Pancreatic Ductal Adenocarcinoma Cells Research Articles

Endosomal Trafficking Bypassed by the RAB5B-CD109 Interplay Promotes Axonogenesis in KRAS-Mutant Pancreatic Cancer.

Perineural invasion (PNI) represents a unique biological feature associated with poor prognosis in pancreatic ductal adenocarcinoma (PDAC), especially in the presence of KRAS mutations. Extracellular vesicle (EV)-packaged circular RNAs (circRNAs) function as essential mediators of tumor microenvironment communication, triggering PDAC cell invasion and distant metastasis. However, the regulatory mechanisms of EV-packaged circRNAs in the PNI of KRAS-mutant PDAC have not yet been elucidated. Herein, a KRASG12D mutation-responsive EV-packaged circRNA, circPNIT, which positively correlated with PNI in PDAC patients is identified. Functionally, KRASG12D PDAC-derived EV-packaged circPNIT promoted axonogenesis and PNI both in vitro and in vivo. Mechanistically, the circPNIT-mediated Rab5B-CD109 interplay bypassed traditional endosomal trafficking to anchor Rab5B to the lipid rafts of multivesicular bodies and packaged circPNIT into CD109+ EVs. Subsequently, CD109+ EVs delivered circPNIT to neurons by binding to TRPV1 and facilitating DSCAML1 transcription-induced axonogenesis, which in turn enhanced the PNI by activating the GFRα1/RET pathway. Importantly, circPNIT-loaded CD109+ EVs are established to dramatically promote PNI in a KRASG12D/+ Trp53R172H/+ Pdx-1-Cre mouse model. Collectively, the findings highlight the mechanism underlying how EV-packaged circRNAs mediate the PNI of KRAS-mutant PDAC cells through the Rab5B endosomal bypass, identifying circPNIT as an effective target for the treatment of neuro-metastatic PDAC.

Epigenetic Activation of the CMTM6-IGF2BP1-EP300 Positive Feedback Loop Drives Gemcitabine Resistance in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with a dismal prognosis. Gemcitabine-based chemotherapy has emerged as a first-line treatment for PDAC. However, the development of gemcitabine resistance often results in therapeutic failure. In order to uncover the underlying mechanisms of gemcitabine resistance, gemcitabine-resistant PDAC cell lines and patient-derived xenograft (PDX) models are established and subjected to RNA sequencing. It is found that CMTM6 is closely related to gemcitabine resistance in PDAC. Multi-omics analysis revealed that EP300-mediated H3K27ac modification is involved in the transcriptional activation of CMTM6, which maintains IGF2BP1 expression by preventing its ubiquitination. The m6A reader IGF2BP1 stabilizes the EP300 and MYC mRNAs by recognizing m6A modifications, forming a positive feedback loop that enhances tumor stemness and ultimately contributes to PDAC resistance. The combined application of the EP300 inhibitor inobrodib and gemcitabine exerts a synergistic effect on PDAC. Overall, these findings reveal that the EP300-CMTM6-IGF2BP1 positive feedback loop facilitates gemcitabine resistance via epigenetic reprogramming and the combined use of inobrodib and gemcitabine represents a promising strategy for overcoming chemoresistance in PDAC, warranting further investigation in clinical trials.

The Far Side of Resistance to RAS Inhibitors.

In this issue, four articles highlight the critical role of nongenetic mechanisms and cell plasticity in mediating resistance to different classes of RAS inhibitors in pancreatic ductal adenocarcinoma and non-small cell lung cancer. See related article by Benitz et al., p. 2162 See related article by Dilly et al., p. 2135 See related article by Araujo et al., p. 2183 See related article by Singhal et al., p. 2122.

Genome-wide microRNA Analysis Identified miR-210-3p Over-expression in Pancreatic Cancer Tissues as a Predictor of their Local Invasiveness.

