AXL Inactivation Inhibits Mesothelioma Growth and Migration via Regulation of p53 Expression

Abstract

Malignant mesothelioma is a locally aggressive and highly lethal neoplasm. Dysregulation and activation of Gas6/AXL tyrosine kinase signaling are associated with mesothelioma progression, but the mechanisms of these AXL tumorigenic roles are poorly understood. p53 mutants in lung carcinoma upregulate AXL expression by binding and acetylating the AXL promoter. Although TP53 mutations are uncommon in mesothelioma, we hypothesized that these tumors might have alternative feedback mechanisms between AXL and p53. In the current report, we investigated AXL regulation of TP53 transcription, expression, and biological function in mesothelioma. AXL expression was stronger in mesothelioma than most of the other tumor types from the TCGA gene expression profile dataset. AXL knockdown by shRNA induced wild-type and mutant p53 expression in mesothelioma cell lines, suggesting that AXL pro-tumorigenic roles result in part from the suppression of p53 function. Likewise, induced AXL inhibited expression of wild type p53 in COS-7 cells and 293T cells. Immunofluorescence staining showed nuclear colocalization of AXL and p53; however, association of AXL and p53 was not demonstrated in immunoprecipitation complexes. The AXL effects on p53 expression resulted from the inhibition of TP53 transcription, as demonstrated by qRT-PCR after AXL silencing and TP53 promotor dual luciferase activity assays. Chromatin immunoprecipitation-qPCR and sequencing showed that AXL bound to the initial 600 bp sequence at the 5′ end of the TP53 promoter. AXL inhibition (shRNA or R428) reduced mesothelioma cell viability, migration, and invasion, whereas TP53 shRNA knockdown attenuated antiproliferative, migration, and invasive effects of AXL silencing or AXL inactivation in these cells. These studies demonstrate a novel feedback regulation loop between AXL and p53, and provide a rationale for mesothelioma therapies targeting AXL/p53 signaling.

Single-cell RNA sequencing reveals microenvironment context-specific routes for epithelial-mesenchymal transition in pancreas cancer cells

“…Nuclear AXL has been observed in various carcinomas, including schwannoma, melanoma, and mesothelioma (36-39); however, there is still more to interrogate regarding the function of nuclear AXL, especially in relation to EMT. One study identified in mesothelioma that there was nuclear colocalization of AXL and p53, and that AXL can bind to the TP53 promoter to suppress expression (39). Several AXL inhibitors are in clinical trials for advanced solid tumors, colorectal cancer, non-small cell lung cancer, and other diseases (ClinicalTrials.gov).…”

YB‐1 regulates mesothelioma cell migration via snail but not EGFR, MMP1, EPHA5 or PARK2

“…Multiple signaling proteins have been shown to impact PM migration. These include, for instance, the receptor tyrosine kinase (RTK) family member AXL [ 31 ], the RTK family ligands FGF2 and EGF [ 26 ], the TGFβ family members activin A and B [ 32 , 33 ] and the sheddase ADAM10 [ 34 ]. Here we demonstrate that YB‐1 is a key player in PM cell motility, which is in line with its role in several other malignancies including melanoma [ 35 ], sarcoma [ 36 ] and lung adenocarcinoma [ 37 ].…”

Combined Analysis of RNA Sequence and Microarray Data Reveals a Competing Endogenous RNA Network as Novel Prognostic Markers in Malignant Pleural Mesothelioma

“…Interestingly, some of these genes out of the models were also directly associated with the MPM, which were mainly regarded as potential therapeutic targets, including CHEK1, DNMT3B, AXL, PAPPA, and miR-302b. Previous studies suggested that these genes are involved in the multiple antineoplastic processes of MPM, such as relief of chemo-and radioresistance, anti-proliferation, inhibition of growth and migration, and induction of apoptosis (31,(43)(44)(45)(46)(47)(48). Only two small-molecule drugs aiming to target the identified genes have been preliminarily evaluated, including palbociclib targeting CDK6 and AZD1775 targeting WEE1.…”