In the most common primary brain tumors, malignant glioma cells invade the extracellular matrix (ECM) and proliferate rapidly in the cerebral tissue, which is mainly composed of hyaluronan (HA) along with the elastin present in the basement membrane of blood vessels. To determine the role of ECM components in the invasive capacity of glioma cell lines, we developed a 3-D cell-culture system, based on a hydrogel in which HA can be coreticulated with kappa-elastin (HA-kappaE). Using this system, the invasiveness of cells from four glioma cell lines was dramatically increased by the presence of kappaE and a related, specific peptide (VGVAPG)(3). In addition, MMP-2 secretion increased and MMP-12 synthesis occurred. Extracellular injections of kappaE or (VGVAPG)(3) provoked a pronounced and dose-dependent increase in [Ca(2+)](i). kappaE significantly enhanced the expression of the genes encoding elastin-receptor and tropoelastin. We propose the existence of a positive feedback loop in which degradation of elastin generates fragments that stimulate synthesis of tropoelastin followed by further degradation as well as migration and proliferation of the very cells responsible for degradation. All steps in this ECM-based loop could be blocked by the addition of either of the EBP antagonists, lactose, and V-14 peptide, suggesting that the loop itself should be considered as a new therapeutic target.

The study of Mn-based superoxide dismutase mimic conjugated with a multimodal Re-probe in a cellular model of oxidative stress revealed that its bioactivity is associated with its accumulation at the mitochondria.

We have developed a straightforward synthetic pathway to a set of six photoactivatable G-quadruplex ligands with a validated G4-binding motif (the bisquinolinium pyridodicarboxamide PDC-360A) tethered through various spacers to two different photo-cross-linking groups: benzophenone and an aryl azide. The high quadruplex-versus-duplex selectivity of the PDC core was retained in the new derivatives and resulted in selective alkylation of two well-known G-quadruplexes (human telomeric G4 and oncogene promoter c-myc G4) under conditions of harsh competition. The presence of two structurally different photoactivatable functions allowed the selective alkylation of G-quadruplex structures at specific nucleobases and irreversible G4 binding. The topology and sequence of the quadruplex matrix appear to influence strongly the alkylation profile, which differs for the telomeric and c-myc quadruplexes. The new compounds are photoactive in cells and thus provide new tools for studying G4 biology.

G-Quadruplex(es) (G4) are noncanonical nucleic-acid structures found in guanine-rich sequences. They can be targeted with small molecules (G4 ligands) acting as reporters, for tracking both in vitro and in cells. We explored the cellular localization of PhenDC , one of the most powerful G4 ligands, by synthesizing two clickable azide and alkyne derivatives (PhenDC -alk, PhenDC -az) and labeling them in situ with the corresponding Cy5 click partners. A careful comparison of the results obtained for the copper-based CuAAC and copper-free SPAAC methodologies in fixed cells implicated Cu /alkyne intermediates in the nonspecific localization of ligands (and fluorophores) to the nucleoli. By contrast, SPAAC yielded similar nucleoplasmic labeling patterns in fixed and live cells. Our findings demonstrate the need for great care when using CuAAC to localize drugs in cells, and show that SPAAC gives results that are more consistent between fixed and live cells.

In order to avoid side effects at the time of cancer eradication to the patients, the selectivity of treatments has become of strategic importance. In the case of photodynamic therapy (PDT), two-photon absorption combined with active targeting of tumors could allow both spatial and chemical selectivity. In this context, we present the synthesis, spectroscopic, and biological properties of a series of porphyrin-triphenylamine hybrids with excellent singlet oxygen production capacities and good two-photon absorption.

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Bis-naphthalene macrocycles, which bind with high affinity and selectivity to abasic sites in DNA, efficiently inhibit their cleavage by APE1 (IC50 = 55-60 nM in the kinetic assay with a model THF substrate). These results demonstrate that substrate masking by non-covalent abasic-site ligands is an efficient strategy for inhibition of APE1.