Pancreatic Ductal Adenocarcinoma Metastasis Research Articles

Establishment of a nomogram model for predicting distant metastasis in pancreatic ductal adenocarcinoma: a comparative analysis of different lymph node staging systems based on the SEER database

The purpose of this study was to compare the predictive value of different lymph node staging systems and to develop an optimal prognostic nomogram for predicting distant metastasis in pancreatic ductal adenocarcinoma (PDAC). Our study involved 6364 patients selected from the Surveillance, Epidemiology, and End Results (SEER) database and 126 patients from China. Independent risk factors for distant metastasis were screened by univariate and multivariate logistic regression analyses, and a model-based comparison of different lymph node staging systems was conducted. Furthermore, we developed a nomogram for predicting distant metastasis using the optimal performance lymph node staging system. The lymph node ratio (LNR), log odds of positive lymph nodes (LODDS), age, primary site, grade, tumor size, American Joint Committee on Cancer (AJCC) 7th Edition T stage, and radiotherapy recipient status were significant predictors of distant metastasis in PDAC patients. The model with the LODDS was a better fit than the model with the LNR. We developed a nomogram model based on LODDS and six clinical parameters. The area under the curve (AUC) and concordance index (C-index) of 0.753 indicated that this model satisfied the discrimination criteria. Kaplan–Meier curves indicate a significant difference in OS among patients with different metastasis risks. LODDS seems to have a superior ability to predict distant metastasis in PDAC patients compared with the AJCC 8th Edition N stage, PLN and LNR staging systems. Moreover, we developed a nomogram model for predicting distant metastasis. Clinicians can use the model to detect patients at high risk of distant metastasis and to make further clinical decisions.

The lncRNA LINC01605 promotes the progression of pancreatic ductal adenocarcinoma by activating the mTOR signaling pathway

BackgroundThis study investigated the molecular mechanism of long intergenic non-protein coding RNA 1605 (LINC01605) in the process of tumor growth and liver metastasis of pancreatic ductal adenocarcinoma (PDAC).MethodsLINC01605 was filtered out with specificity through TCGA datasets (related to DFS) and our RNA-sequencing data of PDAC tissue samples from Renji Hospital. The expression level and clinical relevance of LINC01605 were then verified in clinical cohorts and samples by immunohistochemical staining assay and survival analysis. Loss- and gain-of-function experiments were performed to estimate the regulatory effects of LINC01605 in vitro. RNA-seq of LINC01605-knockdown PDAC cells and subsequent inhibitor-based cellular function, western blotting, immunofluorescence and rescue experiments were conducted to explore the mechanisms by which LINC01605 regulates the behaviors of PDAC tumor cells. Subcutaneous xenograft models and intrasplenic liver metastasis models were employed to study its role in PDAC tumor growth and liver metastasis in vivo.ResultsLINC01605 expression is upregulated in both PDAC primary tumor and liver metastasis tissues and correlates with poor clinical prognosis. Loss and gain of function experiments in cells demonstrated that LINC01605 promotes the proliferation and migration of PDAC cells in vitro. In subsequent verification experiments, we found that LINC01605 contributes to PDAC progression through cholesterol metabolism regulation in a LIN28B-interacting manner by activating the mTOR signaling pathway. Furthermore, the animal models showed that LINC01605 facilitates the proliferation and metastatic invasion of PDAC cells in vivo.ConclusionsOur results indicate that the upregulated lncRNA LINC01605 promotes PDAC tumor cell proliferation and migration by regulating cholesterol metabolism via activation of the mTOR signaling pathway in a LIN28B-interacting manner. These findings provide new insight into the role of LINC01605 in PDAC tumor growth and liver metastasis as well as its value for clinical approaches as a metabolic therapeutic target in PDAC.

A targetable secreted neural protein drives pancreatic cancer metastatic colonization and HIF1a nuclear retention.

