Yasutaka Matsunaga

HER2 expression and PI3K-Akt pathway alterations in gastric cancer.

The anti-HER2 antibody trastuzumab has led to an era of personalized therapy in gastric cancer (GC). As a result, HER2 expression has become a major concern in GC. HER2 overexpression is seen in 7-34% of GC cases. Trastuzumab is an antibody that targets the HER2 extracellular domain and induces antibody-dependent cellular cytotoxicity and inhibition of the HER2 downstream signals. Mechanisms of resistance to trastuzumab have been reported in breast cancer. There are various mechanisms underlying trastuzumab resistance, such as alterations of HER2 structure or surroundings, dysregulation of HER2 downstream signal effectors and interaction of HER2 with other membrane receptors. The PI3K-Akt pathway is one of the main downstream signaling pathways of HER2. It is well known that PIK3CA mutations and phosphate and tensin homolog (PTEN) inactivation cause over-activation of the downstream signal without an upstream signal activation. Frequencies of PIK3CA mutations and PTEN inactivation have been reported to be 4-25 and 16-77%, respectively. However, little is known about the association between HER2 expression and PI3K-Akt pathway alterations in GC. We have found that HER2 over-expression was significantly correlated with pAkt expression in GC tissues. Furthermore, pAkt expression was correlated with poor prognosis. These results suggest that the PI3K-Akt pathway plays an important role in HER2-positive GC. Moreover, PIK3CA mutations and/or PTEN inactivation might affect the effectiveness of HER2-targeting therapy. Hence, it is necessary to clarify not only HER2 alterations but also PI3K-Akt pathway alterations for HER2-targeting therapy in GC. This review will introduce recent investigations and consider the current status of HER2-targeted therapy for treatment of GC.

The effect of IGF-I receptor blockade for human esophageal squamous cell carcinoma and adenocarcinoma

Insulin-like growth factor-I receptor (IGF-IR) signaling is required for carcinogenicity and tumor development, and this pathway has not been well studied in human esophageal carcinomas. Esophageal cancer is one of the human cancers with the worst prognosis and has two main histologies: squamous cell carcinomas (ESCC) and adenocarcinoma (EAC). Previously, we have reported that detection of the IGF axis may be useful for the prediction of recurrence and poor prognosis of ESCC. We have also shown the successful therapy for several gastrointestinal cancers using recombinant adenoviruses expressing dominant negative IGF-IR (ad-IGF-IR/dn). The aim of this study is to develop potential targeted therapeutics to IGF-IR and to assess the effect of IGF-IR blockade in both of these types of esophageal cancer. We determined immunohistochemical expression of IGF-IR in a tissue microarray. We then assessed the effect of IGF-IR blockade on signal transduction, proliferation, apoptosis, and motility. Ad-IGF-IR/dn, a tyrosine kinase inhibitor, BMS-536924, and adenovirus expressing shRNA for IGF-IR were used. IGF-IR expression was common in both tumor types but not in normal tissues. IGF-IR was detected in metastatic sites at similar levels compared to the primary site. IGF-IR inhibition suppressed proliferation and colony formation in both cancers. IGF-IR blockades up-regulated both stress- and chemotherapy-induced apoptosis and reduced migration. Although IGF-IR/dn blocked ligand-induced activation of Akt-1 mainly, BMS-536924 effectively blocked both activation of Akt and MAPK. The IGF axis might play a key role in tumor progression of esophageal carcinomas. The IGF-IR targeting strategies might thus be useful anticancer therapeutics for human esophageal malignancies.

The effect of forced expression of mutated K-RAS gene on gastrointestinal cancer cell lines and the IGF-1R targeting therapy.

Mutation in K‐RAS (K‐RAS‐MT) plays important roles in both cancer progression and resistance to anti‐epidermal growth factor receptor (EGFR) therapy in gastrointestinal tumors. Insulin‐like growth factor‐1 receptor (IGF‐1R) signaling is required for carcinogenicity and progression of many tumors as well. We have previously shown successful therapy for gastrointestinal cancer cell lines bearing a K‐RAS mutation using an anti‐IGF‐1R monoclonal antibody. In this study, we sought to evaluate effects of forced K‐RAS‐MT expression on gastrointestinal cancer cell lines representing a possible second resistance mechanism for anti‐EGFR therapy and IGF‐1R‐targeted therapy for these transfectants. We made stable transfectants of K‐RAS‐MT in two gastrointestinal cancer cell lines, colorectal RKO and pancreatic BxPC‐3. We assessed the effect of forced expression of K‐RAS‐MT on proliferation, apoptosis, migration, and invasion in gastrointestinal cancer cells. Then we assessed anti‐tumor effects of dominant negative IGF‐1R (IGF‐1R/dn) and an IGF‐1R inhibitor, picropodophyllin, on the K‐RAS‐MT transfectants. Overexpression of K‐RAS‐MT in gastrointestinal cancer cell lines led to more aggressive phenotypes, with increased proliferation, decreased apoptosis, and increased motility and invasion. IGF‐1R blockade suppressed cell growth, colony formation, migration, and invasion, and up‐regulated chemotherapy‐induced apoptosis of gastrointestinal cancer cells, even when K‐RAS‐MT was over‐expressed. IGF‐1R blockade inhibited the Akt pathway more than the extracellular signal‐regulated kinase (ERK) pathway in the K‐RAS‐MT transfectants. IGF‐1R/dn, moreover, inhibited the growth of murine xenografts expressing K‐RAS‐MT. Thus, K‐RAS‐MT might be important for progressive phonotype observed in gastrointestinal cancers. IGF‐1R decoy is a candidate molecular therapeutic approach for gastrointestinal cancers even if K‐RAS is mutated.

