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Acinar cell carcinoma (ACC) of the pancreas is a malignant tumor of the exocrine cell lineage with a poor prognosis. Due to its rare incidence and technical difficulties, few authentic human cell lines are currently available, hampering detailed investigations of ACC. Therefore, we applied the organoid culture technique to various types of specimens, such as bile, biopsy, and resected tumor, obtained from a single ACC patient. Despite the initial propagation, none of these organoids achieved long-term proliferation or tolerated cryopreservation, confirming the challenging nature of establishing ACC cell lines. Nevertheless, the biopsy-derived early passage organoid developed subcutaneous tumors in immunodeficient mice. The xenograft tumor histologically resembled the original tumor and gave rise to infinitely propagating organoids with solid features and high levels of trypsin secretion. Moreover, the organoid stained positive for carboxylic ester hydrolase, a specific ACC marker, but negative for the duct cell marker CD133 and the endocrine lineage marker synaptophysin. Hence, we concluded the derivation of a novel ACC cell line of the pure exocrine lineage, designated HS-1. Genomic analysis revealed extensive copy number alterations and mutations in EP400 in the original tumor, which were enriched in primary organoids. HS-1 displayed homozygous deletion of CDKN2A, which might underlie xenograft formation from organoids. Although resistant to standard cytotoxic agents, the cell line was highly sensitive to the proteasome inhibitor bortezomib, as revealed by an in vitro drug screen and in vivo validation. In summary, we document a novel ACC cell line, which could be useful for ACC studies in the future.

Cervical cancer remains a major threat to women's health, especially in countries with limited medical resources, and new drugs are needed to improve patient survival and minimize adverse effects. Here, we examine the effects of a triphenylphosphonium (TPP)-conjugated pyrrole-imidazole polyamide (CCC-h1005) targeting the common homoplasmic mitochondrial DNA (mtDNA) cancer risk variant (ATP6 8860AG) on the survival of cervical cancer cell lines, cisplatin-resistant HeLa cells and patient-derived cervical clear cell carcinoma cells as models of cervical cancer treatment. We found that CCC-h1005 induced death in these cells and suppressed the growth of xenografted HeLa tumors with no severe adverse effects. These results suggest that PIP-TPP designed to target mtDNA cancer risk variants can be used to treat many cervical cancers harboring high copies of the target variant, providing a foundation for clinical trials of this class of molecules for treating cervical cancer and other types of cancers.

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer-related deaths worldwide. Chemotherapies against gastric cancer often fail, with cancer recurrence due potentially to the persistence of cancer stem cells. This unique subpopulation of cells in tumors possesses the ability to self-renew and dedifferentiate. These cancer stem cells are critical for initiation, maintenance, metastasis, and relapse of cancers; however, the molecular mechanisms supporting cancer stemness remain largely unknown. Increased kinase and decreased phosphatase activity are hallmarks of oncogenic signaling. Protein phosphatase 2A (PP2A) functions as a tumor-suppressor enzyme, and elevated levels of SET/I2PP2A, an endogenous PP2A protein inhibitor, are correlated with poor prognosis of several human cancers. Here, it was determined that SET expression was elevated in tumor tissue in a gastric cancer mouse model system, and SET expression was positively correlated with poor survival of human gastric cancer patients. Mechanistically, SET knockdown decreased E2F1 levels and suppressed the stemness of cancer cell lines. Immunoprecipitations show SET associated with the PP2A–B56 complex, and the B56 subunit interacted with the E2F1 transcription factor. Treatment of gastric cancer cells with the SET-targeting drug OP449 increased PP2A activity, decreased E2F1 protein levels, and suppressed stemness of cancer cells. These data indicate that a SET/PP2A/E2F1 axis regulates cancer cell stemness and is a potential target for gastric cancer therapy.Implications: This study highlights the oncogenic role of SET/I2PP2A in gastric cancer and suggests that SET maintains cancer cell stemness by suppressing PP2A activity and stabilizing E2F1. Mol Cancer Res; 16(3); 554–63. ©2018 AACR.

This file contains detailed material and methods, and supplemental data related with Fig. 1g, Fig. 2a, b, Fig. 3c, d, Fig. 4a, b, c, Fig. 5c

Cervical clear cell carcinoma (CCCC) is rare. This report describes the case of CCCC with a serous component. A 22-year-old woman presented with vaginal bleeding. A cervical tumor was discovered: pelvic magnetic resonance imaging revealed a tumor measuring 46 mm. Radical hysterectomy was performed based on the diagnosis of stage IB2 cervical cancer. After histological examination of the specimen revealed a coexisting invasive clear cell carcinoma (95%) and serous carcinoma (5%), five cycles of nedaplatin and irinotecan therapy were administered as postoperative adjuvant chemotherapy. Local recurrence in the vaginal vault was observed at 7 months after surgery. Radiation therapy and chemotherapy were administered. The patient is alive without evidence of recurrence at 26 months after surgery.