Pancreatic ductal adenocarcinoma (PDAC) is an increasingly diagnosed cancer that kills 90% of afflicted patients, with most patients receiving palliative chemotherapy. We identified neuronal pentraxin 1 (NPTX1) as a cancer secreted protein that becomes over-expressed in human and murine PDAC cells during metastatic progression and identified adhesion molecule with Ig like domain 2 (AMIGO2) as its receptor. Molecular, genetic, biochemical and pharmacologic experiments revealed that secreted NPTX1 acts cell-autonomously on the AMIGO2 receptor to drive PDAC metastatic colonization of the liver-the primary site of PDAC metastasis. NPTX1-AMIGO2 signaling enhanced hypoxic growth and was critically required for hypoxia induced factor-1a (HIF1a) nuclear retention and function. NPTX1 is over-expressed in human PDAC tumors and upregulated in liver metastases. Therapeutic targeting of NPTX1 with a high-affinity monoclonal antibody substantially reduced PDAC liver metastatic colonization. We thus identify NPTX1-AMIGO2 as druggable critical upstream regulators of the HIF1a hypoxic response in PDAC.

Earliest Metabolic Changes Associated with the Initiation of Pancreatic Cancer.

Pancreatic cancer is usually detected at a late stage, when tumors have already metastasized; therefore, it has a poor prognosis with a 5-year survival rate of 11% to 12%. A key to targeting this high mortality is to develop methods for detecting the disease at a stage in which it is still local to the pancreas. However, this needs a better understanding of the events that govern pancreatic cancer oncogenesis. In this issue of Cancer Research, Neuß and colleagues report metabolic changes associated with acinar-to-ductal metaplasia (ADM), an initiating event that leads to the formation of precursor lesions for pancreatic ductal adenocarcinoma (PDAC). Their findings reveal a switch to aerobic glycolysis, increased c-MYC signaling, and increased serine metabolism as driving factors for the ADM process. These findings are important as they demonstrate that metabolic changes that drive the proliferation and metastasis of full-blown PDAC begin in the earliest lesions. The data not only provide insights into how PDAC develops but also a potential explanation for previously described findings, such as circulating lesion cells can be detected even when no carcinoma in situ is present. In summary, this article is highly relevant for furthering our understanding of how metabolic reprogramming drives the earliest events leading to PDAC development and could lay the groundwork for developing methods for early detection or intervention. See related article by Neuß et al., p. 2297.

LINC01133 promotes pancreatic ductal adenocarcinoma epithelial–mesenchymal transition mediated by SPP1 through binding to Arp3

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with limited treatment methods. Long non-coding RNAs (lncRNAs) have been found involved in tumorigenic and progression. The present study revealed that LINC01133, a fewly reported lncRNA, was one of 16 hub genes that could predict PDAC patients’ prognosis. LINC01133 was over-expressed in PDAC tumors compared to adjacent pancreas and could promote PDAC proliferation and metastasis in vitro and in vivo, as well as inhibit PDAC apoptosis. LINC01133 expression positively correlated to secreted phosphoprotein 1 (SPP1) expression, leading to an enhanced epithelial-mesenchymal transition (EMT) process. LINC01133 bound with actin-related protein 3 (Arp3), the complex reduced SPP1 mRNA degradation which increased SPP1 mRNA level, ultimately leading to PDAC proliferation. This research revealed a novel mechanism of PDAC development and provided a potential prognosis indicator that may benefit PDAC patients.

LINC01133 promotes pancreatic ductal adenocarcinoma epithelial–mesenchymal transition mediated by SPP1 through binding to Arp3

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with limited treatment methods. Long non-coding RNAs (lncRNAs) have been found involved in tumorigenic and progression. The present study revealed that LINC01133, a fewly reported lncRNA, was one of 16 hub genes that could predict PDAC patients’ prognosis. LINC01133 was over-expressed in PDAC tumors compared to adjacent pancreas and could promote PDAC proliferation and metastasis in vitro and in vivo, as well as inhibit PDAC apoptosis. LINC01133 expression positively correlated to secreted phosphoprotein 1 (SPP1) expression, leading to an enhanced epithelial-mesenchymal transition (EMT) process. LINC01133 bound with actin-related protein 3 (Arp3), the complex reduced SPP1 mRNA degradation which increased SPP1 mRNA level, ultimately leading to PDAC proliferation. This research revealed a novel mechanism of PDAC development and provided a potential prognosis indicator that may benefit PDAC patients.

HnRNPAB promotes pancreatic ductal adenocarcinoma extravasation and liver metastasis by stablizing MYC mRNA.

