Current Drug Discovery Technologies (v.12, #1)

Meet Our Editor: by Vladimir Torchilin (1-2).

Cancer is one of the leading causes of death in the United States along with heart disease. The hallmark of cancer treatment has been conventional chemotherapy. Chemotherapeutic drugs are designed to target not only rapidly dividing cells, such as cancer cells, but also certain normal cells, such as intestinal epithelium. Over the past several years, a new generation of cancer treatment has come to the forefront, i.e, targeted cancer therapies. Like conventional chemotherapy, targeted cancer therapies use pharmacological agents that inhibit growth, increase cell death and restrict the spread of cancer. As the name suggests, targeted therapies interfere with specific proteins involved in tumorigenesis. Rather than using broad base cancer treatments, focusing on specific molecular changes which are unique to a particular cancer, targeted cancer therapies may be more therapeutically beneficial for many cancer types, including lung, colorectal, breast, lymphoma and leukemia. Moreover, recent advances have made it possible to analyze and tailor treatments to an individual patient's tumor. There are three main types of targeted cancer therapies; 1) monoclonal antibodies, 2) small molecule inhibitors and 3) immunotoxins. This review will discuss these three classes of targeted therapies in detail, as well as the biology behind targeted cancer therapies.

Hair Growth: Focus on Herbal Therapeutic Agent by Satish Patel, Vikas Sharma, Nagendra S. Chauhan, Mayank Thakur, V.K. Dixit (21-42).
This review presents an overview on plants identified to possess hair growth activity in various ethno-botanical studies and surveys of tradition medicinal plants. It also highlights the developments in hair rejuvenation strategies from 1926 till-date and reviews the potential of herbal drugs as safer and effective alternatives. There are various causes for hair loss and the phenomenon is still not fully understood. The treatments offered include both natural or synthetic products to treat the condition of hair loss (alopecia), nonetheless natural products are continuously gaining popularity mainly due to their fewer side effects and better formulation strategies for natural product extracts. Plants have been widely used for hair growth promotion since ancient times as reported in Ayurveda, Chinese and Unani systems of medicine. This review covers information about different herbs and herbal formulation that are believed to be able to reduce the rate of hair loss and at the same time stimulate new hair growth. A focus is placed on their mechanism of action and the review also covers various isolated phytoconstituents possessing hair growth promoting effect.

Repulsive Apoptosis During Exposure of Mesencephalic Neural Stem Cells to Silver Nanoparticles in a Neurosphere Assay In Vitro by Masami Ishido, Eiko Shimaya, Rumiko Usu, Yoshika Kurokawa, Seishiro Hirano (43-51).
Neurodevelopmental toxicity of silver nanoparticles (AgNPs) remains largely unknown. In this study, we applied a neurosphere assay for neurodevelopmental effects of AgNPs. The neural stem cells were isolated from rat mesencephalon. They were cultured as a sphere. In an assay with coated plates, cells appeared by anchoraging on the dish and then started to migrate along the radial axis from the neurosphere. AgNPs inhibited cell migration in a dose-dependent manner. There was a linear correlation between the inhibition of migration and the logarithm of the particle concentration (1.25–10 μg/ml); the half-maximal inhibitory concentration was 0.41 μg/ml for 16-h exposure. Preceding migrated cells were retarded and/or collapsed by exposure to AgNPs: lower doses of AgNPs (0.31–1.2 μg/ml) caused a 42% retardation for 48 h, while higher doses of AgNPs (2.5–10 μg/ml) collasped migrating cells. Furthermore, collapsed cells were TUNEL-positive and showed a defect in the mitochondrial membrane potential. Thus, we showed the neurodevelopmental toxicity of AgNPs using an in vitro neurosphere assay system.

State of the Art Detection System for Curcumin Analog by Angelene Hannah Jebarani, Arul Prakash Francis, Thiyagarajan Devasena (52-58).
In spite of the need for sensing bisdemethoxycurcumin analog (BDMCA), there is no detection system available so far. For the first time, we have demonstrated a sensing system for detecting BDMCA. Initially, chitosan thin films of three different molecular weights (low, average, high) were tested for the conductivity. The high molecular weight chitosan film was found to produce higher conductance and hence, used as the substrate. Addition of BDMCA to this substrate induced a significant conductance change (as revealed by impedance analyzer), making the detection system qualitative. Addition of increasing concentrations of BDMCA produced significantly concomitant increase in the conductivity (observed as decrease in current density as revealed by cyclic voltammetry) making the sensor quantitative. Our results show that this chitosan based electrochemical sensing system can be used for the rapid quantitative detection of BDMCA. As there is no BDMCA sensor available so far, this type of detection is very essential to monitor the pharmacokinetic behavior, the therapeutic dosage, bioavailability and related toxicity of BDMCA in different formulations and samples.

In Vitro Protective Potentials of Annona muricata Leaf Extracts Against Sodium Arsenite-induced Toxicity by Vazhappilly Cijo George, Devanga Ragupathi Naveen Kumar, Palamadai Krishnan Suresh, Rangasamy Ashok Kumar (59-63).
Sodium arsenite (NaAsO2) is a metalloid which is present widely in the environment and its chronic exposure can contribute to the induction of oxidative stress, resulting in disturbances in various metabolic functions including liver cell death. Hence, there is a need to develop drugs from natural sources, which can reduce arsenic toxicity. While there have been reports regarding the antioxidant and protective potentials of Annona muricataleaf extracts, our study is the first ofits kind to extend these findings by specifically evaluating its ability to render protection against sodium arsenite (NaAsO2) induced toxicity (10 μM) in WRL-68 (human hepatic cells) and human erythrocytes by employing XTT and haemolysis inhibition assays respectively. The methanolic extract exhibited higher activity than the aqueous extract in both assays. The results showed a dose-dependent decrease in arsenic toxicity in both WRL-68 cells and erythrocytes, suggesting the protective nature of Annona muricatato mitigate arsenic toxicity. Hence the bioactive extracts can further be scrutinized for the identification and characterization of their principal contributors.