The severe malignancy of pancreatic ductal adenocarcinoma (PDAC) is mainly due to frequent local invasiveness and distant metastasis. As for local invasiveness, we previously reported that cancer-specific molecular alterations detected on resected PDAC specimen surfaces, so-called molecular surgical margin (MSM) positiveness, were significantly associated with postoperative locoregional recurrence and distant metastasis. However, due to anatomical limitations, achieving adequate surgical margins during pancreatic cancer resection is often challenging. Therefore, predicting local invasiveness based on the primary tumor's gene profile is crucial to avoid positive MSM. Genome-wide miRNA expression profiles were examined and compared between MSM-positive and negative cases. Candidate miRNAs were evaluated in another validation cohort, and their clinicopathological characteristics were examined. Mimic or inhibitor constructs of the candidate miRNA were transfected to PDAC cell lines to evaluate the miRNA function in the pancreatic cancer cell lines and detect the downstream targets. Among some candidates with highly expressed miRNAs in MSM-positive cases by miRNA expression array, recurrence-free survival (RFS) was significantly shorter in the miR-210-3p high expression group (p=0.015). High miR-210-3p was significantly associated with large tumor diameter (p=0.001), anterior invasion positive (p=0.010), and positive lymph node metastasis (p<0.001). miR-210-3p inhibition in PDAC cell lines resulted in decreased proliferation and invasiveness. The iron-sulfur cluster assembly enzyme (ISCU) gene was identified as a target of miR-210-3p. ISCU reduction was significantly observed in PDAC primary tumors with high levels of miR-210-3p, leading to mitochondrial dysfunction in miR-210-3p-overexpressing PDAC cell lines, as demonstrated by glycolysis stress tests. Highly expressed hypoxia-inducible miR-210-3p in primary PDAC tissues induces locally invasive characteristics through mitochondrial dysfunction by suppressing ISCU expression, which may result in poor postoperative RFS outcomes.

Lymphocyte Antigen 6 Family Member D (LY6D) Affects Stem Cell Phenotype and Progression of Pancreatic Adenocarcinoma.

The membrane-bound protein lymphocyte antigen 6 family member D (LY6D), a marker of early B cell lineage is reportedly expressed in several human malignancies and has been implicated in cancer stemness. However, its expression and role in cancer stemness remain largely unexplored in pancreatic ductal adenocarcinoma (PDAC). The aim of this study was to clarify the role of LY6D in PDAC. We conducted functional analysis of LY6D to evaluate its impact on the malignant features of PDAC cells in vitro. Using our in-house developed stem cell separation technique, which isolates cells with low proteasome activity and CD44 v9 cell surface marker for cancer stem cells, we performed sphere formation and chemosensitivity tests and tumor formation assay in mice, through knockdown of LY6D expression. Immuno-histopathological analysis was also conducted to reveal the clinical significance of LY6D in PDAC. In vitro functional assays demonstrated that LY6D was critically involved in promoting the cancer malignant phenotype, including increased invasive ability, drug resistance, migration capacity, and cancer stemness. Immunohistopathological analysis revealed that high LY6D expression levels were associated with high recurrence rates and poorer prognosis in PDAC. Our study showed that LY6D is a novel prognostic indicator and plays a key role in regulation of cancer stemness in PDAC.

The Role of Heat Shock Factor 1 in Preserving Proteomic Integrity During Copper-Induced Cellular Toxicity

