Inhibitors of the PI3-kinase/Akt pathway induce mitotic catastrophe in non-small cell lung cancer cells.
Non-small cell lung cancer cells (NSCLC) are more resistant to anticancer treatment as compared with other types of cancer cells. Recently (Hemström et al., Exp Cell Res 2005;305:200-13) we showed that apoptosis of U1810 NSCLC cells induced by the staurosporine analog PKC 412 correlated with inhibition of Akt and ERK1/2, suggesting the involvement of these kinases in cell survival. Here we investigated the contribution of the PI3-kinase/Akt and MEK/ERK pathways to survival of NSCLC cells. The two signaling pathways were studied by using different combinations of the PI3-kinase inhibitors LY-294002 and wortmannin, the Akt activator Ro 31-8220, the MEK inhibitor PD 98059 and PKC 412. PI3-kinase inhibitors induced apoptosis-like death in U1810 cells. H157 cells in general were relatively resistant to PI3 kinase/Akt inhibitors yet these compounds sensitized cells to the DNA-damaging drug VP-16, while Ro 31-8220 could not. PD 98059 only had a sensitizing effect on H157 cells when combined with PI3-kinase inhibition and VP-16. Morphological data indicated that LY-294002 and PKC 412 induced cell death at anaphase and metaphase, respectively, suggesting death by mitotic catastrophe. Analyzes of cells blocked in G2/M-phase by nocodazol revealed that LY-294002 increased, while PKC 412 decreased histone H3 phosphorylation, suggesting that LY-294002 allowed, while PKC 412 inhibited cells to leave M-phase. Flow cytometric analysis of cell cycle distribution demonstrated that LY-294002 allowed cells to leave G2/M phase, while PKC 412 inhibited cytokinesis, resulting in formation of multinucleated cells. These results indicate that sensitization of NSCLC cells by PI3-kinase inhibition involves interplay between cell cycle regulation, mitotic catastrophe and apoptosis.
Hemström
Therese H
TH
Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
Sandström
Margareta
M
Zhivotovsky
Boris
B
D000730:Androstadienes / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005047:Etoposide / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects*; D009025:Morpholines / Q000494:pharmacology; D015739:Nocodazole / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects; D019311:Staurosporine / Q000031:analogs & derivatives / Q000494:pharmacology; D000077191:Wortmannin
D000730:Androstadienes; D000970:Antineoplastic Agents; D002867:Chromones; D004791:Enzyme Inhibitors; D005047:Etoposide; D005419:Flavonoids; D007211:Indoles; D020930:MAP Kinase Kinase Kinases; D009025:Morpholines; D015739:Nocodazole; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D019311:Staurosporine; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C059539:midostaurin; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; C064758:Ro 31-8220