INVESTIGADORES
URTREGER Alejandro Jorge
congresos y reuniones científicas
Título:
The synthetic peptide CIGB-300 inhibits NF-kB affecting the survival and hemoresistance of NSCLC cell lines
Autor/es:
STÉFANO M. CIRIGLIANO; MARÍA INÉS DÍAZ BESSONE; CAROLINA FLUMIAN; DAMIAN E. BERARDI; SILVIO PEREA; ELISA D. BAL DE KIER JOFFE; HERNÁN FARINA; LAURA B. TODARO; ALEJANDRO J. URTREGER
Lugar:
Panama
Reunión:
Congreso; 7th Latin American Conference on Lung Cancer (LALCA 2016); 2016
Institución organizadora:
International Association for the Study of Lung Cancer (IASLC)
Resumen:
Background The CK2 Ser/Thr kinase has been historically linked with cancer. It is involved in cell proliferation, survival and apoptosis by modulating diverse signaling pathways, including Wnt and NF-kB among the most relevant.CIGB-300 is an antitumor peptide with a novel mechanism of action, capable of binding to CK2 substrates thus preventing the enzyme activity. NF-kB activation can reduce chemotherapy efficiency in lung cancer. We have determined that CIGB-300 inhibits NF-kB (p65) nuclear translocation. Also, CIGB-300 alters the ability of lung cancer cells to grow in a three-dimensional spheroid model. Method A cisplatin resistant cell line (A549-Rcisp) was developed by chronic administration during six months. Proteasome-selective activity was assessed with Proteasome-Glo? Assay (Promega). Cellular distribution of proteasome Alpha7/C8 subunit and CIGB-300 was visualized by confocal immunofluorescence. Pearson´s and Manders coefficients were measured with JACoP plugin for ImageJ. Biotin-labeled CIGB-300 was used to treat NCI-H125 spheroids at different time points and detected by immunohistochemistry. Results Nuclear p65 levels were highly increased after treating human NCI-H125 cells with cisplatin. When cells were treated with cisplatin plus CIGB-300, NF-kB activation was completely abolished. Therefore, the CIGB-300 effect on NF-kB signaling pathway prevails over cisplatin. This led us to evaluate the combined treatment in a chemoresistant setting. For this purpose we developed a cisplatin resistant A549 lung cancer cell line (A549-Rcisp). A549-Rcisp viability was 40% higher than parental cells, confirming the acquisition of cisplatin-resistance. Remarkably, A549-Rcisp showed a significant increase in CIGB-300 sensitivity as compared to the parental cell line. More on, only A549-Rcisp showed an increased p65 nuclear level after cisplatin treatment, suggesting that both cisplatin resistance and CIGB-300 sensitization might be linked to the NF-kB transcription factor.Given that NF-kB dimer stability is regulated by the proteasome-selective proteolysis of its inhibitory proteins, we studied the effect of CIGB-300 on this process. Surprisingly, we observed a significant increase on protease activities associated with the proteasome after 30 minutes of CIGB-300 treatment. More on, we observed high co-ocurrence between the CK2 substrate Alpha7/C8, a member of the proteasome alpha ring, and CIGB-300 (Pearson´s=0.82, M1=0.82, M2=0.65). Thus, the proteasome complex is a newly identified target of CIGB-300 that may be relevant for its mechanism of action and deserves further exploration to determine the association with the pathway perturbations that we have observed. Finally, as CIGB-300 inhibits 3D growth, we analyze whether it was able to affect spheroid compact structure that resembles in vivo avascular tumour conditions which makes drug-entry difficult. By immunohistochemistry we observed a fast and effective entrance of CIGB-300, detecting mark after 5 minutes of treatment. Complete spheroid penetration was reached at 60 minutes. Conclusion In conclusion, our results show that treatment with CIGB-300 negatively modulates several characteristics associated to malignant progression by affecting different signaling pathways. Moreover, its improved effectiveness in a chemoresistance model associated with NF-κB inhibition indicates that CIGB-300 may become a new strategy for lung cancer treatment.