Extensive portal and mesenteric vein thrombosis in a young man with Klinefelter's syndrome

Klinefelters syndrome (KS) is a unique physical condition characterized by tall stature, eunuchoid body proportions, gynecomastia, and azoospermia, in addition to an extra X chromosome. In contrast to the original description, symptoms or physical findings can be extremely varied. KS is the most common chromosomal disorder, with an incidence of 1 in 500 males and is also the most commonly undiagnosed chromosomal disorder. Here, we present the case of a 26‐year‐old man with KS, who visited our hospital with complaints of abdominal pain and fever. On a routine physical examination, he did not differ from a normal karyotype male. Computed tomography showed extensive portal and mesenteric vein thrombosis (PMVT). It is well known that KS is frequently associated with venous thrombosis, but KS with PMVT has rarely been reported. Approximately one‐third of PMVT is idiopathic, but this case suggests the possibility that undiagnosed KS is one of the causes of PMVT, as some individuals with KS are not easily distinguishable from those with the normal karyotype.

Abstract 4306: Free IGFBP3 and the risk of liver cancer in a nested case-control study

Background: Insulin-like growth factor-1 (IGF1) is a potent mitogen, whereas IGF-binding protein-3 (IGFBP3) binds and inhibits IGF1. High circulating IGF1 and low IGFBP3 are associated with increased risk of several cancers. Here we examined relations of those serum levels with the risk of hepatoma in a prospective case-control study nested in the JACC Study. Methods: A baseline survey was conducted from 1988 to 1990 and 39,242 subjects donated blood samples. Those who had been diagnosed as hepatoma were regarded as cases for nested case-control studies. Ninety-one cases and 263 controls are eligible for the present analysis. A conditional logistic model was used to estimate odds ratios (OR) for incidence of hepatoma associated with serum IGF1 and IGFBP3 levels. Results: Both IGF1 and molar ratio of IGF1/IGFBP3 were not correlated with the risk of hepatoma. After adjustment for hepatitis-viral infection, body mass index, smoking, and alcohol intake, higher molar difference of (IGFBP3 - IGF1) was associated with decreased risk of hepatoma (p for trend Conclusions: Molar difference of (IGFBP3 - IGF1) might associate inversely with the incidence of hepatoma. Citation Format: Yasushi Adachi, Masanori Nojima, Mitsuru Mori, Yasutaka Matsunaga, Noriyuki Akutsu, Shigeru Sasaki, Takao Endo, Youichi Kurozawa, Kenji Wakai, Akiko Tamakoshi. Free IGFBP3 and the risk of liver cancer in a nested case-control study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4306.

Abstract 3474: The effect of forced expression of k-ras mutation on gastrointestinal cancer cells and IGF-IR targeting therapy

Background & Aims: Mutation in k-ras plays important roles in both the progression and the resistance for anti-EGFR therapy in gastrointestinal tumors. Insulin-like growth factor-I receptor (IGF-IR) signaling is required for carcinogenicity and proliferation of many tumors. We have previously shown successful therapy for gastrointestinal cancer cell lines with k-ras mutation using recombinant adenoviruses expressing dominant negative IGF-IR (IGF-IR/dn) and an anti-IGF-IR monoclonal antibody. In this study, we sought to evaluate the effect of k-ras mutation on gastrointestinal cancer cell lines and IGF-IR targeting therapies for those cells. Methods: We made stable transfectants of mutated k-ras in gastrointestinal cancer cell lines. We assessed the effect of forced expression of mutated k-ras on proliferartion, apoptosis induction, migration, and invasion in gastrointestinal cancer cell lines. Then we assessed the anti-tumor effect of IGF-IR/dn on mutated k-ras transfctomas. Results: Overexpression of mutated k-ras let gastrointestinal cancer cell lines be more agrressive phenotypes, such as more proliferative, more anti-apoptotic, more movable, and more invasive. IGF-IR/dn inhibited cell growth, colony formation, migration, and invasion, but induceed apoptosis of gastrointestinal cancer cells with or without mutated k-ras expression. Conclusions: K-ras mutation might be inportant for progressive phonotype in gastrointestinal cancers. IGF-IR might be a good molecular therapeutic target for gastrointestinal cancers even if k-ras is mutated. Citation Format: Yasushi Adachi, Yasutaka Matsunaga, Yasushi Sasaki, Katsuhiko Nosho, Hiroyuki Yamamoto, Yoshiaki Arimura, Takao Endo, Yasuo Kato, Takashi Tokino, David P. Carbone, Yasuhisa Shinomura. The effect of forced expression of k-ras mutation on gastrointestinal cancer cells and IGF-IR targeting therapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3474. doi:10.1158/1538-7445.AM2015-3474

