Cell Uptake of Steroid-BODIPY Conjugates and Their Internalization Mechanisms: Cancer Theranostic Dyes.

Estradiol-BODIPY linked via an 8-carbon spacer chain and 19-nortestosterone- and testosterone-BODIPY linked via an ethynyl spacer group were evaluated for cell uptake in the breast cancer cell lines MCF-7 and MDA-MB-231 and prostate cancer cell lines PC-3 and LNCaP, as well as in normal dermal fibroblasts, using fluorescence microscopy. The highest level of internalization was observed with 11ß-OMe-estradiol-BODIPY 2 and 7α-Me-19-nortestosterone-BODIPY 4 towards cells expressing their specific receptors. Blocking experiments showed changes in non-specific cell uptake in the cancer and normal cells, which likely reflect differences in the lipophilicity of the conjugates. The internalization of the conjugates was shown to be an energy-dependent process that is likely mediated by clathrin- and caveolae-endocytosis. Studies using 2D co-cultures of cancer cells and normal fibroblasts showed that the conjugates are more selective towards cancer cells. Cell viability assays showed that the conjugates are non-toxic for cancer and/or normal cells. Visible light irradiation of cells incubated with estradiol-BODIPYs 1 and 2 and 7α-Me-19-nortestosterone-BODIPY 4 induced cell death, suggesting their potential for use as PDT agents.

Manganese(I) tricarbonyl complexes as potential anticancer agents.

The antiproliferative activity of [Mn(CO)3(N^N)Br] (N^N = phendione 1, bipy 3) and of the two newly synthesized Mn complexes [Mn(CO)3(acridine)(phendione)]OTf (2) and [Mn(CO)3(di-triazole)Br] (4) has been evaluated by MTS against three tumor cell lines A2780 (ovarian carcinoma), HCT116 (colorectal carcinoma), HCT116doxR (colorectal carcinoma resistant to doxorubicin), and in human dermal fibroblasts. The antiproliferative assay showed a dose-dependent effect higher in complex 1 and 2 with a selectivity toward ovarian carcinoma cell line 21 times higher than in human fibroblasts. Exposure of A2780 cells to IC50 concentrations of complex 1 and 2 led to an increase of reactive oxygen species that led to the activation of cell death mechanisms, namely via intrinsic apoptosis for 2 and autophagy and extrinsic apoptosis for 1. Both complexes do not target DNA or interfere with cell cycle progression but are able to potentiate cell migration and neovascularization (for 2) an indicative that their application might be directed for initial tumor stages to avoid tumor invasion and metastization and opening a new avenue for complex 2 application in regenerative medicine. Interestingly, both complexes do not show toxicity in both in vivo models (CAM and zebrafish).

In Vitro and In Vivo Biological Activity of Ruthenium 1,10-Phenanthroline-5,6-dione Arene Complexes.

Ruthenium(II) arene complexes exhibit promising chemotherapeutic properties. In this study, the effect of the counter anion in Ru(II) complexes was evaluated by analyzing the biological effect of two Ru(II) p-cymene derivatives with the 1,10-phenanthroline-5,6-dione ligand of general-formula [(η6-arene)Ru(L)Cl][X] X = CF3SO3 (JHOR10) and PF6 (JHOR11). The biological activity of JHOR10 and JHOR11 was examined in the ovarian carcinoma cell line A2780, colorectal carcinoma cell line HCT116, doxorubicin-resistant HCT116 (HCT116-Dox) and in normal human dermal fibroblasts. Both complexes JHOR10 and JHOR11 displayed an antiproliferative effect on A2780 and HCT116 cell lines, and low cytotoxicity in fibroblasts. Interestingly, JHOR11 also showed antiproliferative activity in the HCT116-Dox cancer cell line, while JHOR10 was inactive. Studies in A2780 cells showed that JHOR11 induced the production of reactive oxygen species (ROS) that trigger autophagy and cellular senescence, but no apoptosis induction. Further analysis showed that JHOR11 presented no tumorigenicity, with no effect in the cellular mobility, as evaluated by thye wound scratch assay, and no anti- or pro-angiogenic effect, as evaluated by the ex-ovo chorioallantoic membrane (CAM) assay. Importantly, JHOR11 presented no toxicity in chicken and zebrafish embryos and reduced in vivo the proliferation of HCT116 injected into zebrafish embryos. These results show that these are suitable complexes for clinical applications with improved tumor cell cytotoxicity and low toxicity, and that counter-anion alteration might be a viable clinical strategy for improving chemotherapy outcomes in multidrug-resistant (MDR) tumors.

