treatment inhibited ACC tumor growth with no observed toxicity in mice in vivo, Conclusions: Our findings suggest that niclosamide has anti-ACC activity through its inhibition of multiple altered cellular pathways and cellular metabolism in ACC. Our results provide a preclinical rationale for evaluating niclosamide therapy in a clinical trial for ACC. Clin Cancer Res; 22(14); 3458-66. ©2016 AACR., (©2016 American Association for Cancer Research.)

EGFR is an important therapeutic target for non-small cell lung cancers (NSCLCs). Tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, are effective in cases with EGFR-activating mutations. However, most such cases become resistant through a secondary EGFR mutation, T790M. While the second-generation TKI afatinib has a higher affinity for double-mutant EGFRs, better efficacy is needed. Combining afatinib with the anti-EGFR monoclonal antibody cetuximab improves clinical outcomes, but the mechanism is unclear. Here we examined this effect using erythroleukemic K562 cells. The activating EGFR mutation L858R is sensitive to first-generation TKIs, and adding T790M confers resistance to these drugs. This double-mutant EGFR was moderately sensitive to afatinib, but responded weakly to cetuximab. Combined afatinib and cetuximab synergistically increased their cytotoxicity for K562 cells expressing the double-mutant EGFR. Apoptosis in these cells followed induction of the pro-apoptotic protein BIM. Unexpectedly, afatinib caused redistribution of EGFR to the cell surface through Rab11a-dependent recycling. Cetuximab reduced cell-surface EGFR, and total EGFR decreased synergistically when cetuximab was combined with afatinib. Our results suggest that the synergistic effect exerted by afatinib and cetuximab on NSCLCs is associated with BIM induction and alterations in EGFR status., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Pancreatic cancer is one of the life-threatening cancers due to the difficulty in the curative surgery and resistance against conventional therapeutic strategies. Recent studies indicated that cancer stem cells, which exist as a small number of cells within the entire cancer tissue, contribute to the disease progression. Cancer stem cells reveal resistance against conventional chemotherapy, which is derived from the high-expression of multiple transporter genes. Our previous study demonstrated the aggravating role of the homeobox gene MSX2 as an inducer of epithelial-mesenchymal transition, and MSX2 turned out to correlate with the chemoresistance in the current study. Comprehensive analysis of the MSX2-target gene has identified ABCG2 as the responsible gene. Since previous studies reported the pivotal role of ABCG2 as a determining factor of cancer stem cells, the detailed regulatory mechanism of ABCG2 expression by MSX2 was investigated. As a result, the MSX2 expression level in each cell line well correlated with the ABCG2 expression level, and alteration of the MSX2 expression level by over-expression or siRNA-based knockdown affected the ABCG2 expression accordingly. Finally, we identified the functional cooperation of MSX2 and SP1 in the transcriptional regulation of ABCG2 via the SP1 binding elements within the ABCG2 promoter. These findings clarified the intriguing regulatory mechanism of the cancer stem cell-related gene, and will delineate a novel therapeutic target in pancreatic cancer., (Copyright © 2011 Wiley Periodicals, Inc.)

Three Chinese herbal extracts of Drynaria baronii, Angelica sinensis and Cornus officinalis Sieb. et Zucc (referred to as DB, AS, CO, respectively) were investigated for their antitumor potential. These extracts showed very weak cytotoxicity against all nine cultured human cells (normal and tumor cells), but with some tumor-specific cytotoxicity displayed by DB and CO. These extracts showed little or no growth stimulation effects at lower concentrations (so-called 'hormetic effect'). Human oral squamous cell carcinoma cell lines (HSC-2, NA) were relatively resistant to committing apoptosis, as compared with human promyelocytic leukemia HL-60 cells. Electron-spin resonance spectroscopy shows that DB and CO scavenged superoxide anion (generated by hypoxanthine and xanthine oxidase reaction) and hydroxyl radical (generated by Fenton reaction) more efficiently than AS. DB and CO, but not AS, produced broad radical peak(s) and enhanced the superoxide scavenging activity of vitamin C. However, none of the extracts clearly enhanced the cytotoxicity of mitoxantrone, an anthracycline antitumor antibiotic. DB, but not CO and AS, showed weak anti-HIV activity. These data demonstrate several unique antitumor properties of DB.

N-beta-Alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine (5-S-GAD), an insect-derived antibacterial peptide, generates hydrogen peroxide (H(2)O(2)) that exerts antitumour activity. We have investigated the precise mechanism of H(2)O(2) production from 5-S-GAD by autoxidation aiming to understand its action toward tumour cells. Using the electron spin resonance (ESR) technique, we detected a strong signal due to radical formation from 5-S-GAD. Surprisingly, the ESR signal of the radical derived from 5-S-GAD appeared after incubation for 30 min at 37 degrees C in the buffer at pH 7.4; the signal was persistently detected for 10 h in the absence of catalytic metal ions. The computer simulation of the observed ESR spectrum together with the theoretical calculation of the spin density of the radical species indicates that an o-semiquinone radical anion was formed from 5-S-GAD. We demonstrated that H(2)O(2) is produced via the formation of superoxide anion O2(.-) by the electron-transfer reduction of molecular oxygen by the 5-S-GAD anion, which is in equilibrium with 5-S-GAD in the aqueous solution. The radical formation and the subsequent H(2)O(2) production were inhibited by superoxide dismutase (SOD), when the antitumour activity of 5-S-GAD was inhibited by SOD. Thus, the formation of the o-semiquinone radical anion would be necessary for the antitumour activity of 5-S-GAD as an intermediate in the production of cytotoxic H(2)O(2).