Copper is crucial for many physiological processes across mammalian cells, including energy metabolism, neurotransmitter synthesis, and antioxidant defense mechanisms. However, excessive copper levels can lead to cellular toxicity and “cuproptosis”, a form of programmed cell death characterized by the accumulation of copper within mitochondria. Tumor cells are less sensitive to this toxicity than normal cells, the mechanism for which remains unclear. We address this important issue by exploring the role of heat shock factor 1 (HSF1), a transcription factor that is highly expressed across several types of cancer and has a crucial role in tumor survival, in protecting against copper-mediated cytotoxicity. Using pancreatic ductal adenocarcinoma cells, we show that excessive copper triggers a proteotoxic stress response (PSR), activating HSF1 and that overexpressing HSF1 diminishes intracellular copper accumulation and prevents excessive copper-induced cell death and amyloid fibrils formation, highlighting HSF1′s role in preserving proteasomal integrity. Copper treatment decreases the lipoylation of dihydrolipoamide S-acetyltransferase (DLAT), an enzyme necessary for cuproptosis, induces DLAT oligomerization, and induces insoluble DLAT formation, which is suppressed by overexpressing HSF1, in addition to enhancing the interaction between HSF1 and DLAT. Our findings uncover how HSF1 protects against copper-induced damage in cancer cells and thus represents a novel therapeutic target for enhancing copper-mediated cancer cell death.

CCL3 predicts exceptional response to TGFβ inhibition in basal-like pancreatic cancer enriched in LIF-producing macrophages

The TGFβ receptor inhibitor galunisertib showed promising efficacy in patients with pancreatic ductal adenocarcinoma (PDAC) in the phase 2 H9H-MC-JBAJ study. Identifying biomarkers for this treatment remains essential. Baseline plasma levels of chemokine CCL3 were integrated with clinical outcomes in PDAC patients treated with galunisertib plus gemcitabine (n = 104) or placebo plus gemcitabine (n = 52). High CCL3 was a poor prognostic factor in the placebo group (mOS 3.6 vs. 10.1 months; p < 0.01) but a positive predictor for galunisertib (mOS 9.2 vs. 3.6 months; p < 0.01). Mechanistically, tumor-derived CCL3 activates Tgfβ signaling in macrophages, inducing their M2 phenotype and Lif secretion, sustaining a mesenchymal/basal-like ecotype. TGFβ inhibition redirects macrophage polarization to M1, reducing Lif and shifting PDAC cells to a more epithelial/classical phenotype, improving gemcitabine sensitivity. This study supports exploring TGFβ-targeting agents in PDAC with a mesenchymal/basal-like ecotype driven by high CCL3 levels.

Targeting a chemo-induced adaptive signaling circuit confers therapeutic vulnerabilities in pancreatic cancer

Advanced pancreatic ductal adenocarcinomas (PDACs) respond poorly to all therapies, including the first-line treatment, chemotherapy, the latest immunotherapies, and KRAS-targeting therapies. Despite an enormous effort to improve therapeutic efficacy in late-stage PDAC patients, effective treatment modalities remain an unmet medical challenge. To change the status quo, we explored the key signaling networks underlying the universally poor response of PDAC to therapy. Here, we report a previously unknown chemo-induced symbiotic signaling circuit that adaptively confers chemoresistance in patients and mice with advanced PDAC. By integrating single-cell transcriptomic data from PDAC mouse models and clinical pathological information from PDAC patients, we identified Yap1 in cancer cells and Cox2 in stromal fibroblasts as two key nodes in this signaling circuit. Co-targeting Yap1 in cancer cells and Cox2 in stroma sensitized PDAC to Gemcitabine treatment and dramatically prolonged survival of mice bearing late-stage PDAC, whereas simultaneously inhibiting Yap1 and Cox2 only in cancer cells was ineffective. Mechanistically, chemotherapy triggers non-canonical Yap1 activation by nemo-like kinase in 14-3-3ζ-overexpressing PDAC cells and increases secretion of CXCL2/5, which bind to CXCR2 on fibroblasts to induce Cox2 and PGE2 expression, which reciprocally facilitate PDAC cell survival. Finally, analyses of PDAC patient data revealed that patients who received Statins, which inhibit Yap1 signaling, and Cox2 inhibitors (including Aspirin) while receiving Gemcitabine displayed markedly prolonged survival compared to others. The robust anti-tumor efficacy of Statins and Aspirin, which co-target the chemo-induced adaptive circuit in the tumor cells and stroma, signifies a unique therapeutic strategy for PDAC.

