Current Pharmaceutical Design - Volume 24, Issue 5, 2018

Cell Penetrating Peptides (CPPs) equipped with a high penetrating ability are used as a promising tool to gain access to the cell interior, cross the cell membrane and deliver bioactive small or macromolecular cargos into the cytoplasm or nucleus. The superiority of wide range of applications, high transport efficiency and low biological toxicity make them particularly desirable in laboratory or clinical studies. Previous studies have shown that their non-selectivity and reaction with proteins in plasma hamper their application for tumor therapy, which might adversely affect the treatment effect and even induce some side effects. However, several recent studies have found that various kinds of modifiers of CPPs can effectively increase the target selectivity, reduce cytotoxicity to normal cells and produce multiple antitumor functions due to the different cleavable bonds which are sensitive to the tumor microenvironment or other novel designs. Apparently, these designs of ‘smart’ CPPs appear to be promising in the field of antitumor drug delivery. Here, we review these current improved approaches which mainly involve strategies of physical, chemical as well as biological pathways and we also explain the possible uptake mechanisms of direct penetration, internalization and escape which have been discussed in some publications with specific attention. In addition, some possible problems needed to be considered in the process of improving CPPs are discussed at the end of this review. This study aims to present an overview of the latest progress of CPPs, and provides a comprehensive theoretical background and reference guidance for future laboratory research and clinical application.

Melanoma is the deadliest form of skin cancer being responsible for 80% of skin cancer deaths. Furthermore, the incidence of metastatic melanoma has increased over the past three decades with a mortality rate that continues to rise faster than most of all other cancers. The last few years have witnessed an unparalleled change in treatment options for patients with metastatic melanoma by the development of new therapeutic strategies like targeted therapies and immunotherapies that highly improved the patient's prognosis. Despite the paradigm- shifting success of these novel treatments, their effectiveness is still limited by intrinsic or acquired resistance. The objective of this review is to provide an overview of the new available treatment modalities, criteria to select patients who might benefit from a specific therapy, mechanisms of innate and acquired resistance to these treatments and to discuss strategies to overcome drug resistance.

Background: Lymph nodal (LN) metastasis, classified as pN1b, is considered as an independent poor prognostic factor for Papillary thyroid carcinoma (PTC) patients. However, whether LN metastasis can serve as a predictive factor for recurrence or disease-free survival of N1b PTC is still plagued by controversy. Methods: The N1b PTC patients who underwent total thyroidectomy and unilateral modified radical neck dissection (MRND) by the same surgical team in Ningbo NO.2 Hospital from March, 1998 to March, 2015 were included in this study. The clinical and pathological characteristics of each patient were recorded in detail. Univariate and multivariate Cox proportional hazards regression models were performed to analyze the associations between clinicopathological characteristics with recurrence. Kaplan–Meier analysis and log-rank test were used for the analysis of overall RFS and level V metastasis. Results: A total of 214 patients were eligible for the final analyses. Of the 214 finally included patients with N1b PTC, 39 patients were classified with recurrence and 175 without recurrence. The final univariate and multiple Cox proportional hazards analysis only suggested level V metastasis as the independent predictive factor of N1b PTC recurrence (HR: 4.11; 95% CI:1.22–11.05, P=0.028). The patients with level V metastasis showed a significantly lower 10-year RFS rate (P=0.031) as illustrated by Kaplan–Meier analysis and log-rank test. Conclusion: Level V metastasis is a novel indicator for tumor recurrence and 10-year RFS in patients with N1b PTC.

