The natural antioxidant alpha-lipoic acid induces p27-dependent cell cycle arrest and apoptosis in MCF-7 human breast cancer cells

Unlike normal cells, tumor cells survive in a specific redox environment where the elevated reactive oxygen species contribute to enhance cell proliferation and to suppress apoptosis. Alpha-lipoic acid, a naturally occurring reactive oxygen species scavenger, has been shown to possess anticancer activity, due to its ability to suppress proliferation and to induce apoptosis in different cancer cell lines. Since at the moment little information is available regarding the potential effects of alpha-lipoic acid on breast cancer, in the present study we addressed the question whether alpha-lipoic acid induces cell cycle arrest and apoptosis in the human breast cancer cell line MCF-7. Moreover, we investigated some molecular mechanisms which mediate alpha-lipoic acid actions, focusing on the role of the PI3-K/Akt signalling pathway. We observed that alpha-lipoic acid is able to scavenge reactive oxygen species in MCF-7 cells and that the reduction of reactive oxygen species is followed by cell growth arrest in the G1 phase of the cell cycle, via the specific inhibition of Akt pathway and the up-regulation of the cyclin-dependent kinase inhibitor p27^kip1, and by apoptosis, via changes of the ratio of the apoptotic-related protein Bax/Bcl-2. Thus, the anti-tumor activity of alpha-lipoic acid observed in MCF-7 cells further stresses the role of redox state in regulating cancer initiation and progression.     

Triptolide inhibits human breast cancer MCF-7 cell growth via downregulation of the ERα-mediated signaling pathway

Aim:

To investigate the anticancer mechanisms of triptolide, a diterpenoid isolated from the plant Tripterygium wilfordii Hook F, against human breast cancer cells and the involvement of the estrogen receptor-α (ERα)-mediated signaling pathway in particular.

Methods:

Human breast cancer ERα-positive MCF-7 cells and ERα-negative MDA-MB-231 cells were tested. PrestoBlue assay was used to evaluate the cell viability. The levels of ERα mRNA and protein were detected with real-time PCR and immunoblotting, respectively. Mouse models of MCF-7 or MDA-MB-231 xenograft tumors were treated with triptolide (0.4 mg·kg⁻¹·d⁻¹, po) or a selective estrogen receptor modulator tamoxifen (mg·kg⁻¹·d⁻¹, po) for 3 weeks, and the tumor weight and volume were measured.

Results:

Triptolide (5–200 nmol/L) dose-dependently inhibited the viability of both MCF-7 and MDA-MB-231 cells, with a more potent inhibition on MCF-7 cells. Knockdown of ERα in MCF-7 cells by siRNA significantly attenuated the cytotoxicity of triptolide, whereas overexpression of ERα in MDA-MB-231 cells markedly enhanced the cytotoxicity. Triptolide dose-dependently decreased the expression of ERα in MCF-7 cells and MCF-7 xenograft tumors. Furthermore, treatment of MCF-7 cells with triptolide inhibited the phosphorylation of ERK1/2 in dose- and time-dependent manners. In the mice xenografted with MCF-7 cells, treatment with triptolide or tamoxifen resulted in significant reduction in the tumor weight and volume. Similar effects were not obtained in the mice xenografted with MDA-MB-231 cells.

Conclusion:

The anticancer activity of triptolide against ERα-positive human breast cancer is partially mediated by downregulation of the ERα-mediated signaling pathway.     

