Apoptosis In Human Breast Cancer Research Articles

MiRNA-183-5p promotes cell proliferation and inhibits apoptosis in human breast cancer by targeting the PDCD4

MicroRNAs are often aberrantly expressed in breast cancer and postulated to play a causal role in the onset and maintenance of breast cancer by binding to its target mRNA. Here, we evaluated the effects of miRNA-183-5p on cell proliferation and apoptosis which attempted to elucidate the potential role of miR-183-5p/PDCD4 axis in human breast cancer. We found that the miR-183-5p expression level was extremely promoted in breast cancer in comparison with the adjacent normal tissues. Overexpression of miR-183-5p significantly enhanced the cell proliferation and inhibited cell apoptosis in MCF-7 and MDA-MB-231 cells. Moreover, PDCD4 was predicted as a putative target of miR-183-5p by bioinformatic approaches, and miR-183-5p negatively regulated the expression of PDCD4. Furthermore, knockdown of PDCD4 suppressed expression of p21 and p27, which was consistent with the result of the attachment of miR-183-5p. These data collectively demonstrate that miR-183-5p exerts oncomiRs effects in breast cancer, and may have broad impacts on the field of using antimiRs as anti-cancer drugs for breast cancer.

Curcumin inhibits intracellular fatty acid synthase and induces apoptosis in human breast cancer MDA-MB-231 cells.

High levels of fatty acid synthase (FAS) expression have been found in many tumors, including prostate, breast, and ovarian cancers, and inhibition of FAS has been reported to obstruct tumor growth in vitro and in vivo. Curcumin is one of the major active ingredients of Curcuma longa, which has been proven to inhibit the growth of cancer cells. In the present study, we investigated the potential activity of curcumin as a FAS inhibitor for chemoprevention of breast cancer. As a result, curcumin induced human breast cancer MDA-MB-231 cell apoptosis with the half-inhibitory concentration value of 3.63 ± 0.26 µg/ml, and blocked FAS activity, expression and mRNA level in a dose-dependent manner. Curcumin also regulated B-cell lymphoma 2 (Bcl-2), Bax and p-Akt protein expression in MDA-MB-231 cells. Moreover, FAS knockdown showed similar effect as curcumin. All these results suggested that curcumin may induce cell apoptosis via inhibiting FAS.

Amplexicaule A exerts anti-tumor effects by inducing apoptosis in human breast cancer.

Chemotherapy is the main treatment for patients with breast cancer metastases, but natural alternatives have been receiving attention for their potential as novel anti-tumor reagents. Amplexicaule A (APA) is a flavonoid glucoside isolated from rhizomes of Polygonum amplexicaule D. Don var. sinense Forb (PADF). We found that APA has anti-tumor effects in a breast cancer xenograft mouse model and induces apoptosis in breast cancer cell lines. APA increased levels of cleaved caspase-3,-8,-9 and PARP, which resulted from suppression of MCL-1 and BCL-2 expression in the cells. APA also inactivated the Akt/mTOR pathway in breast cancer cells. Thus, APA exerts a strong anti-tumor effect on breast cancer cells, most likely through induction of apoptosis. Our study is the first to identify this novel anti-tumor compound and provides a new strategy for isolation and separation of single compounds from herbs.

Induction of Apoptosis in Human Cancer Cells with Extracts of Taraxacum coreanum, Youngia sonchifolia and Ixeris dentate

