(2″-R)-4′-o-Tetrahydropyranyladriamycin,a new anthracycline derivative; its effectiveness in lymphoid malignancies

Summary Thirty-eight patients with adult acute lymphoblastic leukemia (ALL) or non-Hodgkin's lymphoma (NHL) were treated intravenously with (2-R)-4-o-Tetrahydropyranyladriamycin (THP) at a dose of 10 mg/m² for 5 consecutive days. Seven complete and 15 partial responses were observed in 35 evaluable patients (overall response rate, 62.8%). Both antitumor activity and antitumor spectrum were similar to those for doxorubicin. Since the patients who had had chemotherapy previously, including other kinds of anthracycline, responded rather poorly to THP, cross-resistance between THP and other anthracyclines may be present. Leukopenia and thrombocytopenia were dose-limiting factors. Nausea and vomiting episodes were mild, and epilation was also minimal. Although the observation period was short and a cumulative dose was not large enough to evaluate cardiotoxicity, there were no abnormal EKG changes or clinical signs of cardiotoxicity in this study. THP is a potent antitumor agent in the treatment of lymphoid malignancies.     

Antitumor activity and cytotoxicity of a new ankinomycin derivative, 3′-, 11-dibutyryl ankinomycin

Ankinomycin is a new antitumor antibiotic found in the culture broth ofStreptomyces sp. SF2587. Ankinomycin showed marked cytotoxicity and antitumor activity against some murine leukemias, but the activity against murine solid tumors was rather weak because of its strong acute toxicity. We synthesized ankinomycin acyl derivatives and examined their antitumor activity. Among the derivatives, 3, 11-dibutyryl ankinomycin (AN1006) exhibited the highest antitumor activity. The antitumor activity of AN1006 was dependent on the administration schedule, and on the most effective schedule, AN1006 showed activity comparable with that of Adriamycin (ADM) against murine solid tumors and leukemias. AN1006 showed a cytotoxic spectrum different from that of ADM, exhibiting cytotoxicity stronger than that of ADM against colon carcinoma, stomach carcinoma, and some leukemia cell lines. According to these in vitro effects, AN1006 showed antitumor activity superior to and equal to that of ADM against human colon xenografts and stomach carcinoma xenografts in athymic nude mice, respectively. AN1006 was effective against multidrugresistant tumors in vitro and in vivo. AN1006 is an interesting candidate for further evaluation.Abbreviations ANK ankinomycin - AN1006 3-, 11-dibutyryl ankinomycin - ADM Adriamycin - ILS increase in life span - ILS_max the maximal value of increase in life span - IC₅₀ concentration required for 50% inhibition of cell growth - P388/ADM Adriamycin-resistant P388 cells - LLC Lewis lung carcinoma - CEM/VLB₁₀₀ vinblastine-resistant CCRF-CEM cells - 2780AD Adriamycin-resistant A2780 cells - KBC-4 colchicine-resistant KB3-1 cells - K562/ADM Adriamycin-resistant K562 cells - MCF-7/ADM Adriamycin-resistant MCF-7 cells This research was supported by grants from the Ministry of Education, Science and Culture and the Ministry of Health and Welfare, Japan     

Antitumor mechanisms and metabolism of the novel antitumor nucleoside analogues, 1-(3-C-ethynyl-β-D-ribo-pentofuranosyl)cytosine and 1-(3-C-ethynyl-β-D-ribo-pentofuranosyl)uracil

