Cellular uptake, intracelular transportation and degradation mechanism of the proapoptotic peptide CIGB-300 in sensitive and resistant tumor cell lines.

FERNANDO BENAVENT ACERO; YASSER PERERA; SILVIO E. PEREA; DANIEL F. ALONSO; DANIEL E. GOMEZ; HERNÁN G. FARINA

Bariloche

Simposio; The Second South American Symposium in Signal Transduction and Molecular Medicine.; 2012

SISTAM

We have previously demonstrated that a proapoptotic cyclic peptide CIGB-300, formerly known as P15-Tat, can be delivered into cells by the cell-penetrating peptide Tat. CIGB-300 was able to abrogate the CK2-mediated phosphorylation by direct binding to the conserved phosphoacceptor site on their substrates. Previous findings showed that CIGB-300 inhibits tumor cell proliferation in vitro and reduces tumor growth in vivo in cancer animal models. In this work, we studied the cellular uptake of the CIGB-300 in different sensitive and resistant tumor cells such as lung, prostate, leukemia and cervix cell lines. Internalization was studied at 37°C and 4°C to determine the involved mechanism (endocytosis or traslocation). Furthermore, we determined if the presence of metabolic inhibitors such as sodium azide and rotenone had effect on the CIGB-300 uptake in tumor cells. We also studied intracellular peptide trafficking pathways using caveolins and clathrins endocitic markers. Finally we determined the degradation mechanism of the CIGB-300 peptide in sensitive and resistant cell lines. Altogether, our data shows that there is a differential sensitivity to the CK2 inhibitor peptide by different tumor cell lines. Also, these results will help further understand how the CIGB-300 peptide inhibitor would exert its antitumoral action on the different tumor models evaluated.