Targeting of MAPK-associated molecules identifies SON as a prime target to attenuate the proliferation and tumorigenicity of pancreatic cancer cells

Abstract Background Pancreatic cancer is characterized by constitutive activation of mitogen-activated protein kinase (MAPK). Activation of MAPK is associated with the upregulation of genes implicated in the proliferation and survival of pancreatic cancer cells. We hypothesized that knockdown of these MAPK-associated molecules could produce notable anticancer phenotypes. Methods A RNA interference-mediated knockdown screening of 78 MAPK-associated molecules previously identified was performed to find molecules specifically associated with proliferation of pancreatic cancer cells in vitro. Expression of an identified molecule in pancreatic cancer tissues was examined by immunohistochemistry. In vivo tumorigenicity of cancer cells with stable knockdown of the molecule was assayed by using xenograft models. Flow cytometry and live cell imaging were employed to assess an association of the molecule with cell cycle. Results The knockdown screening revealed that knockdown of SON, the gene encoding SON, which is a large serine/arginine-rich protein involved in RNA processing, substantially suppressed pancreatic cancer cell proliferation and survival in vitro and tumorigenicity in vivo. SON expression was higher in ductal adenocarcinomas than in cells of normal ducts and precursor lesions in pancreatic cancer tissues. Knockdown of SON induced G2/M arrest and apoptosis in cultured cancer cells. The suppressive effect of SON knockdown on proliferation was less pronounced in cultured normal duct epithelial cells. SON formed nuclear speckles in the interphase of the cell cycle and dispersed in the cytoplasm during mitosis. Live cell imaging showed that SON diffusely dispersed in the early mitotic phase, accumulated in some foci in the cytoplasm in the late mitotic phase, and gradually reassembled into speckles after mitosis. Conclusion These results indicate that SON plays a critical role in the proliferation, survival, and tumorigenicity of pancreatic cancer cells, suggesting that SON is a novel therapeutic molecular target for pancreatic cancer.</p

A case of small-cell esophageal cancer with chronic renal failure undergoing hemodialysis safely treated with cisplatin and etoposide

A 54-year-old male undergoing hemodialysis was admitted to our hospital because of difficulty in swallowing. Esophagography and esophageal endoscopy revealed an irregular ulcerated lesion in the cervical esophagus. It was diagnosed as a small-cell esophageal cancer from the biopsy sample. Computed tomography showed a tumor infiltrating the trachea and a few lymph node metastases in the cervix, upper mediastinum, and abdomen. The patient was started on chemotherapy with cisplatin (CDDP) and etoposide (VP-16), which had been reported to be effective for small-cell lung cancer. The patient was treated with CDDP (80 mg/m2) on day 1 and VP-16 (100 mg/m2) on days 1, 3, and 5, every 4 weeks. On the days of chemotherapy, hemodialysis was started as soon as possible after completion of administration of the agents. No severe side effects were observed. After 4 courses of therapy, the patient achieved a partial response

A homosexual japanese man with acute hepatitis due to hepatitis B virus genotype ae, concurrent with amebic colitis

We report herein a case with acute hepatitis due to hepatitis B virus genotype Ae, concurrent with amebic colitis. A 39-year-old homosexual Japanese man was admitted to our hospital with jaundice. Laboratory tests showed an elevation of transaminase and positivity for hepatitis B surface antigen and IgM-type antibody to hepatitis B core antigen. The hepatitis B virus genotype was determined to be Ae. Furthermore, a mud-like stool with blood and mucous had sometimes been noted during the past 3 years, and amebic colitis was shown by colonofi berscopy during hospitalization. The patient was diagnosed with acute hepatitis B, concurrent with amebic colitis, and was successfully treated with lamivudine and metronidazole. In Japanese patients with acute hepatitis B virus genotype A infection, homosexual activity tends to be high. Furthermore, in Japanese homosexual men, amebiasis has been increasing. Thus, in Japanese patients with acute hepatitis B, a determination of genotype should be performed in order to investigate the route of transmission of hepatitis B virus, and a search for amebiasis should be performed in patients with acute hepatitis due to hepatitis B virus genotype A. Furthermore, education of homosexual men regarding hepatitis B virus, hepatitis B virus vaccination, and amebiasis is urgently required

Improvement of titanium wettability by hydrogen peroxide processing using an LED polymerizer

When titanium is immersed in hydrogen peroxide solution, an oxidation film is formed on itʼs surface. In this study, to investigate the influence of film–forming methods in order to clarify the relationship with wettability, the film was created by immersing titanium in a hydrogen peroxide solution, and by irradiating the immersed titanium with Light emitting diode (LED) light. The following results were obtained: The wettability of test specimens immersed in the hydrogen peroxide solution improved, in comparison with that before immersion. However, no significant differences were noted among the treatment times. The wettability of test specimens immersed in the hydrogen peroxide solution and irradiated with LED light promptly improved. This depends on the resolution of the differential temperature caused by irradiation or on hydrogen peroxide immersion in the presence of light. There is a possibility that the titanium surface can be reformed easily and rapidly by immersing titanium in hydrogen peroxide solution and applying visible LED light