Current Pharmaceutical Design - Volume 24, Issue 28, 2018

PEG-functionalized nanoparticles as carriers of chemotherapeutics agents have been explored with notable successes in preclinical and clinical stages of cancer treatment, with some already approved by FDA, namely PEGylated liposomes and polymers. Half-life extension of therapeutic agents through PEGylation process improves their pharmacokinetic (PK) profiles, thereby reducing their dosing frequency. Protein corona composition of PEGylated nanoparticles (NPs) confers a tremendous influence on their surface characteristics which directly impact tumor accumulation and clearance properties of the drugs. By controlling the size and complexity of PEG molecules, as well as by attaching targeting moieties, the surface characteristics of NPs can be manipulated to improve their tumor uptake without sacrificing the circulation time. This review focuses on design and applications of PEGylated NPs for tumor targeted drug delivery in animal models and clinical setting.

Cancer-associated fibroblasts (CAFs) are an important cell type present in solid tumor microenvironments, including that of gastric cancer. They play a vital role in the promotion of tumorigenesis, angiogenesis, and cancer progression through paracrine signaling and modulation of the extracellular matrix. However, the exact molecular mechanism underlying the interaction between gastric cancer cells and stromal fibroblasts remains poorly understood. Recent studies have demonstrated that various factors, such as gene and microRNA variations, are involved in this process. This review discusses recent advances in understanding how these factors are regulated in CAFs and how they affect tumor biology, which may improve our understanding of their role in gastric cancer tumorigenesis and progression and provide new promising targets for therapeutic strategies.

Background: Among the numerous bio-responsive polymeric drug delivery systems developed recently, redox-triggered release of molecular payloads have gained great deal of attention, especially in the field of anticancer drug delivery. In most cases, these systems rely on disulfide bonds located either in the matrix crosslinks, or in auxiliary chains to achieve stimuli-responsive drug release. These bonds keep their stability in extracellular environments, yet, rapidly break by thiol–disulfide exchange reactions in the cytosol, due to the presence of greater levels of glutathione. Polysaccharides are macromolecules with low cost, natural abundance, biocompatibility, biodegradability, appropriate physical and chemical properties, and presence of numerous functional groups which facilitate chemical or physical cross-linking. Methods: With regards to the remarkable advantages of polysaccharides, in the current study, various polysaccharide-based redox-responsive drug delivery systems are reviewed. In most cases the in vitro/in vivo effects of the developed system were also evaluated. Results: Considering the hypoxic and reducing nature of the tumor microenvironment, with several folds higher glutathione levels than the systemic tissues, redox-sensitive polymeric systems could be implemented for tumorspecific drug delivery and the results of the previous researches in this field indicated satisfactory achievements. Conclusion: According to the reviewed papers, the efficiency of diverse redox-responsive polysaccharide-based nanoparticles with therapeutic payloads in cancer chemotherapy could be concluded. Nevertheless, more comprehensive studies are required to understand the exact intracellular and systemic fate of these nano-carriers, as well as their clinical efficacy for cancer treatment.

Background: Breast cancer is the most frequently diagnosed malignancy in women worldwide. Breast cancer tends to metastasize to bone. Around 70% of the breast cancer patients eventually develop bone metastasis. After the bone invasion, metastatic cells disrupt the balance between osteoblastic and osteoclastic activities, leading to skeletal complications, characterized by pain and pathological fractures and hence worsening the patient's quality of life. Once tumor invades the bone, it is hard to treat it with, the so-far available treatments options (e.g. bisphosphonates and denosumab). Bone metastasis should be essentially controlled, in cancer treatment and there is a strong need to explore new, more efficient therapeutic targets. This review discusses the bone physiological processes and the recent advances in exploring different pathways involved in bone metastasis. Furthermore, some novel treatment options, which are under preclinical and clinical investigations, are highlighted. Conclusion: A deeper understanding of these metastatic pathways can provide oncology researchers with novel avenues for treating bone metastasis, one of the main challenges to cure breast cancer. The restoration of healthy bone environment will not only improve the patient's quality of life but also reduces the tumor burden.

