Inhibitory effects of andrographolide on migration and invasion in human non-small cell lung cancer A549 cells via down-regulation of PI3K/Akt signaling pathway. Eur J Pharmacol. 2010;632:23-32. [PMID: 20097193 DOI: 10.1016/j.ejphar.2010.01.009]

Cytotoxic activity and apoptosis-inducing potential of di-spiropyrrolidino and di-spiropyrrolizidino oxindole andrographolide derivatives

Anticancer role of andrographolide is well documented. To find novel potent derivatives with improved cytotoxicity than andrographolide on cancer cells, two series of di-spiropyrrolidino- and di-spiropyrrolizidino oxindole andrographolide derivatives prepared by cyclo-addition of azomethine ylide along with sarcosine or proline (viz. sarcosine and proline series respectively) and substitution of different functional groups (-CH3, -OCH3 and halogens) were examined for their cytotoxic effect on a panel of six human cancer cell lines (colorectal carcinoma HCT116 cells, pancreatic carcinoma MiaPaCa-2 cells, hepatocarcinoma HepG2 cells, cervical carcinoma HeLa cells, lung carcinoma A549 and melanoma A375 cells). Except halogen substituted derivatives of proline series (viz. CY2, CY14 and CY15 for Br, Cl and I substitution respectively), none of the other derivatives showed improved cytotoxicity than andrographolide in the cancer cell lines examined. Order of cytotoxicity of the potent compounds is CY2>CY14>CY15>andrographolide. Higher toxicity was observed in HCT116, MiaPaCa-2 and HepG2 cells. CY2, induced death of HCT116 (GI50 10.5), MiaPaCa-2 (GI50 11.2) and HepG2 (GI50 16.6) cells were associated with cell rounding, nuclear fragmentation and increased percentage of apoptotic cells, cell cycle arrest at G1 phase, ROS generation, and involvement of mitochondrial pathway. Upregulation of Bax, Bad, p53, caspases-3,-9 and cleaved PARP; downregulation of Bcl-2, cytosolic NF-κB p65, PI3K and p-Akt; translocation of P53/P21, NF-κB p65 were seen in CY2 treated HCT116 cells. Thus, three halogenated di-spiropyrrolizidino oxindole derivatives of andrographolide are found to be more cytotoxic than andrographolide in some cancer cells. The most potent derivative, CY2 induced death of the cancer cells involves ROS dependent mitochondrial pathway like andrographolide.

The HLJ1-targeting drug screening identified Chinese herb andrographolide that can suppress tumour growth and invasion in non-small-cell lung cancer

HLJ1 is a novel tumour suppressor and is a potential druggable target for non-small-cell lung cancer (NSCLC). In this report, using a promoter-containing enhancer region as the HLJ1-targeting drug-screening platform, we identified several herbal compounds from a Chinese herbal bank with the capacity to enhance HLJ1 promoter activity and suppress tumour growth and invasion of NSCLC. Among the herbal drugs identified, the andrographolide (from Andrographis paniculata [Burm. f.] Nees.) most significantly induced HLJ1 expression and suppressed tumorigenesis both in vitro and in vivo. The andrographolide upregulates HLJ1 via JunB activation, which modulates AP-2α binding at the MMP-2 promoter and represses the expression of MMP-2. In addition, silencing of HLJ1 partially reverses the inhibition of cancer-cell invasion by andrographolide. Microarray transcriptomic analysis was performed to comprehensively depict the andrographolide-regulated signalling pathways. We showed that andrographolide can affect 939 genes (analysis of variance, false discovery rate < 0.05) that are dominantly involved in the cell cycle, apoptosis and adhesion-related biological signalling, including mitogen-activated protein kinase, focal adhesion and tight junction pathways, indicating the diverse effects of andrographolide on anticancer invasion and proliferation. In conclusion, the HLJ1-targeting drug-screening platform is useful for screening of novel anticancer compounds. Using this platform, we identified andrographolide is a promising new anticancer agent that could suppress tumour growth and invasion in NSCLC.

Inhibition of matrix metalloproteinases and inducible nitric oxide synthase by andrographolide in human osteoarthritic chondrocytes

OBJECTIVE

The aim of this study was to investigate the effects of andrographolide on matrix metalloproteinases (MMP) 1, 3, and 13 and inducible nitric oxide synthase (iNOS) in human articular chondrocytes from osteoarthritic cartilage.

