Polyunsaturated fatty acids-induced ferroptosis suppresses pancreatic cancer growth

Despite recent advances in science and medical technology, pancreatic cancer remains associated with high mortality rates due to aggressive growth and no early clinical sign as well as the unique resistance to anti-cancer chemotherapy. Current numerous investigations have suggested that ferroptosis, which is a programed cell death driven by lipid oxidation, is an attractive therapeutic in different tumor types including pancreatic cancer. Here, we first demonstrated that linoleic acid (LA) and α-linolenic acid (αLA) induced cell death with necroptotic morphological change in MIA-Paca2 and Suit 2 cell lines. LA and αLA increased lipid peroxidation and phosphorylation of RIP3 and MLKL in pancreatic cancers, which were negated by ferroptosis inhibitor, ferrostatin-1, restoring back to BSA control levels. Similarly, intraperitoneal administration of LA and αLA suppresses the growth of subcutaneously transplanted Suit-2 cells and ameliorated the decreased survival rate of tumor bearing mice, while co-administration of ferrostatin-1 with LA and αLA negated the anti-cancer effect. We also demonstrated that LA and αLA partially showed ferroptotic effects on the gemcitabine-resistant-PK cells, although its effect was exerted late compared to treatment on normal-PK cells. In addition, the trial to validate the importance of double bonds in PUFAs in ferroptosis revealed that AA and EPA had a marked effect of ferroptosis on pancreatic cancer cells, but DHA showed mild suppression of cancer proliferation. Furthermore, treatment in other tumor cell lines revealed different sensitivity of PUFA-induced ferroptosis; e.g., EPA induced a ferroptotic effect on colorectal adenocarcinoma, but LA or αLA did not. Collectively, these data suggest that PUFAs can have a potential to exert an anti-cancer effect via ferroptosis in both normal and gemcitabine-resistant pancreatic cancer.

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.

Ablation of Dual-Specificity Phosphatase 6 Protects against Nonalcoholic Fatty Liver Disease via Cytochrome P450 4A and Mitogen-Activated Protein Kinase

Dual-specificity phosphatase 6 (DUSP6) is a specific phosphatase for mitogen-activated protein kinase (MAPK). This study used a high-fat diet (HFD)-induced murine nonalcoholic fatty liver disease model to investigate the role of DUSP6 in this disease. Wild-type (WT) and Dusp6-haploinsufficiency mice developed severe obesity and liver pathology consistent with nonalcoholic fatty liver disease when exposed to HFD. In contrast, Dusp6-knockout (KO) mice completely eliminated these phenotypes. Furthermore, primary hepatocytes isolated from WT mice exposed to palmitic and oleic acids exhibited abundant intracellular lipid accumulation, whereas hepatocytes from Dusp6-KO mice showed minimal lipid accumulation. Transcriptome analysis revealed significant down-regulation of genes encoding cytochrome P450 4A (CYP4A), known to promote ω-hydroxylation of fatty acids and hepatic steatosis, in Dusp6-KO hepatocytes compared with that in WT hepatocytes. Diminished CYP4A expression was observed in the liver of Dusp6-KO mice compared with WT and Dusp6-haploinsufficiency mice. Knockdown of DUSP6 in HepG2, a human liver-lineage cell line, also promoted a reduction of lipid accumulation, down-regulation of CYP4A, and up-regulation of phosphorylated/activated MAPK. Furthermore, inhibition of MAPK activity promoted lipid accumulation in DUSP6-knockdown HepG2 cells without affecting CYP4A expression, indicating that CYP4A expression is independent of MAPK activation. These findings highlight the significant role of DUSP6 in HFD-induced steatohepatitis through two distinct pathways involving CYP4A and MAPK.

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.

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.

