A transmembrane glycoprotein, gp38, is a novel marker for immature hepatic progenitor cells in fetal mouse livers

Previously, we clarified the surface antigen profiles of hepatic progenitor cells (HPCs) in fetal liver tissue as the CD49f+CD45−Thy1− cell fraction. However, these cells were a heterogeneous cell population containing various stages of differentiation. This study aimed to detect more immature HPCs, using a novel surface antigen, gp38. After the collagenase digestion of fetal livers harvested from E13.5 to E18.5 fetal mice, HPCs were obtained and divided into two subpopulations using flow cytometry: gp38-positive HPCs, and gp38-negative HPCs. Both types of HPCs were characterized by immunocytochemistry and RT-PCR. The proliferative activity was compared by BrdU incorporation and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTS) assay. Furthermore, the comprehensive gene expression was investigated by DNA microarray. Both types of HPCs expressed alpha-fetoprotein. However, the gp38-positive HPCs derived from E13.5 fetal livers did not express albumin or cytokeratin 19, while the gp38-negative HPCs did. DNA microarray revealed that some genes related to the Wnt signal pathway were up-regulated in the gp38-positive HPCs. Furthermore, Wnt3a had a proliferative effect on the gp38-positive HPCs. In conclusion, the gp38-positive HPCs derived from fetal liver tissue until E13.5 could therefore be candidates for hepatic stem cells in the fetal liver

糖蛋白gp38は胎仔肝細胞における未分化肝前駆細胞の新規マーカーである

京都大学0048新制・課程博士博士(医学)甲第16311号医博第3601号新制||医||989(附属図書館)28928京都大学大学院医学研究科外科系専攻(主査)教授 千葉 勉, 教授 斎藤 通紀, 教授 坂井 義治学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDA

Prolines in the α-helix confer the structural flexibility and functional integrity of importin-β

The karyopherin family of nuclear transport receptors is composed of a long array of amphiphilic α-helices and undergoes flexible conformational changes to pass through the hydrophobic crowding barrier of the nuclear pore. Here, we focused on the characteristic enrichment of prolines in the middle of the outer α-helices of importin-β. When these prolines were substituted with alanine, nuclear transport activity was reduced drastically in vivo and in vitro, and caused a severe defect in mitotic progression. These mutations did not alter the overall folding of the helical repeat or affect its interaction with cargo or the regulatory factor Ran. However, in vitro and in silico analyses revealed that the mutant lost structural flexibility and could not undergo rapid conformational changes when transferring from a hydrophilic to hydrophobic environment or vice versa. These findings reveal the essential roles of prolines in ensuring the structural flexibility and functional integrity of karyopherins

Metastatic colorectal cancer responsive to regorafenib for 2 years: a case report

Abstract Background Regorafenib is an oral multikinase inhibitor that has been demonstrated as clinically effective in patients with metastatic colorectal cancer in phase III studies. Although disease control was achieved in 40% of the pretreated patients with metastatic colorectal cancer in the pivotal studies, radiological response has rarely been reported. Severe adverse events associated with regorafenib are known to occur during the first and second courses of treatment. We present a case of a 62-year-old Japanese patient whose metastatic colorectal cancer has been responding to treatment with regorafenib for 2 years. Case presentation A 54-year-old Japanese man visited our institute exhibiting general malaise, and he was diagnosed with ascending colon cancer in April 2006. He underwent right hemicolectomy, and the final staging was T3N0M0, stage II. After 19 months, pulmonary metastasis and anastomotic recurrences were detected, and a series of operations were performed to resect both metastatic lesions. After that, liver metastasis, a duodenal metastasis with right renal invasion, right adrenal metastasis, and para-aortic lymph node metastases were observed during follow-up, and chemotherapy and resection were performed. The patient had metastatic para-aortic lymph nodes after the fifth tumor resection and underwent multiple lines of chemotherapy in April 2014. Regorafenib monotherapy was started at 80 mg/day. Then, regorafenib was increased to 120 mg/day in the second cycle. Regorafenib monotherapy led to 60% tumor shrinkage within the initial 2 months, and the tumor further decreased in size over 4 months until it became unrecognizable on imaging studies. The clinical effects of regorafenib monotherapy have shown a partial response according to Response Evaluation Criteria in Solid Tumors criteria. No severe adverse events were observed, except for mild fatigue and hand-foot syndrome. The patient has received 24 courses of regorafenib over 2 years without exhibiting tumor progression. Conclusions To the best of our knowledge, this is the longest treatment with regorafenib without tumor progression ever reported. A reduced dosage of regorafenib at induction may ameliorate the cutaneous and hepatic toxicity associated with its use