bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A17: Novel patient-derived xenograft (PDX) models from peritoneal metastasis of colorectal carcinoma for drug testing and biomarker analysis
Authors: Walther Wolfgang , Pachmayr Eva , Brzezicha Bernadette , Büttner Britta , Rau Beate , Stein Ulrike
Published: May 2018

Peritoneal metastasis (PM) represents a terminal tumor stage with limited therapy options for patients with colorectal cancer (CRC). To improve therapeutic efficacy and overall survival, availability of appropriate in vivo models of PM could improve the evaluation of chemosensitivity as well as identification of novel biomarkers and therapeutic targets to improve the therapeutic outcome of PM patients. In this context, we generated the first patient-derived xenograft (PDX) models of PM from CRC as platform to test chemotherapy response and to potentially analyze biomarkers.

For the PDX establishment colorectal surgical specimens were subcutaneously (s.c.) transplanted onto immunocompromised NOG mice. The engrafted tumors were transferred to NMRI nu/nu mice for further passaging. They were characterized by histopathology, immunohistochemistry, and gene expression analyses using real-time RT-PCR. Chemosensitivity of PDX models was evaluated in vivo by application of a panel of conventional chemotherapeutic and of targeted drugs.

For PDX establishment 68 CRC surgical specimens (taken from peritoneum and omentum) were transplanted, from which 22 PDX have engrafted. From those, 13 models of 10 patients have been analyzed. Their tumor doubling times ranged between 4 to 28 days. The histopathologic evaluation revealed maintenance of the original CRC histology in the PDX. The chemosensitivity testing of conventional and of targeted drugs in the 13 PM PDX models revealed the individual, diverging response of the PDX, such as for 5-FU, irinotecan, oxaliplatin, cetuximab, and erlotinib. More interestingly, different responses were observed in PDX of the omentum vs. peritoneum, which were derived from the same patient.

Our results demonstrate that this novel panel of PDX maintains the morphology of the patient tumor in early passages, reflect heterogeneous response rates, and can be used as a preclinical in vivo platform for translational studies of potential clinical use. In conclusion, this PDX panel of PM of the CRC can be used for further studies to evaluate new biomarkers and to test novel therapies or combinations for PM of CRC.

Citation Format: Wolfgang Walther, Eva Pachmayr, Bernadette Brzezicha, Britta Büttner, Beate Rau, Ulrike Stein. Novel patient-derived xenograft (PDX) models from peritoneal metastasis of colorectal carcinoma for drug testing and biomarker analysis [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 A17.
Abstract A32: Sall2 transcription factor: A novel regulator of G1-S cyclins
Authors: Hermosilla Viviana E. , Escobar David E. , Hepp Matias I. , Riffo Elizabeth N. , Salgado Ginessa , Morin Violeta , Galindo Mario , Castro Ariel F. , Pincheira Roxana , Pincheira Roxana
Published: May 2018

Spalt-like proteins are Zinc finger transcription factors present from C. elegans to vertebrates, with critical roles in development. In vertebrates, four paralogues have been identified (Sall1-4), with Sall2 being the most dissimilar member of the family. Sall2 has shown to be important for brain and eye development and–unlike its vertebrate paralogues–it has also been proposed as a tumor suppressor. Sall2 activity promotes cell cycle arrest and cell death and its expression is downregulated in several types of cancer. Despite this, very few Sall2 transcriptional targets have been identified until date.

In agreement with previous reports, characterization of primary and immortalized mouse embryonic fibroblasts (MEFs) showed a proliferative advantage of isogenic Sall2-/- vs Sall2+/+ cells. In order to identify the molecular mechanisms underlying Sall2 function during cell cycle, iMEFs were synchronized at G2/M phase with nocodazole. Flow cytometry, Western blot, and qRT-PCR analyses were performed after nocodazole release. In accordance with the role of Sall2 in promoting cell cycle arrest, a more rapid progression from G2/M to G1/S was noticed in Sall2-deficient cells, which correlates with an increased expression of Cyclin D1 (Ccnd1) and Cyclin E1 (Ccne1). Similar results were obtained in HEK293 and SKOV3 human cell lines, suggesting that Sall2 controls cell cycle progression by downregulating G1-S cyclins. Sall2-mediated repression of CCND1 and CCNE1 was confirmed by luciferase reporter assays. In addition, bioinformatic analysis led to the identification of several putative Sall2 binding sites within CCND1 and CCNE1 promoters. Sall2 binding to CCND1 and CCNE1 promoters was demonstrated by chromatin immunoprecipitation. Analysis of tissues from Sall2+/+ and Sall2-/- mice confirmed the inverse correlation between expression of SALL2 and G1-S cyclins.

Importantly, the same correlation was found in different types of tumor by analyzing publicly available databases, suggesting that Sall2-Cyclin D1-Cyclin E1 axis could be downregulated in cancer. Thus, we have identified two novel Sall2 transcriptional targets at G1-S transition.

Altogether, our findings support the role of Sall2 as a tumor suppressor, by acting as a transcriptional repressor during cell cycle.

