Agent for overcoming resistance to anti-cancer agent

A method for overcoming drug resistance using a compound having the following formula (II) or a salt thereof as an active ingredient for overcoming drug resistance:

• wherein R1 is C6-10 aryl or heteroaryl in which the aryl and heteroaryl can have a substituent selected from the group consisting of C1-8 alkyl, C1-8 alkyl substituted with halogen, C1-8 alkoxy, C1-8 alkoxy substituted with C1-8 alkoxy, C2-8 alkoxycarbonyl, formyl, carboxyl, halogen, hydroxyl, nitro, cyano, amino, C6-10 aryl, and C6-10 aryloxy;
• R2 is cyano, nitro, formyl, carboxyl, carbamoyl, or C2-8 alkoxycarbonyl;
• R3 is hydroxyl, amino, carboxyl, mercapto, OR4, or NHR5, and each of R4 and R5 is C1-8 alkyl or C1-8 alkyl substituted with a group or atom selected from the group consisting of halogen, hydroxyl, nitro, cyano, amino, C6-10 aryl, and C6-10 aryloxy;
• X is oxygen, —N(R6)—, or —S(O)n—, and R6 is a hydrogen, alkyl, or the group mentioned above for R1, and n is an integer of 0 to 2;
• and
• Y is oxygen or sulfur.

A method for overcoming anti-cancer chemotherapeutic drug resistance comprising contacting a chemotherapeutic drug-resistant cell with an agent containing a compound having the following formula (I) or a salt thereof as an active ingredient for overcoming anti-cancer chemotherapeutic drug resistance:

• wherein R1 is C2-8 alkenyl, C6-10 aryl, or heteroaryl in which the aryl and heteroaryl can have a substituent selected from the group consisting of C1-8 alkyl, C1-8 alkyl substituted with halogen, C1-8 alkoxy, C1-8 alkoxy substituted with halogen, C2-8 alkoxycarbonyl, formyl, carboxyl, halogen, hydroxyl, nitro, cyano, amino, C6-10 aryl, and C6-10 aryloxy;
• R2 is cyano, nitro, formyl, carboxyl, carbamoyl, or C2-8 alkoxycarbonyl;
• X is oxygen, —N(R3)—, or —S(O)n—, and R3 is a hydrogen, C1-8 alkyl, or the group mentioned above for R1, or R1 and R3 are combined to form morpholinyl, thiomorpholinyl, or piperazinyl, and n is an integer of 0 to 2;
• and
• Y is oxygen, sulfur, or NH.

A method for overcoming anti-cancer chemotherapeutic drug resistance comprising contacting a chemotherapeutic drug-resistant cell with an agent containing a compound having the following formula (II) or a salt thereof as an active ingredient for overcoming anti-cancer chemotherapeutic drug resistance:

• wherein R1 is C6-10 aryl or heteroaryl in which the aryl and heteroaryl can have a substituent selected from the group consisting of C1-8 alkyl, C1-8 alkyl substituted with halogen, C1-8 alkoxy, C1-8 alkoxy substituted with C1-8 alkoxy, C2-8 alkoxycarbonyl, formyl, carboxyl, halogen, hydroxyl, nitro, cyano, amino, C6-10 aryl, and C6-10 aryloxy;
• R2 is cyano, nitro, formyl, carboxyl, carbamoyl, or C2-8 alkoxycarbonyl;
• R3 is hydroxyl, amino, carboxyl, mercapto, OR4, or NHR5, and each of R4 and R5 is C1-8 alkyl or C1-8 alkyl substituted with a group or atom selected from the group consisting of halogen, hydroxyl, nitro, cyano, amino, C6-10 aryl, and C6-10 aryloxy;
• X is oxygen, —N(R6)—, or —S(O)n—, and
• R6 is a hydrogen, C1-8 alkyl, or the group mentioned above for R1, and n is an integer of 0 to 2;
• and
• Y is oxygen or sulfur.