Combination therapy with WEE1 inhibition and trifluridine/tipiracil against esophageal squamous cell carcinoma

Despite advanced therapeutics, esophageal squamous cell carcinoma (ESCC) remains one of the deadliest cancers. Here, we propose a novel therapeutic strategy based on synthetic lethality combining trifluridine/tipiracil and MK1775 (WEE1 inhibitor) as a treatment for ESCC. This study demonstrates that trifluridine induces single-strand DNA damage in ESCC cells, as evidenced by phosphorylated replication protein 32. The DNA damage response includes cyclin-dependent kinase 1 (CDK1) (Tyr15) phosphorylation as CDK1 inhibition and a decrease of the proportion of phospho-histone H3 (p-hH3)-positive cells, indicating cell cycle arrest at the G2 phase before mitosis entry. The WEE1 inhibitor remarkedly suppressed CDK1 phosphorylation (Try15) and reactivated CDK1, and also increased the proportion of p-hH3-positive cells, which indicates an increase of the number of cells into mitosis. Trifluridine combined with a WEE1 inhibitor increased trifluridine-mediated DNA damage, namely DNA double-strand breaks, as shown by increased γ-H2AX expression. Moreover, the combination treatment with trifluridine/tipiracil and a WEE1 inhibitor significantly suppressed tumor growth of ESCC-derived xenograft models. Hence, our novel combination treatment with trifluridine/tipiracil and a WEE1 inhibitor is considered a candidate treatment strategy for ESCC.

Abstract 6187: The combination of Trifluridine/Tipiracil and a WEE1 inhibitor is an effective and tolerable candidate strategy against ESCC

Background: Recently we reported that trifluridine (FTD)/Tipiracil (TPI) is tolerable for unresectable Esophageal squamous cell carcinoma (ESCC) patients although the anti-tumor effect was modest (Mori Y, et al. Esophagus 2022). Therefore, we aimed at developing a combination therapy with FTD/TPI with another small molecule to achieve better efficacy against ESCC. CHK1 inhibitor was considered to be the candidate, because combination treatment with FTD/TPI and prexasertib showed potent antitumor effects in p53-mutant ESCC cells through the synthetic lethality (Ohashi S, et al. Mol Cancer Ther 2020); however, CHK1 inhibitors are not clinically available for further clinical development. Here we explored the concept of synthetic lethality with CHK1 perturbation to the whole ATR-CHK1-WEE1 pathway, especially to the downward WEE1 which directly targets a cell cycle regulator CDK1. The aim of this study is to elucidate the efficacy of the combination of a WEE1 inhibitor (WEE1i) MK1775 with FTD/TPI in ESCC.

Methods: ESCC cells (TE-8 and TE-11) are used for in vitro assay, with compounds including FTD, MK1775 (WEE1i). Mitosis assay (flowcytometry with phospho-Histone H3 [p-hH3] antibody), cell viability assay (WST-1 and clonogenic assays), cytotoxicity assay (CytoTox-Glo assay), and western blotting (double-strand DNA break [γ-H2AX], DDR activity [phospho-CHK1], and CDK1 activity [phospho-Tyr15-CDK1]) were performed. Antitumor effects and tolerability were observed in vivo with TE-8 xenograft model with nu/nu nude mice.

Results: FTD induced activation of CHK1 and inhibition of CDK1 sequentially in ESCC cells. FTD also decreased the proportion of p-hH3 positive cells in mitosis assay. Combination treatment with WEE1i and FTD had activated CDK1, increased p-hH3 positive cells, and induced γ-H2AX. The WST-1 cell viability assay showed significant sensitizing effect of WEE1i to FTD in ESCC cells. The cytotoxicity assay also revealed the significant increase of dead cells by the combination treatment (p = 0.003). Furthermore, we confirmed the combination treatment significantly suppressed xenografted tumor growth (-86%) without major adverse events in vivo (two-way ANOVA and Tukey post-hoc analyses: FTD/TPI vs. control, P < 0.05; MK1775 vs. control, P < 0.05, without significant interaction between the FTD/TPI treatment and MK1775 treatment).

Conclusion: FTD/TPI and WEE1i combination showed potent cytotoxicity, and is considered as a candidate treatment strategy against ESCC.

Citation Format: Hoang Trang Nguyen Vu, Osamu Kikuchi, Tomoki Saito, Yukie Nakai, Tomomi Ida, Yuki Kondo, Shigeki Kataoka, Yosuke Mitani, Shinya Ohashi, Manabu Muto. The combination of Trifluridine/Tipiracil and a WEE1 inhibitor is an effective and tolerable candidate strategy against ESCC. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6187.

Targeting activin receptor-like kinase 7 ameliorates adiposity and associated metabolic disorders

Activin receptor-like kinase 7 (ALK7) is a type I receptor in the TGF-β superfamily preferentially expressed in adipose tissue and associated with lipid metabolism. Inactivation of ALK7 signaling in mice results in increased lipolysis and resistance to both genetic and diet-induced obesity. Human genetic studies have recently revealed an association between ALK7 variants and both reduced waist to hip ratios and resistance to development of diabetes. In the present study, treatment with a neutralizing mAb against ALK7 caused a substantial loss of adipose mass and improved glucose intolerance and insulin resistance in both genetic and diet-induced mouse obesity models. The enhanced lipolysis increased fatty acid supply from adipocytes to promote fatty acid oxidation in muscle and oxygen consumption at the whole-body level. The treatment temporarily increased hepatic triglyceride levels, which resolved with long-term Ab treatment. Blocking of ALK7 signals also decreased production of its ligand, growth differentiation factor 3, by downregulating S100A8/A9 release from adipocytes and, subsequently, IL-1β release from adipose tissue macrophages. These findings support the feasibility of potential therapeutics targeting ALK7 as a treatment for obesity and diabetes.

Developing SHP2-based combination therapy for KRAS-amplified cancer

Gastroesophageal adenocarcinomas (GEAs) harbor recurrent amplification of KRAS, leading to marked overexpression of WT KRAS protein. We previously demonstrated that SHP2 phosphatase, which acts to promote KRAS and downstream MAPK pathway activation, is a target in these tumors when combined with MEK inhibition. We hypothesized that SHP2 inhibitors may serve as a foundation for developing novel combination inhibitor strategies for therapy of KRAS-amplified GEA, including with targets outside the MAPK pathway. Here, we explore potential targets to effectively augment the efficacy of SHP2 inhibition, starting with genome-wide CRISPR screens in KRAS-amplified GEA cell lines with and without SHP2 inhibition. We identify candidate targets within the MAPK pathway and among upstream RTKs that may enhance SHP2 efficacy in KRAS-amplified GEA. Additional in vitro and in vivo experiments demonstrated the potent cytotoxicity of pan-ERBB kinase inhibitions in vitro and in vivo. Furthermore, beyond targets within the MAPK pathway, we demonstrate that inhibition of CDK4/6 combines potently with SHP2 inhibition in KRAS-amplified GEA, with greater efficacy of this combination in KRAS-amplified, compared with KRAS-mutant, tumors. These results suggest therapeutic combinations for clinical study in KRAS-amplified GEAs.

Impaired CD4+ T cell response in older adults is associated with reduced immunogenicity and reactogenicity of mRNA COVID-19 vaccination

Whether age-associated defects in T cells impact the immunogenicity and reactogenicity of mRNA vaccines remains unclear. Using a vaccinated cohort (n = 216), we demonstrated that older adults (aged ≥65 years) had fewer vaccine-induced spike-specific CD4⁺ T cells including CXCR3⁺ circulating follicular helper T cells and the T_H1 subset of helper T cells after the first dose, which correlated with their lower peak IgG levels and fewer systemic adverse effects after the second dose, compared with younger adults. Moreover, spike-specific T_H1 cells in older adults expressed higher levels of programmed cell death protein 1, a negative regulator of T cell activation, which was associated with low spike-specific CD8⁺ T cell responses. Thus, an inefficient CD4⁺ T cell response after the first dose may reduce the production of helper T cytokines, even after the second dose, thereby lowering humoral and cellular immunity and reducing systemic reactogenicity. Therefore, enhancing CD4⁺ T cell response following the first dose is key to improving vaccine efficacy in older adults.

Pharmacologic characterization of TBP1901, a prodrug form of aglycone curcumin, and CRISPR-Cas9 screen for therapeutic targets of aglycone curcumin

Curcumin (aglycone curcumin) has antitumor properties in a variety of malignancies via the alteration of multiple cancer-related biological pathways; however, its clinical application has been hampered due to its poor bioavailability. To overcome this limitation, we have developed a synthesized curcumin β-D-glucuronide sodium salt (TBP1901), a prodrug form of aglycone curcumin. In this study, we aimed to clarify the pharmacologic characteristics of TBP1901. In β-glucuronidase (GUSB)-proficient mice, both curcumin β-D-glucuronide and its active metabolite, aglycone curcumin, were detected in the blood after TBP1901 injection, whereas only curcumin β-D-glucuronide was detected in GUSB-impaired mice, suggesting that GUSB plays a pivotal role in the conversion of TBP1901 into aglycone curcumin in vivo. TBP1901 itself had minimal antitumor effects in vitro, whereas it demonstrated significant antitumor effects in vivo. Genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screen disclosed the genes associated with NF-κB signaling pathway and mitochondria were among the highest hit. In vitro, aglycone curcumin inhibited NF-kappa B signaling pathways whereas it caused production of reactive oxygen species (ROS). ROS scavenger, N-acetyl-L-cysteine, partially reversed antitumor effects of aglycone curcumin. In summary, TBP1901 can exert antitumor effects as a prodrug of aglycone curcumin through GUSB-dependent activation.