Citation Format: Viviana E. Hermosilla, David E. Escobar, Matias I. Hepp, Elizabeth N. Riffo, Ginessa Salgado, Violeta Morin, Mario Galindo, Ariel F. Castro, Roxana Pincheira, Roxana Pincheira. Sall2 transcription factor: A novel regulator of G1-S cyclins [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 A32.
Abstract A33: Loss of Id4 initiates PIN-like lesions by maintaining stemness in mice prostate
Authors: Bostanthirige Dhanushka Hewa , Joshi Jugal , Kumar Shravan , Patel Divya , Chaudhary Jaideep
Published: May 2018

Inhibitor of differentiation 4 (Id4), a member of the helix-loop-helix family of transcriptional regulators, has emerged as a tumor suppressor in prostate cancer (PCa). Recent studies have shown that Id4 is highly expressed in the normal prostate and decreases in prostate cancer (PCa) due to epigenetic silencing. Id4 knockdown in androgen-sensitive LNCaP cells has been shown to lead to castration-resistant prostate cancer (CRPC) in vitro and in vivo. Id4-/- mice leads to underdeveloped prostate without the loss of androgen receptor (AR) expression. In this study we demonstrate that prostates from the Id4 knockout (Id4-/-) mice show PIN-like lesions, suggesting that loss of Id4 plays a major role in initiation of prostate PCa. Histology of Id4 -/- mice prostate shows more PIN lesions at 3 months and 6 months without showing clear evidence of prostate cancer. Immunohistochemical analysis demonstrated increased expression of Amacr, which is a biomarker for PIN and PCa, only in Id4-/- 3-month- and 6-month-old prostate tissue. The expression of Nkx3.1 and Pten tumor suppressor genes in Id4-/-mouse prostate was undetectable, suggesting that loss of Id4 has potential to initiate or progress to PCa. Although PTEN protein was not present in Id4-/- mice, the presence of the corresponding PTEN mRNA suggested intact transcriptional program. These results suggested that Id4 plays a role in regulating the translation of the PTEN mRNA. We are currently investigating the ID4-regulated mechanisms involved in the translational control of PTEN. The results suggested that id4-/- results in PIN lesions that are in part due to a block in Pten translation.

Sca-1 is a member of the Ly6 family of glycosyl phostidylinositol (GPI)-anchored cell surface proteins used as stem cell marker in murine prostate. According to cancer stem cell theory, stem cells in basal layer of the prostate tubules give rise to transient amplifying cells and differentiate into terminally differentiated secretory luminal epithelial cells. From the same pathway it gives rise to the tumor-promoting cells, which ultimately form prostate cancer. Sca-1 is expressed in Id4-/- mice 3-month- and 6-month-old prostate glands.

These data suggest that loss of Id4 can initiate PIN like lesions by maintaining stemness through regulating transcriptional, translational mechanism via altering the expression of PTEN, NKX3.1, C-MYC and other regulatory molecules. Currently we are investigating that regulatory mechanism, mainly focusing on mRNA interference mechanisms.

Citation Format: Dhanushka Hewa Bostanthirige, Jugal Joshi, Shravan Kumar, Divya Patel, Jaideep Chaudhary. Loss of Id4 initiates PIN-like lesions by maintaining stemness in mice prostate [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 A33.
Abstract A36: Characterizing the role of Egfr signaling in mediating the exacerbative effect of acute inflammation on tumor development in a mouse model for familial adenomatous polyposis
Authors: Li Wei , Yang Yu-Ping , Coffey Robert J.
Published: May 2018

Over the past decade a number of inducible mouse models of intestinal tumor formation have been developed to study the genetic and cellular changes that contribute to colorectal cancer (CRC) development. Among them, the Lrig1-Cre/+;Apcfl/+ mice serve as a good model to study familial adenomatous polyposis (FAP), as the targeted elimination of one copy of the Apc gene in the Lrig1-expressing (Lrig1+) intestinal progenitor cells leads to loss of heterozygosity of the remaining wild-type Apc allele in the intestinal epithelium and eventually the formation of multiple histologically advanced adenomas in the distal colon. However, adenomas formed in the Lrig1-Cre/+;Apcfl/+ mice do not progress to adenocarcinomas. In order to develop a mouse model that recapitulates the process of CRC development in its entirety, we treated the Lrig1-Cre/+;Apcfl/+ mice with the proinflammatory reagent dextran sodium sulfate (DSS) and found that a single cycle of DSS right after tamoxifen-induced initial loss of one Apc allele significantly exacerbated tumor formation in the distal colon. Interestingly, DSS-treated Lrig1-Cre/+;Apcfl/+ mice also developed highly dysplastic tumors in the proximal colon, which is normally spared from tumor formation in the untreated Lrig1-Cre/+;Apcfl/+ mice. Using a newly developed chimeric Egfr protein reporter mouse, we are interrogating the roles of dysregulated epithelial and stromal Egfr signaling in promoting tumor development in the DSS-treated Lrig1-Cre/+;Apcfl/+;EgfrEmGFP/+ mice.

