Overexpression of miR-21 promotes proliferation and reduces apoptosis in non-small cell lung cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To elucidate the regulatory mechanism underlying proliferation and anti-apoptosis in NSCLC by overexpression of miR-21.</p><p><b>METHODS</b>Real-time PCR was used to measure miR-21 abundance in non-small cell lung cancer (NSCLC) tumor samples and adjacent normal tissues, as well as NSCLC cell lines. Tumor suppressor genes as potential targets of miR-21 were predicted by sequence analysis. Luciferase assay and Western blot were used to assess the regulatory effect. The effect on A549 cell viability and apoptosis by miR-21-induced gene repression was tested by trypan-blue exclusion and flow cytometry.</p><p><b>RESULTS</b>miR-21 expression was 2.24-fold higher in the NSCLC tumor samples and 3.06-fold higher in the A549 cells than that in the adjacent normal tissues. Sequence prediction and gene expression regulation assays showed that miR-21 could reversely regulate the expression of PDCD4 (P < 0.01). Suppression of miR-21 expression is associated with an elevation of Pdcd4, resulting in a significant reduction of proliferation and the apoptosis rate (2.6%) was increased to 10.9%. Moreover, the anti-proliferation and pro-apoptotic effect by miR-21 suppression could be reversed by PDCD4 knock down.</p><p><b>CONCLUSION</b>Suppression of the tumor suppressor PDCD4 expression may be one of the important regulatory pathways of the miR-21-mediated cell proliferation and decrease of apoptosis in non-small cell lung cancer.</p>

In-vivo targeted imaging of hepatocellular carcinoma in nude mice using quantum dot probes / 中华病理学杂志

<p><b>OBJECTIVE</b>To explore in-vivo targeted imaging techniques for liver cancer detection using quantum dots (QDs) labeled probes in a nude mouse model of human hepatocellular carcinoma.</p><p><b>METHODS</b>Mercaptoacetic acid (MAA) modified QDs were linked to mouse-anti-human alpha-fetoprotein (AFP) monoclonal antibody to form water soluble QD-AFP-Ab probes, which were validated by spectra analyses and transmission electron microscope. The probes were firstly used to detect AFP antigen in human hepatocellular carcinoma cell line HCCLM6 in-vitro by one-step immunofluorescence method. In-vivo tumor xenografts and lung metastases models were then established by inoculation of HCCLM6 cells subcutaneously and into the tail vein of nude mice, respectively. QD-AFP-Ab probes were injected into the tail vein of the tumor bearing mice for live animal fluorescence imaging. Spectra of tumor and normal tissue were analyzed under illumination of Ti: sapphire laser. Serum levels of alanine amino transferase, aspartate amino transferase, blood urea nitrogen and creatinine were determined by conventional biochemical analysis. The liver, spleen, lungs, kidneys, heart and brain of the experimental nude mice were investigated for nonspecific uptake of the probes by confocal microscope.</p><p><b>RESULTS</b>The QD-AFP-Ab probes had broad excitation spectra and high fluorescence intensity. They could specifically and efficiently recognize AFP antigen in hepatocellular carcinoma cells. Tumor targeting imaging using these probes were successful without any acute toxicity to the experimental animals. Spectra analysis showed that the probes per field were lower in the centre than the periphery of the tumor. Non-specific uptake of QD-AFP-Ab probes occurred mainly in the liver, spleen and lungs.</p><p><b>CONCLUSIONS</b>QD-AFP-Ab probes have good optical properties and biocompatibility for in-vivo targeted imaging of hepatocellular carcinoma. Such approach promises to be highly desirable for molecular targeted research of liver cancer.</p>