Stroke is a leading cause of death and disability worldwide. Conventional treatment has a limitation of very narrow therapeutic time window and its devastating nature necessitate a novel regenerative approach. Transplanted stem cells resulted in functional recovery through multiple mechanisms including neuroprotection, neurogenesis, angiogenesis, immunomodulation, and anti-inflammatory effects. Despite the promising features shown in experimental studies, results from clinical trials are inconclusive from the perspective of efficacy. The present review presents a synopsis of stem cell research on ischemic stroke treatment according to cell type. Clinical trials to the present are briefly summarized. Finally, the hurdles and issues to be solved are discussed for clinical application.

In recent years, Aβ aggregation prevention, one of the most concerned strategies in drug development has been carefully assessed to treat Alzheimer's disease. Aβ peptides can transform structurally from random coil monomer into β-stranded protofibril via multiple oligomeric states. Among the various Aβ species, the identification of binding targets has been challenging due to the heterogeneity and metastable nature. A better understanding of Aβ species' assembly details and structural properties has been more characterized recently. Numerous potential inhibitors have been identified that they can effectively bind to different Aβ species such as monomer, oligomer or protofibril during the inhibition of Aβ aggregation process. This review highlights the diversity of structural ensembles of Aβ species, from monomer to protofibril forms and the specific binding targets by their potential inhibitors. Comprehending the binding mechanism of Aβ inhibitors is indispensable for searching novel drug candidates against early-stage Alzheimer's disease.

Background: Virtual Screening (VS) has emerged as an important tool in the drug development process, as it conducts efficient in silico searches over millions of compounds, ultimately increasing yields of potential drug leads. As a subset of Artificial Intelligence (AI), Machine Learning (ML) is a powerful way of conducting VS for drug leads. ML for VS generally involves assembling a filtered training set of compounds, comprised of known actives and inactives. After training the model, it is validated and, if sufficiently accurate, used on previously Objective: The study aims to review ML-based methods used for VS and applications to Alzheimer’s Disease (AD) drug discovery. Methods: To update the current knowledge on ML for VS, we review thorough backgrounds, explanations, and VS applications of the following ML techniques: Naïve Bayes (NB), k-Nearest Neighbors (kNN), Support Vector Machines (SVM), Random Forests (RF), and Artificial Neural Networks (ANN). Results: All techniques have found success in VS, but the future of VS is likely to lean more largely toward the use of neural networks – and more specifically, Convolutional Neural Networks (CNN), which are a subset of ANN that utilize convolution. We additionally conceptualize a work flow for conducting ML-based VS for potential therapeutics for AD, a complex neurodegenerative disease with no known cure and prevention. This both serves as an example of how to apply the concepts introduced earlier in the review and as a potential workflow for future implementation. Conclusion: Different ML techniques are powerful tools for VS, and they have advantages and disadvantages albeit. ML-based VS can be applied to AD drug development.

Background: Oxidative stress and inflammatory response played important roles in advanced atherosclerosis. We tried to confirm clinical diagnostic significance of the assessments of oxidative stress and inflammatory response status with in-stent reocclusion in 283 advanced age patients (80#158;90 years) after coronary stenting. Methods: We analyzed levels of circulating superoxide dismutase 3 (SOD3), nitric oxide (NO), endothelial nitric oxide synthase (eNOS), malondialdehyde (MDA), acrolein#136;ACR#137;, and paraoxonase-1 #136;PON-1#137;in advanced age patients with in-stent restenosis and reocclusion after coronary stenting. Results: Levels of SOD3, eNOS, NO and PON-1 were lowered (P<0.001) and levels of MDA and ACR were increased (P<0.001). Conclusion: The assessments of the biomarkers of oxidative stress and inflammatory response (levels of MDA and ACR) and anti-oxidant biomarkers (levels of eNOS, NO, SOD3 and PON-1) could be considered as potential prognostic and diagnostic indicators of in-stent reocclusion in advanced age patients after coronary stenting.

