Cytostatic and pro-apoptotic effects of a novel phenylacetate-dextran derivative (NaPaC) on breast cancer cells in interactions with endothelial cells

We have tested a novel hybrid molecule made of carboxymethylbenzylamide dextran (CMDB) and sodium phenylacetate (NaPa) groups, called the CMDB-NaPa ester (NaPaC), on the proliferation of breast cancer and endothelial cells as well as paracrine effects between these two cell types. Our results showed that NaPaC inhibited the proliferation of MDA-MB-231 cells and MCF-7 cells in a dose-dependent manner. NaPaC was 20-fold more active on highly invasive MDA-MB-231 cells than the NaPa parental molecule. On MCF-7 cells, which present a less aggressive phenotype, NaPaC was only 3-fold more active than the NaPa parental molecule. Furthermore, NaPaC had only a slight effect on the proliferation of primary cultured endothelial cells (HUVEC). A cytostatic effect of NaPaC on tumor cells was observed with cells accumulating in G0/G1 phase after 96 h of treatment. In addition, NaPaC induced a strong apoptotic effect on the two breast cancer cell lines. Conditioned media (CM) from tumor cells inhibited HUVEC proliferation, and this effect was enhanced in the presence of NaPaC (6 mM) and NaPa (10 mM). In addition to this cytostatic effect, CM from tumor cells induced a HUVEC early apoptosis which was increased, mainly, in the presence of NaPa (15 mM). Thus, this study shows that NaPaC is a more powerful anti-proliferative molecule than its parental NaPa molecule, with cytostatic and pro-apoptotic effects on MDA-MB-231 and MCF-7 tumor cells. Also, both molecules increased a pro-apoptotic effect of tumor cells on HUVEC.     

Aponecrotic, antiangiogenic and antiproliferative effects of a novel dextran derivative on breast cancer growth in vitro and in vivo

1. Since the sodium phenylacetate (NaPa) was reported to enhance the inhibitory effect of carboxymethyl benzylamide dextran (CMDB) on the breast cancer growth, we performed the esterification of CMDB with NaPa to obtain a new drug carrying the characteristics of these two components. A new molecule, phenylacetate carboxymethyl benzylamide dextran, was named NaPaC. 2. We investigated in vitro and in vivo the effects of NaPaC on MCF-7ras cell growth as well as its apoptotic and antiangiogenic effects in comparison to NaPa and CMDB. In addition, we assessed in vitro the antiproliferative effects of these drugs on other breast cancer cells, including MDA-MB-231, MDA-MB-435 and MCF-7. 3. In vitro, NaPaC inhibited MCF-7ras cell proliferation by 40% at concentration lower than that of CMDB and NaPa (12 microM vs 73 microM and 10 mM). IC(50)s were 6 and 28 microM for NaPaC and CMDB, respectively. The similar results were obtained for three other breast cancer cell lines. NaPaC reduced the DNA replication and induced cell recruitment in G(0)/G(1) phase more efficiently than its components. Moreover, it induced a cell death at concentration 1000-fold lower than NaPa. 4. In vivo, CMDB (150 mg kg(-1)) and NaPa (40 mg kg(-1)) inhibited the MCF-7ras tumour growth by 37 and 57%, respectively, whereas NaPaC (15 mg kg(-1)) decreased tumour growth by 66% without toxicity. 5. NaPa or CMDB reduced the microvessel number in tumour by 50% after 7 weeks of treatment. NaPaC had the same effect after only 2 weeks. After 7 weeks, it generated a large necrosis area without detectable microvessels. In vitro, NaPaC inhibited human endothelial cell proliferation more efficiently than CMDB or NaPa. NaPaC interacts with vascular endothelial growth factor as observed by affinity electrophoresis. 6. NaPaC acts like NaPa and CMDB but in more potent manner than components used separately. Its antiproliferative, aponecrotic and anti-angiogenic actions make it a good candidate for a new anti-cancer drug.     

