Apoptosis of human carcinoma cells in the presence of inhibitors of glycosphingolipid biosynthesis: I. Treatment of Colo-205 and SKBR3 cells with isomers of PDMP and PPMP.
Apoptosis, or programmed cell death, plays an important role in many physiological and diseased conditions. Induction of apoptosis in cancer cells by anti-cancer drugs and biosynthetic inhibitors of cells surface glycolipids in the human colon carcinoma cells (Colo-205) are of interest in recent years. In our present studies, we have employed different stereoisomers of PPMP and PDMP (inhibit GlcT-glycosyltransferase (GlcT-GLT)) to initiate apoptosis in Colo-205 cells grown in culture in the presence of (3)H-TdR and (3)H/or (14)C-L-Serine. Our analysis showed that the above reagents (between 1 to 20 microM) initiated apoptosis with induction of Caspase-3 activities and phenotypic morphological changes in a dose-dependent manner. We have observed an increase of radioactive ceramide formation in the presence of a low concentration (1-4 microM) of these reagents in these cell lines. However, high concentrations (4-20 microM) inhibited incorporation of radioactive serine in the higher glycolipids. Colo-205 cells were treated with L-threo-PPMP (0-20 microM) and activities of different GSL: GLTs were estimated in total Golgi-pellets. The cells contained high activity of GalT-4 (UDP-Gal: LcOse3Cer beta 1-4galactosyltransferase), whereas negligible activity of GalT-3 (UDP-Gal: GM2 beta 1-3galactosyltransferase) or GM2-synthase activity of the ganglioside pathway was detected. Previously, GLTs involved in the biosynthetic pathway of SA-Le(x) formation had been detected in these colon carcinoma (or Colo-205) cells (Basu M et al. Glycobiology 1, 527-35 (1991)). However, during progression of apoptosis in Colo-205 cells with increasing concentrations of L-PPMP, the GalT-4 activity was decreased significantly. These changes in the specific activity of GalT-4 in the total Golgi-membranes could be the resultant of decreased gene expression of the enzyme.
Basu
Subhash
S
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA. sbasu@nd.edu
Ma
Rui
R
Mikulla
Brian
B
Bradley
Mathew
M
Moulton
Christopher
C
Basu
Manju
M
Banerjee
Sipra
S
Inokuchi
Jin-ichi
J
D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D002250:Carbon Radioisotopes; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002518:Ceramides / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006028:Glycosphingolipids / Q000096:biosynthesis*; D006801:Humans; D008614:Meperidine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D009025:Morpholines / Q000737:chemistry* / Q000494:pharmacology* / Q000627:therapeutic use; D009369:Neoplasms / Q000188:drug therapy / Q000473:pathology*; D012694:Serine / Q000378:metabolism; D013237:Stereoisomerism
D000970:Antineoplastic Agents; D002250:Carbon Radioisotopes; D002518:Ceramides; D004791:Enzyme Inhibitors; D006028:Glycosphingolipids; D009025:Morpholines; C026733:4-propionyloxy-4-phenyl-N-methylpiperidine; D012694:Serine; C033110:RV 538; D008614:Meperidine; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases