Biomedical subjects

T C Hsieh

Publications and source records attributed to T C Hsieh.

At least 19 recordsLinked to original sources

PubMed2002

Combined effects of onconase and IFN-beta on proliferation, macromolecular syntheses and expression of STAT-1 in JCA-1 cancer cells.

Prostate cancer (CaP), the most common malignancy in American men, presents its greatest challenge to clinicians when the cancer progresses to the hormone-refractory state. In the present investigation, we studied the combined effects of interferon (IFN) and onconase, each of which has reported antitumor activity, on growth and specific protein expression in JCA-1 cells. Cells were treated for up to 3 days with 1 and 5 microg/ml onconase, with and without concurrent addition of IFN-beta(ser) (10(3) IU/ml). Cell count and viability, and de novo RNA and protein synthesis were determined. Expression and subcellular distribution of STAT-1 were also assessed by immunoblot analysis. JCA-1 cells treated for 3 days with IFN or onconase showed a 15-30% reduction in cell proliferation, which was increased to 42-51% with both agents. Analysis of [35S]methionine incorporation into cells confirmed a more pronounced inhibitory effect elicited by IFN-beta and onconase; IFN-beta and 1 microg/ml onconase each decreased de novo protein synthesis by 23-25%, while the combination resulted in 59% suppression. Similar studies using incorporation of [3H]uridine into RNA yielded less significant effects. Further investigation using pre-labeled cellular RNA and proteins showed that either agent or their combination did not affect the turnover of macromolecules. To test whether the antiproliferative effects of IFN-beta and onconase were correlated with one or more specific gene changes, expression of an IFN-modulated protein, STAT-1, was determined. Both phosphorylated and unphosphorylated forms of STAT-1 and its subcellular distribution in the nucleus and cytoplasm, were increased 3-fold by IFN-beta. The IFN-elicited elevation of STAT-1 was not additionally augmented by onconase but was reduced 20-25% when onconase was simultaneously present as IFN-beta. These data show that the overall changes in STAT-1 did not correlate with the reduction in cell growth and the suppression of de novo protein/RNA synthesis elicited by these two agents, and imply that other target proteins are likely to be involved in the combined effects of IFN-beta and onconase in JCA-1 cells.

Cell Division↗

PubMed2001

Detection of caspases activation by fluorochrome-labeled inhibitors: Multiparameter analysis by laser scanning cytometry.

BACKGROUND: The fluorochrome-labeled inhibitors of caspases (FLICA) were recently used as markers of activation of these enzymes in live cells during apoptosis (Bedner et al.: Exp Cell Res 259:308-313, 2000). The aims of this study were to (a) explore if FLICA can be used to study intracellular localization of caspases; (b) combine the detection of caspase activation with analysis of the changes with cell morphology detected by microscopy and laser scanning cytometry (LSC); and (c) adapt the assay to fixed cells that would enable correlation, by multiparameter analysis, of caspase activation with the cell attributes that require cell permeabilization in order to be measured. METHODS: Apoptosis of human MCF-7, U-937, or HL-60 cells was induced by camptothecin (CPT) or tumor necrosis factor-alpha (TNF-alpha) combined with cycloheximide (CHX). Binding of FLICA to apoptotic versus nonapoptotic cells was studied in live cells as well as following their fixation and counterstaining of DNA. Intensity of cell labeling with FLICA and DNA-specific fluorochromes was measured by LSC. RESULTS: Exposure of live cells to FLICA led to selective labeling of cells that had morphological changes characteristic of apoptosis. The FLICA labeling withstood cell fixation and permeabilization, which made it possible to stain DNA and measure its content for identification of the cell cycle position of labeled cells. When fixed cells were treated with FLICA, both apoptotic and nonapoptotic cells became strongly labeled and the labeling pattern was consistent with the localization of caspases as reported in the literature. A translocation of the FLICA binding targets from mitochondria to cytosol was seen in the MCF-7 cells treated with CPT. FLICA binding was largely (> 90%) prevented by the substrates of the caspases or by the unlabeled caspase inhibitors having the same peptide moiety as the respective FLICA. CONCLUSIONS: The detection of caspase activation combined with cell permeabilization requires exposure of live cells to FLICA followed by their fixation. Cell reactivity with the respective FLICA, under these conditions, identifies the activated caspases and makes it possible to correlate their activation with the cell cycle position and other cell attributes that can be measured only after cell fixation/permeabilization. FLICA can also be used to study intracellular localization of caspases, including their translocation.