Riccardin D,a Macrocyclic Bisbibenzy,Inhibits Human Breast Cancer Growth through the Suppression of Telomerase Activity

Riccardin D, a liverwort‐derived naturally occurring macrocyclic bisbibenzyl, has been found to exert anticancer effects in multiple cancer cell types. In this study, we investigated the effect and mechanism of Riccardin D on human breast cancer. Experiments were performed on human breast cancer MCF‐7 and MDA‐MB‐231 cells. The antitumour effects of Riccardin D were assessed by the 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide (MTT) assay and human breast cancer xenografts mice model. TRAPeze^® XL Telomerase Detection assay was used for the detection of telomerase activity. γ‐H₂AX foci formation was tested for the induction of DNA damage response. Cell cycle distribution was analysed by flow cytometry, and cell apoptosis was determined by annexin V‐FITC/PI staining, terminal deoxynucleotidyl transferase‐mediated dUTP nick end labelling (TUNEL) assay and Western blotting. Riccardin D effectively inhibited the growth of MCF‐7 and MDA‐MB‐231 cells in vitro. And Riccardin D also effectively delayed the growth of MCF‐7 and MDA‐MB‐231‐luc‐D3H2LN xenografts without significant loss of body‐weight. Further analysis suggested that Riccardin D's effects may arise from its suppression of telomerase activity, which led to telomere dysfunction. Telomerase inhibition and telomere dysfunction could activate the canonical ataxia telangiectasia‐mutated (ATM) kinase‐mediated DNA damage response, as shown by elevated expression of γ‐H₂AX, p‐ATM and p‐Chk2. This is finally followed by the induction of cell cycle arrest and apoptosis, as shown by the increase of TUNEL‐stained cells, caspase activation, PARP cleavage and the increase of bax/bcl‐2 ratio. Moreover, Riccardin D induced p53‐proficient MCF‐7 cells to arrest in G1 phase and p53‐deficient MDA‐MB‐231 cells to arrest in G2/M phase. Overall, these results demonstrate that Riccardin D may inhibit human breast cancer growth through suppression of telomerase activity.     

肝素对乳腺癌细胞-MCF-7的抗增殖作用

目的　观察肝素对乳腺癌细胞的抗增殖作用。方法　MCF 7、MDA MB 2 31人乳腺上皮癌细胞培养 ,细胞计数。结果　肝素 40mg·L-1可明显抑制MCF 7细胞的生长 ,该抑制作用受血清的影响。结论　肝素能抑制在有血清培养条件下的MCF 7人乳腺上皮癌细胞的生长。     

Effects of the binding of a dextran derivative on fibroblast growth factor 2: secondary structure and receptor-binding studies.

CMDB (carboxymethyldextran-benzylamide) are dextrans statistically substituted with carboxymethyl and benzylamide groups which can mimick some of the biological properties of heparin. It has previously been shown that CMDB inhibit autocrine growth of breast tumor cells (Bagheri-Yarmand et al., Biochem. Biophys. Res. Commun. 239: 424-428, 1997) and selectively displace fibroblast growth factor 2 (FGF-2) from its receptor. Here, we used circular dichroism and fluorescence anisotropy measurements to show that the conformation of FGF-2 was significantly altered upon its binding to CMDB and to short CMDB fragments prepared within this study. CMDB and fragments formed a stable 1:1 complex with FGF-2, with affinities being estimated as 20+/-10 nM from fluorescence anisotropy analysis. No such a complex was formed with insulin-like growth factor (IGF-1) or epidermal growth factor (EGF). CMDB competed with the FGF-2 receptor for binding to FGF-2 but did not disturb the binding of IGF-1 and EGF to their receptors. Thus, our results highlight the selectivity of CMDB and their fragments towards FGF-2. Heparin, however, competes with CMDB and their fragments for binding to FGF-2. The carboxymethyl and benzylamide groups of these molecules likely interact directly with a heparin-binding region of FGF-2. The resulting change in conformation disturbs the binding of FGF-2 to its receptor and consecutively its mitogenic activity.     

