Proliferation Of Pancreatic Cancer Cells Research Articles

Identification of a novel immune checkpoint molecule V-set immunoglobulin domain-containing 4 that leads to impaired immunity infiltration in pancreatic ductal adenocarcinoma

BackgroundCheckpoint-based immunotherapy has failed to elicit responses in the majority of patients with pancreatic cancer. In our study, we aimed to identify the role of a novel immune checkpoint molecule V-set Ig domain-containing 4 (VSIG4) in pancreatic ductal adenocarcinoma (PDAC).MethodsOnline datasets and tissue microarray (TMA) were utilized to analyze the expression level of VSIG4 and its correlation with clinical parameters in PDAC. CCK8, transwell assay and wound healing assay were applied to explore the function of VSIG4 in vitro. Subcutaneous, orthotopic xenograft and liver metastasis model was established to explore the function of VSIG4 in vivo. TMA analysis and chemotaxis assay were conducted to uncover the effect of VSIG4 on immune infiltration. Histone acetyltransferase (HAT) inhibitors and si-RNA were applied to investigate factors that regulate the expression of VSIG4.ResultsBoth mRNA and protein levels of VSIG4 were higher in PDAC than normal pancreas in TCGA, GEO, HPA datasets and our TMA. VSIG4 showed positive correlations with tumor size, T classification and liver metastasis. Patients with higher VSIG4 expression were related to poorer prognosis. VSIG4 knockdown impaired the proliferation and migration ability of pancreatic cancer cells both in vitro and in vivo. Bioinformatics study showed positive correlation between VSIG4 and infiltration of neutrophil and tumor-associated macrophages (TAMs) in PDAC, and it inhibited the secretion of cytokines. According to our TMA panel, high expression of VSIG4 was correlated with fewer infiltration of CD8+ T cells. Chemotaxis assay also showed knockdown of VSIG4 increased the recruitment of total T cells and CD8+ T cells. HAT inhibitors and knockdown of STAT1 led to decreased expression of VSIG4.ConclusionsOur data indicate that VSIG4 contributes to cell proliferation, migration and resistance to immune attack, thus identified as a promising target for PDAC treatment with good prognostic value.

The m6A methyltransferase METTL16 inhibits the proliferation of pancreatic adenocarcinoma cancer cells via the p21 signaling pathway.

Many studies have reported that N6-methyladenosine (m6A) modification plays a critical role in the epigenetic regulation of organisms and especially in the pathogenesis of malignant diseases. However, m6A research has mainly focused on methyltransferase activity mediated by METTL3, and few studies have focused on METTL16. The aim of this study was to investigate the mechanism of METTL16, which mediates m6A modification, and its role in pancreatic adenocarcinoma (PDAC) cell proliferation. Clinicopathologic and survival data were retrospectively collected from 175 PDAC patients from multiple clinical centers to detect the expression of METTL16. CCK-8, cell cycle, EdU and xenograft mouse model experiments were used to evaluate the proliferation effect of METTL16. Potential downstream pathways and mechanisms were explored via RNA sequencing, m6A sequencing, and bioinformatic analyses. Regulatory mechanisms were studied through methyltransferase inhibition, RIP, MeRIP‒qPCR assays. We found that METTL16 expression was markedly downregulated in PDAC, and multivariate Cox regression analyses revealed that METTL16 was a protective factor for PDAC patients. We also demonstrated that METTL16 overexpression inhibited PDAC cell proliferation. Furthermore, we identified a METTL16-p21 signaling axis, with downregulation of METTL16 resulting in inhibition of CDKN1A (p21). Additionally, METTL16 silencing and overexpression experiments highlighted m6A modification alterations in PDAC. METTL16 plays a tumor-suppressive role and suppresses PDAC cell proliferation through the p21 pathway by mediating m6A modification. METTL16 may be a novel marker of PDAC carcinogenesis and target for the treatment of PDAC.

Streamlined DNA-encoded small molecule library screening and validation for the discovery of novel chemotypes targeting BET proteins

Targeting aberrant epigenetic programs that drive tumorigenesis is a promising approach to cancer therapy. DNA-encoded library (DEL) screening is a core platform technology increasingly used to identify drugs that bind to protein targets. Here, we use DEL screening against bromodomain and extra-terminal motif (BET) proteins to identify inhibitors with new chemotypes, and successfully identified BBC1115 as a selective BET inhibitor. While BBC1115 does not structurally resemble OTX-015, a clinically active pan-BET inhibitor, our intensive biological characterization revealed that BBC1115 binds to BET proteins, including BRD4, and suppresses aberrant cell fate programs. Phenotypically, BBC1115-mediated BET inhibition impaired proliferation in acute myeloid leukemia, pancreatic, colorectal, and ovarian cancer cells invitro. Moreover, intravenous administration of BBC1115 inhibited subcutaneous tumor xenograft growth with minimal toxicity and favorable pharmacokinetic properties invivo. Since epigenetic regulations are ubiquitously distributed across normal and malignant cells, it will be critical to evaluate if BBC1115 affects normal cell function. Nonetheless, our study shows integrating DEL-based small-molecule compound screening and multi-step biological validation represents a reliable strategy to discover new chemotypes with selectivity, efficacy, and safety profiles for targeting proteins involved in epigenetic regulation in human malignancies.

