Inactivation of ABL kinases suppresses non–small cell lung cancer metastasis
Jing Jin Gu, Clay Rouse, Xia Xu, Jun Wang, Mark W. Onaitis, Ann Marie Pendergast
Jing Jin Gu, Clay Rouse, Xia Xu, Jun Wang, Mark W. Onaitis, Ann Marie Pendergast
View: Text | PDF
Research Article Cell biology Oncology

Inactivation of ABL kinases suppresses non–small cell lung cancer metastasis

Abstract

Current therapies to treat non–small cell lung carcinoma (NSCLC) have proven ineffective owing to transient, variable, and incomplete responses. Here we show that ABL kinases, ABL1 and ABL2, promote metastasis of lung cancer cells harboring EGFR or KRAS mutations. Inactivation of ABL kinases suppresses NSCLC metastasis to brain and bone, and other organs. ABL kinases are required for expression of prometastasis genes. Notably, ABL1 and ABL2 depletion impairs extravasation of lung adenocarcinoma cells into the lung parenchyma. We found that ABL-mediated activation of the TAZ and β-catenin transcriptional coactivators is required for NSCLC metastasis. ABL kinases activate TAZ and β-catenin by decreasing their interaction with the β-TrCP ubiquitin ligase, leading to increased protein stability. High-level expression of ABL1, ABL2, and a subset of ABL-dependent TAZ- and β-catenin–target genes correlates with shortened survival of lung adenocarcinoma patients. Thus, ABL-specific allosteric inhibitors might be effective to treat metastatic lung cancer with an activated ABL pathway signature.

Authors

Jing Jin Gu, Clay Rouse, Xia Xu, Jun Wang, Mark W. Onaitis, Ann Marie Pendergast

×

Figure 5

ABL kinases promote β-catenin and TAZ protein abundance, nuclear translocation, and downstream signaling.

Options: View larger image (or click on image) Download as PowerPoint
ABL kinases promote β-catenin and TAZ protein abundance, nuclear translo...
(A and B) Gene set enrichment analysis of WNT (A) and TAZ (B) signature genes using RNAseq data from PC9 and PC9M cells treated with or without GNF5 or transduced with either scrambled (SCR) or ABL1/ABL2-specific (AA) shRNAs as indicated. (C and D) Endogenous β-catenin (C) and TAZ (D) activities in PC9 cells with or without GNF5 treatment was analyzed using luciferase-reporter assays and normalized to β-galactosidase activity. Data are represented as mean ± SEM. The P values were determined by Student’s t test (control n = 6, GNF5 n = 6). (E) PC9 cells were treated with or without GNF5 (left panel), transduced with either SCR or AA shRNAs (middle panel), or transduced with either vector control or active ABL2 (ABL2-PP, right panel). Western blots were probed with the indicated antibodies. (F) PC9 cells were pretreated with or without GNF5 for 1 hour followed by stimulation with WNT3A (100 ng/ml) for 5 hours. Cell lysates were fractionated into cytosolic and nuclear fractions, and TAZ and β-catenin localization was probed by Western blotting. For cytosolic β-catenin and TAZ samples, shorter exposure times are shown. Lamin A (nuclear marker) and tubulin (cytosolic marker) were used to assess the purity of the fractionation procedure. The nuclear fraction was quantified using Fiji ImageJ software. Relative protein intensity is shown. (G–I) PC9 cells pretreated with or without GNF5 for 1 hour (G) or transduced with SCR or AA shRNAs (H) and H460 cells pretreated with or without GNF5 for 1 hour (I) were stimulated without (–) or with WNT3A (W, 100 ng/ml) for 5 hours or LPA (L, 1 μM) for 4 hours. WNT and TAZ downstream target proteins were analyzed by Western blotting with the indicated antibodies. Samples were run contemporaneously in several parallel gels. EDN1, CyR61, and TNC proteins were analyzed from the culture supernatant. ABL kinase activity was detected by blotting for p-CrkL; tubulin and actin were used as loading controls.