bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract IA06: [Advocate Abstract:] A Tale of Two Cases
Authors: Lima Mayra A.
Published: March 2017

Breast Cancer is the most common type amongst women and the second leading cause of cancer deaths in the United States. We know from research that the relative 5 year survival rate for women diagnosed with early stage breast cancer is 98% compared to 23% for late stage. Disparities in cancer come in many shapes and forms and research has shown that they can affect outcomes. The three common types of disparities are: low socioeconomic status; cultural issues, and social biases. These are not exclusive of each other, and often appear in combination.

In South Florida we are blessed with a diverse community with Hispanics, African Americans, Native Americans, and people of Caribbean background, creating a rich cultural ambience. These cultures and ethnicities have many common characteristics such as the love and support of family, beautiful music and delicious foods. Unfortunately, they also have a high incidence of low socioeconomic status, high incident of advanced cancer at diagnosis, and high mortality rate from a diagnosis of cancer.

There are important lessons that can be learned from the rich and unique character of breast cancer care in South Florida.

Citation Format: Mayra A. Lima. [Advocate Abstract:] A Tale of Two Cases. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr IA06.
Abstract IA07: Adherence to oral chemotherapy in children with Acute Lymphoblastic Leukemia
Authors: Bhatia Smita
Published: March 2017

There is persuasive evidence that poor adherence to oral 6MP in children with ALL is prevalent and is associated with relapse. Carefully conducted studies using objective methods to monitor adherence (MEMS Caps) have yielded a critical level of adherence associated with an increased risk of relapse (~95%). These studies have demonstrated that the prevalence of non-adherence (adherence rate <95%) is 44% among children with ALL, and that 47% of the relapses observed among children entering remission in 1st CR are attributable to non-adherence. Vulnerable sub-populations at high risk of non-adherence include: older age (12-21 vs. <12); non-white race/ethnicity (Hispanics, African Americans and Asians); low annual household income/low parental education; household structure (single mother/multiple children); and absence of a routine surrounding pill taking. The most common self-reported reason for missing 6MP doses is forgetting to take medications. On the other hand, the most common facilitator for not missing 6MP doses is parental vigilance. These observations have informed a randomized clinical trial to enhance adherence to oral 6MP; this trial is currently enrolling patients. The comprehensive intervention package consists of a multimedia interactive patient/parent education program (MIPE), and physician-initiated web-based medication scheduling that translates into printed schedules and daily text-message reminders to prompt directly supervised therapy (DST) by the designated parent. We are studying the impact of this intervention package (IP) vs. MIPE alone (Edu) to improve adherence to oral 6MP in children with ALL. This trial is open at 89 sites. Of the 810 patients approached, 478 patients enrolled (participation rate: 59%). We anticipate reaching the target enrollment of 608 by June, 2017, with analyses completed by December, 2017.

Citation Format: Smita Bhatia. Adherence to oral chemotherapy in children with Acute Lymphoblastic Leukemia. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr IA07.
Abstract IA08: Pharmacogenomics of anticancer agent toxicity in different populations
Authors: Dolan M. Eileen
Published: March 2017

With over 28 million cancer survivors worldwide, there is a heightened awareness of the long-term toxicities resulting from treatment and their impact on quality of life in cancer survivors. Understanding genomic factors contributing to cancer related symptom burden would be highly beneficial to cancer patients. Preclinical studies using HapMap lymphoblastoid cell lines have indicated inter-individual and inter-population differences in cellular sensitivity to chemotherapeutics (as a representation of toxicity). The differences can be explained, to some extent, by variation in: 1) genetics; 2) gene expression and; 3) modified cytosines. Although this preclinical model provides a means to elucidate the genetic, transcriptomic and molecular underpinnings of population differences in sensitivity to chemotherapeutics, lymphoblastoid cell lines do not represent tissues of toxicity (peripheral neurons, kidney, cardiac cells, hair cells). To this end, clinical genome wide association studies (GWAS) of chemotherapeutic toxicity have been conducted. Unfortunately, most patients in these studies have been white subjects of European descent with an under representation of minorities. Since it is known that allele frequencies of polymorphisms within important pharmacogenes differ among different populations, there is a need to perform GWAS in under represented populations. Unfortunately, GWAS in oncology continue to widen the disparity gap because of the lack of knowledge of genetic variants that put minority populations at risk for chemotherapeutic toxicity.

Citation Format: M. Eileen Dolan. Pharmacogenomics of anticancer agent toxicity in different populations. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr IA08.
Abstract IA35: Community Health Workers Navigating Patient through Clinical Trials
Authors: Ramos-Calderon Jackie
Published: March 2017

The Promotores/Community Health Worker (P/CHW) model has been highlighted as an effective means of promoting healthy communities and addressing health disparities among at-risk groups not only in the United States but globally. In particular, integration of P/CHWs into local government programs has been considered as a viable means for advancing community resilience, preventive care and wellness. P/CHWs navigate vulnerable populations into the health care system in a timely manner, thereby improving health outcomes overall.

