Adjuvant and neoadjuvant chemotherapy in pancreatic ductal adenocarcinoma

HCST Expression Distinguishes Immune-hot and Immune-cold Subtypes in Pancreatic Ductal Adenocarcinoma

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent malignancy of the pancreas, and the incidence of this disease is approximately equivalent to the mortality rate. Immunotherapy has made a remarkable breakthrough in numerous cancers, while its efficacy in PDAC remains limited due to the immunosuppressive microenvironment. Immunotherapy efficacy is highly correlated with the abundance of immune cells, particularly cytotoxic T cells. Therefore, molecular classifier is needed to identify relatively hot tumors that may benefit from immunotherapy.

Method

In this study, we carried out a transcriptome analysis of 145 pancreatic tumors to define the underlying immune regulatory mechanism driving the PDAC immunosuppressive microenvironment. The immune subtype was identified by consensus clustering, and the underlying PDAC immune activation mechanism was thoroughly examined using single sample gene set enrichment analysis (ssGSEA). Area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to assess the accuracy of the molecular classifier in differentiating immunological subgroups of PDAC.5.

Result

The protein level of molecular classifier was verified by immunohistochemistry in human PDAC tissue. Immune-hot tumors displayed higher levels of immune cell infiltration and immune checkpoint, in line with enriched immune escape pathways. Hematopoietic cell signal transducer (HCST), a molecular classifier used to differentiate immunological subtypes of PDAC, has shown a substantial link with the expression levels of cytotoxic markers, such as CD8A and CD8B. At the single cell level, we found that HCST was predominantly expressed in CD8T cells. By immunohistochemistry and survival analysis, we further demonstrated the prognostic value of HCST in PDAC.

Conclusion

We identified HCST as a molecular classifier to distinguish PDAC immune subtypes, which may be useful for early diagnosis and targeted therapy of PDAC.

PRKRA promotes pancreatic cancer progression by upregulating MMP1 transcription via the NF-κB pathway

Objective

Pancreatic cancer (PC) is highly malignant, but the underlying mechanisms of cancer progression remain unclear. PRKRA is involved in cellular stress response, but its role in PC was unknown.

Methods

The expression of PRKRA between normal and tumor tissues were compared, and the prognostic value of PRKRA was evaluated. SiRNA and plasmids were applied to investigate the effects of PRKRA on PC cells. Organoids and cell lines with knockout and overexpression of PRKRA were established by CRISPR/Cas9 and lentivirus. The effects of PRKRA on PC were evaluated in vivo by cell-derived xenografts. The downstream genes of PRKRA were screened by transcriptome sequencing. The regulation of the target gene was validated by RT-qPCR, western blot, ChIP and dual luciferase reporter assay. Besides, the correlation between PRKRA and gemcitabine sensitivity was investigated by PC organoids.

Results

PRKRA was significantly overexpressed in PC tissues and independently associated with poor prognosis. PRKRA promoted the proliferation, migration, and chemoresistance of PC cells. The proliferation of PC organoids was decreased by PRKRA knockout. The growth and chemoresistance of xenografts were increased by PRKRA overexpression. Mechanistically, PRKRA upregulated the transcription of MMP1 via NF-κB pathway. ChIP and dual luciferase reporter assay showed that NF-κB subunit P65 could bind to the promoter of MMP1. The sensitivity of PC organoids to gemcitabine was negatively correlated with the expression of PRKRA and MMP1.

Conclusions

Our study indicated that the PRKRA/NF-κB/MMP1 axis promoted the progression of PC and may serve as a potential therapeutic target and prognosis marker.

Correlation between hypoxia and HGF/c-MET expression in the management of pancreatic cancer

