Inactivation of TGFβ receptor II signalling in pancreatic epithelial cells promotes acinar cell proliferation, acinar-to-ductal metaplasia and fibrosis during pancreatitis

TGFβ and Hippo Signaling Pathways Coordinate to Promote Acinar to Ductal Metaplasia in Human Pancreas

BACKGROUND & AIMS

Acinar-to-ductal metaplasia (ADM) serves as a precursor event in the development of pancreatic ductal adenocarcinoma (PDAC) upon constitutive environmental and genetical stress. While the role of ADM in PDAC progression has been established, the molecular mechanisms underlying human ADM remain elusive. We previously demonstrated the induction of ADM in human acinar cells through the transforming growth factor beta (TGFβ) signaling pathway. We aim to investigate the interaction between TGFβ and Hippo pathways in mediating ADM.

METHODS

RNA-sequencing was conducted on sorted normal primary human acinar, ductal, and AD (acinar cells that have undergone ADM) cells. ATAC-seq analysis was utilized to reveal the chromatin accessibility in these three cell types. ChIP-Seq of YAP1, SMAD4, and H3K27ac was performed to identify the gene targets of YAP1 and SMAD4. The role of YAP1/TAZ in ADM-driven cell proliferation, as well as in oncogenic KRAS driven proliferation, was assessed using sphere formation assay.

RESULTS

AD cells have a unique transcription profile, with upregulated genes in open chromatin states in acinar cells. YAP1 and SMAD4 co-occupy the loci of ADM-related genes, including PROM1, HES1, and MMP7, co-regulating biological functions such as cell adhesion, cell migration, and inflammation. Overexpression of YAP1/TAZ promoted acinar cell proliferation but still required the TGFβ pathway. YAP1/TAZ were also crucial for TGFβ-induced sphere formation and were necessary for KRAS-induced proliferation.

CONCLUSIONS

Our study reveals the intricate transition between acinar and AD states in human pancreatic tissues. It unveils the complex interaction between the Hippo and TGF-β pathways during ADM, highlighting the pivotal role of YAP1/TAZ and SMAD4 in PDAC initiation.

Transforming Growth Factor-β Blockade in Pancreatic Cancer Enhances Sensitivity to Combination Chemotherapy

BACKGROUND & AIMS

Transforming growth factor-b (TGFb) plays pleiotropic roles in pancreatic cancer, including promoting metastasis, attenuating CD8 T-cell activation, and enhancing myofibroblast differentiation and deposition of extracellular matrix. However, single-agent TGFb inhibition has shown limited efficacy against pancreatic cancer in mice or humans.

METHODS

We evaluated the TGFβ-blocking antibody NIS793 in combination with gemcitabine/nanoparticle (albumin-bound)-paclitaxel or FOLFIRINOX (folinic acid [FOL], 5-fluorouracil [F], irinotecan [IRI] and oxaliplatin [OX]) in orthotopic pancreatic cancer models. Single-cell RNA sequencing and immunofluorescence were used to evaluate changes in tumor cell state and the tumor microenvironment.

RESULTS

Blockade of TGFβ with chemotherapy reduced tumor burden in poorly immunogenic pancreatic cancer, without affecting the metastatic rate of cancer cells. Efficacy of combination therapy was not dependent on CD8 T cells, because response to TGFβ blockade was preserved in CD8-depleted or recombination activating gene 2 (RAG2-/-) mice. TGFβ blockade decreased total α-smooth muscle actin-positive fibroblasts but had minimal effect on fibroblast heterogeneity. Bulk RNA sequencing on tumor cells sorted ex vivo revealed that tumor cells treated with TGFβ blockade adopted a classical lineage consistent with enhanced chemosensitivity, and immunofluorescence for cleaved caspase 3 confirmed that TGFβ blockade increased chemotherapy-induced cell death in vivo.

CONCLUSIONS

TGFβ regulates pancreatic cancer cell plasticity between classical and basal cell states. TGFβ blockade in orthotropic models of pancreatic cancer enhances sensitivity to chemotherapy by promoting a classical malignant cell state. This study provides scientific rationale for evaluation of NIS793 with FOLFIRINOX or gemcitabine/nanoparticle (albumin-bound) paclitaxel chemotherapy backbone in the clinical setting and supports the concept of manipulating cancer cell plasticity to increase the efficacy of combination therapy regimens.

