Myosin light chain kinase is responsible for high proliferative ability of breast cancer cells via antiapoptosis involving p38 pathway

Aim:

To investigate whether myosin light chain kinase (MLCK) contributed to the high proliferative ability of breast cancer cells.

Methods:

Soft agar colony formation on the MCF-7 and LM-MCF-7 cell lines was determined. The cell cycles of MCF-7 and LM-MCF-7 were detected using flow cytometry analysis. Western blot analysis was performed to detect the expression levels of p-ERK1/2, total-ERK1/2, p-p38, total p38, p-JNK, total-JNK, survivin, Bcl-2, p-MLC, caspase-9, cleaved caspase-9, and MLCK. After treatment with adriamycin (ADR), ML-7 and SB203580, apoptosis was examined using flow cytometry analysis and Annexin V-FITC fluorescence microscopy.

Results:

The breast cancer LM-MCF-7 cell line with high metastasis potential (a metastitic sub-clone of MCF-7) had higher anti-apoptosis ability relative to MCF-7 cells in response to adriamycin treatment (apoptosis rate: 6.76% vs 28.58%, P<0.05). Moreover, the expression level of MLCK was upregulated and the level of phosphorylated p38 (p-p38) was decreased in LM-MCF-7 cells. Flow cytometry analysis showed that ML-7, selective inhibitor of MLCK, could induce apoptosis of the LM-MCF-7 cells, in which the level of p-p38 was increased. Meanwhile, the expression levels of Bcl-2 and survivin were downregulated, while the caspase-9 was upregulated suggesting that the cells were undergone apoptosis. Flow cytometry analysis showed that SB203580, an inhibitor of p38, abolished ML-7-induced apoptosis, which resulted in the upregualtion of Bcl-2 and survivin, and downregulation of caspase-9, suggesting that Bcl-2, survivin and caspase-9 are downstream effectors of p38.

Conclusion:

MLCK is responsible for high proliferative ability of breast cancer cells through anti-apoptosis, in which p38 pathway was involved.     

Growth inhibition, G1-arrest, and apoptosis in MCF-7 human breast cancer cells by novel highly lipophilic 5-fluorouracil derivatives

In this study we evaluate the antitumour activity, the cell cycle arrest and apoptotic properties of novel lipophilic benzene-fused seven-membered 5-fluorouracil (5-FU) analogs in comparison to 5-FU on MCF-7 human breast cancer cells. The lipophilicities of ESB-786B, ESB-252A and ESB-928A were predicted by using the CDR option of the PALLAS 2.0 program. Cytotoxic assays were evaluated in MCF-7 cells treated with the sulforhodamine B colorimetric method. Cell cycle perturbations were studied by flow cytometry. Apoptosis was determined by both DNA fragmentation and annexin V-FITC and propidium iodide staining. The novel derivatives were more lipophilic than 5-FU and induced a marked growth inhibition, in a dose-dependent manner. After treatment with IC(50) value (ranged from 2.5 to 22 microM) for each compound, light microscopy observation showed modifications in the morphology of MCF-7 cells. In addition, the 5-FU analogs arrest cells in the G(0)/G(1) phase of the cell cycle whereas 5-FU induced arrest in S-phase. Moreover, induction of apoptosis was demonstrated by the annexin-V-based assay and confirmed using DNA fragmentation analysis on MCF-7 cells, a cell line in which the induction of DNA laddering is very difficult. The novel benzannelated seven-membered 5-FU analogs can be considered as specific apoptotic inducers. These experimental findings provide support for the use of these novel compounds as new weapons in the fight against breast cancer.     