Amino Acid Chloromethyl Ketones↗

PubMed2001

Endoscopic comparison of the gastroduodenal safety and the effects on arachidonic acid products between meloxicam and piroxicam in the treatment of osteoarthritis.

Our objective was to evaluate the efficacy, the gastroduodenal safety, and the effects on arachidonic acid products of meloxicam, a new acidic enolic non-steroidal anti-inflammatory drug which preferentially inhibits cyclo-oxygenase-2 over cyclo-oxygenase-1, versus piroxicam in patients with osteoarthritis of the knee. Meloxicam 7.5 mg or piroxicam 20 mg daily was administered for 4 weeks in this double-blind parallel-groups randomised study. The efficacy for pain relief of the two tested medications was assessed by means of visual analogue scale and other clinical parameters. Pre- and post-treatment endoscopies were performed, and the findings were scored and recorded. The gastric fluid was aspirated at each time and prostaglandin E2, thromboxane B2 and leukotriene B4 were determined by ELISA. There was no significant difference between the groups regarding the primary efficacy. Changes in endoscopic findings by means of Lanza score showed statistically significant differences between the two treatment groups in favour of meloxicam at all sites--gastric, duodenal and total. Within-group comparisons showed a statistically significant difference (worsening) in gastric and total score with piroxicam, but no significant difference with meloxicam. The frequency of clinically relevant cases (total score >2) also showed a statistically significant worsening in the piroxicam group. The better GI tolerability of meloxicam was also suggested by fewer adverse GI events and no withdrawals due to adverse events compared with piroxicam. The pre-/post-study gastric juice concentration of PGE2, TXB2, and LTB4 in the meloxicam group was 135.2 +/- 85.8/71.2 +/- 32.2, 116.3 +/- 81.7/99.4 +/- 107.5 and 388 +/- 321/223 +/- 98 pg/ml respectively. The pre-/post-study gastric juice concentration of PGE2, TXB2 and LTB4 in the piroxicam group was 105.7 +/- 43.1/68.2 +/- 34.9, 94.0 +/- 50.9/105.9 +/- 121.1 and 625 +/- 1574/828 +/- 1464 pg/ml, respectively. Both meloxicam and piroxicam significantly inhibited gastric PGE2 levels after 4 weeks' treatment; however, there was no difference between these two groups. Neither of these medications had an effect on TXB2. Only meloxicam inhibited LTB4 concentration significantly, and the between-groups difference was significant. Meloxicam 7.5 mg once daily had better gastrointestinal tolerability and an efficacy comparable to that of piroxicam 20 mg over 4 weeks in patients with osteoarthritis of the knee.

Adult↗

PubMed2001

Hypoxia activates Akt and induces phosphorylation of GSK-3 in PC12 cells.

Akt is a serine/threonine kinase that has been shown to play a central role in promoting cell survival and opposing apoptosis. We evaluated the effect of hypoxia on Akt in rat pheochromocytoma (PC12) cells. PC12 cells were exposed to varying levels of hypoxia, including 21%, 15%, 10%, 5%, and 1% O(2). Hypoxia dramatically increased phosphorylation of Akt (Ser(473)). This effect peaked after 6 h exposure to hypoxia, but persisted strongly for up to 24 h. Phosphorylation of Akt was paralleled with a progressive increase in phosphorylation of glycogen synthase kinase-3 (GSK-3), one of its downstream substrates. The effect of hypoxia on phosphorylation of Akt was completely blocked by pretreatment of the cells with wortmannin (100 nM), indicating that this effect is mediated by phosphatidylinositol 3-kinase (P13K). In contrast, whereas hypoxia also strongly induced phosphorylation of the transcription factors CREB and EPAS1, these effects persisted in the presence of wortmannin. Thus, hypoxia regulates both P13K-dependent and P13K-independent signaling pathways. Furthermore, activation of the P13K and Akt signaling pathways may be one mechanism by which cells adapt and survive under conditions of hypoxia.