Pancreatic cancer (PC) is very deadly and difficult to treat. The presence of hypoxia has been shown to increase the probability of cancer developing and spreading. Pancreatic ductal adenocarcinoma (PDAC/PC) has traditionally viewed a highly lethal form of cancer due to its high occurrence of early metastases. Desmoplasia/stroma is often thick and collagenous, with pancreatic stellate cells as the primary source (PSCs). Cancer cells and other stromal cells interact with PSCs, promoting disease development. The hepatocyte growth factor (HGF)/c-MET pathway have been proposed as a growth factor mechanism mediating this interaction. Human growth factor (HGF) is secreted by pancreatic stellate cells (PSCs), and its receptor, c-MET, is generated by pancreatic cancer cells and endothelial cells. Hypoxia is frequent in malignant tumors, particularly pancreatic (PC). Hypoxia results from limitless tumor development and promotes survival, progression, and invasion. Hypoxic is becoming a critical driver and therapeutic target of pancreatic cancer as its hypoxia microenvironment is defined. Recent breakthroughs in cancer biology show that hypoxia promotes tumor proliferation, aggressiveness, and therapeutic resistance. Hypoxia-inducible factors (HIFs) stabilize hypoxia signaling. Hypoxia cMet is a key component of pancreatic tumor microenvironments, which also have a fibrotic response, that hypoxia, promotes and modulates. c-Met is a tyrosine-protein kinase. As describe it simply, the MET gene in humans' codes for a protein called hepatocyte growth factor receptor (HGFR). Most cancerous tumors and pancreatic cancer in particular, suffer from a lack of oxygen (PC). Due to unrestrained tumor development, hypoxia develops, actively contributing to tumor survival, progression, and invasion. As the processes by which hypoxia signaling promotes invasion and metastasis become clear, c-MET has emerged as an important determinant of pancreatic cancer malignancy and a potential pharmacological target. This manuscript provides the most current findings on the role of hypoxia and HGF/c-MET expression in the treatment of pancreatic cancer.

Target c-Myc to treat pancreatic cancer

C-Myc overexpression is a common finding in pancreatic cancer and predicts the aggressive behavior of cancer cells. It binds to the promoter of different genes, thereby regulating their transcription. C-Myc is downstream of KRAS and interacts with several oncogenic and proliferative pathways in pancreatic cancer. C-Myc enhances aerobic glycolysis in cancer cells and regulates glutamate biosynthesis from glutamine. It provides enough energy for cancer cells' metabolism and sufficient substrate for the synthesis of organic molecules. C-Myc overexpression is associated with chemoresistance, intra-tumor angiogenesis, epithelial-mesenchymal transition (EMT), and metastasis in pancreatic cancer. Despite its title, c-Myc is not "undruggable" and recent studies unveiled that it can be targeted, directly or indirectly. Small molecules that accelerate c-Myc ubiquitination and degradation have been effective in preclinical studies. Small molecules that hinder c-Myc-MAX heterodimerization or c-Myc/MAX/DNA complex formation can functionally inhibit c-Myc. In addition, c-Myc can be targeted through transcriptional, post-transcriptional, and translational modifications.

GPR120 promotes metastasis but inhibits tumor growth in pancreatic ductal adenocarcinoma

OBJECTIVES

G-protein-coupled receptor 120 (GPR120) is a long-chain unsaturated fatty acid receptor, which regulates glucose metabolism and lipid. To date, there are disputes on the roles of GPR120 in the pathogenesis of cancer. Besides, little is known about its roles in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC). This study was designed to investigate the roles of GPR120 in the pathogenesis of PDAC.

METHODS

Immunohistochemical staining (IHC) was used for detecting the level of GPR120, epithelial-mesenchymal transformation (EMT) markers, Ki-67 and CD31 in ninety-one PDAC patients. Western blot, CCK8, flow cytometry and transwell assays were performed to determine proliferation, apoptosis, and motility in vitro. Subcutaneous tumor model was established to validate the roles of GPR120 in vivo.

RESULTS

GPR120 was highly expressed in PDAC tissues, which was associated with free fatty acids (FFAs), lymph node metastasis (LNM), and poor prognosis. Moreover, GPR120 activation led to down-regulation of E-cadherin and up-regulation of Snail, Vimentin, N-cadherin, MMP2, MMP9, and CD31. Additionally, GPR120 decreased the expression of P-PI3K, P-AKT and CMYC and increased the level of P-JAK2, P-STAT3, Wnt5a, total β-catenin and β-catenin in nucleus.

CONCLUSIONS

GPR120 promoted proliferation inhibition and apoptosis of PDAC, and contributed to PDAC metastasis via inducing EMT and angiogenesis. GPR120 served as a double-edged sword in the pathogenesis of PDAC.

Comprehensive Analysis of Expression, Prognostic Value, and Immune Infiltration for Ubiquitination-Related FBXOs in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most refractory human malignancies. F-box only proteins (FBXO) are the core components of SKP1-cullin 1-F-box E3 ubiquitin ligase, which have been reported to play crucial roles in tumor initiation and progression via ubiquitination-mediated proteasomal degradation. However, the clinical implications and biological functions of FBXOs in PDAC have not been fully clarified. Herein we perform a comprehensive analysis for the clinical values and functional roles of FBXOs in PDAC using different public databases. We found that FBXO1 (CCNF), FBXO20 (LMO7), FBXO22, FBXO28, FBXO32, and FBXO45 (designated six-FBXOs) were robustly upregulated in PDAC tissues, which predicted an adverse prognosis of PDAC patients. There was a significant correlation between the expression levels of six-FBXOs and the clinicopathological features in PDAC. The transcriptional levels of six-FBXOs were subjected to the influence of promoter methylation levels. There were more than 40% genetic alterations and mutations of six-FBXOs, which affected the clinical outcome of PDAC patients. Furthermore, the expression of six-FBXOs was associated with immune infiltrations and activated status, including B cells, CD8⁺ T cells, CD4⁺ T cells, NK cells, macrophages, and dendritic cells. The functional prediction revealed that the six-FBXOs were involved in ubiquitination-related pathways and other vital signaling pathways, such as p53, PI3K/Akt, and Hippo pathway. Therefore, six-FBXOs are the promising prognostic biomarkers or potential targets for PDAC diagnosis and treatment.