The antitumor ribonucleoside analogues 1-(3-C-ethynyl-β-d-ribo-pentofuranosyl)cytosine (ECyd) and 1-(3-C-ethynyl-β-d-ribo-pentofuranosyl)uracil (EUrd), first synthesized in 1995, have strong antitumor activity against human cancer xenografts without severe side effects. Here, we studied the antitumor mechanisms of ECyd and EUrd using mouse mammary tumor FM3A cells in vitro and the mechanism of selective cytotoxicity of ECyd using human tumor xenografts in nude rats in vivo. In FM3A cells, ECyd and EUrd were rapidly phosphorylated to ECyd 5′-triphosphate (ECTP) and EUrd 5′-triphosphate (EUTP), which strongly inhibiting RNA synthesis. Cells treated with EUrd were later found to contain both EUTP and ECTP, and ECTP accumulated as the final product. Probably the uracil moieties of EUrd derivatives were efficiently converted to cytosine moieties in the cells. EUrd and its derivatives were minor metabolites in the cells treated with ECyd, so cytidine forms probably were not converted to uridine forms at the nucleoside or nucleotide stage. The ultimate metabolite of ECyd and EUrd, ECTP, is stable in cultured cells with a half-life of at least 3 days, so ECyd and EUrd are on a “closed” metabolic pathway to ECTP. These characteristics of ECyd and EUrd may be important for their antitumor activity. ECyd had strong and selective antitumor activity against the human tumor xenografts. ECyd-phosphorylating activity (uridine/cytidine kinase) in the xenografts was higher than that in the organs of the rats. This finding may account for the strong activity with mild side effects. ECyd and EUrd may be a new kind of antitumor nucleoside analogue for clinical use. Received: 8 June 1998 / Accepted: 5 November 1998     

Possible factors in the potentiation of 1-(2-chloroethy)-3-trans-4-methylcyclohexyl-1-nitrosourea cytotoxicity by α-difluoromethylornithine in 9L rat brain tumor cells

Depletion of intracellular levels of polyamines in 9L rat brain tumor cells by α -difluoromethylornithine (DFMO), an enzyme-activated irreversible inhibitor of ornithine decarboxylase, significantly enhanced the cytotoxicity of 1-(2-chloroethyl)-3-trans-4-methylcyclohexyl-1-nitrosourea (MeCCNU) in vitro as measured by a colony-forming efficiency assay. Administered as a single agent, DFMO was not cytotoxic to 9L cells. Treatment for 48 hr with 10, 1, 0.5 or 0.1 mM DFMO produced similar levels of polyamine depletion and similar potentiation of MeCCNU cytotoxicity. Restoration of intracellular polyamine levels by the addition of exogenous putrescine (1 mM) to treated cells prevented the potentiation of MeCCNU, which indicates that this phenomenon might be the result of polyamine depletion. DNA adduct formation in polyamine-depleted and control cell was studied with [14C]-MeCCNU; no difference in monoadduct formation was found between polyamine-depleted and control cells. Experiments to determine whether polyamine depletion has an effect on enzymes involved in the repair of alkylated bases showed that the activity of O⁶-methylguanine-DNA demethylase, 7-methylguanine-DNA glycosylase and 3-methyladenine-DNA glycosylace were unaffected by 48 hr of treatment with 10 mM DFMO. DFMO treatment causes a substantial increase in the intracellular content of decarboxylated S-adenosyl-l-methionine, which was reversed by addition of putrescine. The possibility that the elevation of decarboxylated S-adenosyl-l-methionine rather than the depletion of polyamines is responsible for the effects of DFMO is discussed.     

A pharmacokinetic study on Z-(±)-2-(1-benzylindole-3-yl-methylene)azabicyclo[2.2.2]octane-3-ol; a novel radio-sensitization agent

Purpose The purpose of this research was to characterize the pharmacokinetic parameters and to evaluate the absolute bioavailability of the targeted compound: Z-(±)-2-(1-benzylindole-3-yl-methylene)azabicyclo[2.2.2]octane-3-ol (BMABO), a novel radio-sensitization agent, after oral delivery. Methods Sprague–Dawley rats received a single oral dose of 20 mg/kg and this was compared with intravenous administration of the compound (1 mg/kg). Blood samples were collected at different time points, and plasma BMABO concentrations were determined using a new sensitive and specific LC/MS analytical method, which utilized electrospray ionization. Results The bioavailability of orally administered BMABO was determined by comparing plasma concentrations after oral gavage delivery with intravenous delivery. Following delivery of the oral dose, the average C _max was 1,710 ± 503 ng/ml, and the AUC-value was found to be 3,561 ± 670 ng min kg/ml mg. Relative to the intravenous dose (100% bioavailability), the bioavailability was 6.2% after oral administration. Conclusion As the current studies demonstrate the novel radio-sensitization agent BMABO may have potential therapeutic valuable in cancer treatment. Further evaluation of the efficacy and toxicity of BMABO will determine the feasibility of the oral route for future clinical studies.     

