Synthesis, optical, electrochemical, and computational study of benzene/thiophene based D-π-A chromophores.

We report the design, synthesis, electrochemical, UV-vis, fluorescence, and computational study of nine π-linked donor-acceptor (D-π-A) chromophores. The series of novel compounds comprises a terphenyl, terthiophene, or 2,5-diphenyl thiophene linker, with one electron-donating group (methyl or ,-diethyl) and one electron-withdrawing group (nitrone, formyl, or dicyanovinyl) at opposite ends of the molecule. The HOMO-LUMO gaps were determined cyclic voltammetry and found to correspond well to DFT-calculated values.

Epigenetic deregulation in breast cancer microenvironment: Implications for tumor progression and therapeutic strategies.

Breast cancer comprises a substantial proportion of cancer diagnoses in women and is a primary cause of cancer-related mortality. While hormone-responsive cases generally have a favorable prognosis, the aggressive nature of triple-negative breast cancer presents challenges, with intrinsic resistance to established treatments being a persistent issue. The complexity intensifies with the emergence of acquired resistance, further complicating the management of breast cancer.

Novel model of triple-negative breast cancer produces viable circulating tumor cells and rapid lung metastasis for functional testing in vivo.

Breast cancer metastases are the main reason for women´s highest cancer mortality. Even though tumor cell dissemination via circulating tumor cells (CTC) released from the primary site is a very ineffective process, distant metastases appear in 46% of triple-negative breast cancer (TNBC) patients corresponding to the disease aggressiveness. Laboratory models for functional testing which mimic the spread of metastatic cells are needed for efficient investigation of the underlying mechanisms and therapeutic intervention.

The third dimension of tumor microenvironment-The importance of tumor stroma in 3D cancer models.

Recent advances in the three-dimensional (3D) cancer models give rise to a plethora of new possibilities in the development of anti-cancer drug therapies and bring us closer to personalized medicine. Three-dimensional models are undoubtedly more authentic than traditional two-dimensional (2D) cell cultures. Nowadays, they are becoming preferentially used in most cancer research fields due to their more accurate biomimetic characteristics.

Decitabine potentiates efficacy of doxorubicin in a preclinical trastuzumab-resistant HER2-positive breast cancer models.

Acquired drug resistance and metastasis in breast cancer (BC) are coupled with epigenetic deregulation of gene expression. Epigenetic drugs, aiming to reverse these aberrant transcriptional patterns and sensitize cancer cells to other therapies, provide a new treatment strategy for drug-resistant tumors. Here we investigated the ability of DNA methyltransferase (DNMT) inhibitor decitabine (DAC) to increase the sensitivity of BC cells to anthracycline antibiotic doxorubicin (DOX).

Chemotherapy-triggered changes in stromal compartment drive tumor invasiveness and progression of breast cancer.

Background: Chemotherapy remains a standard treatment option for breast cancer despite its toxic effects to normal tissues. However, the long-lasting effects of chemotherapy on non-malignant cells may influence tumor cell behavior and response to treatment. Here, we have analyzed the effects of doxorubicin (DOX) and paclitaxel (PAC), commonly used chemotherapeutic agents, on the survival and cellular functions of mesenchymal stromal cells (MSC), which comprise an important part of breast tumor microenvironment.

NiO Nanoparticles for Electrochemical Insulin Detection.

Diabetes mellitus represents one of the most widespread diseases in civilization nowadays. Since the costs for treating and diagnosing of diabetes represent several billions of dollars per year, a cheap, fast, and simple sensor for diabetes diagnosis is needed. Electrochemical insulin sensors can be considered as a novel approach for diabetes diagnosis.

The Role of -Mutated Tumor Microenvironment in Breast Cancer.

Taking into account the factors of high incidence rate, prevalence and mortality, breast cancer represents a crucial social and economic burden. Most cases of breast cancer develop as a consequence of somatic mutations accumulating in mammary epithelial cells throughout lifetime and approximately 5-10% can be ascribed to monogenic predispositions. Even though the role of genetic predispositions in breast cancer is well described in the context of genetics, very little is known about the role of the microenvironment carrying the same aberrant cells impaired by the germline mutation in the breast cancer development and progression.

Dramatic changes in the electrochemical and spectroscopic behavior of DNA fragments induced by the loss of a single nucleotide.

In this paper, the d(GCGAAGC) heptamer and the closely related d(GCGAGC) hexamer are examined via electrochemical (cyclic voltammetry) and spectroscopic (circular dichroism) methods. Dramatic changes in the CD spectroscopic and CV electrochemical properties, induced by the loss of only one single nucleotide (A), are detected. The CD spectra and native polyacrylamide gel electrophoresis (PAGE) confirmed structural changes taking place in the relevant chain-like oligodeoxynucleotide assemblies.

Influence of a polymer membrane on the electrochemical determination of insulin in nanomodified screen printed carbon electrodes.

Diabetes mellitus can be considered one of the most widespread diseases globally. Hence, the diabetes research is currently focused on developing an effective, low-cost sensor having high stability and suitable analytical characteristics. Screen printed carbon electrodes (SPCEs) embody ideal candidates for insulin determination due to the small area of the working electrode eliminating the solution volume required for the given purpose.

Nanoparticle-Based Immunochemical Biosensors and Assays: Recent Advances and Challenges.

We review the progress achieved during the recent five years in immunochemical biosensors (immunosensors) combined with nanoparticles for enhanced sensitivity. The initial part introduces antibodies as classic recognition elements. The optical sensing part describes fluorescent, luminescent, and surface plasmon resonance systems.