The Fate of Resectable Pancreatic Adenocarcinoma After Neoadjuvant Chemotherapy

OBJECTIVES

Pancreatic cancer continues to be a major cause of cancer-related mortality. There has been a greater implementation of up-front chemotherapy for pancreatic adenocarcinoma patients. Although there are many theoretical benefits to neoadjuvant chemotherapy, its clinical impact is uncertain. We sought to understand the outcomes of patients with resectable and borderline-resectable pancreatic adenocarcinoma who underwent neoadjuvant chemotherapy.

METHODS

Patients were collected in a secure database from September 2018 to May 2020. Patients were excluded if they presented with locally advanced or metastatic disease, inability to complete chemotherapy, or if they were not a surgical candidate.

RESULTS

Sixty-six patients with resectable disease underwent chemotherapy. Folinic acid/5-fluorouracil/irinotecan/oxaliplatin was used in 41 patients (62.1%) and gemcitabine-based regimens in 28 patients (42.4%, greater than 100% as some patients underwent both regimens). After restaging, 47 patients (71.2%) were thought to have resectable disease. Of these patients, 36 have been successfully resected to date. Metastatic disease was found in 12 patients (18.2%) and 6 patients (9.1%) had locally advanced disease.

CONCLUSIONS

Most patients with resectable pancreatic cancer are resected after neoadjuvant chemotherapy, but a subset will develop local or distant progression. Further studies will be needed to determine which patients will progress locally and may benefit from an up-front surgical approach.

Knockdown of LRRN1 inhibits malignant phenotypes through the regulation of HIF-1α/Notch pathway in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most refractory and fatal human malignancies. Leucine-rich repeat neuronal protein-1 (LRRN1) plays a crucial role in the development of the nervous system. However, the clinical implications and biological functions of LRRN1 in PDAC remain unclear. We found that LRRN1 expression was upregulated in PDAC tissues compared with paracancerous tissues and normal pancreatic tissues through the different public databases, tissue microarray-based immunohistochemistry, and dimethylbenzanthracene-induced PDAC murine model. The expression level of LRRN1 was closely related to the overall survival and disease-free survival of PDAC patients. Cox multivariate analysis indicated that LRRN1 was an independent adverse prognostic factor. The small hairpin RNA (shRNA)-mediated LRRN1 knockdown remarkably restrained the proliferative, migratory, and invasive capacities, as well as promoted cell apoptosis and increased G0/G1 arrest in PDAC cells. The xenograft murine subcutaneous bearing model and metastasis model verified that silencing of LRRN1 effectively dampened tumor growth and metastasis in vivo. Specifically, LRRN1 exerted its biological functions through the HIF-1α/Notch signaling pathway, and LRRN1 knockdown could dampen Jagged 1-mediated Notch pathway activation. Therefore, LRRN1 could serve as the potential therapeutic or prognostic target for PDAC.

Upregulated CD58 is associated with clinicopathological characteristics and poor prognosis of patients with pancreatic ductal adenocarcinoma

Background

CD58 has been demonstrated to be abnormally expressed in multiple hematopoietic malignancies and solid tumors and plays an essential role in tumorigenesis and progression; however, its clinical significance and prognostic value in pancreatic ductal adenocarcinoma (PDAC) remain unknown.

Methods

Based on diverse online public databases and 81 PDAC samples of tissue microarray-based immunohistochemistry (IHC), we evaluated CD58 expression in PDAC patients and analyzed its association with clinicopathological characteristics, clinical outcomes, and infiltration of immune cells in PDAC. Furthermore, the correlation between CD58 and the cancer stem cell (CSC)-related, epithelial–mesenchymal transition (EMT)-related, and immune-related markers were detected. Besides, the functional enrichment analysis and related pathways were analyzed and visualized.