In search of compounds which show tumor-specific cytotoxic activity, two 3,5-dibenzoyl-1, 4-dihydropyridines (GB5, GB12) were found to show one or two orders higher cytotoxic activity against human tumor cell lines (squamous cell carcinoma HSC-2, HSC-3, submandibular gland carcinoma HSG, promyelocytic leukemia HL-60) than human normal cells (gingival fibroblast HGF, pulp cells HPC, periodontal ligament fibroblasts HPLF). GB5 and GB12 weakly induced several apoptosis-associated properties, such as internucleosomal DNA fragmentation, and activation of caspases -3, -8 and -9, in both HL-60 and HSC-2 cells. Western blot analysis showed that GB5 and GB12 transiently increased the expression of both anti-apoptotic protein (Bcl-2) and proapoptotic proteins (Bax and Bad) in HL-60 cells. ESR spectroscopy showed these compounds did not produce any detectable amount of radicals, nor scavenged superoxide (generated by hypoxanthine-xanthine oxidase reaction) or nitric oxide (generated by 1-hydroxy-2-oxo-3-(N-3-methyl-3-aminopropyl)-3-methyl-1-triazene), suggesting that the induction of cytotoxic action is not via a radical-mediated reaction. The present study suggests that GB5 and GB12 may induce non-apoptotic cell death in tumor cell lines.

The biological activities of Moxa, used as moxibustion, have not been well documented. We investigated here Moxa smoke for its tumor-specific cytotoxicity, anti-HIV activity, radical intensity and radical scavenging activity, in comparison with previously published data of Moxa extract. Moxa smoke showed slightly higher cytotoxicity against human tumor cell lines (oral squamous cell carcinoma HSC-2, HSC-3, promyelocytic leukemia HL-60) than against normal oral cells (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF), yielding a tumor specificity index of 1.29. Moxa smoke dose-dependently induced internucleosomal DNA fragmentation, activation of caspases 3, 8 and 9, and slightly modified the expression of apoptosis-related proteins (Bcl-2, Bad, Bax) in HL-60 cells, but to much lesser extents than attained by positive controls (UV irradiation, actinomycin D treatment). ESR spectroscopy showed that Moxa smoke generated semiquinone-type radicals under alkaline conditions, and scavenged O2(-), hydroxyl radical, singlet oxygen and NO. All Moxa smoke preparations showed no apparent anti-HIV activity. These data demonstrate the antitumor potential of Moxa smoke.

A total of 6 newly-synthesized styrylchromones (SC-1 approximately SC-6) were compared for their cytotoxic activity against three normal oral human cells (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF) and four human tumor cell lines (squamous cell carcinoma HSC-2, HSC-3, submandibular gland carcinoma HSG, promyelocytic leukemia HL-60). All compounds showed higher cytotoxic activity against tumor cell lines than against normal cells. Among the 6 compounds, SC-3, SC-4 and SC-5, which have one to three methoxy groups, showed higher tumor specificity and water solubility. The cytotoxic activity of SC-3 and SC-5 was slightly reduced by a lower concentration of NADH, a quinone reductase, but that of SC-3 was enhanced by higher concentrations of NADH, possibly due to demethylation of the methoxy groups. Agarose gel electrophoresis demonstrated that SC-3 and SC-5 induced intemucleosomal DNA fragmentation in HL-60 cells and production of large DNA fragment in HSC-2 cells. Both SC-3 and SC-5 enhanced the enzymatic activity to cleave the substrates for caspases 3, 8 and 9, suggesting the activation of both extrinsic and intrinsic apoptosis pathways. ESR spectroscopy showed that these compounds produced no detectable amount of radical and did not scavenge superoxide anion generated by the hypoxanthine-xanthine oxidase reaction. The highly tumor-specific cytotoxic action and apoptosis-inducing capability of SC-3 and SC-5 suggest their applicability for cancer chemotherapy.

We developed concise, accurate prediction models of the in vitro activity for 8 anticancer drugs (5-FU, CDDP, MMC, DOX, CPT-11, SN-38, TXL and TXT), along with individual clinical responses to 5-FU using expression data of 12 genes. We first performed cDNA microarray analysis and MTT assay of 19 human cancer cell lines to sort out genes which were correlative in expression levels with cytotoxicities of the 8 drugs; we selected 13 genes with proven functional significance to drug sensitivity from a huge number of potent prediction marker genes. The correlation significance of each was confirmed using expression data quantified by real-time RT-PCR, and finally 12 genes (ABCB1, ABCG2, CYP2C8, CYP3A4, DPYD, GSTP1, MGMT, NQO1, POR, TOP2A, TUBB and TYMS) were selected as more reliable predictors of drug response. Using multiple regression analysis, we fixed 8 prediction formulae which embraced the variable expressions of the 12 genes and arranged them in order, to predict the efficacy of the drugs by referring to the value of Akaike's information criterion for each sample. These formulae appeared to accurately predict the in vitro efficacy of the drugs. For the first clinical application model, we fixed prediction formulae for individual clinical response to 5-FU in the same way using 41 clinical samples obtained from 30 gastric cancer patients and found to be of predictive value in terms of survival, time to treatment failure and tumor growth. None of the 12 selected genes alone could predict such clinical responses., (Copyright 2004 Wiley-Liss, Inc.)

