High Mycoplasma infection in gastric cancer tissues suggests a possible association between Mycoplasma infection and tumorigenesis. By using human gastric cancer cells AGS and mouse melanoma cells B16F10 stably expressing p37, the major immunogen of Mycoplasma hyorhinis, we found that p37 enhanced cell motility, migration, and invasion in vitro. With experimental metastasis model in C57BL/6 mice, p37 adenovirus-infected B16F10 cells formed more metastasis lesions in the lung. Furthermore, p37 promoted the phosphorylation of epidermal growth factor receptor (EGFR) and extracellular signal-regulated kinase and the activity of matrix metalloproteinase-2 (MMP-2). Inhibitor of MMPs significantly blocked p37-induced EGFR but has little effect on extracellular signal-regulated kinase phosphorylation, whereas the p37-induced MMP-2 activation was only partially suppressed by inhibitor of MEK1/2 or by inhibitor of EGFR. However, all these inhibitors significantly reduced the p37-induced invasiveness of AGS cells. These results suggest that p37 may stimulate invasion by increasing the activity of MMP-2, thereby inducing EGFR phosphorylation and contributing to tumor metastasis on M. hyorhinis infection. p37 and its regulated molecules could be the potential targets for cancer therapy. [Mol Cancer Ther 2008;7(3):530 -7]
Summaryp37 protein is a membrane lipoprotein of Mycoplasma hyorhinis, and our previous work showed that there was high ratio of M. hyorhinis infection in human gastric carcinoma. To investigate the possible functions of p37 in cancer development, the nucleotide sequence of p37 gene was modified and expressed well in transfected cells. We found that p37 localized at the Golgi apparatus and could be secreted out of the cell. Human gastric cancer cells AGS, after being transfected with the p37 gene, were smaller, more spherical and easy to detach from each other. Their adhesion to matrix was also diminished and cytoskeleton in these stable p37 AGS cell was rearranged and transcription co-factor b-actin was transferred to nucleolus with down-regulation of ICAM-1 and integrin b1. These findings will be helpful for us to elucidate the effects of p37 on eukaryotic cells as well as to better understand the potential relationship between cancer and mycoplasma infection.
Evidence of Mycoplasma hyorhinis infection in human gastric cancer tissues has been found in previous work. In this study, we demonstrate that the expression of p37, a membrane lipoprotein of M. hyorhinis, in mammalian cells induces antisenescence, enhances clonogenicity in soft agar, and co-operates with human epidermal growth factor receptor-related 2 to inhibit cell adhesion. Conversely, truncated p37 protein, with the first 28 amino acids deleted from its N terminal, promotes cell senescence. Taken together, our findings suggest that p37 promotes malignant changes in mammalian cells. With the identification of this molecular component, which is responsible for mycoplasma malignancy-promoting activity, it is possible that a better understanding of the relationship between M. hyorhinis infection and human gastric cancers will lead to novel diagnostics and therapeutics.
Solution-processed PbS quantum dot light-emitting diodes (QLEDs) with emission in the second near-infrared window (NIR-II, 1100–1700 nm) are excellent candidates as light sources for optical communication, night vision, and biomedical monitoring. However, it is still a tremendous challenge to achieve high-radiance PbS QLEDs due to serious QD surface traps and unbalanced charge injection. Herein, highly monodisperse PbS QDs with tailored facet growth were successfully synthesized by the continuous precursor injection method. The synthesized PbS QDs revealed a tunable absorption peak from 1200 to 1700 nm with a supernarrow full width at half-maximum (fwhm; <105 nm). The tailored surface facet growth effectively decreased the nonpolar (100) facet and surface defects. Furthermore, with a multilayered organic–inorganic hybrid architecture of indium tin oxide (ITO)/poly(ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS)/poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl))-diphenylamine) (TFB)/PbS QDs/ZnO/Al, the novel infrared PbS QLED exhibited an excellent maximum radiance of 16.14 W sr–1 m–2 at 6.15 V with a shortwave-infrared electroluminescence at ∼1530 nm. Importantly, the NIR-II QLEDs using facet-tailored PbS QDs with the EL peak between 1100 and 1700 nm represented extremely high radiances. The excellent performances are ascribed to the passivated PbS QDs with a tailored surface facet and the hybrid device structure for charge injection balance. This work provides an effective approach for the preparation of high-quality PbS QDs and is expected to significantly boost the potential commercial applications of PbS NIR-II QLEDs.
PbS/CdS quantum dots (QDs) have attracted much attention in the applications of photonic devices owing to their excellent saturable absorption properties. Here, highly monodisperse and perfect crystalline PbS/CdS QDs with...
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