Evidence for the role of microRNA 374b in acquired cisplatin resistance in pancreatic cancer cells

A dynamic microRNA profile that tracks a chemotherapy resistance phenotype in osteosarcoma. Implications for novel therapeutics

Osteosarcoma is a rare primary bone tumor for which no significant therapeutic advancement has been made since the late 1980s despite ongoing efforts. Overall, the five-year survival rate remains about 65%, and is much lower in patients with tumors unresponsive to methotrexate, doxorubicin, and cisplatin therapy. Genetic studies have not revealed actionable drug targets, but our group, and others, have reported that epigenomic biomarkers, including regulatory RNAs, may be useful prognostic tools for osteosarcoma. We tested if microRNA (miRNA) transcriptional patterns mark the transition from a chemotherapy sensitive to resistant tumor phenotype. Small RNA sequencing was performed using 14 patient matched pre-chemotherapy biopsy and post-chemotherapy resection high-grade osteosarcoma frozen tumor samples. Independently, small RNA sequencing was performed using 14 patient matched biopsy and resection samples from untreated tumors. Separately, miRNA specific Illumina DASL arrays were used to assay an independent cohort of 65 pre-chemotherapy biopsy and 26 patient matched post-chemotherapy resection formalin fixed paraffin embedded (FFPE) tumor samples. mRNA specific Illumina DASL arrays were used to profile 37 pre-chemotherapy biopsy and five post-chemotherapy resection FFPE samples, all of which were also used for Illumina DASL miRNA profiling. The National Cancer Institute Therapeutically Applicable Research to Generate Effective Treatments dataset, including PCR based miRNA profiling and RNA-seq data for 86 and 93 pre-chemotherapy tumor samples, respectively, was also used. Paired differential expression testing revealed a profile of 17 miRNAs with significantly different transcriptional levels following chemotherapy. Genes targeted by the miRNAs were differentially expressed following chemotherapy, suggesting the miRNAs may regulate transcriptional networks. Finally, an in vitro pharmacogenomic screen using miRNAs and their target transcripts predicted response to a set of candidate small molecule therapeutics which potentially reverse the chemotherapy resistance phenotype and synergize with chemotherapy in otherwise treatment resistant tumors. Importantly, these novel therapeutic targets are distinct from targets identified by a similar pharmacogenomic analysis of previously published prognostic miRNA profiles from pre chemotherapy biopsy specimens.

Extracellular Vesicular miRNA in Pancreatic Cancer: From Lab to Therapy

Pancreatic cancer is a prevalent lethal gastrointestinal cancer that generally does not show any symptoms until it reaches advanced stages, resulting in a high mortality rate. People at high risk, such as those with a family history or chronic pancreatitis, do not have a universally accepted screening protocol. Chemotherapy and radiotherapy demonstrate limited effectiveness in the management of pancreatic cancer, emphasizing the urgent need for innovative therapeutic strategies. Recent studies indicated that the complex interaction among pancreatic cancer cells within the dynamic microenvironment, comprising the extracellular matrix, cancer-associated cells, and diverse immune cells, intricately regulates the biological characteristics of the disease. Additionally, mounting evidence suggests that EVs play a crucial role as mediators in intercellular communication by the transportation of different biomolecules, such as miRNA, proteins, DNA, mRNA, and lipids, between heterogeneous cell subpopulations. This communication mediated by EVs significantly impacts multiple aspects of pancreatic cancer pathogenesis, including proliferation, angiogenesis, metastasis, and resistance to therapy. In this review, we delve into the pivotal role of EV-associated miRNAs in the progression, metastasis, and development of drug resistance in pancreatic cancer as well as their therapeutic potential as biomarkers and drug-delivery mechanisms for the management of pancreatic cancer.

Noncoding RNAs: an emerging modulator of drug resistance in pancreatic cancer

Pancreatic cancer is the eighth leading cause of cancer-related deaths worldwide. Chemotherapy including gemcitabine, 5-fluorouracil, adriamycin and cisplatin, immunotherapy with immune checkpoint inhibitors and targeted therapy have been demonstrated to significantly improve prognosis of pancreatic cancer patients with advanced diseases. However, most patients developed drug resistance to these therapeutic agents, which leading to shortened patient survival. The detailed molecular mechanisms contributing to pancreatic cancer drug resistance remain largely unclear. The growing evidences have shown that noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), are involved in pancreatic cancer pathogenesis and development of drug resistance. In the present review, we systematically summarized the new insight on of various miRNAs, lncRNAs and circRNAs on drug resistance of pancreatic cancer. These results demonstrated that targeting the tumor-specific ncRNA may provide novel options for pancreatic cancer treatments.

