Soochi Kim

Tumor evolution and intratumor heterogeneity of an epithelial ovarian cancer investigated using next-generation sequencing

BackgroundThe extent to which metastatic tumors further evolve by accumulating additional mutations is unclear and has yet to be addressed extensively using next-generation sequencing of high-grade serous ovarian cancer.MethodsEleven spatially separated tumor samples from the primary tumor and associated metastatic sites and two normal samples were obtained from a Stage IIIC ovarian cancer patient during cytoreductive surgery prior to chemotherapy. Whole exome sequencing and copy number analysis were performed. Omental exomes were sequenced with a high depth of coverage to thoroughly explore the variants in metastatic lesions. Somatic mutations were further validated by ultra-deep targeted sequencing to sort out false positives and false negatives. Based on the somatic mutations and copy number variation profiles, a phylogenetic tree was generated to explore the evolutionary relationship among tumor samples.ResultsOnly 6% of the somatic mutations were present in every sample of a given case with TP53 as the only known mutant gene consistently present in all samples. Two non-spatial clusters of primary tumors (cluster P1 and P2), and a cluster of metastatic regions (cluster M) were identified. The patterns of mutations indicate that cluster P1 and P2 diverged in the early phase of tumorigenesis, and that metastatic cluster M originated from the common ancestral clone of cluster P1 with few somatic mutations and copy number variations.ConclusionsAlthough a high level of intratumor heterogeneity was evident in high-grade serous ovarian cancer, our results suggest that transcoelomic metastasis arises with little accumulation of somatic mutations and copy number alterations in this patient.

Resveratrol triggers ER stress-mediated apoptosis by disrupting N-linked glycosylation of proteins in ovarian cancer cells

Malignant tumors have a high glucose demand and alter cellular metabolism to survive. Herein, focusing on the utility of glucose metabolism as a therapeutic target, we found that resveratrol induced endoplasmic reticulum (ER) stress-mediated apoptosis by interrupting protein glycosylation in a cancer-specific manner. Our results indicated that resveratrol suppressed the hexosamine biosynthetic pathway and interrupted protein glycosylation through GSK3β activation. Application of either biochemical intermediates of the hexosamine pathway or small molecular inhibitors of GSK3β reversed the effects of resveratrol on the disruption of protein glycosylation. Additionally, an ER UDPase, ectonucleoside triphosphate diphosphohydrolase 5 (ENTPD5), modulated protein glycosylation by Akt attenuation in response to resveratrol. By inhibition or overexpression of Akt functions, we confirmed that the glycosylation activities were dependent on ENTPD5 expression and regulated by the action of Akt in ovarian cancer cells. Resveratrol-mediated disruption of protein glycosylation induced cellular apoptosis as indicated by the up-regulation of GADD153, followed by the activation of ER-stress sensors (PERK and ATF6α). Thus, our results provide novel insight into cancer cell metabolism and protein glycosylation as a therapeutic target for cancers.

Risks related with withholding and resuming anticoagulation in patients with non‐variceal upper gastrointestinal bleeding while on warfarin therapy

Background:  The use of warfarin is growing for the prevention or treatment of cardiovascular or cerebrovascular diseases. The risk of haemorrhagic side effects is increased in patients taking warfarin.

Ascites modulates cancer cell behavior, contributing to tumor heterogeneity in ovarian cancer.

Malignant ascites constitute a unique tumor microenvironment providing a physical structure for the accumulation of cellular and acellular components. Ascites is initiated and maintained by physical and biological factors resulting from underlying disease and forms an ecosystem that contributes to disease progression. It has been demonstrated that the cellular contents and the molecular signatures of ascites change continuously during the course of a disease. Over the past decade, increasing attention has been given to the characterization of components of ascites and their role in the progression of ovarian cancer, the most malignant gynecologic cancer in women. This review will discuss the role of ascites in disease progression, in terms of modulating cancer cell behavior and contributing to tumor heterogeneity.