铜绿假单胞茵注射液对人乳腺癌细胞的体外杀伤及促凋亡作用研究

目的研究铜绿假单胞菌（pseudo—monas aeruginosa,PA-MSHA）注射液在体外实验中对人乳腺癌细胞（MCF-7）凋亡和增殖的影响,并探讨其可能的作用机制。方法应用MTT比色法检测铜绿假单胞菌注射液对体外培养的MCF-7细胞增殖抑制作用,应用流式细胞术检测铜绿假单胞菌注射液诱导乳腺癌细胞凋亡,检测其对细胞周期的影响。用Hoechst33258染色法染色,荧光显微镜检测铜绿假单胞菌注射液诱导体外培养的MCF-7肿瘤细胞凋亡的形态学改变。结果铜绿假单胞菌注射液抑制MCK7细胞增殖,呈剂量和时间依赖性;与对照组相比,铜绿假单胞菌注射液组MCF7细胞的凋亡率明显增高（P〈0．01）、G0／G1期细胞比例明显增高、S期细胞所占百分比明显降低（P〈0．05）,染色荧光显微镜检测发现PAMSHA能诱导体外培养的肿瘤细胞呈现明显的凋亡图像。结论铜绿假单胞菌注射液可能通过对细胞周期中G0／G1期阻滞,诱导MCF-7细胞凋亡,从而抑制MCF-7细胞的增殖。     

Inhibitory effect of agmatine on proliferation of tumor cells by modulation of polyamine metabolism

Aim: To assess the inhibitory effect of agmatine on tumor growth in vivo and tumor cell proliferation in vitro. Methods: The transplanted animal model,[^3H]thymidine incorporation assay, 3-[4,5-dimethythiazol-2-yl]-2,5-diphenyltetrazolium assay, and lactate dehydrogenase (LDH) release assay were performed.Results: Agmatine, at doses of 5-40mg/kg, suppressed the S180 sarcoma tumor growth dose-dependently in mice in vivo and the highest inhibitory ratio reached 31.3% in Kunming mice and 50.0% in Balb/c mice, respectively. Similar results were obtained in the transplanted B16 melanoma tumor model. Agmatine (1-1000μmol/L) was able to attenuate the proliferation of cultured MCF-7 human breast cancer cells in vitro in a concentration-dependent manner and the highest inhibitory ratio reached 50.3% in the [^3H]thymidine incorporation assay.Additionally, in the LDH release assay, spermine (20μmol/L) and spermidine (20μmol/L) increased the LDH release significantly, but agmatine (1-1000μmol/L) did not, indicating that the inhibitory effect of agmatine on the proliferation of MCF was not related to cellular toxicity. In the [^3H]thymidine incorporation assay,putrescine (12.5-100.0μmol/L) could reverse the inhibitory effect of agmatine on the proliferation of MCF concentration-dependently, suggesting that the inhibitory effect of agmatine on the proliferation of MCF might be associated with a decreased level of the intracellular polyamines pool. Conclusion: Agmatine had significant inhibitory effect on transplanted tumor growth in vivo and proliferation of tumor cells in vitro, and the mechanism might be a result of inducing decrease of intracellular polyamine contents.     

用高通量药物筛选系统研究葡聚糖衍生物的抗乳腺癌活性

目的 研究葡聚糖衍生物对乳腺癌的作用. 方法 以肝素表达缺陷而稳定表达成纤维细胞生长因子受体（FGFR）的F32细胞系和乳腺癌细胞系MCF-7、MCF-7ras为模型,利用³H-thymidine摄入技术,研究人工合成的葡聚糖衍生物对细胞生长的影响,并初步探讨其作用机制. 结果 葡聚糖衍生物能够有效作用于HS/FGF/FGFR复合物,但对两种乳腺癌细胞系具有完全相反的两种作用,即刺激MCF-7的生长而对MCF-7ras则抑制生长.构效研究发现,磺酸基团和苯环是影响葡聚糖衍生物活性重要基团. 结论 葡聚糖衍生物与肝素具有相似的性质,对细胞生长具有双重性.     

