Flavonoids identified from Korean Scutellaria baicalensis induce apoptosis by ROS generation and caspase activation on human fibrosarcoma cells

Iridin Induces G2/M Phase Cell Cycle Arrest and Extrinsic Apoptotic Cell Death through PI3K/AKT Signaling Pathway in AGS Gastric Cancer Cells

Iridin is a natural flavonoid found in Belamcanda chinensis documented for its broad spectrum of biological activities like antioxidant, antitumor, and antiproliferative effects. In the present study, we have investigated the antitumor potential of iridin in AGS gastric cancer cells. Iridin treatment decreases AGS cell growth and promotes G2/M phase cell cycle arrest by attenuating the expression of Cdc25C, CDK1, and Cyclin B1 proteins. Iridin-treatment also triggered apoptotic cell death in AGS cells, which was verified by cleaved Caspase-3 (Cl- Caspase-3) and poly ADP-ribose polymerase (PARP) protein expression. Further apoptotic cell death was confirmed by increased apoptotic cell death fraction shown in allophycocyanin (APC)/Annexin V and propidium iodide staining. Iridin also increased the expression of extrinsic apoptotic pathway proteins like Fas, FasL, and cleaved Caspase-8 in AGS cells. On the contrary, iridin-treated AGS cells did not show variations in proteins related to an intrinsic apoptotic pathway such as Bax and Bcl-xL. Besides, Iridin showed inhibition of PI3K/AKT signaling pathways by downregulation of (p-PI3K, p-AKT) proteins in AGS cells. In conclusion, these data suggest that iridin has anticancer potential by inhibiting PI3K/AKT pathway. It could be a basis for further drug design in gastric cancer treatment.

PRDX6 Overexpression Promotes Proliferation, Invasion, and Migration of A549 Cells in vitro and in vivo

Purpose

Peroxiredoxin-6 (PRDX6) is frequently found in various cancers. However, its expression and relevance to proliferation, invasion, and migration in human non-small-cell lung cancer (NSCLC) remain unclear. This study investigated the role and novel mechanism of PRDX6 in progression in an NSCLC cell line (A549).

Methods

We analyzed the expression of PRDX6 in NSCLC and adjacent normal tissues and explored the proliferation, migration, and invasion of A549 cells using either a PRDX6 plasmid or PRDX6 small interfering RNA (siRNA). We also assessed the effects of PRDX6 on the epithelial–mesenchymal transition (EMT) and β-catenin-mediated transcription of target genes.

Results

PRDX6 expression was markedly higher in NSCLC tissues than in adjacent tissues. Proliferation, invasion, and migration of A549 cells were promoted by overexpression of PRDX6 but inhibited by its silencing. PRDX6 overexpression inhibited the protein expression of both phosphorylated β-catenin and E-cadherin, as well as the expression of vimentin, TWIST, and downstream targets of β-catenin including c-MYC, TCF-4, and MMP14. Conversely, PRDX6 silencing markedly decreased the expression of c-MYC, TCF-4, and MMP14, and inhibited EMT in A549 cells. Overexpression of PRDX6 in vivo notably increased the volume and weight of tumors.

Conclusion

PRDX6 overexpression promotes the proliferation, invasion, and migration of A549 cells in vitro and in vivo.

Anticancer Activities of Thymus vulgaris L. in Experimental Breast Carcinoma in Vivo and in Vitro

