Amorphous silica nanoparticles exhibit antitumor activity in triple-negative breast cancer cells.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is mainly treated with cytotoxic chemotherapy. However, this treatment is not always effective, and an important percentage of patients develop recurrence. Nanomaterials are emerging as alternative treatment options for various diseases, including cancer. This work reports the synthesis, characterization, antitumor activity evaluation, and sub-acute toxicity studies of two formulations based on amorphous silica nanoparticles (SiNPs). They are functionalized with 3-aminopropyltriethoxisilane (Si@NH2) and folic acid (FA; Si@FA). The results show that SiNPs reduce the viability and migration of TNBC MDA-MB-231 and 4T1 cell lines and Si@FA do not affect the growth of the mammary nonmalignant HC11 cells. In addition, Si@FA induces reactive oxygen species (ROS) generation and displays antiproliferative and subsequently proapoptotic effects in MDA-MB-231 cells. Moreover, none of the SiNPs cause signs of sub-acute toxicity in mice when administered at 30 mg/kg over a month. In conclusion, these nanosystems display intrinsic antitumor activity without causing toxic in vivo effects, being a promising therapeutic alternative for TNBC.

5-Nitrofuryl-Containing Thiosemicarbazone Gold(I) Compounds: Synthesis, Stability Studies, and Anticancer Activity.

This work describes the synthesis of four gold(I) [AuClL] compounds containing chloro and biologically active protonated thiosemicarbazones based on 5-nitrofuryl (L=HSTC). The stability of the compounds in dichloromethane, DMSO, and DMSO/culture media solutions was investigated by spectroscopy, cyclic voltammetry, and conductimetry, indicating the formation overtime of cationic monometallic [Au(HTSC)(DMSO)]± or [Au(HTSC)2 ]± , and/or dimeric species. Neutral [{Au(TSC)}2 ] species were obtained from one of the compounds in dichlomethane/n-hexane solution and characterized by X-ray crystallography revealing a Au-Au bond, and deprotonated thiosemicarbazone (TSC). The cytotoxicity of the gold compounds and thiosemicarbazone ligands was evaluated against selected cancer cell lines and compared to that of Auranofin. Studies of the most stable, cytotoxic, and selective compound on a renal cancer cell line (Caki-1) demonstrated its relevant antimigratory and anti-angiogenic properties, and preferential accumulation in the cell nuclei. Its mode of action seems to involve interaction with DNA, and subsequent cell death via apoptosis.

Quercetin-Rich Extracts from Onions (Allium cepa) Play Potent Cytotoxicity on Adrenocortical Carcinoma Cell Lines, and Quercetin Induces Important Anticancer Properties.

Adrenocortical carcinoma (ACC) is a rare subtype of cancer, with a poor prognosis in children and adults. Mitotane is the only approved adrenolytic drug for the treatment of ACC, which has controversies regarding its efficacy and side effects on patients. Onion (Allium cepa), a worldwide consumed food, is associated with many health benefits. Along with its glycosides, the flavonoid quercetin is abundant in onions. After evaluating the cytotoxicity of A. cepa extracts on adrenocortical carcinoma cell line (H295R), the rich quercetin fractions had better results. Then, we aimed to compare the quercetin vs. mitotane effectiveness, using adrenocortical carcinoma cell lines H295R and SW-13. Quercetin showed a higher cytotoxicity response on both cancerous cell lines after 10 µM concentration, while mitotane only after 30 µM. Cell cycle dynamics were altered upon quercetin treatments, with G2 phase increase with 30 µM of quercetin on H295R cell line and G1 arrest on SW-13 cell line with 15 µM. Early and late apoptosis, alongside intracellular calcium, were increased on SW-13 treated with 30 µM of quercetin, and ROS rates were reduced by quercetin on H295R. Therefore, quercetin-rich onions have the potential to be a natural source of anticancer agents for adrenocortical carcinoma.

Phenoxy- and Phenylamino-Heterocyclic Quinones: Synthesis and Preliminary Anti-Pancreatic Cancer Activity.

The successful application of fragment-based drug discovery strategy for the efficient synthesis of phenoxy- or phenylamino-2-phenyl-benzofuran, -benzoxazole and -benzothiazole quinones is described. Interestingly, in the final step of the synthesis of the target compounds, unusual results were observed on the regiochemistry of the reaction of bromoquinones with phenol and aniline. A theoretical study was carried out for better understanding the factors that control the regiochemistry of these reactions. The substituted heterocyclic quinones were evaluated in vitro to determine their cytotoxicity by the MTT method in three pancreatic cancer cell lines (MIA-PaCa-2, BxPC-3, and AsPC-1). Phenoxy benzothiazole quinone 26a showed potent cytotoxic activity against BxPC-3 cell lines, while phenylamino benzoxazole quinone 20 was the most potent on MIA-PaCa-2 cells. Finally, electrochemical properties of these quinones were determined to correlate with a potential mechanism of action. All these results, indicate that the phenoxy quinone fragment led to compounds with increased activity against pancreatic cancer cells.

