Hideaki Naoe

LATS1/WARTS phosphorylates MYPT1 to counteract PLK1 and regulate mammalian mitotic progression

Showing convergence with budding yeast mitotic exit network signaling, the LATS1/WARTS kinase phosphorylates the MYPT1 phosphatase to control PLK1 at the G2 DNA damage checkpoint.

The Anaphase-Promoting Complex/Cyclosome Activator Cdh1 Modulates Rho GTPase by Targeting p190 RhoGAP for Degradation

ABSTRACT Cdh1 is an activator of the anaphase-promoting complex/cyclosome and contributes to mitotic exit and G1 maintenance by targeting cell cycle proteins for degradation. However, Cdh1 is expressed and active in postmitotic or quiescent cells, suggesting that it has functions other than cell cycle control. Here, we found that homozygous Cdh1 gene-trapped (Cdh1GT/GT) mouse embryonic fibroblasts (MEFs) and Cdh1-depleted HeLa cells reduced stress fiber formation significantly. The GTP-bound active Rho protein was apparently decreased in the Cdh1-depleted cells. The p190 protein, a major GTPase-activating protein for Rho, accumulated both in Cdh1GT/GT MEFs and in Cdh1-knockdown HeLa cells. Cdh1 formed a physical complex with p190 and stimulated the efficient ubiquitination of p190, both in in vitro and in vivo. The motility of Cdh1-depleted HeLa cells was impaired; however, codepletion of p190 rescued the migration activity of these cells. Moreover, Cdh1GT/GT embryos exhibited phenotypes similar to those observed for Rho-associated kinase I and II knockout mice: eyelid closure delay and disruptive architecture with frequent thrombus formation in the placental labyrinth layer, respectively. Furthermore, the p190 protein accumulated in the Cdh1GT/GT embryonic tissues. Our data revealed a novel function for Cdh1 as a regulator of Rho and provided insights into the role of Cdh1 in cell cytoskeleton organization and cell motility.

Brain metastasis from gastrointestinal stromal tumor: a case report and review of the literature.

Metastasis of gastrointestinal stromal tumor (GIST) into the central nervous system is extremely rare. We report a patient with synchronous GIST and brain metastasis. At disease onset, there was left hemiplegia and ptosis of the right eyelids. Resection cytology of the brain tumor was reported as metastasis of GIST. After positron emission tomography examination, another tumor in the small bowel was discovered, which suggested a small bowel GIST associated with intracranial metastasis. Immunohistochemical analysis of the intestinal tumor specimen obtained by double balloon endoscopy showed a pattern similar to the brain tumor, with the tumors subsequently identified as intracranial metastases of jejunal GIST. After surgical resection of one brain tumor, the patient underwent whole brain radiation therapy followed by treatment with imatinib mesylate (Gleevec; Novartis Pharma, Basel, Switzerland). Mutational analysis of the original intestinal tumor revealed there were no gene alterations in KIT or PDGFRα. Since the results indicated the treatment had no apparent effect on either of the tumors, and because ileus developed due to an intestinal primary tumor, the patient underwent surgical resection of the intestinal lesion. However, the patient’s condition gradually worsen and she subsequently died 4 months after the initial treatment.

Establishment of a choriocarcinoma model from immortalized normal extravillous trophoblast cells transduced with HRASV12.

Gestational choriocarcinoma is a malignant trophoblastic tumor. The development of novel molecular-targeted therapies is needed to reduce the toxicity of current multiagent chemotherapy and to treat successfully the chemoresistant cases. The molecular mechanisms underlying choriocarcinoma tumorigenesis remain uncharacterized, however, and appropriate choriocarcinoma animal models have not yet been developed. In this study, we established a choriocarcinoma model by inoculating mice with induced-choriocarcinoma cell-1 (iC³-1) cells, generated from HTR8/SVneo human trophoblastic cells retrovirally transduced with activated H-RAS (HRASV12). The iC³-1 cells exhibited constitutive activation of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways and developed into lethal tumors in all inoculated mice. Histopathological analysis revealed that the tumors consisted of two distinct types of cells, reminiscent of syncytiotrophoblasts and cytotrophoblasts, as seen in the human choriocarcinoma. The tumors expressed HLA-G and cytokeratin (trophoblast markers) and hCG (a choriocarcinoma marker). Comparative analysis of gene expression profiles between iC³-1 cells and parental HTR8/SVneo cells revealed that iC³-1 cells expressed matrix metalloproteinases, epithelial-mesenchymal transition-related genes, and SOX3 at higher levels than parental trophoblastic cells. Administration of SOX3-specific short-hairpin RNA decreased SOX3 expression and attenuated the tumorigenic activity of iC³-1 cells, suggesting that SOX3 overexpression might be critically involved in the pathogenesis of choriocarcinoma. Our murine model represents a potent new tool for studying the pathogenesis and treatment of choriocarcinoma.