Background: Multiple myeloma is the second most prevalent hematologic malignancy and thought to be incurable. Therefore, it's urgent to find new drugs for treatment. Some experiments have shown that curcumin might have great potential in treating multiple myeloma, while the mechanism is still unknown. EZH2 and SUZ12 are the core proteins in PRC2 and their expressions are increased in various human cancers, including the poor prognostic multiple myeloma. Meanwhile, the regulation of miRNAs and EZH2 has been demonstrated in other cancer researches, like lung cancer, pancreatic cancer, leukemia and so on. Objective: To reveal the mechanism behind the anti-tumor effect of cucurmin in multiple myeloma. Method: The effect of curcumin on the growth of MM cells was studied by MTT assay in the MM cell lines RPMI8226 and U266. Apoptosis was measured by Annexin V-FITC/PI double staining method. Western blotting, RT-PCR and luciferase activity assay were used to assess the expression of EZH2, SUZ12, miR-101 and downstream proteins such as E-cadherin, MMP9, c-Myc, cyclin D3, CDK4 and CDK6. Results: Curcumin could significantly inhibite the proliferation of MM cells in a time- and concentrationdependent manner. Curcumin induced apoptosis by inhibiting the expression of EZH2, and the apoptosis rates were 16.42% and 25.62% when the RPMI8226 cells incubated with 5 and 10 μmol/L of curcumin. For U266 cells, the apoptosis rates were 15.25% and 21.28%. The up-regulation of miR-101 led to the lower expression of EZH2. In adverse, the expression of EZH2 induced lower expression of miR-101. The down-stream proteins of miR-101 were regulated by curcumin and EZH2 at the same time. Conclusion: Our experiments verified that the effect and mechanism of curcumin on multiple myeloma is via EZH2 – miR-101 regulatory feedback loop, which would lead us to a new way of investigating multiple myeloma and come up with new therapies in treating the disease.

About 132 thousand cases of melanoma (more severe type of skin cancer) were registered in 2014 according to the World Health Organization. This type of cancer significantly affects the quality of life of individuals. Caffeine has shown potential inhibitory effect against epithelial cancer. In this study, it was proposed to obtain new caffeine-based molecules with potential epithelial anticancer activity. For this, a training set of 21 molecules was used for pharmacophore perception procedures. Multiple linear regression analyses were used to propose mono-, bi-, tri-, and tetra-parametric models applied in the prediction of the activity. The generated pharmacophore was used to select 350 molecules available at the ZINCpharmer server, followed by reduction to 24 molecules, after selection using the Tanimoto index, yielding 10 molecules after final selection by predicted activity values > 1.5229. These ten molecules had better pharmacokinetic properties than the other ones used as reference and within the clinically significant limits. Only two molecules show minor hits of toxicity and were submitted to molecular docking procedures, showing BFE (binding free energy) values lower than the reference values. Statistical analyses indicated strong negative correlations between BFE and pharmacophoric properties (high influence on BFE lowering) and practically null correlation between BFE and BBB. The two most promising molecules can be indicated as candidates for further in vitro and in vivo analyzes.

Background: Potassium bromate (KBrO3), a food additive, has been used in many bakery products as an oxidizing agent. It has been shown to induce renal cancer in many in-vitro and in-vivo experimental models. Objectives: This study evaluated the carcinogenic potential of potassium bromate (KBrO3) and the chemopreventive mechanisms of the anti-oxidant and anti-inflammatory phytochemical, curcumin against KBrO3-induced carcinogenicity. Method: Lactate dehydrogenase (LDH) cytotoxicity assay and morphological characteristics were used to assess curcumin's cytoprotective potential against KBrO3 toxicity. To assess the chemopreventive potential of curcumin against KBrO3-induced oxidative insult, intracellular H2O2 and the nuclear concentration of the DNA adduct 8- OHdG were measured. PCR array, qRT-PCR, and western blot analysis were used to identify dysregulated genes by KBrO3 exposure. Furthermore, immunofluorescence was used to evaluate the ciliary loss and the disturbance of cellular tight junction induced by KBrO3. Results: Oxidative stress assays showed that KBrO3 increased the levels of intracellular H2O2 and the DNA adduct 8-OHdG. Combination of curcumin with KBrO3 efficiently reduced the level of H2O2 and 8-OHdG while upregulating the expression of catalase. PCR array, qRT-PCR, and western blot analysis revealed that KBrO3 dysregulated multiple genes involved in inflammation, proliferation, and apoptosis, namely CTGF, IL-1, and TRAF3. Moreover, qRT-PCR and immunofluorescence studies showed that KBrO3 negatively affected the tight junctional protein (ZO-1) and induced a degeneration of primary ciliary proteins. The negative impact of KBrO3 on cilia was markedly repressed by curcumin. Conclusion: Curcumin could potentially be used as a protective agent against carcinogenicity of KBrO3.