This research examined the effects of Compositae extract on the inhibition of proliferation and apoptosis in human breast and human gastric cancer cells. Compositae extracts which is used in the experiment are Taraxacum coreanum (TC), Youngia sonchifolia (YS) and Ixeris dentata (ID). The proliferation of SK-BR-3, MDA- MB-231 and AGS cells were investigated by MTT assay. ID and YS extracts inhibited proliferation of SK-BR-3, MDA-MB-231 and AGS cells in a dose-dependent manner, but TC have barely affected. In addition, the most effec- tive extract was ID. To assess the apoptosis of ID extract, the nuclei of human cancer cells were stained with DAPI solution respectively. Chromatin condensation, indicated apoptosis, was increased in a dose-dependent manner. We investigated change of ID extract-induced apoptosis proteins on human cancer cells by western blot analysis. The level of Bcl-2 decreased, whereas the level of Bax, cleaved-PARP increased in dose-dependent manner compared with non-treatment. Also Bax/Bcl-2 ratio, which is used in clinical indicator of apoptosis, was increased at ID extract treat- ment group compared with non-treatment. Moreover the Bax/Bcl-2 ratio of MDA-MB-231 cell was significantly increased as against SK-BR-3, AGS cells. These results indicated that ID extract have anti-proliferation effect better than YS or TC, and induced apoptosis in human breast cancer MDA-MB-231 cell better than human breast cancer SK- BR-3 cell, human gastric cancer. Even if further research is needed, ID can be developed as a chemopreventive or therapeutic agent of breast cancer.

Effect of poly(ADP-ribose)polymerase inhibitor combined with carbo on apoptosis of human breast cancer cells

To investigate the effect of poly(ADP-ribose)polymerase(PARP)inhibitor ABT888 combined with carbo on apoptosis of human breast cancer cells. MTT was used to detect the cell viability of MDA-MB-435s cells after treatment of carbo and ABT888 with different concentration. FACS and Western-blotting were used to detect the cell apoptosis rate and apoptosis-related protein expression, respectively. Combined application of carbo and ABT888 significantly inhibited the proliferation of MDA-MB-435s cells, and the inhibition rates were significantly higher than that of carbo or ABT888 alone. The combination of carbo and ABT888 markedly induced cell apoptosis(26.3%±1.5%) more than carbo(18.6%±1.6%, P<0.01) and ABT888(14.7%±2.3%, P<0.01) alone. Combination of carbo and ABT888 significantly down-regulated the expression of anti-apoptosis factors Bcl-2 and up-regulated the pro-apoptosis proteins Bax and cleaved caspase-3. The combination of carbo and ABT888 can suppress the proliferation and induce apoptosis of human breast cancer DA-MB-435s cells.

MiRNA-24-3p promotes cell proliferation and inhibits apoptosis in human breast cancer by targeting p27Kip1.

MicroRNAs (miRNAs) are often aberrantly expressed in breast cancer and are postulated to play a role in its initiation and progression. In the present study, we found that the expression level of miR-24-3p was upregulated in breast cancer in comparison with the level in adjacent normal tissues. Overexpression of miR-24-3p was able to promote cell proliferation and inhibit cell apoptosis in MDA-MB-435 and MDA-MB-468 cells. With the bioinformatic method, we further identified that p27Kip1 is a direct target of miR-24-3p, and its protein level was negatively regulated by miR-24-3p. Therefore, the data reported here demonstrate that miR-24-3p is an important regulator in breast cancer, and imply that the miR-24-3p/p27Kip1 axis has potential as a therapeutic target for breast cancer.

27-O-(E)-p-coumaric acyl ursolic acid via JNK/SAPK signal pathway regulates apoptosis of human breast cancer MDA-MB-231 cell line

27-O-(E)-p-coumaric acyl ursolic acid( DY-17) from Ilex latifolia is a compound of the monomer. To investigate the DY-17 inducing apoptosis in the human breast cancer cell line, the MDA-MB-231 cells were used as research object in this experiment. The proliferation activity of the MDA-MB-231 cells stimulated with the different concentrations of DY-17 (20, 40 µmol · L(-1)) was detected at different time( 12, 24, 36, 48, 60,72 h) . We surveyed the DY-17 inducing apoptosis of the MDA-MB-231 cells with the fluorescent staining technology. The rate of MDA-MB-231 cells apoptosis and necrosis was determined by flow cell cytometry (FCC). Moreover, expression of JNK, phosphorylated JNK, Bax, PARP shear and caspase-3 shear related to JNK/SAPK pathways were investigated in every group ( control group, EGF group, EGF + DY-17 40 µmol · L(1) group and EGF + SP600125 group) with Western blot. The MTT results showed that, in the presence of DY-17, the proliferation activity of MDA-MB-231 cells decreased in a dose-dependent and time-dependent manner. The apoptosis and necrosis rates of MDA-MB-231 cells with DY-17(20, 40 µmol · L(-1)) groups was respectively 31.86%, 49.91% by flow cytometry and significantly increased compared with control group under Fluores- cence microscopy. Up-regulation of the JNK phosphorylation protein expression was observed in EGF group compared with control group. In addition, markedly decreased the expression of JNK phosphorylation protein were also surveyed in EGF + DY-17 40 µmol · L(-1) group compared with EGF group. The expression of Bax, shear PARP and shear caspase-3 protein in EGF + DY-17 40 µmol · L(-1) group were significantly increased in comparison with EGF group. The results showed DY-17 induced apoptosis of human breast cancer MDA-MB-231 cell line related to down-regulating JNK/SAPK signal pathways.