Citation Format: Wei Li, Yu-Ping Yang, Robert J. Coffey, Jr. Characterizing the role of Egfr signaling in mediating the exacerbative effect of acute inflammation on tumor development in a mouse model for familial adenomatous polyposis [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 A36.
Abstract A38: Twist1-driven fatty pancreas formation facilitates pancreatitis and pancreatic ductal adenocarcinoma progression
Authors: Nguyen Thien Ly , Singh Purba , Parajuli Parash , Li Lianna , Prunier Celine , Kumar Santosh , Eragmerdi Sailaja , Ozkan Seval , Me Hao , Carmo Jussara do , Hall John , Atfi Azeddine
Published: May 2018

Fatty pancreas or pancreatic steatosis has been associated with a variety of debilitating diseases, such as obesity, diabetes, pancreatitis, and pancreatic ductal adenocarcinoma (PDAC). Currently, neither the mechanisms underlying the pathogenesis of fatty pancreas nor the physiopathologic impacts of this disorder are well established. Serendipitously, we found that conditional overexpression of Twist1 in pancreatic progenitor cells in mice resulted in fatty pancreas development, leading to pancreatic insufficiency, severe hyperglycemia, and growth retardation. Molecular and genetic studies demonstrated that Twist1 drives fatty pancreas formation by selectively reprogramming acinar cells towards the adipocyte lineage albeit without affecting islet or ductal cell fate. Moreover, loss-of-function genetic experiments demonstrated that Twist1 plays a causative role in glucose tolerance, pancreatitis genesis, and PDAC progression. Finally, high levels of Twist1 expression correlate with fatty pancreas formation in patients with pancreatitis or PDAC, implicating Twist1 as a prognostic marker and possible target for attenuating several lethal diseases associated with fatty pancreas development.

Citation Format: Thien Ly Nguyen, Purba Singh, Parash Parajuli, Lianna Li, Celine Prunier, Santosh Kumar, Sailaja Eragmerdi, Seval Ozkan, Hao Me, Jussara do Carmo, John Hall, Azeddine Atfi. Twist1-driven fatty pancreas formation facilitates pancreatitis and pancreatic ductal adenocarcinoma progression [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 A38.
Abstract A48: Ube2v1 promotes EMT and metastasis by suppression of autophagy
Authors: Shen Tong , Cai Lingdong , Liu Yuhong , Li Jianming
Published: May 2018

Ubiquitination is one of the basic post-translational modifications for cellular homeostasis. The conjugating enzyme (E2) family plays as a bridge linking the first step mediated by E1 with the final step mediated by E3 in the ubiquitin-proteasome system. However, the role of Ube2v1, one of ubiquitin-conjugating E2 enzyme variant proteins (Ube2v), in colorectal cancer (CRC) and autophagy is unclear. Here, we found that Ube2v1 is elevated in tumor samples of CRC patients and correlated with poorer survival of CRC patients. Furthermore, Ube2v1 promotes migration and invasion of CRC cells in vitro and boosts tumor growth and metastasis of CRC cells in vivo. Interestingly, Ube2v1 suppresses autophagy program and promotes EMT and metastasis of CRC cells in an autophagy-dependent pattern in vitro and in vivo. Moreover, rapamycin attenuates the enhanced in vitro migration and invasion and in vivo lung metastasis of Ube2v1 overexpression by inducing the autophagy pathway. Mechanistically, Ube2v1 increases histone H4 lysine 16 acetylation by downregulating expression of Sirt1 and epigenetically suppresses gene expression of autophagy genes in colorectal cancer. In conclusion, Ube2v1 functions as a global regulator for autophagy by epigenetically transcriptional suppression of autophagy, and consequently promotes EMT and metastasis of CRC. Our study functionally links Ube2v1, one member of E2 family in the ubiquitin-proteasome system to autophagy program in CRC progression and metastasis.

Citation Format: Tong Shen, Lingdong Cai, Yuhong Liu, Jianming Li. Ube2v1 promotes EMT and metastasis by suppression of autophagy [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 A48.
Abstract A50: Nrf2 regulates cellular behaviors and Notch signaling in oral squamous cell carcinoma cells in vivo and in vitro
Authors: Fan Hong , Sun Zheng
Published: May 2018

Oral squamous cell carcinoma (OSCC) is the most common epithelial cancer worldwide. Despite improvements and innovations in diagnostic techniques and treatments, the survival rate of patients with oral cancer has not increased. We previously demonstrated that activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a vital role in OSCC. However, the underlying mechanism of Nrf2 is unclear in OSCC. This study aimed to clarify the mechanism of Nrf2 regulating the tumorigenesis and progression of OSCC in vivo and in vitro. We confirmed that overexpression of Nrf2 promotes cell growth, migration, invasion, and colony formation in established stable Nrf2 overexpression OSCC cell lines. Quantitative real-time reverse transcription-PCR and Western blotting assays revealed that silencing the endogenous Nrf2 markedly reduced the expression levels of Notch1, the Notch1 intracellular domain (NICD1), and Hairy and enhancer of split-1 (Hes1) in OSCC cells. As expected, the transcriptional levels of Notch1 and Hes1 and the protein expression level of NICD1 and Hes1 were increased in Nrf2-overexpressing OSCC cell lines. In addition, we demonstrated that the expression of Notch1, NICD1 and Hes1were increased in the tongue tissues of 4NQO induced dysplasia and OSCC mouse model by immunohistochemistry, but their expression was lower in Nrf2-/- mice than in wild-type mice. In conclusion, Nrf2 may play a role in promoting cancer through regulating the Notch signaling pathways in oral cancer in vivo and in vitro.

