Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy that often presents clinically at an advanced stage and that may be confused with chronic pancreatitis (CP). Conversely, CP may be misdiagnosed as PDAC leading to unwarranted pancreas resection. Therefore, early PDAC diagnosis and clear differentiation between PDAC and CP are crucial for improved care. Exosomes are circulating microvesicles whose components can serve as cancer biomarkers. We compared exosomal glypican-1 (GPC1) and microRNA levels in normal control subjects and in patients with PDAC and CP. We report that exosomal GPC1 is not diagnostic for PDAC, whereas high exosomal levels of microRNA-10b, (miR-10b), miR-21, miR-30c, and miR-181a and low miR-let7a readily differentiate PDAC from normal control and CP samples. By contrast with GPC1, elevated exosomal miR levels decreased to normal values within 24 h following PDAC resection. All 29 PDAC cases exhibited significantly elevated exosomal miR-10b and miR-30c levels, whereas 8 cases had normal or slightly increased CA 19-9 levels. Thus, our exosomal miR signature is superior to exosomal GPC1 or plasma CA 19-9 levels in establishing a diagnosis of PDAC and differentiating between PDAC and CP.

MicroRNAs are short noncoding RNAs consisting of 18–25 nucleotides that target specific mRNA moieties for translational repression or degradation, thereby modulating numerous biological processes. Although microRNAs have the ability to behave like oncogenes or tumor suppressors in a cell-autonomous manner, their exact roles following release into the circulation are only now being unraveled and it is important to establish sensitive assays to measure their levels in different compartments in the circulation. Here, an ultrasensitive localized surface plasmon resonance (LSPR)-based microRNA sensor with single nucleotide specificity was developed using chemically synthesized gold nanoprisms attached onto a solid substrate with unprecedented long-term stability and reversibility. The sensor was used to specifically detect microRNA-10b at the attomolar (10–18 M) concentration in pancreatic cancer cell lines, derived tissue culture media, human plasma, and media and plasma exosomes. In addition, for the first t...

Vascular endothelial growth factor (VEGF) is a potent angiogenic polypeptide that activates 2 distinct high‐affinity tyrosine kinase receptors, flk‐1/KDR and flt‐1. In the present study, we characterized the expression of VEGF and its receptors flk‐1/KDR and flt‐1 in the normal human pancreas and in human pancreatic cancer tissues and cell lines. VEGF, flk‐1/KDR and flt‐1 mRNA levels were elevated in cancer tissues compared with normal pancreas. By immuno‐histochemistry, VEGF, flk‐1/KDR and flt‐1 immunoreactivity co‐localized in many of the cancer cells within the tumor mass. Three (AsPC‐1, Capan‐1 and MIAPaCa‐2) of 6 pancreatic cancer cell lines expressed flk‐1/KDR mRNA and protein, and 4 cell lines (AsPC‐1, Capan‐1, T3M4 and PANC‐1) expressed flt‐1 mRNA transcripts. Binding studies with ¹²⁵I‐labeled VEGF165 indicated that only Capan‐1 cells exhibited high levels of specific binding. Furthermore, VEGF enhanced the growth of Capan‐1 cells but was without effect in the other cell lines. VEGF also enhanced mitogen‐activated protein kinase (MAPK) phosphorylation and c‐fos induction in Capan‐1 cells, whereas the MAPK kinase inhibitor PD98059 abolished the growth‐stimulatory effect of VEGF. These data indicate that human pancreatic cancers have the capacity to over‐express VEGF and its receptors and suggest that in some instances VEGF may directly promote pancreatic cancer growth via the MAPK pathway. Int. J. Cancer 85:27–34, 2000.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. Althoughthe specific mechanisms that dictate its biological aggressiveness are notclearly established, it is characterized by a variety of molecularalterations as well as by the overexpression of mitogenic and angiogenicgrowth factors and their receptors. PDACs also express high levels ofvascular endothelial growth factor (VEGF). Recent studies indicate thatsuppression of VEGF expression attenuates pancreatic cancer celltumorigenicity in a nude mouse model, and that VEGF can exert directmitogenic effects on some pancreatic cancer cells. These findings suggestthat cancer cell derived VEGF promotes pancreatic cancer growth in vivo viaa paracrine angiogenic pathway and an autocrine mitogenic pathway, andprovide novel opportunities for therapeutic intervention in this deadlydisease.

MicroRNAs (miRs) are small noncoding RNAs that regulate mRNA stability and/or translation. Because of their release into the circulation and their remarkable stability, miR levels in plasma and other biological fluids can serve as diagnostic and prognostic disease biomarkers. However, quantifying miRs in the circulation is challenging due to issues with sensitivity and specificity. This Letter describes for the first time the design and characterization of a regenerative, solid-state localized surface plasmon resonance (LSPR) sensor based on highly sensitive nanostructures (gold nanoprisms) that obviates the need for labels or amplification of the miRs. Our direct hybridization approach has enabled the detection of subfemtomolar concentration of miR-X (X = 21 and 10b) in human plasma in pancreatic cancer patients. Our LSPR-based measurements showed that the miR levels measured directly in patient plasma were at least 2-fold higher than following RNA extraction and quantification by reverse transcriptase-polymerase chain reaction. Through LSPR-based measurements we have shown nearly 4-fold higher concentrations of miR-10b than miR-21 in plasma of pancreatic cancer patients. We propose that our highly sensitive and selective detection approach for assaying miRs in plasma can be applied to many cancer types and disease states and should allow a rational approach for testing the utility of miRs as markers for early disease diagnosis and prognosis, which could allow for the design of effective individualized therapeutic approaches.