bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A19: Phosphorylation results in nuclear translocation of Dicer protein that increases metabolism, accelerates aging, and alters tumorigenesis
Authors: Aryal Neeraj K. , Arur Swathi , Lozano Guillermina
Published: May 2018

Dicer is a well-conserved and essential gene that is required for the production of micro RNAs that play key roles during development and cancer. Several studies have associated aberrant Dicer expression in humans with developmental defects (Dicer1 syndrome) and poor prognosis in various cancers. One important mechanism of controlling protein stability and function is through post-translational modification. Recently, Extracellular signal-Regulated Kinase (ERK) dependent phosphorylation of Dicer during oogenesis has been shown to be essential in C. elegans. The phosphorylation sites in Dicer (Ser1718 and Ser1842 in mice) are well conserved and the phosphorylation is necessary and sufficient for Dicer's translocalization from cytoplasm to nucleus. We are interested in understanding the phosphorylation-mediated control of Dicer function during development and cancer. To understand the role of phospho-Dicer in mammals, we have generated five new Dicer1 alleles including phospho-mimetic mouse models with both serines replaced with aspartic acids (DicerS2D), only Ser1842 replaced with aspartic acid (DicerS1842D), and only Ser1718 replaced with aspartic acid (DicerS1718D).

Phenotypic study shows that >75% of DicerS2D/S2D mutants and >60% of DicerS1842D/S1842D mutants die within five days after birth, while all heterozygous mutants and DicerS1718D/S1718D mice are phenotypically normal. The DicerS2D/S2D and DicerS1842D/S1842D survivors show signs of accelerated aging including smaller size, hunching of backbone, compromised weight gain, infertility, systemic tissue atrophy, and early lethality. We have also observed that DicerS2D/S2D animals and MEFs have increased metabolism as compared with wild type. Since aging and cancer are closely linked and altered metabolism is a hallmark of cancer, we hypothesize that phosphorylated Dicer produces an altered miRNA profile that affects metabolism, leading to developmental defects and tumorigenesis. Transcriptional profiling of MEFs and testes have shown that miRNA profiles are very different in mutants than in wild type, and the most affected pathways are metabolism and cancer. To test the role of phospho-Dicer in tumorigenesis, we crossed the DicerS2D allele into KRasLA1/+ driven nonmetastatic tumor model. The results show that phospho-Dicer reduces tumor-free survival, changes tumor spectrum, and drives metastasis in this tumor model.

Citation Format: Neeraj K. Aryal, Swathi Arur, Guillermina Lozano. Phosphorylation results in nuclear translocation of Dicer protein that increases metabolism, accelerates aging, and alters tumorigenesis [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A19.
Abstract A28: Understanding the role of the tumor suppressor p53 in pancreatic cancer development
Authors: Flowers Brittany M. , Garcia Patty B. , Grüner Barbara M. , Winslow Monte M. , Attardi Laura D.
Published: May 2018

In the next decade, pancreatic ductal adenocarcinoma (PDAC) is projected to be the second leading cause of cancer-related death. This high rate of mortality is attributed to late-stage diagnosis and lack of effective therapeutic strategies. The tumor-suppressor gene TP53 is mutated in ~75% of PDAC patients. The most frequently observed TP53 mutations in PDAC occur within the DNA binding domain at codons 175 and 273. TP53 mutations may induce loss of wild-type p53 function and gain of novel, oncogenic functions. We aim to use different mouse models of PDAC to identify the molecular pathways deregulated when wild-type p53 is lost and mutant p53 is expressed, to elucidate the molecular mechanisms driving PDAC development. While previous studies have suggested that point mutant p53 drives gain-of-function phenotypes, our studies of aging Pdx1-Cre;KrasLSL-G12D/+;Rosa26LSL-tdTomato/LSL-tdTomato mice with conditional p53 knockout (p53Flox/Flox or p53Flox/Null) or p53 mutation (p53LSL-R172H/Flox or p53LSL-R172H/Null) did not demonstrate a clear mutant p53 gain-of-function phenotype in tumor latency. We hypothesize that tumor latency is too rapid in these models to manifest a clear gain-of-function phenotype, requiring the establishment of different model systems. Indeed, our preliminary studies using tumor-derived p53R172H cell lines and isogenic p53 null cell lines suggest a role for mutant p53 gain of function in later-stage tumorigenesis, specifically in metastatic seeding. Furthermore, we are evaluating the role of the putative PDAC cells of origin, pancreatic acinar and ductal cells, in PDAC development. Using both tumor-derived mouse cell lines and pancreatic lineage-specific genetically engineered mouse models of PDAC, we can evaluate the consequences of loss of wild-type p53 expression and gain of mutant p53 expression in different pancreatic compartments. Ultimately, using these systems we aim to elucidate the target genes and molecular pathways controlled by wild-type p53 or by mutant p53 to regulate PDAC initiation. Understanding the molecular mechanisms driving PDAC initiation is critical for the development of new therapeutic strategies for early detection and effective intervention in PDAC patients.

