The senescence-associated secretory phenotype induces cellular plasticity and tissue regeneration.

Senescence is a form of cell cycle arrest induced by stress such as DNA damage and oncogenes. However, while arrested, senescent cells secrete a variety of proteins collectively known as the senescence-associated secretory phenotype (SASP), which can reinforce the arrest and induce senescence in a paracrine manner. However, the SASP has also been shown to favor embryonic development, wound healing, and even tumor growth, suggesting more complex physiological roles than currently understood. Here we uncover timely new functions of the SASP in promoting a proregenerative response through the induction of cell plasticity and stemness. We show that primary mouse keratinocytes transiently exposed to the SASP exhibit increased expression of stem cell markers and regenerative capacity in vivo. However, prolonged exposure to the SASP causes a subsequent cell-intrinsic senescence arrest to counter the continued regenerative stimuli. Finally, by inducing senescence in single cells in vivo in the liver, we demonstrate that this activates tissue-specific expression of stem cell markers. Together, this work uncovers a primary and beneficial role for the SASP in promoting cell plasticity and tissue regeneration and introduces the concept that transient therapeutic delivery of senescent cells could be harnessed to drive tissue regeneration.

A microenvironment-inspired synthetic three-dimensional model for pancreatic ductal adenocarcinoma organoids.

Experimental in vitro models that capture pathophysiological characteristics of human tumours are essential for basic and translational cancer biology. Here, we describe a fully synthetic hydrogel extracellular matrix designed to elicit key phenotypic traits of the pancreatic environment in culture. To enable the growth of normal and cancerous pancreatic organoids from genetically engineered murine models and human patients, essential adhesive cues were empirically defined and replicated in the hydrogel scaffold, revealing a functional role of laminin-integrin α3/α6 signalling in establishment and survival of pancreatic organoids. Altered tissue stiffness-a hallmark of pancreatic cancer-was recapitulated in culture by adjusting the hydrogel properties to engage mechano-sensing pathways and alter organoid growth. Pancreatic stromal cells were readily incorporated into the hydrogels and replicated phenotypic traits characteristic of the tumour environment in vivo. This model therefore recapitulates a pathologically remodelled tumour microenvironment for studies of normal and pancreatic cancer cells in vitro.

Chemotherapy-induced infiltration of neutrophils promotes pancreatic cancer metastasis via Gas6/AXL signalling axis.

OBJECTIVE: Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic disease and cytotoxic chemotherapy is the standard of care treatment for patients with advanced disease. Here, we investigate how the microenvironment in PDAC liver metastases reacts to chemotherapy and its role in metastatic disease progression post-treatment, an area which is poorly understood. DESIGN: The impact of chemotherapy on metastatic disease progression and immune cell infiltrates was characterised using flow and mass cytometry combined with transcriptional and histopathological analysis in experimental PDAC liver metastases mouse models. Findings were validated in patient derived liver metastases and in an autochthonous PDAC mouse model. Human and murine primary cell cocultures and ex vivo patient-derived liver explants were deployed to gain mechanistical insights on whether and how chemotherapy affects the metastatic tumour microenvironment. RESULTS: We show that in vivo, chemotherapy induces an initial infiltration of proinflammatory macrophages into the liver and activates cytotoxic T cells, leading only to a temporary restraining of metastatic disease progression. However, after stopping treatment, neutrophils are recruited to the metastatic liver via CXCL1 and 2 secretion by metastatic tumour cells. These neutrophils express growth arrest specific 6 (Gas6) which leads to AXL receptor activation on tumour cells enabling their regrowth. Disruption of neutrophil infiltration or inhibition of the Gas6/AXL signalling axis in combination with chemotherapy inhibits metastatic growth. Chemotherapy increases Gas6 expression in circulating neutrophils from patients with metastatic pancreatic cancer and recombinant Gas6 is sufficient to promote tumour cell proliferation ex vivo, in patient-derived metastatic liver explants. CONCLUSION: Combining chemotherapy with Gas6/AXL or neutrophil targeted therapy could provide a therapeutic benefit for patients with metastatic pancreatic cancer.

The Effect of PrEP Use Disclosure on Adherence in a Cohort of Adolescent Girls and Young Women in South Africa.