Parasporin A13-2 of Bacillus thuringiensis Isolates from the Papaloapan Region (Mexico) Induce a Cytotoxic Effect by Late Apoptosis against Breast Cancer Cells

The protein A13-2 was obtained from Bacillus thuringiensis strains isolated from the Papaloapan watershed region (Oaxaca, Mexico). The cytotoxic activity of parasporal inclusions was studied against breast cancer cell line (MCF-7) and normal cell (human peripheral blood mononuclear cells). The MTT, the formation of reactive species, nitric oxide, free cell DNA, and the type of death cellular were assessed. The protein A13-2 shows the highest cytotoxic activity against MCF-7 (13% cell viability at 6 µg/mL), the extracellular DNA increases, and it shows no stress for reactive species or nitric oxide. Besides, the A13-2 parasporin shows no toxicity to peripheral blood mononuclear cells, and it does not generate changes in nitric oxide levels or free cell DNA. Due to that, the cytotoxic effect of A13-2 was specific for MCF-7, and it does not affect normal cells. According to microscopy and flow cytometry, A13-2 parasporin leads to the death of MCF-7 cells by late apoptosis together with necrosis and without allowing the triggering of the survival mechanisms. When analyzed together, our results show for the first time that the A13-2 protein isolated from Mexican strains of B. thuringiensis preferentially kills MCF- 7 (cancer cells) over HEK 293 and PBMC cell lines (normal cells), thus representing a promising alternative for the treatment of cancer breast.     

Synergistic induction of apoptosis by combination treatment with mesupron and auranofin in human breast cancer cells

Urokinase-type plasminogen activator (uPA) has been validated as a predictive or prognostic biomarker protein, and mesupron is considered the first-in-class anticancer agent to inhibit uPA activity in human breast cancer. In the present study, we showed that the synergism between mesupron and auranofin, a thioredoxin reductase inhibitor, for inducing of apoptosis in MCF-7 human breast cancer cells. Our results demonstrated that mesupron and auranofin significantly lead to inhibition of the cancer cells proliferation; cell cycle arrest at the G1/S phase of the cell cycle, and apoptosis as indicated by caspase 3 activation, poly(ADP-ribose) polymerase cleavage, and annexin V staining. Isobologram analyses of MCF-7 cells showed a clear synergism between mesupron and auranofin. This combined treatment decreased the levels of mitochondrial anti-apoptotic factors, such as BCL-2, BCL-xL, and MCL-1 and caused nuclear translocation of apoptosis-inducing factor. Mitochondrial membrane potential (Δψ _m ) was found to be strongly disrupted in combination-treated cells. In addition, combination treatment significantly enhanced the overproduction of reactive oxygen species, which was rescued by N-acetylcysteine treatment. The combination treatment suppressed phosphorylation of Akt, thus contributing to apoptosis. Taken together, our data suggest that the use of mesupron in combination with auranofin may be important in achieving high anticancer synergy.     

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.     

四氢异喹啉类新化合物SYT-1抑制肿瘤细胞增殖的机制

探讨四氢异喹啉类新化合物SYT-1对肿瘤细胞增殖抑制作用及其机制.采用CCK-8(cell counting kit-8)法检测细胞增殖;克隆形成实验检测细胞克隆形成能力;JC-1探针法检测细胞线粒体膜电位;DCFH-DA(2',7'-dichlorodihydrofluorescein diacetate)探针法检测...     

1-oxoeudesm-11(13)-ene-12,8α-lactone-induced apoptosis via ROS generation and mitochondria activation in MCF-7 cells

A novel eudesmane-type sesquiterpene compound, 1-oxoeudesm-11(13)-eno-12,8a-lactone (OEL), was isolated from Aster himalaicus. Its effect on apoptosis in human breast adenocarcinoma (MCF-7) cells was investigated. MTT assay showed that OEL substantially reduced the viability of KB, MCF-7, U87, A172, and MG-63 cells. MCF-7 cells were used to further evaluate the antitumor effects and anticancer mechanisms of OEL. OEL-induced apoptosis was characterized by chromatin condensation, formation of apoptotic bodies, and phosphatidylserine on extracellular surface; these effects were confirmed by DAPI nuclear staining and flow cytometry. Increased expression of Bax and deceased expression of Bcl-2 were also observed in OELtreated MCF-7 cells. Moreover, OEL induced the loss of mitochondria membrane potential, release of cytochrome C, activation of caspase-9, and generation of reactive oxygen species. These findings indicate that reactive oxygen species generation and mitochondria activation were involved in apoptosis induced by OEL in MCF-7 cells. The results from our study demonstrated that OEL may be a promising pro-apoptotic compound that could be used to develop novel anticancer drugs.     

