Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
Citations
To evaluate the effect of X-ray irradiation on apoptosis and change of expression of aquaporin 5 (AQP5) and transforming growth factor-β(TGF-β) in the rat submandibular gland (SMG).
SMGs of 120 male Sprague-Dawley rats were irradiated with a single X-ray dose (3, 10, 20, or 30 Gy). At the early and late post-irradiation phase, apoptosis was measured by the terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) method, and expression of AQP5 and TGF-β was determined by immunohistochemical staining.
At the late post-irradiation phase, increased apoptosis was evident and marked decreases of expression of AQP5 expression by acinar cells and TGF-β expression by ductal cells were evident.
Apoptosis after X-ray irradiation develops relatively late in rat SMG. Irradiation reduces AQP5 and TGF-β expression in different SMG cell types.
Citations
Malignant astrocytomas are among the commonest primary brain tumors and they have a grave prognosis, and so there is an urgent need to develop effective treatment. In this study, we investigated the molecular mechanisms that are responsible for the anti-tumor effect of ginsenosides on human astrocytoma cells.
We tested 13 different ginsenosides for their anti-tumor effect on human malignant astrocytoma cells in conjunction with Fas stimulation. In addition, the cell signaling pathways were explored by using pharmacological inhibitors and performing immunoblot analysis. DCF-DA staining and antioxidant experiments were performed to investigate the role of reactive oxygen species as one of the apoptosis-inducing mechanisms.
Among the 13 different ginsenoside metabolites, compound K and Rh2 induced apoptotic cell death of the astrocytoma cells in a caspase- and p38 MAPK-dependent manner, yet the same treatment had no cytotoxic effect on the primary cultured human astrocytes. Combined treatment with ginsenosides and Fas ligand showed a synergistic cytotoxic effect, which was mediated by the reduction of intracellular reactive oxygen species.
These results suggest that ginsenoside metabolites in combination with Fas ligand may provide a new strategy to treat malignant astrocytomas, which are tumors that are quite resistant to conventional anti-cancer treatment.
Citations
Recent studies have shown that Dickkopf-1 (DKK-1) is overexpressed in some tumors, including hepatocellular carcinoma. However, the role of increased DKK-1 in these tumors is not known. In this study, the DKK-1 expression in hepatocellular carcinoma (HCC) cell lines was evaluated and the effect of DKK-1 overexpression in HCC cell lines was studied.
The expression of DKK-1 in hepatocellular carcinoma cell lines was evaluated by RT-PCR. Stable cell lines that overexpressed DKK-1 were established. Cell growth, adhesion, migration and invasion assays were performed.
RT-PCR analysis showed that 5 out of 8 HCC cell lines expressed DKK-1. The forced expression of DKK-1 suppressed the growth of cells and increased the population of cells in the sub-G1 phase. In addition, DKK-1 reduced the cellular adhesion capacity to collagen type I and fibronectin, and it increased migratory capacity. However, overexpression of DKK-1 did not increase the invasion capacity of the HCC cell line.
Collectively, our data suggest that overexpression of DKK-1 affects the biology of HCC cells.
Citations
The tumor suppressor gene, p53, has been established as an essential component for the suppression of tumor cell growth. In this study, we investigated the time-course anticancer effects of adenoviral p53 (Adp53) infection on human ovarian cancer cells to provide insight into the molecular-level understanding of the growth suppression mechanisms involved in Adp53-mediated apoptosis and cell cycle arrest.
Three human cervical cancer cell lines (SiHa, CaSki, HeLa and HT3) were used. The effect of Adp53 infection was studied via cell count assay, cell cycle analysis, FACS, Western blot and macroarray assay.
Adp53 exerts a significant role in suppressing cervical cancer cell growth. Adp53 also showed growth inhibitory effects in each cell line, and it induced apoptosis and cell cycle arrest. Adp53 differentially regulated the expression of genes and proteins, and the gene expression profiles in the SiHa cells revealed that the p21, p53 and mdm2 expres sions were significantly up-regulated at 24 and 48 hr. Western blot shows that the p21 and p53 expression-levels were significantly increased after Adp53 infection. In addition, in all cell lines, both the CDK4 and PCNA protein expression levels were decreased 48 h after Adp53 infection. Cell cycle arrest at the G1 phase was induced only in the SiHa and HeLa cells, suggesting that exogenous infection of Adp53 in cancer cells was significantly different from the other HPV-associated cervical cancer cells.