Small RNA sequencing analysis of peptide-affinity isolated plasma extracellular vesicles distinguishes pancreatic cancer patients from non-affected individuals

Pancreatic ductal adenocarcinoma (PDAC) has a high fatality rate, mainly due to its asymptomatic nature until late-stage disease and therefore delayed diagnosis that leads to a lack of timely treatment intervention. Consequently, there is a significant need for better methods to screen populations that are at high risk of developing PDAC. Such advances would result in earlier diagnosis, more treatment options, and ultimately better outcomes for patients. Several recent studies have applied the concept of liquid biopsy, which is the sampling of a biofluid (such as blood plasma) for the presence of disease biomarkers, to develop screening approaches for PDAC; several of these studies have focused on analysis of extracellular vesicles (EVs) and their cargoes. While these studies have identified many potential biomarkers for PDAC that are present within EVs, their application to clinical practice is hindered by the lack of a robust, reproducible method for EV isolation and analysis that is amenable to a clinical setting. Our previous research has shown that the Vn96 synthetic peptide is indeed a robust and reproducible method for EV isolation that has the potential to be used in a clinical setting. We have therefore chosen to investigate the utility of the Vn96 synthetic peptide for this isolation of EVs from human plasma and the subsequent detection of small RNA biomarkers of PDAC by Next-generation sequencing (NGS) analysis. We find that analysis of small RNA from Vn96-isolated EVs permits the discrimination of PDAC patients from non-affected individuals. Moreover, analyses of all small RNA species, miRNAs, and lncRNA fragments are most effective at segregating PDAC patients from non-affected individuals. Several of the identified small RNA biomarkers have been previously associated with and/or characterized in PDAC, indicating the validity of our findings, whereas other identified small RNA biomarkers may have novel roles in PDAC or cancer in general. Overall, our results provide a basis for a clinically-amendable detection and/or screening strategy for PDAC using a liquid biopsy approach that relies on Vn96-mediated isolation of EVs from plasma.

Expression level of serum miR-347a-5p in patients with acute pancreatitis and its effect on viability, apoptosis, and inflammatory factors of pancreatic acinar cells induced by cerulein

Acute pancreatitis (AP) is one of the life-threatening diseases of the digestive system. MicroRNA has been asserted to be a regulator of AP. This paper explored the miR-374a-5p expression in AP patients and investigated the efficacy of AR42J cells. In this study, 60 healthy people, 58 MAP patients and 58 SAP patients were included, and the serum miR-374a-5p levels of the subjects were detected by RT-qPCR technology. The pancreatitis cell model was structured by stimulating AR42J cells with cerulein. Next, cell viability and apoptosis were detected by CCK-8 assay and flow cytometry. ELISA was used to measure the concentration of cytokines, such as TNF-α, IL-6, and IL-1β. The data showed that miR-374a-5p was downregulated in samples from AP patients, while showing discriminative power for AP populations. Attenuated miR-374a-5p were negatively bound up with patients' Ranson score and APACHE II score. Besides, miR-374a-5p was declined in cerulein-treated AR42J cells and forced elevation of miR-374a-5p was beneficial to increase cell viability, and inhibit cell apoptosis and inflammation. The present study found that miR-374a-5p was reduced in AP serum samples, and up-regulated expression level of miR-374a-5p in cell models had a protective effect on cerulein-induced inhibition of cell function and inflammatory response.

The role of miR-153 and related upstream/downstream pathways in cancers: from a potential biomarker to treatment of tumor resistance and a therapeutic target

MicroRNAs (miRNAs/miRs) are small non-coding RNAs that have a multifunction and play essential roles in gene regulation. Their dysregulation is associated with several human cancers. MiR-153 has a critical role in many biological processes, such as suppressing tumor growth (mostly), responses to treatment, and drug resistance. However, miR-153 in some cancers shows a different role as an oncogene, such as prostate. The miR-153 expression can be regulated by several regulators, such as lncRNAs and circular RNAs. By discovering the target factors for miR-153, it may be possible to approach early diagnosis, reversing drug resistance, and treatment of cancers. This will help choose the precise treatment for the patient and not incur additional costs in treatment. Thus, we attempt to summarize the current situation and potential development prospects about the role of miR-153 in cancers. The miR-153 paly an important role in cancers and can be used for diagnosis and prognosis.