Evaluation of the cytotoxicity,cell-cycle arrest,and apoptotic induction by Euphorbia hirta in MCF-7 breast cancer cells

Context: Euphorbia hirta L. (Euphorbiaceae) has been used as a folk remedy in Southeast Asia for the treatment of various ailments.

Objective: The current study evaluates the cytotoxicity, cell-cycle arrest, and apoptotic induction by E. hirta in MCF-7 breast cancer cells.

Materials and methods: Cytotoxic activity of methanol extract of whole part of E. hirta was determined by the MTT assay at various concentrations ranging from 1.96 to 250.00?µg/mL in MCF-7 cells. Cell morphology was assessed by light and fluorescence microscopy. Apoptosis and cell-cycle distribution were determined by annexin V staining and flow cytometry. DNA fragmentation, caspase activity, and reactive oxygen species (ROS) assays were performed using the commercially available kits. To identify the cytotoxic fraction, E. hirta extract was subjected to bioassay-guided fractionation.

Results: Euphorbia hirta exhibited significant inhibition of the survival of MCF-7 cells and the half inhibitory concentration (IC₅₀) values was 25.26?µg/mL at 24?h. Microscopic studies showed that E. hirta-treated cells exhibited marked morphological features characteristic of apoptosis. Euphorbia hirta extract also had an ignorable influence on the LDH leakage and generating intracellular ROS. The flow cytometry study confirmed that E. hirta extract induced apoptosis in MCF-7 cells. Euphorbia hirta also resulted in DNA fragmentation in MCF-7 cells. Moreover, E. hirta treatment resulted in the accumulation of cells at the S and G₂/M phases as well as apoptosis. The caspase activity study revealed that E. hirta extract induced apoptosis through the caspase-3-independent pathway by the activation of caspase-2, 6, 8, and 9. Euphorbia hirta hexane fraction, namely HFsub4 fraction, demonstrated highest activity among all the fractions tested with an IC₅₀ value of 10.01?µg/mL at 24?h.

Discussion and conclusion: This study revealed that E. hirta induced apoptotic cell death and suggests that E. hirta could be used as an apoptosis-inducing anticancer agent for breast cancer treatment with further detailed studies.     

DT389-YP7, a Recombinant Immunotoxin against Glypican-3 That Inhibits Hepatocellular Cancer Cells: An In Vitro Study

Hepatocellular carcinoma (HCC) is one of the high-metastatic types of cancer, and metastasis occurs in one-third of patients with HCC. To maintain the effectiveness of drug compounds on cancer cells and minimize their side effects on normal cells, it is important to use new approaches for overcoming malignancies. Immunotoxins (ITs), an example of such a new approach, are protein-structured compounds consisting of toxic and binding moieties which can specifically bind to cancer cells and efficiently induce cell death. Here, we design and scrutinize a novel immunotoxin against an oncofetal marker on HCC cells. We applied a truncated diphtheria toxin (DT389) without binding domain as a toxin moiety to be fused with a humanized YP7 scFv against a high-expressed Glypican-3 (GPC3) antigen on the surface of HCC cells. Cytotoxic effects of this IT were investigated on HepG2 (GPC3⁺) and SkBr3 (GPC3⁻) cell lines as positive- and negative-expressed GPC3 antigens. The dissociation constant (Kd) was calculated 11.39 nM and 18.02 nM for IT and YP7 scfv, respectively, whereas only IT showed toxic effects on the HepG2 cell line, and decreased cell viability (IC50 = 848.2 ng/mL). Changing morphology (up to 85%), cell cycle arrest at G2 phase (up to 13%), increasing intracellular reactive oxygen species (ROSs) (up to 50%), inducing apoptosis (up to 38% for apoptosis and 23% for necrosis), and an almost complete inhibition of cell movement were other effects of immunotoxin treatment on HepG2 cells, not on SkBr3 cell line. These promising results reveal that this new recombinant immunotoxin can be considered as an option as an HCC inhibitor. However, more extensive studies are needed to accomplish this concept.     

