Pharmaceutical compositions containing an effective amount of a ligand for GPR109 to decrease
intracellular cAMP levels of a subject in combination with an effective amount of
a DNA methyl
transferase inhibito to reduce or inhibit downregulation of GPR109 in the intestinal epithelial cells of the subject relative to a control are provided. It has been discovered that ligands for GPR109 can be used to treat one or more symptoms of
cancer, inflammatory disorders, and
diarrhea. Representative CPR 109 ligands include, but are not limited to
butyrate, β-hydroxybutyrate, nicotinic acid, acifran, and octanoate. Suitable
DNA methyl
transferase inhibitors include 5-azacytidine, 5-aza-2′-deoxytidine, 1-β-D-arabinfαmosyl-5-azacytosine and dihydro-5-azacytidine. Typically, the compositions are formulated to achieve a GPR 109 ligand serum
blood level of about 1 to about 1000 μM. The compositions are useful for the treatment of one or more symptoms of
cancer. Preferred cancers that can be treated using the disclosed compositions include, but are not limited to colon
cancer,
breast cancer and
leukemia. Methods for treating cancer, inflammatory disorders, and
diarrhea are also provided.