Results

CD58 expression was elevated in pancreatitis and PDAC tissues than normal pancreas or adjacent nontumor tissues. The positive cases of CD58 (e.g. more than 50% positive cells) in PDAC account for 95.06% (77/81). Upregulated CD58 in cancer tissues was associated with worse histological grade, larger tumor size, and poorer overall survival and disease-free survival in PDAC patients. Furthermore, Cox multivariate regression analysis revealed that CD58 was an independent prognostic factor in PDAC. CD58 expression was correlated with infiltrations of neutrophils, CD8⁺ T cells, and dendritic cells (DCs). In addition, correlation gene analysis indicated that CD58 expression was strongly correlated with immune-related, EMT-related, and CSC-related markers. Functional enrichment analysis and KEGG pathway manifested that CD58 might be involved in PDAC initiation and progression.

Conclusions

CD58 expression is upregulated in PDAC tissues and its high expression is notably related to poor survival of PDAC. Therefore, CD58 may serve as a novel and effective marker for predicting the prognosis of PDAC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02037-0.

The Role of Mitochondria in the Chemoresistance of Pancreatic Cancer Cells

The first-line chemotherapies for patients with unresectable pancreatic cancer (PC) are 5-fluorouracil (5-FU) and gemcitabine therapy. However, due to chemoresistance the prognosis of patients with PC has not been significantly improved. Mitochondria are essential organelles in eukaryotes that evolved from aerobic bacteria. In recent years, many studies have shown that mitochondria play important roles in tumorigenesis and may act as chemotherapeutic targets in PC. In addition, according to recent studies, mitochondria may play important roles in the chemoresistance of PC by affecting apoptosis, metabolism, mtDNA metabolism, and mitochondrial dynamics. Interfering with some of these factors in mitochondria may improve the sensitivity of PC cells to chemotherapeutic agents, such as gemcitabine, making mitochondria promising targets for overcoming chemoresistance in PC.

Targeting hypoxic tumor microenvironment in pancreatic cancer

Attributable to its late diagnosis, early metastasis, and poor prognosis, pancreatic cancer remains one of the most lethal diseases worldwide. Unlike other solid tumors, pancreatic cancer harbors ample stromal cells and abundant extracellular matrix but lacks vascularization, resulting in persistent and severe hypoxia within the tumor. Hypoxic microenvironment has extensive effects on biological behaviors or malignant phenotypes of pancreatic cancer, including metabolic reprogramming, cancer stemness, invasion and metastasis, and pathological angiogenesis, which synergistically contribute to development and therapeutic resistance of pancreatic cancer. Through various mechanisms including but not confined to maintenance of redox homeostasis, activation of autophagy, epigenetic regulation, and those induced by hypoxia-inducible factors, intratumoral hypoxia drives the above biological processes in pancreatic cancer. Recognizing the pivotal roles of hypoxia in pancreatic cancer progression and therapies, hypoxia-based antitumoral strategies have been continuously developed over the recent years, some of which have been applied in clinical trials to evaluate their efficacy and safety in combinatory therapies for patients with pancreatic cancer. In this review, we discuss the molecular mechanisms underlying hypoxia-induced aggressive and therapeutically resistant phenotypes in both pancreatic cancerous and stromal cells. Additionally, we focus more on innovative therapies targeting the tumor hypoxic microenvironment itself, which hold great potential to overcome the resistance to chemotherapy and radiotherapy and to enhance antitumor efficacy and reduce toxicity to normal tissues.

Up-regulation of CDHR5 expression promotes malignant phenotype of pancreatic ductal adenocarcinoma

CDHR5 has been reported to play key roles in carcinogenesis of various cancers, but its roles in pancreatic cancer have not been reported. The present study was designed to investigate its clinical value in pancreatic ductal adenocarcinoma (PDAC). Tissue microarray-based immunohistochemistry was performed to analyse the correlation between CDHR5 expression and clinical and pathological features of PDAC, as well as the CDHR5 expression during tumour progression. Cell function assays were performed to investigate CDHR5's effects on PDAC cells. Moreover, qRT-PCR was applied to investigate the expression of CDHR5 isoforms in PDAC cells. Expression of CDHR5 was higher on the membrane of PDAC cells. This high expression level was associated with shorter overall survival of PDAC patients and was identified as an independent prognostic factor for overall survival by multivariate Cox regression analysis. In addition, expression level of CDHR5 presented an increased trend in the occurrence and progression of PDAC. Cell experiment suggested that CDHR5 could notably promote invasion and migration of PDAC cells. Moreover, analysis of CDHR5 isoforms indicated CDHR5-L was the major isoform expressed in PDAC cell lines. CDHR5 appears to be a promising and novel prognostic factor for PDAC, and its promotion in PDAC metastasis might be ascribed to the isoform CDHR5-L.