Generation of directly reprogrammed human endothelial cells derived from fibroblast using ultrasound.

Physical microenvironment plays an important role in determining cellular reprogramming. In this study, we first generated directly reprogrammed human dermal fibroblasts (HDFs) into endothelial cells (ECs) mediated by environmental transition-guided cellular reprogramming (e/Entr) using ultrasound and characterized e/Entr. Ultrasound stimulus was introduced to ECs culture media and HDFs and induced into ECs-like cells. We performed microarray, RT-PCR, protein analysis, matrigel plug assay and e/Entr were transplanted into ischemic hindlimb mice model. Here we show that the activation of MAPK signaling pathways and the modulation of histone proteins such as Hp1-α, H3K27me3 and H3K4me3 in e/Entr contribute to the changes in chromatin configuration and reprogramming. Microarray data demonstrated that e/Entr highly expressed genes associated with ECs transcription factors and angiogenesis. In addition, the transplantation of e/Entr into hindlimb ischemia showed a high recovery of blood perfusion, limb salvage and e/Entr contributed to the formation of new vessels. In conclusion, the present study provided the first evidence that ultrasound reprogramming can induce postnatal cells to functional ECs. Therefore, our data suggest that physical stimulus-mediated reprogramming is a highly effective and safe strategy for the novel therapeutic alternatives.

Bioimaging of transcriptional activity of microRNA124a during neurogenesis.

OBJECTIVES: A special vector system was developed to monitor the in vitro and in vivo endogenous level of a primary transcript of miR124a during neuronal differentiation RESULTS: The upstream regions of miR124a were fused with luciferase (Gluc) and their activity was measured. During neurogenesis of P19 cells, the primary transcript level of miR124a was increased 1.5-times compared to the undifferentiated P19 cells. P19 cells grafted to nude mice exhibited the same pattern of luciferase activity in vivo as they did in vitro. CONCLUSION: The expression of primary miR124a during neurogenesis was successfully imaged by in vitro and in vivo luciferase reporter gene-based method.

Quantum dot-based molecular beacon to monitor intracellular microRNAs.

Fluorescence monitoring of endogenous microRNA (miRNA or miR) activity related to neuronal development using nano-sized materials provides crucial information on miRNA expression patterns in a noninvasive manner. In this study, we report a new method to monitor intracellular miRNA124a using quantum dot-based molecular beacon (R9-QD-miR124a beacon). The R9-QD-miR124a beacon was constructed using QDs and two probes, miR124a-targeting oligomer and arginine rich cell-penetrating peptide (R9 peptide). The miR124a-targeting oligomer contains a miR124a binging sequence and a black hole quencher 1 (BHQ1). In the absence of target miR124a, the R9-QD-miR124a beacon forms a partial duplex beacon and remained in quenched state because the BHQ1 quenches the fluorescence signal of the R9-QD-miR124a beacon. The binding of miR124a to the miR124a binding sequence of the miR124a-targeting oligomer triggered the separation of the BHQ1 quencher and subsequent signal-on of a red fluorescence signal. Moreover, enhanced cellular uptake was achieved by conjugation with the R9 peptide, which resulted in increased fluorescent signal of the R9-QD-miR124a beacons in P19 cells during neurogenesis due to the endogenous expression of miR124a.

Simultaneous imaging of two different cancer biomarkers using aptamer-conjugated quantum dots.

Studying gene expression profile in a single cancer cell is important because multiple genes are associated with cancer development. Quantum dots (QDs) have been utilized as biological probes for imaging and detection. QDs display specific optical and electrical properties that depend on their size that can be applied for imaging and sensing applications. In this study, simultaneous imaging of the cancer biomarkers, tenascin-C and nucleolin, was performed using two types of aptamer-conjugated QDs. The simultaneous imaging of these two different cancer markers in three cancer cell lines was reliable and cell line-specific. Current requirements for cancer imaging technologies include the need for simple preparation methods and the ability to detect multiple cancer biomarkers and evaluate their intracellular localizations. The method employed in this study is a feasible solution to these requirements.

Amphiphilic peptides with arginines and valines for the delivery of plasmid DNA.