Many P/CHWs have experienced system and cultural barriers on a personal level. This firsthand knowledge provides them with the proper tools to help eliminate the barriers that prevent people from accessing quality health care. They have access to information about local resources, are trained in a culturally and linguistically proficient manner on health issues and are able to navigate those needing follow up care. People who are low-income, elderly, racial/ethnic minorities, women and those residing in rural areas endure serious challenges when diagnosed with chronic diseases caused by lack of information and means of communication. P/CHWs are routinely needed to assist communities and organizations with outreach activities (education to screening), and in-reach (navigation from diagnosis through treatment). These same individuals can be trained on clinical research and used as clinical trials navigators. P/CHWs are the answer to addressing the problem of recruitment and retention of underserved populations as participants in clinical trials.

Citation Format: Jackie Ramos-Calderon. Community Health Workers Navigating Patient through Clinical Trials. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr IA35.
Abstract A28: Challenging new epigenetic vulnerabilities in human metastatic melanoma PDXs
Authors: Bossi Daniela , Cicalese Angelo , Dellino Ivan Gaetano , Luzi Lucilla , Punzi Simona , D'Alesio Carolina , Cavallaro Elena , Minucci Saverio , Pelicci PierGiuseppe , Lanfrancone Luisa
Published: March 2017

Metastatic melanoma is one of the most aggressive cancers, refractory to most of the current therapies in its late stage. Melanoma is characterized by a strong molecular heterogeneity, and patients can be stratified in different subtypes according to genetic alterations. Despite the approval of new targeted drugs, patient treatment produces only partial responses and frequent and rapid relapses, mostly due to increased resistance. Mounting evidence highlights the necessity to better stratify melanomas on the basis of altered molecular pathways and to define new specific and effective tailored therapies. Our main goal is the genetic and functional characterization of metastatic melanomas aimed to generate new predictive and prognostic biomarkers and to identify new potential “druggable” candidates involved in melanoma progression.

We have generated a series of human-in-mouse melanoma models, by xeno-transplantation of a cohort of human melanoma samples in immune-compromised mice. Our patient-derived xenografts (PDXs) faithfully recapitulate the heterogeneity of the original tumors at phenotypic and genetic level. Taking advantage of our model, we performed the first in vivo genetic screen on patient-derived tumors, using metastatic NRAS- and BRAF-mutant melanomas and targeting chromatin genes (~240). Our screens revealed unprecedented numerosity of tumor drivers (~50% of tested genes) and unexpected functional heterogeneity among patients (~60 drivers per tumor; <15% in common). Tumor drivers, however, were not activated by somatic mutations in the same patients. Several genes have been validated in vivo and then characterized in vitro on primary cultures derived from the patients' cells. We analysed underlying molecular mechanisms of one of the identified drivers, the Histone-lysine N-methyltransferase KMT2D, and showed that it promotes tumorigenesis by dysregulating a subset of transcriptional enhancers and genes involved in cell migration.

Citation Format: Daniela Bossi, Angelo Cicalese, Ivan Gaetano Dellino, Lucilla Luzi, Simona Punzi, Carolina D'Alesio, Elena Cavallaro, Saverio Minucci, PierGiuseppe Pelicci, Luisa Lanfrancone. Challenging new epigenetic vulnerabilities in human metastatic melanoma PDXs. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A28.
Abstract B05: Patient-derived GBM tumors versus patient-derived primary cells and GBM cell lines: lessons from microRNA profiling
Authors: Ofek Paula , Dromi Nir , Yerushalmi Noga , Kredo-Russo Sharon , Grossman Rachel , Ram Zvi , Satchi-Fainaro Ronit
Published: March 2017

Glioblastoma multiforme is a very heterogeneous tumor, highly infiltrative, angiogenic and resistant to standard therapeutic intervention. Experimental models currently used in research are mostly based on cancer cell lines, which are grown in culture for many generations and have lost many essential biological characteristics. In consequence, the xenograft tumor models derived from those cells do not maintain genomic and phenotypic characteristics present in the original tumor. It is questionable whether these artificial preclinical models can serve as reliable platforms to select the lead candidate for a novel therapeutic approach.

We utilized miRNA expression patterns to evaluate the clinical relevance of some of the currently available experimental models of GBM, searching for similarities and differences in miRNA expression levels between freshly isolated tumors, patient-derived primary cells and GBM cell lines grown in culture. The study included 22 formalin-fixed paraffin-embedded (FFPE) tumors from glioblastoma resections. Those were divided into two groups of Short Term Survivors (STS, survived up to 3 months from initial diagnosis; n=12) and Long Term Survivors (LTS, survived more than 3 years from initial diagnosis; n=10).We further tested 6 patient-derived primary cells, and 5 ATCC human GBM cell lines widely used in preclinical research. Two of the cell lines included dormant and fast-growing variants previously developed in our laboratory to resemble LTS and STS phenotypes, respectively. Samples were loaded on custom microRNA (miR) arrays, including 2172 known miRNAs (miRBase 19).

