Progress of Exosomes in the Diagnosis and Treatment of Pancreatic Cancer

Calix[6]arene dismantles extracellular vesicle biogenesis and metalloproteinases that support pancreatic cancer hallmarks

Many challenges are faced in pancreatic cancer treatment due to late diagnosis and poor prognosis because of high recurrence and metastasis. Extracellular vesicles (EVs) and matrix metalloproteinases (MMPs), besides acting in intercellular communication, are key players in the cancer cell plasticity responsible for initiating metastasis. Therefore, these entities provide valuable targets for the development of better treatments. In this context, this study aimed to evaluate the potential of calix[6]arene to disturb the release of EVs and the activity of MMPs in pancreatic cancer cells. We found a correlation between the endocytic-associated mediators and the prognosis of pancreatic cancer patients. We observed a more active EV machinery in the pancreatic cancer cell line PANC-1, which was reduced three-fold by treatment with calix[6]arene at subtoxic concentration (5 μM; p 〈0,001). We observed the modulation of 186 microRNAs (164 miRNAs upregulated and 22 miRNAs downregulated) upon calix[6]arene treatment. Interestingly, some of them as miR-4443 and miR-3909, regulates genes HIF1A e KIF13A that are well known to play a role in transport of vesicles. Furthermore, Calix[6]arene downmodulated matrix metalloproteinases (MMPs) -2 and - 9 and disturbed the viability of pancreatic organoids which recapitulate the cellular heterogeneity, structure, and functions of primary tissues. Our findings shed new insights on calix[6]arene's antitumor mechanism, including its intracellular effects on vesicle production and trafficking, as well as MMP activity, which may harm the tumor microenvironment and contribute to a reduction in cancer cell dissemination, which is one of the challenges associated with high mortality in pancreatic cancer.

Exploring the potential of exosomes in diagnosis and drug delivery for pancreatic ductal adenocarcinoma

Pancreatic cancer (PC) is a cancer of the digestive system, and pancreatic ductal adenocarcinoma (PDAC) accounts for approximately 90% of all PC cases. Exosomes derived from PDAC (PDAC-exosomes) promote PDAC development and metastasis. Exosomes are nanoscale vesicles secreted by most cells, which can carry biologically active molecules and mediate communication and cargo transportation among cells. Recent studies have focused on transforming exosomes into good drug delivery systems (DDSs) to improve the clinical treatment of PDAC. This review considers PDAC as the main research object to introduce the role of PDAC-exosomes in PDAC development and metastasis. This review focuses on the following two themes: (a) the great potential of PDAC-exosomes as new diagnostic markers for PDAC, and (b) the transformation of exosomes into potential DDSs.

Crosstalk among long non-coding RNA, tumor-associated macrophages and small extracellular vesicles in tumorigenesis and dissemination

Long noncoding RNAs (lncRNAs), which lack protein-coding ability, can regulate cancer cell growth, proliferation, invasion, and metastasis. Tumor-associated macrophages (TAMs) are key components of the tumor microenvironment that have a significant impact on cancer progression. Small extracellular vesicles (sEV) are crucial mediators of intercellular communications. Cancer cell and macrophage-derived sEV can carry lncRNAs that influence the onset and progression of cancer. Dysregulation of lncRNAs, TAMs, and sEV is widely observed in tumors which makes them valuable targets for cancer immunotherapy. In this review, we summarize current updates on the interactions among sEV, lncRNAs, and TAMs in tumors and provide new perspectives on cancer diagnosis and treatment.

Proteomes of Extracellular Vesicles From Pancreatic Cancer Cells and Cancer-Associated Fibroblasts

OBJECTIVES

Extracellular vesicles (EVs) are lipid bound vesicles secreted by cells into the extracellular environment. Studies have implicated EVs in cell proliferation, epithelial-mesenchymal transition, metastasis, angiogenesis, and mediating the interaction of tumor cells and microenvironment. A systematic characterization of EVs from pancreatic cancer cells and cancer-associated fibroblasts (CAFs) would be valuable for studying the roles of EV proteins in pancreatic tumorigenesis.

METHODS

Proteomic and functional analyses were applied to characterize the proteomes of EVs released from 5 pancreatic cancer lines, 2 CAF cell lines, and a normal pancreatic epithelial cell line (HPDE).

RESULTS

More than 1400 nonredundant proteins were identified in each EV derived from the cell lines. The majority of the proteins identified in the EVs from the cancer cells, CAFs, and HPDE were detected in all 3 groups, highly enriched in the biological processes of vesicle-mediated transport and exocytosis. Protein networks relevant to pancreatic tumorigenesis, including epithelial-mesenchymal transition, complement, and coagulation components, were significantly enriched in the EVs from cancer cells or CAFs.

CONCLUSIONS

These findings support the roles of EVs as a potential mediator in transmitting epithelial-mesenchymal transition signals and complement response in the tumor microenvironment and possibly contributing to coagulation defects related to cancer development.

Improvement of Diagnostic Accuracy for Pancreatic Cancer with Serum Lactate Dehydrogenase

Purpose

Due to the lack of early-stage detection, pancreatic cancer (PC) remains a devastating disease worldwide. Lactate dehydrogenase (LDH) is associated with tumorigenesis and cancer progression. This study aims to analyze the diagnostic improvements in serum LDH levels combined with other common tumor biomarkers, including carbohydrate antigen 19–9 (CA19–9) and carcinoembryonic antigen (CEA), for monitoring PC.