The transcription factor BACH1 at the crossroads of cancer biology: From epithelial-mesenchymal transition to ferroptosis

The progression of cancer involves not only the gradual evolution of cells by mutations in DNA but also alterations in the gene expression induced by those mutations and input from the surrounding microenvironment. Such alterations contribute to cancer cells' abilities to reprogram metabolic pathways and undergo epithelial-to-mesenchymal transition (EMT), which facilitate the survival of cancer cells and their metastasis to other organs. Recently, BTB and CNC homology 1 (BACH1), a heme-regulated transcription factor that represses genes involved in iron and heme metabolism in normal cells, was shown to shape the metabolism and metastatic potential of cancer cells. The growing list of BACH1 target genes in cancer cells reveals that BACH1 promotes metastasis by regulating various sets of genes beyond iron metabolism. BACH1 represses the expression of genes that mediate cell–cell adhesion and oxidative phosphorylation but activates the expression of genes required for glycolysis, cell motility, and matrix protein degradation. Furthermore, BACH1 represses FOXA1 gene encoding an activator of epithelial genes and activates SNAI2 encoding a repressor of epithelial genes, forming a feedforward loop of EMT. By synthesizing these observations, we propose a “two-faced BACH1 model”, which accounts for the dynamic switching between metastasis and stress resistance along with cancer progression. We discuss here the possibility that BACH1-mediated promotion of cancer also brings increased sensitivity to iron-dependent cell death (ferroptosis) through crosstalk of BACH1 target genes, imposing programmed vulnerability upon cancer cells. We also discuss the future directions of this field, including the dynamics and plasticity of EMT.

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.

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.

BACH1 Promotes Pancreatic Cancer Metastasis by Repressing Epithelial Genes and Enhancing Epithelial-Mesenchymal Transition

Pancreatic ductal adenocarcinoma (PDAC) is among the cancers with the poorest prognoses due to its highly malignant features. BTB and CNC homology 1 (BACH1) has been implicated in RAS-driven tumor formation. We focused on the role of BACH1 in PDAC, more than 90% of which have KRAS mutation. Knockdown of BACH1 in PDAC cell lines reduced cell migration and invasion, in part, by increasing E-cadherin expression, whereas its overexpression showed opposite effects. BACH1 directly repressed the expression of FOXA1 that is known to activate the expression of CDH1 encoding E-cadherin and to inhibit epithelial-to-mesenchymal transition. BACH1 also directly repressed the expression of genes important for epithelial cell adhesion including CLDN3 and CLDN4. In a mouse orthotopic implantation model, BACH1 was required for the high metastatic ability of AsPC-1 cells. IHC analysis of clinical specimens with a newly developed anti-BACH1 mAb revealed that high expression of BACH1 is a poor prognostic factor. These results suggest that the gene regulatory network of BACH1 and downstream genes including CDH1 contribute to the malignant features of PDAC by regulating epithelial-to-mesenchymal transition. SIGNIFICANCE: Greater understanding of the gene regulatory network involved in epithelial-to-mesenchymal transition of pancreatic cancer cells will provide novel therapeutic targets and diagnostic markers.

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.

92Transcatheter aortic valve implantation improves cerebral blood flow and cognitive function in elderly patients with aortic stenosis - Brain perfusion SPECT imaging study

Background

Cognitive impairment and depression are commonly noted in elderly frail patients with severe aortic stenosis (AS). However, their mechanisms and reversibility after treatment remain remain to be examined.

Purpose

In this study, we examined whether transcatheter aortic valve implantation (TAVI) increases cerebral blood flow (CBF) in cognitive/emotional brain areas, such as the hippocampus, in the elderly patients with severe AS.

Methods

We examined consecutive 15 right-handed patients with severe AS who were eligible for TAVI (median age 83.2 years, 12 (80%) women). We evaluated the following assessments both at baseline and 3 months after TAVI. Frailty was evaluated based on Fried scale, which consists of 5 items, including gait speed, cognitive function, weight loss, exhaustion, and inactivity. Frail and pre-frail were defined as greater than 3 and 1∼2 in the scale, respectively. Cognitive and emotional status were evaluated with Logical Memory (LM) II, Mini Mental State Examination (MMSE), and geriatric depression scale (GDS). Lower LM II (less than 4 points) and MMSE (less than 24 points) and higher GDS (more than 6 points) indicate worse memory, general cognitive function, and depressive symptoms, respectively. CBF images were recorded with 99mTc single-photon emission computed tomography and were analyzed using SPM12. Briefly, CBF images were firstly normalized to the standard Montreal Neurological Institute space. Then, a voxel-wise parametric analysis was conducted between normalized CBF images at baseline and those after TAVI (P<0.005 at each voxel). Continuous variables were presented as mean ± standard error (SE). Normality was assessed using the Shapiro-Wilk test. Continuous variables were compared with the use of paired t test. Linear mixed-model analysis was performed to evaluate changes in neuropsychological tests and CBF over time.

