Downregulation of SMOC1 is associated with progression of colorectal traditional serrated adenomas

BACKGROUND

Aberrant DNA methylation is prevalent in colorectal serrated lesions. We previously reported that the CpG island of SMOC1 is frequently methylated in traditional serrated adenomas (TSAs) and colorectal cancers (CRCs) but is rarely methylated in sessile serrated lesions (SSLs). In the present study, we aimed to further characterize the expression of SMOC1 in early colorectal lesions.

METHODS

SMOC1 expression was analyzed immunohistochemically in a series of colorectal tumors (n = 199) and adjacent normal colonic tissues (n = 112).

RESULTS

SMOC1 was abundantly expressed in normal colon and SSLs while it was significantly downregulated in TSAs, advanced adenomas and cancers. Mean immunohistochemistry scores were as follows: normal colon, 24.2; hyperplastic polyp (HP), 18.9; SSL, 23.8; SSL with dysplasia (SSLD)/SSL with early invasive cancer (EIC), 15.8; TSA, 5.4; TSA with high grade dysplasia (HGD)/EIC, 4.7; non-advanced adenoma, 21.4; advanced adenoma, 11.9; EIC, 10.9. Higher levels SMOC1 expression correlated positively with proximal colon locations and flat tumoral morphology, reflecting its abundant expression in SSLs. Among TSAs that contained both flat and protruding components, levels of SMOC1 expression were significantly lower in the protruding components.

CONCLUSION

Our results suggest that reduced expression of SMOC1 is associated with progression of TSAs and conventional adenomas and that SMOC1 expression may be a biomarker for diagnosis of serrated lesions and risk prediction in colorectal tumors.

ACLP Activates Cancer-Associated Fibroblasts and Inhibits CD8+ T-Cell Infiltration in Oral Squamous Cell Carcinoma

We previously showed that upregulation of adipocyte enhancer-binding protein 1 (AEBP1) in vascular endothelial cells promotes tumor angiogenesis. In the present study, we aimed to clarify the role of stromal AEBP1/ACLP expression in oral squamous cell carcinoma (OSCC). Immunohistochemical analysis showed that ACLP is abundantly expressed in cancer-associated fibroblasts (CAFs) in primary OSCC tissues and that upregulated expression of ACLP is associated with disease progression. Analysis using CAFs obtained from surgically resected OSCCs showed that the expression of AEBP1/ACLP in CAFs is upregulated by co-culture with OSCC cells or treatment with TGF-β1, suggesting cancer-cell-derived TGF-β1 induces AEBP1/ACLP in CAFs. Collagen gel contraction assays showed that ACLP contributes to the activation of CAFs. In addition, CAF-derived ACLP promotes migration, invasion, and in vivo tumor formation by OSCC cells. Notably, tumor stromal ACLP expression correlated positively with collagen expression and correlated inversely with CD8+ T cell infiltration into primary OSCC tumors. Boyden chamber assays suggested that ACLP in CAFs may attenuate CD8+ T cell migration. Our results suggest that stromal ACLP contributes to the development of OSCCs, and that ACLP is a potential therapeutic target.

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.

Vancouver call for action to strengthen expertise in radiological protection worldwide

Ionising radiation has been used for over a century for peaceful purposes, revolutionising health care and promoting well-being through its application in industry, science, and medicine. For almost as long, the International Commission on Radiological Protection (ICRP) has promoted understanding of health and environmental risks of ionising radiation and developed a protection system that enables the safe use of ionising radiation in justified and beneficial practices, providing protection from all sources of radiation. However, we are concerned that a shortage of investment in training, education, research, and infrastructure seen in many sectors and countries may compromise society's ability to properly manage radiation risks, leading to unjustified exposure to or unwarranted fear of radiation, impacting the physical, mental, and social well-being of our peoples. This could unduly limit the potential for research and development in new radiation technologies (healthcare, energy, and the environment) for beneficial purposes. ICRP therefore calls for action to strengthen expertise in radiological protection worldwide through: (1) National governments and funding agencies strengthening resources for radiological protection research allocated by governments and international organisations, (2) National research laboratories and other institutions launching and sustaining long-term research programmes, (3) Universities developing undergraduate and graduate university programmes and making students aware of job opportunities in radiation-related fields, (4) Using plain language when interacting with the public and decision makers about radiological protection, and (5) Fostering general awareness of proper uses of radiation and radiological protection through education and training of information multipliers. The draft call was discussed with international organisations in formal relations with ICRP in October 2022 at the European Radiation Protection Week in Estoril, Portugal, and the final call announced at the 6th International Symposium on the System of Radiological Protection of ICRP in November 2022 in Vancouver, Canada.

CXCL12 is expressed by skeletal muscle cells in tongue oral squamous cell carcinoma

BACKGROUND

The CXCL12/CXCR4 axis plays a pivotal role in the progression of various malignancies, including oral squamous cell carcinoma (OSCC). In this study, we aimed to clarify the biological and clinical significance of CXCL12 in the tumor microenvironment of OSCCs.

