AXL is a predictor of poor survival and of resistance to anti-EGFR therapy in RAS wild-type metastatic colorectal cancer

• Published in: European journal of cancer (1990) Vol. 138; pp. 1 - 10
• Main Authors: Cardone, Claudia, Blauensteiner, Bernadette, Moreno-Viedma, Veronica, Martini, Giulia, Simeon, Vittorio, Vitiello, Pietro P., Ciardiello, Davide, Belli, Valentina, Matrone, Nunzia, Troiani, Teresa, Morgillo, Floriana, Zito Marino, Federica, Dentice, Monica, Nappi, Annarita, Boccaccino, Alessandra, Antoniotti, Carlotta, Cremolini, Chiara, Pietrantonio, Filippo, Prager, Gerald W., Normanno, Nicola, Maiello, Evaristo, Argiles, Guillem, Elez, Elena, Signoriello, Giuseppe, Franco, Renato, Falcone, Alfredo, Tabernero, Josep, Sibilia, Maria, Ciardiello, Fortunato, Martinelli, Erika
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-10-2020; Elsevier Science Ltd
• Subjects: Angiogenesis; Animals; Antiangiogenics; AXL; Axl protein; Biomarkers; Biotechnology; Cancer; Cell culture; Cell Line, Tumor; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms - chemistry; Colorectal Neoplasms - drug therapy; Colorectal Neoplasms - mortality; Colorectal Neoplasms - pathology; Datasets; Drug resistance; Drug Resistance, Neoplasm; EGFR resistance; Epidermal growth factor; Epidermal growth factor receptors; ErbB Receptors - antagonists & inhibitors; Gene expression; Genes, ras; Growth factors; Human performance; Humans; Immunohistochemistry; Medical prognosis; Mesenchyme; Metastases; Metastasis; Mice; Monoclonal antibodies; Mutation; Neoplasm Metastasis; Patients; Proto-Oncogene Proteins - analysis; RAS WT; Receptor Protein-Tyrosine Kinases - analysis; Ribonucleic acid; RNA; Survival; Targeted cancer therapy; Therapy; Transfection; Tumors; Xenograft Model Antitumor Assays; Xenografts; Xenotransplantation; NSCLC; OS; EGFR resistance; Colorectal cancer; CMS; 3-D; MSS; EGFR; GEO; moAb; PD; AXL; FFPE; mCRC; HNSCC; PFS; WT; RAS WT
• ISSN: 0959-8049; 1879-0852
• DOI: 10.1016/j.ejca.2020.07.010

RAS mutations are the only validated biomarkers in metastatic colorectal cancer (mCRC) for anti-epidermal growth factor receptor (EGFR) therapy. Limited clinical information is available on AXL expression, marker of epithelial to mesenchymal transition, in mCRC.
AXL was retrospectively assessed by immunohistochemistry in 307 patients. RAS wild-type (WT) patients (N = 136) received first-line anti-EGFR–based therapy; RAS mutant patients (N = 171) received anti-angiogenic–based regimens.
Preclinical experiments were performed using human RAS WT CRC cell lines and xenograft models. AXL RNA levels were assessed in a cohort of patients with available samples at baseline and at progression to anti-EGFR treatment and in the GSE5851 dataset.
AXL was expressed in 55/307 tumour tissues, correlating with worse survival in the overall population (AXL-positive, 23.7 months; AXL-negative, 30.8 months; HR, 1.455, P = 0.032) and in RAS WT patients (AXL-positive, 23.0 months; AXL-negative, 35.8 months; HR,1.780, P = 0.032). Progression-free survival (PFS) in the RAS WT cohort was shorter in the AXL-positive cohort (6.2 months versus 12.1 months; HR, 1.796, P = 0.013). Three-dimensional cultures obtained from a patient following anti-EGFR therapy resulted AXL-positive, showing resistance to anti-EGFR drugs and sensitivity to AXL inhibition. AXL transfection in CRC cell lines induced AXL overexpression and resistance to the EGFR blockade. At progression to cetuximab, 2/10 SW48-tumour xenograft mice showed AXL expression. Consistently, AXL RNA levels increased in 5/7 patients following anti-EGFR therapy. Moreover, in the GSE5851 dataset higher AXL RNA levels correlated with worse PFS with cetuximab in KRAS-exon2 WT chemorefractory patients.
AXL is a marker of poor prognosis in mCRC with consistent clinical and preclinical evidences of involvement in primary and acquired resistance to anti-EGFR drugs in RAS WT patients.
•AXL, marker of epithelial to mesenchymal transition, is expressed in metastatic colorectal cancer (mCRC).•AXL is associated with poor prognosis and shorter progression-free survival in patients with RAS wild-type (WT) mCRC.•AXL is a biomarker of both primary and acquired resistance to anti-epidermal growth factor receptor therapies in RAS WT mCRC.