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The Objectives of this study is to review various peer support practices of cancer survivors in Japan and to find effective support components. We reviewed the materials on cancer peer support published by the government and research papers on cancer peer support in the fields of psychology and nursing. National peer support activities include training of peer supporters to provide counseling and support by cancer survivors; however, these activities are not very widespread. On the other hand, where peer support activities are carried out effectively, dialogue between the peer who supports cancer patients and the patient receiving the support is on an equal footing. The Cancer Philosophy Clinic Medical Café started by Dr. Okio HINO is one such activity. A medical café has the effect of raising positive emotions and lowering negative emotions, and contribute to cancer education. The perspective of peers supporting and interacting on an equal footing is important for effective peer support activities. In peer support by the government, rather than providing counseling training to those who practice peer support, activities will develop and last longer by creating a relationship in which people can talk freely on the same level as peers.

Supplementary Figure S6 shows that restoring MFGE8 abolishes apoptosis by re-activating the FAK-AKT pathway.

Figure S1. RHEB mRNA expression in different types of cancer. Figure S2. In vivo growth of MeT-5A mesothelial cells expressing exogenous RHEBL1. Figure S3. RHEBL1 binds to SmgGDS. Figure S4. SmgGDS knockdown suppresses the proliferation of mesothelial cells expressing exogenous RHEBL1. Figure S5. SmgGDS knockdown suppresses the growth of PTEN-deficient MM cells in vitro. Figure S6. Subcellular RHEBL1 localization. Figure S7. SmgGDS knockdown alters RHEBL1 localization in PTEN-deficient MM cells. Figure S8. Amino acid stimulation does not affect RHEBL1 subcellular localization. Figure S9. RHEBL1 farnesylation is essential for SmgGDS binding.

Malignant mesothelioma (MM) is an aggressive tumor that typically develops after a long latency following asbestos exposure. Although mechanistic target of rapamycin complex 1 (mTORC1) activation enhances MM cell growth, the mTORC1 inhibitor everolimus has shown limited efficacy in clinical trials of MM patients. We explored the mechanism underlying mTORC1 activation in MM cells and its effects on cell proliferation and progression. Analysis of the expression profiles of 87 MMs from The Cancer Genome Atlas revealed that 40 samples (46%) displayed altered expression of RPTOR (mTORC1 component) and genes immediately upstream that activate mTORC1. Among them, we focused on RHEB and RHEBL1, which encode direct activators of mTORC1. Exogenous RHEBL1 expression enhanced MM cell growth, indicating that RHEB–mTORC1 signaling acts as a pro-oncogenic cascade. We investigated molecules that directly activate RHEBs, identifying SmgGDS as a novel RHEB-binding protein. SmgGDS knockdown reduced mTORC1 activation and inhibited the proliferation of MM cells with mTORC1 activation. Interestingly, SmgGDS displayed high binding affinity with inactive GDP-bound RHEBL1, and its knockdown reduced cytosolic RHEBL1 without affecting its activation. These findings suggest that SmgGDS retains GDP-bound RHEBs in the cytosol, whereas GTP-bound RHEBs are localized on intracellular membranes to promote mTORC1 activation. We revealed a novel role for SmgGDS in the RHEB–mTORC1 pathway and its potential as a therapeutic target in MM with aberrant mTORC1 activation.Implications:Our data showing that SmgGDS regulates RHEB localization to activate mTORC1 indicate that SmgGDS can be used as a new therapeutic target for MM exhibiting mTORC1 activation.

Supplementary Figure Legends

Supplementary Table S1 shows the selected genes with statistically significant changes in transcriptome analysis using two different shRNA constructs.

Malignant pleural mesothelioma (MPM) is a highly aggressive tumor that has a low overall survival; however, no significant treatment advances have been made in the past 15 years. Large-scale molecular studies have identified a poor prognostic subset of MPM linked to the epithelial–mesenchymal transition (EMT) that may contribute toward resistance to chemotherapy, suggesting that EMT could be targeted to treat patients with MPM. Previously, we reported that histone modifiers regulating EMT could be therapeutic targets; therefore, in this study, we investigated whether targeting lysine-specific demethylase 1 (LSD1/KDM1), a histone-modifying enzyme responsible for demethylating histone H3 lysine 4 and lysine 9, could represent a novel therapeutic strategy for MPM. We suppressed LSD1 and investigated the EMT phenotype using EMT marker expression and wound-healing assay; and chemosensitivity using apoptosis assay. We found that suppressing LSD1 induces an epithelial phenotype in sarcomatoid MPM cells, while attenuating the mesenchymal phenotype sensitized MPM cells to cisplatin-induced apoptosis. Subsequent genome-wide identification, comprehensive microarray analysis, and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) to assess genome-wide changes in chromatin accessibility suggested that LSD1 directly regulates milk fat globulin protein E8 (MFGE8), an integrin ligand that is involved in the FAK pathway. Furthermore, we found that LSD1 regulates the mesenchymal phenotype and apoptosis by activating the FAK–AKT–GSK3β pathway via a positive feedback loop involving MFGE8 and Snail expression, thereby leading to cisplatin resistance.Implications:This study suggests that LSD1 regulates the mesenchymal phenotype and apoptosis, and that LSD1 inhibitors could be combined with the cisplatin as a novel therapy for patients with MPM.