METHODS

Publicly available single-cell RNA-sequencing (RNA-seq) datasets were used to analyze CXCL12 expression in head and neck squamous cell carcinomas (HNSCC). Immunohistochemical analysis of CXCL12, α-smooth muscle antigen (α-SMA), fibroblast activation protein (FAP) and CD8 was performed in a series of 47 surgically resected primary tongue OSCCs. Human skeletal muscle cells were co-cultured with or without OSCC cells, after which CXCL12 expression was analyzed using quantitative reverse-transcription PCR.

RESULTS

Analysis of the RNA-seq data suggested CXCL12 is abundantly expressed in stromal cells within HNSCC tissue. Immunohistochemical analysis showed that in grade 1 primary OSCCs, CXCL12 is expressed in both tumor cells and muscle cells. By contrast, grade 3 tumors were characterized by disruption of muscle structure and reduced CXCL12 expression. Quantitative analysis of CXCL12-positive areas within tumors revealed that reduced CXCL12 expression correlated with poorer overall survival. Levels of CXCL12 expression tended to inversely correlate α-SMA expression and positively correlate with infiltration by CD8+ lymphocytes, though these relations did not reach statistical significance. CXCL12 was significantly upregulated in muscle cells co-cultured with OSCC cells.

CONCLUSION

Our results suggest that tongue OSCC cells activate CXCL12 expression in muscle cells, which may contribute to tumor progression. However, CXCL12 is reduced in advanced OSCCs due to muscle tissue destruction.

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.

Survival and renal outcomes of direct heart transplant from veno-arterial extracorporeal membrane oxygenation support

Backgrounds

Patients on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support are given the highest priority for cardiac transplantation (OHT) in the new UNOS heart allocation policy adopted in October 2018. Although patients may receive an organ quicker there may not be enough time to recover end-organ function. To date, little is known about survival and renal outcomes of direct OHT in patients that have been supported with VA-ECMO as a bridge to transplant due to limited experience in most transplant centers.

Purpose

The aim of this study was to investigate survival and renal outcomes of direct OHT in patients supported with VA-ECMO prior to transplant.

Methods

From January 2010 to February 2022, 23 patients who received single organ OHT alone directly from VA-ECMO support were retrospectively analyzed (16 patients after the new allocation policy). Kaplan-Meier analysis was used to estimate event-free survival.

Results

The median age of recipients was 48 years. The median length of pre-transplant VA-ECMO support was 5 days. Additional pre-transplant support with intra-aortic balloon pump or Impella was utilized in 15 patients (65.2%) and 2 patients (9%) respectively. There was a trend toward improvement of serum creatinine after initiation of VA-ECMO support (Pre-ECMO: 1.66±1.22 mg/dl vs. Pre-OHT: 1.20±0.74 mg/dl, P=0.084). Four patients required preoperative renal replacement therapy (RRT); three were on RRT at the time of OHT. The median ischemic time of donor hearts was 168 minutes. VA-ECMO support was continued in 10 patients (43.5%) after OHT.

Hospital mortality was 8.7% (2 patients). Post-transplant RRT was required in 9 patients (39.1%), and, of these, 5 patients were transitioned to permanent dialysis. Among the 14 patients who did not require post-transplant RRT, none required RRT during the follow-up period (median, 21.5 months). Kaplan-Meier survival analysis showed that estimated survival at 1 year and 3 years were 86.1%, and 77.5%, respectively (Figure 1A). The freedom from dialysis rate was 82.4% at 1 year, and 74.9% at 3 years (Figure 2A). Both survival (100% vs. 66.7%, P=0.008, Fig.1B) and dialysis free rate (100% vs. 55.6%, P=0.002, Figure 2B) at one-year were significantly worse in patients who required postoperative RRT.

Conclusions

To our knowledge this is the largest single center study of OHT in patients that were supported with VA-ECMO. VA-ECMO as a bridge to end-organ recovery and OHT resulted in excellent outcomes. Patients who required post-transplant RRT more likely to require long-term dialysis, while those that did not receive RRT showed favorable outcomes. Overall survival in this patient population is comparable to patients that were not on VA-ECMO prior to transplant.

Funding Acknowledgement

Type of funding sources: None.

Summary of the 2021 ICRP workshop on the future of radiological protection

The International Commission on Radiological Protection (ICRP) has embarked on a process to review and revise the current System of Radiological Protection ('the System'). To stimulate discussion, the ICRP published two open-access articles: one on aspects of the System that might require review, and another on research that might improve the scientific foundation of the System. Building on these articles, the ICRP organized a Workshop on the Future of Radiological Protection as an opportunity to engage in the review and revision of the System. This digital workshop took place from 14 October-3 November 2021 and included 20 live-streamed and 43 on-demand presentations. Approximately 1500 individuals from 100 countries participated. Based on the subjects covered by the presentations, this summary is organized into four broad areas: the scientific basis, concepts and application of the System; and the role of the ICRP. Some of the key topics that emerged included the following: classification of radiation-induced effects; adverse outcome pathway methodologies; better understanding of the dose-response relationship; holistic and reasonable approaches to optimization of protection; radiological protection of the environment; ethical basis of the System; clarity, consistency and communication of the System; application of the System in medicine and application of the principles of justification and optimization of protection.