The high-mobility group nucleosome-binding domain 5 is highly expressed in breast cancer and promotes the proliferation and invasion of breast cancer cells.

The high-mobility group nucleosome-binding domain 5 (HMGN5) is a member of the high-mobility group proteins family. Previous study found that HMGN5 is required for tumorigenesis in vitro, and aberrations in the expression of HMGN5 were found in human osteosarcoma, prostate cancer, and squamous cell carcinoma. Nevertheless, the role of HMGN5 in breast cancer remains unclear. This study aimed to investigate the expression and clinical significance of HMGN5 in human breast cancer, confirm the oncogenic role of HMGN5, and explore the mechanism by which HMGN5 contributes to invasion and metastasis. HMGN5 expression was detected in breast cancer tissues and corresponding adjacent non-cancerous tissues from 43 patients by immunohistochemistry, and the clinicopathologic characteristics of all patients were also analyzed. Next, knockdown of HMGN5 protein in MDA-MB-231 cells was performed through a small interfering RNA (siRNA) technique, and cell viability, apoptosis, and invasion were detected by cell vitality test, flow cytometry, and transwell assay, respectively. Immunohistostaining showed that HMGN5 were highly expressed in the nucleus in all breast cancer tissues as compared with the adjacent non-cancerous tissues (ANCT;(73.5 ± 11 vs. 31.0 ± 5 %, P < 0.01). HMGN5 expression level was associated with the poorly differentiated tumor cells, lymph node involvement tumor, and T4 staging tumor. Knockdown of HMGN5 inhibited cell growth, suppressed invasion, and increased cell apoptosis in human breast cancer MDA-MB-231 cells. Western blot analysis demonstrated that the expressions of PCNA, connective tissue growth factor (CTGF), and MMP-9 were decreased in human breast MDA-MB-231 cells depleted of HMGN5. In addition, the apoptotic markers (cleaved PARP and cleaved caspase-3) were significantly increased by HMGN5 knockdown, but microtubule-associated protein 1 light chain 3-II/I (LC3-II/I) did not alter. HMGN5 plays an oncogenic role in human breast cancer by inhibiting cell proliferation and invasion, and activating apoptosis, which could be exploited as a target for therapy in human breast cancer.

Effects and mechanism of downregulation of COX‑2 expression by RNA interference on proliferation and apoptosis of human breast cancer MCF‑7 cells.

The aim of the present study was to investigate the effects of RNA interference with prostaglandin-endoperoxide synthase 2 (COX‑2) gene on the proliferation and apoptosis of breast cancer MCF‑7 cells, as well as the underlying mechanism. The present study constructed the eukaryotic expression vector of the targeted COX‑2 gene, transfected the MCF‑7 cells and screened the stably expressed clone. Changes in the COX‑2 gene expression in breast cancer MCF‑7 cells prior to and following transfection were examined; the proliferation and apoptosis of MCF‑7 cells were analyzed. Furthermore, changes in the protein levels of survivin, B-cell lymphoma 2 (Bcl‑2) and Bcl-2-associated X (Bax) genes were detected. RNA interference mediated by a lentiviral expression vector significantly decreased the protein expression levels of the COX‑2 gene, and therefore, the proliferation and growth of breast cancer MCF‑7 cells was significantly suppressed and the apoptotic rate increased. Of note, the mRNA and protein expression levels of survivin and Bcl‑2 decreased, while those of Bax increased following COX-2 silencing. RNA interference markedly deactivated the COX‑2 gene, suppressed the proliferation of breast cancer MCF‑7 cells, and, to a certain extent, enhanced the induced spontaneous apoptosis, which is regulated by the Bax gene. These results provided evidence for the potential applications of RNA interference of the targeted COX‑2 gene in gene therapy for the treatment of breast cancer.