Background Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that is associated with neurological symptoms, including autism spectrum disorder. Tuberous sclerosis complex is caused by pathogenic germline mutations of either the TSC1 or TSC2 gene, but somatic mutations were identified in both genes, and the combined effects of TSC1 and TSC2 mutations have been unknown. Methods The present study investigated social behaviors by the social interaction test and three-chambered sociability tests, effects of rapamycin treatment, and gene expression profiles with a gene expression microarray in Tsc1 and Tsc2 double heterozygous mutant (TscD+/−) mice. Results TscD+/− mice exhibited impairments in social behaviors, and the severity of impairments was similar to Tsc2+/− mice rather than Tsc1+/− mice. Impairments in social behaviors were rescued by rapamycin treatment in all mutant mice. Gene expression profiles in the brain were greatly altered in TscD+/− mice more than in Tsc1+/− and Tsc2+/− mice. The gene expression changes compared with wild type (WT) mice were similar between TscD+/− and Tsc2+/− mice, and the overlapping genes whose expression was altered in mutant mice compared with WT mice were enriched in the neoplasm- and inflammation-related canonical pathways. The “signal transducer and activator of transcription 3, interferon regulatory factor 1, interferon regulatory factor 4, interleukin-2R α chain, and interferon-γ” signaling pathway, which is initiated from signal transducer and activator of transcription 4 and PDZ and LIM domain protein 2, was associated with impairments in social behaviors in all mutant mice. Limitations It is unclear whether the signaling pathway also plays a critical role in autism spectrum disorders not caused by Tsc1 and Tsc2 mutations. Conclusions These findings suggest that TSC1 and TSC2 double mutations cause autistic behaviors similarly to TSC2 mutations, although significant changes in gene expression were attributable to the double mutations. These findings contribute to the knowledge of genotype–phenotype correlations in TSC and suggest that mutations in both the TSC1 and TSC2 genes act in concert to cause neurological symptoms, including autism spectrum disorder.

Mesothelioma is a highly aggressive tumour associated with asbestos exposure and is histologically classified into three types: epithelioid-type, sarcomatoid-type and biphasic-type. The prognosis of mesothelioma patients is poor and there is no effective molecular-targeting therapy as yet. ERC/mesothelin is a glycoprotein that is highly expressed on several types of cancers including epithelioid mesothelioma, but also expressed on normal mesothelial cells. This is a predicted reason why there is no clinically approved therapeutic antibody targeting ERC/mesothelin. In the present study, we focussed on the differential glycosylation between ERC/mesothelin present on epithelioid mesothelioma and that on normal mesothelial cells and aimed to reveal a distinct feature of epithelioid mesothelioma cells. Lectin microarray analysis of ERC/mesothelin using cells and patient specimens showed significantly stronger binding of PHA-E4 lectin, which recognizes complex-type N-glycans having a so-called bisecting-GlcNAc structure, to ERC/mesothelin from epithelioid mesothelioma cells than that from normal mesothelial cells. Further, liquid chromatography/mass spectrometry analysis on ERC/mesothelin from epithelioid mesothelioma cells confirmed the presence of a bisecting-GlcNAc attached to Asn388 of ERC/mesothelin. These results suggest that this glycoproteome could serve as a potential target for the generation of a highly selective and safe therapeutic antibody for epithelioid mesothelioma., Graphical Abstract

The expression of Renal Carcinoma (ERC)/mesothelin is enhanced in a variety of cancers. ERC/mesothelin contributes to cancer progression by modulating cell signals that regulate proliferation and apoptosis. Based on such biological insights, ERC/mesothelin has become a molecular target for the treatment of mesothelioma, pancreatic cancer, and ovarian cancer. Recent studies revealed about 50–60% of colorectal adenocarcinomas also express ERC/mesothelin. Therefore, colorectal cancer can also be a potential target of the treatment using an anti-ERC/mesothelin antibody. We previously demonstrated an anti-tumor effect of anti-ERC antibody 22A31 against mesothelioma. In this study, we investigated the effect of 22A31 on a colorectal adenocarcinoma cell line, HCT116. The cells were xenografted into BALB/c nu/nu mice. All mice were randomly allocated to either an antibody treatment group with 22A31 or isotype-matched control IgG1κ. We compared the volume of subsequent tumors, and tumors were pathologically assessed by immunohistochemistry. Tumors treated with 22A31 were significantly smaller than those treated with IgG1κ and contained significantly fewer mitotic cells with Ki67 staining. We demonstrated that 22A31 exhibited a growth inhibitory property on HCT116. Our results implied that ERC/mesothelin-targeted therapy might be a promising treatment for colorectal cancer.

