Transforming growth factor-beta (TGF-beta) signaling exerts a wide spectrum of biological functions. To investigate TGF-beta signaling in amelogenesis, we initially assessed the expression of TGF-beta1 and TGF-beta receptor 1 (TGFBR1) in developing teeth by immunohistochemistry. Both TGF-beta1 and TGFBR1 were strongly expressed in secreting ameloblasts. Next, we studied the effects of TGF-beta signaling on the expression of MMP20 and KLK4 mRNA using ameloblast-lineage cells (ALC) in vitro. Our RT-PCR study showed that TGF-beta1, TGFBR1, and enamel matrix proteases (MMP20 and KLK4) were expressed in ALC. Following TGF-beta1 treatment, the expression of MMP20 mRNA, but not KLK4 mRNA, was significantly upregulated. To further confirm the TGF-beta signaling involvement in the MMP20 expression, we constructed the activated TGFBR1 vector and transfected the construct into ALC. The activated TGFBR1 notably promoted MMP20 expression, but had no obvious effects on the KLK4 mRNA expression. Our studies strongly suggest that TGF-beta signaling involved in amelogenesis is partially mediated by regulating the expression of MMP20 mRNA. Anat Rec, 292:885-890, 2009. V V C 2009 Wiley-Liss, Inc.

The treatment of lymphatic malformations (LMs) represents a great clinical challenge. The present study reported on the treatment of 68 infants with cervical macrocystic LMs using surgical resection. The cases were retrospectively analyzed. All patients underwent pre-operative ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) examinations. The surgery was performed under general anesthesia with endotracheal intubation. Ultrasonograms showed that 24 cases were monolocular, 44 were multilocular, 16 had no echo, 20 had a uniform low-level echo and 32 had a non-uniform low-level echo. CT showed non-enhancing low-attenuating cystic lesions and attenuation values of 10–45 HU. The magnetic resonance images of the LMs showed a low signal intensity on T1-weighted imaging (WI) and a high signal intensity on T2-WI. Complete resection was achieved in 56 patients, subtotal resection in eight and partial resection in four. Two complications were noted, including reversible paresis of the marginal mandibular branch of the facial nerve and a surgical-site infection. One patient in whom partial resection was achieved had recurrence at ~2 months after the surgery. Ultrasonography, CT and MRI clearly demonstrated the size, shape, extent and adjacent structures of LMs, which aided in surgical planning and assessment of potential risks. Surgical excision increased the chances of cure and was relatively safe for infants aged <1 year. Location and extent, rather than age, were determined to be the most important factors for successful surgical treatment.

The cancer stem cell (CSC) model suggests that a small subset of cancer cells possess stem cell properties and plays a crucial role in tumor initiation, metastasis and resistance to anticancer therapy. Exploration of the specific therapies targeting at CSCs has been a crucial issue in antitumor research. Gastric cancer (GC) cells often exist in an ischemic microenvironment with acidic conditions in vivo, thus maintenance of cellular pH homeostasis is important for the survival and function of GC cells. Proton pump inhibitors (PPIs) may prevent intracellular proton extrusions which consequently reduce cancer cell survival under acidic conditions. The effects of PPIs on the suppression of the viability and invasiveness of GC cells have been reported, but the functional role of pantoprazole (PPZ) in GC cells remains unknown. In this study, we found that when cells were treated with PPZ, the 5‑fluorouracil (5‑FU) chemosensitivity was upregulated, meanwhile the sphere formation ability and the relative expression levels of stem cell markers CD44, CD24, ABCG2, EpCAM and Lgr5 were significantly decreased. It was hypothesized that PPZ inhibits the GC CSCs. Successively a sphere formation culture was performed to establish CSC models and the effect of PPZ on GC CSCs from SGC-7901 and HGC‑27 cells was explored. The addition of PPZ reduced the relative expression of CSC markers and anti‑drug markers accompanied by a decrease in proliferation, 5‑FU chemoresistance and self‑renewal capacity via epithelial‑mesenchymal transition (EMT)/β‑catenin pathways. The study suggests that PPZ could be a promising novel specific therapeutic strategy for targeting GC CSCs.

Runt-related transcription factor 2 (Runx2) is involved in the early stage of tooth development. However, only few studies have reported the role of Runx2 in enamel development, which may be attributed to that Runx2 full knockout mice cannot survive after birth. In the present study, we successfully established a Runx2-deficient mouse model using a conditional knockout (cKO) method. We observed a significant reduction in the degree of mineralization and the decreased size of enamel rods in cKO mice. Histological analysis showed the retained enamel proteins in enamel layer at maturation stage in cKO molars. Further analysis by qRT-PCR revealed that the expressions of genes encoding enamel structure proteins, such as amelogenin (AMELX), ameloblastin (AMBN) and enamelin (ENAM), were increased in cKO enamel organs. On the other hand, the expression of kallikrein-related peptidase-4 (KLK4) at the mRNA and protein levels was dramatically decreased from late secretory stage to maturation stage in cKO enamel organs, while the expression of matrix metalloproteinase-20 (MMP-20) was not significantly altered. Finally, immunohistochemistry indicated that the uptake of amelogenins by ameloblasts was significantly decreased in cKO mice. Taken together, Runx2 played critical roles in controlling enamel maturation by increasing synthesis of KLK4 and decreasing synthesis of AMELX, AMBN and ENAM.