TM4SF1-AS1 inhibits apoptosis by promoting stress granule formation in cancer cells.

Long noncoding RNAs (lncRNAs) play pivotal roles in tumor development. To identify dysregulated lncRNAs in gastric cancer (GC), we analyzed genome-wide trimethylation of histone H3 lysine 4 (H3K4me3) to screen for transcriptionally active lncRNA genes in the non-tumorous gastric mucosa of patients with GC and healthy individuals. We found that H3K4me3 at TM4SF1-AS1 was specifically upregulated in GC patients and that the expression of TM4SF1-AS1 was significantly elevated in primary and cultured GC cells. TM4SF1-AS1 contributes to GC cell growth in vitro and in vivo, and its oncogenic function is mediated, at least in part, through interactions with purine-rich element-binding protein α (Pur-α) and Y-box binding protein 1 (YB-1). TM4SF1-AS1 also activates interferon signaling in GC cells, which is dependent on Pur-α and RIG-I. Chromatin isolation by RNA purification (ChIRP)-mass spectrometry demonstrated that TM4SF1-AS1 was associated with several stress granule (SG)-related proteins, including G3BP2, RACK1, and DDX3. Notably, TM4SF1-AS1 promoted SG formation and inhibited apoptosis in GC cells by sequestering RACK1, an activator of the stress-responsive MAPK pathway, within SGs. TM4SF1-AS1-induced SG formation and apoptosis inhibition are dependent on Pur-α and YB-1. These findings suggested that TM4SF1-AS1 contributes to tumorigenesis by enhancing SG-mediated stress adaptation.

Red blood cell distribution width as a novel marker for predicting bleeding after endoscopic resection for early gastric cancer.

Objectives: Endoscopic resection (ER) is a minimally invasive treatment for early gastric cancer (EGC); however, there is a high occurrence of bleeding. This study aimed to clarify the significance of red blood cell distribution width (RDW) as a predictive risk factor for bleeding after ER for EGC. Methods: We conducted a retrospective study based on data for patients who underwent ER for EGC from 2019 to 2021. This study included 79 lesions in 54 patients who underwent ER for EGC. The primary outcome was the association between RDW before ER and bleeding within 28 days of treatment. Receiver operating characteristic (ROC) curves were constructed, wherein areas under the curve (AUCs) and 95% confidence intervals were calculated to compare the discriminatory power of RDW for predicting bleeding. Results: Endoscopic submucosal dissection was used as the resection method for 73 lesions, whereas endoscopic mucosal resection was used for six lesions. En bloc resection was performed in all cases. There were no cases of perforation; however, bleeding after ER occurred in five cases (9.3%). ROC curve analysis of bleeding after ER showed that the AUC was 0.843 with a good diagnostic performance. When the cut-off value of RDW was set at 14.4%, sensitivity and specificity were 80% and 85.7%, respectively. There was a bleeding rate of 36.4% (4/11) at an RDW of ≥14.4%, which was significantly higher than that of 2.3% (1/43) at an RDW of <14.4%. Conclusion: RDW can be a predictor of bleeding risk after ER for EGC.

Serum amyloid A1 recruits neutrophils to the invasive front of T1 colorectal cancers.

BACKGROUND AND AIM: The tumor microenvironment plays an essential role in the development and progression of colorectal cancer (CRC). We recently reported that crosstalk between CRC cells and tumor-associated macrophages (TAMs) via serum amyloid A1 (SAA1) promotes invasion by T1 CRCs. In the present study, we aimed to clarify the role of neutrophils in early CRCs. METHODS: Immunohistochemical analysis of CD66b, chemokine CXC motif ligand 8 (CXCL8 or interleukin-8, IL-8) and matrix metalloproteinase-9 (MMP-9) was performed using primary T1 CRCs (n = 49). The HL-60 human promyelocytic leukemia cell line and THP-1 human monocytic leukemia cell line were used to obtain neutrophil-like and macrophage-like cells, respectively. Boyden chamber assays were used to analyze cell migration and invasion, and quantitative RT-PCR was used to analyze gene expression. RESULTS: Immunohistochemical analysis revealed accumulation of neutrophils at the SAA1-positive invasive front of T1 CRCs. Experiments using HL-60 cells suggested that treatment with SAA1 induced neutrophil migration and expression of CXCL8 and MMP-9 in neutrophils and that neutrophils promote CRC cell migration and invasion. Immunohistochemistry confirmed accumulation of CXCL8- or MMP-9-positive neutrophils at the SAA1-positive invasive front of T1 CRCs. Moreover, co-culture experiments using CRC, THP-1 and HL-60 cells suggested that CRC cells activated by macrophages upregulate CXCL8 and MMP-9 in neutrophils. CONCLUSIONS: Our results suggest that interplay between macrophages and CRC cells leads to recruitment of neutrophils to the invasive front of T1 CRCs and that SAA1 secreted by CRC cells activate neutrophils to promote invasion.