We found several miRNAs that were upregulated in the STS samples while others exhibited higher expression levels in the LTS samples.

Both GBM cell lines and patient-derived primary cells exhibited a miRNA profile which was very different from patient samples. Brain miRNAs used as brain markers, such as hsa-miR-124-3p), show relatively low expression levels in both patient-derived primary cells and commercial cell lines but are highly expressed in tumors.

We concluded that GBM experimental models must be reevaluated and pre-clinical findings derived from long-established and commonly used in vitro and in vivo models should be further validated in patient-derived models that are more suitable to evaluate the potential clinical relevance of new therapeutics.

Citation Format: Paula Ofek, Nir Dromi, Noga Yerushalmi, Sharon Kredo-Russo, Rachel Grossman, Zvi Ram, Ronit Satchi-Fainaro. Patient-derived GBM tumors versus patient-derived primary cells and GBM cell lines: lessons from microRNA profiling. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B05.
Abstract B06: Studying cytarabine resistance through PDX models in acute myeloid leukemia
Authors: Farge Thomas
Published: March 2017

The major therapeutic barrier in acute myeloid leukemia (AML) is chemotherapy resistance. AML cells resistant to conventional chemotherapy targeting DNA synthesis are thought to be enriched in quiescent leukemic stem cells (LSCs). In order to better understand chemotherapy resistance in AML, we analyzed the response to cytarabine (AraC) through patient-derived xenograft (PDX) models with 20 primary AML patient specimens from two clinical sites and in the context of a French “Innovative models initiative” (IMODI) program. After confirming AML engraftment, highly immunodeficient NOD/LtSz-scid IL2Rγc null (NSG) mice were treated with AraC administered IP for 5 days as a single agent at 60 mg/kg daily, which correlates with human dosing. In all mice treated with this regimen, there was a significant but variable cytoreductive effect (4- to 46-fold reduction of tumor cell burden; 2- to 13-fold induction of apoptosis) at 3 days post-treatment. This in vivo AraC response in PDX models has been compared to clinicobiological data of their matched patients (including overall survival, FAB classification, and age at diagnosis). Furthermore, residual leukemic cells (RLCs), surviving after in vivo AraC treatment, have been characterized for their cell surface phenotype, stem cell frequency, cell cycle and metabolic status. Gene expression of RLCs from three different PDX models showed an enrichment of genes involved in inflammatory, immune and stress/ROS responses. When tested in three independent cohorts of AML patients (Verhaak et al. 2009; TGCA. 2011; Metzeler et al. 2011), the down-regulated gene signature is associated with an unfavorable prognosis in patients treated with intensive chemotherapy. Altogether, these results suggest a novel model of AraC chemotherapy resistance uncovering the control of the oxidative and mitochondrial energy metabolism in vivo and the relevance of PDX models for clinical investigations and new preclinical drug assessment. Further studies of the role of immune and stromal microenvironment will be assessed in this model to extend our findings in a more relevant setting.

Citation Format: Thomas Farge{Authors}. Studying cytarabine resistance through PDX models in acute myeloid leukemia. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B06.
Abstract B22: Establishment of Patient-Derived Xenograft (PDX) Models of Ovarian Cancer
Authors: Liang Li , Mercado-Uribe Imelda , Niu Na , Jiang Yi , Cheng Wenjun , Broaddus Russell , Bast Robert , Mills Gordon , Sood Anil K. , Liu Jinsong
Published: March 2017

Ovarian cancer is the most lethal gynecological malignancy. The majority of ovarian cancer patients are diagnosed at an advanced stage of disease, and the lack of good early screening and diagnostic tests is one of the reasons for the low overall survival rate. Moreover, there is no good marker to predict patients' response to chemotherapy. Patient-derived xenografts (PDXs) have become the most promising preclinical model for gynecologic malignances. We have successfully established 22 PDX models derived from ovarian cancer patients' surgical specimens implanted into severe combined immunodeficient (SCID) mice, non-obese diabetic (NOD)-SCID or Nude mice. The majority of the PDX models were generated from patients' samples diagnosed with high-grade serous carcinoma including 3 with BRCA1/2 mutations, as well as less common types of ovarian cancers such as low-grade serous, endometrioid, mucinous carcinomas, and carcinosarcoma. PDXs have been established from solid masses as well as from ascites. We have optimized protocol for establishing ovarian PDXs including implantation and collection methods, tumor type (solid versus ascites), and type of mouse strains used. Using SCID mice, our success rate exceeded 80% and recent data indicated that the success rate in NOD/SCID mice was higher. The link between the pathology and PDX core, the “triage protocol” and ongoing PARP inhibitor trials will provide an important array of PDXs including pre- and post-treatment PDXs for exploration for biomarkers as well as for co-clinical trials to validate the utility of rational drug combinations. All models were validated using short tandem repeats (STR) and compared to the H&E and immunohistochemistry stains from the matching patient's tissue. We also examined the expression of B7-H4, a novel member of the B7 family immune checkpoint regulators, in 9 patient-derived xenografts (PDXs) of high-grade ovarian serous carcinoma. Our data showed that B7-H4 proteins were expressed in 8 of 9 PDX models of high-grade serous carcinoma, suggesting that PDXs may be useful for studying immunotherapy.

