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Biomedical subjects

T C Hsieh

Publications and source records attributed to T C Hsieh.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1999

Development of human prostate cancer cells to neuroendocrine-like cells by interleukin-1.

Growth and development of some prostate epithelial cells are androgen-dependent. Non-androgenic hormones and growth factors may also influence prostate cells and the effect of interleukin 1beta (IL-1beta) has been investigated with an androgen-dependent human prostate cancer cell line LNCaP. Exposure of LNCaP cells to IL-1beta at picomole ranges resulted in a dose-dependent and progressive differentiation to neuroendocrine-like cells evidenced by dendrite formation and the development of specific neuroendocrine cell markers. Quantification by computer-based image analysis after immunostaining revealed a two-fold increase of chromogranin A in 90% of the cells and a ten-fold increase in the remaining 10%. Additionally, serotonin was developed in all the cells with the staining intensity increased by five-fold. Significant increase in cytokeratin 8 and reduction of prostate specific antigen was also noted. Proliferation was reduced in parallel to the cellular development. The IL-1beta effect was irreversible after several days of IL-1beta incubation. IL-1beta is produced constitutively and its secreted level has an inversed relation during the exponential and plateau phases of cell growth. An IL-1 autocrine regulation in the growth and differentiation of prostate cells is discussed.

Biomarkers↗
PubMed1999

Clinical and laboratory evolution of a culture-confirmed case of human granulocytic ehrlichiosis.

A 74-year-old man from suburban New York City, who was hospitalized because of chest pain and fever, was diagnosed as having human granulocytic ehrlichiosis on the eighth hospital day. Although leukocyte and platelet counts were normal on admission, they fell to abnormally low values then normalized prior to specific therapy against the human granulocytic ehrlichiosis agent. Intracytoplasmic inclusions suggestive of Ehrlichia were observed in up to six percent of granulocytes, and the human granulocytic ehrlichiosis bacterium was cultured in an HL 60 human promyelocytic cell line. The patient improved dramatically within 24 hours of doxycycline treatment, after failing to improve on various beta lactam antimicrobial agents. He was discharged from the hospital 14 days after admission. Because human granulocytic ehrlichiosis was not diagnosed until his eight hospital day, clinical and laboratory parameters prior to specific treatment were available. This case illustrates the clinical and laboratory evolution of the infection with human granulocytic ehrlichiosis agent in humans.

Aged↗
PubMed1998

Regulation of G1/S transition and induction of apoptosis in HL-60 leukemia cells by fenretinide (4HPR).

We previously reported that all-trans retinoic acid (RA) and fenretinide (4HPR) suppress HL-60 leukemia cell growth and cause partial cell arrest in the G1-to-S phase. Moreover, 4HPR but not RA induces apoptosis in HL-60 cells. To investigate further the observed biological effects, cyclin D1 and cdk4 expression and the level of phosphorylation of the retinoblastoma protein Rb were assessed. Cyclin D1 and cdk4 expression and Rb phosphorylation were significantly reduced, by 40-75%, after 24 hr of treatment with RA or 4HPR; these decreases were either transient, e.g., only at 24 hr for cdk4, or sustained for 72 hr. In general, more pronounced decreases were seen in the 4HPR-treated cells. Evidence for 4HPR-induced apoptosis comes from (1) cleavage of the enzyme poly(ADP-ribose) polymerase (PARP) to an 89-kDa truncated product, (2) appearance of DNA ladders on agarose gel electrophoresis, and (3) higher incorporation in situ of digoxigenin nucleotides into the free 3'-ends of DNA. Overnight pretreatment with 0.5-5.0 microM of the CPP32 inhibitor DEVD, but not the ICE inhibitor YVAD, significantly reduced the specific processing of PARP, suggesting that CPP32 is involved in the mechanism of action of 4HPR. Analysis of 2 lipid-derived second messengers, ceramide and diacylglycerol (DAG), as a function of time of treatment with RA or 4HPR, showed ceramide but not DAG to be significantly albeit transiently increased 2-fold at 3 hr, by 4HPR. To test further whether ceramide may be involved in the signaling cascade that culminates in the induction of apoptosis in 4HPR-treated HL-60 cells, the effects of fumonisin B1, an inhibitor of ceramide synthase, were studied. Simultaneous treatment of cells with 4HPR and 25-100 microM fumonisin B1 resulted in a dose-dependent reduction in the elevation in ceramide, the extent of PARP cleavage, and induction of apoptosis. Pretreatment with DEVD or YVAD, on the other hand, had no effect on the 4HPR-induced increase in ceramide.

