A screen of shRNAs targeting tumor suppressor genes to identify factors involved in A549 paclitaxel sensitivity.

An shRNA tumor suppressor panel was screened using reverse infection of an A549 tumorigenic cell line and exposing it to a predetermined concentration of paclitaxel, an anticancer drug. The shRNAs targeting a positive control gene, MDR1, were found to effectively decrease mRNA levels and cause cells to become more sensitive to the chemotherapeutic drug. A set of genes were identified in the screen of a panel of tumor suppressors which, when down-regulated, were found to increase or decrease cell sensitivity in regards to treatment with paclitaxel. In many cases, there were multiple clones to a single gene that provided a positive result. The shRNAs targeting SMAD4, LZTS2, ST14 and VHL all increased the cell's sensitivity to paclitaxel. The loss of other tumor suppressors such as GLTSCR2, LATS1, NF1, PTEN, TP53 and WT1 induced a protective effect in the cell, making it more resistant to the effect of the drug. Further investigation of VHL mRNA levels after down-regulation with shRNA show a direct correlation between gene expression levels and paclitaxel sensitivity. This study credits the identified genes with the potential to act as prognostic biomarkers for use in genetic profiling, or even as targets in pathways of tumorigenesis yet to be fully understood.