Primary hepatic gastrinoma as an unusual manifestation of zollinger-ellison syndrome

We report a rare case of primary hepatic gastrinoma. A 77-year-old woman exhibited continuous watery diarrhea for 8 months and weight loss. Bacterial cultures of the stools were negative and colonoscopy revealed no abnormalities. Esophagogastroduodenoscopy showed severe reflux esophagitis and multiple duodenal erosions. Computed tomography and magnetic resonance imaging detected two solid masses measuring <2 cm in diameter in the right lobe of the non-cirrhotic liver. Microscopically, the tumor was consistent with neuroendocrine tumor (grade 2) with abundant gastrin-immunoreactive cells. Endoscopic ultrasound detected no other alternative primary source of an endocrine tumor. The serum gastrin levels exceeded 40,000 pg/ml in the absence of H2 receptor antagonist and proton pump inhibitor administrations. Based on an arterial stimulation and venous sampling test, the patient was diagnosed as primary gastrinoma of the liver. Our findings demonstrated the presence of Zollinger-Ellison syndrome in a patient who was subsequently cured by surgical resection of the liver tumors.

The cell cycle regulator Cdh1 controls the pool sizes of hematopoietic stem cells and mature lineage progenitors by protecting from genotoxic stress

Various key cell cycle components, especially G0/G1 regulators, have effects not only on cell proliferation but also on cell differentiation. Cdh1, one of the co‐activators that maintain anaphase‐promoting complex/cyclosome activity, plays a crucial role in the mitotic phase, but has recently been identified as a G0/G1 regulator, suggesting that the role of Cdh1 in cell differentiation. Here, we generated Cdh1 conditional gene‐trap mice to examine Cdh1 functions in adult tissues by overcoming the embryonic lethality of Cdh1 homozygous gene‐trap mice. We focused on the hematopoietic system and found that Cdh1‐deficient mice exhibited a general decrease in mature lineage progenitor cells and a significant increase in short‐term hematopoietic stem cells. This phenomenon became conspicuous by irradiation shortly after Cdh1 downregulation, suggesting that Cdh1 regulates the pool sizes of the hematopoietic stem cells and mature lineage progenitor cells by protecting cells from genotoxic stress. We also found that the irradiation‐induced G2/M checkpoint was defective in Cdh1‐deficient BM cells, causing the loss of stem/progenitor cells. This is the first report revealing Cdh1 function in adult hematopoiesis and showing a role of Cdh1 in a G2/M checkpoint regulation in vivo. (Cancer Sci 2011; 102: 967–974)

Pancreatic metastasis from mixed adenoneuroendocrine carcinoma of the uterine cervix: a case report.

Metastatic cancers of the pancreas are rare, accounting for approximately 2-4% of all pancreatic malignancies. Renal cell carcinoma is the most common solid tumor that metastasizes to the pancreas. Here, we present a case of uterine cervical carcinoma metastasizing to the pancreas and review the literature regarding this rare event. A 44-year-old woman with a uterine cervical tumor had undergone radical hysterectomy and had been diagnosed pathologically with stage Ib mixed adenoneuroendocrine carcinoma in 2004. She underwent concurrent radiotherapy and chemotherapy postoperatively. Pulmonary metastases subsequently appeared in 2008 and 2011, and she underwent complete resection of the lung tumors by video-assisted thoracic surgery. Although she was followed up without any treatment and with no other recurrences, positron emission tomography revealed an area of abnormal uptake within the pancreatic body in 2012. Enhanced computed tomography demonstrated a 20-mm lesion in the pancreatic body and upstream pancreatic duct dilatation. Endoscopic ultrasonography-guided fine needle aspiration was performed and pathological examination suggested neuroendocrine carcinoma (NEC). On the basis of these results and the patients oncological background, lesions in the pancreatic body were diagnosed as secondary metastasis from the cervical carcinoma that had been treated 8 years earlier. No other distant metastases were visualized, and the patient subsequently underwent middle pancreatectomy. Pathological examination showed NEC consistent with pancreatic metastasis from the uterine cervical carcinoma. The patient has survived 7 months since the middle pancreatectomy without any signs of local recurrence or other metastatic lesions.

