Duodenal neuroendocrine tumor after bilateral breast cancer with type 1 neurofibromatosis: a case report

BACKGROUND

Young women with NF1 are at a high risk of developing breast cancer. Although they are at risk for abdominal tumors, such as gastrointestinal stromal tumors and neuroendocrine tumors, follow-up strategies for other tumors after breast cancer have not yet been established. Here, we present a case of duodenal neuroendocrine tumor found during follow-up after bilateral mastectomy for breast cancer with type 1 neurofibromatosis (NF1), for which pancreaticoduodenectomy (PD) and lymphadenectomy were performed.

CASE PRESENTATION

A 46-year-old woman with NF1 was referred to our hospital for treatment of a duodenal submucosal tumor. Her previous operative history included bilateral mastectomy for breast cancer: right total mastectomy and left partial mastectomy performed 9 and 5 years ago, respectively. Her daughter was confirmed to have NF1, but her parents were unclear. Although she had no recurrence or symptoms during the follow-up for her breast cancer, she wished to undergo 18-fluorodeoxyglucose-positron emission tomography (FDG-PET) for systemic screening. FDG-PET demonstrated FDG accumulation in the duodenal tumor with a maximum standardized uptake value of 5.78. Endoscopy revealed a 20-mm-diameter tumor in the second duodenal portion, and endoscopic biopsy suggested a NET G1. We performed PD and lymphadenectomy for complete. She was doing well without recurrence and was followed up with PET tomography-computed tomography.

CONCLUSIONS

Early detection of gastrointestinal tumors is difficult, because most of them are asymptomatic. Gastrointestinal screening is important for patients with NF1, and PD with lymphadenectomy is feasible for managing duodenal neuroendocrine tumors, depending on their size.

TWIST1 is a prognostic factor for neoadjuvant chemotherapy for patients with resectable pancreatic cancer: a preliminary study

Recent advances in the development of chemotherapies have helped improve the prognosis of pancreatic ductal adenocarcinoma (PDAC). However, predicting factors for the outcomes of chemotherapies (either gemcitabine or S-1) have not yet been established. We analyzed the expression of 4 major epithelial-to-mesenchymal transition-inducing transcription factors in 38 PDAC patients who received adjuvant chemotherapy after radical resection to examine the association with patients' prognoses. The TWIST1-positive group showed a significantly poorer prognosis than the TWIST1-negative group for both the relapse-free survival (median survival time [MST] of 8.9 vs. 18.5 months, P = 0.016) and the overall survival (MST of 15.2 vs. 33.4 months, P = 0.023). A multivariate analysis revealed that TWIST1 positivity was an independent prognostic factor for a poor response to adjuvant chemotherapies (hazard ratio 2.61; 95% confidence interval 1.10-6.79; P = 0.029). These results suggest that TWIST1 can be utilized as an important poor prognostic factor for radically resected PDAC patients with adjuvant chemotherapy, potentially including neoadjuvant therapy using these agents.

Legionella pneumonia immediately after recovery from COVID ‐19

We experienced a patient with Legionella pneumonia developing immediately after discharge from COVID‐19 recovery. Antibiotic treatment was successful. The source of Legiolella infection was proven to be bathtub water in this case. It is very important to accurately detect pathogens, particularly in the time of pandemics such as COVID‐19.

Development of Fluorophosphoramidate as a New Biocompatible Transformable Functional Group and its Application as a Phosphate Prodrug for Nucleoside Analogs

Synthetic phosphate-derived functional groups are important for controlling the function of bioactive molecules in vivo . Herein we describe the development of a new type of biocompatible phosphate analog, a fluorophosphoramidate (FPA) functional group that has characteristic P-F and P-N bonds. We found that FPA with a primary amino group was relatively unstable in aqueous solution and was converted to a monophosphate, while FPA with a secondary amino group was stable. Furthermore, by improving the molecular design of FPA, we developed a reaction in which a secondary amino group is converted to a primary amino group in the intracellular environment, and clarified that the FPA group functions as a phosphate prodrug of nucleoside. Various FPA-gemcitabine derivatives were synthesized and their anticancer activities were evaluated. One of the FPA-gemcitabine derivatives showed superior anticancer activity compared with gemcitabine and its ProTide prodrug, which methodology is widely used in various nucleoside analogs, including anti-cancer and anti-virus drugs.

A useful and safe method for retrieving a round metallic object from an airway

The endoscopic net forceps with the support of a laryngeal mask airway are a dependable choice for retrieving a round metallic object from an airway.

Epigenetic inactivation of IRX4 is responsible for acceleration of cell growth in human pancreatic cancer

Epigenetic gene silencing by aberrant DNA methylation is one of the important mechanisms leading to loss of key cellular pathways in tumorigenesis. Methyl-CpG-targeted transcriptional activation (MeTA) reactivates hypermethylation-mediated silenced genes in a different way from DNA-demethylating agents. Microarray coupled with MeTA (MeTA-array) identified seven commonly hypermethylation-mediated silenced genes in 12 pancreatic ductal adenocarcinoma (PDAC) cell lines. Among these, we focused on IRX4 (Iroquois homeobox 4) because IRX4 is located at chromosome 5p15.33 where PDAC susceptibility loci have been identified through genome-wide association study. IRX4 was greatly downregulated in all of the analyzed 12 PDAC cell lines by promoter hypermethylation. In addition, the IRX4 promoter region was found to be frequently and specifically hypermethylated in primary resected PDACs (18/28: 64%). Reexpression of IRX4 inhibited colony formation and proliferation in two PDAC cell lines, PK-1 and PK-9. In contrast, knockdown of IRX4 accelerated cell proliferation in an IRX4-expressing normal pancreatic ductal epithelial cell line, HPDE-1. Because IRX4 is a sequence-specific transcription factor, downstream molecules of IRX4 were pursued by microarray analyses utilizing tetracycline-mediated IRX4 inducible PK-1 and PK-9 cells; CRYAB, CD69, and IL32 were identified as IRX4 downstream candidate genes. Forced expression of these genes suppressed colony formation abilities for both PK-1 and PK-9. These results suggest that DNA methylation-mediated silencing of IRX4 contributes to pancreatic tumorigenesis through aberrant transcriptional regulation of several cancer-related genes.

Nanobubble technology to treat spinal cord ischemic injury

Background

Spinal cord ischemic injury is a severe complication of aortic surgery. We hypothesized that cerebrospinal fluid (CSF) oxygenation with nanobubbles after reperfusion could ameliorate spinal cord ischemic injury.

Methods

Twenty white Japanese rabbits were categorized into 4 groups of 5 rabbits each: sham group, with balloon catheter insertion into the aorta; ischemia group, with spinal cord ischemic injury by abdominal aortic occlusion; nonoxygenated group, with nonoxygenated artificial CSF irrigation after spinal cord ischemic injury; and oxygenated group, with oxygenated artificial CSF irrigation after spinal cord ischemic injury. At 48 hours after spinal cord ischemic injury, the modified Tarlov score to reflect hind limb movement was evaluated. The spinal cord was histopathologically examined by counting anterior horn cells, and microarray and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analyses were performed.

Results

The oxygenated group showed improved neurologic function compared with the ischemia and nonoxygenated groups (P < .01 and P = .019, respectively). Anterior horn neuron prevention in the sham, nonoxygenated, and oxygenated groups was confirmed (mean modified Tarlov score: sham, 9.2 ± 1.9; nonoxygenated, 10.2 ± 2.2; oxygenated, 10.4 ± 2.2; ischemia, 2.7 ± 2.7). Microarray analysis identified 644 genes with twofold or greater increased signals between the ischemia and sham groups. Thirty-three genes related to inflammatory response were enriched among genes differentially expressed between the oxygenated and ischemia groups. Interleukin (IL)-6 and tumor necrosis factor (TNF) expression levels were significantly lower in the oxygenated group compared with the ischemia group, while qRT-PCR showed lower IL-6 and TNF expression levels in the oxygenated group compared with the ischemia group (P < .05).

