46 Wortmannin chemical structure versus 0.68, p = 0.03) in comparison to scramble siRNA control (Figure 3). Treatment with LPA had no significant effect on OAC cell proliferation. NET1 knockdown cells treated with LPA showed significantly reduced proliferation (39% reduction, p = 0.01) compared to control cells treated with
LPA under the same conditions. Figure 3 OE33 cell proliferation measured after NET1 knockdown (KD) and 5 μM LPA stimulation compared with control (scramble siRNA) cells. Statistically significant differences are shown in bold. NET1 Mediates LPA induced migration in OAC cells Figure 4 illustrates the effects of LPA treatment and NET1 knockdown on OAC cell migration, using gap width at time 0 as a reference. A higher level of migration was observed in LPA treated cells compared to non-targeting
(NT) siRNA (control) cells (383.3 mean pixels versus BV-6 in vitro 318.1 or 20% increase in migration, p = 0.01). NET1 gene knockdown (KD) resulted in 25% reduction in migration (240 mean pixels versus 318.1, p = 0.03). NET1 knockdown cells treated with LPA had a 22% reduction in migration in comparison with control (NT + LPA), (298.5 versus 383.3 mean pixels, p = 0.0003). Figure 4 Trans-well migration of OE33 cells after NET1 gene knockdown (KD), 5μM LPA stimulation (NT+LPA) and both conditions combined (KD+LPA). A) Migration across a gap is graphed by average number of pixels. Non-targeting siRNA (NT control) treated cells acted as a sham control for gene knockdown and time=0 is included as a reference. Selleck SRT2104 Statistically significant differences are shown in bold. B) Light microcopy images (10× magnification) of trans-well migration
assay. NET1 Promotes trans-membrane invasion in OAC cells NET1 knockdown cells were 45% less invasive at 24 hours than control cells, as shown in Figure 5 (56.8 versus 102.6 mean cells per high power field, p = 0.04). Invasion was increased Niclosamide by 78% in control cells after 5 μM LPA stimulation compared with NET1 knockdown cells (117.1 vs 66.1 mean cells per high power field, p = 0.01). Figure 5 Trans-membrane invasion of OE33 cells after NET1 knockdown (KD) and 5 μM LPA stimulation (control + LPA) over 24 hours compared with control (NT/scramble siRNA). The final column represents both conditions combined (KD + LPA). Statistically significant differences are shown in bold. Discussion The biological events in OAC carcinogenesis and metastasis are poorly understood. NET1 has been shown to be functionally important as a mediator of invasion and metastasis in gastric adenocarcinoma [12, 16] and is prognostically significant in other epithelial cancers [18, 20]. We have demonstrated very high levels of NET1 expression in OAC and this strengthens our central hypothesis that this well characterised oncoprotein may be an important player in the molecular events leading to neoplastic progression in Barrett’s and OAC.