Involvement of Oxidative Stress in Cisplatin-Induced Apoptosis in HeLa Cells / 대한산부인과학회잡지

OBJECTIVE: To determine whether oxidants are formed as part of the cisplatin-induced apoptotic process, intracellular markers of oxidative stress were examined. METHODS: Apoptotic death of HeLa cells by cisplatin was confirmed by flow cytometry. RESULTS: The pre-treatment with glutathione (GSH) significantly attenuated cisplatin-induced apoptosis through the reduction of reactive oxygen species (ROS) accumulation and diminished caspases-3 and 9 protease activity. Furthermore, z-VAD-fmk, an inhibitor of pan-caspase, effectively inhibited the activation of caspases and prevented apoptosis by cisplatin, although cisplatin-induced ROS generation was not attenuated. CONCLUSION: These data indicate that ROS may play a role as an upstream mediator of caspases. Taken together, our results suggest that oxidative stress mediates cisplatin-induced apoptosis in HeLa cells.

The Mechanism of Intracellular Signal Pathway that Baicalin Hydrate Elevate Chemotherapeutic Response of Cervical Carcinoma / 대한산부인과학회잡지

Baicalin is flavonoid and major component of PC-SPES. Flavonoids including baicalin have been reported to not only function as anti-oxidant but also cause cytotoxic effect. Baicalin hydrate has been reported to induce cell death, however the mechanism by which baicalin hydrate induces the apoptosis of cancer cells is still unclear. To evaluate the mechanistic insights of apoptosis by baicalin hydrate, we tested the activities of apoptosis signaling pathway in HeLa cells. The viability of HeLa and HeLa s3 cells was markedly decreased by baicalin hydrate in a dose- and time- dependent method. Baicalin hydrate induced the apoptotic death of HeLa cells, which was characterized by the chromatin condensation of the nuclei and phosphorylation of histone H2AX. Baicalin hydrate increased the sub-G1 DNA content of HeLa cell lines. Baicalin hydrate digested Bid protein, increased Bak protein level and also, induced mitochondrial dysfunction disrupted as shown as the mitochondrial membrane potential. It activated caspase-3, thereby resulted in cleavage of poly (ADP) ribose polymerase (PARP).

The Study of the Cytotoxic Mechanism of Cisplatin in HeLa Cells / 대한산부인과학회잡지

Cis-diamminedichloroplatinum II (cisplatin) has been reported to induce cell death. However, the mechanism by which cisplatin is induced the apoptosis of cancer cells is still unclear. To evaluate the mechanistic insights of apoptosis by cisplatin, we tested the activities of apoptotic signaling pathway in HeLa cells. Apoptotic death of HeLa cells by cisplatin was confirmed by ladder-pattern fragmentation of genomic DNA. Cisplatin induced the activation of caspase-3 and 9 proteases in a time dependent manner. The caspase-3 protease activation and the cleavage of poly (ADP-ribose) polymerase (PARP) and procaspase-3 was demonstrated. We also showed that the expression of Bcl-2 and Bcl-xL was markedly decreased by the addition of cisplatin in HeLa cells. Moreover, expression of Fas and FasL proteins was increased by cisplatin. These data suggest that cisplatin triggers the activation of apoptotic signaling pathway in human cervical cancer, HeLa cells, via affects the expression of Fas, FasL and Bcl-2 families as well as triggers the activation of caspase-3 and -9 proteases.