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Eugene Chang

Publications and source records attributed to Eugene Chang.

11 recordsLinked to original sources
PubMed2007

Alpha-vitamin E derivative, RRR-alpha-tocopheryloxybutyric acid inhibits the proliferation of prostate cancer cells.

AIM: To investigate the activity of RRR-alpha-tocopheryloxybutyric acid (TOB), an ether analog of RRR-alpha-tocopheryl succinate (VES), in prostate cancer cells. METHODS: VES and TOB were used to treat prostate cancer LNCaP, PC3, and 22Rv1 cells and primary-cultured prostate fibroblasts. The proliferation rates were determined by MTT assay, the cell viabilities were determined by trypan blue exclusion assay, and the cell deaths were evaluated by using Cell Death Detection ELISA kit. The protein expression levels were determined by Western blot analysis. RESULTS: The MTT growth assay demonstrated that TOB could effectively suppress the proliferation of prostate cancer cells, but not normal prostate fibroblasts. Mechanism dissections revealed that TOB reduced cell viability and induced apoptosis in prostate cancer cells similar to VES. In addition, both TOB and VES suppressed prostate-specific antigen (PSA) at the transcriptional level leading to reduced PSA protein expression. Furthermore, vitamin D receptor (VDR) expression increased after the addition of TOB. CONCLUSION: Our data suggests that the VES derivative, TOB, is effective in inhibiting prostate cancer cell proliferation, suggesting that TOB could be used for both chemopreventive and chemotherapeutic purposes in the future.

Antineoplastic Agents↗
PubMed2005

Targeting vaccinia to solid tumors with local hyperthermia.

We have previously demonstrated that mutant vaccinia viruses target tumors in vivo after systemic delivery, and they have potential as vectors for tumor-directed gene therapy. We hypothesized that hyperthermia may augment vaccinia delivery to tumors after systemic injection, as hyperthermia increases the permeability of the endothelial vasculature to nanoparticles. In our in vitro experiments, we have shown that hyperthermia does not alter tumor cells' susceptibility to the intrinsic cytopathogenicity of the vaccinia virus compared with normothermic controls. Hyperthermia also does not change the viral infectivity or the level of viral marker gene expression when compared with normothermia. In an in vitro model of endothelial cell monolayer permeability, we have demonstrated that hyperthermia increases the permeability of the monolayer to vaccinia virus and that this phenomenon is completely reversible. In vivo we have demonstrated that the tumors that were treated with systemic vaccinia under conditions of hyperthermia (41.5 degrees C for 30 min) had significantly higher levels of vaccinia marker gene activity (>100-fold) than those treated under normothermic conditions (p < 0.05) and that this effect was specific to tumor. We also demonstrated that mice with 1 cm subcutaneous tumors treated with a systemically delivered, conditionally replicating vaccinia under conditions of hyperthermia had complete tumor regression in 50% and significantly improved antitumor response, compared with normothermic viral-treated controls (mean tumor volume of 110 mm(3) vs 3169 mm(3), 13 days after treatment) and compared with hyperthermic, nonvirally treated control animals (p < 0.0001). Regional hyperthermia improves vaccinia targeting to tumors, and thereby enhances the antitumor response.

Animals↗
PubMed2004

Bilateral reduction mammoplasty in combination with lumpectomy for treatment of breast cancer in patients with macromastia.

BACKGROUND: Bilateral reduction mammoplasty has been described as a surgical option for treatment of breast cancer in women with large, pendulous breasts. Using this technique can provide unique surgical oncologic challenges. METHODS: Retrospective chart review. RESULTS: Thirty-seven patients were identified. The average weight of tissue removed was 653 g. Tumor size ranged from 0.6 to 5.2 cm. One patient had microscopically positive surgical margins on final pathology. The tumor bed was not marked, and completion mastectomy was required. Two patients had unexpected malignancy in the contralateral breast. One patient required completion mastectomy for positive nonoriented margins. In another patient, tissue from the contralateral side was oriented, and mastectomy was avoided. CONCLUSIONS: Bilateral reduction mammoplasty with lumpectomy is an ideal option in women with macromastia. We recommend marking the tumor bed on the flaps and pedicle as well as orienting tissue removed from the contralateral side as maneuvers that will decrease need for completion mastectomy.

Adenocarcinoma, Mucinous↗
PubMed2004

Outcomes for children with submucous cleft palate and velopharyngeal insufficiency.