Citation Format: Hong Fan, Zheng Sun. Nrf2 regulates cellular behaviors and Notch signaling in oral squamous cell carcinoma cells in vivo and in vitro [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 A50.
Abstract A51: Nicotine induces cervical lymph node metastasis of mouse tongue cancer by regulating Prx1 /EMT signaling
Authors: Wang Min , Niu Wenwen , Qi Moci , Tang Xiaofei
Published: May 2018

Oral squamous cell carcinoma (OSCC) represents one of the most common malignant neoplasms worldwide, while tobacco is a major risk factor for OSCC. Nicotine has been reported to induce EMT and promote the progression in several malignant tumors. Our previous study showed that upregulation of Peroxiredoxin 1(PRX1) expression was observed and associated with nicotine-induced oxidative stress in OSCC. However, the effects of nicotine and the underlying molecular mechanisms on the development of OSCC metastases are not completely understood. Here, we established the cervical metastasis mouse models of tongue cancer by orthotopic transplantation of OSCC cell line siControl CAL 27 cells and siPRX1 CAL 27 cells labeled with GFP into the tongues of nude mice, in order to investigate the roles and mechanisms of nicotine in OSCC metastasis. Fluorescence stereomicroscopy was used to confirm the tumor formation and the development of cervical metastases, which the tumor cells showed distinct green fluorescence in mouse tongues and lymph nodes. The results showed that at day 13 after CAL 27 cell implantation, nicotine promoted OSCC growth in the tongues and metastatic rates of cervical lymph node in mice compared with control. Histologic examination and immunohistochemical staining with anti-keratin antibody further confirmed tumor formation and lymph node metastases. Nicotine treatment was shown to promote the downregulation of expression levels of E-cadherin, and upregulation of vimentin and Snail expression in tongues and lymph nodes, compared with those in the control mice. PRX1 knockdown led to the reduction in the metastasis rate, upregulation of E-cadherin expression, and downregulation of vimentin and Snail expression in tongues and lymph nodes. No significant differences were seen in the cervical lymph node metastatic rates and the expression of EMT-related markers between nicotine-treated and vehicle-treated mice after PRX1 knockdown. These results suggest that nicotine may induce cervical lymph node metastases through the regulation of Prx1/EMT signal pathway during OSCC pathogenesis. PRX1 plays a critical role in nicotine-induced metastasis of OSCC.

Citation Format: Min Wang, Wenwen Niu, Moci Qi, Xiaofei Tang. Nicotine induces cervical lymph node metastasis of mouse tongue cancer by regulating Prx1 /EMT signaling [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 A51.
Abstract B06: A SOX9+ bile duct progenitor as a cell of origin of hepatocellular carcinoma
Authors: Viatour Patrick
Published: May 2018

Hepatocellular carcinoma (HCC) is the most frequent form of liver cancer and its associated mortality is increasing. Most HCC patients are diagnosed at an advanced stage of the disease, which is not eligible for curative surgery and for which efficient drugs remain elusive. Consequently, the prognosis of these patients is particularly poor, begging for a revolution in our therapeutic approach of the disease.

Our in-depth understanding of HCC etiology suggests that patients at risk could be regularly screened for the early detection and treatment of nascent neoplastic lesions. This strategy requires a detailed knowledge of the early events that initiate HCC since their nature shapes the features of the developing lesions. However, the identity of cells that can serve as a cell of origin for HCC as well as the molecular events that transform them remain unknown, hampering the development of an early-intervention strategy.

To address this important gap in our knowledge, we have taken advantage of a tractable model of HCC initiated upon Rb family loss of function, which is an almost universal event in cancer and particularly in HCC. The Cre/Lox-mediated inactivation of Rb family genes in distinct liver cell populations (cholangiocytes, hepatocytes, and various populations of bipotential and committed progenitors) reveals that most tested cell types, while displaying aberrant cell cycle activity, are resistant to transformation upon Rb pathway alteration. However, Rb family inactivation in Sox9-expressing bile duct progenitor cells initiates HCC that recapitulates the human disease. Interestingly, these committed cholangiocyte progenitors rapidly lose their canonical markers to adopt markers that are specific of the hepatocyte lineage, suggesting that Rb gene family inactivation potentiates their cellular plasticity. Importantly, analysis of human HCC array reveals that expansion of Sox9-expressing cells is a common feature of premalignant lesions and early-stage HCC.

Despite its almost universal alteration in cancer, our mouse genetic approach demonstrates that only rare cell populations are susceptible to transformation upon Rb pathway inactivation. In addition, our data show that a cholangiocyte-restricted progenitor population can serve as the cell of origin for a hepatocyte-based type of cancer. This model will enable us to deconstruct the molecular mechanisms that initiate and drive early HCC development and ultimately allow us to shift the clinical management of the disease towards its early steps.

