Explore the vast range of titles available.

Background Solid tumors such as pancreatic ductal adenocarcinoma (PDAC) comprise not just tumor cells but also a microenvironment with which the tumor cells constantly interact. Detailed characterization of the cellular composition of the tumor microenvironment is critical to the understanding of the disease and treatment of the patient. Single-cell transcriptomics has been used to study the cellular composition of different solid tumor types including PDAC. However, almost all of those studies used primary tumor tissues. Methods In this study, we employed a single-cell RNA sequencing technology to profile the transcriptomes of individual cells from dissociated primary tumors or metastatic biopsies obtained from patients with PDAC. Unsupervised clustering analysis as well as a new supervised classification algorithm, SuperCT, was used to identify the different cell types within the tumor tissues. The expression signatures of the different cell types were then compared between primary tumors and metastatic biopsies. The expressions of the cell type-specific signature genes were also correlated with patient survival using public datasets. Results Our single-cell RNA sequencing analysis revealed distinct cell types in primary and metastatic PDAC tissues including tumor cells, endothelial cells, cancer-associated fibroblasts (CAFs), and immune cells. The cancer cells showed high inter-patient heterogeneity, whereas the stromal cells were more homogenous across patients. Immune infiltration varies significantly from patient to patient with majority of the immune cells being macrophages and exhausted lymphocytes. We found that the tumor cellular composition was an important factor in defining the PDAC subtypes. Furthermore, the expression levels of cell type-specific markers for EMT + cancer cells, activated CAFs, and endothelial cells significantly associated with patient survival. Conclusions Taken together, our work identifies significant heterogeneity in cellular compositions of PDAC tumors and between primary tumors and metastatic lesions. Furthermore, the cellular composition was an important factor in defining PDAC subtypes and significantly correlated with patient outcome. These findings provide valuable insights on the PDAC microenvironment and could potentially inform the management of PDAC patients.

Key Points Perineural invasion (PNI) is the process through which cancer cells invade the perineural spaces of surrounding nerves and is not simply the movement of cancer cells along a path of low resistance, as was previously thought. PNI is a directed process that involves many signalling molecules from various signalling pathways; these signalling molecules are produced by both the cancer cells and the nerves. Once the cancer cells have invaded the nerves, they are able to thrive within the neuronal spaces. This constitutes a means for the cancer cells to spread to distant locations. The incidence of PNI is particularly high in pancreatic cancer. Although the exact cause for this increased affinity is as yet unclear, the strong neurotropic effects of pancreatic cancer cells are thought to contribute to this phenomenon. Additionally, reciprocal signalling between the pancreatic cancer cells and the surrounding nerves leads to neurogenesis, as well as the increased growth of pancreatic cancer cells. PNI also contributes to the generation of the pain that is experienced by pancreatic cancer patients, and many of the signalling molecules that are involved in PNI are also known to be involved in pain signalling. Thus, we hypothesize that agents targeting these signalling pathways may have the potential to prevent PNI and may help to alleviate pain in patients with pancreatic cancer. Perineural invasion (PNI) is a prominent characteristic of pancreatic cancer that is involved in the generation of pain, and correlates with poor prognosis in most studies. This Review discusses the signalling molecules and pathways that are involved in PNI and whether knowledge of these could be used to alleviate pain and to reduce the incidence of PNI. Perineural invasion (PNI) is a prominent characteristic of pancreatic cancer. PNI is a process whereby cancer cells invade the surrounding nerves, thus providing an alternative route for metastatic spread and pain generation. PNI is thought to be an indicator of aggressive tumour behaviour and has been shown to correlate with poor prognosis of patients with pancreatic cancer. Recent studies demonstrated that some signalling molecules and pathways that are involved in PNI are also involved in pain generation. Targeting these signalling pathways has shown some promise in alleviating pain and reducing PNI, which could potentially improve treatment outcomes for patients with pancreatic cancer.