LncRNA NORAD regulates the mechanism of the miR-532-3p/Nectin-4 axis in pancreatic cancer cell proliferation and angiogenesis.

Pancreatic cancer (PC) is one of the deadliest cancers worldwide, and cell proliferation and angiogenesis play an important role in its occurrence and development. High levels of lncRNANORAD have been detected in many tumors, including PC, yet the effect and mechanism of lncRNA NORAD on PC cell angiogenesis are unexplored. qRT.PCR was applied to quantify lncRNA NORAD and miR-532-3p expression in PC cells, and a dual luciferase reporter gene was used to verify the targeting effects of NORAD, miR-532-3p and Nectin-4. Then, we regulated NORAD and miR-532-3p expression in PC cells and detected their effects on PC cell proliferation and angiogenesis using cloning experiments and HUVEC tube formation experiments. LncRNA NORAD was upregulated and miR-532-3p was downregulated in PC cells compared with normal cells. Knockdown of NORAD inhibited PC cell proliferation and angiogenesis. LncRNA NORAD and miR-532-3p competitively bound to promote the expression of the miR-532-3p target gene Nectin-4, thereby promoting proliferation and angiogenesis of PC cells in vitro. LncRNA NORAD promotes the proliferation and angiogenesis of PC cells by regulating the miR-532-3p/Nectin-4 axis, which may be a potential biological target in the diagnosis and treatment of clinical PC.

MiR-532-3p inhibited the methylation of SOCS2 to suppress the progression of PC by targeting DNMT3A.

Pancreatic cancer (PC) is one of the deadliest malignancies, with poor diagnosis and prognosis. miR-532-3p has been reported to be a tumor suppressor in various cancers, whereas the mechanism of miR-532-3p in the progression of PC remains poorly understood. In this study, it was found that miR-532-3p and SOCS2 were down-regulated, whereas DNMT3A was up-regulated in PC. Knockdown of DNMT3A or overexpression of miR-532-3p suppressed PC cell proliferation, invasion, and migration, as well as tumor formation in nude mice. DNMT3A induced the methylation of SOCS2 promoter. SOCS2 knockdown reversed the inhibiting effect of DNMT3A silencing on PC cell growth. miR-532-3p directly bound to DNMT3A and negatively regulated its expression while up-regulating SOCS2 levels. DNMT3A overexpression reversed the inhibiting effect of miR-532-3p overexpression on PC cell growth. In conclusion, the overexpression of miR-532-3p could suppress proliferation, invasion, and migration of PC cells, as well as tumor formation in nude mice through inhibiting the methylation of SOCS2 by targeting DNMT3A.

Analysis of cuproptosis-related lncRNA signature for predicting prognosis and tumor immune microenvironment in pancreatic cancer.

Pancreatic cancer (PC) is a highly malignant digestive tract tumor, with a dismal 5-year survival rate. Recently, cuproptosis was found to be copper-dependent cell death. This work aims to establish a cuproptosis-related lncRNA signature which could predict the prognosis of PC patients and help clinical decision-making. Firstly, cuproptosis-related lncRNAs were identified in the TCGA-PAAD database. Next, a cuproptosis-related lncRNA signature based on five lncRNAs was established. Besides, the ICGC cohort and our samples from 30 PC patients served as external validation groups to verify the predictive power of the risk signature. Then, the expression of CASC8 was verified in PC samples, scRNA-seq dataset CRA001160, and PC cell lines. The correlation between CASC8 and cuproptosis-related genes was validated by Real-Time PCR. Additionally, the roles of CASC8 in PC progression and immune microenvironment characterization were explored by loss-of-function assay. As showed in the results, the prognosis of patients with higher risk scores was prominently worse than that with lower risk scores. Real-Time PCR and single cell analysis suggested that CASC8 was highly expressed in pancreatic cancer and related to cuproptosis. Additionally, gene inhibition of CASC8 impacted the proliferation, apoptosis and migration of PC cells. Furthermore, CASC8 was demonstrated to impact the expression of CD274 and several chemokines, and serve as a key indicator in tumor immune microenvironment characterization. In conclusion, the cuproptosis-related lncRNA signature could provide valuable indications for the prognosis of PC patients, and CASC8 was a candidate biomarker for not only predicting the progression of PC patients but also their antitumor immune responses.

