The Spalt-like 4 (Sall4) zinc finger protein is a critical transcription factor for pluripotency in embryonic stem cells (ESCs). It is also involved in the formation of a variety of organs, in mice, and humans. We report the essential roles of Sall4 in mouse primordial germ cell (PGC) specification. PGC specification is accompanied by the activation of the stem cell program and repression of the somatic cell program in progenitor cells. Conditional inactivation of Sall4 during PGC specification led to a reduction in the number of PGCs in embryonic gonads. Sall4 del/del PGCs failed to translocate from the mesoderm to the endoderm and underwent apoptosis. In Sall4 del/del PGC progenitors, somatic cell program genes (Hoxa1 and Hoxb1) were derepressed, while activation of the stem cell program was not impaired. We demonstrated that in differentiated ESCs, Sall4 bound to these somatic cell program gene loci, which are reportedly occupied by Prdm1 in embryonic carcinoma cells. Given that Sall4 and Prdm1 are known to associate with the histone deacetylase repressor complex, our findings suggest that Sall4 suppresses the somatic cell program possibly by recruiting the repressor complex in conjunction with Prdm1; therefore, it is essential for PGC specification. STEM CELLS 2015;33:289-300

In the colon of patients with ulcerative colitis (UC), decreased function of the paracellular barrier, especially hypofunction of the tight junction, is associated with pathological conditions. However, there has been no report to date on the function of tight junctions in the small intestine. Here, we focused on the barrier function of the small intestine, especially in tight junctions, and compared it with that of the colon. Dextran sulfate sodium (DSS) was used to induce ulcerative colitis in rats in order to evaluate the function of the paracellular barrier in the jejunum, ileum, and colon. An in vitro diffusion chamber method was used to evaluate membrane resistance, which is an index of tight junction function and mucosal permeability, using 6-carboxyfluorescein (6-CF), a paracellular marker. In the jejunum and colon, with decrease of membrane resistance in the DSS group, mucosal permeability increased, whereas no marked difference was observed in the ileum. In the in situ closed-loop method, absorption of 6-CF from the jejunum was higher than that from the ileum.Immunohistochemical staining of claudin-4 showed heterogeneous attenuation of claudin-4 in the jejunum. Pharmacokinetic parameters were calculated from the blood concentration after intravenous injection and oral administration of 6-CF. In the DSS group, there was a delay in the elimination phase, suggesting a decrease in renal function, and an increase in maximum blood concentration, associated with an increased absorption rate constant. The increased absorption and decreased renal function due to decreased paracellular barrier function in the small intestine and colon may cause fluctuations in drug efficacy and side effects. K E Y W O R D S membrane resistance, paracellular route, small intestine, tight junction, ulcerative colitis

Purpose: The purpose of this study was to investigate the relationships among plasma concentrations of lenvatinib, angiopoietin (Ang)-1 and Ang-2, and clinical responses to lenvatinib therapy in Japanese patients with thyroid cancer. Methods: Plasma concentrations of lenvatinib (C0) and Ang-1 and -2 were measured by HPLC and ELISA, respectively.Results: The median change rates of Ang-1 and Ang-2 at 1 month after treatment from baseline in 36 patients were -15.3% and -48.4%, respectively. However, the change of Ang-1 and Ang-2 at 1 month from baseline did not correlate with lenvatinib C0. In patients with partial response (PR) and stable disease to lenvatinib, Ang-2 at 1 month were significantly lower than Ang-2 at baseline (P < 0.001 and P < 0.05, respectively), but were not significantly lower in patients with progressive disease. The area under the ROC for PR prediction was 0.667, giving the best sensitivity (69.2%) and specificity (73.9%) at a threshold of the change rate of Ang-2 of -49.83%. A one year overall survival for patients having the change rate of Ang-2 of at least -49.83% and less than -49.83% were 62.5% and 40%, respectively. In patients who continued treatment with lenvatinib for 1 year, Ang-2 at 1 month and 1 year after treatment were significantly lower than those at baseline (each P < 0.001).Conclusion: The change of Ang-2 at 1 month after treatment from baseline rather than simply the Ang-2 level at baseline may be important as a biomarker of the inhibitory effect of angiogenesis by lenvatinib.

The purpose of this study was to investigate the relationships among plasma concentrations (C0) of lenvatinib, angiopoietin (Ang)-1 and Ang-2, and clinical responses to lenvatinib therapy in thyroid cancer patients. The median change rates of Ang-1 and Ang-2 at 1 month after treatment from baseline in all patients were − 15.3% and − 48.4%, respectively. However, the change of Ang-1 and Ang-2 at 1 month from baseline did not correlate with lenvatinib C0. In patients with partial response (PR) and stable disease to lenvatinib, Ang-2 at 1 month were significantly lower than Ang-2 at baseline (P < 0.001 and P < 0.05, respectively), but were not significantly lower in patients with progressive disease. The area under the ROC for PR prediction was 0.667, giving the best sensitivity (69.2%) and specificity (73.9%) at a threshold of the change rate of Ang-2 of -49.83%. In patients who continued treatment with lenvatinib for 1 year, Ang-2 at 1 month and 1 year were significantly lower than those at baseline (each P < 0.001). The change of Ang-2 at 1 month after treatment from baseline rather than simply the Ang-2 level at baseline may be important as a biomarker of the inhibitory effect of angiogenesis by lenvatinib.