RESUMO
Tumor metastasis is a key factor affecting the life of patients with malignant tumors. For the past hundred years, scientists have focused on how to kill cancer cells and inhibit their metastasis in vivo, but few breakthroughs have been made. Here we hypothesized a novel mode for cancer metastasis. We show that the phagocytosis of apoptotic tumor cells by macrophages leads to their polarization into the M2 phenotype, and that the expression of stem cell related as well as drug resistance related genes was induced. Therefore, it appears that M2 macrophages have "defected" and have been transformed into the initial "metastatic cancer cells", and thus are the source, at least in part, of the distal tissue tumor metastasis. This assumption is supported by the presence of fused cells with characteristics of both macrophage and tumor cell observed in the peripheral blood and ascites of patients with ovarian cancer. By eliminating the expression of CD206 in M2 macrophages using siRNA, we show that the growth and metastasis of tumors was suppressed using both in vitro cell line and with experimental in vivo mouse models. In summary, we show that M2 macrophages in the blood circulation underwent a "change of loyalty" to become "cancer cells" that transformed into distal tissue metastasis, which could be suppressed by the knockdown of CD206 expression.
RESUMO
We studied the cobalt-doping effect on superconductivity and magnetism in a hole self-doped RbEuFe4As4 magnetic superconductor which shows superconductivity at [Formula: see text] 36.5 K and Eu2+ -spin ordering at [Formula: see text] 15 K. The Co solubility limit in RbEu(Fe1-x Co x )4As4 achieves x = 0.21 for the solid-state reaction at 880 °C. With increasing x, [Formula: see text] decreases gradually, and superconductivity eventually disappears at [Formula: see text]. A spin-density-wave transition at [Formula: see text] 35-40 K is recovered for [Formula: see text], which can be understood in terms of the hole-depletion and the disorder effects. On the other hand, [Formula: see text] remains unchanged despite the Co doping and, consequently, an intriguing superconducting ferromagnet without Meissner state is realized in the range of 0.125 [Formula: see text] 0.155. Our results indicate that the Eu2+ spins essentially decouple with superconductivity over a wide doping range, making the coexistence of superconductivity and ferromagnetism possible in the 1144-type system.