The role of non-coding RNAs in chemotherapy for gastrointestinal cancers

Gastrointestinal (GI) cancers, including colorectal, gastric, hepatic, esophageal, and pancreatic tumors, are responsible for large numbers of deaths around the world. Chemotherapy is the most common approach used to treat advanced GI cancer. However, chemoresistance has emerged as a critical challenge that prevents successful tumor elimination, leading to metastasis and recurrence. Chemoresistance mechanisms are complex, and many factors and pathways are involved. Among these factors, non-coding RNAs (ncRNAs) are critical regulators of GI tumor development and subsequently can induce resistance to chemotherapy. This occurs because ncRNAs can target multiple signaling pathways, affect downstream genes, and modulate proliferation, apoptosis, tumor cell migration, and autophagy. ncRNAs can also induce cancer stem cell features and affect the epithelial-mesenchymal transition. Thus, ncRNAs could possibly act as new targets in chemotherapy combinations to treat GI cancer and to predict treatment response.

MicroRNA-139-5p Suppresses Cell Malignant Behaviors in Breast Cancer through Targeting MEX3A

OBJECTIVE

The study was designed to evaluate the underlying mechanism of microRNA-139-5p in breast cancer (BC).

METHODS

Expression statuses of microRNA-139-5p and MEX3A were measured by qRT-PCR and western blotting. The anticancer effect of microRNA-139-5p in vitro was tested by a set of assays. Interaction between microRNA-139-5p and MEX3A was validated by dual-luciferase detection.

RESULTS

MicroRNA-139-5p expression in BC cells was obviously low, while MEX3A was significantly overexpressed. MicroRNA-139-5p restrained proliferative, invasive, and migratory abilities of BC cells and increased apoptosis level of BC cells, while MEX3A exerted a promoting effect on BC cell growth. Dual-luciferase reporter detection confirmed that microRNA-139-5p bound to MEX3A 3'-UTR.

CONCLUSIONS

MicroRNA-139-5p inhibited the development of BC by targeting MEX3A. MicroRNA-139-5p/MEX3A may be a target for BC therapy.

The Role of microRNA in Pancreatic Cancer

MicroRNAs (miRNAs) are small ribonucleic acid molecules that play a key role in regulating gene expression. The increasing number of studies undertaken on the functioning of microRNAs in the tumor formation clearly indicates their important potential in oncological therapy. Pancreatic cancer is one of the deadliest cancers. The expression of miRNAs released into the bloodstream appears to be a good indicator of progression and evaluation of the aggressiveness of pancreatic cancer, as indicated by studies. The work reviewed the latest literature on the importance of miRNAs for pancreatic cancer development.

miRNome and Functional Network Analysis of PGRMC1 Regulated miRNA Target Genes Identify Pathways and Biological Functions Associated With Triple Negative Breast Cancer

Background

Increased expression of the progesterone receptor membrane component 1, a heme and progesterone binding protein, is frequently found in triple negative breast cancer tissue. The basis for the expression of PGRMC1 and its regulation on cellular signaling mechanisms remain largely unknown. Therefore, we aim to study microRNAs that target selective genes and mechanisms that are regulated by PGRMC1 in TNBCs.

Methods

To identify altered miRNAs, whole human miRNome profiling was performed following AG-205 treatment and PGRMC1 silencing. Network analysis identified miRNA target genes while KEGG, REACTOME and Gene ontology were used to explore altered signaling pathways, biological processes, and molecular functions.

Results

KEGG term pathway analysis revealed that upregulated miRNAs target specific genes that are involved in signaling pathways that play a major role in carcinogenesis. While multiple downregulated miRNAs are known oncogenes and have been previously demonstrated to be overexpressed in a variety of cancers. Overlapping miRNA target genes associated with KEGG term pathways were identified and overexpression/amplification of these genes was observed in invasive breast carcinoma tissue from TCGA. Further, the top two genes (CCND1 and YWHAZ) which are highly genetically altered are also associated with poorer overall survival.

Conclusions

Thus, our data demonstrates that therapeutic targeting of PGRMC1 in aggressive breast cancers leads to the activation of miRNAs that target overexpressed genes and deactivation of miRNAs that have oncogenic potential.

Noncoding RNAs Associated with Therapeutic Resistance in Pancreatic Cancer

Therapeutic resistance is an inevitable impediment towards effective cancer therapies. Evidence accumulated has shown that the signaling pathways and related factors are fundamentally responsible for therapeutic resistance via regulating diverse cellular events, such as epithelial-to-mesenchymal transition (EMT), stemness, cell survival/apoptosis, autophagy, etcetera. Noncoding RNAs (ncRNAs) have been identified as essential cellular components in gene regulation. The expression of ncRNAs is altered in cancer, and dysregulated ncRNAs participate in gene regulatory networks in pathological contexts. An in-depth understanding of molecular mechanisms underlying the modulation of therapeutic resistance is required to refine therapeutic benefits. This review presents an overview of the recent evidence concerning the role of human ncRNAs in therapeutic resistance, together with the feasibility of ncRNAs as therapeutic targets in pancreatic cancer.