Effective strategies to support PrEP adherence among adolescent girls and young women (AGYW) are needed. We examined PrEP use disclosure and its effect on adherence among 200 AGYW ages 16-25 initiating PrEP in South Africa to help inform these  strategies. We estimated the relative prevalence of high adherence (intracellular tenofovir-diphosphate concentration ≥ 700 fmol/punch) 3- and 6-months after PrEP initiation among those who disclosed vs. did not disclose their PrEP use, both overall and by age. Most AGYW disclosed to a parent (58%), partner (58%), or friend (81%) by month 6. We did not observe a strong effect of disclosure on adherence overall; however, among younger AGYW (≤ 18 years), those who disclosed to a parent were 6.8 times as likely to have high adherence at month 6 than those who did not (95% CI 1.02, 45.56). More work is needed to understand parents' roles as allies and identify ways peers and partners can motivate PrEP use for AGYW.

Implementation strategies for integrating pre-exposure prophylaxis for HIV prevention and family planning services for adolescent girls and young women in Kenya: a qualitative study.

INTRODUCTION: Across sub-Saharan Africa, ministries of health have proposed integrating pre-exposure prophylaxis (PrEP) for HIV prevention into family planning (FP) services to reach adolescent girls and young women (AGYW); however, evidence on effective implementation strategies is still limited. We conducted a qualitative study of integrated PrEP-FP service implementation at two FP clinics in Kisumu, Kenya. METHODS: From June 2017 to May 2020, the Prevention Options for Women Evaluation Research (POWER) study enrolled 1000 sexually active, HIV-negative AGYW age 16 to 25. Actions taken to implement PrEP were captured prospectively in 214 monitoring and evaluation documents and 15 interviews with PrEP implementers. We analysed data using conventional and directed content analysis, with the latter informed by the Consolidated Framework for Implementation Research (CFIR) and the Expert Recommendations for Implementing Change (ERIC) compilation. RESULTS: POWER deployed a variety of implementation strategies to train and educate stakeholders (e.g., having new providers shadow PrEP providers); develop stakeholder interrelationships (e.g., organizing support teams with protected time to reflect on implementation progress and make refinements); provide technical assistance; and change physical infrastructure and workflow. Although these strategies reportedly influenced contextual factors across four of the five CFIR domains, they primarily interacted with contextual factors relevant to inner setting, especially implementation climate and readiness for implementation. Overall, implementing PrEP proved easier and less labor-intensive at a private, youth-friendly clinic than a public FP clinic, largely because the baseline structural characteristics (e.g., space, workflow) and organizational mission of the former were more conducive to offering AGYW-centered care. Nevertheless, adoption of PrEP delivery among non-study staff at both sites was low, likely due to the widespread perception that PrEP was not within their scope of work. CONCLUSIONS: Some FP clinics may be "lower-hanging fruit" than others for PrEP implementation. Approaching PrEP implementation as a behavioral intervention for FP providers may help ensure that providers have the requisite capability, opportunity, and motivation to adopt the clinical innovation. In particular, PrEP implementers should assess the need for implementation strategies that support providers' clinical decision-making, establish worker expectations and accountability, and address workload constraints. TRIAL REGISTRATION: Clinical Trial Number: NCT03490058 .

Deep Learning-Based Annotation Transfer between Molecular Imaging Modalities: An Automated Workflow for Multimodal Data Integration.

An ever-increasing array of imaging technologies are being used in the study of complex biological samples, each of which provides complementary, occasionally overlapping information at different length scales and spatial resolutions. It is important to understand the information provided by one technique in the context of the other to achieve a more holistic overview of such complex samples. One way to achieve this is to use annotations from one modality to investigate additional modalities. For microscopy-based techniques, these annotations could be manually generated using digital pathology software or automatically generated by machine learning (including deep learning) methods. Here, we present a generic method for using annotations from one microscopy modality to extract information from complementary modalities. We also present a fast, general, multimodal registration workflow [evaluated on multiple mass spectrometry imaging (MSI) modalities, matrix-assisted laser desorption/ionization, desorption electrospray ionization, and rapid evaporative ionization mass spectrometry] for automatic alignment of complex data sets, demonstrating an order of magnitude speed-up compared to previously published work. To demonstrate the power of the annotation transfer and multimodal registration workflows, we combine MSI, histological staining (such as hematoxylin and eosin), and deep learning (automatic annotation of histology images) to investigate a pancreatic cancer mouse model. Neoplastic pancreatic tissue regions, which were histologically indistinguishable from one another, were observed to be metabolically different. We demonstrate the use of the proposed methods to better understand tumor heterogeneity and the tumor microenvironment by transferring machine learning results freely between the two modalities.