Genetically engineered mice (GEM) are the gold standard for cancer modeling. However, strict recapitulation of stepwise carcinogenesis from a single tumor-initiating epithelial cell among genetically intact cells in adults is not feasible with the currently available techniques using GEM. In previous studies, we partially overcame this challenge by physically isolating organs from adult animals, followed by genetic engineering in organoids and subcutaneous inoculation in nude mice. Despite the establishment of suitable ex vivo carcinogenesis models for diverse tissues, tumor development remained ectopic and occurred under immunodeficient conditions. Further refinement was, therefore, necessary to establish ideal models. Given the poor prognosis and few models owing to the lack of gall bladder (GB)-specific Cre strain, we assumed that the development of authentic models would considerably benefit GB cancer research. Here, we established a novel model using GB organoids with mutant Kras and Trp53 loss generated in vitro by lentiviral Cre transduction and CRISPR/Cas9 gene editing, respectively. Organoid-derived subcutaneous tumor fragments were sutured to the outer surface of the GB in syngeneic mice, which developed orthotopic tumors that resembled human GB cancer in histological and transcriptional features. This model revealed the infiltration of similar subsets of immune cells in both subcutaneous and orthotopic tumors, confirming the appropriate immune environment during carcinogenesis. In addition, we accurately validated the in vivo efficacy of gemcitabine, a common therapeutic agent for GB cancer, in large cohorts. Taken together, this model may serve as a promising avatar of patients with GB cancer in drug discovery and precision medicine.

Recently, we introduced an organoid-based chemical carcinogenesis model using mouse normal tissue-derived organoids. In the present review article, the histopathological and immunohistochemical characteristics of mouse normal tissue-derived organoids and tumors derived from these organoids after their

KRAS, an oncogene, is frequently activated by mutations in many cancers. Kras-driven adenocarcinoma development in the lung, pancreas, and biliary tract has been extensively studied using gene targeting in mice. By taking the organoid- and allograft-based genetic approach to these organs, essentially the same results as in vivo models were obtained in terms of tumor development. To verify the applicability of this approach to other organs, we investigated whether the combination of Kras activation and Pten inactivation, which gives rise to endometrial tumors in mice, could transform murine endometrial organoids in the subcutis of immunodeficient mice. We found that in KrasG12D-expressing endometrial organoids, Pten knockdown did not confer tumorigenicity, but Cdkn2a knockdown or Trp53 deletion led to the development of carcinosarcoma (CS), a rare, aggressive tumor comprising both carcinoma and sarcoma. Although they originated from epithelial cells, some CS cells expressed both epithelial and mesenchymal markers. Upon inoculation in immunodeficient mice, tumor-derived round organoids developed carcinoma or CS, whereas spindle-shaped organoids formed monophasic sarcoma only, suggesting an irreversible epithelial-mesenchymal transition during the transformation of endometrial cells and progression. As commonly observed in mutant Kras-driven tumors, the deletion of the wild-type Kras allele was identified in most induced tumors, whereas some epithelial cells in CS-derived organoids were unexpectedly negative for KrasG12D. Collectively, we showed that the oncogenic potential of KrasG12D and the histological features of derived tumors are context-dependent and varies according to the organ type and experimental settings. Our findings provide novel insights into the mechanisms underlying tissue-specific Kras-driven tumorigenesis.

Cervical clear cell carcinoma (cCCC) constitutes an extremely rare subtype of cervical cancer. Consequently, its pathogenesis remains largely unknown, with no cell lines established from primary tumors. Here, we report the first establishment of cCCC organoids, from biopsy samples of a 23‐year‐old patient diagnosed with cCCC. By applying a protocol that we recently optimized for gynecological tumors, we were able to propagate a patient‐derived cell line (PDC) for more than 6 months as organoids. This PDC tolerated cryopreservation and proliferated either as spheroids or adherent cells, and developed xenografts in immunodeficient mice, ensuring robust utility as a cell line. Intriguingly, the resected tumor focally contained serous carcinoma (SC) in a tiny protruding lesion. Both organoids and derivative xenografts resembled the CCC component of the original tumor in histology, immunostaining profile, and genome‐wide copy number changes, including focal gain of MET. Genomic analysis revealed that both organoids and the CCC component harbored only a few mutations, of which 2 mutations were shared in common. In contrast, the SC component showed a mutator‐phenotype and prominent genome instability along with biallelic inactivation of TP53, but none of them were found in organoids or the CCC component. The PDC proved sensitive to major chemotherapeutic agents and MET inhibitors. These observations clearly indicated that the PDC, designated as YMC7, can be used as a novel cCCC cell line and provide novel insights into the pathogenesis of mixed cervical adenocarcinoma. As a valuable resource for rare cancer, it will likely contribute to investigations in many fields.

The organoid culture technique has been recently applied to modeling carcinogenesis in several organs. To further explore its potential and gain novel insights into tumorigenesis, we here investigated whether pancreatic ductal adenocarcinoma (PDA) could be generated as subcutaneous tumors in immunocompromised nude mice, by genetic engineering of normal organoids. As expected, acute induction of KrasG12Din vitro occasionally led to development of tiny nodules compatible with early lesions known as pancreatic intraepithelial neoplasia (PanIN). KrasG12D-expressing cells were enriched after inoculation in the subcutis, yet proved rather declined during culture, suggesting that its advantage might depend on surrounding environments. Depletion of growth factors or concurrent Trp53 deletion resulted in its robust enrichment, invariably leading to development of PanIN or large high-grade adenocarcinoma, respectively, consistent with in vivo mouse studies for the same genotype. Progression from PanIN was also recapitulated by subsequent knockdown of common tumor suppressors, whereas the impact of Tgfbr2 deletion was only partially recapitulated, illustrating genotype-dependent requirement of the pancreatic niche for tumorigenesis. Intriguingly, analysis of tumor-derived organoids revealed that KrasG12D-expressing cells with spontaneous deletion of wild-type Kras were positively selected and exhibited an aging-related mutation signature in nude mice, mirroring the pathogenesis of human PDA, and that the sphere-forming potential and orthotopic tumorigenicity in syngenic mice were significantly augmented. These observations highlighted the relevance of the subcutis of nude mice in promoting PDA development despite its ectopic nature. Taken together, pancreatic carcinogenesis could be considerably recapitulated with organoids, which would probably serve as a novel disease model.