USP33 enhances cell survival and stemness by deubiquitinating CTNNB1 in BXPC-3 and SW1990 cells.

Ubiquitin-specific protease 33 (USP33) has been implicated in various cancers, but its biological function and mechanism of action remain unknown in pancreatic cancer (PCa) as a deubiquitinating enzyme. Herein, we report that USP33 silencing inhibits PCa cell survival and self-renewal. USPs highly expressed in spherical PCa cells were screened by comparing the levels of ubiquitin-specific proteases in spherical PCa cells and adherent PCa cells. After silencing USP, the effect of USP on the proliferation of PCa cells was detected by CCK-8 and colony formation assay, and the effect of USP on cell stemness was detected by tumor sphere formation assay, flow analysis, and western blot analysis. The interaction of USP with CTNNB1 and the effect of USP on the ubiquitination of CTNNB1 were verified by coimmunoprecipitation assay. After replenishing CTNNB1, cell proliferation and cell stemness were examined. USP33 is upregulated in spheric BXPC-3, PCNA-1, and SW1990, compared with adherent BXPC-3, PCNA-1, and SW1990. USP33 interacts with CTNNB1, and stabilizes CTNNB1 by suppressing its degradation. Furthermore, cell proliferation, colony-forming, and self-renewal abilities of PCa cells in vitro, and the expression of stem cell markers EpCAM and CD44, C-myc, Nanog, and SOX2, were suppressed when USP33 was knocked down, which was reversed when CTNNB1 was ectopically expressed in PCa cells. Thus, USP33 promotes PCa cell proliferation and self-renewal by inhibiting the degradation of CTNNB1. USP33 inhibition may be a new treatment option for PCa patients.

An ERK1/2‐driven RNA‐binding switch in nucleolin drives ribosome biogenesis and pancreatic tumorigenesis downstream of RAS oncogene

Oncogenic RAS signaling reprograms gene expression through both transcriptional and post‐transcriptional mechanisms. While transcriptional regulation downstream of RAS is relatively well characterized, how RAS post‐transcriptionally modulates gene expression to promote malignancy remains largely unclear. Using quantitative RNA interactome capture analysis, we here reveal that oncogenic RAS signaling reshapes the RNA‐bound proteomic landscape of pancreatic cancer cells, with a network of nuclear proteins centered around nucleolin displaying enhanced RNA‐binding activity. We show that nucleolin is phosphorylated downstream of RAS, which increases its binding to pre‐ribosomal RNA (rRNA), boosts rRNA production, and promotes ribosome biogenesis. This nucleolin‐dependent enhancement of ribosome biogenesis is crucial for RAS‐induced pancreatic cancer cell proliferation and can be targeted therapeutically to inhibit tumor growth. Our results reveal that oncogenic RAS signaling drives ribosome biogenesis by regulating the RNA‐binding activity of nucleolin and highlight a crucial role for this mechanism in RAS‐mediated tumorigenesis.

Targeting SMYD2 inhibits prostate cancer cell growth by regulating c-Myc signaling.

SMYD2 is a lysine histone methyl transferase involved in various cancers epigenetically via methylating histone H3K4, and H3K36. c-Myc is one of the major drivers ofprostate cancer (PCa) initiation and progression. The roles of SMYD2 in PCa and the regulators of c-Myc activity in PCa are still under-researched.SMYD2 expression and survival outcomes in PCa cohorts were analyzed by bioinformatics analysis. SMYD2 protein levels were detected in PCa tissues by immunohistochemistry. SMYD2 knockdown cells were established to identify the effects of SMYD2 on cell growth in vitro and in vivo. GSEA and RNA sequencing were adopted to reconnoiter the signaling regulated by SMYD2 in PCa. The relationship between SMYD2 and c-Myc was examined by western blot analysis, qPCR, and immunohistochemistry. SMYD2 specific inhibitor-AZ505 was used to pharmacologically inhibit SMYD2 function in vitro and in vivo.SMYD2 expression increased in PCa tissues compared with benign prostate tissues and higher SMYD2 expression was associated with a higher risk of biochemical relapse after radical prostatectomy. SMYD2 knockdown inhibited the growth of PCa cells both in vitro and in vivo. Furthermore, high SMYD2 levels conduced to activated c-Myc signaling in PCa cells. Importantly, the pharmacological intervention of SMYD2 by AZ505 significantly repressed PCa cell growth both in vitro and in vivo. Our findings indicate that SMYD2 inhibition restrains PCa cell proliferation by regulating c-Myc signaling and provide evidence for the potential practice of SMYD2 targeting in the treatment of PCa.