Clinical significance of pancreatic ductal metaplasia

Pancreatic ductal metaplasia (PDM) is the stepwise replacement of differentiated somatic cells with ductal or ductal-like cells in the pancreas. PDM is usually triggered by cellular and environmental insults. PDM development may involve all cell lineages of the pancreas, and acinar cells with the highest plasticity are the major source of PDM. Pancreatic progenitor cells are also involved as cells of origin or transitional intermediates. PDM is heterogeneous at the histological, cellular, and molecular levels and only certain subsets of PDM develop further into pancreatic intraepithelial neoplasia (PanIN) and then pancreatic ductal adenocarcinoma (PDAC). The formation and evolution of PDM is regulated at the cellular and molecular levels through a complex network of signaling pathways. The key molecular mechanisms that drive PDM formation and its progression into PanIN/PDAC remain unclear, but represent key targets for reversing or inhibiting PDM. Alternatively, PDM could be a source of pancreas regeneration, including both exocrine and endocrine components. Cellular aging and apoptosis are obstacles to PDM-to-PanIN progression or pancreas regeneration. Functional identification of the cellular and molecular events driving senescence and apoptosis in PDM and its progression would help not only to restrict the development of PDM into PanIN/PDAC, but may also facilitate pancreatic regeneration. This review systematically assesses recent advances in the understanding of PDM physiology and pathology, with a focus on its implications for enhancing regeneration and prevention of cancer. © 2022 The Pathological Society of Great Britain and Ireland.

Molecular signaling in pancreatic ductal metaplasia: emerging biomarkers for detection and intervention of early pancreatic cancer

Pancreatic ductal metaplasia (PDM) is the transformation of potentially various types of cells in the pancreas into ductal or ductal-like cells, which eventually replace the existing differentiated somatic cell type(s). PDM is usually triggered by and manifests its ability to adapt to environmental stimuli and genetic insults. The development of PDM to atypical hyperplasia or dysplasia is an important risk factor for pancreatic intraepithelial neoplasia (PanIN) and pancreatic ductal adenocarcinoma (PDA). Recent studies using genetically engineered mouse models, cell lineage tracing, single-cell sequencing and others have unraveled novel cellular and molecular insights in PDM formation and evolution. Those novel findings help better understand the cellular origins and functional significance of PDM and its regulation at cellular and molecular levels. Given that PDM represents the earliest pathological changes in PDA initiation and development, translational studies are beginning to define PDM-associated cell and molecular biomarkers that can be used to screen and detect early PDA and to enable its effective intervention, thereby truly and significantly reducing the dreadful mortality rate of PDA. This review will describe recent advances in the understanding of PDM biology with a focus on its underlying cellular and molecular mechanisms, and in biomarker discovery with clinical implications for the management of pancreatic regeneration and tumorigenesis.

Loss of LAT1 sex-dependently delays recovery after caerulein-induced acute pancreatitis

BACKGROUND

The expression of amino acid transporters is known to vary during acute pancreatitis (AP) except for LAT1 (slc7a5), the expression of which remains stable. LAT1 supports cell growth by importing leucine and thereby stimulates mammalian target of rapamycin (mTOR) activity, a phenomenon often observed in cancer cells. The mechanisms by which LAT1 influences physiological and pathophysiological processes and affects disease progression in the pancreas are not yet known.

AIM

To evaluate the role of LAT1 in the development of and recovery from AP.

METHODS

AP was induced with caerulein (cae) injections in female and male mice expressing LAT1 or after its knockout (LAT1 Cre/LoxP). The development of the initial AP injury and its recovery were followed for seven days after cae injections by daily measuring body weight, assessing microscopical tissue architecture, mRNA and protein expression, protein synthesis, and enzyme activity levels, as well as by testing the recruitment of immune cells by FACS and ELISA.

RESULTS

The initial injury, evaluated by measurements of plasma amylase, lipase, and trypsin activity, as well as the gene expression of dedifferentiation markers, did not differ between the groups. However, early metabolic adaptations that support regeneration at later stages were blunted in LAT1 knockout mice. Especially in females, we observed less mTOR reactivation and dysfunctional autophagy. The later regeneration phase was clearly delayed in female LAT1 knockout mice, which did not regain normal expression of the pancreas-specific differentiation markers recombining binding protein suppressor of hairless-like protein (rbpjl) and basic helix-loop-helix family member A15 (mist1). Amylase mRNA and protein levels remained lower, and, strikingly, female LAT1 knockout mice presented signs of fibrosis lasting until day seven. In contrast, pancreas morphology had returned to normal in wild-type littermates.