Androstadienes↗

PubMed2001

Mechanism of fenretinide (4-HPR)-induced cell death.

4-HPR (fenretinide) is a synthetic analog of retinoic acid (RA) whose potential as a chemopreventative agent has gained support from in vitro and animal experiments and in limited clinical trials. Comparative analyses of cellular, biochemical, and molecular properties of fenretinide with RA using various tissue culture cells reveal that a key distinction between these two retinoids lies in the ability of fenretinide to induce programmed cell death, also known as apoptosis. Here we review the composite evidence for induction of apoptosis in fenretinide-treated cells. Assays used to validate apoptosis in various cell types are also summarized. Apoptosis in response to fenretinide primarily occurs by a receptor-independent mechanism, which is accompanied by increases in signaling molecules, e.g., ceramide, and cysteine-dependent aspartate-directed proteases, termed caspases, including execution caspase-3. Both caspase-3 inhibitor DEVD-CHO and ceramide synthase inhibitor fumonisin B(1) (FB(1)) block fenretinide-induced apoptosis. Increase in caspase-3 appears to result from fenretinide-elicited stabilization of procaspase-3 zymogen. We also review apoptotic regulatory proteins such as inhibitor of apoptosis (IAPs) and second mitochondria-derived activator of caspase (SMACs) that participate in the coordinate control of caspase activities. The existence of a large number of proteins capable of modulating apoptosis via activation or inhibition of caspases, coupled with the fact that both the initiation and execution phases of apoptosis utilize pre-existing zymogens, which, once set in motion, culminates in an irreversible apoptotic cascade, raise the possibility that the on/off switch of apoptosis is linked to an intricate intracellular regulatory network, capable of responding to external stimuli such as fenretinide. This network functions to provide checks/balances of the need for apoptosis as well as to minimize and prevent untimely errors in apoptosis. We suggest that dynamic and coordinated regulation of apoptosis by such a hypothetical network in vivo may involve co-localization of pro- and anti-apoptotic proteins and their respective activators/inhibitors in a macromolecular modular unit which we propose to be named caspasomes. Fenretinide also induces apoptosis by elevating reactive oxygen species (ROS), unrelated to changes in ceramide-caspases. Thus multiple, distinct pathways contribute to the induction of apoptosis by fenretinide.

Animals↗

PubMed2001

Effects of the flavonoid baicalin and its metabolite baicalein on androgen receptor expression, cell cycle progression and apoptosis of prostate cancer cell lines.

Recent studies on the Chinese herbal medicine PC SPES showed biological activities against prostate cancer in vitro, in vivo and in patients with advanced stages of the disease. In investigating its mode of action, we have isolated a few of the active compounds. Among them, baicalin was the most abundant (about 6%) in the ethanol extract of PC SPES, as determined by HPLC. Baicalin is known to be converted in vivo to baicalein by the cleavage of the glycoside moiety. Therefore, it is useful to compare their activities in vitro. The effects of baicalin and baicalein were studied in androgen-positive and -negative human prostate cancer lines LNCaP and JCA-1, respectively. Inhibition of cell growth by 50% (ED(50)) in LNCaP cells was seen at concentrations of 60.8 +/- 3.2 and 29.8 +/- 2.2 microM baicalin and baicalein, respectively. More potent growth inhibitory effects were observed in androgen-negative JCA-1 cells, for which the ED(50) values for baicalin and baicalein were 46.8 +/- 0.7 and 17.7 +/- 3.4, respectively. Thus, it appears that cell growth inhibition by these flavonoids is independent of androgen receptor status. Both agents (1) caused an apparent accumulation of cells in G(1) at the ED(50) concentration, (2) induced apoptosis at higher concentrations, and (3) decreased expression of the androgen receptor in LNCaP cells.