A rare case showing subacute thyroiditis-like symptoms with amyloid goiter after anti-tumor necrosis factor therapy.

Summary Anti-tumor necrosis factor (TNF)-α therapy is established as a new standard for the treatment of various autoimmune inflammatory diseases. We report the first case showing subacute thyroiditis-like symptoms with an amyloid goiter after anti-TNF-α therapy. A 56-year-old man with Crohns disease presented with fever and a diffuse, tender goiter. To control the diarrhea, anti-TNF therapy (infliximab) was administered 4 weeks before the thyroid symptoms emerged. The patient reported a swollen neck with tenderness on the right side and fever 4 days after the second infliximab injection. An elevated serum C-reactive protein (CRP) and serum thyroid hormone level with suppressed serum thyrotropin were observed. The thyroid-stimulating antibody was not elevated. An ultrasonograph of the thyroid revealed an enlarged goiter with posterior echogenicity attenuation and a low echoic region that was tender. The thyroid uptake value on technetium-99m scintigraphy was near the lower limit of the normal range. The patient was initially diagnosed with thyrotoxicosis resulting from subacute thyroiditis. Administration of oral prednisolone improved the fever, thyroid pain, and thyroid function, but his thyroid remained swollen. The patient developed diarrhea after prednisolone withdrawal; therefore, adalimumab, another TNF inhibitor, was administered. After three injections, his abdominal symptoms were alleviated, but the thyroid pain and fever recurred. Elevated serum CRP levels in the absence of thyroid dysfunction were observed. The patients symptoms resolved after prednisolone retreatment, but an elastic, firm goiter persisted. A fine-needle biopsy revealed amyloid deposition in the thyroid. Learning points Many cases with thyroid dysfunction accompanied by amyloid goiter have been reported. There are cases that develop amyloid goiter with subacute thyroiditis-like symptoms after anti-TNF therapy. When the thyroid remains swollen after improvement of thyrotoxicosis following treatment with prednisolone, it should be assessed to differentiate between an amyloid goiter and common subacute thyroiditis.

The APC/C activator Cdh1 regulates the G2/M transition during differentiation of placental trophoblast stem cells.

Differentiation of placental trophoblast stem (TS) cells to trophoblast giant (TG) cells is accompanied by transition from a mitotic cell cycle to an endocycle. Here, we report that Cdh1, a regulator of the anaphase-promoting complex/cyclosome (APC/C), negatively regulates mitotic entry upon the mitotic/endocycle transition. TS cells derived from homozygous Cdh1 gene-trapped (Cdh1(GT/GT)) murine embryos accumulated mitotic cyclins and precociously entered mitosis after induction of TS cell differentiation, indicating that Cdh1 is required for the switch from mitosis to the endocycle. Furthermore, the Cdh1(GT/GT) TS cells and placenta showed aberrant expression of placental differentiation markers. These data highlight an important role of Cdh1 in the G2/M transition during placental differentiation.

Esophageal adenocarcinoma with enteroblastic differentiation arising in ectopic gastric mucosa in the cervical esophagus: A case report and literature review

BACKGROUND Adenocarcinoma with enteroblastic differentiation is a subtype of alpha-fetoprotein (AFP) producing adenocarcinoma. This type of tumor is associated with a poor prognosis and is prone to metastasize. Esophageal adenocarcinoma with enteroblastic differentiation is extremely rare. CASE PRESENTATION The patient was a 65-year-old woman who was referred to our hospital with dysphagia. Endoscopic examination revealed an elevated lesion 20mm in diameter at 17cm from the upper incisors. Endoscopic submucosa dissection (ESD) was performed and histopathological examination revealed tubular adenocarcinoma composed of cuboidal cells with clear cell cytoplasm. Immunohistochemical stain was diffusely positive for Sall-like protein 4 (SALL4) and weakly positive for AFP and glypican 3. From this result, we diagnosed esophageal adenocarcinoma with enteroblastic differentiation. The patient is still alive without recurrence of cancer 40 months after ESD. CONCLUSION To our knowledge, this is the first report to undergo ESD for esophageal adenocarcinoma with enteroblastic differentiation arising from ectopic gastric mucosa in the esophagus.