Paeonol suppresses chondrosarcoma metastasis through up-regulation of miR-141 by modulating PKCδ and c-Src signaling pathway.

Chondrosarcoma, a primary malignant bone cancer, has potential for local invasion and distant metastasis, especially to the lungs. Patients diagnosed with it show poor prognosis. Paeonol (2'-hydroxy-4'-methoxyacetophenone), the main active compound of traditional Chinese remedy Paeonia lactiflora Pallas, exhibits anti-inflammatory and anti-tumor activity; whether paeonol regulates metastatic chondrosarcoma is largely unknown. Here, we find paeonol do not increase apoptosis. By contrast, at non-cytotoxic concentrations, paeonol suppresses migration and invasion of chondrosarcoma cells. We also demonstrate paeonol enhancing miR-141 expression and miR-141 inhibitor reversing paeonol-inhibited cell motility; paeonol also reduces protein kinase C (PKC)d and c-Src kinase activity. Since paeonol inhibits migration and invasion of human chondrosarcoma via up-regulation of miR-141 via PKCd and c-Src pathways, it thus might be a novel anti-metastasis agent for treatment of metastatic chondrosarcoma.

Resistin protects against 6-hydroxydopamine-induced cell death in dopaminergic-like MES23.5 cells.

Resistin is originally reported as an adipose tissue-specific hormone and is thought to represent a link between obesity and insulin-resistant diabetes. Adipokines exert energy-regulation and has been reported to have neuroprotective effect like leptin, adiponectin, and ghrelin. However, the role of resistin in neuroprotective effect has not been explored. 6-hydroxydopamine (6-OHDA), one of the most investigated Parkinson's disease neurotoxins, is widely used to study mechanisms of cell death in dopaminergic neurons. In the present study, our results show that treatment of resistin protects 6-OHDA-induced cell death in dopaminergic-like MES23.5 cells. Resistin also antagonizes 6-OHDA-induced apoptotic cell death measured by fluorescence-activated cell sorter (FACS) analysis and Hochest 33342 staining. Furthermore, treatment of resistin also dramatically reduces 6-OHDA-mediated ROS production and mitochondria transmembrane potential dissipation. Moreover, expression of 6-OHDA-induced apoptotic markers, such as Bcl-2 degradation, Bax expression, PARP degradation and caspase 3 activity increase, are all attenuated by resistin treatment. Our results also show that resistin induces up-regulation of heat shock protein (Hsp) 32 (heme oxygenase-1, HO-1) and Hsc (heat shock cognate) 70. The protective effect of resistin on 6-OHDA-induced cell death is abolished by HO-1 inhibitor zinc protoporphyrin IX and HSP inhibitor KNK437. These results suggest the neuroprotective effects of resistin against 6-OHDA-induced cell death with the underlying mechanisms of inhibiting oxidative stress and apoptosis. Therefore, we suggest that resistin may provide a useful therapeutic strategy for neurodegenerative diseases such as Parkinson's disease.

D-pinitol inhibits prostate cancer metastasis through inhibition of αVß3 integrin by modulating FAK, c-Src and NF-κB pathways.

Prostate cancer is the most commonly diagnosed malignancy in men and shows a predilection for metastasis to the bone. D-pinitol, a 3-methoxy analogue of d-chiro-inositol, was identified as an active principle in soy foods and legumes, and it has been proven to induce tumor apoptosis and metastasis of cancer cells. In this study, we investigated the anti-metastasis effects of D-pinitol in human prostate cancer cells. We found that D-pinitol reduced the migration and the invasion of prostate cancer cells (PC3 and DU145) at noncytotoxic concentrations. Integrins are the major adhesive molecules in mammalian cells and have been associated with the metastasis of cancer cells. Treatment of prostate cancer cells with D-pinitol reduced mRNA and cell surface expression of αvß3 integrin. In addition, D-pinitol exerted its inhibitory effects by reducing focal adhesion kinase (FAK) phosphorylation, c-Src kinase activity and NF-kB activation. Thus, D-pinitol may be a novel anti-metastasis agent for the treatment of prostate cancer metastasis.

CCN3 increases BMP-4 expression and bone mineralization in osteoblasts.

