Dynamic Regulation of Expression of KRAS and Its Effectors Determines the Ability to Initiate Tumorigenesis in Pancreatic Acinar Cells

Pancreatic acinar cells are a cell type of origin for pancreatic cancer that become progressively less sensitive to tumorigenesis induced by oncogenic Kras mutations after birth. This sensitivity is increased when Kras mutations are combined with pancreatitis. Molecular mechanisms underlying these observations are still largely unknown. To identify these mechanisms, we generated the first CRISPR-edited mouse models that enable detection of wild-type and mutant KRAS proteins in vivo. Analysis of these mouse models revealed that more than 75% of adult acinar cells are devoid of detectable KRAS protein. In the 25% of acinar cells expressing KRAS protein, transcriptomic analysis highlighted a slight upregulation of the RAS and MAPK pathways. However, at the protein level, only marginal pancreatic expression of essential KRAS effectors, including C-RAF, was observed. The expression of KRAS and its effectors gradually decreased after birth. The low sensitivity of adult acinar cells to Kras mutations resulted from low expression of KRAS and its effectors and the subsequent lack of activation of RAS/MAPK pathways. Pancreatitis triggered expression of KRAS and its effectors as well as subsequent activation of downstream signaling; this induction required the activity of EGFR. Finally, expression of C-RAF in adult pancreas was required for pancreatic tumorigenesis. In conclusion, our study reveals that control of the expression of KRAS and its effectors regulates the sensitivity of acinar cells to transformation by oncogenic Kras mutations. SIGNIFICANCE: This study generates new mouse models to study regulation of KRAS during pancreatic tumorigenesis and highlights a novel mechanism through which pancreatitis sensitizes acinar cells to Kras mutations.

Pancreatic Ductal Deletion of Hnf1b Disrupts Exocrine Homeostasis, Leads to Pancreatitis, and Facilitates Tumorigenesis

BACKGROUND & AIMS

The exocrine pancreas consists of acinar cells that produce digestive enzymes transported to the intestine through a branched ductal epithelium. Chronic pancreatitis is characterized by progressive inflammation, fibrosis, and loss of acinar tissue. These changes of the exocrine tissue are risk factors for pancreatic cancer. The cause of chronic pancreatitis cannot be identified in one quarter of patients. Here, we investigated how duct dysfunction could contribute to pancreatitis development.

METHODS

The transcription factor Hnf1b, first expressed in pancreatic progenitors, is strictly restricted to ductal cells from late embryogenesis. We previously showed that Hnf1b is crucial for pancreas morphogenesis but its postnatal role still remains unelucidated. To investigate the role of pancreatic ducts in exocrine homeostasis, we inactivated the Hnf1b gene in vivo in mouse ductal cells.

RESULTS

We uncovered that postnatal Hnf1b inactivation in pancreatic ducts leads to chronic pancreatitis in adults. Hnf1bΔ^duct mutants show dilatation of ducts, loss of acinar cells, acinar-to-ductal metaplasia, and lipomatosis. We deciphered the early events involved, with down-regulation of cystic disease-associated genes, loss of primary cilia, up-regulation of signaling pathways, especially the Yap pathway, which is involved in acinar-to-ductal metaplasia. Remarkably, Hnf1bΔ^duct mutants developed pancreatic intraepithelial neoplasia and promote pancreatic intraepithelial neoplasia progression in concert with KRAS. We further showed that adult Hnf1b inactivation in pancreatic ducts is associated with impaired regeneration after injury, with persistent metaplasia and initiation of neoplasia.

CONCLUSIONS

Loss of Hnf1b in ductal cells leads to chronic pancreatitis and neoplasia. This study shows that Hnf1b deficiency may contribute to diseases of the exocrine pancreas and gains further insight into the etiology of pancreatitis and tumorigenesis.