A non-toxic and efficient gene carrier is one requirement for clinical gene therapy. In this study, amphiphilic peptides composed of arginines and valines were synthesized and characterized as plasmid DNA (pDNA) carriers. The peptides have a cationic region containing 1-4 arginines and a hydrophobic region containing 6 valines. The arginine-valine peptides (RV peptides) formed micelles in aqueous solution with a critical micelle concentration (CMC) of 1.35 mg/ml. In gel retardation assay, the RV peptides retarded all pDNA at weight ratios (pDNA:RV peptide) of 1:3 for R1V6, 1:2 for R2V6 and R3V6, and 1:1 for R4V6. A heparin competition assay showed that the R3V6 peptide formed tighter complexes with pDNA than poly-L-lysine (PLL). In vitro transfection assay into HEK293 cells showed that the R1V6 and R2V6 peptides had the highest transfection efficiencies at 1:30 weight ratios (pDNA:RV peptide), while the R3V6 and R4V6 peptides had the highest efficiencies at 1:20 weight ratios. Under optimal conditions, the R3V6 peptide had the highest transfection efficiency of all the RV peptides and PLL. MTT assay showed that the RV peptides did not have any detectable toxicity to cells. Therefore, the RV peptide may be useful for the development of non-toxic gene carriers.

Smart magnetic fluorescent nanoparticle imaging probes to monitor microRNAs.

An imaging system that can be used to evaluate the expression levels of microRNAs during neuronal development can provide noninvasive information for investigating a variety of biological phenomena related to microRNAs (miRNAs, miRs). Herein, the development of a novel imaging platform to monitor intracellular miR124a during neuronal differentiation is reported using rhodamine-coated cobalt ferrite magnetic fluorescent (MF) nanoparticles linked to a quenching molecular system containing an miR124a binding sequence (MF-miR124a beacon). During neuronal differentiation, in vitro fluorescence signals of the MF-miR124a beacon are significantly increased under conditions where miR124a is highly expressed, and dramatically return to the original quenched fluorescence after anti-miR124a treatment. In vivo fluorescence images show enhanced fluorescence signals in mice with P19 cells within a poly-L-lactic acid scaffold after induction of neuronal differentiation. In addition, magnetic resonance (MR) images provide in vivo tracking of cells containing the MF-miR124a beacon. These studies represent the first step toward the use of nanotechnological imaging of mature miRNA, and this technique could be used for cellular tracking with a MR imaging system as well as for simultaneous monitoring of the miRNA expression pattern in vivo.

Bioimaging of nucleolin aptamer-containing 5-(N-benzylcarboxyamide)-2'-deoxyuridine more capable of specific binding to targets in cancer cells.

Chemically modified nucleotides have been developed and applied into SELEX procedure to find a novel type of aptamers to fit with targets of interest. In this study, we directly performed chemical modification of 5-(N-benzylcarboxyamide)-2'-deoxyuridine (called 5-BzdU) in the AS1411 aptamer, which binds to the nucleolin protein expressed in cancer cells. Forty-seven compounds of AS1411-containing Cy3-labeled 5-BzdU (called Cy3-(5-BzdU)-modified-AS1411) were synthesized by randomly substituting thymidines one to twelve in AS1411 with Cy3-labeled 5-BzdU. Both statistically quantified fluorescence measurements and confocal imaging analysis demonstrated at least three potential compounds of interest: number 12, 29 and 41 that significantly increased the targeting affinity to cancer cells but no significant activity from normal healthy cells. These results suggest that the position and number of substituents in AS1411 are critical parameters to improve the aptamer function. In this study, we demonstrated that chemical modification of the existing aptamers enhanced the binding and targeting affinity to targets of interest without additional SELEX procedures.

In vitro derby imaging of cancer biomarkers using quantum dots.

Semiconductor quantum dots (QDs), which have broad absorption with narrow emission spectra, are useful for multiplex imaging. Here, fluorescence derby imaging using dual color QDs conjugated by the AS1411 aptamer (targeting nucleolin) and the arginine-glycine-aspartic acid (targeting the integrin alpha(v)beta(3)) in cancer cells is reported. Simultaneous fluorescence imaging of cellular distribution of nucleolin and integrin alpha(v)beta(3) using QDs enables easy monitoring of separate targets in the cancer cells and the normal healthy cells. These results suggest the feasibility of a concurrent visualization of QD-based multiple cancer biomarkers using small molecules such as aptamer or peptide ligands.

In vivo imaging of miR-221 biogenesis in papillary thyroid carcinoma.