Sodium propionate exerts anticancer effect in mice bearing breast cancer cell xenograft by regulating JAK2/STAT3/ROS/p38 MAPK signaling

Propionate is a short-chain fatty acid (SCFA) mainly produced from carbohydrates by gut microbiota. Sodium propionate (SP) has shown to suppress the invasion in G protein-coupled receptor 41 (GPR41) and GPR43-overexpressing breast cancer cells. In this study we investigated the effects of SP on the proliferation, apoptosis, autophagy, and antioxidant production of breast cancer cells. We showed that SP (5−20 mM) dose-dependently inhibited proliferation and induced apoptosis in breast cancer cell lines JIMT-1 (ER-negative and HER2-expressing) and MCF7 (ER-positive type), and this effect was not affected by PTX, thus not mediated by the GPR41 or GPR43 SCFA receptors. Meanwhile, we demonstrated that SP treatment increased autophagic and antioxidant activity in JIMT-1 and MCF7 breast cancer cells, which might be a compensatory mechanism to overcome SP-induced apoptosis, but were not sufficient to overcome SP-mediated suppression of proliferation and induction of apoptosis. We revealed that the anticancer effect of SP was mediated by inhibiting JAK2/STAT3 signaling which led to cell-cycle arrest at G₀/G₁ phase, and increasing levels of ROS and phosphorylation of p38 MAPK which induced apoptosis. In nude mice bearing JIMT-1 and MCF7 cells xenograft, administration of SP (20 mg/mL in drinking water) significantly suppressed tumor growth by regulating STAT3 and p38 in tumor tissues. These results suggest that SP suppresses proliferation and induces apoptosis in breast cancer cells by inhibiting STAT3, increasing the ROS level and activating p38. Therefore, SP is a candidate therapeutic agent for breast cancer.     

斯托斯普林增强X-射线的作用与机制研究

目的探索斯托斯普林(staurosporine,STP)对X-射线的增敏作用及机制。方法用克隆测定法、流式细胞术和Western Blotting检测。结果X-射线照射后HT-29和MCF-7/ADR细胞明显阻滞于G₂期,STP可以清除X-射线引起的G₂期阻滞,并有明显的增敏作用。进一步研究显示,细胞在受到X-射线照射后,cyclin B1表达水平和分裂指数均明显降低;用STP处理后,cyclin B1的表达水平和分裂指数均明显增高。表明其增敏机制之一是上调受照射细胞的cyclin B1表达水平,从而激活cyclin B1/cdc2复合物,促使细胞由G₂期进入M期,减弱细胞的修复水平。结论 STP是一种有效的G₂期关卡清除剂,能明显增加X-射线对肿瘤细胞的作用。     

肝素在治疗胎儿生长受限中的应用

目的 探讨肝素在胎儿生长受限中的应用价值.方法 选择胎儿生长受限(FGR)患者108例,观察组和对照组各54例,前者用低分子右旋糖酐加肝素治疗,后者用低分子右旋糖酐加丹参治疗,比较二者治疗后宫高增长、胎儿双顶径、股骨长增长及胎儿生物理评分改善情况.结果 观察组在宫高增长、胎儿双顶径及股骨长增长均显著高于对照组(P＜0.05);观察组在生物物理评分改善情况上明显高于对照组(P＜0.05).结论 小剂量肝素可治疗胎儿宫内生长受限,且安全有效.     

