This invention provides a method for increasing apoptosis in a cancer cell comprising contacting the cancer cell with (a) gemcitabine and (b) C6-ceramide, sequentially or concomitantly, wherein the gemcitabine and C6-ceramide are in amounts such that the apoptosis induced by the combination of gemcitabine and C6-ceramide is greater than the apoptosis induced by contacting the cancer cell with either gemcitabine alone or C6-ceramide alone. This invention also provides a method of decreasing the size of a tumor, which method comprises contacting the tumor with (a) gemcitabine and (b) C6-ceramide, sequentially or concomitantly, wherein the gemcitabine and C6-ceramide are in amounts such that the decrease in tumor size induced by the combination of gemcitabine and C6-ceramide is greater than the decrease in tumor size induced by contacting the tumor with either gemcitabine alone or C6-ceramide alone. This invention further provides a pharmaceutical composition and a method for treating a subject afflicted with cancer.