Antineoplastic Agents, Phytogenic↗

PubMed2001

Antimicrobial susceptibility of Ehrlichia phagocytophila.

Human granulocytic ehrlichiosis is a recently described disease caused by an obligate intracellular gram-negative organism recently named Ehrlichia phagocytophila. To expand our knowledge of the susceptibility of E. phagocytophila, we tested six New York State isolates for susceptibility to 12 antimicrobials using an HL-60 cell culture system. All of the isolates were susceptible to doxycycline (MIC, < or =0.125 microg/ml; minimum bactericidal concentration [MBC], 0.125 to 0.5 microg/ml), rifampin (MIC, < or =0.125 microg/ml; MBC, < or =0.125 microg/ml), ofloxacin (MIC, < or =2 microg/ml; MBC, < or =2 microg/ml), levofloxacin (MIC, < or =1 microg/ml; MBC, < or =1 microg/ml), and trovafloxacin (MIC, < or =0.032 microg/ml; MBC, < or =0.032 microg/ml). Isolates were uniformly resistant to amoxicillin, ceftriaxone, erythromycin, azithromycin, clarithromycin, and amikacin. For one strain, the MBC of chloramphenicol was < or =8 microg/ml. These data suggest that quinolone antibiotics and rifampin may be alternative agents for patients with intolerance to tetracyclines.

Anti-Bacterial Agents↗

PubMed2001

Mechanism of cardioprotection by resveratrol, a phenolic antioxidant present in red wine (Review).

Coronary heart disease (CHD) has been and remains a major contributor to morbidity and mortality in developed countries. The most common form of CHD in the western world is atherosclerosis (AS), especially of the major coronary arteries. Failure to maintain an intact endothelium, as a result of episodic and/or persistent injury and perturbation of the vascular endothelium, promotes formation of fatty streaks which are considered initiation events of AS. Cellular constituents contributing to endothelial injury include endothelial cells, monocytes, platelets, and smooth muscle cells. Individuals diagnosed with AS face complex, enduring clinical complications and enormous medical costs. Simple and easily compliant prevention and treatment measures are therefore strategic considerations in the management of this vascular disease. Based on known risk factors for CHD, priorities in AS prevention should include smoking cessation, blood pressure control, and diet modification. In recent years, the possible benefits of low to moderate consumption of alcoholic beverages, particularly of red wine, in the prevention of heart disease has received increasing attention and debate in the popular media as well as in the scientific community. Such attention has been prompted by research findings supporting a relationship between red wine consumption and the French paradox. This phenomenon refers to people residing in certain parts of France where red wine is customarily consumed during meals having a low CHD mortality, despite living a lifestyle considered to have comparably high CHD risks, as those in the US and many other developed countries. Studies have reported that the cardioprotective effects of red wine are greater than those attributed solely to ethanol and other types of alcoholic beverages. The mechanism(s) underlying the greater CHD protective benefits of red wine have not been elucidated. Recently the polyphenol resveratrol (3,5,4'-trihydroxy-trans-stilbene), known to be abundantly present in red wine, compared to white wine, beer, or spirits, has been demonstrated to elicit a broad spectrum of biological responses in in vitro and in animal studies, including effects that are compatible with the cardioprotective roles proposed for red wine. These recently described effects of resveratrol will be reviewed in this article. We will first summarize published data showing an inverse association between consumption of alcoholic beverages/red wine and risk of CHD. A review of biosynthesis of resveratrol and its presence in food groups and wines will follow. Recent studies relating exposure to wine/resveratrol with reduction in myocardial damage during ischemia-reperfusion, modulation of vascular cell functions, inhibition of LDL oxidation, and suppression of platelet aggregation will be presented. The last section of this review will focus on a discussion of mechanism(s) by which resveratrol acts as a potential cardioprotective agent.

Animals↗

PubMed2001

Cell growth and gene modulatory activities of Yunzhi (Windsor Wunxi) from mushroom Trametes versicolor in androgen-dependent and androgen-insensitive human prostate cancer cells.

