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Title: Identifying compounds that inhibit S100P-RAGE binding as a novel therapy for pancreatic cancer
Author: Ogbeni, Deborah
ISNI:       0000 0004 7961 6050
Awarding Body: University of Hertfordshire
Current Institution: University of Hertfordshire
Date of Award: 2019
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High levels of S100 calcium-binding protein P (S100P) have been found in pancreatic ductal adenocarcinoma (PDAC), and several other types of aggressive cancers. The overexpression of S100P in different types of cancer has been related to drug resistance, metastasis, and poor clinical outcome. Multiple studies have confirmed that S100P expression enhances cell survival, proliferation, and invasion through interactions with intracellular targets and extracellular interaction with the receptor for advanced glycation end products (RAGE). Moreover, previous in vivo studies in mouse models of pancreatic cancer have shown that inhibition or silencing of S100P reduces tumour growth and metastasis, and enhances response to gemcitabine therapy. As such, S100P has emerged as a promising biological target for novel anticancer drug design. Computational modelling of a small-molecule binding site in S100P was used in a virtual screen to identify hit compounds, predicted to bind S100P and inhibit its tumour-promoting effects. In this body of research an optimised enzyme-linked immunosorbent assay (ELISA), to rapidly identify S100P-inhibiting compounds, was further optimised to improve sensitivity based on a published protocol; hit compounds were then screened for inhibition of S100P-RAGE interaction. Ninety-three compounds, at concentrations ranging from 1 nM-1 μM, were screened in triplicate. Twenty-one of these compounds were statistically significant at inhibiting S100P-RAGE (P < 0.001) with greater potency than cromolyn, an anti-allergic drug known to bind S100P both in vitro and in vivo. The 21 compounds from this assay were then tested for their effects on two human pancreatic cancer cell lines; S100P-overexpressing cells (BxPC-3) and cells not expressing S100P (Panc-1) using MTS (metabolic activity), and LDH release (cell toxicity) assays and the Transwell cell invasion assay (metastasis/invasion characteristics). The chick chorioallantoic membrane assay and western blot analysis were also performed to assess the effects of treatment with hit compounds on blood vessel formation and cell signalling pathways, respectively. The MTS and LDH release assays revealed that the 13 compounds tested neither had an inhibitory effect on cell proliferation nor exhibit general cytotoxicity over an extended period of 8 days. BxPC-3 cells treated with 13 of the hit compounds for 48 h, at 10 µM, demonstrated a significant reduction (P < 0.001) in cell invasion; whereas no effect was observed for the Panc-1 cells; suggesting an S100P-specific mechanism. The CAM assay showed 7 of the 13 compounds significantly (P<0.001) inhibited angiogenesis in fertilised chick embryos at 10 µM and 100 µM. Although the western blot analysis failed to identify the exact mechanism(s) involved, the data obtained suggest that the measurement of S100P-RAGE binding by ELISA can be used as a screen to identify compounds that have functional effects in S100P-expressing pancreatic cancer cells and enable further development of a potential therapy for pancreatic cancer.
Supervisor: MacKenzie, Louise ; Rossiter, Sharon ; Chau, David ; Patel, Pryank Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available