Purpose: The anaphylatoxin C5a is a chemoattractant that induces leukocyte migration via C5a receptor (C5aR). There is emerging evidence that C5a is generated in the cancer microenvironment. We therefore sought C5aR expression and a direct influence of the C5a-C5aR axis on cancer cells.Experimental Design: C5aR expression was investigated in human cancer tissues and cell lines. Effects of C5a stimulation on cancer cells were studied by cytoskeletal rearrangement, time-lapse analysis, Matrigel chamber assay, and invasion in nude mouse in a comparison of C5aR-expressing cancer cells with control cells.Results: C5aR was aberrantly expressed in various human cancers. Several cancer cell lines also expressed C5aR. C5a triggered cytoskeletal rearrangement and enhanced cell motility three-fold and invasiveness 13-fold of C5aR-expressing cancer cells. Such enhancement by C5a was not observed in control cells. Cancer cell invasion was still enhanced in the absence of C5a concentration gradient and even after the removal of C5a stimulation, suggesting that random cell locomotion plays an important role in C5a-triggered cancer cell invasion. C5a increased the release of matrix metalloproteinases (MMP) from cancer cells by two-to 11-fold, and inhibition of MMP activity abolished the C5a-enhancing effect on cancer cell invasion. Compared with control cells, C5aR-expressing cells spread 1.8-fold more broadly at implanted nude mouse skin sites only when stimulated with C5a.Conclusions: These results illustrate a novel activity of the C5a-C5aR axis that promotes cancer cell invasion through motility activation and MMP release. Targeting this signaling pathway may provide a useful therapeutic option for cancer treatment.
Our results show that transapical aortic cannulation is safe and useful for repair of type A aortic dissection. There are advantages to transapical aortic cannulation, such as simple and quick cannulation technique, sufficient antegrade aortic flow, and the reliability of true lumen perfusion with decreased risk of stroke and malperfusion.
What do we know about the output effects of fiscal policy in low income countries (LICs)? There are very few empirical studies on the subject. This paper fills this gap by estimating the output effects of government spending shocks in LICs. Our analysis—based on the local projection method—finds that the output effects in LICs are markedly lower than those in AEs and marginally smaller than those in EMs. We also find that in LICs, the output effects are larger (i) during recessions; (ii) under a fixed exchange rate regime; and/or (iii) with higher quality of institutions. Our analysis could not confirm any statistically significant output effect under floating exchange rate regimes. For the estimation of the output effects of fiscal spending shocks, it is thus important to consider the state of the economy and the country’s structural characteristics. Our results imply that the output costs of fiscal adjustment in LICs may not be as large as previously thought, especially if adopted outside of a recession, based on cutting public consumption, and accompanied by reform to enhance institutions.
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