Naturally-occurring mixtures of phytochemicals present in plant foods are proposed to possess tumor-suppressive activities. In this work, we aimed to evaluate the antitumor effects of Thymus vulgaris L. in in vivo and in vitro mammary carcinoma models. Dried T. vulgaris (as haulm) was continuously administered at two concentrations of 0.1% and 1% in the diet in a chemically-induced rat mammary carcinomas model and a syngeneic 4T1 mouse model. After autopsy, histopathological and molecular analyses of rodent mammary carcinomas were performed. In addition, in vitro evaluations using MCF-7 and MDA-MB-231 cells were carried out. In mice, T. vulgaris at both doses reduced the volume of 4T1 tumors by 85% (0.1%) and 84% (1%) compared to the control, respectively. Moreover, treated tumors showed a substantial decrease in necrosis/tumor area ratio and mitotic activity index. In the rat model, T. vulgaris (1%) decreased the tumor frequency by 53% compared to the control. Analysis of the mechanisms of anticancer action included well-described and validated diagnostic and prognostic markers that are used in both clinical approach and preclinical research. In this regard, the analyses of treated rat carcinoma cells showed a CD44 and ALDH1A1 expression decrease and Bax expression increase. Malondialdehyde (MDA) levels and VEGFR-2 expression were decreased in rat carcinomas in both the T. vulgaris treated groups. Regarding the evaluations of epigenetic changes in rat tumors, we found a decrease in the lysine methylation status of H3K4me3 in both treated groups (H3K9m3, H4K20m3, and H4K16ac were not changed); up-regulations of miR22, miR34a, and miR210 expressions (only at higher doses); and significant reductions in the methylation status of four gene promoters—ATM serin/threonine kinase, also known as the NPAT gene (ATM); Ras-association domain family 1, isoform A (RASSF1); phosphatase and tensin homolog (PTEN); and tissue inhibitor of metalloproteinase-3 (TIMP3) (the paired-like homeodomain transcription factor (PITX2) promoter was not changed). In vitro study revealed the antiproliferative and proapoptotic effects of essential oils of T. vulgaris in MCF-7 and MDA-MB-231 cells (analyses of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS); 5-bromo-20-deoxyuridine (BrdU); cell cycle; annexin V/PI; caspase-3/7; Bcl-2; PARP; and mitochondrial membrane potential). T. vulgaris L. demonstrated significant chemopreventive and therapeutic activities against experimental breast carcinoma.

Dietary phytochemicals in breast cancer research: anticancer effects and potential utility for effective chemoprevention

Cancerous tissue transformation developing usually over years or even decades of life is a highly complex process involving strong stressors damaging DNA, chronic inflammation, comprehensive interaction between relevant molecular pathways, and cellular cross-talk within the neighboring tissues. Only the minor part of all cancer cases are caused by inborn predisposition; the absolute majority carry a sporadic character based on modifiable risk factors which play a central role in cancer prevention. Amongst most promising candidates for dietary supplements are bioactive phytochemicals demonstrating strong anticancer effects. Abundant evidence has been collected for beneficial effects of flavonoids, carotenoids, phenolic acids, and organosulfur compounds affecting a number of cancer-related pathways. Phytochemicals may positively affect processes of cell signaling, cell cycle regulation, oxidative stress response, and inflammation. They can modulate non-coding RNAs, upregulate tumor suppressive miRNAs, and downregulate oncogenic miRNAs that synergically inhibits cancer cell growth and cancer stem cell self-renewal. Potential clinical utility of the phytochemicals is discussed providing examples for chemoprevention against and therapy for human breast cancer. Expert recommendations are provided in the context of preventive medicine.

Selective Cytotoxicity of Luteolin and Kaempferol on Cancerous Hepatocytes Obtained from Rat Model of Hepatocellular Carcinoma: Involvement of ROS-Mediated Mitochondrial Targeting

To evaluate the cytotoxicity effects of luteolin (LUT) and kaempferol (KAE) via reactive oxygen species (ROS) mediated mitochondrial targeting on hepatocytes obtained from the liver of hepatocellular carcinoma (HCC) rats. In this study, HCC induced by diethylnitrosamine (DEN) and 2-acetylaminofluorene (2-AAF). In the following, rat liver hepatocytes and mitochondria were isolated and tested for every eventual apoptotic and anti-HCC effects of LUT and KAE. The results of MTT assay showed that LUT and KAE were able to induce selective cytotoxicity in hepatocytes of HCC group in a dose- and time-dependent manner. Treatment of mitochondria from hepatocytes of HCC group with LUT and KAE were accompanied by loss of mitochondrial membrane potential (MMP) and mitochondrial swelling and release of cytochrome c (P < 0.001) via reactive oxygen species (ROS) generation before cytotoxicity ensued. LUT and KAE also increased activation of caspase-3 (P < 0.001 and P < 0.01, respectively). Flow-cytometry analysis indicated that the mode of cell death induced by these flavonoids were mostly apoptosis. Importantly, LUT and KAE were nontoxic for healthy hepatocytes and mitochondria. Therefore, we suggest that LUT and KAE are a good candidate for the complementary therapeutic agent against HCC.