Unveiling the microRNA landscape in pancreatic ductal adenocarcinoma patients and cancer cell models

BackgroundPancreatic ductal adenocarcinoma (PDAC) poses a significant challenge due to late-stage diagnoses resulting from nonspecific early symptoms and the absence of early diagnostic biomarkers. MicroRNAs (miRNAs) play a crucial role in regulating diverse biological processes, and their abnormal expression is observed in various diseases, including cancer. Cancer stem cells (CSCs) are thought to act as a driving force in PDAC spread and recurrence. In pursuing the goal of unravelling the complexities of PDAC and its underlying molecular mechanisms, our study aimed to identify PDAC-associated miRNAs and relate them to disease progression, focusing on their involvement in various PDAC stages in patients and in reliable in vitro models, including pancreatic CSC (PaCSC) models.MethodsThe miRNA profiling datasets of serum and solid biopsies of PDAC patients deposited in GEO DataSets were analyzed by REML-based meta-analysis. The panel was then investigated by Real Time PCR in serum and solid biopsies of 37 PDAC patients enrolled in the study, as well as on BxPC-3 and AsPC-1 PDAC cell lines. We extended our focus towards a possible role of PDAC-associated miRNAs in the CSC phenotype, by inducing CSC-enriched pancreatospheres from BxPC-3 and AsPC-1 PDAC cell lines and performed differential miRNA expression analysis between PaCSCs and monolayer-grown PDAC cell lines.ResultsMeta-analysis showed differentially expressed miRNAs in blood samples and cancerous tissues of PDAC patients, allowing the identification of a panel of 9 PDAC-associated miRNAs. The results emerging from our patients fully confirmed the meta-analysis for the majority of miRNAs under investigation. In vitro tasks confirmed the aberrant expression of the panel of PDAC-associated miRNAs, with a dramatic dysregulation in PaCSC models. Notably, PaCSCs have shown significant overexpression of miR-4486, miR-216a-5p, and miR-216b-5p compared to PDAC cell lines, suggesting the recruitment of such miRNAs in stemness-related molecular mechanisms. Globally, our results showed a dual behaviour of miR-216a-5p and miR-216b-5p in PDAC while miR-4486, miR-361-3p, miR-125a-5p, miR-320d expression changes during the disease suggest they could promote PDAC initiation and progression.ConclusionsThis study contributed to an enhanced comprehension of the role of miRNAs in the development and progression of PDAC, shedding new light on the miRNA landscape in PDAC and its intricate interplay with CSCs, and providing specific insights useful in the development of miRNA-based diagnostic biomarkers and therapeutic targets.

TGF-β-Induced PAUF Plays a Pivotal Role in the Migration and Invasion of Human Pancreatic Ductal Adenocarcinoma Cell Line Panc-1

TGF-β-Induced PAUF Plays a Pivotal Role in the Migration and Invasion of Human Pancreatic Ductal Adenocarcinoma Cell Line Panc-1

Stromal reprogramming overcomes resistance to RAS-MAPK inhibition to improve pancreas cancer responses to cytotoxic and immune therapy.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy that is often resistant to therapy. An immune suppressive tumor microenvironment (TME) and oncogenic mutations in KRAS have both been implicated as drivers of resistance to therapy. Mitogen-activated protein kinase (MAPK) inhibition has not yet shown clinical efficacy, likely because of rapid acquisition of tumor-intrinsic resistance. However, the unique PDAC TME may also be a driver of resistance. We found that long-term focal adhesion kinase (FAK) inhibitor treatment led to hyperactivation of the RAS/MAPK pathway in PDAC cells in mouse models and tissues from patients with PDAC. Concomitant inhibition of both FAK (with VS-4718) and rapidly accelerated fibrosarcoma and MAPK kinase (RAF-MEK) (with avutometinib) induced tumor growth inhibition and increased survival across multiple PDAC mouse models. In the TME, cancer-associated fibroblasts (CAFs) impaired the down-regulation of MYC by RAF-MEK inhibition in PDAC cells, resulting in resistance. By contrast, FAK inhibition reprogramed CAFs to suppress the production of FGF1, which can drive resistance to RAF-MEK inhibition. The addition of chemotherapy to combined FAK and RAF-MEK inhibition led to tumor regression, a decrease in liver metastasis, and improved survival in KRAS-driven PDAC mouse models. Combination of FAK and RAF-MEK inhibition alone improved antitumor immunity and priming of T cell responses in response to chemotherapy. These findings provided the rationale for an ongoing clinical trial evaluating the efficacy of avutometinib and defactinib in combination with gemcitabine and nab-paclitaxel in patients with PDAC and may suggest further paths for combined stromal and tumor-targeting therapies.