Conclusions

CSF oxygenation with nanobubbles after reperfusion can ameliorate spinal cord ischemic injury and suppress inflammatory responses in the spinal cord.

Photosensitizer With Illumination Enhances In Vivo Antitumor Effect of Anti-ROBO1 Immunotoxin on Maxillary Sinus Squamous Cell Carcinoma

BACKGROUND/AIM

Head and neck squamous cell carcinoma (HNSCC) is one of the most common types of cancer worldwide. Our study focused on the axon guidance receptor roundabout guidance receptor 1 (ROBO1) as a target for monoclonal antibody therapy of HNSCC. We previously showed that saporin-conjugated anti-ROBO1 (B5209B) immunotoxin (IT-ROBO1) enhanced cytotoxic effects on HNSCC cells in combination with the photosensitizer aluminum phthalocyanine disulphonate (AlPcS2a) and illumination. We examined the effects of this combination therapy in a mouse xenograft model.

MATERIALS AND METHODS

IT-ROBO1 was intraperitoneally administered to HSQ-89 (derived from Japanese maxillary sinus squamous carcinoma, RCB0789; RIKEN, Tsukuba, Japan) xenografted mice. After 3 days, AlPcS2a was injected subcutaneously around the tumor and the area was illuminated at 650 nm for 30 min. The growth of the tumor was evaluated and the effects on the tumor were examined.

RESULTS

Pronounced anti-tumor effects were elicited by the administration of IT-ROBO1 and AlPcS2a with light illumination on tumor size and pathological characteristics.

CONCLUSION

The results showed that photosensitizer treatment with illumination robustly enhanced the antitumor effect of the IT-ROBO1 immunotoxin.

Methylation-mediated silencing of the LIM homeobox 6 (LHX6) gene promotes cell proliferation in human pancreatic cancer

Epigenetic gene silencing by aberrant DNA methylation leads to loss of key cellular pathways in tumorigenesis. DNA methylation-mediated silenced genes in pancreatic cancer were searched for using the methyl-CpG targeted transcriptional activation (MeTA) method, and LHX6 (LIM homeobox 6), a transcription factor involved in embryogenesis and head development, was selected as a strong candidate gene. LHX6 was downregulated in most of the pancreatic cancer cell lines (83%, 10/12), mainly through promoter hypermethylation and histone deacetylation. Furthermore, LHX6 was methylated in primary pancreatic cancer specimens (57%, 16/28) in a tumor-specific manner. Re-expression of LHX6 inhibited colony formation and proliferation in LHX6 low-expressing pancreatic cancer cell lines, PK-1 and PK-9. In contrast, knockdown of LHX6 accelerated cell proliferation in LHX6 high-expressing pancreatic cancer cell lines, PCI-35 and MIA PaCa-2. In order to analyze LHX6 downstream genes, we performed microarray analyses using LHX6 inducible PK-1 and PK-9 and found that LHX6 induction upregulated several genes that had tumor suppressive functions. Among these, we focused on TFPI2 (Tissue factor pathway inhibitor-2) and found that TFPI2 was greatly downregulated in all twelve pancreatic cancer cell lines. Our present results suggest that epigenetic inactivation of LHX6 plays an important role in pancreatic tumorigenesis by promoting cell proliferation through aberrant transcriptional regulation of several cancer-related genes.

Progression of vascular remodeling in pulmonary vein obstruction

OBJECTIVES

Pulmonary vein obstruction (PVO) frequently occurs after repair of total anomalous pulmonary vein connection with progression of intimal hyperplasia from the anastomotic site toward upstream pulmonary veins (PVs). However, the understanding of mechanism in PVO progression is constrained by lack of data derived from a physiological model of the disease, and no prophylaxis has been established. We developed a new PVO animal model, investigated the mechanisms of PVO progression, and examined a new prophylactic strategy.

METHODS

We developed a chronic PVO model using infant domestic pigs by cutting and resuturing the left lower PV followed by weekly hemodynamic parameter measurement and angiographic assessment of the anastomosed PV. Subsequently, we tested a novel therapeutic strategy with external application of rapamycin-eluting film to the anastomotic site.

RESULTS

We found the pig PVO model mimicked human PVO hemodynamically and histopathologically. This model exhibited increased expression levels of Ki-67 and phospho-mammalian target of rapamycin in smooth muscle-like cells at the anastomotic neointima. In addition, contractile to synthetic phenotypic transition; that is, dedifferentiation of smooth muscle cells and mammalian target of rapamycin pathway activation in the neointima of upstream PVs were observed. Rapamycin-eluting films externally applied around the anastomotic site inhibited the activation of mammalian target of rapamycin in the smooth muscle-like cells of neointima, and delayed PV anastomotic stenosis.

CONCLUSIONS

We demonstrate the evidence on dedifferentiation of smooth muscle-like cells and mammalian target of rapamycin pathway activation in the pathogenesis of PVO progression. Delivery of rapamycin to the anastomotic site from the external side delayed PV anastomotic stenosis, implicating a new therapeutic strategy to prevent PVO progression.

Attempts to remodel the pathways of gemcitabine metabolism: Recent approaches to overcoming tumours with acquired chemoresistance

Gemcitabine is a cytidine analogue frequently used in the treatment of various cancers. However, the development of chemoresistance limits its effectiveness. Gemcitabine resistance is regulated by various factors, including aberrant genetic and epigenetic controls, metabolism of gemcitabine, the microenvironment, epithelial-to-mesenchymal transition, and acquisition of cancer stem cell properties. In many situations, results using cell lines offer valuable lessons leading to the first steps of important findings. In this review, we mainly discuss the factors involved in gemcitabine metabolism in association with chemoresistance, including nucleoside transporters, deoxycytidine kinase, cytidine deaminase, and ATP-binding cassette transporters, and outline new perspectives for enhancing the efficacy of gemcitabine to overcome acquired chemoresistance.

Multiple functions of S100A10, an important cancer promoter

The S100 group of calcium binding proteins is composed of 21 members that exhibit tissue/cell specific expressions. These S100 proteins bind a diverse range of targets and regulate multiple cellular processes, including proliferation, migration and differentiation. S100A10, also known as p11, binds mainly to annexin A2 and mediates the conversion of plasminogen to an active protease, plasmin. Higher S100A10 expression has been reported to link to worse outcome and/or chemoresistance in a number of cancer types in lung, breast, ovary, pancreas, gall bladder and colorectum and leukemia although some discrepancy was reported. In this review, we focused on the roles of the S100A10 in cancer. We summarized its biological functions, role in cancer progression, prognostic value and targeting of S100A10 for cancer therapy.

CD45+CD326+ Cells are Predictive of Poor Prognosis in Non-Small Cell Lung Cancer Patients

PURPOSE

The epithelial-to-mesenchymal transition, the major process by which some cancer cells convert from an epithelial phenotype to a mesenchymal one, has been suggested to drive chemo-resistance and/or metastasis in patients with cancer. However, only a few studies have demonstrated the presence of CD45/CD326 doubly-positive cells (CD45/CD326 DPC) in cancer. We deployed a combination of cell surface markers to elucidate the phenotypic heterogeneity in non-small cell lung cancer (NSCLC) cells and identified a new subpopulation that is doubly-positive for epithelial and non-epithelial cell-surface markers in both NSCLC cells and patients' malignant pleural effusions.