Genetically engineered mice have been the gold standard in modeling tumor development. Recent studies have demonstrated that genetically engineered organoids can develop subcutaneous tumors in immunocompromised mice, at least for organs that prefer predominant driver mutations for tumorigenesis. To further substantiate this concept, the fallopian tube (FT), a major cell of origin of ovarian high-grade serous carcinoma (HGSC), which almost invariably carries TP53 mutations, was investigated for p53 inactivation-driven tumorigenesis. Murine FT organoids subjected to lentiviral Cre-mediated Trp53 deletion did not develop tumors. However, subsequent suppression of Pten and simultaneous induction of mutant Pik3ca led to the development of carcinoma in situ and HGSC-like tumors, respectively, whereas concurrent deletion of Apc resulted in the development of benign cysts, mirroring frequent activation of the PI3K/AKT axis and the marginal impact of Wnt pathway activation in HGSC. Consistent with the frequent activation of the RAS pathway in HGSC, mutant Kras cooperated with Trp53 deletion for the development of tumors, which unexpectedly contained sarcoma cells in addition to carcinoma cells, despite the epithelial origin of the inoculated organoids. This finding is in sharp contrast with the exclusive adenocarcinoma development from gastrointestinal organoids with the same genotype reported in previous studies, suggesting a tissue-specific epithelial-mesenchymal transition program. In tumor-derived organoids, the Cre-mediated recombination rate reached 100% for Trp53 but not for the other genes, highlighting the advantage of p53 inactivation in FT tumorigenesis. The Trp53 wildtype FT organoids expressing the mutant Kras developed sarcoma and carcinoma upon Cdkn2a suppression and Tgfbr2 deletion, respectively, revealing novel pro-tumorigenic genetic cooperation and critical roles of TGF-β signaling for epithelial-mesenchymal transition in FT-derived tumorigenesis. Collectively, the organoid-based approach represents a shortcut to tumorigenesis and provides novel insights into the relationships among genotype, cell type, and tumor phenotype underlying tumorigenesis. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Simple Summary Biliary tract cancer (BTC) is often refractory to conventional therapeutics and is difficult to diagnose in the early stages. In addition, the pathogenesis of BTC is not fully understood, despite recent advances in cancer genome analysis. To address these issues, the development of fine disease models is critical for BTC. Although still limited in number, there are various platforms for genetic models of BTC owing to newly emerging technology. Among these, implantation-based models have recently drawn attention for their convenience, flexibility, and scalability. To highlight the relevance of this approach, we comprehensively summarize the advantages and disadvantages of BTC models developed using diverse approaches. Currently available research data on intra- and extrahepatic cholangiocarcinoma and gallbladder carcinoma are presented in this review. This information will likely help in selecting the optimal models for various applications and develop novel innovative models based on these technologies. Abstract Epithelial cells in the biliary system can develop refractory types of cancers, which are often associated with inflammation caused by viruses, parasites, stones, and chemicals. Genomic studies have revealed recurrent genetic changes and deregulated signaling pathways in biliary tract cancer (BTC). The causal roles have been at least partly clarified using various genetically engineered mice. Technical advances in Cre-LoxP technology, together with hydrodynamic tail injection, CRISPR/Cas9 technology, in vivo electroporation, and organoid culture have enabled more precise modeling of BTC. Organoid-based genetic modeling, combined with implantation in mice, has recently drawn attention as a means to accelerate the development of BTC models. Although each model may not perfectly mimic the disease, they can complement one another, or two different approaches can be integrated to establish a novel model. In addition, a comparison of the outcomes among these models with the same genotype provides mechanistic insights into the interplay between genetic alterations and the microenvironment in the pathogenesis of BTCs. Here, we review the current status of genetic models of BTCs in mice to provide information that facilitates the wise selection of models and to inform the future development of ideal disease models.

Ovarian clear cell carcinoma (OCCC) is an aggressive ovarian cancer with a higher frequency in Japan and often becomes chemorefractory disease. Reliable genetic diagnosis is essential to affirm the success of precision medicine for OCCC treatment. The aim of this study is, therefore, to identify novel mutations in OCCCs and develop a feasible clinical next generation sequencing (NGS) approach using formalin-fixed paraffin-embedded (FFPE) rather than preferable but not always available fresh frozen (FF) samples.We optimized and evaluated exome analyses of 409 cancer-related genes using FFPE and FF DNA and analyzed NGS data to identify somatic mutations in Japanese OCCCs.Sufficient and good quality DNAs from FFPE samples were extracted from 18 (FIGO Stage I: 12) out of 29 pairs of matched normal and OCCC for NGS (63%). The fine quality of extracted DNAs depended on the length of storage period (2years storage). We also identified 45 somatic mutations in 34 genes including unreported variants from those FFPE DNA, in which somatic mutations in the PIK3CA gene was the most common (28%) as previously reported. Seven genes (PIK3CA, ARID1A, CTNNB1, CSMD3, LPHN3, LRP1B, and TP53) were mutated in at least two independent OCCCs. FF samples from 3 out of those 18 OCCCs were available and 13 out of 14 FFPE somatic mutations were confirmed.We successfully identified novel genetic alterations in Japanese OCCCs and demonstrated a feasible clinical diagnostic procedure using targeted NGS for OCCC FFPE samples.