The nephroblastoma overexpressed (NOV) gene, also called CCN3, regulates differentiation of skeletal mesenchymal cells. Bone morphogenetic proteins (BMPs) play important roles in osteoblast differentiation and bone formation, but the effects of CCN3 on BMP expression and bone formation in cultured osteoblasts are largely unknown. Here we found that CCN3 increased BMP-4 expression and bone nodule formation in cultured osteoblast. Monoclonal antibodies for α5ß1 and αvß5 integrins, and inhibitors of integrin-linked kinase (ILK), p38, and JNK, all inhibited CCN3-induced bone nodule formation and BMP-4 up-regulation of osteoblasts. CCN3 stimulation increased the kinase activity of ILK and phosphorylation of p38 and JNK. Inhibitors of activator protein-1 (AP-1) also suppressed bone nodule formation and BMP-4 expression enhanced by CCN3. Moreover, CCN3-induced c-Jun translocation into the nucleus, and the binding of c-Jun to the AP-1 element on the BMP-4 promoter were both inhibited by specific inhibitors of the ILK, p38, and JNK cascades. Taken together, our results provide evidence that CCN3 enhances BMP-4 expression and bone nodule formation in osteoblasts, and that the integrin receptor, ILK, p38, JNK, and AP-1 signaling pathways may be involved.

Wogonin induces reactive oxygen species production and cell apoptosis in human glioma cancer cells.

Glioma is the most common primary adult brain tumor with poor prognosis because of the ease of spreading tumor cells to other regions of the brain. Cell apoptosis is frequently targeted for developing anti-cancer drugs. In the present study, we have assessed wogonin, a flavonoid compound isolated from Scutellaria baicalensis Georgi, induced ROS generation, endoplasmic reticulum (ER) stress and cell apoptosis. Wogonin induced cell death in two different human glioma cells, such as U251 and U87 cells but not in human primary astrocytes (IC 50 > 100 µM). Wogonin-induced apoptotic cell death in glioma cells was measured by propidine iodine (PI) analysis, Tunnel assay and Annexin V staining methods. Furthermore, wogonin also induced caspase-9 and caspase-3 activation as well as up-regulation of cleaved PARP expression. Moreover, treatment of wogonin also increased a number of signature ER stress markers glucose-regulated protein (GRP)-78, GRP-94, Calpain I, and phosphorylation of eukaryotic initiation factor-2α (eIF2α). Treatment of human glioma cells with wogonin was found to induce reactive oxygen species (ROS) generation. Wogonin induced ER stress-related protein expression and cell apoptosis was reduced by the ROS inhibitors apocynin and NAC (N-acetylcysteine). The present study provides evidence to support the fact that wogonin induces human glioma cell apoptosis mediated ROS generation, ER stress activation and cell apoptosis.

Peptidoglycan induces interleukin-6 expression through the TLR2 receptor, JNK, c-Jun, and AP-1 pathways in microglia.

We recently reported that peptidoglycan (PGN), a cell wall component of the Gram-positive bacterium, induces NF-κB activation and microglia activation. However, PGN-regulated AP-1 activation and cytokine expression in microglia remains unclear. This study investigated how PGN influences the signaling pathway involved in IL-6 production in microglia. IL-6 mRNA and protein level up-regulation were increased by PGN in a concentration- and time-dependent manner. In addition, PGN increased toll-like receptor-2 (TLR2) expression, but not TLR4 receptor up-regulation. Administration of TLR2 siRNA or TLR2 neutralized antibody effectively inhibited PGN-induced IL-6 expression. In contrast, PGN-induced IL-6 mRNA and protein up-regulation were attenuated by the SAPK/JNK (c-Jun N-terminal kinases) inhibitor SP600125. Treatment of microglia with PGN increased levels of JNK phosphorylation and c-Jun phosphorylation, and up-regulated of JNK kinase activity. Treatment of microglia with AP-1 inhibitors (Tanshinone IIA and curcumin) effectively reduced PGN-induced IL-6 expression. PGN also significantly increased c-Fos and phospho-c-Jun translocation to nucleus. In line with this, PGN also increased AP-1-DNA complexes formation, as determined by the electrophoretic mobility shift assay. Furthermore, PGN also increased IL-6 transcription activity determined by transfection with IL-6 promoter construct plasmid. Co-transfection with dominant negative mutant of JNK (DN-JNK), or treatment with SP600125, curcumin, or Tanshinone IIA effectively antagonized PGN-increased IL-6 transcription activity. Our data demonstrate that PGN-induced IL-6 expression is mediated by AP-1 activation through the TLR2 and JNK/c-Jun pathways in microglia.

Cyr61 increases migration and MMP-13 expression via alphavbeta3 integrin, FAK, ERK and AP-1-dependent pathway in human chondrosarcoma cells.