Abstract 1729: MG53 suppresses the tumor growth via transcriptional inhibiting the expression of KIF11 in pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer with limited therapeutic options and a dismal long-term survival. The upregulation of KIF11, a motor protein that regulates cell mitosis, has been associated with the aggressive proliferation of pancreatic cancer cells. A molecular strategy to counteract the hyperactivity of KIF11 may represent a potential means to treat PDAC. We previously identified MG53, a member of the tripartite motif family protein (TRIM72), as an important component of tissue repair, and revealed its potential application in regenerative medicine. So far, most published studies have focused on the cytosolic and vesicle-trafficking function of MG53, little is known on the nuclear action of MG53 in pancreatic tumor suppression. In the present study, our confocal imaging revealed frequent appearance of MG53 in the nucleus of human pancreatic cancer cells, and subcellular fractionation assay showed that a majority of MG53 protein was present in the nuclear fraction. Decreased MG53 and increased KIF11 protein expression were observed in both pancreatic cancer cell lines (PANC-1 and mPanc96) and PDAC tissue from surgically resected tumors. Overexpressing MG53 inhibited colony formation and proliferation of PANC-1 cells with significant reduction of KIF11 expression. Furthermore, we demonstrated that MG53-mediated control of KIF11 expression occurs at the gene transcription level. Chromatin immunoprecipitation demonstrated an interaction between MG53 and the promoter of KIF11 in PANC-1 cells. Using a luciferase cell reporter driven by the KIF11 promoter, we found that overexpressing MG53 led to downregulation of the KIF11 transcription activity, and induced cell cycle arrest at the G2/M phase. We also conducted syngeneic orthotopic transplantation of a mouse pancreatic cancer cell line, KPC cells derived from pancreatic tumor in KRasG12D/Trp53-/-/Pdx-1-Cre (KPC) mice, into the pancreas of wild type (WT) and mg53-/- (MG53-KO) mice, which showed aggressive pancreatic tumor growth in MG53-KO mice compared with WT mice after 3-week of transplantation. Western blots revealed that a considerable amount of MG53 protein was found in the pancreatic tumors derived from KPCs in WT mice vs. those in MG53-KO mice, indicating the accumulation of circulating MG53 during tumor growth. Overall, these findings demonstrated that MG53 functions as a tumor suppressor to inhibit cancer cell proliferation and the tumor growth through transcriptional down-regulating the expression of KIF11 in pancreatic cancer, and provided a new therapeutic target for the treatment of patients with PDAC. Citation Format: Xiao-Liang Wang, Xiangfei He, Zobeida Cruz-Monserrate, Allen Tsung, Jianjie Ma, Chuanxi Cai. MG53 suppresses the tumor growth via transcriptional inhibiting the expression of KIF11 in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1729.

Abstract 3932: Targeting cyclin K in pancreatic cancer

Abstract This study focuses on investigating the role of Cyclin K in pancreatic cancer growth and chemotherapeutic sensitivity, aiming to provide pre-clinical evidence for Cyclin K-targeted therapy in pancreatic cancer. Unlike other well-known cyclins, Cyclin K is largely understudied in cancers. Data extracted from the TCGA database indicated that Cyclin K was overexpressed in pancreatic ductal adenocarcinoma (PDAC) and associated with reduced overall survival. Consistently, western blotting showed that Cyclin K was abundantly expressed in human and mouse PDAC cell lines. By using a Tet-On inducible system, we established Cyclin K-depleted and Cyclin K-overexpressed cell lines to evaluate the function of Cyclin K in pancreatic cancer. The proliferation assay showed that Cyclin K depletion led to retarded PDAC cell proliferation, whereas Cyclin K overexpression boosted cell growth. We further confirmed that Cyclin K was required for pancreatic cancer growth in vivo. In addition, cell cycle analysis showed that Cyclin K deficiency resulted in G1-S arrest, while Cyclin K overexpression promoted G1-S progression. By using an RT2 cell cycler array, we identified CDC20 as an important target of Cyclin K that mediated Cyclin K-induced PDAC cell proliferation. To investigate the influence of Cyclin K on chemo-sensitivity, we treated the PDAC cell lines with two newly synthesized Cyclin K molecular glue degraders (HQ461 and NCT02). We found that these degraders specifically ablated Cyclin K and its cognate kinase CDK12 in a very efficient manner. Importantly, we demonstrated that Cyclin K abrogation, either by Cyclin K degrader or Cyclin K knockdown, rendered PDAC cells more sensitive to GemTaxol (gemcitabine plus Taxol) treatment and PARP inhibitors (olaparib or niraparib), as indicated by increased cleavage of PARP or caspase 3. Together, our current results suggest: 1. Cyclin K promotes cell proliferation and G1-S transition in pancreatic cancer; 2. CDC20 mediates the function of Cyclin K on pancreatic cancer cell proliferation; 3. Cyclin K depletion synergizes with GemTaxol or PARP inhibitor in pancreatic cancer treatment. Our study revealed for the first time that Cyclin K plays an essential role in pancreatic cancer growth and chemo-sensitivity, and targeting Cyclin K may offer a great therapeutic avenue for pancreatic cancer patients. Citation Format: Yi Xiao, Jixin Dong, Yuanhong Chen. Targeting cyclin K in pancreatic cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3932.