Keeping the ICRP recommendations fit for purpose

The International Commission on Radiological Protection (ICRP) has embarked on a review and revision of the system of Radiological Protection that will update the 2007 general recommendations in ICRPPublication 103. This is the beginning of a process that will take several years, involving open and transparent engagement with organisations and individuals around the world. While the system is robust and has performed well, it must adapt to address changes in science and society to remain fit for purpose. The aim of this paper is to encourage discussions on which areas of the system might gain the greatest benefit from review, and to initiate collaborative efforts. Increased clarity and consistency are high priorities. The better the system is understood, the more effectively it can be applied, resulting in improved protection and increased harmonisation. Many areas are identified for potential review including: classification of effects, with particular focus on tissue reactions; reformulation of detriment, potentially including non-cancer diseases; re-evaluation of the relationship between detriment and effective dose, and the possibility of defining detriments for males and females of different ages; individual variation in the response to radiation exposure; heritable effects; and effects and risks in non-human biota and ecosystems. Some of the basic concepts are also being considered, including the framework for bringing together protection of people and the environment, incremental improvements to the fundamental principles of justification and optimisation, a broader approach to protection of individuals, and clarification of the exposure situations introduced in 2007. In addition, ICRP is considering identifying where explicit incorporation of the ethical basis of the system would be beneficial, how to better reflect the importance of communications and stakeholder involvement, and further advice on education and training. ICRP invites responses on these and other areas relating to the review of the System of Radiological Protection.

DLEU1 promotes oral squamous cell carcinoma progression by activating interferon-stimulated genes

Long noncoding RNAs (lncRNAs) are deeply involved in cancer development. We previously reported that DLEU1 (deleted in lymphocytic leukemia 1) is one of the lncRNAs overexpressed in oral squamous cell carcinoma (OSCC) cells, where it exhibits oncogenic activity. In the present study, we further clarified the molecular function of DLEU1 in the pathogenesis of OSCC. Chromatin immunoprecipitation-sequencing (ChIP-seq) analysis revealed that DLEU1 knockdown induced significant changes in the levels of histone H3 lysine 4 trimethylation (H3K4me3) and H3K27 acetylation (H3K27ac) in OSCC cells. Notably, DLEU1 knockdown suppressed levels of H3K4me3/ H3K27ac and expression of a number of interferon-stimulated genes (ISGs), including IFIT1, IFI6 and OAS1, while ectopic DLEU1 expression activated these genes. Western blot analysis and reporter assays suggested that DLEU1 upregulates ISGs through activation of JAK-STAT signaling in OSCC cells. Moreover, IFITM1, one of the ISGs induced by DLUE1, was frequently overexpressed in primary OSCC tumors, and its knockdown inhibited OSCC cell proliferation, migration and invasion. These findings suggest that DLEU1 exerts its oncogenic effects, at least in part, through activation of a series ISGs in OSCC cells.

Activated macrophages promote invasion by early colorectal cancer via an interleukin 1β-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 1β (IL‐1β) 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‐1β. 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.

ICRP recommendations for recovery

In 2020, the International Commission on Radiological Protection (ICRP) issued Publication 146 which provides a framework of the radiological protection of people and the environment in the case of a large nuclear accident. Mitigation of radiological consequences is achieved using the fundamental principles of justification of decisions and optimisation of protection. These recommendations emphasise the importance of the optimisation of protection for the rehabilitation of living and working conditions in the affected areas during the intermediate and long-term phases. They underline the role of co-operation between the authorities, experts, and the affected population in the co-expertise process to facilitate informed decisions about their own protection. ICRP defines reference levels to be selected within generic bands of exposure considering the induced risk of radiation, as well as the feasibility of controlling the situation.

Diffuse large B-cell lymphoma of the gallbladder arised 8 years after malignant lymphoma of the right testis: A case report and literature review

•

Gallbladder involvement by lymphoma is extremely rare, and only 68 cases have been reported in the English literature so far.

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We experienced a case of diffuse large B-cell lymphoma (DLBCL) of the gallbladder arising 8 years after DLBCL of the right testis.

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We compiled and analysed reported cases in terms of background, symptoms, imaging findings, and prognosis.

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DLBCL was significantly more involved in other organs simultaneously or heterochronously in contrast of MALT lymphoma (p = 0.004).

•

Gallbladder lymphoma should be added to the differential diagnosis of gallbladder tumours.

Introduction

Gallbladder involvement in lymphoma is extremely rare, and only 68 cases have been reported in the English literature so far. We experienced a case of diffuse large B-cell lymphoma (DLBCL) of the gallbladder arising 8 years after DLBCL of the right testis.

