PLK1 promotes epithelial-mesenchymal transition and metastasis of gastric carcinoma cells.

Cancer cell epithelial-mesenchymal transition (EMT) is the crucial event for cancer progression and plays a vital role in the metastasis of cancer cells. Activation of Polo-like kinase 1 (PLK1) signaling has been implicated as the critical event in several tumor metastasis and EMT, however, whether PLK1 participates in gastric carcinoma metastasis and EMT still remains unclear. For this study, we elucidated the potential physiological function of PLK1 in the metastasis of gastric tumors, as well its distinct role in cells EMT and subsequently determined the mechanism involved in PLK1 regulated. Immunoblotting assay and Oncomine data mining analysis indicated that PLK1 expression was highly up-regulated in gastric carcinoma. Kaplan-Meier survival analysis for the relationship between survival outcomes and PLK1 expression in gastric carcinoma was performed with an online Kaplan-Meier plotter (http://kmplot.com/analysis/). Over-expression of PLK1 in gastric cancer cells SGC-7901 and MKN-28 significantly promoted cells profound morphological changes and enhanced metastatic ability of tumor cells. On the contrary, silencing of PLK1 induced mesenchymal epithelial transition (MET)-like morphological and inhibited the metastatic process. Furthermore, we found that the metastatic characters promoting effects of PLK1 in gastric carcinoma was related to the activation of protein kinase B (AKT). Our mechanistic investigations revealed that AKT inhibition reversed PLK1-induced EMT, blocked gastric carcinoma cells invasiveness and metastasis. Additionally, over-expression of AKT promoted the migratory and invasion ability of the two cell lines, which was disrupted by PLK1 down-regulation. To conclude, our findings demonstrate that PLK1 accelerates the metastasis and epithelial-mesenchyme transition of gastric cancer cells through regulating the AKT pathway.

[Advances in copepod resting egg ecology in estuarine and coastal waters].

Copepods are the key group in aquatic ecosystems, and play an important role in energy flow, the cycle of materials and information transfer. This paper summarized the distribution and composition of the copepods that spawn resting eggs in the estuarine and coastal marine areas. It also reviewed the survival time, hatching rates, abundance of resting eggs in the sediments, and the potential recruitment into the plankton population as correlated with environmental factors. The prospects of copepod resting egg ecology were also proposed in order to provide new ideas for future research.

[Increased coronin-1C expression is related to hepatocellular carcinoma invasion and metastasis].

OBJECTIVE: To search for hepatocellular carcinoma (HCC) invasion related biomarkers using the cell membrane proteomics approaches, and to validate the markers using experimental and clinical specimens. METHODS: The HCCLM9 and MHCC97L cells with a similar genetic background and remarkably different metastasis behaviors were used for comparative membrane proteome profiling using sodium dodecyl sulfate polyacrylamide gel electrophoresis and electrospray ionization mass spectrometry technologies. Candidate protein makers were further validated by western blot on cells, immunohistochemistry (IHC) on animal tumor tissues, and tissue micro-array on clinical specimens. RESULTS: The membrane proteins of MHCC97L and HCCLM9 cells were compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis analyses. 14 proteins were identified by ESI-MS/MS among the differential bands. Coronin-1C was overexpressed in HCCLM9 (7.31+/-0.73) versus MHCC97L (2.84+/-0.99) validated by western blot. Elevated coronin-1C expression was observed in liver cancer tissues of HCCLM9 nude mice. IHC study in 115 human HCC specimens demonstrated that patients with higher coronin-1C expression had more advanced stage. CONCLUSION: The study suggests that coronin-1C could be a potential molecule to predict HCC invasive behavior.

Coronin-1C is a novel biomarker for hepatocellular carcinoma invasive progression identified by proteomics analysis and clinical validation.