MicroRNA-874 inhibits cell proliferation and induces apoptosis in human breast cancer by targeting CDK9

It has been demonstrated that miR-874 plays important roles in many types of cancers. Nevertheless, its biological function in breast cancer remains largely unknown. In this study, we found that the expression level of miR-874 is down-regulated in breast cancer in comparison with the adjacent normal tissues. The overexpression of miR-874 is able to inhibit cell proliferation and induce cell apoptosis and cell cycle arrest in MCF7 and MDA-MB-231 cells. Using a bioinformatics method, we further show that CDK9 is a direct target of miR-874 and that its protein level is negatively regulated by miR-874. Therefore, the data reported in this manuscript demonstrate that miR-874 is an important regulator in breast cancer and imply that the miR-874/CDK9 axis has potential as a therapeutic target for breast cancer.

Inactivated Sendai virus strain Tianjin induces apoptosis in human breast cancer MDA-MB-231 cells.

Sendai virus strain Tianjin is a novel genotype. Here, we investigate the antitumor and proapoptotic effects of ultraviolet-inactivated Sendai virus strain Tianjin (UV-Tianjin) on human breast cancer MDA-MB-231 cells in vitro, as well as the involvement of the apoptotic pathway in the mechanism of UV-Tianjin-induced antitumor effects. MTT assays showed that treatment with UV-Tianjin dose-dependently inhibited the proliferation of MDA- MB-231 cells but not normal MCF 10A breast epithelium cells. Hoechst staining and flow cytometric analysis revealed that UV-Tianjin induced apoptosis of MDA-MB-231 cells in a dose-dependent manner. Moreover, UV-Tianjin treatment resulted in reduction in the mitochondria membrane potential (MMP) and release of cytochrome complex (cyt c) via regulation of Bax and Bcl-2, as well as activation of caspase-9, caspase-3, Fas, FasL and caspase-8 in MDA-MB-231 cells. In summary, our study suggests that UV-Tianjin exhibits anticancer activity in human breast cancer MDA-MB-231 cells through inducing apoptosis, which may involve both the endogenous mitochondrial and exogenous death receptor pathways.

Wasabi-Derived 6-(Methylsulfinyl)Hexyl Isothiocyanate Induces Apoptosis in Human Breast Cancer by Possible Involvement of the NF-κB Pathways

6-(methylsulfinyl)hexyl isothiocyanate (6-MSITC) is a bioactive ingredient of wasabi (Wasabia japonica), which is a popular spice in Japan. 6-MSITC has been reported to inhibit the proliferation of breast cancer and melanoma cell lines. We inoculated 30 female Balb-nu/nu mice with MDA-MB-231 or -453 cells, and orally administered varying concentrations of 6-MSITC for 12 days following tumor growth. The tumor volumes and tumor weights from mice inoculated with MDA-MB-231 cells, and the tumor volumes of MDA-MB-453 cells were significantly inhibited by 6-MSITC on Days 9 and 11 after drug administration. DNA fragmentation, DNA ladder, and caspase 3/7 activity performed in vitro revealed that 6-MSITC induced apoptosis of MDA-MB-231, MDA-MB-453, and MCF-7 cells. Furthermore, nuclear factor-κB (NF-κB) expression in the nuclei and phosphorylation of inhibitor κBα (IκBα) was downregulated by 6-MSITC in a concentration-dependent manner; however, this activity was not observed in MCF-7 cells. Moreover, this downregulation of phosphorylated IκBα by 6-MSITC in MDA-MB-231 and -453 cells supports its inhibitory effects on NF-κB activity. The expression of phosphorylated AKT (pAKT) reduced by 6-MSITC was confirmed in MDA-MB-231 cells. Thus, we conclude that 6-MITC promotes apoptosis of breast cancer cells by inhibiting NF-kB and therefore releasing its control of the PI3K/AKT pathway.

