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Essentials Factor Xa (FXa)-targeting direct oral anticoagulants (DOACs) reduce venous thromboembolism (VTE) The effects of FXa-targeting DOACs on cancer progression remain to be studied In xenograft models, a FXa-targeting DOAC did not inhibit breast cancer growth and metastasis A thrombin-targeting DOAC, dabigatran, also did not inhibit breast cancer growth and metastasis ABSTRACT: Background Factor Xa-targeting DOACs were recently found to reduce recurrent VTE efficiently in cancer patients when compared to the standard treatment with low-molecular-weight heparins (LMWHs). While the anticancer effects of LMWHs have been extensively studied in preclinical cancer models, the effects of FXa-targeting DOACs on cancer progression remain to be studied. Objective We investigated whether the FXa-targeting DOAC rivaroxaban and the thrombin-targeting DOAC dabigatran etexilate (DE) affected human breast cancer growth and metastasis in orthotopic xenograft models. Methods/results Mice that were put on a custom-made chow diet supplemented with rivaroxaban (0.4 or 1.0 mg/g diet) or dabigatran etexilate (DE) (10 mg/g diet) showed prolonged ex vivo coagulation times (prothrombin time [PT] and activated partial thromboplastin time [aPTT] assay, respectively). However, rivaroxaban and DE did not inhibit MDA-MB-231 tumor growth and metastasis formation in lungs or livers of 7-week-old fully immunodeficient NOD/SCID/ƴC -/- (NSG) mice. Comparable data were obtained for rivaroxaban-treated mice when using NOD-SCID mice. Rivaroxaban and DE treatment also did not significantly inhibit tumor growth and metastasis formation when using another human triple negative breast cancer (TNBC) cell line (HCC1806) in NOD-SCID mice. The FXa and thrombin-induced gene expression of the downstream target CXCL8 in both cell lines, but FXa and thrombin, did not significantly stimulate migration, proliferation, or stemness in vitro. Conclusion Although effectively inhibiting coagulation, the DOACs rivaroxaban and DE did not inhibit orthotopic growth and metastasis of human TNBC. It remains to be investigated whether DOACs exert antitumorigenic effects in other types of cancer.

It has been long-established that cancer and thrombosis are linked, but the exact underlying pathological mechanism remains to be unraveled. As the initiator of the coagulation cascade, the transmembrane glycoprotein tissue factor (TF) has been intensely investigated for its role in cancer-associated thrombosis and cancer progression. TF expression is regulated by both specific oncogenes and environmental factors, and it is shown to regulate primary growth and metastasis formation in a variety of cancer models. In clinical studies, TF has been shown to be overexpressed in most cancer types and is strongly associated with disease progression. While TF clearly associates with cancer progression, a prominent role for TF in the development of cancer-associated thrombosis is less clear. The current concept is that cancer-associated thrombosis is associated with the secretion of tumor-derived TF-positive extracellular vesicles in certain tumor types. To date, many therapeutic strategies to target TF—both in preclinical and clinical phase—are being pursued, including targeting TF or the TF:FVIIa complex by itself or by exploiting TF as a docking molecule to deliver cytotoxic compounds to the tumor. In this review, the authors summarize the current understanding of the role of TF in both cancer progression and cancer-associated thrombosis, and discuss novel insights on TF as a therapeutic target as well as a biomarker for cancer progression and VTE.

It has been well-established that cancer results in a hypercoagulable state and an increased risk for venous thromboembolism (VTE). More recently, it has been suggested that coagulation may also affect cancer progression and metastasis. Cancer patients with VTE are currently treated with the anticoagulant low molecular weight heparins (LMWHs). Preclinical studies have shown that LMWHs can inhibit metastasis formation in several types of cancer, but beneficial effects of LMWHs on survival have not been consistently found in clinical trials. Recently, a new class of anticoagulants are available for treatment of VTE, the so-called direct oral anticoagulant (DOACs), which include dabigatran and rivaroxaban, a direct thrombin and FXa inhibitor, respectively. However, the effects of DOACs on cancer are currently under studied.

Glucagon-like peptide-1-based (GLP-1-based) therapies improve glycemic control in patients with type 2 diabetes. While these agents augment insulin secretion, they do not mimic the physiological meal-related rise and fall of GLP-1 concentrations. Here, we tested the hypothesis that increasing the number of intestinal L cells, which produce GLP-1, is an alternative strategy to augment insulin responses and improve glucose tolerance. Blocking the NOTCH signaling pathway with the γ-secretase inhibitor dibenzazepine increased the number of L cells in intestinal organoid-based mouse and human culture systems and augmented glucose-stimulated GLP-1 secretion. In a high-fat diet-fed mouse model of impaired glucose tolerance and type 2 diabetes, dibenzazepine administration increased L cell numbers in the intestine, improved the early insulin response to glucose, and restored glucose tolerance. Dibenzazepine also increased K cell numbers, resulting in increased gastric inhibitory polypeptide (GIP) secretion. Using a GLP-1 receptor antagonist, we determined that the insulinotropic effect of dibenzazepine was mediated through an increase in GLP-1 signaling. Together, our data indicate that modulation of the development of incretin-producing cells in the intestine has potential as a therapeutic strategy to improve glycemic control.

The interest in the use of humanized mouse models for research topics like Graft versus Host Disease (GvHD), allograft studies and other studies to the human immune system is growing. The design of these models is still improving and enables even more complicated studies to these topics. For researchers it can be difficult to choose the best option from the current pool of available models. The decision will depend on which hypothesis needs to be tested, in which field of interest, and therefore ‘the best model’ will differ from one to another. In this review, we provide a guide to the most common available humanized mouse models, with regards to different mouse strains, transplantation material, transplantation techniques, pre- and post-conditioning and references to advantages and disadvantages. Also, an evaluation of experiences with humanized mouse models in studies on GvHD and allograft rejection is provided.