ROCK, or Rho-associated coiled coil-containing protein kinase, is a member of the AGC kinase family and has been shown to play a role in cell migration, ECM synthesis, stress-fiber assembly, and cell contraction. Increased ROCK expression has been reported in multiple pathological conditions, including cancer. Here, we report increased expression of ROCK 1 in pancreatic tumor epithelial cells as well as in cancer associated fibroblasts (CAF). In our analysis, 62% of tumor samples exhibited ≥2+ in staining intensity by IHC analysis, versus 40% of adjacent normal tissue samples (P<0.0001). Thus, we hypothesized that ROCKs may play a significant role in pancreatic cancer progression, and may serve as a suitable target for treatment. We report a low frequency (4/34) amplification of the ROCK1 gene locus at chromosome 18q11.1 in pancreatic ductal adenocarcinoma (PDAC) patient tissue samples by aCGH analysis. Inhibition of ROCK kinase activity by a small molecule inhibitor (fasudil) resulted in moderate (IC50s of 6-71 μM) inhibition of PDAC cell proliferation, migration, and activation of co-cultured stellate cells. In the KPC mouse model for pancreatic cancer, fasudil decreased tumor collagen deposition. This translated to an enhanced overall survival of the mice and an increase in gemcitabine uptake. Though fasudil may target both the tumor epithelial cells and the CAFs, our findings are consistent with the hypothesis that inhibition of tumor stroma enhances drug penetration and efficacy in PDAC. Overall, our data suggests that ROCK1 may serve as a potential therapeutic target to enhance current treatment regimens for pancreatic cancer.

Perineural invasion (PNI) is thought to be one of the factors responsible for the high rate of tumor recurrence after surgery and the pain generation associated with pancreatic cancer. Signaling via the nerve growth factor (NGF) pathway between pancreatic cancer cells and the surrounding nerves has been implicated in PNI, and increased levels of these proteins have been correlated to poor prognosis. In this study, we examine the molecular mechanism of the NGF signaling pathway in PNI in pancreatic cancer. We show that knocking down NGF or its receptors, TRKA and p75NTR, or treatment with GW441756, a TRKA kinase inhibitor, reduces the proliferation and migration of pancreatic cancer cells in vitro. Furthermore, pancreatic cancer cells migrate towards dorsal root ganglia (DRG) in a co-culture assay, indicating a paracrine NGF signaling between the DRGs and pancreatic cancer cells. Knocking down the expression of NGF pathway proteins or inhibiting the activity of TRKA by GW441756 reduced the migratory ability of Mia PaCa2 towards the DRGs. Finally, blocking NGF signaling by NGF neutralizing antibodies or GW441756 inhibited the neurite formation in PC-12 cells in response to conditioned media from pancreatic cancer cells, indicating a reciprocal signaling pathway between the pancreatic cancer cells and nerves. Our results indicate that NGF signaling pathway provides a potential target for developing molecularly targeted therapies to decrease PNI and reduce pain generation. Since there are several TRKA antagonists currently in early clinical trials they could now be tested in the clinical situation of pancreatic cancer induced pain.

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease with poor survival rates, primarily due to the limited effectiveness of gemcitabine (Gem)-based chemotherapy, as well as the acquisition of chemotherapeutic resistance. Aronia berry extracts (ABEs), abundant in phenolic constituents, have been recently recognized for their anticancer properties as well as their encouraging potential to help overcome chemoresistance in various cancers. In the present study, we explored ABE’s potential to overcome Gem resistance in PDAC and identify specific growth regulatory pathways responsible for its anticancer activity. Through a series of in vitro experiments in gemcitabine-resistant (Gem-R) cells, we elucidated the synergistic interactions between Gem and ABE treatments. Using advanced transcriptomic analysis and network pharmacology, we revealed key molecular pathways linked to chemoresistance and potential therapeutic targets of ABE in Gem-R PDAC cells. Subsequently, the findings from cell culture studies were validated in patient-derived 3D tumor organoids (PDOs). The combination treatment of ABE and Gem demonstrated significant synergism and anticancer effects on cell viability, proliferation, migration, and invasion in Gem-R cells. Transcriptomic analysis revealed a correlation between the NF-Κb signaling pathway and Gem-R (p < 0.05), exhibiting a marked upregulation of MYD88. Additionally, MYD88 exhibited a significant correlation with the overall survival rates in patients with PDAC patients in the TCGA cohort (HR = 1.58, p < 0.05). The MYD88/NF-Κb pathway contributes to chemoresistance by potentially upregulating efflux transporters like P-glycoprotein (P-gp). Our findings revealed that the combined treatment with ABE suppressed the NF-Κb pathway by targeting MYD88 and reducing P-gp expression to overcome Gem resistance. Lastly, the combination therapy proved highly effective in PDOs in reducing both their number and size (p < 0.05). Our study offers previously unrecognized insights into the ability of ABE to overcome Gem resistance in PDAC cells through its targeting of the MYD88/NF-κb/P-gp axis, hence providing a safe and cost-effective adjunctive therapeutic strategy to improve treatment outcomes in PDAC.

