Development and characterisation of a panel of phosphatidylinositide 3-kinase – mammalian target of rapamycin inhibitor resistant lung cancer cell lines

Abstract

The PI3K-mTOR pathway is involved in regulating all hallmarks of cancer, and is often dysregulated in NSCLC, making it an attractive therapeutic target in this setting. Acquired resistance to PI3K-mTOR inhibition is a major hurdle to overcome in the success of PI3K-mTOR targeted agents. H460, A549, and H1975 resistant cells were generated by prolonged treatment in culture with Apitolisib (GDC-0980), a dual PI3K-mTOR inhibitor over a period of several months, from age-matched parent cells. Resistance was deemed to have developed when a log fold difference in IC50 had been achieved. Resistant cell lines also exhibited resistance to another widely investigated PI3K-mTOR dual inhibitor; Dactolisib (BEZ235). Cell lines were characterised at the level of mRNA (expression array profiling expression of >150 genes), miRNA (expression array profiling of 2100 miRNAs), protein (bottoms-up label-free mass spectrometry) and phosphoprotein (expression array profiling of 84 phospho/total proteins). Key alterations were validated by qPCR and Western blot. H1975 cells were initially most sensitive to Apitolisib (GDC-0980), but developed resistance more quickly than the other cell lines, perhaps due to increased selective pressure from the impressive initial effect. In-depth molecular profiling suggested epithelial-mesenchymal transition (EMT) may play a role in resistance to PI3K-mTOR dual inhibition in NSCLC.

Identification of Two Kinase Inhibitors with Synergistic Toxicity with Low-Dose Hydrogen Peroxide in Colorectal Cancer Cells In vitro

“…Notably, this substance is already being used as a chemotherapeutic agent in HIPEC [153,154]. However, its application is often limited by resistances to rapamycin [146,155].…”

PIM kinase inhibition: co-targeted therapeutic approaches in prostate cancer

“…66 However, many have exhibited issues with toxicity or resistance due to compensatory mechanisms and feedback loops with closely related signaling pathways, and co-targeted inhibition approaches have been gaining popularity in preclinical studies. [67][68][69][70] Thus, PIM and PI3K co-targeting may be a viable approach owing to the overlap between those pathways, the proven PIMinduced resistance to PI3K inhibition 35 and the reported successful synergism that results when both are used. 71 Synergy between inhibitors could allow the use of lower therapeutic doses to achieve the same clinical effect, thus potentially reducing treatment toxicity and improving patient quality of life.…”

BEZ235 Increases the Sensitivity of Hepatocellular Carcinoma to Sorafenib by Inhibiting PI3K/AKT/mTOR and Inducing Autophagy

“…Oral administration of BEZ235 has a good anticancer effect on nude mouse xenograft models, without significant side effects [ 17 ]. BEZ235 also has had a good therapeutic effect against breast cancer, prostate cancer, lung cancer, and myeloid leukemia [ 18 – 21 ].…”