Valproic acid combined with cisplatin-based chemoradiation in locally advanced head and neck squamous cell carcinoma patients and associated biomarkers

Background

Cisplatin-based chemoradiation (CCRT) offers locally advanced head and neck squamous cell carcinoma (LAHNSCC) patients high local control rate, however, relapses are frequent. Our goal was to evaluate if association of valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, with CCRT improved response rate (RR) and associated biomarkers.

Methods

This phase II trial included patients with unresectable locally advanced (LA) oropharynx (OP) squamous cell carcinoma. CCRT began after 2 weeks of VPA (P1). Primary goal was RR at 8 weeks after chemoradiation (CRT)+VPA (P2). Biomarkers included microRNA (miR) polymerase chain reaction (PCR)-array profiling in plasma compared to healthy controls by two-sample t-test. Distribution of p-values was analysed by beta-uniform mixture. Findings were validated by real-time PCR quantitative polymerase chain reaction (qPCR) for selected miRs in plasma and saliva. p16, HDAC2 and RAD23 Homolog B, Nucleotide Excision Repair Protein (HR23B) tumour immunohistochemistry were evaluated.

Results

Given significant toxicities, accrual was interrupted after inclusion of ten LA p16 negative OP patients. All were male, smokers/ex-smokers, aged 41–65 and with previous moderate/high alcohol intake. Nine evaluable patients yielded a RR of 88%. At false discovery rate of 5%, 169 miRs were differentially expressed between patients and controls, including lower expression of tumour suppressors (TSs) such as miR-31, -222, -let-7a/b/e and -145. miR-let-7a/e expression was validated by qPCR using saliva. A HDAC2 H-score above 170 was 90% accurate in predicting 6-month disease-free survival.

Conclusions

VPA and CRT offered high RR; however, with prohibitive toxicities, which led to early trial termination. Patients and controls had a distinct pattern of miR expression, mainly with low levels of TS miRs targeting Tumor protein P53 (TP53). miR-let-7a/e levels were lower in patients compared to controls, which reinforces the aggressive nature of such tumours (NCT01695122).

Functional roles of exosomal miRNAs in multi-drug resistance in cancer chemotherapeutics

Recent understanding of different molecular aspects of tumor initiation and progression has led to the discovery of a growing list of drugs. While these drugs have shown promising effects on tumor cells, their widespread usage has been hampered by the acquisition of drug resistance in a subpopulation of tumor cells. A differential pattern in the secretion of specialized vesicles named "exosomes" in drug-resistant cancer cells have recently received much attention. In addition, microRNAs (miRNAs) have been shown to be enriched in exosomes. Exosomal miRNAs (also known as exo-miRs) could be shuttled to recipient cells and play a role in the regulation of post-transcriptional gene expression, which may exert certain effects on cancer drug resistance. Here, we have reviewed the role of exo-miRs in chemotherapeutic resistance in different cancer types. Besides, studies which have focused on predictive role of circulating exo-miRs in cancer drug resistance are reviewed.

Noncoding RNAs in drug-resistant pancreatic cancer: A review

Pancreatic cancer is the fourth-leading cause of cancer-related deaths and is expected to be the second-leading cause of cancer-related deaths in Europe and the United States by 2030. The high fatality rate of pancreatic cancer is ascribed to untimely diagnosis, early metastasis and limited responses to both chemotherapy and radiotherapy. Although gemcitabine, 5-fluorouracil and some other drugs can profoundly improve patient prognosis, most pancreatic cancer patients eventually develop drug resistance, leading to poor clinical outcomes. The underlying mechanisms of pancreatic cancer drug resistance are complicated and inconclusive. Interestingly, accumulating evidence has demonstrated that different noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play a crucial role in pancreatic cancer resistance to chemotherapy reagents. In this paper, we systematically summarize the molecular mechanism underlying the influence of ncRNAs on the generation and development of drug resistance in pancreatic cancer and discuss the potential role of ncRNAs as prognostic markers and new therapeutic targets for pancreatic cancer.

MicroRNA-374b mediates the initiation of non-small cell lung cancer by regulating ITGB1 and p53 expressions

Background

Previous studies have shown that microRNAs (miRNAs) play important roles in the pathogenesis of human cancers. This study aims to clarify the role of miR‐374b in non‐small cell lung cancer (NSCLC).

Methods

In this study, RT‐qPCR and western blot analysis were used to measure mRNA and protein expression. The regulatory mechanism of miR‐374b/ITGB1 was investigated by dual‐luciferase reporter, CCK‐8, and transwell assays.