A Pilot Evaluation of Expedited Partner Treatment and Partner Human Immunodeficiency Virus Self-Testing Among Adolescent Girls and Young Women Diagnosed With Chlamydia trachomatis and Neisseria gonorrhoeae in Kisumu, Kenya.

BACKGROUND: Expedited partner treatment (EPT) is effective for preventing sexually transmitted infection recurrence, but concerns about intimate partner violence and missed opportunities for human immunology virus (HIV) testing have limited its use in African settings. METHODS: We conducted a pilot prospective evaluation of EPT among adolescent girls and young women (AGYW) accessing HIV preexposure prophylaxis in an implementation project in Kisumu, Kenya. Those with etiologic diagnosis of Chlamydia trachomatis and Neisseria gonorrhoeae were treated and given the option of delivering sexually transmitted infection medication and HIV self-test kits to their current sexual partner(s). At enrollment, we assessed their reasons for declining. Three months after they delivered medication and kits to the partner(s), we assessed their reasons for failing to deliver medication and kits to their partner and reported partner's reactions. RESULTS: Between September 2018 and March 2020, 63 AGYW were enrolled. The majority (59/63 [94%]) accepted EPT, and 50 (79%) of 63 partner HIV self-testing (HIVST). Three quarters (46/59) of those accepting EPT returned for the assessment visit with 41 (89%) of 46 successfully delivering medication to 54 partners, of whom 49 (91%) used it. Seventy percent (35/50) who took partner HIVST kits returned for the assessment, with 80% (28/35) reporting providing kits to 40 partners, of whom 38 (95%) used it. Reported barriers to EPT and partner HIVST uptake among women who declined included anticipated fear that their partner could become angry or violent and loss of relationship. CONCLUSIONS: Both EPT and partner HIVST were acceptable despite noted barriers among Kenyan AGYW with etiologic diagnosis of Chlamydia trachomatis/Neisseria gonorrhoeae and their partners.

The PrEP Journey: Understanding How Internal Drivers and External Circumstances Impact The PrEP Trajectory of Adolescent Girls and Young Women in Cape Town, South Africa.

Despite high risk for HIV, South African adolescent girls and young women (AGYW) experience numerous challenges with adherence to PrEP. To better understand AGYW's motivations for PrEP and factors that impact PrEP adherence, we conducted serial in-depth interviews with 22 South African AGYW during a 12 month prospective study. Interviews explored motivations and initial experiences of PrEP use, patterns of adherence, social support, and reasons for stopping or persisting with PrEP. We also assessed drug levels as a biomarker of adherence; dried blood spots were collected at months 1, 2, 3, 6, and 12 to assess intracellular tenofovir diphosphate levels. An end-user journey analytical approach revealed themes related to behavioral and emotional aspects of use, including multilevel factors leading to divergent PrEP adherence trajectories. Our findings highlight how internal versus external motivations drive PrEP use, as well as how positive identity formation and challenges are handled, which are essential to understand AGYW in their PrEP journeys.

Trajectories of PrEP Adherence Among Young Women Aged 16 to 25 in Cape Town, South Africa.

Despite demonstrated efficacy for HIV prevention, substantial challenges remain for the successful rollout of oral pre-exposure prophylaxis (PrEP), especially among adolescent girls and young women (AGYW). We characterized trajectories of PrEP adherence among 200 AGYW in South Africa and analyzed data from 22 qualitative interviews and 3 focus group discussions for explanatory purposes. Two adherence trajectory groups were identified: 52% with high early adherence that declined after month three and 48% with low adherence throughout. Adherence in the "consistently low" group was related to social support and logistical concerns, while the decrease in the "high declining" group corresponded to a change in the frequency of study visits from monthly to quarterly. PrEP support should be differentiated for those who need more frequent visits and adherence support initially versus later in PrEP use. Visits every month, when needed, should be considered for AGYW who need sustained support later into use.

"Now that PrEP is reducing the risk of transmission of HIV, why then do you still insist that we use condoms?" the condom quandary among PrEP users and health care providers in Kenya.

Communication around condom use in the context of PrEP services presents a potential conundrum for patients and providers. Within the Partners Scale-Up Project, which supports integration of PrEP delivery in HIV care clinics, we interviewed 41 providers and 61 PrEP users and identified themes relating to condom messaging and use. Most providers counselled PrEP initiators to always use both PrEP and condoms, except when trying to conceive. However, others reported contexts and rationales for not emphasizing condom use. Providers reported that PrEP users were sometimes confused, even frustrated, with their insistence on using condoms in addition to PrEP. PrEP users generally regarded PrEP as a more feasible and desirable HIV prevention method than condoms, enabling increased sexual pleasure and conception, and reducing the conflict and stigma associated with condom use. Innovative approaches to condom counselling in PrEP programs are needed.