Results

In the present study, all patients were not robust but pre-frail (47.3%) or frail (53.7%). LM II score was significantly improved at 3 months after TAVI compared with baseline (baseline, 8.7 vs. 3 months, 13.8, P<0.01) (Figure A), whereas no significant changes in MMSE or GDS scores were noted (baseline, 24.6 vs. 3 months, 25.2 for MMSE; baseline, 4.3 vs. 3 months, 4.2 for GDS). Importantly, although no patients showed clinical symptoms or signs for transient ischemic attack or stroke after TAVI, CBF in the local regions, including the right hippocampus, was significantly increased after TAVI compared with baseline (P<0.005 at each voxel) (green arrowheads) (Figure B). Furthermore, CBF in the right hippocampus were positively correlated with LM II scores (P=0.017) (Figure C).

Figure 1

Conclusions

These results provide the first evidence that TAVI improves cerebral perfusion (especially that in the hippocampus) and cognitive functions in elderly patients with severe AS.

P889Clinical significance of four-dimensional flow magnetic resonance imaging measurement of turbulent kinetic energy for hypertrophic obstructive cardiomyopathy

Purpose

The aims of this study were to investigate the relationship between TKE value and echocardiographic findings, clinical symptoms and evaluate the usefulness of 4D flow MRI to distinguish hypertrophic obstructive cardiomyopathy (HOCM) from non-obstructive HCM (HNCM).

Methods

From April 2018 to January 2019, 18 hypertrophic obstructive cardiomyopathy (HOCM) and 14 non-obstructive HCM (HNCM) patients underwent 4D flow MRI. We investigated TKE value calculated by 4D flow MRI, echocardiographic findings; left ventricular pressure gradient (LVPG), mitral regurgitation (MR) and clinical symptom.

Results

HOCM was defined by the 30 mmHg or greater of LVPG (HOCM: 87.7±47.3 mmHg, HNCM; 5.8±7.8 mmHg, p<0.001). TKE value in HOCM patients was significantly higher than HNCM (14.2±4.7 mJ vs. 9.0±4.6 mJ, p<0.001). There was a significant positive linear relationship between TKE value and LVPG (r=0.488, p=0.046). There was no significant relationship between NYHA functional class and TKE value (p=0.47) or LVPG (p=0.11). ROC curve analysis showed that optimal cut off point of TKE value between HOCM and HNCM (sensitivity=95%, specificity=62%, AUC=0.798) was 9.270 mJ. Multiple linear regression showed that there was significant association between severity of MR and combination of TKE (p=0.015) or LVPG (p–=0.012). A representative case demonstrated the significant reduction of TKE value 1 week and 3 months after alcohol septal reduction compared with that obtained before the procedure (Figure)

Conclusion

Our findings suggest that 4D Flow MRI can effectively evaluate the energy dissipation associated with LV outflow tract obstruction and TKE value is useful for identifying HOCM. TKE value also can be the novel parameter of the severity of HOCM.

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.

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.

Phosphorylation of BACH1 switches its function from transcription factor to mitotic chromosome regulator and promotes its interaction with HMMR