CONCLUSION

LAT1 supports the regeneration of acinar cells after AP. Female mice lacking LAT1 exhibited more pronounced alterations than male mice, indicating a sexual dimorphism of amino acid metabolism.

Targeting of Smad7 in Mesenchymal Cells Does Not Exacerbate Fibrosis During Experimental Chronic Pancreatitis

OBJECTIVES

Transforming growth factor-β (TGF-β)-mediated accumulation of extracellular matrix proteins such as collagen I is a common feature of fibrosis. Pancreatic stellate cells play an integral role in the pathogenesis of pancreatitis, and their profibrotic ability is mainly mediated by TGF-β signaling. To specifically address the role of fibrogenic cells in experimental pancreatic fibrosis, we deleted Smad7, the main feedback inhibitor of TGF-β signaling in this cell type in mice.

METHODS

A mouse strain harboring a conditional knockout allele of Smad7 (Smad7fl/fl) with the tamoxifen-inducible inducible Col1a2-CreERT allele was generated and compared with wild-type mice challenged with the cerulein-based model of chronic pancreatitis.

RESULTS

Pancreatic stellate cells lacking Smad7 had significantly increased collagen I and fibronectin production and showed a higher activation level in vitro. Surprisingly, the fibrotic index in the pancreata of treated conditional knockout mice was only slightly increased, without statistical significance. Except for fibronectin, the expression of different extracellular matrix proteins and the numbers of fibroblasts and inflammatory cells were similar between Smad7-mutant and control mice.

CONCLUSIONS

There was no clear evidence that the lack of Smad7 in pancreatic stellate cells plays a major role in experimental pancreatitis, at least in the mouse model investigated here.

Hic-5 is required for activation of pancreatic stellate cells and development of pancreatic fibrosis in chronic pancreatitis

Accumulated evidence suggests that activated pancreatic stellate cells (PSCs) serve as the main source of the extracellular matrix proteins accumulated under the pathological conditions leading to pancreatic fibrosis in chronic pancreatitis (CP). However, little is known about the mechanisms of PSC activation. PSCs have morphologic and functional similarities to hepatic stellate cells, which are activated by hydrogen peroxide-inducible clone-5 (Hic-5), a TGF-β1-induced protein. In this study, we investigated whether Hic-5 activates PSCs, which promote pancreatic fibrosis development in CP. Hic-5-knockout and wild type mice were subjected to caerulein injection to induce CP. Hic-5 expression was strongly upregulated in activated PSCs from human CP tissue and from mouse pancreatic fibrosis in caerulein-induced CP. Hic-5 deficiency significantly attenuated mouse pancreatic fibrosis and PSC activation in the experimental murine CP model. Mechanistically, Hic-5 knock down significantly inhibited the TGF-β/Smad2 signaling pathway, resulting in reduced collagen production and α-smooth muscle actin expression in the activated PSCs. Taken together, we propose Hic-5 as a potential marker of activated PSCs and a novel therapeutic target in CP treatment.

Mechanically stressed cancer microenvironment: Role in pancreatic cancer progression

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies in the world due to its insensitivity to current therapies and its propensity to metastases from the primary tumor mass. This is largely attributed to its complex microenvironment composed of unique stromal cell populations and extracellular matrix (ECM). The recruitment and activation of these cell populations cause an increase in deposition of ECM components, which highly influences the behavior of malignant cells through disrupted forms of signaling. As PDAC progresses from premalignant lesion to invasive carcinoma, this dynamic landscape shields the mass from immune defenses and cytotoxic intervention. This microenvironment influences an invasive cell phenotype through altered forms of mechanical signaling, capable of enacting biochemical changes within cells through activated mechanotransduction pathways. The effects of altered mechanical cues on malignant cell mechanotransduction have long remained enigmatic, particularly in PDAC, whose microenvironment significantly changes over time. A more complete and thorough understanding of PDAC's physical surroundings (microenvironment), mechanosensing proteins, and mechanical properties may help in identifying novel mechanisms that influence disease progression, and thus, provide new potential therapeutic targets.