The incidence of prostate cancer varies greatly throughout the world; it is highest in African-Americans and lowest in the Asian populations of China, India, and Japan. Geographical differences in both prevalence of latent prostate cancer and mortality have been postulated to be influenced by diverse tumor-promoting and protective factors, both environmental and dietary. Prostate cancer is a tumor with an extremely long latency; the pattern of prostate tumorigenesis, in terms of the display and sequence of appearance of particular molecular or biochemical features, or morphological changes, characterizing different stages of the carcinogenic process, is expected to be heterogeneous. Some insights into tumor heterogeneity and progression can be obtained from studies using cell lines, particularly those derived from different anatomical sites. The present study aims to investigate whether hormone-responsive LNCaP and androgen-refractory JCA-1, PC-3, and DU-145 prostate cancer cells are responsive to Yunzhi (YZ), a proprietary dietary supplement prepared from extracts of Trametes versicolor, also known as Coriolus versicolor (a mushroom consumed by Chinese for its purported health benefits), and to elucidate its mechanism of action. Ethanolic extracts (70%) of YZ significantly reduced LNCaP cell growth, down-regulated the levels of secreted PSA, but had less effects on the expression of intracellular PSA and did not affect levels of the androgen receptor. In androgen-unresponsive prostate cancer cells, YZ had a much less pronounced suppressive effect on proliferation of PC-3 and DU-145 cells, compared to LNCaP, and was inactive against JCA-1 cells. Western blot analyses show that the expression of Rb, a key regulatory protein in G1/S transition, and PCNA, integrally involved in mammalian cell DNA replication, were significantly reduced by treatment with YZ in PC-3 and DU-145 cells, respectively. In contradiction, none of these biochemical parameters were affected in JCA-1 cells under identical treatment conditions. Further analysis shows that YZ increased the levels of signal transducer and activator family of transcription factors STAT 1 and STAT 3 in JCA-1 and not LNCaP cells. The greater sensitivity of LNCaP cells to this polysaccharopeptide raises the possibility that YZ may be considered as an adjuvant therapy in the treatment of hormone responsive prostate cancer; additionally, it may have chemopreventive potential to restrict prostate tumorigenic progression from the hormone-dependent to the hormone-refractory state.

Androgens↗

PubMed2000

Effect of resveratrol on intimal hyperplasia after endothelial denudation in an experimental rabbit model.

The ability of resveratrol to inhibit vascular intimal thickening was tested in an experimental model in which endothelial denudation was performed in the normal rabbit iliac artery. Resveratrol (2 approximately 4mg/ kg/d) was administered intragastrically for 5 weeks beginning 1 week before denudation. At the higher concentration of resveratrol, the intimal hyperplasia of injured vascular wall was effectively inhibited; the intimal proliferation index also was significantly less than that in the untreated control group (0.28 +/- 0.07 vs 0.41 +/- 0.13, respectively, p<0.01); the relative luminal area increased from 0.38 +/- 0.06 in the untreated control group to 0.53 +/- 0.10 in the resveratrol treatment group (p < 0.001); and the count of smooth muscle cells in the thickened intima was statistically significantly reduced in the high dose resveratrol treatment group than that in the untreated group (1,115 +/- 510 vs 1,796 +/- 963, respectively, p < 0.05). Resveratrol added to the culture media of cultured rabbit vascular smooth muscle cells inhibited DNA synthesis in a dose-dependent manner. These results showing that resveratrol is capable of inhibiting intimal hyperplasia of injured artery raise the possibility that this polyphenol might have clinical potential in prevention and treatment of restenosis after angioplasty.

Animals↗

PubMed2000

Fenretinide-induced caspase 3 activity involves increased protein stability in a mechanism distinct from reactive oxygen species elevation.