Gemcitabine (Gem)-based chemotherapy is one of the first-line treatments for pancreatic ductal adenocarcinoma (PDAC). However, its clinical effect is limited due to development of chemoresistance. Various naturally occurring compounds, including Berberine (BBR), provide an anti-cancer efficacy with time-tested safety, individually and in combination with chemotherapeutic drugs. Accordingly, we hypothesized that BBR might enhance the chemosensitivity to Gem in PDAC. In this study, cell culture studies using MIA PaCa-2 and BxPC-3 cells, followed by analysis in patient-derived organoids were performed to evaluate the anti-cancer effects of BBR in PDAC. Considering that cancer is a significant manifestation of increased chronic inflammatory stress, systems biology approaches are prudent for the identification of molecular pathways and networks responsible for phytochemical-induced anti-cancer activity, we used these approaches for BBR-mediated chemosensitization to Gem. Firstly, Gem-resistant (Gem-R) PDAC cells were established, and the combination of BBR and Gem revealed superior anti-cancer efficacy in Gem-R cells. Furthermore, the combination treatment induced cell cycle arrest and apoptosis in Gem-R PDAC cells. Transcriptomic profiling investigated the Rap1 and PI3K-Akt signaling pathway as a key regulator of Gem-resistance and was a key mediator for BBR-mediated chemosensitization in PDAC cells. All cell culture-based findings were successfully validated in patient-derived organoids. In conclusion, we demonstrate that BBR-mediated reversal of chemoresistance to Gem manifests through Rap1/PI3K-Akt signaling in PDAC.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy in need of new therapeutic options. Using unbiased analyses of super-enhancers (SEs) as sentinels of core genes involved in cell-specific function, here we uncover a druggable SE-mediated RNA-binding protein (RBP) cascade that supports PDAC growth through enhanced mRNA translation. This cascade is driven by a SE associated with the RBP heterogeneous nuclear ribonucleoprotein F, which stabilizes protein arginine methyltransferase 1 (PRMT1) to, in turn, control the translational mediator ubiquitin-associated protein 2-like. All three of these genes and the regulatory SE are essential for PDAC growth and coordinately regulated by the Myc oncogene. In line with this, modulation of the RBP network by PRMT1 inhibition reveals a unique vulnerability in Myc-high PDAC patient organoids and markedly reduces tumor growth in male mice. Our study highlights a functional link between epigenetic regulation and mRNA translation and identifies components that comprise unexpected therapeutic targets for PDAC. The epigenetic mechanisms underlying pancreatic ductal adenocarcinoma (PDAC) are not fully elucidated. Here, the authors reveal a druggable super-enhancer-mediated RNA-binding protein cascade that supports PDAC growth through enhanced mRNA translation.

SIWA318H is a novel monoclonal antibody that selectively targets an advanced glycation end product biomarker found in damaged/dysfunctional cells exhibiting (a) aerobic glycolysis, and (b) oxidative stress. Cells with this biomarker are dysfunctional and are associated with stresses and/or damages relating to aging, cancer and other disease processes. In this study, we evaluated the biological effects and antitumor activity of SIWA318H in preclinical models for pancreatic cancer. SIWA318H binds to pancreatic cancer cells and cancer-associated fibroblasts, as well as tumor xenografts derived from pancreatic cancer patients. Furthermore, SIWA318H induced significant antibody-dependent cell-mediated cytotoxicity (ADCC) against pancreatic cancer cells. In a humanized CD34 + NSG mouse xenograft model for pancreatic cancer, tumors in mice treated with SIWA318H grew significantly slower compared to those in control mice (p < 0.001). After 3 weeks of treatment with SIWA318H, the tumor growth was suppressed by 68.8% and 61.5% for the high and low dose regimens, respectively, when compared to the isotype antibody control (ANOVA p < 0.002). Moreover, a significant increase in complete remission (CR) rate was observed in mice receiving the high dose (60%, p < 0.04) or low dose (77.8%, p < 0.02) of SIWA318H treatment compared with control mice (6.7%). Immunohistochemical analyses of the tumor tissues showed a significant decrease in senescent cells in the tumor microenvironment of SIWA318H treated mice compared to that of control treated mice (p < 0.05). These results provide compelling evidence that SIWA318H is a promising novel therapeutic against pancreatic cancer.