Pyogenic spondylitis following endoscopic submucosal dissection for early gastric cancer.

A man in his 80s who had a history of diabetes mellitus and aortic valve replacement was referred to our hospital for treatment of early gastric cancer and underwent endoscopic submucosal dissection (ESD). Three days after ESD, the patient presented with low back pain and fever (38.7°). We initially considered adverse events associated with gastric ESD such as delayed perforation. Moreover, thromboembolism and infectious endocarditis were suspected because of his medical history. However, there were no remarkable findings suggestive of these diseases. Finally, based on the results of blood cultures and MRI, the diagnosis of pyogenic spondylitis (PS) was made. We administered antibiotics for 12 weeks, and the patient improved without neurological impairments. This case indicates that bacteraemia and subsequent PS can occur following gastric ESD. Physicians should not overlook the patient's physical signs related to various adverse events after ESD.

Direct clipping using underwater inversion method for colonic diverticular bleeding.

Video 1Endoscopic direct clipping using an underwater inversion method for diverticular bleeding in the descending colon.

Traction-assisted endoscopic submucosal dissection for a previously tattooed colonic laterally spreading tumor.

Video 1Traction-assisted colorectal endoscopic submucosal dissection using the multiloop method for a previously tattooed laterally spreading tumor in the sigmoid colon.

Activated macrophages promote invasion by early colorectal cancer via an interleukin 1ß-serum amyloid A1 axis.

Submucosal invasion and lymph node metastasis are important issues affecting treatment options for early colorectal cancer (CRC). In this study, we aimed to unravel the molecular mechanism underlying the invasiveness of early CRCs. We performed RNA-sequencing (RNA-seq) with poorly differentiated components (PORs) and their normal counterparts isolated from T1 CRC tissues and detected significant upregulation of serum amyloid A1 (SAA1) in PORs. Immunohistochemical analysis revealed that SAA1 was specifically expressed in PORs at the invasive front of T1b CRCs. Upregulation of SAA1 in CRC cells promoted cell migration and invasion. Coculture experiments using CRC cell lines and THP-1 cells suggested that interleukin 1ß (IL-1ß) produced by macrophages induces SAA1 expression in CRC cells. Induction of SAA1 and promotion of CRC cell migration and invasion by macrophages were inhibited by blocking IL-1ß. These findings were supported by immunohistochemical analysis of primary T1 CRCs showing accumulation of M1-like/M2-like macrophages at SAA1-positive invasive front regions. Moreover, SAA1 produced by CRC cells stimulated upregulation of matrix metalloproteinase-9 in macrophages. Our data suggest that tumor-associated macrophages at the invasive front of early CRCs promote cancer cell migration and invasion through induction of SAA1 and that SAA1 may be a predictive biomarker and a useful therapeutic target.

An Integrated Epigenome and Transcriptome Analysis to Clarify the Effect of Epigenetic Inhibitors on GIST.

BACKGROUND/AIM: Epigenetic alterations play an important role in the pathogenesis of gastrointestinal stromal tumors (GISTs). To obtain further insight into the GIST epigenome, we analyzed genome-wide histone modification and DNA methylation in GIST cells. MATERIALS AND METHODS: To reverse epigenetic silencing, GIST-T1 cells were treated with a DNA methyltransferase inhibitor and a histone deacetylase inhibitor, and subsequently H3K4me3 levels, the DNA methylome, and the transcriptome were analyzed. RESULTS: Treatment with epigenetic inhibitors not only up-regulated genes with DNA methylation, but also genes related to interferon signaling. ChIP-seq analysis revealed that drug treatment up-regulated H3K4me3 levels in retrotransposons, including endogenous retroviruses (ERV). Finally, utilizing the omics data, we found that hypermethylation of MEG3 is a frequent event and an indicator of poorer prognosis in GIST patients. CONCLUSION: Epigenetic inhibitors may activate interferon signaling via viral mimicry in GIST cells. Moreover, epigenome data could be a useful resource to identify novel GIST-related genes.

