Three-Kinase Inhibitor Combination Recreates Multi-Pathway Effects of a Geldanamycin Analog on Hepatocellular Carcinoma Cell Death

Multi-target compounds that act on a diverse set of regulatory pathways are emerging as a therapeutic approach for a variety of cancers. Toward a more specified use of this approach, we hypothesize that the desired efficacy can be recreated in terms of a particular combination of relatively more specific (i.e., ostensibly single-target) compounds. We test this hypothesis for the geldanamycin analog 17AAG in hepatocellular carcinoma (HCC) cells, measuring critical phosphorylation levels that indicate the kinase pathway effects correlating with apoptotic responsiveness of the Hep3B cell line in contrast to the apoptotic resistance of the Huh7 cell line. A principal components analysis constructed from time-course measurements of 7 phospho-protein signaling levels identified modulation of the AKT, IKK and STAT3 pathways by 17AAG treatment as most important for distinguishing these cell-specific death responses. The analysis correctly suggested from 17AAGinduced effects on these phospho-protein levels that the FOCUS cell line would show apoptotic responsiveness similarly to Hep3B. The PCA also guided the inhibition of three critical pathways and rendered Huh7 cells responsive to 17AAG. Strikingly, in all three HCC lines the three-inhibitor combination alone exhibited similar or greater efficacy to 17AAG. We conclude that: (a) the principal components analysis captures and clusters the multi-pathway phospho-protein timecourses with respect to their 17AAG-induced apoptotic responsiveness;...(passage deleted)... (b) we can recreate, in a more specified manner, the cellular responses of a prospective multi-target cancer therapeutic.