We are interested in the possibility of a new prostate cancer therapy that would control tumor malignancy via induction of terminal cell differentiation. We previously reported that 12-O-tetra-decanoylphorbol-13-acetate (TPA) induces differentiation into cells with characteristics of microglia and decreases the malignant characteristics of human prostatic cancer TSU-Pr1 cells. To investigate the mechanism underlying differentiation of TSU-Pr1 cells, we attempted to identify genes expressed during differentiation using differential display. We identified four genes expressed differentially after TPA treatment. Levels of expression of two genes, human flavoprotein subunit of complex II and JKTBP, were downregulated by TPA, and expression of two genes, human golgin p245 and bcl-xL, was upregulated. Moreover, we found that the changes in expression of flavo-protein, JKTBP and bcl-xL induced by TPA were blocked by treatment with protein kinase C (PKC) or mitogen-activated protein (MAP) kinase inhibitors that prevent TPA-induced differentiation of TSU-Pr1 cells. These results suggest that the differential expression of these genes is associated with TPA-induced differentiation of TSU-Pr1 cells. We expect that understanding the roles of these genes during differentiation will provide for new approaches and therapeutic targets for treatment of prostate cancer.

Ferulic acid and eugenol were examined for their superoxide (O2-), hydroxyl radical (.OH) and nitric oxide (NO)-scavenging ability, using ESR spectroscopy with spin trap agents DMPO and carboxy-PTIO/NOC-7. Ferulic acid more efficiently scavenged .OH and NO than eugenol. The O2- scavenging activity of ferulic acid was comparable with that of eugenol. Ferulic acid significantly reduced the NO production by lipopolysaccharide (LPS)-stimulated mouse macrophage-like cells (Raw 264.7 cells) compared to eugenol. The cytotoxic activity of ferulic acid against Raw 264.7 cells was comparable with that against human submandibular gland carcinoma (HSG) cells and the cytotoxicity of ferulic acid was about 10-fold smaller than that of eugenol. The stoichiometric factor (n) (number of moles of peroxy radical trapped by moles of the relevant phenol) of ferulic acid and eugenol was investigated, using the induction period methods of the methyl methacrylate polymerization system. The n-value of ferulic acid (1.5) was higher than that of eugenol (1.0) and was similar to that of 2, 6-di-t-butyl-4-methylphenol (BHT). Ferulic acid as well as eugenol may produce a dimer during the induction period due to an n-value less than 2. These results suggested that ferulic acid may be useful for preventing cell damage perhaps caused by O2-, and in particular by .OH and NO, in living systems.

Epigallocatechin gallate (EGCG) induced apoptosis-associated characteristics in human oral tumor cell lines more efficiently than ascorbates, gallic acid, vitamin K, flavonoids or steroidal saponins. Since catalase partially inhibited the cytotoxic activity of EGCG, the possible involvement of hydrogen peroxide (H2O2) in cell death induction was investigated, using TCPO chemiluminescence method. Production of H2O2 by EGCG, sodium ascorbate, gallic acid or catechin reached a maximum level within 30 minutes, and was increased up to a plateau level above pH 8. Under optimal conditions, 1 mM EGCG was converted to 1 mM H2O2. At neutral pH, EGCG produced the highest amount of H2O2, followed by gallic acid, sodium ascorbate and catechin. EGCG produced methionine sulfoxide from methionine in the culture medium, while the methionine oxidation by EGCG was significantly reduced in the presence of serum. ESR spectroscopy showed that EGCG, gallic acid and sodium ascorbate, but not catechin, produced radicals under alkaline condition and that all these compounds scavenged superoxide anion, produced by hypoxanthine-xanthine oxidase reaction. EGCG also effectively scavenged the ascorbate and gallate radicals, more efficiently than other compounds. These data suggest that the apoptosis induction by EGCG may be mediated by H2O2 produced in the culture medium.

Among 11 isoflavones tested, genistein [YS13] produced higher cytotoxic activity against human oral tumor cell lines (HSC-2, HSG) than against normal cells (human gingival fibroblast, HGF), suggesting its tumor-specific action. Electron spin resonance (ESR) spectroscopy showed that YS13 did not produce radical, nor scavenged O2*- generated by hypoxanthine-xanthine oxidase reaction system, suggesting that radical-mediated oxidation mechanism is not be involved in the YS13-induced cytotoxicity. Addition of one prenyl group produced YS18 and YS19 with higher anti-Helicobacter pylori activity. Addition of two prenyl groups produced YS21 with the highest cytotoxic activity but lower tumor-specificity. Since YS21 produced the highest amount of radical and most efficiently scavenged O2*-, this compound may induce cytotoxicity by radical-mediated oxidation mechanism. All isoflavones failed to induce anti-human immunodeficiency virus (HIV) activity. These data suggest the medicinal efficacy of isoflavones.

