Expression Analysis of α5 Integrin Subunit Reveals Its Upregulation as a Negative Prognostic Biomarker for Glioblastoma

Bioimaging Nucleic-Acid Aptamers with Different Specificities in Human Glioblastoma Tissues Highlights Tumoral Heterogeneity

Nucleic-acid aptamers are of strong interest for diagnosis and therapy. Compared with antibodies, they are smaller, stable upon variations in temperature, easy to modify, and have higher tissue-penetration abilities. However, they have been little described as detection probes in histology studies of human tissue sections. In this study, we performed fluorescence imaging with two aptamers targeting cell-surface receptors EGFR and integrin α5β1, both involved in the aggressiveness of glioblastoma. The aptamers’ cell-binding specificities were confirmed using confocal imaging. The affinities of aptamers for glioblastoma cells expressing these receptors were in the 100–300 nM range. The two aptamers were then used to detect EGFR and integrin α5β1 in human glioblastoma tissues and compared with antibody labeling. Our aptafluorescence assays proved to be able to very easily reveal, in a one-step process, not only inter-tumoral glioblastoma heterogeneity (differences observed at the population level) but also intra-tumoral heterogeneity (differences among cells within individual tumors) when aptamers with different specificities were used simultaneously in multiplexing labeling experiments. The discussion also addresses the strengths and limitations of nucleic-acid aptamers for biomarker detection in histology.

Temozolomide-Acquired Resistance Is Associated with Modulation of the Integrin Repertoire in Glioblastoma, Impact of α5β1 Integrin

Despite extensive treatment, glioblastoma inevitably recurs, leading to an overall survival of around 16 months. Understanding why and how tumours resist to radio/chemotherapies is crucial to overcome this unmet oncological challenge. Primary and acquired resistance to Temozolomide (TMZ), the standard-of-care chemotherapeutic drug, have been the subjects of several studies. This work aimed to evaluate molecular and phenotypic changes occurring during and after TMZ treatment in a glioblastoma cell model, the U87MG. These initially TMZ-sensitive cells acquire long-lasting resistance even after removal of the drug. Transcriptomic analysis revealed that profound changes occurred between parental and resistant cells, particularly at the level of the integrin repertoire. Focusing on α5β1 integrin, which we proposed earlier as a glioblastoma therapeutic target, we demonstrated that its expression was decreased in the presence of TMZ but restored after removal of the drug. In this glioblastoma model of recurrence, α5β1 integrin plays an important role in the proliferation and migration of tumoral cells. We also demonstrated that reactivating p53 by MDM2 inhibitors concomitantly with the inhibition of this integrin in recurrent cells may overcome the TMZ resistance. Our results may explain some integrin-based targeted therapy failure as integrin expressions are highly switchable during the time of treatment. We also propose an alternative way to alter the viability of recurrent glioblastoma cells expressing a high level of α5β1 integrin.

ITGA5 is an independent prognostic biomarker and potential therapeutic target for laryngeal squamous cell carcinoma

Background

Integrin α5 (ITGA5) was involved in a variety of cancers. However, the role of ITGA5 in laryngeal squamous cell carcinoma (LSCC) remains unknown.

Methods

The expression of ITGA5 and the corresponding clinicopathological parameters of LSCC patients the TCGA database. Five datasets (GSE51985, GSE59102, GSE84957, GSE27020, and GSE65858) were downloaded from the GEO database as validation sets. Kaplan–Meier plotter, Cox regression analysis, and nomogram were performed to determine the prognostic value of ITGA5 in LSCC. GO, KEGG, and GSEA were used to explore the underlying biological functions of ITGA5 in LSCC. The algorithms ESTIMATE and CIBERSORT were adopted to evaluate the association between ITGA5 and the infiltration of the immune cells. The algorithm pRRophetic was used to estimate the response to chemotherapeutic drugs.

Results

The expression of ITGA5 was higher in the LSCC samples and linked to poor overall survival and recurrence‐free survival. Further, the Cox regression analysis confirmed that high expression of ITGA5 was an independent unfavorable prognostic factor. The predictive performance of nomogram based on the expression of ITGA5 was accurate and practical. The functional enrichment analysis confirmed that ITGA5 was related to the construction of the components and structures of the extracellular matrix. Finally, patients with high ITGA5 expression were more likely to benefit from docetaxel and gemcitabine.

Conclusion

The expression of ITGA5 was elevated in the LSCC and was a predictor for prognosis and chemotherapeutic response in LSCC patients.