METHODS

Passaged chondrocytes were pretreated with or without andrographolide for 2 h, followed by coincubation with interleukin-1 beta (IL-1β) 1 ng/ml for 24 h. Expression levels of MMP-1, 3, and 13, tissue inhibitor of metalloproteinase-1 (TIMP-1), and iNOS were evaluated using real-time-quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blotting. Nitric oxide (NO) was analyzed using the Griess reaction assay. Involvement of nuclear factor kappa B (NF-κB) was assessed by Western blotting, transient transfection, and luciferase reporter assay.

RESULTS

Andrographolide tested in these in vitro studies was found be an effective antiarthritic agent, as evidenced by potent inhibition of MMP-1, 3, and 13 and iNOS expression, as well as upregulation of TIMP-1 in IL-1β-stimulated human articular chondrocytes (p < 0.05). The mechanism of andrographolide's inhibitory effects was mediated by attenuating the activation of NF-κB in human chondrocytes in the presence of IL-1β.

CONCLUSIONS

Andrographolide was a potent inhibitor of the production of inflammatory and catabolic mediators by chondrocytes, suggesting that this natural compound may merit consideration as a therapeutic agent for treating and preventing osteoarthritis.

Andrographolide and its analogues: versatile bioactive molecules for combating inflammation and cancer

1. Andrographis paniculata (Burm. f) Nees, commonly known as 'king of bitters', is a herbaceous plant belonging to the Family Acanthaceae. It has been widely used for centuries in Asian countries like China, India, Thailand and Malaysia for the treatment of sore throat, flu and upper respiratory tract infections. 2. Andrographolide, 14-deoxy-11,12-didehydroandrographolide and neoandrographolide are examples of the major labdane diterpenoids isolated from A. paniculata. These bioactive molecules have exhibited varying degrees of anti-inflammatory and anticancer activities in both in vitro and in vivo experimental models of inflammation and cancer. 3. Extensive libraries of andrographolide analogues have been synthesised mainly by modifying the α,β-unsaturated γ-butyrolactone moiety, the two double bonds Δ(8,(17)) and Δ(12,(13)) and the three hydroxyls at C-3 (secondary), C-14 (allylic) and C-19 (primary). Many of these synthetic analogues exhibit superior anticancer activity over the naturally occurring andrographolides. 4. Andrographolide and its derivatives have been shown to have anti-inflammatory effects in experimental models of asthma, stroke and arthritis, as well as in patients with upper respiratory tract infections. Andrographolide reduces the production of cytokines, chemokines, adhesion molecules, nitric oxide and lipid mediators, probably via inhibition of the nuclear factor (NF)-κB signalling pathway. 5. The anticancer mechanisms for andrographolide include inhibition of Janus tyrosine kinases-signal transducers and activators of transcription, phosphatidylinositol 3-kinase and NF-κB signalling pathways, suppression of heat shock protein 90, cyclins and cyclin-dependent kinases, metalloproteinases and growth factors, and the induction of tumour suppressor proteins p53 and p21, leading to inhibition of cancer cell proliferation, survival, metastasis and angiogenesis. 6. Andrographolide drug discovery is a promising strategy for the development of a novel class of anti-inflammatory and anticancer drugs.

Berberine, an isoquinoline alkaloid, inhibits the metastatic potential of breast cancer cells via Akt pathway modulation

Berberine (BBR) is a natural alkaloid with significant antitumor activities against many types of cancer cells. In this study, we investigated the molecular mechanisms by which BBR repressed the metastatic potential of breast cancer cells. BBR was found to downregulate the enzymatic activities and expression levels of matrix metalloproteinases 2 and 9 (MMP2 and MMP9, respectively). The BBR-mediated suppression of MMP2 and MMP9 involved the inhibition of the Akt/nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1) signaling pathways. Furthermore, BBR repressed the expression of the Akt protein by modulating the mRNA expression level and protein degradation of Akt. In conclusion, this study suggests that BBR can reduce the metastatic potential of highly metastatic breast cancer cells and may be a useful adjuvant therapeutic agent in the treatment of breast cancer by targeting the Akt pathway.

