Dual inhibition of TGFβ and AXL as a novel therapy for human colorectal adenocarcinoma with mesenchymal phenotype

A subset of colorectal cancer (CRC) with a mesenchymal phenotype (CMS4) displays an aggressive disease, with an increased risk of recurrence after surgery, reduced survival, and resistance to standard treatments. It has been shown that the AXL and TGFβ signaling pathways are involved in epithelial-to-mesenchymal transition, migration, metastatic spread, and unresponsiveness to targeted therapies. However, the prognostic role of the combination of these biomarkers and the anti-tumor effect of AXL and TGFβ inhibition in CRC still has to be assessed. To evaluate the role of AXL and TGFβ as negative biomarker in CRC, we conducted an in-depth in silico analysis of CRC samples derived from the Gene Expression Omnibus. We found that AXL and TGFβ receptors are upregulated in CMS4 tumors and are correlated with an increased risk of recurrence after surgery in stage II/III CRC and a reduced overall survival. Moreover, we showed that AXL receptor is differently expressed in human CRC cell lines. Dual treatment with the TGFβ galunisertib and the AXL inhibitor, bemcentinib, significantly reduced colony formation and migration capabilities of tumor cells and displayed a strong anti-tumor activity in 3D spheroid cultures derived from patients with advanced CRC. Our work shows that AXL and TGFβ receptors identify a subgroup of CRC with a mesenchymal phenotype and correlate with poor prognosis. Dual inhibition of AXL and TGFβ could represent a novel therapeutic strategy for patients with this aggressive disease

Loss of MAPK-activated protein kinase 2 enables potent dendritic cell-driven anti-tumour T cell response

Abstract Maintaining dendritic cells (DC) in a state of dysfunction represents a key mechanism by which tumour cells evade recognition and elimination by the immune system. Limited knowledge about the intracellular mediators of DC dysfunction restricts success of therapies aimed at reactivating a DC-driven anti-tumour immune response. Using a cell type-specific murine knock-out model, we have identified MAPK-activated protein kinase 2 (MK2) as a major guardian of a suppressive DC phenotype in the melanoma tumour microenvironment. MK2 deletion in CD11c+ cells led to an expansion of stimulatory CD103+ DCs, mounting a potent CD8+ T cell response that resulted in elimination of highly aggressive B16-F10 tumours upon toll-like receptor (TLR) activation in the presence of tumour antigen. Moreover, tumour infiltration by suppressive myeloid cells was strongly diminished. These insights into the regulation of DC functionality reveal MK2 as a targetable pathway for DC-centred immunomodulatory cancer therapies

Journal of Cellular and Molecular Medicine / Gliomasphere marker combinatorics: multidimensional flow cytometry detects CD 44+/CD 133+/ITGA 6+/CD 36+ signature

Glioblastoma is the most dangerous brain cancer. One reason for glioblastoma's aggressiveness are glioblastoma stemlike cells. To target them, a number of markers have been proposed (CD 133, CD 44, CD 15, A2B5, CD 36, CXCR 4, IL 6R, L1CAM , and ITGA 6). A comprehensive study of coexpression patterns of them has, however, not been performed so far. Here, we mapped the multidimensional coexpression profile of these stemnessassociated molecules. Gliomaspheres an established model of glioblastoma stemlike cells were used. Seven different gliomasphere systems were subjected to multicolor flow cytometry measuring the nine markers CD 133, CD 44, CD 15, A2B5, CD 36, CXCR 4, IL 6R, L1CAM , and ITGA 6 all simultaneously based on a novel 9marker multicolor panel developed for this study. The viSNE dimensionality reduction algorithm was applied for analysis. All gliomaspheres were found to express at least five different glioblastoma stemlike cell markers. Multidimensional analysis showed that all studied gliomaspheres consistently harbored a cell population positive for the molecular signature CD 44+/CD 133+/ITGA 6+/CD 36+. Glioblastoma patients with an enrichment of this combination had a significantly worse survival outcome when analyzing the two largest available The Cancer Genome Atlas datasets (MIT /Harvard Affymetrix: P = 0.0015, University of North Carolina Agilent: P = 0.0322). In sum, we detected a previously unknown marker combination demonstrating feasibility, usefulness, and importance of highdimensional gliomasphere marker combinatorics.(VLID)510252

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

Background: 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. Methods: 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. Results: 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. Conclusions: 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