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Breast cancer is a heterogeneous disease, with a morbidity rate of 27.8% and a mortality rate of 15% among women population worldwide. Understanding how this cancer develops and the mechanisms behind tumor progression and chemoresistance is of utmost importance. Exosomes mediate communication in a population of heterogeneous tumoral cells. They have a cargo composed of oncogenes and oncomiRs which change the transcriptomic scenario of their targeted cells and activate numerous tumor‐promoting signaling pathways. Exosomes secreted by breast cancer cells lead to enhanced cell proliferation, replicative immortality, angiogenesis, invasion, migration, and chemoresistance. Studying exosomes from this perspective offers more in depth understanding of breast malignancy and may aid in the future development of early diagnostic, prognostic and therapeutic options. We present the latest findings in this area and offer practical solutions which may further stimulate the much‐needed research of exosome in breast cancer. [ABSTRACT FROM AUTHOR]

In this work, two new phenothiazinium dyes containing N -piperidinyl-carbinol auxochrome units have been designed, synthesized and investigated in vitro for ovarian cancer cell fluorescence imaging and cytotoxicity. A solvent free mechanochemical procedure is described as a greener alternative to the previously reported synthetic methodology applied in the preparation of methylene blue analogues by the substitution of the phenothiazinium tetraiodide substrate with nucleophilic secondary amines in solution. The optical properties of the new dyes were evaluated by UV–vis absorption/emission spectroscopy which revealed maxima situated in the red region (λ max absorption = 668-664 nm and λ max emission = 715-698 nm) with large molar extinction coefficients (log ε = 4.5–5.1) and bathochromic shifts of 314–383 cm−1 occurring upon switching from less polar to more polar solvents. The theoretical DFT computational study performed in order to clarify the obtained data indicated that the vertical TD-DFT calculations (typically applied for simulating UV–vis spectra) were within ∼150 nm of the experimental data, but a better agreement with experiment was obtained by using the vibronic corrections which revealed a dominant vibronic component not only for the main absorption/emission maxima, but also for the displayed shoulders which are rather the effects of the vibronic coupling between S 0 and S 1 electronic states. The new dyes presented a hydrophilic character (logP n -octanol/water = −1.15 and −1.29 respectively) comparable to the parent methylene blue and no aggregation tendency was observed in aqueous solution at concentration range 75–150 μM used in this study. Cellular imaging experiments displayed the new dyes' ability to selectively stain the cytoplasm of tumoral OVCAR-3 and A2780 fixed cells. The evaluation of their biological activity encompassed cell grow inhibitory potential (dose-response activity and half maximal inhibitory concentration IC 50), as well as their capacity to influence the tumoral OVCAR-3, A2780 and healthy BJ ovarian cells' metabolic activity. Dye 2 exhibited moderate cytotoxicity against human ovarian cancer cell lines, being the most active against the A2780 ovarian adenocarcinoma cells where its cellular uptake was noteworthy and displayed a deeper influence on the chemoresistant, highly malignant OVCAR-3 cells function by modulating FOLR1, ICAM-1 and VCAM-1 proteins with role in the growth and migration of cancer cells. [Display omitted] • New symmetrical Phenothiazinium dyes containing N-piperidinyl-carbinol auxochrome. • Solvent free mechanochemical procedure for the synthesis of MB analogues. • Optical properties enlightened by theoretical TD-DFT calculations with vibronic correction. • In vitro cytoplasmatic accumulation and staining of ovarian tumor cell lines. • Cytotoxicity and multitarget influence on ovarian tumor cell's functions. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) is a highly aggressive phenotype that is resistant to standard therapy. Thus, the development of alternative therapeutic strategies for TNBC is essential. The purpose of our in vitro study was to evaluate the impact of p53 gene silencing in conjunction with the administration of a natural compound, epigallocatechingallate (EGCG). RT2Profiler PCR Array technology was used to evaluate the impact of dual treatment on the main genes involved in apoptosis in the Hs578T cell culture model of TNBC. Gene expression analysis revealed 28 genes were significantly altered (16 upregulated and 12 downregulated) in response to combined p53 siRNA and EGCG treatment. Further analysis revealed that p53 siRNA and EGCG dual therapy leads to the activation of pro-apoptotic genes and the inhibition of pro-survival genes, autophagy, and cell network formation. These results indicate that this dual therapy targets both the apoptotic and angiogenic pathways, which may improve treatment effectiveness for tumors resistant to conventional treatment. [ABSTRACT FROM AUTHOR]

The synthesis, characterization and cytotoxic activity against different cancer cell lines of various mesoporous silica-based materials containing folate targeting moieties and a cytotoxic fragment based on a triphenyltin(IV) derivative have been studied. Two different mesoporous nanostructured silica systems have been used: firstly, micronic silica particles of the MSU-2 type and, secondly, mesoporous silica nanoparticles (MSNs) of about 80 nm. Both series of materials have been characterized by different methods, such as powder X-ray diffraction, X-ray fluorescence, absorption spectroscopy and microscopy. In addition, these systems have been tested against four different cancer cell lines, namely, OVCAR-3, DLD-1, A2780 and A431, in order to observe if the size of the silica-based systems and the quantity of incorporated folic acid influence their cytotoxic action. The results show that the materials are more active when the quantity of folic acid is higher, especially in those cells that overexpress folate receptors such as OVCAR-3 and DLD-1. In addition, the study of the potential modulation of the soluble folate receptor alpha (FOLR1) by treatment with the synthesized materials has been carried out using OVCAR-3, DLD-1, A2780 and A431 tumour cell lines. The results show that a relatively high concentration of folic acid functionalization of the nanostructured silica together with the incorporation of the cytotoxic tin fragment leads to an increase in the quantity of the soluble FOLR1 secreted by the tumour cells. In addition, the studies reported here show that this increase of the soluble FOLR1 occurs presumably by cutting the glycosyl-phosphatidylinositol anchor of membrane FR-α and by the release of intracellular FR-α. This study validates the potential use of a combination of mesoporous silica materials co-functionalized with folate targeting molecules and an organotin(IV) drug as a strategy for the therapeutic treatment of several cancer cells overexpressing folate receptors. [ABSTRACT FROM AUTHOR]