A community-based mobile clinic model delivering PrEP for HIV prevention to adolescent girls and young women in Cape Town, South Africa.

BACKGROUND: Daily doses of pre-exposure prophylaxis (PrEP) can reduce the risk of acquiring HIV by more than 95 %. In sub-Saharan Africa, adolescent girls and young women (AGYW) are at disproportionately high risk of acquiring HIV, accounting for 25 % of new infections. There are limited data available on implementation approaches to effectively reach and deliver PrEP to AGYW in high HIV burden communities. METHODS: We explored the feasibility and acceptability of providing PrEP to AGYW (aged 16-25 years) via a community-based mobile health clinic (CMHC) known as the Tutu Teen Truck (TTT) in Cape Town, South Africa. The TTT integrated PrEP delivery into its provision of comprehensive sexual and reproductive health services (SRHS). We analyzed data from community meetings and in-depth interviews with 30 AGYW PrEP users to understand the benefits and challenges of PrEP delivery in this context. RESULTS: A total of 585 young women started PrEP at the TTT between July 2017 - October 2019. During in-depth interviews a subset of 30 AGYW described the CMHC intervention for PrEP delivery as acceptable and accessible. The TTT provided services at times and in neighborhood locations where AGYW organically congregate, thus facilitating service access and generating peer demand for PrEP uptake. The community-based nature of the CMHC, in addition to its adolescent friendly health providers, fostered a trusting provider-community-client relationship and strengthened AGYW HIV prevention self-efficacy. The integration of PrEP and SRHS service delivery was highly valued by AGYW. While the TTT's integration in the community facilitated acceptability of the PrEP delivery model, challenges faced by the broader community (community riots, violence and severe weather conditions) also at times interrupted PrEP delivery. CONCLUSIONS: PrEP delivery from a CMHC is feasible and acceptable to young women in South Africa. However, to effectively scale-up PrEP it will be necessary to develop diverse PrEP delivery locations and modalities to meet AGYW HIV prevention needs.

Low costs and opportunities for efficiency: a cost analysis of the first year of programmatic PrEP delivery in Kenya's public sector.

BACKGROUND: In 2017, the Kenyan Ministry of Health integrated provision of pre-exposure prophylaxis (PrEP) into public HIV-1 care clinics as a key component of the national HIV-1 prevention strategy. Estimates of the cost of PrEP provision are needed to inform the affordability and cost-effectiveness of PrEP in Kenya. METHODS: We conducted activity-based micro-costing from the payer perspective to estimate both the financial and economic costs of all resources and activities required to provide PrEP in Kenya's public sector. We estimated total and unit costs in 2019 United States dollars from a combination of project expense reports, Ministry of Health training reports, clinic staff interviews, time-and-motion observations, and routinely collected data from PrEP recipient files from 25 high-volume HIV-1 care clinics. RESULTS: In the first year of programmatic PrEP delivery in 25 HIV-1 care clinics, 2,567 persons initiated PrEP and accrued 8,847 total months of PrEP coverage, accounting for 2 % of total outpatient clinic visits. The total financial cost to the Ministry of Health was $91,175, translating to an average of $10.31 per person per month. The majority (69 %) of financial costs were attributable to PrEP medication, followed by administrative supplies (17 %) and training (9 %). Economic costs were higher ($188,584 total; $21.32 per person per month) due to the inclusion of the opportunity cost of staff time re-allocated to provide PrEP and a proportional fraction of facility overhead. The vast majority (88 %) of the annual $80,811 economic cost of personnel time was incurred during activities to recruit new clients (e.g., discussion of PrEP within HIV-1 testing and counselling services), while the remaining 12 % was for activities related to both initiation and maintenance of PrEP provision (e.g., client consultations, technical advising, support groups). CONCLUSIONS: Integration of PrEP provision into existing public health HIV-1 care service delivery platforms resulted in minimal additional staff burden and low incremental costs. Efforts to improve the efficiency of PrEP provision should focus on reductions in the cost of PrEP medication and extra-clinic demand creation and community sensitization to reduce personnel time dedicated to recruitment-related activities. TRIAL REGISTRATION: ClinicalTrials.gov registration NCT03052010 . Retrospectively registered on February 14, 2017.

