厚朴的兩個主要成分Honokiol及Magnolol已知可對抗癌症。本研究是以人類鱗狀肺癌CH27細胞來探討Honokiol及Magnolol如何誘發細胞凋亡。研究發現Honokiol及Magnolol呈現劑量及時間依存性使細胞進行死亡。由細胞形態的改變、DAPI及TUNEL螢光染色、DNA斷片形成結果得知此兩成分明顯誘導細胞凋亡。處理Honokiol及Magnolol會使細胞內Bad表現量增加，Bcl-XL表現量減少。此外，當細胞大量表現Bcl-2蛋白時，可保護細胞對抗Honokiol及Magnolol所誘發之細胞死亡。Honokiol及Magnolol之處理，亦會造成粒線體內之cytochrome c釋放至細胞質中，進而引起caspase-9的活化，在活化下游caspase-3，造成PARP被caspase-3分解，引起細胞凋亡。若處理廣效性caspases抑制劑z-VAD-fmk，可明顯抑制Honokiol及Magnolol所引起CH27細胞的死亡，但不會抑制粒線體釋放cytochrome c。此外，Honokiol及Magnolol會引起適度且持續性的JNK活化，並抑制ERK的活性。以上結果顯示，Honokiol及Magnolol誘發細胞凋亡之路徑，是經由一連串細胞內的分子，如MAPK家族、Bcl-2家族、粒線體cytochrome c釋放及caspases活化等等。; Honokiol and Magnolol are phenolic compounds isolated from the root and stem bark of Magnolia officinalis, which exhibit antitumour effects. In the present study, the molecular mechanism of Honokiol and Magnolol-mediated apoptotic process was examined in human lung squamous carcinoma CH27 cells. We found that treatment with Honokiol and Magnolol resulted in dose- and time-dependent decrease in cell viability. Moreover, both of them significantly induced apoptosis evidenced by morphological changes, DAPI staining, TUNEL assay and DNA fragmentation. Honokiol and Magnolol increased the expression of Bad protein, whereas decreased the expression of Bcl-XL. Moreover, overexpression of Bcl-2 protected CH27 cells against Honokiol and Magnolol-triggered apoptosis. Honokiol and Magnolol caused the release of mitochondrial cytochrome c to cytosol and sequential activation of caspases. Proteolytic activation of caspase-3 and cleavage of PARP were observed in Honokiol and Magnolol-induced apoptosis. Pretreatment with z-VAD-fmk markedly inhibited Honokiol and Magnolol-induced cell death, but did not prevent cytosolic cytochrome c accumulation. Furthermore, Honokiol and Magnolol induced a modest and persistent JNK activation and ERK inactivation. These results indicated that regulation of the MAPK family and Bcl-2 family molecules, release of mitochrondrial cytochrome c, and activation of caspase cascade may be the molecular mechanisms of Honokiol and Magnolol-induced apoptosis in the CH27 cells.