4-肼基苯磺酸特异性抑制SHP-2激活突变的乳腺癌细胞增殖

目的研究4-肼基苯磺酸对SHP-2激活突变的乳腺癌MDA-MB-231细胞株增殖的特异性抑制作用,为新型抗乳腺癌药物的开发提供些许参考。方法不同浓度的4-肼基苯磺酸处理SHP-2激活突变的MDA-MB-231细胞,用MTT法检测细胞的增殖。结果 4-肼基苯磺酸对乳腺癌MDA-MB-231细胞株的增殖有明显抑制作用,并呈剂量依赖性;同时对SHP-2低活性的对照组细胞无明显作用。结论 4-肼基苯磺酸可特异性地抑制SHP-2激活突变的乳腺癌MDA-MB-231细胞的体外增殖,这种抑制效果应是通过特异性抑制SHP-2异常增高的磷酸酶活性来实现的。     

槲皮素通过靶向GAS5/Notch1信号通路促进乳腺癌细胞凋亡的研究

目的探讨槲皮素对乳腺癌细胞促凋亡作用的可能机制。方法用槲皮素处理乳腺癌MCF-7细胞后,采用MTT法检测细胞活力;平板克隆实验检测细胞增殖克隆能力;Annexin V-FITC/PI双染法检测细胞凋亡;同时,分别采用槲皮素(40、80、160μmol·L^-1)、GAS5小干扰RNA(siGAS5)、槲皮素(80μmol·L^-1)协同siGAS5处理细胞后,qRT-PCR法和Western blot法检测GAS5、Notch1、Jagged1、Hes1、Bcl-2、Bax、Caspase-3的表达。结果槲皮素(40、80、160μmol·L^-1)处理MCF-7细胞后,发现40μmol·L^-1槲皮素可明显抑制增殖,而80、160μmol·L^-1槲皮素不仅明显抑制增殖且诱导凋亡;槲皮素(40、80、160μmol·L^-1)可上调GAS5、Bax和Caspase-3的表达,下调Notch1、Jagged1、Hes1和Bcl-2的表达;细胞转染siGAS5后,与sncRNA组相比,GAS5、Bax和Caspase-3表达下调,Notch1、Jagged1、Hes1和Bcl-2表达上调;当siGAS5与槲皮素(80μmol·L^-1)共处理细胞后,与sncRNA加槲皮素对照组相比,GAS5、Bax和Caspase-3表达下调,Notch1、Jagged1、Hes1和Bcl-2上调。结论槲皮素通过靶向GAS5/Notch1信号通路促进乳腺癌细胞凋亡。     

A nitric oxide/Ca(2+)/calmodulin/ERK1/2 mitogen-activated protein kinase pathway is involved in the mitogenic effect of IL-1beta in human astrocytoma cells

Background and purpose:

Evidence is accumulating to support a role for interleukin-1β (IL-1β) in astrocyte proliferation. However, the mechanism by which this cytokine modulates this process is not fully elucidated.

Experimental approach:

In this study we used human astrocytoma U-373MG cells to investigate the role of nitric oxide (NO), intracellular Ca²⁺ concentration ([Ca²⁺]_i), and extracellular signal-regulated protein kinase (ERK) in the signalling pathway mediating IL-1β-induced astrocyte proliferation.

Key results:

Low IL-1β concentrations induced dose-dependent ERK activation which paralleled upregulation of cell division, whereas higher concentrations gradually reversed both these responses by promoting apoptosis. Pretreatment with the nonspecific NOS inhibitor, N-ω-nitro-l-arginine methyl ester (L-NAME) or the selective iNOS inhibitor, N-[[3-(aminomethyl)phenyl]methyl]-ethanimidamide dihydrochloride (1400W), antagonized ERK activation and cell proliferation induced by IL-1β. Inhibition of cGMP formation by the guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), partially inhibited ERK activation and cell division. Functionally blocking Ca²⁺ release from endoplasmic reticulum with ryanodine or 2-aminoethoxydiphenylborane (2-APB), inhibiting calmodulin (CaM) activity with N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide hydrochloride (W7) or MAPK kinase activity with 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthiol]butadiene (U0126) downregulated IL-1β-induced ERK activation as well as cell proliferation. The cytokine induced a transient and time-dependent increase in intracellular NO levels which preceded elevation in [Ca²⁺]_i.

Conclusions and implications:

These data identified the NO/Ca²⁺/CaM/ERK signalling pathway as a novel mechanism mediating the mitogenic effect of IL-1β in human astrocytes. As astrocyte proliferation is a hallmark of reactive astrogliosis, our results reveal a new potential target for therapeutic intervention in neuroinflammatory disorders.     