PURPOSE: To investigate the overexpression of miR-221 in papillary thyroid carcinoma (PTC), we developed a Gaussia luciferase (Gluc) system regulated by miR-221. PROCEDURES: Quantities of primary or mature miR-221 in normal thyroid cells (HT-ori3) and in PTC (NPA, TPC-1) were measured by quantitative real-time polymerase chain reaction. Cytomegalovirus (CMV)/Gluc-3xPT_miR221, which included three perfect complementary target sequences repeats of miR221 in the 3'-untranslated region of Gluc, was transfected into cells with pre-miR-221 or anti-miR-221 and Gluc activities were then compared in vitro and in vivo. RESULTS: Primary or mature miR-221 were overexpressed in PTC as compared with HT-ori3. In cells transfected with the Gaussia luciferase reporter system (CMV/Gluc-3xPT_miR221), Gluc activities were regulated according to miR-221 levels in vitro and in vivo. CONCLUSIONS: These results suggest that the devised CMV/Gluc-3xPT_miR221 system may be a useful tool for monitoring quantities of endogenous miR-221 in cells or living organisms.

18F-FDG PET/CT in mediastinal lymph node staging of non-small-cell lung cancer in a tuberculosis-endemic country: consideration of lymph node calcification and distribution pattern to improve specificity.

PURPOSE: The aim of the study was to assess the accuracy of (18)F-fluorodeoxyglucose (FDG) PET/CT in mediastinal lymph node staging of patients with non-small-cell lung cancer (NSCLC) in a region with a high prevalence of granulomatous disease. METHODS: Between March 2004 and February 2006, all patients with NSCLC underwent FDG PET/CT and contrast-enhanced thoracic CT, and subsequent surgical resection. PET/CT and contrast-enhanced CT images of 182 patients (126 men and 56 women; mean age 60.7 years) with NSCLC were acquired. Mediastinal node staging was determined using the American Joint Committee on Cancer (AJCC) staging system. Surgical and histological findings served as the reference standard. RESULTS: A total of 182 patients with 778 mediastinal node stations were evaluated. Sensitivity and specificity of contrast-enhanced CT were 36% and 80% on a per-patient basis and 23% and 92% on a per-node station basis. Sensitivity and specificity of PET/CT were 81% and 73% on a per-patient basis and 75% and 85% on a per-node station basis. After lymph nodes with calcification and bilateral hilar distribution were considered benign, sensitivity and specificity of PET/CT were 75% and 89% on a per-patient basis and 66% and 96% on a per-node station basis. CONCLUSION: This prospective study suggests that FDG PET/CT can more accurately stage mediastinal lymph nodes than CT. Considering lymph node calcification and distribution pattern could improve specificity at the cost of a decrease in sensitivity.

Development of a quadruple imaging modality by using nanoparticles.

The combination of nanotechnology with molecular imaging has great potential for the development of diagnostics and therapeutics, and multimodal imaging enables versatile applications from cell tracking in animals to clinical applications. Herein, we report a multimodal nanoparticle imaging system that is capable of concurrent fluorescence, bioluminescence, bioluminescence resonance energy transfer (BRET), positron emission tomography (PET) and magnetic resonance (MR) imaging in vivo. A cobalt-ferrite nanoparticle surrounded by rhodamine (MF) was conjugated with luciferase (MFB) and p-SCN-bn-NOTA (2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclonane-1,4,7-triacetic acid) followed by (68)GaCl(3) (magnetic-fluorescent-bioluminescent-radioisotopic particle, MFBR). Confocal microscopy revealed good transfection efficiency of MFB into cells and BRET was also observed in MFB. A good correlation among rhodamine, luciferase, and (68)GaCl(3) was found in MFBR, and the activities of each imaging modality increased dose-dependently with the amount of MFBR in the C6 cells. In vivo optical images were acquired from the thighs of mice after intramuscular and subcutaneous injections of MFBR-laden cells. MicroPET and MR images showed intense radioactivity and ferromagnetic intensities with MFBR-laden cells. The multimodal imaging strategy could be used as potential imaging tools to track cells.

Theragnosis by a miR-141-3p molecular beacon: simultaneous detection and sensitization of 5-fluorouracil resistant colorectal cancer cells through the activation of the TRIM13-associated apoptotic pathway.