Fenretinide (4-HPR) is a synthetic retinoid that displays a broad range of biological effects and has also demonstrated clinical efficacy as a chemopreventative agent. One cellular activity of 4-HPR is its ability to induce apoptosis. This effect has been proposed to relate to changes in intracellular reactive oxygen species. We show herein that a 1-h treatment of HL-60 cells with 4-HPR led to a dose-dependent increase in hydroperoxides. Pretreatment of cells with the antioxidant vitamin C abolished apoptosis, measured as the appearance of the sub-G1 peak, in 4-HPR-treated cells. The retinoid also elicited a 3.6-fold increase in caspase 3 activity; however, this increase was not affected by vitamin C treatment. Analysis of caspase 3 protein expression by Western blot analysis revealed that 4-HPR resulted in a significant increase in the appearance of the active p17 subunit without effecting a concomitant change in p32 procaspase 3 levels. Studies on de novo synthesis and stability of caspase 3 by pulse-chase and immunoprecipitation methods show that 4-HPR-treated samples had decreased incorporation of radioactive amino acid precursors into newly synthesized procaspase 3 but, during the chase (for up to 9 h), had more labeled caspase 3 remaining when compared with controls. These studies suggest that 4-HPR may effect changes in caspase 3 activity by modulating changes in zymogen stability by a mechanism distinct from the retinoid-elicited increase in reactive oxygen species.

Acetylcysteine↗

PubMed2000

Specific processing of poly(ADP-ribose) polymerase, accompanied by activation of caspase-3 and elevation/reduction of ceramide/hydrogen peroxide levels, during induction of apoptosis in host HL-60 cells infected by the human granulocytic ehrlichiosis (HGE) agent.

We studied the mechanism by which the human granulocytic ehrlichiosis (HGE) agent induces programmed cell death (apoptosis) in human promyelocytic HL-60 leukemia cells. Using several New York HGE isolates, we show that the HGE agent-elicited apoptosis is accompanied by increased processing of nuclear enzyme poly(ADP-ribose) polymerase (PARP), concurrent with a noticeable increase in caspase 3 activities. A marked increase in the amounts of the signaling molecule ceramide but not of diacylglycerol was also observed in HGE agent-infected HL-60 cells, compared with the amounts in uninfected controls. Simultaneous or prior treatment of infected HL-60 cells with the ceramide synthase inhibitor fumonisin B1 did not affect the magnitude of infection by the intracellular pathogen, as determined by both the presence of morulae and the expression of its outer surface membrane protein, p44. These results suggest that the observed changes in ceramide are generated through the sphingomyelinase pathway and not by way of de novo synthesis of ceramide. We also assayed for changes in intracellular hydrogen peroxide and show that the HGE agent causes a decrease in its concentrations in infected cells.

Apoptosis↗

PubMed1999

Quantification of the human granulocytic ehrlichiosis agent based on analysis of rRNA isolated from control and infected HL-60 cells.

Human granulocytic ehrlichiosis (HGE) is an emerging vector-borne disease caused by an Ehrlichia species similar or identical to E. equi and E. phagocytophila. Previous studies have shown that the pathogen can be cultivated in vitro in permissive cells such as human promyelocytic HL-60 leukemia cells. The mechanism(s) of its infection and propagation in target cells, however, is not well understood, due in part to lack of a method capable of quantitatively determining the amount of the infectious agent. Although several assays currently exist for the HGE agent, they are mostly qualitative and have a number of limitations. In this report, size differences between prokaryotic and eukaryotic rRNAs are utilized to quantitatively assay the HGE agent in HL-60 cells. By comparing the integrated intensity of agarose gel resolved HGE-specific rRNA in host cells, with identically prepared and analyzed rRNA isolated from known quantities of E. coli (JM 109), it is possible to calculate the E. coli-equivalence of the HGE agent present in HL-60 cells according to the equation: Y (E. coli, in viable cells x 10(8)) = -2.573 + 0.11X (% infection by the HGE agent in HL-60 cells). The method described is reproducible, sensitive, and is not limited by availability of antisera. Furthermore, since the assay has no designer primer and repeated amplification requirements, it can be easily disseminated to and standardized in other laboratories.

