Potent induction of apoptosis in human hepatoma cell lines by targeted cytotoxic somatostatin analogue AN-238.
OBJECTIVE
The efficacy of a targeted cytotoxic hybrid somatostatin analogue AN-238 and of its superactive radical 2-pyrrolinodoxorubicin (AN-201) to induce apoptosis of HepG2 and Hep3B human hepatoma cell lines were studied. AN-238 was designed to selectively target tumor cells expressing somatostatin receptor subtypes (sst(s)). Its effects on HepG2 or Hep3B cells displaying or lacking tumor suppressor p53, respectively, were compared. Normal rat isolated hepatocytes were also tested.


METHODS
sst(s) were characterized by binding assays and RT-PCR. Cytotoxicity was quantified by flow cytometry. DNA fragmentation was studied by gel electrophoresis, PARP cleavage by Western blot and ROS formation using fluorescent probes.


RESULTS
Specific binding of iodinated RC-160 to HepG2 and Hep3B cells, and its displacement by AN-238 was characterized. mRNA for hsst(2A) was found in both cell lines. Flow cytometry showed a stronger effect of AN-238 than AN-201 to induce sub-G1 phase. DNA fragmentation, nuclear bodies, and PARP cleavage were observed. In addition, AN-238 increased formation of ROS more potently than AN-201. However, no inductions of DNA fragmentation by AN-201 or AN-238 were observed on rat hepatocytes.


CONCLUSIONS
Our results indicate that, in liver cancer, the cytotoxic somatostatin analogue AN-238 is a powerful agent that can induce apoptosis, through sst(s) and independently of p53.
Lasfer
Malika
M
INSERM Unit 481, Faculté de Médecine Xavier Bichat, IFR 02, 16 rue Henri Huchard, BP 416, 75870 Paris Cedex 18, France.
Vadrot
Nathalie
N
Schally
Andrew V
AV
Nagy
Attila
A
Halmos
Gabor
G
Pessayre
Dominique
D
Feldmann
Gérard
G
Reyl-Desmars
Florence J
FJ
D017209:Apoptosis / Q000187:drug effects*; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D003603:Cytotoxins / Q000633:toxicity*; D017931:DNA Primers; D004317:Doxorubicin / Q000031:analogs & derivatives / Q000633:toxicity*; D006801:Humans; D008113:Liver Neoplasms; D011758:Pyrroles / Q000633:toxicity*; D017481:Receptors, Somatostatin / Q000037:antagonists & inhibitors*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013004:Somatostatin / Q000235:genetics
C110845:AN 238; D003603:Cytotoxins; D017931:DNA Primers; D011758:Pyrroles; D017481:Receptors, Somatostatin; D013004:Somatostatin; D004317:Doxorubicin