Amelioration of influenza virus-induced reactive oxygen species formation by epigallocatechin gallate derived from green tea

Aim:

To study whether epigallocatechin gallate (EGCG), a green tea-derived polyphenol, exerted anti-influenza A virus activity in vitro and in vivo.

Methods:

Madin-Darby canine kidney (MDCK) cells were tested. The antiviral activity of EGCG in the cells was determined using hemagglutination assay and qPCR. Time of addition assay was performed to determine the kinetics of inhibition of influenza A by EGCG. The level of reactive oxygen species (ROS) were determined with confocal microscopy and flow cytometry. BALB/c mice were treated with EGCG (10, 20 or 40 mg·kg⁻¹·d⁻¹, po) for 5 d. On the 3rd d of the treatment, the mice were infected with influenza A virus. Histopathological changes, lung index and virus titers in the lungs were determined.

Results:

Treatment of influenza A-infected MDCK cells with EGCG (1.25–100 nmol/L) inhibited influenza A replication in a concentration-dependent manner (the ED₅₀ value was 8.71±1.11 nmol/L). Treatment with EGCG (20 nmol/L) significantly suppressed the increased ROS level in MDCK cells following influenza A infection. In BALB/c mice infected with influenza virus, oral administration of EGCG (40 mg·kg⁻¹·d⁻¹) dramatically improved the survival rate, decreased the mean virus yields and mitigated viral pneumonia in the lungs, which was equivalent to oral administration of oseltamivir (40 mg·kg⁻¹·d⁻¹), a positive control drug.

Conclusion:

The results provide a molecular basis for development of EGCG as a novel and safe chemopreventive agent for influenza A infection.     

Isoalantolactone induces apoptosis in human breast cancer cells via ROS-mediated mitochondrial pathway and downregulation of SIRT1

Isoalantolactone possessed various biological activities. However, whether it could treat breast cancer and its underlying mechanism remained largely unknown. This study was designed to evaluate the anticancer effects of isoalantolactone on breast cancer and explored the molecular mechanism. Two human breast cancer cell lines (MDA-MB-231 and MCF-7) and one normal breast cell line (MCF-10A) were applied. Our data suggested that isoalantolactone decreased breast cancer cell viability in a dose-dependent manner, but showed almost no toxicity to MCF-10A cells. The anticancer effects of isoalantolactone were related to the overexpression of reactive oxygen species. Isoalantolactone significantly induced breast cancer cell apoptosis by activating caspase cascade, cleaving poly (ADP-ribose) polymerase. Increase of Bax/Bcl-2 ratio, depolarization of mitochondrial membrane potential, release of cytochrome c from mitochondria to cytoplasm and cell cycle arrest at G2/M phase were associated to the apoptosis induction. Additionally, isoalantolactone increased the protein expression of p38 MAPK and JNK. The apoptosis-induction of isoalantolactone could be abrogated by co-treatment with SB203580 (inhibitor of p38 MAPK) or SP600125 (inhibitor of JNK). Furthermore, isoalantolactone induced breast cancer cells apoptosis in a caspase-independent pathway, which was downregulation of SIRT1. Therefore, isoalantolactone may serve as a chemotherapeutic agent for the treatment of human breast cancer.     

Characterization of the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound,in vitro and in vivo

Aim:

To investigate the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound in vitro and in vivo.