Aggregation versus Biological Activity in Gold(I) Complexes. An Unexplored Concept.

The aggregation process of a series of mono- and dinuclear gold(I) complexes containing a 4-ethynylaniline ligand and a phosphane at the second coordination position (PR3-Au-C≡CC6H4-NH2, complexes 1-5, and (diphos)(Au-C≡CC6H4-NH2)2, complexes 6-8), whose biological activity was previously studied by us, has been carefully analyzed through absorption, emission, and NMR spectroscopy, together with dynamic light scattering and small-angle X-ray scattering. These experiments allow us to retrieve information about how the compounds enter the cells. It was observed that all compounds present aggregation in fresh solutions, before biological treatment, and thus they must be entering the cells as aggregates. Inductively coupled plasma atomic emission spectrometry measurements showed that mononuclear complexes are mainly found in the cytosolic fraction; the dinuclear complexes are mainly found in a subsequent fraction composed of nuclei and cytoskeleton. Additionally, dinuclear complex 8 affects the actin aggregation to a larger extent, suggesting a cooperative effect of dinuclear compounds.

In Vitro and In Vivo Effect of Palladacycles: Targeting A2780 Ovarian Carcinoma Cells and Modulation of Angiogenesis.

Palladacycles are versatile organometallic compounds that show potential for therapeutic use. Here are described the synthesis and characterization of mono- and dinuclear palladacycles bearing diphosphines. Their biological effect was investigated in A2780, an ovarian-derived cancer line, and in normal dermal fibroblasts. The compounds displayed selective cytotoxicity toward the A2780 cell line. Compound 3 decreased the cell viability through cell cycle retention in G0/G1, triggered apoptosis through the intrinsic pathway, and induced autophagy in A2780 cells. Compound 9 also induced cell cycle retention, apoptosis, and cellular detachment. Notably, compound 9 induced the production of intracellular reactive oxygen species (ROS). Our work demonstrated that compound 3 enters A2780 cells via active transport, which requires energy, while compound 9 enters A2780 cells mostly passively. The potential effect of palladacycles in angiogenesis was investigated for the first time in an in vivo chorioallantoic membrane model, showing that while compound 3 displayed an antiangiogenic effect crucial to fighting cancer progression, compound 9 promoted angiogenesis. These results show that palladacycles may be used in different clinical applications where pro- or antiangiogenic effects may be desirable.

Triazole-Based Half-Sandwich Ruthenium(II) Compounds: From In Vitro Antiproliferative Potential to In Vivo Toxicity Evaluation.

A new series of half-sandwich ruthenium(II) compounds [(η6-arene)Ru(L)Cl][CF3SO3] bearing 1,2,3-triazole ligands (arene = p-cymene, L = L1 (1); arene = p-cymene, L = L2 (2); arene = benzene, L = L1 (3); arene = benzene, L2 (4); L1 = 2-[1-(p-tolyl)-1H-1,2,3-triazol-4-yl]pyridine and L2 = 1,1'-di-p-tolyl-1H,1'H-4,4'-bi(1,2,3-triazole) have been synthesized and fully characterized by 1H and 13C NMR and IR spectroscopy, mass spectrometry, and elemental analysis. The molecular structures of 1, 2, and 4 have been determined by single-crystal X-ray diffraction. The cytotoxic activity of 1-4 was evaluated using the MTS assay against human tumor cells, namely ovarian carcinoma (A2780), colorectal carcinoma (HCT116), and colorectal carcinoma resistant to doxorubicin (HCT116dox), and against normal primary fibroblasts. Whereas compounds 2 and 4 showed no cytotoxic activity toward tumor cell lines, compounds 1 and 3 were active in A2780, while showing no antiproliferative effect in human normal dermal fibroblasts at the IC50 concentrations of the A2780 cell line. Exposure of ovarian carcinoma cells to IC50 concentrations of compound 1 or 3 led to an accumulation of reactive oxygen species and an increase of apoptotic and autophagic cells. While compound 3 displayed low levels of angiogenesis induction, compound 1 showed an ability to induce cell cycle delay and to interfere with cell migration. When the in vivo toxicity studies using zebrafish and chicken embryos are considered, compounds 1 and 3, which were not lethal, are promising candidates as anticancer agents against ovarian cancer due to their good cytotoxic activity in tumor cells and their low toxicity both in vitro and in vivo.