Results

MiR‐374b expression was reduced in NSCLC tissues and associated with lymph node metastasis, tumor stage and prognosis in NSCLC patients. Functionally, overexpression of miR‐374b inhibited cell viability and metastasis in NSCLC. In addition, miR‐374b blocked EMT and promoted p53 expression in NSCLC. MiR‐374b was found to directly target ITGB1. Furthermore, upregulation of ITGB1 weakened the antitumor effect of miR‐374b in NSCLC.

Conclusions

MiR‐374b inhibits the tumorigenesis of NSCLC by downregulating ITGB1 and upregulating p53.

The ability of miRNAs to induce mesenchymal-to-epithelial transition (MET) in cancer cells is highly dependent upon genetic background

Understanding of the molecular basis of host cell-miRNA interactions is prerequisite to the successful application of miRNAs as potential therapeutic agents. We studied the morphological and molecular consequences of over expression of three sequence divergent miRNAs previously implicated in the mesenchymal-to-epithelial transition process (MET) in three distinct mesenchymal-like cancer cell lines. The ability of miRNAs to induce morphological changes characteristic of MET positively correlated with induced changes in the expression of genes previously implicated in the process. Variability in the responses of different mesenchymal-like cells to over expression of the same miRNAs was attributable to inherent differences in trans-regulatory profiles pre-disposing these cells to miRNA-induced MET. Collectively our results indicate that miRNA-mediated regulation of MET is a highly integrated process that is significantly modulated by the molecular background of individual cells.

Effect of miR-26b-5p on cis-diamine dichloroplatinum-induced ovarian granulosa cell injury by targeting MAP3K9

The proliferation and differentiation of granulosa cells are very important for follicular development. The dysfunction of granulosa cells leading to follicular development is an important cause of ovarian endocrine abnormalities. More and more evidence shows that microRNAs are involved in the regulation of ovarian granulosa cell function. It has been found that MiR-26b may be involved in CDDP resistance. Studies have shown that miR-26b can promote apoptosis of ovarian granulosa cells, but there are few studies on its mechanism, and no studies have been found on the damage of miR-26b-5p to rat ovarian granulosa cells induced by CDDP. Identification of ovarian granulosa cells was conducted by immunochemical staining. Cell counting kit 8 (CCK-8) was used to detect cell viability, flow cytometry was used to detect cell apoptosis, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot (WB) were used to analyze the expression of miR-26b-5p, MAP3K9, cleaved Caspase-3, Bax, and Bcl-2; dual-luciferase reporter assay results further verify the targeting relation between miR-26b-5p and MAP3K9. CDDP remarkably inhibited ovarian granulosa cell viability and induced ovarian granulosa cell apoptosis; miR-26b-5p inhibitor enhanced viability and inhibited apoptosis of ovarian granulosa cells, which treated with CDDP, but had little effect on normal cells. MAP3K9 partially reversed the effect of miR-26b-5p on ovarian granulosa cells induced by CDDP. miR-26b-5p has a protective effect on CDDP-induced ovarian granulosa cells via targeting MAP3K9.

Long Non-Coding RNA MAGI2-AS3 is a New Player with a Tumor Suppressive Role in High Grade Serous Ovarian Carcinoma

High-Grade Serous Ovarian Carcinoma (HGSC) is the most incidental and lethal subtype of epithelial ovarian cancer (EOC) with a high mortality rate of nearly 65%. Recent findings aimed at understanding the pathogenesis of HGSC have attributed its principal source as the Fallopian Tube (FT). To further comprehend the exact mechanism of carcinogenesis, which is still less known, we performed a transcriptome analysis comparing FT and HGSC. Our study aims at exploring new players involved in the development of HGSC from FT, along with their signaling network, and we chose to focus on non-coding RNAs. Non-coding RNAs (ncRNAs) are increasingly observed to be the major regulators of several cellular processes and could have key functions as biological markers, as well as even a therapeutic approach. The most physiologically relevant and significantly dysregulated non-coding RNAs were identified bioinformatically. After analyzing the trend in HGSC and other cancers, MAGI2-AS3 was observed to be an important player in EOC. We assessed its tumor-suppressive role in EOC by means of various assays. Further, we mapped its signaling pathway using its role as a miRNA sponge to predict the miRNAs binding to MAGI2AS3 and showed it experimentally. We conclude that MAGI2-AS3 acts as a tumor suppressor in EOC, specifically in HGSC by sponging miR-15-5p, miR-374a-5p and miR-374b-5p, and altering downstream signaling of certain mRNAs through a ceRNA network.

