NDR2 kinase contributes to cell invasion and cytokinesis defects induced by the inactivation of RASSF1A tumor-suppressor gene in lung cancer cells

Abstract

Background RASSF1A, a tumor suppressor gene, is frequently inactivated in lung cancer leading to a YAP-dependent epithelial-mesenchymal transition (EMT). Such effects are partly due to the inactivation of the anti-migratory RhoB GTPase via the inhibitory phosphorylation of GEF-H1, the GDP/GTP exchange factor for RhoB. However, the kinase responsible for RhoB/GEF-H1 inactivation in RASSF1A-depleted cells remained unknown. Methods NDR1/2 inactivation by siRNA or shRNA effects on epithelial-mesenchymal transition, invasion, xenograft formation and growth in SCID−/− Beige mice, apoptosis, proliferation, cytokinesis, YAP/TAZ activation were investigated upon RASSF1A loss in human bronchial epithelial cells (HBEC). Results We demonstrate here that depletion of the YAP-kinases NDR1/2 reverts migration and metastatic properties upon RASSF1A loss in HBEC. We show that NDR2 interacts directly with GEF-H1 (which contains the NDR phosphorylation consensus motif HXRXXS/T), leading to GEF-H1 phosphorylation. We further report that the RASSF1A/NDR2/GEF-H1/RhoB/YAP axis is involved in proper cytokinesis in human bronchial cells, since chromosome proper segregation are NDR-dependent upon RASSF1A or GEF-H1 loss in HBEC. Conclusion To summarize, our data support a model in which, upon RASSF1A silencing, NDR2 gets activated, phosphorylates and inactivates GEF-H1, leading to RhoB inactivation. This cascade induced by RASSF1A loss in bronchial cells is responsible for metastasis properties, YAP activation and cytokinesis defects. Electronic supplementary material The online version of this article (10.1186/s13046-019-1145-8) contains supplementary material, which is available to authorized users.

RASSF1A inhibits PDGFB-driven malignant phenotypes of nasopharyngeal carcinoma cells in a YAP1-dependent manner

“…Epigenetic silencing of RASSF1A results in constitutive nuclear YAP11 accumulation, which increases the extracellular matrix deposition and enhances stem-like characteristics 39 . Consistent with previous studies 40,41 , our study confirmed that RASSF1A depletion induced YAP1 nuclear translocation and triggered the expression of its target genes. Nuclear YAP1 is believed to activate TEAD transcriptional activity and induce the expression of a broad range of cytokines 42 .…”

Role of the YAP-1 Transcriptional Target cIAP2 in the Differential Susceptibility to Chemotherapy of Non-Small-Cell Lung Cancer (NSCLC) Patients with Tumor RASSF1A Gene Methylation from the Phase 3 IFCT-0002 Trial

“…Moreover, exogenous RASSF1A expression caused a slight decrease in cell proliferation in H1299 cells ( Figure 4B) and A549 cells ( Figure 4C), the difference achieved being statistically significant only in A549 cells ( Figure 4C). This reflects the necessity of appropriate RASSF1A levels for efficient cell proliferation [5,32]. To the authors' surprise, in both H1299 and A549 cells, a single IAP-2 knockdown or a combined IAP-2 knockdown with RASSF1A re-expression caused a modest but significant reduction in cell proliferation ( Figure 4B-C).…”

“…Additionally, a worse median OS was observed in patients with methylated RASSF1A treated with gemcitabine (30.3 months) compared to those treated with paclitaxel (70 months) [3]. These prognostic values of RASSF1A gene methylation were supported by data that demonstrated that RASSF1A restricts epithelial-mesenchymal transition (EMT) and cell invasion by controlling Yes-associated protein (YAP) nuclear shuttling and RhoB-regulated cytoskeletal remodeling process [4,5]. As such, RASSF1A inactivation favors the acquisition of a metastatic phenotype that explains these patients.…”

“…The authors have previously demonstrated that the loss of RASSF1A expression leads to the inappropriate activity of YAP, the subcellular localization of which becomes preferentially nuclear and coincides with an increase in the transcription of several target genes [4,5,28]. Some IAPs, proteins acting as negative apoptosis regulators by inhibiting the activity of several caspases [29], could also be the transcriptional targets of YAP as shown in drosophila [13].…”

RASSF1A, puppeteer of cellular homeostasis, fights tumorigenesis, and metastasis—an updated review

“…RASSF1A depletion is notably associated with upregulation of Rac1 activity 46 , and direct interaction of RASSF1A with RhoA causes the suppression of RhoA transforming activity 71 . RASSF1A also modulates the activity of RhoB GTPase, which functions as RhoA/RhoC antagonists 72 , through fine-tuning GEF-H1 activity by inducing its phosphorylation via NDR2 kinase 56,73 . More recently, Rheb, a Ras-related small GTPase, was shown to form a complex with RASSF1A to coordinate Hippo and TOR signaling 74 .…”