Differential effects of anticoagulants on tumor development of mouse cancer cell lines B16, K1735 and CT26 in lung

Abstract

Cancer progression is facilitated by blood coagulation. Anticoagulants, such as Hirudin and low molecular weight heparins (LMWHs), reduce metastasis mainly by inhibition of thrombin formation and L-and Pselectin-mediated cell-cell adhesion. It is unknown whether the effects are dependent on cancer cell type. The effects of anticoagulants on tumor development of K1735 and B16 melanoma cells and CT26 colon cancer cells were investigated in mouse lung. Tumor load was determined noninvasively each week up to day 21 in all experiments using bioluminescence imaging. Effects of anticoagulants on tumor development of the three cell lines were correlated with the fibrin/fibrinogen content in the tumors, expression of tissue factor (TF), protease activated receptor (PAR)-1 and -4 and CD24, a ligand of L-and P-selectins. Hirudin inhibited tumor development of B16 cells in lungs completely but did not affect tumor growth of K1735 and CT26 cells. Low molecular weight heparin did not have an effect on K1735 melanoma tumor growth either. TF and PAR-4 expression was similar in the three cell lines. PAR-1 and CD24 were hardly expressed by K1735, whereas CT26 cells expressed low levels and B16 high levels of PAR-1 and CD24. Fibrin content of the tumors was not affected by LMWH. It is concluded that effects of anticoagulants are dependent on cancer cell type and are correlated with their CD24 and PAR-1 expression.Keywords B16 melanoma Á CT26 colon carcinoma Á K1735 melanoma Á Hirudin Á Low molecular weight heparin Á Selectin Á PAR

Long‐term thrombin inhibition promotes cancer cell extravasation in a mouse model of experimental metastasis

“…We propose here the novel hypothesis that this churning effect causes erythrocyte destruction, leading to hemolysis, reflected as a decrease in plasma haptoglobin. A similar mechanism has been proposed in patients with sickle cell disease, [3] and the severity of PH from sickle cell disease is closely linked to the frequency and intensity of hemolytic episodes [4]. However, in the rat model of PE, we observed the confounding effect of induction of haptoglobin, apparently secondary to the stresses of anesthesia and surgery.…”

“…low molecular weight heparin (LMWH)] of cancer patients significantly improves survival in clinical trials [2]. However, the mechanisms by which anticoagulants may interfere with tumor growth and metastasis are diverse, remain poorly defined, and are dependent on the type of cancer [3], the individual anticoagulant [4], and treatment regimen [5]. The direct thrombin inhibitor hirudin, for instance, dramatically reduced the number of lung metastases when administered just before cancer cell inoculation [6].…”

Lysophosphatidylcholine Pretreatment Reduces VLA-4 and P-Selectin–Mediated B16.F10 Melanoma Cell Adhesion In vitro and Inhibits Metastasis-Like Lung Invasion In vivo

“…Antimetastatic effects of heparin due to different molecular targets (e.g., P-or L-selectin and VLA-4), also affected by LysoPC in our study, are well documented (32)(33)(34)(35). To compare the effects of LysoPC pretreatment of B16.F10 cells and intravenous heparin, we analyzed metastatic spread of control and 450 mmol/L pretreated B16.F10 cells in mice heparinized with 50 IU, which comes close to the dose known to have the maximum inhibitory effect on metastatic spread in the B16.F10 model (32).…”

“…Using the highly metastatic murine melanoma cell line B16.F10 (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), incubated with LysoPC containing saturated FA residues (8), a striking uptake and membrane integration of the FAs of LysoPC into the melanoma cells was observed in vitro. This treatment also reduced the in vitro interaction of B16.F10 cells with platelets via P-selectin as well as the binding of tumor cell integrin VLA-4 to VCAM-1 (34).…”

The Role of Adhesion Receptors in Melanoma Metastasis and Therapeutic Intervention Thereof

“…This is the rate-limiting step of the metastatic cascade before they can extravasate and form metastases (Figure 1). An insight into the hematogenous phase of tumor cell distribution is given by numerous animal models of experimental metastasis, which dominantly used melanoma cell lines due to their rapid metastatic colonization tendency (Ludwig et al, 2004;Bereczky et al, 2005;Ludwig et al, 2006;Mousa et al, 2006;Niers et al 2009). Although these models do not completely recapitulate the natural processes of metastatic spread, the timely defined presence of tumor cells in the blood systems allows for characterization and evaluation of cellular contacts within the phase of hematogenous distribution.…”