Half-Sandwich Ru(p-cymene) Compounds with Diphosphanes: In Vitro and In Vivo Evaluation As Potential Anticancer Metallodrugs.

Ruthenium(II) complexes are currently considered attractive alternatives to the widely used platinum-based drugs. We present herein the synthesis and characterization of half-sandwich ruthenium compounds formulated as [Ru(p-cymene)(L)Cl][CF3SO3] (L = 1,1-bis(methylenediphenylphosphano)ethylene, 1; L = 1,1-bis(diphenylphosphano)ethylene, 2), which were characterized by elemental analysis, mass spectrometry, 1H and 31P{1H} NMR, UV-vis and IR spectroscopy, conductivity measurements and cyclic voltammetry. The molecular structures for both complexes were determined by single-crystal X-ray diffraction. Their cytotoxic activity was evaluated using the MTT assay against human tumor cells, namely ovarian (A2780) and breast (MCF7 and MDA-MB-231). Both complexes were active against breast adenocarcinoma cells, with complex 1 exhibiting a quite remarkable cytotoxicity in the submicromolar range. Interestingly, at concentrations equivalent to the IC50 values in the MCF7 cancer cells, complexes 1 and 2 presented lower cytotoxicity in normal human primary fibroblasts. The antiproliferative effects of 1 and 2 in MCF7 cells might be associated with the induction of reactive oxygen species (ROS), leading to a combined cell death mechanism via apoptosis and autophagy. Despite the fact that in vitro a partial intercalation between complexes and DNA was observed, no MCF7 cell cycle delay or arrest was observed, indicating that DNA might not be a direct target. Complexes 1 and 2 both exhibited a moderate to strong interaction with human serum albumin, suggesting that protein targets may be involved in their mode of action. Their acute toxicity was evaluated in the zebrafish model. Complex 1 (the most toxic of the two) exhibited a lethal toxicity LC50 value about 1 order of magnitude higher than any IC50 concentrations found for the cancer cell models used, highlighting its therapeutic relevance as a drug candidate in cancer chemotherapy.

Exploiting the antiproliferative potential of spiropyrazoline oxindoles in a human ovarian cancer cell line.

Cancer is still one of the deadliest diseases worldwide despite the efforts in its early detection and treatment strategies. However, most chemotherapeutic agents still present side effects in normal tissues and acquired resistance that limit their efficacy. Spiropyrazoline oxindoles might be good alternatives as they have shown antiproliferative activity in human breast and colon cancer cell lines, without eliciting cytotoxicity in healthy cells. However, their potential for ovarian cancer was never tested. In this work, the antiproliferative activity of five spiropyrazoline oxindoles was assessed in ovarian cancer cells A2780 and the biological targets and mechanism of action of the most promising compound evaluated. Compound 1a showed the highest antiproliferative effect, as well as the highest selectivity for A2780 cells compared to healthy fibroblasts. This antiproliferative effect results from the induction of cell death by mitochondria-mediated apoptosis and autophagy. In vitro DNA interaction studies demonstrated that 1a interacts with DNA by groove-binding, without triggering genotoxicity. In addition, 1a showed a strong affinity to bovine serum albumin that might be important for further inclusion in drug delivery platforms. Proteomic studies reinforced 1a role in promoting A2780 endoplasmatic reticulum (ER) stress by destabilizing the correct protein folding which triggers cell death via apoptosis and autophagy.

Genetic Biomarkers in Chronic Myeloid Leukemia: What Have We Learned So Far?

