Cisplatin induces apoptosis in oral squamous carcinoma cells by the mitochondria-mediated but not the NF-κB-suppressed pathway

• Published in: Oral oncology 2003-04, Vol.39 (3), p.282-289
• Main Authors: Azuma, M, Tamatani, T, Ashida, Y, Takashima, R, Harada, K, Sato, M
• Format: Article
• Language: English
• Subjects: Antiapoptotic proteins; Antineoplastic agents; Apaf-1; Biological and medical sciences; Caspases; Chemotherapy; Cytochrome c; Medical sciences; NF-κB; Oral cancer cells; Otorhinolaryngology. Stomatology; Pharmacology. Drug treatments; Tumors; Upper respiratory tract, upper alimentary tract, paranasal sinuses, salivary glands: diseases, semeiology
• ISSN: 1368-8375; 1879-0593
• DOI: 10.1016/S1368-8375(02)00116-1

Cisplatin (CDDP) is a potent DNA-damaging anticancer agent, and its cytotoxic action is exerted by the induction of apoptosis. However, activation of the transcription factor NF-κB results in protection against apoptosis. We examined the molecular mechanisms involved in the induction of apoptosis by CDDP as regards both suppression of NF-κB and activation of caspases. Human oral squamous carcinoma cells (B88) were employed in this study. We found that CDDP treatment affected neither NF-κB activity nor the expression levels of antiapoptotic proteins, including TRAF-1, TRAF-2, and cFLIP, in B88 cells. However, two apoptosome molecules, cytochrome c and Apaf-1, were significantly augmented in the cytoplasm by CDDP treatment. Further, the activation of caspase-9 and caspase-3, downstream molecules leading to mitochondria-mediated apoptosis, were detected after treatment with CDDP. Finally, apoptosis was also clearly observed, as evidenced by cleavage of PARP through the activation of caspase-3. These findings suggest that CDDP exerts its apoptotic action by the mitochondria-mediated activation of caspases but not by the activation of caspases due to the inhibition of NF-κB activity that follows the suppression of antiapoptotic proteins.