Adp53 can inhibit cervical cancer cell growth through induction of apoptosis and cell cycle arrest, as well as through the regulation of the cell cycle-related proteins. The Adp53-mediated apoptosis can be employed as an advanced strategy for developing preferential tumor cell-specific delivery.
Citations
Sodium butyrate (NaBT) is principally a histone deacetylase (HDAC) inhibitor, and it has the potential to arrest HPV-positive carcinoma cells at the G1 to S phase transition of the cell cycle. The aim of study was to determine whether phosphatidylinositol 3-kinase (PI3K) inhibition can enhance the inhibitory effect of NaBT on a human cervical cancer cell line (HeLa).
Cervical cancer cells (HeLa) were treated with NaBT alone or in combination with the PI3K inhibitors wortmannin or LY294002. Cell viability analysis and FACS analysis were carried out. The expressions of the cell cycle related proteins were evaluated by Western-blot analysis.
Inhibition of PI3K enhanced NaBT-mediated apoptosis and this decreased the HeLa cell viability. Either wortmannin or LY294002, combined with NaBT, enhanced the activation of caspase 3 and caspase 9, and this enhanced the subsequent cleavage of poly (ADP-ribose) polymerase (PARP). Cervical cancer cells were arrested in the subG1 and G2/M phase, as was detected by FACS analysis. NaBT treatment in combination with PI3K inhibitors showed the increased expression of the CDK inhibitors p21Cip1/Waf1 and p27Kip1, in a p53 dependent manner, and also the increased dephosphorylation of Rb whereas there was a reduction in the expression levels of cyclin A, cyclin D1 and cyclin B1.
The results demonstrate that inhibition of PI3K enhances NaBT-mediated cervical cancer cell apoptosis through the activation of the caspase pathway. Moreover, these findings will support future investigation using the PI3K inhibitors in combination with adjuvant treatment for treating carcinoma of the cervix.
Citations
Treatment with arsenic trioxide (As2O3) results in a wide range of cellular effects that includes induction of apoptosis, inhibition of cell growth, promotion or inhibition of cellular differentiation, and inhibition of angiogenesis through a variety of mechanisms. The mechanisms of As2O3-induced cell death have been mainly studied in hematological cancers, and those mechanisms in solid cancers have yet to be clearly defined. In this study, the mechanisms by which As2O3 induces apoptosis in human colorectal adenocarcinoma HT-29 cells were investigated.
To examine the levels of apoptosis, HT-29 cells were treated with As2O3 and then we measured the percentage of Annexin V binding cells, the amount of ROS production and the mitochondrial membrane potential. Western blot analysis was performed to identify the activated caspases after As2O3 exposure, and we compared the possible target molecules of apoptosis. As2O3 treatment induced the loss of the mitochondrial membrane potential and an increase of ROS, as well as activation of caspase-3, -7, -9 and -10.
As2O3 induced apoptosis via the production of reactive oxygen species and the loss of the mitochondrial membrane potential. As2O3 induced the activation of caspase-3, -7, -9 and -10. Furthermore, As2O3 treatment downregulates the Mcl-1 and Bcl-2 expressions, and the release of cytochrome c and an apoptosis-inducing factor (AIF). Pretreating the HT-29 cells with
Taken together, these results suggest that the generation of reactive oxygen species (ROS) by As2O3 might play an important role in the regulation of As2O3-induced apoptosis. This cytotoxicity is mediated through a mitochondria-dependent apoptotic signal pathway in HT-29 cells.
Citations
Resveratrol is a phenolic compound found in grapes and other food products. In order to assess the availability of resveratrol as an angio-inhibiting drug, we examined whether resveratrol plays an important role in bovine aortic endothelial cells (BAECs) for cell apoptosis and cell migration.