Paired protein kinases PRKCI-RIPK2 promote pancreatic cancer growth and metastasis via enhancing NF-κB/JNK/ERK phosphorylation

BackgroundProtein kinases play a pivotal role in the malignant evolution of pancreatic cancer (PC) through mediating phosphorylation. Many kinase inhibitors have been developed and translated into clinical use, while the complex pathology of PC confounds their clinical efficacy and warrants the discovery of more effective therapeutic targets.MethodsHere, we used the Gene Expression Omnibus (GEO) database and protein kinase datasets to map the PC-related protein kinase-encoding genes. Then, applying Gene Expression and Profiling Interactive Analysis (GEPIA), GEO and Human Protein Atlas, we evaluated gene correlation, gene expression at protein and mRNA levels, as well as survival significance. In addition, we performed protein kinase RIPK2 knockout and overexpression to observe effects of its expression on PC cell proliferation, migration and invasion in vitro, as well as cell apoptosis, reactive oxygen species (ROS) production and autophagy. We established PC subcutaneous xenograft and liver metastasis models to investigate the effects of RIPK2 knockout on PC growth and metastasis. Co-immunoprecipitation and immunofluorescence were utilized to explore the interaction between protein kinases RIPK2 and PRKCI. Polymerase chain reaction and immunoblotting were used to evaluate gene expression and protein phosphorylation level.ResultsWe found fourteen kinases aberrantly expressed in human PC and nine kinases with prognosis significance. Among them, RIPK2 with both serine/threonine and tyrosine activities were validated to promote PC cells proliferation, migration and invasion. RIPK2 knockout could inhibit subcutaneous tumor growth and liver metastasis of PC. In addition, RIPK2 knockout suppressed autophagosome formation, increased ROS production and PC cell apoptosis. Importantly, another oncogenic kinase PRKCI could interact with RIPK2 to enhance the phosphorylation of downstream NF-κB, JNK and ERK.ConclusionPaired protein kinases PRKCI-RIPK2 with multiple phosphorylation activities represent a new pathological mechanism in PC and could provide potential targets for PC therapy.

Abstract 291: A ketogenic diet rewires pancreatic cancer metabolism towards an actionable metabolic

Abstract Background: A ketogenic regimen is high in fat (90%kCal) and low in carbohydrates (5% kCal), resulting in a state of ketosis[2]. Prior studies suggest that a ketogenic diet shifts carbon utilization in cancer cells from one that is predominantly glycolytic, towards the tricarboxylic acid cycle (TCA) in the mitochondria[3]. The net effect on cancer growth remains uncertain, but the majority of studies in the literature favor an anti-cancer signal. We hypothesize that molecular and biochemical insights into how pancreatic cancer cells adapt to a ketogenic diet will uncover metabolic vulnerabilities and nominate rationally designed therapeutic strategies to effectively partner with the diet. Methods: A ketogenic diet was administered to mice, along with a normal diet in control mice. Pancreatic cancer xenografts were monitored for growth and harvested for biochemical analyses. Tumors were analyzed for metabolites by LC/GC-MS and for oxidative stress by measuring the levels of NAD+/NADH and Lipid Peroxidation assays. Enzyme expression was assessed by Western blot. For in vitro studies, mitochondrial function was analyzed by the Seahorse FX Analyzer and cell growth was measured by PicoGreen DNA quantitation. Result: A ketogenic diet slowed pancreatic cancer growth in multiple in vivo models, including MIA-PaCa2, KPC and patient derived xenografts. TCA metabolites were broadly increased in xenografts exposed to a ketogenic diet. In these mouse tumors, metabolic enzymes associated with the TCA cycle were markedly upregulated, pointing to an effect on gene expression. Specifically, the expression of BDH1 (a ketolytic enzyme allowing ketone body utilization in cancer cells), IDH1 (cytosolic and supports antioxidant defense and mitochondria through NADPH and α-ketoglutarate) and IDH2 (a homolog of IDH1 in the mitochondria) were all increased. In contrast, the glycolytic enzyme, G3P, was reduced. 3). additionally, a ketogenic diet induced oxidative stress in pancreatic cancer in vivo. Based on the adaptations observed in pancreatic cancer, we combined a ketogenic diet with an inhibitor of IDH1 to thwart antioxidant defense and impair mitochondrial function. The combination resulted in markedly reduced tumor proliferation, compared to either treatment alone. In vitro studies revealed that low glucose and fatty acids are likely the major drivers of reduced pancreatic cancer cell proliferation with a ketogenic diet, while exogenous ketone bodies are utilized for energy by mitochondria under glucose withdrawal and generally have a pro-tumor effect. Conclusion: A ketogenic diet has a strong anti-tumor effect in multiple pancreatic cancer mouse models, and the effect is likely a result of the low glucose and increased fatty acid load associated with the diet. Metabolic adaptation towards an OXPHOS phenotype renders pancreatic cancer especially susceptible to antioxidant and mitochondrial inhibitors. Citation Format: Omid Hajihassani, Mehrdad Zarei, Alaxander Loftus, Soubhi Tahan, Peter Gallagher, Kevin Lebo, Helen Chang, Elise Moore, Anusha Mudigonda, Jonathan Hue, Hallie Graor, Jordan Winter. A ketogenic diet rewires pancreatic cancer metabolism towards an actionable metabolic [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 291.

