Shuntaro Nagai

Lipopolysaccharide (LPS) increases the invasive ability of pancreatic cancer cells through the TLR4/MyD88 signaling pathway†

Inflammation plays a multifaceted role in cancer progression, and NF‐κB is one of the key factors connecting inflammation with cancer progression. We have shown that lipopolysaccharide (LPS) promotes NF‐κB activation in colon cancer cells and pancreatic cancer cells. However, it is unclear why inflammatory stimuli can induce NF‐κB activation in cancer cells.

γ-Secretase Inhibitors Enhance Taxane-Induced Mitotic Arrest and Apoptosis in Colon Cancer Cells

BACKGROUND & AIMS Colorectal cancers are resistant to conventional chemotherapeutic treatments, including taxanes. gamma-Secretase is a multimeric membrane protein complex responsible for the intramembrane proteolysis of various type I transmembrane proteins, including amyloid beta-precursor protein and Notch. gamma-Secretase inhibitors have attracted increasing interest as anticancer drugs because of their ability to inhibit Notch signaling. However, the therapeutic usefulness of gamma-secretase inhibitors against colorectal cancers remains unclear. METHODS The effects of gamma-secretase inhibitors on growth and apoptosis induced by various chemotherapeutic agents in colon cancer cells were evaluated using Hoechst 33342 staining, colony formation assay, and cell cycle analysis. The effect of gamma-secretase inhibitors on taxane-induced mitotic arrest was evaluated using the cyclin B1-associated histone H1 kinase assay and MPM-2 reactivity. The involvement of Notch signaling was evaluated by the silencing of Notch/CBF1 signaling by RNA interference. RESULTS gamma-Secretase inhibitors enhanced taxane-induced mitotic arrest and apoptosis of colon cancer cells both in vitro and in vivo, although gamma-secretase inhibitors alone did not affect growth and apoptosis of colon cancer cells. We also showed that this effect by gamma-secretase inhibitors was restricted to taxanes and colon cancer cells. Silencing of Notch/CBF1 signaling failed to affect paclitaxel-induced mitotic arrest and apoptosis. CONCLUSIONS These data suggest that gamma-secretase inhibitors could be a new therapeutic modality for overcoming resistance to taxanes in colorectal cancers.

Gli1 contributes to the invasiveness of pancreatic cancer through matrix metalloproteinase‐9 activation

The hedgehog (Hh) signaling pathway has been reported to be associated with the growth of pancreatic cancer, but its role in the invasive phenotype is poorly understood. Therefore, we investigated the role of the Hh pathway in pancreatic cancer cell invasiveness using a Matrigel invasion assay. Blockade of the Hh pathway by cyclopamine inhibited pancreatic cancer cell invasion in association with a decreased expression of matrix metalloproteinase (MMP)‐9. By contrast, activation of the Hh pathway by the addition of exogenous Sonic hedgehog increased cell invasion and MMP‐9 expression. Stable transfection of pancreatic cancer cells with Gli1 increased their invasiveness, which was associated with activation of MMP‐9. We also showed that inhibition of MMP‐9 by small interfering RNA blocked the increased invasiveness of Gli1‐transfected cells. Furthermore, inhibition of Gli1 by small interfering RNA suppressed the invasiveness and MMP‐9 expression of pancreatic cancer cells. Taken together, these findings suggest that members of the Hh pathway, especially Gli1, play an important role in the invasiveness of pancreatic cancer cells through the regulation of MMP‐9 expression. (Cancer Sci 2008; 99: 1377–1384)

Crosstalk of hedgehog and Wnt pathways in gastric cancer

Morphogenic signals like Hedgehog (Hh) and Wnt are reported to play critical roles in the progression of gastric cancer. We aimed to assess the relationship between Hh and Wnt signaling pathways. In 58 gastric cancer specimens, Wnt pathway activation was inversely correlated with Hh pathway activation. When AGS gastric cancer cells, in which Wnt signaling was constitutively active, were used as a target cell line, Gli1 overexpression suppressed Wnt transcriptional activity, nuclear beta-catenin accumulation and proliferation of AGS cells. Knock-down of beta-catenin by siRNA suppressed Wnt pathway activity and proliferation of AGS cells. Our data may provide some clues for the treatment of gastric cancer associated with Wnt signaling activation.