Tuberous sclerosis complex (TSC) is caused by mutations inTsc1orTsc2, whose gene products inhibit the small G-protein Rheb1. Rheb1 activates mTORC1, which may cause refractory epilepsy, intellectual disability, and autism. The mTORC1 inhibitors have been used for TSC patients with intractable epilepsy. However, its effectiveness for cognitive symptoms remains unclear. We found a new signaling pathway for synapse formation through Rheb1 activation, but not mTORC1. Here, we show that treatment with the farnesyltransferase inhibitor lonafarnib increased unfarnesylated (inactive) Rheb1 levels and restored synaptic abnormalities in culturedTsc2+/−neurons, whereas rapamycin did not enhance spine synapse formation. Lonafarnib treatment also restored the plasticity-related Arc (activity-regulated cytoskeleton-associated protein) expression in culturedTsc2+/−neurons. Lonafarnib action was partly dependent on the Rheb1 reduction with syntenin. Oral administration of lonafarnib increased unfarnesylated protein levels without affecting mTORC1 and MAP (mitogen-activated protein (MAP)) kinase signaling, and restored dendritic spine morphology in the hippocampi of maleTsc2+/−mice. In addition, lonafarnib treatment ameliorated contextual memory impairments and restored memory-related Arc expression in maleTsc2+/−micein vivo. HeterozygousRheb1knockout in maleTsc2+/−mice reproduced the results observed with pharmacological treatment. These results suggest that the Rheb1 activation may be responsible for synaptic abnormalities and memory impairments inTsc2+/−mice, and its inhibition by lonafarnib could provide insight into potential treatment options for TSC-associated neuropsychiatric disorders.SIGNIFICANCE STATEMENTTuberous sclerosis complex (TSC) is an autosomal-dominant disease that causes neuropsychiatric symptoms, including intractable epilepsy, intellectual disability (ID) and autism. No pharmacological treatment for ID has been reported so far. To develop a pharmacological treatment for ID, we investigated the mechanism of TSC and found that Rheb1 activation is responsible for synaptic abnormalities in TSC neurons. To inhibit Rheb1 function, we used the farnesyltransferase inhibitor lonafarnib, because farnesylation of Rheb1 is required for its activation. Lonafarnib treatment increased inactive Rheb1 and recovered proper synapse formation and plasticity-related Arc (activity-regulated cytoskeleton-associated protein) expression in TSC neurons. Furthermore,in vivolonafarnib treatment restored contextual memory and Arc induction in TSC mice. Together, Rheb1 inhibition by lonafarnib could provide insight into potential treatments for TSC-associated ID.

Ionizing radiation can damage DNA and, therefore, is a risk factor for cancer. Eker rats, which carry a heterozygous germline mutation in the tumor‐suppressor gene tuberous sclerosis complex 2 (Tsc2), are susceptible to radiation‐induced renal carcinogenesis. However, the molecular mechanisms involved in Tsc2 inactivation are unclear. We subjected Fischer 344 × Eker (Long Evans Tsc2 +/−) F1 hybrid rats to gamma‐irradiation (2 Gy) at gestational day 19 (GD19) or postnatal day 5 (PND5) and investigated the patterns of genomic alterations in the Tsc2 allele of renal tumors that developed at 1 year after irradiation (N = 24 tumors for GD19, N = 10 for PND5), in comparison with spontaneously developed tumors (N = 8 tumors). Gamma‐irradiation significantly increased the multiplicity of renal tumors. The frequency of LOH at the chromosome 10q12 region, including the Tsc2 locus, was 38%, 29% and 60% in renal carcinomas developed from the nonirradiated, GD19 and PND5 groups, respectively. Array comparative genomic hybridization analysis revealed that the LOH patterns on chromosome 10 in renal carcinomas were classified into chromosomal missegregation, mitotic recombination and chromosomal deletion types. LOH of the interstitial chromosomal deletion type was observed only in radiation‐associated carcinomas. Sequence analysis for the wild‐type Tsc2 allele in the LOH‐negative carcinomas identified deletions (nonirradiated: 26%; GD19: 21%) and base‐substitution mutations (GD19: 4%). Reduced expression of Tsc2 was also observed in the majority of the LOH‐negative carcinomas. Our results suggest that interstitial chromosomal deletion is a characteristic mutagenic event caused by ionizing radiation, and it may contribute to the assessment of radiation‐induced cancer risk., In this study, we used the Tsc2 heterozygous mutant Eker rat model to investigate the effects of radiation on the development of renal tumors and genomic alterations in those tumors. We found that in renal cancers of Eker rats, the tumor‐suppressor gene Tsc2 was inactivated by multiple mechanisms, including LOH with mitotic recombination or chromosomal deletion, point mutation, deletion and reduced Tsc2 expression. Importantly, our results suggest that interstitial chromosomal deletion is a characteristic mutagenic event caused by ionizing radiation, and it may be a useful indicator for more precise assessment of ionizing radiation‐induced cancer risk.

