Yonkus, Jennifer A.

Abstract Background: The transcriptional cofactor Yes-associated protein (YAP) is activated in CCA pathophysiology. While canonical regulation by the Hippo pathway resulting in phosphorylation at serine 127 (S127) is inhibitory, SRC-family kinases (SFKs) phosphorylate YAP at tyrosine 357 (Y357), causing activation. Previously, cholangiocytes, hepatic progenitor cells (HPCs), and even mature hepatocytes were suggested as potential cells of origin of CCA, which highlights the plasticity in the liver. However, the role of YAP activation in selecting the cell of origin and lineage commitment during hepatobiliary oncogenesis is unknown. Aim: To determine if YAP Y357 phosphorylation is required for CCA tumorigenesis, we utilized an in vivo model. Unexpectedly, a shift in tumor phenotype to hepatocellular carcinoma (HCC) was identified. Subsequently, we further explored cell signaling and cell of origin contributions to this phenotypic switch. Method: C57BL/6 mice underwent biliary transfection with Sleeping Beauty transposase and transposons encoding myr-AKT and either YAP S127A (YAP-S) or YAP S127A/Y357F (YAP-SY), followed by IL-33 treatment. Tumor nodule count, histologic classification, and liver-to-body ratio were assessed at necropsy after 10 weeks. RNA sequencing and ingenuity pathway analysis (IPA) were performed on HCC and CCA nodules. To determine the cell of origin, tumors were generated in lineage tracing mice (Rosa26 mT/mG mice treated with AAV8-TBG-Cre). Finally, two tumor-derived cell lines with YAP-SY and constitutive AKT expression were isolated. Results: Both YAP-S and YAP-SY models developed similar tumor numbers and bulk. YAP-S mice generated frequent CCA (25.3%) in addition to combined HCC-CCA (cHCC-CCA) tumors (10.7%) and HCC (64%), whereas YAP-SY mice developed predominantly HCC (86.7%), with rare CCA (8.8%) and mixed tumors (4.5%). Transcriptome analysis identified 3,367 differentially expressed genes (DEGs) between HCC from YAP-SY mice and CCA from YAP-S mice. Notably, YAP-regulated genes had decreased expression in the HCC from YAP-SY mice. IPA revealed key upstream regulators, including cytokines and growth factors (e.g., TGFB1, TNF, INFG, CSF2, IL6, IL1B, IL4) and transcription factors (e.g., TP53, JUN, SP1, NFKBIA, STAT3). Lineage tracing demonstrated HCC originated from hepatocytes and CCA from cholangiocytes in both models. Finally, gene expression analysis of novel syngeneic cancer cell lines from YAP-SY mice showed mixed features of both HCC and CCA. Conclusion: In this murine model, we found that sub-maximal YAP activation is associated with increased formation of HCC from hepatocytes, while a higher level of YAP activation due to YAP Y357 phosphorylation is associated with efficient formation of CCA. We identified cytokines and growth factors that may orchestrate this phenotypic switch. Finally, we developed novel syngeneic cancer cell lines with cHCC-CCA characteristics. Citation Format: Muhammed D. Aksu,Jayla T. Millender,Ryan D. Watkins,Jennifer A. Yonkus,EeeLN H. Buckarma,Nathan W. Werneburg,Daniel R. O'Brien,Chantal E. McCabe,Rondell P. Graham,Gregory J. Gores,Rory L. Smoot,Caitlin B. Conboy. YAP tyrosine phosphorylation regulates lineage commitment in liver tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1457.

Cholangiocarcinoma (CCA) is a highly aggressive form of liver cancer and is an increasing cause of cancer‐related death worldwide. Despite its increasing incidence globally and alarming mortality, treatment options for CCA have largely remained unchanged, stressing the importance of developing new effective therapies. YAP activation is common in CCA, and its major transcriptional signaling partners are the TEAD proteins. CA3 is a small‐molecule YAP‐TEAD disrupter discovered utilizing a TEAD reporter assay. Utilizing CCA, gastric cancer cell lines, and patient‐derived xenograft models (PDX), we demonstrate that CA3 is effective in inducing cell death and delaying tumor growth in both FGFR2 fusion and wild‐type models. CA3 was associated with on‐target decreases in YAP‐TEAD target gene expression, TEAD reporter activity, and overall TEAD levels. Hippo pathway signaling was not altered as there was no change in YAP phosphorylation status in the cells exposed to CA3. RNA sequencing of gastric cancer and CCA models demonstrated upregulation of an androgen receptor–mediated transcriptional program following exposure to CA3 in five unique models tested. Consistent with this upstream regulator analysis, CA3 exposure in CCA cells was associated with increased AR protein levels, and combinatorial therapy with CA3 and androgen receptor blockade was associated with increased cancer cell death. CA3 behaves functionally as a YAP‐TEAD disrupter in the models tested and demonstrated therapeutic efficacy. Exposure to CA3 was associated with compensatory androgen receptor signaling and dual inhibition improved the therapeutic effect.