Transforming growth factor β‐activated kinase 1 inhibitor suppresses the proliferation in triple‐negative breast cancer through TGF‐β/TGFR pathway

Breast cancer is one of the most invasive cancer types in female population. The functional activity of Transforming growth factor β‐activated kinase 1 (TAK1) in breast cancer progression increasingly attracts attention as it provides a potential target for antibreast cancer drug development. However, the fundamental role of TAK1 for triple‐negative breast cancer (TNBC) progression and the effect of potential anti‐TAK1 drug candidate needs to be further evaluated. Herein, we focused on the role of TAK1 in human breast cancer cells, and we hypothesized that the inhibition of TAK1 activation can repress the growth of human TNBC cells. We found that the TAK1 is robustly activated within cancer cell population of clinic‐derived TNBC samples and the human breast cancer cell lines in culture. Furthermore, we determined the effect of 5Z‐7‐oxozeaenol (5Z‐O), a TAK1‐specific small molecule inhibitor, on proliferation of human TNBC cell line. 5Z‐O treatment significantly suppressed the proliferation of human TNBC cells. Collectively, these demonstrate the role of TAK1 in human breast cancer and the antiproliferate effect of TAK1 inhibitor. Our study sets the stage for further research on TAK1 as a promising target for development of anti‐TNBC drugs and therapeutic strategies.     

Identification of 5-lipoxygenase and microsomal prostaglandin E2 synthase-1 as functional targets of the anti-inflammatory and anti-carcinogenic garcinol

Garcinol (camboginol) from the fruit rind of Guttiferae species shows anti-carcinogenic and anti-inflammatory properties, but the underlying molecular mechanisms are unclear. Here we show that garcinol potently interferes with 5-lipoxygenase (EC 7.13.11.34) and microsomal prostaglandin (PG)E₂ synthase (mPGES)-1 (EC 5.3.99.3), enzymes that play pivotal roles in inflammation and tumorigenesis. In cell-free assays, garcinol inhibited the activity of purified 5-lipoxygenase and blocked the mPGES-1-mediated conversion of PGH₂ to PGE₂ with IC₅₀ values of 0.1 and 0.3 μM, respectively. Garcinol suppressed 5-lipoxygenase product formation also in intact human neutrophils and reduced PGE₂ formation in interleukin-1β-stimulated A549 human lung carcinoma cells as well as in human whole blood stimulated by lipopolysaccharide. Moreover, garcinol interfered with isolated cyclooxygenase (COX)-1 (EC 1.14.99.1, IC₅₀ = 12 μM) and with the formation of COX-1-derived 12(S)-hydroxy-5-cis-8,10-trans-heptadecatrienoic acid and thromboxane B₂ in human platelets. In contrast, neither Ca²⁺-ionophore (A23187)-induced arachidonic acid release in neutrophils nor COX-2 activity in A549 cells or whole blood, measured as formation of 6-keto PGF_1α, or isolated human recombinant COX-2 were significantly affected by garcinol (≤30 μM). Together, the high potency of garcinol to selectively suppress PGE₂ synthesis and 5-lipoxygenase product formation provides a molecular basis for the anti-inflammatory and anti-carcinogenic effects of garcinol and rationalizes its therapeutic use.     

西黄丸调节JNK1/AP-1通路抑制荷4T1小鼠乳腺癌细胞生长

目的 研究西黄丸抑制荷4T1小鼠乳腺癌肿瘤的生长及其可能机制。方法 建立荷4T1小鼠乳腺癌模型,以低、中、高剂量（0.39、0.78、1.95 g/kg） ig给予西黄丸两周,分离肿瘤组织,称质量并计算抑瘤率;切片,TUNEL染色检测肿瘤细胞凋亡;实时荧光定量PCR （qRT-PCR）检测肿瘤组织JNK1、AP-1 mRNA表达;免疫荧光染色和Western Blotting检测肿瘤组织中JNK1、AP-1蛋白表达。结果 与模型组比较,肿瘤质量随西黄丸剂量的升高显著下降;TUNEL荧光染色结果显示,肿瘤细胞凋亡数量随西黄丸剂量的升高显著升高;qRT-PCR结果显示,肿瘤组织中JNK1、AP-1 mRNA表达水平随西黄丸剂量的升高显著上调;免疫荧光染色和Western Blotting结果显示,肿瘤组织中JNK1、AP-1蛋白表达随西黄丸剂量的升高显著增加;且高、中、低剂量组差异均具有统计学意义（P<0.05）。结论 西黄丸显著抑制肿瘤生长,其作用机制与激活JNK1/AP-1信号通路促进肿瘤细胞凋亡相关。     