Citation Format: Brittany M. Flowers, Patty B. Garcia, Barbara M. Grüner, Monte M. Winslow, Laura D. Attardi. Understanding the role of the tumor suppressor p53 in pancreatic cancer development [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A28.
Abstract A31: Biallelic Dicer1 loss in endothelial cells drives angiosarcoma development
Authors: Hanna Jason A. , Drummond Catherine J. , Garcia Matthew R. , Go Jonathan C. , Finkelstein David , Rehg Jerold E. , Hatley Mark E.
Published: May 2018

Angiosarcoma is an aggressive and highly metastatic vascular sarcoma with an extremely poor prognosis. Because of the rarity of the disease, the molecular drivers and optimal treatment strategies for patients remain unclear, highlighting the need for novel genetic and in vivo animal models. MicroRNAs are small RNAs that regulate gene expression and DICER1 is the RNase III endoribonuclease that processes pre-microRNAs into mature microRNAs. DICER1 and microRNAs are central to numerous cellular processes and are often dysregulated in many cancers, including sarcomas. Here we show that biallelic Dicer1 deletion with endothelial expression of aP2-Cre drives aggressive and metastatic angiosarcoma independent of other genetically engineered oncogenes or tumor suppressor loss. Angiosarcomas in aP2-Cre;Dicer1Flox/- mice histologically and genetically resemble human angiosarcoma, and we found microRNA-23 target genes enriched in mouse and human angiosarcoma. Because Ras mutations and Cdkn2a loss are common in angiosarcoma, we interrogated them as angiosarcoma modifiers. Interestingly, we found that both oncogenic LSL-KrasG12D and loss of conditional Cdkn2aFlox decreased tumor latency. In addition, aP2-Cre;LSL-KrasG12D;Cdkn2aFlox/Flox mice developed angiosarcomas, providing a model with Dicer1 expression intact to further study the function of microRNAs in angiosarcoma. Thus, these findings illustrate that Dicer1 can function as a traditional loss-of-function tumor-suppressor gene and provide simple and fully penetrant animal models for the study of angiosarcoma development and metastasis.

Citation Format: Jason A. Hanna, Catherine J. Drummond, Matthew R. Garcia, Jonathan C. Go, David Finkelstein, Jerold E. Rehg, Mark E. Hatley. Biallelic Dicer1 loss in endothelial cells drives angiosarcoma development [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A31.
Abstract A43: Loss of Keap1 promotes KRAS-driven lung cancer and results in genotype-specific vulnerabilities
Authors: Romero Rodrigo , Sayin Volkan I. , Shawn Davidson M. , Bauer Matthew , Singh Simranjit X. , LeBoeuf Sarah , Karakousi Triantafyllia R. , Ellis Donald C. , Bhutkar Arjun , Sanchez-Rivera Francisco , Subbaraj Lakshmipriya , Martinez Britney , Bronson Roderick T. , Prigge Justin R. , Schmidt Edward E. , Thomas Craig J. , Davies Angela , Dolgalev Igor , Heguy Adriana , Allaj Viola , Piorier John T. , Moreira Andre L. , Rudin Charles M. , Pass Harvey I. , Heiden Matthew G. Vander , Jacks Tyler , Papagiannakopoulos Thales
Published: May 2018

Treating KRAS mutant lung adenocarcinoma (LUAD) remains a major challenge in cancer treatment given the difficulties associated with directly inhibiting the KRAS oncoprotein1. One approach to addressing this challenge is to define frequently co-occurring mutations with KRAS, which themselves may lead to therapeutic vulnerabilities in tumors. Approximately 20% of KRAS mutant LUAD tumors carry loss-of-function (LOF) mutations in Kelch-like ECH-associated protein 1 (KEAP1)2-4, a negative regulator of nuclear factor erythroid 2-like 2 (NFE2L2; hereafter NRF2), which is the master transcriptional regulator of the endogenous antioxidant response5-10. The high frequency of mutations in KEAP1, which would be predicted to result in activation of the NRF2 pathway, suggests an important role for the oxidative stress response in lung tumorigenesis. To test this directly, we used a CRISPR/Cas9-based approach in a mouse model of Kras-driven LUAD to examine the effects of loss of KEAP1 function in lung cancer progression. We show that loss of KEAP1 hyper-activates Nrf2 and promotes Kras-driven LUAD. Combining CRISPR/Cas9-based genetic screening and metabolomic analyses, we also show that KEAP1/NRF2 mutant cancers are dependent on increased glutaminolysis, and this property can be therapeutically exploited through the pharmacologic inhibition of glutaminase. Finally, we provide a rationale for sub-stratification of human lung cancer patients with KRAS-KEAP1 or -NRF2 mutant tumors as likely to respond to glutaminase inhibition.

Citation Format: Rodrigo Romero, Volkan I. Sayin, Davidson M. Shawn, Matthew Bauer, Simranjit X. Singh, Sarah LeBoeuf, Triantafyllia R. Karakousi, Donald C. Ellis, Arjun Bhutkar, Francisco Sanchez-Rivera, Lakshmipriya Subbaraj, Britney Martinez, Roderick T. Bronson, Justin R. Prigge, Edward E. Schmidt, Craig J. Thomas, Angela Davies, Igor Dolgalev, Adriana Heguy, Viola Allaj, John T. Piorier, Andre L. Moreira, Charles M. Rudin, Harvey I. Pass, Matthew G. Vander Heiden, Tyler Jacks, Thales Papagiannakopoulos. Loss of Keap1 promotes KRAS-driven lung cancer and results in genotype-specific vulnerabilities [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A43.
Abstract A49: Using IL10-/- mouse model to assess heavy-ion radiation exposure-associated colitis and colorectal cancer incidence
Authors: Suman Shubhankar , Moon Bo-Hyun , Fornace Albert J. , Datta Kamal
Published: May 2018

Underlying risk of γ-ray-induced colitis and colorectal cancer incidence is emphasized by the studies on atom bomb survivors and also in patients undergoing radiotherapy. However, uncertainties in colitis and CRC risk prediction after exposure to high-LET space (particle) radiation exposure has not been realized due to lack of reliable in vivo data. Here we report IL10-/- mice as a suitable mouse model for assessment of colitis and CRC risk after exposure to space radiation.