Citation Format: Patrick Viatour. A SOX9+ bile duct progenitor as a cell of origin of hepatocellular carcinoma [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 B06.
Abstract B10: The polyploid state plays a tumor-suppressive role in the liver
Authors: Zhang Shuyuan , Zhou Kejin , Luo Xin , Li Lin , Nguyen Liem , Zhang Yu , Tarlow Branden , Siegwart Daniel , Zhu Hao
Published: May 2018

Most cells in the liver are polyploid, but the functional role of polyploidy is unknown. Polyploidization normally occurs through cytokinesis failure and endoreduplication around the time of weaning. To interrogate the function of polyploidy while avoiding irreversible manipulations of essential cell cycle genes, we developed multiple orthogonal mouse models to transiently and potently alter liver ploidy. Premature weaning, as well as in vivo knockdown of E2f8 or Anln, allowed us to toggle between diploid and polyploid states. While there was no impact of ploidy alterations on liver function, metabolism, or regeneration, hyperpolyploid mice suppressed and hyperdiploid mice accelerated tumorigenesis in mutagen and high fat induced models. Mechanistically, the diploid state was more susceptible to Cas9-mediated tumor suppressor loss but was similarly susceptible to MYC oncogene activation, indicating that ploidy differentially protected the liver from distinct genomic aberrations. Our work suggests that polyploidy evolved in part to prevent malignant outcomes of liver injury.

Citation Format: Shuyuan Zhang, Kejin Zhou, Xin Luo, Lin Li, Liem Nguyen, Yu Zhang, Branden Tarlow, Daniel Siegwart, Hao Zhu. The polyploid state plays a tumor-suppressive role in the liver [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 B10.
Abstract B32: Targeting WNT signaling in vivo via Tankyrase inhibition
Authors: Schatoff Emma M. , Leach Benjamin I. , Foronda Miguel , Zafra Maria Paz , Dow Lukas
Published: May 2018

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Approximately 95% of CRCs show hyperactive WNT signaling, yet there are no targeted therapies that effectively suppress the WNT pathway. The majority (~80%) of these tumors harbor a mutation in APC, a scaffold component of the “destruction complex,” which is a critical negative regulator of WNT.

Using genetically defined mouse models of CRC, we recently showed that restoring Apc function can induce WNT suppression and rapid and sustained disease regression. While there is no way to restore normal APC protein in human CRCs, it may be possible to restore the function of the APC-associated destruction complex by inhibiting Tankyrase (TNKS) enzymes. Tankyrase inhibitors have been shown to stabilize AXIN, prevent degradation of the destruction complex, and decrease levels of WNT signaling. While in vitro studies have shown promise, it is unclear whether TNKS inhibition could provide a therapeutic benefit in vivo. Some published work reports significant antitumor activity, while others suggest overt dose-limiting toxicity. Thus, while TNKS inhibition holds significant potential, it is not clear whether TNKS enzymes are a viable target for CRC therapy.

To circumvent the limitations of drug delivery, potency, and specificity, we generated mice with inducible, fluorescent reporter-linked shRNAs targeting Tnks and its redundant family member Tnks2. Here we show that potent, simultaneous shRNA-mediated knockdown of both genes is sufficient to stabilize Axin in vivo, similar to treatment with a pan-TNKS inhibitor, XAV939. We show that Tnks1/2 knockdown stabilizes Axin and suppresses WNT signaling, but surprisingly, does not disrupt intestinal architecture. Importantly, Tnks1/2 silencing blocks hyperproliferation and tumor development in mice following Apc disruption. In contrast to current studies using small-molecule TNKS inhibitors, our work suggests that there is a viable therapeutic window of TNKS1/2 inhibition in vivo, and that this strategy enables control of hyperactive WNT signaling in CRC and other WNT-associated cancers.

Citation Format: Emma M. Schatoff, Benjamin I. Leach, Miguel Foronda, Maria Paz Zafra, Lukas Dow. Targeting WNT signaling in vivo via Tankyrase inhibition [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 B32.
Abstract B42: Targeting cancer cell CCR2 enhances synergistic immune surveillance in breast cancer
Authors: Fein Miriam R. , He Xue-Yan , Almeida Ana S. , Pommier Arnaud , Bružas Emilis , Eberhardt Anaïs , Wilkinson John Erby , Santos Camila dos , Egeblad Mikala
Published: May 2018

High expression of the C-C chemokine receptor type 2 (CCR2) in tumor samples and serum correlates with poor prognosis in human breast cancer, which has sparked interest in targeting the CCR2 pathway for therapeutic benefit. Importantly, a human CCR2 inhibitor (PF-04136309) has been investigated in clinical trials, and is currently being studied in a phase 1b/2 trial for pancreatic cancer (NCT02732938). Previous studies have focused on the protumor effects of CCR2 signaling in inflammatory monocytes. However, CCR2 is also expressed in breast cancer cells, but its potential function in cancer cells is poorly understood.