Hic-5 deficiency protects cerulein-induced chronic pancreatitis via down-regulation of the NF-κB (p65)/IL-6 signalling pathway

Chronic pancreatitis (CP), characterized by pancreatic fibrosis, is a recurrent, progressive and irreversible disease. Activation of the pancreatic stellate cells (PSCs) is considered a core event in pancreatic fibrosis. In this study, we investigated the role of hydrogen peroxide-inducible clone-5 (Hic-5) in CP. Analysis of the human pancreatic tissue samples revealed that Hic-5 was overexpressed in patients with CP and was extremely low in healthy pancreas. Hic-5 was significant up-regulated in the activated primary PSCs independently from transforming growth factor beta stimulation. CP induced by cerulein injection was ameliorated in Hic-5 knockout (KO) mice, as shown by staining of tissue level. Simultaneously, the activation ability of the primary PSCs from Hic-5 KO mice was significantly attenuated. We also found that the Hic-5 up-regulation by cerulein activated the NF-κB (p65)/IL-6 signalling pathway and regulated the downstream extracellular matrix (ECM) genes such as α-SMA and Col1a1. Therefore, we determined whether suppressing NF-κB/p65 alleviated CP by treating mice with the NF-κB/p65 inhibitor triptolide in the cerulein-induced CP model and found that pancreatic fibrosis was alleviated by NF-κB/p65 inhibition. These findings provide evidence for Hic-5 as a therapeutic target that plays a crucial role in regulating PSCs activation and pancreatic fibrosis.

Local hyperthyroidism promotes pancreatic acinar cell proliferation during acute pancreatitis

Proliferation of pancreatic acinar cells is a critical process in the pathophysiology of pancreatic diseases, because limited or defective proliferation is associated with organ dysfunction and patient morbidity. In this context, elucidating the signalling pathways that trigger and sustain acinar proliferation is pivotal to develop therapeutic interventions promoting the regenerative process of the organ. In this study we used genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones to elucidate their role in acinar proliferation following caerulein-mediated acute pancreatitis in mice. In addition, molecular mechanisms mediating the effects of thyroid hormones were identified by genetic and pharmacological inactivation of selected signalling pathways.In this study we demonstrated that levels of the thyroid hormone 3,3',5-triiodo-l-thyronine (T3) transiently increased in the pancreas during acute pancreatitis. Moreover, by using genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones, we showed that T3 was required to promote proliferation of pancreatic acinar cells, without affecting the extent of tissue damage or inflammatory infiltration.Finally, upon genetic and pharmacological inactivation of selected signalling pathways, we demonstrated that T3 exerted its mitogenic effect on acinar cells via a tightly controlled action on different molecular effectors, including histone deacetylase, AKT, and TGFβ signalling.In conclusion, our data suggest that local availability of T3 in the pancreas is required to promote acinar cell proliferation and provide the rationale to exploit thyroid hormone signalling to enhance pancreatic regeneration. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Adult human pancreatic acinar cells dedifferentiate into an embryonic progenitor-like state in 3D suspension culture

Human pancreatic exocrine cells were cultured in 3D suspension and formed pancreatospheres composed of acinar-derived and duct-like cells. We investigated, up to 6 days, the fate of human pancreatic acinar cells using fluorescein-conjugated Ulex Europaeus Agglutinin 1 lectin, a previously published acinar-specific non-genetic lineage tracing strategy. At day 4, fluorescence-activated cell sort for the intracellularly incorporated FITC-conjugated UEA1 lectin and the duct-specific CA19.9 surface marker, distinguished acinar-derived cells (UEA1⁺CA19.9^-) from duct-like cells (UEA1^-CA19.9⁺) and acinar-to-duct-like transdifferentiated cells (UEA1⁺CA19.9⁺). mRNA expression analysis of the acinar-derived (UEA1⁺CA19.9^-) and duct-like (UEA1^-CA19.9⁺) cell fractions with concomitant immunocytochemical analysis of the pancreatospheres revealed acquisition of an embryonic signature in the UEA1⁺CA19.9^- acinar-derived cells characterized by de novo expression of SOX9 and CD142, robust expression of PDX1 and surface expression of GP2. The colocalisation of CD142, a multipotent pancreatic progenitor surface marker, PDX1, SOX9 and GP2 is reminiscent of a cellular state present during human embryonic development. Addition of TGF-beta signalling inhibitor Alk5iII, induced a 28-fold increased KI67-labeling in pancreatospheres, more pronounced in the CD142⁺GP2⁺ acinar-derived cells. These findings with human cells underscore the remarkable plasticity of pancreatic exocrine acinar cells, previously described in rodents, and could find applications in the field of regenerative medicine.

