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Articles by H. C Chuang
Total Records ( 2 ) for H. C Chuang
  J. N Al Swiahb , C. C Huang , F. M Fang , H. C Chuang , H. Y Huang , S. D Luo , C. H Chen , C. M Chen and C. Y. Chien
 

Objective  To evaluate the prevalence of human papillomavirus (HPV) and the prognostic significance of epidermal growth factor receptor (EGFR), p53, and p16 among patients with oropharyngeal carcinoma.

Design  Retrospective study.

Setting  Academic Institute of Otolaryngology, Kaohsiung, Taiwan.

Patients  Two hundred seventy-four patients who were diagnosed as having oropharyngeal carcinoma underwent testing for the presence of the HPV genome in the nuclei of their tumor cells from January 1, 1992, through March 31, 2008.

Interventions  The HPV genome was detected by performing polymerase chain reaction–based assays and in situ hybridization on tumor tissue from paraffin blocks. Immunohistochemistry staining for p16, p53, and EGFR was also performed.

Main Outcome Measures  We used the Fisher exact test to evaluate the correlation between the clinicopathological variables and the presence of HPV in tumor cells. Survival analysis was based on the Kaplan-Meier method.

Results  We detected HPV in 45 of the 274 patients (16.4%); of these, HPV-16 and -18 were identified in 42 (93.3%) of the HPV-positive tumors. The HPV-positive oropharyngeal cancers were more likely to occur in females, nonsmoking individuals, and those who did not chew betel quid. The HPV-positive tumors significantly expressed p16 and were inversely associated with EGFR and p53 expression (all, P < .001). In addition, patients with tumor tissue that was positive for HPV (P = .008) and had negative expression of EGFR (P = .01), low expression of p53 (P = .01), and high expression of p16 (P = .04) had a better prognosis.

Conclusion  Our results suggest that HPV, EGFR, p53, and p16 are useful biomarkers in predicting the clinical outcomes of oropharyngeal cancer.

  P. H Huang , D Wang , H. C Chuang , S Wei , S. K Kulp and C. S. Chen
 

As part of our effort to understand the mechanism underlying -tocopheryl succinate [vitamin E succinate (VES)]-mediated antitumor effects, we investigated the signaling pathway by which VES suppresses androgen receptor (AR) expression in prostate cancer cells. VES and, to a greater extent, its truncated derivative TS-1 mediated transcriptional repression of AR in prostate cancer cells but not in normal prostate epithelial cells; a finding that underscores the differential susceptibility of normal versus malignant cells to the antiproliferative effect of these agents. This AR repression was attributable to the ability of VES and TS-1 to facilitate the proteasomal degradation of the transcription factor Sp1. This mechanistic link was corroborated by the finding that proteasome inhibitors or ectopic expression of Sp1 protected cells against drug-induced AR ablation. Furthermore, evidence suggests that the destabilization of Sp1 by VES and TS-1 resulted from the inactivation of Jun N-terminal kinases (JNKs) as a consequence of increased phosphatase activity of protein phosphatase 2A (PP2A). Stable transfection of LNCaP cells with the dominant-negative JNK1 plasmid mimicked drug-induced Sp1 repression, whereas constitutive activation of JNK kinase activity or inhibition of PP2A activity by okadaic acid protected Sp1 from VES- and TS-1-induced degradation. From a mechanistic perspective, the ability of VES and TS-1 to activate PP2A activity underscores their broad spectrum of effects on multiple signaling mechanisms, including those mediated by Akt, mitogen-activated protein kinases, nuclear factor kappaB, Sp1 and AR. This pleiotropic effect in conjunction with low toxicity suggests the translational potential for developing TS-1 into potent PP2A-activating agents for cancer therapy.

 
 
 
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