Abstract 6377: Developing combination therapy with SHP2 inhibition for CIN-type gastroesophageal adenocarcinoma with KRAS amplification

Recent studies from the cancer genome atlas (TCGA. Nature. 2014) (TCGA. Nature. 2017) and other groups showed that a molecular subtype with chromosomal instability (CIN) is the most common subtype of gastroesophageal adenocarcinoma (GEA) and is characterized by aneuploidy without somatic hypermutation. The oncogene KRAS is frequently amplified in CIN type gastric cancer (14.3%) and esophageal adenocarcinoma (10.4%). SHP2 is a phosphatase which is a part of a machinery activating KRAS from GDP-bound inactive status to GTP-bound active status, and our group previously reported that KRAS-amplified gastric tumors are relatively resistant to MEK inhibition but sensitive to MEK/SHP2 co-inhibition. While the combination of MEK and SHP2 inhibitors showed efficacy in pre-clinical models, the translation of this combination has been challenging, in part due to on-target toxicity from inhibitors of the MAPK pathway (Auliac, et al. Cancers. 2020). Therefore, we sought better combination strategy with SHP2 inhibition, using genome-wide CRISPR screen. We conducted primary CRISPR screening with two GEA cell lines (KE-39 and HUG1-N) and CRISPR-KO lentivirus library (Brunello CRISPR knockout pooled library, 77,741 sgRNAs/19,114 genes, Broad Institute Genomic Perturbation Platform) and identified candidate targets both within the MAPK pathway and among upstream tyrosine kinases that may enhance the efficacy of a SHP2 inhibitor in KRAS-amplified GEA. Prior to detailed analyses of potential hits from the screen, we performed the secondary screen with additional KRAS-amplified and -mutant cell lines (CAT12, YCC-1, and GSU) using a custom CRISPR-Cas9 sgRNA library targeting 509 genes of interest including top hits in each cell line data set, and confirmed that knockout of KRAS upstream and downstream genes have additive cytotoxicity to SHP2 inhibition. Given our focus on finding targets that could be readily translated into therapeutics, we focused our analysis on those of most ready translational relevance and specifically chose ERBBs, FAK, SRC, RAFs, ERK1/2, and CDK4/6 as candidate targets. Further analyses showed the potent cytotoxicity of SHP2 inhibition with a pan-ERBB kinase inhibitior (Afatinib) and with a CDK4/6 inhibitor (Ribociclib), with greater efficacy of this combination in KRAS-amplified tumors compared to KRAS-mutant tumors, both in vitro and in vivo experiments. Overall, these results suggest co-inhibition of SHP2 and upstream/downstream of KRAS as a promising treatment strategy against KRAS-amplified CIN-type GEA.

Citation Format: Osamu Kikuchi, Tianxia Li, Jin Zhou, Yichen Wang, Klavdija Bastl, Prafulla C. Gokhale, Aine Knott, Yanxi Zhang, John G. Doench, Zandra Ho, Daniel V. Catenacci, Adam J. Bass. Developing combination therapy with SHP2 inhibition for CIN-type gastroesophageal adenocarcinoma with KRAS amplification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6377.

Protein Kinase C (Pkc)-δ Mediates Arginine-Induced Glucagon Secretion in Pancreatic α-Cells

The pathophysiology of type 2 diabetes involves insulin and glucagon. Protein kinase C (Pkc)-δ, a serine-threonine kinase, is ubiquitously expressed and involved in regulating cell death and proliferation. However, the role of Pkcδ in regulating glucagon secretion in pancreatic α-cells remains unclear. Therefore, this study aimed to elucidate the physiological role of Pkcδ in glucagon secretion from pancreatic α-cells. Glucagon secretions were investigated in Pkcδ-knockdown InR1G9 cells and pancreatic α-cell-specific Pkcδ-knockout (αPkcδKO) mice. Knockdown of Pkcδ in the glucagon-secreting cell line InR1G9 cells reduced glucagon secretion. The basic amino acid arginine enhances glucagon secretion via voltage-dependent calcium channels (VDCC). Furthermore, we showed that arginine increased Pkcδ phosphorylation at Thr505, which is critical for Pkcδ activation. Interestingly, the knockdown of Pkcδ in InR1G9 cells reduced arginine-induced glucagon secretion. Moreover, arginine-induced glucagon secretions were decreased in αPkcδKO mice and islets from αPkcδKO mice. Pkcδ is essential for arginine-induced glucagon secretion in pancreatic α-cells. Therefore, this study may contribute to the elucidation of the molecular mechanism of amino acid-induced glucagon secretion and the development of novel antidiabetic drugs targeting Pkcδ and glucagon.

[Research Support at the Clinical Bioresource Center in Kyoto University Hospital]

Biobanks are an essential platform for the development of medicine and healthcare. In biobanks, the quality of the biospecimens collected and stored and the quality and quantity of the clinical information associated with them are important. In addition, biobanks handle clinical information, so the management of personal information and the scope of consent are also important. On the other hand, if the collected biological samples are not utilized, they are meaningless. Therefore, it is also required to respond to various needs. In order to address these issues, we have established a hospital-based Clinical Bioresource Center(CBRC)and developed projects to promote the utilization of biospecimens. In this paper, we describe the CBRC at Kyoto University Hospital.

Disordered branched chain amino acid catabolism in pancreatic islets is associated with postprandial hypersecretion of glucagon in diabetic mice

Dysregulation of glucagon is associated with the pathophysiology of type 2 diabetes. We previously reported that postprandial hyperglucagonemia is more obvious than fasting hyperglucagonemia in type 2 diabetes patients. However, which nutrient stimulates glucagon secretion in the diabetic state and the underlying mechanism after nutrient intake are unclear. To answer these questions, we measured plasma glucagon levels in diabetic mice after oral administration of various nutrients. The effects of nutrients on glucagon secretion were assessed using islets isolated from diabetic mice and palmitate-treated islets. In addition, we analyzed the expression levels of branched chain amino acid (BCAA) catabolism-related enzymes and their metabolites in diabetic islets. We found that protein, but not carbohydrate or lipid, increased plasma glucagon levels in diabetic mice. Among amino acids, BCAAs, but not the other essential or nonessential amino acids, increased plasma glucagon levels. BCAAs also directly increased the intracellular calcium concentration in α cells. When BCAAs transport was suppressed by an inhibitor of system L-amino acid transporters, glucagon secretion was reduced even in the presence of BCAAs. We also found that the expression levels of BCAA catabolism-related enzymes and their metabolite contents were altered in diabetic islets and palmitate-treated islets compared to control islets, indicating disordered BCAA catabolism in diabetic islets. Furthermore, BCKDK inhibitor BT2 suppressed BCAA-induced hypersecretion of glucagon in diabetic islets and palmitate-treated islets. Taken together, postprandial hypersecretion of glucagon in the diabetic state is attributable to disordered BCAA catabolism in pancreatic islet cells.

Visceral fat obesity is the key risk factor for the development of reflux erosive esophagitis in 40-69-years subjects

BACKGROUND

Visceral fat obesity can be defined quantitatively by abdominal computed tomography, however, the usefulness of measuring visceral fat area to assess the etiology of gastrointestinal reflux disease has not been fully elucidated.

METHODS

A total of 433 healthy subjects aged 40-69 years (234 men, 199 women) were included in the study. The relationship between obesity-related factors (total fat area, visceral fat area, subcutaneous fat area, waist circumference, and body mass index) and the incidence of reflux erosive esophagitis was investigated. Lifestyle factors and stomach conditions relevant to the onset of erosive esophagitis were also analyzed.

RESULTS

The prevalence of reflux erosive esophagitis was 27.2% (118/433; 106 men, 12 women). Visceral fat area was higher in subjects with erosive esophagitis than in those without (116.6 cm² vs. 64.9 cm², respectively). The incidence of erosive esophagitis was higher in subjects with visceral fat obesity (visceral fat area ≥ 100 cm²) than in those without (61.2% vs. 12.8%, respectively). Visceral fat obesity had the highest odds ratio (OR) among obesity-related factors. Multivariate analysis showed that visceral fat area was associated with the incidence of erosive esophagitis (OR = 2.18), indicating that it is an independent risk factor for erosive esophagitis. In addition, daily alcohol intake (OR = 1.54), gastric atrophy open type (OR = 0.29), and never-smoking history (OR = 0.49) were also independently associated with the development of erosive esophagitis.

CONCLUSIONS

Visceral fat obesity is the key risk factor for the development of reflux erosive esophagitis in subjects aged 40-69 years.

