ABSTRACT
Lipid-based nanoparticles [NLP] are PEGylated carriers composed of lipids and encapsulated nucleic acids with a diameter less than 100 nm. The presence of PEG in the NLP formulation improves the particle pharmacokinetic behavior. The purpose of this study was to prepare and characterize NLPs containing MDR1 siRNA and evaluate their cytotoxicity and cellular uptake. MDR1 siRNA could be used in multidrug resistance reversal in cancer therapy. siRNAs were encapsulated into NLPs consisted of mPEG-DSPE/DOTAP/DOPE [10:50:40 molar ratio] by the detergent dialysis method. The particle diameters of NLPs and their surface charge were measured using dynamic light scattering. siRNA encapsulation efficiency was determined by an indirect method via filtration and free siRNA concentration determination. NLPs cytotoxicity was investigated by MTT assay. The ability of NLPs for siRNA delivery checked in two human cell lines [MCF-7/ADR and EPP85-181/RDB] by fluorescence microscopy and compared with oligofectamine. NLPs containing MDR1 siRNA were prepared with the stable size of 80-90 nm and the zeta potential near to neutral. The siRNA encapsulation efficacy was more than 80%. These properties are suitable for in vivo siRNA delivery. NLPs cytotoxicity studies demonstrated they were non-toxic at the doses used. NLPs improved siRNA localization in both cell lines. NLPs containing MDR1 siRNA can be a good candidate for in vivo siRNA delivery studies
Subject(s)
Humans , RNA, Small Interfering , Lipids , Nanoparticles , Liposomes , Genetic TherapyABSTRACT
Elevated expression of the drug efflux transporter ABCG2 seems to correlate with multi-drug resistance of cancer cells. Specific COX-2 inhibitor celecoxib has been shown to enhance the sensitivity of cancer cells to anticancer drugs. To clarify whether ABCG2 inhibition is involved in the sensitizing effect of celecoxib, we investigated whether the expression of ABCG2 in breast cancer cell lines could be modulated by celecoxib. The expression of the multi-drug resistant gene [ABCG2] at mRNA and protein level was detected by real-time quantitative reverse transcription-polymerase chain reaction and flow cytometry analysis, respectively. Among three human breast cancer cell lines, ABCG2 and COX-2 were highly expressed in MCF7-MX and MDA-MB-231 cells, respectively. The COX-2 inhibitor celecoxib up-regulated the expression of ABCG2 mRNA in MCF-7 and MCF7-MX cells, which was accompanied by increased ABCG2 protein expression. While celecoxib was able to block the 12-O-tetradecanoylphorboL[-1]3-acetate [TPA]-mediated increase in COX-2 expression in MDA-MB-231 cells, it increased the expression of ABCG2 up to 4.27 times to the control level at mRNA level and with less intensity at protein level. Our findings provide evidence that celecoxib up-regulates ABCG2 expression in human breast cancer cells and proposed that ABCG2 is not involved in chemosensitizing effects of celecoxib
ABSTRACT
Doxorubicin [DOX], a widely used chemotherapeutic agent can give rise to serve cardiotoxicity by inducing apoptosis. Curcumin, the active compound of the rhizome of Curcuma longa L. has anti-inflammatory, antioxidant and anti-proliferative activities. Curcumin has been identified to increase cytotoxicity in several cancer cell lines in combination with DOX, but there is no study about its effect and DOX on normal cardiac cells. Therefore, in the present study, we evaluated the effect of curcumin on apoptosis induced by DOX in H9c2 rat heart-derived cells. Cell viability was determined by MTT assay. Also, activation of caspase-3 was evaluated by spectrophotometry. Quantitative real time RT-PCR was used to evaluate the expression of c-IAP1. Detection of intracellular DOX accumulation was performed by flow cytometry. No toxicity observed when the cells exposed for 1 hr to different concentrations of curcumin, but pretreatment of cells with curcumin increased cytotoxicity of DOX in a dose dependent manner. Analysis of caspase-3 activation showed that curcumin pretreatment increased caspase-3 activation. RT-PCR analysis clearly showed that curcumin significantly decreased mRNA gene expression of c-IAP1 compared to cells treated with DOX alone. Pretreatment of H9c2 cells with DOX and curcumin had no effect on the intracellular accumulation of DOX. Our observations indicated that subtoxic concentrations of curcumin sensitize H9c2 cells to DOX-induce apoptosis. These results suggest that the use of curcumin in combination with DOX in malignancy must be reevaluated