Satoshi Matsukuma

Effects of retinoic acids on the dendritic morphology of cultured hippocampal neurons

Vitamin A‐derived retinoic acids (RAs) are known to exert a variety of biological actions, including modulatory effects on cell differentiation and apoptosis. A recent study has demonstrated that 13‐cis‐RA and all‐trans‐RA suppressed neurogenesis in the dentate gyrus of the hippocampus in adult mice. The present experiments were performed to see whether 13‐cis‐RA and all‐trans‐RA could alter the dendritic morphology of cultured hippocampal neurons via RA receptors: retinoic acid receptor (RAR) and retinoid X receptor (RXR). High doses of 13‐cis‐RA and all‐trans‐RA exerted a negative effect on the cultured hippocampal neurons, while a low dose of 13‐cis‐RA but not all‐trans‐RA caused a positive effect. The negative changes induced by 13‐cis‐RA and all‐trans‐RA were antagonized by RXR antagonists and RAR antagonists, respectively. The positive changes induced by a low dose of 13‐cis‐RA were blocked by both RXR antagonists and RAR antagonists. These results suggest that RAs at high concentrations cause a negative effect on the dendritic morphology of cultured hippocampal neurons through RA receptors, while RAs at low concentrations exert a positive influence on cultured hippocampal neurons.

An accurate prognostic staging system for hepatocellular carcinoma patients after curative hepatectomy

The aim of this study was to develop an accurate predictive system for prognosis of hepatocellular carcinoma (HCC) patients after hepatectomy. We pooled data of clinicopathological features of 234 HCC patients who underwent curative hepatectomy. On the basis of the pooled data, we established a simple predictive staging system (PS score) scored by the mathematical product of tumor number and size, and degree of liver function. We compared the prognostic abilities of the PS score (score 0–3) with those of six well-known clinical staging systems. Then, we found that there were significant differences (P<0.05) in both disease-free survival (DFS) and overall survival (OS) between patients with different PS scores (PS score 0 vs. 1; PS score 1 vs. 2), and there was a significant difference in DFS, but not OS, between patients with PS score 2 and those with PS score 3. Moreover, the PS score had smaller values of the Akaike information criterion for both DFS and OS than any of the six well-known clinical staging systems. These results suggest that the PS score serves as a simple, accurate predictor for the prognosis of HCC patients after hepatectomy.

Metastatic ability and the epithelial‐mesenchymal transition in induced cancer stem‐like hepatoma cells

Cancer stem cells (CSCs) are thought to play important roles in cancer malignancy. Previously, we successfully induced sphere cancer stem‐like cells (CSLCs) from several cell lines and observed the property of chemoresistance. In the present study, we examined the metastatic potential of these induced CSLCs. Sphere cancer stem‐like cells were induced from a human hepatoma cell line (SK‐HEP‐1) in a unique medium containing neural survival factor‐1. Splenic injection of cells into immune‐deficient mice was used to assess hematogenous liver metastasis. Transcriptomic strand‐specific RNA‐sequencing analysis, quantitative real‐time PCR, and flow cytometry were carried out to examine the expression of epithelial‐mesenchymal transition (EMT)‐related genes. Splenic injection of CSLCs resulted in a significantly increased frequency of liver metastasis compared to parental cancer cells (P < .05). In CSLCs, a mesenchymal marker, Vimentin, and EMT‐promoting transcription factors, Snail and Twist1, were upregulated compared to parental cells. Correspondingly, significant enrichment of the molecular signature of the EMT in CSLCs relative to parental cancer cells was shown (q < 0.01) by RNA‐sequencing analysis. This analysis also revealed differential expression of CD44 isoforms between CSLCs and parental cancer cells. Increasing CD44 isoforms containing an extra exon were observed, and the standard CD44 isoform decreased in CSLCs compared to parental cells. Interestingly, another CD44 variant isoform encoding a short cytoplasmic tail was also upregulated in CSLCs (11.7‐fold). Our induced CSLCs possess an increased liver metastatic potential in which promotion of the EMT and upregulation of CD44 variant isoforms, especially short‐tail, were observed.

