Tumour angiogenesis, the formation of new blood vessels within a tumour, is a hallmark of cancers, that allows them to grow beyond a critical size and to metastasize to other organs. As the key driver of tumour angiogenesis, αvβ3 integrin is both an established therapeutic target for anti-angiogenic drugs and a biomarker for imaging agents. Accurate detection of αvβ3 integrin in angiogenic tumours impacts patient prognosis and could report on therapy response. Over the last twenty years, novel αvβ3 integrin-targeted radiotracers have been developed for PET imaging of tumour angiogenesis. While most radiotracers have shown their utility as diagnostic tools, only a few focussed on evaluating response to treatment, partly due to complex biology of the integrin receptors. The aim of this project was the in-vitro biological testing of a novel αvβ3-targeted radiotracer, [3H]ZMPZAT71, and the corresponding unlabelled compound for targeted delivery of a cytotoxic drug, paclitaxel (PTX). Firstly, this piece of work involved validation of this radiotracer to assess expression of αvβ3 integrin. Secondly, [3H]ZMPZAT71 was investigated as a biomarker for assessing response to pharmacological inhibitors of cell signalling pathways. Thirdly, the targeting moiety (ZMPZAT71) conjugated with paclitaxel was studied for integrinmediated drug delivery. The results presented herein demonstrate that radiotracer binding to αvβ3 integrin is dependent not only on the expression levels, but also on the activation status of αvβ3 integrin. Furthermore, this piece of information was used to explain radiotracer binding in response to various pharmacological inhibitors of key cell signalling pathways. Additionally, the integrin-targeted chemotherapeutic exhibited selective cytotoxic effect, explained by enhanced apoptosis of cancer cells compared to PTX alone, together with anti-migratory and anti-invasive effects from the targeting moiety. This study provides valuable information about the molecular mechanisms regulated by αvβ3 integrin, supporting the development of integrin-targeted therapeutics and imaging.