Dietary flavonoids, luteolin and quercetin, inhibit invasion of cervical cancer by reduction of UBE2S through epithelial-mesenchymal transition signaling

We previously reported that the dietary flavonoids, luteolin and quercetin, might inhibit the invasiveness of cervical cancer by reversing epithelial-mesenchymal transition (EMT) signaling. However, the regulatory mechanism exerted by luteolin and quercetin is still unclear. This study analyzed the invasiveness activation by ubiquitin E2S ligase (UBE2S) through EMT signaling and inhibition by luteolin and quercetin. We found that UBE2S expression was significantly higher in highly invasive A431 subgroup III (A431-III) than A431-parental (A431-P) cells. UBE2S small interfering (si)RNA knockdown and overexpression experiments showed that UBE2S increased the migratory and invasive abilities of cancer cells through EMT signaling. Luteolin and quercetin significantly inhibited UBE2S expression. UBE2S showed a negative correlation with von Hippel-Lindau (VHL) and a positive correlation with hypoxia-induced factor (Hif)-1α. Our findings suggest that high UBE2S in malignant cancers contributes to cell motility through EMT signaling and is reversed by luteolin and quercetin. UBE2S might contribute to Hif-1α signaling in cervical cancer. These results show the metastatic inhibition of cervical cancer by luteolin and quercetin through reducing UBE2S expression, and provide a functional role for UBE2S in the motility of cervical cancer. UBE2S could be a potential therapeutic target in cervical cancer.

Antineoplastic effects of clove buds (Syzygium aromaticum L.) in the model of breast carcinoma

It is supposed that plant functional foods, rich in phytochemicals, may potentially have preventive effects in carcinogenesis. In this study, the anticancer effects of cloves in the in vivo and in vitro mammary carcinoma model were assessed. Dried flower buds of cloves (CLOs) were used at two concentrations of 0.1% and 1% through diet during 13 weeks after the application of chemocarcinogen. After autopsy, histopathological and immunohistochemical analyses of rat mammary carcinomas were performed. Moreover, in vitro evaluation using MCF‐7 cells was carried out. Dietary administered CLO caused the dose‐dependent decrease in tumour frequency by 47.5% and 58.5% when compared to control. Analysis of carcinoma cells in animals showed bcl‐2, Ki67, VEGFA, CD24 and CD44 expression decrease and Bax, caspase‐3 and ALDH1 expression increase after high‐dose CLO administration. MDA levels were substantially decreased in rat carcinomas in both CLO groups. The evaluation of histone modifications revealed increase in lysine trimethylations and acetylations (H4K20me3, H4K16ac) in carcinomas after CLO administration. TIMP3 promoter methylation levels of CpG3, CpG4, CpG5 islands were altered in treated cancer cells. An increase in total RASSF1A promoter methylation (three CpG sites) in CLO 1 group was found. In vitro studies showed antiproliferative and pro‐apoptotic effects of CLO extract in MCF‐7 cells (analyses of cytotoxicity, Brdu, cell cycle, annexin V/PI, caspase‐7, Bcl‐2 and mitochondrial membrane potential). This study showed a significant anticancer effect of clove buds in the mammary carcinoma model in vivo and in vitro.

An untargeted metabolomics approach to determine component differences and variation in their in vivo distribution between Kuqin and Ziqin, two commercial specifications of Scutellaria Radix

Kuqin (KQ) and Ziqin (ZQ), derived from the roots of Scutellaria baicalensis Georgi, are two important commercial specifications of Scutellariae Radix (SR, termed Huang qin in Chinese).

Young Barley Indicates Antitumor Effects in Experimental Breast Cancer In Vivo and In Vitro

The effect of dietary administered young barley containing a mixture of phytochemicals to female rats for the prevention of N-methyl-N-nitrosourea-induced mammary carcinogenesis was evaluated. After carcinogen administration (14 wk), mammary tumors were removed and prepared for histopathological and immunohistochemical analysis. Moreover, in vitro evaluation of possible mechanisms in MCF-7 breast cancer cell line was performed. Barley (0.3%) demonstrated mild antitumor effect in mammary carcinogenesis, yet 3% barley did not further improve this effect. Immunohistochemical analysis of rat tumor cells in treated groups showed significant increase in caspase-3 expression and significant reduction in Ki67 expression. In addition, 3% barley significantly decreased dityrosine levels versus control. Barley in higher dose significantly decreased serum low-density lipoprotein-cholesterol in rats. In vitro studies showed that barley significantly decreased survival of MCF-7 cells in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and significantly decreased 5-bromo-20-deoxyuridine incorporation versus control. Barley prevented cell cycle progression and extended incubation with barley showed significant increase in the percentage of annexin V/propidium iodide-positive MCF-7 cells. Our results propose an antitumor effect for the mixture of phytochemicals present in young barley in a breast cancer model.