Patients and Methods

A retrospective analysis was performed on 73 patients with newly diagnosed PC, 90 patients with pancreatic benign diseases (PBD), and 92 people with healthy physical examination (HPE) at Zhongda Hospital, Southeast University from July 2013 to July 2020. The diagnostic efficiencies of serum levels of LDH, CA19–9, and CEA were analyzed through receiver operating characteristic (ROC) curves for PC. The sensitivity and specificity were evaluated at an optimal cutoff. The prognostic impacts of LDH on PC patients were also assessed.

Results

The LDH level was elevated in 21 (28.77%) patients with PC, 3 (3.33%) PBD patients, and no HPE individuals (P<0.05). The sensitivities of LDH, CA19–9, and CEA for the diagnosis of PC were 63.0%, 78.1%, and 72.6%, respectively, but the combination of these three markers increased predictive sensitivity significantly to 87.6%. The specificities of LDH, CA19–9, and CEA for the diagnosis of PC were 93.4%, 84.1%, and 73.1%, respectively. The combined specificity reached up to 96.7%. The medium survival time of PC patients with low-level LDH was 21 ± 5.1 months, whereas that of patients with high-level LDH was only 7 ± 0.92 months (P<0.05).

Conclusion

The serum LDH level was higher in PC patients than in PBD patients and HPE individuals and was associated with a poor prognosis. The combined assessment of LDH, CEA, and CA19–9 showed higher sensitivity and specificity for the diagnosis of PC.

Exosomes as new therapeutic vectors for pancreatic cancer treatment

Pancreatic cancer (PC) is one of the deadliest cancers with a very short rate of survival and commonly without symptoms in its early stage. This absence of symptoms can lead to a late diagnosis associated with an advanced metastasis process, for which therapy is not effective. Although with extensive research in this field, the 5-year survival rate has not increased significantly. Notwithstanding, novel insights on risk factors, genetic mutations and molecular mechanisms pave the way for novel therapeutics that urge with a significant part of PC patients presenting resistance to chemotherapy treatments. Exosomes are presented as a promising strategy, working as delivery systems, since they can transport and release their cargoes after fusing with the membrane of pancreatic cells. Exosomes present advantages over liposomes, being less toxic and reaching higher levels in the bloodstream, working as molecule carriers that can inhibit oncogenes, activating tumor suppressor genes and inducing immune responses as well as controlling cell growth. This review intends to provide an overview about the scientific and clinical studies regarding the entire process, from isolation and purification of exosomes, to their design and transformation into anti-oncogenic drug delivering systems, particularly to target PC cells.

The potential roles of exosomes in pancreatic cancer initiation and metastasis

Pancreatic cancer (PaCa) is an insidious and highly metastatic malignancy, with a 5-year survival rate of less than 5%. So far, the pathogenesis and progression mechanisms of PaCa have been poorly characterized. Exosomes correspond to a class of extracellular nanovesicles, produced by a broad range of human somatic and cancerous cells. These particular nanovesicles are mainly composed by proteins, genetic substances and lipids, which mediate signal transduction and material transport. A large number of studies have indicated that exosomes may play decisive roles in the occurrence and metastatic progression of PaCa. This article summarizes the specific functions of exosomes and their underlying molecular mechanisms in mediating the initiation and metastatic capability of PaCa.

Circulating exosomal microRNAs as novel potential detection biomarkers in pancreatic cancer

Circulating exosomal microRNAs (ex-miRNAs) are reflective of the characteristics of the tumor and are valuable biomarkers in different types of tumor. In addition, miRNAs serve important roles in tumor progression and metastasis. The present study aimed to investigate the circulating ex-miRNA-21 and miRNA-210 as novel biomarkers for patients with pancreatic cancer (PC). For this purpose, serum ex-miRNAs were extracted from the serum of patients with PC (n=30) and chronic pancreatitis (CP) (n=10) using an RNA isolation kit. For exosome identification in serum, transmission electron micrographs were used to determine crystalline structure, western blotting was used to identify exosomal markers, and NanoSight was used for nanoparticle characterization. The relative expression levels of ex-miRNAs were quantified using quantitative PCR and compared between patients with PC and CP. The expression levels of both ex-miRNA-21 and miRNA-210 were significantly higher in patients with PC compared with patients with CP (both P<0.001). However, no significant difference in the relative serum levels of free miR-21 and miR-210 was observed between the 2 groups of patients (both P>0.05). ex-miRNA-21 and miRNA-210 were associated with tumor stage, as well as other factors. The diagnostic potential of ex-miRNA-21 and miRNA-210 levels was 83 and 85%, respectively. In addition, when ex-miRNA and serum carbohydrate antigen 19-9 expression levels were combined, the accuracy increased to 90%. The present study identified that serum ex-miRNAs, miRNA-21 and miRNA-210 may be of value as potential biomarkers and therapeutic targets for the diagnosis and treatment of PC.

MicroRNA-124: An emerging therapeutic target in cancer

MicroRNAs (miRNAs) are noncoding single‐stranded RNAs, approximately 20‐24 nucleotides in length, known as powerful posttranscriptional regulators. miRNAs play important regulatory roles in cellular processes by changing messenger RNA expression and are widely involved in human diseases, including tumors. It has been reported in the literature that miRNAs have a precise role in cell proliferation, programmed cell death, differentiation, and expression of coding genes. MicroRNA‐124 (miR‐124) has reduced exparession in various human neoplasms and is believed to be related to the occurrence, development, and prognosis of malignant tumors. In our review, we focus on the specific molecular functions of miR‐124 and the downstream gene targets in major cancers, which provide preclinical evidence for the treatment of human cancer. Although some obstacles exist, miR‐124 is still attracting intensive research focus as a promising and effective anticancer weapon.