Luteolin enhances paclitaxel-induced apoptosis in human breast cancer MDA-MB-231 cells by blocking STAT3

The potential use of low-dose chemotherapy has been appealing because lower dosages are more attainable during cancer therapy and cause less toxicity in patients. Combination therapy of paclitaxel, a promising frontline chemotherapy agent, with natural anti-tumor agents that are considerably less toxic and possess the capability of activating additional apoptotic signals may provide a rational molecular basis for novel chemotherapeutic strategies. Luteolin, a natural flavone, possesses multiple biological activities, including anti-tumor potential. In the present study, the effects of concomitant administration of luteolin and paclitaxel were investigated in human breast cancer MDA-MB-231 cells. Luteolin alone demonstrated an anti-proliferative effect. Co-administration of luteolin and paclitaxel resulted in an increase in apoptosis compared with the treatment of paclitaxel alone as evidenced by the results of a diamidino-2-phenylindole (DAPI) stain and Annexin-V-based assay. Moreover, immunoblotting analysis also showed that the co-administration of luteolin and paclitaxel activated caspase-8 and caspase-3 and increased the expression of Fas. Furthermore, the increased expression of Fas due to co-administration was shown to be due to the blocking of signal transducer and activator of transcription 3 (STAT3). Finally, combination therapy with luteolin and paclitaxel significantly reduced tumor size and tumor weight in an orthotopic tumor model of MDA-MB-231 cells in nude mice. These results suggest that the luteolin–paclitaxel combination could be a novel strategy for the treatment of breast cancer.

Targeting beta-Catenin signaling to induce apoptosis in human breast cancer cells by z-Guggulsterone and Gugulipid extract of Ayurvedic medicine plant Commiphora mukul

Backgroundz-Guggulsterone (z-Gug) and Gugulipid (GL) have been used to treat a variety of ailments. We now report their anti-cancer effect and mechanism against human breast cancer.MethodsUsing the human estrogen receptor-positive (MCF-7) and triple-negative (MDA-MB-231) breast cancer cells as well as the normal human mammary epithelial cell line (HMEC), we evaluated the anti-breast-cancer efficacy and apoptosis inducing activity of GL. We determined the cellular and molecular mechanism of GL-inhibited breast cancer cell growth.ResultsGL significantly inhibited growth of MCF-7 and MDA-MB-231 cells with an IC50~2 μM at pharmacologically relevant concentrations standardized to its major active constituent z-Gug. The GL-induced growth inhibition correlated with apoptosis induction as evidenced by an increase in cytoplasmic histone-associated DNA fragmentation and caspase 3 activity. The GL-induced apoptosis was associated with down-regulation of the β-Catenin signaling pathway. The decreased expression of Wnt/β-Catenin targeting genes, such as cyclin D1, C-myc and survivin, and the inhibition of the activity of the transcription factor (T-cell factor 4, TCF-4) were observed in GL-treated breast cancer cells. The GL treatment resulted in a significant reduction of β-Catenin /TCF-4 complex in both of the cancer cells. The GL-induced apoptotic cell death was significantly enhanced by RNA Interference of β-Catenin and TCF-4. On the other hand, the normal human mammary epithelial cell HMEC, compared with the human breast cancer cells, is significantly more resistant to growth inhibition and apoptosis induction by GL.ConclusionThe present study indicates that the β-Catenin signaling pathway is the target for GL-induced growth inhibition and apoptosis in human breast cancer.

Ginsenoside Rg3 Induces Apoptosis of Human Breast Cancer (MDA-MB-231) Cells.