EXPERIMENTAL DESIGN

We procured a total of 39 patients' samples, solid fresh lung cancer tissues from 21 patients and malignant pleural effusion samples from 18 others, and used FACS and fluorescence microscopy to check their surface markers. We also examined the EGFR mutations in patients with known acquired EGFR mutations.

RESULTS

Our data revealed that 0.4% to 17.9% of the solid tumor tissue cells and a higher percentage of malignant pleural effusion cells harbored CD45/CD326 DPC expressing both epithelial and nonepithelial surface markers. We selected 3 EGFR mutation patients and genetically confirmed that the newly identified cell population really originated from cancer cells. We also found that higher proportions of CD45/CD326 DPC are significantly associated with poor prognosis.

CONCLUSIONS

In conclusion, varying percentages of CD45/CD326 DPC exist in both solid cancer tissue and malignant pleural effusion in patients with NSCLC. This CD45/CD326 doubly-positive subpopulation can be an important key to clinical management of patients with NSCLC.

Expression of SNAIL in accompanying PanIN is a key prognostic indicator in pancreatic ductal adenocarcinomas

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal cancer, mainly because of its invasive and metastatic characteristics. Pancreatic intraepithelial neoplasia (PanIN) is one of the major precursor lesions of PDAC. Although epithelial-to-mesenchymal transition (EMT) is known to play an important role for these malignant behaviors, the association between PanIN and EMT has not been clearly understood. Therefore, we explored possible molecules for regulation of EMT immunohistochemically. Using surgically resected specimens from 71 PDAC patients, expressions of SNAIL, SLUG, TWIST1, and ZEB1 were investigated in high-grade PanIN (HG-PanIN) and PDAC. Results demonstrated that PDAC accompanied by SNAIL-positive HG-PanIN showed a significantly better relapse-free survival (RFS) (median survival time (MST) of 11.3 months vs 4.4 months, P < 0.001) and overall survival overall survival (OS) (MST of 25.2 months vs 13.6 months, P < 0.001). In PDAC accompanied by SLUG-positive HG-PanIN, RFS and OS (P = 0.09 and P = 0.05) tended to have a better prognosis. In contrast, we could not find any significant prognostic benefits in the expression of TWIST1 or ZEB1 in PDAC accompanied by HG-PanIN. Our present results suggest that (1) EMT may play an important role in the development of PDAC from HG-PanIN, and (2) SNAIL may predict a distinct subgroup that shows a better prognosis.

Lymph node resection induces the activation of tumor cells in the lungs

Lymph node (LN) dissection is a crucial procedure for cancer staging, diagnosis and treatment, and for predicting patient survival. Activation of lung metastatic lesions after LN dissection has been described for head and neck cancer and breast cancer. Preclinical studies have reported that dissection of a tumor‐bearing LN is involved in the activation and rapid growth of latent tumor metastases in distant organs, but it is also important to understand how normal (non‐tumor‐bearing) LN resection influences secondary cancer formation. Here, we describe how the resection of tumor‐bearing and non‐tumor‐bearing LN affects distant metastases in MXH10/Mo‐lpr/lpr mice. Tumor cells were administered intravenously and/or intranodally into the right subiliac lymph node (SiLN) to create a mouse model of lung metastasis. Luciferase imaging revealed that tumor cells in the lung were activated after resection of the SiLN, irrespective of whether it contained tumor cells. No luciferase activity was detected in the lungs of mice that did not undergo LN resection (excluding the intravenous inoculation group). Our results indicate that resection of an LN can activate distant metastases regardless of whether the LN contains tumor cells. Hence, lung metastatic lesions are suppressed while metastatic LN are present but activated after LN resection. If this phenomenon occurs in patients with cancer, it is likely that lung metastatic lesions may be activated by elective LN dissection in clinical N0 cases. The development of minimally invasive cancer therapy without surgery would help to minimize the risk of activation of distant metastatic lesions by LN resection.

Treatment with Lactobacillus Retards the Tumor Growth of Head and Neck Squamous Cell Carcinoma Cells Inoculated in Mice

Bacteria have been used for more than a century to treat solid tumors. Because solid tumors generate an anaerobic environment, we evaluated the anti-tumor effect of the obligate anaerobe strain KK378, derived from Lactobacillus casei (L. casei), using mice bearing head and neck cancer. Wild-type L. casei is a nonpathogenic bacterium that is commonly used in foods. Moreover, patients with head and neck squamous cell carcinoma often have multiple cancers and cervical lymph node metastasis that can be directly sensed beneath the skin. To establish the animal model bearing head and neck cancer, we inoculated each of human squamous cell carcinoma cell lines, SAS, HSQ89, and HSC2, on the back skin of BALB/cSlc-nu/nu mice. After tumor formation, L. casei KK378 was administered directly into the tumor, and tumor size and serum cytokine levels were analyzed. Mice injected with 10⁸ cfu of L. casei KK378 showed reduction in tumor growth compared with PBS control; especially, the SAS tumor was significantly reduced (p = 0.008). Administered L. casei KK378 was detected in tumor tissues but not in normal tissues (liver, kidney, and lung) of SAS tumor-bearing mice, which was associated with increased blood cytokines (TNF-α, IFN-γ, IL-5, IL-10, and IL-12). Among these cytokines, the serum levels of IFN-γ and TNF-α were significantly increased (p < 0.05). In conclusion, L. casei KK378 infection may suppress tumor growth by inducing the host immune response. Direct injection of Lactobacillus into the tumor could be a potential strategy to treat head and neck squamous cell carcinoma.

S100A10 upregulation associates with poor prognosis in lung squamous cell carcinoma

S100A10 is one of the members of the S100 protein family and is a key plasminogen receptor. Its upregulation has been reported in many types of tumors. In lung cancer, an association between upregulation of S100A10 and poor prognoses has been reported only in adenocarcinoma. We pursued the possibility of significance in lung squamous cell carcinoma (SCC). We first examined S100A10 protein expression by immunohistochemistry in 120 primary resected lung SCCs; 33 (27.5%) tumors showed strong membranous-immunopositivity particularly at the invasive front, i.e., the cancer-cell surface in contact with the stroma. Expression levels were significantly associated with higher pathological TNM stage (P = 0.0119), tumor size (P = 0.0003), lymphatic invasion (P = 0.0005), lymph node metastasis (P = 0.0006), and poorer prognosis (P = 0.0064). Our present results suggest that high S100A10 expression of the lung SCC cells, particularly adjacent to stroma, plays an important role in tumor progression, probably caused by lymphatic invasion and nodal metastasis.

A Novel SDHB IVS2-2A>C Mutation Is Responsible for Hereditary Pheochromocytoma/Paraganglioma Syndrome

Pheochromocytomas and paragangliomas are neuroendocrine tumors which arise from adrenal medulla, and sympathetic or parasympathetic nerves, respectively. Hereditary cases afflicted by both or either pheochromocytomas and paragangliomas have been reported: these are called hereditary pheochromocytoma/paraganglioma syndromes (HPPS). Many cases of HPPS are caused by mutations of one of the succinate dehydrogenase (SDH) genes; mainly SDHB and SDHD that encode subunits for the mitochondrial respiratory chain complex II. In this study, we investigated mutations of SDH genes in six HPPS patients from four Japanese pedigrees using peripheral blood lymphocytes (from one patient with pheochromocytoma and five patients with neck paraganglioma) and tumor tissues (from two patients with paraganglioma). Results showed that all of these pedigrees harbor germline mutations in one of the SDH genes. In two pedigrees, a novel IVS2-2A>C mutation in SDHB, at the acceptor-site in intron 2, was found, and the tumor RNA of the patient clearly showed frameshift caused by exon skipping. Each of the remaining two pedigrees harbors a reported missense mutation, R242H in SDHB or G106D in SDHD. Importantly, all these mutations are heterozygous in constitutional DNAs, and two-hit mutations were evident in tumor DNAs. We thus conclude that the newly identified IVS2-2A>C mutation in SDHB is responsible for HPPS. The novel mutation revealed by our study may contribute to improvement of clinical management for patients with HPPS.