Animal carcinogenesis models induced by environmental chemicals have been widely used for basic and applied cancer research. However, establishment of in vitro or ex vivo models is essential for molecular mechanistic elucidation of early events in carcinogenesis, leading to clarification of the total mode of action. In the present study, to establish an organoid-based chemical carcinogenesis model, mouse organoids were treated in vitro with 4 genotoxic chemicals, e.g. ethyl methanesulfonate (EMS), acrylamide (AA), diethylnitrosamine (DEN) and 7,12-dimethylbenz[a]anthracene (DMBA) to examine their tumorigenicity after injection to nude mice. The four chemicals were reported to induce lung, liver or mammary carcinomas in mouse models. DMBA-treated mammary tissue-derived organoids with Trp53 heterozygous knockout exhibited tumorigenicity, but not those with wild-type Trp53, reflecting previous reports of corresponding animal models. Treatment of lung organoids with or without Trp53 knockout with EMS or AA resulted in carcinogenic histopathological characteristics, and the activation of oncogenic kinases was demonstrated in the nodules from the nude mouse subcutis. DEN-treated liver (biliary tract) organoids also had an increased number of similar changes. In conclusion, an ex vivo model for chemical carcinogenesis was established using normal mouse tissue-derived organoids. This model will be applied to detect early molecular events, leading to clarification of the mode of action of chemical carcinogenesis.

Ovarian cancer (OC) is one of the leading causes of female cancer death. Recent studies have documented its extensive variations as a disease entity, in terms of cell or tissue of origin, pre-cancerous lesions, common mutations, and therapeutic responses, leading to the notion that OC is a generic term referring to a whole range of different cancer subtypes. Despite such heterogeneity, OC treatment is stereotypic; aggressive surgery followed by conventional chemotherapy could result in chemo-resistant diseases. Whereas molecular-targeted therapies will become shortly available for a subset of OC, there still remain many patients without effective drugs, requiring development of groundbreaking therapeutic agents. In preclinical studies for drug discovery, cancer cell lines used to be the gold standard, but now this has declined due to frequent failure in predicting therapeutic responses in patients. In this regard, patient-derived cells and tumors are gaining more attention in precise and physiological modeling of in situ tumors, which could also pave the way to implementation of precision medicine. In this article, we comprehensively overviewed the current status of various platforms for patient-derived OC models. We highly appreciate the potentials of organoid culture in achieving high success rate and retaining tumor heterogeneity.

Remarkable upregulation of the NRF2 (NFE2L2)-related transcription factor NRF3 (NFE2L3) in several cancer tissues and its correlation with poor prognosis strongly suggest the physiological function of NRF3 in tumors. Indeed, we had recently uncovered the function of NRF3, which promotes cancer cell proliferation by p53 degradation via the 20S proteasome. Nevertheless, the molecular mechanism underlying the induction of NRF3 gene expression in cancer cells is highly elusive. We herein describe that NRF3 upregulation is induced by the β-catenin/TCF4 complex in colon cancer cells. We first confirmed high NRF3 mRNA expression in human colon cancer specimens. The genome database indicated that the human NRF3 gene possesses a species-conserved WRE sequence (TCF/LEF consensus element), implying that the β-catenin/TCF complex activates NRF3 expression in colon cancer. Consistently, we observed that the β-catenin/TCF4 complex mediates NRF3 expression by binding directly to the WRE site. Furthermore, inducing NRF3 activates cell proliferation and the expression of the glucose transporter GLUT1. The existence of the β-catenin/TCF4-NRF3 axis was also validated in the intestine and organoids of Apc-deficient mice. Finally, the positive correlation between NRF3 and β-catenin target gene expression strongly supports our conclusion. Our findings clearly demonstrate that NRF3 induction in cancer cells is controlled by the Wnt/β-catenin pathway.

Mutations in SPINT2 encoding the epithelial serine protease inhibitor hepatocyte growth factor activator inhibitor-2 (HAI-2) are associated with congenital tufting enteropathy. However, the functions of HAI-2 in vivo are poorly understood. Here we used tamoxifen-induced Cre-LoxP recombination in mice to ablate Spint2. Mice lacking Spint2 died within 6 days after initiating tamoxifen treatment and showed severe epithelial damage in the whole intestinal tracts, and, to a lesser extent, the extrahepatic bile duct. The intestinal epithelium showed enhanced exfoliation, villous atrophy, enterocyte tufts and elongated crypts. Organoid crypt culture indicated that Spint2 ablation induced Epcam cleavage with decreased claudin-7 levels and resulted in organoid rupture. These organoid changes could be rescued by addition of serine protease inhibitors aprotinin, camostat mesilate and matriptase-selective α-ketobenzothiazole as well as by co-deletion of Prss8, encoding the serine protease prostasin. These results indicate that HAI-2 is an essential cellular inhibitor for maintaining intestinal epithelium architecture., Makiko Kawaguchi et al. developed an inducible Spint2 knockout mouse model which exhibited extensive damage to the intestinal epithelium and resulted in death six days after tamoxifen-induced gene ablation. The extreme phenotype observed in this inducible line suggests an important role for Spint2 in maintenance of healthy intestinal epithelium.