Background:Rg3, a major ginsenoside derived from heat-processed ginseng, has been reported to have anti-inflammatory and anti-proliferative activities. In our previous studies, Rg3 inhibited phorbol ester-induced cyclooxygenase-2 expression and NF-κB activation in cultured human mammary epithelial (MCF-10A) cells and in mouse skin in vivo. In this study, we investigated Rg3-induced apoptosis in human breast cancer (MDA-MB-231) cells and underlying molecular mechanisms.Methods:After Rg3 treatment, apoptotic cell death of MDA-MB-231 cell was investigated by the MTT reduction assay and measurement of the mitochondrial membrane depolarization. Flow cytometry was used for cell cycle analysis and detection of apoptotic cells as well as measurement of reactive oxygen species. Expression of apoptotic-related proteins was determined by immunoblot analysis.Results:MDA-MB-231 cells treated with Rg3 (30μM) exhibited the increased proportion of hypodiploid or apoptotic cells. Rg3 treatment resulted in an increase in the ratio of proapoptotic Bax to antiapoptotic Bcl-2, depolarization of the mitochondria membrane potential and the release of cytochrome c from mitochondria. Rg3 also induced the proteolytic cleavage of caspase-3 and poly (ADP-ribose) polymerase, which was attenuated by a caspase-3 inhibitor, z-VAD-fmk.Conclusions:Based on these findings, it is likely that Rg3 induces apoptosis in MDA-MB-231 cells via classical mitochondria-dependent caspase activation. These data suggest that Rg3 might be a potential candidate as a breast cancer chemopreventive agent.

Co-treatment with Quercetin and 1,2,3,4,6-Penta-O-galloyl-β-d-glucose Causes Cell Cycle Arrest and Apoptosis in Human Breast Cancer MDA-MB-231 and AU565 Cells

Breast cancer is the most universal cancer in women, but the medications for breast cancer usually cause serious side effects and offer no effective treatment for triple-negative breast cancer. Here, we investigated the growth inhibitory effects of gallic acid (GA), (-)-epigallocatechin gallate (EGCG), or 1,2,3,4,6-penta-O-galloyl-β-D-glucose (5GG) combined with quercetin (Que) on breast cancer cells. In this study, we tested the combined effects of these compounds on estrogen receptor (ER)/human epidermal growth factor 2 (Her2)-negative (MDA-MB-231), ER-positive/Her2-negative (BT483), and ER-negative/Her2-positive (AU565) breast cancer cells. After treatment of each cell line with these compounds, we found that Que combined with 5GG induced S-phase arrest and apoptosis in MDA-BM-231 cells through downregulation of S-phase kinase protein 2 expression, but induced G2/M-phase arrest and apoptosis in AU565 cells through downregulation of Her2 expression. Additionally, Que combined with 5GG was more effective in inhibiting MDA-MB-231 cell growth than Que combined with EGCG (5GG analogue) or GA. The combination of 5GG and Que can offer great potential for the chemoprevention of ER-negative breast cancer.

Combined treatment with verrucarin A and tumor necrosis factor-α sensitizes apoptosis by overexpression of nuclear factor-kappaB-mediated Fas

Verrucarin A (VA) is a member of the family of macrocyclic trichothecenes, which exhibit anti-cancer and immune-modulating activities. However, VA has not yet been demonstrated to be involved in the sensitization of tumor necrosis factor-alpha (TNF-α)-mediated apoptosis. In the present study, we found that VA triggers TNF-α-induced apoptosis in human breast cancer MDA-MB-231 and MCF-7 cells. In particular, activation of caspas-3 and caspase-8 as well as release of cytochrome c were significantly enhanced in response to the combined treatment with VA and TNF-α (VA/TNF-α) and the pan-caspase inhibitor z-VAD-fmk completely reversed the apoptosis, suggesting that caspases are the main effector molecules in VA/TNF-α-induced apoptosis via the intrinsic and extrinsic pathway. Moreover, we confirmed that enhanced Fas expression plays a critical role, because the Fas-blocking antibody partially inhibited VA/TNF-α-induced apoptosis. VA also increased specific DNA-binding activity of nuclear factor-kappaB (NF-κB) via nuclear translocation of p50 and p65. In addition, pretreatment with the NF-κB inhibitor MG132 blocked VA/TNF-α-induced apoptosis by suppression of NF-κB-dependent Fas expression. These results indicated that VA enhances TNF-α-induced apoptosis via NF-κB-dependent Fas overexpression.