Andrographolide exerted its antimicrobial effects by upregulation of human β-defensin-2 induced through p38 MAPK and NF-κB pathway in human lung epithelial cells

Andrographis paniculata (Burm. f) Nees is a traditional herbal medicine for the treatment of infection and inflammation in China. Andrographolide (andro) is one of the major components. Human β-defensin-2 (hBD-2) is an inducible antimicrobial peptide that plays an important role in innate immunity. The present study aimed to investigate the effect of andro on upregulation of hBD-2 and the key signaling pathways involved in andro-induced hBD-2 expression. Real-time reverse transcription – PCR and Western blot assays showed that andro (1.0–10 µmol/L) can upregulate the expression of hBD-2 in a dose-dependent manner. Further studies suggested that hBD-2 mRNA and protein expression in responsive to andro were attenuated by pretreatment with SB203580 (an inhibitor of p38 mitogen-activated protein kinase (p38 MAPK)), MG-132 (an inhibitor of nuclear factor κB (NF-κB)), and an NF-κB activator inhibitor, but not by an inhibitor of ERK (PD98059) or by an inhibitor of JNK(SP600125). Moreover, we found that a second p38 MAPK inhibitor (SB202190) significantly blocked andro-mediated hBD-2 induction in SPC-A-1 lung epithelial cells. Finally, the p-c-Jun transcription factor activity assay also showed that AP-1 activity was induced by andro compared with the untreated group. We conclude that andro may exert its antimicrobial effects by upregulating the expression of hBD-2 through the p38 MAPK and NF-κB pathway.

Cucurbitacin B inhibits 12-O-tetradecanoylphorbol 13-acetate-induced invasion and migration of human hepatoma cells through inactivating mitogen-activated protein kinase and PI3K/Akt signal transduction pathways

AIM

  Cucurbitacin B (CuB) is an active component isolated from various plants used as folk medicine in Asian countries and has shown diverse antitumor activities. There is, however, no documented effect of CuB on the migration and invasion of human hepatoma cells yet. The purpose of this study was to assess the effect of CuB on the migration and invasion of hepatoma cells and to explore the possible mechanism.

METHODS

  Human hepatoma cell lines HepG2 and BEL-7402 were used for the study. Effects of CuB on cancer cell migration and invasion were evaluated in vitro with wound healing and transwell assays. The effect of CuB on the expression of matrix metalloproteinase (MMP)-9, mitogen-activated protein kinases (MAPKs), Akt, nuclear factor-κB (NF-κB), c-Fos and c-Jun was investigated with gelatin zymography and/or western blotting.

RESULTS

  Cucurbitacin B has significantly suppressed 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cell invasion and migration in a concentration-dependent manner, which was accompanied with suppression of TPA-induced MMP-9 expression through inactivation of phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38 and Akt. In the nucleus, it has also strongly suppressed TPA-stimulated expression of NF-κB, c-Jun and c-Fos.

CONCLUSION

  Cucurbitacin B has a potential value for suppressing metastasis of human hepatoma cells through suppressing the expression of MMP-9.

Gambogic acid inhibits TNF-α-induced invasion of human prostate cancer PC3 cells in vitro through PI3K/Akt and NF-κB signaling pathways

AIM

To investigate the mechanisms underlying the inhibitory effect of gambogic acid (GA) on TNF-α-induced metastasis of human prostate cancer PC3 cells in vitro.

METHODS

TNF-α-mediated migration and invasion of PC3 cells was examined using migration and invasion assays, respectively. NF-κB transcriptional activity and nuclear translocation were analyzed with luciferase reporter gene assays, immunofluorescence assays and Western blots. The ability of p65 to bind the promoter of Snail, an important mesenchymal molecular marker, was detected using a chromatin immunoprecipitation (ChIP) assay. After treatment with Snail-specific siRNA, the expression of invasiveness-associated genes was measured using quantitative real-time PCR and Western blot.

RESULTS

GA significantly inhibited the viability of PC3 cells at 1-5 μmol/L, but did not produce cytotoxic effect at the concentrations below 0.5 μmol/L. GA (0.125-0.5 μmol/L) dose-dependently inhibited the migration and invasion of PC3 cells induced by TNF-α (10 ng/mL). Moreover, the TNF-α-mediated activation of phosphatidylinositol-3-OH kinase/protein kinase B (PI3K/Akt) and NF-κB pathways was suppressed by GA (0.5 μmol/L). Furthermore, this anti-invasion effect of GA was associated with regulation of Snail. Snail expression was significantly down-regulated by treatment with GA (0.5 μmol/L) in the TNF-α-stimulated PC3 cells.

CONCLUSION

GA inhibits TNF-α-induced invasion of PC3 cells via inactivation of the PI3K/Akt and NF-κB signaling pathways, which may offer a novel approach for the treatment of human prostate cancer.

