Potent in vivo antineoplastic activity of MCR peptides MCR-4 and MCR-14 against chemotherapy-resistant human small cell lung cancer

Previous studies have shown that MCR peptides possessing the retinoblastoma protein (RB) fragment LFYKKV as the active site are able to inhibit the proliferation of human non-small cell lung cancer (NSCLC) cells in vitro and in vivo. The goal of the present study was to test these compounds against human small cell lung cancer (SCLC) in vivo since this tumor is notoriously resistant to conventional therapy or, respectively, is characterized by rapid relapse after initially successful treatment. We herein report that the MCR peptides MCR-4 and MCR-14 display potent antiproliferative activity against RB-negative H82 SCLC xenograft tumors in nude mice, whereas the chemotherapeutic agent VP-16 tested in parallel in a clinically relevant dose had no anti-tumor effect. These encouraging results warrant accelerating the introduction of MCR peptides into clinical trials in patients with RB-negative tumors such as SCLC in the near future.     

New natural products in cancer chemotherapy

Four new and clinically relevant antineoplastic natural products are reviewed. Taxol is derived from the bark of the western yew. It promotes the formation of microtubule bundles which deform the cytoskeleton and interfere with mitosis. Although phase II efficacy testing is incomplete, taxol is effective in the treatment of patients with ovarian carcinoma and has some activity in patients with non-small cell lung cancer and melanoma. It remains untested against several other neoplasms. The chief toxicities of taxol are myelosuppression, mucositis, anaphylactoid reactions, and peripheral neuropathy. Homoharringtonine is the most active and abundant of the cephalotaxine esters derived from the genus Cephalotaxus. This agent appears to act at the ribosome to inhibit protein synthesis and has clinical activity in patients with acute myelogenous leukemia. The dose limiting toxicities of homoharringtonine are hypotension and myelosuppression. SKF 104864 and CPT-11 are derivatives of camptothecin which are still in early clinical trials. They are cytotoxic in vitro, acting through an interaction with topoisomerase I to induce DNA fragmentation. The spectra of activity and toxicity of SKF 104864 and CPT-11 are still undefined. All four of these new natural products offer possibilities for clinical activity for patients with a variety of malignancies.     

New alpha-amino phosphonic acid derivatives of vinblastine: chemistry and antitumor activity

A series of new amino phosphonic acid derivatives of vinblastine (1, VLB) has been synthesized and tested in vitro and in vivo for antitumor activity. The compounds were obtained from O4-deacetyl-VLB azide. All of the new products studied were capable of inhibiting tubulin polymerization in vitro. The most potent antitumor compounds bore an alkyl substituent on the phosphonate. In these compounds, the anti-tumor activity strongly depended on the stereochemistry of the phosphonate. The phosphonate (1S)-[1-[( O4-deacetyl-3-de(methoxycarbonyl)vincaleukoblastin-3-yl] carbonyl]amino]-2-methylpropyl]phosphonic acid diethyl ester exhibited a remarkable activity against cancer cell lines both in vitro and in vivo.     

Design and optimization of 20-O-linked camptothecin glycoconjugates as anticancer agents.

To improve the biological profile of 20(S)-camptothecin, a novel class of 20-O-linked camptothecin glycoconjugates has been designed for preferential cellular uptake into tumor cells by an active transport mechanism. Such conjugates have been optimized for enhanced solubility, stabilization of the camptothecin lactone ring, sufficient hydrolytic and proteolytic stability, and for an overall improvement in tumor selectivity. The constitution of the peptide spacer has a major impact on stability and biological activity of the conjugates both in vitro and in vivo. Glycoconjugates 17-22 with valine residues at the linkage position to camptothecin are sufficiently stable and show good antitumor activity in vitro against HT29 and other tumor cell lines. Fluorescence microscopy and flow cytometry experiments indicate that glycoconjugates such as 19 are taken up into lysosomal compartments of the tumor cell line HT29 by an active transport mechanism. The steric configuration of the particular amino acid residues linked to the camptothecin moiety has a major impact on the in vivo activity of the corresponding glycoconjugates in the breast cancer xenograft MX-1 model. Inhibiting tumor growth by >96%, the glycoconjugates 19 and 21 show the best activity in this particular model and have been investigated more extensively. The glycoconjugate 19 compares favorably to topotecan 4 and glycoconjugate 21 with respect to toxicity against hematopoietic stem cells and hepatocytes. Based on its profile, 19 has been selected for clinical trials.     