Abstract 4354: Methylation-mediated silenced PYCARD plays a key role in human prostate cancer

Epigenetic gene silencing by aberrant DNA methylation leads to loss of key cellular pathways in tumorigenesis. In order to analyze effects of DNA methylation in prostate cancer, we constructed LNCaP-derived human prostate cancer cells that can induce global reactivation of hypermethylated genes by the methyl-CpG targeted transcriptional activation (MeTA) method. In MeTA, a cassette construct of MBD2-derived methyl-CpG binding domain (MBD) with NFκB-derived transcriptional activation domain is transfected into cancer cells. Then expressed MBD domain specifically binds to the hypermethylated promoter regions, and NFκB transcriptional activation domain recruits p300/CREB-binding protein (CBP) and reactivates hypermethylation-mediated silenced genes. A cell proliferation assay indicated that MeTA suppressed the growth of LNCaP cells. Furthermore, both flow cytometry and TUNEL assays demonstrated that MeTA induced apoptosis. In order to search genes responsible for apoptosis, we performed gene expression microarray analysis of MeTA-uninduced and -induced LNCaP cells: Five genes encoding apoptosis-inducing factors upregulated two-fold or more in accordance with the induction of MeTA; PYCARD (PYD and CARD domain containing), TNFRSF25 (tumor necrosis factor receptor superfamily 25), HRK (harakiri, BCL2 interacting protein), BIK (BCL2 interacting killer), and CIDEA (cell death-inducing DFFA-like effector a). These genes also contained CpG islands (CGIs) within ± 1,000-bp of the transcription start site. We focused on PYCARD and TNFRSF25 because these two genes upregulated 10-fold or more in accordance with the induction of MeTA. We found that both genes were hypermethylated and showed low expression levels in LNCaP prostate cancer cells, whereas only PYCARD was unmethylated in RWPE-1 normal prostate epithelial cells. We further analyzed primary prostate cancer tissues and found tumor-specific promoter hypermethylation of PYCARD in 53.8% (7/13; P &lt; 0.01). These results suggest that methylation-mediated silencing of PYCARD contributes to escape from apoptosis in human prostate cancer, and MeTA may provide important clues to analyze changes in cancer cell phenotypes by DNA methylation alterations.

Citation Format: Shinichi Fukushige, Toshiya Miyauchi, Teppei Okubo, Koji Mitsuzuka, Yoichi Arai, Akira Horii. Methylation-mediated silenced PYCARD plays a key role in human prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4354. doi:10.1158/1538-7445.AM2017-4354

ABCB1 Is Upregulated in Acquisition of Taxane Resistance: Lessons from Esophageal Squamous Cell Carcinoma Cell Lines

Esophageal cancer is one of the common malignancies worldwide, particularly in eastern African and Asian countries including Japan. Taxane (paclitaxel or docetaxel) is one of the effective chemotherapeutic reagents for patients with esophageal cancer, but acquisition of chemoresistance frequently occurs; this is one of the most frequent causes for therapeutic failure. In this study, we established three taxane resistant esophageal squamous cell carcinoma cell lines and explored possible mechanisms for the acquisition of chemoresistance. Microarray analyses indicated that the ABCB1 (ATP binding cassette subfamily B member 1) gene was significantly upregulated in taxane resistant esophageal cancer cell lines. Moreover, we found that siRNA mediated ABCB1 knockdown successfully restored drug sensitivity in both paclitaxel and docetaxel resistant esophageal cancer cell lines. In conclusion, we propose that ABCB1 might play a pivotal role in acquisition of taxane resistance and could be a promising target for treatment of patients with esophageal cancer after acquisition of taxane resistance.

Targeted TET oxidase activity through methyl-CpG-binding domain extensively suppresses cancer cell proliferation

DNA methyltransferase (DNMT) inhibitors are epigenetic drugs used to treat myelodysplastic syndrome. They not only induce DNA demethylation but also have significant cytostatic and cytotoxic effects; however, the relationships between these characteristics have not been established yet due to the lack of a method to induce only DNA demethylation. Herein, we show that a fusion protein comprised of the methyl-CpG-binding domain (MBD) and the catalytic domain of Ten-eleven translocation protein 1 (TET1-CD) globally demethylates and upregulates a number of methylated genes. These upregulated genes frequently contained CpG islands (CGIs) within ± 1000 bp of the transcription start site (TSS). Interestingly, 65% of the genes upregulated fivefold or more by MBD-TET1-CDwt were also reactivated after treatment with a DNMT inhibitor, 5-azacytidine (Aza-CR), suggesting that gene reactivation by both methods primarily shares the same mechanism, DNA demethylation. In order to examine whether DNA demethylation affects the growth of cancer cells, we have established a tetracycline inducible system that can regulate the expression of MBD-TET1-CDwt in a prostate cancer cell line, LNCaP. The induction of MBD-TET1-CDwt demethylated and upregulated glutathione S-transferase pi 1 (GSTP1), one of the hypermethylated genes in prostate cancer. In accordance with the reactivation of methylated genes, induction of MBD-TET1-CDwt extensively suppressed the growth of LNCaP cells through G1/S arrest. These results clearly indicate that TET oxidase activity recruited at methyl-CpG sites through MBD induces reactivation of hypermethylated genes by DNA demethylation and allows us to analyze the effect of only global DNA demethylation in a wide variety of cancer cells.

Abstract 4432: Targeted TET oxidase activity through methyl-CpG binding domain extensively suppresses cancer cell proliferation

DNA demethylating agents are useful therapeutic drugs for human cancer; 5-aza-2’-deoxycytidine and 5-azacytidine for myelodysplastic syndrome are good examples. They not only induce DNA demethylation but also have significant cytostatic and cytotoxic effects. However, precise mechanisms for anticancer activity of these demethylating reagents have yet to be established, mainly due to the lack of method to induce only DNA demethylation. Here we show that a fusion protein comprising the methyl-CpG binding domain (MBD) and the catalytic domain of Ten-eleven translocation protein 1 (TET1-CD) globally demethylates and upregulates a number of methylated genes. Gene expression microarray analyses using human embryonic kidney cell line 293T indicate that cells expressing wild-type (wt) TET1 catalytic domain with MBD (MBD-TET1-CDwt) upregulates more genes than ones expressing TET1-CDwt without MBD (TET1-CDwt) or catalytically inactive TET1-CD mutant (mut) with MBD (MBD-TET1-CDmut) and their upregulated genes frequently contained CpG islands (CGIs) within ± 1,000-bp of the transcription start site (TSS). Interestingly, 65% of genes upregulated 5-fold or more by MBD-TET1-CDwt were also reactivated after treatment with 5-azacytidine, DNA demethylating agent. These results suggested a fact that gene reactivation by both methods was primarily based on DNA demethylation. In order to examine growth inhibitory effects of DNA demethylation to cancer cells, we utilized a tetracycline inducible system to regulate the expression of MBD-TET1-CDwt using a prostate cancer cell line. Induction of MBD-TET1-CDwt demethylated and upregulated the glutathione S-transferase pi 1 (GSTP1), one of the hypermethylated genes in prostate cancer. In accordance with reactivation of methylated genes, induction of MBD-TET1-CDwt extensively suppressed the growth of LNCaP cells. Flow cytometry analysis showed decreased cells in S phase and increased cells in G1 phase by MBD-TET1-CDwt expression. Our present results clearly indicate that TET oxidase activity recruited at methyl-CpG sites through MBD induces reactivation of hypermethylated genes by DNA demethylation, and that our methods allow us to analyze the effects of global DNA demethylation in a wide variety of cancer cells.