To determine the specific roles of CCR2 in cancer and host cells, respectively, we established an orthotopic breast cancer mouse model by injecting primary cancer cells from MMTV-PyMT; Ccr2+/+ or MMTV-PyMT; Ccr2-/- mice into the mammary glands of wide-type or Ccr2 null hosts. In this cancer model, deleting Ccr2 in host cells, including monocytes, did not alter tumor growth. However, when tumor cells had lost Ccr2, immune surveillance was much more efficient, with greater infiltration and expansion of cytotoxic CD8+ T cell lymphocytes (CTLs) that efficiently recognized and destroyed the cancer cells, resulting in significant inhibition of tumor growth. Consistently, the delayed tumor growth of Ccr2 null cancer cells was fully reversed when these same cancer cells were transplanted into athymic (immunodeficient) mice. The reduced growth of tumors derived from Ccr2-/- cancer cells was associated with upregulation of IFN-γ response genes and genes involved in MHC class I presentation, as well as decreased expression of checkpoint inhibitor PD-L1 in cancer cells. Finally, greater infiltration of CD103+ dendritic cells (DCs) in Ccr2-/- tumor microenvironment also contributed to increased CTL function by cross presentation.

Taken together, our results show that CCR2-expressing breast cancer cells orchestrated global changes in the infiltration of CTLs and DCs, leading to effective immune suppression. This suggests that CCR2 may be an immunotherapeutic target in breast cancer.

Citation Format: Miriam R. Fein, Xue-Yan He, Ana S. Almeida, Arnaud Pommier, Emilis Bružas, Anaïs Eberhardt, John Erby Wilkinson, Camila dos Santos, Mikala Egeblad. Targeting cancer cell CCR2 enhances synergistic immune surveillance in breast 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 B42.
Abstract B46: Varying the inoculation site of mouse syngeneic tumors can result in aberrant inclusion of lymph node tissue at tumor harvest
Authors: Clift Renee , Blouw Barbara , Zimmerman Susan , Rosengren Sanna , Thompson Curt , Thompson Benjamin
Published: May 2018

In recent years, growing interest in immunotherapies for the treatment of cancer has led to increased reliance on murine syngeneic tumor models for preclinical study in immunocompetent animals. These studies typically examine changes in the quantities and phenotypes of tumor-infiltrating immune cells; thus, it is crucial to distinguish between these cells and extratumoral immune cells during tumor harvest. Here, we show that 4T1 breast tumors inoculated in mammary fat pads (MFP) numbers 4 or 9 (4/9) contained greater frequencies of B cells and naïve T cells than tumors inoculated in MFP numbers 5 or 10 (5/10). Immunohistochemical analysis for B-cell presence demonstrated that MFP 4/9 tumors encroached on, and often encapsulated, inguinal lymph nodes, such that lymph node tissue was unknowingly collected during tumor harvest. This prevented accurate enumeration and phenotyping of infiltrating immune cells by flow cytometry, as the majority of lymphocytes in the affected samples derived from lymph nodes, and had not infiltrated the tumor per se. We observed the same phenomenon in peritibial tumors using immunohistochemical analysis, which began to encapsulate popliteal lymph nodes at large tumor volumes (>1500 mm3). Our data highlight the importance of choosing an appropriate inoculation site for obtaining accurate and consistent results when evaluating immune cell infiltration in syngeneic tumor models.

Citation Format: Renee Clift, Barbara Blouw, Susan Zimmerman, Sanna Rosengren, Curt Thompson, Benjamin Thompson. Varying the inoculation site of mouse syngeneic tumors can result in aberrant inclusion of lymph node tissue at tumor harvest [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 B46.
Abstract B52: Brusatol inhibits oral squamous cell carcinoma cells by targeting glycolytic metabolism
Authors: Zhang Guilian , Su Ying , Chen Suhong , Zhang Xinyan
Published: May 2018

Brusatol is a natural terpenoid that is isolated from the Brucea javanica plant, a medicine plant distributed widely throughout Asia, and its bitter fruits have been used traditionally in medicine for treating various ailments and controlling some pests. Brusatol has recently been shown to be capable of inducing a variety of biologic effects, including a potential antitumor effect. The goal of this study was to investigate the role of brusatol in oral squamous cell carcinoma (OSCC) cells and its mechanism. Brusatol treatment had broad effects against oral cancer cells in vitro including inhibition of proliferation, colony formation, cell migration and invasion, and induction of apoptosis. Mechanism studies showed that brusatol inhibited glucose uptake and lactate secretion and glycolytic pathway key enzymes HK and PK activity in vitro. Brusatol inhibited glycolysis, glycolytic capacity, and reserve capacity by Seahorse XF glycolysis stress test assay. In vivo study showed that brusatol suppresses tumor growth in a nude mouse xenograft model by inhibiting cell proliferation and angiogenesis and by inducing apoptosis. Glycolysis-related genes were also deceased in the nude mice xenografts. Taken together, these data clearly indicated that brusatol is a promising chemotherapeutic agent for OSCC treatment.

Citation Format: Guilian Zhang, Ying Su, Suhong Chen, Xinyan Zhang. Brusatol inhibits oral squamous cell carcinoma cells by targeting glycolytic metabolism [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 B52.
Abstract IA15: Normal and cancer stem cells in multistage carcinogenesis
Authors: Balmain Allan
Published: May 2018

Mouse models of cancer have been instrumental in the development of our understanding of the processes that drive multistage carcinogenesis from the initiation stage to metastasis. In particular, tumors induced in mice by exposure to chemicals that act as mutagens or tumor promoters replicate many of the biologic and genetic features of multistage cancer in human populations. Such models often have a high burden of point mutations and gene copy number changes similar to human tumors of the lung, colon, or skin that are associated with exposure to exogenous environmental agents. These are important features that contribute to tumor heterogeneity—a major cause of drug resistance and poor response to therapy in human cancer patients. The availability of mouse models of tumors with a high mutation burden also offers possibilities for development of immunotherapy approaches that are dependent on expression of novel tumor antigens resulting from carcinogen-induced mutations in tumor DNA.