Complete Regression of Advanced Pancreatic Ductal Adenocarcinomas upon Combined Inhibition of EGFR and C-RAF

Five-year survival for pancreatic ductal adenocarcinoma (PDAC) patients remains below 7% due to the lack of effective treatments. Here, we report that combined ablation of EGFR and c-RAF expression results in complete regression of a significant percentage of PDAC tumors driven by Kras/Trp53 mutations in genetically engineered mice. Moreover, systemic elimination of these targets induces toxicities that are well tolerated. Response to this targeted therapy correlates with transcriptional profiles that resemble those observed in human PDACs. Finally, inhibition of EGFR and c-RAF expression effectively blocked tumor progression in nine independent patient-derived xenografts carrying KRAS and TP53 mutations. These results open the door to the development of targeted therapies for PDAC patients.

A Randomized Controlled Trial of Opt-in Versus Opt-Out Colorectal Cancer Screening Outreach

OBJECTIVES

METHODS:: RESULTS:: Patients randomized to opt-in agreed to participate 23.1% of the time, and only 2.5% of those in opt-out chose not to participate. FIT kits were mailed to 22.4% and 93% of patients in opt-in and opt-out arms, respectively. In intention-to-screen analysis, patients in the opt-out arm had a higher FIT completion rate (29.1%) than in the opt-in arm (9.6%) (absolute difference 19.5%; 95% confidence interval, 10.9-27.9%; P < .001). Results were similar in subgroup analysis of those sent initial messaging through the EHR portal (9.5% opt-in versus 37.5% in opt-out).

CONCLUSIONS

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Effect of length of time post-mortem on quality and freezing capacity of Cantabric chamois (Rupicapra pyrenaica parva) epididymal spermatozoa

Genome Resource Banks are keystones in the ex-situ conservation of wild species. Post-mortem (PM) collection of epididymal spermatozoa is an opportunistic and valuable source of germplasm, the time from the death of the animal limits its use. Seeking to improve germplasm preservation strategies for the chamois (Rupicapra sp.), the effect of PM time on epididymal sperm quality and freezability was studied using the Cantabrian chamois. Samples were classified according to PM collection time, up to 216 h (refrigerated), and cryopreserved (Tris-citric acid-fructose, 430 mOsm/kg, 15% egg yolk, 8% glycerol; freezing at -20 °C/min). Sperm quality was assessed after recovery and post-thawing (motility by CASA, HOS test, abnormal forms, cytoplasmic droplets, and viability and acrosomal damage by flow cytometry). The sperm mass pH and osmolality showed a positive correlation with time. Total sperm motility dropped after 2 days PM, with progressivity and sperm velocities remained similar up to 3 days PM. Sperm freezability was acceptable, with the post-thawing HOST, motility, progressivity, VAP, VCL, VSL and BCF negatively correlating with PM time. Overall, chamois epidydimal samples were not adequate for preservation after 6 days PM. Freezability capacity could make these spermatozoa suitable for specific ART even if kept refrigerated for several days PM.

Traduction sémantique en français et implémentation du Nursing Activities Score en Belgique

Introduction : L’évaluation du temps de travail en soins infirmiers est une pratique courante aux soins intensifs. Elle permet de calculer un ratio infirmière/patient optimal qui est un enjeu majeur pour assurer la qualité des soins et maîtriser les coûts des soins de santé. Le Nursing Activities Score (NAS) permet de calculer ce ratio, mais l’outil n’a jamais été traduit en français et adapté à la Belgique.

Objectif : Traduire et adapter le NAS à la Belgique francophone.

Méthodes: L’échelle a été traduite par deux traducteurs indépendants de l’anglais vers le français. Ensuite, une traduction rétrograde du français à l’anglais a été réalisée. Une adaptation culturelle a été effectuée en réunissant un groupe de 13 infirmiers belges. Enfin, l’échelle traduite a été validée et implémentée dans deux unités de soins intensifs (USI) distinctes en Belgique francophone.

Résultats : La traduction rétrograde était similaire à la première traduction. La réunion avec le groupe d’experts a permis de trouver un consensus sur l’adaptation de l’échelle et le tutoriel adaptés au contexte des soins en Belgique. Pour la validation, le NAS a été encodé chez 113 patients et avec 981 NAS encodés dans deux USI, la médiane de NAS/patient était respectivement de 69 et 76 %. Le temps médian d’encodage du NAS était de trois minutes par patient. Nous avons observé une compliance élevée de l’encodage du NAS (respectivement 99 et 76 %).