Presentation of case

A 68-year-old man underwent orchiectomy for malignant lymphoma of the right testis pathologically diagnosed as DLBCL 8 years ago. Systemic surveillance incidentally revealed a gallbladder tumour, and elective resection of the gallbladder bed of the liver was performed under a preoperative diagnosis of gallbladder cancer. The histopathological examination revealed DLBCL. At re-evaluation 3 months after surgery, he was diagnosed as having DLBCL involving the stomach. There had been no recurrence for 39 months after chemotherapy and radiation, but he suffered from a poor general condition due to protein-losing enteropathy and died of infection.

Discussion

We compiled and analysed reported cases of malignant lymphomas involving the gallbladder in terms of background, symptoms, imaging findings, and prognosis. Compared to MALT lymphoma, DLBCL was significantly more involved in other organs simultaneously or heterochronously (p = 0.004).

Conclusion

Gallbladder lymphoma should be added to the differential diagnosis of gallbladder tumours, especially when clinical findings are not consistent with the typical course of gallbladder carcinoma and cholecystitis.

Computed tomography of the head and the risk of brain tumours during childhood and adolescence: results from a case-control study in Japan

To clarify whether medical radiation exposure, especially from head computed tomography (CT), increases the risk of brain tumours in young patients in Japan, which ranks the second highest in the world in the number of paediatric CT examinations following the US. From 2011 to 2015, we performed a case-control study of 120 brain tumour patients and 360 appendicitis patients as controls. Reasons, the number of brain and head CT scans date were available from interviews. A cumulative radiation dose to the brain was calculated as a sum of doses received from head CT scans and from conventional X-rays and estimated using a reference table derived from a literature review of published studies. We performed conditional logistic regression to assess the risk of brain tumours from brain and head CT, and from conventional head X-ray procedures. The case group received on average 1.8 CTs to the brain area and 2.2 CTs to the whole head, with a mean estimated brain dose of 32 ±13 mGy. The odds ratio for developing a brain tumour from having a brain CT was 0.93 (95% confidence interval: 0.38-1.82). This was hardly altered when adjusting for parental educational history and for other diseases (history of neurological disease and attention-deficit disorder/attention-deficit hyperactivity disorder). Neither whole head CT nor cumulative brain dose to the brain increased the risk of glioma or of all brain tumours. Although this study conducted in Japan, where ranks second in the number of CT scans conducted in the world, did not show an increased risk of brain tumours related to CT scans, it should be taken with caution due to a case-control study with limited sample size.

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.

Two cases of bile duct carcinoma patients who underwent the photodynamic therapy using talaporfin sodium (Laserphyrin®)

The efficacy of adjuvant photodynamic therapy (PDT) using the new photosensitizer, talaporfin sodium (TPS) has been clinically examined in some patients with bile duct carcinoma (BDC). Based on our previous cohorts, a prospective clinical trial was attempted; however, only two cases were ultimately enrolled in 27 months. A 664-nm semiconductor laser (100 J/cm²) was applied through an endoscope to the tumor lesion within 6 h of an intravenous injection of 40 mg/m² TPS according to the protocol for lung cancer. Case 1 was an 82-y.o. female patient with BDC at the left hepatic duct with biliary obstruction, percutaneous transhepatic biliary drainage (PTBD) was achieved, and the patient did not consent to surgery. She was followed up for 15 months to search for non-surgical treatments and eventually received PDT. Although mild photosensitivity occurred, she was discharged without severe adverse events. Biliary stenosis markedly extended and a PTBD tube was scheduled at 1 month. However, cancer immediately metastasized to the liver and she died 155 days after PDT. Case 2 was a 70-y.o. female with perihilar BDC and multiple biliary stenoses. Multiple biliary stenting was considered to be difficult. She received PDT and no adverse events were observed. Biliary stenoses markedly improved and multiple stenting was successfully performed. On day 132, she died of cancer progression. These two cases demonstrated the safety and efficacy of biliary malignant stenosis soon after PDT; however, long-term survival and a sufficient quality of life were not achieved. The combination of the PDT protocol and system chemotherapy or brachytherapy needs to be examined in clinical trials for advanced stage BDC.

UHRF1 depletion and HDAC inhibition reactivate epigenetically silenced genes in colorectal cancer cells

BACKGROUND

Ubiquitin-like protein containing PHD and RING finger domains 1 (UHRF1) is a major regulator of epigenetic mechanisms and is overexpressed in various human malignancies. In this study, we examined the involvement of UHRF1 in aberrant DNA methylation and gene silencing in colorectal cancer (CRC).

RESULTS

CRC cell lines were transiently transfected with siRNAs targeting UHRF1, after which DNA methylation was analyzed using dot blots, bisulfite pyrosequencing, and Infinium HumanMethylation450 BeadChip assays. Gene expression was analyzed using RT-PCR and gene expression microarrays. Depletion of UHRF1 rapidly induced genome-wide DNA demethylation in CRC cells. Infinium BeadChip assays and bisulfite pyrosequencing revealed significant demethylation across entire genomic regions, including CpG islands, gene bodies, intergenic regions, and repetitive elements. Despite the substantial demethylation, however, UHRF1 depletion only minimally reversed CpG island hypermethylation-associated gene silencing. By contrast, the combination of UHRF1 depletion and histone deacetylase (HDAC) inhibition reactivated the silenced genes and strongly suppressed CRC cell proliferation. The combination of UHRF1 depletion and HDAC inhibition also induced marked changes in the gene expression profiles such that cell cycle-related genes were strikingly downregulated.