OBJECTIVE: To review the outcomes of children with submucous cleft palate who also have velopharyngeal insufficiency (VPI). METHODS: A retrospective chart review was carried out at a tertiary care academic centre of all patients who had VPI with a submucous cleft palate. The University of Iowa Cleft Palate registry parameters encompassing nasality (hyper- and hyponasality) were compared pre- and postoperatively. RESULTS: Preliminary results demonstrate a significant, stable improvement in children who underwent palatal surgery for VPI. CONCLUSION: Positive outcomes in the treatment of VPI in the submucous cleft palate population were demonstrated with a combined approach of speech therapy and palatal surgery.

Child, Preschool↗
PubMed2003

Antitumor agents 222. Synthesis and anti-androgen activity of new diarylheptanoids.

Fifteen new diarylheptanoids were synthesized and evaluated for antagonistic activity against androgen receptor (AR)-mediated reporter gene transcription using DU145, PC-3, and LNCaP prostate cancer cell lines. Most compounds showed activity in a 5alpha-dihydrotestosterone (DHT)-induced reporter gene expression assay in DU145 cells transfected with wild-type AR. Ten compounds (5, 8, 10, 14-15, and 18-22) were equipotent with hydroxyflutamide (HF), the anti-androgen currently available for the treatment of prostate cancer. However, except for compounds 5 and 10, none of the tested compounds was significantly effective in attenuating DHT-induced reporter gene expression in LNCaP cells, which contain endogenous mutant AR.

Androgen Antagonists↗
PubMed2003

Differential and bi-directional regulation between TR2/TR4 orphan nuclear receptors and a specific ligand mediated-peroxisome proliferator-activated receptor alpha in human HaCaT keratinocytes.

BACKGROUND: We have reported that human TR2 orphan nuclear receptor (TR2) can modulate the transcriptional activity of the reporter gene containing an AGGTCA direct repeat-hormone response element. OBJECTIVE: The aim of this study is to investigate the potential role and regulation of TR2 in human HaCaT keratinocytes. METHODS: We performed mainly chloramphenicol acetyltransferase reporter gene assays (CAT assays), and Western blot analysis. RESULTS: From CAT assays, TR2 can suppress retinoic acid (RA)-induced transactivation by 44.7% in HaCaT keratinocytes. This suppression is similar to our previous report showing TR4 orphan nuclear receptor (TR4) can suppress RA-induced transactivation. However, TR4 but not TR2 can significantly repress Wy-14643-mediated peroxisome proliferator-activated receptor alpha (PPAR alpha) transactivation by 95%. Western blot analysis suggested that Wy-14643 can differentially regulate the expression of TR2 and TR4 (by increasing the expression of TR4 protein and decreasing that of TR2) in HaCaT keratinocytes. CONCLUSION: Our data not only provides the first evidence to demonstrate that close members of orphan nuclear receptors group, such as TR2 and TR4, can have distinct functions, but also suggests the existence of differential and bi-directional regulation between PPAR alpha and TR2/TR4, that may play some important roles in the PPAR alpha signaling pathway in human keratinocytes.

Binding, Competitive↗
PubMed2003

Pseudomonas aeruginosa expresses a lethal virulence determinant, the PA-I lectin/adhesin, in the intestinal tract of a stressed host: the role of epithelia cell contact and molecules of the Quorum Sensing Signaling System.

OBJECTIVE: We have previously demonstrated that P. aeruginosa can have profound effects on the intestinal epithelial barrier via one of its virulence factors, the PA-I lectin/adhesin. The aims of the present study were to further characterize the interaction of P. aeruginosa and the intestinal epithelium using both in vitro and in vivo approaches. METHODS: In vitro assays examining the effect of bacterial growth phase, epithelial cell contact, and butanoyl homoserine lactone (C4-HSL), a quorum sensing signaling molecule know to affect various extracellular virulence factors in P. aeruginosa, on PA-I expression in P. aeruginosa were performed. In vivo studies were carried out by modeling catabolic stress in mice using a 30% surgical hepatectomy and direct introduction of P. aeruginosa and various virulence components into the cecum. The effect of this model on PA-I expression in P. aeruginosa was determined. RESULTS: Results demonstrated that PA-I expression in P. aeruginosa is affected by its phase of growth, its contact to the intestinal epithelium, and its exposure to the quorum sensing molecule, C4-HSL. Furthermore, data from the present study suggest that the PA-I lectin/adhesin of P. aeruginosa may be increased in vivo by local factors within the cecum of mice in response to surgical stress. CONCLUSIONS: These data indicate that multiple factors present in the intestinal microenvironment of a stressed host may induce certain opportunistic pathogens to express key virulence factors leading to a state of lethal gut-derived sepsis.

