[Pre-surgical diagnosis of neuroendocrine carcinoma of the extrahepatic bile duct: a case study].

A 70-year-old woman presented to our hospital with jaundice. Abdominal ultrasonography showed biliary duct dilatation. Blood tests revealed elevated total bilirubin and hepatobiliary enzyme levels. A contrast-enhanced computed tomography of the abdomen showed bile duct thickening with wall enhancement. Transpapillary bile duct biopsy showed an invasive carcinoma proliferating in a follicular pattern. Pathology revealed positive synaptophysin and chromogranin A and a Ki67 index >40%, consistent with a diagnosis of neuroendocrine carcinoma (NEC). After confirming the absence of distant metastases, a subtotal stomach-preserving pancreaticoduodenectomy was performed. The result of the postoperative pathology was the same as the preoperative biopsy. According to previous reports, 7 out of 28 cases with NEC/mixed adenoneuroendocrine carcinoma could be diagnosed as NEC before surgery. However, biliary cytology and bile duct scraping cytology were used in many cases;only 11 cases underwent bile duct biopsy. For the latter, 5 out of 11 cases could be diagnosed preoperatively. NEC of the extrahepatic duct often exhibits a submucosal tumor-like morphology, which may result in a false negative result with biliary cytology or bile duct scraping cytology. In our case, the transpapillary bile duct biopsy sample was sufficient to diagnose NEC. This method could be an attractive option for the diagnosis of these tumors.

Synthesis and biological evaluation of histone deacetylase and DNA topoisomerase II-Targeted inhibitors.

HDAC inhibitors enable histones to maintain a high degree of acetylation. The resulting looser state of chromatin DNA may increase the accessibility of DNA drug targets and consequently improve the efficiency of anticancer drugs targeting DNA, such as Topo II inhibitors. A novel class of nucleoside-SAHA derivatives has been designed and synthesized based on the synergistic antitumor effects of topoisomerase II and histone deacetylase inhibitors. Their inhibitory activities toward histone deacetylases and Topo II, and their cytotoxicities in cancer cell lines, were evaluated. Among the synthesized hybrid compounds, compound 16b showed the potent HDAC inhibitory activity at a low nanomolar level and exhibited antiproliferative activity toward cancer cell lines including MCF-7 (breast), HCT-116 (colon), and DU-145 (prostate) cancer cells at a low micromolar level. Moreover, compound 16a showed HDAC6-selectivity 20-fold over HDAC1.

Design, synthesis, and evaluation of DNA topoisomerase II-targeted nucleosides.

We developed novel nucleoside-based topoisomerase II selective inhibitors and showed that small structural units, such as catechols, are essential for DNA topoisomerase II inhibitory activity. Moreover, nucleoside analogues containing TBS and 1,3-dithian moieties had potent and selective DNA topoisomerase II inhibitory activities. In further experiments, compound 25b having a beta configuration of the thymine moiety showed relatively strong growth inhibitory activity against cancer cell lines, and was more potent against all cancer cell lines than compound 26b, which carries a thymine moiety in the alpha configuration.