Histone demethylase RBP2 promotes malignant progression of gastric cancer through TGF-β1-(p-Smad3)-RBP2-E-cadherin-Smad3 feedback circuit

Some feedback pathways are critical in the process of tumor development or malignant progression. However the mechanisms through which these pathways are epigenetically regulated have not been fully elucidated. Here, we demonstrated that the histone demethylase RBP2 was crucial for TGF-β1-(p-Smad3)-RBP2-E-cadherin-Smad3 feedback circuit that was implicated in malignant progression of tumors and its knockdown significantly inhibited gastric cancer (GC) metastasis both in vitro and in vivo. Mechanistically, RBP2 can directly bind to E-cadherin promoter and suppress its expression, facilitating EMT and distant metastasis of GC. RBP2 can also be induced by TGF-β1, a key inducer of EMT, through phosphorylated Smad3 (p-Smad3) pathway in GC. The upregulated RBP2 can be recruited by p-smad3 to E-cadherin promoter and enhance its suppression, contributing to the promotion of metastasis of GC. In addition, the suppression of E-cadherin by RBP2 attenuated inhibition of Smad3 phosphorylation (exerted by E-cadherin), resulting further induction of RBP2 expression, and thus constituting positive feedback regulation during GC malignant progression. This TGF-β1-(p-Smad3)-RBP2- E-cadherin-Smad3 feedback circuit may be a novel mechanism for GC malignant progression and suppression of RBP2 expression may serve as a new strategy for the prevention of tumor distant metastasis.     

The Effect of (E)-1-(4’-aminophenyl)-3-phenylprop-2-en-1-one on MicroRNA-18a,Dicer1, and MMP-9 Expressions against DMBA-Induced Breast Cancer

Background: Most of breast cancer patients are estrogen receptor alpha-positive and have high resistance and side effect of chemotherapeutic drug. Therefore, discovering an effective anticancer agent is needed. This research explored the effect of (E)-1-(4’-aminophenyl)-3-phenylprop-2-en-1-one (APE) on miR-18a, Dicer1, and MMP-9 expressions. Methods: Twenty four female Sprague-Dawley rats were invetigated in this study. The rats were divided into 6 groups of 4. G1 was considered as normal rat. G2, G3, T1, T2, and T3 were given DMBA 20 mg/kgBW twice a week for 5 weeks to induce mammary cancer. After being affiliated with cancer, G2 was given vehicle and G3 was treated with tamoxifen. T1, T2, and T3 were treated with APE intraperitoneally everyday for 21 days at doses of 5, 15, and 45 mg/kgBW/day, respectively. Blood plasma was collected to measure miR-18a expression using qRT-PCR. Mammary tissues were also collected to determine Dicer1 and MMP-9 expressions by using  immunohistochemistry. Results: The results showed significant down-regulation of miR-18a relative expression and up-regulation of Dicer1 expression in G3 and T1 compared to G2 (P<0.05). MMP-9 expression has significant decrease in T1 compared to G2 (P<0.05). Conclusion: APE can decrease miR-18a and MMP-9 expressions and increase Dicer1 expression in rat mammary cancer. Therefore, this compound could be a candidate of novel anticancer.     

Role of RNase L in apoptosis induced by 1-(3-C-ethynyl-β-d-ribo-pentofuranosyl)cytosine