Malignant ascites enhances migratory and invasive properties of ovarian cancer cells with membrane bound IL-6R in vitro

Transcoelomic route is the most common and the earliest route of metastasis, causing the ascites formation in advanced epithelial ovarian cancer (EOC). We demonstrated that interleukin 6 (IL-6) is enriched in the malignant ascites from patients with ovarian cancer, which enhanced invasive properties of EOC cells. Interestingly, the expression of IL-6R on cell membrane of EOC cells correlated with ascites-induced invasion. Selective knockdown of IL-6R or inhibition with IL-6 neutralizing antibody, suppressed the stimulatory effects of ascites on EOC invasion. Moreover, the ascites treatment induced the phosphorylation of JAK2-STAT3 and use of selective inhibitors of JAK2 and STAT3, blocked the expression of epithelial-mesenchymal transition related proteins in parallel with the suppression of EOC invasion. Thus, IL-6/IL-6R mediated JAK2-STAT3 signaling pathway could be a promising therapeutic target for anticancer therapy in ovarian cancer patients with ascites.

Adipose Stromal Cells from Visceral and Subcutaneous Fat Facilitate Migration of Ovarian Cancer Cells via IL-6/JAK2/STAT3 Pathway.

Purpose Adipose stromal cells (ASCs) play an important regulatory role in cancer progression and metastasis by regulating systemic inflammation and tissue metabolism. This study examined whether visceral and subcutaneous ASCs (V- and S-ASCs) facilitate the growth and migration of ovarian cancer cells. Materials and Methods CD45– and CD31– double-negative ASCs were isolated from the subcutaneous and visceral fat using magnetic-activated cell sorting. Ovarian cancer cells were cultured in conditioned media (CM) obtained from ASCs to determine the cancer-promoting effects of ASCs. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, Boyden chamber assay, and western blotting were performed to determine the proliferative activity, migration ability, and activation of the JAK2/STAT3 pathway, respectively. Results CM from ASCs enhanced the migration of the ovarian cancer line, SKOV3, via activation of the JAK2/STAT3 signaling pathway. Interestingly, in response to ASC-CM, the ascites cells derived from an ovarian cancer patient showed an increase in growth and migration. The migration of ovarian cancer cells was suppressed by blocking the activation of JAK2 and STAT3 using a neutralizing antibody against interleukin 6, small molecular inhibitors (e.g., WP1066 and TG101348), and silencing of STAT3 using siRNA. Anatomical differences between S- and V-ASCs did not affect the growth and migration of the ovarian cancer cell line and ascites cells from the ovarian cancer patients. Conclusion ASCs may regulate the progression of ovarian cancer, and possibly provide a potential target for anticancer therapy.

Pro-inflammatory M1 macrophage enhances metastatic potential of ovarian cancer cells through NF-κB activation

Obesity is a serious health problem and critically related to poor prognosis in cancer, presumably through induction of chronic inflammation. The major culprit for cancer progression in obesity is presumed to be macrophages. Accumulation of macrophages in adipose tissue due to obesity induced chronic inflammation has been observed. However, obesity‐induced macrophage accumulation related to ovarian cancer progression remains unclear. So, the role of macrophage in cancer progression is needed to be further defined for therapeutic intervention. Here we determined the effect of macrophage type 1 (M1 macrophage) on ovarian cancer cells in relation to the metastasis. Ovarian cancer cell lines (PA‐1, SKOV3) and monocyte‐derived macrophages were used in this study. Treatment with M1 macrophage conditioned media on ovarian cancer cells increased the metastatic potential, such as migration and invasion capabilities. Interestingly, upon treatment with M1 macrophage conditioned media, nuclear translocation of NF‐κB, p60, and p50, from the cytosol was enhanced together with increased transcriptional activity of the NF‐κB. Pre‐treatment with TPCK (NF‐κB inhibitor) and NF‐κB siRNA on ovarian cancer cells suppressed M1 macrophage‐induced metastatic potential. Furthermore, Treatment of TNF‐α on ovarian cancer cells showed NF‐κB activation. Co‐treatment with TNF‐α inhibitor, etanercept, and M1 macrophage conditioned media on ovarian cancer cell lines reversed M1 macrophage conditioned media induced NF‐κB activation. Taken together, TNF‐α released from M1 macrophage increased metastatic potential in ovarian cancer cells through the activation of NF‐κB signaling pathway. These results provide a new insight into the critical role of M1 macrophage in the tumor microenvironment in ovarian cancer.