Conclusions : Nous avons validé une échelle traduite en français conforme à la version originale et adaptée au contexte des soins en Belgique.

Genetically Engineered Mouse Models of K-Ras-Driven Lung and Pancreatic Tumors: Validation of Therapeutic Targets

K-RAS signaling has been intensely studied for over 40 years. Yet, as of today, no drugs have been approved to treat K-RAS mutant cancers. Since the turn of the century, scientists have used genetically engineered mouse (GEM) models to reproduce K-RAS mutant cancers in a laboratory setting to elucidate those molecular events responsible for the onset and progression of these tumors and to identify suitable therapies. In this review, we outline a brief description of available GEM models for two tumor types known to be driven by K-RAS mutations: lung adenocarcinoma and pancreatic ductal adenocarcinoma. In addition, we summarize a series of studies that have used these GEM tumor models to validate, either by genetic or pharmacological approaches, the therapeutic potential of a variety of targets, with the ultimate goal of translating these results to the clinical setting.

Abstract P4-10-05: Engaging linguistically and ethnically diverse low income women in health research: A randomized controlled trial

Background: Underserved breast cancer survivors are typically offered fewer opportunities to participate in cancer research. To address this disparity, a community based navigator program, Shanti's Margot Murphy Breast Cancer Program (Shanti) initiated a collaboration with UCSF researchers and BreastCancerTrials.org (BCT), a nonprofit clinical trials matching service to explore the potential role of a trusted community-based organization as a source of culturally appropriate education and access to clinical trial information. Through formative research, we developed the Health Research Engagement Intervention (HREI), a one-on-one navigator-client education session emphasizing the range of treatment and non-treatment quality-of-life and observational studies, conducted at a time when the participant is not in the initial crisis of diagnosis. The HREI ends by providing participants with an information card listing BCT and other organizations that provide information about health research for breast cancer patients and survivors.

Methods: We tested the HREI in a randomized controlled trial, comparing the HREI to simply providing the information card. Pre and post intervention surveys one month apart measured our primary outcome of health research information-seeking behavior. Secondary outcomes include health research knowledge, attitudes towards research participation, and health empowerment. All Shanti clients who spoke English, Cantonese or Spanish and had “low care navigation needs” (either completed treatment or no longer in the crisis of initial diagnosis and/or burdened by treatment protocols) were eligible.

Results: We recruited 133 Shanti Clients, including 59 who spoke English, 48 Cantonese, and 26 Spanish; 66 were randomized to the intervention arm and 67 to the control arm, and 130 completed both pre- and post-test surveys. Almost one-third of participants in both the intervention and control arms reported having talked to someone about health research or having called a telephone number or visited a website listed on the card (30% vs. 30%, p=0.94); a smaller proportion of participants confirmed that their information-seeking was related to the content of the educational materials (17% vs. 9%, p=0.22). On average the change from pre- to post-test in a 5-item knowledge score, adjusted for pre-test knowledge, was greater in the intervention group than in the control group (p=0.028), but the proportion of participants who were very confident that they could find health research information (had health empowerment) remained essentially unchanged in both study arms (intervention: 20% post vs. 21% pre, p=0.76; control: 25% post vs. 25% pre, p=1.00). Women were more likely to seek information if they had higher pre-test knowledge scores (odds ratio [OR]=3.5 per item, 95% confidence interval [CI] 1.5-8.4) or a greater increase in knowledge from pre- to post-test (OR=2.2 per item, 95% CI 1.1-4.7); there was no association between information-seeking and health empowerment (OR=0.6, 95% CI 0.2-2.5) or study arm (OR=1.6, 95% CI 0.5-4.9).

Conclusion: The HREI had a positive impact on knowledge of health research but did not significantly affect health empowerment or health research information-seeking behavior.

Citation Format: Joseph G, Nickell A, Cohen E, Burke NJ, Colen S, Lawlor K, Guerra C, Stewart SL. Engaging linguistically and ethnically diverse low income women in health research: A randomized controlled trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-10-05.

