Involvement of Lgl and Mahjong/VprBP in Cell Competition

Mahjong is a novel Lethal giant larvae-binding protein that plays a vital role in cell competition in both flies and mammals

転写因子Sp3は肉腫転移関連マーカーAFAP1L1の発現を制御する

京都大学0048新制・課程博士博士(医学)甲第17780号医博第3806号新制||医||999(附属図書館)30587京都大学大学院医学研究科医学専攻(主査)教授 妻木 範行, 教授 武藤 学, 教授 松田 道行学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

A role of the sphingosine-1-phosphate (S1P)-S1P receptor 2 pathway in epithelial defense against cancer (EDAC)

At the initial step of carcinogenesis, transformation occurs in single cells within epithelia, where the newly emerging transformed cells are surrounded by normal epithelial cells. A recent study revealed that normal epithelial cells have an ability to sense and actively eliminate the neighboring transformed cells, a process named epithelial defense against cancer (EDAC). However, the molecular mechanism of this tumor-suppressive activity is largely unknown. In this study, we investigated a role for the sphingosine-1-phosphate (S1P)-S1P receptor 2 (S1PR2) pathway in EDAC. First, we show that addition of the S1PR2 inhibitor significantly suppresses apical extrusion of RasV12-transformed cells that are surrounded by normal cells. In addition, knockdown of S1PR2 in normal cells induces the same effect, indicating that S1PR2 in the surrounding normal cells plays a positive role in the apical elimination of the transformed cells. Of importance, not endogenous S1P but exogenous S1P is involved in this process. By using FRET analyses, we demonstrate that S1PR2 mediates Rho activation in normal cells neighboring RasV12-transformed cells, thereby promoting accumulation of filamin, a crucial regulator of EDAC. Collectively these data indicate that S1P is a key extrinsic factor that affects the outcome of cell competition between normal and transformed epithelial cells

Lung metastasis of ta bladder cancer: a case report and literature review.

A 66-year-old man with a history of multiple transurethral resections for recurrent bladder tumors, staged as Ta according to the International Union Against Cancer staging guidelines, presented with a complaint of dry cough. A round nodule with a diameter of 7.5 cm was detected in the lung by chest computed tomography, and a video-assisted thoracoscopic lobectomy was performed. Pulmonary metastasis of recurrent bladder cancer was diagnosed by immunohistochemistry staining for the urothelium-specific protein uroplakin Ia. Subsequently, 2 cycles of systemic chemotherapy were administered. Two and a half years after treatment, no recurrence of pulmonary lesions has been detected. A combination of complete resection of pulmonary lesions and systemic chemotherapy may result in a good prognosis for patients with non-muscle-invasive bladder cancer

Calcium Wave Promotes Cell Extrusion

When oncogenic transformation or apoptosis occurs within epithelia, the harmful or dead cells are apically extruded from tissues to maintain epithelial homeostasis. However, the underlying molecular mechanism still remains elusive. In this study, we first show, using mammalian cultured epithelial cells and zebrafish embryos, that prior to apical extrusion of RasV12-transformed cells, calcium wave occurs from the transformed cell and propagates across the surrounding cells. The calcium wave then triggers and facilitates the process of extrusion. IP3 receptor, gap junction, and mechanosensitive calcium channel TRPC1 are involved in calcium wave. Calcium wave induces the polarized movement of the surrounding cells toward the extruding transformed cells. Furthermore, calcium wave facilitates apical extrusion, at least partly, by inducing actin rearrangement in the surrounding cells. Moreover, comparable calcium propagation also promotes apical extrusion of apoptotic cells. Thus, calcium wave is an evolutionarily conserved, general regulatory mechanism of cell extrusion

The transcription factor Sp3 regulates the expression of a metastasis-related marker of sarcoma, actin filament-associated protein 1-like 1 (AFAP1L1).

We previously identified actin filament-associated protein 1-like 1 (AFAP1L1) as a metastasis-predicting marker from the gene-expression profiles of 65 spindle cell sarcomas, and demonstrated the up-regulation of AFAP1L1 expression to be an independent risk factor for distant metastasis in multivariate analyses. Little is known, however, about how the expression of AFAP1L1 is regulated. Luciferase reporter assays showed tandem binding motives of a specificity protein (Sp) located at -85 to -75 relative to the transcriptional start site to be essential to the promoter activity. Overexpression of Sp1 and Sp3 proteins transactivated the proximal AFAP1L1 promoter construct, and electrophoretic mobility shift assays showed that both Sp1 and Sp3 were able to bind to this region in vitro. Chromatin immunoprecipitation experiments, however, revealed that Sp3 is the major factor binding to the proximal promoter region of the AFAP1L1 gene in AFAP1L1- positive cells. Treatment with mithramycin A, an inhibitor of proteins binding to GC-rich regions, prevented Sp3 from binding to the proximal promoter region of AFAP1L1 and decreased its expression in a dose-dependent manner. Finally, knocking down Sp3 using small inhibitory RNA duplex (siRNA) reduced AFAP1L1 expression significantly, which was partially restored by expressing siRNA-resistant Sp3. These findings indicate a novel role for Sp3 in sarcomas as a driver for expression of the metastasis-related gene AFAP1L1