In vitro Biological Tests as the First Tools To Validate Magnetic Nanotheranostics for Colorectal Cancer Models.

Colorectal cancer (CRC) remains a leading cause of cancer death. Nanotechnology has focused on reaching more effective treatments. In this concern, magnetic nanoparticles (MNPs) have been studied for a wide range of biomedical applications related to CRC, such as diagnostic imaging, drug delivery and thermal therapy. However, limited research is currently found in the open literature that refers to nanosystems combining all these mentioned areas (theranostics). When developing nanosystems intended as theranostics applied to CRC, possible variations between patients must be considered. Therefore, multiple in vitro assays are required as guidance for future preclinical and clinical trials. The objective of this contribution is to evaluate the available and recent literature regarding the interactions of MNP and CRC models, aiming to critically analyze the information given by the commonly used assays and evaluate the data provided by each one with a view to implementing this novel technology in CRC diagnostics and therapy.

Isoxazole-Derived Aroylhydrazones and Their Dinuclear Copper(II) Complexes Show Antiproliferative Activity on Breast Cancer Cells with a Potentially Alternative Mechanism Of Action.

This paper reports the design, synthesis and cytotoxicity studies of two new isoxazole-derived aroylhydrazone ligands and their dinuclear copper(II) complexes. Compounds were fully characterized by various spectroscopic and analytical techniques. The molecular structures of four derivatives were confirmed by X-ray crystallography. The stability of the ligands and the complexes in aqueous medium was monitored spectroscopically. Both the ligands and the complexes were shown to interact with calf thymus DNA (ct-DNA). Additionally, structures containing a phenol pendant arm were significantly more cytotoxic than those carrying a pendant pyridine substituent, reaching sub-micromolar IC50 values on the triple-negative human breast cancer cell line MDA-MB-231. The metal chelation and transchelation ability of the compounds towards FeII , FeIII and ZnII ions was explored as a possible mechanism of action of these compounds.

Antitumoral Potential of Lansbermin-I, a Novel Disintegrin from Porthidium lansbergii lansbergii Venom on Breast Cancer Cells.

BACKGROUND: Disintegrins from snake venoms bind with high specificity cell surface integrins, which are important pharmacological targets associated with cancer development and progression. OBJECTIVE: In this study, we isolated a disintegrin from the Porthidium lansbergii lansbergii venom and evaluated its antitumoral effects on breast cancer cells. METHODS: The isolation of the disintegrin was performed on RP-HPLC and the inhibition of platelet aggregation was evaluated on human platelet-rich plasma. The inhibition of cell adhesion was also evaluated in vitro on cultures of cell lines by the MTT method as well as the inhibition of breast cancer cell migration by the wound healing assay. The binding of the disintegrin to integrin subunits was verified by flow cytometry and confocal microscopy. Finally, inhibition of angiogenesis was assessed in vitro on HUVEC cells and the concentration of VEGF was measured in the cellular supernatants. RESULTS: The disintegrin, named Lansbermin-I, is a low molecular weight protein (< 10 kDa) that includes an RGD on its sequence identified previously. Lansbermin-I showed potent inhibition of ADP and collagen-induced platelet aggregation on human plasma and also displayed inhibitory effects on the adhesion and migration of breast cancer MCF7 and MDA-MB 231cell lines, without affecting nontumorigenic breast MCF-10A and lung BEAS cells. Additionally, Lansbermin-I prevented MCF7 cells to adhere to fibronectin and collagen, and also inhibited in vitro angiogenesis on human endothelial HUVEC cells. CONCLUSION: Our results display the first report on the antitumor and anti-metastatic effects of an RGDdisintegrin isolated from a Porthidium snake venom by possibly interfering with α2 and/or ß1-containing integrins. Thus, Lansbermin-I could be an attractive model to elucidate the role of disintegrins against breast cancer development.

