Impairment of the Pin1/E2F1 axis in the anti-proliferative effect of bortezomib in hepatocellular carcinoma cells.
BACKGROUND
The modest efficacy of available therapies for Hepatocellular carcinoma (HCC) indicates the need to develop novel therapeutic approaches. For the proteasome inhibitor Bortezomib (BZB), potentially attractive for HCC treatment, the mechanism of action is largely unknown. The BZB effect on E2Fs and the E2Fs control on the peptidylproline cis-trans isomerase (Pin1), prompted us to explore the BZB effect on the Pin1-E2F1 axis.


METHODS
The tumorigenic cell line HuH7 together with the non-tumorigenic cells IHH and the human pluripotent stem cell derived hepatocytes (hPSC-H), were used as cellular models of HCC and normal liver cells, respectively.


RESULTS
BZB reduces HuH7 growth as shown by cell counting, cell vitality test and cell cycle analysis; this is paralleled by the decrease of Pin1, E2F1, cyclin A2 and of the hyper-phosphorylated pRB. Pin1-E2F1 axis impairment justifies the anti-proliferative effect since Pin-E2F1 depletion decreases HuH7 growth while the over-expression rescues BZB-induced inhibition of proliferation. Moreover, Pin1-E2F1 promote HuH7 growth via the up-regulation of cyclin D1, cyclin E, cyclin A2, E2F2 and in part E2F3. Finally, in the control cells IHH and hPSC-H, BZB effect on cell vitality is not irrelevant, a fact correlated to the cellular proliferation rate. Thus, BZB effect on healthy liver tissue may not be entirely negligible hence caution should be exercised in its use in liver regeneration processes.


CONCLUSIONS
For the first time we prove the functional involvement of the Pin1-E2F1 axis in the anti-proliferative effect of BZB indicating Pin1-E2F as an attractive target to control HCC cell growth.
Department of Industrial Engineering and Information Technology, University of Trieste, V. Valerio 10, 34100 Trieste, Italy.
Rossella
R
Farra
Department of Life Sciences, University of Trieste, Via Giorgieri, 10, 34127 Trieste, Italy.
Barbara
B
Dapas
International Centre for Genetic Engineering and Biotechnology, Via E. Ramarini 32, 00016 Monterotondo Scalo, Rome, Italy.
Daniele
D
Baiz
Department of Industrial Engineering and Information Technology, University of Trieste, V. Valerio 10, 34100 Trieste, Italy.
Federica
F
Tonon
Department of Life Sciences, University of Trieste, Via Giorgieri, 10, 34127 Trieste, Italy.
Sara
S
Chiaretti
Department of Life Sciences, University of Trieste, Via Giorgieri, 10, 34127 Trieste, Italy; Laboratorio Nazionale CIB (LNCIB), Area Science Park, Trieste, Italy.
Giannino
G
Del Sal
Department of Life Sciences, University of Trieste, Via Giorgieri, 10, 34127 Trieste, Italy; Laboratorio Nazionale CIB (LNCIB), Area Science Park, Trieste, Italy.
Alessandra
A
Rustighi
Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy; Venetian Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy.
Nicola
N
Elvassore
Department of Medical, Surgery and Health Sciences, University of Trieste, Cattinara Hospital, Strada di Fiume 447, 34134, Trieste, Italy.
Gabriele
G
Pozzato
Department of Industrial Engineering and Information Technology, University of Trieste, V. Valerio 10, 34100 Trieste, Italy.
Mario
M
Grassi
Department of Life Sciences, University of Trieste, Via Giorgieri, 10, 34127 Trieste, Italy; Department of Medical, Surgery and Health Sciences, University of Trieste, Cattinara Hospital, Strada di Fiume 447, 34134, Trieste, Italy. Electronic address: ggrassi@units.it.
Gabriele
G
Grassi
D000069286:Bortezomib / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D050687:E2F1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*
D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D009363:Neoplasm Proteins; D000069286:Bortezomib; C000606846:PIN1 protein, human; D019696:Peptidylprolyl Isomerase
Cell cycle; E2F1; Huh7; Liver cancer; Pin1; Proteasome inhibitor