TRIM16 overexpression induces apoptosis through activation of caspase-2 in cancer cells

TRIM16 exhibits tumour suppressor functions by interacting with cytoplasmic vimentin and nuclear E2F1 proteins in neuroblastoma and squamous cell carcinoma cells, reducing cell migration and replication. Reduced TRIM16 expression in a range of human primary malignant tissues correlates with increased malignant potential. TRIM16 also induces apoptosis in breast and lung cancer cells, by unknown mechanisms. Here we show that overexpression of TRIM16 induces apoptosis in human breast cancer (MCF7) and neuroblastoma (BE(2)-C) cells, but not in non-malignant HEK293 cells. TRIM16 increased procaspase-2 protein levels in MCF7 and induced caspase-2 activity in both MCF7 and BE(2)-C cells. We show that TRIM16 and caspase-2 proteins directly interact in both MCF7 and BE(2)-C cells and co-localise in MCF7 cells. Most importantly, the induction of caspase-2 activity is required for TRIM16 to initiate apoptosis. Our data suggest a novel mechanism by which TRIM16 can promote apoptosis by directly modulating caspase-2 activity.

Estrogen Receptor Beta-Mediated Proliferative Inhibition and Apoptosis in Human Breast Cancer by Calycosin and Formononetin

Background: Calycosin and formononetin are two main components of isoflavones. In our previous studies, we have respectively reported their antitumor activities on breast cancer cell MCF-7. To further investigate the feasibility of isoflavones in clinically treating breast carcinoma, here we specifically focused on the comparison between calycosin and formononetin, along with the relevant mechanism. Methods: ER-positive (MCF-7, T-47D) and ER-negative breast cancer cells (MDA-231, MDA-435) were respectively treated with calycosin or formononetin. Cell proliferation and apoptosis were measured by MTT assay and flow cytometry. mRNA levels of ER beta (ERβ) and miR-375 were quantifed by real-time PCR. Expression of ERβ and insulin-like growth factor 1 receptor (IGF-1R), and activation of poly (ADP-ribose) polymerase 1 (PARP-1) were determined by Western blotting. Results: Both calycosin and formononetin impaired proliferation and triggered apoptosis of ER-positive breast cancer cells (MCF-7, T-47D) in a time- and dose-dependent manner, especially in the treatment with calycosin. However, no such effect was observed in ER-negative breast cancer cells, indicating the correlation between isoflavones-induced inhibitory effect and ERs. Thus calycosin and most sensitive MCF-7 cells were used to study the relevant signaling pathway. After the treatment of calycosin, ERβ expression was significantly increased in MCF-7 cells, followed by decrease of IGF-1R, activation of PARP-1 cleavage and downregulation of miR-375. Conclusion: Calycosin has an advantage on inhibiting breast cancer growth in comparison with formononetin, which is obtained by ERβ-mediated regulation of IGF-1R signaling pathways and miR-375 expression.

Involvement of the mitochondrial pathway and Bim/Bcl-2 balance in dihydroartemisinin-induced apoptosis in human breast cancer in vitro

Dihydroartemisinin (DHA), a semi-synthetic derivative and active metabolite of artemisinin, has been shown to have profound anticancer potential in addition to its strong anti-malarial activity. The purpose of the present study was to thoroughly investigate the anti-neoplastic effects induced by DHA and to provide a molecular basis for the use of DHA in the treatment of breast cancer. Our results demonstrated that DHA could significantly inhibit the cell proliferation of breast cancer in a dose- and time-dependent manner that was associated with induced apoptosis and G0/G1 cell cycle arrest, and the half maximal inhibitory concentrations (IC50) of DHA treatment were 60.03, 33.86 and 17.18µM for 24, 48 and 72h, respectively. Moreover, the DHA treatment dramatically increased the protein expression of caspase-8, cleaved caspase-9, activated Bid and induced the release of cytochromec from mitochondria into the cytosol. In addition, the apoptotic action of DHA was associated with the increased expression of the pro-apoptotic gene Bim and a decreased expression of the anti-apoptotic gene Bcl-2. Therefore, the mitochondrial pathway is involved in the apoptosis of breast cancer cells induced by DHA and the imbalance of the Bim/Bcl-2 interaction may promote the beneficial effect against breast cancer cells. Overall, our study provides the scientific rationale for the clinical usage of DHA for breast cancer.