Multi-Target Inhibition of Cancer Cell Growth by SiRNA Cocktails and 5-Fluorouracil Using Effective Piperidine-Terminated Phosphorus Dendrimers

Abstract

Currently, RNAi based approaches for cancer treatment involving short double stranded RNA molecules (siRNA) are under vigorous scrutinization. Due to numerous biological obstacles, siRNA delivery into target cells requires protective escort. On the other hand, combining of siRNA-mediated gene silencing and action of conventional chemotherapeutics can propose additional enhancement of anticancer activity. In the present study, we investigated a siRNA cocktail able to downregulate anti-apoptotic genes (BCL-xL, BCL-2, MCL-1) and the chemotherapeutic agent 5-fluorouracil (5-FU) to evaluate multi-target cytotoxic effect on human cervical carcinoma cells (HeLa cell line). Novel phosphorus containing dendrimers of 3rd and 4th generations (namely AE2G3 and AE2G4) with voluminous piperidine terminal cationic groups were designed and tested as siRNA carriers. Dendrimers of both generations showed remarkable ability to bind pro-apoptotic siRNAs and provided 80-100% siRNA uptake by HeLa cells in the serum containing medium, while the widespread transfection agent Lipofectamine showed only~40% uptake. SiRNA cocktail (in low concentrations 50 and 100 nM) delivered by AE2G3 dendrimer caused almost complete elimination of cancer cells. We have discovered considerable increase of 5-FU cytotoxic effect by addition of AE2G3/siRNA cocktail complexes in low doses. Thus, we demonstrated the effectiveness of combined multi-target siRNA anticancer approach and described new highly effective serum stable nanomaterial vehicle for gene-based drugs.

Complexes of Pro-Apoptotic siRNAs and Carbosilane Dendrimers: Formation and Effect on Cancer Cells

“…The sequences of the oligoribonucleotides used are given in Table S1. The activity of these siRNAs and their cocktails (equimolar siRNA mixtures) against cancer cells upon dendrimer-mediated delivery has been demonstrated in other works [15,32].…”

Hydrogels of Polycationic Acetohydrazone-Modified Phosphorus Dendrimers for Biomedical Applications: Gelation Studies and Nucleic Acid Loading

“…Among the wide variety of dendrimer architectures, phosphorus dendrimers represent a unique object for nanomedicine [ 12 ]. They possess biological activity per se (such as anti-cancer [ 13 , 14 ], immunostimulatory [ 15 ] and anti-prion [ 16 ] as well as act as efficient carriers for plasmids [ 17 ] or therapeutic nucleic acids [ 18 , 19 , 20 , 21 ]. The ability of phosphorus dendrimers to be both structural block and functional element of a therapeutic construction can be fully realized in the design of dendrimer-based hydrogels.…”

Immunoreactivity changes of human serum albumin and alpha-1-microglobulin induced by their interaction with dendrimers

“…The protonated amino-terminated dendrimers (which were characterized in details in ref. [15]) ( Fig. 1) were obtained by firstly grafting of 1-(2-aminoethyl)-piperidine onto the periphery of precursor P(S)Cl2-terminated phosphorous dendrimers of third (G3, AE2G3 H+) and fourth (G4, AE2G4 H+) generation in the presence of N,N-diisopropylethylamine, and then protonation reaction with HCl.…”

“…Generation 4 (G4) of cationic PAMAM dendrimers proved to be the most significant carrier for DNA and RNA [8,9,13,14]. Previously we synthesized new cationic piperidine-based phosphorous dendrimers [15], which had excellent binding ability and could transfect siRNAs, providing 80-100% siRNA uptake by HeLa cells in serum-containing medium, whereas the widespread transfection agent, Lipofectamine, showed only˜40% uptake, with cationic PAMAM dendrimers of 3-4 generations giving only˜60-80% uptake (data not presented) [15]. Thus, the newly synthesized cationic AE2G3 and AE2G4 phosphorous dendrimers can be applied in RNAi-based tools for treatment of cancer and as efficient vehicles for gene-based drugs in transfection studies.…”