Malignant pleural mesothelioma (MPM) is a highly aggressive tumor that has a low overall survival; however, no significant treatment advances have been made in the past 15 years. Large-scale molecular studies have identified a poor prognostic subset of MPM linked to the epithelial–mesenchymal transition (EMT) that may contribute toward resistance to chemotherapy, suggesting that EMT could be targeted to treat patients with MPM. Previously, we reported that histone modifiers regulating EMT could be therapeutic targets; therefore, in this study, we investigated whether targeting lysine-specific demethylase 1 (LSD1/KDM1), a histone-modifying enzyme responsible for demethylating histone H3 lysine 4 and lysine 9, could represent a novel therapeutic strategy for MPM. We suppressed LSD1 and investigated the EMT phenotype using EMT marker expression and wound-healing assay; and chemosensitivity using apoptosis assay. We found that suppressing LSD1 induces an epithelial phenotype in sarcomatoid MPM cells, while attenuating the mesenchymal phenotype sensitized MPM cells to cisplatin-induced apoptosis. Subsequent genome-wide identification, comprehensive microarray analysis, and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) to assess genome-wide changes in chromatin accessibility suggested that LSD1 directly regulates milk fat globulin protein E8 (MFGE8), an integrin ligand that is involved in the FAK pathway. Furthermore, we found that LSD1 regulates the mesenchymal phenotype and apoptosis by activating the FAK–AKT–GSK3β pathway via a positive feedback loop involving MFGE8 and Snail expression, thereby leading to cisplatin resistance. Implications: This study suggests that LSD1 regulates the mesenchymal phenotype and apoptosis, and that LSD1 inhibitors could be combined with the cisplatin as a novel therapy for patients with MPM.

Malignant mesothelioma (MM) is an aggressive tumor that typically develops after a long latency following asbestos exposure. Although mechanistic target of rapamycin complex 1 (mTORC1) activation enhances MM cell growth, the mTORC1 inhibitor everolimus has shown limited efficacy in clinical trials of MM patients. We explored the mechanism underlying mTORC1 activation in MM cells and its effects on cell proliferation and progression. Analysis of the expression profiles of 87 MMs from The Cancer Genome Atlas revealed that 40 samples (46%) displayed altered expression of RPTOR (mTORC1 component) and genes immediately upstream that activate mTORC1. Among them, we focused on RHEB and RHEBL1, which encode direct activators of mTORC1. Exogenous RHEBL1 expression enhanced MM cell growth, indicating that RHEB–mTORC1 signaling acts as a pro-oncogenic cascade. We investigated molecules that directly activate RHEBs, identifying SmgGDS as a novel RHEB-binding protein. SmgGDS knockdown reduced mTORC1 activation and inhibited the proliferation of MM cells with mTORC1 activation. Interestingly, SmgGDS displayed high binding affinity with inactive GDP-bound RHEBL1, and its knockdown reduced cytosolic RHEBL1 without affecting its activation. These findings suggest that SmgGDS retains GDP-bound RHEBs in the cytosol, whereas GTP-bound RHEBs are localized on intracellular membranes to promote mTORC1 activation. We revealed a novel role for SmgGDS in the RHEB–mTORC1 pathway and its potential as a therapeutic target in MM with aberrant mTORC1 activation. Implications: Our data showing that SmgGDS regulates RHEB localization to activate mTORC1 indicate that SmgGDS can be used as a new therapeutic target for MM exhibiting mTORC1 activation.