Anticarcinogenic Agents↗
PubMed1998

Cell cycle effects and induction of apoptosis caused by infection of HL-60 cells with human granulocytic ehrlichiosis pathogen measured by flow and laser scanning cytometry.

Human granulocytic ehrlichiosis (HGE) is an occasionally severe and even fatal disease caused by an agent closely related to Ehrlichia equi and Ehrlichia phagocytophila, which is transmitted by ticks. Little is known about the pathogen itself, which only very recently has been isolated. The agent can be cultivated in vitro because it replicates in human promyelocytic leukemic HL-60 cells. Using multiparameter flow cytometry and laser scanning cytometry (LSC) we have investigated changes in HL-60 cells following their infection with the pathogen. Its presence within the infected HL-60 cells was detected and its intracellular level measured inmmunocytochemically using antibodies obtained from HGE-infected patients. The percentage of the infected cells measured by flow cytometry or LSC correlated well with the estimates by microscopy on the Giemsa-stained specimens. In the infected cultures, the cells had diminished levels of cyclins D3 and E as well as the cyclin dependent kinase inhibitor p21WAF1/CIP1 and were arrested predominantly in G0/1. The apoptosis-associated regulatory proteins were also affected by cell infection: expression of Bcl-2 was decreased in the infected cells whereas expression of Bax become more variable, with some cells showing higher levels of this protein. The infected cells developed numerous DNA strand breaks characteristic of apoptosis. The presence of the pathogen was also detected by LSC in cells from peripheral blood of the infected patients; after relocation and visual inspection ("CompuSort") the pathogen-positive cells were identified as leukocytes. This unique ability of LSC to detect, quantify, and visualize HGE in infected cells made this instrument particularly useful to measure the degree of infection in peripheral blood of the patients and study effects of the infectious agent on the cell cycle and apoptosis of the host cells.

Apoptosis↗
PubMed1998

Clinical and laboratory spectrum of culture-proven human granulocytic ehrlichiosis: comparison with culture-negative cases.

We describe the clinical and laboratory manifestations of human granulocytic ehrlichiosis (HGE) in eight patients for whom cultures were positive for the HGE agent and compare them with 15 patients for whom cultures were negative but who fulfilled a modified New York State Surveillance definition for HGE. Polymerase chain reaction analysis was positive in 8 (100%) of 8 culture-positive cases vs. 3 (20%) of 15 culture-negative cases (P < .001), morulae were detected in 7 (100%) of 7 culture-positive cases in which tests were performed vs. 0 of 15 culture-negative cases (P < .001), and a fourfold change in antibody titer was demonstrated in 6 (75%) of 8 culture-positive cases vs. 9 (69%) of 13 culture-negative cases (P = not significant). Patients for whom cultures were positive had higher mean oral temperatures +/- SD at presentation than did patients for whom cultures were negative (38.6 degrees C +/- 0.7 degree C vs. 37.2 degrees C +/- 0.8 degree C, respectively; P = .002). Other symptoms and signs were not significantly different between the two groups. Multivariate analysis revealed that the lymphocyte count at presentation was significantly lower in culture-positive cases than in culture-negative cases. Clinical response to treatment was similar in the two groups. Culture confirmation of HGE is the gold standard for defining the sensitivity and specificity of other diagnostic tests presently being developed.

Adult↗
PubMed1998

Induction of apoptosis and down-regulation of bcl-6 in mutu I cells treated with ethanolic extracts of the Chinese herbal supplement PC-SPES.