BACKGROUND: To better search for potential markers for hepatocellular carcinoma (HCC) invasion and metastasis, proteomic approach was applied to identify potential metastasis biomarkers associated with HCC. METHODS: Membrane proteins were extracted from MHCC97L and HCCLM9 cells, with a similar genetic background and remarkably different metastasis potential, and compared by SDS-PAGE and identified by ESI-MS/MS. The results were further validated by western blot analysis, immunohistochemistry (IHC) of tumor tissues from HCCLM9- and MHCC97L-nude mice, and clinical specimens. RESULTS: Membrane proteins were extracted from MHCC97L and HCCLM9 cell and compared by SDS-PAGE analyses. A total of 14 differentially expressed proteins were identified by ESI-MS/MS. Coronin-1C, a promising candidate, was found to be overexpressed in HCCLM9 cells as compared with MHCC97L cells, and validated by western blot and IHC from both nude mice tumor tissues and clinical specimens. Coronin-1C level showed an abrupt upsurge when pulmonary metastasis occurred. Increasing coronin-1C expression was found in liver cancer tissues of HCCLM9-nude mice with spontaneous pulmonary metastasis. IHC study on human HCC specimens revealed that more patients in the higher coronin-1C group had overt larger tumor and more advanced stage. CONCLUSIONS: Coronin-1C could be a candidate biomarker to predict HCC invasive behavior.

Quantum dots-based immunofluorescence technology for the quantitative determination of HER2 expression in breast cancer.

HER2 detection is important for breast cancer (BC) treatment and prognosis, but the detection methods currently used have some disadvantages. Quantum dots (QDs)-based probes provide a potentially important new method for HER2 detection in clinical practice. This potential is examined in this paper. A QDs HER2 probe kit and QDs image acquisition and analysis software were developed and applied to 94 clinical samples of BC. Compared to conventional immunohistochemistry techniques, this method provided a superior accurate and sensitive method for the detection of HER2 in clinical breast cancer diagnosis.

Evaluation of tumor markers biochip C12 system in the diagnosis of gastric cancer and the strategies for improvement: analysis of 100 cases.

BACKGROUND/AIMS: A C12 biochip system using 12 tumor markers has been developed in China for serum diagnosis of common cancers. This work is to evaluate this C12 system in the diagnosis of gastric cancer. METHODOLOGY: Sera from 100 gastric carcinoma patients were screened for 12 tumor markers including carcinoembryonic antigen, alpha-fetoprotein, carbohydrate antigen 19-9, carbohydrate antigen 242, cancer antigen 15-3, cancer antigen 125, prostate specific antigen, free-PSA, neuron-specific enolase, human chorionic gonagotropin-beta, human growth hormone, and ferritin, using the C12 biochip system. The most relevant tumor marker and the contribution of the tumor markers to the improvement of diagnosis were determined. RESULTS: The overall diagnostic rate of C12 biochip system was 37%, and 7.8%, 29.4%, 35.5% and 50%, respectively, for stages I, II, III and IV patients. The differences in diagnostic rates between stage I (7.8%) and stage IV (50%) reached statistical significance (chi-square test, Chi2=7.20, p<0.01). Among all the 12 markers, carbohydrate antigen 19-9 had the highest positive rate up to 23%, against which any form of combinations of 5 most relevant tumor markers (2, 3, 4 or 5 markers combined) could not significantly improve the diagnostic rate. CONCLUSIONS: The C12 biochip system has some value in the diagnosis of advanced stage gastric cancer, but less sensitive in early gastric cancer.

The biocompatibility of quantum dot probes used for the targeted imaging of hepatocellular carcinoma metastasis.

Semiconductor quantum dots (QDs) have several photo-physical advantages over organic dyes making them good markers in biomedical application. We used CdSe/ZnS QDs with maximum emission wavelength of 590nm (QD590) linked to alpha-fetoprotein (AFP) monoclonal antibody (Ab) to detect AFP in cytoplasm of human hepatocellular carcinoma (HCC) cell line HCCLM6. For the in vivo studies, we used QD-AFP-Ab probes for targeted imaging of human HCC xenograft growing in nude mice by injecting them into the tail vein. In addition, the cytotoxicity in vitro, the acute toxicity in vivo, the hemodynamics and tissue distribution of these probes were also investigated. The results in vitro and in vivo indicate that our QD-based probes have good stability, specificity and biocompatibility for ultrasensitive fluorescence imaging of molecular targets in our liver cancer model system.

