Resistance to multikinase inhibitor actions mediated by insulin like growth factor-1.
BACKGROUND
Blood platelet numbers are correlated with growth and aggressiveness of several tumor types, including hepatocellular carcinoma (HCC). We previously found that platelet lysates (hPLs) both stimulated HCC cell growth and migration, and antagonized the growth-inhibitory and apoptotic effects of Regorafenib, multikinase growth inhibitor, on HCC cell lines. We evaluated the effects of human insulin-like growth factor-1 (IGF1), a mitogen contained in platelets, on the Regorafenib-mediated growth inhibition.


METHODS
An Elisa kit was used to evaluate hPL IGF1 concentrations. The effects of IGF1 on cell proliferation were assessed with MTT assay and analysis of cell cycle progression. Apoptosis assays, scratch assay and Transwell assay were performed to measure apoptosis, cell migration and invasion respectively. Western blots were performed by standard protocols.


RESULTS
IGF1 antagonized growth inhibition exerted by Regorafenib on HCC cell lines. Moreover the mitogen blocked Regorafenib-induced apoptosis and decreased the rate of cell migration and invasion. The IGF1 effects were in turn antagonized by actions of a potent IGF1 receptor inhibitor, GSK1838705A, showing that the IGF1 receptor was involved in the mechanisms of IGF1-mediated blocking of Regorafenib action. GSK1838705A also partially blocked the effects of hPLs in antagonizing Regorafenib-mediated growth inhibition, showing that IGF1 was an important component of hPL actions.


CONCLUSIONS
These results show that IGF1 antagonized Regorafenib-mediated growth, migration and invasion inhibition, as well as the drug-mediated induction of apoptosis in HCC cells and reinforce the idea that microenvironmental factors can influence cancer drug actions.
Department Clinical Pathology, Laboratory of Cellular and Molecular Biology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013, Castellana Grotte, BA, Italy. catia.lippolis20@libero.it.
Catia
C
Lippolis
Department Clinical Pathology, Laboratory of Cellular and Molecular Biology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013, Castellana Grotte, BA, Italy. mgrefolo@libero.it.
Maria Grazia
MG
Refolo
Department Clinical Pathology, Laboratory of Cellular and Molecular Biology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013, Castellana Grotte, BA, Italy. dalessandro.rosalba@libero.it.
Rosalba
R
D'Alessandro
Department Clinical Pathology, Laboratory of Cellular and Molecular Biology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013, Castellana Grotte, BA, Italy. nicolacarella@gmail.com.
Nicola
N
Carella
Department Clinical Pathology, Laboratory of Cellular and Molecular Biology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013, Castellana Grotte, BA, Italy. caterina.messa@irccsdebellis.it.
Caterina
C
Messa
Department Clinical Pathology, Laboratory of Cellular and Molecular Biology, National Institute for Digestive Diseases, IRCCS "Saverio de Bellis", Via Turi 27, 70013, Castellana Grotte, BA, Italy. cavaldo@libero.it.
Aldo
A
Cavallini
Izmir Biomedicine and Genome Center, Dokuz Eylul University, Izmir, Turkey. brianicarr@hotmail.com.
Brian Irving
BI
Carr
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002465:Cell Movement; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D056945:Hep G2 Cells; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D009361:Neoplasm Invasiveness; D010671:Phenylurea Compounds / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D015398:Signal Transduction
D000970:Antineoplastic Agents; C583557:IGF1 protein, human; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors; D011725:Pyridines; C559147:regorafenib; D007334:Insulin-Like Growth Factor I