Wai-Pui Tse

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (4)10.56 Total impact

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    ABSTRACT: Traditional Chinese medicine has long been used to treat a variety of ailments including skin diseases. Our previous study has revealed the ethanolic extract of realgar, a common ingredient used in psoriasis treatment in Chinese medicine, to possess potent anti-proliferative action on cultured HaCaT cells of human keratinocyte origin. In the present study, the mechanisms of action of the observed growth inhibitory action of realgar were investigated. Several bioassay methods were employed to elucidate whether cellular apoptosis is involved in the realgar-induced growth inhibition of the skin cells. Morphologically, nuclear condensation and DNA fragmentation were observed when HaCaT cells were exposed to the realgar extract. DNA fragmentation induced by the treatment of realgar was also evident as detected by gel electrophoresis and the TUNEL method. Cell cycle analysis by propidium iodide (PI) staining demonstrated the appearance of sub-G1 peak and cell cycle arrest at the G1 phase upon realgar treatment. Quantitative analysis by annexin V-PI staining revealed that the realgar-induced apoptotic event was dose-dependent. Furthermore, realgar was able to activate caspase-3 expression when examined by Western blot analysis. Our experimental data unambiguously confirm that induction of cellular apoptosis is mainly responsible for the observed growth inhibition brought about by realgar on the HaCaT keratinocytes, and this finding helps place the traditional use of this mineral for psoriasis treatment on a scientific footing.
    International Journal of Molecular Medicine 09/2009; 24(2):189-96. · 1.96 Impact Factor
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    ABSTRACT: Arsenic compounds have been traditionally used to treat a variety of ailments, including skin diseases. Our previous study identified the extract of realgar to possess potent antiproliferative action on HaCaT cells. The present study aimed at evaluating whether several inorganic arsenics found in realgar also possess similar antiproliferative properties. The results showed that arsenic trioxide, arsenic pentoxide, and arsenic iodide had significant antiproliferative action on HaCaT cells, with IC(50) values at 2.4, 16, and 6.8 microM, respectively. However, these compounds only modestly inhibited the growth of Hs-68 cells, a normal human skin fibroblast cell line, with IC(50) values at 43.4, 223, and 89 microM, respectively, conferring a favorable toxicity profile. In mechanistic studies, all three compounds caused DNA fragmentation as demonstrated by gel electrophoresis and the terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling method. Morphologically, nuclear condensation and DNA fragmentation were observed when the cells were exposed to arsenic compounds. Cell cycle analysis with propidium iodide (PI) staining demonstrated the appearance of sub-G(1) peak and cell arrest at the G(1) phase in the presence of these compounds. Quantitative analysis by annexin V-PI staining revealed that the arsenic-induced apoptotic event was dose-dependent. Moreover, the arsenic compounds were able to activate caspase-3 expression when examined by Western blot analysis. Our experimental data unambiguously demonstrated that induction of cellular apoptosis was mainly responsible for the observed antiproliferation brought about by the arsenic compounds on HaCaT keratinocytes, suggesting that these arsenic compounds are putative agents from which psoriasis-treating topical formulae could be developed.
    Journal of Pharmacology and Experimental Therapeutics 09/2008; 326(2):388-94. · 3.89 Impact Factor
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    ABSTRACT: Psoriasis is a chronic inflammatory skin disease characterized histologically by hyperproliferation and aberrant differentiation of epidermal keratinocytes. While screening 60 psoriasis-treating Chinese herbs for their anti-proliferative properties using a cultured human HaCaT keratinocyte model, we found Radix Rubiae to be highly effective. Evidence is now provided that induction of apoptosis is the underlying mechanism for the observed anti-proliferative action of Radix Rubiae. Analysis of cell cycle with PI staining showed that Radix Rubiae induced the appearance of a sub-G1 peak and cell arrest at the G1 phase. Radix Rubiae was also capable of inducing morphological changes as evidenced by nuclear condensation. DNA fragmentation was clearly demonstrated by gel electrophoresis and by the TUNEL method. Quantitative analyses by Annexin V-PI staining revealed that Radix Rubiae-induced apoptosis was dose- and time-dependent. Furthermore, Radix Rubiae was able to activate caspase-3 expression when examined by Western blot analysis. The cellular, morphological and molecular data unequivocally demonstrated that induction of cellular apoptosis was mainly responsible for the previously observed anti-proliferation induced Radix Rubiae on HaCaT keratinocytes. Our experimental results suggest that Radix Rubiae is a promising source from which a herb-based topical agent could be developed for psoriasis treatment.
    International Journal of Molecular Medicine 12/2007; 20(5):663-72. · 1.96 Impact Factor
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    ABSTRACT: Psoriasis is a chronic inflammatory skin disorder, which affects approximately 2-3% of the population worldwide. The current conventional therapy cannot offer satisfactory clinical results for most of the patients, largely due to the fact that many anti-psoriatic drugs have serious side effects and psoriasis is prone to developing drug resistance after long term exposure. Traditionally, Chinese herbal medicine has been extensively used to treat psoriasis and produced promising clinical results; however, its underlying mechanisms of action have not been systematically investigated. The aim of this study was to investigate those Chinese medicinal materials, which are commonly prescribed in Chinese medicine practice for psoriasis, for their anti-proliferative effects on HaCaT cells in vitro. Sixty Chinese medicinal materials were selected and extracted with 80% aqueous ethanol. The dry extracts were evaluated for their anti-proliferative activities by microplate SRB and MTT assays. Three Chinese medicinal materials i.e. the root of Rubia cordifolia L. (Rubiaceae), Realgar and the rhizome of Coptis chinensis Franch. (Ranunculaceae) were found to have significant anti-proliferative effects, with IC(50) being 1.4, 6.6 and 23.4 microg/ml, respectively as measured by MTT assay. While Realgar was also able to modestly inhibit the growth of Hs-68 cells in vitro, Rubia cordifolia and Coptis chinensis did not exert cytotoxicity to this human fibroblast cell line.
    Journal of Ethnopharmacology 12/2006; 108(1):133-41. · 2.76 Impact Factor