Male mice (n=12 mice/group) were whole-body exposed to sham-radiation, γ-rays (137Cs-source, 2.0 Gy), and 28Si-ion (300 MeV/n; 70 keV/μm; 1.4 Gy). We used γ-ray equitoxic doses using relative biologic effectiveness (RBE) values determined earlier. Mice were sacrificed 90 days after irradiation, and colon swiss rolls were prepared and histopathologic assessment of colitis score and CRC grade was noted. Further, inflammation-associated gene-expression analysis was conducted in both radiation-induced tumor and adjoining normal tissue area. Immunohistochemistry (β-catenin, Cyclin-D1, and phospho-histone H3) was also performed to assess HZE-induced proliferative signaling.

Relative to controls and γ-ray, colitis score, colon tumor incidence, size, and grade were significantly higher after space (28Si-ion) radiation exposure. Additionally, tumor incidence per unit of radiation (per cGy) was also higher after 28Si-ion radiation relative to γ radiation. Higher number of phospho-histone H3-positive cells in 28Si-ion exposed mouse colon demonstrated increased proliferative index resulting in increased intestinal tumors of larger size and grade was due to greater activation of β-catenin and its downstream effector cyclin D1. Inflammatory gene signature was more pronounced after 28Si-ion exposure. Significant upregulation of GATA4, ICAM1, ITGA2, and EGFR was exclusive to 28Si-ion exposed mouse colon; however, PTGES and TGFβ1 were upregulated in both γ and 28Si-ion exposed mice.

Overall, our findings suggest that IL10-/- mice are a suitable model to assess IR-induced colitis and CRC risk and space radiation carries higher risk of colitis and CRC incidence, relative to γ-rays at comparable doses. This study has implications for risk prediction in astronauts planning for deep-space missions and also for cancer patients planning to undergo particle radiotherapy.

Citation Format: Shubhankar Suman, Bo-Hyun Moon, Albert J. Fornace, Jr., Kamal Datta. Using IL10-/- mouse model to assess heavy-ion radiation exposure-associated colitis and colorectal cancer incidence [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A49.
Abstract A52: Arid1a exerts context-dependent oncogenic and tumor suppressor functions in liver cancer
Authors: Sun Xuxu , Wang Sam , Zhang Shuyuan , Zhu Hao
Published: May 2018

ARID1A, an ATP-dependent SWI/SNF chromatin remodeling complex component, is hypothesized to be one of the most commonly mutated tumor suppressors in human cancer. Using mouse liver cancer models, we sought to elucidate the functional consequences of ARID1A gain and loss. Surprisingly, mice with liver-specific Arid1a deficiency were resistant to chemical- and MYC-induced liver carcinogenesis, while ARID1A overexpression accelerated tumorigenesis when combined with a variety of oncogenes, indicating an important role during tumor initiation. Mechanistically, Arid1a promoted tumor initiation by increasing cytochrome P450-mediated oxidative stress. In human HCCs, late ARID1A loss has been observed upon metastatic spread, suggesting that deleterious mutations do occur after tumor initiation. Indeed, both homozygous and heterozygous loss after liver tumor formation in mice were sufficient to drive progression and metastasis. Intriguingly, the Arid1a haploinsufficient state was sufficient to globally increase chromatin occupancy and downregulate metastasis suppressor genes within tumors. In summary, ARID1A can play both tumor-suppressive and oncogenic roles in liver cancer in a temporally dependent manner, explaining the expression and mutation patterns seen in human HCC.

Citation Format: Xuxu Sun, Sam Wang, Shuyuan Zhang, Hao Zhu. Arid1a exerts context-dependent oncogenic and tumor suppressor functions in liver cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A52.
Abstract B07: Role of lysyl hydroxylases in metastatic lung cancer
Authors: Liu Wei , Zhang Ting , Guo Lixia , Wang Yuanyuan , Yang Yanan
Published: May 2018

Lung cancer remains the leading cause of cancer-related death, partly due to the fact that most patients are diagnosed with metastatic disease, which is the main cause of death, yet effective therapeutics are lacking. Utilizing mouse models of metastatic lung adenocarcinomas, we report that the transcription factor GATA3 and its cofactor FOG2 play critical roles in lung adenocarcinoma metastasis by promoting the expression of the lysyl hydroxylase (LH) family members, which in turn regulate the tumorigenicity and motility of lung tumor cells through both EMT and EMT-independent mechanisms. In vivo, LHs are elevated in human lung adenocarcinomas and are associated with worse patient survival. Collectively, our data suggest that targeting LHs may be useful for treating metastatic lung cancer.