Suppression of matrix metalloproteinase-9 expression by andrographolide in human monocytic THP-1 cells via inhibition of NF-κB activation

There is much evidence indicating that human leukemic cells and monocytes/macrophages synthesize, and secrete, several matrix metalloproteinases (MMPs), and participate in the degradation of extracellular matrix components in tissue lesions. In this study, we investigated the effects and mechanisms of andrographolide, extracted from the herb Andrographis paniculata, on human monocytic MMPs expression and activation. Andrographolide (1-50 μM) exhibited concentration-dependent inhibition of MMP-9 activation, induced by either tumor necrosis factor-α (TNF-α), or lipopolysaccharide (LPS), in THP-1cells. In addition, andrographolide did not present an inhibitory effect on MMP-9 enzymatic activity at a concentration of 50 μM. By contrast, enzyme-linked immunosorbent assay (ELISA) showed that andrographolide partially affect TIMP-1 levels. Western blot analysis showed that both TNF-α, and LPS stimulators attenuated MMP-9 protein expression in a concentration-dependent manner. Using reverse transcription polymerase chain reaction (RT-PCR), we found that andrographolide suppressed expression of MMP-9 messenger RNA. Furthermore, we also found that andrographolide could significantly inhibit the degradation of inhibitor-κB-α (IκB-α) induced by TNF-α. We used electrophoretic mobility shift assay and reporter gene detection to show that andrographolide also markedly inhibited NF-κB signaling, anti-translocation and anti-activation. In conclusion, we demonstrate that andrographolide attenuates MMP-9 expression, and its main mechanism might involve the NF-κB signal pathway. These results provide new opportunities for the development of new anti-inflammatory and leukemic therapies.

EGCG inhibits the invasion of highly invasive CL1-5 lung cancer cells through suppressing MMP-2 expression via JNK signaling and induces G2/M arrest

Tumor metastasis is the main obstacle to the treatment of lung cancer. According to previous findings, matrix metalloproteinase-2 (MMP-2) is closely correlated with metastatic potential in lung cancer. This study showed that epigallocatechin-3-gallate (EGCG), a natural polyphenol in green tea, is a potent inhibitor of MMP-2 expression. EGCG effectively suppressed the invasion and migration of highly invasive CL1-5 lung cancer cells. Gelatin zymography, Western blot analysis, and RT-PCR were used to investigate the effects of EGCG on MMP-2 expression. The effects of EGCG on cell cycle and apoptosis were determined by flow cytometry analysis. To investigate the effects of EGCG on cell migration and cell invasion, Transwell migration/invasion assays were used. EGCG downregulated MMP-2 expression at the transcriptional level in CL1-5 cells. Moreover, the treatment of CL1-5 cells with EGCG caused downregulation of c- Jun N-terminal kinase (JNK), resulting in repression of the translocation of transcriptional factors, Sp1, and NF-κB, from the cytosol into the nucleus. In addition, EGCG significantly and synergistically enhanced the antitumor effects of the clinical drug, docetaxel, in CL1-5 cells. Further, EGCG induced G2/M arrest at dosages higher than those of suppression in cell invasion in CL1-5 cells. These results reveal that EGCG might decrease MMP-2 mRNA expression through JNK signaling, further suggesting that a combination of EGCG and docetaxel may be a promising strategy to help increase the efficacy of docetaxel in suppressing metastasis in lung cancer cells. In addition, EGCG may suppress cell proliferation in CL1-5 cells through inducing G2/M arrest.

Potential mechanism of interleukin-8 production from lung cancer cells: an involvement of EGF-EGFR-PI3K-Akt-Erk pathway

Tumor inflammatory microenvironment is considered to play the role in the sensitivity of tumor cells to therapies and prognosis of lung cancer patients. Interleukin-8 (IL-8) is one of critical chemo-attractants responsible for leukocyte recruitment, cancer proliferation, and angiogenesis. The present study aimed at investigating potential mechanism of IL-8 production from human non-small cell lung cancer (NSCLC) SPC-A1 cells. We initially found that EGF could directly stimulate IL-8 production, proliferation, and bio-behaviors of lung cancer cells through the activation of EGFR, PI3K, Akt, and Erk signal pathway. EGF-stimulated IL-8 production, phosphorylation of Akt and Erk, and cell proliferation and movement could be inhibited by EGFR inhibitor (Erlotinib), PI3K inhibitor (GDC-0941 BEZ-235 and SHBM1009), and ERK1/2 inhibitor (PD98059). Our data indicate that IL-8 production from lung cancer cells could be initiated by their own produced factors, leading to the recruitment of inflammatory cells in the cancer tissue, and the formation of inflammatory microenvironment. Thus, it seems that the signal pathway of EGFR-PI3K-Akt-Erk can be the potential target of therapies for inflammatory microenvironment in lung cancer.

