Autotaxin inhibitor IOA-289 reduces gastrointestinal cancer progression in preclinical models.

BACKGROUND: Autotaxin (ATX) is a secreted enzyme that converts lysophosphatidylcholine to lysophosphatidic acid (LPA). LPA stimulates cell proliferation and migration and promotes wound repair following tissue damage. ATX levels are directly correlated with stage and grade in several human cancers. Several small molecule ATX inhibitors have been developed in recent years. IOA-289 is a potent ATX inhibitor, developed to treat cancers containing fibrosis. In this study, we tested IOA-289 treatment on different gastrointestinal tract tumor cell lines, in order to evaluate its effects on viability and motility. METHODS: To determine the effects on cell viability and proliferation of treatment with increasing concentrations of IOA-289, we used the crystal violet assay, a clonogenic assay in matrigel, and we evaluated the inhibitor's effect on formation of 3D spheroids in an in vitro model. The effect of IOA-289 on cell cycle phases was analysed with a redox dye reagent. Cell migration capacity was evaluated by wound healing assay and transwell migration assay. To evaluate the pro-apoptotic effect of the inhibitor, cells were stained with Annexin V and immunofluorescence and flow cytometry analysis were performed. An antibody array was also used, to discriminate, in various samples, the differential expression of 43 proteins involved in the apoptosis pathway. RESULTS: We found that IOA-289 is able to inhibit both growth and migration of gastrointestinal tract tumor cell lines, both in 2D (crystal violet assay) and 3D in vitro models (spheroid formation and clonogenic assay in matrigel). This effect is dose-dependent, and the drug is most effective when administered in FBS-free culture medium. The inhibitory effect on cell growth is due to a pro-apoptotic effect of IOA-289. Staining with FITC-conjugated Annexin V showed that IOA-289 induced a dose-dependent increase in fluorescence following incubation for 24 h, and apoptotic cells were also distinguished in flow cytometry using Annexin/PI staining. The antibody array shows that treatment with IOA-289 causes the increased expression of several pro-apoptotic proteins in all tested cell lines. CONCLUSIONS: These results indicate that IOA-289 may be an effective drug for the treatment of tumors of the gastrointestinal tract, particularly those characterized by a high degree of fibrosis.

Mitochondrial bioenergetics boost macrophage activation, promoting liver regeneration in metabolically compromised animals.

BACKGROUND AND AIMS: Hepatic ischemia-reperfusion injury (IRI) is the leading cause of early posttransplantation organ failure as mitochondrial respiration and ATP production are affected. A shortage of donors has extended liver donor criteria, including aged or steatotic livers, which are more susceptible to IRI. Given the lack of an effective treatment and the extensive transplantation waitlist, we aimed at characterizing the effects of an accelerated mitochondrial activity by silencing methylation-controlled J protein (MCJ) in three preclinical models of IRI and liver regeneration, focusing on metabolically compromised animal models. APPROACH AND RESULTS: Wild-type (WT), MCJ knockout (KO), and Mcj silenced WT mice were subjected to 70% partial hepatectomy (Phx), prolonged IRI, and 70% Phx with IRI. Old and young mice with metabolic syndrome were also subjected to these procedures. Expression of MCJ, an endogenous negative regulator of mitochondrial respiration, increases in preclinical models of Phx with or without vascular occlusion and in donor livers. Mice lacking MCJ initiate liver regeneration 12 h faster than WT and show reduced ischemic injury and increased survival. MCJ knockdown enables a mitochondrial adaptation that restores the bioenergetic supply for enhanced regeneration and prevents cell death after IRI. Mechanistically, increased ATP secretion facilitates the early activation of Kupffer cells and production of TNF, IL-6, and heparin-binding EGF, accelerating the priming phase and the progression through G1 /S transition during liver regeneration. Therapeutic silencing of MCJ in 15-month-old mice and in mice fed a high-fat/high-fructose diet for 12 weeks improves mitochondrial respiration, reduces steatosis, and overcomes regenerative limitations. CONCLUSIONS: Boosting mitochondrial activity by silencing MCJ could pave the way for a protective approach after major liver resection or IRI, especially in metabolically compromised, IRI-susceptible organs.

Snail blocks the cell cycle and confers resistance to cell death.

The Snail zinc-finger transcription factors trigger epithelial-mesenchymal transitions (EMTs), endowing epithelial cells with migratory and invasive properties during both embryonic development and tumor progression. During EMT, Snail provokes the loss of epithelial markers, as well as changes in cell shape and the expression of mesenchymal markers. Here, we show that in addition to inducing dramatic phenotypic alterations, Snail attenuates the cell cycle and confers resistance to cell death induced by the withdrawal of survival factors and by pro-apoptotic signals. Hence, Snail favors changes in cell shape versus cell division, indicating that with respect to oncogenesis, although a deregulation/increase in proliferation is crucial for tumor formation and growth, this may not be so for tumor malignization. Finally, the resistance to cell death conferred by Snail provides a selective advantage to embryonic cells to migrate and colonize distant territories, and to malignant cells to separate from the primary tumor, invade, and form metastasis.