Preclinical study of the cyclodextrin-polymer conjugate of camptothecin CRLX101 for the treatment of gastric cancer

Camptothecin showed remarkable anticancer activity in animal models of cancer but was restricted in clinical use for its adverse toxicity in patients. The preclinical efficacy of CRLX101, a nanoparticle (NP) assembly containing cyclodextrin-based polymer and camptothecin was evaluated by in vitro cytotoxicity in gastric cancer cell lines and in vivo antitumor effects in human gastric cancer cell line BGC823 xenografts. Treated tumor sections were analyzed for presence of NPs and compared with vehicle control tumors for hypoxia and angiogenesis. Gastric cancer cell lines showed high in vitro cytotoxicity for CRLX101 and also showed strong antitumor activity in vivo. Electron micrographs revealed the intracellular presence of NPs in close proximity to vesicles. A significant decrease in expressions of carbonic anhydrase, VEGF, and CD31 proteins in treated tumors indicated an inhibition of hypoxia and angiogenesis. The results provide preclinical data for gastric adenocarcinoma. FROM THE CLINICAL EDITOR: This study describes a nanoparticle assembly containing cyclodextrin-based polymer and camptothecin, resulting in increased bioavailability of camptothecin, an effective but toxic anti-cancer agent. The antitumor effects and safety profile were demonstrated in a gastric carcinoma cell line.     

Antitumor agents 288: design, synthesis, SAR, and biological studies of novel heteroatom-incorporated antofine and cryptopleurine analogues as potent and selective antitumor agents

Novel heteroatom-incorporated antofine and cryptopleurine analogues were designed, synthesized, and tested against a panel of five cancer cell lines. Two new S-13-oxo analogues (11 and 16) exhibited potent cell growth inhibition in vitro (GI(50): 9 nM and 20 nM). Interestingly, both compounds displayed improved selectivity among different cancer cell lines, in contrast to the natural products antofine and cryptopleurine. Mechanism of action (MOA) studies suggested that R-antofine promotes dysregulation of DNA replication during early S phase, while no similar effects were observed for 11 and 15 on corresponding replication initiation complexes. Compound 11 also showed greatly reduced cytotoxicity against normal cells and moderate antitumor activity against HT-29 human colorectal adenocarcinoma xenograft in mice without overt toxicity.     

Cytotoxicity of lissoclibadins and lissoclinotoxins, isolated from a tropical ascidian Lissoclinum cf. badium, against human solid-tumor-derived cell lines

The in vitro growth inhibitory activity of lissoclibadins and lissoclinotoxins isolated from the tropical ascidian Lissoclinum cf. badium against nine human cancer cell lines was examined to evaluate their potential anticancer efficacy. Lissoclibadins 1 (1) and 2 (2), and lissoclinotoxin F (4) showed the strongest activity of the six compounds tested, which were more potent than the anticancer drug cisplatin. Compound 1 has a trimeric structure, and compounds 2 and 4 are structural isomers possessing dimeric structures connected by disulfide and sulfide bonds of trans- and cis-orientations, respectively. Lissoclibadin 3 (3), a dimeric compound connected by two sulfide bonds, and two monomeric compounds (5, 6) were less active than 1, 2, and 4. Lissoclibadin 2 (2) was the most interesting compound possessing potent inhibitory activity against colon (DLD-1 and HCT116), breast (MDA-MB-231), renal (ACHN), and non-small-cell lung (NCI-H460) cancer cell lines and showing no toxicity following a 50 mg/kg single treatment to mice, and preferable stability in rat plasma.     