Inactivation of the Adenomatous polyposis coli (APC) gene is an initiating and the most relevant event in most sporadic cases of colorectal cancer, providing a rationale for using Apc-mutant mice as the disease model. Whereas carcinogenesis has been observed only at the organism level, the recent development of the organoid culture technique has enabled long-term propagation of intestinal stem cells in a physiological setting, raising the possibility that organoids could serve as an alternative platform for modeling colon carcinogenesis. Indeed, it is demonstrated in the present study that lentivirus-based RNAi-mediated knockdown of Apc in intestinal organoids gave rise to subcutaneous tumors upon inoculation in immunodeficient mice. Reconstitution of common genetic aberrations in organoids resulted in development of various lesions, ranging from aberrant crypt foci to full-blown cancer, recapitulating multi-step colorectal tumorigenesis. Due to its simplicity and utility, similar organoid-based approaches have been applied to both murine and human cells in many investigations, to gain mechanistic insight into tumorigenesis, to validate putative tumor suppressor genes or oncogenes, and to establish preclinical models for drug discovery. In this review article, we provide a multifaceted overview of these types of approaches that will likely accelerate and advance research on colon cancer.

The metaplastic epithelium of the transformation zone (TZ) including the squamocolumnar junction (SCJ) of the uterine cervix is a prime target of human papilloma virus (HPV) infection and subsequent cancer development. Due to the lack of adequate in vitro models for SCJ, however, investigations into its physiological roles and vulnerability to carcinogenesis have been limited. By using Matrigel-based three-dimensional culture techniques, we propagated organoids derived from the normal SCJ region, along with metaplastic squamous cells in the TZ. Consisting predominantly of squamous cells, organoids basically exhibited a dense structure. However, at least in some organoids, a small but discrete population of mucin-producing endocervix cells co-existed adjacent to the squamous cell population, virtually recapitulating the configuration of SCJ in a TZ background. In addition, transcriptome analysis confirmed a higher expression level of many SCJ marker genes in organoids, compared to that in the immortalized cervical cell lines of non-SCJ origin. Thus, the obtained organoids appear to mimic cervical SCJ cells and, in particular, metaplastic squamous cells from the TZ, likely providing a novel platform in which HPV-driven cervical cancer development could be investigated.

Cancers arising from the biliary tract are refractory to conventional therapies, requiring the development of novel therapeutics. However, only a limited number of genetically engineered mouse models have been created, partly due to time-consuming work required. Besides, liver-specific gene manipulation mostly resulted in concurrent development of hepatocellular carcinoma, another type of liver cancer, and gall bladder-restricted gene targeting is still not feasible. Consequently, establishment of cancer type-specific disease modeling remains a technical challenge. To address this issue, we took an alternative cell-based approach to quickly induce tumorigenesis ex vivo. Specifically, murine primary organoids from liver and gall bladder were transduced with lentiviral vectors to reconstitute genetic alterations common in biliary tract cancers, followed by inoculation in immunodeficient mice. Whereas any single genetic alteration did not induce tumors, mutant Kras and repression of major tumor suppressors cooperated for tumor development within two months. Induced lesions varied among normal, dysplastic and papillary lesions to adenocarcinoma, recapitulating multi-step tumorigenesis even in a heterotopic situation. We further demonstrated that two putative oncogenes in intrahepatic cholangiocellular carcinoma, mutant Pik3ca and FGFR2-AHCYL1 fusion, were rather modest drivers for liver-derived organoids, probably requiring additional mutations or hepatic niche to robustly induce full-blown tumors. Thus, we showed that cancer cells could be readily generated from primary cells in the biliary tract, at least in cases where genetic factors play dominant roles. Collectively, the present study will likely contribute to gaining mechanistic insights into biliary carcinogenesis and providing valuable resources for drug discovery.

Lung cancer is the most common cause of cancer mortality, however, efficient methods to culture, expand and transform lung epithelial (LE) cells have not been established. In the present study, an efficient ex vivo method was applied to recapitulate lung carcinogenesis using mouse LE cells. A Matrigel-assisted three-dimensional culture was used to isolate and selectively expand LE cells from mouse lungs. Purified LE cells were passaged and expanded for at least 2 to 3 months while maintaining epidermal growth factor-dependence. LE cells were also easily transformed by genetic manipulations using retroviral vectors. A SV40 large-T antigen, suppressing p53 and pRB, plus an activated oncogene, such as KrasG12V or EGFRex19del, were required to transform LE cells. Transformed cells formed tumors resembling non-small cell lung cancer (NSCLC) in allograft models and exhibited strong oncogene addiction. This experimental system provided a unique model system to study lung tumorigenesis and develop novel therapeutics against NSCLC.

Dysplasia represents a preneoplastic status in multistep colon carcinogenesis. Whereas laborious preparation of thin sections is required for its diagnosis, we here show that newly defined aberrant crypt foci (ACF) simply mark the majority of the dysplasia on the whole colon. Specifically, decoloring of the azoxymethane-treated rat colon after scoring classical ACF (cACF) resulted in visualization of a subset of aberrant crypts that remained densely stained. They were morphologically classified into three subtypes, of which two with compressed luminal openings proved highly correlated with dysplasia. Accordingly, we designated those foci harboring either of the two crypt subtypes as dysplasia-associated ACF (dACF). By serially applying different detection methods for known preneoplastic lesions to the same colon, we showed that most dACF had already been identified as cACF, and a few newly identified dACF contained an entire population of more advanced lesions, such as flat ACF and mucin-depleted foci. Consequently, integrative scoring of cACF and dACF enabled capture of all early lesions of the colon. Furthermore, 94% of the dACF showed dysplasia and 90% of the dysplastic lesions proved to be dACF. Thus, dACF is a promising marker for dysplasia, likely facilitating precise identification of the early stages of colon carcinogenesis.