Oregano demonstrates distinct tumour-suppressive effects in the breast carcinoma model

PURPOSE

There has been a considerable interest in the identification of natural plant foods for developing effective agents against cancer. Thus, the anti-tumour effects of oregano in the in vivo and in vitro breast cancer model were evaluated.

METHODS

Lyophilized oregano (ORE) was administered at two concentrations of 0.3 and 3 % through diet. The experiment was terminated 14 weeks after carcinogen administration. At autopsy, mammary tumours were removed and prepared for histopathological and immunohistochemical analysis. Moreover, in vitro evaluation in MCF-7 cells was carried out.

RESULTS

Low-dose ORE suppressed tumour frequency by 55.5 %, tumour incidence by 44 %, and tumour volume by 44.5 % compared to control animals. Analysis of rat tumour cells showed Ki67, VEGFR-2, CD24, and EpCAM expression decrease and caspase-3 expression increase after low-dose ORE treatment. High-dose ORE lengthened tumour latency by 12.5 days; moreover, Bcl-2, VEGFR-2, CD24, and EpCAM expression decrease and caspase-3 expression increase in carcinoma cells were observed. Histopathological analysis revealed a decrease in the ratio of high-/low-grade carcinomas in both treated groups. In vitro studies showed that ORE decreased survival and proliferation of MCF-7 cells. In ORE-treated MCF-7 cells, an increase in cells expressing sub-G ₀/G ₁ DNA content and an increase in the percentage of annexin V/PI positive MCF-7 cells were observed. In vitro, both caspase-dependent and possible non-caspase-dependent apoptotic pathways were found. The deactivation of anti-apoptotic activity of Bcl-2, a decrease in mitochondrial membrane potential, and the activation of mitochondrial apoptosis pathway were observed in the ORE-treated MCF-7 cells.

CONCLUSIONS

Our results demonstrate, for the first time, a distinct tumour-suppressive effect of oregano in the breast cancer model.

Colon cancer chemopreventive effects of baicalein, an active enteric microbiome metabolite from baicalin

Baicalin is a major constituent of Scutellaria baicalensis, which is a commonly used herbal medicine in many Asian countries. After oral ingestion, intestinal microbiota metabolism may change parent compound's structure and its biological activities. However, whether baicalin can be metabolized by enteric microbiota and the related anticancer activity is not clear. In this study, using human enteric microbiome incubation and HPLC analysis, we observed that baicalin can be quickly converted to baicalein. We compared the antiproliferative effects of baicalin and baicalein using a panel of human cancer cell lines, including three human colorectal cancer (CRC) cell lines. In vitro antiproliferative effects on CRC cells were verified using an in vivo xenograft nude mouse model. Baicalin showed limited antiproliferative effects on some of these cancer cell lines. Baicalein, however, showed significant antiproliferative effects in all the tested cancer cell lines, especially on HCT-116 human colorectal cancer cells. In vivo antitumor results supported our in vitro data. We demonstrated that baicalein exerts potent S phase cell cycle arrest and pro-apoptotic effects in HCT-116 cells. Baicalein induced the activation of caspase 3 and 9. The in silico modeling suggested that baicalein forms hydrogen bonds with residues Ser251 and Asp253 at the active site of caspase 3, while interactions with residues Leu227 and Asp228 in caspase 9 through its hydroxyl groups. Data from this study suggested that baicalein is a potent anticancer metabolite derived from S. baicalensis. Enteric microbiota play a key role in the colon cancer chemoprevention of S. baicalensis.

Fruit peel polyphenols demonstrate substantial anti-tumour effects in the model of breast cancer

PURPOSE

Fruit and vegetable intake is inversely correlated with cancer; thus, it is proposed that an extract of phytochemicals as present in whole fruits, vegetables, or grains may have anti-carcinogenic properties. Thus, the anti-tumour effects of fruit peel polyphenols (Flavin7) in the chemoprevention of N-methyl-N-nitrosourea-induced mammary carcinogenesis in female rats were evaluated.

METHODS

Lyophilized substance of Flavin7 (F7) was administered at two concentrations of 0.3 and 3 % through diet. The experiment was terminated 14 weeks after carcinogen administration, and mammary tumours were removed and prepared for histopathological and immunohistochemical analysis. In addition, using an in vitro cytotoxicity assay, apoptosis and proliferation after F7 treatment in human breast adenocarcinoma (MCF-7) cells were performed.

