Yoshiaki Kamei

Serum autoantibody to sideroflexin 3 as a novel tumor marker for oral squamous cell carcinoma

The purpose of this study is to establish a tumor marker that can be applied for the early detection and follow‐up of oral cancer patients. Employing the proteomic approach using MALDI TOF‐MS, 2‐DE, patients sera and culturing cell lines, the serum autoantibodies (autoAbs) were screened and the serum levels were estimated by ELISA. Targeting the tumor cell invasion into the surrounding stromal tissues, MRC‐5 human fibroblasts were employed as the target cells and a mitochondrial membrane protein, sideroflexin 3 (SFXN3), was identified. The serum anti‐SFXN3‐autoAb levels elevated in patients with the oral squamous cell carcinoma significantly: with 77% sensitivity and 89% specificity against control samples. The serum anti‐SFXN3‐autoAb levels were mildly correlated with the primary tumor sizes, however, the levels were slightly highly elevated in T1 early cancer. An immunohistochemical analysis revealed that the SFXN3 protein is expressed in the stromal fibroblasts between the caner nests and also in the basal layer of the squamous epithelium. Changes in the serum anti‐SFXN3‐autoAb levels after therapy correlated with the clinical tumor burden. These findings demonstrated that the serum anti‐SFXN3‐autoAb is worthy of clinical evaluation as a potentially of the novel tumor maker for the early detection of oral squamous cell carcinoma.

A Truncated form of CD200 (CD200S) Expressed on Glioma Cells Prolonged Survival in a Rat Glioma Model by Induction of a Dendritic Cell-Like Phenotype in Tumor-Associated Macrophages.

CD200 induces immunosuppression in myeloid cells expressing its receptor CD200R, which may have consequences for tumor immunity. We found that human carcinoma tissues express not only full-length CD200 (CD200L) but also its truncated form, CD200S. Although CD200S is reported to antagonize the immunosuppressive actions of CD200L, the role of CD200S in tumor immunity has never been investigated. We established rat C6 glioma cell lines that expressed either CD200L or CD200S; the original C6 cell line did not express CD200 molecules. The cell lines showed no significant differences in growth. Upon transplantation into the neonatal Wistar rat forebrain parenchyma, rats transplanted with C6-CD200S cells survived for a significantly longer period than those transplanted with the original C6 and C6-CD200L cells. The C6-CD200S tumors were smaller than the C6-CD200L or C6-original tumors, and many apoptotic cells were found in the tumor cell aggregates. Tumor-associated macrophages (TAMs) in C6-CD200S tumors displayed dendritic cell (DC)-like morphology with multiple processes and CD86 expression. Furthermore, CD3+, CD4+ or CD8+ cells were more frequently found in C6-CD200S tumors, and the expression of DC markers, granzyme, and perforin was increased in C6-CD200S tumors. Isolated TAMs from original C6 tumors were co-cultured with C6-CD200S cells and showed increased expression of DC markers. These results suggest that CD200S activates TAMs to become DC-like antigen presenting cells, leading to the activation of CD8+ cytotoxic T lymphocytes, which induce apoptotic elimination of tumor cells. The findings on CD200S action may provide a novel therapeutic modality for the treatment of carcinomas.

Uhrf1 is indispensable for normal limb growth by regulating chondrocyte differentiation through specific gene expression

ABSTRACT Transcriptional regulation can be tightly orchestrated by epigenetic regulators. Among these, ubiquitin-like with PHD and RING finger domains 1 (Uhrf1) is reported to have diverse epigenetic functions, including regulation of DNA methylation. However, the physiological functions of Uhrf1 in skeletal tissues remain unclear. Here, we show that limb mesenchymal cell-specific Uhrf1 conditional knockout mice (Uhrf1ΔLimb/ΔLimb) exhibit remarkably shortened long bones that have morphological deformities due to dysregulated chondrocyte differentiation and proliferation. RNA-seq performed on primary cultured chondrocytes obtained from Uhrf1ΔLimb/ΔLimb mice showed abnormal chondrocyte differentiation. In addition, integrative analyses using RNA-seq and MBD-seq revealed that Uhrf1 deficiency decreased genome-wide DNA methylation and increased gene expression through reduced DNA methylation in the promoter regions of 28 genes, including Hspb1, which is reported to be an IL1-related gene and to affect chondrocyte differentiation. Hspb1 knockdown in cKO chondrocytes can normalize abnormal expression of genes involved in chondrocyte differentiation, such as Mmp13. These results indicate that Uhrf1 governs cell type-specific transcriptional regulation by controlling the genome-wide DNA methylation status and regulating consequent cell differentiation and skeletal maturation. Summary: Integrative analyses using Uhrf1ΔLimb/ΔLimb mice and genome-wide sequencing reveal that Uhrf1 alters genome-wide DNA methylation status and, in turn, expression of specific genes, and is indispensable for normal limb growth.