Inhibition of lipopolysaccharide-stimulated NO production by a novel synthetic compound CYL-4d in RAW 264.7 macrophages involving the blockade of MEK4/JNK/AP-1 pathway

In the present study, a novel synthetic compound 4-(2-(cyclohex-2-enylidene)hydrazinyl)quinolin-2(1H)-one (CYL-4d) was found to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) production without affecting cell viability or enzyme activity of expressed inducible NO synthase (iNOS) in RAW 264.7 macrophages. CYL-4d exhibited parallel inhibition of LPS-induced expression of iNOS protein, iNOS mRNA and iNOS promoter activity in the same concentration range. LPS-induced activator protein-1 (AP-1) DNA binding, AP-1-dependent reporter gene activity and c-Jun nuclear translocation were all markedly inhibited by CYL-4d with similar efficacy, whereas CYL-4d produced a weak inhibition of nuclear factor-kappaB (NF-kappaB) DNA binding, NF-kappaB-dependent reporter gene activity and p65 nuclear translocation without affecting inhibitory factor-kappa B alpha (I kappa B alpha) degradation. CYL-4d had no effect on the LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and its upstream activator MAPK kinase (MEK) 3, whereas it significantly attenuated the phosphorylation of c-Jun, c-Jun NH(2)-terminal kinase (JNK) and its upstream activator MEK4 in a parallel concentration-dependent manner. Other Toll-like receptors (TLRs) ligands (peptidoglycans, double-stranded RNA, and oligonucleotide containing unmethylated CpG motifs)-induced iNOS protein expression were also inhibited by CYL-4d. Furthermore, the NO production from BV-2 microglial cells as well as rat alveolar macrophages in response to LPS was diminished by CYL-4d. These results indicate that the blockade of NO production by CYL-4d in LPS-stimulated RAW 264.7 cells is attributed mainly to interference in the MEK4-JNK-AP-1 signaling pathway. CYL-4d inhibition of NO production is not restricted to TLR4 activation and immortalized macrophage-like cells.     

hnRNP A2/B1在乳腺癌组织中表达水平及其凋亡调控的研究

目的 检测乳腺癌组织标本中hnRNP A2/B1的表达水平;探讨hnRNP A2/B1基因对乳腺癌细胞株MCF-7凋亡的影响.方法 选取乳腺癌患者40例、乳腺纤维瘤患者20例(对照),采用免疫组化方法检测组织中hnRNP A2/B1的表达水平;体外培养乳腺癌细胞株MCF-7,并将hnRNP A2/B1 siRNA转染至MCF-7中,TUNEL法检测转染前后MCF-7细胞的凋亡情况.结果 40例乳腺癌组织标本中36例有hnRNP A2/B1阳性表达,而作为对照的乳腺纤维瘤组织中只有3例有hnRNP A2/B1阳性表达,乳腺纤维瘤组与乳腺癌组hnRNP A2/B1表达水平差异有统计学意义(P＜0.01).体外培养乳腺癌细胞MCF-7在转染hnRNP A2/B1 siRNA后,MCF-7细胞凋亡明显增加.结论 hnRNP A2/B1在乳腺癌组织中的表达较乳腺纤维瘤组织高,推测hnRNP A2/B1与乳腺癌的发生有关.通过siRNA干预、降低hnRNP A2/B1的表达水平可以促进乳腺癌细胞凋亡,提示hnRNP A2/B1可能通过抗肿瘤细胞失巢凋亡实现肿瘤的发生.     