Endothelial cell apoptosis was observed as detected by the Hoechst staining and the caspase-3 activity. Additionally, Western blotting was performed for monitoring the activities of various cell signaling molecules.
Resveratrol was shown to act as a pro-apoptotic agent. The pro-apoptotic effect of resveratrol was as great as that of etoposide, a well-known anti-cancer drug. In addition, resveratrol had an inhibitory effect on endothelial cell migration. The demonstrated efficacy of resveratrol suggests that resveratrol may be utilized as an anti-angiogenic drug. To determine the underlying mechanisms, we further investigated which signaling molecules are activated by resveratrol. Extracellular signal-regulated kinase (ERK) was activated by the treatment with resveratrol in BAECs, whereas endothelial nitric oxide synthetase (eNOS), Akt, and Jun N-terminal kinase (JNK) were inhibited. The pretreatment with PD compound, an ERK inhibitor, had no effect on the pro-apoptosis induced by resveratrol.
Resveratrol plays an important role in endothelial cell apoptosis, indicating that resveratrol can be utilized as a potent anti-angiogenic drug.
Citations
NS398, a selective COX-2 inhibitor, is known to inhibit the growth of COX-2 expressing hepatocellular carcinoma cells. The present study investigated whether the cytotoxic effect of NS398 was COX-2 dependent and whether caspases were involved in NS398-induced apoptosis in hepatocellular carcinoma cells.
The expressions of COX-2 in SNU 423 and SNU 449 hepatocellular carcinoma cell lines were examined using RT-PCR and Western blot. The cytotoxic effect of NS398 was measured using MTT in the presence or absence of caspase inhibitors. The distribution of the cell cycle and extent of apoptosis were analyzed using flow cytometry and a Cell Death Elisa kit, respectively.
The expression of COX-2 was observed in SNU423 cells, but not in SNU 449 cells. NS398 treatment resulted in both dose-and time-dependent growth inhibitions, with increases in apoptotic cells in both cell lines. Treatment with the pan-caspase inhibitor, z-VAD- fmk, or the caspase-3 inhibitor, Ac-DMQD-CHO, showed no attenuation of the cytotoxic effect of NS398 in either cell line.
This study demonstrated that the cytotoxic effect of NS398 was independent of COX-2 expression. Caspases were also shown not to be involved in NS398-induced apoptosis in either SNU 423 or SNU 449 Korean HCC cell lines. Our data suggests the feasibility of preventing hepatocellular carcinoma with the use of COX-2 inhibitors needs to be carefully evaluated.
Citations
It is well known that infection with HPV (human papillomavirus) is the main cause of cervical cancer and certain types of HPV are recognized as carcinogens. At present, there is little information regarding the antineoplastic mechanism of paclitaxel against cervical carcinoma cells. We thus tried to analyze differential protein expression and antineoplastic mechanism-related proteins after paclitaxel treatment on cervical cancer cells by using a proteomic analysis and to investigate the mechanism of action.
Using proteomics analysis including 2-DE and MALDI-TOF-MS, we detected the antineoplastic mechanism-related proteins. Then, we performed western blot analysis for apoptosis- and transformation-related proteins to confirm expression patterns derived from proteome analysis after paclitaxel treatment.
We identified several cellular proteins that are responsive to paclitaxel treatment in HeLa cells using proteomics methods. Paclitaxel treatment elevated mainly apoptosis, immune response and cell cycle check point-related proteins. On the other hand, paclitaxel treatment diminished growth factor/oncogene-related proteins and transcription regulation-related proteins. Also, in the HPV-associated cervical carcinoma cells, paclitaxel demonstrated anti-proliferative activity through the membrane death receptor-mediated apoptotic pathway and the mitochondrial-mediated pathway.
Identification and characterization of functionally modulated proteins involved in anti-cancer regulatory events should lead to a better understanding of the long-term actions of paclitaxel at the molecular level and will contribute to the future development of novel therapeutic drug treatments based upon current therapies.