Chronic Myeloid Leukemia (CML) is a rare malignant proliferative disease of the hematopoietic system, whose molecular hallmark is the Philadelphia chromosome (Ph). The Ph chromosome originates an aberrant fusion gene with abnormal kinase activity, leading to the buildup of reactive oxygen species and genetic instability of relevance in disease progression. Several genetic abnormalities have been correlated with CML in the blast phase, including chromosomal aberrations and common altered genes. Some of these genes are involved in the regulation of cell apoptosis and proliferation, such as the epidermal growth factor receptor (EGFR), tumor protein p53 (TP53), or Schmidt-Ruppin A-2 proto-oncogene (SRC); cell adhesion, e.g., catenin beta 1 (CTNNB1); or genes associated to TGF-ß, such as SKI like proto-oncogene (SKIL), transforming growth factor beta 1 (TGFB1) or transforming growth factor beta 2 (TGFB2); and TNF-α pathways, such as Tumor necrosis factor (TNFA) or Nuclear factor kappa B subunit 1 (NFKB1). The involvement of miRNAs in CML is also gaining momentum, where dysregulation of some critical miRNAs, such as miRNA-451 and miRNA-21, which have been associated to the molecular modulation of pathogenesis, progression of disease states, and response to therapeutics. In this review, the most relevant genomic alterations found in CML will be addressed.

Evaluation of the In Vitro and In Vivo Efficacy of Ruthenium Polypyridyl Compounds against Breast Cancer.

The clinical success of cisplatin, carboplatin, and oxaliplatin has sparked the interest of medicinal inorganic chemistry to synthesize and study compounds with non-platinum metal centers. Despite Ru(II)-polypyridyl complexes being widely studied and well established for their antitumor properties, there are not enough in vivo studies to establish the potentiality of this type of compound. Therefore, we report to the best of our knowledge the first in vivo study of Ru(II)-polypyridyl complexes against breast cancer with promising results. In order to conduct our study, we used MCF7 zebrafish xenografts and ruthenium complexes [Ru(bipy)2(C12H8N6-N,N)][CF3SO3]2Ru1 and [{Ru(bipy)2}2(µ-C12H8N6-N,N)][CF3SO3]4Ru2, which were recently developed by our group. Ru1 and Ru2 reduced the tumor size by an average of 30% without causing significant signs of lethality when administered at low doses of 1.25 mg·L-1. Moreover, the in vitro selectivity results were confirmed in vivo against MCF7 breast cancer cells. Surprisingly, this work suggests that both the mono- and the dinuclear Ru(II)-polypyridyl compounds have in vivo potential against breast cancer, since there were no significant differences between both treatments, highlighting Ru1 and Ru2 as promising chemotherapy agents in breast cancer therapy.

Synthesis of new hetero-arylidene-9(10H)-anthrone derivatives and their biological evaluation.

New hetero-arylidene-9(10H)-anthrone derivatives (1) were synthesized from reaction of 1,2-dimethyl-3-alkyl imidazolium salts (2) and 9-anthracenecarboxaldehyde. Ion exchange of the anion with dioctyl sulfosuccinate and lithium bis(trifluoromethanesulfonyl)imide led to the preparation of other derivatives. The antiproliferative effect of the compounds was evaluated in human ovarian (A2780) and colorectal (HCT116) carcinoma cell lines and in normal primary human fibroblasts. Compound 1 presented an antiproliferative effect related to the imidazolium pattern of substitution with compounds having a decyl group at the R-position (1c and 3c) showing the highest cytotoxic activities in all cell lines independently of the counter ion. Compounds 1b and 1c internalize A2780 cancer cells via a passive or an active transport, respectively, inducing A2780 cell death via an extrinsic apoptosis (1b) or intrinsic apoptosis and oncosis (1c). The localization of both compounds in the cytoplasm coupled to the absence of reactive oxygen species (ROS) induction suggest that the mechanisms of toxicity might be different than those of other anthracyclines currently used in chemotherapy.

Hyperthermia Induced by Gold Nanoparticles and Visible Light Photothermy Combined with Chemotherapy to Tackle Doxorubicin Sensitive and Resistant Colorectal Tumor 3D Spheroids.