Adhesins, Bacterial↗
PubMed2002

Antitumor agents. 217. Curcumin analogues as novel androgen receptor antagonists with potential as anti-prostate cancer agents.

A number of curcumin analogues were prepared and evaluated as potential androgen receptor antagonists against two human prostate cancer cell lines, PC-3 and DU-145, in the presence of androgen receptor (AR) and androgen receptor coactivator, ARA70. Compounds 4 [5-hydroxy-1,7-bis(3,4-dimethoxyphenyl)-1,4,6-heptatrien-3-one], 20 [5-hydroxy-1,7-bis[3-methoxy-4-(methoxycarbonylmethoxy)phenyl]-1,4,6-heptatrien-3-one], 22 [7-(4-hydroxy-3-methoxyphenyl)-4-[3-(4-hydroxy-3-methoxyphenyl)acryloyl]-5-oxohepta-4,6-dienoic acid ethyl ester], 23 [7-(4-hydroxy-3-methoxyphenyl)-4-[3-(4-hydroxy-3-methoxyphenyl)acryloyl]5-oxohepta-4,6-dienoic acid], and 39 [bis(3,4-dimethoxyphenyl)-1,3-propanedione] showed potent antiandrogenic activities and were superior to hydroxyflutamide, which is the currently available antiandrogen for the treatment of prostate cancer. Structure-activity relationship (SAR) studies indicated that the bis(3,4-dimethoxyphenyl) moieties, the conjugated beta-diketone moiety, and the intramolecular symmetry of the molecules seem to be important factors related to antiandrogenic activity. The data further suggest that the coplanarity of the beta-diketone moiety and the presence of a strong hydrogen bond donor group were also crucial for the antiandrogenic activity, which is consistent with previous SAR results for hydroxyflutamide analogues. When the pharmacophoric elements of dihydrotestosterone (DHT) and compound 4 are superposed, the resulting construct implies that the curcumin analogues may function as a 17alpha-substituted DHT. Compounds 4, 20, 22, 23, and 39 have been identified as a new class of antiandrogen agents, and these compounds or their new synthetic analogues could be developed into clinical trial candidates to control androgen receptor-mediated prostate cancer growth.

Androgen Antagonists↗
PubMed2002

Vitamin E succinate inhibits the function of androgen receptor and the expression of prostate-specific antigen in prostate cancer cells.

Although epidemiological evidence indicates that a daily supplement of vitamin E may reduce the risk of prostate cancer, the detailed mechanism underlying this effect remains unclear. Here we demonstrate that alpha-tocopheryl succinate (VES) can suppress the expression of prostate-specific antigen (PSA), a marker for the progression of prostate cancer. VES can also suppress androgen receptor (AR) expression by means of transcriptional and posttranscriptional modulation, but not ligand binding, nuclear translocation, or AR dimerization. This VES-mediated inhibition of AR is selective because VES does not repress the expression of other nuclear receptors. Cell growth studies further show that VES inhibits the growth of prostate cancer LNCaP cells. In contrast, hydroxyflutamide (HF), an antiandrogen currently used to treat prostate cancer patients, only slightly inhibits LNCaP cell growth. Interestingly, simultaneous addition of HF and VES results in a more significant inhibition of LNCaP cell growth. Moreover, selenomethionine (SM), a prostate cancer treatment adjuvant, shows an inhibitory effect on LNCaP cell growth, yet has no effect on the AR/PSA pathway. Together, our data indicate that VES may suppress androgen/AR-mediated cell growth and PSA expression by inhibiting AR expression at both the transcription and translation levels. This previously undescribed mechanism may explain how VES inhibits the growth of prostate cancer cells and help us to establish new therapeutic concepts for the prevention and treatment of prostate cancer.

Androgen Receptor Antagonists↗
PubMed2002

Immunologic basis for diarrhea.

Diarrhea is a common sequela of deregulated immune pathways underlying the wide range of intestinal acute and chronic diseases. The ongoing investigation of novel immune components and susceptibility factors allows better understanding of these pathologic mechanisms and continues to advance therapeutic options.

Journal Article↗