Antiproliferative Effect of Urera baccifera Leaves Against Ovarian Carcinoma Cell Line (OVCAR-3)

Abstract Natural products, especially phytochemicals, have been extensively studies and have exhibited important antiproliferative effects. The American native species Urera baccifera (L.) Gaudich. ex Wedd. (Urticaceae) is widely distributed in Brazil, where it is known as urtiga-vermelha or urtigão. The leaves are popularly used as anti-inflammatory, antirheumatic and in the treatment of gastric disorders. However, the antiproliferative potential of this plant against human tumor cells remain to be elucidated. In this study, we evaluated the antiproliferative effects of U. baccifera leaves extracts and fractions against a panel of human tumor cell lines in vitro besides a chemical evaluation of the most active sample by mass spectrometry (ESI-IT-MSn). The hydroalcoholic extract was inactive while dichloromethane extract showed moderate cytostatic activity against ovarian carcinoma cell line (OVCAR-3, GI50 = 1.5 μg/mL). More, the ethyl acetate and n-butanol fractions did not show important activity against tumour cell while the dichloromethane and hexane fractions showed moderate cytostatic activity against ovarian tumor cell line (OVCAR-3, GI50 = 12.7 and 9.4 μg/mL, respectively). Finally, the chemical profile evaluated by mass spectrometry (ESI-IT-MSn) allowed the detection of flavonoids in the HEU and hydroxylated fatty acid in DEU that can explain partially the biological effects observed. This is the first report of the antiproliferative effects of U. baccifera, and DEU has shown potential as a promising source of bioactive compounds.

Anticancer Properties of Essential Oils: An Overview.

BACKGROUND: Essential oils are complex mixtures of low molecular weight compounds extracted from plants. Their main constituents are terpenes and phenylpropanoids, which are responsible for their biological and pharmaceutical properties, such as insecticidal, parasiticidal, antimicrobial, antioxidant, anti-inflammatory, analgesic, antinociceptive, anticarcinogenic, and antitumor properties. Cancer is a complex genetic disease considered as a serious public health problem worldwide, accounting for more than 8 million deaths annually. OBJECTIVE: The activities of prevention and treatment of different types of cancer and the medicinal potential of essential oils are addressed in this review. CONCLUSION: Several studies have demonstrated anti-carcinogenic and antitumor activity for many essential oils obtained from various plant species. They may be used as a substitution to or in addition to conventional anti-cancer therapy. Although many studies report possible mechanisms of action for essential oils compounds, more studies are necessary in order to apply them safely and appropriately in cancer therapy.

Antiproliferative effects of pinostrobin and 5,6-dehydrokavain isolated from leaves of Alpinia zerumbet

Abstract Natural products are a major source of drugs for the treatment of cancer. The species Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm, Zingiberaceae, is widely distributed in Brazil where it is known as "colônia". The leaves are commonly used in the treatment of hypertension and dyspepsia, however, the effects of A. zerumbet extracts and isolated substances on human cancer cells remain to be elucidated. This study was designed to identify the chemical constituents of hydroalcoholic and dichloromethane extracts from A. zerumbet leaves and to investigate their in vitro antiproliferative activity. The isolated phytochemicals included kaempferol, dihydro-5,6-dehydrokavain, 5,6-dehydrokavain, and pinostrobin. The hydroalcoholic extract inhibited cellular proliferation only at high concentrations, while the dichloromethane extract showed a moderate antiproliferative effect against leukemia and lung tumor cell lines. 5,6-Dehydrokavain showed potent cytostatic activity against glioblastoma cells and a moderate effect on all other tumor cell lines. Pinostrobin showed potent activity against leukemia and breast tumor cell lines and moderate cytostatic effect against ovarian cell. Furthermore, this is the first report on the isolation of kaempferol and pinostrobin from A. zerumbet leaves. Moreover, the purification process described in this study was effective. These results suggest that A. zerumbet leaves are a promising source of anticancer compounds.

Heteroleptic oxidovanadium(IV) complexes of 2-hydroxynaphtylaldimine and polypyridyl ligands against Trypanosoma cruzi and prostate cancer cells.

In Latin America Chagas disease is an endemic illness caused by the parasite Trypanosoma cruzi (T. cruzi), killing more people than any other parasitic disease. Current chemotherapies are old and inadequate, thus the development of efficient ones is urgently needed. Vanadium-based complexes have been shown to be a promising approach both against parasitic diseases and cancer and this study aims to achieve significant advances in the pursue of effective compounds. Heteroleptic vanadium complexes of Schiff bases and polypyridine compounds were prepared and their stability in solution evaluated by EPR (Electronic Paramagnetic Resonance) and NMR spectroscopy. Their in vitro activities were evaluated against T. cruzi and a set of cells lines representative of human cancer conditions, namely ovarian, breast and prostate cancer. In T. cruzi, most of the complexes depicted IC50 values in the low µM range, induced changes of mitochondrial membrane potential and apoptosis. In cancer cells, complexes showed good to moderate activity and in metastatic cells (prostate PC3), some complexes inhibited the migratory ability, this suggesting that they display antimetastatic potential. Interestingly, complex 5 seemed to have a dual effect being the most cytotoxic complex on all cancer cells and also the most active anti-T-cruzi compound of the series. Globally the complexes showed promising anticancer and anti T. cruzi activities and also displayed some characteristics indicating they are worth to be further explored as antimetastatic drugs.