CONCLUSIONS

Our results suggest that (i) maintenance of DNA methylation in CRC cells is highly dependent on UHRF1; (ii) UHRF1 depletion rapidly induces DNA demethylation, though it is insufficient to fully reactivate the silenced genes; and (iii) dual targeting of UHRF1 and HDAC may be an effective new therapeutic strategy.

Abstract P1-06-11: Microsatellite instability in triple negative breast cancers

Background:Microsatellite instability (MSI) is a phenotype resulting from defect in mismatch repair genes. The Food and Drug Administration approved anti-programmed death 1 (PD-1) immune checkpoint inhibitor for any solid tumor with MSI-high (MSI-H). Some tumors had good response to PD-1 blockade and it is a promising treatment for a part of refractory breast cancers. Our goal was to determine the frequency of MSI in triple negative breast cancer (TNBC), one of the most clinically aggressive subtypes.

Patients and Methods:This study included 228 patients with primary TNBC underwent resection without neoadjuvant chemotherapy between January 2004 and December 2014. Genomic DNA was extracted from formalin-fixed and paraffin-embedded tissue. Tumor and control DNA were amplified by polymerase chain reaction at the following 5 microsatellite markers: NR-21, BAT-26, BAT-25, NR-24, MONO-27. We classified the tumors as microsatellite stable(MSS), MSI-low or MSI-H.

Results: The mean age of patients was 59 years (range: 30-89) and all were women. T1 tumors were 57.9% and N0 were 67.5%. Meanwhile, the tumors with nuclear grade 3 were 66.2% and high Ki-67 (> 30%) were 66.7%. Among the 228 tumors, 222 tumors (97.4%) revealed MSS, of which 6 (2.6%) revealed MSI and 2 (0.9%) were MSI-H. Among the MSI tumors, T and N factor were showed as follows: T1: 2 tumors, T2: 3 tumors, T3: 1 tumor, N0: 5 tumors and N1: 1 tumor. Of two MSI-H tumors, one showed T1N0 and another showed T2N0. The both of them showed nuclear grade 3, high Ki-67 (> 30%) and had common following instable markers: NR-21, BAT-26 and BAT-25.

Conclusions: Our results demonstrated that the frequency of MSI-H was 0.9% (2/228). MSI might not be useful as a biomarker for immune check point inhibitors. MSI should be combined with another biomarker such as tumor mutational burden in TNBC.

Citation Format: Kurata K, Kubo M, Mori H, Kawaji H, Motoyama Y, Kuroki L, Yamada M, Kaneshiro K, Kai M, Nakamura M. Microsatellite instability in triple negative breast cancers [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-06-11.

Abstract P4-06-22: Transcription factor T-bet and PD-L1 expression in tumor microenvironment of triple-negative breast cancer

Background: Many analyzes regarding immunotherapies using checkpoint blockade has made it clear that tumor infiltrating lymphocytes (TILs) plays an important role in treating cancers with high levels of somatic mutations such as triple-negative breast cancer (TNBC). We reported the relationship between TILs and PD-L1 expression, and revealed that high-TILs/positive-PD-L1 expression population in TNBC was associated with better prognosis (Oncotarget 2017). However, its molecular mechanism is still unclear. Meanwhile, T-box transcription factor 21 (T-bet) which regulates effecter T-cells activation is derived by stimulation of T-cell receptor and IL-12. Activated T-cells work as antitumor lymphocytes by enhancing the production of cytokines such as INFγ. We focused on T-bet and examined the function of activated T-cells.

Patients and Methods: This study included 242 patients with primary TNBC who underwent resection without neoadjuvant chemotherapy at our three hospitals between January 2004 and December 2014. The immunohistochemistry scoring for CD8 and T-bet expression on TILs was defined as ≥30 per 0.00625mm2. PD-L1 positivity was defined as ≥1% of tumor cells staining positive for PD-L1.

Results: Of the 242 TNBC, CD8 on TILs was expressed as positive in 127 (52.5%) tumors, T-bet on TILs was expressed as positive in 67 (27.7%) tumors, and PD-L1 expression on tumor cells was expressed as positive in 99 (40.9%) tumors. T-bet expression was significantly correlated with CD8 expression (P<0.0001) and PD-L1 expression (P=0.0004). There was no significant difference in recurrence free survival (RFS) and overall survival (OS) regardless of CD8 or PD-L1expression level. Meanwhile, the patients with T-bet-positive tumors had a longer OS, compared to those with T-bet-negative tumors (P = 0.13 in RFS and P = 0.047 in OS). The multivariate analysis revealed that T-bet expression on TILswas an independent and positive prognostic factor for OS(HR = 0.5, 95%CI 0.1-0.9, P = 0.035).

Conclusion: OS was significantly longer among patients with high T-bet expressing TNBC. These results may validate the significance of T-bet as a biomarker for various immunotherapies in TNBC.

