Prominin-1 controls stem cell activation by orchestrating ciliary dynamics.

Proper temporal and spatial activation of stem cells relies on highly coordinated cell signaling. The primary cilium is the sensory organelle that is responsible for transmitting extracellular signals into a cell. Primary cilium size, architecture, and assembly-disassembly dynamics are under rigid cell cycle-dependent control. Using mouse incisor tooth epithelia as a model, we show that ciliary dynamics in stem cells require the proper functions of a cholesterol-binding membrane glycoprotein, Prominin-1 (Prom1/CD133), which controls sequential recruitment of ciliary membrane components, histone deacetylase, and transcription factors. Nuclear translocation of Prom1 and these molecules is particularly evident in transit amplifying cells, the immediate derivatives of stem cells. The absence of Prom1 impairs ciliary dynamics and abolishes the growth stimulation effects of sonic hedgehog (SHH) treatment, resulting in the disruption of stem cell quiescence maintenance and activation. We propose that Prom1 is a key regulator ensuring appropriate response of stem cells to extracellular signals, with important implications for development, regeneration, and diseases.

Lipid-polymer nanoparticles with CD133 aptamers for targeted delivery of all-trans retinoic acid to osteosarcoma initiating cells.

Osteosarcoma, a common type of bone cancer in children, and represents an aggressive and fetal cancer worldwide. Osteosarcoma initiating cells are considered to be a subpopulation of cancer cells which contribute to the progression, recurrence, metastasis and multi-drug resistance of osteosarcoma. CD133 is considered to be one marker for osteosarcoma initiating cells. All-trans retinoic acid (ATRA), an active metabolite of vitamin A under the family retinoid, is an up-and-coming drug which was able to effectively treat various cancer initiating cells. Nevertheless, there have been no research that reported the activity of ATRA against osteosarcoma initiating cells. In this research, we hereby examined the potential activity of ATRA in osteosarcoma initiating cells, and developed lipid-polymer nanoparticles with CD133 aptamers for targeted ATRA delivery to osteosarcoma initiating cells. Using the cytotoxicity assay, colony formation assay, tumorsphere formation assay and flow cytometry, the therapeutic effect of ATRA and ATRA-loaded lipid-polymer nanoparticles conjugated with CD133 aptamers (ATRA-PLNP-CD133) against osteosarcoma initiating cells were investigated. The results showed that ATRA exerted potent activity towards osteosarcoma initiating cells. ATRA-PLNP-CD133, which showed a size of 129.9 nm and a sustained release of ATRA during 144 h, was demonstrated to efficiently and specifically promote the ATRA delivery to osteosarcoma initiating cells, and achieve superior therapeutic efficacy in osteosarcoma compared with ATRA and non-targeted nanoparticles. This is the first report of the therapeutic efficacy of ATRA towards osteosarcoma initiating cells, and the increased ATRA delivery by nanoparticles to osteosarcoma initiating cells using CD133 aptamers. ATRA-PLNP-CD133 represent an up-and coming approach for the therapy of osteosarcoma initiating cells.

Development of a novel and economical agar-based non-adherent three-dimensional culture method for enrichment of cancer stem-like cells.

BACKGROUND: Non-adherent or ultra-low attachment three-dimensional (3D) culture, also called sphere formation assay, has been widely used to assess the malignant phenotype and stemness potential of transformed or cancer cells. This method is also popularly used to isolate the cancer stem-like cells (CSCs) or tumor-initiating cells based on their unique anchorage-independent growth or anoikis-resistant capacity. Different non-adhesive coating agents, such as poly-2-hydroxyethyl methacrylate (poly-HEMA) and synthetic hydrogels, have been used in this non-adherent 3D culture. However, preparation of non-adherent culture-ware is labor-intensive and technically demanding, and also costs of commercial non-adherent culture-ware prepared with various coating agents are relatively expensive and the culture-ware cannot be used repeatedly. METHODS: In this study, we developed a non-adherent 3D culture method based on agar coating for growing tumor spheres derived from various cancer cell lines and primary prostate cancer tissues under a non-adherent and serum-free condition. The tumor spheres generated by this 3D culture method were analyzed on their expression profiles of CSC-associated markers by reverse transcription quantitative polymerase chain reaction, presence and relative proportion of CSCs by fluorescence-activated cell sorting (CD133+/CD44+ cell sorting) and also a CSC-visualizing reporter system responsive to OCT4 and SOX2 (SORE6), and in vivo tumorigenicity. The repeated use of agar-coated plates for serial passages of tumor spheres was also evaluated. RESULTS: Our results validated that the multicellular tumor spheres generated by this culture method were enriched of CSCs, as evidenced by their enhanced expression profiles of CSC markers, presence of CD133+/CD44+ or SORE6+ cells, enhanced self-renewal capacity, and in vivo tumorigenicity, indicating its usefulness in isolation and enrichment of CSCs. The agar-coated plates could be used multiple times in serial passages of tumor spheres. CONCLUSIONS: The described agar-based 3D culture method offers several advantages as compared with other methods in isolation of CSCs, including its simplicity and low-cost and repeated use of agar-coated plates for continuous passages of CSC-enriched spheres.

Inhibition of Growth and Metastasis of Colon Cancer by Delivering 5-Fluorouracil-loaded Pluronic P85 Copolymer Micelles.

Hepatic metastasis is the leading cause of mortality of colon cancer, which is still lack of an effective therapy. A new delivery system, pluronic P85 block copolymers, conveying chemotherapeutic agent 5-fluorouracil (5-Fu) for inhibiting growth and metastasis of colon cancer was designed and developed. In this study, we demonstrated that 5-Fu produce strong pesticide effect at lower doses in the present of pluronic P85 compared with control groups. The migration and invasion of HCT116 cells and RKO cells were examined and the results showed that migration and invasion capacities of HCT116 cells and RKO cells were reduced by administering 5-Fu/P85 copolymer micelles in vitro and in vivo which indicating an effectively activity. Interestingly, the content of CD133 + CXCR4+ cells in HCT116 cancer cells and RKO cells treated by 5-Fu/P85 copolymer micelles was decreased. Importantly, the epithelial-mesenchymal transition (EMT) of CD133 + CXCR4+ cells, which was strongly associated with liver metastasis of colon cancer, was also suppressed by giving 5-Fu/P85 copolymer micelles. The results indicated that 5-Fu/P85 copolymer micelles could inhibit the growth and metastasis of colon cancer, which could be attributed to the decrease of the content of CD133 + CXCR4+ cells and suppression of EMT of CD133 + CXCR4+ cells.