Protective effects of Alda-1, an ALDH2 activator, on alcohol-derived DNA damage in the esophagus of human ALDH2*2 (Glu504Lys) knock-in mice

Alcohol consumption is the key risk factor for the development of esophageal squamous cell carcinoma (ESCC), and acetaldehyde, a metabolite of alcohol, is an alcohol-derived major carcinogen that causes DNA damage. Aldehyde dehydrogenase2 (ALDH2) is an enzyme that detoxifies acetaldehyde, and its activity is reduced by ALDH2 gene polymorphism. Reduction in ALDH2 activity increases blood, salivary and breath acetaldehyde levels after alcohol intake, and it is deeply associated with the development of ESCC. Heavy alcohol consumption in individuals with ALDH2 gene polymorphism significantly elevates the risk of ESCC; however, effective prevention has not been established yet. In this study, we investigated the protective effects of Alda-1, a small molecule ALDH2 activator, on alcohol-mediated esophageal DNA damage. Here, we generated novel genetically engineered knock-in mice that express the human ALDH2*1 (wild-type allele) or ALDH2*2 gene (mutant allele). Those mice were crossed, and human ALDH2*1/*1, ALDH2*1/*2 and ALDH2*2/*2 knock-in mice were established. They were given 10% ethanol for 7 days in the presence or absence of Alda-1, and we measured the levels of esophageal DNA damage, represented by DNA adduct (N²-ethylidene-2′-deoxyguanosine). Alda-1 significantly increased hepatic ALDH2 activity both in human ALDH2*1/*2 and/or ALDH2*2/*2 knock-in mice and reduced esophageal DNA damage levels after alcohol drinking. Conversely, cyanamide, an ALDH2-inhibitor, significantly exacerbated esophageal DNA adduct level in C57BL/6N mice induced by alcohol drinking. These results indicate the protective effects of ALDH2 activation by Alda-1 on esophageal DNA damage levels in individuals with ALDH2 gene polymorphism, providing a new insight into acetaldehyde-mediated esophageal carcinogenesis and prevention.

Abstract 1670: Characterization of the chick chorioallantoic membrane tumor model in comparison with various xenograft mouse tumors

Background: The chick chorioallantoic membrane (CAM) tumor model is an in vivo three-dimensional culture model that is easy to use and inexpensive, has no ethical issues, and has been used in cancer research, although the success rate of generating CAM tumors varies among reports. We analyzed the success rate of CAM tumors from patient-derived xenograft (PDX) of esophageal squamous cell carcinoma (ESCC) and many cell line-derived xenograft (CDX) tumors of different cancer types, and we sought to determine which factors affected the success rate of generating CAM tumors.

Method: We used patient cancer tissue (ESCC) and/or commercially available 12 tumorigenic cancer cell lines (esophageal cancer [TE-11 and HCE4], pancreatic cancer [CFPA-1, MIA PaCa2, and PANC-1], lung cancer [A549 and H358], skin cancer [A431 and B16F10], and biliary tract cancer [HuCCT-1, TFK-1, and MzchA2]) to generate xenograft tumors. Small (1- to 2-mm) pieces of xenograft tumors were grafted onto the CAMs of fertilized eggs. After incubating for an additional 7 to 9 days at 37.5°C and 65% humidity, nodules were observed on the assigned locations of each CAM. On the basis of hematoxylin and eosin (H&E) staining, we calculated the success rate of the CAM tumor engraftment. H&E staining was also performed with parental PDX or CDX tumors as well as parental ESCC tissues, to compare them with CAM tumors.

Results: A total of 29 xenograft tumors were transplanted onto CAMs. The overall success rate in generating CAM tumors was 19/29 (66%). The CAM tumors were histologically quite similar to those of their parental CDX or PDX tumors, and the CAM tumors from PDX ESCC were also histologically similar to their parent ESCC tumors. Tumor pieces from poorly-differentiated xenograft tumors (including PDX ESCC) generated CAM tumors with a 90% success rate (19/21), in comparison with well-differentiated xenograft tumors, whose success rate was 0% (0/8).

Conclusion: The overall success rate in generating CAM tumors, especially from poorly differentiated tumors, seems acceptable. The histological similarity between CAM tumors and both parent xenograft and parent tumors from humans indicates that the CAM tumor model is a promising in vivo model for the study of poorly differentiated tumors. As for well-differentiated tumors, this model has to be further optimized to increase the success rate of engraftment.

Citation Format: Tomoki Saito, Shinya Ohashi, Ayaka Mizumoto, Osamu Kikuchi, Kotaro Matsumoto, Aoi Komatsu, Seiji Naganuma, Yoshihiro Yamamoto, Kenshiro Hirohashi, Masahiro Yoshioka, Masashi Tamaoki, Makiko Funakoshi, Fuyuhiko Tamanoi, Manabu Muto. Characterization of the chick chorioallantoic membrane tumor model in comparison with various xenograft mouse tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1670.

Abstract PR03: An integrative mouse model of gastric premalignancy that combines early genomic alterations with disease-relevant carcinogenic exposure

Carcinogenesis from dietary byproducts and inflammation is the strongest risk factor for gastric cancer, which carries a poor prognosis owing to its advanced stage at the time of diagnosis. We therefore have a critical need to characterize key molecular mechanisms of carcinogenesis at the earliest conception of this ominous disease. To this end, we designed an integrative mouse model that combines two essential contributors to the premalignant state: (1) disease-relevant carcinogenic exposure and (2) an early genomic alteration. We recently discovered that, contrary to the previously accepted paradigm, TP53 is mutated early in malignant progression, often occurring before dysplasia. Based on these findings, we adapted a transgenic mouse to conditionally delete Trp53 in the Lgr5+ stem cell compartment of the stomach, and then exposed these mice to drinking water containing the bile acid deoxycholate (DCA), a principal component of gastroduodenal reflux, and nitroso-compound MNU, a disease-relevant carcinogen. Deletion of Trp53 in gastric stem cells of untreated mice did not lead to detectable premalignant lesions. By contrast, inactivation of Trp53in Lgr5+ stem cells of DCA/MNU-treated mice led to a 3.5-fold increase in premalignant lesions compared to wild-type control mice after one year. Whole-exome sequencing of gastric lesions showed a mutational signature associated with MNU exposure, validating that carcinogenesis contributed to the emergence of premalignant gastric lesions. Three-dimensional organoid culture recapitulates epithelial cell orientation, differentiation, and behavior in vitro. To characterize and functionally study the epithelial compartment of premalignant lesions, gastric organoids were generated from the integrative mouse model, capturing critical intermediate states in the evolution of gastric premalignancy such as genome doubling. Unbiased gene expression analyses revealed that inactivation of Trp53 in gastric premalignancy leads to activation of interferon, WNT/stemness, and cell cycle checkpoint pathways. CDKN2A was the most notable cell cycle regulator induced by Trp53 loss, which prevented progression of disease and ultimately endowed a selective pressure for inactivation in route to cancer. Indeed, genomic analysis of patient data revealed that CDKN2A and TP53 are significantly coaltered in human gastric cancer. These data demonstrate that integrating early genomic events with disease-relevant carcinogenic exposure can generate a more faithful mouse model of the premalignant state than could be achieved by either method alone. By defining the precise molecular mediators that collaborate with carcinogenesis to endorse premalignant gastric lesions, we hope to inform the design of effective prevention strategies tailored to definitively treat patients before a window of opportunity has closed.

This abstract is also being presented as Poster A37.

Citation Format: Nilay Sethi, Osamu Kikuchi, Gina Duronio, Matthew Stachler, James McFarland, Adam J. Bass. An integrative mouse model of gastric premalignancy that combines early genomic alterations with disease-relevant carcinogenic exposure [abstract]. In: Proceedings of the AACR Special Conference on Environmental Carcinogenesis: Potential Pathway to Cancer Prevention; 2019 Jun 22-24; Charlotte, NC. Philadelphia (PA): AACR; Can Prev Res 2020;13(7 Suppl): Abstract nr PR03.

Synthetic Lethality with Trifluridine/Tipiracil and Checkpoint Kinase 1 Inhibitor for Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is a disease characterized by a high mutation rate of the TP53 gene, which plays pivotal roles in the DNA damage response (DDR) and is regulated by checkpoint kinase (CHK) 2. CHK1 is another key DDR-related protein, and its selective inhibition is suggested to be particularly sensitive to TP53-mutated cancers, because a loss of both pathways (CHK1 and/or CHK2-p53) is lethal due to the serious impairment of DDR. Such a therapeutic strategy is termed synthetic lethality. Here, we propose a novel therapeutic strategy based on synthetic lethality combining trifluridine/tipiracil and prexasertib (CHK1 inhibitor) as a treatment for ESCC. Trifluridine is a key component of the antitumor drug combination with trifluridine/tipiracil (an inhibitor of trifluridine degradation), also known as TAS-102. In this study, we demonstrate that trifluridine increases CHK1 phosphorylation in ESCC cells combined with a reduction of the S-phase ratio as well as the induction of ssDNA damage. Because CHK1 phosphorylation is considered to be induced as DDR for trifluridine-mediated DNA damage, we examined the effects of CHK1 inhibition on trifluridine treatment. Consequently, CHK1 inhibition by short hairpin RNA or treatment with the CHK1 inhibitor, prexasertib, markedly enhanced trifluridine-mediated DNA damage, represented by an increase of γH2AX expression. Moreover, the combination of trifluridine/tipiracil and CHK1 inhibition significantly suppressed tumor growth of ESCC-derived xenograft tumors. Furthermore, the combination of trifluridine and prexasertib enhanced radiosensitivity both in vitro and in vivo Thus, the combination of trifluridine/tipiracil and a CHK1 inhibitor exhibits effective antitumor effects, suggesting a novel therapeutic strategy for ESCC.

