Kazunori Yawata

Extracellular signal-regulated kinase and Akt activation play a critical role in the process of hepatocyte growth factor-induced epithelial-mesenchymal transition.

Epithelial-mesenchymal transition (EMT) has recently been studied to elucidate mechanisms of the liver metastatic process. We investigated EMT in the process of liver metastasis and the effects of chemotherapy on EMT cells as therapeutic strategy for colorectal liver metastasis. We used the CT26 murine colorectal carcinoma cell line to create an in vivo mouse liver metastasis model. Liver tumors were stained immuno-histochemically. Expression of proteins associated with TGF-β/Smad and hepatocyte growth factor (HGF)/c-Met pathways were investigated by western blotting. Cells with c-Met mRNA knockdown by siRNA techniques showed clearly reduced liver metastases compared with regular cells at 21 days. TGF-β and HGF induced EMT expression, but signal transduction was quite different. TGF-β induced ERK, but not Akt phosphory-lation. HGF mediated both ERK and Akt phosphorylation. Akt inhibitor blocked Akt phosphorylation but did not affect TGF-β-induced activation of ERK, Snail and Slug. U-0126 did not reduce Snail activity by TGF-β at a concentration to block ERK phosphorylation. However, Akt inhibitor and U-0126 completely inhibited HGF-induced Slug activation. 5-FU mediated cell death in the EMT process induced by TGF-β more effectively than HGF. ERK/Akt signaling, but not the Smad pathway, may be one of the main processes in HGF-induced EMT, despite the Smad pathway, but not ERK/Akt, being critical for TGF-β-induced EMT. The MAPK/Akt pathway is indispensable in HGF/c-Met signaling. The ERK/Akt pathway particularly may be critical in the HGF-induced EMT process. However, long-term use of chemotherapeutic agents may induce drug resistance and distant metastases through EMT-related signaling pathway activation.

Decreased FANCJ caused by 5FU contributes to the increased sensitivity to oxaliplatin in gastric cancer cells

BackgroundOxaliplatin is effective against many types of cancer, and the combination of 5-fluorouracil (5FU) and oxaliplatin is synergistically effective against gastric cancer, as well as colon cancer. The FANCJ protein is one of the Fanconi anemia (FA) gene products, and its interaction with the tumor suppressor BRCA1 is required for DNA double-strand break (DSB) repair. FANCJ also functions in interstrand crosslinks (ICLs) repair by linking to mismatch repair protein complex MLH1-PMS2 (MutLα). While oxaliplatin causes ICLs, 5FU is considered to cause DSBs. Therefore, we investigated the importance of FANCJ in the synergistic effects of oxaliplatin and 5FU in MKN45 gastric cancer cells and the derived 5FU-resistant cell line, MKN45/F2R.MethodsMKN1, TMK1, MKN45, and MKN45/F2R (5FU-resistant) gastric cancer cells were treated with 5FU and/or oxaliplatin. The signaling pathway was evaluated by a western blotting analysis and reverse transcription polymerase chain reaction (RT-PCR). Drug resistance was evaluated by the 3-(4,5-dimethyl-2-tetrazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay.ResultsIn MKN45 cells, the combination of 5FU and oxaliplatin had synergistic effects. DSBs appeared when the cells were treated with 5FU. FANCJ was down-regulated, and BRCA1 was induced in a dose- and time-dependent manner. MKN45 cells showed increased sensitivity to oxaliplatin when FANCJ was knocked down by short interfering (si) RNA. However, these findings were not observed in MKN45/F2R 5FU-resistant cells.ConclusionThese results strongly suggest that the decrease in FANCJ caused by 5FU treatment leads to an increase in sensitivity to oxaliplatin, thus indicating that the FANCJ protein plays an important role in the synergism of the combination of 5FU and oxaliplatin.

A Single Case of Single-Port Access Laparoscopic Appendectomy During the Puerperium

Laparoscopic appendectomy is now widely practiced for the treatment of acute appendicitis. As result of increased demand for minimally invasive surgery, single-incision access was introduced and is being performed in various abdominal surgeries. Conventional laparoscopic appendectomy (LA) is gradually being performed in pregnant women. A 33-year-old woman was referred to our department at 39 weeks and 1 day of gestation due to abdominal pain. She was aware of her gastroepiploic pain even after the delivery. Though it was past 2 days, she was not recovering from right lower abdominal pain, so she was transferred to the Department of Gynecology at our hospital on the same day. Although an antibiotic was administered, the right abdominal pain did not improve, and she was referred to our department from the Department of Gynecology. We performed single-port LA (SP-LA). The total operation time was 63 minutes, and the estimated blood loss was 0 mL. She was discharged with no complications on postoperative day 7. We report our initial experience with single-port LA (SP-LA) using the glove technique for treatment of acute appendicitis in a postpartum woman. SP-LA using the glove technique was performed successfully during the puerperium without prolongation of operation time. This approach is less invasive, offers a much better cosmetic result than with conventional methods, and can be performed safely and at low cost.