Cuproptosis illustrates tumor micro-environment features and predicts prostate cancer therapeutic sensitivity and prognosis

BackgroundProstate cancer (PCA) is a common malignant genitourinary tumor that significantly impacts patient survival. Cuproptosis, a copper-dependent programmed cell death mechanism, plays a vital role in tumor development, therapy resistance, and immune microenvironment regulation in PCA. However, research on cuproptosis in prostate cancer is still in its early stages. MethodsUsing the publicly available datasets TCGA and GEO, we first acquired the transcriptome and clinical information of PCA patients. The expression of cuprotosis-related genes (CRG) was identified and a prediction model was established based on LASSO-COX method. The predictive performance of this model was evaluated based on Kaplan-Meier method. Using GEO datasets, we further confirmed the critical genes level in the model. Tumor responses to immune checkpoint (ICP) inhibitors were predicted based on Tumor Immune Dysfunction and Exclusion (TIDE) score. The Genomics of Drug Sensitivity in Cancer (GDSC) was utilized to forecast drug sensitivity in cancer cells, whereas the GSVA was employed to analyze enriched pathways related to the cuproptosis signature. Subsequently, the function of PDHA1 gene in PCA was verified. ResultsA predictive risk model on basis of five cuproptosis-related genes (ATP7B, DBT, LIPT1, GCSH, PDHA1) were established. The progression free survival of low-risk group was obviously longer than the high-risk group, and exhibit better response to ICB therapy.Furthermore,PDHA1 is very important in the pathological process of PCA according to regressions analysis result, and the validation of external data sets were conducted. High PDHA1 expression patients with PCA not only had a shorter PFS and were less likely to benefit from ICB treatment, but they were also less responsive to multiple targeted therapeutic drugs. In preliminary research, PDHA1 knockdown significantly decreased the proliferation and invasion of PCA cells. ConclusionThis study established a novel cuproptosis-related gene-based prostate cancer prediction model that accurately predicts the prognosis of PCA patients. The model benefits individualized therapy and can assist clinicians in making clinical decisions for PCA patients. Furthermore, our data show that PDHA1 promotes PCA cell proliferation and invasion while modulating the susceptibility to immunotherapy and other targeted therapies. PDHA1 can be regarded as an important target for PCA therapy.

Viscoelastic hydrogels for interrogating pancreatic cancer-stromal cell interactions.

The tumor microenvironment (TME) is known to direct cancer cell growth, migration, invasion into the matrix and distant tissues, and to confer drug resistance in cancer cells. While multiple aspects of TME have been studied using in vitro, ex vivo, and in vivo tumor models and engineering tools, the influence of matrix viscoelasticity on pancreatic cancer cells and its associated TME remained largely unexplored. In this contribution, we synthesized a new biomimetic hydrogel with tunable matrix stiffness and stress-relaxation for evaluating the effect of matrix viscoelasticity on pancreatic cancer cell (PCC) behaviors in vitro. Using three simple monomers and Reverse-Addition Fragmentation Chain-Transfer (RAFT) polymerization, we synthesized a new class of phenylboronic acid containing polymers (e.g., poly (OEGA-s-HEAA-s-APBA) or PEHA). Norbornene group was conjugated to HEAA on PEHA via carbic anhydride, affording a new NB and BA dually modified polymer - PEHNBA amenable for orthogonal thiol-norbornene photopolymerization and boronate ester diol complexation. The former provided tunable matrix elasticity, while the latter gave rise to matrix stress-relaxation (or viscoelasticity). The new PEHNBA polymers were shown to be highly cytocompatible for in situ encapsulation of PCCs and cancer-associated fibroblasts (CAFs). Furthermore, we demonstrated that hydrogels with high stress-relaxation promoted spreading of CAFs, which in turns promoted PCC proliferation and spreading in the viscoelastic matrix. Compared with elastic matrix, viscoelastic gels upregulated the secretion of soluble proteins known to promote epithelial-mesenchymal transition (EMT). This study demonstrated the crucial influence of matrix viscoelasticity on pancreatic cancer cell fate and provided an engineered viscoelastic matrix for future studies and applications related to TME.

