Co-Targeting PIM Kinase and PI3K/mTOR in NSCLC

• Main Authors: Gillian Moore, Clara Lightner, Samira Elbai, Lauren Brady, Siobhan Nicholson, Ronan Ryan, Katie E. O’Sullivan, Kenneth J. O’Byrne, Carmen Blanco-Apiricio, Sinead Cuffe, Michael O’Neill, Susan Heavey, Stephen P. Finn, Kathy Gately
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Cancers
• Subjects: PIM kinase; PI3K-mTOR; c-Myc; drug resistance; NSCLC; tumor tissue explants
• Online Access: https://www.mdpi.com/2072-6694/13/9/2139

PIM kinases are constitutively active proto-oncogenic serine/threonine kinases that play a role in cell cycle progression, metabolism, inflammation and drug resistance. PIM kinases interact with and stabilize p53, c-Myc and parallel signaling pathway PI3K/Akt. This study evaluated PIM kinase expression in NSCLC and in response to PI3K/mTOR inhibition. It investigated a novel preclinical PI3K/mTOR/PIM inhibitor (IBL-301) in vitro and in patient-derived NSCLC tumor tissues. Western blot analysis confirmed PIM1, PIM2 and PIM3 are expressed in NSCLC cell lines and PIM1 is a marker of poor prognosis in patients with NSCLC. IBL-301 decreased PIM1, c-Myc, pBAD and p4EBP1 (Thr37/46) and peIF4B (S406) protein levels in-vitro and MAP kinase, PI3K-Akt and JAK/STAT pathways in tumor tissue explants. IBL-301 significantly decreased secreted pro-inflammatory cytokine MCP-1. Altered mRNA expression, including activated PIM kinase and c-Myc, was identified in Apitolisib resistant cells (H1975GR) by an IL-6/STAT3 pathway array and validated by Western blot. H1975GR cells were more sensitive to IBL-301 than parent cells. A miRNA array identified a dysregulated miRNA signature of PI3K/mTOR drug resistance consisting of regulators of PIM kinase and c-Myc (miR17-5p, miR19b-3p, miR20a-5p, miR15b-5p, miR203a, miR-206). Our data provides a rationale for co-targeting PIM kinase and PI3K-mTOR to improve therapeutic response in NSCLC.