Autoimmune gastritis concomitant with gastric adenoma and subacute combined degeneration of the spinal cord.

A 62-year-old woman was referred to our department for further investigation of anaemia. Blood test showed macrocytic anaemia. Oesophagogastroduodenoscopy (OGD) revealed proximal-predominant gastric atrophy and flat elevated lesion in the gastric body. Several days after OGD, she complained of gait disturbance and was diagnosed with subacute combined degeneration of the spinal cord. Furthermore, laboratory tests showed positive for both anti-parietal cell and anti-intrinsic factor antibodies, as well as increased serum gastrin level and decreased pepsinogen I level, which confirmed the diagnosis of autoimmune gastritis (AIG). Anaemia and neurological symptoms were improved after vitamin B12 supplementation. Subsequently, the patient underwent gastric endoscopic submucosal dissection; histopathological examination revealed gastric adenoma. AIG can cause gastric neoplasms and vitamin B12 deficiency, with the latter resulting in pernicious anaemia and neurological disorders. These diseases are treatable but potentially life-threatening. This case highlights the importance of early diagnosis of AIG and proper management of its comorbidities.

Dual EZH2 and G9a inhibition suppresses multiple myeloma cell proliferation by regulating the interferon signal and IRF4-MYC axis.

Epigenetic mechanisms such as histone modification play key roles in the pathogenesis of multiple myeloma (MM). We previously showed that EZH2, a histone H3 lysine 27 (H3K27) methyltransferase, and G9, a H3K9 methyltransferase, are potential therapeutic targets in MM. Moreover, recent studies suggest EZH2 and G9a cooperate to regulate gene expression. We therefore evaluated the antitumor effect of dual EZH2 and G9a inhibition in MM. A combination of an EZH2 inhibitor and a G9a inhibitor strongly suppressed MM cell proliferation in vitro by inducing cell cycle arrest and apoptosis. Dual EZH2/G9a inhibition also suppressed xenograft formation by MM cells in vivo. In datasets from the Gene Expression Omnibus, higher EZH2 and EHMT2 (encoding G9a) expression was significantly associated with poorer prognoses in MM patients. Microarray analysis revealed that EZH2/G9a inhibition significantly upregulated interferon (IFN)-stimulated genes and suppressed IRF4-MYC axis genes in MM cells. Notably, dual EZH2/G9a inhibition reduced H3K27/H3K9 methylation levels in MM cells and increased expression of endogenous retrovirus (ERV) genes, which suggests that activation of ERV genes may induce the IFN response. These results suggest that dual targeting of EZH2 and G9a may be an effective therapeutic strategy for MM.

Haemorrhagic exfoliative oesophagitis associated with nasogastric tube placement.

A 92-year-old man hospitalised for cerebral infarction developed haematemesis. The patient was taking low-dose aspirin and apixaban for his cerebral infarction and non-valvular atrial fibrillation. His enteral nutrition was administrated through nasogastric tube. Upper endoscopy revealed active bleeding from a protruded lesion in the upper oesophagus. The lesion was removed by washing with a water jet, followed by successful endoscopic haemostasis. Histopathological examination revealed degenerated squamous epithelium without specific findings; the diagnosis was exfoliative oesophagitis. In our case, mechanical mucosal injury caused by nasogastric tube placement may result in exfoliative oesophagitis. In addition, the use of low-dose aspirin with apixaban may have contributed to the bleeding. We then performed a wire-guided nasogastric tube placement under fluoroscopy. No further bleeding was observed, but the patient died of sepsis 1 month later. This case highlights the importance of a risk assessment and management of oesophageal complications associated with nasogastric tube placement.

Comparison of dissection speed during colorectal ESD between the novel Multiloop (M-loop) traction method and ESD methods without traction.