Citation Format: Wei Liu, Ting Zhang, Lixia Guo, Yuanyuan Wang, Yanan Yang. Role of lysyl hydroxylases in metastatic lung cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B07.
Abstract B13: The prevention of lymphoproliferative lesions arising in patient-derived cancer xenografts by anti-graft-versus-host-disease agents
Authors: Chijiwa Tsuyoshi , Noguchi Akira , Komura Daisuke , Katayama Makoto , Haraguchi Mizuha , Hashimoto Haruo , Suemizu Hiroshi , Nakamura Yoshiyasu , Furukawa Daisuke , Isagawa Takayuki , Katoh Hiroto , Moriya Takashi , Ishikawa Shumpei , Nakamura Masato , Miyagi Yohei
Published: May 2018

Xenografts derived from engrafting fresh surgical specimens directly onto immunodeficient mice have enabled the development of more relevant in vivo models for human cancers. Such patient-derived xenograft (PDX) models retain similar morphology, heterogeneities, and molecular signatures with the original cancers. We reported the rapid and efficient establishment of PDXs using super-immunodeficient NOG mice (PDX/NOG models). During the establishment process, a transplantable lymphoproliferative lesion (LPL) that replaces the original tumor cells sometimes occurs. The occurrence of LPL is the most problematic aspect of the establishment of PDX. This phenomenon may arise because of the Epstein-Barr virus due to the severely immunodeficient nature of the animal model; however, the mechanisms underlying LPL have not yet been elucidated in detail. In the present study, we histologically analyzed and tried to prevent the occurrence of LPL in PDX/NOG.

Over 100 lines of cancer xenografts were established in our previous studies. Throughout these processes, we also established 10 LPL-PDX lines. Some LPL-PDX lines consist of B cells, T cells, and differentiated plasma cells. These LPL lymphocytes exhibited negligible proliferative potency in vitro. The invasions of LPL in the liver, lung, and pancreas were observed immunohistochemically.

NOG mice bearing LPL-PDX (LPL-PDX/NOG) were treated with the anti-graft-versus-host-disease (anti-GVHD) drugs FK506 (1.0 mg/kg/day) and mycophenolate mofetil (MMF, 120 mg/kg/day) for 4 weeks using intraperitoneal injections. The LPL proliferations were significantly suppressed with FK506 (p=0.011) and MMF (p=0.014) compared with the control.

The occurrence of LPL during establishment of PDX may be based on the GVHD-like mechanism. This phenomenon can be prevented by using anti-GVHD agents in the severely immunodeficient mice. The LPL-PDX/NOG models are also proposed for the utilization of GVHD mouse models with organic damage, particularly chronic GVHD mouse models.

Citation Format: Tsuyoshi Chijiwa, Akira Noguchi, Daisuke Komura, Makoto Katayama, Mizuha Haraguchi, Haruo Hashimoto, Hiroshi Suemizu, Yoshiyasu Nakamura, Daisuke Furukawa, Takayuki Isagawa, Hiroto Katoh, Takashi Moriya, Shumpei Ishikawa, Masato Nakamura, Yohei Miyagi. The prevention of lymphoproliferative lesions arising in patient-derived cancer xenografts by anti-graft-versus-host-disease agents [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B13.
Abstract B24: Stem cell lineage infidelity drives wound repair and cancer
Authors: Ge Yejing , Fuchs Elaine
Published: May 2018

Human adult tissues harbor resident stem cells (SCs) responsible for homeostasis and wound repair. Tumorigenesis arises when normal SCs accumulate mutations that cause them to derail, shifting their homeostatic balance to favor tissue growth at the expense of differentiation. In contrast to wound repair, where the growth:differentiation imbalance is transient, cancers are refractory to tissue restoration cues, seemingly hijacking these normal cellular programs to fuel their molecular thirst for uncontrolled growth.

The notion that a “cancer is a wound that never heals” has origins dating back to Rudolf Virchow in the 1800s. Since then, intimate connections between wounds and tumors have also been drawn at the molecular level. Although intriguing, it remains unclear which of the normal SC remodeling pathways are exploited by tumor SCs and how cancers rewire preinstalled regulatory networks to support malignancy.

Here, we investigate such a phenomenon in the skin, where during homeostasis, stem cells of epidermis and hair follicle fuel their respective tissues. We find that breakdown of stem cell lineage confinement--granting privileges associated with both fates--is not only a hallmark but also functional in cancer development. We show that lineage plasticity is critical in wound repair, where it operates transiently to redirect fates. Probing the mechanism, we discover that irrespective of cellular origin, lineage infidelity occurs in wounding when stress-responsive enhancers become activated and override homeostatic enhancers that govern lineage specificity. In cancer, stress-responsive transcription factor levels rise, causing lineage commanders to reach excess. When lineage and stress factors collaborate, they activate new oncogenic enhancers that distinguish cancers from wounds.

