Early incorporated endothelial cells as origin of metastatic tumor vasculogenesis.

Vascularization of solid tumors is thought to occur by sprouting or intussusceptive angiogenesis, co-option of existing vessels, and vasculogenic mimicry after the onset of tumor hypoxia, when the tumor radius exceeds the oxygen diffusion distance. In contrast, here we show that individual endothelial cells that are incorporated into pre-hypoxic tumors give rise to tumor blood vessels via vasculogenesis. Small metastatic lung tumor sections obtained after tail-vein injection of a syngeneic breast cancer cell line in the nude mice were labeled with antibodies against endothelial cell markers.

Connexin-43 upregulation in micrometastases and tumor vasculature and its role in tumor cell attachment to pulmonary endothelium.

Background: The modulation of gap junctional communication between tumor cells and between tumor and vascular endothelial cells during tumorigenesis and metastasis is complex. The notion of a role for loss of gap junctional intercellular communication in tumorigenesis and metastasis has been controversial. While some of the stages of tumorigenesis and metastasis, such as uncontrolled cell division and cellular detachment, would necessitate the loss of intercellular junctions, other stages, such as intravasation, endothelial attachment, and vascularization, likely require increased cell-cell contact.

Lung metastatic load limitation with hyperbaric oxygen.

Despite some theoretical concern about cancer-enhancing effects ofhyperbaric oxygen (HBO2) therapy, it is frequently administered to cancer patients. We evaluated the growth of murine breast cancer cells in the lung after hyperbaric oxygen treatment in an experimental metastasis assay. Young nu/nu mice were injected intravenously with 3 x 10(3) 4T1-GFP tumor cells per g body weight followed by lung isolation, perfusion, and intact organ epifluorescence microscopy 1 to 37 days after injection.

Increased depth of cellular imaging in the intact lung using far-red and near-infrared fluorescent probes.

Scattering of shorter-wavelength visible light limits the fluorescence imaging depth of thick specimens such as whole organs. In this study, we report the use of four newly synthesized near-infrared and far-red fluorescence probes (excitation/emission, in nm: 644/670; 683/707; 786/814; 824/834) to image tumor cells in the subpleural vasculature of the intact rat lungs. Transpelural imaging of tumor cells labeled with long-wavelength probes and expressing green fluorescent protein (GFP; excitation/emission 488/507 nm) was done in the intact rat lung after perfusate administration or intravenous injection.