Résumé
OBJECTIVE:To study the reversal mechanism of oxymatrine on multidrug resistance in the NPC HNE-1(200) cell line. METHODS: The multidrug resistant HNE-1(200) subline was derived from an HNE-1 cell line after exposure to fractionated X-irradiation. The expression of P-gp was tested by immunocytochemical method and western blot and that of mdr1 mRNA was measured by RT-PCR. RESULTS: After 24-hour treatment with oxymatrine, both the immunocytochemical method and western blot showed a decrease in the expression of P-gp. However, RT-PCR measurement showed that the expression of mdr1 mRNA of HNE-1 and HNE-1(200) was nonsignficant. CONCLUSION: Oxymatrine can reverse the multidrug resistance of NPC HNE-1(200) cell line to some degree by down-regulating the expression of P-gp. However, this medicine did no effect on the expression of mdr1 mRNA, suggesting the up-regulation of the expression of P-gp is under the control of multiple mechanism.
Résumé
OBJECTIVE: To study the joint action of tea polyphenols and common anti-tumor drugs(vincristine,pingyangmycin,5-Fu,cisplatin) in inhibiting cell proliferation of the multiresistant HNE-1(200) cell line in patients with nasopharyngeal carcinoma after radiographic exposure.METHODS: The low toxic dosage of tea polyphenols and 4 kinds of anti-tumor drugs were optimized by MTT method.Then the inhibition ratio of multiresistant HNE-1(200) cell line treated by tea polyphenols and anti-tumor drugs waere detected.RESULTS: The low toxic dosage of tea polyphenols was 0.50 mg?mL-1.When the anti-tumor drugs were used in combination with tea polyphenols(0.50 mg?mL-1) as compared without,the inhibition ratio on HNE-1(200) cell line was increased by 100%～300%.CONCLUSIONS: Addition of tea polyphenols to anti-tumor drugs showed remarkable inhibitory effect on cell proliferation of HNE-1(200) cell line in patients with nasopharyngeal carcinoma,suggesting the reverse effect of tea polyphenols on resistant HNE-1(200) cell line.