Pharmacologic inhibition of the CK2-mediated phosphorylation of B23/NPM in cancer cells selectively modulates genes related to protein synthesis, energetic metabolism, and ribosomal biogenesis.

B23/NPM is a multifunctional nucleolar protein frequently overexpressed, mutated, or rearranged in neoplastic tissues. B23/NPM is involved in diverse biological processes and is mainly regulated by heteroligomer association and posttranslational modification, phosphorylation being a major posttranslational event. While the role of B23/NPM in supporting and/or driving malignant transformation is widely recognized, the particular relevance of its CK2-mediated phosphorylation remains unsolved. Interestingly, the pharmacologic inhibition of such phosphorylation event by CIGB-300, a clinical-grade peptide drug, was previously associated to apoptosis induction in tumor cell lines. In this work, we sought to identify the biological processes modulated by CIGB-300 in a lung cancer cell line using subtractive suppression hybridization and subsequent functional annotation clustering. Our results indicate that CIGB-300 modulates a subset of genes involved in protein synthesis (ES = 8.4, p < 0.001), mitochondrial ATP metabolism (ES = 2.5, p < 0.001), and ribosomal biogenesis (ES = 1.5, p < 0.05). The impairment of these cellular processes by CIGB-300 was corroborated at the molecular and cellular levels by Western blot (P-S6/P-4EBP1, translation), confocal microscopy (JC-1, mitochondrial potential), qPCR (45SrRNA/p21, ribosome biogenesis), and electron microscopy (nucleolar structure, ribosome biogenesis). Altogether, our findings provide new insights on the potential relevance of the CK2-mediated phosphorylation of B23/NPM in cancer cells, revealing at the same time the potentialities of its pharmacological manipulation for cancer therapy. Finally, this work also suggests several candidate gene biomarkers to be evaluated during the clinical development of the anti-CK2 peptide CIGB-300.

Microarray and nanotechnology applications of functional nanoparticles.

Microarrays are a sensitive, specific, miniaturized devices that may be used to detect selected DNA sequences and proteins, or mutated genes associated with human diseases. Several methods have been developed to detect the binding of complementary molecules to microarrays by generating an optical signal. One of the most commonly used molecular labeling methods at present is fluorescence, but its application is expensive due to sophisticated equipment required to design the platform, hybridize it, and interpret the images derived from microarray-based studies. This is a drawback for its use in laboratories and clinical services. Another less expensive procedure having similar sensitivity and specificity is DNA and protein functional nanoparticles (FNP). Nanoparticles are sphere-like biocompatible materials made of inert silica, metal or crystals of a nanometer in size, which are generally coated with a thin gold layer. They may be used as hybridization probes in single nucleotide polymorphism (SNP) screening and to detect biological markers for cancer, infection, and cardiovascular diseases.