Methods:

The anti-proliferative action of S115 was analyzed in 12 human and mouse cancer cell lines using MTT assay. Autograft and xenograft cancer models were made by subcutaneous inoculation of cancer cells into mice or nude mice. The mice were orally treated with S115 (2, 8, 32 mg·kg⁻¹·d⁻¹) for 7 d, and the tumor size was measured every 3 d. Cell apoptosis and cell cycle distribution were examined using flow cytometry, gene expression profile analyses, Western blots and RT-PCR.

Results:

The IC₅₀ values of S115 against 12 human and mouse cancer cell lines ranged from 0.3 to 6.6 μmol/L. The tumor growth inhibition rate caused by oral administration of S115 (32 mg·kg⁻¹·d⁻¹) were 89.7%, 81.7%, 78.4% and 77.8%, respectively, in mouse model of B16 melanoma, mouse model of Colon26 colon cancer, nude mouse model of A549 lung cancer and nude mouse model of SK-OV-3 ovarian cancer. Furthermore, oral administration of S115 (7.5 mg·kg⁻¹·d⁻¹) synergistically enhanced the anticancer effects of cyclophosphamide, cisplatin, or 5-fluorouracil in mouse model of S180 sarcoma. Treatment of A549 human lung cancer cells with S115 (1.5 μmol/L) induced G₀/G₁ cell cycle arrest, and increased apoptosis. Furthermore, S115 downregulated the level of ubiquitin, and upregulated the level of Tob2 in A549 cells.

Conclusion:

S115 exerts anticancer effects against a variety of cancer cells in vitro and in grafted cancer models by inducing apoptosis, downregulating ubiquitin and upregulating Tob2.     

Growth factors and chemotherapeutic modulation of breast cancer cells

A variety of molecules including growth factors are involved in the metastasis of breast cancer cells to bone. We have investigated the effects of osteoblast derived growth factors, such as insulin-like growth factor-1 (IGF-1) and transforming growth factor beta-1 (TGF-beta1), on doxorubicin (adriamycin)-induced apoptosis and growth arrest of estrogen receptor positive (ER+) (MCF-7) and negative (ER-) (MDA-MB-435) breast cancer cell lines. Human breast normal epithelial (MCF-10A), breast cancer (MCF-7) and metastatic breast cancer (MDA-MB-435) cell lines were exposed to different doses of doxorubicin (0.1, 1 or 10 microM) at various exposure times (12, 24 or 48 h). The doxorubicin cytotoxicity was found to be higher in cancer cell lines (MDA-MB-435 and MCF-7) compared with normal breast epithelial cells (MCF-10A cells). Doxorubicin appeared to exert a blockade of MCF-7 and MDA-MB-435 cells at the G2/M phase, and induced apoptosis in MDA-MB-435 (29 +/- 4.2% vs 3.4 +/- 1.9% control) as assessed by flow cytometry, DNA fragmentation and terminal deoxynucleotidyl-transferase mediated deoxyuridine 5-triphosphate and biotin nick-end labelling (TUNEL) assays. Estradiol (E2) stimulated the growth of MCF-7 cells and increased the distribution of the cells at the G2/M and S phases. Exogenous IGF-1 partially neutralized the doxorubicin cytotoxicity in both cancer cell lines (MCF-7 and MDA-MB-435). Similarly, TGF-beta1 partially neutralized the doxorubicin cytotoxicity in MDA-MB-435 cells by reducing the number of cells at the 相似文献   