Tumour microenvironment on mitochondrial dynamics and chemoresistance in cancer

Abstract Mitochondria, evolutionally acquired symbionts of eukaryotic cells, are essential cytoplasmic organelles. They are structurally dynamic organelles that continually go through fission and fusion processes in response to various stimuli. Tumour tissue is composed of not just cancer cells but also various cell types like fibroblasts, mesenchymal stem and immune cells. Mitochondrial dynamics of cancer cells has been shown to be significantly affected by features of tumour microenvironment such as hypoxia, inflammation and energy deprivation. The interactions of cancer cells with tumour microenvironment like hypoxia give rise to the inter- and intratumoural heterogeneity, causing chemoresistance. In this review, we will focus on the chemoresistance by tumoural heterogeneity in relation to mitochondrial dynamics of cancer cells. Recent findings in molecular mechanisms involved in the control of mitochondrial dynamics as well as the impact of mitochondrial dynamics on drug sensitivity in cancer are highlighted in the current review.

Tumor evolution and chemoresistance in ovarian cancer.

Development of novel strategies to overcome chemoresistance is central goal in ovarian cancer research. Natural history of the cancer development and progression is being reconstructed by genomic datasets to understand the evolutionary pattern and direction. Recent studies suggest that intra-tumor heterogeneity (ITH) is the main cause of treatment failure by chemoresistance in many types of cancers including ovarian cancer. ITH increases the fitness of tumor to adapt to incompatible microenvironment. Understanding ITH in relation to the evolutionary pattern may result in the development of the innovative approach based on individual variability in the genetic, environment, and life style. Thus, we can reach the new big stage conquering the cancer. In this review, we will discuss the recent advances in understanding ovarian cancer biology through the use of next generation sequencing (NGS) and highlight areas of recent progress to improve precision medicine in ovarian cancer.

Evaluating Tumor Evolution via Genomic Profiling of Individual Tumor Spheroids in a Malignant Ascites from a Patient with Ovarian Cancer Using a Laser-aided Cell Isolation Technique

Background Epithelial ovarian cancer (EOC) is a silent but mostly lethal gynecologic malignancy. Most patients present with malignant ascites and peritoneal seeding at diagnosis. In the present study, we used a laser-aided isolation technique to investigate the clonal relationship between the primary tumor and tumor spheroids found in the malignant ascites of an EOC patient. Somatic alteration profiles of ovarian cancer-related genes were determined for eight spatially separated samples from primary ovarian tumor tissues and ten tumor spheroids from the malignant ascites using next-generation sequencing. Results We observed high levels of intra-tumor heterogeneity (ITH) in copy number alterations (CNAs) and single-nucleotide variants (SNVs) in the primary tumor and the tumor spheroids. As a result, we discovered that tumor cells in the primary tissues and the ascites were genetically different lineages. We categorized the CNAs and SNVs into clonal and subclonal alterations according to their distribution among the samples. Also, we identified focal amplifications and deletions in the analyzed samples. For SNVs, a total of 171 somatic mutations were observed, among which 66 were clonal mutations present in both the primary tumor and the ascites, and 61 and 44 of the SNVs were subclonal mutations present in only the primary tumor or the ascites, respectively. Conclusions Based on the somatic alteration profiles, we constructed phylogenetic trees and inferred the evolutionary history of tumor cells in the patient. The phylogenetic trees constructed using the CNAs and SNVs showed that two branches of the tumor cells diverged early from an ancestral tumor clone during an early metastasis step in the peritoneal cavity. Our data support the monophyletic spread of tumor spheroids in malignant ascites.