RESULTS

High-dose F7 suppressed tumour frequency by 58 % (P < 0.001), tumour incidence by 24 % (P < 0.05), and lengthened latency by 8 days (P > 0.05) in comparison with the control rats, whereas lower dose of F7 was less effective. Histopathological analysis of tumours showed significant decrease in the ratio of high-/low-grade carcinomas after high-dose F7 treatment. Immunohistochemical analysis of rat carcinoma cells in vivo found a significant increase in caspase-3 expression and significant decrease in Bcl-2, Ki67, and VEGFR-2 expression in the high-dose group. Both doses demonstrated significant positive effects on plasma lipid metabolism in rats. F7 significantly decreased survival of MCF-7 cells in vitro in MTT assay by dose- and time-dependent manner compared to control. F7 prevented cell cycle progression by significant enrichment in G1 cell populations. Incubation with F7 showed significant increase in the percentage of annexin V-/PI-positive MCF-7 cells and DNA fragmentation.

CONCLUSIONS

Our results reveal a substantial tumour-suppressive effect of F7 in the breast cancer model. We propose that the effects of phytochemicals present in this fruit extract are responsible for observed potent anti-cancer activities.

Scutellariae radixInduces Apoptosis in Chemoresistant SCC-25 Human Tongue Squamous Carcinoma Cells

Scutellariae radix is one of the most widely used anticancer herbal medicines in several Asian countries, including Korea, Japan, and China. Squamous cell carcinoma (SCC) is one of the most common head and neck carcinomas, which is highly invasive and metastatic, and can potentially develop chemoresistance. Therefore, new effective treatment methods are urgently needed. We determined the effects of Scutellariae radix on SCC-25 cells using the WST-1 assay, F-actin staining, flow cytometry analysis, immunofluorescence staining, and western blot analysis. Scutellariae radix treatment inhibited SCC-25 cell growth in a dose- and time-dependent manner, but it did not inhibit HaCaT (human keratinocyte) cell growth. Changes in cell morphology and disruption of filamentous (F)-actin organization were observed. Scutellariae radix-induced apoptosis as indicated by the translocation of cytochrome c and apoptosis-inducing factor (AIF) into the nucleus and cytosol. Scutellariae radix-induced an increase in cells with sub-G1 DNA content, and increased Bax, cleaved caspase-3, caspase-7, caspase-9, DNA fragmentation factor 45 (DFF 45), and poly(ADP-ribose) polymerase-1 (PARP-1) expression levels. Furthermore, increased expression of phosphorylated mitogen-activated protein kinase (MAPK)-related proteins was detected. The antitumor effect of Scutellariae radix was due to decreased cell proliferation, changes in cell morphology, and the activation of caspase and MAPK pathways. Taken together, the findings of this study highlight the anticancer activity of Scutellariae radix in chemoresistant SCC-25 oral squamous carcinoma cells.

Inducing apoptosis effect of caffeic acid 3,4-dihydroxy-phenethyl ester on the breast cancer cells

To explore the antitumor effect of caffeic acid 3,4-dihydroxy-phenethyl ester (CADPE) on the breast cancer cell lines and illuminate the related mechanism. After treatment with different concentrations of CADPE for 24, 48, and 72 h, cell proliferation ability of the breast cancer cell lines MDA-MB-231 and MDA-MB-435 was analyzed by the MTT. Changes of the cell cycles were evaluated by PI staining. Cell apoptosis was examined by flow cytometry after Annexin V/7AAD double staining. Nuclear morphologic changes were observed under the inverted fluorescence microscope after staining with Hoechst 33342. Mitochondrial membrane potential and reactive oxygen species (ROS) level were estimated by JC-1 and DCFH-DA staining. In addition, the expression level of mitochondrial signaling pathway proteins Bcl-2, Bax, and caspase-3 were evaluated by Western blot. CADPE has the distinct cytotoxic effect to the breast cancer cells, and the effect is dose dependent. It did not change the cell cycles but induced the cell apoptosis of the breast cancer cells. At the same time, after CADPE treatment, the expression levels of caspase-3 and Bax in the breast cancer cells were upregulated and Bcl-2 expression was declined. The ROS level in the breast cancer cells was enhanced, and mitochondrial membrane potential of the cells was downregulated. CADPE has the antitumor functions. It can induce the cell apoptosis through downregulating Bcl-2 expression, enhancing Bax and caspase-3 expression levels, upregulating ROS level and reducing the mitochondrial membrane potential of the breast cancer cells to trigger the mitochondrial signal pathway.