OBJECTIVE: To investigate the cytotoxic effect of 5-fluorouracil (5Fu) on HPV16-associated laryngeal cancer cells. DESIGN AND METHODS: Cytotoxicity assay and TUNEL assay were used to assess the effect of 5Fu on laryngeal cancer cells transfected with HPV16 E6 or E7. RESULTS: 5Fu induced apoptosis in the cells either with or without HPV16 in a dose- and time-dependent manner. 5Fu caused the accumulation of active pRb and p21(WAF1/CIP1), together with an increase in Bak and Bax expression and a decrease in Bcl-2 levels in all the transfected cells. G(1)/S phase cell cycle arrest was associated with the antiproliferation activity of 5Fu. 5Fu also presented some effects on the E6 and E7 oncoproteins. CONCLUSIONS: HPV16 E6 and E7 oncoproteins do not prevent 5Fu-medicated apoptosis and G(1)/S cell arrest in laryngeal cancers. The sensitivity of 5Fu treatment is associated with the decrease of Bcl-2 and/or the increase in Bak and p21(WAFI/CIP1).
OBJECTIVE: To investigate the cytotoxic effect of 5-fluorouracil (5Fu) on HPV16-associated laryngeal cancer cells. DESIGN AND METHODS: Cytotoxicity assay and TUNEL assay were used to assess the effect of 5Fu on laryngeal cancer cells transfected with HPV16 E6 or E7. RESULTS:5Fu induced apoptosis in the cells either with or without HPV16 in a dose- and time-dependent manner. 5Fu caused the accumulation of active pRb and p21(WAF1/CIP1), together with an increase in Bak and Bax expression and a decrease in Bcl-2 levels in all the transfected cells. G(1)/S phase cell cycle arrest was associated with the antiproliferation activity of 5Fu. 5Fu also presented some effects on the E6 and E7 oncoproteins. CONCLUSIONS:HPV16 E6 and E7 oncoproteins do not prevent 5Fu-medicated apoptosis and G(1)/S cell arrest in laryngeal cancers. The sensitivity of 5Fu treatment is associated with the decrease of Bcl-2 and/or the increase in Bak and p21(WAFI/CIP1).