Citation Format: Li Liang, Imelda Mercado-Uribe, Na Niu, Yi Jiang, Wenjun Cheng, Russell Broaddus, Robert Bast, Gordon Mills, Anil K. Sood, Jinsong Liu. Establishment of Patient-Derived Xenograft (PDX) Models of Ovarian Cancer. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B22.
Abstract B23: Neuroblastoma patient-derived orthotopic xenografts: Clinically relevant models for drug testing
Authors: Bexell Daniel , Braekeveldt Noémie , Mohlin Sofie , Wigerup Caroline , Gisselsson David , Tadeo Irene , Berbegall Ana P. , Navarro Sam , Noguera Rosa , Påhlman Sven
Published: March 2017

Background: We previously established neuroblastoma patient-derived orthotopic xenografts (PDXs) by implanting patient neuroblastoma fragments into immunodeficient NSG mice. SNP array analysis confirmed that PDXs maintain patient-specific chromosomal aberrations 1p del, MYCN amp and 17q gain. Immunohistochemistry showed that PDXs retain neuroblastoma markers and a highly infiltrative growth pattern. Importantly, we found spontaneous distant metastasis to lungs, liver and bone marrow. In vitro cultures established from the PDXs express neuroblastoma markers and retain their tumorigenic and metastatic ability in vivo after orthotopic injection.

Methods and Results: Given the important role of the tumor stroma for tumor progression and treatment response, we examined PDX stroma by immunohistochemistry. PDXs were highly vascularized with mouse endothelial cells and two PDX models also formed tumor vasculature by co-engrafted human tumor endothelial cells. Tumors contained pericytes, cancer-associated fibroblasts, macrophages and extracellular components resembling the patient disease. PDXs established in athymic nude mice additionally developed intratumoral lymphatic vessels and contained mouse-derived CD45+ lymphoid cells. Thus, PDXs reflect important tumor microenvironment hallmarks for high-stage neuroblastoma. Furthermore, we demonstrate the feasibility of using short-term in vitro cultured PDX-derived cells as a drug-testing model, and show that the HIF2A oncogene is transcriptionally regulated at hypoxia via the PI3K/mTORC2 pathway in these cells. The results establish the PI3K and mTORC2 pathways as potential therapeutic targets of aggressive neuroblastoma.

Conclusion: Neuroblastoma orthotopic PDXs reflect clinical aspects of high-risk disease including spontaneous metastasis, copy number changes and microenvironmental hallmarks. Neuroblastoma PDXs are relevant models for in vitro and in vivo preclinical drug testing.

Citation Format: Daniel Bexell, Noémie Braekeveldt, Sofie Mohlin, Caroline Wigerup, David Gisselsson, Irene Tadeo, Ana P. Berbegall, Sam Navarro, Rosa Noguera, Sven Påhlman. Neuroblastoma patient-derived orthotopic xenografts: Clinically relevant models for drug testing. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B23.
Abstract B29: Effects of prenatal exposure to cancer treatment: The development of a placental murine xenograft model
Authors: Verheecke Magali , Devlies Wout , Hermans Els , Amant Frédéric
Published: March 2017

The aim of this study was to develop a suitable murine xenograft model to examine the possible effect of drugs or chemotherapeutic agents on the placental tissue.

Methods: The test population consisted of 4 examination groups of six immunodefficient nude mice. After the mice were ovariectomised and hormonal stimulated (17b estradiol and progesterone pellets), placental tissue derived from first and third trimester pregnancies was engrafted subcutaneously bilateral in the interscapular fat pad. hCG (human chorionic gonadotrophin) secretion was measured in serum and urine by an enzyme-linked immunosorbent assay (ELISA). To examine the viability and preservation of the placental tissue, factors for proliferation (hCG, Ki67), apoptosis (cleaved caspase-3) and murine angiogenesis (CD31) were evaluated by immunohistochemistry (IHC). The expression level of genes relevant for the angiogenesis (IGF-1, PGF, IGF-2), inflammation (eNOS) and proliferation (Flk-1, Flt-1) was compared by using reverse transcription- quantitative real-time polymerase chain reaction (RT-qPCR).