Heterogeneous nuclear ribonucleoprotein AB (hnRNPAB) is considered a cancer-promoting heterogeneous nuclear ribonucleoprotein in many cancers, but its function in pancreatic ductal adenocarcinoma (PDAC) is poorly understood. HnRNPAB was highly expressed in PDAC tissues compared to normal pancreatic tissues, and high expression of hnRNPAB was associated with poor overall survival and recurrence-free survival in PDAC patients. HnRNPAB promotes migration and invasion of PDAC cells in vitro. In xenograft tumor mouse models, hnRNPAB deprivation significantly attenuated liver metastasis. HnRNPAB mRNA and protein levels are positively associated with MYC in PDAC cells. Mechanistically, hnRNPAB bound to MYC mRNA and prolonged its half-life of MYC mRNA. HnRNPAB induced PDAC cells to secret CXCL8 via MYC, which promoted neutrophils recruitment and facilitated tumor cells entrancing into the hepatic parenchyma. These findings point to a novel regulatory mechanism via which hnRNPAB promotes PDAC metastasis. Implications: Hnrnpab participates in the post-transcriptional regulation of the oncogene MYC by binding and stabilizing MYC mRNA, thereby promoting liver metastasis in PDAC.

Isoleucyl-tRNA synthetase 2 promotes pancreatic ductal adenocarcinoma proliferation and metastasis by stabilizing β-catenin

Isoleucyl-tRNA synthetase 2 (IARS2), originally regarded as an enzyme ligating isoleucine to the corresponding tRNA, has been identified as an oncogene recently. However, its function in pancreatic ductal adenocarcinoma (PDAC) remains to be discovered. Here we explored the biological role of IARS2 in PDAC. Up-regulated IARS2 was found in PDAC tissues and cell lines. Kaplan–Meier survival analysis indicated a worse prognosis in patients with high IARS2 expression. CCK-8, EdU, and colony formation assays showed IARS2 overexpression enhanced PDAC proliferation, which was reduced by IARS2 knockdown. Meanwhile, IARS2 down-regulation inhibited PDAC metastasis by impeding epithelial–mesenchymal transition. These results were also supported by subcutaneous xenograft and metastasis assays in vivo. To figure out underlying mechanisms, differential and enrichment analyses were conducted and the WNT signaling pathway was discovered. Our results demonstrated that there was no significant relationship between the WNT signaling pathway key factor CTNNB1 and IARS2 at the transcription level. However, cycloheximide assays showed that IARS2 reduced the β-catenin degradation rate. IARS2 inhibited the phosphorylation of β-catenin at the Ser33/37 site and regulated downstream targets of WNT signaling including c-MYC, c-JUN, and MMP7. The enhancement of proliferation and metastasis caused by IARS2 could be reversed by MSAB, an agent that promotes β-catenin degradation. In summary, IARS2 facilitates PDAC proliferation and metastasis by stabilizing β-catenin, which leads to WNT/β-catenin activation. IARS2 serves as an underlying prognosis marker and a potential therapeutic target for PDAC.

MLH1 Inhibits Metastatic Potential of Pancreatic Ductal Adenocarcinoma via Downregulation of GPRC5C

DNA mismatch repair gene MutL homolog-1 (MLH1) has divergent effects in many cancers; however, its impact on the metastasis of pancreatic ductal adenocarcinoma (PDAC) remains unclear. In this study, MLH1 stably overexpressed (OE) and knockdowned (KD) sublines were established. Wound healing and transwell assays were used to evaluate cell migration/invasion. In vivo metastasis was investigated in orthotopic implantation models (severe combined immunodeficiency mice). RT-qPCR and western blotting were adopted to show gene/protein expression. MLH1 downstream genes were screened by transcriptome sequencing. Tissue microarray–based immunohistochemistry was applied to determine protein expression in human specimens. In successfully generated sublines, OE cells presented weaker migration/invasion abilities, compared with controls, whereas in KD cells, these abilities were significantly stronger. The metastasis-inhibitory effect of MLH1 was also observed in mice. Mechanistically, G protein–coupled receptor, family C, group 5, member C (GPRC5C) was a key downstream gene of MLH1 in PDAC cells. Subsequently, transient GPRC5C silencing effectively inhibited cell migration/invasion and remarkably reversed the proinvasive effect of MLH1 knockdown in KD cells. In animal models and human PDAC tissues, tumoral GPRC5C expression, negatively associated with MLH1 expressions, was positively correlated with histologic grade, vessel invasion, and poor cancer-specific survival. In conclusion, MLH1 inhibits the metastatic potential of PDAC via downregulation of GPRC5C.

