Expression analysis of progesterone­regulated miRNAs in cells derived from human glioblastoma.

Glioblastomas (GBMs) are the most frequent and malignant type of brain tumor. It has been reported that progesterone (P4) regulates the progression of GBMs by modifying the expression of genes that promote cell proliferation, migration and invasion; however, it is not fully understood how these processes are regulated. It is possible that P4 mediates some of these effects through changes in the microRNA (miRNA) expression profile in GBM cells. The present study investigated the effects of P4 on miRNAs expression profile in U­251MG cells derived from a human GBM. U­251MG cells were treated for 6 h with P4, RU486 (an antagonist of the intracellular progesterone receptor), the combined treatment (P4+RU486) and cyclodextrin (vehicle) and then a miRNA microarray analysis conducted. The expression analysis revealed a set of 190 miRNAs with differential expression in the treatments of P4, RU486 and P4+RU486 in respect to the vehicle and P4 in respect to P4+RU486, of which only 16 were exclusively regulated by P4. The possible mRNA targets of the miRNAs regulated by P4 could participate in the regulation of proliferation, cell cycle progression and cell migration of GBMs. The present study provided insight for understanding epigenetic modifications regulated by sex hormones involved in GBM progression, and for identifying potential therapeutic strategies for these brain tumors.

Prostate Cancer Spheroids: A Three-Dimensional Model for Studying Tumor Heterogeneity.

Prostate cancer is one of the main causes of cancer and the sixth cause of death among men worldwide. One of the major challenges in prostate cancer research is cell heterogeneity defined as the different genomic and phenotypic characteristics in each individual cell making more difficult to assess the proper prostate cancer diagnosis and therapy. Tumor 3D spatial arrangement allow a strong interaction between the different cellular lineages and components which modulate cell proliferation, differentiation, and morphology. Prostate cancer spheroids are a cellular model which is capable to mimic the mechanical tensions of tumor tissue, providing a more representative pathophysiological model than the use of conventional 2D culture. Here, we describe a protocol to develop a 3D model of spheroids using prostate cancer cell lines (LNCaP, PC3, VCaP) which can be used to improve research considering tumoral heterogeneity role in cancer development, prognosis, and therapy.

Cell-Internalization SELEX of RNA Aptamers as a Starting Point for Prostate Cancer Research.

In the treatment of cancer, over the last decade different drugs delivery systems have been developed to increase therapeutic specificity to improve drug's efficacy, and safety by increasing bioavailability. Among these systems, small nucleic acid molecules with a three-dimensional structure, known as aptamers, have shown several advantages. Several approaches to design aptamers require modifications from starting libraries of DNA sequences. Here, we describe cell-internalization SELEX (Systematic Evolution of Ligands by Exponential Enrichment), a sophisticated technique based on RNA aptamers as a starting point, that enables design functional aptamers as drug-delivery tools. This variation of the original SELEX technique using RNA aptamers instead DNA aptamers allows to obtain aptamers that are internalized in prostate cancer cells using as a starting point an RNA aptamer library with 76 nucleotides. The major advantage of this technique is that modifications are not required in the initial library, as initial T7 transcription promoter or 2'F nucleotides before sequencing.