Cell Count↗

PubMed1999

Resveratrol increases nitric oxide synthase, induces accumulation of p53 and p21(WAF1/CIP1), and suppresses cultured bovine pulmonary artery endothelial cell proliferation by perturbing progression through S and G2.

Epidemiological studies have shown that the regular consumption of red wine may in part account for the apparent compatibility of a high fat diet with a low incidence of coronary atherosclerosis. This phenomenon, commonly referred to as the French paradox, may be associated with red wine constituents that exhibit tumor-preventive properties as well as inhibit reactions that increase the risk of coronary heart disease. Here we show that resveratrol, a polyphenol in red wine, induces nitric oxide synthase, the enzyme responsible for the biosynthesis of NO, in cultured pulmonary artery endothelial cells, suggesting that resveratrol could afford cardioprotection by affecting the expression of nitric oxide synthase. We also show that resveratrol inhibits the proliferation of pulmonary artery endothelial cells, which, based on flow cytometric analysis, correlates with the suppression of cell progression through S and G2 phases of the cell cycle. Western blot analysis and immunocytochemical protein detection combined with multiparameter flow cytometry further demonstrate that the perturbed progression through S and G2 phases is accompanied by an increase in the expression of tumor suppressor gene protein p53 and elevation of the level of cyclin-dependent kinase inhibitor p21(WAF1/CIP1). All of the observed effects of resveratrol, including induction of apoptosis at its higher concentration, are also compatible with its putative chemopreventive and/or antitumor activity.

Animals↗

PubMed1999

Differential effects on growth, cell cycle arrest, and induction of apoptosis by resveratrol in human prostate cancer cell lines.

Epidemiologic studies have suggested that nutrition plays an important role in carcinogenesis and that 30% of cancer morbidity and mortality can potentially be prevented with proper adjustment of diets. Resveratrol, a polyphenol present in red wines and a variety of human foods, has recently been reported to exhibit chemopreventive properties when tested in a mouse skin cancer model system. In this study, we investigated the effects of resveratrol on growth, induction of apoptosis, and modulation of prostate-specific gene expression using cultured prostate cancer cells that mimic the initial (hormone-sensitive) and advanced (hormone-refractory) stages of prostate carcinoma. Androgen-responsive LNCaP and androgen-nonresponsive DU-145, PC-3, and JCA-1 human prostate cancer cells were cultured with different concentrations of resveratrol (2. 5 x 10(-5)-10(-7) M). Cell growth, cell cycle distribution, and apoptosis were determined. Addition of 2.5 x 10(-5) M resveratrol led to a substantial decrease in growth of LNCaP and in PC-3 and DU-145 cells, but only had a modest inhibitory effect on proliferation of JCA-1 cells. Flow cytometric analysis showed resveratrol to partially disrupt G1/S transition in all three androgen-nonresponsive cell lines, but had no effect in the androgen-responsive LNCaP cells. In difference to the androgen-nonresponsive prostate cancer cells however, resveratrol causes a significant percentage of LNCaP cells to undergo apoptosis and significantly lowers both intracellular and secreted prostate-specific antigen (PSA) levels without affecting the expression of the androgen receptor (AR). These results suggest that resveratrol negatively modulates prostate cancer cell growth, by affecting mitogenesis as well as inducing apoptosis, in a prostate cell-type-specific manner. Resveratrol also regulates PSA gene expression by an AR-independent mechanism.

Adenocarcinoma↗

PubMed1999

Resveratrol inhibits copper ion-induced and azo compound-initiated oxidative modification of human low density lipoprotein.

To investigate whether resveratrol, a polyphenolic compound in red wine, affects the oxidation of human low density lipoprotein (LDL), LDL purified from normolipidemic subjects was subjected to Cu(2+)-induce and azo compound-initiated oxidative modification, with and without the addition of varying concentrations of resveratrol. Modification of LDL was assessed by the formation of thiobarbituric acid reactive substances (TBARS) and changes in the relative electrophoretic mobility (REM) of LDL on agarose gels. Resveratrol (50 microM) reduced TBARS and REM of LDL during Cu(2+)-induced oxidation by 70.5% and 42.3%, respectively (p < 0.01), and prolonged the lag phase associated with the oxidative modification of LDL by copper ion or azo compound. These in vitro results suggest that resveratrol may afford protection of LDL against oxidative damage resulting from exposure to various environmental challenges, possibly by acting as a free radical scavenger.