Stem cell-like circulating tumor cells identified by Pep@MNP and their clinical significance in pancreatic cancer metastasis.

The circulating tumor cells (CTCs) could be captured by the peptide functionalized magnetic nanoparticles (Pep@MNP) detection system in pancreatic ductal adenocarcinoma (PDAC). CTCs and the CXCR4 expression were detected to explore their clinical significance. The CXCR4+ CTCs, this is highly metastatic-prone stem cell-like subsets of CTCs (HM-CTCs), were found to be associated with the early recurrence and metastasis of PDAC. CTCs were captured by Pep@MNP. CTCs were identified via immunofluorescence with CD45, cytokeratin antibodies, and the CXCR4 positive CTCs were assigned to be HM-CTCs. The over-expression of CXCR4 could promote the migration of pancreatic cancer cell in vitro and in vivo. In peripheral blood (PB), CTCs were detected positive in 79.0% of all patients (49/62, 9 (0-71)/2mL), among which 63.3% patients (31/49, 3 (0-23)/2mL) were HM-CTCs positive. In portal vein blood (PVB), CTCs were positive in 77.5% of patients (31/40, 10 (0-40)/2mL), and 67.7% of which (21/31, 4 (0-15)/2mL) were HM-CTCs positive CTCs enumeration could be used as diagnostic biomarker of pancreatic cancer (AUC = 0.862), and the combination of CTCs positive and CA19-9 increase shows improved diagnostic accuracy (AUC = 0.963). in addition, PVB HM-CTCs were more accurate to predict the early recurrence and liver metastasis than PB HM-CTCs (AUC 0.825 vs. 0.787 and 0.827 vs. 0.809, respectively). The CTCs identified by Pep@MNP detection system could be used as diagnostic and prognostic biomarkers of PDAC patients. We identified and defined the CXCR4 over-expressed CTC subpopulation as highly metastatic-prone CTCs, which was proved to identify patients who were prone to suffering from early recurrence and metastasis.

ZKSCAN5 activates LAPTM5 expression by recruiting SETD7 to promote metastasis in pancreatic ductal adenocarcinoma.

Lysosomal-associated transmembrane protein 5 (LAPTM5) has been associated with poor prognosis in cancer patients. Its role in regulating metastasis in pancreatic ductal adenocarcinoma (PDAC), however, remains vague. The study here aimed to expound the metastasis-promoting properties of LAPTM5 in PDAC and the detailed mechanism. LAPTM5 was overexpressed in metastatic PDAC cells and was related to the dismal prognosis of patients in GEO datasets. By using lentiviral vectors harboring short hairpin RNA, we found that LAPTM5 downregulation reduced PDAC cell viability, proliferation, and aggressiveness in vitro and liver metastasis in vivo. Zinc finger with KRAB and SCAN domains 5 (ZKSCAN5) was predicted and verified to mediate LAPTM5 transcription in PDAC cells. Both ZKSCAN5 and SET domains, containing lysine methyltransferase 7 (SETD7) bound to the LAPTM5 promoter, and ZKSCAN5 recruited SETD7 to form a complex promoting LAPTM5 transcription. LAPTM5 knockdown reversed the promoting effect of ZKSCAN5 on the metastasis of PDAC cells. Thus, our findings on the ZKSCAN5/SETD7/LAPTM5 axis provide insights into the underlying mechanism of liver metastasis dissemination in PDAC.

A phase I/II open label study to assess safety and preliminary evidence of a therapeutic effect of azeliragon in patients refractory to first-line treatment of metastatic pancreatic cancer.

