Antibody–drug conjugates (ADCs) for cancer therapy: Strategies,challenges, and successes

Targeted delivery of therapeutic molecules into cancer cells is considered as a promising strategy to tackle cancer. Antibody–drug conjugates (ADCs), in which a monoclonal antibody (mAb) is conjugated to biologically active drugs through chemical linkers, have emerged as a promising class of anticancer treatment agents, being one of the fastest growing fields in cancer therapy. The failure of early ADCs led researchers to explore strategies to develop more effective and improved ADCs with lower levels of unconjugated mAbs and more-stable linkers between the drug and the antibody, which show improved pharmacokinetic properties, therapeutic indexes, and safety profiles. Such improvements resulted in the US Food and Drug Administration approvals of brentuximab vedotin, trastuzumab emtansine, and, more recently, inotuzumab ozogamicin. In addition, recent clinical outcomes have sparked additional interest, which leads to the dramatically increased number of ADCs in clinical development. The present review explores ADCs, their main characteristics, and new research developments, as well as discusses strategies for the selection of the most appropriate target antigens, mAbs, cytotoxic drugs, linkers, and conjugation chemistries.     

Synergistic effect of coronatine and sorbitol on artemisinin production in cell suspension culture of Artemisia annua L. cv. Anamed

Plant Cell, Tissue and Organ Culture (PCTOC) - Artemisinin is an efficient anti-malarial drug and it possesses biological activity against a wide range of cancers. The combined application of two...     

Targeted therapies in pancreatic cancer: Promises and failures

Pancreatic ductal adenocarcinoma (PDAC) is an incidence rate nearly equal to its mortality rate. The poor prognosis of the disease can be explained by the absence of effective biomarkers for screening and early detection, together with the aggressive behavior and resistance to the currently available chemotherapy. The therapeutic failure can also be attributed to the inter-/intratumor genetic heterogeneity and the abundance of tumor stroma that occupies the majority of the tumor mass. Gemcitabine is used in the treatment of PDAC; however, the response rate is less than 12%. A recent phase III trial revealed that the combination of oxaliplatin, irinotecan, fluorouracil, and leucovorin could be an option for the treatment of metastatic PDAC patients with good performance status, although these approaches can result in high toxicity level. Further investigations are required to develop innovative anticancer agents that either improve gemcitabine activity, within novel combinatorial approaches or acts with a better efficacy than gemcitabine. The aim of the current review is to give an overview of preclinical and clinical studies targeting key dysregulated signaling pathways in PDAC.     

Improved non-viral transfection of glial and adult neural stem cell lines and of primary astrocytes by combining agents with complementary modes of action

BACKGROUND: Rational design of gene vectors for therapeutic applications requires understanding of transfection mechanisms. In this study, multiple transfection assays revealed complementary mechanisms between two commonly used transfection agents. This finding was then exploited to produce improved transfection outcomes. METHODS AND RESULTS: Rat C6 glial cells, adult rat hippocampal progenitor cells and primary astrocytes were transfected using Lipofectamine (LA) or polyethylenimine (PEI), in vitro. Although LA- and PEI-transfected populations expressed the same total level of transgene product, LA transfected considerably more cells than PEI (approximately 20 vs. 14%). A fluorescently labelled plasmid and time-course analysis, involving both flow cytometry and confocal microscopy, were used to explain this apparent discrepancy. Results showed that LA delivered more plasmid DNA to the cytoplasm and achieved transgene expression in more cells than PEI. In contrast, PEI transfected fewer cells but, on average, produced more transgene product per transfected cell. CONCLUSIONS: A comparative transfection model was developed to explain these different characteristics. According to this model, transfection is a multistage process with different transfection agents exerting their primary effect at different stages in this process. This model forecast that it should be possible to prepare a chimeric complex with a transfection efficiency that exceeded that achievable with Lipofectamine or polyethylenimine alone. This prediction was tested and shown to hold for glioma cells, primary astrocytes, and adult neural stems cells.     

A product inhibition study on adenosine deaminase by spectroscopy and calorimetry

Kinetic and thermodynamic studies have been made on the effect of the inosine product on the activity of adenosine deaminase in a 50 mM sodium phosphate buffer, pH 7.5, at 27 degrees C using UV spectrophotometry and isothermal titration calorimetry (ITC). A competitive inhibition was observed for inosine as a product of the enzymatic reaction. A graphical-fitting method was used for determination of the binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to 140 microM by the microcalorimetry method, which agrees well with the value of 143 microM for the inhibition constant that was obtained from the spectroscopy method     

Molecular Expression of Some Oncogenes and Predisposing Behaviors Contributing to the Aggressiveness of Prostate Cancer

Background:Prostate cancer is the second most common cancer in men in Iran. It can be treated in the early stages of the disease; therefore, early diagnosis can be lifesaving. The aim of this study was to investigate the molecular expression of some oncogenes and predisposing behaviors contributing to the aggressiveness of prostate cancer.Methods:In this case-control study, prostate cancer specimens were collected from both patients and healthy volunteers. Several factors such as age, family history, smoking, and stage of the disease, were investigated based on the criteria of this study. Real-time PCR was used to measure the expression of four oncogenes. Statistical analysis of our data was carried out using SPSS software version 22.Results:The X² test showed that there was a difference in the incidence of prostate cancer in different age groups (X²= 9.30; p= 0.026). Although data analysis by the X² test showed that family history had a significant effect on prostate cancer (X²= 14.43; p= 0.001), smoking did not show a significant effect on the incidence of this disorder (X²= 4.67; p= 0.097). The T2N1M0 stage is the most common form of prostate cancer in patients with family history of prostate cancer and the habit of smoking. Also, the expression of KRAS1P, GLB1L2, SChLAP1 and PACSIN3 oncogenes reduced in prostate cancer samples compared to the control group.Conclusion:Overall, functional interpretation of gene expression in the prostate tissue can affect tumor progression. Yet, further practical studies are required to reveal the accurate underlying mechanisms.Key Words: Age, Family History, Oncogenes, Prostate Cancer, Smoking     