Initiation of chemical carcinogenesis in the mouse is frequently caused by point mutations in genes of the Ras family. The nature of the initiating Ras mutation depends on the carcinogen used, but a similar “mutation signature” is seen throughout the genome of the initiated cell. Tumor cells, however, continually acquire additional new genetic alterations, leading to the emergence of multiple, genetically distinct tumor subclones. By combining the 4-color lineage tracing Confetti mouse with a chemical carcinogenesis model of skin cancer, we have investigated clonal and evolutionary dynamics at every stage of chemical carcinogenesis, from the initiated cell to benign tumors, malignant carcinomas, and ultimately to distant metastases. These studies reveal distinct patterns of clonal evolution at different stages of progression. The growth of subclones within tumors is driven by a stem cell population marked by expression of the Lgr6 gene—a known marker of normal skin stem cells and mediator of Wnt signaling in the epidermis. The use of mouse models for identification of patterns of clonal heterogeneity, and the drivers of clonal growth from cancer stem cells, may offer new possibilities for prevention or treatment of squamous carcinomas.

Citation Format: Allan Balmain. Normal and cancer stem cells in multistage carcinogenesis [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 IA15.
Abstract IA16: The global proteome and phospho-proteome of K-Ras mutant tissues
Authors: Haigis Kevin
Published: May 2018

K-Ras is the most commonly mutated oncogene in cancer, and it plays a predominant role in the pathogenesis of cancers of the pancreas, colon, and lung. Mutationally activated K-Ras influences cellular behaviors through broad and complex effects on downstream signal transduction pathways. In an effort to understand the molecular mechanisms underlying the oncogenic properties of mutant forms of K-Ras, we have used multiplexed mass spectroscopy (MS) to quantify proteome-wide changes in protein phosphorylation in primary mouse tissues that are engineered to express mutant K-Ras, either alone or in combination with mutations in other cancer genes. This multidimensional dataset highlights the context dependence of K-Ras signaling because the significant changes in protein abundance and/or phosphorylation due to activation of K-Ras are highly dependent upon both tissue context and cooperating mutations. The dataset also paints a complex picture of signaling downstream of K-Ras within a given tissue, as phosphorylation of many proteins in known Ras effector pathways (i.e., MAPK and PI3K) are unaffected or downregulated by mutationally activated K-Ras. Overall, this study provides an unprecedented view of K-Ras signaling on a global scale and reveals a variety of novel insights into the signal transduction properties of mutant K-Ras alleles.

Citation Format: Kevin Haigis. The global proteome and phospho-proteome of K-Ras mutant tissues [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 IA16.
Abstract IA21: Interrogating cancer drivers and dependencies using non-germline mouse models
Authors: Lowe Scott W.
Published: May 2018

Cancer is a heterogeneous disease involving various genetic and epigenetic alterations that initiate and maintain the disease. Our laboratory is interested in understanding how such alterations contribute to tumorigenesis, alter treatment response, and create vulnerabilities that may be targeted therapeutically. To interrogate cancer in vivo, we have developed a range of non-germline mouse models that enable a wide variety of cancer genotypes to be produced in a fraction of the time and cost of traditional germline methods. Approaches vary depending on the particular question, and can involve genetic manipulation and retransplantation of tissue stem cells and/or organoid cultures, the generation of multi-allelic ES cells and subsequent use in chimeric mice, and direct somatic engineering of mutations in particular tissues. Additionally, we have incorporated RNAi and CRISPR/Cas9 technologies to expedite our ability to study gene function in these models. Collectively, the combination of these tools has allowed us to identify and characterize new cancer drives using one-by-one or multiplexed approaches, and to perform rapid in vivo validation of “hits” from functional genomic screens. Examples of each method and approach will be presented.

Citation Format: Scott W. Lowe. Interrogating cancer drivers and dependencies using non-germline mouse models [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 IA21.
Abstract IA28: Using mouse models to develop therapies for Ras-driven cancers
Authors: Cichowski Karen
Published: May 2018

Selective kinase inhibitors have changed the standard of care in cancers that are driven by oncogenic kinases. Nevertheless, therapeutic effects are often temporary and it is becoming increasingly apparent that the majority of human malignancies will not be eradicated by a single drug. Ras-driven cancers are particularly problematic; agents that target individual Ras effectors are ineffective and successful therapeutic combinations have not yet been identified. Therefore, it is imperative that we rationally conceptualize and test new therapeutic combinations that either function to suppress orthogonal pathways in tumors or converge on a specific cancer-cell vulnerability. Mouse models provide a powerful tool to identify and evaluate such combinations. Not only can they be used to identify critical therapeutic targets and dissect therapeutic mechanisms of action, but they can also directly inform clinical trials. In this presentation therapeutic strategies that (co)target kinases, epigenetic regulators, and immunoregulatory proteins will be discussed. Importantly, the mechanisms by which various combinations function reveal nodal points of convergence between these distinct pathways and reveal new vulnerabilities that can be targeted in cancer.