Cysteine-rich 61 (Cyr61), from the CCN gene family, is a secreted and matrix-associated protein, which is involved in many cellular activities such as growth and differentiation. However, the effect of Cyr61 on migration activity in human chondrosarcoma cells is mostly unknown. Here, we found that Cyr61 increased the migration and expression of matrix metalloproteinase (MMP)-13 in human chondrosarcoma cells (JJ012 cells). RGD peptide, alphavbeta3 monoclonal antibody and mitogen-activated protein kinase (MEK) inhibitors (PD98059 and U0126) but not RAD peptide inhibited the Cyr61-induced increase of the migration and MMP-13 upregulation of chondrosarcoma cells. Cyr61 stimulation increased the phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In addition, activator protein-1 (AP-1) decoy oligodeoxynucleotide also suppressed the MMP-13 messenger RNA and enzyme activity enhanced by Cyr61. Moreover, Cyr61 increased the binding of c-Fos and c-Jun to the AP-1 element on the MMP-13 promoter. Taken together, our results indicated that Cyr61 enhances the migration of chondrosarcoma cells by increasing MMP-13 expression through the alphavbeta3 integrin receptor, FAK, ERK, c-Fos/c-Jun and AP-1 signal transduction pathway.

CCL5/CCR5 axis promotes the motility of human oral cancer cells.

CCL5 (previously called RANTES) is in the CC-chemokine family and plays a crucial role in the migration and metastasis of human cancer cells. On the other hand, the effect of CCL5 is mediated via CCR receptor. RT-PCR and flow cytometry studies demonstrated CCR5 but not CCR1 and CCR3 mRNA in oral cancer cell lines, especially higher in those with high invasiveness (SCC4) as compared with lower levels in HSC3 cells and SCC9 cells. Stimulation of oral cancer cells with CCL5 directly increased the migration and metalloproteinase-9 (MMP-9) production. MMP-9 small interfering RNA inhibited the CCL5-induced MMP-9 expression and thereby significantly inhibited the CCL5-induced cell migration. Activations of phospholipase C (PLC), protein kinase Cdelta (PKCdelta), and NF-kappaB pathways after CCL5 treatment was demonstrated, and CCL5-induced expression of MMP-9 and migration activity was inhibited by the specific inhibitor of PLC, PKCdelta, and NF-kappaB cascades. In addition, migration-prone sublines demonstrate that cells with increasing migration ability had more expression of MMP-9, CCL5, and CCR5. Taken together, these results indicate that CCL5/CCR5 axis enhanced migration of oral cancer cells through the increase of MMP-9 production.

CTGF enhances migration and MMP-13 up-regulation via alphavbeta3 integrin, FAK, ERK, and NF-kappaB-dependent pathway in human chondrosarcoma cells.

Tumor malignancy is associated with several features such as proliferation ability and frequency of metastasis. Connective tissue growth factor (CTGF), a secreted protein that binds to integrins, modulates the invasive behavior of certain human cancer cells. However, the effect of CTGF on migration activity in human chondrosarcoma cells is mostly unknown. Here we found that CTGF increased the migration and expression of matrix metalloproteinase (MMP)-13 in human chondrosarcoma cells (JJ012 cells). RGD peptide, alphavbeta3 monoclonal antibody (mAb) and MAPK kinase (MEK) inhibitors (PD98059 and U0126) but not RAD peptide inhibited the CTGF-induced increase of the migration and MMP-13 up-regulation of chondrosarcoma cells. CTGF stimulation increased the phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In addition, treatment of JJ012 cells with NF-kappaB inhibitor (PDTC) or IkappaB protease inhibitor (TPCK) inhibited CTGF-induced cell migration and MMP-13 up-regulation. Stimulation of JJ012 cells with CTGF also induced IkappaB kinase alpha/beta (IKK alpha/beta) phosphorylation, IkappaBalpha phosphorylation, p65 Ser(536) phosphorylation, and kappaB-luciferase activity. The CTGF-mediated increases in kappaB-luciferase activities were inhibited by RGD, PD98059, U0126 or FAK, and ERK2 mutant. Taken together, our results indicated that CTGF enhances the migration of chondrosarcoma cells by increasing MMP-13 expression through the alphavbeta3 integrin, FAK, ERK, and NF-kappaB signal transduction pathway.

AMP-activated protein kinase is involved in COX-2 expression in response to ultrasound in cultured osteoblasts.