Postoperative Adjuvant Therapy for Resectable Pancreatic Cancer With Gemcitabine and Adoptive Immunotherapy

Objectives We previously described adoptive immunotherapy (AIT) with cytotoxic T lymphocytes (CTLs) stimulated by the mucin 1 (MUC1)–expressing human pancreatic cancer cell line YPK-1 (MUC1-CTLs) and demonstrated that MUC1-CTLs might prevent liver metastasis. In the present study, we combined gemcitabine (GEM) and AIT for the treatment of pancreatic cancer. Methods A total of 43 patients who underwent radical pancreatectomy received treatment with MUC1-CTLs and GEM. After surgery, MUC1-CTLs were induced and administered intravenously 3 times, and GEM administered according to the standard regimen for 6 months. The patients whose relative dose intensity of GEM was 50% or more and who received 2 or more MUC1-CTL treatments were used as the adequate treatment group (n = 21). Results In the adequate treatment group, disease-free survival was 15.8 months, and overall survival was 24.7 months. Liver metastasis was found only in 7 patients (33%), and local recurrence occurred in 4 patients (19%). The independent prognostic factor of long-term disease-free survival on multivariate analysis was the average number of CTLs administered (P = 0.0133). Conclusions The combination therapy with AIT and GEM prevented liver metastasis and local recurrence. Moreover, the disease free-survival was improved in patients who received sufficient CTLs.

Expression levels of UL16 binding protein 1 and natural killer group 2 member D affect overall survival in patients with gastric cancer following gastrectomy

UL16 binding protein 1 (ULBP1) expressed on the tumor cell surface binds to the natural killer group 2 member D (NKG2D) receptor presenting on natural killer (NK), cluster of differentiation (CD)8+ T, and γ δ T cells. However, the roles of ULBP1 and NKG2D expression and associated immune responses in gastric cancer are unclear. The present study investigated the associations between ULBP1 and NKG2D expression and clinical outcomes in patients with gastric cancer. The levels of ULBP1 and NKG2D expression were examined in human gastric cancer cell lines and gastric cancer tissues from 98 patients who underwent surgery from 2004 to 2008. MKN-74 cells expressed ULBP1 with ULBP2, −5, or −6. NKG2D was expressed at a higher level following activation of T cells and NK cells. Among the tissue sections positive for NKG2D expression, 6 patients were positive for CD8 and CD56. In all tissues, NKG2D-expressing cells were typically aCD8+ T cells. Patients with NKG2D expression in tumors exhibited significantly longer overall survival (OS) compared with patients without NKG2D expression in tumors (P=0.0217). The longest OS was observed in patients positive for ULBP1 and NKG2D, whereas the shortest OS was observed in patients negative for ULBP1 and NKG2D. The interaction between ULBP1 and NKG2D may improve OS in patients with gastric cancer, and may have applications in immunotherapy for the induction of adaptive immunity in patients with cancer. Additionally, ULBP1 and NKG2D may be useful as prognostic biomarkers in gastric cancer.

A new prognostic model for hepatocellular carcinoma recurrence after curative hepatectomy

We previously reported the effectiveness of the product of tumor number and size (NxS factor) for the prognosis of hepatocellular carcinoma (HCC) in patients following hepatectomy. The present study aimed to propose a new score based on the NxS factor to predict HCC recurrence following hepatectomy. A total of 406 patients who underwent hepatectomy for HCC at Osaka University Graduate School of Medicine were retrospectively analyzed to develop the new score. Among clinicopathological factors, including the NxS factor, the marker subset that achieved the best performance for prediction of early recurrence was assessed, and a prognostic model for HCC recurrence after curative hepatectomy (REACH) was developed. As the validation set, 425 patients who underwent hepatectomy for HCC at Yamaguchi University Graduate School of Medicine and Shimonoseki Medical Center were analyzed, and the prognostic ability of the REACH score was compared with that of well-known staging systems. Following analysis, the REACH score was constructed using six covariates (NxS factor, microscopic hepatic vein invasion, differentiation, serum albumin, platelet count and indocyanine green retention rate at 15 min). In the validation set, the REACH score predicted early recurrence in 73 of 81 samples, with a sensitivity of 89% and a specificity of 58%. The area under the curve (AUC) of the receiver operating characteristic curve of the REACH score was 0.78 and 0.74, respectively, for 1- and 2-year recurrence after hepatectomy; each AUC was higher than that of any of the other staging systems. Survival analysis indicated the REACH score had the best predictive value in disease-free and overall survival. The present findings demonstrated that the REACH score may be used to classify patients with HCC into high- and low-risk of recurrence, and to predict subsequent survival following hepatic resection.