We developed a molecular beacon targeting miR-141-3p, aberrantly increased in 5-fluorouracil-resistant colorectal cancer cells (R-CRCCs). It consists of a fluorophore-labeled oligonucleotide, antisense to miR-141-3p, and a quencher. It detected R-CRCCs and recovered the chemosensitivity of them to 5-fluorouracil by hybridization with miR-141-3p, which is applicable to cancer treatment.

Bioimaging of the unbalanced expression of microRNA9 and microRNA9* during the neuronal differentiation of P19 cells.

Generally, the 3'-end of the duplex microRNA (miR) precursor (pre-miR) is known to be stable in vivo and serve as a mature form of miR. However, both the 3'-end (miR9) and 5'-end (miR9*) of a brain-specific miR9 have been shown to function biologically in brain development. In this study, real-time PCR analysis and in vitro/in vivo bioluminescent imaging demonstrated that the upstream region of a primary miR9-1 (pri-miR9-1) can be used to monitor the highly expressed pattern of endogenous pri-miR9-1 during neurogenesis, and that the Luciferase reporter gene can image the unequal expression patterns of miR9 and miR9* seen during the neuronal differentiation of P19 cells. This demonstrates that our bioimaging system can be used to study the participation of miRs in the regulation of neuronal differentiation.

In vivo imaging of functional targeting of miR-221 in papillary thyroid carcinoma.

UNLABELLED: MicroRNAs (miRNAs) are small, noncoding RNA molecules that control expression of target genes. The abnormally expressed miRNAs function as oncogenes or tumor suppressors in human cancer. To evaluate the abundant gene regulation of miR-221 in papillary thyroid carcinoma (PTC), we performed microarray analysis and developed a Gaussia luciferase (Gluc) reporter system regulated by miR-221. METHODS: Total RNAs were isolated from pre-miR-221-treated normal human thyroid cells (HT-ori3) and anti-miR-221-treated papillary thyroid cells (NPA). Microarray analysis was performed with 44,000 probes. The messenger RNA levels of target genes regulated by miR-221 were evaluated using reverse-transcription polymerase chain reaction. Three types of cytomegalovirus (CMV)/Gluc_3' untranslated region (UTR) of homeobox B5 (HOXB5), which included a seed sequence of mature miR-221 in the 3' UTR of HOXB5 after the Gluc stop codon, were transfected into NPA cells, and pre-miR-221 was cotransfected with CMV/Gluc_3' UTR of HOXB5. The Gluc activities in cells were measured by luciferase assay. Mice implanted with PTC-expressing Gluc regulated by miR-221 were monitored with bioluminescence imaging for 6 d. RESULTS: Microarray analysis showed thousands of genes were directly and indirectly regulated by miR-221 and shifted the gene expression pattern of normal thyroid cells toward PTC. Of several genes downregulated more than 2-fold by miR-221, messenger RNA levels of HOXB5 were significantly downregulated by miR-221. Also, in vitro or in vivo Gluc activities using CMV/Gluc_3' UTR of HOXB5 systems were downregulated dose dependently by endogenous or exogenous miR-221. CONCLUSION: MiR-221 overexpressed in PTC drives carcinoma gene expression patterns by directly and indirectly regulating numerous genes, including HOXB5. The bioluminescence imaging system using CMV/Gluc_3' UTR of HOXB5 is a useful tool for noninvasive in vivo long-term monitoring of functional targeting of miR-221.

Development of a dual-luciferase reporter system for in vivo visualization of MicroRNA biogenesis and posttranscriptional regulation.