Results: Comparing the placental tissue before and after engraftment, we found preserved structure and histological features. Also, the PCR analysis showed preserved genetic characteristics of the primary engrafted placental tissue. hCG secretion, evaluated by ELISA in the urine and blood, was present for 3 weeks.

Conclusion: We created a murine xenograft model with proven stability and preserved structure of the engrafted placental tissue for 3 weeks. This established murine xenograft model will be useful to examine the effect of cancer treatment; moreover, it could serve as a model for other fetal toxicity studies.

Citation Format: Magali Verheecke, Wout Devlies, Els Hermans, Frédéric Amant. Effects of prenatal exposure to cancer treatment: The development of a placental murine xenograft model. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B29.
Abstract B44: When murine tumors are thought to be human: A drawback of patient derived xenografts.
Authors: Menéndez Camino , Salvador Beatriz , Muñoz Manuel , Baños Natalia , Sarno Francesca , López-Casas Pedro P , Hidalgo Manuel
Published: March 2017

The use of preclinical models is essential in every aspect of translational cancer research, from the biologic understanding of the disease to the development of new treatments. Patient Derived Xenograft (PDX) models are increasingly used in translational cancer research due to their advantages over other preclinical models. However, although it has been widely demonstrate that these kind of models are predictive of clinical outcome, there are also some drawbacks when working with them.

Analyzing our PDX model collection, we have observed that there is a small percentage of cases in which a murine tumor is developed instead of the original human one by a process that has been called horizontal oncogenesis. This process was already observed and described in the early 80´s, however, it is still not well understood and the molecular mechanisms by which it happens remain unknown.

In order to determine the origin of the different murine tumors observed in our mice, we performed immunohistochemistry characterization of our altered models and found two different types of murine tumors: murine fibrosarcomas, which were observed in Colorectal and Pancreatic Ductal Adenocarcinoma PDX models; and murine lymphomas, that were observed mainly in Lung PDX models when they were implanted in Nod-scid mice. We also found a case in which a human lymphoproliferation grew in the animals instead of the sample from the small cell lung cancer obtained from the patient.

As these murine tumors grow in the same place where the human donor tumor was implanted, it is important to have a quick and effective method to identify them before performing any study with these altered models. In this regard, we have implemented a simple technique based on PCR analysis with primers that recognize K-Ras. We have designed an estrategy in which we can obtain amplicons of different sizes depending on their human or murine origin.

Although we still have to analize some of our PDX models, using this methodology we have confirmed that murine tumors appear in a very low percentage of cases (less than 5% to date). However, even with this low incidence we consider that is essential to identify those murine tumors as soon as possible in order to avoid wasting time, money and resources.

Citation Format: Camino Menéndez, Beatriz Salvador, Manuel Muñoz, Natalia Baños, Francesca Sarno, Pedro P López-Casas, Manuel Hidalgo. When murine tumors are thought to be human: A drawback of patient derived xenografts.. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B44.
Abstract IA02: Introduction to the EuroPDX Consortium
Authors: Roman-Roman Sergio
Published: March 2017

Started in early 2013, EurOPDX gathers 16 academic institutions throughout Europe including 6 Comprehensive Cancer Centres. Each institution is part of a hospital or is collaborating with a neighboring one. EurOPDX includes world-renowned experts at the forefront of research in basic, preclinical, translational and clinical oncology across multiple pathologies, and displays a wide range of expertise in technological platforms. The virtual PDX collection of the consortium consists of more than 1,500 subcutaneous and orthotopic models for more of 30 different pathologies. Our objective is to improve the predictability of preclinical data by (i) improving characterization of the models, (ii) implementing new PDX models to strengthen the representativeness of the collection, and humanized PDX models, (iii) harmonizing working practice, (iv) Integrating complementary models (e.g. ex vivo 2D and 3D assays) in innovative drug development pipelines, and (v) leveraging deep molecular and pharmacogenomic profiling data of the collection of models to discover predictive biomarkers, new targets, and new strategies to overcome drug resistance. In this lecture I will illustrate the value of the consortium with a few examples of collaborative projects involving academic labs but also industrial partners. In particular, I will discuss the current strategies to setting-up the logistics for the performance of multicenter (and sometimes multipathologies) preclinical and co-clinical trials in a collection of fully characterized PDX models.