Cisplatin is known to activate caspase-3 through the mitogen-activated kinase (MAPK) pathway. We found that X-chromosome-linked inhibitor of apoptosis protein (XIAP), a direct inhibitor of caspase-3, 7, and 9, is constitutively expressed in a cell line of oral squamous cell carcinoma, KOSC-2. Cisplatin treatment of the cells inhibited the expression of XIAP, and this was associated with DNA fragmentation. Overexpression of XIAP, by a transfection experiment, inhibited the cisplatin-induced apoptosis. We conclude that cisplatin induces apoptosis mediated not only by the activation of MAPK pathway but by the inhibition of XIAP.

In order to elucidate the mechanisms of antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA), we established a mouse hepatocellular carcinoma model by oral administration of N-nitrosodiethylamine (NDA) and examined the ascorbate radical intensity and putrescine content in the liver. The oral intake of NDA induced precancerous lesion and a significant increase in putrescine content among three major polyamines. When the oral intake of NDA was stopped, morphological changes were reversed. ESR spectroscopy showed that the homogenate of precancerous tissues produced greater amounts of ascorbate radical than that of normal liver tissue. Intravenous administration of SBA 30 minutes before removal of the liver prolonged the higher level of ascorbate radical generation in the homogenate of precancerous tissue. The antitumor activity of SBA might be due to the long-term production of radicals in tumor tissues by its prooxidant action.

The biological activity of ten prenylflavanones purified from Sophora tomentosa L., and Sophora moorcroftiana Benth. ex Baker (Leguminosae) was investigated. The flavanones with prenyl-, lavandulyl- or geranyl groups on A ring, and two bioactive flavonostilbenes on ring B and stilbene (resveratrol) showed tumor-specific cytotoxic activity, antimicrobial activity, and anti-HIV activity, radical generation, and O2- scavenging activity. There was a positive relationship between radical generation and O2- scavenging activity in these prenylflavanones. These data suggest the medicinal significance of prenylflavanones.

The ability of nine synthetic eugenol-related compounds to scavenge O2- (generated by the hypoxanthine-xanthine oxidase reaction) was compared with their radical generation and cytotoxic activity. ESR spectroscopy showed that eugenol (4-allyl-2-methoxyphenol), 2-allyl-4-methoxyphenol, 2-allyl-4-t-butylphenol and 2,4-dimethoxyphenol efficiently scavenged O2- and produced radicals under alkaline conditions. 2-allyl-4-t-butylphenol showed the highest cytotoxic activity and DNA-synthesis inhibitory activity, possibly due to the hydrophobic radical reactivity. 2-allyl-4-methoxyphenol and 2,4-dimethoxyphenol showed higher antioxidant activity than 3-t-butyl-4-hydroxyanisol (BHA), but all these compounds showed comparable cytotoxic activity with each other. These findings suggest a possible link between the cytotoxic activity and radical generation/scavenging activity in eugenol-related compounds.

Recombinant adenovirus mediated p53 gene transfer combined with anti-cancer drugs has clinical potential for gene therapy of lung cancer. We constructed a recombinant adenoviral vector expressing wild-type p53 cDNA (Ad-p53), and assessed the efficacy of a combined treatment with Ad-p53 and six anti-cancer drugs (cisplatin, 5-fluorouracil, doxorubicin, docetaxel, irinotecan, and etoposide) for human lung cancer cell lines, H1299 (with deleted p53), RERF-LC-OK (with mutant p53), and A549 (with wild-type p53). The infection of the Ad-p53 vector into H1299 cells, RERF-LC-OK cells, or A549 cells increased the sensitivity to all six drugs regardless of the cellular p53 status, and a synergism was observed by the isobolic method in combination studies (D<1). We conclude that our strategy using adenoviral mediated p53 gene transfer to cancer cells can enhance the cytotoxic effect of anti-cancer drugs, which leading to an improvement of lung cancer chemotherapy.

To investigate the possible link between radicals and cytotoxicity of eugenol-related compounds, dimer compounds were synthesized from eugenol (4-allyl-2-methoxyphenol) or isoeugenol (4-propenyl-2-methoxyphenol): bis-eugenol (3,3'-dimethoxy-5,5'-di-2-propenyl-1,1'-biphenyl-2,2'-diol); dehydrodiisoeugenol (2-(3-methoxy-4-hydroxyphenyl)-3-methyl-5-(1-propenyl)-7-methoxy-2,3- dihydrobenzofuran) and alpha-di-isoeugenol (r-l-ethyl-5-hydroxy-t-3-(4-hydroxy-3-methoxyphenyl)-6-methoxy-c-2- methylindane). Both the cytotoxic activity and the DNA synthesis inhibitory activity of these compounds against a salivary gland tumor cell line (HSG) and normal human gingival fibroblast (HGF) were decreased in the order of: dehydrodiisoeugenol, alpha-di-isoeugenol > isoeugenol > eugenol > bis-eugenol. Electron spin resonance (ESR) spectroscopy showed that dehydrodiisoeugenol, alpha-di-isoeugenol and eugenol, but not isoeugenol and bis-eugenol, produced phenoxyl radicals under alkaline condition (pH > 9.5). However, benzyl radicals were produced during the dimerization of isoeugenol to dehydrodiisoeugenol. The radical intensity of alpha-di- and dehydrodiisoeugenol appeared at relatively later incubation time than eugenol, suggesting that their phenoxyl radical was more stable than that of eugenol. Such a phenoxyl radical is produced by scavenging free radicals, during the inhibition of lipid peroxidation. Higher cytotoxic activity of isoeugenol dimers was thought to be induced by interaction with cell membranes via the lipophilic radical. The present study supports the notion that relative cytotoxicity of chemicals can be evaluated by measuring the radical intensity using ESR.