Current cancer therapies are frequently ineffective and associated with severe side effects and with acquired cancer drug resistance. The development of effective therapies has been hampered by poor correlations between pre-clinical and clinical outcomes. Cancer cell-derived spheroids are three-dimensional (3D) structures that mimic layers of tumors in terms of oxygen and nutrient and drug resistance gradients. Gold nanoparticles (AuNP) are promising therapeutic agents which permit diminishing the emergence of secondary effects and increase therapeutic efficacy. In this work, 3D spheroids of Doxorubicin (Dox)-sensitive and -resistant colorectal carcinoma cell lines (HCT116 and HCT116-DoxR, respectively) were used to infer the potential of the combination of chemotherapy and Au-nanoparticle photothermy in the visible (green laser of 532 nm) to tackle drug resistance in cancer cells. Cell viability analysis of 3D tumor spheroids suggested that AuNPs induce cell death in the deeper layers of spheroids, further potentiated by laser irradiation. The penetration of Dox and earlier spheroid disaggregation is potentiated in combinatorial therapy with Dox, AuNP functionalized with polyethylene glycol (AuNP@PEG) and irradiation. The time point of Dox administration and irradiation showed to be important for spheroids destabilization. In HCT116-sensitive spheroids, pre-irradiation induced earlier disintegration of the 3D structure, while in HCT116 Dox-resistant spheroids, the loss of spheroid stability occurred almost instantly in post-irradiated spheroids, even with lower Dox concentrations. These results point towards the application of new strategies for cancer therapeutics, reducing side effects and resistance acquisition.

Biofilm development and computational screening for new putative inhibitors of a homolog of the regulatory protein BrpA in Streptococcus dysgalactiae subsp. dysgalactiae.

Streptococcus dysgalactiae subsp. dysgalactiae (SDSD), a Lancefield group C streptococci (GCS), is a frequent cause of bovine mastitis. This highly prevalent disease is the costliest in dairy industry. Adherence and biofilm production are important factors in streptoccocal pathogenesis. We have previously described the adhesion and internalization of SDSD isolates in human cells and now we describe the biofilm production capability of this bacterium. In this work we integrated microbiology, imaging and computational methods to evaluate the biofilm production capability of SDSD isolates; to assess the presence of biofilm regulatory protein BrpA homolog in the biofilm producers; and to predict a structural model of BrpA-like protein and its binding to putative inhibitors. Our results show that SDSD isolates form biofilms on abiotic surface such as glass (hydrophilic) and polystyrene (hydrophobic), with the strongest biofilm formation observed in glass. This ability was mainly associated with a proteinaceous extracellular matrix, confirmed by the dispersion of the biofilms after proteinase K and trypsin treatment. The biofilm formation in SDSD isolates was also confirmed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Under SEM observation, VSD16 isolate formed cell aggregates during biofilm growth while VSD9 and VSD10 formed smooth and filmy layers. We show that brpA-like gene is present and expressed in SDSD biofilm-producing isolates and its expression levels correlated with the biofilm production capability, being more expressed in the late exponential phase of planktonic growth compared to biofilm growth. Fisetin, a known biofilm inhibitor and a putative BrpA binding molecule, dramatically inhibited biofilm formation by the SDSD isolates but did not affect planktonic growth, at the tested concentrations. Homology modeling was used to predict the 3D structure of BrpA-like protein. Using high throughput virtual screening and molecular docking, we selected five ligand molecules with strong binding affinity to the hydrophobic cleft of the protein, making them potential inhibitor candidates of the SDSD BrpA-like protein. These results warrant further investigations for developing novel strategies for SDSD anti-biofilm therapy.

Targeting Tumor Microenvironment for Cancer Therapy.

Cancer development is highly associated to the physiological state of the tumor microenvironment (TME). Despite the existing heterogeneity of tumors from the same or from different anatomical locations, common features can be found in the TME maturation of epithelial-derived tumors. Genetic alterations in tumor cells result in hyperplasia, uncontrolled growth, resistance to apoptosis, and metabolic shift towards anaerobic glycolysis (Warburg effect). These events create hypoxia, oxidative stress and acidosis within the TME triggering an adjustment of the extracellular matrix (ECM), a response from neighbor stromal cells (e.g., fibroblasts) and immune cells (lymphocytes and macrophages), inducing angiogenesis and, ultimately, resulting in metastasis. Exosomes secreted by TME cells are central players in all these events. The TME profile is preponderant on prognosis and impacts efficacy of anti-cancer therapies. Hence, a big effort has been made to develop new therapeutic strategies towards a more efficient targeting of TME. These efforts focus on: (i) therapeutic strategies targeting TME components, extending from conventional therapeutics, to combined therapies and nanomedicines; and (ii) the development of models that accurately resemble the TME for bench investigations, including tumor-tissue explants, "tumor on a chip" or multicellular tumor-spheroids.