It has been shown that ultrasound (US) stimulation accelerates fracture healing in the animal models and in clinical studies. Cyclooxygenase-2 (COX-2) is a crucial mediator in mechanically induced bone formation. AMP-activated protein kinase (AMPK) has reported to sense and regulate the cellular energy status in various cell types. Here we found that US-mediated COX-2 expression was attenuated by LKB1 and AMPKalpha1 small interference RNA (siRNA) in human osteoblasts. Pretreatment of osteoblasts with AMPK inhibitor (araA and compound C), p38 inhibitor (SB203580), NF-kappaB inhibitor (PDTC), IkappaB protease inhibitor (TPCK) and NF-kappaB inhibitor peptide also inhibited the potentiating action of US. US increased the kinase activity and phosphorylation of LKB1, AMPK and p38. Stimulation of osteoblasts with US activated IkappaB kinase alpha/beta (IKKalpha/beta), IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation at Ser(276), p65 and p50 translocation from the cytosol to the nucleus, and kappaB-luciferase activity. US-mediated an increase of IKKalpha/beta activity, kappaB-luciferase activity and p65 and p50 binding to the NF-kappaB element was inhibited by araA, SB203580 and LKB1 siRNA. Our results suggest that US increased COX-2 expression in osteoblasts via the LKB1/AMPKalpha1/p38/IKKalphabeta and NF-kappaB signaling pathway.

Danthron inhibits the migration and invasion of human brain glioblastoma multiforme cells through the inhibition of mRNA expression of focal adhesion kinase, Rho kinases-1 and metalloproteinase-9.

In this study, we investigated the effect of danthron on the cell migration and invasion of human brain glioblastoma multiforme GBM 8401 cells in vitro. The changes of migration and invasion of GBM 8401 cells after treatment with danthron were detected by cell migration assay and cell invasion assay. The levels of mRNA gene expression associated with cell migration and invasion were detected by real-time PCR. Results indicated that human brain glioblastoma multiforme GBM 8401 cells treated with danthron in vitro migrated and invaded less than cells treated with phosphate-buffered saline (PBS) (control). Western blotting showed that danthron inhibited the protein levels of FAK, MMP-7, MMP-9 and uPA in GBM 8401 cells. Real-time PCR assay also showed that danthron inhibited the mRNA expression of matrix metalloproteinase-9 (MMP-9), FAK and ROCK-1 of GBM 8401 cells. These results showed that danthron inhibited invasion and migration of GBM 8401 cells by downregulating mRNA expression associated with these processes, resulting in reduced metastasis. Thus, danthron may be considered a therapeutic agent that can inhibit primary tumor growth and prevent metastasis.

A. cantoniensis inhibits the proliferation of murine leukemia WEHI-3 cells in vivo and promotes immunoresponses in vivo.

Ampelopsis cantoniensis (AC) has been used as a folk medicine for reducing pain in the Taiwanese population. Our previous studies have shown that the crude extract of AC induced apoptosis in human promyelocytic leukemia HL-60 cells. In this study, the in vivo effects of AC on leukemia WEHI-3 cells and immune responses such as phagocytosis and natural killer (NK) cell activity were investigated. The weights of the livers and spleens were decreased in the AC-treated groups compared to the control groups. The AC treatment increased the percentage of CD3 and CD19 marker cells in WEHI-3-injected mice, indicating that the precursors of T and B cells were inhibited. The AC treatment promoted the activity of macrophage phagocytosis in the peripheral blood mononuclear cells (PBMC) and peritoneal cells. It was found that the NK cells from mice after treatment with AC can kill the YAC-1 target cells. Therefore, the AC treatment increased NK cell activity. In conclusion, AC can affect WEHI-3 cells in vivo and promote macrophage and NK cell activities.

Involvement of matrix metalloproteinase-9 in stromal cell-derived factor-1/CXCR4 pathway of lung cancer metastasis.