METTL3 enhances pancreatic ductal adenocarcinoma progression and gemcitabine resistance through modifying DDX23 mRNA N6 adenosine methylation

The aim of the present study was to clarify the mechanism of how METTL3 regulated pancreatic ductal adenocarcinoma (PDAC) progression by m6A modification of its downstream target mRNA and signaling pathway. Immunoblotting and qRT-PCR assays was employed to determine the expression levels of METTL3. In situ fluorescence hybridization was conducted to localize the cellular distribution of METTL3 and DEAD-box helicase 23 (DDX23). CCK8, colony formation, EDU incorporation, TUNEL, wound healing and Transwell assays were carried out accordingly to study the viability, proliferation, apoptosis, and mobility of cells under different treatments in vitro. Xenograft and animal lung metastasis experiments were also conducted to study the functional role of METTL3 or DDX23 on tumor growth and lung metastasis in vivo. MeRIP-qPCR and bioinformatical analyses were used to obtain the potential direct targets of METTL3. It was shown that m6A methyltransferase METTL3 was upregulated in PDAC tissues with gemcitabine resistance, and its knockdown sensitized pancreatic cancer cells to chemotherapy. Furthermore, silencing METTL3 remarkably reduced pancreatic cancer cell proliferation, migration, and invasion both in vitro and in vivo. Mechanistically, validation experiments confirmed that DDX23 mRNA was a direct target of METTL3 in YTHDF1-dependent manner. Additionally, DDX23 silence resulted in the suppression of pancreatic cancer cell malignancy and PIAK/Akt signaling inactivation. Strikingly, rescuse experiments demonstrated the inhibitive effects of METTL3 silence on cell phenotypes and gemcitabine resistance were partially reversed by forcibly expressed DDX23. In summary, METTL3 promotes PDAC progression and gemcitabine resistance by modifying DDX23 mRNA m6A methylation and enhancing PI3K/Akt signaling activation. Our findings establish a potential tumor promotive and chemo-resistant role for METTL3/DDX23 axis in PDAC.

The impact of cellular senescence and senescence‑associated secretory phenotype in cancer‑associated fibroblasts on the malignancy of pancreatic cancer.

Cancer‑associated fibroblasts (CAFs) are implicated in the strong malignancy of pancreatic cancer (PC). Various CAF subtypes have different functions, and their heterogeneity likely influence the malignancy of PC. Meanwhile, it is known that senescent cells can create a tumor‑promoting microenvironment by inducing a senescence‑associated secretory phenotype (SASP). In the present study, the effects of individual differences in CAFs on PC malignancy were investigated with a focus on cellular senescence. First, primary cultures of CAFs from 8 PC patients were generated and co‑cultured with PC cell lines. This co‑culture assay showed that differences in CAFs induce differences in PC cell proliferation. It was further investigated which clinical factors affected the malignant potential of CAF and it was found that the difference of malignant potential of each CAF was marginally related to the age of original patients. Next, to verify the senescence of CAFs really affected the malignant potential of CAF, PCR array analysis of each CAF sample was performed and it was revealed that expression of genes about cellular senescence and SASP such as tumor protein p53, nuclear factor kappa B subunit 1, and IL6, are related to the malignant potential of CAFs impacting on PC proliferation. Finally, to elucidate the effect of p53‑mediated cellular senescence of CAFs on malignant potential of PC, it was examined whether CAFs with the treatment of p53 inhibitor affected PC cell proliferation in co‑culture assays. The treatment of CAFs with p53 inhibitor significantly suppressed PC cell proliferation. In addition, a comparison of the concentration of IL‑6, a SASP cytokine, in the co‑culture supernatant showed a significant decrease in the sample after p53 inhibitor treatment. In conclusion, the present results suggested that proliferation potential of PC may be related to p53‑mediated cellular senescence and SASP of CAFs.