Abstract 609: Targeting IGF-I receptor for hepatocellular carcinoma

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Aims; Hepatocellular carcinoma (HCC) is one of worse prognostic diseases. Insulin-like growth factor (IGF)-I receptor (IGF-IR) signaling is required for carcinogenicity and tumor development of many malignancies and is thought to be a next molecular target. We have previously shown successful therapy for gastrointestinal carcinomas, including colon, stomach, esophageal, pancreatic, and biliary tract cancers, using recombinant adenoviruses expressing dominant negative IGF-IR (IGF-IR/dn). In this study, we want to assess the roles of IGF axis on HCC and to develop potential targeted therapeutics for HCC. Methods; We assessed mRNA expressions of IGFs and those receptors in HCC cell lines. We assessed the effect of IGF-IR blockade on signal-transduction, growth, apoptosis-induction, and migration. To block IGF signals, we used IGF-IR/dn, short hairpin RNA, monoclonal antibody, and tyrosin kinase inhibitor for IGF-IR. Results; IGF-I messages expressed in 63%, IGF-II mRNA in 44%, and IGF-IR in 89% of HCC cell lines. All IGF-IR blockades suppressed significantly both in vitro cell growth and colony formation. Each anti-IGF-IR up-regulated both stressor- and chemotherapy-induced apoptosis. IGF-IR inhibitor down-regulated cell migration. IGF-IR targeting strategies effectively blocked ligands induced receptor activation and the downstream signals. Conclusions; IGF axis might play a key role in tumor progression of human HCC. Every strategy to block IGF-IR shows a useful anticancer therapeutic for HCC, indicating that IGF-IR may be a candidate molecular target for HCC. Citation Format: Yasushi Adachi, Yasutaka Matsunaga, Hiroyuki Yamamoto, Katsuhiko Nosho, Hiromu Suzuki, Yoshiaki Arimura, Takao Endo, Yasuo Kato, David P. Carbone, Yasuhisa Shinomura. Targeting IGF-I receptor for hepatocellular carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 609. doi:10.1158/1538-7445.AM2014-609

Abstract 867: IGF-I receptor targeting therapy for esophageal carcinomas.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Insulin-like growth factor (IGF)-I receptor (IGF-IR) signaling is required for tumorigenicity and cancer development of many malignancies, however this pathway has not been well studied in human esophageal carcinomas. Esophageal cancer is one of worst prognostic disease, main types of which are squamous cell carcinomas (ESCC) and adenocarcinoma (EAC). Previously we have reported that the IGF axis may play a key role in tumor progression of ESCC and its detection may be useful for the prediction of recurrence and poor prognosis and possibly for selecting patients for targeting therapy for IGF-IR. We have previously shown successful therapy for several gastrointestinal cancers using recombinant adenoviruses expressing dominant negative forms of IGF-IR (Ad-IGF-IR/dn). In this study, we wanted to develop potential targeted therapeutics to IGF-1R; therefore, we assessed the effect of IGF-IR blockade in both types of esophageal cancer. We analyzed immunohistochemical expression of IGF-IR in a tissue array. A tyrosine kinase inhibitor, BMS-536924, and Ad-IGF-IR/dn were used to treat several ESCC lines, such as TE1, TE8, TT, TTn, and EAC lines, including OE19 and OE33. We assessed the effect of both IGF-IR blockade on signal transduction, growth, and apoptosis. IGF-IR is expressed frequently in esophageal tumors, but not in normal mucosa. IGF-IR was produced in ESCC more than EAC, and is detected in metastasized similar to the primary site. IGF-IR inhibition suppressed proliferation and colony formation in both types of cancer. Blockade of IGF-IR up-regulated both stress- and chemotherapy-induced apoptosis in both esophageal tumor type. Although IGF-IR/dn blocked ligand-induced activation of Akt-1 mainly, BMS-536924 effectively blocked both activation of Akt and MAPK. Thus, the IGF axis may play a key role in tumor progression of human esophageal carcinomas. The IGF-IR targeting strategies might be useful anticancer therapeutics which can be used widely for human esophageal malignancies. Citation Format: Yasushi Adachi, Hiroyuki Yamamoto, Hirokazu Ohashi, Yasutaka Matsunaga, Katsuhiko Nosho, Hiromu Suzuki, Hiroaki Taniguchi, Yoshiaki Arimura, Takao Endo, Yasuo Kato, Kohzoh Imai, David P. Carbone, Yasushisa Shinomura. IGF-I receptor targeting therapy for esophageal carcinomas. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 867. doi:10.1158/1538-7445.AM2013-867