Psoralidin, a dual inhibitor of COX-2 and 5-LOX, regulates ionizing radiation (IR)-induced pulmonary inflammation

Radiotherapy is the most significant non-surgical cure for the elimination of tumor, however it is restricted by two major problems: radioresistance and normal tissue damage. Efficiency improvement on radiotherapy is demanded to achieve cancer treatment. We focused on radiation-induced normal cell damage, and are concerned about inflammation reported to act as a main limiting factor in the radiotherapy. Psoralidin, a coumestan derivative isolated from the seed of Psoralea corylifolia, has been studied for anti-cancer and anti-bacterial properties. However, little is known regarding its effects on IR-induced pulmonary inflammation. The aim of this study is to investigate mechanisms of IR-induced inflammation and to examine therapeutic mechanisms of psoralidin in human normal lung fibroblasts and mice. Here, we demonstrated that IR-induced ROS activated cyclooxygenases-2 (COX-2) and 5-lipoxygenase (5-LOX) pathway in HFL-1 and MRC-5 cells. Psoralidin inhibited the IR-induced COX-2 expression and PGE₂ production through regulation of PI3K/Akt and NF-κB pathway. Also, psoralidin blocked IR-induced LTB₄ production, and it was due to direct interaction of psoralidin and 5-lipoxygenase activating protein (FLAP) in 5-LOX pathway. IR-induced fibroblast migration was notably attenuated in the presence of psoralidin. Moreover, in vivo results from mouse lung indicate that psoralidin suppresses IR-induced expression of pro-inflammatory cytokines (TNF-α, TGF-β, IL-6 and IL-1 α/β) and ICAM-1. Taken together, our findings reveal a regulatory mechanism of IR-induced pulmonary inflammation in human normal lung fibroblast and mice, and suggest that psoralidin may be useful as a potential lead compound for development of a better radiopreventive agent against radiation-induced normal tissue injury.     

circMTO1调控Wnt/β-catenin抑制乳腺癌细胞增殖和转移能力的机制研究

目的 研究环状RNA MTO1（circMTO1）对乳腺癌细胞增殖和转移的影响及其可能机制。方法 收集102例浸润性乳腺癌患者的癌组织及癌旁组织,选用乳腺癌细胞系MDA-MB-231、HCC-70、MCF-7和人乳腺正常细胞系MCF-10A,采用荧光定量PCR（qPCR）检测circMTO1在乳腺癌组织和细胞系中的表达水平。分别构建circMTO1过表达和circMTO1敲减质粒转染乳腺癌细胞系,分为NC组、oe-circMTO1组和sh-circMTO1组,qPCR检测转染效果。MTS实验检测各组细胞增殖能力,Transwell实验检测各组细胞转移能力。TOP/FOP荧光素酶实验检测各组细胞Wnt/β-catenin信号通路活性,Western blot检测各组细胞Wnt/β-catenin信号通路相关蛋白Wnt3a、β-catenin、cMyc、Cyclin D1和基质金属蛋白酶7（MMP7）的表达。结果 与癌旁组织和人正常乳腺细胞系相比,circMTO1在乳腺癌组织和乳腺癌细胞系中的相对表达量降低（P<0.05）。有淋巴结转移和TNM分期为Ⅲ期的乳腺癌患者组织中circMTO1的相对表达水平较低（P<0.05）。与NC组相比,oe-circMTO1组circMTO1相对表达量增加,细胞的增殖、转移能力以及Wnt/β-catenin信号通路活性减弱,Wnt3a、β-catenin、cMyc、Cyclin D1和MMP7蛋白表达水平降低（P<0.05）;sh-circMTO1组circMTO1相对表达量降低,细胞的增殖、转移能力以及Wnt/β-catenin信号通路活性增强,Wnt3a、β-catenin、cMyc、Cyclin D1和MMP7蛋白表达水平增加（P<0.05）。结论 circMTO1在乳腺癌细胞中呈低表达,circMTO1通过抑制Wnt/β-catenin信号通路活性,从而抑制乳腺癌细胞的增殖和转移能力。     