Background: Triple-Negative Breast Cancer is an aggressive type of breast cancer, which is not treatable by chemotherapy drugs, due to the lack of Estrogen Receptor (ER), Progesterone Receptor (PR) expression and Human Epidermal Growth Factor Receptor 2 (HER2) on the cell surface. Objective: The aim of this study was to compare the effect of paclitaxel loaded PLGA nanoparticle (PTX-NPs) on the cytotoxicity and apoptosis of the different MDA-MB type of cell lines. Method: PTX-NPs were prepared by nanoprecipitation method and characterized earlier. The cytotoxicity of PTX-NPs was evaluated by MTT and LDH assay, later apoptosis was calculated by flow cytometry analysis. Results: The prepared NP size of 317.5 nm and zetapontial of -12.7 mV showed drug release of 89.1 % at 48 h. MDA-MB-231 type cell showed significant cytotoxicity by MTT method of 47.4 ± 1.2 % at 24 h, 34.6 ± 0.8 % at 48 h and 23.5 ± 0.5 % at 72 h and LDH method of 35.9 ± 1.5 % at 24 h, 25.4 ± 0.6 % at 48 h and 19.8 ± 2.2 % at 72 h with apoptosis of 47.3 ± 0.4 %. Conclusion: We have found that PTX-NPs showed the cytotoxic effect on all the MDA-MB cancer cell lines and showed potent anticancer activities against MDA-MB-231 cell line via induction of apoptosis.

Background: Recently, we identified the circadian rhythm protein Period 2 (PER2) in robust cardioprotection from myocardial ischemia (MI). Based on findings that perioperative MI is the most common major cardiovascular complication and that anesthetics can alter the expression of PER2, we hypothesized that an anesthesia mediated downregulation of PER2 could be detrimental if myocardial ischemia and reperfusion (IR) would occur. Methods and Results: We exposed mice to pentobarbital, fentanyl, ketamine, propofol, midazolam or isoflurane and determined cardiac Per2 mRNA levels. Unexpectedly, only midazolam treatment resulted in an immediate and significant downregulation of Per2 transcript levels. Subsequent studies in mice pretreated with midazolam using an in-situ mouse model for myocardial (IR)-injury revealed a significant and dramatic increase in infarct sizes or Troponin-I serum levels in the midazolam treated group when compared to controls. Using the recently identified flavonoid, nobiletin, as a PER2 enhancer completely abolished the deleterious effects of midazolam during myocardial IR-injury. Moreover, nobiletin treatment alone significantly reduced infarct sizes or Troponin I levels in wildtype but not in Per2-/- mice. Pharmacological studies on nobiletin like flavonoids revealed that only nobiletin and tangeritin, both found to enhance PER2, were cardioprotective in our murine model for myocardial IR-injury. Conclusion: We identified midazolam mediated downregulation of cardiac PER2 as an underlying mechanism for a deleterious effect of midazolam pretreatment in myocardial IR-injury. These findings highlight PER2 as a cardioprotective mechanism and suggest the PER2 enhancers nobiletin or tangeritin as a preventative therapy for myocardial IR-injury in the perioperative setting where midazolam pretreatment occurs frequently.

Background: Anticholinergic and sedative drugs are associated with adverse events such as cognitive and functional impairment in elderly. The Drug Burden Index (DBI) is a measure of an individual's total exposure to anticholinergic and sedative drugs. Objetive: The study aimed to evaluate the association between the total DBI and cognitive and functional impairment in patients with multimorbidity. Setting: Patients with multimorbidity enrolled in the IMPACTO project. Methods: Cross-sectional observational study. Main outcome measure: The anticholinergic and sedative exposure was calculated using DBI. The Pfeiffer Test (PT) was used for cognitive status and the Barthel Index (BI) for functional status. Results: 336 patients were included (mean age 77.6 ± 8.7 years, 54.2% men and a mean of 11.5 ± 3.7 prescribed drugs). 180 patients (53.6%) exposed to anticholinergic and/or sedative drugs were identified. The median score obtained in PT was slightly higher in exposed patients (1 (IQR 0-2) and 2 (IQR 0-4), p = 0.082 in "non-exposed" and "exposed", respectively). The bivariate analysis showed an association [0.544 (95% CI 0.044-1.063, p = 0.03)]. The median obtained in the BI analysis was 85.0 (IQR 30.0) and 75.5 (IQR 42.5) p = 0.002, in "nonexposed" and "exposed", respectively. After the adjusted analysis, a relationship was obtained between both the variables [-9,558 (95% CI-15,794; -3,321, p = 0.03)]. Conclusion: Higher DBI is associated with the impairment of functional status and, slightly to the deterioration of cognitive function in patients with multimorbidity. DBI should be considered in patients with multimorbidity to optimize the pharmacological treatment of a group of special interest due to its vulnerability.