Background: Paraoxonase (PON) is a family of calcium-dependent hydrolases, which is related to many diseases. Elucidation of PON physiological roles, active center and all applications in medical fields are dependent on its substrates. Objective: The reports about PON substrates scattered in a long span of period are collected to afford clue for drug design, diagnosis of PON status and other academic purposes. Method: PON substrates from 133 references are classified and compared. Structurally, PON substrates are generally classified as organic phosphorous esters, lactones and arylesters. Some phosphoramidates, organophosphorous obidoximes, aryl carboxylic acid amides and special fatty alcohol esters as PON substrates are also included. Results: The electron nature, steric hindrance and hydrophilicity of substrate substituents affecting the PON catalytic ability, binding ability and specificities are discussed. Drugs, prodrugs and naturally endogenous molecules in life processes activated or inactivate by PON are reviewed. Interestingly, some organophosphate and lactone substrates are preferably hydrolyzed by one of the PON1R192Q allozymes, and such a substrate is generally essential for differentiating the three PON1192R phenotypes by using a dual-substrate method. Intricately, some chiral substrates are hydrolyzed by PON stereoselectively. Conclusion: As more substrates are synthesized and characterized, more facts about PON structure and catalytic properties (including PON active center and catalytic mechanism) will be revealed, and therefore the use of PON as a drug target or as an accurate disease marker will be achieved.

Background: Platelet hyperactivity has been implicated in many cardiovascular (CV) events such as ischemic stroke, myocardial infarction and CV death. Genetic variability of platelet receptors has been shown to impact Src family kinases (SFKs) activation and in turn influence platelet activation. SFKs are important signal transmitters in platelets, interacting with several receptors as GPIIB/IIIa, GPIb, PEAR 1, GPIa, GPVI, PECAM and CD148. Methods: In this review, we focused on genetic variants of platelet receptors whose signals are transmitted mainly by SFKs and may be associated with clinical manifestations of platelet hyperactivation like MI or IS. Results: The genetic variants of platelet receptors, the signals of which are transmitted by SFKs, and the associated clinical manifestations in platelet hyperactivation, have been examined. The most extensively studied receptors were glycoprotein polymorphisms. The greatest numbers of genetic variants were analyzed in GPIb. GPIIb/IIIa receptor polymorphisms were also well analyzed and many studies highlighted their associations with ischemic stroke (IS) and myocardial infarction (MI). However, there are a number of conflicting studies finding that GPIIb/IIIa receptor polymorphisms may not influence platelet hyperactivity. Moreover, variability within some other receptors like GPVI, PECAM, PEAR1, and CD148 was analyzed only in single studies. Conclusions: Src family kinases are one of the most important signal transmitters in platelets. Some receptors have well documented interactions with SFKs, while other have not been examined in humans or data about its association originated from single studies. Further studies are necessary to confirm the findings and reduce falsepositive associations.

Background: Transcatheter aortic valve implantation (TAVI) is an increasingly common treatment of symptomatic severe aortic valve stenosis (AS). Thus, it is reasonable to carefully investigate the impact of individual clinical factors on outcomes after TAVI. Objectives: We aimed to investigate the impact of the previous cerebro-vascular events (CVEs) on outcomes of patients with severe AS undergoing TAVI. Methods: A total of 148 consecutive patients scheduled for TAVI were included and stratified as with and without a history of CVEs (stroke or transient ischemic attack). Frailty features were also assessed. The primary endpoint was a 12-month all-cause mortality. Results: Seventeen (11.5%) patients had a history of CVEs (the CVE group). At 30 days and 12 months, all-cause mortality was higher in the CVE group [30-day: 5 (29.4%) vs. 7 (5.3%); p=0.005; 12-month: 9 (52.9%) vs. 13 (9.9%); p=0.001]. Similarly, at the longest available follow-up, mortality was higher in the CVE group [10 (58.8%) vs. 23 (17.6%); p=0.001]. Similar rates of other complications after TAVI were noted, apart from inhospital acute kidney injury (AKI) grade 3 [3 (17.6%) vs. 5 (3.8%); p=0.049] and blood transfusions [9 (52.9%) vs. 35 (26.7%); p=0.026]. Results of 5MWT and Katz index assessment indicated a greater level of frailty in the CVE group. There were no differences in subsequent events including CVEs, bleeding, myocardial infarction, and new-onset of atrial fibrillation (AF) at 12 months between the groups. Conclusion: We showed that a history of CVEs in patients with severe AS undergoing TAVI is associated with a higher long-term mortality.