Objective: The aim of this study is to determine perioperative outcomes and the patency of interposition conduits for visceral arterial reconstruction in this setting. Background: Visceral arterial encasement in locally advanced pancreatic cancer was historically a contraindication for surgery. With modern, effective neoadjuvant strategies, our recent experience has made advanced vascular resection and reconstruction feasible in selected patients. Methods: A retrospective review was performed of patients undergoing pancreatic tumor resection with en bloc arterial resection and interposition revascularization between June 2002 and October 2022. Endpoints included graft patency, vascular-related complications, reinterventions, morbidity, and mortality. Results: Visceral arterial reconstruction with interposition grafting was performed in 111 patients undergoing en bloc arterial resections for pancreatic cancer. Graft types included autologous arterial conduits (n=66, 58 superficial femoral arteries (SFA) and 8 splenic arteries), cryopreserved arterial allografts (n=24), autologous saphenous veins (n=12), synthetic conduits (n=8), and composite autologous artery and synthetic (n=1). Perioperative 90-day mortality decreased significantly over time to 5% in the last 6 years. Vascular complications related to arterial reconstruction occurred in 11% (n=12) and included pseudoaneurysm (n=6), graft thrombus (n=2), stenosis requiring reintervention (n=2), hepatic failure (n=1), and hepatic and intestinal ischemia (n=1). Nine (8%) patients underwent vascular-related reinterventions. After a median follow-up of 17 months, primary patency was 81% for the entire cohort and was highest in the SFA group (95%). The donor limb/harvest site complication rate was 8% with 100% primary patency. Conclusion: Visceral arterial resection with interposition reconstruction for locally advanced pancreatic cancer can be performed with acceptable vascular morbidity and durable patency. Autologous SFA was the most suitable conduit for reconstructions in our experience, with the highest primary patency.

Abstract A major hurdle to the application of precision oncology in pancreatic cancer is the lack of molecular stratification approaches and targeted therapy for defined molecular subtypes. In this work, we sought to gain further insight and identify molecular and epigenetic signatures of the Basal-like A pancreatic ductal adenocarcinoma (PDAC) subgroup that can be applied to clinical samples for patient stratification and/or therapy monitoring. We generated and integrated global gene expression and epigenome mapping data from patient-derived xenograft models to identify subtype-specific enhancer regions that were validated in patient-derived samples. In addition, complementary nascent transcription and chromatin topology (HiChIP) analyses revealed a Basal-like A subtype-specific transcribed enhancer program in PDAC characterized by enhancer RNA (eRNA) production that is associated with more frequent chromatin interactions and subtype-specific gene activation. Importantly, we successfully confirmed the validity of eRNA detection as a possible histologic approach for PDAC patient stratification by performing RNA-ISH analyses for subtype-specific eRNAs on pathologic tissue samples. Thus, this study provides proof-of-concept that subtype-specific epigenetic changes relevant for PDAC progression can be detected at a single-cell level in complex, heterogeneous, primary tumor material. Implications: Subtype-specific enhancer activity analysis via detection of eRNAs on a single-cell level in patient material can be used as a potential tool for treatment stratification.