LncRNA OIP5-AS1调节miR-25-3p/SOX4轴对高糖诱导的人肾小管上皮细胞生物学过程的影响

目的 探讨长链非编码RNA Opa相互作用蛋白5-反义转录物1(lncRNA OIP5-AS1)对高糖诱导的人肾小管上皮细胞增殖、凋亡和氧化应激损伤的影响及分子机制。方法 体外培养人肾皮质近曲小管上皮细胞HK-2,分为正常葡萄糖组（NG组）、高糖组（HG组）、HG+si-NC组、HG+si-OIP5-AS1组、HG+miR-NC组、HG+miR-25-3p组、HG+si-OIP5-AS1+inhibitor-NC组、HG+si-OIP5-AS1+miR-25-3p inhibitor组。转染48 h后,实时荧光定量PCR(qPCR)检测细胞中lncRNA OIP5-AS1、miR-25-3p和性别决定区Y框蛋白4(SOX4)m RNA水平;CCK-8法检测细胞活力;检测细胞培养上清液中乳酸脱氢酶（LDH）活性;流式细胞术分析细胞凋亡情况;检测细胞中丙二醛（MDA）水平和超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性;DCFH-DA荧光探针检测细胞内活性氧（ROS）的产生;Western blot实验检测细胞中SOX4、B细胞淋巴瘤因子2(Bcl-2)、Bcl-2相关X蛋白（Bax）...     

4-Hydroxynonenal enhances MMP-9 production in murine macrophages via 5-lipoxygenase-mediated activation of ERK and p38 MAPK

Exaggerated levels of 4-hydroxynonenal (HNE) and 5-lipoxygenase (5-LO) co-exist in macrophages in atherosclerotic lesions, and activated macrophages produce MMP-9 that degrades atherosclerotic plaque constituents. This study investigated the effects of HNE on MMP-9 production, and the potential role for 5-LO derivatives in MMP-9 production in murine macrophages. Stimulation of J774A.1 cells with HNE led to activation of 5-LO, as measured by leukotriene B₄ (LTB₄) production. This was associated with an increased production of MMP-9, which was blunted by inhibition of 5-LO with MK886, a 5-LO inhibitor or with 5-LO siRNA. A cysteinyl-LT₁ (cysLT₁) receptor antagonist, REV-5901 as well as a BLT₁ receptor antagonist, U-75302, also attenuated MMP-9 production induced by HNE. Furthermore, LTB₄ and cysLT (LTC₄ and LTD₄) enhanced MMP-9 production in macrophages, suggesting a pivotal role for 5-LO in HNE-mediated production of MMP-9. Among the MAPK pathways, LTB₄ and cysLT enhanced phosphorylation of ERK and p38 MAPK, but not JNK. Linked to these results, a p38 MAPK inhibitor as well as an ERK inhibitor blunted MMP-9 production induced by LT. Collectively, these data suggest that 5-LO-derived LT mediates HNE-induced MMP-9 production via activation of ERK and p38 MAPK pathways, consequently leading to plaque instability in atherosclerosis.     

Eupatilin, a dietary flavonoid, induces G2/M cell cycle arrest in human endometrial cancer cells

This study is the first to investigate the antiproliferative effect of eupatilin in human endometrial cancer cells. Eupatilin, a naturally occurring flavonoid isolated from Artemisia princeps, has anti-inflammatory, anti-oxidative, and anti-tumor activities. In the present study, we investigated the potential effect of eupatilin on cell growth and its molecular mechanism of action in human endometrial cancer cells. Eupatilin was more potent than cisplatin in inhibiting cell viability in the human endometrial cancer cell lines Hec1A and KLE. Eupatilin showed relatively low cytotoxicity in normal human endometrial cells HES and HESC cells when compared to cisplatin. Eupatilin induced G2/M phase cell cycle arrest in a time- and dose-dependent manner, as indicated by flow cytometry analysis. In addition, treatment of Hec1A cells with eupatilin resulted in a significant increase in the expression of p21^WAF1/CIP1 and in the phosphorylation of Cdc25C and Cdc2. Knockdown of p21 using specific siRNAs significantly compromised eupatilin-induced cell growth inhibition. Interestingly, levels of mutant p53 in Hec1A cells decreased markedly upon treatment with eupatilin, and p53 siRNA significantly increased p21 expression. Moreover, eupatilin modulated the phosphorylation of protein kinases ERK1/2, Akt, ATM, and Chk2. These results suggest that eupatilin inhibits the growth of human endometrial cancer cells via G2/M phase cell cycle arrest through the up-regulation of p21 by the inhibition of mutant p53 and the activation of the ATM/Chk2/Cdc25C/Cdc2 checkpoint pathway.     