Oncogenic lesions in pancreatic ductal adenocarcinoma (PDAC) hijack the epigenetic machinery in stromal components to establish a desmoplastic and therapeutic resistant tumor microenvironment (TME). Here we identify Class I histone deacetylases (HDACs) as key epigenetic factors facilitating the induction of pro-desmoplastic and pro-tumorigenic transcriptional programs in pancreatic stromal fibroblasts. Mechanistically, HDAC-mediated changes in chromatin architecture enable the activation of pro-desmoplastic programs directed by serum response factor (SRF) and forkhead box M1 (FOXM1). HDACs also coordinate fibroblast pro-inflammatory programs inducing leukemia inhibitory factor (LIF) expression, supporting paracrine pro-tumorigenic crosstalk. HDAC depletion in cancer-associated fibroblasts (CAFs) and treatment with the HDAC inhibitor entinostat (Ent) in PDAC mouse models reduce stromal activation and curb tumor progression. Notably, HDAC inhibition (HDACi) enriches a lipogenic fibroblast subpopulation, a potential precursor for myofibroblasts in the PDAC stroma. Overall, our study reveals the stromal targeting potential of HDACi, highlighting the utility of this epigenetic modulating approach in PDAC therapeutics. The desmoplastic stroma constitutes part of the microenvironment in pancreatic ductal adenocarcinoma. Here the authors show that Class I HDACs regulate the pro-desmoplastic and pro-tumorigenic transcriptional programs to support stromal activation and tumour progression.

Metabolic reprogramming contributes to oncogenesis, tumor growth, and treatment resistance in pancreatic ductal adenocarcinoma (PDAC). Here we report the effects of ( R , S ′)-4′-methoxy-1-naphthylfenoterol (MNF), a GPR55 antagonist and biased β 2 -adrenergic receptor (β 2 -AR) agonist on cellular signaling implicated in proliferation and metabolism in PDAC cells. The relative contribution of GPR55 and β 2 -AR in ( R , S ′)-MNF signaling was explored further in PANC-1 cells. Moreover, the effect of ( R , S ′)-MNF on tumor growth was determined in a PANC-1 mouse xenograft model. PANC-1 cells treated with ( R,S ′)-MNF showed marked attenuation in GPR55 signal transduction and function combined with increased β 2 -AR/Gα s /adenylyl cyclase/PKA signaling, both of which contributing to lower MEK/ERK, PI3K/AKT and YAP/TAZ signaling. ( R,S ′)-MNF administration significantly reduced PANC-1 tumor growth and circulating l -lactate concentrations. Global metabolic profiling of ( R,S ′)-MNF-treated tumor tissues revealed decreased glycolytic metabolism, with a shift towards normoxic processes, attenuated glutamate metabolism, and increased levels of ophthalmic acid and its precursor, 2-aminobutyric acid, indicative of elevated oxidative stress. Transcriptomics and immunoblot analyses indicated the downregulation of gene and protein expression of HIF-1α and c-Myc, key initiators of metabolic reprogramming in PDAC. ( R , S ′)-MNF treatment decreased HIF-1α and c-Myc expression, attenuated glycolysis, shifted fatty acid metabolism towards β-oxidation, and suppressed de novo pyrimidine biosynthesis in PANC-1 tumors. The results indicate a potential benefit of combined GPR55 antagonism and biased β 2 -AR agonism in PDAC therapy associated with the deprogramming of altered cellular metabolism.