Reenvisioning Advising Models: Meeting the Needs of Prelicensure Nursing Students.

ABSTRACT: Effective academic advising is a dynamic process that is linked to student success. In 2015, a private institution in northern New England began the process of reenvisioning academic advisement as a quality improvement goal for program evaluation. A three-tiered model was used that encompassed targeted academic advising during the early foundational period (core coursework), academic advising during intensive theory and clinical coursework, and postgraduation advising targeting NCLEX-RN® support and mentoring. The goal of this advising model is to develop a relationship with students in forming a plan that leads to a self-fulfilling academic journey and life.

The integrin αvß6 drives pancreatic cancer through diverse mechanisms and represents an effective target for therapy.

Pancreatic ductal adenocarcinoma (PDAC) has a 5-year survival rate of less than 4% and desperately needs novel effective therapeutics. Integrin αvß6 has been linked with poor prognosis in cancer but its potential as a target in PDAC remains unclear. We report that transcriptional expression analysis revealed that high levels of ß6 mRNA correlated strongly with significantly poorer survival (n = 491 cases, p = 3.17 × 10-8 ). In two separate cohorts, we showed that over 80% of PDACs expressed αvß6 protein and that paired metastases retained αvß6 expression. In vitro, integrin αvß6 promoted PDAC cell growth, survival, migration, and invasion. Treatment of both αvß6-positive human PDAC xenografts and transgenic mice bearing αvß6-positive PDAC with the αvß6 blocking antibody 264RAD, combined with gemcitabine, significantly reduced tumour growth (p < 0.0001) and increased survival (log-rank test, p < 0.05). Antibody therapy was associated with suppression of tumour cell activity (suppression of pErk growth signals, increased apoptosis seen as activated caspase-3) and suppression of the pro-tumourigenic microenvironment (suppression of TGFß signalling, fewer αSMA-positive myofibroblasts, decreased blood vessel density). These data show that αvß6 promotes PDAC growth through both tumour cell and tumour microenvironment mechanisms and represents a valuable target for PDAC therapy. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Activation and repression by oncogenic MYC shape tumour-specific gene expression profiles.

In mammalian cells, the MYC oncoprotein binds to thousands of promoters. During mitogenic stimulation of primary lymphocytes, MYC promotes an increase in the expression of virtually all genes. In contrast, MYC-driven tumour cells differ from normal cells in the expression of specific sets of up- and downregulated genes that have considerable prognostic value. To understand this discrepancy, we studied the consequences of inducible expression and depletion of MYC in human cells and murine tumour models. Changes in MYC levels activate and repress specific sets of direct target genes that are characteristic of MYC-transformed tumour cells. Three factors account for this specificity. First, the magnitude of response parallels the change in occupancy by MYC at each promoter. Functionally distinct classes of target genes differ in the E-box sequence bound by MYC, suggesting that different cellular responses to physiological and oncogenic MYC levels are controlled by promoter affinity. Second, MYC both positively and negatively affects transcription initiation independent of its effect on transcriptional elongation. Third, complex formation with MIZ1 (also known as ZBTB17) mediates repression of multiple target genes by MYC and the ratio of MYC and MIZ1 bound to each promoter correlates with the direction of response.

Combating pancreatic cancer with PI3K pathway inhibitors in the era of personalised medicine.

Pancreatic ductal adenocarcinoma (PDAC) is among the most deadly solid tumours. This is due to a generally late-stage diagnosis of a primarily treatment-refractory disease. Several large-scale sequencing and mass spectrometry approaches have identified key drivers of this disease and in doing so highlighted the vast heterogeneity of lower frequency mutations that make clinical trials of targeted agents in unselected patients increasingly futile. There is a clear need for improved biomarkers to guide effective targeted therapies, with biomarker-driven clinical trials for personalised medicine becoming increasingly common in several cancers. Interestingly, many of the aberrant signalling pathways in PDAC rely on downstream signal transduction through the mitogen-activated protein kinase and phosphoinositide 3-kinase (PI3K) pathways, which has led to the development of several approaches to target these key regulators, primarily as combination therapies. The following review discusses the trend of PDAC therapy towards molecular subtyping for biomarker-driven personalised therapies, highlighting the key pathways under investigation and their relationship to the PI3K pathway.

Reshaping the Tumor Stroma for Treatment of Pancreatic Cancer.