KRAS-mediated upregulation of CIP2A promotes suppression of PP2A-B56α to initiate pancreatic cancer development.

Oncogenic mutations in KRAS are present in ~95% of patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) and are considered the initiating event of pancreatic intraepithelial neoplasia (PanIN) precursor lesions. While it is well established that KRAS mutations drive the activation of oncogenic kinase cascades during pancreatic oncogenesis, the effects of oncogenic KRAS signaling on regulation of phosphatases during this process is not fully appreciated. Protein Phosphatase 2A (PP2A) has been implicated in suppressing KRAS-driven cellular transformation and low PP2A activity is observed in PDAC cells compared to non-transformed cells, suggesting that suppression of PP2A activity is an important step in the overall development of PDAC. In the current study, we demonstrate that KRASG12D induces the expression of an endogenous inhibitor of PP2A activity, Cancerous Inhibitor of PP2A (CIP2A), and phosphorylation of the PP2A substrate, c-MYC. Consistent with these findings, KRASG12D sequestered the specific PP2A subunit responsible for c-MYC degradation, B56α, away from the active PP2A holoenzyme in a CIP2A-dependent manner. During PDAC initiation in vivo, knockout of B56α promoted KRASG12D tumorigenesis by accelerating acinar-to-ductal metaplasia (ADM) and the formation of PanIN lesions. The process of ADM was attenuated ex vivo in response to pharmacological re-activation of PP2A utilizing direct small molecule activators of PP2A (SMAPs). Together, our results suggest that suppression of PP2A-B56α through KRAS signaling can promote the MYC-driven initiation of pancreatic tumorigenesis.

Oncogenic GALNT5 confers FOLFIRINOX resistance via activating the MYH9/ NOTCH/ DDR axis in pancreatic ductal adenocarcinoma.

Chemotherapy resistance has been a great challenge in pancreatic ductal adenocarcinoma(PDAC) treatments. Current first-line chemotherapy regimens for PDAC include gemcitabine-based regimens such as AG regimen (albumin paclitaxel and gemcitabine), fluorouracil-based regiments such as FOLFIRINOX regimen ((5-fluorouracil5-FU), oxaliplatin, Irinotecan) and platinum-based regimens for patients with BRCA mutations. large amounts of work have been done on exploring the mechanism underlying resistance of gemcitabine-based and platinum-based regimens, while little research has been achieved on the mechanism of FOLFIRINOX regimens resistance. Hence, we identified Polypeptide N-Acetylgalactosaminyltransferase 5, (GALNT5) as a vital regulator and a potential therapeutic target in FOLFIRINOX regimens resistance. Colony formation assays and flow cytometry assays were performed to explore the roles of GALNT5 in cell proliferation and apoptosis in PDAC treated with FOLFIRINOX. IC50 alterations were calculated in GALNT5 knockdown and overexpressed cell lines. RNA-seq followed by GSEA (gene set enrichment analysis) was displayed to explore the potential mechanism. WB (western blotting), real-time PCR, and IF (immunofluorescence) were performed to validate relative pathways. The mouse orthotopic xenograft PDAC model was established to examine GALNT5 functions in vivo. GALNT5 was highly expressed in PDAC tissues and predicted poor prognosis in PDAC. Upregulation of GALNT5 in PDAC cells conferred FOLFIRINOX resistance on PDAC by inhibiting DNA damage. Moreover, GALNT5 interacted with MYH9, thus participating in the activation of the NOTCH pathways, resulting in hampering FOI-induced DNA damage. Functions of GALNT5 promoting FOLFIRINOX resistance were validated in vivo. In this study, we found that aberrantly overexpressed GALNT5 in PDAC took part in the activation of the NOTCH pathway by interacting with MYH9, thus inhibiting the DDR to achieve FOLFIRINOX resistance and causing poor prognosis. We identified GALNT5 as a potential therapeutic target for PDAC patients resistant to FOLFIRINOX chemotherapy.