Inhibition of TNF-α-Induced Inflammation by andrographolide via down-regulation of the PI3K/Akt signaling pathway

Andrographolide (1), an active constituent of Andrographis paniculata, decreased tumor necrosis factor-α (TNF-α)-induced intercellular adhesion molecule-1 (ICAM-1) expression and adhesion of HL-60 cells onto human umbilical vein endothelial cells (HUVEC), which are associated with inflammatory diseases. Moreover, 1 abolished TNF-α-induced Akt phosphorylation. Transfection of an activated Akt1 cDNA vector increased Akt phosphorylation and ICAM-1 expression like TNF-α. In addition, 1 and LY294002 blocked TNF-α-induced IκB-α degradation and nuclear p65 protein accumulation, as well as the DNA-binding activity of NF-κB. Compound 1 exhibits anti-inflammatory properties through the inhibition of TNF-α-induced ICAM-1 expression. The anti-inflammatory activity of 1 may be associated with the inhibition of the PI3K/Akt pathway and downstream target NF-κB activation in HUVEC cells.

Andrographolide targets androgen receptor pathway in castration-resistant prostate cancer

Androgen receptor (AR) signaling not only plays a pivotal role in the development of androgen-dependent prostate cancer but is also important in the growth and survival of castration-resistant prostate cancer (CRPC). The first line of treatment of androgen-dependent prostate cancer is the use of androgen deprivation therapy. However, most patients will eventually relapse due to development of CRPC. Thus, development of a strategy to target AR for treatment of CRPC is urgently needed. The authors have previously identified andrographolide as an inhibitor of interleukin-6, which can suppress tumor growth of prostate cancer cells by screening compounds from the Prestwick Natural compound library. In this study, they identified that andrographolide can inhibit AR expression and prostate cancer cell growth and induce apoptosis. Andrographolide is able to down-regulate AR expression at both mRNA and protein levels, prevents its nuclear translocation, and inhibits transactivation of its target genes. Andrographolide prevents the binding of Hsp90 to AR, resulting in proteasome-mediated AR degradation. Furthermore, andrographolide inhibits castration-resistant C4-2 cell growth by reducing AR expression and activity. Thus, andrographolide can be developed as a potential therapeutic agent for prostate cancer by inhibition of androgen receptor signaling.

Antimetastatic potential of cardiotoxin III involves inactivation of PI3K/Akt and p38 MAPK signaling pathways in human breast cancer MDA-MB-231 cells

AIM

The aim of this study is to determine whether cardiotoxin III (CTX III) inhibited the metastasis in MDA-MB-231 cells and to further explain its possible mechanisms.

MAIN METHODS

The MTT assay, wound healing assay, Boyden chamber invasion assay, zymography analysis, reverse transcriptase polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), inhibitor assay, and Western blot analysis were used to reveal molecular events of CTX III in this study.

KEY FINDINGS

During treatment with non-toxic doses of CTX III, not only cell migration and invasion were markedly suppressed but the expression/activity of matrix metalloproteinase-9 (MMP-9) was also significantly and selectively suppressed in a concentration-dependent manner. In addition, CTX III decreased the nuclear protein level of nuclear factor kappa B (NF-κB), and pretreatment with NF-κB inhibitor (PDTC) or IκB protease inhibitor (TPCK) also reduced MMP-9 expression/activity and cell migration. Our biochemical assays indicated that CTX III potently suppressed the phosphorylation of p38 mitogen-activated protein kinase (MAPK), phosphatidylinositide-3-kinase (PI3K) and Akt. Additionally, the treatment of inhibitors specific for p38 MAPK (SB203580) or PI3K (wortmannin) to cells could result in a reduced expression of NF-κB and MMP-9 expression, concomitantly with an inhibition on cell metastasis.

SIGNIFICANCE

These results demonstrated that CTX III inhibition of MDA-MB-231 cells may occur through inactivation of both PI3K/Akt and p38 MAPK signaling pathways, exerting inhibitory effects on NF-κB transcriptional factor, thereby decreasing the activity of MMP-9 and then posing an anti-metastatic effect in the cells.

