To date, pancreatic ductal adenocarcinoma (PDAC) carries a poor prognosis, which is related to both tumor biology and advanced stage at the moment of detection. Avoiding delayed diagnosis is therefore crucial, but the absence of sensitive and specific biomarkers makes the early diagnosis challenging. In this regard, recent advances in nanotechnology have provided promising outcomes that could pave the way to future developments of early diagnostic tools. They are based on the study of the interactions among nanoparticles (NPs) and blood plasma biomolecules. Indeed, upon incubation with human plasma, NPs act as 'concentrators' of molecules, which adsorb on their surface and form an outer biomolecular layer, or biomolecular corona (BC). Features and composition of the BC depend on NP's physical-chemical properties (size, shape, surface chemistry), environmental factors (temperature, PH) and molecular source, i.e. the biological medium within which the NP is embedded. Hence, the detection of specific corona molecules, which are related to pathological conditions, could represent an effective way to exploit NP-blood interactions for diagnostic purposes. The main aim of this project is the development of a BC-based blood test for early cancer detection, by exploiting some peculiar properties of graphene oxide (GO) nanoparticles. The use of GO-BC in diagnostics is extremely promising since (i) GO can selectively adsorb plasma proteins which are poorly concentrated; (ii) protein patterns adsorbed can be varied by modulating size and surface oxidation and (iii) GO-BC is sensitive for early cancer detection. In this project, we will explore these properties to burst pancreatic cancer test sensitivity in the detection of minor protein changes at the very early stages of disease. We predict that a systematic investigation of GO-BC may improve our knowledge of PDAC biology and that the BC technology may offer new opportunities for PDAC detection and biomarkers identification.
To date, there are no economic and minimally invasive tools allowing large-scale screening of pancreatic ductal adenocarcinoma (PDAC), but a non-biopsy-based test detecting serum carbohydrate antigen 19-9 (CA19-9) is routinely used. However, this approach fails to be specific and is poorly sensitive. Therefore, it becomes a priority to develop more specific and sensitive diagnostic tests. In this field, conjugating basic research (proteomic, metabolomics markers, microRNAs, genetic markers, circulating tumor cells and epigenetic markers) and clinical, is promising [1], but still too expensive and time-consuming. On the other side, the emerging biomolecular corona (BC) technology depends on non-invasive and cheap tools. The molecular composition of the BC formed around NPs could change in cancer and non-cancer patients' blood and it has been shown that gel electrophoresis can reveal such differences [2]. However, the above-mentioned alterations are often small, difficult to be detected and make the search continues for new biomarkers challenging. Thus, choose of the NP formulation, standardization of the experimental protocols and the employment of proper, cheap and user-friendly experimental devices may really make the difference in this field.
We will use graphene oxide (GO) NPs, as 'nanoconentrators' of blood plasma proteins. Despite an intense research activity on graphene-based nanomaterials, the corresponding perspectives of application in cancer diagnosis and screening are poorly explored. However, due to its peculiar chemical-physical properties, GO is particularly suitable for the development of NP-based blood tests. Indeed, the exposure of GO to plasma of patients with cancer significantly affects the composition of GO-BC complexes. Furthermore, with respect to other materials, GO has the lowest affinity to albumin [3]. Albumin is the most abundant protein in blood and is often found in the BC of many nanomaterials. It gives rises to a high intensity band at 60 kDa on electrophoretic gels thus lowering the resolution of the SDS-PAGE analysis. This adsorption limits the adsorption of other proteins, which are typically present at low concentration in human plasma and could be hallmark of cancerogenesis. Among these proteins, there are many PDAC markers such as Apolipoprotein A-IV and Alpha-1-antichymotrypsin. This protein selection by GO has been ascribed to the low surface curvature, combined to the presence of its negatively charged functional groups, resulting in both hydrogen binding and electrostatic interactions, in addition to hydrophobic and van der Waals interactions [3]. Finally, GO interaction with plasma proteins such as albumin, fibrinogen and globulin can be modulated by GO lateral size [4] and surface chemistry. We aim to exploit the extraordinary adsorption ability of GO NPs to improve resolution and accuracy of the protein patterns associated to PDAC and NOP coronas. This may lead to the groundbreaking ability of detecting changes in the BC even when the total quantity of single protein biomarkers is about the same for cancer and healthy patients. As a result, we predict that this approach could improve the sensitivity and specificity of NP-based blood test for early cancer diagnosis and could help identify different cancer stages by a simple, non-invasive tool.
1. Y. Ma et al., Annals of Translational Medicine 2016, 4 (23).
2. D. Caputo et al., Nanoscale 9(1) (2017)
3. M. Sopotnik et al., Carbon 95 (2015
4. K.P. Loh, et al., Nanoscale 8(17) (2016)