Inhibition of angiogenesis- and inflammation-inducing factors in human colon cancer cells in vitro and in ovo by free and nanoparticle-encapsulated redox dye, DCPIP

<p>Abstract</p> <p>Background</p> <p>The redox dye, DCPIP, has recently shown to exhibit anti-melanoma activity <it>in vitro </it>and <it>in vivo</it>. On the other hand, there is increasing evidence that synthetic nanoparticles can serve as highly efficient carriers of drugs and vaccines for treatment of various diseases. These nanoparticles have shown to serve as potent tools that can increase the bioavailability of the drug/vaccine by facilitating absorption or conferring sustained and improved release. Here, we describe results on the effects of free- and nanoparticle-enclosed DCPIP as anti-angiogenesis and anti-inflammation agents in a human colon cancer HCT116 cell line <it>in vitro</it>, and in induced angiogenesis <it>in ovo</it>.</p> <p>Results</p> <p>The studies described in this report indicate that (a) DCPIP inhibits proliferation of HCT116 cells <it>in vitro</it>; (b) DCPIP can selectively downregulate expression of the pro-angiogenesis growth factor, VEGF; (c) DCPIP inhibits activation of the transcriptional nuclear factor, NF-κB; (d) DCPIP can attenuate or completely inhibit VEGF-induced angiogenesis in the chick chorioallantoic membrane; (e) DCPIP at concentrations higher than 6 μg/ml induces apoptosis in HCT116 cells as confirmed by detection of caspase-3 and PARP degradation; and (f) DCPIP encapsulated in nanoparticles is equally or more effective than free DCPIP in exhibiting the aforementioned properties (a-e) in addition to reducing the expression of COX-2, and pro-inflammatory proteins IL-6 and IL-8.</p> <p>Conclusions</p> <p>We propose that, DCPIP may serve as a potent tool to prevent or disrupt the processes of cell proliferation, tissue angiogenesis and inflammation by directly or indirectly targeting expression of specific cellular factors. We also propose that the activities of DCPIP may be long-lasting and/or enhanced if it is delivered enclosed in specific nanoparticles.</p

Nanoparticle-based delivery of siDCAMKL-1 increases microRNA-144 and inhibits colorectal cancer tumor growth via a Notch-1 dependent mechanism

<p>Abstract</p> <p>Background</p> <p>The development of effective drug delivery systems capable of transporting small interfering RNA (siRNA) has been elusive. We have previously reported that colorectal cancer tumor xenograft growth was arrested following treatment with liposomal preparation of siDCAMKL-1. In this report, we have utilized Nanoparticle (NP) technology to deliver DCAMKL-1 specific siRNA to knockdown potential key cancer regulators. In this study, mRNA/miRNA were analyzed using real-time RT-PCR and protein by western blot/immunohistochemistry. siDCAMKL-1 was encapsulated in Poly(lactide-<it>co</it>-glycolide)-based NPs (NP-siDCAMKL-1); Tumor xenografts were generated in nude mice, treated with NP-siDCAMKL-1 and DAPT (γ-secretase inhibitor) alone and in combination. To measure <it>let-7a </it>and <it>miR-144 </it>expression <it>in vitro</it>, HCT116 cells were transfected with plasmids encoding the firefly luciferase gene with <it>let-7a </it>and <it>miR-144 </it>miRNA binding sites in the 3'UTR.</p> <p>Results</p> <p>Administration of NP-siDCAMKL-1 into HCT116 xenografts resulted in tumor growth arrest, downregulation of proto-oncogene c-Myc and Notch-1 via <it>let-7a </it>and <it>miR-144 </it>miRNA-dependent mechanisms, respectively. A corresponding reduction in <it>let-7a </it>and <it>miR-144 </it>specific luciferase activity was observed <it>in vitro</it>. Moreover, an upregulation of EMT inhibitor <it>miR-200a </it>and downregulation of the EMT-associated transcription factors ZEB1, ZEB2, Snail and Slug were observed <it>in vivo</it>. Lastly, DAPT-mediated inhibition of Notch-1 resulted in HCT116 tumor growth arrest and down regulation of Notch-1 via a <it>miR-144 </it>dependent mechanism.</p> <p>Conclusions</p> <p>These findings demonstrate that nanoparticle-based delivery of siRNAs directed at critical targets such as DCAMKL-1 may provide a novel approach to treat cancer through the regulation of endogenous miRNAs.</p