Vascularization is fundamental to the growth and spread of tumor cells to distant sites. As a consequence, angiogenesis, the sprouting of new blood vessels from existing ones, is a characteristic trait of cancer. In 1971, Judah Folkman postulated that tumour growth is angiogenesis dependent and that by cutting off blood supply, a neoplastic lesion could be potentially starved into remission. Decades of research have been devoted to understanding the role that vascular endothelial growth factor (VEGF) plays in tumor angiogenesis, and it has been identified as a significant pro-angiogenic factor that is frequently overexpressed within a tumor mass. Today, anti-VEGF drugs such as Sunitinib, Sorafenib, Axitinib, Tanibirumab, and Ramucirumab have been approved for the treatment of advanced and metastatic cancers. However, anti-angiogenic therapy has turned out to be more complex than originally thought. The failure of this therapeutic option calls for a reevaluation of VEGF as the major target in anti-angiogenic cancer therapy. The call for reassessment is based on two rationales: first, tumour blood vessels are abnormal, disorganized, and leaky; this not only prevents optimal drug delivery but it also promotes hypoxia and metastasis; secondly, tumour growth or regrowth might be blood vessel dependent and not angiogenesis dependent as tumour cells can acquire blood vessels via non-angiogenic mechanisms. Therefore, a critical assessment of VEGF, VEGFRs, and their inhibitors could glean newer options such as repurposing anti-VEGF drugs as vascular normalizing agents to enhance drug delivery of immune checkpoint inhibitors.

BACKGROUND: Hepatocellular carcinoma (HCC) is a highly vascularized tumor in which abnormal blood vessels contribute to poor treatment efficacy and prognosis. In this study, we assessed the efficacy, safety, and potential ability of bevacizumab to normalize tumor vascularity in patients with advanced HCC.
METHODS: Patients with histologically or clinically confirmed advanced HCC that were refractory to conventional transarterial chemoembolization (c-TACE) received a transarterial infusion of bevacizumab (5 mg/kg), followed by c-TACE (named as BEVA-TACE). The primary endpoint was overall survival (OS), which was defined as the time from a patient identified as TACE refractory to the occurrence of death. The secondary endpoints included progression-free survival (PFS) and the disease control rate (DCR).
RESULTS: From January 2014 to December 2017, 20 patients with Barcelona Clinic Liver Cancer (BCLC) staging scores C (80.0%) or D (20.0%) received BEVA-TACE. The median OS time was 9.2 months [95% confidence interval (CI): 2.1-22.6 months]. The median PFS time was 6.3 months (95% CI: 1.0-10.5 months). Despite the late stage, 1 patient (5.0%) had a complete response (CR), 6 patients (30.0%) had a partial response (PR), and 10 patients (50.0%) had stable disease (SD) [overall response rate (ORR) 30.0%; DCR 85.0%]. The most common adverse events (AEs) were postembolic syndrome (25%), hyperbilirubinemia (10.0%), and melena (10.0%). Severe III-IV oral mucositis and hypertension were observed in only 1 patient (5.0%) during the follow-up period.
CONCLUSIONS: BEVA-TACE showed clinical efficacy, and patients with TACE-refractory HCC had acceptable AE rates. A low dose of targeted localized vessel bevacizumab infusion may normalize the condition of tumor blood vessels in patients with advanced HCC.

Integrins have been extensively investigated as therapeutic targets over the last decades, which has been inspired by their multiple functions in cancer progression, metastasis, and angiogenesis as well as a continuously expanding number of other diseases, e.g., sepsis, fibrosis, and viral infections, possibly also Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). Although integrin-targeted (cancer) therapy trials did not meet the high expectations yet, integrins are still valid and promising targets due to their elevated expression and surface accessibility on diseased cells. Thus, for the future successful clinical translation of integrin-targeted compounds, revisited and innovative treatment strategies have to be explored based on accumulated knowledge of integrin biology. For this, refined approaches are demanded aiming at alternative and improved preclinical models, optimized selectivity and pharmacological properties of integrin ligands, as well as more sophisticated treatment protocols considering dose fine-tuning of compounds. Moreover, integrin ligands exert high accuracy in disease monitoring as diagnostic molecular imaging tools, enabling patient selection for individualized integrin-targeted therapy. The present review comprehensively analyzes the state-of-the-art knowledge on the roles of RGD-binding integrin subtypes in cancer and non-cancerous diseases and outlines the latest achievements in the design and development of synthetic ligands and their application in biomedical, translational, and molecular imaging approaches. Indeed, substantial progress has already been made, including advanced ligand designs, numerous elaborated pre-clinical and first-in-human studies, while the discovery of novel applications for integrin ligands remains to be explored.