Hydrolyzable tannins showed higher cytotoxic activity against human oral squamous cell carcinoma and salivary gland tumor cell lines than against normal human gingival fibroblasts, whereas gallic acid, a component unit of tannins, showed much weaker selective cytotoxicity. The cytotoxic activity of dimeric compounds was generally higher than that of monomeric compounds. Macrocyclic ellagitannin oligomers, such as oenothein B, woodfordin C and woodfordin D showed the greatest cytotoxic activity, and their activity (per given number of molecules) was one order higher than those of gallic acid and epigallocatechin gallate, a major component of green tea. These compounds induced apoptotic cell death characterized by DNA fragmentation (as demonstrated by the TUNEL method) and cleavage of cytokeratin 18 by activated caspase(s) (as demonstrated by M30 monoclonal antibody). ESR spectroscopy revealed that these macrocyclic compounds at higher concentrations produced their own radicals and significantly enhanced the radical intensity of sodium ascorbate, possibly by their prooxidant actions. Catalase failed to eliminate their apoptosis-inducing activity, reducing the possibility of the involvement of hydrogen peroxide production in the extracellular fraction. These observations suggested that the antitumor activity of macrocyclic ellagitannin oligomers reported previously might be explained by their apoptosis-inducing activity.

Eleven 4-phenyl-3,5-diacetyl-1,4-dihydropyridines (AcDHPs) [G1-11] substituted at the phenyl ring were synthesized and compared for their cytotoxic activity and multidrug resistance (MDR)-reversing activity in in vitro assay systems. Among them, compound [G7] showed the highest cytotoxic activity against human promyelocytic leukemia HL-60 and human squamous cell carcinoma HSC-2 cells. However, no compounds tested produced radicals at pH 7.4-12.5. The activity of P-glycoprotein (Pgp) responsible for MDR in tumor cells was reduced by compounds [G2, 3, 6, 5, 8, 1, 11], verapamil [VP] and nifedipine [NP]. However, compounds [G4, 7, 10] were hardly active while G9 did not show a MDR reversing effect at 2.0-20.0 micrograms/mL. These data show a relationship between chemical structures and MDR-reversing effect on tumor cells.

We have previously reported on the diverse biological activities of benzo[a]phenothiazines, such as the induction of antitumor and antimutagenic activity in vivo, and differentiation and apoptosis in vitro. The relationship of radical generation and pi-spin density or dipole moment was investigated, using quantum-chemical calculation with UHF/PM3. These data suggest that the origin of radical generation by active benzo[a]phenothiazines, which affect such biological activities might be N-atom at position 12.

The interaction between sodium 5,6-benzylidene-L-ascorbate (SBA) and gallic acid was investigated by two different parameters: radical intensity and cytotoxicity induction. These compounds produced ESR signals of radicals under alkaline conditions. The addition of increasing concentrations of SBA completely scavenged the gallate radical and replaced the latter with its ascorbate radical. On the other hand, gallic acid dose-dependently enhanced the radical intensity of SBA. Both of these two compounds dose-dependently reduced the viable cell number of human squamous carcinoma HSC-2 cells without inducing internucleosomal DNA cleavage. Electron micrographs of the dying cells demonstrate the irreversible degenerative changes especially in the cytoplasm of the cells. The cytotoxic activity of gallic acid was almost completely eliminated by catalase, whereas SBA was totally insensitive to catalase. When these two compounds were mixed together before adding to HSC-2 cells, the cytotoxic activity of gallic acid was significantly reduced by SBA, whereas that of SBA was not reduced by gallic acid. SBA dose-dependently reduced the gallate oxidation in the culture medium. The interaction between SBA and gallic acid may modify their individual biological activity.