Bioinformatics analysis of circulating miRNAs related to cancer following spinal cord injury

Patients with spinal cord injury (SCI) have an increased risk of developing esophageal, bladder and hematologic malignancies compared with the normal population. In the present study, we aimed to identify, through in silico analysis, miRNAs and their target genes related to the three most frequent types of cancer in individuals with SCI. In a previous study, we reported a pattern of expression of miRNAs in 17 sedentary SCI males compared with 22 healthy able-bodied males by TaqMan OpenArray. This list of miRNAs deregulated in SCI patients was uploaded to miRWALK2.0 to predict the target genes and pathways of selected miRNAs. We used Cytoscape software to construct the network displaying the miRNAs and their gene targets. Among the down-regulated miRNAs in SCI, 21, 19 and 20 miRNAs were potentially associated with hematological, bladder and esophageal cancer, respectively, and three target genes (TP53, CCND1 and KRAS) were common to all three types of cancer. The three up-regulated miRNAs were potentially targeted by 18, 15 and 10 genes associated with all three types of cancer. Our current bioinformatics analysis suggests the potential influence of several miRNAs on the development of cancer in SCI. In general, these data may provide novel information regarding potential molecular mechanisms involved in the development of cancer among individuals with SCI. Further studies aiming at understanding how miRNAs contribute to the development of the major cancers that affect patients after SCI may help elucidate the role of these molecules in the pathophysiology of the disease.

Electropermeabilization of metastatic chondrosarcoma cells from primary cell culture

Primary cell cultures are challenging, but reliable model reflecting tumor response in vitro. The study was designed to examine if the increased electropermeabilization can overcame initial drug insensitivity in chondrosarcoma cells from lung metastasis. We established a primary cell culture and evaluated the cytotoxic impact of four drugs-cisplatin (CDDP), camptothecin, 2-methoxyestradiol, and leucovorin calcium (LeuCa). After determination of parameters allowing for electropermeabilization, we performed electrochemotherapy in vitro with the least toxic drugs-CDDP and LeuCa. Although combining CDDP and leucovorin together increased their toxicity and supported apoptosis, application of pulsed electric fields (PEFs) brought no advantage for their efficacy. The study emphasizes the need for introduction of primary cell cultures into studies on pulse electric fields as model frequently less sensitive to PEF-based treatments than continuous cell lines.

miR-374a-5p: A New Target for Diagnosis and Drug Resistance Therapy in Gastric Cancer

Chemoresistance is one of the causes associated with poor prognosis in gastric cancer. MicroRNAs (miRNAs) are important regulators of chemoresistance. Exosome-mediated delivery of anti-cancer molecules and drugs have emerged as a new approach for cancer therapy. We first examined the expression of miR-374a-5p in gastric cancer serum by qRT-PCR and explored the clinicopathological parameters. We then performed in vitro cell and molecular studies, including CCK-8 assay, flow cytometry, qRT-PCR, and western blot, to determine the roles of miR-374a-5p in gastric cancer chemoresistance and identified its downstream target by luciferase reporter assay. We also used in vivo animal studies to evaluate the therapeutic efficacy of miR-374a-5p inhibitor and exosome-mediated delivery of miR-374a-5p inhibitor in gastric cancer. miR-374a-5p expression level was elevated in gastric cancer serum, and its upregulation predicted poor prognosis. miR-374a-5p overexpression promoted while miR-374a-5p knockdown inhibited gastric cancer chemoresistance in vitro and in vivo. miR-374a-5p bound to Neurod1 to antagonize its effect on chemoresistance. Exosome-mediated delivery of miR-374a-5p inhibitor could increase Neurod1 expression, promote cell apoptosis, and suppress chemoresistance. miR-374a-5p had a promoting role in gastric cancer chemoresistance, which would provide a novel biomarker for gastric cancer diagnosis and prognosis and offer a potential target for gastric cancer drug resistance therapy.

The latest progress on miR-374 and its functional implications in physiological and pathological processes

Non‐coding RNAs (ncRNAs) have been emerging players in cell development, differentiation, proliferation and apoptosis. Based on their differences in length and structure, they are subdivided into several categories including long non‐coding RNAs (lncRNAs >200nt), stable non‐coding RNAs (60‐300nt), microRNAs (miRs or miRNAs, 18‐24nt), circular RNAs, piwi‐interacting RNAs (26‐31nt) and small interfering RNAs (about 21nt). Therein, miRNAs not only directly regulate gene expression through pairing of nucleotide bases between the miRNA sequence and a specific mRNA that leads to the translational repression or degradation of the target mRNA, but also indirectly affect the function of downstream genes through interactions with lncRNAs and circRNAs. The latest studies have highlighted their importance in physiological and pathological processes. MiR‐374 family member are located at the X‐chromosome inactivation center. In recent years, numerous researches have uncovered that miR‐374 family members play an indispensable regulatory role, such as in reproductive disorders, cell growth and differentiation, calcium handling in the kidney, various cancers and epilepsy. In this review, we mainly focus on the role of miR‐374 family members in multiple physiological and pathological processes. More specifically, we also summarize their promising potential as novel prognostic biomarkers and therapeutic targets from bench to bedside.