Citation Format: Shinichi Fukushige, Yasuhiko Mizuguchi, Kanchan Chakma, Yuriko Saiki, Akira Horii. Targeted TET oxidase activity through methyl-CpG binding domain extensively suppresses cancer cell proliferation. [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 4432.

Acquisition of chemoresistance to gemcitabine is induced by a loss-of-function missense mutation of DCK

The anti-tumor activity of gemcitabine (GEM) has been clinically proven in several solid tumors, including pancreatic cancer, biliary tract cancer, urinary bladder cancer, and non-small cell lung cancer. However, problems remain with issues such as acquisition of chemoresistance against GEM. GEM is activated after phosphorylation by deoxycytidine kinase (DCK) inside of the cell; thus, DCK inactivation is one of the important mechanisms for acquisition of GEM resistance. We previously investigated the DCK gene in multiple GEM resistant cancer cell lines and identified frequent inactivating mutations. In this study, we identified two crucial genetic alteration in DCK. (1) A total deletion of DCK in RTGBC1-TKB, an acquired GEM resistant cell line derived from a gall bladder cancer cell line TGBC1-TKB. (2) An E197K missense alteration of DCK in MKN28, a gastric cancer cell line; its acquired GEM resistant cancer cell line, RMKN28, showed a loss of the normal E197 allele. We introduced either normal DCK or altered DCK_E197K into RMKN28 and proved that only the introduction of normal DCK restored GEM sensitivity. Furthermore, we analyzed 104 healthy volunteers and found that none of them carried the same base substitution observed in MKN28. These results strongly suggest that (1) the E197K alteration in DCK causes inactivation of DCK, and that (2) loss of the normal E197 allele is the crucial mechanism in acquisition of GEM resistance in RMKN28.

Life and mental health of medical students after the Great East Japan Earthquake

Students of the Tohoku University School of Medicine experienced the Great East Japan Earthquake on March 11, 2011. We conducted a series of surveys to examine the relationships among their experiences and activities on the day of the earthquake, their physical, mental, and economic problems following the disaster, and how their problems changed over time. The initial survey was performed in April 2011, with three follow-up surveys in July 2011, February 2012, and April 2013. The initial survey focused on students' experiences and living conditions during the disaster, which contained questions on their locations and circumstances, family circumstances, lives after the earthquake, voluntary works, physical or mental health problems, and desire for counseling. The follow-up surveys included new items regarding their circumstances, changes in their health problems, and their desire for economic assistance. Students who answered the first survey to the 4th one, with response rates in the following bracket, were as follows: 472 (28.0%), 640 (29.9%), 681 (36.0%), and 678 (39.0%), respectively. Six months after the earthquake, about 20% having experienced physical and/or mental problems. Although there was a trend toward a reduction in suffering and health problems over time, some students' conditions remained unchanged or worsened. It is notable that students who had participated in voluntary activities, despite their own suffering of harm and distress, were identified as the group that required the closest attention. Our present results can be applied to appropriate supports for students in future large-scale disasters.

Molecular pathology of pancreatic cancer

By genomic and epigenomic screening techniques, substantial progress has been made in our understanding of pancreatic cancer. The comprehensive studies of the pancreatic cancer genome have revealed that most genetic alterations are identified to be associated with specific core signaling pathways including high-frequency mutated genes such as KRAS, CDKN2A, TP53, and SMAD4 along with several low-frequency mutated genes. Three types of histological precursors of pancreatic cancer: pancreatic intraepithelial neoplasia, mucinous cystic neoplasm, and intraductal papillary mucinous neoplasm, had been recognized by morphological studies and the recent genomic screening techniques revealed that each of these precursor lesions were associated with specific molecular alterations. In the familial pancreatic cancer cases, several responsible genes were discovered. Epigenetic changes also play an important role in the progression of pancreatic cancer. Several tumor suppressor genes were silenced due to aberrant promoter CpG island hypermethylation. Several genetically engineered mouse models, based on the Kras mutation, were created, and provided reliable tools to identify the key molecules responsible for the development or progression of pancreatic cancer.

Single-dose rosuvastatin ameliorates lung ischemia-reperfusion injury via upregulation of endothelial nitric oxide synthase and inhibition of macrophage infiltration in rats with pulmonary hypertension

OBJECTIVE

Lung ischemia-reperfusion (IR) injury during cardiopulmonary surgery is associated with postoperative morbidity and mortality, particularly in patients with pulmonary hypertension (PH). Using a rat model for monocrotaline-induced PH, we investigated the protective effect of rosuvastatin against IR injury in lungs affected by PH and attempted to elucidate its mechanism of action.

METHODS

Male Sprague-Dawley monocrotaline-treated rats were divided into 4 groups (n = 8-9): sham, control + IR, statin + IR, and statin + mevalonolactone + IR. Lung ischemia was induced by left pulmonary artery occlusion (1 hour), followed by reperfusion (4 hours). Rosuvastatin (2 mg/kg) was injected 18 hours before reperfusion and mevalonolactone (1 mg/kg) was injected immediately before reperfusion. The arterial oxygen tension/inspired oxygen fraction ratio was used as a measure of lung oxygenation. Left lung tissue was analyzed for the wet-to-dry lung weight ratio and protein expression of endothelial nitric oxide synthase (eNOS) and phospho-eNOS. Macrophage recruitment was assessed by CD68 immunostaining.

RESULTS

Our results showed that rosuvastatin decreased IR lung injury (control + IR vs statin + IR) in terms of the arterial oxygen tension/inspired oxygen fraction ratio (272 ± 43 vs 442 ± 13), wet-to-dry ratio (5.7 ± 0.7 vs 4.8 ± 0.6), and macrophage infiltration (8.0 ± 0.6/field vs 4.0 ± 0.5/field) (P < .05 for all). eNOS and phospho-eNOS were downregulated by IR, which was blocked by rosuvastatin. Effects of rosuvastatin were blunted by mevalonolactone.

CONCLUSIONS

Single-dose rosuvastatin decreased IR injury in lungs affected by PH via 2 anti-inflammatory mechanisms: preserving eNOS function and inhibiting macrophage infiltration.

Abstract 396: TET oxidase activity accumulated on methyl-CpG sites extensively upregulates methylated genes through DNA demethylation

Ten-Eleven Translocation (TET) proteins play an important role in regulating DNA methylation fidelity and their inactivation contributes to the DNA hypermethylation phenotype in cancer; they are Fe²+- and 2-oxoglutarate-dependent dioxygenases that successively oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) and these oxidized methylcytosines are important intermediates in the process of 5mC demethylation.

TET proteins convert 5mC to 5hmC in vitro, but it is difficult to explore the process of DNA demethylation and their effects on endogenous hypermethylated genes in cells. In this study, we tried to develop a system that accumulates TET oxidase activity at hypermethylated promoters. To accomplish this, we constructed a fusion protein-producing vector consisting of methyl-CpG binding domain (MBD) and TET1 catalytic domain (TET1 CD) and asked whether this fusion protein (MBD-TET1 CD) could lead to DNA demethylation and gene reactivation.