Background and study aims We previously reported on a novel traction method called Multiloop (M-loop) for faster colorectal endoscopic submucosal dissection (ESD). In this study, we retrospectively compared the difference in submucosal dissection time (SDT), and submucosal dissection speed (SDS) between groups of patients who were treated using traction with the M-loop method, and with non-traction methods of colorectal ESD. Patients and methods We reviewed and timed duration of colorectal ESD by the non-traction method from videos recorded between June 2016 and December 2017. From January 2018 onward, we used the M-loop method during all colorectal ESDs and timed it until August 2018. Outcomes of colorectal ESD with the M-loop method and non-traction methods were compared. The study involved two experts and eight non-experts and was carried out at a tertiary endoscopic center in Japan. Results The study included 50 patients who treated with the M-loop method and 115 patients treated with the non-traction method. Submucosal dissection time (SDT) was not significantly different (M-loop group, 42.1  ±â€Šâ€Š4.2 min, non-traction ESD group, 51.9 ±â€Š3.3 min) ( P  = 0.098), but submucosal dissection speed (SDS) was significantly greater (M-loop group, 28.0 ±â€Š2.9 mm 2  /min, non-traction ESD group, 19.9 ±â€Š2.0 mm 2 /min) ( P  = 0.0014) in the M-loop method group. Multivariate analysis showed that the M-loop method increased SDS by odds ratio of 1.46 ( P  = 0.001) when compared to the non-traction ESD method. A significant difference was also observed for SDT and SDS when the two methods were compared after propensity score matching ( P  = 0.001). No differences in unfavorable outcomes were observed. Conclusions The M-loop method improved SDS compared to non-traction methods of ESD. The method is an effective tool to assist colorectal ESD.

Upregulation of adipocyte enhancer-binding protein 1 in endothelial cells promotes tumor angiogenesis in colorectal cancer.

Tumor angiogenesis is an important therapeutic target in colorectal cancer (CRC). We aimed to identify novel genes associated with angiogenesis in CRC. Using RNA sequencing analysis in normal and tumor endothelial cells (TECs) isolated from primary CRC tissues, we detected frequent upregulation of adipocyte enhancer-binding protein 1 (AEBP1) in TECs. Immunohistochemical analysis revealed that AEBP1 is upregulated in TECs and stromal cells in CRC tissues. Quantitative RT-PCR analysis showed that there is little or no AEBP1 expression in CRC cell lines, but that AEBP1 is well expressed in vascular endothelial cells. Levels of AEBP1 expression in Human umbilical vein endothelial cells (HUVECs) were upregulated by tumor conditioned medium derived from CRC cells or by direct coculture with CRC cells. Knockdown of AEBP1 suppressed proliferation, migration, and in vitro tube formation by HUVECs. In xenograft experiments, AEBP1 knockdown suppressed tumorigenesis and microvessel formation. Depletion of AEBP1 in HUVECs downregulated a series of genes associated with angiogenesis or endothelial function, including aquaporin 1 (AQP1) and periostin (POSTN), suggesting that AEBP1 might promote angiogenesis through regulation of those genes. These results suggest that upregulation of AEBP1 contributes to tumor angiogenesis in CRC, which makes AEBP1 a potentially useful therapeutic target.

Multiloop as a novel traction method in accelerating colorectal endoscopic submucosal dissection.

BACKGROUND AND AIMS: Traction methods have been reported to speed up endoscopic submucosal dissection (ESD). We used the multiloop (M-loop) method as a traction method for colorectal ESD and recorded the submucosal dissection time (SDT) and submucosal dissection speed (SDS). METHODS: From January to August 2018, we used the M-loop method for colorectal ESD procedures and timed the duration and recorded the outcomes. Two experts and eight nonexperts performed the procedures, which were carried out at a tertiary endoscopic center in Japan. RESULTS: A total of 50 patients were treated by colorectal ESD using the M-loop method. The mean SDT was 42.1 ± 4.16 minutes and the mean SDS was 28.0 ± 2.89 mm2/minutes. The mean SDS was 38.9 ± 6.9 mm2/minutes for experts and 25.3 ± 3.1 mm2/minutes for nonexperts. En bloc resection was achieved in 100% of cases. There were 3 adverse events and unfavorable outcomes. CONCLUSIONS: Traction by the M-loop method improved SDS in colorectal ESD. The method can be an effective tool to assist colorectal ESD. Further evaluation of the usefulness of the M-loop method is required in direct comparison with conventional ESD.