Citations
Phenylacetate has potent antiproliferative effects in many malignant tumors. However, the exact mechanism as to how phenylacetate induces cell growth arrest remains unclear and very little is known about its effects on human osteosarcoma cells. In this study, we investigated whether phenylacetate is effective against two osteosarcoma cell lines (HOS and U-2 OS)
The viability of phenylacetate-treated cell lines was assessed by trypan blue exclusion assay, and the cell cycle distribution was measured by flow cytometry. To measure cell apoptosis, poly (ADP-ribose) polymerase cleavage assay and flow cytometry were employed. The expressions of cell cycle-regulatory proteins and the apoptosis-related genes were evaluated by western blot analysis.
Phenylacetate was found to inhibit the growth of osteosarcoma cells, induce cell cycle arrest in the G1 phase, and induce apoptosis. A significant decrease in Bcl-2 expression and a mild up-regulation of Bax were also observed in both phenylacetate-treated cell lines. Reduced phosphorylation of the pRb and the increased expression of p21Cip1 were observed subsequent to treatment with phenylacetate.
These findings support the idea that phenylacetate may be an effective chemotherapeutic agent to be employed in the future against osteosarcoma, because phenylacetate acts to inhibit the growth of osteosarcoma cells through cell cycle arrest and apoptosis.
Citations
A constituent of green tea, (-)-epigallocatechin-3-gallate (EGCG), is known to possess anti-cancer properties. In this study, the time-course of the anticancer effects of EGCG on human ovarian cancer cells were investigated to provide insights into the molecular-level understanding of the growth suppression mechanism involved in EGCG-mediated apoptosis and cell cycle arrest.
Three human ovarian cancer cell lines (p53 negative, SKOV-3 cells; mutant type p53, OVCAR-3 cells; and wild type p53, PA-1 cells) were used. The effect of EGCG treatment was studied via a cell count assay, cell cycle analysis, FACS, Western blot and macroarray assay.
EGCG exerts a significant role in suppressing ovarian cancer cell growth, showed dose dependent growth inhibitory effects in each cell line and induced apoptosis and cell cycle arrest. The cell cycle was arrested at the G1 phase by EGCG in SKOV-3 and OVCAR-3 cells.
In contrast, the cell cycle was arrested in the G1/S phase in PA-1 cells. EGCG differentially regulated the expression of genes and proteins (Bax, p21, Retinoblastoma, cyclin D1, CDK4 and Bcl-XL) more than 2 fold, showing a possible gene regulatory role for EGCG. The continual expression in p21WAF1 suggests that EGCG acts in the same way with p53 proteins to facilitate apoptosis after EGCG treatment. Bax, PCNA and Bcl-X are also important in EGCG-mediated apoptosis. In contrast, CDK4 and Rb are not important in ovarian cancer cell growth inhibition.
EGCG can inhibit ovarian cancer cell growth through the induction of apoptosis and cell cycle arrest, as well as in the regulation of cell cycle related proteins. Therefore, EGCG-mediated apoptosis could be applied to an advanced strategy in the development of a potential drug against ovarian cancer.
Citations
The Potential Roles of Epigallocatechin-3-Gallate in the Treatment of Ovarian Cancer: Current State of Knowledge
This study was conducted to explore whether CDCA derivatives induce apoptosis in a stomach cancer cell line, and to dissect the detailed mechanism underlying apoptosis.
The human stomach cancer cell line, SNU-1, cells were treated with the synthetic CDCA derivatives, HS-1199 and HS-1200. DNA and mitochondrial stains were used to detect apoptotic cells by fluorescence imaging or flow cytometry. The caspase-3 activity was measured by Western blotting.
Both the HS-1199 and HS-1200 induced decreased viabilities of the SNU-1 cells, in time-dependent manners. The CDCA derivatives demonstrated various apoptosis hallmarks, such as mitochondrial changes (reduction of MMP, cytochrome c release, and Smac/ DIABLO translocation), activation of caspase-3 (resulting in the degradation of PARP and DFF45), DNA fragmentation and nuclear condensation.
The CDCA derivatives, HS-1199 and HS-1200, both induced apoptosis of the SNU-1 gastric cancer cells in caspase- and mitochondria-dependent fashions. Many important issues relating to their therapeutic applications remain to be elucidated.
Citations