LncRNA-NEAT1 inhibits the occurrence and development of pancreatic cancer through spongy miR-146b-5p/traf6

ABSTRACT To investigate the inhibitory effect of LNCNA-NEA1 on pancreatic cancer development and progression via spongiosa miR-146b-5p/TRAF6, 60 pancreatic cancer patients diagnosed from December 2017 to December 2019 were selected as a general source of information. Real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) was used to detect the expression level of NEAT1 in cancerous and adjacent non-cancerous tissues. Cell counting kit-8 (CCK-8) and transwell were used to determine the effect of LNCNA-NEA1 on the proliferation and migration of pancreatic cancer cells (Panc-1). The results of dual luciferase reporter gene assay showed that nea 1 could target and regulate the expression of spongy miR-146b-5p/TRAF6, and reducing the expression of spongy miR-146b-5p/TRAF6 could reverse the inhibitory effects of nea 1-siRNA on proliferation, migration and invasion of pancreatic cancer cells. Therefore, it was concluded that knockdown of nea 1 could inhibit the proliferation, migration and invasion of pancreatic cancer cells by upregulating the level of miR-146b-5p/TRAF6, and the expression of lnc RNA-nea 1 could be used as an indicator for preoperative diagnosis and postoperative prognosis of pancreatic cancer patients.

Identification of ZBTB4 as an immunological biomarker that can inhibit the proliferation and invasion of pancreatic cancer

BackgroundZinc finger and BTB domain-containing protein 4 (ZBTB4) belongs to the zinc finger protein family, which has a role in regulating epigenetic inheritance and is associated with cell differentiation and proliferation. Previous studies have identified aberrant ZBTB4 expression in cancer and its ability to modulate disease progression, but studies on the immune microenvironment, immunotherapy and its role in cancer are still lacking.MethodsHuman pan-cancer and normal tissue transcriptome data were obtained from The Cancer Genome Atlas. The pan-cancer genomic alteration landscape of ZBTB4 was investigated with the online tool. The Kaplan–Meier method was used to evaluate the prognostic significance of ZBTB4 in pancreatic cancer. In parallel, ZBTB4 interacting molecules and potential functions were analyzed by co-expression and the correlation between ZBTB4 and immune cell infiltration, immune modulatory cells and efficacy of immune checkpoint therapy was explored. Next, we retrieved the Gene Expression Omnibus database expression datasets of ZBTB4 and investigated ZBTB4 expression and clinical significance in pancreatic cancer by immunohistochemical staining experiments. Finally, cell experiments were performed to investigate changes in pancreatic cancer cell proliferation, migration and invasion following overexpression and knockdown of ZBTB4.FindingsZBTB4 showed loss of expression in the majority of tumors and possessed the ability to predict cancer prognosis. ZBTB4 was closely related to the tumor immune microenvironment, immune cell infiltration and immunotherapy efficacy. ZBTB4 had good diagnostic performance for pancreatic cancer in the clinic, and ZBTB4 protein expression was lost in pancreatic cancer tumor tissues. Cell experiments revealed that overexpression of ZBTB4 inhibited the proliferation, migration and invasion of pancreatic cancer cells, while silencing ZBTB4 showed the opposite effect.ConclusionsAccording to our results, ZBTB4 is present in pancreatic cancer with aberrant expression and is associated with an altered immune microenvironment. We show that ZBTB4 is a promising marker for cancer immunotherapy and cancer prognosis and has the potential to influence pancreatic cancer progression.

KCNH2 regulates the growth and metastasis of pancreatic cancer

Objective: Due to the characteristics of insidious onset and early metastasis of pancreatic cancer (PC), patients are often diagnosed at an advanced stage and often delayed in completing surgical resection timely, resulting in poor prognosis. Therefore, this study aims to explore the expression of potassium voltage-gated channel subfamily H member 2 (KCNH2) in PC and its relationship with clinicopathological parameters and the related mechanisms. Methods: GEPIA database and immunohistochemical staining were used to analyze the difference in KCNH2 expression between PC and adjacent tissue in RNA and protein levels. Chi-squared test was used to evaluate the relationship between KCNH2 expression and clinicopathological features. The Cox regression model was used for multivariate analysis and univariate analysis. Histological diagnosis was performed according to World Health Organization (WHO) criteria to evaluate the relationship between KCNH2 expression and clinicopathological features. Results: KCNH2 expression was upregulated in PC compared with normal pancreatic tissue. In addition, the knockdown of KCNH2 inhibits PC cell proliferation, migration, invasion, and epithelial-mesenchymal transformation and promotes their apoptosis. In addition, clinical data showed that the abnormal expression of KCNH2 in PC was related to the tumor stage. Patients with high expression of KCNH2 had a poor prognosis. Conclusions: KCNH2 is expected to be a novel targeted molecule in treating PC.