G-quadruplex-based structural transitions in 15-mer DNA oligonucleotides varying in lengths of internal oligo(dG) stretches detected by voltammetric techniques.

Electrochemical methods, particularly when applied in connection with mercury-containing electrodes, are excellent tools for studying nucleic acids structure and monitoring structural transitions. We studied the effect of the length of the central (dG) n stretch (varying from 0 to 15 guanine residues) in 15-mer oligodeoxynucleotides (ODN, G0 to G15) on their electrochemical and interfacial behavior at mercury and carbon electrodes. The intensity of guanine oxidation signal at the carbon electrode (peak G(ox)) was observed to increase continuously with number of guanines between 0 and 15, with only a slight positive shift for ODNs with seven or more guanines in the central segment.

Oxidation as an important factor of protein damage: Implications for Maillard reaction.

Protein oxidation, the process caused especially by reactive oxygen and nitrogen species, is thought to play a major role in various oxidative processes within cells and is implicated in the development of many human diseases. This review provides a brief overview of the protein oxidation with the emphasis on the types of oxidation (oxidation of protein backbone and amino acid residues side chains, site-specific metal-catalysed protein oxidation), oxidationdependent generation of protein hydroperoxides, carbonyl derivatives and protein-protein cross-linkages. Nonenzymatic glycoxidation (also known as Maillard reaction) as an important factor of protein damage, consequences of oxidative protein impairment and related diseases as well as means of monitoring and assessment of protein modifications are discussed.

Novel biophysical determination of miRNAs related to prostate and head and neck cancers.

In this study we have chosen a new approach and characterized three miRNAs (miR-23a, miR-34a and miR-320a) related to prostate cancer and head and neck cancer by spectral (circular dichroic and UV-absorption spectra) and electrochemical (voltammetry at graphite and mercury electrodes) methods. The spectral and voltammetric results, reflecting different nucleotide sequences of miRNAs, were complemented by the results of DNAs(U) having the same oligonucleotide sequences as miRNAs. The effect of the substitution of ribose for deoxyribose was shown and structural diversity was confirmed.

Functionalized solid electrodes for electrochemical biosensing of purine nucleobases and their analogues: a review.

Interest in electrochemical analysis of purine nucleobases and few other important purine derivatives has been growing rapidly. Over the period of the past decade, the design of electrochemical biosensors has been focused on achieving high sensitivity and efficiency. The range of existing electrochemical methods with carbon electrode displays the highest rate in the development of biosensors.

eL-Chem Viewer: a freeware package for the analysis of electroanalytical data and their post-acquisition processing.

In electrochemical sensing, a number of voltammetric or amperometric curves are obtained which are subsequently processed, typically by evaluating peak currents and peak potentials or wave heights and half-wave potentials, frequently after background correction. Transformations of voltammetric data can help to extract specific information, e.g.

Study of metallothionein-quantum dots interactions.

Nanoparticles have gained increasing interest in medical and in vivo applications. Metallothionein (MT) is well known as a maintainer of metal ions balance in intracellular space. This is due to high affinity of this protein to any reactive species including metals and reactive oxygen species.

Influence of Magnetic Microparticles Isolation on Adenine Homonucleotides Structure.

The electroactivity of purine and pyrimidine bases is the most important property of nucleic acids that is very useful for determining oligonucleotides using square wave voltammetry. This study was focused on the electrochemical behavior of adenine-containing oligonucleotides before and after their isolation using paramagnetic particles. Two peaks were detected-peak A related to the reduction of adenine base and another peak B involved in the interactions between individual adenine strands and contributes to the formation of various spatial structures.

DNA interaction with zinc(II) ions.

We focused on interactions of Zn(II) with DNA in this study. These interactions were monitored using UV/vis spectrophotometry and gel electrophoresis. Firstly, we isolated and amplified 498 bp fragment of DNA.

Investigation of interaction between magnetic silica particles and lambda phage DNA fragment.

Nucleic acids belong to the most important molecules and therefore the understanding of their properties, function and behavior is crucial. Even though a range of analytical and biochemical methods have been developed for this purpose, one common step is essential for all of them - isolation of the nucleic acid from the from complex sample matrix. The use of magnetic particles for the separation of nucleic acids has many advantages over other isolation methods.

Electrochemical study of ellipticine interaction with single and double stranded oligonucleotides.

Ellipticine (5,11-dimethyl-6H-pyrido[4,3-b]carbazole) is an alkaloid that has been isolated from plants of an Apocynaceae family. It is one of the simplest naturally occurring alkaloids with a planar structure. Over the past decades, ellipticine became a very promising antitumor agent.

Development of a magnetic electrochemical bar code array for point mutation detection in the H5N1 neuraminidase gene.

Since its first official detection in the Guangdong province of China in 1996, the highly pathogenic avian influenza virus of H5N1 subtype (HPAI H5N1) has reportedly been the cause of outbreaks in birds in more than 60 countries, 24 of which were European. The main issue is still to develop effective antiviral drugs. In this case, single point mutation in the neuraminidase gene, which causes resistance to antiviral drug and is, therefore, subjected to many studies including ours, was observed.

Green tea catechins can bind and modify ERp57/PDIA3 activity.

Background: Green tea is a rich source of polyphenols, mainly catechins (flavanols), which significantly contribute to the beneficial health effects of green tea in the prevention and treatment of various diseases. In this study the effects of four green tea catechins on protein ERp57, also known as protein disulfide isomerase isoform A3 (PDIA3), have been investigated in an in vitro model.

Methods: The interaction of catechins with ERp57 was explored by fluorescence quenching and surface plasmon resonance techniques and their effect on ERp57 activities was investigated.