Introduction: Fluorescence-guided surgery could potentially reduce local recurrence after pancreatic cancer resection. However, the ideal contrast agent for this purpose is not yet determined. The monoclonal antibody cetuximab targets the EGFR receptor, which is overexpressed in 64% of pancreatic cancers. We investigated the efficacy of near-infrared emitting silver sulphide Quantum Dot (QD)-cetuximab nanoconjugates for targeting EGFR-positive pancreatic cancer. Methods: 2-Mercaptopropionic acid-coated QDs were prepared from AgNO3 and Na2S. Pancreatic cancer cell lines PANC-1 and CFPAC-1 were confirmed EGFR-positive using a commercial AlexaFluor488-cetuximab probe. Nonconjugated QD and cetuximab-conjugated QD (QD-cetuximab) toxicity was assessed after 24 and 48 hours using MTT assay. Fluorescence microscopy was performed following a) formaldehyde-fixed immunofluorescence and b) live staining with QD-cetuximab for four hours at concentrations corresponding to 0, 10, 50, 100, 200, 400 and 600μg ml-1 of silver. Results: Untargeted QDs were non-toxic in both cell lines after 48 hours at all investigated concentrations, whereas QDcetuximab was toxic at 100µg ml-1 after 24 hours in PANC-1 and at 10µg ml-1 in CFPAC-1. Fixed immunofluorescence demonstrated EGFR targeting by QD-cetuximab at concentrations of 50μg ml-1 upwards in both cell lines. Live staining demonstrated similar efficacy of EGFR targeting up to 50μg ml-1 , although a reduction of fluorescence at higher concentrations was observed when compared to fixed immunofluorescence. Conclusion: Silver sulphide QD-cetuximab nanoconjugates have the potential to target live EGFR-positive pancreatic cancer cells at doses of up to 50 μg ml-1 . The reduction in QD fluorescence observed at higher concentrations is likely to be secondary to cetuximab toxicity.
Introduction: Pancreatic cancer often recurs following surgery suggesting new operative approaches are required. Fluorescence-guided surgery aims to assist surgeons in identifying tumour intraoperatively to facilitate complete resection. However, the ideal contrast agent for this purpose is not yet determined. The Rose criterion states that accurate imageguided surgery requires a Tumour-to-Background Ratio of contrast agent greater than 5. We investigated the potential of 5-aminolevulinic acid (ALA) for this purpose. Methods: Pancreatic cancer cell lines CFPAC-1 and PANC-1 were compared with the control pancreatic ductal cell line H6c7. Cells were seeded on day 1 and fluorescence measured on day 4 following 4, 8, 24 or 48 hours incubation with 0.25, 0.50, 0.75 or 1.00mM ALA. Fluorescence was measured using a plate reader and microscopy. Results: The maximum ALA-induced fluorescence for CFPAC-1 and PANC-1 was achieved after 48 hours incubation with 0.50mM ALA. Compared to cells incubated without ALA, a relative fluorescence increase of 39.4-fold in CFPAC-1 and 2.7-fold in PANC-1 was seen. ALA concentrations above 0.50mM did not result in higher fluorescence. In contrast, the control cell line H6c7 showed progressively increasing fluorescence with increasing ALA concentrations. The highest cancer/control cell fluorescence ratios for ALA were after 48 hours incubation with 0.25mM ALA; 122.9 in CFPAC-1 and 9.7 in PANC-1. Conclusion: ALA-induced fluorescence in CFPAC-1 is significantly higher than the control cell line H6c7. PANC-1 achieved only mildly increased fluorescence compared to H6c7. ALA has the potential to provide an adequate level of fluorescence for image-guided pancreatic surgery in ALA-susceptible cancers.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.