High expression of CCR5 in melanoma enhances epithelial-mesenchymal transition and metastasis via TGFβ1

Chemokine receptors are highly expressed in various cancers and play crucial roles in tumor progression. However, their expression patterns and functions in melanoma are unclear. The present study aimed to identify the chemokine receptors that play critical roles in melanoma progression and unravel the underlying molecular mechanisms. We found that CCR5 was more abundant in melanoma cells than normal cells and was positively associated with tumor malignancy in clinical patients. Animal experiments suggested that CCR5 deficiency in B16/F10 or A375 cells suppressed primary tumor growth and lung metastasis, whereas CCR5 overexpression in B16/F0 cells enhanced primary tumor growth and lung metastasis. CCR5 played a critical role in proliferation and migration of melanoma cells in vitro. Importantly, CCR5 was required for maintenance of the mesenchymal phenotype of metastatic melanoma cells. Mechanistically, CCR5 positively regulated expression of TGFβ1, which in turn induced epithelial-mesenchymal transition and migration via PI3K/AKT/GSK3β signaling. Collectively, our results establish a critical role of CCR5 expressed by melanoma cells in cancer progression and reveal the novel mechanisms controlling this process, which suggests the prognostic value of CCR5 in melanoma patients and provides novel insights into CCR5-targeted strategies for melanoma treatment. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pseudomonas aeruginosa-mannose-sensitive hemagglutinin inhibits pancreatic cancer cell proliferation and induces apoptosis via the EGFR pathway and caspase signaling

Pseudomonas aeruginosa-mannose-sensitive hemagglutinin (PA-MSHA) has demonstrated efficacy against several solid tumors. In this study, we found that PA-MSHA inhibited the proliferation of PANC-1 and SW1990 pancreatic cancer cells, but had no obvious effects on HPDE6-C7 normal human pancreatic duct epithelial cells. Electron microscopy revealed the presence of apoptotic bodies and intracellular vacuole formation in PA-MSHA-treated pancreatic cancer cells. Flow cytometric analysis indicated the rate of apoptosis correlated with the PA-MSHA concentration. We observed a decrease in cell fractions in G0/G1 and G2/M phases, and an increase in the fraction in S phase (p < 0.01). PA-MSHA thus caused cell cycle arrest. Increasing concentrations of PA-MSHA did not alter total levels of EGFR, AKT or ERK, but levels of the corresponding phosphoproteins decreased. PA-MSHA also reduced tumor volume in a xenograft mouse model of pancreatic cancer (p < 0.01). Furthermore, caspase-3 levels decreased while the levels of cleaved caspase-3 increased (p < 0.01). These data suggest that by blocking cell cycle progression, PA-MSHA induces apoptosis and inhibits tumor growth. PA-MSHA-mediated inhibition of EGFR signaling and activation of the caspase pathway may play an important role in the induction of apoptosis in pancreatic cancer cells.

Class I histone deacetylase inhibition improves pancreatitis outcome by limiting leukocyte recruitment and acinar-to-ductal metaplasia

BACKGROUND AND PURPOSE

Pancreatitis is a common inflammation of the pancreas with rising incidence in many countries. Despite improvements in diagnostic techniques, the disease is associated with high risk of severe morbidity and mortality and there is an urgent need for new therapeutic interventions. In this study, we evaluated whether histone deacetylases (HDACs), key epigenetic regulators of gene transcription, are involved in the development of the disease.

EXPERIMENTAL APPROACH

We analysed HDAC regulation during cerulein-induced acute, chronic and autoimmune pancreatitis using different transgenic mouse models. The functional relevance of class I HDACs was tested with the selective inhibitor MS-275 in vivo upon pancreatitis induction and in vitro in activated macrophages and primary acinar cell explants.