TPS4212 Background: Azeliragon is an orally administered small molecule, administered once daily, that inhibits RAGE interactions with its natural ligands, including HMGB1 and S100 proteins. Azeliragon was previously under development for Alzheimer’s disease and failed to show efficacy in phase 3 trials. Clinical safety data from these trials, with over 1500 individuals dosed for periods up to 18 months, indicated that azeliragon has a high level of safety and tolerability, virtually indistinguishable from placebo. RAGE, the receptor for advanced glycation end products, is highly expressed in pancreatic ductal adenocarcinoma (PDAC). RAGE interaction with its ligands, including S100 proteins and HMGB1 released from PDAC cells, promotes PDAC invasion, metastasis, and resistance to 5 FU and Gemcitabine. PDAC-secreted S100 proteins can also stimulate fibroblasts surrounding PDAC cells since RAGE is positively expressed in fibroblasts, promoting the desmoplastic response. RAGE has also been implicated in the muscle wasting associated with cancer and with aging, as well as in neuropathic pain, suggesting a potential supportive role in PDAC treatment. Methods: This is an open label study to determine the safety and preliminary evidence of a therapeutic effect of azeliragon in patients refractory to the standard of care treatment of metastatic pancreatic cancer. Azeliragon is administered at three dose levels in a rolling dose escalation strategy with 6 patients at each dose level: 5 mg/day (level 1), 10 mg/day (level 2) and 20 mg/day (level 3). These dose levels have an initial loading dose for 6 days at 15 mg daily, 15 mg twice a day and 30 mg twice a day, respectively. The primary objective is to determine the RP2D, defined as the dose for which <33% patients experience a dose limiting toxicity (DLT) within 28 days from initiation of dosing. Secondary endpoints include disease control, overall survival, changes in pain as determined by the Brief Pain Inventory, and changes in ECOG performance status, weight, and serum albumin. The study received regulatory approval and accrual started in June 2023. Clinical trial information: NCT05766748 .

FBXO32 Stimulates Protein Synthesis to Drive Pancreatic Cancer Progression and Metastasis.

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related death worldwide, primarily due to its rapid progression. The current treatment options for PDAC are limited, and a better understanding of the underlying mechanisms responsible for PDAC progression is required to identify improved therapeutic strategies. Here, we identified FBXO32 as an oncogenic driver in PDAC. FBXO32 was aberrantly upregulated in PDAC, and high FBXO32 expression was significantly associated with an unfavorable prognosis in PDAC patients. FRG1 deficiency promoted FBXO32 upregulation in PDAC. FBXO32 promoted cell migration and invasion in vitro and tumor growth and metastasis in vivo. Mechanistically, FBXO32 directly interacted with eEF1A1 and promoted its polyubiquitination at the K273 site, leading to enhanced activity of eEF1A1 and increased protein synthesis in PDAC cells. Moreover, FBXO32-catalyzed eEF1A1 ubiquitination boosted the translation of ITGB5 mRNA and activated FAK signaling, thereby facilitating focal adhesion assembly and driving PDAC progression. Importantly, interfering with the FBXO32-eEF1A1 axis or pharmaceutical inhibition of FAK by defactinib, an FDA-approved FAK inhibitor, substantially inhibited PDAC growth and metastasis driven by aberrantly activated FBXO32-eEF1A1 signaling. Overall, this study uncovers a mechanism by which PDAC cells rely on FBXO32-mediated eEF1A1 activation to drive progression and metastasis. FBXO32 may serve as a promising biomarker for selecting eligible PDAC patients for treatment with defactinib.

The scRNA-sequencing landscape of pancreatic ductal adenocarcinoma revealed distinct cell populations associated with tumor initiation and progression

Pancreatic ductal adenocarcinoma (PDAC) stands as a formidable malignancy characterized by its profound lethality. The comprehensive analysis of the transcriptional landscape holds immense significance in understanding PDAC development and exploring novel treatment strategies. However, due to the firm consistency of pancreatic cancer samples, the dissociation of single cells and subsequent sequencing can be challenging. Here, we performed single-cell RNA sequencing (scRNA-seq) on 8 PDAC patients with different lymph node metastasis status. We first identified the crucial role of MMP1 in the transition from normal pancreatic cells to cancer cells. The knockdown of MMP1 in pancreatic cancer cell lines decreased the expression of ductal markers such as SOX9 while the overexpression of MMP1 in hTERT-HPNE increased the expression of ductal markers, suggesting its function of maintaining ductal identity. Secondly, we found a S100A2+ tumor subset which fueled lymph node metastasis in PDAC. The knockdown of S100A2 significantly reduced the motility of pancreatic cancer cell lines in both wound healing and transwell migration assays. While overexpression of S100A2 led to increased migratory capability. Moreover, overexpression of S100A2 in KPC1199, a mouse pancreatic cancer cell line, caused a larger tumor burden in a hemi-spleen injection model of liver metastasis. In addition, epithelial-mesenchymal transition-related genes were decreased by S100A2 knockdown revealed by bulk RNA sequencing. We also identified several pivotal contributors to the pro-tumor microenvironment, notably OMD+ fibroblast and CCL2+ macrophage. As a result, our study provides valuable insights for early detection of PDAC and promising therapeutic targets for combatting lymph node metastasis.