2,3′,4,4′,5′-Pentamethoxy-trans-stilbene, a resveratrol derivative, is a potent inducer of apoptosis in colon cancer cells via targeting microtubules

Resveratrol, a naturally occurring polyphenolic antioxidant, is a compound holding promise for cancer chemoprevention. Previous studies suggest that 2,3′,4,5′-tetramethoxy-trans-stilbene (TMS) and 3,4,4′,5,-tetramethoxy-trans-stilbene (MR-4), both of which are derivatives of resveratrol, are potent apoptosis-inducing agents with clinical potential. In this study, we chemically synthesized 2,3′,4,4′,5′-pentamethoxy-trans-stilbene (PMS), the hybrid molecule of TMS and MR-4, and determined its effects on colon cancer growth. When compared with its parent compounds, PMS displayed more potent in vitro anti-mitogenic effect on colon cancer cells (Caco-2, HT-29 and SW1116). Moreover, PMS inhibited tumor growth in vivo in a colon cancer xenograft model. In this connection, PMS strongly induced apoptosis in HT-29 cells as evidenced by increased PARP cleavage, DNA fragmentation, and accumulation of sub-G₁ population. Further mechanistic analysis revealed that PMS enhanced the polymerization of microtubules, which was followed by G₂/M mitotic arrest and caspase-dependent apoptosis. The activation of caspases-3, -7, -8, and -9 was involved in PMS-induced apoptosis with concomitant down-regulation of the pro-survival PI3K/Akt signaling. Collectively, these data suggest that PMS is a potent inducer of apoptosis via targeting microtubules and may merit investigation as a potential chemoprophylactic and therapeutic agent for colon cancer.     

丹酚酸A激活AKT/mTOR/4EBP1通路缓解脂多糖诱导的H9c2心肌细胞凋亡和氧化应激

目的探究丹酚酸A(Sal A)对脂多糖(LPS)诱导的氧化应激性损伤H9c2心肌细胞增殖、凋亡,以及蛋白激酶B(AKT)/哺乳动物雷帕霉素靶蛋白(mTOR)/起始因子4E结合蛋白(4EBP1)通路相关蛋白表达的影响。方法用LPS诱导制备H9c2心肌细胞氧化应激性损伤模型,分别用含Sal A 5,10和20 mg·L^-1的DMEM培养基培养细胞24 h,加LPS 1 mg·L^-1继续孵育24 h。用5-乙炔基-2’脱氧尿嘧啶核苷(EdU)染色观察H9c2心肌细胞存活;采用流式细胞术检测H9c2心肌细胞凋亡和线粒体膜电位;用试剂盒检测细胞培养液中乳酸脱氢酶(LDH)和超氧化物歧化酶(SOD)活性及丙二醛(MDA)和谷胱甘肽(GSH)含量;Western印迹法检测胱天蛋白酶3、胱天蛋白酶9、存活蛋白、Bax/Bcl-2,AKT、磷酸化AKT(p-AKT)、mTOR、p-mTOR、4EBP1和p-4EBP1蛋白表达水平。结果与细胞对照组比较,模型组EdU红色标记的细胞减少(P<0.05);与模型组比较,Sal A 5,10和20 mg·L^-1处理组EdU红色标记的细胞增多(P<0.05)。Sal A能降低培养液中LDH活性及细胞内MDA和GSH含量,增加胞内SOD活性(P<0.05),减少心肌细胞的凋亡率(P<0.05),降低心肌细胞线粒体膜电位的下降速度(P<0.05)。Sal A 10和20 mg·L^-1处理后,活化胱天蛋白酶3、活化胱天蛋白酶9和Bax/Bcl-2蛋白水平显著下调(P<0.05),存活蛋白水平显著上调(P<0.05);与细胞对照组比较,模型组AKT/mTOR/4EBP1磷酸化水平均显著降低(P<0.05)。与模型组比较,Sal A 10和20 mg·L^-1组AKT和mTOR磷酸化水平均显著升高(P<0.05)。结论Sal A通过激活AKT/mTOR/4EBP1通路、减少心肌细胞凋亡并降低心肌细胞线粒体膜电位的下降速度,减缓了LPS诱导的H9c2心肌细胞凋亡和氧化应激,表明Sal A对LPS造成的氧化应激损伤心肌细胞具有保护作用。