UNLABELLED: MicroRNAs (miRNAs) function in mammalian cells via translational repression or messenger RNA (mRNA) cleavage of target genes by base-pairing with 3' untranslated regions (UTRs) of target mRNAs. Although miRNAs are involved in cell differentiation or organ development, posttranscritptional regulation of miRNA is not well understood. Here, we developed a dual-luciferase reporter system for monitoring in vivo endogenous transcription of primary miRNA (pri-miRNA) and also the mature miRNA activity simultaneously. METHODS: miR23P639/Fluc plasmid carrying firefly luciferase (Fluc) under the control of miR-23a promoter was used to monitor the transcriptional level of miR-23a, and a cytomegalovirus (CMV)/Gluc/3xPT_mir23 recombinant containing 3 copies of the target sequence of miR-23a in the 3' UTR of Gaussia luciferase (Gluc) before the poly(A) tail was used to monitor the targeting activity of mature miR-23a. This dual-luciferase reporter system transfected to the same population of cells was used to monitor the increased transcriptional level of the pri-miR-23a reflected in the Fluc activity and the decreased Gluc activity affected by mature miR-23a action. Fluc and Gluc activities were also imaged in vivo using the respective substrates in grafted cells in the same nude mice using an in vivo bioluminescence imager. RESULTS: In HeLa cells and undifferentiated P19 cells, the increased Fluc activity representing the primary miR-23a transcript level reflected the resultant increase in repression of Gluc activity representing mature miR-23a activity. However, 293 cells showed Gluc activity was not repressed as much as Fluc activity was increased, suggesting a block in the posttranscriptional processing of miR-23a transcript in 293 cells. The miR-23a expression in P19 cells before and after neuronal differentiation with retinoic acid treatment showed an increase in Fluc activity and a concomitant decrease in Gluc activity in vitro. HeLa, 293 cells and undifferentiated P19 cells grafted to the nude mice showed exactly the same pattern of luciferase activities in vivo and in vitro. CONCLUSION: We developed a dual-luciferase reporter system to monitor expression and posttranscriptional regulation of a miR-23a in cells in vitro and in vivo. This dual-luciferase reporter system is intended to be used to monitor the expression and regulation of miRNAs noninvasively, especially to understand the differentiation of grafted cells in vivo.

Noninvasive in vivo monitoring of neuronal differentiation using reporter driven by a neuronal promoter.

PURPOSE: We imaged neuronal differentiation in vivo using dual reporters (sodium iodide symporter [NIS] and luciferase) coupled to a neuron-specific enolase (NSE) promoter. METHODS: PC12 (NSE positive) and F11 cells were transfected with a bicistronic (NIS and luciferase; pNSE-NF) or a luciferase (pNSE-Fluc) reporter coupled to the NSE promoter. Weak NSE promoter activity was overcome by a two-step transcriptional amplification (TSTA) system (pNSE-TSTA-Fluc). In vivo, NIS and luciferase expression were examined using a (99m)Tc-pertechnetate gamma camera and bioluminescence imaging, respectively. RESULTS: pNSE-NF-transfected PC12 cells showed 3-fold higher radioiodine uptakes and >100-fold higher luciferase activity than parental cells. NIS or luciferase activity was not detected in pNSE-NF-transfected HeLa cells. When F11 cells were differentiated into neurons by db-cAMP, NIS and luciferase activities increased 4-fold compared to those without treatment, which was confirmed by Western blot and RT-PCR of NSE. In vivo in pNSE-NF-transfected F11 cells, db-cAMP treatment increased the luciferase activity but not the scintigraphic activity. In vitro, pNSE-TSTA-Fluc produced 130-fold higher luciferase activity than pNSE-Fluc and neuronal differentiation showed 4-fold higher activity from both pNSE-TSTA-Fluc and pNSE-Fluc than before differentiation. In vivo, in pNSE-TSTA-Fluc-transfected F11 cells, luciferase activity increased after neuronal differentiation. In vivo luciferase activity persisted up to 2 days after db-cAMP-induced neuronal differentiation. CONCLUSION: NSE promoter-driven dual reporter transgenes revealed the possibility of in vivo imaging of neuronal differentiation, which was further enabled by high amplification using a TSTA system. We propose that this strategy be used to follow the transplanted stem cells during differentiation in live animals.

Exosome-Mediated Ultra-Effective Direct Conversion of Human Fibroblasts into Neural Progenitor-like Cells.

Exosomes, naturally secreted nanoparticles, have been introduced as vehicles for horizontal transfer of genetic material. We induced autologous exosomes containing a cocktail of reprogramming factors ("reprosomes") to convert fibroblasts into neural progenitor cells (NPCs). The fibroblasts were treated with ultrasound and subsequently cultured in neural stem cell medium for 1 day to induce the release of reprosomes composed of reprogramming factors associated with chromatin remodeling and neural lineage-specific factors. After being treated with reprosomes, fibroblasts were converted into NPCs (rNPCs) with great efficiency via activation of chromatin remodeling, so quickly that only 5 days were required for the formation of 1500 spheroids showing an NPC-like phenotype. The rNPCs maintained self-renewal and proliferative properties for several weeks and successfully differentiated into neurons, astrocytes, and oligodendrocytes in vitro and in vivo. Reprosome-mediated cellular reprogramming is simple, safe, and efficient to produce autologous stem cells for clinical application.