We investigated whether the antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA) is mediated via oxidation-involved mechanism, in three different systems: 3'-methyl-4-dimethylaminoazobenzene (DAB)-induced rat hepatocellular carcinoma (in vivo), its homogenate (semi in vivo), and cultured cells (in vitro). Oral intake of DAB irreversibly produced hepatocellular carcinoma in rats, with a maximum incidence of carcinogenesis after 4 months. Intravenous administration of SBA induced vacuolar, eosinophilic degeneration and nuclear debris, producing greater amounts of ESR signal of ascorbate radical and hydrogen peroxide (H2O2)-derived chemiluminescence (CL) (H2O2-CL) in the cancerous tissue than in the normal tissue. When SBA was directly added to the homogenates, higher amounts of ascorbate radical and H2O2-CL were generated in cancerous tissues. When SBA was added to the RPMI1640 medium supplemented with 10% fetal bovine serum, methionine was oxidized to methionine sulfoxide and H2O2 was produced in amounts that sufficiently induce apoptotic cell death in human promyelocytic leukemic HL-60 cells. Cytotoxic activity of SBA was significantly reduced by catalase. These data suggest that antitumor activity of SBA in vivo might at least in part be due to H2O2, produced from SBA.

Six endometrial cancer cell lines (Ishikawa, EIIL, HEC1A, 6, 50 and 59), one breast cancer cell line (MCF-7) and two ovarian cancer cell lines (OVHS-1, HRA) were treated for 24 or 168 h with a gonadotropin-releasing hormone (GnRH) analogue, Buserelin acetate, and the cellular growth profile was studied. All these cell lines except for the HRA line had positive GnRH receptor mRNA expression detected by reverse transcriptase polymerase chain reaction. GnRHa suppressed cell growth after 168 h of exposure, but not after 24 h. Suppression of cell growth by the exposure to cis-platinum (CDDP, 10 nM for 24 h) was significantly increased in the presence of GnRHa for 168 h. The mechanism of this growth inhibition was tested by examining both RNA components of human telomerase (hTR) expression and telomerase activity. The results showed that GnRHa inhibits telomerase activity without altering the RNA component of telomerase expression. The present data suggest that GnRH analogue may modulate endometrial, breast and ovarian cancer cell growth through modifying the telomerase activity. Since GnRHa increased the cytotoxic effects of CDDP and GnRHa is a compound of high patient compliance, the value of GnRHa as a tumor sensitizer to CDDP should be further tested in clinical trials.

Role of hydrogen peroxide (H2O2) in the induction of cytotoxicity by ascorbic acid derivatives was investigated. Ascorbic acid derivatives which produced radicals (sodium 5,6-benzylidene-L-ascorbate (SBA), sodium-L-ascorbate, D-isoascorbic acid) dose-dependently reduced the viable cell number of human squamous carcinoma (HSC-2, HSC-4, NA), human salivary gland tumor (HSG) and human promyelocytic leukemia (HL-60) cell lines. Conversely, L-ascorbic acid-2-phosphate magnesium which did not produce radicals, was inactive. This suggests the possible role of the ascorbate radical in apoptosis induction. The cytotoxic activity of SBA was partially reduced by catalase, and the extent of inhibition by catalase was considerably different, depending upon which target cells were used. On the other hand, the cytotoxic activity of sodium ascorbate, isoascorbic acid, hydrogen peroxide and gallic acid was more effectively inhibited by catalase. These data suggest that mechanisms other than H2O2 might be involved in the induction of cytotoxicity by SBA.

The interaction between sodium 5,6-benzylidene-L-ascorbate (SBA) and dopamine was investigated by three different parameters: radical intensity, prooxidant action and cytotoxic activity. Under alkaline conditions, SBA and dopamine produced doublet and quartet ESR signals, respectively. The addition of increasing concentrations of SBA completely scavenged the dopamine radical and replaced the latter with its own radical. On the other hand, dopamine accelerated the decay of SBA radical. These two compounds stimulated the methionine oxidation in culture medium, but in combination, their stimulation activities were weakened. Both of these two compounds dose-dependently reduced the viable cell number of human promyelocytic leukemics HL-60 cells. When these two compounds were mixed together before adding to HL-60 cells, both of their cytotoxic activities were diminished. The present study demonstrates the interaction between SBA and dopamine, which might modify their biological activities.

Natural phenolic compounds, curcumin and gallic acid, were compared for their cytotoxic activity in relation to their radical modulating activity. These two compounds induced apoptotic cell death in human promyelocytic leukemic HL-60 cells and human oral squamous carcinoma HSC-4 cells. Curcumin was more cytotoxic than gallic acid. Catalase reduced significantly the cytotoxic activity of gallic acid, but not that of curcumin. ESR spectroscopy demonstrated that curcumin produced radicals under alkaline conditions, scavenged the superoxide anion radical, and enhanced the radical intensity of sodium ascorbate at higher concentrations. As compared with curcumin, gallic acid produced higher amounts of radicals and more efficiently scavenged the superoxide anion radical. Gallic acid reduced the radical intensity of sodium ascorbate, suggesting a possible interaction between these two compounds. These data suggest that curcumin and gallic acid induce apoptosis by different mechanisms.

Malignant melanoma is one of the fulminant skin cancers. The 5-year survival of patients with stage III (N0, N1) malignant melanoma treated with multi-agent chemoimmunotherapy, including natural interferon-beta (nIFNbeta), was found in our department to be better than that of patients treated with other forms of therapy. In order to study the effects of nIFNbeta on melanoma, the growth inhibition effect of nIFNbeta was assessed in vitro using the melanoma cell lines, MM8.1, MM28, MM33.1, Bowes and A375-2. The growth of these cell lines was inhibited by nIFNbeta. Incorporation of [3H]thymidine and [3H]uridine was also inhibited by nIFNbeta in a dose-dependent manner. Apoptosis was demonstrated using the TUNEL method in melanoma cell lines cocultured with nIFNbeta. Results showed that nIFNbeta had direct killer activity on melanoma cell lines.