Background Mesothelioma is histologically divided into three subgroups: epithelioid, sarcomatoid, and biphasic types. The epithelioid or sarcomatoid type is morphologically defined by polygonal or spindle-like forms of cells, respectively. The biphasic type consists of both components. It is not yet understood how histological differentiation of mesothelioma is regulated. ERC/mesothelin is expressed in most cases of the epithelioid type, but not in the sarcomatoid type of mesothelioma. Consequently, its expression is well correlated to the histological subtype. We hypothesized that ERC/mesothelin expression influences the histological differentiation of mesothelioma, and tested this hypothesis. Methods We performed studies using the overexpression or knockdown of ERC/mesothelin in mesothelioma cells to examine its effect on cellular morphology, growth kinetics, or migration/invasion activity, in vitro. We then transplanted ERC/mesothelin-overexpressing and control cells into the intraperitoneal space of mice. We examined the effect of ERC/mesothelin overexpression on mouse survival and tumor phenotype. Results In vitro cell culture manipulations of ERC/mesothelin expression did not affect cellular morphology or proliferation, although its overexpression enhanced cellular adhesion and the migration/invasion activity of mesothelioma cells. The survival rate of mice following intraperitoneal transplantation of ERC/mesothelin-overexpressing mesothelioma cells was significantly lower than that of mice with control cells. The histological evaluation of the tumors, however, did not show any morphological difference between two groups, and our hypothesis was not validated. Unexpectedly, both groups (ERC/mesothelin-overexpressing and control) of mesothelioma cells that were morphologically monophasic and spindle-like in vitro differentiated into a biphasic type consisting of polygonal and spindle-like components in the transplanted tumor, irrespective of ERC/mesothelin expression. Conclusions These results suggested that the histological transition of mesothelioma between epithelioid and sarcomatoid types may be reversible and regulated not by ERC/mesothelin, but by other unknown mechanisms.

On July 10, 2016, Alfred G. Knudson, Jr., MD, PhD, a leader in cancer research, died at the age of 93 years. We deeply mourn his loss. Knudson's two‐hit hypothesis, published in 1971, has been fundamental for understanding tumor suppressor genes and familial tumor‐predisposing syndromes. To understand the molecular mechanism of two‐hit‐initiated tumorigenesis, Knudson used an animal model of a dominantly inherited tumor, the Eker rat. From the molecular identification of Tsc2 germline mutations, the Eker rat became a model for tuberous sclerosis complex (TSC), a familial tumor‐predisposing syndrome. Animal models, including the fly, have greatly contributed to TSC research. Because the product of the TSC2/Tsc2 gene (tuberin) together with hamartin, the product of another TSC gene (TSC1/Tsc1), suppresses mammalian/mechanistic target of rapamycin complex 1 (mTORC1), rapalogs have been used as therapeutic drugs for TSC. Although significant activity of these drugs has been reported, there are still problems such as recurrence of residual tumors and adverse effects. Recent studies indicate that there are mTORC1‐independent signaling pathways downstream of hamartin/tuberin, which may represent new therapeutic targets. The establishment of cellular models, such as pluripotent stem cells with TSC2/Tsc2 gene mutations, will facilitate the understanding of new aspects of TSC pathogenesis and the development of novel treatment options. In this review, we look back at the history of Knudson and animal models of TSC and introduce recent progress in TSC research.

Human breast carcinoma‐associated fibroblasts (CAFs) increasingly acquire both transforming growth factor‐β (TGF‐β) and stromal cell‐derived factor‐1 (SDF‐1) signaling in an autocrine fashion during tumor progression. Such signaling mediates activated myofibroblastic and tumor‐promoting properties in these fibroblasts. CD26/dipeptidyl peptidase‐4 is a serine protease that cleaves various chemokines including SDF‐1. Stromal CD26 expression is reportedly undetectable in human skin squamous cell carcinomas. However, whether stromal CD26 expression is also downregulated in human breast cancers and which stromal cells potentially lack CD26 expression remain elusive. To answer these questions, sections prepared from 239 human breast carcinomas were stained with antibodies against CD26 and α‐smooth muscle actin (α‐SMA), a marker for activated myofibroblasts. We found that tumor‐associated stroma involving α‐SMA‐positive myofibroblasts stained negative or negligible for CD26 in 118 out of 193 (61.1%) tumors, whereas noncancerous stromal regions of the breast showed considerable staining for CD26. This decreased stromal CD26 staining in tumors also tends to be associated with poor outcomes for breast cancer patients. Moreover, we demonstrated that CD26 staining is attenuated on stromal myofibroblasts in human breast cancers. Consistently, CD26 expression is significantly downregulated in cultured CAF myofibroblasts extracted from human breast carcinomas as compared to control human mammary fibroblasts. Inhibition of TGF‐β or SDF‐1 signaling in CAFs by shRNA clearly upregulated the CD26 expression. Taken together, these findings indicate that CD26 expression is attenuated by TGF‐β‐ and SDF‐1‐autocrine signaling on stromal myofibroblasts in human mammary carcinomas, and that decreased stromal CD26 expression has potential as a prognostic marker.