喜树碱多相脂质体(PL-CSA)的研究

制成了喜树碱多相脂质体(PL—CSA)。动物实验显示,PL—CSA对ECA,ECS带瘤小鼠有抗癌作用,急性毒性为喜树碱的5～7/10,LD₅₀=130mg/kg。ECS带瘤小鼠单次静注后,喜树碱在体内的分布以胆(含胆汁)为最高,依次是肠(含内容物)、胃(含内容物)、肾、脾、心、肺、肝、骨髓、瘤和血。本文首次应用离心沉降法测定PL—CSA灭菌前后的粒径大小及其分布,D_a=1.3～1.4μm,D_v=1.7μm。联用超滤和超离心技术测定PL—CSA中喜树碱的包封率、吸附率和游离量,分别为32.4～47.0%,19.6～26.6%和13.5～17.0%。     

猕猴桃根抗肿瘤作用研究

目的评价猕猴桃根提取物的体外、内抗肿瘤活性。方法猕猴桃根活性成分的分离、纯化采用传统的天然产物化学方法,猕猴桃根先用甲醇回流提取,然后用乙酸乙酯、氯仿、正丁醇萃取。不同组分对体外培养的肿瘤细胞增殖的作用采用磺酰罗丹明B方法;猕猴桃根的体内抗肿瘤作用采用小鼠肿瘤和人肿瘤裸小鼠移植瘤模型评价。结果氯仿提取物对肿瘤细胞增殖抑制作用最强,甲醇提取物次之。体内实验证实氯仿提取物有效地抑制小鼠肝癌模型和人肝癌裸小鼠移植瘤模型的生长,抑制率大概在38.0%。结论猕猴桃根提取物有一定的抗肿瘤作用;其活性成分主要存在于极性较小的组分。     

薯蓣皂苷元衍生物的抗肿瘤活性研究

目的研究薯蓣皂苷元衍生物在体外的抗肿瘤活性。方法采用MTT法对人恶性黑色素瘤细胞A375、人肺腺癌细胞A549、人肝癌细胞HepG-2及人慢性髓原白血病细胞株K562进行体外抗肿瘤活性试验。结果薯蓣皂苷元衍生物对4个肿瘤细胞株A375、A549、K562、HepG-2具有不同程度的抗肿瘤活性。结论绝大部分薯蓣皂苷元衍生物对4个肿瘤细胞株有较好的抗肿瘤活性,IC50值都低于30μmol.L-1。化合物22对细胞株A375的IC50=4.48μmol.L-1,化合物9、10对细胞株K562的IC50分别为2.51、2.38μmol.L-1;显示其抗肿瘤活性与对照化合物1-(3β-薯蓣皂苷元)-3-苄基咪唑溴盐相当。     

Synthesis and cytotoxic properties of novel (E)-3-benzylidene-7-methoxychroman-4-one derivatives

Background and the purpose of the study

There has been increscent interest in the field of cancer chemotherapy by discovery and development of novel agents with high efficacy, low toxicity, and minimum side effects. In order to find new anticancer agents, we replaced the pyrazolone part of well-known cytotoxic agent SJ-172550 with 7-methoxychroman-4-one. Thus, a novel series of 3-benzylidene-4-chromanones were synthesized and tested in vitro against human cancer cell lines.

Methods

The title compounds were prepared by condensation of 7-methoxychroman-4-one with suitable aldehydes in appropriate alcohol in the presence of gaseous HCl. The antiproliferative activity of target compounds were evaluated against MDA-MB-231 (breast cancer), KB (nasopharyngeal epidermoid carcinoma) and SK-N-MC (human neuroblastoma) cell lines using MTT assay.

Results

Although the direct analog of SJ-172550 (compound 5d) did not show any cytotoxic activity against tested cell lines, but 2-(2-chloro-6-methoxyphenoxy)acetic acid methyl ester analog 5c showed some activity against MDA-MB-231 and SK-N-MC cells. Further modification of compound 5c resulted in the 3-chloro-4,5-dimethoxybenzylidene derivative 5b which demonstrated better cytotoxic profile against all tested cell lines (IC₅₀ values = 7.56–25.04 μg/ml).

Conclusion

The results demonstrated that the cytotoxic activity of compound 5b against MDA-MB-231 and SK-N-MC cells is more than etoposide. Therefore, compound 5b prototype could be considered as novel cytotoxic agent for further developing new anticancer chemotherapeutics.     