Lung caner cells have a striking tendency to metastasize to bone. The chemokine stromal cell-derived factor-1 (SDF-1) is constitutively secreted by osteoblasts and bone marrow stromal cells and plays a key role for homing of hematopoietic cells to the bone marrow. Reverse transcriptase-polymerase chain reaction and flow cytometry studies demonstrated SDF-1 receptor (CXCR4) messenger RNA (mRNA) and surface expression of CXCR4 in lung cancer cell lines, especially higher in those with high invasiveness (A549) as compared with lower level in H928 cells and H1299 cells. SDF-1, osteoblast-conditioned medium (OBCM) and stromal cell-conditioned medium all induced the invasiveness of lung cancer cells. Matrix metalloproteinase (MMP)-9 small interfering RNA inhibited the SDF-1alpha- or OBCM-induced MMP-9 expression and thereby significantly inhibited the SDF-1alpha- or OBCM-induced cell invasion. Furthermore, mitogen-activated protein kinase kinase inhibitor PD98059 suppressed SDF-1alpha-induced MMP-9 mRNA expression. Transient transfection with dominant-negative extracellular signal-regulated kinase (ERK) mutant also showed that the ERK-signaling pathway was involved in SDF-1alpha-induced MMP-9 expression. Moreover, nuclear factor-kappaB (NF-kappaB) decoy oligodeoxynucleotide suppressed the MMP-9 promoter activity enhanced by SDF-1alpha. Both mitogen-activated protein kinase kinase inhibitor and ERK mutant also antagonized SDF-1alpha-induced NF-kappaB-driven luciferase promoter activity. Taken together, our results indicated that bone marrow-derived-SDF-1alpha enhances the invasiveness of lung cancer cells by increasing MMP-9 expression through the CXCR4/ERK/NF-kappaB signal transduction pathway.

Diallyl disulfide (DADS) induces apoptosis in human cervical cancer Ca Ski cells via reactive oxygen species and Ca2+-dependent mitochondria-dependent pathway.

The mechanisms of apoptosis induced by diallyl disulfide (DADS) were explored in human cervical cancer Ca Ski cells. Flow cytometric analysis, DNA gel electrophoresis and DAPI staining demonstrated that DADS induced apoptosis in Ca Ski cells. DADS induced apoptosis through the production of reactive oxygen species and Ca2+, and induced abrogation of mitochondrial membrane potential (Deltapsim) and cleavage of Bid protein (t-Bid). DADS increased the levels of p53, p21 and Bax, but caused a decrease in the level of Bcl-2. DADS also promoted the activities of caspase-3 leading to DNA fragmentation, thus indicating that DADS-induced apoptosis is caspase-3 dependent. In addition, DADS induced an increase in the level of cytochrome c in the cytoplasm, which was released from mitochondria. BAPTA attenuated the Deltapsim abrogation and significantly diminished the occurrence of DADS-induced apoptosis in Ca Ski cells. In conclusion, DADS-induced apoptosis occurs via production of ROS and caspase-3 and a mitochondria-dependent pathway in Ca Ski cells.

Berberine inhibits WEHI-3 leukemia cells in vivo.

Berberine, an isoquinoline alkaloid, has a wide range of pharmacological effects including anticancer activities, yet the exact effects on leukemia in vivo are unknown. Our previous studies have demonstrated that berberine induced cytotoxicity against murine leukemia WEHI-3 cells in vitro in a dose-dependent manner. In order to understand the berberine action against leukemia, the effect of berberine on WEHI-3 leukemia cells in vivo was studied. The results showed that Mac-3 and CD11b markers were reduced, indicating differentiation inhibition of the macrophages and granulocytes precursors. There was no affect on the CD14 marker but the CD19 marker that was indicating the promotion of the differentiation of the B-cells precursors. The weights of spleen samples from mice treated with berberine were found to be lower when compared to these from untreated animals.

Baicalein induces apoptosis in SCC-4 human tongue cancer cells via a Ca2+-dependent mitochondrial pathway.

BACKGROUND: The effects of baicalein on SCC-4 human tongue cancer cells were examined to better understand its effect on apoptosis and associated possible signal pathways in vitro. MATERIALS AND METHODS: Apoptosis induction, reactive oxygen species (ROS), cytoplasmic Ca2+, mitochondrial membrane potential (MMP) and caspase-3 activity were analyzed using the flow cytometric assay. Apoptosis-associated proteins, such as p53, BAX, BCL-2, cytochrome c, caspase-3 and -9, EndoG and AIF were determined by Western blotting. RESULTS: Our results showed that baicalein promoted the levels of p53, BAX, cytochrome c, capase-3 and -9 and reduced the level of BCL-2, which were associated with the induction of apoptotic cell death of SCC-4 cells. A release of cytochrome c from mitochondria into cytosol was demonstrated and an activation of caspase-3, which led to the occurrence of apoptosis in SCC-4 cells treated with baicalein as determined by Western blot. In order to understand the role of Ca2+ in the induction of apoptosis, cells were pre-treated with BAPTA (intracellular calcium chelator) and baicalein. It was shown that the MMP was restored, and the level of cytoplasmic Ca2+ suppressed, the proportion of cells undergoing apoptosis was also markedly diminished. Our data suggest that cellular Ca2+ modulates baicalein-induced cell death via a Ca2+-dependent mitochondrial death pathway in SCC-4 cells.