Intraperitoneal chemotherapy with hydroxycamptothecin reduces peritoneal carcinomatosis: results of an experimental study.

PURPOSE: We studied the efficacy and safety of intraperitoneal chemotherapy with hydroxycamptothecin (HCPT) for the treatment of peritoneal carcinomatosis in animal model. METHODS: Highly metastatic human hepatocellular carcinoma (HCC) cell line HCCLM3 was injected into the peritoneal cavity of 30 nude mice to construct a model of intraperitoneal carcinomatosis, which were randomized into a treatment group and a control group of 15 mice in each group. The former received intraperitoneal injections of HCPT at the dose of 2 mg/kg body weight for 7 days every other week, on weeks 2, 4 and 6; and the latter received the same dose schedule treatment of 0.9% sodium chloride solution. The mice were observed for 8 weeks. Body weight changes, intraperitoneal carcinomatosis, hematological and biochemical parameters were evaluated. RESULTS: On day 56, 14 mice in the treatment group were still alive, compared against 5 in the control group, and the mean survival time was 55 +/- 1 days [95% confidence interval (CI) 54-57 days] versus 43 +/- 4 days (95% CI 34-51 days) (P = 0.002). The tumor weight in the treatment group (0.8 +/- 0.8 g) was significantly smaller than the control group (2.0 +/- 0.8 g) (P = 0.00028). No bloody ascites or diffuse peritoneal carcinomatosis were observed in the treatment group, as compared with 4 mice (26.7%) that developed bloody ascites and 6 mice (40%) which developed diffuse peritoneal carcinomatosis in the control group (P < 0.001). The treatment group had a significantly lower peripheral white blood cell count [(3.18 +/- 1.72) x 10(9) l(-1)] than the control group [(5.08 +/- 2.03) x 10(9 )l(-1)] (P < 0.05), significantly lower serum alpha fetoprotein level (101.22 +/- 20.12 microg/l) than the control group (244.87 +/- 30.24 microg/l) (P < 0.05), and significantly lower serum gamma glutamyl transpeptidase level (12.45 +/- 2.26 U/l) than the control group (20.75 +/- 3.87 U/l) (P < 0.05). No obvious treatment related toxicities were observed. CONCLUSIONS: Intraperitoneal injection of HCPT could inhibit tumor progression, reduce the extent of peritoneal carcinomatosis and improve survival of tumor bearing mice.

[In-vivo targeted imaging of hepatocellular carcinoma in nude mice using quantum dot probes].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[Quantum dots and their applications in cancer research].

Quantum dots are semiconductor nanocrystals with physical dimensions smaller than the exciton Bohr radius. As their fluorescence emissions are size-tunable, we can acquire any spectrum from ultraviolet (UV) to near-infrared by changing the particles' radiuses. The large Stokes shifts of quantum dots can be used to further improve detection sensitivity. The luminescence intensity is high and stable. Single quantum dots have longer excited state lifetimes, and they appear 10-20 times brighter than organic fluorescent dyes. And they have good biocompatibility because quantum dots with appropriate shells don't interfere with physiological processes, such as growth, development, signaling and motility. With the development of optical labeling and imaging technology, many present conventional biomedical methods have limitations in microcosmic direct real-time researches of bio-molecular interactions and early diagnosis of malignant tumors. The invention of quantum dots and their biomedical applications make them as good markers for tumor cell tracing and targeting in cancer research, such as prostate cancer, mammary cancer, cervical cancer, basal cell carcinoma, liver cancer, and melanoma. The current research is focused on tumor markers imaging and molecular interaction based on tangible carriers such as cells and tissues. The next research orientation would be to tap the potential of this highly sensitive technology to image tumor biomarkers in serum and other body fluids, so as to increase the early diagnosis rate of malignant tumors.