PC-SPES, an HPLC-standardized 8-herb dietary supplement prepared by proprietary extraction/mixing technologies, appears to have a number of health benefits when given to cancer patients. These include reduction of serum PSA (prostate specific antigen) in individuals diagnosed with advanced prostate carcinoma, and overall improvement of morbidity and immune status in terminal cancer cases. Since the expression of bcl-6 in T and B lymphocytes has been reported to be significantly down regulated by mitogens, we reason that the immune boosting effects of PC-SPES could involve the modulation of bcl-6 expression. Such a hypothesis was tested in the bcl-6 abundant Mutu I cells. Specifically, we investigated the effects of PC-SPES in regulating cell growth, induction of apoptosis, effecting changes in the retinoblastoma gene RB and the modulation of expression of the bcl-6. Herein we report that proliferation of Mutu I cells was inhibited by a 3-7 day incubation with ethanolic extracts of PC-SPES, with concurrent induction of apoptosis. In addition, a dose-dependent reduction of bcl-6 was observed, with no concomitant change in either the phosphorylated or the unphosphorylated forms of RB. These data raise the possibility that PC-SPES may enhance immune functions in vivo by down-regulating bcl-6 expression. Alternatively, decrease in bcl-6 could serve as a biomarker for testing the efficaciousness of PC-SPES in vivo.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Effects of fenretinide (4-HPR) on prostate LNCaP cell growth, apoptosis, and prostate-specific gene expression.

BACKGROUND: Although fenretinide (4-HPR) is currently being evaluated in a phase II clinical study for the chemoprevention of prostate cancer [Greenwald et al.: CA 45:31-49, 1995], the mechanism underlying its antineoplastic activity has not been elucidated. METHODS: Androgen-dependent human prostatic LNCaP cells cultured with fetal bovine serum (FBS) were treated with 4-HPR and evaluated for effects on cell growth and cell cycle phase distribution, induction of apoptosis, and changes in proliferating cell nuclear antigen (PCNA), prostate-specific antigen (PSA), and androgen receptor (AR) levels. RESULTS: LNCaP cells treated with 4-HPR for 6 days showed 82-95% suppression of cell growth, with accompanying time- and dose-dependent downregulation of PCNA, a partial arrest in G1 phase of the cell cycle, and a marked increase in the percentage of apoptotic cells. Apoptosis was demonstrated by the characteristic DNA fragmentation pattern seen on agarose gels, and by flow cytometric analysis. 4-HPR-induced prostate-specific phenotype changes included significant downregulated expression of both intracellular and secreted forms of PSA, which were preceded by a reduction of AR expression. CONCLUSIONS: These data suggest that 4-HPR acts as a pleiotropic effector of prostate cell growth and specific gene expression.

Animals↗
PubMed1997

Cellular changes and induction of apoptosis in human promyelocytic HL-60 cells infected with the agent of human granulocytic ehrlichiosis (HGE).

Human granulocytic ehrlichiosis (HGE) is an emerging and occasionally fatal human infectious disease whose pathogenesis is largely unknown. Goodman et al. (1) recently described the successful cultivation of the HGE infectious agent in human promyelocytic HL-60 leukemic cells. It was reported in the same study that infectivity invariably led to host cell death, although the mechanism by which HGE infection triggers cellular self-destruction is as yet undetermined. In this communication, we show that in vitro passage of HGE pathogen-infected blood elicits a significantly dysfunctional G1-to-S transition. Moreover, we provide evidence that the cytopathic properties of the HGE pathogen are attributed to its ability to induce apoptosis in host HL-60 cells. Determination of specific protein expression changes by Western blot analysis showed that HGE infection resulted in reduced expression of PCNA and pRB, both of which play a role in cell cycling. Moreover, the steady state level of bcl-2, which protects eukaryotic cells against apoptosis, is suppressed by exposure to the HGE agent. These results suggest that this pathogen HGE induces apoptosis in HL-60 cells by a mechanism involving the shut-off of multiple cell cycle and apoptosis regulatory events.

Apoptosis↗
PubMed1996

Differential effects of retinoic acid (RA) and N-(4-hydroxyphenyl) retinamide (4-HPR) on cell growth, induction of differentiation, and changes in p34cdc2, Bcl-2, and actin expression in the human promyelocytic HL-60 leukemic cells.