NFAT5 governs cellular plasticity-driven resistance to KRAS-targeted therapy in pancreatic cancer.

Resistance to KRAS therapy in pancreatic ductal adenocarcinoma (PDAC) involves cellular plasticity, particularly the epithelial-to-mesenchymal transition (EMT), which poses challenges for effective targeting. Chronic pancreatitis, a known risk factor for PDAC, elevates TGFβ levels in the tumor microenvironment (TME), promoting resistance to KRAS therapy. Mechanistically, TGFβ induces the formation of a novel protein complex composed of SMAD3, SMAD4, and the nuclear factor NFAT5, triggering EMT and resistance by activating key mediators such as S100A4. Inhibiting NFAT5 attenuates pancreatitis-induced resistance to KRAS inhibition and extends mouse survival. Additionally, TGFβ stimulates PDAC cells to secrete CCL2, recruiting macrophages that contribute to KRAS bypass through paracrine S100A4. Our findings elucidate the role of TGFβ signaling in EMT-associated KRAS therapy resistance and identify NFAT5 as a druggable target. Targeting NFAT5 could disrupt this regulatory network, offering a potential avenue for preventing resistance in PDAC.

Semaphorin 3D promotes pancreatic ductal adenocarcinoma progression and metastasis through macrophage reprogramming.

Axon guidance molecules are frequently altered in pancreatic ductal adenocarcinoma (PDA) and influence PDA progression. However, the molecular mechanism remained unclear. Using genetically engineered mouse models to examine semaphorin 3D (SEMA3D), we identified a dual role for tumor- and nerve-derived SEMA3D in the malignant transformation of pancreatic epithelial cells and invasive PDA development. Pancreatic-specific knockout of the SEMA3D gene from the KRASG12D and TP53R172H mutation knock-in, PDX1-Cre(KPC) mouse model demonstrated delayed tumor initiation, prolonged survival, absence of metastasis, and reduced M2 macrophage expression. Mechanistically, tumor- and nerve-derived SEMA3D indirectly reprograms macrophages through KRASMUT-dependent ARF6 signaling in PDA cells, resulting in increased lactate production, which is sensed by GPCR132 on macrophages to stimulate protumorigenic M2 polarization. Multiplex immunohistochemistry demonstrated increased M2-polarized macrophages proximal to nerves in SEMA3D-expressing human PDA tissue. This study suggests that altered SEMA3D expression leads to an acquisition of cancer-promoting functions, and nerve-derived SEMA3D is "hijacked" by PDA cells to support growth and metastasis in a KRASMUT-dependent manner.