Citation Format: Sergio Roman-Roman. Introduction to the EuroPDX Consortium. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA02.
Abstract IA04: Lgr5 stem cell-based organoids in human disease
Authors: Clevers Hans
Published: March 2017

The intestinal epithelium is the most rapidly self-renewing tissue in adult mammals. We originally defined Lgr5 as a Wnt target gene, transcribed in colon cancer cells. Two knock-in alleles revealed exclusive expression of Lgr5 in cycling, columnar cells at the crypt base. Using lineage tracing experiments in adult mice, we found that these Lgr5+ve crypt base columnar cells (CBC) generated all epithelial lineages throughout life, implying that they represent the stem cell of the small intestine and colon. Lgr5 was subsequently found to represent an exquisitely specific and almost ‘generic’ marker for stem cells, including in hair follicles, kidney, liver, mammary gland, inner ear tongue and stomach epithelium.

Single sorted Lgr5+ve stem cells can initiate ever-expanding crypt-villus organoids, or so called ‘mini-guts’ in 3D culture. The technology is based on the observation that Lgr5 is the receptor for a potent stem cell growth factor, R-spondin. Similar 3D cultures systems have been developed for the Lgr5+ve stem cells of human stomach, liver, pancreas, prostate and kidney. Using CRISPR/Cas9 technology, genes can be efficiently modified in organoids of various origins.

Citation Format: Hans Clevers. Lgr5 stem cell-based organoids in human disease. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA04.
Abstract IA05: PDX in colorectal cancer and carcinoma of the anal canal
Authors: Dangles-Marie Virginie
Published: March 2017

Through 2 examples of digestive tumors, (colorectal cancer, “CRC”, and anal squamous cell carcinoma, “ASCC”), we will present the development and use of patient-derived tumor xenografts.

Colorectal cancer remains a major cause of mortality worldwide and CRC patient death is generally attributable to metastasis development. By contrast, ASCC is a rare tumor (< 5% of all lower gastrointestinal tract malignancies in Europe) but with increasing incidence and mutilating surgery for patients with chemoradiotherapy-resistant tumors. Consequently, these both digestive tumors require new therapeutic approaches and relevant preclinical models to identify and test new drugs/combinations. In this context, we develop and characterize patient-derived CRC and ASCC xenografts.

We will illustrate the capacity of these PDXs to recapitulate the intratumoral clonal heterogeneity, gene expression profile, key molecular alterations, histology and drug response of the patient tumors through passages in mice. In addition to these now well-known features depicted in a large number of tumor types, we will discuss about practical situations (orthotopic engraftment, impact of mouse host, criteria for measuring drug efficacy). Finally, we will report alternative methods as ex vivo tumor spheres we have developed.

Citation Format: Virginie Dangles-Marie. PDX in colorectal cancer and carcinoma of the anal canal. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA05.
Abstract IA09: Expression profiling of colorectal cancer PDX models for disease stratification and tumor-stroma interaction analysis
Authors: Medico Enzo
Published: March 2017

Tumor-stroma interactions have long been implicated in neoplastic aggressiveness and resistance to treatment. In PDX models, after engraftment, the stromal components are contributed by the mouse host. As a consequence, transcripts expressed by cancer cells can be distinguished from stromal transcripts by their species of origin. We therefore exploited species-specific expression profiling of colorectal cancer (CRC) PDXs to evaluate the involvement of stromal components in recently defined CRC transcriptional subtypes. We found that stroma-derived transcripts profoundly affect the overall tumor transcriptome, and that a previously defined poor prognosis subtype is actually endowed with abundant stroma. To stratify CRC based on cancer cell-intrinsic transcriptional features, we performed class discovery on a human-specific gene expression dataset of 515 CRC PDXs, and identified five CRC intrinsic subtypes (CRIS). CRIS classification successfully categorized independent sets of primary and metastatic CRC tumors, with limited overlap on existing transcriptional classes and unprecedented predictive and prognostic performances. In a complementary approach, we focused on stroma-specific transcripts to define expression signatures reflecting the abundance in human CRC samples of fibroblasts, leukocytes and endothelial cells. Stromal scores were found to correlate with poor CRC prognosis and resistance of rectal cancer to preoperative radiotherapy, highlighting the microenvironment as a variable and dynamic component of CRC, with diagnostic and therapeutic potential.

Citation Format: Enzo Medico. Expression profiling of colorectal cancer PDX models for disease stratification and tumor-stroma interaction analysis. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA09.
Abstract A10: A distinct gene module for T cell dysfunction uncoupled from T cell activation and controlled by metallothioneins
Authors: Singer Meromit , Wang Chao , Cong Le , Marjanovic Nemanja D. , Kowalczyk Monika S. , Zhang Huiyuan , Nyman Jackson , Sakuishi Kaori , Kurtulus Sema , Gennert David , Xia Junrong , Kwon John YH , Nevin James , Herbst Rebecca H. , Yanai Itai , Rozenblatt-Rosen Orit , Kuchroo Vijay K. , Regev Aviv , Anderson Ana C.
Published: March 2017