Feasibility of laparoscopic surgery for complex Crohn's disease of the small intestine

The laparoscopic approach for complex Crohns disease (CD), which involves abscess formation, fistula formation, and recurrent CD, is controversial. The aim of this study was to investigate the feasibility and safety of the laparoscopic approach for complex CD.

Efficacy and safety analysis of chemotherapy for advanced colitis-associated colorectal cancer in Japan.

Chemotherapy for advanced colitis-associated colorectal cancer (CAC) has been insufficiently evaluated. The goal of this study was to clarify the efficacy and safety of chemotherapy for CAC in Japan. CAC patients who were treated with chemotherapy between 2005 and 2015 were retrospectively examined. Twenty-nine patients (median age, 48 years; 23 men) were assessed. Eighteen patients had ulcerative colitis, and 11 had Crohn’s disease. Three ulcerative colitis and four Crohn’s disease patients were in the active disease phase. Primary tumors were located in the rectum/anus (n=16), the left colon (n=9), or the right colon (n=4). Palliative or adjuvant chemotherapy was performed in 13 and 16 patients, respectively. First-line palliative chemotherapy regimens were as follows: fluorouracil, leucovorin, and oxaliplatin (FOLFOX; n=6), FOLFOX+bevacizumab (n=3), and others (n=4). Adjuvant chemotherapy regimens were S-1 (n=7), oxaliplatin-based (n=4) and others (n=5). In palliative chemotherapy, the objective response rate was 15%, and the median progression-free survival and overall survival were 182 and 315 days, respectively. In adjuvant chemotherapy, the 5-year relapse-free survival rate was 78%. Grade 3/4 adverse events (AEs) were observed in 16 patients (55%). Active and remission inflammatory bowel disease patients suffered grade 3/4 nonhematological AEs at an incidence of 71 and 23%, respectively (P<0.01). Dose reduction was required in 11 patients (38%), eight of whom required it for hematological AEs. Adjuvant chemotherapy for CAC exhibited sufficient efficacy, whereas modest efficacy was shown for palliative chemotherapy for CAC. AEs, particularly nonhematological AEs, were closely associated with disease activity of colitis.

Application of ultrasonography to high-tie and low-tie vascular ligation of the inferior mesenteric artery in laparoscopic colorectal cancer surgery: technical notes

BackgroundTwo ligation techniques can be applied in laparoscopy for left-sided colorectal cancer: (1) high-tie (HT), transection at the level of the inferior mesenteric artery (IMA); and (2) low-tie (LT), transection below the IMA, at the level of superior rectal artery (SRA), preserving the left colic artery (LCA). However, even with preoperative images, it can still be a challenge to identify these structures due to intraoperative individual conditions. In this study, we assess the use intraoperative ultrasonography (IOUS) to aid us in identifying the IMA and its branches to the SRA, LCA, and sigmoid artery.MethodsWe performed IOUS in 18 patients diagnosed with left-sided colorectal cancer. Preoperatively, a three-dimensional computed tomography (3D-CT) angiography was obtained in majority of the patients, to visualize the IMA and its branches. Two patients were contraindicated to receive a contrast study, hence, was unable to undergo 3D-CT angiography. The resected specimen was grossly examined for the study. The bifurcation types were identified and compared using different modalities: preoperative 3D-CT, IOUS, and gross examination of the resected specimen.ResultsThe branching of the IMA revealed by IOUS was consistent to the findings preoperatively by the 3D-CT and postoperatively by the resected specimen. The IOUS result of the two patients without preoperative 3D-CT evaluation was also consistent with the post-operative bifurcation type.ConclusionsIOUS is an easy and feasible modality which aids in detecting the branching of the IMA during LT and HT ligation in laparoscopic left-sided colorectal surgery. It can serve as an adjunct modality for 3D-CT angiography and can also be considered a safe alternative option for cases wherein 3D-CT angiography is unavailable.

