[Rapid detection of extrinsic harmful contaminants using quantum dots-coated probes and their application prospects in traditional Chinese medicine].

The contamination of extrinsic harmful contaminants including mycotoxins, heavy metals and pesticides, etc, brings serious risks to traditional Chinese medicines (TCMs), further to human health. Due to their unique photoluminescence, chemiluminescence, electrochemical and electrochemiluminescence properties, semiconductor quantum dots (QDs) nanoparticles are widely used to immobilize bioprobes and biosensors, etc. In this review, the luminescence characteristics and specific ligands of QDs probles which are used to determine contaminants were summed up. Then, the applications of QDs-coated novel probes in the determination of mycotoxins, heavy metals and pesticides were discussed in detail. In addition, the contamination levels and characteristics of extrinsic harmful residues in TCMs were investigated. Further, the maximum levels of those contaminants in TCMs were compared with those set by various countries. Finally, the future development trends and problems of QDs-coated probes in the determination of those extrinsic residues in TCMs were prospected.

Simultaneous inhibition of focal adhesion kinase and SRC enhances detachment and apoptosis in colon cancer cell lines.

Focal adhesion kinase (FAK) and Src have been shown to be overexpressed in colon cancer. We have studied the role of these two kinases in resistance to apoptosis. Adenovirus-containing FAK-CD (Ad-FAK-CD), a dominant-negative, COOH-terminal portion of FAK, was used to inhibit FAK and cause apoptosis. Colon cancer cell lines were more resistant to Ad-FAK-CD-induced detachment and apoptosis than the breast cancer cell line, BT474. Colon cancer cell lines overexpressed highly active Src and FAK. Ad-FAK-CD-induced apoptosis was significantly increased by PP2, an inhibitor of Src family kinases. Activation of caspase-3, down-regulation of FAK, and Src and AKT activities were demonstrated in Ad-FAK-CD + PP2-treated colon cancer cells undergoing apoptosis. The results suggest that FAK and Src are both important survival factors, playing a role in protecting colon cancer cell lines from Ad-FAK-CD-induced apoptosis. Dual inhibition of these kinases may be important for therapies designed to enhance the apoptosis in colon cancers.

Overexpression of the receptor tyrosine kinase Tie-1 intracellular domain in breast cancer.

OBJECTIVE: Tyrosine kinase with immunoglobulin and epidermal growth factor homology domains (Tie-1) is a receptor tyrosine kinase that regulates angiogenesis and antiapoptotic survival signaling. Tie-1 expression is generally associated with endothelial cells and neovascularization. We previously identified Tie-1 in human breast tumor samples using a PCR-based screen for protein kinases expressed in breast tumors. The purpose of this study was to determine the cell types expressing Tie-1, whether Tie-1 is expressed in tumor cells, and to examine the regulation of Tie-1 in breast cancer. METHODS: Tie-1 expression was analyzed by Western blot and immunohistochemistry using an antibody to the carboxy terminus of Tie-1. Tie-1 expression was determined in a variety of cancer cell lines, clinical breast and colon tumor samples, and in corresponding benign tissue from the same patient. Tie-1 expression and distribution in breast tumors was scored by immunohistochemistry. RESULTS: Tie-1 was overexpressed in 14/23 breast tumors compared with 0/9 corresponding normal tissues from the same patients. Immunohistochemistry revealed that Tie-1 was overexpressed in epithelial breast cancer cells and ductal carcinoma in situ. In all breast tumor samples, Tie-1 was expressed as a truncated 40- to 43-kD doublet consisting of the intracellular portion of the protein, which contains the tyrosine kinase catalytic domain. The 40- to 43-kD Tie-1 doublet was expressed in a broad variety of cell lines. CONCLUSIONS: We have shown that breast cancer cells overexpress a cleaved form of the Tie-1 protein. Our results implicate the intracellular domain of Tie-1, which includes the catalytic kinase domain, in breast cancer progression.