Antitumour activity of DX-8951f: a new camptothecin derivative

DX-8951f is a water-soluble camptothecin analogue with a unique hexacyclic structure. Compared to other current camptothecin derivatives, DX-8951f is the most effective topoisomerase I (topo I) inhibitor and has the most potent cytotoxic activity against various tumour cell lines in vitro. Of particular interest is DX-8951f's significant effect on certain tumour cell lines resistant to other camptothecin derivatives, as well as on multi-drug resistant variants that overexpress P-glycoprotein. In addition, in in vivo xenograft systems using nude mice, DX-8951f strongly inhibits the growth of human solid tumours, including resistant tumours. Its antitumour effects and resulting life prolongation in tumour-bearing mice have also been confirmed in several metastasis models. DX-8951f provides greater therapeutic efficacy and broader effective dose ranges using multiple injections than with a bolus injection and simple intermittent applications. The in vivo effects of the compound are superior to those of CPT-11 and SK&F104864, suggesting that DX-8951f is a promising therapeutic agent for the treatment of cancer patients. Phase I clinical trials are ongoing in Europe, the USA and Japan.     

Cytotoxic activity of methanol extracts from Basidiomycete mushrooms on murine cancer cell lines

Crude methanol extracts of 58 mushroom species were screened for their cytotoxic activities against two murine cancer cell lines, L1210 and 3LL, using the tetrazolium assay. A majority of extracts (74%) exhibited IC50 > 100 microg/ml against both cell lines. A most marked activity against one of the cell lines was noted for nine species (14% of the tested species). While Amanitales and Russulales tested were not found active, Polyporales and Boletales gave better results. Four species exhibited a significant cytotoxic activity (IC50 < or = 20 microg/ml) against at least one of the two murine cancer cell lines (Ganoderma lucidum, Meripilus giganteus, Suillus granulatus, S. luteus). The last one had never been investigated for its cytotoxic compounds before.     

Antitumour activity of DX-8951f: a new camptothecin derivative

DX-8951f is a water-soluble camptothecin analogue with a unique hexacyclic structure. Compared to other current camptothecin derivatives, DX-8951f is the most effective topoisomerase I (topo I) inhibitor and has the most potent cytotoxic activity against various tumour cell lines in vitro. Of particular interest is DX-8951f’s significant effect on certain tumour cell lines resistant to other camptothecin derivatives, as well as on multi-drug resistant variants that overexpress P-glycoprotein. In addition, in in vivo xenograft systems using nude mice, DX-8951f strongly inhibits the growth of human solid tumours, including resistant tumours. Its antitumour effects and resulting life prolongation in tumour-bearing mice have also been confirmed in several metastasis models. DX-8951f provides greater therapeutic efficacy and broader effective dose ranges using multiple injections than with a bolus injection and simple intermittent applications. The in vivo effects of the compound are superior to those of CPT-11 and SK&F104864, suggesting that DX-8951f is a promising therapeutic agent for the treatment of cancer patients. Phase I clinical trials are ongoing in Europe, the USA and Japan.     

Antitumor effect of kazusamycin B on experimental tumors

Kazusamycin B, a novel antibiotic (MW 542) isolated from fermentation broth of Streptomyces sp. No. 81-484 showed a broad antitumor spectrum both in vitro and in vivo. IC50 against the growth of tumor cells was around 1 ng/ml at 72 hours-exposure in vitro. Intraperitoneal injection of the antibiotic was effective in inhibiting the growth of murine tumors, S180, P388, EL-4, and B16. It was also active against doxorubicin-resistant P388, hepatic metastases of L5178Y-ML, pulmonary metastases of 3LL, and human mammary cancer MX-1 xenografted to nude mice. However, the activity of kazusamycin B toward L1210 or human lung cancer LX-1 was weaker. According to the results of comparative studies on the effect of kazusamycins B and A, an analog of B, there seemed to be no significant difference in their effectiveness. The effective dose range and toxicity were markedly dependent on tumor lines tested and the regimen used. Maximum tolerated dose in mice with subcutaneous tumors was much higher than that in mice bearing ascitic leukemia as P388. Although intermittent administration could greatly reduce the cumulative toxicity of the drug, therapeutic effect was similar with both successive and intermittent administration schedules.     