Abstract P6-12-19: Healing art: Breast cancer survivor experiences with nipple-areola tattoo procedures during breast reconstruction

Background: Nipple-areola tattoos can provide restoration of a natural looking breast that more closely resembles its pre-surgical appearance while avoiding additional surgeries. To date, the majority of nipple-areola tattoo procedures are performed by healthcare providers with minimal training in tattoo procedures. Substandard results explain the high rates of dissatisfaction among women who receive nipple-areola tattoos. In response, professional tattoo artists have emerged as an alternative provider for women seeking reconstruction. However, few studies have examined expectations and experiences of women undergoing nipple-areola tattoo procedures provided by a professional tattoo artist outside of the traditional healthcare setting. Methods: In-depth interviews were conducted with a racially/ethnically diverse group of 30 women who had undergone nipple-areola tattooing in the past 0-2 years. Interviews were conducted in English, Spanish, Chinese, and Arabic, recorded, and translated and transcribed into English for analysis. A team of three researchers conducted iterative reviews of the data which included closely reading each transcript, coding, running queries of codes, and developing summary documents to highlight recurrent concepts and patterns which were shared and discussed in group meetings. Results: Interview narratives addressed the often unexpected impact nipple-areola tattooing had on body image, self-esteem, emotional well-being, and interpersonal relationships. Women described their decision-making processes as weighing concern about the needle, the pain, and uncertainty about the tattoo artist, setting for the procedure, and outcome with the opportunity to return to a more “normal” appearance without further surgeries. Women discussed how their initial preconceptions of tattoos and tattoo parlors were ameliorated by the spa-like setting and the tattoo artist's anticipation of such concerns which enhanced her ability to put them at ease and provide professional and compassionate care. Participants noted the integral role the tattoo artist played in their positive experiences, describing her as both an “artist” and “caregiver.” The manner in which she guided them through the decision-making process regarding the color, size, shape, and placement of their nipple-areola tattoo was noted as particularly significant and empowering. Conclusions: Nipple-areola tattooing is an acceptable and meaningful reconstruction process for medically underserved public hospital patients. Our results indicate that women should be informed of nipple-areola tattooing as an alternative to more invasive, surgical reconstruction options. Results also illustrate how the healthcare system can extend beyond the traditional healthcare setting to include and leverage non-clinical and non-traditional specialists to provide appropriate care and positive breast health outcomes for women. In order to increase access and legitimacy to these services, additional research is needed to understand how to bring tattoo artists “in-house” (i.e., into the medical setting) and how to incorporate tattoo artists into breast health teams.

Citation Format: Napoles TM, Guerra C, Orenstein F, Luce JA, Merritt S, Burke NJ. Healing art: Breast cancer survivor experiences with nipple-areola tattoo procedures during breast reconstruction [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-12-19.

Chronic pancreatitis and lipomatosis are associated with defective function of ciliary genes in pancreatic ductal cells

Genetic diseases associated with defects in primary cilia are classified as ciliopathies. Pancreatic lesions and ductal cysts are found in patients with ciliopathic polycystic kidney diseases suggesting a close connection between pancreatic defects and primary cilia. Here we investigate the role of two genes whose deletion is known to cause primary cilium defects, namely Hnf6 and Lkb1, in pancreatic ductal homeostasis. We find that mice with postnatal duct-specific deletion of Hnf6 or Lkb1 show duct dilations. Cells lining dilated ducts present shorter cilia with swollen tips, suggesting defective intraciliary transport. This is associated with signs of chronic pancreatitis, namely acinar-to-ductal metaplasia, acinar proliferation and apoptosis, presence of inflammatory infiltrates, fibrosis and lipomatosis. Our data reveal a tight association between ductal ciliary defects and pancreatitis with perturbed acinar homeostasis and differentiation. Such injuries can account for the increased risk to develop pancreatic cancer in Peutz-Jeghers patients who carry LKB1 loss-of-function mutations.

c-RAF Ablation Induces Regression of Advanced Kras/Trp53 Mutant Lung Adenocarcinomas by a Mechanism Independent of MAPK Signaling

A quarter of all solid tumors harbor KRAS oncogenes. Yet, no selective drugs have been approved to treat these malignancies. Genetic interrogation of the MAPK pathway revealed that systemic ablation of MEK or ERK kinases in adult mice prevent tumor development but are unacceptably toxic. Here, we demonstrate that ablation of c-RAF expression in advanced tumors driven by Kras^G12V/Trp53 mutations leads to significant tumor regression with no detectable appearance of resistance mechanisms. Tumor regression results from massive apoptosis. Importantly, systemic abrogation of c-RAF expression does not inhibit canonical MAPK signaling, hence, resulting in limited toxicities. These results are of significant relevance for the design of therapeutic strategies to treat K-RAS mutant cancers.