Oestrogenic and androgenic activity of triclosan in breast cancer cells

As a consequence of its widespread use as an antimicrobial agent in consumer goods, triclosan has become distributed ubiquitously across the ecosystem, and recent reports that it can cause endocrine disruption in aquatic species has increased concern. It is reported here that triclosan possesses intrinsic oestrogenic and androgenic activity in a range of assays in vitro which could provide some explanation for the endocrine disrupting properties described in aquatic populations. In terms of oestrogenic activity, triclosan displaced [(3)H]oestradiol from oestrogen receptors (ER) of MCF7 human breast cancer cells and from recombinant human ER alpha/ER beta. Triclosan at 10(-5) m completely inhibited the induction of the oestrogen-responsive ERE-CAT reporter gene in MCF7 cells by 10(-10) m 17beta-oestradiol and the stimulation of growth of MCF7 human breast cancer cells by 10(-10) m 17beta-oestradiol. On its own, 1 microm triclosan increased the growth of MCF7 cells over 21 days. Triclosan also had androgenic activity. It displaced [(3)H]testosterone from binding to the ligand binding domain of the rat androgen receptor (AR). Triclosan was able to inhibit the induction of the androgen-responsive LTR-CAT reporter gene in S115 mouse mammary tumour cells by 10(-9) m testosterone and in T47D human breast cancer cells by 10(-8) m testosterone at concentrations of 10(-7) m and 10(-6) m, respectively. Triclosan at 2 x 10(-5) m antagonized the stimulation of the growth of S115+A mouse mammary tumour cells by 10(-9) m testosterone. The finding that triclosan has oestrogenic and androgenic activity warrants further investigation in relation to both endocrine disruption of aquatic wildlife and any possible impact on human health.     

土贝母皂苷-Ⅱ对人肝癌细胞HepG2增殖及细胞周期的影响

目的探讨土贝母皂苷-Ⅱ对人肝癌细胞HepG2增殖、细胞周期的影响及其抗肿瘤效应。方法用不同浓度土贝母皂苷-Ⅱ0、2、4、6、8、10、12μg/ml处理HepG2细胞后,MTT法检测细胞生长的抑制率,荧光染色和流式细胞术分别观察凋亡细胞形态和细胞周期的变化。同时,以H22肝癌小鼠模型初步探讨土贝母皂苷-Ⅱ的抗肿瘤作用。结果土贝母皂苷-Ⅱ能剂量依赖性地抑制HepG2细胞生长,24-h半数抑制剂量(IC50)为4.05μg/ml。HepG2细胞经土贝母皂苷-Ⅱ处理后,呈现典型的凋亡细胞形态,G2/M期细胞数量增加,而G0/G1期细胞数明显减少。体内抗肿瘤实验结果证明,土贝母皂苷-Ⅱ对肿瘤的生长有显著的抑制作用。结论土贝母皂苷-Ⅱ可能是通过使肿瘤细胞滞留于G2/M期,从而抑制肿瘤细胞的增殖。     

Basement membrane components (matrigel) promote the tumorigenicity of human breast adenocarcinoma MCF7 cells and provide an in vivo model to assess the responsiveness of cells to estrogen.

The ability to transplant human tumors into athymic nude mice allows studies of tumor cells in vivo. However, after s.c. injection the incidence of tumor and metastases in nude mice is frequently low. We have studied the tumorigenicity in nude mice of estradiol (E2)-sensitive breast adenocarcinoma MCF7 cells. Matrigel, an extract of basement membrane proteins, induces rapid tumor development after s.c. injection of MCF7 cells. In the absence of this matrice, MCF7 cells failed to induce tumor growth. In this in vivo model, MCF7 cells were analysed for their E2 sensitivity. Two weeks after inoculation in the presence of matrigel, cells formed growing tumors in intact mice supplemented with E2. In ovariectomized or untreated mice, tumor appearance was delayed and the growth level was very low. Thus, MCF7 cells formed tumors in the absence of E2 but retained in vivo their responsiveness to estrogen. Growing human tumors in nude mice provides a rapid and useful model for testing the sensitivity of cells to hormone.     