Leptin, secreted by the adipose tissue and known to be related to obesity, is considered to be involved in the onset and progression of colorectal cancer. However, the exact role of leptin in colorectal carcinogenesis is still unclear, as several controversial reports have been published on the various systemic effects of leptin. The aim of this study was to clarify the local and precise roles of leptin receptor (LEPR)-mediated signaling in colonic carcinogenesis using intestinal epithelium-specific LEPRb conditional knockout (cKO) mice. We produced and used colonic epithelium-specific LEPRb cKO mice to investigate the carcinogen-induced formation of aberrant crypt foci (ACF) and tumors in the colon, using their littermates as control. There were no differences in the body weight or systemic condition between the control and cKO mice. The tumor sizes and number of large-sized tumors were significantly lower in the cKO mice as compared with those in the control mice. On the other hand, there was no significant difference in the proliferative activity of the normal colonic epithelial cells or ACF formation between the control and cKO mice. In the control mice, marked increase of the LEPRb expression level was observed in the colonic tumors as compared with that in the normal epithelium; furthermore, signal transducer and activator of transcription (STAT3) was activated in the tumor cells. These findings suggest that STAT3 is one of the important molecules downstream of LEPRb, and LEPRb/STAT3 signaling controls tumor cell proliferation. We demonstrated the importance of local/regional LEPR-mediated signaling in colorectal carcinogenesis.

Obesity is highly associated with colon cancer development. Whereas it is generally attributed to pro-tumorigenic effects of high fat diet (HFD), we here show that a common genetic basis for predisposition to obesity and colon cancer might also underlie the close association. Comparison across multiple rat strains revealed that strains prone to colon tumorigenesis initiated by a dietary carcinogen amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) tended to develop obesity. Through transcriptome and extensive immunoblotting analyses, we identified the basal level of activated AKT in colonic crypts as a biomarker for the common predisposition. Notably, PhIP induced activation of AKT, which could persist for several weeks under a low fat diet (LFD), but not under HFD. On the other hand, PhIP and HFD independently induced Wnt pathway activation and inhibited apoptosis, through distinct mechanisms involving GSK-3β, caspase 3 and poly-ADP ribose polymerase (PARP). Taken together, these observations provide mechanistic insights into how PhIP-induced activation of AKT might cooperate with HFD at multiple levels toward development of colon cancer.

Animal models for human colorectal cancer recapitulate multistep carcinogenesis that is typically initiated by activation of the Wnt pathway. Although potential roles of both genetic and environmental modifiers have been extensively investigated in vivo, it remains elusive whether epithelial cells definitely require interaction with stromal cells or microflora for tumor development. Here we show that tumor development could be simply induced independently of intestinal microenvironment, even with WT murine primary intestinal cells alone. We developed an efficient method for lentiviral transduction of intestinal organoids in 3D culture. Despite seemingly antiproliferative effects by knockdown of adenomatous polyposis coli ( APC ), we managed to reproducibly induce APC -inactivated intestinal organoids. As predicted, these organoids were constitutively active in the Wnt signaling pathway and proved tumorigenic when injected into nude mice, yielding highly proliferative tubular epithelial glands accompanied by prominent stromal tissue. Consistent with cellular transformation, tumor-derived epithelial cells acquired sphere formation potential, gave rise to secondary tumors on retransplantation, and highly expressed cancer stem cell markers. Inactivation of p53 or phosphatase and tensin homolog deleted from chromosome 10, or activation of Kras, promoted tumor development only in the context of APC suppression, consistent with earlier genetic studies. These findings clearly indicated that genetic cooperation for intestinal tumorigenesis could be essentially recapitulated in intestinal organoids without generating gene-modified mice. Taken together, this in vitro model for colon cancer described herein could potentially provide unique opportunities for carcinogenesis studies by serving as a substitute or complement to the currently standard approaches.

We previously reported the anti-inflammatory effects of cilostazol, a selective inhibitor of phosphodiesterase 3, and two antioxidants, enzymatically modified isoquercitrin and α-lipoic acid in a dextran sodium sulphate-induced colitis mouse model. We further examined the chemopreventive effects of these substances in a murine azoxymethane/dextran sodium sulphate -induced colorectal carcinoma model and compared the effects with those of the well-known anticancer natural plant pigment, anthocyanin. In addition, the effects on cell proliferation activity were evaluated in colon cancer cell lines and mucosal epithelial cells in a model of acute dextran sodium sulphate-induced colitis. Cilostazol and enzymatically modified isoquercitrin improved the outcome of azoxymethane/dextran sodium sulphate-induced colorectal cancer along with anthocyanin though inhibiting inflammation and cell proliferation, but the effect of α-lipoic acid was minimal. Inhibition of cell proliferation by cilostazol was confirmed in vitro. In the acute dextran sodium sulphate-induced colitis model, cilostazol and enzymatically modified isoquercitrin prevented the decrease in epithelial proliferative cells. These results indicate that cilostazol and enzymatically modified isoquercitrin first exhibited an anti-dextran sodium sulphate effect at the initial stage of colitis and then showed antitumour effects throughout subsequent inflammation-related cancer developmental stages.