Purpose  1-(3-C-Ethynyl-β-d-ribo-pentofuranosyl)cytosine (ECyd), a ribonucleoside analog, has a potent cytotoxic activity against cancer cells. The present studies have been performed to elucidate the overall mechanisms of ECyd-induced apoptotic cell death. Methods  Cultured cells of mouse mammary carcinoma FM3A and human fibrosarcoma HT 1080 lines were used. The efficacy of RNA synthesis inhibition by ECyd was assessed by kinetic analysis using nuclei isolated from FM3A cells. RNA status in ECyd-treated cells was investigated by Northern blots, and the cleavage sites of RNA were identified by rapid amplification of 5′ cDNA ends (5′-RACE). The effect of protein functions on the ECyd-induced apoptotic pathway was analyzed by siRNA and immunohistochemical techniques. Apoptotic cells were detected by TdT-mediated dUTP-biotin Nick End Labeling (TUNEL) assay. Results  ECyd induces inhibition of RNA synthesis in vitro and in vivo, which appears to be a major cause for the apoptosis. It is known that ECyd is converted inside the cell into its 5′-triphosphate (ECTP). We have now found in test-tube experiments that ECTP strongly inhibits the activity of RNA polymerase I by competing with CTP. In the absence of robust RNA synthesis, the cellular RNAs would be destined to break down. RNase L was found to be playing a role in the breakdown: thus, the 28S rRNA-fragmentation pattern observed for the ECyd-treated cells was very similar to that observable in an in vitro treatment of the 28S ribosomes with RNase L. Association of RNase L with the cytotoxic action of ECyd was confirmed by use of the siRNA-mediated suppression of the cellular RNase L. Thus, the cells in which the RNase L was knocked-down were highly resistant to the cytotoxic action of ECyd. Further events, downstream of the RNase L action that can lead to the eventual apoptosis, would conceivably involve the phosphorylation of c-jun N-terminal kinase and subsequent decrease in mitochondrial membrane-potential. Evidence to support this flow of events was obtained by siRNA-experiments. Conclusion  The results from this study demonstrated that RNase L is activated after the inhibition of RNA polymerase, and induces mitochondria-dependent apoptotic pathway. We propose this new role for RNase L in the apoptotic mechanism. These findings may open up the possibility of finding new targets for anticancer agents. Tomoharu Naito and Tatsushi Yokogawa have contributed equally to the main findings of the paper.     

O~6-METHYLGUANINE-DNA METHYLTRANSFERASE ACTIVITY AND SENSITIVITY OF 20 CHINESE TUMOR CELL STRAINS TO 1-(4-AMINO-2-METHYL-5-PYRIMIDINYL) METHYL-3-(2-CHLOROETHYL)-3-NITROSOUREA

O6-methylguanine-DNA methyltransferase (MGMT) plays an important role in repairing alkylated DNA. MGMT activity as well as cellular sensitivity to 1- ( 4- amino- 2-methyl-5-pyrimidinyl) methyl-3- ( 2-chloroethyl)-3-nitrosourea (ACNU) of 20 Chinese tumor cell strains were assayed. A linear response between MGMT activity and ACNU sensitivity (D10) was observed. The lower the MGMT activity In the cells, the more the sensitivity to ACNU killing. It suggested that assay of MGMT activity in tumor biopsy could be used as a guide to predict the effectiveness of ACNU treatment in chemotherapy of human cancer.     

Pharmacokinetics and antitumor activity of a new platinum compound,cis-malonato[(4R,5R )-4,5-bis(aminomethyl)-2-isopropyl- 1, 3-dioxolane]platinum(II), as determined by ex vivo pharmacodynamics

The pharmacokinetics and ex vivo pharmacodynamics studies oncis-malonato[(4R,5R)-4,5-bis (aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) (SKI 2053R, NSC D644591), cisplatin (CDDP), and carboplatin (CBDCA) were performed in beagle dogs. Equitoxic doses of SKI 2053R, CDDP, and CBDCA (7.5, 2.5, and 15.0 mg/kg, respectively) were given by i.v. bolus to three beagle dogs in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the three drugs declined in a biexponential fashion. The mean area under the concentration-time curve (AUC₀) determined for ultrafiltrable platinum derived from SKI 2053R, as an active component, was 7.72±2.74 g h ml^–1 (mean ± SD), with an initial half-life of 0.37±0.20 h, a terminal half-life of 2.19±0.93 h, a total clearance of 16.83±4.76 ml min^–1 kg^–1, and a steady-state volume of distribution of 1.57±0.30 l/kg. The ex vivo antitumor activity of SKI 2053R was assessed using the ultrafiltrable plasma against two human lung-adenocarcinoma cell lines (PC-9 and PC-14) and five stomach-adenocarcinoma cell lines (MKN-45, KATO III, SNU-1, SNU-5, and SNU-16) by tetrazolium-dye (MTT) assay and was compared with that of CDDP and CBDCA using an antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value was shown to be ranked in the following order: SKI 2053R > CBDCA > CDDP. The mean ATI values recorded for SKI 2053R and CBDCA were significantly (P<0.05) higher than that noted for CDDP; however, no statistically significant difference was observed between SKI 2053R and CBDCA, suggesting that the antitumor activity of SKI 2053R is superior to that of CDDP and is equivalent to that of CBDCA. These results suggest that SKI 2053R is a promising candidate for further development as a clinically useful anticancer drug.     