Noonan syndrome: lessons learned from genetically modified mouse models

Noonan syndrome is a RASopathy that results from activating mutations in different members of the RAS/MAPK signaling pathway. At least eleven members of this pathway have been found mutated, PTPN11 being the most frequently mutated gene affecting about 50% of the patients, followed by SOS1 (10%), RAF1 (10%) and KRAS (5%). Recently, even more infrequent mutations have been newly identified by next generation sequencing. This spectrum of mutations leads to a broad variety of clinical symptoms such as cardiopathies, short stature, facial dysmorphia and neurocognitive impairment. The genetic variability of this syndrome makes it difficult to establish a genotype-phenotype correlation, which will greatly help in the clinical management of the patients. Areas covered: Studies performed with different genetically engineered mouse models (GEMMs) developed up to date. Expert commentary: GEMMs have helped us understand the role of some genes and the effect of the different mutations in the development of the syndrome. However, few models have been developed and more characterization of the existing ones should be performed to learn about the impact of the different modifiers in the phenotypes, the potential cancer risk in patients, as well as preventative and therapeutic strategies.

Metastatic Lung Cancer and Distress: Use of the Distress Thermometer for Patient Assessment

BACKGROUND

Patients with metastatic lung cancer experience high levels of distress related to their disease trajectory and treatment. Oncology nurses are experts in patient care and symptom management, giving them an opportunity to screen and treat patients' distress.
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OBJECTIVES

The objectives of this study were to screen patients for distress and manage their symptoms to positively affect their quality of life, treatment adherence, and clinical outcomes, and to reduce healthcare costs. 
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METHODS

This quality improvement project was conducted to pilot the Distress Thermometer (DT) into the care of patients with thoracic cancer and to evaluate the effect of a multifaceted intervention, consisting of a patient education pamphlet and a nurse coaching call, on distress levels. 
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FINDINGS

Severe distress was reported in more than half the patients. A paired-sample t test revealed a significant decrease in distress scores following the intervention.

Mechanisms underlying cognitive deficits in a mouse model for Costello Syndrome are distinct from other RASopathy mouse models

RASopathies, characterized by germline mutations in genes encoding proteins of the RAS-ERK signaling pathway, show overlapping phenotypes, which manifest themselves with a varying severity of intellectual disability. However, it is unclear to what extent they share the same downstream pathophysiology that underlies the cognitive deficits. Costello syndrome (CS) is a rare RASopathy caused by activating mutations in the HRAS gene. Here we investigated the mechanisms underlying the cognitive deficits of HRas G12V/G12V mice. HRas G12V/G12V mice showed robust upregulation of ERK signaling, neuronal hypertrophy, increased brain volume, spatial learning deficits, and impaired mGluR-dependent long-term depression (LTD). In contrast, long-term potentiation (LTP), which is affected in other RASopathy mouse models was unaffected. Treatment with lovastatin, a HMG-CoA-Reductase inhibitor which has been shown to rescue the behavioral phenotypes of mouse models of NF1 and Noonan syndrome, was unable to restore ERK signaling and the cognitive deficits of HRas G12V/G12V mice. Administration of a potent mitogen-activated protein kinase (MEK) inhibitor rescued the ERK upregulation and the mGluR-LTD deficit of HRas G12V/G12V mice, but failed to rescue the cognitive deficits. Taken together, this study indicates that the fundamental molecular and cellular mechanisms underlying the cognitive aspects of different RASopathies are remarkably distinct, and may require disease specific treatments.

