Nanotechnology was well developed during past decades and implemented in a broad range of industrial applications, which led to an inevitable release of nanomaterials into the environment and ecosystem. Silver nanoparticles (AgNPs) are one of the most commonly used nanomaterials in various fields, especially in the agricultural sector. Plants are the basic component of the ecosystem and the most important source of food for mankind; therefore, understanding the impacts of AgNPs on plant growth and development is crucial for the evaluation of potential environmental risks on food safety and human health imposed by AgNPs. The present review summarizes uptake, translocation, and accumulation of AgNPs in plants, and exemplifies the phytotoxicity of AgNPs on plants at morphological, physiological, cellular, and molecular levels. It also focuses on the current understanding of phytotoxicity mechanisms via which AgNPs exert their toxicity on plants. In addition, the tolerance mechanisms underlying survival strategy that plants adopt to cope with adverse effects of AgNPs are discussed.

New chemotherapeutic compounds against multidrug-resistant Mycobacterium tuberculosis (Mtb) are urgently needed to combat drug resistance in tuberculosis (TB). We have identified and characterized the indolcarboxamides as a new class of antitubercular bactericidal agent. Genetic and lipid profiling studies identified the likely molecular target of indolcarboxamides as MmpL3, a transporter of trehalose monomycolate that is essential for mycobacterial cell wall biosynthesis. Two lead candidates, NITD-304 and NITD-349, showed potent activity against both drug-sensitive and multidrug-resistant clinical isolates of Mtb. Promising pharmacokinetic profiles of both compounds after oral dosing in several species enabled further evaluation for efficacy and safety. NITD-304 and NITD-349 were efficacious in treating both acute and chronic Mtb infections in mouse efficacy models. Furthermore, dosing of NITD-304 and NITD-349 for 2 weeks in exploratory rat toxicology studies revealed a promising safety margin. Finally, neither compound inhibited the activity of major cytochrome P-450 enzymes or the hERG (human ether-a-go-go related gene) channel. These results suggest that NITD-304 and NITD-349 should undergo further development as a potential treatment for multidrug-resistant TB.

Prostate cancer is the most common cancer in men. Advanced prostate cancer spreading beyond the gland is incurable. Identifying factors that regulate the spread of tumor into the regional nodes and distant sites would guide the development of novel diagnostic, prognostic, and therapeutic targets. The aim of our study was to examine the expression and biological role of EphB4 in prostate cancer. EphB4 mRNA is expressed in 64 of 72 (89%) prostate tumor tissues assessed. EphB4 protein expression is found in the majority (41 of 62, 66%) of tumors, and 3 of 20 (15%) normal prostate tissues. Little or no expression was observed in benign prostate epithelial cell line, but EphB4 was expressed in all prostate cancer cell lines to varying degrees. EphB4 protein levels are high in the PC3 prostate cancer cell line and several folds higher in a metastatic clone of PC3 (PC3M) where overexpression was accompanied by EphB4 gene amplification. EphB4 expression is induced by loss of PTEN, p53, and induced by epidermal growth factor/epidermal growth factor receptor and insulinlike growth factor-I/insulin-like growth factor-IR. Knockdown of the EphB4 protein using EphB4 short interfering RNA or antisense oligodeoxynucleotide significantly inhibits cell growth/viability, migration, and invasion, and induces apoptosis in prostate cancer cell lines. Antisense oligodeoxynucleotide targeting EphB4 in vivo showed antitumor activity in murine human tumor xenograft model. These data show a role for EphB4 in prostate cancer and provide a rationale to study EphB4 for diagnostic, prognostic, and therapeutic applications. (Cancer Res 2005; 65(11): 4623-32)

Growth Regulated Oncogene-a (GRO-a) is an autocrine growth factor in melanoma and is a member of the C-X-C family of chemokines which promote chemotaxis of granulocytes and endothelia through binding to CXC Receptor 2. We found previously that variants of murine squamous cell carcinoma PAM 212 which grow and metastasize more rapidly in vivo constitutively express increased levels of murine GRO-a, designated mGRO-a, or KC. We have examined the possible role of mGRO-a expression in malignant progression of squamous cell carcinoma PAM 212 in homologous BALB/c and BALB CXC Receptor-2 de®cient mice. Transfection of the PAM 212 cell line which exhibits low expression of GRO-a and malignant potential with a pActin-KC vector encoding mGRO-a enabled isolation of PAM-KC expressing cell lines. These PAM-KC transfectants displayed an increased rate of growth and metastasis in BALB/c mice, similar to the highly malignant phenotype observed in spontaneously occurring metastatic variants. Furthermore, the PAM-KC tumors showed an increase in in®ltration of host leukocytes and CD31+ blood vessels, consistent with increased CXC chemokine activity. The increased growth of PAM-KC cells was attenuated in CXCR-2 de®cient mice, indicating that the increased growth was dependent in part upon host cells responsive to the CXC chemokine. Together, these results show that a CXC chemokine such as GRO-a can promote malignant growth of murine squamous cell carcinoma by a host CXCR-2 dependent pathway.