Experimental and theoretical studies of copper complexes with isomeric dipeptides as novel candidates against breast cancer.

In the search for new cytotoxic drugs, two copper complexes with isomeric dipeptides (Ala-Phe and Phe-Ala) were developed in order to determine the influence of their different structures in the modulation of the chemical, biochemical and biological properties. Spectroscopic, voltammetric and equilibrium studies were performed providing information about the chemical properties. The superoxide dismutase (SOD) activity was studied and showed differences of IC50 for both Cu-Ala-Phe (IC50=4.5) and Cu-Phe-Ala (IC50=45). The computational results permitted to explain this behavior proposing that it is feasible that the O2- anion is attracted straight to the positive zone in Cu-Ala-Phe whereas for Cu-Phe-Ala this phenomenon would happen to a smaller extent. Confirming our previous studies, both complexes interacted with DNA. Molecular docking studies showed that the position of the phenyl ring modulates the complex-DNA affinity and in Cu-Ala-Phe the docked conformation allows the copper ion to face the DNA basis, giving rise to a more stable complex-DNA adduct than for Cu-Phe-Ala. In spite of the fact that Atomic Force Microscopy showed plasmid compactation and aggregation for both complexes, the image showed softer changes in the case of Cu-Ala-Phe in comparison with those produced by Cu-Phe-Ala. In order to evaluate the effect of Cu-Ala-Phe and Cu-Phe-Ala complexes against tumor cells, we have employed three aggressive metastatic breast adenocarcinoma cellular models, derived from human (MDA-MB-231 and MCF-7) and mouse (4T1) spontaneous tumors. These experiments showed that both Cu-dipeptide complexes have a similar cytotoxic effect against breast cancer cells, and lower toxicity against BJ non-tumor cells in comparison to Cisplatin.

Alkylphosphocholines as Promising Antitumor Agents: Exploring the Role of Structural Features on the Hemolytic Potential.

Alkylphosphocholines (APC) are promising antitumor agents, which have the cellular membrane as primary target; however, red blood cell damage limits their wide therapeutic use. A variety of APC analogs has been synthesized and tested showing less hemolytic effect than the class prototype, Miltefosine (HePC). In this work, chemometric methods were applied to a set of 34 APC derivatives to identify the most relevant structural and molecular features of hemolytic activity. The APC derivatives were divided into three groups: (i) N-methylpiperidine and N-methylmorpholine derivatives with a long alkyl chain or flexible cyclopentadecyl rings, displaying a hemolytic rate of 17 %; (ii) adamantyl and cyclopentadecyl derivatives, showing an average hemolysis of 39 %; and, N,N,N-trimethylammonium, trans-N,N,N-trimethylcyclohexanamine, and trans-N,N,N-trimethylcyclopentanamine derivatives, whose average hemolysis was 41 %. The findings suggested that the presence of either bulky cationic head groups, or rings such as adamantyl and cyclohexyl, primarily increases the hemolysis of compounds with eleven atoms in the alkyl chain. Moreover, the macrocyclic cyclopentadecyl seems to be important to the hemolytic potential especially of compounds with five carbon atoms in the alkyl chain. Regarding linear carbon chain derivatives with no ring substitution, less bulky cationic head groups seem to favor hemolysis. Thus, in order to design more potent and less toxic APC antitumors, the reported structural/molecular patterns should not be included in their structure.

Predicting Novel Antitumor Agents: 3D-Pharmacophore Mapping of ß-N-biaryl Ether Sulfonamide-Based Hydroxamates as Potentially MMP-2 Inhibitors.

Matrix metalloproteinases (MMP) are a group of enzymes related to extracelular matrix remodeling. Some types of MMP are overexpressed by malignant tumors, mainly the MMP-2 subtype, and have been associated to cancer invasiveness and metastasis. A receptor-independent (RI) 4D-QSAR formalism was applied, herein, to a set of forty ß-N-biaryl ether sulfonamide hydroxamates, previously reported as potent MMP-2 inhibitors, in order to map 3D-pharmacophore models and predict novel antitumor agents. The best RI 4D-QSAR model was statistically significant (N=30, r(2) =0.93, q(2) =0.88, five occupancy descriptors (GCOD), LSE=0.04, LOF=0.11, outliers=0), robust and not obtained by chance. The external predictability was 75 % (test set; N=8). A different orientation (binding mode) in the MMP-2 catalytic site was suggested regarding the most hydrophobic portion (R1 ) of the compounds' structure. Compounds were predicted and their inhibitory activity against MMP-2 was calculated by using the optimum RI 4D-QSAR model. The findings have provided interesting information to drive the designing and synthesis of novel potentially MMP-2 inhibitors against melanoma invasion.