Experimental model for the irradiation-mediated abscopal effect and factors influencing this effect

Radiotherapy (RT) is the primary treatment for cancer. Ionizing radiation from RT induces tumor damage at the irradiated site, and, although clinically infrequent, may cause regression of tumors distant from the irradiated site-a phenomenon known as the abscopal effect. Recently, the abscopal effect has been related to prolongation of overall survival time in cancer patients, though the factors that influence the abscopal effect are not well understood. The aim of this study is to clarify the factors influencing on abscopal effect. Here, we established a mouse model in which we induced the abscopal effect. We injected MC38 (mouse colon adenocarcinoma) cells subcutaneously into C57BL/6 mice at two sites. Only one tumor was irradiated and the sizes of both tumors were measured over time. The non-irradiated-site tumor showed regression, demonstrating the abscopal effect. This effect was enhanced by an increase in the irradiated-tumor volume and by administration of anti-PD1 antibody. When the abscopal effect was induced by a combination of RT and anti-PD1 antibody, it was also influenced by radiation dose and irradiated-tumor volume. These phenomena were also verified in other cell line, B16F10 cells (mouse melanoma cells). These findings provide further evidence of the mechanism for, and factors that influence, the abscopal effect in RT.

Genomics and Targeted Therapies in Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinomas (GEA) are devastating diseases with stark global presence. Over the past 10 years, there have been minimal improvements in treatment approach despite numerous clinical trials. Here, we review recent progress toward understanding the molecular features of these cancers and the diagnostic and therapeutic challenges posed by their intrinsic genomic instability and heterogeneity. We highlight the potential of genomic heterogeneity to influence clinical trial outcomes for targeted therapies and emphasize the need for comprehensive molecular profiling to guide treatment selection and adapt treatment to resistance and genomic evolution. Revising our clinical approach to GEA by leveraging genomic advances will be integral to the success of current and future treatments, especially as novel targets become therapeutically tractable. SIGNIFICANCE: GEAs are deadly cancers with few treatment options. Characterization of the genomic landscape of these cancers has revealed considerable genetic diversity and spatial heterogeneity. Understanding these fundamental properties of GEA will be critical for overcoming barriers to the development of novel, more effective therapeutic strategies.

Mutant p53 induces a hypoxia transcriptional program in gastric and esophageal adenocarcinoma

Despite the propensity for gastric and esophageal adenocarcinomas to select for recurrent missense mutations in TP53, the precise functional consequence of these mutations remains unclear. Here we report that endogenous mRNA and protein levels of mutant p53 were elevated in cell lines and patients with gastric and esophageal cancer. Functional studies showed that mutant p53 was sufficient, but not necessary, for enhancing primary tumor growth in vivo. Unbiased genome-wide transcriptome analysis revealed that hypoxia signaling was induced by mutant p53 in 2 gastric cancer cell lines. Using real-time in vivo imaging, we confirmed that hypoxia reporter activity was elevated during the initiation of mutant p53 gastric cancer xenografts. Unlike HIF co-factor ARNT, HIF1α was required for primary tumor growth in mutant p53 gastric cancer. These findings elucidate the contribution of missense p53 mutations in gastroesophageal malignancy and indicate that hypoxia signaling rather than mutant p53 itself may serve as a therapeutic vulnerability in these deadly set of cancers.

Combination treatment with highly bioavailable curcumin and NQO1 inhibitor exhibits potent antitumor effects on esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most intractable cancers, so the development of novel therapeutics has been required to improve patient outcomes. Curcumin, a polyphenol from Curcuma longa, exhibits various health benefits including antitumor effects, but its clinical utility is limited because of low bioavailability. Theracurmin^® (THC) is a highly bioavailable curcumin dispersed with colloidal submicron particles.

METHODS

We examined antitumor effects of THC on ESCC cells by cell viability assay, colony and spheroid formation assay, and xenograft models. To reveal its mechanisms, we investigated the levels of reactive oxygen species (ROS) and performed microarray gene expression analysis. According to those analyses, we focused on NQO1, which involved in the removal of ROS, and examined the effects of NQO1-knockdown or overexpression on THC treatment. Moreover, the therapeutic effect of THC and NQO1 inhibitor on ESCC patient-derived xenografts (PDX) was investigated.

RESULTS

THC caused cytotoxicity in ESCC cells, and suppressed the growth of xenografted tumors more efficiently than curcumin. THC increased ROS levels and activated the NRF2-NMRAL2P-NQO1 expressions. Inhibition of NQO1 in ESCC cells by shRNA or NQO1 inhibitor resulted in an increased sensitivity of cells to THC, whereas overexpression of NQO1 antagonized it. Notably, NQO1 inhibitor significantly enhanced the antitumor effects of THC in ESCC PDX tumors.

CONCLUSIONS

These findings suggest the potential usefulness of THC and its combination with NQO1 inhibitor as a therapeutic option for ESCC.

Neuronal SIRT1 regulates macronutrient-based diet selection through FGF21 and oxytocin signalling in mice

Diet affects health through ingested calories and macronutrients, and macronutrient balance affects health span. The mechanisms regulating macronutrient-based diet choices are poorly understood. Previous studies had shown that NAD-dependent deacetylase sirtuin-1 (SIRT1) in part influences the health-promoting effects of caloric restriction by boosting fat use in peripheral tissues. Here, we show that neuronal SIRT1 shifts diet choice from sucrose to fat in mice, matching the peripheral metabolic shift. SIRT1-mediated suppression of simple sugar preference requires oxytocin signalling, and SIRT1 in oxytocin neurons drives this effect. The hepatokine FGF21 acts as an endocrine signal to oxytocin neurons, promoting neuronal activation and Oxt transcription and suppressing the simple sugar preference. SIRT1 promotes FGF21 signalling in oxytocin neurons and stimulates Oxt transcription through NRF2. Thus, neuronal SIRT1 contributes to the homeostatic regulation of macronutrient-based diet selection in mice.

Three-Dimensional Organoids Reveal Therapy Resistance of Esophageal and Oropharyngeal Squamous Cell Carcinoma Cells

BACKGROUND & AIMS

Oropharyngeal and esophageal squamous cell carcinomas, especially the latter, are a lethal disease, featuring intratumoral cancer cell heterogeneity and therapy resistance. To facilitate cancer therapy in personalized medicine, three-dimensional (3D) organoids may be useful for functional characterization of cancer cells ex vivo. We investigated the feasibility and the utility of patient-derived 3D organoids of esophageal and oropharyngeal squamous cell carcinomas.

METHODS

We generated 3D organoids from paired biopsies representing tumors and adjacent normal mucosa from therapy-naïve patients and cell lines. We evaluated growth and structures of 3D organoids treated with 5-fluorouracil ex vivo.

RESULTS

Tumor-derived 3D organoids were grown successfully from 15 out of 21 patients (71.4%) and passaged with recapitulation of the histopathology of the original tumors. Successful formation of tumor-derived 3D organoids was associated significantly with poor response to presurgical neoadjuvant chemotherapy or chemoradiation therapy in informative patients (P = 0.0357, progressive and stable diseases, n = 10 vs. partial response, n = 6). The 3D organoid formation capability and 5-fluorouracil resistance were accounted for by cancer cells with high CD44 expression and autophagy, respectively. Such cancer cells were found to be enriched in patient-derived 3D organoids surviving 5-fluorouracil treatment.

CONCLUSIONS

The single cell-based 3D organoid system may serve as a highly efficient platform to explore cancer therapeutics and therapy resistance mechanisms in conjunction with morphological and functional assays with implications for translation in personalized medicine.

Early diagnosis of pancreatic necrosis based on perfusion CT to predict the severity of acute pancreatitis

BACKGROUND

Perfusion CT can diagnose pancreatic necrosis in early stage of severe acute pancreatitis, accurately. However, no study to date has examined whether early diagnosis of pancreatic necrosis is useful in predicting persistent organ failure (POF).

METHODS

We performed a multi-center prospective observational cohort study to investigate whether perfusion CT can predict the development of POF in the early stage of AP, based on early diagnosis of the development of pancreatic necrosis (PN). From 2009 to 2012, we examined patients showing potential early signs of severe AP (n = 78) on admission. Diagnoses for the development of PN were made prospectively by on-site physicians on the admission based on perfusion CT (diagnosis 1). Blinded retrospective reviews were performed by radiologists A and B, having 8 and 13 years of experience as radiologists (diagnosis 2 and 3), respectively. Positive diagnosis for the development of PN were assumed equivalent to positive predictions for the development of POF. We then calculated the area under the curve (AUC) of the receiver operating characteristic for POF predictions.