Reversing the dysfunctional (also known as “exhausted”) T cell state that arises in cancer and chronic viral infections is the focus of therapeutic interventions; however, current therapies are effective in only some patients and for only some tumor types. To gain a deeper molecular understanding of the dysfunctional T cell state, we leveraged mouse models to analyze RNA profiles of CD8+ tumor-infiltrating lymphocytes (TILs) at various functional states. In a comparative study we identified metallothioneins, regulators of zinc metabolism, as drivers of T cell dysfunction and used genetic perturbation to identify, for the first time, a distinct gene module for T cell dysfunction that is uncoupled from T cell activation and associated with a CD8+ Treg signature. An analysis of TILs at single-cell resolution revealed that our dysfunction module negatively correlates with activation signatures also at the single-cell level, indicating that our uncoupled signatures for T cell dysfunction and activation can represent cell-intrinsic states. Clustering of the single-cells revealed a previously uncharacterized subpopulation of CD8+ TILs that was strongly enriched for our novel dysfunction signature, but not for activation signatures. This subpopulation was depleted of cells from a metallothionein KO mouse model in which T cell dysfunction was not observed, implying that we have indeed identified a phenotypically dysfunctional subpopulation. Using CRISPR/Cas9 genome editing we validate that Gata-3, a transcription factor expressed specifically in our identified subpopulation, is a driver of the dysfunctional phenotype in CD8+ TILs. Our results open novel avenues for specifically targeting the dysfunctional T cell state while leaving T cell activation programs intact.

Citation Format: Meromit Singer, Chao Wang, Le Cong, Nemanja D. Marjanovic, Monika S. Kowalczyk, Huiyuan Zhang, Jackson Nyman, Kaori Sakuishi, Sema Kurtulus, David Gennert, Junrong Xia, John YH Kwon, James Nevin, Rebecca H. Herbst, Itai Yanai, Orit Rozenblatt-Rosen, Vijay K. Kuchroo, Aviv Regev, Ana C. Anderson. A distinct gene module for T cell dysfunction uncoupled from T cell activation and controlled by metallothioneins. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A10.
Abstract A61: Human BDCA3high dendritic cells infiltrate breast and ovarian tumors but are functionally altered
Authors: Hubert Margaux , Doffin Anne-Claire , Verronese Estelle , Durand Isabelle , Caux Christophe , Valladeau-Guilemond Jenny
Published: March 2017

Dendritic cells (DC) are key cellular players in the induction of antigen-specific anti-tumoral immunity. BDCA3high DC are equivalent to mouse CD8α+ DC and specialized for Ag cross-presentation. Interestingly, they are also the main producers of interferon-λ (IFN-λ), a recently discovered cytokine family with antiviral, anti-proliferative and anti-tumoral properties. In this study, we first demonstrated by multiparametric flow cytometry that human BDCA3high DC are present in breast and ovarian tumors. Secondly, we observed that their IFN-λ synthesis upon TLR3 activation is reduced compared to their blood equivalents. Using in vitro BDCA3high DC generated from CD34+ hematopoietic stem cells, we are currently deciphering mechanisms of this alteration. This study shows for the first time the infiltration of solid tumors by this rare DC subset and highlights a functional DC alteration which has to be taken into account in the design of new anti-tumoral immunotherapeutic strategies.

Grants: Ligue contre le cancer, ANRS, INCA (PL BIO2011-155)

Citation Format: Margaux Hubert, Anne-Claire Doffin, Estelle Verronese, Isabelle Durand, Christophe Caux, Jenny Valladeau-Guilemond. Human BDCA3high dendritic cells infiltrate breast and ovarian tumors but are functionally altered. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A61.
Abstract A66: Molecular profiling of regulatory T cells in a genetic mouse model of lung adenocarcinoma
Authors: Li Amy , Bhutkar Arjun , Joshi Nikhil S. , Jacks Tyler E.
Published: March 2017

The clinical success of immune checkpoint blockade in the treatment of various cancer types provides proof-of-principle that targeting immunosuppression in the tumor microenvironment is an effective therapeutic strategy. Regulatory T cells (Tregs) are a CD4+ T lymphocyte population that may play a dominant role in impairing anti-tumor immune responses. Characterized by their expression of the transcriptional regulator FOXP3, Tregs can inhibit adaptive immune responses through the production of inhibitory cytokines, direct cell killing, competition with other T cell subsets for antigen or other substrates, and suppression of antigen presentation. To recapitulate the strong immunosuppression observed in endogenous tumors, we have used an autochthonous, inducible mouse model of lung adenocarcinoma previously generated in the Jacks lab that is driven by expression of oncogenic KrasG12D and loss of p53 (KP model). Indeed, tumor development in the KP model is accompanied by an expansion of lung-resident Tregs, and previous work in the lab has shown that this population actively restrains anti-tumor T cell responses. In this study, we have transcriptionally profiled lung Tregs in the KP model to identify pathways to preferentially target Tregs in tumor-bearing lungs. We have shown that lung Tregs have a distinct transcriptional phenotype that shares characteristics with that of previously described “effector” Treg populations in a variety of tissue and inflammatory contexts. Furthermore, the KP lung Treg gene signature is associated with survival when applied to the bulk transcriptomes of various tumor types, and is better correlated with patient outcome in lung adenocarcinoma than a number of immune parameters, including mutation burden and expression of CD8A, FOXP3, and GZMA. Together, our data demonstrate that a gene expression signature drawn from cancer-associated Tregs with a distinct, functional phenotype may be useful as a biomarker for clinical outcomes in multiple tumor types.