Citation Format: Yejing Ge, Elaine Fuchs. Stem cell lineage infidelity drives wound repair and cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B24.
Abstract B28: Development of estrogen-dependent and estrogen receptor-negative cervical cancer in HPV transgenic mice
Authors: Son Jieun , Chung Sang-Hyuk
Published: May 2018

Estradiol (E2) and human papillomavirus (HPV) cooperate to cause cervical cancer. The role of estrogen receptor α (ERα) in cervical cancer has been underappreciated. Chronic treatment with E2 promotes the development of cervical cancer in K14E7 transgenic mice expressing HPV16 E7 oncoprotein. In the present study, we bred K14E7 to mice with conditional ablation of Esr1 (ERα-coding gene) in the cervical epithelial cells (Wnt7aCre/Esr1f/f; Esr1ed/ed). We found that E2 promoted the development of ERα cervical cancer in K14E7/Esr1ed/ed mice. In addition, proliferation and apoptotic indices of ERα cancer in K14E7/Esr1ed/ed mice were similar to those of ERα+ cancer in K14E7/Esr1f/f mice. We also found that E2 increased the epithelium thickness and epithelial cell proliferation in the cervix of Esr1ed/ed mice. Our published results have demonstrated that deletion of Esr1 in the cervical stroma promotes the regression of cervical precancer lesions in K14E7 mice. In patients, ERα is expressed in the cancer stroma but not cancer epithelial cells. These observations support that stromal ERα, rather than epithelial ERα, mainly mediates oncogenic E2 signaling for cervical cancer. They also suggest that stromal ERα might be an effective therapeutic target for cervical cancer.

Note: This abstract was not presented at the conference.

Citation Format: Jieun Son, Sang-Hyuk Chung. Development of estrogen-dependent and estrogen receptor-negative cervical cancer in HPV transgenic mice [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B28.
Abstract B29: A carcinogen-induced mouse model recapitulates the molecular alterations of human muscle-invasive bladder cancer
Authors: Fantini Damiano , Glaser Alexander P. , Kalen Rimar J. , Yiduo Wang , Yu Yanni , Meeks Joshua J.
Published: May 2018

Bladder cancer is the fourth most common cancer in men and fifth most common malignancy in the United States. Survival of patients with muscle-invasive or metastatic bladder cancer is poor, with only 35% survival at 5 years. Developing innovative anticancer drugs relies on the availability of model systems that closely recapitulate the corresponding human disease at both the histologic and molecular levels. One of the major limitations in the field of bladder cancer research is the limited availability of such models.

The N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) mouse model is an attractive model system of muscle-invasive bladder cancer (MIBC) since it recapitulates the complex histology of human tumors in a background with intact immune system. However, it was unknown whether this carcinogen-induced model also mimicked human MIBC at the molecular and mutational level.

In our study, we analyzed the mutational landscape of the BBN model by whole-exome sequencing followed by a bioinformatic comparison to human MIBC using genomic data from The Cancer Genome Atlas and other repositories. Similar to human MIBC, BBN tumors had a high mutation burden. Next, we extracted mouse-specific mutational signatures that correspond to different genetic instability processes operating in BBN tumors. Interestingly, one of these de novo extracted signatures aligned to a human mutational signature previously associated to DNA-repair deficiencies in human bladder cancers. We further analyzed the most commonly mutated genes and their intratumor mutation frequencies with the aim of identifying potential driver mutations. Our analyses converged on three genes that seem crucial in the process of tumorigenesis in both mouse and human bladder cancers: the tumor suppressor Trp53 as well as the genes Kmt2c and Kmt2d. These encode for methyltransferases involved in the methylation of histone H3K4 and play a key role in the epigenetic regulation of enhancer activity. Also, many of the putative driver mutations found in the BBN genomes corresponded to human cancer hotspot mutations, supporting their role as driver mutations.

Together, our study revealed several similarities between human MIBC and the BBN mouse model. Our results highlighted the contribution of aberrations to chromatin regulators and genetic instability in both human and BBN bladder tumors, thus providing a strong rationale for the use of this mouse model in molecular and drug discovery studies.

Citation Format: Damiano Fantini, Alexander P. Glaser, Rimar J. Kalen, Wang Yiduo, Yanni Yu, Joshua J. Meeks. A carcinogen-induced mouse model recapitulates the molecular alterations of human muscle-invasive bladder cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B29.
Abstract IA03: Cancer modeling in the CRISPR age
Authors: Ventura Andrea
Published: May 2018

The widespread use of high-throughput genomic methods is profoundly changing the way we understand, classify, and treat cancers, and provides unprecedented opportunities to design therapeutic approaches tailored to individual patients. The success of these efforts is contingent on our ability to identify, among the hundreds of different genetic lesions, those that actively drive tumorigenesis.

The recent development of powerful genome editing methods promises to greatly speed up this process and allows us, for the first time, to model a wide range of previously inaccessible cancer-associated mutations.

I will discuss how CRISPR-based gene editing methods are revolutionizing cancer. I will also show how my group is combining computational methods and in vivo somatic genome editing approaches to generate and characterize novel mouse models of human cancers and to explore the noncoding fraction of the cancer genome.