First record and redescription of the terrestrial isopod Hemilepistoides messerianus Borutzky, 1945 (Isopoda,Oniscidea) from Iran

In the present study, Hemilepistoides messerianus Borutzky, 1945 is reported from Iran for the first time. This species is redescribed and diagnostic characters of both males and females are illustrated. This species is characterized by the tuberculation of all parts of the dorsal surface of the body and the male pleopod endopodite I with a triangular lobe at apex. A map with the distribution of species is presented.     

Identification of cytoplasmic and membrane-associated complexes in human embryonic stem cells using blue native PAGE

Human embryonic stem cells (hESCs) have great potential for use in developmental biology studies, functional genomics applications, drug screening, and regenerative medicine. A detailed understanding of the molecular mechanisms that are responsible for maintaining the undifferentiated and pluripotent nature of hESCs is essential for their effective therapeutic application. It has become evident that many complex cellular processes are carried out by assemblies of protein molecules (protein complexes). Blue native polyacrylamide gel electrophoresis (BN-PAGE) has been used to separate protein complexes from whole cell lysates. Using BN-PAGE, we resolved cytoplasmic and membrane-associated complexes from hESCs and characterised their composition, stoichiometry, and dynamics by denaturing SDS-PAGE. The reliability of the fractionation was examined by western blot analysis of membrane and cytosolic markers. MALDI TOF/TOF mass spectrometry identified 119 cytosolic and 69 membrane proteins from the BN-PAGE proteome maps. Potential protein complexes were validated by computational prediction of possible protein-protein interactions using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database. Based on BN-PAGE gels and validation by databases, 82 heteromultimeric and 47 homomultimeric protein complexes have been found in hESCs. Resolving some of the protein complexes provided insight into the function of previously uncharacterised complexes in hESCs.     

Proteomic analysis of the Mexican lime tree response to "Candidatus Phytoplasma aurantifolia" infection

"Candidatus Phytoplasma aurantifolia" is the causative agent of witches' broom disease in the Mexican lime tree (Citrus aurantifolia L.), and is responsible for major tree losses in Southern Iran and Oman. The pathogen is strictly biotrophic, and, therefore, completely dependent on living host cells for its survival. The molecular basis of compatibility and disease development in this system is poorly understood. We applied a proteomics approach to analyse gene expression in Mexican limes infected with "Ca. Phytoplasma aurantifolia". Leaf samples were collected from healthy and infected plants and were analysed using 2-DE coupled with MS. Among 800 leaf proteins that were detected reproducibly in eight biological replicates of healthy and eight biological replicates of infected plants, 55 showed a significant response to the disease. MS resulted in identification of 39 regulated proteins, which included proteins that were involved in oxidative stress defence, photosynthesis, metabolism, and the stress response. Our results provide the first proteomic view of the molecular basis of the infection process and identify genes that could help inhibit the effects of the pathogen.     

Bone medullary arterioles from ovariectomized rats have smaller baseline diameters but normal eNOS expression and NO-mediated dilation

This study was designed to test the hypothesis that endogenous estrogens decrease the expression of endothelial nitric oxide synthase (eNOS) in resistance-size bone arterioles, thereby reducing endothelium-dependent vasodilator function. Sexually mature female rats were ovariectomized to reduce endogenous estrogens. Age-matched female rats served as controls. Seven to ten days after ovariectomy, bone marrow tissue was collected from the femoral canal. Immuno-histochemistry was performed to detect expression of estrogen receptors, alpha and beta and eNOS. eNOS protein content in medullary bone arterioles was compared using Western blot analysis. Endothelial cell function was assessed by quantitating the dilation of isolated, pressurized bone arterioles in response to acetylcholine. The results indicate that the endothelium of bone arterioles from ovariectomized and control rats express ER-alpha, ER-beta and eNOS. eNOS protein content in the two groups of arterioles did not differ. However, the baseline diameter of arterioles from ovariectomized rats (63+/-4 microm) was significantly smaller than the diameter of arterioles from control rats (75+/-3 microm, p<0.05). The two groups of arterioles dilated equally in response to acetylcholine. L-NAME, an inhibitor of eNOS, almost completely abolished the dilator responses to acetylcholine, but not to sodium nitroprusside. L-Arginine restored acetylcholine-induced dilation after L-NAME treatment. Thus, arteriole dilation to acetylcholine appears to be mediated almost exclusively by NO. The smaller diameter of arterioles from ovariectomized rats suggests that endogenous estrogens exert a significant dilator influence on bone arterioles. However, the dilator influence does not appear to be mediated by an increase in eNOS expression or enhanced NO-dependent vasodilation. These results indicate that estrogens do not decrease eNOS expression or diminish NO-mediated dilation of bone medullary arterioles.