We first prepared DNA constructs that contain wild-type (wt) TET1 CD as well as catalytically inactive TET1 CD mutant (mut) with or without MBD from MBD2 protein and then transfected each construct into human embryonic kidney cell line 293T. We isolated stably transfected 293T cell lines and analyzed the expression of genes transcriptionally silenced by DNA hypermethylation using RT-PCR. Surprisingly, only plasmids containing TET1 CDwt reactivated silenced MAL, SOX17, TRH, MT1M, and MLH1 genes in a MBD dependent manner.

To clarify the mechanisms of the antisilencing activities in clones stably expressed MBD-TET1 CDwt, we examined the CpG islands in MAL, TRH, and MT1M promoters by genomic sequencing after bisulfite modifications. Almost all CpG sites were methylated in parental cell line 293T, a TET1 CDwt clone, a TET1 CDmut clone, and a MBD-TET1 CDmut clone. On the other hand, MBD-TET1 CDwt clones showed an extensive demethylation at CpG islands of all three genes. In addition, because bisulfite sequencing does not distinguish between 5mC and 5hmC, we converted 5hmC to glucosylated form and discriminated between 5mC and 5hmC using restriction enzymes MspI and HpaII. Quantitative real time PCR analysis clearly demonstrated that MBD-TET1 CDwt promoted demethylation at CpG sites with some 5hmC bases. We further examined the changes in global gene expression in stable cell lines containing different TET constructs by microarray analyses. All top 50 genes upregulated by MBD-TET1 CDwt-stably expressing cell lines contained CpG islands and interestingly, 43 of top 50 genes were also upregulated after treatment with DNA demethylating agent, 5-azacytidine.

These results suggest that specific recruitment of TET oxidase activity on hypermethylated gene promoters induces DNA demethylation and promotes reactivation of epigenetically silenced genes.

Citation Format: Shinichi Fukushige, Yasuhiko Mizuguchi, Akira Horii. TET oxidase activity accumulated on methyl-CpG sites extensively upregulates methylated genes through DNA demethylation. [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 396. doi:10.1158/1538-7445.AM2014-396

Abstract 4993: IFI27 and NOV, downstream regulated genes by S100A4, are playing important roles in pancreatic carcinogenesis

S100A4 is a member of the Ca2+-dependent S100 protein family, and positive association between S100A4-upregulation andmetastasis/invasion was reported. We reported a significant association between upregulation of S100A4 and perineural invasion in pancreatic cancer. Furthermore, siRNA-mediated knockdown of S100A4 promoted cell death mainly mediated by induction of apoptosis only in cancer cells with high expression of S100A4, and forced expression of S100A4 induced accelerated cell motility only in cancer cells with low expression. To explore the molecular mechanisms of cell motility after the forced expression of S100A4, we analyzed gene expression profiles and identified some candidate genes including IFI27 and NOV (CCN3) that are regulated by S100A4-upregulation, and we further focused on IFI27 and NOV. IFI27 showed significant upregulation after the forced expression of S100A4 and downregulation after siRNA mediated knockdown of S100A4, while NOV seemed to show an inverse relationship with S100A4. Using 93 primary resected tumors, we performed immunohistochemical analyses and identified significant positive association between S100A4 and IFI27 expressions. Although NOV did not show significant inverse-association, siRNA-mediated knockdown in high level expressing cells showed significant acceleration of cell motility. Clinicopathologic characteristics demonstrated positive associations between IFI27 expression and intrapancreatic neural invasion (P=0.0023) and negative associations between NOV expression and invasion pattern (P=0.017) were observed. Our present study suggests that IFI27 and NOV may be downstream regulated genes of S100A4 and that expressional changes may play important roles in invasion of pancreatic cancer.

Citation Format: Na Chen, Yuriko Saiki, Hitoshi Sekine, Makoto Sunamura, Shinichi Fukushige, Fuyuhiko Motoi, Shinichi Egawa, Michiaki Unno, Akira Horii. IFI27 and NOV, downstream regulated genes by S100A4, are playing important roles in pancreatic carcinogenesis. [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 4993. doi:10.1158/1538-7445.AM2014-4993

Characterization of functional transient receptor potential melastatin 8 channels in human pancreatic ductal adenocarcinoma cells

OBJECTIVE

Recently, the transient receptor potential melastatin 8 (TRPM8) channel has emerged as a putative biomarker for pancreatic ductal adenocarcinoma (PDA). This study aimed to evaluate the expression of TRPM8 and its modulation by specific agonists and antagonists in PDA cells.

METHODS

We examined the protein expression of TRPM8 in 3 different PDA cell lines and compared it with a nontumoral epithelial cell line of human pancreatic origin using Western blotting and immunocytochemical analysis. To assess the function of TRPM8 channels, we measured the TRPM8 currents in whole-cell mode of the patch clamp technique. To explore the putative involvement of TRPM8 in cell migration, we investigated the motility of PDA cells using the scratch-wound assay.

RESULTS

Pancreatic ductal adenocarcinoma cells express functional plasma membrane TRPM8 channels, which are responsive after exposure to agonists (menthol and icilin) and antagonists N-(3-aminopropyl)-2-{[(3-methylphenyl) methyl]oxy}-N-(2-thienylmethyl)benzamide hydrochloride salt. The silencing of TRPM8 expression by small interfering RNA augments the migration of PDA cells. Conversely, the activated form of TRPM8 inhibits PDA cell motility.

CONCLUSIONS

An unglycosylated TRPM8 protein is expressed and is functional in the membrane of PDA cells. Transient receptor potential melastatin 8 inhibits the migration of PDA cells, suggesting a putative role as a biomarker or target for this channel for PDA therapy.

A New Assay Using Surface Plasmon Resonance (SPR) to Determine Binding of theLactobacillus acidophilusGroup to Human Colonic Mucin

A new binding assay to investigate the mechanism of adhesion of lactic acid bacteria to the human intestine was established by the surface plasmon resonance technique using a biosensor BIACORE1000. Cells of 26 strains of the Lactobacillus acidophilus group as analytes were eluted onto a sensor chip on which were immobilized biotinylated A-trisaccharide polymer probes having human A-type antigen [(GalNAcalpha1-3(Fucalpha1-2)Gal)-] or human colonic mucin of blood type A (HCM-A) as ligands. In the first screening, high adhesive affinity to the A-trisaccharide BP-probe was observed in L. acidophilus OLL2769, L. crispatus JCM8778, LA205 and LA206. In the second screening, which used HCM-A, only L. acidophilus OLL2769 and L. crispatus JCM8778 were selected as adhesive strains with specific binding ability to human A-antigen. The results indicated that some strains of the L. acidophilus group could recognize and bind the sugar chain of A-antigen structure on HCM.

S100A4 is frequently overexpressed in lung cancer cells and promotes cell growth and cell motility

S100A4, a small calcium-binding protein belonging to the S100 protein family, is commonly overexpressed in a variety of tumor types and is widely accepted to associate with metastasis by regulating the motility and invasiveness of cancer cells. However, its biological role in lung carcinogenesis is largely unknown. In this study, we found that S100A4 was frequently overexpressed in lung cancer cells, irrespective of histological subtype. Then we performed knockdown and forced expression of S100A4 in lung cancer cell lines and found that specific knockdown of S100A4 effectively suppressed cell proliferation only in lung cancer cells with S100A4-overexpression; forced expression of S100A4 accelerated cell motility only in S100A4 low-expressing lung cancer cells. PRDM2 and VASH1, identified as novel upregulated genes by microarray after specific knockdown of S100A4 in pancreatic cancer, were also analyzed, and we found that PRDM2 was significantly upregulated after S100A4-knockdown in one of two analyzed S100A4-overexpressing lung cancer cells. Our present results suggest that S100A4 plays an important role in lung carcinogenesis by means of cell proliferation and motility by a pathway similar to that in pancreatic cancer.