Antimetastatic effect and mechanism of ovatodiolide in MDA-MB-231 human breast cancer cells

Cancer metastasis is a primary cause of cancer death. Ovatodiolide, a bioactive cembrane-type diterpenoid isolated from Anisomeles indica (L.) Kuntze (Labiatae), has been shown to inhibit the growth and proliferation of cancer cells. However, the anti-metastatic effects of ovatodiolide on highly metastatic human breast cancer MDA-MB-231 cells remain unclear. In this study, we first noted that ovatodiolide inhibited MDA-MB-231 cell migration and invasion by wound-healing assay and Boyden chamber assay. Western blot, gelatin zymography and reversed transcription-PCR analysis showed that ovatodiolide significantly and selectively suppressed the expression, activation, and mRNA of matrix metalloproteinase-9 (MMP-9) in a concentration-dependent manner. Ovatodiolide significantly decreased the nuclear level of nuclear factor kappaB (NF-κB), increased inhibitor of kappaBα (IκBα) through preventing phosphorylation of upstream signal IκB kinase (IKK). Pretreatment with a specific NF-κB inhibitor (PDTC) and an IκB protease inhibitor (TPCK) also reduced MMP-9 activity, cell migration and cell invasion. Moreover, ovatodiolide can suppress activation of c-Jun N-terminal kinase, p38 mitogen-activated protein kinase, phosphatidylinositol 3-kinase and Akt, while it did not affect phosphorylation of extracellular signal regulating kinases (ERK)1/2. Additionally, the treatment of inhibitors specific for PI3K (wortmannin), JNK (SP600125) or p38 MAPK (SB203580) to MDA-MB-231 cells could result in a reduced activation of MMP-9, concomitantly with a marked inhibition on cell migration and invasion. Taken together, these results demonstrate that ovatodiolide inhibits the metastatic ability of MDA-MB-231 cells by reducing MMP-9 activity through suppressing JNK, p38 MAPK and PI3K/Akt signaling pathways and inhibiting NF-κB activity. These results are the first to reveal the function of ovatodiolide in tumor metastasis and its underlying molecular mechanism, thus suggesting ovatodiolide to be a promising antimetastatic agent.

Ellagic acid prevents rat colon carcinogenesis induced by 1, 2 dimethyl hydrazine through inhibition of AKT-phosphoinositide-3 kinase pathway

Colon cancer is the third most malignant neoplasm in the world and chemoprevention through dietary intervention is an emerging option to reduce its mortality. Ellagic acid (EA) a major component of berries possesses attractive biological deeds. This study is aimed to investigate the effect of ellagic acid in fostering apoptosis in 1,2-dimethyl hydrazine (DMH) mediated experimental colon carcinogenesis model. Wistar male rats were segregated into four groups: group I-control rats, group II-rats received ellagic acid (60 mg/kg body weight p.o. every day), rats in group III-induced with DMH (20 mg/kg body weight, s.c.) for 15 weeks, DMH-induced group IV rats were initiated with ellagic acid treatment. The present study is designed to explore the significance of phosphoinositide-3-kinase (PI3K)/Akt molecular pathway as well as ellagic acid's chemopreventive effect in colon cancer. DMH-induced rats exhibited elevated expressions of PI3K and Akt as confirmed by immunofluorescence, immunoblot and confocal microscopic analysis. Mechanistically, ellagic acid was found to prevent PI3K/Akt activation that in turn, results in modulation of its downstream Bcl-2 family proteins. Bax expression and caspase-3 activation was noted after ellagic acid supplementation leading to elevation of cytochrome c (cyt c) levels and finally cell death. These observations were supported by the DNA fragmentation results, which showed the occurrence of apoptosis. This study reveals the involvement of PI3K-Akt signaling through which ellagic acid induces apoptosis and subsequently suppresses colon cancer during DMH-induced rat colon carcinogenesis. In conclusion, our findings demonstrate that ellagic acid begets apoptosis in DMH-induced colon carcinoma.

Antimetastatic effects of Phyllanthus on human lung (A549) and breast (MCF-7) cancer cell lines

Background

Current chemotherapeutic drugs kill cancer cells mainly by inducing apoptosis. However, they become ineffective once cancer cell has the ability to metastasize, hence the poor prognosis and high mortality rate. Therefore, the purpose of this study was to evaluate the antimetastatic potential of Phyllanthus (P. niruri, P. urinaria, P. watsonii, and P. amarus) on lung and breast carcinoma cells.