Primarily caused by exposure to asbestos, mesothelioma is a typical occupational disease. The latency of mesothelioma is as long as 20‐40 years, and the cancer initially progresses mainly along the surfaces of pleura or peritoneum without forming masses. As symptoms do not develop until late stages, it has been challenging to diagnose this disease in its early stages and to carry out complete surgical removal. In responding to Japan's asbestos crisis in the mid‐2000s, we have developed and improved ERC/MSLN‐based serum and radiological markers and pioneered the use of an N‐ERC ELISA kit for screening populations at risk for asbestos exposure. In the present article, we review our research toward early diagnosis of asbestos‐related mesothelioma before symptoms develop and share our clinical experience of screening, diagnosing and monitoring of this disease. This paper is dedicated to the author (Dr Okio Hino) to commemorate the honor bestowed upon him as the recipient of the Mataro Nagayo Prize in 2018.

Introduction: There remains a considerable need for the development of new, simple methods for assessing methylation of cell-free DNA obtained from liquid biopsies. In particular, methods that can achieve highly-sensitive quantitative analysis are needed to enable estimation of tumor burden, invasiveness and recurrence. While standard methylation-sensitive high resolution melt (MS-HRM) analysis methods allow for semi-quantitative assessment of DNA methylation, achieving sufficient sensitivity and accuracy to enable reliable detection of rare circulating tumor DNA (ctDNA) in a large background of predominantly healthy cfDNA remains challenging. We developed a novel method that drastically improves the analytical sensitivity of HRM analysis in order to quantify epiallelic fractions as low as 0.001%. This method was named HiQASP (Highly Quantitative Allele Specific PCR). We demonstrate use of HiQASP for ultra-high-sensitive and quantitative methylation assessment of the promoter region of SEPT9, which is currently used in colorectal cancer screening kits. Here, we utilize this method to assess SEPT9 methylation in cfDNA derived from with liquid biopsies of colorectal cancer patients. Methods: All human blood samples were obtained with patient's consent and relevant IRB approval. The plasma specimens were separated with twice centrifugation and cfDNA purified with Qiagen's QIAamp Circulating Nucleic Acid Kit. Bisulfite conversion was performed using Zymo EZ DNA Methylation-Lightning kit according to the manufacturer's instructions. Plasma DNA concentrations were calculated using DX-11Fx (DeNovix) with QuantiFluor (Promega). Analytic specificities and sample epiallelic quantification were determined using synthetic oligonucleotide standards for the bisulfite-converted sequence of methylated and unmethylated SEPT9 were obtained from IDT and GenScript, respectively. Validation of the SEPT9 HiQASP assay was performed using serial dilutions of synthetic oligonucleotides. EpiTaq HS (TaKaRa) and EvaGreen (BioTium) were used to amplify and detect the PCR products, respectively. The equipment QuantStudio 3 (ThermoFisher) was used to amplify and execute HRM analysis. Results: Custom HiQASP primers were designed to maximize assay analytical sensitivity and specificity for methylation analysis at the SEPT9 locus. Overall, the SEPT9 HiQASP assay achieved an analytical sensitivity of 0.0005% for both bisulfite-converted unmethylated and methylated synthetic oligonucleotide targets. The entire assay could be performed in only 45 minutes. The potential clinical utility of the assay was also demonstrated using cfDNA derived from of a plasma sample obtained from a colorectal cancer patient. HiQASP analysis indicated the percentage of methylated SEPT9 in this specimen to be 3.8% yielding a total copy concentration of 35 copies of methylated SEPT9 per ml of plasma. Conclusion: HiQASP is a highly-sensitive locus-specific assay for facile, rapid and low-cost quantitative assessment of methylated DNA in challenging specimens such as liquid biopsies. Citation Format: Sachio Nomura, Toshiyuki Kobayashi, Kiichi Sugimoto, Masami Arai, Thomas R. Pisanic, Hirotaka Momose, Kazuhiro Sakamoto, Okio Hino. A novel method for highly sensitive, facile and inexpensive quantitative assessment of aberrant DNA methylation in liquid biopsies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1973.