Citation Format: Mori H, Kubo M, Kai M, Kurata K, Kawaji H, Kaneshiro K, Motoyama Y, Kuroki R, Yamada M, Nishimura R, Okido M, Oda Y, Nakamura M. Transcription factor T-bet and PD-L1 expression in tumor microenvironment of triple-negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-06-22.

Surface microstructures are associated with mutational intratumoral heterogeneity in colorectal tumors

BACKGROUND

Recent studies revealed that colorectal tumors are composed of genetically diverse subclones. We aimed to clarify whether the surface microstructures of colorectal tumors are associated with genetic intratumoral heterogeneity (ITH).

METHODS

The surface microstructures (pit patterns) of colorectal tumors were observed using magnifying endoscopy, and biopsy specimens were obtained from respective areas when tumors exhibited multiple pit patterns. A total of 711 specimens from 477 colorectal tumors were analyzed for BRAF, KRAS and TP53 mutations using pyrosequencing and direct sequencing. A panel of cancer-related genes was analyzed through targeted sequencing in 7 tumors.

RESULTS

Colorectal tumors with multiple pit patterns exhibited more advanced pit patterns and higher frequencies of KRAS and/or TP53 mutations than tumors with a single pit pattern. In tumors with multiple pit patterns, mutations were observed as public (common to all areas) or private (specific to certain areas), and private KRAS and/or TP53 mutations were often variable and unrelated to the pit pattern grade. Notably, invasive CRCs frequently exhibited public TP53 mutations, even in adenomatous areas, which is indicative of their early malignant potential. Targeted sequencing revealed additional public and private mutations in tumors with multiple pit patterns, indicating their single clonal origin.

CONCLUSIONS

Our results suggest intratumoral pit pattern variation does not simply reflect the process of colorectal tumor evolution, but instead represents genetically diverse subclones, and this diversity may be associated with malignant potential.

Antimicrobial resistance in leprosy: results of the first prospective open survey conducted by a WHO surveillance network for the period 2009-15

OBJECTIVES

Antimicrobial resistance (AMR) is a priority for surveillance in bacterial infections. For leprosy, AMR has not been assessed because Mycobacterium leprae does not grow in vitro. We aim to obtain AMR data using molecular detection of resistance genes and to conduct a prospective open survey of resistance to antileprosy drugs in countries where leprosy is endemic through a WHO surveillance network.

METHODS

From 2009 to 2015, multi-bacillary leprosy cases at sentinel sites of 19 countries were studied for resistance to rifampicin, dapsone and ofloxacin by PCR sequencing of the drug-resistance-determining regions of the genes rpoB, folP1 and gyrA.

RESULTS

Among 1932 (1143 relapse and 789 new) cases studied, 154 (8.0%) M. leprae strains were found with mutations conferring resistance showing 182 resistance traits (74 for rifampicin, 87 for dapsone and 21 for ofloxacin). Twenty cases showed rifampicin and dapsone resistance, four showed ofloxacin and dapsone resistance, but no cases were resistant to rifampicin and ofloxacin. Rifampicin resistance was observed among relapse (58/1143, 5.1%) and new (16/789, 2.0%) cases in 12 countries. India, Brazil and Colombia reported more than five rifampicin-resistant cases.

CONCLUSIONS

This is the first study reporting global data on AMR in leprosy. Rifampicin resistance emerged, stressing the need for expansion of surveillance. This is also a call for vigilance on the global use of antimicrobial agents, because ofloxacin resistance probably developed in relation to the general intake of antibiotics for other infections as it is not part of the multidrug combination used to treat leprosy.

Progression-dependent transport heterogeneity of breast cancer liver metastases as a factor in therapeutic resistance

Metastatic disease is a major cause of mortality in cancer patients. While many drug delivery strategies for anticancer therapeutics have been developed in preclinical studies of primary tumors, the drug delivery properties of metastatic tumors have not been sufficiently investigated. Therapeutic efficacy hinges on efficient drug permeation into the tumor microenvironment, which is known to be heterogeneous thus potentially making drug permeation heterogeneous, also. In this study, we have identified that 4 T1 liver metastases, treated with pegylated liposomal doxorubicin, have unfavorable and heterogeneous transport of doxorubicin. Our drug extravasation results differ greatly from analogous studies with 4 T1 tumors growing in the primary site. A probabilistic tumor population model was developed to estimate drug permeation efficiency and drug kinetics of liver metastases by integrating the transport and structural properties of tumors and delivered drugs. The results demonstrate significant heterogeneity in metastases with regard to transport properties of doxorubicin within the same animal model, and even within the same organ. These results also suggest that the degree of heterogeneity depends on the stage of tumor progression and that differences in transport properties can define transport-based tumor phenotypes. These findings may have valuable clinical implications by illustrating that therapeutic agents can permeate and eliminate metastases of "less resistant" transport phenotypes, while sparing tumors with more "resistant" transport properties. We anticipate that these results could challenge the current paradigm of drug delivery into metastases, highlight potential caveats for therapies that may alter tumor perfusion, and deepen our understanding of the emergence of drug transport-based therapeutic resistance.