The transcription repressor BACH1 performs mutually independent dual roles in transcription regulation and chromosome alignment during mitosis by supporting polar ejection force of mitotic spindle. We now found that the mitotic spindles became oblique relative to the adhesion surface following endogenous BACH1 depletion in HeLa cells. This spindle orientation rearrangement was rescued by re-expression of BACH1 depending on its interactions with HMMR and CRM1, both of which are required for the positioning of mitotic spindle, but independently of its DNA-binding activity. A mass spectrometry analysis of BACH1 complexes in interphase and M phase revealed that BACH1 lost during mitosis interactions with proteins involved in chromatin and gene expression but retained interactions with HMMR and its known partners including CHICA. By analyzing BACH1 modification using stable isotope labeling with amino acids in cell culture, mitosis-specific phosphorylations of BACH1 were observed, and mutations of these residues abolished the activity of BACH1 to restore mitotic spindle orientation in knockdown cells and to interact with HMMR. Detailed histological analysis of Bach1-deficient mice revealed lengthening of the epithelial fold structures of the intestine. These observations suggest that BACH1 performs stabilization of mitotic spindle orientation together with HMMR and CRM1 in mitosis, and that the cell cycle-specific phosphorylation switches the transcriptional and mitotic functions of BACH1.

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.

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 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

Novel retinoblastoma mutation abrogating the interaction to E2F2/3, but not E2F1, led to selective suppression of thyroid tumors

Mutant mouse models are indispensable tools for clarifying gene functions and elucidating the pathogenic mechanisms of human diseases. Here, we describe novel cancer models bearing point mutations in the retinoblastoma gene (Rb1) generated by N-ethyl-N-nitrosourea mutagenesis. Two mutations in splice sites reduced Rb1 expression and led to a tumor spectrum and incidence similar to those observed in the conventional Rb1 knockout mice. The missense mutant, Rb1^D326V/+, developed pituitary tumors, but thyroid tumors were completely suppressed. Immunohistochemical analyses of thyroid tissue revealed that E2F1, but not E2F2/3, was selectively inactivated, indicating that the mutant Rb protein (pRb) suppressed thyroid tumors by inactivating E2F1. Interestingly, Rb1^D326V/+ mice developed pituitary tumors that originated from the intermediate lobe of the pituitary, despite selective inactivation of E2F1. Furthermore, in the anterior lobe of the pituitary, other E2F were also inactivated. These observations show that pRb mediates the inactivation of E2F function and its contribution to tumorigenesis is highly dependent on the cell type. Last, by using a reconstitution assay of synthesized proteins, we showed that the D326V missense pRb bound to E2F1 but failed to interact with E2F2/3. These results reveal the effect of the pRb N-terminal domain on E2F function and the impact of the protein on tumorigenesis. Thus, this mutant mouse model can be used to investigate human Rb family-bearing mutations at the N-terminal region.

Japanese strategies to maximize heart and lung availabilities: experience from 100 consecutive brain-dead donors

OBJECTIVE

Because the donor shortage is extremely severe in Japan because of a strict organ transplantation law, special strategies have been established to maximize heart and lung transplantations (HTs and LTs, respectively). We reviewed 100 consecutive brain-dead donors to evaluate our strategies to identify and manage heart and lung donors.

METHODS

We retrospectively reviewed all 100 consecutive brain-dead donors procured since the law was issued in 1997. There were 56 mens and the overall mean donor age was 43.5 years. The causes of death were cerebrovascular disease (n = 62), head trauma (n = 20), and asphyxia (n = 16): Since November 2002, special transplant management doctors were sent to donor hospitals to assess cardiac and lung functions, seeking to identify transplant opportunities. They stabilized donor hemodynamics and lung function by administering antidiuretic hormone intravenously and performing bronchofibroscopy for pulmonary toilet.

RESULTS

Seventy-nine HTs, 1 heart-lung transplantations, and 78 LTs (46 single and 32 bilateral) were performed. By applying these strategies organs per donor were increased from 4.5 to 6.8. Among heart donors, 61/80 were marginal: high inotrope requirement (n = 29), cardiopulmonary resuscitation (n = 28), and/or >55 years old (n = 20). None of the 80 HT recipients died of primary graft failure (PGF). Patient survival rate at 10 years after HT was 95.4%. Among lung donors, 48/65 were marginal: pneumonia (n = 41), chest trauma (n = 4), and >55 years old (n = 9). Only 2/78 LT recipients died of PGF. Patient survival rate at 3 years after LT was 72.2%. After inducing frequent pulmonary toilet, lung procurement and patient survival rates increased significantly after LT.

CONCLUSIONS

Although the number of cases was still small, the availability of organs has been greater and the outcomes of HT/LT acceptable.

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.