Despite current advances in human colorectal cancer (CRC) treatment, few radical therapies are effective for the late stages of CRC. To overcome this clinical challenge, tumor xenograft mouse models using long-established human carcinoma cell lines and many transgenic mouse models with tumors have been developed as preclinical models. They partially mimic the features of human carcinomas, but often fail to recapitulate the key aspects of human malignancies including invasion and metastasis. Thus, alternative models that better represent the malignant progression in human CRC have long been awaited. We herein show generation of patient-derived tumor xenografts (PDXs) by subcutaneous implantation of small CRC fragments surgically dissected from a patient. The colon PDXs develop and histopathologically resemble the CRC in the patient. However, few spontaneous micrometastases are detectable in conventional cross-sections of affected distant organs in the PDX model. To facilitate the detection of metastatic dissemination into distant organs, we extracted the tumor organoid cells from the colon PDXs in culture and infected them with GFP lentivirus prior to injection into highly immunodeficient NOD/Shi-scid IL2Rγ(null) (NOG) mice. Orthotopically injected PDX-derived CRC organoid cells consistently form primary tumors positive for GFP in recipient mice. Moreover, spontaneously developing micrometastatic colonies expressing GFP are notably detected in the lungs of these mice by fluorescence microscopy. Moreover, intrasplenic injection of CRC organoids frequently produces hepatic colonization. Taken together, these findings indicate GFP-labelled PDX-derived CRC organoid cells to be visually detectable during a multistep process termed the invasion-metastasis cascade. The described protocols include the establishment of PDXs of human CRC and 3D culture of the corresponding CRC organoid cells transduced by GFP lentiviral particles.

The model animal of renal cell carcinoma (RCC), the Eker rat, has a germline mutation in the tuberous sclerosis 2 (Tsc2) gene. Heterozygous mutants develop RCCs by second hit in the wild-type Tsc2 allele, whereas homozygous mutants are embryonic lethal. In the present study, a new cell differentiation model was developed to study the mechanism of Tsc2 mutation-associated pathogenesis by generating Tsc2-deficient embryonic stem cells (ESCs) from Eker rats. Tsc2+/+, Tsc2+/- and Tsc2-/- ESCs were all capable of generating three germ layers: mesoderm, ectoderm, and endoderm. Interestingly, epithelial tumor-like abnormal ductal structures were reproducibly observed in Tsc2-/- teratomas from different ESC lines. Immunohistochemical analysis revealed that mammalian target of rapamycin complex 1 (mTORC1) signaling was activated in abnormal ducts of Tsc2-/- teratomas, on the basis of positive staining for p-S6 and p-4EBP1. In these abnormal ducts, expression levels of epithelial markers (i.e., megalin and cubilin) and the cytoplasmic localization of E-cadherin and β-catenin were similar to those in Eker rat RCCs. Moreover, a transcription factor regulated by mTORC1, named TFE3, was located in the nuclei of abnormal ducts and Eker rat RCCs. As a negative regulator of ESC differentiation, TFE3 may result in tissue-specific differentiation defects related to tumorigenesis in Eker rats and Tsc2-/- teratomas. The present study suggests that ESCs derived from Eker rats constitute a novel experimental tool with which to analyze differentiation defects and cell-type specific pathogenesis associated with Tsc2 deficiency.

Pleural mesothelioma is an aggressive tumor, commonly caused by exposure to asbestos. The prognosis of mesothelioma remains disappointing despite multimodal treatment. We reported previously that N-ERC/mesothelin could be a useful biomarker for the early diagnosis of pleural mesothelioma and developed an enzyme-linked immunosorbent assay (ELISA) system for its detection. However, the reproducibility of our previous 7–16 ELISA system has been revealed to be unsatisfactory. To measure N-ERC/mesothelin more precisely, we developed a new 7–20 ELISA system. The subjects of this study were patients who were referred to our department with suspected pleural mesothelioma. The current study demonstrated that the newly established 7–20 ELISA system improved the sensitivity and specificity for diagnosing pleural mesothelioma compared with the previous system. Moreover, the 7–20 ELISA system showed better reproducibility and displayed the tendency of both higher sensitivity and higher specificity in plasma than in serum. Particularly for the epithelioid type, the area under the curve (AUC) and the diagnostic accuracy of N-ERC/mesothelin were excellent; the AUC was 0.91, the sensitivity was 0.95, and the specificity was 0.76 in plasma. In conclusion, assessment of N-ERC/mesothelin with our newly established 7–20 ELISA system is clinically useful for the precise diagnosis of pleural mesothelioma.

Gastric cancer is the second leading cause of cancer mortality in the world. It is important to develop biomarkers for detecting new cancers at an early stage and for treating them early during recurrence in order to guide optimal treatment. Fatty acid synthase (FAS) is highly expressed in numerous human cancers and thus could potentially serve as such a biomarker, but the potential utility of measuring FAS for detecting gastric cancer has not been previously investigated. The aim of the present study was to provide a preliminary assessment of serum FAS as a marker of gastric carcinoma. The study included 47 patients with gastric cancer and 150 healthy subjects. Blood samples were collected from each cancer patient prior to treatment. Serum FAS levels were measured by ELISA and compared across the two groups of patients. Significantly higher levels of serum FAS were found in the gastric cancer patients [95% confidence interval (CI), 30.37–52.46] compared with the healthy controls (95% CI, 1.331–2.131), with elevated levels even in patients with early-stage tumors. These results indicate that measuring serum FAS levels has strong potential to provide a biomarker for the detection of gastric cancer, with high sensitivity and specificity.