The Important Role of the Nuclearity, Rigidity, and Solubility of Phosphane Ligands in the Biological Activity of Gold(I) Complexes.

A series of 4-ethynylaniline gold(I) complexes containing monophosphane (1,3,5-triaza-7-phosphaadamantane (pta; 2), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (3), and PR3 , with R=naphthyl (4), phenyl (5), and ethyl (6)) and diphosphane (bis(diphenylphosphino)acetylene (dppa; 7), trans-1,2-bis(diphenylphosphino)ethene (dppet; 8), 1,2-bis(diphenylphosphino)ethane (dppe; 9), and 1,3-bis(diphenylphosphino)propane (dppp; 10)) ligands have been synthesized and their efficiency against tumor cells evaluated. The cytotoxicity of complexes 2-10 was evaluated in human colorectal (HCT116) and ovarian (A2780) carcinoma as well as in normal human fibroblasts. All the complexes showed a higher antiproliferative effect in A2780 cells, with the cytotoxicity decreasing in the following order 5>6=9=10>8>2>4>7>3. Complex 4 stands out for its very high selectivity towards ovarian carcinoma cells (IC50 =2.3 µm) compared with colorectal carcinoma and normal human fibroblasts (IC50 >100 µm), which makes this complex very attractive for ovarian cancer therapy. Its cytotoxicity in these cells correlates with the induction of the apoptotic process and an increase of intracellular reactive oxygen species (ROS). The effects of the nuclearity, rigidity, and solubility of these complexes on their biological activity were also analyzed. X-ray crystal structure determination allowed the identification of short N-H⋅⋅⋅π contacts as the main driving forces for the three-dimensional packing in these molecules.

Understanding the response of Desulfovibrio desulfuricans ATCC 27774 to the electron acceptors nitrate and sulfate - biosynthetic costs modulate substrate selection.

Sulfate-reducing bacteria (SRB) are a diverse group of anaerobic microorganisms that obtain their energy from dissimilatory sulfate reduction. Some SRB species have high respiratory versatility due to the possible use of alternative electron acceptors. A good example is Desulfovibrio desulfuricans ATCC 27774, which grows in the presence of nitrate (end product: ammonium) with higher rates and yields to those observed in sulfate containing medium (end product: sulfide). In this work, the mechanisms supporting the respiratory versatility of D. desulfuricans were unraveled through the analysis of the proteome of the bacterium under different experimental conditions. The most remarkable difference in the two-dimensional gel electrophoresis maps is the high number of spots exclusively represented in the nitrate medium. Most of the proteins with increase abundance are involved in the energy metabolism and the biosynthesis of amino acids (or proteins), especially those participating in ammonium assimilation processes. qPCR analysis performed during different stages of the bacterium's growth showed that the genes involved in nitrate and nitrite reduction (napA and nrfA, respectively) have different expressions profiles: while napA did not vary significantly, nrfA was highly expressed at a 6h time point. Nitrite levels measured along the growth curve revealed a peak at 3h. Thus, the initial consumption of nitrate and concomitant production of nitrite must induce nrfA expression. The activation of alternative mechanisms for energy production, aside several N-assimilation metabolisms and detoxification processes, solves potential survival problems in adapting to different environments and contributes to higher bacterial growth rates.

Dinuclear RuII(bipy)2 Derivatives: Structural, Biological, and in Vivo Zebrafish Toxicity Evaluation.

