Tube formation is one of the fundamental events required by angiogenesis and lymphangiogenesis. To date, there is little knowledge on the effects of hypoxia on tube formation of human dermal lymphatic endothelial cells (HDLECs). In this study, we found that tube formation of HDLECs was inhibited under hypoxic condition with decreased expressions of VEGF-D, CEACAM1 and Prox1 genes. However, hypoxia-induced inhibition of tube formation of HDLECs was reversed by conditional media from hypoxic tumor cells. After knockdown of CEACAM1 by siRNA transfection, tube formation of HDLECs was increased with elevated Prox1 expression, suggesting that CEACAM1 downregulates Prox1 and plays an inhibitory role in tube formation of HDLECs. Since the expressions of CEACAM1 and Prox1 were both decreased by hypoxia, there are additional mechanisms downregulating Prox1 expressions during hypoxia-inhibited tube formation of HDLECs.

管形成是血管生成和淋巴管生成所需的基本事件之一。迄今为止，关于缺氧对人真皮淋巴内皮细胞（HDLEC）的管形成的影响的了解还很少。在这项研究中，我们发现低氧条件下可抑制HDLECs的管形成，并降低VEGF-D，CEACAM1和Prox1的表达。基因。然而，低氧肿瘤细胞的条件培养基逆转了低氧诱导的对HDLECs管形成的抑制作用。通过siRNA转染敲低CEACAM1后，HDLECs的管形成随Prox1表达的升高而增加，这表明CEACAM1下调Prox1并在HDLECs的管形成中起抑制作用。由于缺氧会降低CEACAM1和Prox1的表达，因此在缺氧抑制HDLECs管形成过程中还有其他下调Prox1表达的机制。