BACKGROUND: Accurate staging prior to resection of pancreatic ductal adenocarcinoma (PDAC) is imperative to avoid unnecessary operative morbidity and oncologic futility in patients with occult intra-abdominal distant metastases. We aimed to determine the diagnostic yield of staging laparoscopy (SL) and to identify factors associated with increased risk of positive laparoscopy (PL) in the modern era. STUDY DESIGN: Patients with radiographically localized PDAC who underwent SL from 2017 to 2021 were retrospectively reviewed. The yield of SL was defined as the proportion of patients with PL, including gross metastases and/or positive peritoneal cytology. Factors associated with PL were assessed using univariate analysis and multivariable logistic regression. RESULTS: Of 1,004 patients who underwent SL, 180 (18%) had PL due to gross metastases (n = 140) and/or positive cytology (n = 96). Patients who had neoadjuvant chemotherapy prior to laparoscopy had lower rates of PL (14% vs 22%, p = 0.002). When the analysis was restricted to chemo-naive patients who had concurrent peritoneal lavage performed, 95 of 419 patients (23%) had PL. In multivariable analysis, PL was associated with younger (<60) age, indeterminate extrapancreatic lesions on preoperative imaging, body/tail tumor location, larger tumor size, and elevated serum CA 19-9 (all p < 0.05). Among patients with no indeterminate extrapancreatic lesions on preoperative imaging, the rate of PL ranged from 1.6% in patients with no risk factors to 42% in young patients with large body/tail tumors and elevated serum CA 19-9. CONCLUSIONS: The rate of PL in patients with PDAC remains high in the modern era. SL with peritoneal lavage should be considered for the majority of patients prior to resection, specifically those with high-risk features, and ideally prior to neoadjuvant chemotherapy.

Objective Pancreatic ductal adenocarcinoma (PDAC) displays a remarkable propensity towards therapy resistance. However, molecular epigenetic and transcriptional mechanisms enabling this are poorly understood. In this study, we aimed to identify novel mechanistic approaches to overcome or prevent resistance in PDAC. Design We used in vitro and in vivo models of resistant PDAC and integrated epigenomic, transcriptomic, nascent RNA and chromatin topology data. We identified a JunD-driven subgroup of enhancers, called interactive hubs (iHUBs), which mediate transcriptional reprogramming and chemoresistance in PDAC. Results iHUBs display characteristics typical for active enhancers (H3K27ac enrichment) in both therapy sensitive and resistant states but exhibit increased interactions and production of enhancer RNA (eRNA) in the resistant state. Notably, deletion of individual iHUBs was sufficient to decrease transcription of target genes and sensitise resistant cells to chemotherapy. Overlapping motif analysis and transcriptional profiling identified the activator protein 1 (AP1) transcription factor JunD as a master transcription factor of these enhancers. JunD depletion decreased iHUB interaction frequency and transcription of target genes. Moreover, targeting either eRNA production or signaling pathways upstream of iHUB activation using clinically tested small molecule inhibitors decreased eRNA production and interaction frequency, and restored chemotherapy responsiveness in vitro and in vivo. Representative iHUB target genes were found to be more expressed in patients with poor response to chemotherapy compared with responsive patients. Conclusion Our findings identify an important role for a subgroup of highly connected enhancers (iHUBs) in regulating chemotherapy response and demonstrate targetability in sensitisation to chemotherapy.

Mixed acinar neuroendocrine carcinoma of the pancreas (MANEC-P) is an extremely rare malignancy with a poor prognosis. However, epidemiological estimates of MANEC-P remain unknown. This study aimed to estimate and compare the incidence, prevalence, and cancer-specific survival (CSS) of MANEC-P in the United States (US). Patients with MANEC-P were identified through the Surveillance, Epidemiology, and End Results (SEER) and National Program of Cancer Registries databases between 2000–2017. The primary outcomes included age-adjusted incidence rate, limited-duration prevalence, and CSS. A total of 630 patients were identified for the incidence analysis and 149 for the prevalence and CSS analyses. The MANEC-P incidence rate was 0.011 per 100,000 individuals, which was the lowest among pancreatic cancer histologic subtypes. The incidence rate was significantly higher in men and Black races and peaked at 75–79 years of age. The incidence rate was the lowest in the midwestern region (0.009) and the highest in the northeastern US (0.013). The 17-year prevalence was 0.00005%, indicating that 189 patients were alive in the United States at the beginning of 2018. The median CSS of MANEC-P was estimated to be 41 (23, 69) months. In conclusion, MANEC-P is very rare, and its incidence rate has been steady in the US over the last two decades. MANEC-P has a poor prognosis and is the 5th leading cause of pancreatic cancer-related death in the US.