Investigating the influence of taurochenodeoxycholic acid (TCDCA) on pancreatic cancer cell behavior: An RNA sequencing approach

Pancreatic cancer (PC) poses a substantial global health challenge, ranking as the fourth leading cause of cancer-related deaths due to its high mortality rate. Late-stage diagnoses are common due to the absence of specific symptoms. Pancreatic ductal adenocarcinoma (PDAC) accounts for the majority of PC cases. Recent research has suggested a potential link between elevated serum levels of bile acids (BAs) and tumorigenesis of PDAC. This study aims to understand how taurochenodeoxycholic acid (TCDCA), a secondary BA, influences PDAC using RNA sequencing techniques on the Capan-1 cell line. We identified 2,950 differentially expressed genes (DEGs) following TCDCA treatment, with 1,597 upregulated and 1,353 downregulated genes. These DEGs were associated with critical PDAC pathways, including coagulation, angiogenesis, cell migration, and signaling regulation.Furthermore, we reviewed relevant literature highlighting genes like DKK-1, KRT80, UPLA, and SerpinB2, known for their roles in PDAC tumorigenesis and metastasis. Our study sheds light on the complex relationship between BAs and PDAC, offering insights into potential diagnostic markers and therapeutic targets. Further research is needed to unravel these findings' precise mechanisms and clinical implications, potentially improving PDAC diagnosis and treatment.

Systematic analysis of proteome turnover in an organoid model of pancreatic cancer by dSILO

The role of protein turnover in pancreatic ductal adenocarcinoma (PDA) metastasis has not been previously investigated. We introduce dynamic stable-isotope labeling of organoids (dSILO): a dynamic SILAC derivative that combines a pulse of isotopically labeled amino acids with isobaric tandem mass-tag (TMT) labeling to measure proteome-wide protein turnover rates in organoids. We applied it to a PDA model and discovered that metastatic organoids exhibit an accelerated global proteome turnover compared to primary tumor organoids. Globally, most turnover changes are not reflected at the level of protein abundance. Interestingly, the group of proteins that show the highest turnover increase in metastatic PDA compared to tumor is involved in mitochondrial respiration. This indicates that metastatic PDA may adopt alternative respiratory chain functionality that is controlled by the rate at which proteins are turned over. Collectively, our analysis of proteome turnover in PDA organoids offers insights into the mechanisms underlying PDA metastasis.

FAM53B promotes pancreatic ductal adenocarcinoma metastasis by regulating macrophage M2 polarization.

Our study investigated the role of FAM53B in regulating macrophage M2 polarization and its potential mechanisms in promoting pancreatic ductal adenocarcinoma (PDAC) metastasis. To further investigate the role of FAM53B in regulating macrophage M2 polarization and its potential mechanism in promoting PDAC metastasis. Our goal is to determine how FAM53B affects macrophage M2 polarization and to define its underlying mechanism in PDAC metastasis. Cell culture and various experiments, including protein analysis, immunohistochemistry, and animal model experiments, were conducted. We compared FAM53B expression between PDAC tissues and healthy tissues and assessed the correlation of FAM53B expression with clinical features. Our study analyzed the role of FAM53B in macrophage M2 polarization in vitro by examining the expression of relevant markers. Finally, we used a murine model to study the role of FAM53B in PDAC metastasis and analyzed the potential underlying mechanisms. Our research showed that there was a significant increase in FAM53B levels in PDAC tissues, which was linked to adverse tumor features. Experimental findings indicated that FAM53B can enhance macrophage M2 polarization, leading to increased anti-inflammatory factor release. The results from the mouse model further supported the role of FAM53B in PDAC metastasis, as blocking FAM53B prevented tumor cell invasion and metastasis. FAM53B promotes PDAC metastasis by regulating macrophage M2 polarization. This discovery could lead to the development of new strategies for treating PDAC. For example, interfering with the FAM53B signaling pathway may prevent cancer spread. Our research findings also provide important information for expanding our understanding of PDAC pathogenesis.