Ruthenium-based drugs exhibit interesting properties as potential anticancer pharmaceuticals. We herein present the synthesis and characterization of a new family of ruthenium complexes with formulas [{Ru(bipy)2}2(µ-L)][CF3SO3]4 (L = bptz, 1a) and [{Ru(bipy)2}2(µ-L)][CF3SO3]2 (L = arphos, 2a; dppb, 3a; dppf, 4a), which were synthesized from the Ru(II) precursor compound cis-Ru(bipy)2Cl2. The complexes were characterized by elemental analysis, mass spectrometry, 1H and 31P{1H} NMR, IR spectroscopy, and conductivity measurements. The molecular structures for three Ru(II) compounds were determined by single-crystal X-ray diffraction. The newly developed compounds interact with CT-DNA by intercalation, in particular, 2a, 3a, and 4a, which also seemed to induce some extent of DNA degradation. This effect seemed to be related with the formation of reactive oxygen species. The cytotoxic activity was evaluated against A2780, MCF7, and MDAMB231 human tumor cells. Compounds 2a and 4a were the most cytotoxic with activity compared to cisplatin (∼2 µM, 72 h) in the A2780 cisplatin sensitive cells. All the compounds induced A2780 cell death by apoptosis, however, to a lesser extent for compounds 4a and 2a. For these compounds, the mechanism of cell death in addition to apoptosis seemed to involve autophagy. In vivo toxicity was evaluated using the zebrafish embryo model. LC50 estimates varied from 5.397 (3a) to 39.404 (1a) mg/L. Considering the in vivo toxicity in zebrafish embryos and the in vitro cytotoxicity in cancer cells, compound 1a seems to be the safest having no effect on dechirionation and presenting a good antiproliferative activity against ovarian carcinoma cells.

Smuggling gold nanoparticles across cell types - A new role for exosomes in gene silencing.

Once released to the extracellular space, exosomes enable the transfer of proteins, lipids and RNA between different cells, being able to modulate the recipient cells' phenotypes. Members of the Rab small GTP-binding protein family, such as RAB27A, are responsible for the coordination of several steps in vesicle trafficking, including budding, mobility, docking and fusion. The use of gold nanoparticles (AuNPs) for gene silencing is considered a cutting-edge technology. Here, AuNPs were functionalized with thiolated oligonucleotides anti-RAB27A (AuNP@PEG@anti-RAB27A) for selective silencing of the gene with a consequent decrease of exosomes´ release by MCF-7 and MDA-MB-453 cells. Furthermore, communication between tumor and normal cells was observed both in terms of alterations in c-Myc gene expression and transportation of the AuNPs, mediating gene silencing in secondary cells.

Tumor Microenvironment Modulation via Gold Nanoparticles Targeting Malicious Exosomes: Implications for Cancer Diagnostics and Therapy.

Exosomes are nanovesicles formed in the endosomal pathway with an important role in paracrine and autocrine cell communication. Exosomes secreted by cancer cells, malicious exosomes, have important roles in tumor microenvironment maturation and cancer progression. The knowledge of the role of exosomes in tumorigenesis prompted a new era in cancer diagnostics and therapy, taking advantage of the use of circulating exosomes as tumor biomarkers due to their stability in body fluids and targeting malignant exosomes' release and/or uptake to inhibit or delay tumor development. In recent years, nanotechnology has paved the way for the development of a plethora of new diagnostic and therapeutic platforms, fostering theranostics. The unique physical and chemical properties of gold nanoparticles (AuNPs) make them suitable vehicles to pursuit this goal. AuNPs' properties such as ease of synthesis with the desired shape and size, high surface:volume ratio, and the possibility of engineering their surface as desired, potentiate AuNPs' role in nanotheranostics, allowing the use of the same formulation for exosome detection and restraining the effect of malicious exosomes in cancer progression.

Characterization of antiproliferative potential and biological targets of a copper compound containing 4'-phenyl terpyridine.

Several copper complexes have been assessed as anti-tumor agents against cancer cells. In this work, a copper compound [Cu(H2O){OS(CH3)2}L](NO3)2 incorporating the ligand 4'-phenyl-terpyridine antiproliferative activity against human colorectal, hepatocellular carcinomas and breast adenocarcinoma cell lines was determined, demonstrating high cytotoxicity. The compound is able to induce apoptosis and a slight delay in cancer cell cycle progression, probably by its interaction with DNA and induction of double-strand pDNA cleavage, which is enhanced by oxidative mechanisms. Moreover, proteomic studies indicate that the compound induces alterations in proteins involved in cytoskeleton maintenance, cell cycle progression and apoptosis, corroborating its antiproliferative potential.