RESULTS

Fourteen (17.9%) and 23 patients (29.5%) developed PN and POF, respectively. For diagnoses 1, 2, and 3, AUCs for POF predictions were 74, 68, and 73, respectively.

CONCLUSIONS

Perfusion CT diagnoses pancreatic necrosis and on that basis predicts the development of POF; http://www.umin.ac.jp/ctr/index-j.htm,UMIN000001926 .

Novel EGFR-targeted strategy with hybrid peptide against oesophageal squamous cell carcinoma

Epidermal growth factor receptor (EGFR) is a key molecule in the pathophysiology of oesophageal squamous cell carcinoma (OSCC). However, EGFR-targeted agents such as anti-EGFR antibody or tyrosine kinase inhibitors for OSCC have not demonstrated any clinical benefits. Recently, a novel chemotherapeutic agent, EGFR(2R)-lytic hybrid peptide, a composite of EGFR-binding peptide and lytic peptide fragments, has been shown to exhibit a potent anti-tumour effect against cancers that express high EGFR levels. In this study, we investigated the validity of employing EGFR(2R)-lytic hybrid peptide against OSCC cells both in vitro and in vivo. Additionally, the toxicity of this peptide was assessed in mice. We found high EGFR expression levels on the cell surface of OSCC cells, and the EGFR-binding peptide fragment showed high affinity for OSCC cells. A potent cytotoxic effect was induced within 30 minutes by the exposure of OSCC cells to EGFR(2R)-lytic hybrid peptide. Furthermore, EGFR(2R)-lytic hybrid peptide markedly suppressed the tumour growth of OSCC cells in a xenograft model. Moreover, it did not cause any identifiable adverse effects in mice. Taken together, EGFR(2R)-lytic hybrid peptide was shown to be a valid therapeutic agent against OSCC, providing a crucial rationale regarding novel EGFR-targeted therapies against OSCC.

Abstract B31: Establishment of a 5-fluorouracil-resistant esophageal squamous cell carcinoma cells with dihydropyrimidine dehydrogenase gene amplification

5-Fluorouracil (5-FU) is the key drug for the treatment of esophageal squamous cell carcinoma (ESCC), however, resistance to 5-FU remains a critical limitation to the clinical use. To clarify the mechanisms of 5-FU resistance in ESCC, we have established a 5-FU-resistant ESCC cell line TE-5R from parental TE-5 cells, by treatment with the step-wise continuous increasing concentrations of 5-FU. The half maximal inhibitory concentration of 5-FU showed that TE-5R cells were 15.6-fold resistant to 5-FU in comparison with TE-5 cells. Intracellular 5-FU concentration was significantly lower in TE-5R cells than in TE-5 cells. TE-5R cells showed regional copy number amplification of chromosome 1p including the DPYD gene, as well as high mRNA and protein expressions of dihydropyrimidine dehydrogenase (DPD), an enzyme involved in 5-FU degradation, whereas copy number of the other 5-FU metabolism-related genes in TE-5R cells did not changed from TE-5 cells. Gimeracil, a DPD inhibitor, sharply restored 5-FU resistance and increased intracellular 5-FU concentration in TE-5R cells. Next, to investigate whether other 5-FU metabolism-related genes contributed to 5-FU resistance in TE-5R cells, we added microarray gene expression assay and no significant differences in the expression of 5-FU metabolism-related genes were detected. These results indicate that 5-FU resistance in TE-5R cells is based on a DPD-dependent rapid degradation of 5-FU. Taken together, we established novel 5-FU-resistant TE-5R cells, which may have obtained 5-FU resistance with DPD copy number amplification and consequent overexpression, providing a critical insight to explore a new strategy against 5-FU-resistant ESCC using DPD inhibitor.

Citation Format: Osamu Kikuchi, Kiichiro Baba, Shinya Ohashi, Manabu Muto. Establishment of a 5-fluorouracil-resistant esophageal squamous cell carcinoma cells with dihydropyrimidine dehydrogenase gene amplification. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr B31.

Recent Advances From Basic and Clinical Studies of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive squamous cell carcinomas and is highly prevalent in Asia. Alcohol and its metabolite, acetaldehyde, are considered definite carcinogens for the esophagus. Polymorphisms in the aldehyde dehydrogenase 2 gene, which encodes an enzyme that eliminates acetaldehyde, have been associated with esophageal carcinogenesis. Studies of the mutagenic and carcinogenic effects of acetaldehyde support this observation. Several recent large-scale comprehensive analyses of the genomic alterations in ESCC have shown a high frequency of mutations in genes such as TP53 and others that regulate the cell cycle or cell differentiation. Moreover, whole genome and whole exome sequencing studies have frequently detected somatic mutations, such as G:C→A:T transitions or G:C→C:G transversions, in ESCC tissues. Genomic instability, caused by abnormalities in the Fanconi anemia DNA repair pathway, is also considered a pathogenic mechanism of ESCC. Advances in diagnostic techniques such as magnifying endoscopy with narrow band imaging or positron emission tomography have increased the accuracy of diagnosis of ESCC. Updated guidelines from the National Comprehensive Cancer Network standardize the practice for the diagnosis and treatment of esophageal cancer. Patients with ESCC are treated endoscopically or with surgery, chemotherapy, or radiotherapy, based on tumor stage. Minimally invasive treatments help improve the quality of life of patients who undergo such treatments. We review recent developments in the diagnosis and treatment of ESCC and advances gained from basic and clinical research.

Abstract 5346: Notch3-mediated squamous cell differentiation shows anti-tumor effect on esophageal squamous cell carcinoma as well as reduces its resistance to 5-Fluorouracil

BACKGROUND: We have shown that Notch3 plays an important role in the regulation of esophageal squamous cell differentiation. However, it remains unclear how Notch3-mediated squamous cell differentiation influences the tumorigenicity of esophageal squamous cell carcinoma (ESCC) or its sensitivity to anti-cancer agents, including 5-Fluorouracil (5-FU).

METHODS: We used 5-FU-resistant human ESCC cells, TE-11R, established by the step-wise continuous exposure of parental TE-11 cells to 5-FU. The TE-11R cells were stably transduced with intracellular domain of Notch3 (ICN3), an active form of Notch3, in a regulatable manner (Tet-On system). The anti-tumor effect of Notch3-overexpression was evaluated by implanting those cells into NOD SCID mice. 5-FU resistance was determined by calculating the 50% inhibitory concentration (IC50) of 5-FU using the WST-1 assay. Gene expression of squamous differentiation markers such as involucrin and cytokeratin 13 (CK13) as well as proliferative activity were determined.

RESULTS: TE-11R cells formed bulky tumors in NOD SCID mice, and the tumor formation rate of TE-11R cells (6/6: 100%) was higher than that of TE-11 cells (1/8: 12.5%). TE-11R-derived tumors showed a less differentiated and more proliferative phenotype represented by fewer ‘keratin pearl’ formations with lower involucrin and Notch3 expressions as well as higher Ki67 expression in comparison with TE-11-derived tumors. Consistent with this, TE-11R cells showed lower gene expressions of Notch3, involucrin, and CK13, and exhibited approximately 1.4-fold higher proliferative activity than parental TE-11 cells in vitro. Notch3 overexpression resulted in the promotion of cell differentiation accompanied by increased expressions of involucrin and CK13, and suppressed cell growth in vitro as well as tumorigenicity in vivo. Finally, it clearly reduced the 5-FU resistance of TE-11R cells in vitro. IC50 values of TE-11R-ICN3 (DOX-) and TE-11R-ICN3 (DOX+) were 96.0 ± 19.7 and 21.6 ± 10.4 μM (P < 0.01), respectively.

CONCLUSION: Our study showed that Notch3-mediated squamous cell differentiation reduced both the tumorigenicity and 5-FU resistance of ESCC cells. We suggest that a strategy to promote squamous cell differentiation may ameliorate the outcome associated with 5-FU-resistant ESCC.