(-)-Menthol inhibits WEHI-3 leukemia cells in vitro and in vivo.

(-)-Menthol ([1-alpha]-5-methyl-2-[1-methylethyl]-cyclohexanol), is a widely used flavoring ingredient in mouthwash, foods, toothpaste and cigarettes. The studies reported here revealed that (-)-menthol induced cytotoxicity against murine leukemia WEHI-3 cells in vitro in a dose-dependent manner. The effects of (-)-menthol on WEHI-3 cells in vivo (BALBIc mice) were also examined, and it was observed that the Mac-3 and CD11b markers were decreased, indicating inhibition of differentiation of the precursor of macrophage and granulocyte. The weights of liver and spleen samples from mice treated with (-)-menthol were found to be decreased compared to untreated animals.

Diallyl disulfide induced signal transducer and activator of transcription 1 expression in human colon cancer colo 205 cells using differential display RT-PCR.

Diallyl disulfide is one of the components of garlic and has been demonstrated to induce apoptosis in many cancer cell lines, though it is not reported to be associated with signal transducer and activator of transcription 1 (STAT1) expression. Moreover the role of STAT1 does not directly affect apoptosis in cancer cells after exposure to chemotherapy agents, though some reports showed that STAT1 is associated with apoptosis. In this study, differential display RT-PCR was used to examine the effects of diallyl disulfide (DADS) on human colon cancer cells (colo 205). The results demonstrated that DADS induced the expression of STAT1 which was also confirmed using Western blotting. STAT1 decoy oligonucleotides were also used to block STAT1 mRNA and led to a decrease in the levels of STAT1 and to subsequence decrease in the percentage of apoptosis induced by DADS in examined colo 205 cells.

Curcumin-induced cell cycle arrest and apoptosis in human acute promyelocytic leukemia HL-60 cells via MMP changes and caspase-3 activation.

Curcumin (diferuloylmethane), is a natural product derived from the root of the plant Curcuma longa. For centuries, it has been used as a spice and as a herbal medicine in Chinese populations. Curcumin has been shown to inhibit cell proliferation, cell cycle arrest, cyclooxygenase (COX)-1 and -2 expression and apoptosis in several human cancer cell lines. The aim of this investigation was to clarify the mechanisms by which curcumin induced cytotoxicity and apoptosis in human leukemia HL-60 cells. The effects of curcumin on the levels of reactive oxygen species (ROS), Ca+2 production, cyclin E, cdc25c, wee1, Bcl-2, Bax, the changes of mitochondrial membrane potential (MMP), cytochrome c release and the activation of caspase-3 were also investigated in the HL-60 cells. Results of flow cytometry and DAPI staining assays indicated that curcumin induced cytotoxicity and apoptosis in the examined cells. The results from flow cytometry assay indicated that curcumin induced ROS and Ca+2 productions, decreased the levels of MMP and increased the activity of caspase-3, leading to cell apoptosis. Western blot assay also revealed that curcumin increased the levels of Bax and the release of cytochrome c, and decreased the levels of Bcl-2 in the examined cells. The inhibition of caspase-3 activation by z-VAD-fmk (broad-spectrum caspase inhibitor) completely blocked curcumin-induced apoptosis in HL-60 cells.

Crude extract of garlic induced caspase-3 gene expression leading to apoptosis in human colon cancer cells.

Garlic (Allium sativum) is a popular spice, a remedy for a variety of ailments and is also known for its medicinal uses as an antibiotic, antithrombotic and antineoplastic agent. Epidemiological and animal studies have shown that garlic consumption reduces the incidence of cancer e.g. in the stomach, colon, breast and cervix. The aim of this study was to investigate whether garlic extract has any influence on caspase-3 activity and gene expression and on the signal induction of apoptosis in vitro. As an assay system, the flow cytometry assay, Western blotting and cDNA microarray were applied in human colon cancer colo 205 cells. Our results indicated that garlic extract, when administered to the colo 205 cell cultures, reduced the percetange of viable cells, induced apoptosis, increased the levels of Bax, cytochrome c and caspase-3, but decreased the level of Bcl-2. The results also showed that raw extract of garlic decreased the mitochondrial membrane potential and increased the caspase-3 activity and gene expression. We conclude that crude extract of garlic can induce apoptosis in colo 205 cells through caspase -3 activity, by means of a mitochondrial-dependent mechanism.