[show abstract][hide abstract] ABSTRACT: A quantum dot (QD)-bound hybridization probe was designed for detection of intracellular pre-miRNA using chitosan (CS)/poly(γ-glutamic acid) (γ-PGA) complex as a gene vector. The probe was prepared by assembling thiolated RNA to gold nanoparticle (Au NP) via Au-S bond and then binding 3'-end amine of the RNA to the carboxy group capped on quantum dot surface. The QD-RNA-Au NP probe was assembled on the vector by mixing with aqueous γ-PGA solution and then CS solution to construct a gene delivery system for highly effective cellular uptake and delivery. After the probe was released from CS/γ-PGA complex to the cytoplasm by electrostatic repulsion at intracellular pH, it hybridized with pre-miRNA precursor as target. The formed product was then cleaved by RNase III Dicer, leading to the separation of QDs from Au NPs and fluorescence emission of QDs, which could be detected by confocal microscopic imaging to monitor the amount of the intracellular pre-miRNA precursor. The in vitro assays revealed that the QD-RNA-Au NP was a robust, sensitive and selective probe for quantitative detection of target pre-miRNA. Using MDA-MB231 and MCF-7 breast cancer cells as models, the relative amount of pre-miRNA let-7a could be successfully compared. Since the amount of miRNA is related to the progress and prognosis of cancer, this strategy could be expected to hold promising application potential in medical research and clinical diagnostics.
PLoS ONE 01/2013; 8(6):e65540. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1) has been reported to play an important role in breast carcinogenesis. This work investigated the correlation of UHRF1 DNA level in plasma with clinical characteristics of breast cancer and its clinical significance in breast cancer diagnosis. The expression of UHRF1 in primary breast cancer tissue was examined by Western blot. The UHRF1 DNA levels in plasma and UHRF1 mRNA expression in tissues were determined by accurate real-time quantitative PCR. The associations of UHRF1 levels with clinical variables were evaluated using standard statistical methods. The UHRF1 DNA in plasma of 229 breast cancer patients showed higher expression than healthy controls, which showed high specificity up to 76.2% at a sensitivity of 79.2%, and was significantly associated with c-erbB2 positive status, cancer stage and lymph node metastasis. High UHRF1 DNA level in plasma was significantly associated with short progression-free survival. The UHRF1 DNA level in plasma is highly correlative with breast cancer and its status and stage, and may be a potential independent diagnostic and prognostic factor for both breast cancer and the survival of breast cancer patients.
[show abstract][hide abstract] ABSTRACT: A highly sensitive method was developed for detection of target DNA. This method combined circular strand-displacement polymerization (CSRP) with silver enhancement to achieve dual signal amplification. After molecular beacon (MB) hybridized with target DNA, the reporter gold nanoparticle (Au NPs) was attached to an electrode surface by hybridization between Au NP labeled primer and stem part of the MB to initiate a polymerization of DNA strand, which led to the release of target and another polymerization cycle. Thus the CSRP produced the multiplication of target-related reporter Au NPs on the surface. The Au NPs then catalyzed silver deposition for subsequent stripping analysis of silver. The dual signal amplification offered a dramatic enhancement of the stripping response. This signal could discriminate perfect matched target DNA from 1-base mismatch DNA. The dynamic range of the sequence-specific DNA detection was from 10(-16) to 10(-12)molL(-1) with a detection limit down to sub-femtomolar level. This proposed method exhibited an efficient amplification performance, and would open new opportunities for sensitive detection of other biorecognition events.
[show abstract][hide abstract] ABSTRACT: The UHRF1 gene plays important roles in both cell proliferation through its NIRF_N domains, a PHD domain, an SRA domain, and a RING domain, and multidrug resistance in breast cancer treatment. In this work, a short-hairpin RNA (shRNA) lentiviral system was introduced in two human breast cancer cell lines (MDA-MB-231 and MCF-7) to downregulate the expression of UHRF1 and study the specific inhibition of UHRF1 in breast cancer growth. The effect of UHRF1-shRNA on breast cancer cell proliferation was examined using methylthiazoletetrazolium, bromodeoxyuridine, and colony formation assays. The proliferative potential of the UHRF1-shRNA-treated cells showed a remarkable decrease. Moreover, the downregulation of UHRF1 in both breast cancer cell lines significantly inhibited the colony formation capacity. Results suggested that the inhibition of UHRF1 via an RNA interference lentiviral system may provide an effective way for breast cancer therapy.
Cancer Biotherapy & Radiopharmaceuticals 04/2011; 26(2):183-9. · 1.44 Impact Factor