Non-Coding RNAs and Resistance to Anticancer Drugs in Gastrointestinal Tumors

Non-coding RNAs are important regulators of gene expression and transcription. It is well established that impaired non-coding RNA expression especially the one of long non-coding RNAs and microRNAs is involved in a number of pathological conditions including cancer. Non-coding RNAs are responsible for the development of resistance to anticancer treatments as they regulate drug resistance-related genes, affect intracellular drug concentrations, induce alternative signaling pathways, alter drug efficiency via blocking cell cycle regulation, and DNA damage response. Furthermore, they can prevent therapeutic-induced cell death and promote epithelial-mesenchymal transition (EMT) and elicit non-cell autonomous mechanisms of resistance. In this review, we summarize the role of non-coding RNAs for different mechanisms resulting in drug resistance (e.g., drug transport, drug metabolism, cell cycle regulation, regulation of apoptotic pathways, cancer stem cells, and EMT) in the context of gastrointestinal cancers.

Downregulation of miR-374b-5p promotes chemotherapeutic resistance in pancreatic cancer by upregulating multiple anti-apoptotic proteins

Resistance to first-line chemotherapeutic drugs such as gemcitabine contributes to the poor prognosis of patients with pancreatic cancer. MicroRNAs (miRNA) regulate chemoresistance in pancreatic cancer. By analyzing the miRNA sequencing dataset of pancreatic cancer from The Cancer Genome Atlas, it was demonstrated that miR-374b-5p expression was dramatically reduced in pancreatic cancer tissues compared with adjacent normal tissues, as well as decreased in chemoresistant compared with chemosensitive pancreatic carcinoma tissues. The decreased expression of miR-374-5p was associated with poor overall and progression-free survival in patients with pancreatic cancer. Furthermore, increased expression of miR-374b-5p abrogated, while the silencing miR-374b-5p increased the chemoresistance of pancreatic cancer cells to gemcitabine in vitro. Importantly, the upregulation of miR-374b-5p ameliorated the chemoresistance of pancreatic cancer cells to gemcitabine in vivo. It was also demonstrated that miR-374b-5p targeted several anti-apoptotic proteins, including B-cell lymphoma 2, Baculoviral IAP Repeat Containing 3 and X-linked inhibitor of apoptosis in pancreatic cancer cells, which further attenuated chemo-resistance in pancreatic cancer. Therefore, the results of the current study indicate that miR-374b-5p serves as a potential diagnostic marker. It also suggests that miR-374b-5p sensitizes cells to chemotherapy and may be used in combination with chemotherapeutic agents such as gemcitabine to treat patients with pancreatic cancer.

MicroRNA-374b inhibits liver cancer progression via down regulating programmed cell death-1 expression on cytokine-induced killer cells

Programmed cell death-1 (PD-1) is an oncogene associated with suppressing proliferation and cytokine production of T cells in the progression of liver cancer. microRNAs (miRs) regulate gene expression via specific binding to the target 3′untranslated region of mRNA. In the present study, miR-374b was indicated to interact with PD-1 and affect the tumor-targeting capacity of cytokine-induced killer (CIK) cells. miR-374b inhibitor significantly increased PD-1 expression in CIK cells. A synthetic small interfering (si)RNA targeting PD-1 was employed to silence the expression level of PD-1 in CIK cells. Then, the antitumor effect of siPD-1 in CIK cells was investigated. In vitro study demonstrated that IFN-γ secretion and the concentration of lactate dehydrogenase were significantly increased in the PD-1 knockdown group; however, the viability of HepG2 cells in the PD-1 knockdown group had significantly decreased, compared with the HepG2 cells in the negative control group. In vivo study indicated that mice inoculated with HepG2 cells and CIK cells with PD-1 knocked down had a significantly smaller tumor volume, compared with the control group. To conclude, human CIK cells transfected with siPD-1 can target liver cancer cells and enhance immunotherapy efficacy, and therefore they have potential in the immunotherapy of liver cancer.