This study highlights the cellular and molecular mechanisms by which stromal fibroblasts enable human breast cancer cells to form tumor cell clusters and acquire highly invasive and metastatic traits., Emerging evidence supports the hypothesis that multicellular tumor clusters invade and seed metastasis. However, whether tumor-associated stroma induces epithelial–mesenchymal plasticity in tumor cell clusters, to promote invasion and metastasis, remains unknown. We demonstrate herein that carcinoma-associated fibroblasts (CAFs) frequently present in tumor stroma drive the formation of tumor cell clusters composed of two distinct cancer cell populations, one in a highly epithelial (E-cadherinhiZEB1lo/neg: Ehi) state and another in a hybrid epithelial/mesenchymal (E-cadherinloZEB1hi: E/M) state. The Ehi cells highly express oncogenic cell–cell adhesion molecules, such as carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) and CEACAM6 that associate with E-cadherin, resulting in increased tumor cell cluster formation and metastatic seeding. The E/M cells also retain associations with Ehi cells, which follow the E/M cells leading to collective invasion. CAF-produced stromal cell-derived factor 1 and transforming growth factor-β confer the Ehi and E/M states as well as invasive and metastatic traits via Src activation in apposed human breast tumor cells. Taken together, these findings indicate that invasive and metastatic tumor cell clusters are induced by CAFs via epithelial–mesenchymal plasticity.

The worldwide incidence of the highly aggressive tumor mesothelioma is expected to increase. Mesothelioma is classified into three main histological subtypes: epithelioid, sarcomatoid and biphasic. Although the pathological diagnostic markers for epithelioid are established, to date no adequate marker for sarcomatoid mesothelioma has been found. Thus, a reliable diagnostic marker of sarcomatoid mesothelioma is necessary. In this study, to identify an unknown protein with 120 kDa expressed only in the mesothelioma cell line 211H, we conducted proteomic analysis and found five candidate proteins. One such protein, AHNAK, was highly expressed in all seven mesothelioma cell lines (211H, H28, H226, H2052, H2452, MESO1 and MESO4), but not in the mesothelial cell line MeT-5A by RT-PCR and immunofluorescence staining. Furthermore, we confirmed high AHNAK expression not only in xenografts but also in human mesothelioma specimens including sarcomatoid, epithelioid and biphasic mesothelioma using immunohistochemical staining. These findings suggest that AHNAK has the potential to be a new marker for detecting mesothelioma. Since AHNAK is involved in cell migration and invasion in other metastatic tumor cells, we conducted migration and invasion assays in mesothelioma cell lines. The number of migrating cells in six of seven mesothelioma cell lines and the number of invading cells in all seven cell lines were significantly increased compared with those in MeT-5A. Knockdown of AHNAK significantly reduced the cell migration and invasion ability in all seven mesothelioma cell lines. These results support further clinical evaluation of the association of AHNAK and metastasis in mesothelioma.

ADAM28, a disintegrin and metalloproteinase 28, is overexpressed by carcinoma cells with direct correlations with carcinoma cell proliferation and progression in human lung and breast carcinomas. However, the molecular mechanisms of ADAM28 gene expression in carcinoma cells remain elusive. Herein, we investigated the expression of ADAM28 in Madin-Darby canine kidney epithelial cells transformed by oncogenes, including v- src , LMP1 , ErbB2 , Ha -Ras , and c- Fos , and found that v- src transformants selectively induce ADAM28. Implantation of the v-src transformants showed a progressively growing tumor, which was significantly suppressed by local injections of anti-ADAM28 antibody. ADAM28 expression in v- src transformants was partially inhibited by treatment with inhibitors to Src kinase, mitogen-activated protein kinase kinase (MEK), phosphatidylinositol 3-kinase (PI3K), or mammalian target of rapamycin, and abrogated by v-Src kinase inhibitor, radicicol, or a mixture of MEK and PI3K inhibitors. Human carcinoma cell lines of the lung, breast, ovary, kidney, and colon showed ADAM28 expression, which was correlated with phosphorylation of c-Src and suppressed by the inhibitors in a similar way to v- src transformants. IHC of the human tumor tissues demonstrated co-expression of ADAM28 and phosphorylated Src in neoplastic cells of the breast, lung, and colon carcinomas and some adenomas of the colon, but not in nonneoplastic colon mucosa. Our data provide, to the best of our knowledge, the first evidence that Src is an inducer of ADAM28 gene expression through the MEK/extracellular signal–regulated kinase and PI3K/mammalian target of rapamycin pathways.