Endotoxin/lipopolysaccharide (LPS), a cell wall component of Gram-negative bacteria, is a potent inflammatory stimulus. We previously reported that LPS increased the growth of experimental metastases in a murine tumor model. Here, we examined the effect of LPS exposure on key determinants of metastasis-angiogenesis, tumor cell invasion, vascular permeability, nitric oxide synthase (NOS) and matrix metalloproteinase 2 (MMP2) expression. BALB/c mice bearing 4T1 lung metastases were given an intraperitoneal (i.p.) injection of 10 g LPS or saline. LPS exposure resulted in increased lung weight and incidence of pleural lesions. LPS increased angiogenesis both in vivo and in vitro. Most cancer patients ultimately succumb to metastatic disease, and up to 50% of cancer patients already have metastatic deposits at the time of diagnosis. 1 In many cases, the primary tumor can be successfully treated by surgery, radiotherapy, chemotherapy or a combination but the subsequent growth of previously dormant or clinically undetectable metastatic deposits presents a serious obstacle to the complete eradication of the disease. Elucidating factors that influence the development and progression of metastatic disease is critical to the development of effective therapies for patients with metastatic deposits.Metastatic tumor growth involves a complex series of sequential events involving a number of cell types, cytokines and pathways. After the initial transformation event, growth of a primary tumor is accompanied by extensive angiogenesis. Cells with a metastatic phenotype invade the tissue stroma and penetrate the blood vessels to enter the circulation. The majority of tumor cells entering the circulation are rapidly destroyed but those that do survive can then become trapped in organ capillary beds and extravasate into the organ parenchyma. Cell proliferation and vascularization of the secondary deposit completes the metastatic process. 2 Endotoxin/lipopolysccharide (LPS), a cell wall constituent of Gram-negative bacteria, is released during growth or lysis of bacteria and acts as a potent inflammatory stimulus, eliciting a range of cytokines, growth factors and inflammatory mediators. LPS and some bacteria have been shown to have angiogenic activity. [3][4][5] Inflammation has been linked with angiogenesis, resulting in changes in permeability, activation of endothelium and vessel remodeling. 6 In support of a link between inflammation and tumor progression, there is a growing body of evidence that anti-inflammatory agents such as the nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit cyclo-oxygenase activity, inhibit both tumorigenesis and growth of colon and mammary tumors. 7 Endotoxin is ubiquitously present in air, and we previously implicated endotoxin in surgically induced tumor growth. 8,9 Endogenous gut bacteria are a major source of endotoxin, which can translocate across the gut into the circulation following surgical trauma or thermal injury. 10 -12 Vascular endothelial growth factor (VEGF), also known as va...

Patients with breast cancer brain metastases cannot be cured and have a poor prognosis, with a median survival time of six months after diagnosis, despite developments in diagnostic and therapeutic modalities. In large part the progress in understanding the biology of breast cancer brain metastasis has been limited by the lack of suitable cell lines and experimental models. The objective of this study was to develop a reliable experimental model to study the pathogenesis of breast cancer brain metastases, using intra-internal carotid artery injection of breast cancer cells into nude mice. Brain metastasis-selected variant cells were recovered after three cycles of injection into the internal carotid artery of nude mice and harvest of brain metastases, resulting in variants termed MDA-231 BR1, -BR2 and -BR3. The metastasis-selected cells had increased potential for experimental brain metastasis and mice injected with these cells had significantly shorter mean survival than mice injected with the original cell line. Brain metastatic lesions of the selected variants contained significantly more CD31-positive blood vessels than metastases of the non-selected cell line. The variants selected from brain metastases released significantly more VEGF-A and IL-8 into culture supernatants than the original cell line, and more VEGF-A RNA when cultured in normoxic conditions. Mice injected with MDA-231 BR3 into the carotid artery were treated with the VEGF-receptor tyrosine kinase inhibitor PTK787/Z 222584. Oral administration of the inhibitor resulted in a significant decrease in brain tumor burden, reduced CD31-positive vessels in the brain lesions and incidence of PCNA positive tumor cells, and increased apoptosis in the tumor, as measured by TUNEL labeling. We conclude that elevated VEGF expression contributes to the ability of breast cancer cells to form brain metastases. Targeting endothelial cells with a VEGF-receptor specific tyrosine kinase inhibitor reduced angiogenesis and restricted the growth of the brain metastases.

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The purpose of this study was to determine the effects of interferon -(IFN -) gene transfer on the growth of PC3MM2 human prostate cancer cells in nude mice. Intralesional delivery of an adenoviral vector encoding murine IFN -( AdIFN -) , but not a vector encoding bacterial -galactosidase ( AdLacZ ) , suppressed PC3MM2 tumors in a dose -dependent manner. At the highest dose ( 2Â10 9 plaque -forming units, PFU ) , a single injection of AdIFN -( but not AdLacZ ) suppressed orthotopic PC3MM2 tumors and development of metastasis by 80%, and eradicated the tumors in 20% of mice. Immunohistochemical staining showed that AdIFN -± treated tumors contained fewer microvessels, fewer proliferating cells, and more apoptotic cells than did the control tumors. Compared with controls, tumors injected with AdIFN -expressed higher levels of IFN -and inducible nitric oxide synthase ( iNOS ) and lower levels of basic fibroblast growth factor ( bFGF ) and transforming growth factor 1 ( TGF -1). In vitro analysis indicated that expression of bFGF and TGF -1 in PC3MM2 cells could be suppressed by the nitric oxide donor sodium nitroprusside. These data suggest that intratumoral delivery of the IFN -gene with adenoviral vectors could be an effective therapy for prostate cancer and that tumor suppression by AdIFN -correlated with up -regulation of iNOS and down -regulation of angiogenesis.

Toll-like receptors (TLRs) are pivotal components of the innate immune response. Activation of the innate immune system and subsequent chronic low-grade inflammation are thought to be involved in the pathogenesis of atherosclerosis and type 2 diabetes. In the study, we genotyped TLRs gene polymorphisms, including TLR2 Arg677Trp and Arg753Gln, TLR4 Asp299Gly and Thr399Ile, TLR9-1486T/C and -1237T/C. The frequencies of TT, TC and CC genotype of TLR9-1486T/C mutation were 39.6%, 45.8% and 14.6%, respectively; the frequencies of T allele and C allele were 62.5% and 37.5%. However, neither of these parameters was statistically significant among study groups. In addition, we were surprised to find that the commonly reported TLR SNPs in the Western countries, like TLR2 Arg677Trp or Arg753Gln, TLR4 Asp299Gly or Thr399Ile and TLR9-1237T/C, were not polymorphic at all in all study subjects. In conclusion, our data suggests that TLR2 Arg677Trp or Arg753Gln, TLR4 Asp299Gly or Thr399Ile and TLR9-1237T/C polymorphisms have low frequency and TLR9-1486T/C polymorphism may not be a suitable marker in predicting the susceptibility to type 2 diabetes or coronary artery disease in the Chinese Han population.