Citation Format: Andrea Ventura. Cancer modeling in the CRISPR age [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr IA03.
Abstract IA08: Somatic p53 mutations drive development of triple-negative breast cancer with evolutionarily distinct metastases
Authors: Zhang Yun , Xiong Shunbin , Lozano Guillermina
Published: May 2018

Breast cancer is a heterogeneous disease generally comprising four molecular subtypes: luminal A, luminal B, HER-2 enriched, and basal-like. Basal-like breast cancers, the majority of which are triple-negative breast cancers (TNBCs), are the most aggressive with the poorest prognosis and no targeted therapies. The majority of these tumors (80-88%) have mutations in the TP53 tumor suppressor, which suggests an important role for TP53 mutations in tumor initiation and progression. We have created two novel conditional mutant p53 alleles in the mouse, p53wm-R172H and p53wm-R245W. These alleles are wild type, but in response to Cre-mediated recombination, they produce p53R172H and p53R245W proteins that correspond to p53R175H and p53R248W hot spot mutants in human TNBCs. In a somatic breast cancer model, p53 mutations in a few mammary epithelial cells were generated using intraductal injection of Ad-Cre. Importantly, the stroma and immune cells retain wild type p53. p53wm-R172H/+ mice rarely developed breast cancer while p53wm-R172H/fl (includes the p53R172H mutation and a p53-null allele) and p53wm-R245W/+ readily developed breast carcinomas, a subset of which are TNBCs that metastasized to the lung and liver, common sites of human breast cancer metastasis. Whole-exome sequencing of p53R245W tumors revealed different evolution patterns for metastases. These models most closely simulate the genesis of TNBCs and will thus be invaluable in testing novel therapeutic combinations.

Citation Format: Yun Zhang, Shunbin Xiong, Guillermina Lozano. Somatic p53 mutations drive development of triple-negative breast cancer with evolutionarily distinct metastases [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr IA08.
Abstract IA12: Intra- and intertumoral heterogeneity and response to therapy in mouse models of SCLC
Authors: Lim Jing Shan , Yang Dian , Shue Yan Ting , Winslow Monte , Sage Julien
Published: May 2018

Small cell lung cancer (SCLC) is a high-grade neuroendocrine carcinoma that accounts for ~15% of all lung cancers and causes over 200,000 deaths worldwide each year. The majority of SCLC patients have metastatic disease at the time of diagnosis; for these patients, the median survival, even with treatment, is 7-12 months, and the 5-year overall survival is <1%. SCLC is managed with first-line chemotherapy–often cisplatin or carboplatin with etoposide. However, the majority of SCLC patients suffer relapse within months of completing initial therapy due to the persistence of a subpopulation of chemotherapy-resistant cells. Treatment options for SCLC have remained virtually unchanged for the past 30 years, and there are no approved targeted therapies in SCLC.

To dissect the molecular changes that regulate SCLC progression, it is critical to analyze purified SCLC cells from tumors at known stages of tumorigenesis. This has not been possible previously using either mouse models or human specimens due to the 1) limited access to lung cancers at defined stages of malignant progression, 2) inability to unambiguously isolate SCLC cells away from stromal cells, and 3) difficulty in performing genome-wide analyses on the few cells that can be isolated from metastases in mouse models or patient biopsies. To overcome these obstacles, we have developed mouse models of SCLC including Cre/lox-mediated deletion of key tumor suppressors (p53, Rb, and the Rb family member p130) as well as activation of fluorescent reporters. This triple-knockout (TKO) model recapitulates the genetics, histology, and metastatic ability of human SCLC.

Using this mouse model, we have recently identified new levels of intratumoral heterogeneity in SCLC tumors, including the presence of tumor-propagating cells (TPCs) as well as Notch-active non-neuroendocrine tumor cell population that promotes the growth of TPCs in a non-cell autonomous but tumor-intrinsic manner. Using TKO mice, we have also uncovered distinct mechanisms of intertumoral heterogeneity during tumor progression; in particular, we have shown that one group of tumors gains metastatic potential by upregulation of the Nfib transcription factor and extensive changes in their chromatin state, while others become metastatic in absence of Nfib-driven chromatin dynamics. These observations will be discussed in the context of how SCLC tumors respond to chemotherapy and candidate targeted therapies.

Citation Format: Jing Shan Lim, Dian Yang, Yan Ting Shue, Monte Winslow, Julien Sage. Intra- and intertumoral heterogeneity and response to therapy in mouse models of SCLC [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr IA12.
Abstract IA13: Imaging stem cell signals in cancer heterogeneity and therapy resistance
Authors: Reya Tannishtha
Published: May 2018

Our research focuses on the signals that control stem cell self-renewal and how these signals are hijacked in cancer. Using a series of genetic models, we have studied how classic developmental signaling pathways such as Wnt, Hedgehog, and Notch play key roles in hematopoietic stem cell growth and regeneration and are dysregulated during leukemia development. In addition, using real-time imaging strategies we have found that hematopoietic stem cells have the capacity to undergo both symmetric and asymmetric division, and that shifts in the balance between these modes of division are subverted by oncogenes. Further, regulators of this process, including the cell fate determinant Musashi, are critical players in driving progression of solid and liquid cancers and could serve as targets for diagnostics and therapy. Ongoing work is focused on understanding the mechanisms that drive therapy resistance after drug delivery, as well as developing high-resolution in vivo imaging approaches to map normal stem cell behavior and interactions within living animals, and to define how these change during cancer formation.

