Data from Nuclear Factor-κB p65/relA Silencing Induces Apoptosis and Increases Gemcitabine Effectiveness in a Subset of Pancreatic Cancer Cells

Abstract

<div>Abstract<p><b>Purpose:</b> Nuclear factor κB (NFκB) activity may increase survival and protect cancer cells from chemotherapy. Therefore, NFκB activity may be prognostic, and inhibition of NFκB may be useful for pancreatic cancer therapy. To test these hypotheses, we examined NFκB activity and the effects of inhibiting NFκB in several pancreatic cancer cell lines with differing sensitivities to gemcitabine.</p><p><b>Experimental Design:</b> The gemcitabine sensitivity of pancreatic cancer cell lines BxPC-3, L3.6pl, CFPAC-1, MPanc-96, PANC-1, and MIA PaCa-2 were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and fluorescence-activated cell sorting assays. NFκB levels were determined by electrophoretic mobility shift assay and reporter assays. The effects of gemcitabine on NFκB activity were determined <i>in vitro</i> and <i>in vivo</i>. NFκB was inhibited by silencing of the p65/relA subunit using small interfering RNA <i>in vitro</i> and by neutral liposomal delivery of small interfering RNA <i>in vivo,</i> and the effects were evaluated on gemcitabine sensitivity.</p><p><b>Results:</b> The cell lines L3.6pl, BxPC-3, and CFPAC-1 were sensitive, whereas MPanc-96, PANC-1, and MIA PaCa-2 were resistant to gemcitabine. No significant correlation was observed between basal NFκB activity and gemcitabine sensitivity. Gemcitabine treatment did not activate NFκB either <i>in vitro</i> or <i>in vivo</i>. Silencing of p65/relA induced apoptosis and increased gemcitabine killing of all gemcitabine-sensitive pancreatic cancer cells. No significant effects, however, were observed on gemcitabine-resistant pancreatic cancer cell lines either <i>in vitro</i> or <i>in vivo</i>.</p><p><b>Conclusions:</b> NFκB activity did not correlate with sensitivity to gemcitabine. Silencing of p65/relA was effective alone and in combination with gemcitabine in gemcitabine-sensitive but not gemcitabine-resistant pancreatic cancer cells. Thus, NFκB may be a useful therapeutic target for a subset of pancreatic cancers.</p></div>