Synthesis and antiherpes virus activity of phosphate and phosphonate derivatives of 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine

A series of phosphate esters of 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG, 1) were synthesized and evaluated for antiherpes virus activity. The cyclic phosphate esters were made by a new, efficient method utilizing stannic chloride as a solubilizing agent. Monophosphate 2 and bisphosphate 4 showed comparable activity to DHPG and probably acted as prodrugs of DHPG. On the other hand, the cyclic phosphate of DHPG 3 was taken up by cells and bypassed the virus-specified thymidine kinase. As a result, 3 was active against DHPG-resistant HSV mutants that lacked the viral-specified thymidine kinase and was more toxic than DHPG to uninfected cells. The phosphonate 5, the least toxic of the derivatives tested, was only marginally active against HSV but showed substantial activity against human cytomegalovirus in vitro.     

雄黄注射液体内外抗肿瘤作用研究

目的:初步探讨雄黄注射液的体内外抗肿瘤作用。方法:采用噻唑蓝(MTT)方法观察雄黄注射液对培养的人白血病细胞株K562,人肝癌细胞株HepG-2,人胃癌细胞株MGC-803,和小鼠Lewis肺癌细胞的增殖抑制作用;建立小鼠S180腹水型肉瘤模型,采用1、2、3mg/kg剂量雄黄注射液作用于小鼠模型,观察雄黄注射液体内抗肿瘤作用。结果:MTT法显示雄黄注射液对人白血病细胞株K562,人肝癌细胞株HepG-2,人胃癌细胞株MGC-803,和小鼠Lewis肺癌细胞增殖有一定的抑制作用;灌胃给予雄黄注射液对小鼠S180腹水型肉瘤生长有一定抑制作用。结论:雄黄注射液能够抑制培养的肿瘤细胞生长,灌胃给药对S180腹水型肉瘤细胞移植的模型小鼠肿瘤增殖有明显的抑制作用。     

20-位酯化喜树碱衍生物的合成和抗肿瘤活性

目的寻找高效低毒的抗肿瘤新喜树碱酯衍生物。方法通过酰化反应合成了目标产物，用¹HNMR,IR,MS,和 HRMS确证了它们的结构；MTT法评价了目标产物的细胞毒活性；并用小鼠肝癌H₂₂肿瘤模型对这些化合物的体内抗肿瘤活性进行了评价。结果合成了12个新喜树碱衍生物。结论体内外抗肿瘤试验表明，对小鼠肝癌细胞H₂₂模型，新合成的喜树碱衍生物4的抗肿瘤活性与拓扑替康相近，但毒性低于拓扑替康。     

Synthesis and anti-tumor activities of novel pyrazolo[1,5-a]pyrimidines

A series of novel pyrazolo[1,5-a]pyrimidines were designed and synthesized in order to find novel potent anti-tumor compounds. The structures of all the compounds were confirmed by IR, (1)H-NMR, elemental analysis, and MS. Their anti-tumor activities against cancer cell lines were tested by the MTT method in vitro. Compound 19 displayed potent anti-tumor activity.     

Preparation and antifungal activity of carbamic and thiocarbamic esters of thiophenols

A series of N-substituted carbamic and thiocarbamic esters of thiophenols [substances (I leads to XLII)] was prepared and tested for in vitro antifungal activity. The substances were obtained by condensation of thiophenols with suitable isocyanates and isothiocyanates. The antifungal activity of the products was tested in vitro against the following strains: Candida albicans, Candida tropicalis, Saccharomyces cerevisiae and Trichophyton mentagrophytes. The results obtained, given in the Table I, show that the carbamic and thiocarbamic esters of the thiophenols examined have marked antifungal activity. The results give some information on structure-activity relationships and also show that in general the derivatives of dithiocarbamic acid are more active than the bioisosteric derivatives of thiocarbamic acid. Of the compounds examined the most active were esters of N-benzyl and N-allyldithiocarbamic acid.