SERPINA1 promotes the invasion, metastasis, and proliferation of pancreatic ductal adenocarcinoma via the PI3K/Akt/NF-κB pathway

Serpin peptidase inhibitor clade A member 1 (SERPINA1) is highly expressed in a variety of solid tumors. However, its role in pancreatic ductal adenocarcinoma (PDAC) remains unclear. Here, we report evidence that SERPINA1 acts as a potent oncogene to drive its extremely malignant character. We found that elevated SERPINA1 expression in primary tumors was associated with lymph node metastasis and shorter survival in PDAC patients. Mechanistic investigations revealed that overexpression of SERPINA1 induced nuclear translocation and phosphorylation of the p65 subunit through the PI3K/Akt/NF-κB pathway, thereby promoting the invasion, metastasis and proliferation of PDAC cells in vitro and in vivo. Conversely, the knockdown of SERPINA1 attenuated this signaling pathway and restored the phenotype of PDAC cells overexpressing SERPINA1. Overall, our study reveals that SERPINA1 affects the properties of PDAC through the PI3K/Akt/NF-κB pathway, and its activation confers the clinical features of epithelial-mesenchymal transition and proliferation in the disease.

Suppressing Pancreatic Cancer Survival and Immune Escape via Nanoparticle-Modulated STING/STAT3 Axis Regulation.

Pancreatic ductal adenocarcinoma (PDAC) poses a challenge in oncology due to its high lethality and resistance to immunotherapy. Recently, emerging research on the stimulator of interferon gene (STING) pathway offers novel opportunities for immunotherapy. Although STING expression is retained in PDAC cells, the response of PDAC cells to STING agonists remains ineffective. Signal transducer and activator of transcription 3 (STAT3), a downstream pathway of STING, is notably overexpressed in pancreatic cancer and related to tumor survival and immune escape. We observed that inhibiting STAT3 signaling post-STING activation effectively suppressed tumor growth through signal transducer and activator of transcription 1 (STAT1)-mediated apoptosis but led to a potential risk of immune-related adverse events (irAEs). To address this issue, we designed a tumor-penetrating liposome for the codelivery of STING agonist and STAT3 inhibitor. These nanoparticles regulated the STING/STAT3 signaling axis and effectively inhibited the proliferation and survival of tumor. Simultaneously, we found a significant increase in the activation of NK cells and CD8+ T cells after treatment, leading to robust innate immunity and adaptive immune response. We highlight the potential of regulating the STING/STAT3 axis as a promising treatment for improving clinical outcomes in PDAC patients.

Establishment and Verification of a Novel Gene Signature Connecting Hypoxia and Lactylation for Predicting Prognosis and Immunotherapy of Pancreatic Ductal Adenocarcinoma Patients by Integrating Multi-Machine Learning and Single-Cell Analysis.

Pancreatic ductal adenocarcinoma (PDAC) has earned a notorious reputation as one of the most formidable and deadliest malignant tumors. Within the tumor microenvironment, cancer cells have acquired the capability to maintain incessant expansion and increased proliferation in response to hypoxia via metabolic reconfiguration, leading to elevated levels of lactate within the tumor surroundings. However, there have been limited studies specifically investigating the association between hypoxia and lactic acid metabolism-related lactylation in PDAC. In this study, multiple machine learning approaches, including LASSO regression analysis, XGBoost, and Random Forest, were employed to identify hub genes and construct a prognostic risk signature. The implementation of the CERES score and single-cell analysis was used to discern a prospective therapeutic target for the management of PDAC. CCK8 assay, colony formation assays, transwell, and wound-healing assays were used to explore both the proliferation and migration of PDAC cells affected by CENPA. In conclusion, we discovered two distinct subtypes characterized by their unique hypoxia and lactylation profiles and developed a risk score to evaluate prognosis, as well as response to immunotherapy and chemotherapy, in PDAC patients. Furthermore, we indicated that CENPA may serve as a promising therapeutic target for PDAC.