Amidines↗

PubMed1999

Cell cycle effects and control of gene expression by resveratrol in human breast carcinoma cell lines with different metastatic potentials.

Trans-resveratrol, a polyphenol present in red wines and various human foods, is an antioxidant also with reported chemopreventive properties. However, whether resveratrol may exert different effects in malignant cells with a common anatomical origin yet displaying different invasive characteristics is not known. Since invasiveness and metastasis are considered to be the most insidious and life-threatening aspects for all cancers, we compared the ability of resveratrol to control growth and cell cycle transition in the highly invasive MDA-MB-435 with the minimally invasive MCF-7 breast carcinoma cells. The data revealed that resveratrol exerted a greater inhibitory effect on the MDA-MB-435 cells. A diminution of percentage of cells in G1 phase and a corresponding accumulation of cells in S phase of the cell cycle was observed. We also studied the effect of resveratrol on a panel of MDA-MB-435 cells transfected with nm23-H1 and nm23-H2 genes, which have been suggested to play a role in controlling metastasis in breast cancer cells. These cells are designated as Vbeta, 1beta, 1Tbeta, 2beta, and 2Tbeta, respectively. The control Vbeta consists of MDA-MB-435 cells transfected with bacterial beta-glucuronidase. Cells labeled 1beta and 1Tbeta correspond to those carrying beta-glucuronidase and overexpressed wild-type (His118) or mutant (Tyr118, catalytically inactive) nm23-H1 genes. The 2beta and 2Tbeta refer to cells transfected with wild-type and mutant nm23-H2 genes. The responses of these cells to resveratrol were assessed by measuring proliferation, cell cycle phase distribution, and changes in expression of several genes. These studies have shown that resveratrol (25 microM, 3 days) reduced growth of all cell types by 60-80%. Overexpression of both wild-type and catalytically inactive nm23-H1 (1beta, 1Tbeta) but not nm23-H2 (2beta, 2Tbeta) reduced the proportion of cells in G1 phase, compared to the Vbeta control cells. Little changes in expression of PCNA, Rb, p53, and bcl-2 were observed in the five cell types treated with resveratrol, compared to untreated cells. Noted exceptions included reduced expression of Rb protein and increased expression of p53 in 2beta and 2Tbeta cells, and increased expression of bcl-2 in 2beta cells, treated with resveratrol. In contrast, resveratrol upregulated expression of cathepsin D by 50-100% in all cell lines except 1beta. These results suggest that the intrinsic metastatic potential of cancer cells may affect their responses to chemopreventive agents such as resveratrol.

Adenocarcinoma↗

PubMed1999

Suppression of mitogenesis and regulation of cell cycle traverse by resveratrol in cultured smooth muscle cells.

Resveratrol (3,5,4'-trihydroxystilbene), a natural product derived from grapes, has been reported to exert a plethora of biological functions. Recent studies suggest that resveratrol could act as a cardioprotective agent by controlling the oxidation of low density lipoproteins, as well as the proliferation of endothelial cells. Since migration and proliferation of smooth muscle cells (SMCs) in the intima of susceptible vessels is also widely accepted as a requisite for atherogenesis, we investigated the effects of resveratrol on proliferation and cell cycle control of cultured smooth muscle cells. Results of these experiments are reported herein. Resveratrol reduces SMC proliferation in a dose-dependent manner, with 50-100 microM resveratrol resulting in 70-90% reduction of SMC proliferation induced by such diverse mitogens as serum, endothelin and PDGF. The anti-mitogenic effects of resveratrol are not mediated by the induction of apoptosis, but appear to relate to a G1-->S block in cell cycle traverse. These results give further support to the hypothesis that resveratrol holds promise as an anti-atherosclerotic agent.

Animals↗