Errata: Internal doses from radionuclides and their health effects following the Fukushima accident (J. Radiol. Prot. 2018 38 1253-68)

This article presents errata on a published article.

DOT1L inhibition blocks multiple myeloma cell proliferation by suppressing IRF4-MYC signaling

Epigenetic alterations play an important role in the pathogenesis in multiple myeloma, but their biological and clinical relevance is not fully understood. Here, we show that DOT1L, which catalyzes methylation of histone H3 lysine 79, is required for myeloma cell survival. DOT1L expression levels were higher in monoclonal gammopathy of undetermined significance and smoldering multiple myeloma than in normal plasma cells. Treatment with a DOT1L inhibitor induced cell cycle arrest and apoptosis in myeloma cells, and strongly suppressed cell proliferation in vitro. The anti-myeloma effect of DOT1L inhibition was confirmed in a mouse xenograft model. Chromatin immunoprecipitation-sequencing and microarray analysis revealed that DOT1L inhibition downregulated histone H3 lysine 79 dimethylation and expression of IRF4-MYC signaling genes in myeloma cells. In addition, DOT1L inhibition upregulated genes associated with immune responses and interferon signaling. Myeloma cells with histone modifier mutations or lower IRF4/MYC expression were less sensitive to DOT1L inhibition, but with prolonged treatment, anti-proliferative effects were achieved in these cells. Our data suggest that DOT1L plays an essential role in the development of multiple myeloma and that DOT1L inhibition may provide new therapies for myeloma treatment.

Dysregulation of miRNA in chronic hepatitis B is associated with hepatocellular carcinoma risk after nucleos(t)ide analogue treatment

Hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC). Nucleos(t)ide analogue (NA) therapy effectively reduces the incidence of HCC, but it does not completely prevent the disease. Here, we show that dysregulation of microRNAs (miRNAs) is involved in post-NA HCC development. We divided chronic hepatitis B (CHB) patients who received NA therapy into two groups: 1) those who did not develop HCC during the follow-up period after NA therapy (no-HCC group) and 2) those who did (HCC group). miRNA expression profiles were significantly altered in CHB tissues as compared to normal liver, and the HCC group showed greater alteration than the no-HCC group. NA treatment restored the miRNA expression profiles to near-normal in the no-HCC group, but it was less effective in the HCC group. A number of miRNAs implicated in HCC, including miR-101, miR-140, miR-152, miR-199a-3p, and let-7g, were downregulated in CHB. Moreover, we identified CDK7 and TACC2 as novel target genes of miR-199a-3p. Our results suggest that altered miRNA expression in CHB contributes to HCC development, and that improvement of miRNA expression after NA treatment is associated with reduced HCC risk.

Subtypes of the Type II Pit Pattern Reflect Distinct Molecular Subclasses in the Serrated Neoplastic Pathway

BACKGROUND

Colorectal serrated lesions (SLs) are important premalignant lesions whose clinical and biological features are not fully understood.

AIMS

We aimed to establish accurate colonoscopic diagnosis and treatment of SLs through evaluation of associations among the morphological, pathological, and molecular characteristics of SLs.

METHODS

A total of 388 premalignant and 18 malignant colorectal lesions were studied. Using magnifying colonoscopy, microsurface structures were assessed based on Kudo's pit pattern classification system, and the Type II pit pattern was subcategorized into classical Type II, Type II-Open (Type II-O) and Type II-Long (Type II-L). BRAF/KRAS mutations and DNA methylation of CpG island methylator phenotype (CIMP) markers (MINT1, - 2, - 12, - 31, p16, and MLH1) were analyzed through pyrosequencing.

RESULTS

Type II-O was tightly associated with sessile serrated adenoma/polyps (SSA/Ps) with BRAF mutation and CIMP-high. Most lesions with simple Type II or Type II-L were hyperplastic polyps, while mixtures of Type II or Type II-L plus more advanced pit patterns (III/IV) were characteristic of traditional serrated adenomas (TSAs). Type II-positive TSAs frequently exhibited BRAF mutation and CIMP-low, while Type II-L-positive TSAs were tightly associated with KRAS mutation and CIMP-low. Analysis of lesions containing both premalignant and cancerous components suggested Type II-L-positive TSAs may develop into KRAS-mutated/CIMP-low/microsatellite stable cancers, while Type II-O-positive SSA/Ps develop into BRAF-mutated/CIMP-high/microsatellite unstable cancers.

CONCLUSIONS

These results suggest that Type II subtypes reflect distinct molecular subclasses in the serrated neoplasia pathway and that they could be useful hallmarks for identifying SLs at high risk of developing into CRC.