Loss of NDRG2 expression activates PI3K-AKT signalling via PTEN phosphorylation in ATLL and other cancers

Constitutive phosphatidylinositol 3-kinase (PI3K)-AKT activation has a causal role in adult T-cell leukaemia-lymphoma (ATLL) and other cancers. ATLL cells do not harbour genetic alterations in PTEN and PI3KCA but express high levels of PTEN that is highly phosphorylated at its C-terminal tail. Here we report a mechanism for the N-myc downstream-regulated gene 2 (NDRG2)-dependent regulation of PTEN phosphatase activity via the dephosphorylation of PTEN at the Ser380, Thr382 and Thr383 cluster within the C-terminal tail. We show that NDRG2 is a PTEN-binding protein that recruits protein phosphatase 2A (PP2A) to PTEN. The expression of NDRG2 is frequently downregulated in ATLL, resulting in enhanced phosphorylation of PTEN at the Ser380/Thr382/Thr383 cluster and enhanced activation of the PI3K-AKT pathway. Given the high incidence of T-cell lymphoma and other cancers in NDRG2-deficient mice, PI3K-AKT activation via enhanced PTEN phosphorylation may be critical for the development of cancer.

Suppressed expression of NDRG2 correlates with poor prognosis in pancreatic cancer

Pancreatic cancer is a highly lethal disease with a poor prognosis; the molecular mechanisms of the development of this disease have not yet been fully elucidated. N-myc downstream regulated gene 2 (NDRG2), one of the candidate tumor suppressor genes, is frequently downregulated in pancreatic cancer, but there has been little information regarding its expression in surgically resected pancreatic cancer specimens. We investigated an association between NDRG2 expression and prognosis in 69 primary resected pancreatic cancer specimens by immunohistochemistry and observed a significant association between poor prognosis and NDRG2-negative staining (P=0.038). Treatment with trichostatin A, a histone deacetylase inhibitor, predominantly up-regulated NDRG2 expression in the NDRG2 low-expressing cell lines (PANC-1, PCI-35, PK-45P, and AsPC-1). In contrast, no increased NDRG2 expression was observed after treatment with 5-aza-2' deoxycytidine, a DNA demethylating agent, and no hypermethylation was detected in either pancreatic cancer cell lines or surgically resected specimens by methylation specific PCR. Our present results suggest that (1) NDRG2 is functioning as one of the candidate tumor-suppressor genes in pancreatic carcinogenesis, (2) epigenetic mechanisms such as histone modifications play an essential role in NDRG2 silencing, and (3) the expression of NDRG2 is an independent prognostic factor in pancreatic cancer.

DNA methylation in cancer: a gene silencing mechanism and the clinical potential of its biomarkers

Initiation and progression of human cancer not only depends on genetic alterations but also on epigenetic changes such as DNA methylation and histone modifications. Aberrant DNA hypermethylation in the promoter regions of genes is the most well-defined epigenetic change in tumors and is associated with inappropriate gene silencing. This feature can be utilized to search for tumor-specific DNA methylation biomarkers and to examine candidate DNA biomarkers for clinical use. DNA methylation biomarker is defined as a molecular target that undergoes DNA methylation changes in carcinogenesis. Such a biomarker is useful for early detection of cancer, predicting and/or monitoring the therapeutic response, and detection of recurrent cancer. In this review, we describe the mechanism that establishes and maintains DNA methylation patterns as well as the mechanism of aberrant gene silencing in cancer, and then we introduce methods to isolate the DNA methylation biomarkers. We also summarize the current status of clinical implementation for some of the most widely studied and well-validated DNA methylation biomarkers, including tissue factor pathway inhibitor 2 (TFPI2), septin 9 (SEPT9), glutathione S-transferase pi 1 (GSTP1), and O(6)-methylguanine-DNA methyltransferase (MGMT), and assess the clinical potential of these biomarkers for risk assessment, early diagnosis, prognosis, treatment, and the prevention of cancer. Finally we describe the possible involvement of 5-hydroxymethylcytosine in cancer; this is a recently discovered 5-methylcytosine oxidation derivative and might have a diagnostic potential in certain cancers. Abnormal DNA methylations are leading candidates for the development of specific markers for cancer diagnosis and therapy.

p190A RhoGAP is involved in EGFR pathways and promotes proliferation, invasion and migration in lung adenocarcinoma cells

Overcoming acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‑TKIs) is an emerging issue in lung cancer treatment. We report evidence that a GTPase-activating protein, p190-A RhoGAP (p190), is a potential molecular target for the treatment of lung adenocarcinoma. We documented inhibition of phosphorylation of p190 by EGFR-TKI treatment in lung adenocarcinoma cell lines. Small interfering RNA-mediated knockdown of p190 leads lung adenocarcinoma cells to growth suppression and to inhibition of invasion/migration through inducing cell cycle arrest but not apoptosis. These findings were observed not only in EGFR-TKI-sensitive cells but also in EGFR-TKI-resistant cells; even in cell lines harboring K-ras mutations. The mechanism of this inhibitory effect on growth and invasion/migration was Ras inactivation through disrupting the p190-A RhoGAP/p120RasGAP complex. In addition, a high level of p190 mRNA expression was observed in majority of surgically obtained tissue from lung adenocarcinoma patients. Overexpression of p190 mRNA associated with poor disease-free survival. The results suggest that overexpression of p190 mRNA may be involved in the carcinogenesis of lung adenocarcinoma. These findings indicate that p190 is a possible molecular target for treatment of lung adenocarcinoma.

Abstract 4233: MeTA-array, a useful method to identify genes transcriptionally silenced by tumor-specific hypermethylation in cancer

Aberrant DNA hypermethylation, the most well defined epigenetic changes in cancer, is associated with inappropriate gene silencing and this feature is utilized to search for tumor-specific DNA methylation biomarkers. Methyl-CpG binding domain (MBD) proteins (MBPs) can elicit the repressive potential of methylated DNA and play a major role in gene silencing mechanisms. Therefore, if the genes governed by MBPs are specifically reactivated, it should be possible to uncover them. We developed a method termed “methyl-CpG targeted transcriptional activation (MeTA)” that employs a fusion gene comprised of the MBD from MBD2 and the NFκB transcriptional activation domain. Microarray coupled with MeTA (MeTA-array) provides not only the information about methylated genes but also the one about transcriptional repression in a single experiment.

We first applied either MeTA or a conventional DNA demethylating agent, 5-aza-cytidine (Aza-CR), to a human embryonic kidney cell line 293T and analyzed gene expression profiles by microarray; 138 and 202 genes that are upregulated 5-fold or more were identified by MeTA and Aza-CR, respectively. ChIP-Seq analysis indicated that MeTA-inducing protein containing MBD binds to more than 80% of genes selected by MeTA-array. We found associations between expressional restorations by MeTA, methylation status, and NFκB (AD)-MBD fusion protein bindings in CpG islands (CGIs) around the transcription start site of the genes. Importantly, MeTA can upregulate genes meeting the stringent criteria of CGIs defined by Takai and Jones (Proc Natl Acad Sci USA 99: 3740-3745, 2002) at the promoter region at higher frequency; 109 of 138 (79.0%) genes in MeTA vs. 121 of 202 (59.9%) genes in Aza-CR.

