Disclosed is a compound represented by the Structural Formula (1); Y is a covalent bond, a phenylene group or a substituted or unsubstituted straight chained hydrocarbyl group In addition, Y, taken together with both >C=Z groups to which it is bonded, is a substituted or unsubstituted aromatic group. Preferably, Y is a covalent bond or -C(R 7 R 8 )-. R 1 and R 2 are independently an aryl group or a substituted aryl group, R 3 and R 4 are independently -H, an aliphatic group, a substituted aliphatic group, an aryl group or a substituted aryl group. R 5 -R 6 are independently -H, an aliphatic group, a substituted aliphatic group, an aryl group or a substituted aryl group. R 7 and R 8 are each independently -H, an aliphatic or substituted aliphatic group, or R 7 is -H and R 8 is a substituted or unsubstituted aryl group, or, R 7 and R 8 , taken together, are a C2-C6 substituted or unsubstituted alkylene group. Z is =O or =S. Also disclosed are pharmaceutical compositions comprising the compound of the present invention and a pharmaceutically acceplable carrier or diluent. Also disclosed is a method of treating a subject with cancer by administering to the subject a compound of Structural Formula (I) in combination with taxol or an analog of taxol.