Effective Cancer Risk Communication to Prevent Disparities in the Era of Precision Medicine

As genetics and genomics become part of mainstream Medicine, these advances have the potential to reduce or exacerbate health disparities. Gaps in effective communication (where all parties share the same meaning) are widely recognized as a major contributor to health disparities. The purpose of this study was to examine cancer genetic counselor-patient communication, to assess its effectiveness from the patient perspective, and to pilot intervention strategies to improve it. We used multiple inductive methods, including standard ethnographic techniques to systematically observe and audio-record genetic counseling sessions, and qualitative interviews with observed patients using the audio recordings to stimulate recall and probe specific aspects of the communication. Data analyses were conducted using grounded theory. We observed 64 English-, 35 Spanish- and 25 Cantonese- speaking public hospital patients (n = 124) and 10 Genetic Counselors in 170 appointments, and interviewed 49 patients who had been offered testing. We identified a fundamental mismatch between the information provided by genetic counselors and the information desired and meaningful to patients. Several components of the communication that contributed to this mismatch and often resulted in ineffective communication included: (1) too much information; (2) complex terminology and conceptually difficult presentation of information; (3) information perceived as not relevant by the patient; (4) unintentional inhibition of patient engagement and question-asking; (5) vague discussions of screening and prevention recommendations. To address these communication barriers, we adapted from other fields of Medicine to the genetic counseling context and pilot tested evidence-based strategies for effective communication with limited literacy patients. Our findings indicate a need to transform the standard model of hereditary cancer risk communication. The increasing access of diverse populations to genetic services, high rates of limited health literacy in the US, and growing complexity of genetic information have created a perfect storm. If not directly addressed, this convergence can be expected to exacerbate health disparities in the genomic age.

Abstract P3-11-04: Adapting evidenced based strategies for effective communication in cancer genetic counseling

This abstract was withdrawn by the authors.

Common Telomere Changes during In Vivo Reprogramming and Early Stages of Tumorigenesis

Reprogramming of differentiated cells into induced pluripotent stem cells has been recently achieved in vivo in mice. Telomeres are essential for chromosomal stability and determine organismal life span as well as cancer growth. Here, we study whether tissue dedifferentiation induced by in vivo reprogramming involves changes at telomeres. We find telomerase-dependent telomere elongation in the reprogrammed areas. Notably, we found highly upregulated expression of the TRF1 telomere protein in the reprogrammed areas, which was independent of telomere length. Moreover, TRF1 inhibition reduced in vivo reprogramming efficiency. Importantly, we extend the finding of TRF1 upregulation to pathological tissue dedifferentiation associated with neoplasias, in particular during pancreatic acinar-to-ductal metaplasia, a process that involves transdifferentiation of adult acinar cells into ductal-like cells due to K-Ras oncogene expression. These findings place telomeres as important players in cellular plasticity both during in vivo reprogramming and in pathological conditions associated with increased plasticity, such as cancer.

Violet/blue light activates Nrf2 signaling and modulates the inflammatory response of THP-1 monocytes

Several studies suggest that light in the UVA range (320–400 nm) activates signaling pathways that are anti-inflammatory and antioxidative.

H-Ras and K-Ras Oncoproteins Induce Different Tumor Spectra When Driven by the Same Regulatory Sequences

Genetic studies in mice have provided evidence that H-Ras and K-Ras proteins are bioequivalent. However, human tumors display marked differences in the association of RAS oncogenes with tumor type. Thus, to further assess the bioequivalence of oncogenic H-Ras and K-Ras, we replaced the coding region of the murine K-Ras locus with H-Ras^G12V oncogene sequences. Germline expression of H-Ras^G12V or K-Ras^G12V from the K-Ras locus resulted in embryonic lethality. However, expression of these genes in adult mice led to different tumor phenotypes. Whereas H-Ras^G12V elicited papillomas and hematopoietic tumors, K-Ras^G12V induced lung tumors and gastric lesions. Pulmonary expression of H-Ras^G12V created a senescence-like state caused by excessive MAPK signaling. Likewise, H-Ras^G12V but not K-Ras^G12V induced senescence in mouse embryonic fibroblasts. Label-free quantitative analysis revealed that minor differences in H-Ras^G12V expression levels led to drastically different biological outputs, suggesting that subtle differences in MAPK signaling confer nonequivalent functions that influence tumor spectra induced by RAS oncoproteins. Cancer Res; 77(3); 707-18. ©2016 AACR.