Citation Format: Tannishtha Reya. Imaging stem cell signals in cancer heterogeneity and therapy resistance [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr IA13.
Abstract PR05: Lineage specifiers SOX2 and NKX2-1 inversely regulate lung tumor immune microenvironment
Authors: Mollaoglu Gurkan , Jones Alex , Mukhopadhyay Anandaroop , Gertz Jason , Jones Kevin , Snyder Eric , Oliver Trudy G.
Published: May 2018

The tumor microenvironment is a critical effector of therapeutic response to diverse stimuli including immunotherapies. Lineage-specific drivers of cancer are known to dictate tumor differentiation and response to therapy, but how they influence the tumor immune microenvironment is largely unknown. SOX2 and NKX2-1 are critical regulators of lung development and cancer, with SOX2 amplifications associated with squamous lung cancer and NKX2-1 amplifications associated with lung adenocarcinoma. Here we employ and develop new genetically engineered mouse models (GEMMs) of lung cancer to interrogate the impact of SOX2 and NKX2-1 on innate immune infiltration. Squamous and adenocarcinoma GEMMs accurately recapitulate features of their human counterparts, including an enrichment of tumor-associated neutrophils (TANs) specifically in squamous lung cancer. We show that SOX2 recruits TANs, whereas NKX2-1 suppresses TANs, in the absence of histopathologic changes. SOX2 and NKX2-1 inversely regulate the neutrophil chemoattractant, Cxcl5, which is also upregulated in human squamous lung tumors. Using a novel GEMM of squamous lung cancer with a rapid latency of 3-4 months, preliminary data suggest that neutrophils can regulate adeno- to squamous transdifferentiation in vivo. Together these data reveal how lineage specifiers influence the tumor immune microenvironment, which in turn may regulate cancer cell fate.

This abstract is also being presented as Poster B19.

Citation Format: Gurkan Mollaoglu, Alex Jones, Anandaroop Mukhopadhyay, Jason Gertz, Kevin Jones, Eric Snyder, Trudy G. Oliver. Lineage specifiers SOX2 and NKX2-1 inversely regulate lung tumor immune microenvironment [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr PR05.
Predicting the Presence of Oral Squamous Cell Carcinoma Using Commonly Dysregulated MicroRNA in Oral Swirls
Authors: Yap Tami , Koo Kendrick , Cheng Lesley , Vella Laura J. , Hill Andrew F. , Reynolds Eric , Nastri Alf , Cirillo Nicola , Seers Christine , McCullough Michael
Published: May 2018

Oral swirls are a noninvasive, rapidly collected source of salivary microRNA (miRNA) potentially useful in the early detection of disease states, particularly oral squamous cell carcinoma (OSCC). The aim of this study was to predict the presence of OSCC using a panel of OSCC-related dysregulated miRNA found in oral swirls, identified jointly in data from formalin-fixed paraffin-embedded (FFPE) and fresh-frozen specimens. Next-generation sequencing (NGS) was used to determine miRNA fold changes in FFPE OSCC specimens relative to histologically normal epithelium. These data were placed with NGS of fresh-frozen tissue data of The Cancer Genome Atlas database to select a panel of commonly dysregulated miRNA. This panel was then analyzed by RT-qPCR in RNA extracted from oral swirls collected from 30 patients with OSCC and 30 controls. Upregulation of miR-31 and miR-21 and downregulation of miR-99a, let-7c, miR-125b, and miR-100 were found between OSCC and controls in both FFPE and fresh-frozen samples. These miRNAs were studied in a training set of 15 OSCC versus 15 control oral swirls to develop a dysregulation score [AUC, 0.95; 95% confidence interval (CI), 0.88–1.03] and classification tree. A test cohort of 15 OSCC versus 15 control oral swirls yielded a dysregulation score AUC of 0.86 (95% CI, 0.79–1.00) with the classification tree identifying 100% (15/15) of OSCC and 67% (10/15) of controls. This study debuts the use of OSCC-associated miRNA, commonly dysregulated in both FFPE and frozen specimens, in oral swirls to indicate the presence of OSCC with high accuracy. Cancer Prev Res; 11(8); 491–502. ©2018 AACR.
Efficacy and Safety of Dose Escalation to Adalimumab 80 mg Every Other Week in Japanese Patients with Crohn’s Disease Who Lost Response to Maintenance Therapy
Authors: Motoya Satoshi , Watanabe Mamoru , Wallace Kori , Lazar Andreas , Nishimura Yasuko , Ozawa Morio , Thakkar Roopal , Robinson Anne M. , Singh Ravi Shankar Prasad , Mostafa Nael M. , Suzuki Yasuo , Hibi Toshifumi
Published: May 2018

Background: Dose escalation is often recommended for loss of response in anti-TNFα-treated patients with Crohn’s disease (CD). This 52-week phase 3, multicenter study investigated the efficacy and safety of escalation to adalimumab 80 mg every other week (EOW) in Japanese patients with CD who lost response to maintenance adalimumab 40 mg EOW. Methods: Twenty-eight patients aged ≥15 years with moderately to severely active CD who had previously attained and subsequently lost clinical response to maintenance ada limumab received open-label adalimumab 80 mg EOW during weeks 0–50. Loss of response was defined as CD activity index (CDAI) ≥200, increases in CDAI ≥50 from minimum observed value, and C-reactive protein (CRP) ≥1 mg/dL at screening. The primary endpoint was the proportion of patients achieving a CDAI decrease ≥50 (CR-50) from baseline at week 8. Results: At weeks 8 and 52, 75.0 and 57.1% of patients achieved CR-50 and 25.0 and 35.7% achieved clinical remission (CDAI < 150), respectively; median CRP changes from baseline were −0.39 and −0.77 mg/dL, respectively. Most treatment-emergent adverse events were mild to moderate. Conclusions: Adalimumab dose escalation to 80 mg EOW improved CD activity in patients who had lost response to maintenance adalimumab, with no new safety signals. (ClinicalTrials.gov Identifier: NCT01958827.)
Using Gene Genealogies to Localize Rare Variants Associated with Complex Traits in Diploid Populations
Authors: Karunarathna Charith B. , Graham Jinko
Published: May 2018

