Integrin-alpha10 drives tumorigenesis in sarcoma

The effects of inhibition and siRNA knockdown of collagen-binding integrins on human umbilical vein endothelial cell migration and tube formation

Blood vessels in the body are lined with endothelial cells which have vital roles in numerous physiological and pathological processes. Collagens are major constituents of the extracellular matrix, and many adherent cells express several collagen-binding adhesion receptors. Here, we study the endothelium-collagen interactions mediated by the collagen-binding integrins, α1β1, α2β1, α10β1 and α11β1 expressed in human umbilical vein endothelial cells (HUVECs). Using qPCR, we found expression of the α10 transcript of the chondrocyte integrin, α10β1, along with the more abundant α2, and low-level expression of α1. The α11 transcript was not detected. Inhibition or siRNA knockdown of the α2-subunit resulted in impaired HUVEC adhesion, spreading and migration on collagen-coated surfaces, whereas inhibition or siRNA knockdown of α1 had no effect on these processes. In tube formation assays, inhibition of either α1 or α2 subunits impaired the network complexity, whereas siRNA knockdown of these integrins had no such effect. Knockdown of α10 had no effect on cell spreading, migration or tube formation in these conditions. Overall, our results indicate that the collagen-binding integrins, α1β1 and α2β1 play a central role in endothelial cell motility and self-organisation.

Identification of new candidate genes and signalling pathways associated with the development of neuroendocrine pancreatic tumours based on next generation sequencing data

Despite advances in classification, treatment, and imaging, neuroendocrine tumours remain a clinically complex subject. In this work, we studied the genetic profile of well-differentiated pancreatic neuroendocrine tumours (PanNETs) in a cohort of Caucasian patients and analysed the signalling pathways and candidate genes potentially associated with the development of this oncological disease. Twenty-four formalin-fixed paraffin-embedded (FFPE) samples of well-differentiated PanNETs were subjected to massive parallel sequencing using the targeted gene panel (409 genes) of the Illumina NextSeq 550 platform (San Diego, USA). In 24 patients, 119 variants were identified in 54 genes. The median mutation rate per patient was 5 (2.8-7). The detected genetic changes were dominated by missense mutations (67%) and nonsense mutations (29%). 18% of the mutations were activating, 35% of the variants led to a loss of function of the encoded protein, and 52% were not classified. Twenty-six variants were described as new. Functionally significant changes in the tertiary structure and activity of the protein molecules in an in silico assay were predicted for 5 new genetic variants. The 5 highest priority candidate genes were selected: CREB1, TCF12, PRKAR1A, BCL11A, and BUB1B. Genes carrying the identified mutations participate in signalling pathways known to be involved in PanNETs; in addition, 38% of the cases showed genetic changes in the regulation of the SMAD2/3 signalling pathway. Well-differentiated PanNETs in a Russian cohort demonstrate various molecular genetic features, including new genetic variations and potential driver genes. The highlighted molecular genetic changes in the SMAD2/3 signalling pathway suggest new prospects for targeted therapy.

Are Integrins Still Practicable Targets for Anti-Cancer Therapy?

Correlative clinical evidence and experimental observations indicate that integrin adhesion receptors, in particular those of the αV family, are relevant to cancer cell features, including proliferation, survival, migration, invasion, and metastasis. In addition, integrins promote events in the tumor microenvironment that are critical for tumor progression and metastasis, including tumor angiogenesis, matrix remodeling, and the recruitment of immune and inflammatory cells. In spite of compelling preclinical results demonstrating that the inhibition of integrin αVβ3/αVβ5 and α5β1 has therapeutic potential, clinical trials with integrin inhibitors targeting those integrins have repeatedly failed to demonstrate therapeutic benefits in cancer patients. Here, we review emerging integrin functions and their proposed contribution to tumor progression, discuss preclinical evidence of therapeutic significance, revisit clinical trial results, and consider alternative approaches for their therapeutic targeting in oncology, including targeting integrins in the other cells of the tumor microenvironment, e.g., cancer-associated fibroblasts and immune/inflammatory cells. We conclude that integrins remain a valid target for cancer therapy; however, agents with better pharmacological properties, alternative models for their preclinical evaluation, and innovative combination strategies for clinical testing (e.g., together with immuno-oncology agents) are needed.