Citation Format: Karen Cichowski. Using mouse models to develop therapies for Ras-driven cancers [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 IA28.
Abstract PR01: Modeling colorectal cancer in vivo through CRISPR-based genome editing
Authors: Han Teng , Schatoff Emma M. , Murphy Charles , Zafra Maria Paz , Wilkinson John , Elemento Olivier , Dow Lukas E.
Published: May 2018

In addition to activating and inactivating mutations in protein coding genes, cancer cells commonly show gross structural abnormalities in their genomes. These include deletions, duplications, inversions, and translocations. Unfortunately, conventional gene targeting- and RNAi-based approaches are not easily applied to study chromosome rearrangements. To enable this, we developed flexible CRISPR-based in vivo models systems that drive the generation of targeted genomic breaks, and the induction of gross chromosomal aberrations, without the need for viral delivery of CRISPR components. Using this approach we have produced novel transgenic systems to recapitulate two recurrent genomic rearrangements observed in human colorectal cancer and provide the first evidence that these events are sufficient to initiate tumor development. Further, we show that these tumors, while histologically similar to Apc mutant CRC, are molecularly distinct and are exquisitely sensitive to therapies targeting the Wnt pathway. We are now using this and other genome-editing platforms to systematically investigate the role of other recurrent genetic alterations in GI malignancies.

Citation Format: Teng Han, Emma M. Schatoff, Charles Murphy, Maria Paz Zafra, John Wilkinson, Olivier Elemento, Lukas E. Dow. Modeling colorectal cancer in vivo through CRISPR-based genome editing [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 PR01.
Abstract PR08: Altered nucleolar trafficking of the Blm helicase in the mouse reduces size, increases DNA damage and tumor susceptibility, and facilitates premature aging
Authors: McIlhatton Michael , Fernandez Max , Acharya Samir , Coppola Vincenzo , Groden Joanna L.
Published: May 2018

Bloom's syndrome (BS) is a recessive human chromosome breakage disorder caused by mutations in the recQ-like helicase BLM, sometimes known as RECQL2. Its clinical phenotype invariably includes male infertility, dwarfism, cancer susceptibility, and growth defects related to now characterized biochemical functions in DNA repair and rDNA transcription. The BLM protein includes two serines within a highly conserved carboxy-terminal nuclear localization sequence (NLS) that are critical for dynamic nucleolar trafficking of BLM where it facilitates rRNA transcription through direct interactions with RNA polymerase I and topoisomerase 1. CRISPR/Cas9-directed gene editing techniques generated homozygous murine models with these two conserved amino acids substituted by aspartic acids or alanines, and Blm proteins that were invariably excluded (DD) or constitutively localized (AA) within the nucleolus. Both protein isoforms retain biochemical functions and nuclear localization; BLM-/- cells transfected with the DD transgene display increases in nucleolar DNA damage compared to those transfected with the wild-type gene. BlmDD/DD mice with excluded Blm, but not BlmAA/AA mice, are smaller than their wild-type littermates at 8, 12, and 16 weeks of age; BlmDD/DD mice develop significantly more adenomas than littermates when crossed to the ApcMin/+ model of intestinal tumor formation. Finally, BlmDD/DD mice, but not their wild-type littermates, display signs of premature aging by one year of age, with weight loss, changes in coat color and quality, and spontaneous tumor formation. Our studies demonstrate functions for dynamic Blm nucleolar localization in maintaining stability of both the nucleolar and non-nucleolar genomes. A role for Blm/BLM in the prevention of aging is also exposed by these mouse models as only RecqL4 (RECQL4 mutations lead to Rothmund-Thomson syndrome in the human), but not Wrn/RecqL3 (WRN mutations lead to Werner's syndrome in the human), localizes to the murine nucleolus. Both Werner's syndrome and Rothmund-Thomson syndrome are associated with DNA repair deficiency, tumor susceptibility, and premature aging in the human. Our murine models also permit the definition of amino acid sequences and mechanisms that target or exclude proteins from the nucleolus.

This abstract is also being presented as Poster A30.

Citation Format: Michael McIlhatton, Max Fernandez, Samir Acharya, Vincenzo Coppola, Joanna L. Groden. Altered nucleolar trafficking of the Blm helicase in the mouse reduces size, increases DNA damage and tumor susceptibility, and facilitates premature aging [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 PR08.
Power to Health Reporters: Health Literacy as a Tool to Avoid Pressures from News Sources
Authors: Lopes Felisbela , Araújo Rita
Published: May 2018

The second biggest Legionnaires’ disease outbreak worldwide occurred in Portugal in 2014. It was classified by the WHO as a “great public health emergency,” and it was subject to a unique media coverage in Portugal. The media coverage of this outbreak lasted for 2 weeks, which is not very common in similar cases, and it was characterized by the control of information by official sources. These were put together in a joint task force that disseminated all information. Nonetheless, they did not generate a hegemonic discourse which is usually characteristic of power elites. That happened mostly due to the promotion of health and risk literacy. Through infographics, descriptive maps, and questions and answers, the media were able to generate an alternative discourse to that of official sources. That was the basis of a unique media coverage.