Effect of age factors on health-related quality of life in patients with lower rectal cancer after sphincter-saving surgery: A 1-year longitudinal study

PURPOSE To examine age-related factors influencing health-related quality of life (HR-QOL) among patients with lower rectal cancer during the 12-month period after sphincter-saving surgery (SSS). MATERIAL AND METHODS In this 1-year longitudinal study, 137 patients (120 patients completed, and 82 aged ≥60 years) answered the European Organization for Research and Treatment of Cancer questionnaire (EORTC-C30/CR38) assessing their HR-QOL and related factors during the 12 months after SSS. RESULTS No significant differences in HR-QOL were found before surgery. Only among those aged ≥60 years, global health status/QOL and cognitive functioning showed a significant decrease one month after surgery. At one month after SSS, the role functioning of groups <60 years old (which is negatively related to defecation problems, insomnia, and financial difficulties) was lower compared to those aged ≥60 years; and role functioning was significantly related to global health status/QOL. Six months after SSS, the global health status/QOL had recovered. In both groups, global health status/QOL was related to role and social functioning. Among participants aged <60 years, global health status/QOL was significantly related to emotional functioning, which is related to future perspective. Among participants aged ≥60 years only, global health status/QOL was significantly related to cognitive functioning; pain, financial difficulties, and defecation problems negatively influenced HR-QOL. Symptoms specific after SSS: defecation problems (in both group), micturition problems (only ≥60 years), and sexual problems (only<60 years) influenced HR-QOL. CONCLUSION Health care providers should assess the influence of age-related factors during the early post-operative period after SSS to improve HR-QOL.

RBPJ and MAML3: Potential therapeutic targets for small cell lung cancer

Background/Aim: Small cell lung cancer (SCLC) is still a deadly type of cancer for which there are few effective therapeutic strategies. Development of a new molecule targeting agent is urgently desired. Previously we showed that recombination signal binding protein for immunoglobulin-kappa-J region (RBPJ) and mastermind-like 3 (MAML3) are new therapeutic targets for pancreatic cancer. In the present study, we analyzed whether RBPJ/MAML3 inhibition could also be a new therapeutic strategy for SCLC. Materials and Methods: Using silencing of RBPJ/MAML3, proliferation, invasion, migration and chemosensitivity of SBC-5 cells were investigated. Results: RBPJ/MAML3 inhibition reduced Smoothened and HES1 expression, suggesting that RBPJ/MAML3 signaling was through Hedgehog and NOTCH pathways. In the analysis of cell functions, RBPJ/MAML3 inhibition significantly reduced proliferation and invasiveness via reduction of expression of matrix metalloproteinases. On the other hand, RBPJ/MAML3 inhibition also reduced chemosensitivity to cis-diamminedichlo-roplatinum and gemcitabine. Conclusion: These results suggest that RBPJ and MAML3 could be new therapeutic targets for SCLC, however, chemosensitivity may be reduced in combinational use with other chemo-therapeutic agents.

Laparoscopic excision of neurogenic retrorectal tumors

Retrorectal tumors (RT) are uncommon and usually managed by open surgical excision. Laparoscopic excision for RT has been reported in only a small number of papers. We aimed to assess the laparoscopic approach for RT and to discuss the factors that made this procedure difficult. We performed laparoscopic excision using a five‐trocar technique for neurogenic RT in three patients. Tumors were successfully excised laparoscopically in two patients. However, the third patient required open conversion because the tumor was strongly adhered to the sacrum and could not be mobilized by dissection, resulting in poor visualization of the dissected site. Laparoscopic excision for RT provides excellent intraoperative visualization and good cosmesis in selected patients, but firm adherence to the sacrum may cause difficulty with this procedure.