Role of hydrogen peroxide (H2O2) in the induction of antitumor activity against chemically-induced rat hepatocellular carcinoma by sodium 5,6-benzylidene-L-ascorbate (SBA) was investigated. ESR spectroscopy demonstrated that rat liver homogenate of cancerous tissue significantly enhanced the radical intensity of SBA more potently than that of precancerous or normal tissue. The peroxyoxalate chemiluminescence method demonstrated that SBA significantly enhanced the production of H2O2-derived chemiluminescence intensity in the liver homogenates, and the effect of SBA was greater in cancerous tissue than in precancerous or normal tissue. Addition of ascorbic acid, a degradation product of SBA, showed similar but slightly weaker stimulation effects. These data suggest that antitumor activity of SBA in vivo might, at least in part, be due to H2O2 production.

The radical modulation activity of hot water and NaOH extracts of the thorn apple of Crataegus Cuneata Sieb. et. Zucc. was investigated, using ESR spectroscopy. The radical intensity of sodium ascorbate was slightly reduced at lower concentrations of the extracts, but it was synergistically enhanced at higher concentrations. Higher concentrations of the extracts also synergistically stimulated the cytotoxic action of sodium ascorbate against human oral squamous carcinoma and salivary gland tumor cell lines. All these extracts effectively scavenged superoxide anion and hydroxyl radical, produced by hypoxanthine-xanthine oxidase and Fenton reaction, respectively, and their activity was comparable with that of lignins prepared by the same procedure from other plants. These data further supports the medicinal efficacy of plant extracts.

The role of hydrogen peroxide in the induction of cell death in human promyelocytic leukemic HL-60 cells by sodium 5,6-benzylidene-L-ascorbate (SBA) and its degradation product, ascorbic acid, was investigated. Millimolar concentrations of these compounds induced cell death, characterized by cell shrinkage, nuclear and internucleosomal DNA fragmentation, disappearance of microvilli and condensation of chromatin near the nuclear membrane. Catalase significantly reduced the cytotoxic activity of these compounds, whereas superoxide dismutase, nitric oxide (NO) generator, NO scavenger and NO synthase inhibitor were inactive, suggesting the possible role of H2O2. Determination of H2O2 with the peroxyoxalate chemiluminescence demonstrated that sodium ascorbate and SBA produced H2O2 in amounts necessary for cell death induction.

Millimolar concentrations of dopamine (DA), norepinephrine (NE), and 3,4-dihydroxyphenylacetic acid (DOPAC) were cytotoxic to human promyelocytic leukemiC HL-60 cells. However, their metabolites (3,4-dihydroxymandelic acid (DOMA), 3-methoxytyramine (MT), normetanephrine (NMN)) and six synthetic derivatives (which have two OCH3 groups replacing two OH groups on catechol backbone) displayed much lower cytotoxic activity. Three active compounds, but not other less potent compounds, produced radicals under alkaline conditions. All active compounds significantly enhanced the decay of ascorbic acid endogenously present in rat brain homogenate, whereas all synthetic derivatives were inactive. Ascorbic acid induced apoptotic cell death in HL-60 cells and the apoptosis induction was significantly reduced by simultaneous addition of (DA). The cytotoxic activity of (DA) was also neutralized by ascorbic acid. These data suggest the possible interaction between (DA) and ascorbic acid.

Ten 6,12-dihydro-1-benzopyrano[3,4-b][1,4]benzothiazin-6-ones (Coumarins)[1-7] and related coumarins [8-10] were compared for their cytotoxic activity and radical intensity. Among these compounds, compound 7 showed highest cytotoxic activity against human promyelocytic leukemic HL-60 cells. Compound 7 produced radicals under alkaline conditions, and showed the lowest pi-spin density at S-atom of the molecule, suggesting the delocalization of pi-spin density. These data suggest the possible relation between radical intensity and biological activity.

The structure and activity relationship of fifteen "half-mustard type" phenothiazines and related compounds were investigated. These compounds did not show any direct bactericidal activity, possibly due to the lack of radical generation activity. Pretreatment with phenothiazines significantly reduced the lethality of Escherichia coli GN2411 infection, possibly due to activation of the host defense mechanism. Higher concentrations of these compounds showed cytotoxic activity against several cultured tumor cell lines. However, no clear-cut relationship was established between biological activity and two dipole moments (mu g, mu e).

