Microfluidics for detection of exosomes and microRNAs in cancer: State of the art.

Exosomes are small extracellular vesicles with sizes ranging from 30-150 nanometers that contain proteins, lipids, mRNAs, microRNAs, and double-stranded DNA derived from the cells of origin. Exosomes can be taken up by target cells, acting as a means of cell-to-cell communication. The discovery of these vesicles in body fluids and their participation in cell communication has led to major breakthroughs in diagnosis, prognosis, and treatment of several conditions (e.g., cancer). However, conventional isolation and evaluation of exosomes and their microRNA content suffers from high cost, lengthy processes, difficult standardization, low purity, and poor yield. The emergence of microfluidics devices with increased efficiency in sieving, trapping, and immunological separation of small volumes could provide improved detection and monitoring of exosomes involved in cancer. Microfluidics techniques hold promise for advances in development of diagnostic and prognostic devices. This review covers ongoing research on microfluidics devices for detection of microRNAs and exosomes as biomarkers and their translation to point-of-care and clinical applications.

Oncogenic viruses and chemoresistance: What do we know?

Chemoresistance is often referred to as a major leading reason for cancer therapy failure, causing cancer relapse and further metastasis. As a result, an urgent need has been raised to reach a full comprehension of chemoresistance-associated molecular pathways, thereby designing new therapy methods. Many of metastatic tumor masses are found to be related with a viral cause. Although combined therapy is perceived as the model role therapy in such cases, chemoresistant features, which is more common in viral carcinogenesis, often get into way of this kind of therapy, minimizing the chance of survival. Some investigations indicate that the infecting virus dominates other leading factors, i.e., genetic alternations and tumor microenvironment, in development of cancer cell chemoresistance. Herein, we have gathered the available evidence on the mechanisms under which oncogenic viruses cause drug-resistance in chemotherapy.

Therapeutic effect of curcumin in gastrointestinal cancers: A comprehensive review.

Gastrointestinal (GI) cancers with a high global prevalence are a leading cause of morbidity and mortality. Accordingly, there is a great need to develop efficient therapeutic approaches. Curcumin, a naturally occurring agent, is a promising compound with documented safety and anticancer activities. Recent studies have demonstrated the activity of curcumin in the prevention and treatment of different cancers. According to systematic studies on curcumin use in various diseases, it can be particularly effective in GI cancers because of its high bioavailability in the gastrointestinal tract. Nevertheless, the clinical applications of curcumin are largely limited because of its low solubility and low chemical stability in water. These limitations may be addressed by the use of relevant analogues or novel delivery systems. Herein, we summarize the pharmacological effects of curcumin against GI cancers. Moreover, we highlight the application of curcumin's analogues and novel delivery systems in the treatment of GI cancers.

Plant-based vaccines and cancer therapy: Where are we now and where are we going?

Therapeutic vaccines are an effective approach in cancer therapy for treating the disease at later stages. The Food and Drug Administration (FDA) recently approved the first therapeutic cancer vaccine, and further studies are ongoing in clinical trials. These are expected to result in the future development of vaccines with relatively improved efficacy. Several vaccination approaches are being studied in pre-clinical and clinical trials, including the generation of anti-cancer vaccines by plant expression systems.This approach has advantages, such as high safety and low costs, especially for the synthesis of recombinant proteins. Nevertheless, the development of anti-cancer vaccines in plants is faced with some technical obstacles.Herein, we summarize some vaccines that have been used in cancer therapy, with an emphasis on plant-based vaccines.

Cell death pathways and viruses: Role of microRNAs.

Viral infections lead to the death of more than a million people each year around the world, both directly and indirectly. Viruses interfere with many cell functions, particularly critical pathways for cell death, by affecting various intracellular mediators. MicroRNAs (miRNAs) are a major example of these mediators because they are involved in many (if not most) cellular mechanisms. Virus-regulated miRNAs have been implicated in three cell death pathways, namely, apoptosis, autophagy, and anoikis. Several molecules (e.g., BECN1 and B cell lymphoma 2 [BCL2] family members) are involved in both apoptosis and autophagy, while activation of anoikis leads to cell death similar to apoptosis. These mechanistic similarities suggest that common regulators, including some miRNAs (e.g., miR-21 and miR-192), are involved in different cell death pathways. Because the balance between cell proliferation and cell death is pivotal to the homeostasis of the human body, miRNAs that regulate cell death pathways have drawn much attention from researchers. miR-21 is regulated by several viruses and can affect both apoptosis and anoikis via modulating various targets, such as PDCD4, PTEN, interleukin (IL)-12, Maspin, and Fas-L. miR-34 can be downregulated by viral infection and has different effects on apoptosis, depending on the type of virus and/or host cell. The present review summarizes the existing knowledge on virus-regulated miRNAs involved in the modulation of cell death pathways. Understanding the mechanisms for virus-mediated regulation of cell death pathways could provide valuable information to improve the diagnosis and treatment of many viral diseases.

Chitosan-based nanoparticles against bacterial infections.

Chitosan nanomaterials have become a hot topic in biomedicine due to exerting antimicrobial effects with interestingly high levels of biodegradability and biocompatibility without causing toxicity. Regarded as a potential means of wound dressing with antimicrobial activity, chitosan exhibits higher efficiency when it is functionally modified with other natural compounds, metallic antimicrobial particles and antibiotics. Mechanistically, the antibacterial effect of chitosan is mostly, associated with the death-proceeding leakage of intracellular content, induced by malfunction and altered permeability of the negatively charged cell membrane, on which chitosan is adsorbed. Moreover, chitosan nanoparticles (NPs) are endowed with favorable features of NPs (i.e., large surface-to-volume ratio, high functionalization possibilities and a greater capacity for drug loading), as well as that of their chitosan base, thereby possessing strengthened antibacterial potential. In addition, polycations target negatively charged bacterial membranes, so bacteria cells are more strongly affected by polycationic chitosan NPs than pure chitosan.

Biosensors for detection of Tau protein as an Alzheimer's disease marker.

Known as a main neural MAP (microtubule associated protein), tau protein contributes to stabilizing microtubules involved in cellular transmission. Tau dysfunction is mainly associated with neurodegenerative diseases, particularly Alzheimer's disease (AD). In these patients, all the six tau isoforms, which are in hyperphosphorylated form, are first aggregated and then polymerized into neurofibrillary tangles inside the brain. Tau protein detected in cerebrospinal fluid (CSF) is significantly correlated with AD and is well recognized as a hallmark of the disease. Served for detection of analytes of interest, biosensor device comprises a physical transducer and a keen biological recognition component. Qualitative and quantitative evaluations may be performed through analyzation of the data, which is gathered by measurable signals converted from biological reaction. Antibodies, receptors, microorganisms, nucleic acids, enzymes, cells and tissues, as well as some biomimetic structures, normally constitute the biosensor biological recognition part. Production of nanobiosensor, which was made possible through several accomplishments in nano- and fabrication technology, opens up new biotechnological horizons in diagnosis of multiple diseases. In recent years, many researches have been focused on developing novel and effective tau protein biosensors for rapid and accurate detection of AD. In this review, tau protein function and correlation with AD as well as the eminent research on developing nanobiosensor based on optical, electrochemical and piezoelectric approaches will be highlighted.