The long non-coding RNA NEAT1 contributes to aberrant STAT3 signaling in pancreatic cancer and is regulated by a metalloprotease-disintegrin ADAM8/miR-181a-5p axis.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers and several studies demonstrate that STAT3 has critical roles throughout the course of PDAC pathogenesis. TCGA, microarray, and immunohistochemistry data from a PDAC cohort were used for clinical analyses. Panc89 cells with ADAM8 knockout, re-expression of ADAM8 mutants, and Panc1 cells overexpressing ADAM8 were generated. Gene expression analyses of ADAM8, STAT3, long non-coding (lnc) RNA NEAT1, miR-181a-5p and ICAM1 were performed by quantitative PCR. Subcellular fractionation quantified NEAT1 expression in cytoplasm and nucleus of PDAC cell lines. Cell proliferation, scratch, and invasion assays were performed to detect growth rate, migration and invasion capabilities of cells. Gain and loss of function experiments were carried out to investigate the biological effects of lncRNA NEAT1 and miR-181a-5p on PDAC cells and downstream genes. Dual-luciferase reporter gene assay determined interaction and binding sites of miR-181a-5p in lncRNA NEAT1. Pull down assays, RNA binding protein immunoprecipitation (RIP), and ubiquitination assays explored the molecular interaction between lncRNA NEAT1 and STAT3. High ADAM8 expression causes aberrant STAT3 signaling in PDAC cells and is positively correlated with NEAT1 expression. NEAT1 binding to STAT3 was confirmed and prevents STAT3 degradation in the proteasome as increased degradation of STAT3 was observed in ADAM8 knockout cells and cells treated with bortezomib. Furthermore, miRNA-181a-5p regulates NEAT1 expression by direct binding to the NEAT1 promoter. ADAM8 regulates intracellular STAT3 levels via miR-181a-5p and NEAT1 in pancreatic cancer.

Application of LEF-1 immunohistochemical staining in the diagnosis of solid pseudopapillary neoplasm of the pancreas

IntroductionSolid pseudopapillary neoplasm (SPN) is a tumor of young females with gain-of-function mutation in catenin beta 1 gene involved in Wnt signal transduction pathway. Beta-catenin immunohistochemistry (IHC) is used to diagnose SPN. Lymphoid enhancer-binding factor 1 (LEF-1) has been recognized in the transactivation of Wnt pathway. We aim to study LEF-1 IHC in SPN and other pancreatic tumors and compare it with beta-catenin IHC. MethodsWe retrieved cases of SPN, pancreatic neuroendocrine tumor (PanNET), serous cystadenoma (SCA), ductal adenocarcinoma (PDAC) and acinar cell carcinoma (ACC) from 2011 to 2023. Formalin-fixed, paraffin-embedded blocks with adequate tumor were cut and stained with beta-catenin (B-Catenin-1 clone) and LEF-1 (EP310 clone) IHC. Cases were reviewed by two pathologists independently. Nuclear staining with LEF-1 and beta-catenin was considered as positive. ResultsOur cohort consisted of 111 cases [SPN = 59 (42 resections, 11 FNA, 6 biopsies), PDAC = 24, PanNET = 22, SCA = 5, ACC = 1]. For SPN cases male to female ratio was1:8. Age ranged from 9 to 81 years (average: 32 years). Pancreatic tail was the most common location (47 %) followed by head (28 %), body (19 %) and neck (6 %). Tumor size ranged from 1.0 to 12.2 cm (average: 5 cm). Among the SPN cases 57/59 demonstrated strong nuclear LEF-1 staining. 2/49 cases were negative for LEF-1 (both pathologist in agreement). All SPN tumors demonstrated nuclear staining with beta-catenin. Among the non-SPN tumors, beta-catenin showed nuclear staining in 2/52 cases (2 PDAC). The remaining 50 cases were negative for nuclear beta-catenin and demonstrated variable staining pattern with interpretation variability between the two pathologists. The sensitivity and specificity for LEF-1 were 97 % and 100 %, respectively, while for beta-catenin, they were 100 % and 96 % respectively. ConclusionCrisp nuclear staining of LEF-1 without background staining makes diagnostic interpretation relatively easy and accurate compared to beta-catenin IHC. This is further helpful for small biopsy samples to help differentiate SPN from mimickers such as PanNET. None of the non-SPN cases displayed nuclear LEF-1 rendering it a valuable adjunct to beta-catenin in the diagnostic evaluation of SPN.