Citation Format: Amy Li, Arjun Bhutkar, Nikhil S. Joshi, Tyler E. Jacks. Molecular profiling of regulatory T cells in a genetic mouse model of lung adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A66.
Abstract A70: Tumor growth enhancement under obese conditions: Role of intratumoral myeloid cells
Authors: al-Ramadi Basel K. , Kaimala Suneesh , Mohamed Yassir A. , Al-Sbiei Ashraf , Bashir Ghada , Fernandez-Cabezudo Maria J.
Published: March 2017

Obesity is a metabolic disorder characterized by a state of chronic inflammation. Based on epidemiological evidence, obesity has been linked to increased risk of developing several types of cancer. However, the mechanisms underlying this phenomenon remain unknown. Successful growth of cancer cells hinges on developing mechanisms to evade host immunosurveillance, particularly within the tumor microenvironment. In the current study, we utilized a high-fat-diet (HFD)-induced obesity mouse model to gain mechanistic insight into the effect of obesity on progression of implantable syngeneic tumors. When lean or obese mice were implanted with B16.F1 melanoma or MC38 colon carcinoma, tumor growth was more robust in obese group than lean controls, suggesting that obese conditions promote tumor growth. Multi-color flow cytometric analysis and gene expression profiling were carried out on distinct subpopulations of intratumoral myeloid cells. Tumors of lean mice had higher percentages of myeloid cells compared to obese counterparts with characteristics typical of activated inflammatory macrophages. In contrast, tumors of obese mice had disproportionately higher frequency of myeloid derived suppressor cells (MDSC) with a gene signature suggestive of immunosuppressive potential. These findings highlight the role of metaflammation in tumor growth promotion via the regulation of frequency and activation status of distinct subpopulations of intratumoral myeloid cells.

Citation Format: Basel K. al-Ramadi, Suneesh Kaimala, Yassir A. Mohamed, Ashraf Al-Sbiei, Ghada Bashir, Maria J. Fernandez-Cabezudo. Tumor growth enhancement under obese conditions: Role of intratumoral myeloid cells. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A70.
Abstract A75: Designed Ankyrin Repeat Proteins (DARPins) as recognition motifs in chimeric antigen receptors
Authors: Balakrishnan Ashwini , Salter Alexander I. , Plückthun Andreas , Riddell Stanley R.
Published: March 2017

Chimeric antigen receptors (CARs) consist primarily of single chain variable fragments (scFv) linked to the T cell activation (CD3ζ) and costimulatory domains. We investigated whether alternative recognition motifs selected for ligand binding from synthetic libraries of Designed Ankyrin Repeat proteins (DARPins) could be incorporated into CARs. As proof of principle, we linked a DARPin (DARPin E01) specific for EGFR to the CAR signaling domain and compared anti-tumor function with a high affinity CAR containing the Cetuximab scfv, which recognizes an overlapping epitope. Our in vitro results show that DARPin CARs designed with flexible linkers and with short and long spacer domains exhibit specific cytotoxicity, cytokine secretion and proliferation against EGFR+ targets that is comparable to the Cetuximab CAR. We tested DARPins CARs in an in vivo breast cancer tumor model with EGFR+ MDA-MB-231 tumor cells and found enhanced anti-tumor clearance with both E01 DARPin and Cetuximab scFV CARs. We show that an EpCAM-specific DARPin chimeric costimulatatory receptor (CCR) can also be used in conjunction with a scFV CAR targeting ROR1 to provide combinatorial antigen recognition and enhance T cell function against tumor cells expressing both targets. The EpCAM-specific DARPin CCR combined with first or second generation ROR1 scFv CARs enhanced T cell cytokine secretion and proliferation. The compact stable structure of DARPins should facilitate linking of multiple DARPins targeting different antigens reducing the likelihood of antigen loss. In summary, the stable structural scaffold of DARPins and the presence of diverse binder libraries make them attractive recognition motifs to incorporate into CARs.

Citation Format: Ashwini Balakrishnan, Alexander I. Salter, Andreas Plückthun, Stanley R. Riddell. Designed Ankyrin Repeat Proteins (DARPins) as recognition motifs in chimeric antigen receptors. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A75.