We further applied MeTA-array to 12 pancreatic cancer cell lines along with HPDE (normal pancreatic ductal epithelial cell line) and identified 31 candidate tumor-specific hypermethylated genes; 26 of them have never been reported previously using the conventional DNA demethylating agents. Seven genes, IRX4, LHX6, NEFH, NEFL, NEFM, NPTX2 and TMEM204 were further examined their methylation statuses by MSP, and we found that 100% (21/21) of IRX4, 62% (13/21) of LHX6, 100% (21/21) of NEFH, 100% (21/21) of NEFL, 100% (21/21) of NEFM, 100% (21/21) of NPTX2 and 95% (20/21) of TMEM204 were methylated in our series of pancreatic cancer cell lines. Furthermore, 68% (15/22) of IRX4, 55% (12/22) of LHX6, 55% (12/22) of NEFH, 59% (23/22) of NEFL, 82% (18/22) of NEFM and 82% (18/22) of NPTX2 were also hypermethylated in primary pancreatic cancer specimens in a tumor-specific manner. Our results suggest that MeTA-array is a highly efficient method to identify methylation-mediated transcriptionally silenced genes in human cancer.

Citation Format: Shinichi Fukushige, Akira Horii. MeTA-array, a useful method to identify genes transcriptionally silenced by tumor-specific hypermethylation in cancer. [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 4233. doi:10.1158/1538-7445.AM2013-4233

S100A4, frequently overexpressed in various human cancers, accelerates cell motility in pancreatic cancer cells

S100A4, a member of the Ca(2+) dependent S100 protein family, is reported to associate with metastasis through regulation of the motility and invasiveness of cancer cells. A high level of S100A4 protein has been reported in a variety of cancers, including pancreatic cancer. However, its biological role in pancreatic carcinogenesis is largely unknown. We previously reported that S100A4 is frequently overexpressed and that RNAi-mediated knockdown induces apoptosis and suppression of cell growth, motility, and invasiveness. In this study, we analyzed the effects of forced expression of S100A4 in pancreatic cancer cell lines without S100A4-upregulation. We used two cell lines without upregulation of S100A4 (PCI-35 and PCI-43) as well as two cell lines with highly upregulated S100A4 as the control (MIA PaCa-2 and PAN-07-JCK). Cells did not show acceleration of their growth and invasiveness after forced expression of S100A4, but remarkable acceleration of cell motility was observed only in PCI-35 and PCI-43. We further performed microarray analyses using PCI-35 and PCI-43 with and without forced expression of S100A4 and identified 72 and 18 genes that were 2-fold or more upregulated or downregulated, respectively, in both cell lines after forced expression of S100A4. Our results suggest that S100A4 is crucial for cell motility in pancreatic cancer and that some downstream genes may play important roles in cell motility.

miR-34a is downregulated in cis-diamminedichloroplatinum treated sinonasal squamous cell carcinoma patients with poor prognosis

For the purpose of analyzing mechanisms related to the cis-diamminedichloroplatinum resistance in head and neck squamous cell carcinoma, we analyzed RPMI2650 and its derived previously established cis-diamminedichloroplatinum resistant cell line RPMI2650CR. To identify resistant phenotype-related microRNAs, we compared microRNA expressions between RPMI2650CR and RPMI2650 by microarray. One of the microRNAs as downregulated, miR-34a, was further investigated. Decreased expression of miR-34a in RPMI2650CR was confirmed by quantitative reverse transcription-polymerase chain reaction, but introduction of the miR-34a precursor into RPMI2650CR or the inhibitor of miR-34a into RPMI2650 did not change cis-diamminedichloroplatinum sensitivities. However, 24 patients with sinonasal squamous cell carcinomas treated with intra-arterial infusion of cis-diamminedichloroplatinum showed a significant association between decreased expression of miR-34a and poor disease specific survival (P = 0.0015), poor disease free survival (P = 0.0019), and poor local control rates (P = 0.017) (median follow-up period: 53 months). Furthermore, multivariate analyses demonstrated significant associations between miR-34a expression and the hazard ratios of disease free survival at 0.005 (95% confidence interval [CI] 0.00-0.29, P = 0.011) and local control rate at 0.008 (95% CI 0.00-0.44, P = 0.019), although other parameters such as age, gender, treatment method, T and N stages did not show any similar association. These results strongly suggest that miR-34a expression can be an independent prognostic biomarker in patients with sinonasal squamous cell carcinoma who are undergoing treatment with cis-diamminedichloroplatinum.

Potential utility of eGFP-expressing NOG mice (NOG-EGFP) as a high purity cancer sampling system

PURPOSE

It is still technically difficult to collect high purity cancer cells from tumor tissues, which contain noncancerous cells. We hypothesized that xenograft models of NOG mice expressing enhanced green fluorescent protein (eGFP), referred to as NOG-EGFP mice, may be useful for obtaining such high purity cancer cells for detailed molecular and cellular analyses.

METHODS

Pancreato-biliary cancer cell lines were implanted subcutaneously to compare the tumorigenicity between NOG-EGFP mice and nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. To obtain high purity cancer cells, the subcutaneous tumors were harvested from the mice and enzymatically dissociated into single-cell suspensions. Then, the cells were sorted by fluorescence-activated cell sorting (FACS) for separation of the host cells and the cancer cells. Thereafter, the contamination rate of host cells in collected cancer cells was quantified by using FACS analysis. The viability of cancer cells after FACS sorting was evaluated by cell culture and subsequent subcutaneous reimplantation in NOG-EGFP mice.

RESULTS

The tumorigenicity of NOG-EGFP mice was significantly better than that of NOD/SCID mice in all of the analyzed cell lines (p < 0.01). Sorting procedures enabled an almost pure collection of cancer cells with only slight contamination by host cells. Reimplantation of the sorted cancer cells formed tumors again, which demonstrated that cell viability after sorting was well maintained.

CONCLUSIONS

This method provides a novel cancer sampling system for molecular and cellular analysis with high accuracy and should contribute to the development of personalized medicine.

Methylation of death-associated protein kinase is associated with cetuximab and erlotinib resistance

Anti-EGFR therapy is among the most promising molecular targeted therapies against cancer developed in the past decade. However, drug resistance eventually arises in most, if not all, treated patients. Emerging evidence has linked epigenetic changes, such as DNA methylation at CpG islands, to the development of resistance to multiple anticancer drugs. In addition, genes that are differentially methylated have increasingly been appreciated as a source of clinically relevant biomarker candidates. To identify genes that are specifically methylated during the evolution of resistance to anti-EGFR therapeutic agents, we performed a methylation-specific array containing a panel of 56 genes that are commonly known to be regulated through promoter methylation in two parental non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC) cell lines and their resistant derivatives to either erlotinib or cetuximab. We found that death-associated protein kinase (DAPK) was hypermethylated in drug-resistant derivatives generated from both parental cell lines. Restoration of DAPK into the resistant NSCLC cells by stable transfection re-sensitized the cells to both erlotinib and cetuximab. Conversely, siRNA-mediated knockdown of DAPK induced resistance in the parental sensitive cells. These results demonstrate that DAPK plays important roles in both cetuximab and erlotinib resistance, and that gene silencing through promoter methylation is one of the key mechanisms of developed resistance to anti-EGFR therapeutic agents. In conclusion, DAPK could be a novel target to overcome resistance to anti-EGFR agents to improve the therapeutic benefit, and further evaluation of DAPK methylation as a potential biomarker of drug response is needed.