KEY RESULTS

HDAC expression and activity were up-regulated in a time-dependent manner following induction of pancreatitis, with the highest abundance observed for class I HDACs. Class I HDAC inhibition did not prevent the initial acinar cell damage. However, it effectively reduced the infiltration of inflammatory cells, including macrophages and T cells, in both acute and chronic phases of the disease, and directly disrupted macrophage activation. In addition, MS-275 treatment reduced DNA damage in acinar cells and limited acinar de-differentiation into acinar-to-ductal metaplasia in a cell-autonomous manner by impeding the EGF receptor signalling axis.

CONCLUSIONS AND IMPLICATIONS

These results demonstrate that class I HDACs are critically involved in the development of acute and chronic forms of pancreatitis and suggest that blockade of class I HDAC isoforms is a promising target to improve the outcome of the disease.

Inflammation-Related Pancreatic Carcinogenesis: Mechanisms and Clinical Potentials in Advances

Chronic inflammation has long been considered critical in pancreatic carcinogenesis, and recently studies showed that some anti-inflammatory agents such as aspirin could potentially be used to attenuate pancreatic carcinogenesis. Several inflammation-related critical transcription factors and pathways such as NF-κB (nuclear factor κ-light-chain enhancer of activated B cells) and reactive oxygen species have been confirmed to be involved in carcinogenesis. However, its underlying mechanisms are far from clear, which largely limits further development of potential anticarcinogenesis drugs. As a result, it is of great importance for us to better understand and gain a better perspective in inflammation-related pancreatic carcinogenesis. In this review, we systematically analyzed recent advances concerning inflammation-related pancreatic carcinogenesis and brought out the possible underlying mechanisms. Potential preventive and therapeutic strategies based on anti-inflammatory agents have also been further discussed.

Reg proteins promote acinar-to-ductal metaplasia and act as novel diagnostic and prognostic markers in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignant tumor. Acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) are both precursor lesions that lead to the development of PDAC. Reg family proteins (Reg1A, 1B, 3A/G, 4) are a group of calcium-dependent lectins that promote islet growth in response to inflammation and/or injuries. The aim of this study was to establish a role for Reg proteins in the development of PDAC and their clinical value as biomarkers. We found that Reg1A and Reg3A/G were highly expressed in the ADM tissues by immunohistochemistry. In the 3-dimensional culture of mouse acinar cells, Reg3A promoted ADM formation with concurrent activation of mitogen-acitvated protein kinase. Upregulation of Reg1A and Reg1B levels was observed as benign ductal epithelium progresses from PanIN to invasive PDAC. Patients with PDAC showed significantly higher serum levels of Reg1A and Reg1B than matching healthy subjects. These results were further validated by the quantification of Reg 1A and 1B mRNA levels in the microdissected tissues (22- and 6-fold increases vs. non-tumor tissues). Interestingly, patients with higher levels of Reg1A and 1B exhibited improved survival rate than those with lower levels. Furthermore, tissue expressions of Reg1A, Reg1B, and Reg4 could differentiate metastatic PDAC in the liver from intrahepatic cholangiocarcinoma with 92% sensitivity and 95% specificity. Overall, our results demonstrate the upregulation of Reg proteins during PDAC development. If validated in larger scale, Reg1A and Reg1B could become clinical markers for detecting early stages of PDAC, monitoring therapeutic response, and/or predicting patient's prognosis.

TGF-β1 promotes acinar to ductal metaplasia of human pancreatic acinar cells

Animal studies suggest that pancreatitis-induced acinar-to-ductal metaplasia (ADM) is a key event for pancreatic ductal adenocarcinoma (PDAC) initiation. However, there has not been an adequate system to explore the mechanisms of human ADM induction. We have developed a flow cytometry-based, high resolution lineage tracing method and 3D culture system to analyse ADM in human cells. In this system, well-known mouse ADM inducers did not promote ADM in human cells. In contrast, TGF-β1 efficiently converted human acinar cells to duct-like cells (AD) in a SMAD-dependent manner, highlighting fundamental differences between the species. Functionally, AD cells gained transient proliferative capacity. Furthermore, oncogenic KRAS did not induce acinar cell proliferation, but did sustain the proliferation of AD cells, suggesting that oncogenic KRAS requires ADM-associated-changes to promote PDAC initiation. This ADM model provides a novel platform to explore the mechanisms involved in the development of human pancreatic diseases.