Lentivirus-based gene delivery works efficiently for the majority of mammalian cells cultured under standard two-dimensional conditions. By contrast, intestinal epithelial organoids embedded into three-dimensional extracellular matrix appear to be resistant to lentiviral transduction. We observed that Matrigel, a matrix that reconstitutes a basement membrane and is indispensable for cell survival and proliferation, prevents lentiviruses from binding to intestinal cells. In this chapter, we describe a simple method of a highly efficient gene transduction into intestinal organoids. This method involves organoid dispersion into single intestinal epithelial cells, mixing these individual cells with lentiviral particles, plating on Matrigel, and subsequent re-embedding into Matrigel. Under these conditions, the majority of the cells are exposed to the virus in the absence of the matrix barrier while remaining attached to the matrix. Using a GFP-labeled lentivirus, we demonstrate that this method allows for highly efficient infection of intestinal organoids after overnight incubation of Matrigel-attached cells with lentiviral particles.

Lentivirus-based gene delivery works efficiently for the majority of mammalian cells cultured under standard two-dimensional conditions. By contrast, intestinal epithelial organoids embedded into three-dimensional extracellular matrix appear to be resistant to lentiviral transduction. We observed that Matrigel, a matrix that reconstitutes a basement membrane and is indispensable for cell survival and proliferation, prevents lentiviruses from binding to intestinal cells. In this chapter, we describe a simple method of a highly efficient gene transduction into intestinal organoids. This method involves organoid dispersion into single intestinal epithelial cells, mixing these individual cells with lentiviral particles, plating on Matrigel, and subsequent re-embedding into Matrigel. Under these conditions, the majority of the cells are exposed to the virus in the absence of the matrix barrier while remaining attached to the matrix. Using a GFP-labeled lentivirus, we demonstrate that this method allows for highly efficient infection of intestinal organoids after overnight incubation of Matrigel-attached cells with lentiviral particles.

Aim: Endoscopic screening and removal of colorectal adenomas can reduce the incidence of colorectal cancer. However, given the possibility of adenoma recurrence, surveillance colonoscopy is currently recommended after the initial screening and removal of colorectal adenomas. Aberrant crypt foci (ACF) have been shown to serve as a reliable surrogate marker of colorectal carcinogenesis. In this study, the relationship between the number of ACF at the initial endoscopic polypectomy and the likelihood of colorectal adenoma recurrence after polypectomy were investigated. Methods: High-magnification chromoscopic colonoscopy was performed in 82 subjects who underwent endoscopic polypectomy to identify ACF in the lower rectum. Surveillance colonoscopy was then performed 3 years after the baseline polypectomy at Yokohama City University Hospital. Results: The number of ACF was greater in patients who showed adenoma recurrence (7.88 ± 6.35) than in those who did not (2.19 ± 2.95) (P

SummaryThe energetically demanding process of translation is linked to multiple signaling events through mTOR-mediated regulation of eukaryotic initiation factor (eIF)4F complex assembly. Disrupting mTOR constraints on eIF4F activity can be oncogenic and alter chemotherapy response, making eIF4F an attractive antineoplastic target. Here, we combine a newly developed inducible RNAi platform and pharmacological targeting of eIF4F activity to define a critical role for endogenous eIF4F in Myc-dependent tumor initiation. We find elevated Myc levels are associated with deregulated eIF4F activity in the prelymphomatous stage of the Eμ-Myc lymphoma model. Inhibition of eIF4F is synthetic lethal with elevated Myc in premalignant pre-B/B cells resulting in reduced numbers of cycling pre-B/B cells and delayed tumor onset. At the organismal level, eIF4F suppression affected a subset of normal regenerating cells, but this was well tolerated and rapidly and completely reversible. Therefore, eIF4F is a key Myc client that represents a tumor-specific vulnerability.

The splicing factor SF2/ASF is an oncoprotein that is up-regulated in many cancers and can transform immortal rodent fibroblasts when slightly overexpressed. The mTOR signaling pathway is activated in many cancers, and pharmacological blockers of this pathway are in clinical trials as anticancer drugs. We examined the activity of the mTOR pathway in cells transformed by SF2/ASF and found that this splicing factor activates the mTORC1 branch of the pathway, as measured by S6K and eIF4EBP1 phosphorylation. This activation is specific to mTORC1 because no activation of Akt, an mTORC2 substrate, was detected. mTORC1 activation by SF2/ASF bypasses upstream PI3K/Akt signaling and is essential for SF2/ASF-mediated transformation, as inhibition of mTOR by rapamycin blocked transformation by SF2/ASF in vitro and in vivo . Moreover, shRNA-mediated knockdown of mTOR, or of the specific mTORC1 and mTORC2 components Raptor and Rictor, abolished the tumorigenic potential of cells overexpressing SF2/ASF. These results suggest that clinical tumors with SF2/ASF up-regulation could be especially sensitive to mTOR inhibitors.

Purpose: Hepatocellular carcinoma is the most common primary malignancy of the liver and accounts for as many as one million deaths annually worldwide. The present study was done to identify new transmembrane molecules for antibody therapy in hepatocellular carcinoma. Experimental Design: Gene expression profiles of pooled total RNA from three tissues each of moderately differentiated and poorly differentiated hepatocellular carcinoma were compared with those of normal liver, noncancerous liver tissue in hepatocellular carcinoma patients, 30 normal tissue samples, and five fetal tissue samples. Target genes up-regulated specifically in hepatocellular carcinoma were validated by immunohistochemical analysis and complement-dependent cytotoxicity assay using monoclonal antibodies generated against target molecules. Results: The human homologue of the Drosophila Roundabout gene, axon guidance receptor homologue 1, ROBO1/DUTT1, a member of the immunoglobulin superfamily, was highly expressed in hepatocellular carcinoma, whereas it showed only a limited distribution in normal tissues. On immunohistochemical analysis using a newly generated anti-ROBO1 monoclonal antibody, positive signals were observed in 83 of 98 cases of hepatocellular carcinoma (84.7%). The mAb B2318C induced complement-dependent cytotoxicity in ROBO1-expressing cell lines and in the liver cancer cell line PLC/PRF/5. Strikingly, the ectodomain of ROBO1 was detected not only in the culture medium of liver cancer cell lines (PLC/PRF/5, HepG2, etc.) but also in sera from hepatocellular carcinoma patients (6 of 11). Conclusions: This is the first report that ROBO1 is overexpressed in hepatocellular carcinoma and shed into serum in humans. These observations suggest that ROBO1 is a potential new serologic marker for hepatocellular carcinoma and may represent a new therapeutic target.