Development of a dual membrane protein reporter system using sodium iodide symporter and mutant dopamine D2 receptor transgenes.

UNLABELLED: For noninvasive monitoring of cellular status by dual reporters, a dual membrane protein reporter system was developed and its in vivo applicability was examined. Human sodium iodide symporter (hNIS) and mutant dopamine D(2) receptor (D(2)R) transgenes were chosen considering their complementarity. METHODS: pIRES-hNIS/D(2)R containing NIS and D(2)R linked with an internal ribosomal entry site (IRES) was constructed and transfected into human hepatoma SK-Hep1 and rat glioma C6 cells. The cell lines stably expressing hNIS and D(2)R (named SK-ND and C6-ND) were produced, which was confirmed by messenger RNA expression of reporter genes. The functional activities of hNIS and D(2)R were measured by (125)I uptake assay and (3)H-spiperone receptor-binding assays. A biodistribution study was performed on SK-ND tumor-bearing mice using (99m)Tc-pertechnetate and (3)H-spiperone. In vivo hNIS expression was examined using (99m)Tc-pertechnetate gamma-camera imaging and, D(2)R expression was examined using a (3)H-spiperone autoradiographic study. RESULTS: (125)I uptake of SK-ND and C6-ND cell lines showed a maximum 97-fold and 43-fold increase, respectively, which were completely inhibited by KClO(4). Specific (3)H-spiperone binding to SK-ND and C6-ND cell homogenates was observed, which were completely inhibited by (+)-butaclamol. Among the dual reporter gene-expressing cell lines, the activities of both reporters were inversely correlated with each other. Competition assay of hNIS-expressing cells by D(2)R vector transfection and D(2)R-expressing cells by hNIS vector transfection showed a dose-dependent decrease of hNIS and D(2)R activities, respectively. In the biodistribution study, (99m)Tc-pertechnetate accumulated 10-fold and (3)H-spiperone accumulated 4-fold more in SK-ND tumors than that in parental SK tumors. In vivo imaging of (99m)Tc-pertechnetate persisted until 5 wk after the cell graft in SK-ND tumors. Autoradiographic study of brain tissues from these mice also revealed an accumulation of (3)H-spiperone in SK-ND tumors. CONCLUSION: We developed a dual membrane-bound positron and gamma-imaging reporter system of hNIS and D(2)R. We observed its reporting capability in vitro and in vivo and elucidated that these 2 membrane protein reporters competed with each other in their expression. Although we expect that hNIS and D(2)R transgenes can complement each other as a dual reporter system, we suggest that one needs to validate the ratio of expression of the 2 membrane protein reporter transgenes for cellular status tracking.

An ultra-effective method of generating extramultipotent cells from human fibroblasts by ultrasound.

Multipotent cells have similar basic features of all stem cells but limitation in ability of self-renewal and differentiation compared with pluripotent cells. Here, we have developed an ultra effective, gene- and chemical-free method of generating extra multipotent (xpotent) cells which have differentiation potential more than limited cell types, by the mechanism of ultrasound-directed permeation of environmental transition-guided cellular reprogramming (Entr). Ultrasound stimulus generated a massive number of Entr-mediated xpotent (x/Entr) spheroids from human dermal fibroblasts (HDFs) 6 days after treatment. The emergence of x/Entr was first initiated by the introduction of human embryonic stem cell (ESC) environments into the HDFs to start fast cellular reprogramming including activation of stress-related kinase signaling pathways, subsequent chromatin remodeling, and expression of pluripotent-related genes via transient membrane damage caused by ultrasound-induced cavitation. And then, pluripotent markers were transported into their adjacent HDFs via direct cell-to-cell connections in order to generate xpotent clusters. The features of x/Entr cells were intermediate between pluripotency and multipotency in terms of pluripotency with three germ layer markers, multi-lineage differentiation potential, and no teratoma formation. This physical stimulus-mediated reprogramming strategy was cost-effective, simple, quick, produced significant yields, and was safe, and can therefore provide a new paradigm for clinical application.

Bioimaging of multiple piRNAs in a single breast cancer cell using molecular beacons.

Simultaneous bioimaging of piR-36026 and piR-36743 using molecular beacons successfully visualized 4 different subtypes of breast cancer.