Effects of anandamide on polyamine levels and cell growth in human colon cancer cells.
BACKGROUND
Anandamide (AEA) is an endogenous agonist for cannabinoid receptor CB1-R and seems to be involved in the control of cancer growth. Polyamines are compounds that play an important role in cell proliferation and differentiation. Our aim was to investigate the effect of AEA on the polyamine levels (putrescine, spermidine and spermine) and cell growth of three human colon cancer cell lines, positive for CB1-R.


METHODS
After AEA treatment of DLD-1, HT-29 and SW620 cells, polyamine analysis was performed by high-performance liquid chromatography (HPLC) and cell growth was measured by 3-(4,5 di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. CB1 gene expression was determined using reverse transcription and polymerase chain reaction (RT-PCR).


RESULTS
AEA significantly reduced polyamine levels and cell proliferation dose-dependently when the tested cell lines were exposed for 24 h and 48 h. This inhibitory effect was mediated by CB1-R, since SR 1411716A, a selective CB-1 receptor antagonist, was able to entirely antagonize the effect of AEA. CB1-R mRNA levels were enhanced after AEA treatment in DLD-1 cells, whereas no induction was found in HT-29 and SW620 cells.


CONCLUSIONS
It appears that mechanisms by which AEA may affect growth of colon cancer cells involve a decrease in cell proliferation rate by reducing the polyamine levels.
Linsalata
Michele
M
Laboratory of Biochemistry, National Institute for Digestive Diseases, Via Turi 27, 70013 Castellana Grotte, Bari, Italy.
Notarnicola
Maria
M
Tutino
Valeria
V
Bifulco
Maurizio
M
Santoro
Antonietta
A
Laezza
Chiara
C
Messa
Caterina
C
Orlando
Antonella
A
Caruso
Maria Gabriella
MG
D001095:Arachidonic Acids / Q000494:pharmacology*; D015317:Biogenic Polyamines / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D048708:Cell Growth Processes / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids; D015870:Gene Expression / Q000187:drug effects; D019073:HT29 Cells; D006801:Humans; D053284:Polyunsaturated Alkamides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism
D001095:Arachidonic Acids; D015317:Biogenic Polyamines; D063388:Endocannabinoids; D053284:Polyunsaturated Alkamides; D012333:RNA, Messenger; D043884:Receptor, Cannabinoid, CB1; C078814:anandamide