Citation Format: Osamu Kikuchi, Shinya Ohashi, Yukie Nakai, Yusuke Amanuma, Masahiro Yoshioka, Shin'ichi Miyamoto, Mitsuteru Natsuizaka, Hiroshi Nakagawa, Tsutomu Chiba, Manabu Muto. Notch3-mediated squamous cell differentiation shows anti-tumor effect on esophageal squamous cell carcinoma as well as reduces its resistance to 5-Fluorouracil. [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 5346. doi:10.1158/1538-7445.AM2015-5346

Novel 5-fluorouracil-resistant human esophageal squamous cell carcinoma cells with dihydropyrimidine dehydrogenase overexpression

5-Fluorouracil (5-FU) is a key drug for the treatment of esophageal squamous cell carcinoma (ESCC); however, resistance to it remains a critical limitation to its clinical use. To clarify the mechanisms of 5-FU resistance of ESCC, we originally established 5-FU-resistant ESCC cells, TE-5R, by step-wise treatment with continuously increasing concentrations of 5-FU. The half maximal inhibitory concentration of 5-FU showed that TE-5R cells were 15.6-fold more resistant to 5-FU in comparison with parental TE-5 cells. TE-5R cells showed regional copy number amplification of chromosome 1p including the DPYD gene, as well as high mRNA and protein expressions of dihydropyrimidine dehydrogenase (DPD), an enzyme involved in 5-FU degradation. 5-FU treatment resulted in a significant decrease of the intracellular 5-FU concentration and increase of the concentration of α-fluoro-ureidopropionic acid (FUPA), a metabolite of 5-FU, in TE-5R compared with TE-5 cells in vitro. Conversely, gimeracil, a DPD inhibitor, markedly increased the intracellular 5-FU concentration, decreased the intracellular FUPA concentration, and attenuated 5-FU resistance of TE-5R cells. These results indicate that 5-FU resistance of TE-5R cells is due to the rapid degradation of 5-FU by DPD overexpression. The investigation of 5-FU-resistant ESCC with DPYD gene copy number amplification and consequent DPD overexpression may generate novel biological evidence to explore strategies against ESCC with 5-FU resistance.

Serum miR-21, miR-29a, and miR-125b Are Promising Biomarkers for the Early Detection of Colorectal Neoplasia

PURPOSE

Circulating microRNAs (miRNA) are emerging as promising diagnostic biomarkers for colorectal cancer, but their usefulness for detecting early colorectal neoplasms remains unclear. This study aimed to identify serum miRNA biomarkers for the identification of patients with early colorectal neoplasms.

EXPERIMENTAL DESIGN

A cohort of 237 serum samples from 160 patients with early colorectal neoplasms (148 precancerous lesions and 12 cancers) and 77 healthy subjects was analyzed in a three-step approach that included a comprehensive literature review for published biomarkers, a screening phase, and a validation phase. RNA was extracted from sera, and levels of miRNAs were examined by real-time RT-PCR.

RESULTS

Nine miRNAs (miR-18a, miR-19a, miR-19b, miR-20a, miR-21, miR-24, miR-29a, miR-92, and miR-125b) were selected as candidate biomarkers for initial analysis. In the screening phase, serum levels of miR-21, miR-29a, and miR-125b were significantly higher in patients with early colorectal neoplasm than in healthy controls. Elevated levels of miR-21, miR-29a, and miR-125b were confirmed in the validation phase using an independent set of subjects. Area under the curve (AUC) values for serum miR-21, miR-29a, miR-125b, and their combined score in discriminating patients with early colorectal neoplasm from healthy controls were 0.706, 0.741, 0.806, and 0.827, respectively. Serum levels of miR-29a and miR-125b were significantly higher in patients who had only small colorectal neoplasms (≤5 mm) than in healthy subjects.

CONCLUSIONS

Because serum levels of miR-21, miR-29a, and miR-125b discriminated patients with early colorectal neoplasm from healthy controls, our data highlight the potential clinical use of these molecular signatures for noninvasive screening of patients with colorectal neoplasia.

Overexpression of insulin receptor partially improves obese and diabetic phenotypes in db/db mice

Type 2 diabetes mellitus (T2DM) is one of the major health concern among the world. Several treatment options for T2DM are in clinical use, including injecting insulin, promoting insulin secretion by insulin secretagogues, and improving insulin sensitivity by insulin sensitizers. However, increasing the amount of insulin receptor in insulin-target tissues has not been explored. In order to test the efficacy of insulin receptor overexpression for improving glucose control, we established a transgenic mouse line expressing human insulin receptor (INSR). We analyzed, growth, energy balance, and glucose control of INSR-overexpressing db/db mice (INSR; db/db), which we produced by mating INSR transgenic mice with db/db mice, a genetic model of obesity due to insufficient leptin signaling. Compared to db/db mice, INSR; db/db mice were rescued from hyperphagia and obesity, leading to improved blood glucose levels. Unexpectedly, however, INSR; db/db mice presented with stunted growth, accompanied by decreased plasma levels of free IGF1 and IGFBP-3, indicating the down-regulation of GH/IGF1 axis. These phenotypes were observed in INSR; db/db mice but not in INSR littermates. Meanwhile, bone defects observed in db/db male mice were not rescued. Moreover, improved blood glucose was not accompanied by improved insulin sensitivity. Therefore, overexpression of insulin receptor improves obese and diabetic phenotypes in db/db mice, with consequences on growth.

Abstract 867: Serum microRNAs as diagnostic biomarkers for early colorectal neoplasms

Objectives: Early detection of precancerous lesions and early-stage cancers are essential to reduce mortality from colorectal cancer (CRC).

Serum/plasma microRNAs (miRs) have been reported as diagnostic and prognostic biomarkers of CRC, but their utility in detecting patients with early lesions has not been fully explored. The aim of this study is to identify serum miRs which are potentially useful as diagnostic biomarkers for early colorectal neoplasms, and potential confounders in a blood test.

Methods: Candidate biomarker miRs were selected from previously published studies. Serum samples were collected from patients with low-grade intraepithelial neoplasias (LGINs) including tubular adenomas and tubulovillous adenomas, high-grade intraepithelial neoplasias (HGINs), early cancers, and healthy volunteers, and divided into discovery and validation sets. Total RNA was extracted from serum samples and levels of candidate miRs were measured by real-time RT-PCR. To evaluate the impact of hemolysis on serum miR levels, serially diluted hemolysed controls were prepared from stock solution made by hemolysing the red blood cells in distilled water. Levels of candidate miRs in hemolysed controls were also examined by real-time RT-PCR. Absorbance of serum samples at 560 nm, 576 nm, and 592 nm was measured by spectrophotometry and hemoglobin levels were estimated from a standard curve.

Results: Fourteen miRs were selected as candidate diagnostic biomarkers of early colorectal neoplasms from a review of the literature. Serum levels of five miRs were too low to be accurately quantified by real-time RT-PCR, and excluded from further evaluation. Sera from 12 patients with LGINs, 8 patients with HGINs, 4 patients with cancers, and 25 healthy volunteers were included in the discovery phase. Of 9 miRs examined, miR21 (p = 0.0007), miR29a (p < 0.0001) and miR125b (p = 0.0198) showed significantly higher levels in sera from early colorectal neoplasms compared to those from healthy volunteers. Higher levels of miR29a and miR125b in sera from early colorectal neoplasms were confirmed in the validation phase using independent set of samples. Levels of miR21, 29a, and miR125b in sera significantly correlated with the degree of hemolysis.

Conclusions: Serum miRs may be useful biomarkers to detect patients with early colorectal neoplasia, including adenomas. Hemolysis affects serum miR levels, and will confound measurement. Since hemolysis occurs frequently during blood collection, its impact on serum miRs should be further investigated.

Citation Format: Atsushi Yamada, Takahiro Horimatsu, Yoshinaga Okugawa, Naoshi Nishida, Tadayuki Kou, Toshihiro Kusaka, Hajime Honjo, Yusuke Amanuma, Osamu Kikuchi, Manabu Muto, Ajay Goel, C. Richard Boland. Serum microRNAs as diagnostic biomarkers for early colorectal neoplasms. [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 867. doi:10.1158/1538-7445.AM2014-867

Sirt1 rescues the obesity induced by insulin-resistant constitutively-nuclear FoxO1 in POMC neurons of male mice

OBJECTIVE

The hypothalamus is the brain center that controls the energy balance. Anorexigenic proopiomelanocortin (POMC) neurons and orexigenic AgRP neurons in the arcuate nucleus of the hypothalamus plays critical roles in energy balance regulation. FoxO1 is a transcription factor regulated by insulin signaling that is deacetylated by Sirt1, a nicotinamide adenine dinucleotide- (NAD(+) -) dependent deacetylase. Overexpression of insulin-resistant constitutively-nuclear FoxO1 (CN-FoxO1) in POMC neurons leads to obesity, whereas Sirt1 overexpression in POMC neurons leads to leanness. Whether overexpression of Sirt1 in POMC neurons could rescue the obesity caused by insulin-resistant CN-FoxO1 was tested here.

METHODS

POMC neuron-specific CN-FoxO1/Sirt1 double-KI (DKI) mice were analyzed.

RESULTS

The obese phenotype of CN-FoxO1 KI mice was rescued in male DKI mice. Reduced O2 consumption, increased adiposity, and fewer POMC neurons observed in CN-FoxO1 mice were rescued in male DKI mice without affecting food intake and locomotor activity. Sirt1 overexpression decreased FoxO1 acetylation and protein levels without affecting its nuclear localization in mouse embryonic fibroblasts and hypothalamic N41 cells.

CONCLUSIONS

Sirt1 rescues the obesity induced by insulin-resistant CN-FoxO1 in POMC neurons of male mice by decreasing FoxO1 protein through deacetylation. Sirt1 ameliorates obesity caused by a genetic model of central insulin resistance.