Nardilysin-regulated scission mechanism activates polo-like kinase 3 to suppress the development of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) develops through step-wise genetic and molecular alterations including Kras mutation and inactivation of various apoptotic pathways. Here, we find that development of apoptotic resistance and metastasis of KrasG12D-driven PDAC in mice is accelerated by deleting Plk3, explaining the often-reduced Plk3 expression in human PDAC. Importantly, a 41-kDa Plk3 (p41Plk3) that contains the entire kinase domain at the N-terminus (1-353 aa) is activated by scission of the precursor p72Plk3 at Arg354 by metalloendopeptidase nardilysin (NRDC), and the resulting p32Plk3 C-terminal Polo-box domain (PBD) is removed by proteasome degradation, preventing the inhibition of p41Plk3 by PBD. We find that p41Plk3 is the activated form of Plk3 that regulates a feed-forward mechanism to promote apoptosis and suppress PDAC and metastasis. p41Plk3 phosphorylates c-Fos on Thr164, which in turn induces expression of Plk3 and pro-apoptotic genes. These findings uncover an NRDC-regulated post-translational mechanism that activates Plk3, establishing a prototypic regulation by scission mechanism.

The nanobody targeting PD-L1 and CXCR4 counteracts pancreatic stellate cell-mediated tumour progression by disrupting tumour microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal malignancy worldwide owing to its complex tumour microenvironment and dense physical barriers. Stromal-derived factor-1 (SDF-1), which is abundantly secreted by tumour stromal cells, plays a pivotal role in promoting PDAC growth and metastasis. In this study, we investigated the impact and molecular mechanisms of the anti-PD-L1&CXCR4 bispecific nanobody on the TME and their consequent interference with PDAC progression. We found that blocking the SDF-1/CXCR4 signalling pathway delayed the epithelial-mesenchymal transition in pancreatic cancer cells. Anti-PD-L1&CXCR4 bispecific nanobody effectively suppress the secretion of SDF-1 by pancreatic stellate cells and downregulate the expression of smooth muscle actin alpha(α-SMA), thereby preventing the activation of cancer-associated fibroblasts by downregulating the PI3K/AKT signaling pathway. This improves the pancreatic tumour microenvironment, favouring the infiltration of T cells into the tumour tissue. In conclusion, our results suggest that the anti-PD-L1&CXCR4 bispecific nanobody exerts an antitumor immune response by changing the pancreatic tumour microenvironment. Hence, the anti-PD-L1&CXCR4 bispecific nanobody is a potential candidate for pancreatic cancer treatment.

NNT-AS1 in CAFs-derived exosomes promotes progression and glucose metabolism through miR-889-3p/HIF-1α in pancreatic adenocarcinoma

It is metabolic and signaling crosstalk between stromal cells and tumors in the tumor microenvironment, which influences several aspects of tumor formation and drug resistance, including metabolic reprogramming. Despite considerable findings linking lncRNAs in HIF-1-related regulatory networks to cancer cell, little emphasis has been given to the role in communication between cancer-associated fibroblasts (CAFs) and tumor cells. Previously, we observed that NNT-AS1 was substantially expressed in CAFs cells and CAFs exosomes, and subsequently investigated the influence of CAFs exosomal NNT-AS1 on glucose metabolism, proliferation, and metastasis of pancreatic ductal adenocarcinoma (PDAC) cells. Transmission electron microscopy was used to examine exosomes secreted by PDAC patient-derived CAFs. qRT-PCR was used to evaluate the expression of NNT-AS1, miR-889-3p, and HIF-1. The role of CAFs-derived exosomal NNT-AS1 in PDAC cell progression and metabolism have been identified. Dual luciferase reporter assays examined the binding between NNT-AS1, miR-889-3p, and HIF-1. After PDAC cells co-culture exosomes secreted by CAFs, we found that they alter glucose metabolism, proliferation, and metastasis. In PDAC cells, CAF-derived exosomal lncRNA NNT-AS1 acted as a molecular sponge for miR-889-3p. Furthermore, HIF-1 could be targeted by miR-889-3p and was controlled by NNT-AS1. This study explores the mechanism by which NNT-AS1 influences the interaction of CAFs on glycolytic remodeling, proliferation, and metastasis of tumor cells through regulating miR-889-3p/HIF-1α, which also helps discover new clinical treatment targets for PDAC.