Background and Aims: Many methods can detect trait association with causal variants in candidate genomic regions; however, a comparison of their ability to localize causal variants is lacking. We extend a previous study of the detection abilities of these methods to a comparison of their localization abilities. Methods: Through coalescent simulation, we compare several popular association methods. Cases and controls are sampled from a diploid population to mimic human studies. As benchmarks for comparison, we include two methods that cluster phenotypes on the true genealogical trees: a naive Mantel test considered previously in haploid populations and an extension that takes into account whether case haplotypes carry a causal variant. We first work through a simulated dataset to illustrate the methods. We then perform a simulation study to score the localization and detection properties. Results: In our simulations, the association signal was localized least precisely by the naive Mantel test and most precisely by its extension. Most other approaches had intermediate performance similar to the single-variant Fisher exact test. Conclusions: Our results confirm earlier findings in haploid populations about potential gains in performance from genealogy-based approaches. They also highlight differences between haploid and diploid populations when localizing and detecting causal variants.
Absence of Complications after Endoscopic Mucosal Biopsy
Authors: Johnson Brian , Basson Marc D.
Published: May 2018

Background: There is no clarity with regard to the occurrence of serious complications from EGD-driven mucosal biopsy. This is important for considering both clinically indicated procedures and mucosal sampling for research. Methods: We sought to quantify rates of serious complications from esophagogastroduodenoscopy (EGD) with biopsy. We studied 13,233 patients undergoing outpatient EGD with biopsy over 5 years in 2 North Dakota community hospitals, based on the reasoning that serious complications would cause hospitalization within 30 days. We reviewed the records of all patients with a diagnostic or procedure code or admission within 30 days after the outpatient EGD with biopsy. Results: Of the 13,233 patients who underwent outpatient EGD with biopsy, 411 were admitted within 30 days, most of them because of their underlying diagnosis. Two patients were admitted due to complications that resulted because of additional simultaneous procedures. No patient was admitted because of complications that could be ascribed to conscious sedation, upper GI endoscopic access, or mucosal biopsy. Conclusions: These data confirm that EGD biopsy is safe within community settings and suggest that the risk/benefit ratio for performing EGD biopsy for research is likely to be favorable if the research has scientific merit. Serious complications or perforation following EGD biopsy did not occur in 13,233 patients in community hospitals in North Dakota.
MiR-301a-3p Suppresses Estrogen Signaling by Directly Inhibiting ESR1 in ERα Positive Breast Cancer
Authors: Lettlova Sandra , Brynychova Veronika , Blecha Jan , Vrana David , Vondrusova Magdalena , Soucek Pavel , Truksa Jaroslav
Published: May 2018

Background/Aims: MiRNA-301a-3p is an oncogenic miRNA whose expression is associated with tumor development, metastases and overall poor prognosis. Estrogen receptor α (ERα) is one of the estrogen hormone-activated transcription factors, which regulates a large number of genes and is involved in the mammary gland development. Expression of ERα is considered to be a good indicator for endocrine therapy and breast cancer survival. Loss of ERα in breast cancer patients indicates invasiveness and poor prognosis. In this study, we focus on the regulation of ERα by miR-301a and its role in transition from estrogen-dependent to estrogen-independent breast cancer. Methods: Expression of miR-301a-3p was measured by qRT-PCR in tumor tissue samples from 111 patients with primary breast carcinoma and in mammospheres representing in vitro model of cancer stem-like cells. Dual reporter luciferase assay and complementary experiments were performed to validate ESR1 as a direct target of miR-301a-3p. The effect of miR-301a-3p on estrogen signaling was evaluated on the level of gene and protein expression and growth response to estrogens. Finally, the effect of miR-301a-3p expression on tumor growth was studied in nude mice. Results: We identified ESR1 as a direct target of miR-301a-3p. Ectopic miR-301a-3p causes a decrease in ESR1 mRNA and protein level and modulates the expression of ERα target genes in ERα positive breast cancer cells. Consistently, miR-301a-3p causes a decrease in sensitivity of MCF7 cells to 17β-estradiol and inhibits the growth of estrogen dependent tumor in nude mice. Yet, the mice tumors have significantly increased expression of genes related to cancer stem-like cells and epithelial to mesenchymal transition suggesting enrichment of the population of cells with more invasive properties, in line with our observation that miR-301a-3p expression is highly increased in mammospheres which show a decrease in estrogenic signaling. Importantly, miR-301a-3P level is also increased in primary breast cancer samples exhibiting an ER/PR negative phenotype. Conclusion: Our results confirm ESR1 as a direct target of miR-301a-3p and suggest that miR-301a-3p likely contributes to development of estrogen independence, which leads to a more invasive phenotype of breast cancer.