Outcomes following liver resection for multinodular Barcelona Clinic Liver Cancer‑B hepatocellular carcinoma

Management of multinodular hepatocellular carcinoma (HCC) in the intermediate Barcelona Clinic Liver Cancer (BCLC)-B stage is controversial. The aim of the present study as to identify the subgroup of patients with BCLC-B HCC who could benefit from liver resection. The present study retrospectively analyzed the outcomes of 65 patients (training cohort) who underwent liver resection for multinodular BCLC-B HCC. Coxs regression analysis was conducted to identify the independent prognostic factors for overall survival and to develop the prognostic score. As some authors have reported that maximum tumor size (cm) plus tumor number (N+S) is a prognostic factor in patients with BCLC-B HCC who undergo chemoembolization, the usefulness of this factor in patients who underwent liver resection was also evaluated. Subsequently, the validity of the prognostic score was assessed in an independent validation cohort (n=132). Multivariate analysis revealed that positivity for hepatitis C virus antibody (HCV-ab), platelet count ≤1010/l, N+S >8, and des-γ-carboxy prothrombin (DCP) >400 mAU/ml were independent prognostic factors for overall survival. The prognostic score differentiated two groups (≤2, ≥3) with distinct outcomes (median survival time 68.3 months vs. 29.1 months; P<0.0001). This result was confirmed in an external validation cohort. Therefore, surgery can promote long-term survival in patients with multinodular HCC although the indications for surgery are limited. HCV-Ab status, preoperative platelet count, DCP level and N+S may be useful for patient selection.

Abstract 1927: The significance of calreticulin in pancreatic cancer: a molecule highly expressed in pancreatic cancer stem-like cells

Cancer stem-like cells (CSLCs) in solid tumors are thought to be resistant to conventional chemotherapy or molecular targeting therapy and to contribute to cancer recurrence and metastasis. In this study, we aimed to identify a biomarker of pancreatic CSLCs (P-CSLCs). P-CSLC-enriched population was generated from pancreatic cancer cell lines using our previously reported method and its protein expression profile was compared with that of parental cells by two-dimensional electrophoresis and tandem mass spectrometry. The results indicated that a chaperone protein calreticulin (CRT) was significantly upregulated in P-CSLCs compared to parental cells. Flow cytometry analysis demonstrated that CRT was mostly localized to the surface of P-CSLCs and did not correlate with the levels of CD44v9, another P-CSLC biomarker. Furthermore, the side population in CRThigh/CD44v9low population is much higher than that in CRTlow/CD44v9high population. CRT expression was also assessed by immunohistochemistry in pancreatic cancer tissues (n = 80) obtained after radical resection and was found to be associated with patients’ clinicopathological features and disease outcomes in the Cox’s proportional hazard regression model. Multivariate analysis identified CRT as an independent prognostic factor for pancreatic cancer patients, along with age and post-operative therapy. Our results suggest that CRT can serve as a biomarker of P-CSLCs and a prognostic factor associated with poorer survival of pancreatic cancer patients. This novel biomarker can be useful for detecting P-CSLCs independently, which had been detectable by multiple surface markers like CD24, CD44 and ESA. We will present CSLCs properties of CRThigh population in P-CSLCs. Citation Format: Satoshi Matsukuma, Kiyoshi Yoshimura, Atsunori Oga, Moeko Inoue, Takuya Fujimtoto, Atsuo Kuramasu, Masanori Fuse, Ryouichi Tsunedomi, Hidetoshi Eguchi, Hiroto Matsui, Shinsuke Kanekiyo, Yukio Tokumitsu, Shinobu Tomochika, Michihisa Iida, Yoshihiro Tokuhisa, Kazuhiko Sakamoto, Nobuaki Suzuki, Tomoko Furuya-Kondo, Hiroshi Itoh, Shigeru Takeda, Shigeru Yamamoto, Shigefumi Yoshino, Shoichi Hazama, Tomio Ueno, Hiroaki Nagano. The significance of calreticulin in pancreatic cancer: a molecule highly expressed in pancreatic cancer stem-like cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1927. doi:10.1158/1538-7445.AM2017-1927