Methodology/Principal Findings

Cytotoxicity of Phyllanthus plant extracts were first screened using the MTS reduction assay. They were shown to inhibit MCF-7 (breast carcinoma) and A549 (lung carcinoma) cells growth with IC₅₀ values ranging from 50–180 µg/ml and 65–470 µg/ml for methanolic and aqueous extracts respectively. In comparison, they have lower toxicity on normal cells with the cell viability percentage remaining above 50% when treated up to 1000 µg/ml for both extracts. After determining the non-toxic effective dose, several antimetastasis assays were carried out and Phyllanthus extracts were shown to effectively reduce invasion, migration, and adhesion of both MCF-7 and A549 cells in a dose-dependent manner, at concentrations ranging from 20–200 µg/ml for methanolic extracts and 50–500 µg/ml for aqueous extracts. This was followed by an evaluation of the possible modes of cell death that occurred along with the antimetastatic activity. Phyllanthus was shown to be capable of inducing apoptosis in conjunction with its antimetastastic action, with more than three fold increase of caspases-3 and -7, the presence of DNA-fragmentation and TUNEL-positive cells. The ability of Phyllanthus to exert antimetastatic activities is mostly associated to the presence of polyphenol compounds in its extracts.

Conclusions/Significance

The presence of polyphenol compounds in the Phyllanthus plant is critically important in the inhibition of the invasion, migration, and adhesion of cancer cells, along with the involvement of apoptosis induction. Hence, Phyllanthus could be a valuable candidate in the treatment of metastatic cancers.

Epithelial phosphatidylinositol-3-kinase signaling is required for β-catenin activation and host defense against Citrobacter rodentium infection

Citrobacter rodentium infection of mice induces cell-mediated immune responses associated with crypt hyperplasia and epithelial β-catenin signaling. Recent data suggest that phosphatidylinositol-3-kinase (PI3K)/Akt signaling cooperates with Wnt to activate β-catenin in intestinal stem and progenitor cells through phosphorylation at Ser552 (P-β-catenin(552)). Our aim was to determine whether epithelial PI3K/Akt activation is required for β-catenin signaling and host defense against C. rodentium. C57BL/6 mice were infected with C. rodentium and treated with dimethyl sulfoxide (DMSO) (vehicle control) or with the PI3K inhibitor LY294002 or wortmannin. The effects of infection on PI3K activation and β-catenin signaling were analyzed by immunohistochemistry. The effects of PI3K inhibition on host defense were analyzed by the quantification of splenic and colon bacterial clearance, and adaptive immune responses were measured by real-time PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Increased numbers of P-β-catenin(552)-stained epithelial cells were found throughout expanded crypts in C. rodentium colitis. We show that the inhibition of PI3K signaling attenuates epithelial Akt activation, the Ser552 phosphorylation and activation of β-catenin, and epithelial cell proliferative responses during C. rodentium infection. PI3K inhibition impairs bacterial clearance despite having no impact on mucosal cytokine (gamma interferon [IFN-γ], tumor necrosis factor [TNF], interleukin-17 [IL-17], and IL-1β) or chemokine (CXCL1, CXCL5, CXCL9, and CXCL10) induction. The results suggest that the host defense against C. rodentium requires epithelial PI3K activation to induce Akt-mediated β-catenin signaling and the clearance of C. rodentium independent of adaptive immune responses.

Andrographolide and 14-deoxy-11,12-didehydroandrographolide from Andrographis paniculata attenuate high glucose-induced fibrosis and apoptosis in murine renal mesangeal cell lines

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of Andrographis paniculata Nees are used for various ethnomedical conditions including hyperglycemia and hypertension complications.

AIM OF THE STUDY

The purpose of this study is to evaluate the anti-diabetic nephropathy effect of diterpene lactones andrographolide (AP1) and 14-deoxy-11,12-didehydroandrographolide (AP2) from Andrographis paniculata.

MATERIALS AND METHODS

MES-13, a SV40-transformed murine glomerular mesangial cell line, was cultured in high concentration of glucose to induce diabetic nephropathy phenotypes, which include secretion of extracellular matrix protein fibronectin, cytokine TGF-β, states of oxidative stress, and apoptosis marker caspase-3.

RESULTS

Our data suggest that addition of compounds AP1 or AP2 reduces the phenotypes indicating diabetic nephropathy in MES-13 cells. The compound AP2 showed potent activity than AP1 in the reduction of apoptosis marker caspase-3, fibrosis marker TGF-β, and PAI-1. Furthermore, AP1 and AP2 do not have antioxidant ability in acellular environment; however, addition of AP1 and AP2 reduced intracellular oxidative states in high glucose cultured MES-13 cells.

CONCLUSION

This is the first report on anti-diabetic nephropathy effect of AP1 and AP2 in part due to the regulation of intracellular signaling transduction, not mere clearance of reactive oxygen species. Thus, this study may be useful for drug development or food supplement for diabetes and nephropathy from Andrographis paniculata.