Hepatocyte nuclear factor-4alpha (HNF4alpha) exists in multiple isoforms that are generated by alternative promoter (P1 and P2) usage and splicing. Here we establish monoclonal antibodies (mAbs) for detecting P1 and P2 promoter-driven HNF4alpha, and evaluate their expression in normal adult human tissues and surgically resected carcinomas of different origins. Using immunohistochemical analysis, we demonstrate that, while P1 promoter-driven HNF4alpha is expressed in hepatocytes, small intestine, colon, kidney and epididymis, P2 promoter-driven HNF4alpha is expressed in bile duct, pancreas, stomach, small intestine, colon and epididymis. Altered expression patterns of P1 and P2 promoter-driven HNF4alpha were observed in gastric, hepatocellular and colorectal carcinomas. HNF4alpha was expressed in lung metastases from renal cell, hepatocellular and colorectal carcinoma but was not observed in lung tumours. The P1 and P2 promoter-driven HNF4alpha expression pattern of tumour metastases correlated with the primary site of origin. P1 promoter-driven HNF4alpha was also found in intestinal metaplasia of the stomach. These data provide evidence for the tissue distribution of P1 and P2 promoter-driven HNF4alpha at the protein level and suggest that HNF4alpha may be a novel diagnostic marker for metastases of unknown primary. We propose that the dysregulation of alternative promoter usage of HNF4alpha is associated with the pathogenesis of certain cancers.

Expression profiling of hepatocellular carcinoma has demonstrated that glypican 3 (GPC3), a heparan sulfate proteoglycan anchored to the membrane, is expressed at a markedly elevated level in hepatocellular carcinoma. In this paper, two monoclonal antibodies against GPC3, GPC3-C02 and A1836A, were confirmed to specifically recognize GPC3 molecule in cells from hepatocellular carcinoma and hepatoblastoma cell lines by immunoblotting, and both were confirmed to recognize different epitopes of the GPC3 molecule by epitope mapping. Then, we evaluated the feasibility of GPC3-immunohistochemistry in the pathological diagnosis of benign and malignant hepatocellular lesions by applying these monoclonal antibodies to formalin-fixed and paraffin-embedded specimens. The immunoreactivity turned out to be identical in the two monoclonal antibodies and was thus confirmed to represent the actual expression of the GPC3 molecule. The expression was observed in the fetal liver, but not in normal adult liver, liver cirrhosis or hepatitis except for a tiny focus of a regenerative nodule of fulminant hepatitis. Diffusely positive staining of GPC3 was observed in malignant hepatocytes in hepatoblastomas and in hepatocellular carcinomas (47/56, 84%). GPC3 expression was independent of the differentiation and size of the hepatocellular carcinoma. On the other hand, there was only weak and focal staining in low-grade (2/8) and high-grade dysplastic nodules (6/8). GPC3 immunoreactivity was detected in only one of 23 metastatic lesions of colorectal carcinoma, and its expression was entirely absent in the liver cell adenoma (0/7), carcinoid tumor (0/1), and cholangiocellular carcinoma (0/16). When compared with immunohistochemistry of hepatocyte antigen and alpha-fetoprotein, GPC3-immunohistochemistry was significantly much more specific and sensitive for hepatocellular carcinomas. Thus, GPC3 was confirmed to be one of the oncofetal proteins now attracting attention for their promise both as markers of hepatocellular carcinoma in routine histological examination and as targets in monoclonal antibody-based hepatocellular carcinoma therapy.

Mucins are secreted or transmembrane glycoproteins that are expressed mainly in the digestive tract. This family of proteins has been the focus of much gastric cancer research as some transmembrane mucins are implicated in tumorigenesis and make attractive targets for cancer diagnosis and therapeutics. Mucins have also been utilized to classify gastric cancer by differentiating between gastric and intestinal phenotypes. Here we show that transmembrane mucin MUC13 is upregulated in gastric cancer. By quantitative real-time reverse transcription-polymerase chain reaction and immunoblot analysis, overexpression of MUC13 was verified in more than half of the samples examined. In immunohistochemical analysis, MUC13 staining was observed in 74 of 114 cases of gastric cancer (64.9%), predominantly in intestinal type (P < 0.001), and in 9 of 10 cases of intestinal metaplasia, precancerous lesions of intestinal-type gastric cancer, but not observed in normal gastric mucosa. Moreover, MUC13 staining patterns characteristic of histological type were identified: staining was on the apical side of tubular glands in intestinal type and on the cytoplasm in diffuse type. These results suggest that MUC13 is a good differentiation marker for gastrointestinal mucosa and that it may have a causal role that correlates with two distinct gastric tumorigenesis pathways.