Selenium (Se) acts as an essential trace element in the human body due to its unique biological functions, particularly in the oxidation-reduction system. Although several clinical trials indicated no significant benefit of Se in preventing cancer, researchers reported that some Se species exhibit superior anticancer properties. Therefore, a reassessment of the status of Se and Se compounds is necessary in order to provide clearer insights into the potentiality of Se in cancer prevention and therapy. In this review, we organize relevant forms of Se species based on the three main categories of Se—inorganic, organic, and Se-containing nanoparticles (SeNPs)—and overview their potential functions and applications in oncology. Here, we specifically focus on the SeNPs as they have tremendous potential in oncology and other fields. In general, to make better use of Se compounds in cancer prevention and therapy, extensive further study is still required to understand the underlying mechanisms of the Se compounds.

Conventional chemotherapy is still an important option of cancer treatment, but it has poor cell selectivity, severe side effects, and drug resistance. Utilizing nanoparticles (NPs) to improve the therapeutic effect of chemotherapeutic drugs has been highlighted in recent years. Nanotechnology dramatically changed the face of oncology by high loading capacity, less toxicity, targeted delivery of drugs, increased uptake to target sites, and optimized pharmacokinetic patterns of traditional drugs. At present, research is being envisaged in the field of novel nano-pharmaceutical design, such as liposome, polymer NPs, bio-NPs, and inorganic NPs, so as to make chemotherapy effective and long-lasting. Till now, a number of studies have been conducted using a wide range of nanocarriers for the treatment of solid tumors including lung, breast, pancreas, brain, and liver. To provide a reference for the further application of chemodrug-loaded nanoformulations, this review gives an overview of the recent development of nanocarriers, and the updated status of their use in the treatment of several solid tumors.

Arsenite is well documented as a chemotherapeutic agent capable of inducing cell death. However, the cellular response at the molecular level has not been studied extensively. In the present study, we provide for the first time a proteomic analysis of rat LECs (lung epithelial cells) treated with arsenite, with the aim of identifying defence proteins, probably expressed to protect the cells during the course of arsenic-induced apoptosis. Comparative proteome analysis was conducted on LECs and LECs treated with 40 μM arsenite to identify global changes in their protein expression profiles. Over 1000 protein spots were separated by two-dimensional electrophoresis and visualized by silver staining. Seven proteins changed expression levels significantly and were identified by matrix-assisted laser-desorption ionization–time-of-flight mass spectrometry and database searching. The proteins up-regulated were mostly HSPs (heat-shock proteins) and antioxidative stress proteins, including HSP70, aldose reductase, haem oxygenase-1, HSP27, ferritin light chain and αB-crystallin. The glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase was down-regulated. Pretreatment with the thiol antioxidants glutathione or N-acetylcysteine before arsenite insult effectively abrogated the induction of these defence proteins and sustained cell viability, whereas antioxidants were protective only at earlier time points if they were added to cells after arsenite. Taken together, our results demonstrate that high levels of arsenite cause oxidative stress-induced apoptosis.

Cyclin-dependent kinase (cdk)-3, a member of the cdk family of kinases, plays a critical role in cell cycle regulation and is involved in G₀-G₁ and G₁-S cell cycle transitions. However, the role of cdk3 in cell proliferation, as well as cell transformation, is not yet clearly understood. Here, we report that the protein expression level of cdk3 is higher in human cancer cell lines and human glioblastoma tissue compared with normal brain tissue. Furthermore, we found that cdk3 phosphorylates activating transcription factor 1 (ATF1) at serine 63 and enhances the transactivation and transcriptional activities of ATF1. Results also indicated that siRNA directed against cdk3 (si-cdk3) suppresses ATF1 activity, resulting in inhibition of proliferation and growth of human glioblastoma T98G cells in soft agar. Importantly, we showed that cdk3 enhances epidermal growth factor–induced transformation of JB6 Cl41 cells and si-cdk3 suppresses Ras^G12V/cdk3/ATF1–induced foci formation in NIH3T3 cells. These results clearly showed that the cdk3-ATF1 signaling axis is critical for cell proliferation and transformation. [Cancer Res 2008;68(18):7650–60]