Pancreatic cancer is accompanied by a fibrotic reaction that alters interactions between tumor cells and the stroma to promote tumor progression. Consequently, strategies to target the tumor stroma might be used to treat patients with pancreatic cancer. We review recently developed approaches for reshaping the pancreatic tumor stroma and discuss how these might improve patient outcomes. We also describe relationships between the pancreatic tumor extracellular matrix, the vasculature, the immune system, and metabolism, and discuss the implications for the development of stromal compartment-specific therapies.

p53 status determines the role of autophagy in pancreatic tumour development.

Macroautophagy (hereafter referred to as autophagy) is a process in which organelles termed autophagosomes deliver cytoplasmic constituents to lysosomes for degradation. Autophagy has a major role in cellular homeostasis and has been implicated in various forms of human disease. The role of autophagy in cancer seems to be complex, with reports indicating both pro-tumorigenic and tumour-suppressive roles. Here we show, in a humanized genetically-modified mouse model of pancreatic ductal adenocarcinoma (PDAC), that autophagy's role in tumour development is intrinsically connected to the status of the tumour suppressor p53. Mice with pancreases containing an activated oncogenic allele of Kras (also called Ki-Ras)--the most common mutational event in PDAC--develop a small number of pre-cancerous lesions that stochastically develop into PDAC over time. However, mice also lacking the essential autophagy genes Atg5 or Atg7 accumulate low-grade, pre-malignant pancreatic intraepithelial neoplasia lesions, but progression to high-grade pancreatic intraepithelial neoplasias and PDAC is blocked. In marked contrast, in mice containing oncogenic Kras and lacking p53, loss of autophagy no longer blocks tumour progression, but actually accelerates tumour onset, with metabolic analysis revealing enhanced glucose uptake and enrichment of anabolic pathways, which can fuel tumour growth. These findings provide considerable insight into the role of autophagy in cancer and have important implications for autophagy inhibition in cancer therapy. In this regard, we also show that treatment of mice with the autophagy inhibitor hydroxychloroquine, which is currently being used in several clinical trials, significantly accelerates tumour formation in mice containing oncogenic Kras but lacking p53.

Activation of the PIK3CA/AKT pathway suppresses senescence induced by an activated RAS oncogene to promote tumorigenesis.

Mutations in both RAS and the PTEN/PIK3CA/AKT signaling module are found in the same human tumors. PIK3CA and AKT are downstream effectors of RAS, and the selective advantage conferred by mutation of two genes in the same pathway is unclear. Based on a comparative molecular analysis, we show that activated PIK3CA/AKT is a weaker inducer of senescence than is activated RAS. Moreover, concurrent activation of RAS and PIK3CA/AKT impairs RAS-induced senescence. In vivo, bypass of RAS-induced senescence by activated PIK3CA/AKT correlates with accelerated tumorigenesis. Thus, not all oncogenes are equally potent inducers of senescence, and, paradoxically, a weak inducer of senescence (PIK3CA/AKT) can be dominant over a strong inducer of senescence (RAS). For tumor growth, one selective advantage of concurrent mutation of RAS and PTEN/PIK3CA/AKT is suppression of RAS-induced senescence. Evidence is presented that this new understanding can be exploited in rational development and targeted application of prosenescence cancer therapies.

Notch3 drives development and progression of cholangiocarcinoma.

The prognosis of cholangiocarcinoma (CC) is dismal. Notch has been identified as a potential driver; forced exogenous overexpression of Notch1 in hepatocytes results in the formation of biliary tumors. In human disease, however, it is unknown which components of the endogenously signaling pathway are required for tumorigenesis, how these orchestrate cancer, and how they can be targeted for therapy. Here we characterize Notch in human-resected CC, a toxin-driven model in rats, and a transgenic mouse model in which p53 deletion is targeted to biliary epithelia and CC induced using the hepatocarcinogen thioacetamide. We find that across species, the atypical receptor NOTCH3 is differentially overexpressed; it is progressively up-regulated with disease development and promotes tumor cell survival via activation of PI3k-Akt. We use genetic KO studies to show that tumor growth significantly attenuates after Notch3 deletion and demonstrate signaling occurs via a noncanonical pathway independent of the mediator of classical Notch, Recombinant Signal Binding Protein for Immunoglobulin Kappa J Region (RBPJ). These data present an opportunity in this aggressive cancer to selectively target Notch, bypassing toxicities known to be RBPJ dependent.