Different apoptotic effects of saxifragifolin C in human breast cancer cells

Breast cancer is currently the most common form of cancer affecting women. Recent studies have reported that triterpenoid saponins isolated from Androsace umbellata exhibit anti-proliferative effects in several types of cancer cells. However, the cytotoxic effect of saxifragifolin C (Saxi C) on breast cancer cells remains unclear. The purpose of this study is to evaluate the in vitro anti-tumor activity of Saxi C in human breast cancer cells. Our data indicated that MDA-MB-231 cells were more sensitive than MCF-7 cells to Saxi C treatment. In addition, Saxi C inhibited cell survival through the induction of reactive oxygen species and the caspase-dependent pathway in the MDA-MB-231 cells, whereas MCF-7 cells treated with Saxi C underwent the apoptotic cell death in a caspase-independent manner. Although Saxi C treatment resulted in the induction of activation of MAPKs in both types of human breast cancer cells, p38 MAPK and JNK, but not ERK1/2, appeared to be involved in Saxi C-induced apoptosis. Moreover, ERα-overexpressing MDA-MB-231 cells remained alive, whereas the survival of shERα-transfected MCF-7 cells decreased. Taken together, Saxi C induced apoptosis in MCF-7 cells and MDA-MB-231 cells via different regulatory mechanisms, and ERα status might be essential for regulating Saxi C-induced apoptosis in breast cancer cells. Thus, Saxi C is a potential chemotherapeutic agent in breast cancer.     

Ginseng saponin metabolite induces apoptosis in MCF-7 breast cancer cells through the modulation of AMP-activated protein kinase

Previous studies have shown that the ginseng saponin metabolite, Compound K (20-O-d-glucopyranosyl-20(S)-protopanaxadiol, IH901), suppresses proliferation of various cancers and induces apoptosis. AMP-activated protein kinase (AMPK) is a sensor of cellular energy states and is involved in apoptosis of cancer cells. We hypothesized that Compound K may exert cytotoxicity in MCF-7 human breast cancer cells through modulation of AMPK, followed by a decrease in cyclooxygenase-2 (COX-2) expression. Compound K inhibited cell growth, induced apoptosis via generation of reactive oxygen species (ROS), as well as decreasing COX-2 expression and prostaglandin E(2) (PGE(2)) levels. These effects of Compound K were induced via an AMPK-dependent pathway and were abrogated by a specific AMPK inhibitor. These results suggest that Compound K induced apoptosis by modulating AMPK-COX-2 signaling in MCF-7 human breast cancer cells.     

Cytotoxicity,cell cycle arrest,and apoptosis in breast cancer cell lines exposed to an extract of the seed kernel of Mangifera pajang (bambangan)

An extract of Mangifera pajang kernel has been previously found to contain a high content of antioxidant phytochemicals. The present research was conducted to investigate the anticancer potential of this kernel extract. The results showed that the kernel crude extract induced cytotoxicity in MCF-7 (hormone-dependent breast cancer) cells and MDA-MB-231 (non-hormone dependent breast cancer) cells with IC50 values of 23 and 30.5 μg/ml, respectively. The kernel extract induced cell cycle arrest in MCF-7 cells at the sub-G1 (apoptosis) phase of the cell cycle in a time-dependent manner. For MDA-MB-231 cells, the kernel extract induced strong G2-M arrest in cell cycle progression at 24 h, resulting in substantial sub-G1 (apoptosis) arrest after 48 and 72 h of incubation. Staining with Annexin V-FITC and propidium iodide revealed that this apoptosis occurred early in both cell types, 36 h for MCF-7 cells and 24 h for MDA-MB-231cells, with 14.0% and 16.5% of the cells respectively undergoing apoptosis at these times. This apoptosis appeared to be dependent on caspase-2 and -3 in MCF-7 cells, and on caspase-2, -3 and -9 in MDA-MB-231 cells. These findings suggest that M. pajang kernel extract has potential as a potent cytotoxic agent against breast cancer cell lines.     