Preclinical validation of talaporfin sodium-mediated photodynamic therapy for esophageal squamous cell carcinoma

Photodynamic therapy (PDT) kills cancer cells via a photochemical reaction mediated by an oncotropic photosensitizer. Herein, we performed an experimental preclinical study to validate the anti-tumour effect of talaporfin sodium-mediated PDT (t-PDT) for esophageal squamous cell carcinoma (ESCC) cells. We used human ESCC cells derived from various differentiation grades or resistant to 5-fluorouracil (5-FU). The cytotoxic effect of t-PDT was determined by evaluating cell viability, apoptosis and generation of reactive oxygen species (ROS) and DNA double-strand breaks. Furthermore, the anti-tumour effect of t-PDT was assessed using an anchorage-independent cell-growth assay and xenograft transplantation models. t-PDT induced potent cytotoxicity in ESCC cells independent of their differentiation grade or 5-FU resistance. Moreover, t-PDT induced robust apoptosis, as indicated by cell shrinkage, perinuclear vacuolization, nuclear fragmentation and induction of annexin V-positive cells. This apoptotic response was accompanied by concurrent activation of ROS, and induction of DNA double-strand breakage. Importantly, t-PDT suppressed efficiently anchorage-independent cell growth as well as ESCC-xenografted tumor formation. In aggregate, t-PDT showed anti-tumor potential for ESCC cells with various histological grades or chemoresistance, providing a novel translational rationale of t-PDT for the treatment of ESCC.

Impairment of aldehyde dehydrogenase 2 increases accumulation of acetaldehyde-derived DNA damage in the esophagus after ethanol ingestion

Ethanol and its metabolite, acetaldehyde, are the definite carcinogens for esophageal squamous cell carcinoma (ESCC), and reduced catalytic activity of aldehyde dehydrogenase 2 (ALDH2), which detoxifies acetaldehyde, increases the risk for ESCC. However, it remains unknown whether the ALDH2 genotype influences the level of acetaldehyde-derived DNA damage in the esophagus after ethanol ingestion. In the present study, we administered ethanol orally or intraperitoneally to Aldh2-knockout and control mice, and we quantified the level of acetaldehyde-derived DNA damage, especially N(2) -ethylidene-2'-deoxyguanosine (N(2) -ethylidene-dG), in the esophagus. In the model of oral ethanol administration, the esophageal N(2) -ethylidene-dG level was significantly higher in Aldh2-knockout mice compared with control mice. Similarly, in the model of intraperitoneal ethanol administration, in which the esophagus is not exposed directly to the alcohol solution, the esophageal N(2) -ethylidene-dG level was also elevated in Aldh2-knockout mice. This result indicates that circulating ethanol-derived acetaldehyde causes esophageal DNA damage, and that the extent of damage is influenced by knockout of Aldh2. Taken together, our findings strongly suggest the importance of acetaldehyde-derived DNA damage which is induced in the esophagus of individuals with ALDH2 gene impairment. This provides a physiological basis for understanding alcohol-related esophageal carcinogenesis.

Hypothalamic SIRT1 prevents age-associated weight gain by improving leptin sensitivity in mice

AIMS/HYPOTHESIS

Obesity is associated with ageing and increased energy intake, while restriction of energy intake improves health and longevity in multiple organisms; the NAD(+)-dependent deacetylase sirtuin 1 (SIRT1) is implicated in this process. Pro-opiomelanocortin (POMC) and agouti-related peptide (AgRP) neurons in the arcuate nucleus (ARC) of the hypothalamus are critical for energy balance regulation, and the level of SIRT1 protein decreases with age in the ARC. In the current study we tested whether conditional Sirt1 overexpression in mouse POMC or AgRP neurons prevents age-associated weight gain and diet-induced obesity.

METHODS

We targeted Sirt1 cDNA sequence into the Rosa26 locus and generated conditional Sirt1 knock-in mice. These mice were crossed with mice harbouring either Pomc-Cre or Agrp-Cre and the metabolic variables, food intake, energy expenditure and sympathetic activity in adipose tissue of the resultant mice were analysed. We also used a hypothalamic cell line to investigate the molecular mechanism by which Sirt1 overexpression modulates leptin signalling.

RESULTS

Conditional Sirt1 overexpression in mouse POMC or AgRP neurons prevented age-associated weight gain; overexpression in POMC neurons stimulated energy expenditure via increased sympathetic activity in adipose tissue, whereas overexpression in AgRP neurons suppressed food intake. SIRT1 improved leptin sensitivity in hypothalamic neurons in vitro and in vivo by downregulating protein-tyrosine phosphatase 1B, T cell protein-tyrosine phosphatase and suppressor of cytokine signalling 3. However, these phenotypes were absent in mice consuming a high-fat, high-sucrose diet due to decreases in ARC SIRT1 protein and hypothalamic NAD(+) levels.

CONCLUSIONS/INTERPRETATION

ARC SIRT1 is a negative regulator of energy balance, and decline in ARC SIRT1 function contributes to disruption of energy homeostasis by ageing and diet-induced obesity.

ATF3 expression is induced by low glucose in pancreatic α and β cells and regulates glucagon but not insulin gene transcription

The pancreas is critical for maintaining glucose homeostasis. Activating transcription factor 3 (ATF3) is an adaptive response transcription factor. There are major discrepancies in previous reports on pancreatic ATF3; therefore, its role in the pancreas is unclear. To better elucidate the role of ATF3 in the pancreas, we conducted in vitro studies using pancreatic α and β cell lines, and also evaluated the use of ATF3 antibodies for immunohistochemistry. We determined ATF3 expression was increased by low glucose and decreased by high glucose in both αTC-1.6 and βTC3 cells. We also showed that adenovirus-mediated ATF3 overexpression increased glucagon promoter activity and glucagon mRNA levels in αTC-1.6 cells; whereas, it had no effect on insulin promoter activity and insulin mRNA levels in βTC3 cells. Although immunostaining with the C-19 ATF3 antibody demonstrated predominant expression in α cells rather than β cells, ATF3 staining was still detected in ATF3 knockout mice as clearly as in control mice. On the other hand, another ATF3 antibody (H-90) detected ATF3 in both α cells and β cells, and was clearly diminished in ATF3 knockout mice. These results indicate that previous discrepancies in ATF3 expression patterns in the pancreas were caused by the varying specificities of the ATF3 antibodies used, and that ATF3 is actually expressed in both α cells and β cells.

Hypothalamic ATF3 is involved in regulating glucose and energy metabolism in mice

AIMS/HYPOTHESIS

The pancreas and hypothalamus are critical for maintaining nutrient and energy homeostasis, and combined disorders in these organs account for the onset of the metabolic syndrome. Activating transcription factor 3 (ATF3) is an adaptive response transcription factor. The physiological role of ATF3 in the pancreas has been controversial, and its role in the hypothalamus remains unknown. To elucidate the roles of ATF3 in these organs, we generated pancreas- and hypothalamus-specific Atf3 knockout (PHT-Atf3-KO) mice in this study.

METHODS

We crossed mice bearing floxed Atf3 alleles with Pdx1-cre mice, in which cre is specifically expressed in the pancreas and hypothalamus, and analysed metabolic variables, pancreatic morphology, food intake, energy expenditure and sympathetic activity in adipose tissue. We also used a hypothalamic cell line to investigate the molecular mechanism by which ATF3 regulates transcription of the gene encoding agouti-related protein (Agrp).

RESULTS

Although PHT-Atf3-KO mice displayed better glucose tolerance, neither plasma glucagon nor insulin level was altered in these mice. However, these mice exhibited higher insulin sensitivity, which was accompanied by a leaner phenotype due to decreased food intake and increased energy expenditure. We also observed decreased hypothalamic Agrp expression in PHT-Atf3-KO mice. Importantly, an increase in ATF3 levels is induced by fasting or low glucose in the hypothalamus. We also showed that ATF3 interacts with forkhead box-containing protein, O subfamily 1 (FoxO1) on the Agrp promoter and activates Agrp transcription.

CONCLUSIONS/INTERPRETATION

Our results suggest that ATF3 plays an important role in the control of glucose and energy metabolism by regulating Agrp.

Miglitol prevents diet-induced obesity by stimulating brown adipose tissue and energy expenditure independent of preventing the digestion of carbohydrates

Miglitol is an alpha-glucosidase inhibitor that improves post-prandial hyperglycemia, and it is the only drug in its class that enters the bloodstream. Anecdotally, miglitol lowers patient body weight more effectively than other alpha-glucosidase inhibitors, but the precise mechanism has not been addressed. Therefore, we analyzed the anti-obesity effects of miglitol in mice and in the HB2 brown adipocyte cell line. Miglitol prevented diet-induced obesity by stimulating energy expenditure without affecting food intake in mice. Long-term miglitol treatment dose-dependently prevented diet-induced obesity and induced mitochondrial gene expression in brown adipose tissue. The anti-obesity effect was independent of preventing carbohydrate digestion in the gastrointestinal tract. Miglitol effectively stimulated energy expenditure in mice fed a high-fat high-monocarbohydrate diet, and intraperitoneal injection of miglitol was sufficient to stimulate energy expenditure in mice. Acarbose, which is a non-absorbable alpha glucosidase inhibitor, also prevented diet-induced obesity, but through a different mechanism: it did not stimulate energy expenditure, but caused indigestion, leading to less energy absorption. Miglitol promoted adrenergic signaling in brown adipocytes in vitro. These data indicate that circulating miglitol stimulates brown adipose tissue and increases energy expenditure, thereby preventing diet-induced obesity. Further optimizing miglitol's effect on brown adipose tissue could lead to a novel anti-obesity drug.