The purpose of this study was to investigate the correlation between histopathological changes and 201Tl accumulation in tumor following chemotherapy in the evaluation of chemotherapeutic effect. Walker 256 carcinoma implanted in the right thighs of Wistar rats was treated by the intravenous injection of adriamycin (ADR). 201Tl scintigraphy was performed before and 12, 24, 72, and 96 hours after chemotherapy. The count ratio of tumor to normal muscle (T/N ratio) was measured by gamma camera. Tumor growth rate was measured and histopathological examination of the tumor after 201Tl scintigraphy was performed. The tumors of all rats disappeared within 2 weeks after chemotherapy, but the T/N ratio did not change. Histopathological findings showed a decrement of tumor cells, small necrotic regions, and remarkable lymphocyte infiltration in the tumor bed in the healing stage. After 201Tl injection, lymphocytes isolated from tumor tissue showed noted 201Tl accumulation. These results suggest that the T/N ratio did not decrease after ADR chemotherapy because of the accumulation of 201Tl in lymphocytes. We concluded that the use of 201Tl may underestimate the therapeutic effect of ADR.

This review summarizes our comparative study of the antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA) and sodium ascorbate. Both SBA and ascorbate produced ascorbate radicals during decomposition, elevated oxidation potential and oxidized methionine to methionine sulfoxide, in the regular culture medium. They induced apoptotic cell death (characterized by internucleosomal DNA fragmentation) in human myelogenous leukemic cell lines, but killed most of other tumor cell lines by necrosis without induction of internucleosomal DNA fragmentation. The cytotoxic activity of SBA and ascorbate was significantly enhanced in the presence of copper and the stimulation effect of copper was reduced by a heavy metal antagonist. However, the cytotoxic activity of SBA was only slightly modified by iron, cysteine analog or catalase, in contrast to ascorbate, which was highly sensitive to all these agents. Furthermore, intravenous administration of SBA induced degeneration in chemically-induced hepatocellular carcinoma whereas ascorbate was inactive. These data suggest the differential mode of antitumor action between these two compounds.

The effect of various physiological fluids on the radical intensity of sodium ascorbate and sodium 5,6-benzylidene-L-ascorbate (SBA) was investigated using ESR spectroscopy. Blood from various animals did not significantly affect the radical intensity of both ascorbates, whereas the corresponding plasma fractions significantly enhanced the radical intensity. This suggests that some populations of blood cells might modify the interaction between plasma components and ascorbates. Saliva contained labile substance(s) which effectively reduced the ascorbate radical intensity. HPLC demonstrated the presence of endogenous ascorbate in rat liver and brain homogenates. When sodium ascorbate or SBA was incubated with any of these homogenates, their radical intensity was synergistically enhanced, but abruptly declined without any apparent ascorbate degradation. Incubation with homogenates elevated the radical intensity of SBA up to the level significantly higher than that of sodium ascorbate. The present data suggest that antitumor action of SBA might be mediated via the accelerated production of ascorbate radical in the target organ.

Relationship between the biological activity and two different dipole moments were investigated in 9 benzo[a]phenothiazines [1-8] by calculating the dipole moment with the PM3 method. 12H-Benzo[a]phenothiazine [1], 9-methyl-12H-benzo[a]phenothiazine [2], 10-methyl-12H-benzo[a]phenothiazine[3] and 11-methyl-12H-benzo[a]phenothiazine [4] induced monocytic differentiation of human myelogenous leukemic cell lines and displayed antitumor activity. These active compounds showed a significantly smaller value of calculated ground-state dipole moment (mu g) and larger value of first excited-state dipole moment (mu e). The mu e/mu g ratio of four active compounds [1-4] ranged from 3.25 to 4.38, whereas that of three inactive compounds [5,6,7] ranged from 1.77 to 2.72. These two different dipole moments might be useful parameters for estimation of the biological activity of benzo[a]phenothiazines [1-8].

The modifying effect of dietary administration of a xanthine oxidase inhibitor 1'-acetoxychavicol acetate (ACA) present in an edible plant Languas galanga in Thailand on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) was investigated in rats. Male F344 rats were given s.c. injections of AOM (15 mg/kg body wt) once a week for 3 weeks to induce colonic ACF. They were fed the diets containing 100 or 200 ppm ACA for 5 weeks, starting 1 week before the first dosing of AOM. At the termination of the study (week 5), AOM induced 118 +/- 28 ACF/colon. Dietary administration of ACA caused significant reduction in the frequency of ACF (41% inhibition by 100 ppm ACA feeding and 37% inhibition by 200 ppm ACA feeding, P<0.01). Such inhibition might be associated with suppression of the proliferation biomarkers' expression such as ornithine decarboxylase activity in the colonic mucosa, number of silver-stained nucleolar organizer regions' protein in the colonic mucosal cell nuclei and blood polyamine content. These results indicate that ACA could inhibit the development of AOM-induced ACF through its suppression of cell proliferation in the colonic mucosa and ACA might be a possible chemopreventive agent against colon tumourigenesis.

Four antioxidants, sodium ascorbate, gallic acid, n-propyl gallate and caffeic acid, induced apoptotic cell death in human promyelocytic leukemic HL-60 cells. The effects of all these compounds were enhanced by CuCl2 or deferoxamine mesylate, an iron chelator, but were reduced by FeCl3. ESR spectroscopy showed that both CuCl2 and FeCl3 enhanced the ascorbyl radical intensity, but reduced the gallate and caffeate radical intensity. The present data demonstrate that copper and iron ions modify the cytotoxic activity of these antioxidants differently and their radical intensity is not the sole determinant of cytotoxic activity.