Assessment of epigenetic alterations in early colorectal lesions containing BRAF mutations

To clarify the molecular and clinicopathological characteristics of colorectal serrated lesions, we assessed the DNA methylation of cancer-associated genes in a cohort of BRAF-mutant precancerous lesions from 94 individuals. We then compared those results with the lesions' clinicopathological features, especially colorectal subsites. The lesions included hyperplastic polyps (n = 16), traditional serrated adenomas (TSAs) (n = 15), TSAs with sessile serrated adenomas (SSAs) (n = 6), SSAs (n = 49) and SSAs with dysplasia (n = 16). The prevalence of lesions exhibiting the CpG island methylator phenotype (CIMP) was lower in the sigmoid colon and rectum than in other bowel subsites, including the cecum, ascending, transverse and descending colon. In addition, several cancer-associated genes showed higher methylation levels within lesions in the proximal to sigmoid colon than in the sigmoid colon and rectum. These results indicate that the methylation status of lesions with BRAF mutation is strongly associated with their location, histological findings and neoplastic pathways. By contrast, no difference in aberrant DNA methylation was observed in normal-appearing background colonic mucosa along the bowel subsites, which may indicate the absence of an epigenetic field defect.

Epigenetic silencing of SMOC1 in traditional serrated adenoma and colorectal cancer

Colorectal sessile serrated adenoma/polyps (SSA/Ps) are well-known precursors of colorectal cancer (CRC) characterized by BRAF mutation and microsatellite instability. By contrast, the molecular characteristics of traditional serrated adenoma (TSAs) are not fully understood. We analyzed genome-wide DNA methylation in TSAs having both protruding and flat components. We identified 11 genes, including SMOC1, methylation of which progressively increased during the development of TSAs. SMOC1 was prevalently methylated in TSAs, but was rarely methylated in SSA/Ps (p < 0.001). RT-PCR and immunohistochemistry revealed that SMOC1 was expressed in normal colon and SSA/Ps, but its expression was decreased in TSAs. Ectopic expression of SMOC1 suppressed proliferation, colony formation and in vivo tumor formation by CRC cells. Analysis of colorectal lesions (n = 847) revealed that SMOC1 is frequently methylated in TSAs, high-grade adenomas and CRCs. Among these, SMOC1 methylation was strongly associated with KRAS mutation and CpG island methylator phenotype (CIMP)-low. These results demonstrate that epigenetic silencing of SMOC1 is associated with TSA development but is rarely observed in SSA/Ps. SMOC1 expression could thus be a diagnostic marker of serrated lesions, and SMOC1 methylation could play a role in neoplastic pathways in TSAs and conventional adenomas.

Evaluation of Urinary DNA Methylation as a Marker for Recurrent Bladder Cancer: A 2-Center Prospective Study

OBJECTIVE

To clarify the clinical utility of urinary DNA methylation for detection of intravesical recurrence of non-muscle invasive BCa (NMIBC), we performed a 2-center prospective study.

PATIENTS AND METHODS

A series of 207 self-voided urine samples were prospectively collected from 132 patients with NMIBC who had undergone transurethral resection of BCa. Methylation of miRNA genes (miR-9-3, miR-124-2, miR-124-3, and miR-137) was analyzed using bisulfite pyrosequencing. The primary end point was detection of intravesical recurrence; the secondary end point was prediction of late recurrence. The number of methylated genes (M-score) or quantitative level of methylation were compared with outcomes.

RESULTS

Twenty-six urine specimens were collected on the same day intravesical recurrence was detected, and 14 were collected from patients whose recurrences were found during the subsequent follow-up period (0-632 days, mean, 342.2 days). For detection of current recurrence, M-scores achieved 61.5% sensitivity and 74.0% specificity, and the area under the ROC curve was 0.71. Regarding prediction of late recurrence, patients with a high M-score (≥3) showed worse recurrence-free survival (P <.01). Multivariate analysis revealed that high M-scores were independently associated with current (P = .028) and late recurrence (P = .026). Elevated levels of urinary DNA methylation were also strongly associated with recurrence and radical cystectomy.

CONCLUSION

Our data suggest that urinary methylation of miRNA genes may be a useful marker for detecting and predicting BCa recurrence.

Downregulation of miR-186 is associated with metastatic recurrence of gastrointestinal stromal tumors

Although dysregulation of microRNAs (miRNAs/miRs) is a common feature of human malignancies, its involvement in gastrointestinal stromal tumors (GISTs) is not fully understood. The present study aimed to identify the miRNAs that perform a role in GIST metastasis. miRNA expression profiles from a series of 32 primary GISTs were analyzed using microarrays, and miR-186 was observed to be downregulated in tumors exhibiting metastatic recurrence. Reverse transcription-quantitative polymerase chain reaction analysis of an independent cohort of 100 primary GISTs revealed that low miR-186 expression is associated with metastatic recurrence and a poor prognosis. Inhibition of miR-186 in GIST-T1 cells promoted cell migration. Gene expression microarray analysis demonstrated that miR-186 inhibition upregulated a set of genes implicated in cancer metastasis, including insulin-like growth factor-binding protein 3, AKT serine/threonine kinase 2, hepatocyte growth factor receptor, CXC chemokine receptor 4 and epidermal growth factor-containing fibulin-like extracellular matrix protein 1. These results suggest that the downregulation of miR-186 is involved in the metastatic recurrence of GISTs, and that miR-186 levels could potentially be a predictive biomarker for clinical outcome.