Background A gap remains in the role of neoadjuvant therapy for patients with ILC. Method Single-institution retrospective review of patients with ILC who received neoadjuvant therapy between 2008 and 2019. Results 141 patients met inclusion criteria: 71 neoadjuvant chemotherapy (NACT) and 70 neoadjuvant endocrine therapy (NET). 7/71 (9.9%) patients had a pCR following NACT compared to 1/70 (1.4%) with NET ( P = .063). pCR was observed in 5/18 (27.8%) patients with Her2Neu-positive disease following NACT, compared to 2/53 (3.8%) with Her2Neu-negative disease ( P = .01). For luminal B tumors, median Ki-67 decrease was similar following NACT and NET (18.3 vs 16.3, P = .26). T category decreased in 59 (42.1%) patients following neoadjuvant therapy, increased in 9 (6.4%), and was unchanged in 72 (51.4%). More patients had an increase (28.6%) than decrease (12.1%) in their N category, including 13/60 (21.7%) who were clinically node-negative at diagnosis and identified to have node-positive disease following neoadjuvant therapy, at definitive surgery. Conclusion In Her2Neu-negative ILC, the potential of a pCR with NACT or NET is low. Most patients’ nodal status and tumor size remain unchanged. There is a potential for pathologic stage to be higher at surgery compared to the clinical stage prior to neoadjuvant therapy.

Background: Neoadjuvant therapy (NAT) is used in borderline resectable/locally advanced (BR/LA) pancreatic ductal adenocarcinoma (PDAC). Anatomic imaging (CT/MRI) poorly predicts response, and biochemical (CA 19-9) markers are not useful (nonsecretors/nonelevated) in many patients. Pathologic response highly predicts survival post-NAT, but is only known postoperatively. Because metabolic imaging (FDG-PET) reveals primary tumor viability, this study aimed to evaluate our experience with preoperative FDG-PET in patients with BR/LA PDAC in predicting NAT response and survival. Methods: We reviewed all patients with resected BR/LA PDAC who underwent NAT with FDG-PET within 60 days of resection. Pre- and post-NAT metabolic (FDG-PET) and biochemical (CA 19-9) responses were dichotomized in addition to pathologic responses. We compared post-NAT metabolic and biochemical responses as preoperative predictors of pathologic responses and recurrence-free survival (RFS) and overall survival (OS). Results: We identified 202 eligible patients. Post-NAT, 58% of patients had optimization of CA 19-9 levels. Major metabolic and pathologic responses were present in 51% and 38% of patients, respectively. Median RFS and OS times were 21 and 48.7 months, respectively. Metabolic response was superior to biochemical response in predicting pathologic response (area under the curve, 0.86 vs 0.75; P <.001). Metabolic response was the only univariate preoperative predictor of OS (odds ratio, 0.25; 95% CI, 0.13–0.40), and was highly correlated ( P =.001) with pathologic response as opposed to biochemical response alone. After multivariate adjustment, metabolic response was the single largest independent preoperative predictor ( P <.001) for pathologic response (odds ratio, 43.2; 95% CI, 16.9–153.2), RFS (hazard ratio, 0.37; 95% CI, 0.2–0.6), and OS (hazard ratio, 0.21; 95% CI, 0.1–0.4). Conclusions: Among patients with post-NAT resected BR/LA PDAC, FDG-PET highly predicts pathologic response and survival, superior to biochemical responses alone. Given the poor ability of anatomic imaging or biochemical markers to assess NAT responses in these patients, FDG-PET is a preoperative metric of NAT efficacy, thereby allowing potential therapeutic alterations and surgical treatment decisions. We suggest that FDG-PET should be an adjunct and recommended modality during the NAT phase of care for these patients.

Disrupted liver regeneration following hepatectomy represents an “undruggable” clinical challenge associated with poor patient outcomes. Yes-associated protein (YAP), a transcriptional coactivator that is repressed by the Hippo pathway, is instrumental in liver regeneration. We have previously described an alternative, Hippo-independent mechanism of YAP activation mediated by downregulation of protein tyrosine phosphatase nonreceptor type 11 (PTPN11, also known as SHP2) inhibition. Herein, we examined the effects of YAP activation with a selective SHP1/SHP2 inhibitor, NSC-87877, on liver regeneration in murine partial hepatectomy models. In our studies, NSC-87877 led to accelerated hepatocyte proliferation, improved liver regeneration, and decreased markers of injury following partial hepatectomy. The effects of NSC-87877 were lost in mice with hepatocyte-specific Yap/Taz deletion, and this demonstrated dependence on these molecules for the enhanced regenerative response. Furthermore, administration of NSC-87877 to murine models of nonalcoholic steatohepatitis was associated with improved survival and decreased markers of injury after hepatectomy. Evaluation of transcriptomic changes in the context of NSC-87877 administration revealed reduction in fibrotic signaling and augmentation of cell cycle signaling. Cytoprotective changes included downregulation of Nr4a1 , an apoptosis inducer. Collectively, the data suggest that SHP2 inhibition induces a pro-proliferative and cytoprotective enhancement of liver regeneration dependent on YAP.