Incubation of the HL-60 cells with 3 microM of RA and 4-HPR resulted in suppression of cell growth and decrease in cell viability. A significant percentage of the RA-treated cells also displayed differentiation towards neutrophils, as assayed by changes in nitroblue tetrazolium reduction (NBT) and alpha-naphthyl-acetate esterase (ANAE) activities, whereas the 4-HPR treated cells remained essentially undifferentiated. Flow cytometric analysis showed 4-HPR to cause partial cell arrest in the G2/M phase after a 3-day treatment and an additional G1 phase arrest after a 7-day treatment. With RA-treated cells, a reduction in the percentage of cells in the G1 phase was observed after 7 days of treatment. In 4-HPR-treated cells an extra peak, characteristic of cells undergoing apoptosis, was found in the cell cycle phase distribution analysis. Determination of specific protein expression changes by Western blot analysis showed that the p34cdc2 was down-regulated by both chemicals. Furthermore, RA induced bcl-2 but prevented the processing of actin, whereas 4-HPR had little effect on bcl-2 but increased the specific processing of actin. These results suggest that RA promotes neutrophil differentiation and the establishment of a semi apoptosis-resistant state, possibly through the overexpression of the bcl-2 gene. By contrast, 4-HPR may trigger apoptosis by inducing overall cyto-architectural changes and specific DNA fragmentation subsequent to increased turnover of the protein actin.

Actins↗
PubMed1996

Effects of IFN-beta and 1,25-dihydroxyvitamin D3 on cellular proliferation, induction of 2',5'-oligoadenylate (2-5A) synthetase and changes in immunoreactive pRB/p53 in human prostatic JCA-1 cells.

The combined antimitogenic effects of IFN-beta and 1,25-dihydroxyvitamin D3 (vit. D3) were investigated by treating the androgen-independent JCA-1 cells, established from the primary prostatic tumor site prior to anti-hormonal therapy, with IFN-beta (1000 IU/ml), vit. D3 (100 nM), and both agents. Cell growth, changes in overall RNA and protein contents, and cell cycle regulatory proteins pRB/p53 were determined. After a 24 h exposure, a significant reduction in cell proliferation was observed in all three conditions. IFN-beta, vit D3, and their combination elicited, respectively, a 1.7-, 1.6- and 2.5-fold increase in total RNA and a corresponding 1.4-, 1.2- and 1.7-fold increase in soluble proteins. The IFN-inducible 2-5A synthetase activity was elevated by 15-, 1.4- and 21-fold, respectively. No differences in cell cycle phase distribution were found between control and treated samples. However, a significant change in pRB and p53 expression was observed upon exposure to these agents. A progressive increase in total pRB was observed in untreated JCA-1 cells, with the 48 h culture showing a 1.9-fold increase over the 6 h culture. The ratio of phosphorylated to the nonphosphorylated forms of pRB, however, decreased from 3.00 at 6 h to 1.2 at 48 h. The overall pRB increase as well as the modified:unmodified protein ratio change were both markedly decreased when the cells were treated with IFN-beta, vit. D3, or their combination. With p53, a similar progressive increase was also observed in control cells, which was largely abolished by IFN-beta but only partially blocked by vit. D3. The combination of IFN-beta and vit. D3 gave results similar to samples receiving vit. D3 alone suggesting that the effects of IFN-beta, insofar as p53 modulation is concerned, is distal to the effects of vit. D3.

2',5'-Oligoadenylate Synthetase↗
PubMed1996

Phosphorylation of native and truncated isoforms of protein tau by the double-stranded DNA-dependent protein kinase (DNA-PK) shows that the primary phosphorylation sites are localized between amino acid residues 212-231 of the longest tau.

Alzheimer's disease (AD) is pathologically characterized by the appearance of neurofibrillary tangles (NFT), senile plaques, and loss of subpopulation of neuronal cells. The NFT is composed of paired helical filaments (PHT) with extensively modified protein T as its primary constituent. Previously we had reported on the hyperphosphorylation of T by a double-stranded-DNA-stimulated protein kinase (DNA-PK). In this communication, we have compared the DNA-PK mediated phosphorylation of native and truncated TS with that catalyzed by the cAMP-dependent protein kinase (PKA). In addition, we have attempted to map the primary site(s) of phosphorylation of T by DNA-PK. Our results suggest that DNA-PK phosphorylates T at sites substantially different from those targeted by PKA. Furthermore, we show that the primary phosphorylation sites lie between amino acid residues 212-231 (using numbering system for the longest T, which is the isoform with four "repeats" and a 58 amino acid "insert" at the carboxyl- and amino-termini, respectively, of the protein molecule).

