Doxorubicin (Dox) is a secondary metabolite of the mutated strain of Streptomyces peucetius var. Caesius and belongs to the anthracyclines family. The anti-cancer activity of Dox is mainly exerted through the DNA intercalation and inhibiting topoisomerase II enzyme in fast-proliferating tumors. However, Dox causes cumulative and dose-dependent cardiotoxicity, which results in increased risks of mortality among cancer patients and thus limiting its wide clinical applications. There are several mechanisms has been proposed for doxorubicin-induced cardiotoxicity and oxidative stress, free radical generation and apoptosis are most widely reported. Apart from this, other mechanisms are also involved in Dox-induced cardiotoxicity such as impaired mitochondrial function, a perturbation in iron regulatory protein, disruption of Ca2+ homeostasis, autophagy, the release of nitric oxide and inflammatory mediators and altered gene and protein expression that involved apoptosis. Dox also causes downregulation of DNA methyltransferase 1 (DNMT1) enzyme activity which leads to a reduction in the DNA methylation process. This hypomethylation causes dysregulation in the mitochondrial genes like peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1-alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) unit in the heart. Apart from DNA methylation, Dox treatment also alters the micro RNAs levels and histone deacetylase (HDAC) activity. Therefore, in the current review, we have provided a detailed update on the current understanding of the pathological mechanisms behind the well-known Dox-induced cardiotoxicity. Further, we have provided some of the most plausible pharmacological strategies which have been tested against Dox-induced cardiotoxicity.
Nanoparticles (NPs) serve to reduce the toxicity, enhance bioactivity, improve targeting, and provide versatile means to control the release profile of the encapsulated moiety. Among different NPs, inorganic NPs of metals like Ag, Au, Ce, Fe, Se, Ti and Zn possess a significant place owing to their unique bioactivities in nanoforms. Selenium (Se) is an essential trace element. It is incorporated into selenoproteins as selenocysteine (Sec) representing the most important part of the active center of their enzymatic activities. Many selenoproteins have oxidoreductase activity and, thus, regulate the physiological redox balance. Se has a narrow therapeutic window and the toxicity margins are very delicate whereas the nanoparticles of Se (SeNPs) possess remarkably reduced toxicity. SeNPs have been explored in various oxidative stress and inflammation mediated disorders like arthritis, cancer, diabetes and nephropathy with potential therapeutic benefits. SeNPs constitute an attractive carrier platform to ferry various drugs to the site of action. Herein we have discussed the significance of nanosizing on the pharmacological activity of Se. The role of SeNPs in pharmacological protection against various inflammatory and oxidative stress mediated conditions is presented. However, it is largely unknown how SeNPs may affect the pharmacokinetics and pharmacodynamics of selenoproteins. Most of the available studies were poorly designed without any comparison to the other Se sources. In the future, detailed studies with inclusion of an appropriate source of Se should be carried out with emphasis on understanding the role of selenoproteins in the observed pharmacological activity.
Apoptosis is an evolutionarily conserved sequential process of cell death to maintain a homeostatic balance between cell formation and cell death. It is a vital process for normal eukaryotic development as it contributes to the renewal of cells and tissues. Further, it plays a crucial role in the elimination of unnecessary cells through phagocytosis and prevents undesirable immune responses. Apoptosis is regulated by a complex signaling mechanism, which is driven by interactions among several protein families such as caspases, inhibitors of apoptosis proteins, B-cell lymphoma 2 (BCL-2) family proteins, and several other proteases such as perforins and granzyme. The signaling pathway consists of both pro-apoptotic and pro-survival members, which stabilize the selection of cellular survival or death. However, any aberration in this pathway can lead to abnormal cell proliferation, ultimately leading to the development of cancer, autoimmune disorders, etc. This review aims to elaborate on apoptotic signaling pathways and mechanisms, interacting members involved in signaling, and how apoptosis is associated with carcinogenesis, along with insights into targeting apoptosis for disease resolution.
Liver fibrosis is one of the leading complications of a variety of chronic liver disorders, including the nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, liver cirrhosis and liver failure. The progression of liver fibrosis is driven by chronic inflammation, which activates the secretory fibroblasts to the myofibroblast phenotype. These specialized liver cells are called as hepatic stellate cells (HSCs). The excessive extracellular matrix (ECM) secretion creates a large number of complications. Fibrosis is the result of imbalance between the matrix synthesizing and matrix degrading factors. The major ECM proteins include the matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs), lysyl oxidases (LOX), lysyl oxidase-like (LOXLs) enzymes, tenascins and others. These ECM proteins present novel avenues for the therapeutics of liver fibrosis. The current review highlights the major role played by these critical matrix proteins in liver fibrosis. Further, some of the targeted formulations used against these proteins are discussed and suggestions are provided to select the course of research for successful clinical translation of basic research findings for the amelioration of liver fibrosis.