Compositions and methods for treating cancer

A method for treating cancer in a subject in need thereof comprising:

• administering to the subject therapeutically effective amounts of a PP2A activator and a protein kinase inhibitor, wherein the cancer is characterized by cancer cells in which PP2A has reduced activity, the PP2A activator comprises a compound of formula (IV):
• wherein:
• B is selected from the group consisting of:
• direct bond, —O—, (CH2—O), —(O—CH2)—, —C(═O)N(CH3)— and —N(CH3)C(═O)—;
• A is selected from N and CH;
• T is a benzene ring or a five or six membered heteroaromatic ring;
• U is a benzene ring or a five or six membered heteroaromatic ring;
• n is zero, 1 or 2;
• R1, R2, R3 and R4 are chosen independently from H, OH, halogen, cyano, nitro, (C1-C3)alkylamino, (C1-C3)dialkylamino, (C1-C3)acylamino, (C1-C3)alkylsulfonyl, (C1-C3)alkylthio, (C1-C3)alkyl, (C1-C3)haloalkyl, (C1-C3)haloalkoxy, —CC(═O)O(C1-C3)alkyl, and (C1-C3)alkoxy;
• R5 and R6 are chosen independently from H, halogen, cyano, nitro, azido, (C1-C3)haloalkyl, (C1-C3)haloalkoxy, and (C1-C3)haloalkylthio;
• and
• the protein kinase inhibitor inhibits phosphorylation of a catalytic subunit of PP2A;
• and
• wherein said cancer is selected from the group consisting of leukemia, prostate, endometrial and non-small cell lung cancer.