Andrographolide-induced pi class of glutathione S-transferase gene expression via PI3K/Akt pathway in rat primary hepatocytes

Andrographis paniculata is an herb widely used in China, Korea, and India for its anti-hepatotoxic, anti-viral, and anti-inflammatory effects. Andrographolide is the major bioactive diterpene lactone in A. paniculata. The pi class of glutathione S-transferase (GSTP) is one of the phase II biotransformation enzymes. Our previous study indicated that andrographolide upregulates the expression of GSTP. The aim of this study was to investigate the mechanism by which andrographolide induces GSTP gene expression in rat primary hepatocytes. In hepatocytes treated with 40 μM andrographolide, immunoblots showed maximal Akt phosphorylation at 0.5 h and maximal c-jun phosphorylation at 3 h. However, pretreatment with PI3K inhibitors, wortmannin and LY294002, or siPI3K inhibited the andrographolide-induced phosphorylation of c-jun and GSTP protein expression. EMSA showed that pretreatment with wortmannin, LY294002, or siPI3K attenuated the AP-1-DNA-binding activity caused by andrographolide. Results of immunoprecipitation indicated that nuclear c-fos/c-jun heterodimer increases with andrographolide treatment. Addition of antibodies against c-jun and c-fos decreased nuclear protein bound to the AP-1 consensus DNA sequence. In summary, andrographolide induces GSTP gene expression in rat primary hepatocytes through activation of the PI3K/Akt, phosphorylation of c-jun, nuclear accumulation of AP-1, and subsequent binding to the response element in the gene promoter region.

Induction of heme oxygenase 1 and inhibition of tumor necrosis factor alpha-induced intercellular adhesion molecule expression by andrographolide in EA.hy926 cells

Andrographolide is the most abundant diterpene lactone in Andrographis paniculata, which is widely used as a traditional medicine in Southeast Asia. Heme oxygenase 1 (HO-1) is an antioxidant enzyme encoded by a stress-responsive gene. HO-1 has been reported to inhibit the expression of adhesion molecules in vascular endothelial cells (EC). Intercellular adhesion molecule (ICAM-1) is an inflammatory biomarker that is involved in the adhesion of monocytes to EC. In this study, we investigated the effect of andrographolide on the expression of ICAM-1 induced by tumor necrosis factor alpha (TNF-alpha) in EA.hy926 cells and the possible mechanisms involved. Andrographolide (2.5-7.5 microM) inhibited the TNF-alpha-induced expression of ICAM-1 in a dose-dependent manner and resulted in a decrease in HL-60 cell adhesion to EA.hy926 cells (p < 0.05). In parallel, andrographolide significantly induced the expression of HO-1 in a concentration-dependent fashion (p < 0.05). Andrographolide increased the rate of nuclear translocation of nuclear factor erythroid 2-related 2 (Nrf2) and induced antioxidant response element-luciferase reporter activity. Transfection with HO-1-specific small interfering RNA knocked down HO-1 expression, and the inhibition of expression of ICAM-1 by andrographolide was significantly reversed. These results suggest that stimulation of Nrf2-dependent HO-1 expression is involved in the suppression of TNF-alpha-induced ICAM-1 expression exerted by andrographolide.

Isolation and identification of bioactive compounds in Andrographis paniculata (Chuanxinlian)

Andrographis paniculata (Burm. f.) Nees (Acanthaceae) is a medicinal plant used in many countries. Its major constituents are diterpenoids, flavonoids and polyphenols. Among the single compounds extracted from A. paniculata, andrographolide is the major one in terms of bioactive properties and abundance. Among the andrographolide analogues, 14-deoxy-11,12-didehydroandrographolide is immunostimulatory, anti-infective and anti-atherosclerotic; neoandrographolide is anti-inflammatory, anti-infective and anti-hepatotoxic; 14-deoxyandrographolide is immunomodulatory and anti-atherosclerotic. Among the less abundant compounds from A. paniculata, andrograpanin is both anti-inflammatory and anti-infective; 14-deoxy-14,15-dehydroandrographolide is anti-inflammatory; isoandrographolide, 3,19-isopropylideneandrographolide and 14-acetylandrographolide are tumor suppressive; arabinogalactan proteins are anti-hepatotoxic. The four flavonoids from A. paniculata, namely 7-O-methylwogonin, apigenin, onysilin and 3,4-dicaffeoylquinic acid are anti-atherosclerotic.