Association of tissue promoter methylation levels of APC, TGFβ2, HOXD3 and RASSF1A with prostate cancer progression

Aberrant promoter methylation is known to silence tumor-suppressor genes in prostate cancer (PCa). We correlated quantitative promoter methylation levels of APC, TGFβ2 and RASSF1A in 219 radical prostatectomies diagnosed between 1998 and 2001 with clinicopathological follow-up data available including Gleason Pattern (GP), Gleason Score (GS) and pathological stage and explored their potential in predicting biochemical recurrence using univariate and multivariate analyses. We observed that the average methylation levels of APC increased significantly from GS ≤ 6 to GS7, and pT2 to pT3a, and that of TGFβ2 increased from GS ≤ 6 to GS7, but not for RASSF1A. PCa samples were also stratified into high methylation (HM) and low methylation (LM) groups based on the PMR scores of all cases analyzed for each marker. The HM frequency of APC was greater in pT3a than pT2, and in GS ≥ 8 than GS ≤ 6. The HM frequency also increased significantly from GP3 to GP4 for APC, TGFβ2 and RASSF1A. APC methylation level was a significant predictor of biochemical recurrence in univariate analysis (p-value = 0.028). Finally, we combined methylation data of these three genes with the previously reported novel methylation biomarker HOXD3. Quantitative methylation assessment of a multiplex panel of markers, consisting of APC, HOXD3 and TGFβ2, outperforms any single marker for the prediction of biochemical recurrence (p-value = 0.017). Our study demonstrated that quantitative increase in promoter methylation levels of APC, HOXD3 and TGFβ2 are associated with PCa progression.     

DEPLETION OF O~6-METHYLGUANINE-DNA METHYLTRANSFERASE ACTIVITY AND POTENTIATION OF 1-(4-AMINO-2-METHYL-5- PYRIMIDINYL) METHYL-3 (2-CHLOROETHYL)-3-NITRO- SOUREA ANTITUMOR EFFECT BY STREPTOZOTOCIN

O6-methylguanine-DNA Methyltransferase (MGMT) can specifically repair the DNA demage Induced by chioroethylnitrosoureas (CENU) such at 1-(4-amino-2-methyt-pyrlmidinyl) methyl-3-(2-chloroethyl-)-3-nitrosourea (ACNU), constituting the molecular basis of tumor cell resistance to CENU. The present study demonstrated that sensitization of resistant tumor cells to ACNU could be achieved by streptozotocin (STZ) treatment which could deplete MGMT activity in vitro and in vivo. It suggested that depletion of the molecular basis of tumor cell resistance to chemotherapeutic agents might be a practicable way to improve the effectiveness of tumor chemotherapy.     

2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖对人食管癌细胞Eca-109的致凋亡研究

目的探讨2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖是否具有诱导人食管癌细胞Eca-109发生凋亡的作用.方法采用体外细胞培养实验方法,应用MTT法、流式细胞仪检测、DNA琼脂糖凝胶电泳、透射电镜等技术,观察药物对细胞生长的抑制率及细胞的形态学变化,检测凋亡峰及DNA Ladder.结果 MTT法测得细胞抑制率具有显著的时间及浓度依赖性;透射电镜下可见到凋亡典型的形态学变化,流式细胞仪检测显示细胞周期的G1期阻滞及凋亡峰;DNA琼脂糖凝胶电泳显示清晰的DNA梯状电泳.结论 2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖能够明显的抑制人食管癌细胞Eca-109的增殖,并诱导其发生凋亡.