Endoscopic Submucosal Dissection for Treatment of Patients Aged 75 Years and over with Esophageal Cancer

Background. Although many reports concerning the use of endoscopic submucosal dissection (ESD) for esophageal cancer have been published, the feasibility of ESD in elderly patients has not been reported. Therefore, we evaluated the efficacy and safety of ESD for treating early esophageal cancer in elderly patients. Methods. A total of 62 cases (52 men, 10 women; mean age ± standard deviation, 66.5 ± 10.5 years) for which the first resection (first treatment) of esophageal cancer was performed by ESD were identified from 77 consecutive esophageal epithelial cancers in 67 patients treated at our institution from January 2005 to March 2011. Patient characteristics, clinical findings, and outcomes were retrospectively assessed for patients separated into older (aged 75 years and older) and younger (aged under 75 years) groups. Results. No significant differences in specimen size, procedure time, median length of the hospital stay (8 versus 9 days; P = 0.252) or procedure-associated complications (8% versus 27%; P = 0.264) were observed between the older (n = 13) and younger (n = 49) groups. Lesions were completely resected in 12 patients and 44 patients, in the younger and older groups, respectively, and the curative resection rate was 77% and 59%, respectively. There were no deaths attributable to procedure-associated complications. Conclusions. ESD is an effective treatment for early esophageal cancer and is well tolerated by elderly patients.

FoxO1 as a double-edged sword in the pancreas: analysis of pancreas- and β-cell-specific FoxO1 knockout mice

Diabetes is characterized by an absolute or relative deficiency of pancreatic β-cells. New strategies to accelerate β-cell neogenesis or maintain existing β-cells are desired for future therapies against diabetes. We previously reported that forkhead box O1 (FoxO1) inhibits β-cell growth through a Pdx1-mediated mechanism. However, we also reported that FoxO1 protects against β-cell failure via the induction of NeuroD and MafA. Here, we investigate the physiological roles of FoxO1 in the pancreas by generating the mice with deletion of FoxO1 in the domains of the Pdx1 promoter (P-FoxO1-KO) or the insulin 2 promoter (β-FoxO1-KO) and analyzing the metabolic parameters and pancreatic morphology under two different conditions of increased metabolic demand: high-fat high-sucrose diet (HFHSD) and db/db background. P-FoxO1-KO, but not β-FoxO1-KO, showed improved glucose tolerance with HFHSD. Immunohistochemical analysis revealed that P-FoxO1-KO had increased β-cell mass due to increased islet number rather than islet size, indicating accelerated β-cell neogenesis. Furthermore, insulin-positive pancreatic duct cells were increased in P-FoxO1-KO but not β-FoxO1-KO. In contrast, db/db mice crossed with P-FoxO1-KO or β-FoxO1-KO showed more severe glucose intolerance than control db/db mice due to decreased glucose-responsive insulin secretion. Electron microscope analysis revealed fewer insulin granules in FoxO1 knockout db/db mice. We conclude that FoxO1 functions as a double-edged sword in the pancreas; FoxO1 essentially inhibits β-cell neogenesis from pancreatic duct cells but is required for the maintenance of insulin secretion under metabolic stress.

Overexpression of FoxO1 in the hypothalamus and pancreas causes obesity and glucose intolerance

Recent studies have revealed that insulin signaling in pancreatic β-cells and the hypothalamus is critical for maintaining nutrient and energy homeostasis, the failure of which are hallmarks of metabolic syndrome. We previously reported that forkhead transcription factor forkhead box-containing protein of the O subfamily (FoxO)1, a downstream effector of insulin signaling, plays important roles in β-cells and the hypothalamus when we investigated the roles of FoxO1 independently in the pancreas and hypothalamus. However, because metabolic syndrome is caused by the combined disorders in hypothalamus and pancreas, to elucidate the combined implications of FoxO1 in these organs, we generated constitutively active FoxO1 knockin (KI) mice with specific activation in both the hypothalamus and pancreas. The KI mice developed obesity, insulin resistance, glucose intolerance, and hypertriglyceridemia due to increased food intake, decreased energy expenditure, and impaired insulin secretion, which characterize metabolic syndrome. The KI mice also had increased hypothalamic Agouti-related protein and neuropeptide Y levels and decreased uncoupling protein 1 and peroxisome proliferator-activated receptor γ coactivator 1α levels in adipose tissue and skeletal muscle. Impaired insulin secretion was associated with decreased expression of pancreatic and duodenum homeobox 1 (Pdx1), muscyloaponeurotic fibrosarcoma oncogene homolog A (MafA), and neurogenic differentiation 1 (NeuroD) in islets, although β-cell mass was paradoxically increased in KI mice. Based on these results, we propose that uncontrolled FoxO1 activation in the hypothalamus and pancreas accounts for the development of obesity and glucose intolerance, hallmarks of metabolic syndrome.

Successful treatment of a patient with sepsis and liver abscess caused by Edwardsiella tarda

Edwardsiella tarda is a bacterium that is associated with both an asymptomatic oral carrier state and self-limiting diarrhoeal illness in humans. We herein report a case of sepsis and liver abscess caused by E. tarda and review the patients with E. tarda sepsis who presented at our hospital. An 85-year-old woman developed enterocolitis and sepsis caused by E. tarda. She was administered intensive care and thus was able to soon show a good recovery, however, she subsequently developed a liver abscess. During a complicated course, she continued to be treated with antibiotics and after a successful course was discharged on the 44th day after admission.

Perfusion CT is superior to angiography in predicting pancreatic necrosis in patients with severe acute pancreatitis

BACKGROUND

We performed perfusion computed tomography (P-CT) and angiography of the pancreas in patients with severe acute pancreatitis (SAP) and compared the usefulness of these two methods in predicting the development of pancreatic necrosis.

METHODS

We compared P-CT and angiography results taken within 3 days after symptom onset in 21 SAP patients. We divided the pancreas into three areas, the head, body, and tail, and examined each area for perfusion defects (via P-CT) and arterial vasospasms (by angiography). Three weeks later, all patients underwent contrast-enhanced CT to determine whether pancreatic necrosis had developed.

RESULTS

Of the 21 SAP patients, 16 exhibited perfusion defects, while 17 proved positive for vasospasms in at least one area. Fourteen patients developed pancreatic necrosis. Of the 63 pancreatic areas from the 21 SAP patients, perfusion defects appeared in 25 areas (39.7%), 24 of which showed vasospasms (96.0%). Angiography showed 33 areas with vasospasms (52.4%), of which 24 showed perfusion defects (72.7%). Of the 25 areas with perfusion defects, 21 developed pancreatic necrosis (84.0%). Of the 33 areas with vasospasms, 21 developed necrosis (63.6%). Pancreatic necrosis developed only in the areas positive both for perfusion defects and for vasospasms. No areas without perfusion defect or vasospasms developed pancreatic necrosis. P-CT predicted the development of pancreatic necrosis with significantly higher accuracy than angiography.

CONCLUSION

While both P-CT and angiography are useful in predicting the development of pancreatic necrosis in patients with SAP, P-CT appears to be more accurate for this purpose.

[Basilar artery occlusion due to embolism from the vertebral artery: three case reports]

Without early recanalization, it is well known that acute basilar artery occlusion almost always results in death or severe disability. We report three cases of basilar artery occlusion due to vertebral artery thrombo-embolism. In all cases, the cause of the strokes was artery to artery embolism from the vertebral artery origin. In case 1 and 3, despite complete occlusion of the vertebral artery origin, the thrombus was drained into the basilar artery through collateral flow from the external carotid artery. Atherosclerotic lesion of the vertebral artery origin is one of the main embolic sources of basilar artery, in which case, angioplasty or stent placement of the vertebral artery origin should be considered in addition to thrombolysis of the basilar artery.

Relationship between carotid intima-media thickness and silent cerebral infarction in Japanese subjects with type 2 diabetes

OBJECTIVE

We examined the relationship between intima-media thickness of common carotid artery (CCA-IMT) and silent cerebral infarction (SCI) with the magnetic resonance imaging (MRI) study in Japanese subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The brain MRI study and the carotid ultrasonography were performed in a total of 217 consecutive Japanese subjects with type 2 diabetes. Various risk factors for SCI were examined using multiple logistic analyses.

RESULTS

The SCI was found in 60.4% of the diabetic subjects. In the diabetic subjects, age, systolic blood pressure (SBP), pulse wave velocity, and CCA-IMT were significantly higher in the subjects with SCI than in those without it. Multiple logistic analyses indicated that age, SBP, and CCA-IMT were significant and independent risk factors of SCI in the diabetic subjects.

CONCLUSIONS

CCA-IMT, but not pulse wave velocity, was independently associated with SCI in Japanese subjects with type 2 diabetes.