The BH3-mimetic ABT-737 targets the apoptotic machinery in cholangiocarcinoma cell lines resulting in synergistic interactions with zoledronic acid.
OBJECTIVE
In TFK-1 and EGI-1 cholangiocarcinoma cell lines, zoledronic acid (ZOL) determines an S-phase block without apoptosis. Here, we investigated the occurrence of apoptosis stigmata when ZOL is associated to the BH3-mimetic ABT-737.


METHODS
In EGI-1 and TFK-1 cholangiocarcinoma cell lines untreated or treated with ABT-737 alone or in combination with ZOL, the pro-survival protein's pattern (BCL-2, BCL-XL, MCL-1, HSP72, HSP27) was investigated by biochemical criteria along with the occurrence of mitochondrial damage evaluated by cytofluorimetric analysis using a cationic dye.


RESULTS
ABT-737 induced growth inhibition and significantly affected the colony-forming ability of both EGI-1 and TFK-1 cells. However, activated PARP-1 or/and caspase-3 cleavage (apoptosis markers) were detected only at the highest ABT-737 concentrations used. Combined treatment showed synergistic effect by converting the predominant cytostatic effect of ZOL into a cytotoxic one as shown by striking increment of mitochondrial harmed cells along with PARP-1 activation and caspase-3 cleavage.


CONCLUSIONS
The lack of apoptosis following ZOL treatment in these cholangiocarcinoma cell lines appears to be multifactorial and could be ascribed to the large constitutive expression of pro-survival proteins. The efficacy of ZOL treatment requires a concomitant unleashing of apoptosis using a selective BH3-mimetic as ABT-737. The rational targeting of specific components of the apoptotic pathway may appear a useful approach to improve the treatment of refractory or relapsed cholangiocarcinoma. Combined treatment could be further explored in in vivo tumor model of cholangiocarcinoma.
Romani
Antonello A
AA
Dipartimento di Scienze Chirurgiche, Sezione di Clinica Chirurgica e dei Trapianti d'Organo, Università degli Studi di Parma, Parma, Italy.
Desenzani
Silvia
S
Morganti
Marina M
MM
Baroni
Maria Cristina
MC
Borghetti
Angelo F
AF
Soliani
Paolo
P
D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001650:Bile Duct Neoplasms / Q000188:drug therapy / Q000473:pathology; D001653:Bile Ducts, Intrahepatic / Q000187:drug effects / Q000473:pathology; D001713:Biphenyl Compounds / Q000494:pharmacology*; D045744:Cell Line, Tumor; D018281:Cholangiocarcinoma / Q000188:drug therapy* / Q000473:pathology; D004164:Diphosphonates / Q000494:pharmacology*; D016503:Drug Delivery Systems; D004357:Drug Synergism; D005786:Gene Expression Regulation; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D009596:Nitrophenols / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D016196:S Phase / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology*; D000077211:Zoledronic Acid
C501332:ABT-737; D000970:Antineoplastic Agents; D001713:Biphenyl Compounds; D004164:Diphosphonates; D007093:Imidazoles; D009596:Nitrophenols; D010879:Piperazines; D013449:Sulfonamides; D000077211:Zoledronic Acid