Antitumor activities of quercetin and quercetin-5′,8-disulfonate in human colon and breast cancer cell lines

This study is designed to compare the anticancer effects of quercetin and its water-soluble sulfated derivative, quercetin-5′,8-disulfonate (QS), in human colon cancer LoVo cells and breast cancer MCF-7 cells. It was found that both quercetin and QS can inhibit the growth of cancer cells in a dose-dependent manner, with the IC₅₀ values of 40.2 and 28.0 μM for LoVo cells and 30.8 and 19.9 μM for MCF-7 cells, respectively, suggesting QS was more effective against the cancer cells than quercetin. Moreover, flow cytometric assay revealed that quercetin and QS could mediate the cell-cycle arrest principally in the S phase after 24 h of treatment with the two tumor cells. It was also found that 69.6% of LoVo cells and 90.6% of MCF-7 cells entered the early phase of apoptosis when treated with 100 μM QS for 48 h. Furthermore, we firstly found the generation of ROS is a critical mediator in QS-induced cell growth inhibition. Taken together, the novel sulfated derivative of quercetin possesses strong antitumor activity via a ROS-dependent apoptosis pathway, and has the excellent potential to be developed into an antitumor precursor compound.     

Bornyl caffeate induces apoptosis in human breast cancer cells in vitro via the ROS- and JNK-mediated pathways

Aim： To investigate the effects of bornyl caffeate discovered in several species of plant on human breast cancer cells in vitro and the underlying mechanisms.
Methods： Human breast cancer cell line MCF-7 and other tumor cell lines （T47D, HepG2, HeLa, and PC12） were tested. Cell viability was determined using MTT assay, and apoptosis was defined by monitoring the morphology of the nuclei and staining with Annexin V-FITC. Mitochondrial membrane potential （MMP） was measured using JC-1 under fluorescence microscopy. Intracellular reactive oxygen species （ROS） were assessed by flow cytometry. The expression of apoptosis-associated proteins was determined by Western blotting analysis.

Results： Bornyl caffeate （10, 25, and 50 μmol/L） suppressed the viability of MCF-7 cells in dose- and time-dependent manners, but neither caffeic acid nor borneol showed cytotoxicity at a concentration of 50 μmol/L. Bornyl caffeate also exerted cytotoxicity to HepG2, Hela, T47D, and PC12 cells. Bornyl caffeate dose-dependently induced apoptosis of MCF-7 cells, increased the expression of Bax and decreased the expression of Bcl-xl, resulting in the disruption of MMP and subsequent activation of caspase-3. Moreover, bornyl caffeate triggered the formation of ROS and activated p38 and c-Jun JNK. In MCF-7 cells, the cytotoxicity of bornyl caffeate was significantly attenuated by SB203580 （p38 inhibitor）, SP600125 （JNK inhibitor）, z-VAD （pan-caspase inhibitor） or the thiol antioxidant L-NAC.

Conclusion： Bornyl caffeate exerts non-selective cytotoxicity against cancer cells of different origin in vitro. The compound induces apoptosis in human breast cancer MCF-7 cells via the ROS- and JNK-mediated pathways.     

人参皂甙Rg3对乳腺癌MCF-7线粒体凋亡途径的影响

目的探讨20(R)–人参皂甙Rg3(SPG-Rg3)对人乳腺癌MCF-7细胞的诱导凋亡作用及其可能机制。方法人乳腺癌细胞MCF-7细胞株分为空白对照组、实验对照组及SPG-Rg3多个浓度组。利用MTT法观察人参皂甙Rg3对MCF-7细胞生长的抑制作用,并计算出IC-50,进一步确定其有效浓度;流式细胞术检测人参皂甙Rg3作用后MCF-7细胞周期的变化;利用AnnexinV-EGFP/PI双染法,检测人参皂甙Rg3诱导MCF-7细胞凋亡情况;免疫细胞化学染色检测MCF-7细胞凋亡与Fas、FasL蛋白表达的关系。结果 SPG-Rg3作用48h的IC-50为244.54μg/mL。流式细胞仪检测Rg3使MCF-7的S期细胞比率明显增加(P<0.01),凋亡率明显增加(P<0.01)。免疫细胞化学显示Rg3能使MCF-7细胞胞浆内细胞色素C增加(P<0.01)。结论 SPG-Rg3能诱导乳腺癌MCF-7细胞凋亡,其机制可能与诱导线粒体释放细胞色素C有关。