Alzheimer Disease↗
PubMed1995

Growth modulation of human prostatic cancer cells by interleukin-1 and interleukin-1 receptor antagonist.

The effects of interleukin-1 (IL-1 alpha or IL 1 beta) on androgen-dependent LNCaP and androgen-independent JCA-1 human prostatic cancer cell proliferation were investigated. IL-1 alpha or IL-1 beta induced a dose dependent growth reduction by 50-80% as determined by cell cycle phase distribution, cell number and clonal growth in short and long term cultures. IL-1 negated the androgen growth effect on equal molar basis but the androgen receptors were not blocked by IL-1. The presence of intracellular IL-1 receptors was detected by flow cytometry and the IL-1 mediated growth reduction could be blocked with a 500 fold excess of the IL-1 receptor antagonist (hIL-1ra), revealing a growth control involving IL-1, HIL-1ra, androgen and their receptors.

Cell Division↗
PubMed1995

Growth regulation and cellular changes during differentiation of human prostatic cancer LNCaP cells as induced by T lymphocyte-conditioned medium.

Human prostatic epithelial cells from an androgen-dependent LNCaP cell line were examined in response to conditioned medium (CM) derived from phytohemagglutinin (PHA)-stimulated lymphocytes. Addition of CM caused a greater than 70% reduction of cell proliferation by cell counting and cell cycle. These cells showed G1 phase arrest and the clonogenicity was reduced. The growth-modulating effect was dose-dependent and not due to cell lysis or apoptosis. The binding of androgen to androgen receptor on these cells showed approximately 50% reduction, underlining a proliferation reduction mechanism. The prostate-specific antigen (PSA) was downregulated to approximately 75% during the process. Cell morphology showed dendritic processes extending from cytoplasm and other neuroendocrine cell characteristics. The expression of several cytoskeleton and intracellular proteins increased as determined by immunostaining on slides and by ELISA procedures. These included vimentin, correlating to cell shape changes, cytokeratins 8 and 18, associated with differentiated cell types of prostate epithelia, and neuron-specific enolase and serotonin, associated with neuroendocrine cells. From these cellular changes, we can infer that the cell growth was modulated along with induction of terminal differentiation. Activated T cells were demonstrated to be important in providing the modulating activity. This growth modulator was semipurified and had an estimated molecular weight 13,000 to 24,000 Da. The activity was determined to be distinct from TGF, TNF, and some commonly known lymphokines. The interaction between lymphoid and prostatic cells in growth and development is described.

Biomarkers↗
PubMed1995

Growth attenuation in a human prostate cell line mediated by a phorbol ester.

Human prostatic cancer cells JCA-1 were induced with a phorbol ester 12-o-tetradecanoylphorbol-13-acetate (TPA), and cell growth differentiation were analyzed. Within hours of exposure to TPA, cell proliferation decreased and reached approximately 80% reduction after 3 days, as determined by [3H]thymidine incorporation and cell counting. Cell cycle analysis revealed a blocking of cells entering into the replicating S and G2M phases from the G1 phase. The TPA induced cells had a reduced growth rate but remained viable. The growth-modulating activity of TPA was similarly observed with LNCaP cells. Agarose gel electrophoresis of the chromosomal DNA from induced cells exhibited a non-fragmented pattern excluding the possibility of cell apoptosis. In parallel to the growth reduction, the TPA induced cells became larger in size showing dendrite like cytoplasmic extensions. Furthermore, JCA-1 cells treated with TPA acquired the expression of cytokeratin 18 and increased the expression of actin and vimentin by 300%. These results indicate an induced growth reduction accompanied by cellular differentiation of the prostatic cancer cells.

Cell Cycle↗