Effect of tumor necrosis factor on human tumor cell lines sensitive and resistant to cytotoxic drugs, and its interaction with chemotherapeutic agents

We investigated the cytotoxic effects of recombinant tumor necrosis factor (TNF) alone and in combination with interferon-gamma (IFN-gamma) and/or cytotoxic drugs on a variety of human tumor cell lines (U937, IGROV-1, HT29, LoVo, MCF7 and U20S), including cell lines with in vitro acquired resistance (LoVo/DX and MCF7/DX selected for resistance to doxorubicin (DX) and characterized by pleiotropic drug resistance; U20S selected for resistance to cisplatin (CDDP], using MTT assay. U937 and MCF7 were sensitive to the cytotoxic effect of TNF, whereas all the other cells were insensitive up to 1000 U/ml (the maximum tested dose). Surprisingly, TNF was cytotoxic (30-40% cytotoxicity) against two resistant lines (LoVo/DX and U20S/Pt) but not against the parent sensitive lines. Treatment with increasing doses of TNF after 6 h incubation with a subtoxic concentration of IFN-gamma produced a synergistic effect in four cell lines (U937, HT29, LoVo/DX and MCF7), whereas in the other five the cell killing of the combination was comparable with that achieved by TNF alone. The combination of subtoxic doses of TNF and increasing doses of drugs targeted at DNA topoisomerase II (i.e. DX, actinomycin D and VP16) produced an additive cytotoxic effect in all cell lines. The same results were obtained combining TNF and CDDP, except in U20S/Pt cells in which TNF synergistically increased CDDP cytotoxicity. The combination of TNF and IFN-gamma enhanced cytotoxicity about 20-fold for DX and 6-fold for CDDP, evaluated in terms of the modification index, against LoVo/DX and U20S/Pt cells respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

败酱草单萜环烯醚酯类对HepG2、MCF7细胞增殖及凋亡的影响

目的 探讨败酱草单萜环烯醚酯类（patrinia monoterpene iridoid ether esters,PMIEE）对HepG2和MCF7细胞增殖抑制和凋亡的影响。方法 HepG2和MCF7细胞经PMIEE作用后,采用CCK8法检测细胞增殖抑制情况;Annexin V-FITC/PI双标记流式细胞术检测细胞凋亡及周期情况;细胞划痕实验检测细胞迁移状况;Western blot法检测Bcl-2、Bax、caspase3、cdc2和CyclinB1的表达情况。结果 CCK8、划痕实验和Annexin V-FITC/PI流式细胞术检测显示,PMIEE对HepG2和MCF7细胞均有显著的增殖抑制、促凋亡率和降低迁移率作用（P<0.05）,呈一定量效关系,且PMIEE对HepG2细胞的周期阻滞以G2/M期为主,MCF7细胞以G0/G1期为主;Western blot结果显示,PMIEE可显著下调2种细胞Bcl-2、cdc2、CyclinB1的表达,上调Bax和caspase3的表达水平。结论 PMIEE可诱导HepG2和MCF7细胞增殖抑制和凋亡,下调Bcl-2、cdc2和CyclinB1表达及上调Bax和caspase3表达,其抗癌的潜在机制可能与此有关。     

Activity of MDI-301, a novel synthetic retinoid, in xenografts

The efficacy of MDI-301, a non-toxic novel synthetic retinoid, was found to be equivalent to the natural 9-cis-retinoic acid (RA) in vitro against estrogen-dependent MCF7 and T47D breast cancer cell lines which express RA receptor (RAR) alpha. Both retinoids also showed similar efficacy against established PC-3 prostate carcinoma xenografts. MCF7 tumor xenografts showed a reduction in tumor growth of 48% without systemic side-effects upon treatment with MDI-301 compared with MCF7 controls. Tumor xenografts derived from MDA-MB-231, an estrogen-independent breast cancer cell line that expresses low levels of RARalpha, were unresponsive. This study demonstrates that MDI-301 is as efficacious as 9-cis-RA against cancer cells with RARalpha, with no signs of toxicity in vivo, making it a potential candidate for cancer therapy.