The role of miRNAs in the diagnosis, chemoresistance, and prognosis of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a very challenging malignancy with late presentation, metastatic potential, chemoresistance, and poor prognosis. Therefore, there is an urgent need for novel diagnostic and prognostic biomarkers. miRNAs are small noncoding RNAs that regulate the expression of multitude number of genes. Aberrant expression of miRNAs has been linked to the development of various malignancies, including PDAC. A series of miRNAs have been defined as holding promise for early diagnostics, as indicators of therapy resistance, and even as markers for prognosis in PDAC patients. In this review, we summarize the current knowledge on the role of miRNAs in diagnosis, chemoresistance, and prognosis in PDAC patients.

MicroRNA-374b reduces the proliferation and invasion of colon cancer cells by regulation of LRH-1/Wnt signaling

Deregulation of microRNA (miRNA) has been suggested as a critical event in colon cancer development and progression. Recent studies have suggested that miR-374b is a novel cancer-related miRNA involved in several cancer types. Thus far, very little is known about the role of miR-374b in colon cancer; therefore, the goal of this study was to investigate the potential role of miR-374b in colon cancer. Here, we showed that miR-374b expression was significantly downregulated in colon cancer tissues and cell lines. Overexpression of miR-374b inhibited the proliferation and invasion of colon cancer cells, while miR-374b suppression promoted colon cancer cell proliferation and invasion. Liver receptor homolog-1 (LRH-1) was identified as a target of miR-374b in colon cancer cells. Both the mRNA and protein expression of LRH-1 were regulated by miR-374b. In addition, an inverse correlation between LRH-1 mRNA and miR-374b expression was evidenced in colon cancer specimens. Notably, overexpression of miR-374b also downregulated the Wnt signaling in colon cancer cells. Furthermore, restoration of LRH-1 expression significantly abolished the antitumor effect of miR-374b in colon cancer cells. These findings suggest that miR-374b inhibits colon cancer cell proliferation and invasion through downregulation of LRH-1 expression. Inhibiting LRH-1 by miR-374b may represent a novel therapeutic strategy for the treatment of colon cancer.

MiR-629 promotes human pancreatic cancer progression by targeting FOXO3

The FOXO signaling pathway has been reported to have an important role in human cancer. Expression of miR-629 was markedly upregulated in pancreatic cancer and negatively correlated with FOXO3. Therefore, exploring the regulatory mechanism of miR-629 and FOXO3 signaling may provide valuable clinical targets for pancreatic cancer therapy. In the current study, we found that overexpressing and inhibiting miR-629, respectively, enhanced and reduced the cell proliferation and metastasis of pancreatic cancer cells in vitro and in vivo compared with parental cells or cells transfected with a control vector. Furthermore, we found that miR-629 negatively regulated FOXO3 protein expression and decreased the activity of a luciferase reporter construct containing the FOXO3 3′-untranslated region. These results show that miR-629 regulates FOXO3 at the posttranscriptional level, resulting in enhanced cell proliferation and invasion of pancreatic carcinoma. Furthermore, we found that overexpressing miR-629 enhanced, while inhibiting miR-629 reduced, the stem cell-like phenotype of pancreatic cancer cells in vitro. A functional polymorphism at miR-629-binding site in the 3′-UTR of FOXO3 gene confers a decreased risk of progression in pancreatic carcinoma. Furthermore, these findings suggest that miR-629 has a vital role in promoting the development of pancreatic cancer and may represent a novel prognostic biomarker and therapeutic target.

Small Nucleolar Noncoding RNA SNORA23, Up-Regulated in Human Pancreatic Ductal Adenocarcinoma, Regulates Expression of Spectrin Repeat-Containing Nuclear Envelope 2 to Promote Growth and Metastasis of Xenograft Tumors in Mice

BACKGROUND & AIMS

Small nucleolar noncoding RNAs (snoRNAs) regulate function of ribosomes, and specific snoRNAs are dysregulated in some cancer cells. We investigated dysregulation of snoRNAs in pancreatic ductal adenocarcinoma (PDAC) cells.

METHODS

We investigated snoRNA expression in PDAC cell lines by complementary DNA microarray and quantitative reverse transcription polymerase chain reaction. In PDAC (n = 133), intraductal papillary mucinous neoplasm (n = 16), mucinous cystic neoplasm-associated PDAC (n = 1), and non-tumor pancreas (n = 8) and liver (n = 3) tissues from subjects who underwent surgical resection, levels of snoRNA were measured by quantitative reverse transcription polymerase chain reaction and compared with clinicopathologic parameters and survival times determined by Kaplan-Meier analysis. To examine snoRNA function, PDAC cells were transfected with snoRNA-antisense oligonucleotides flanked with amido-bridged nucleic acids, or snoRNA-expression plasmids, and analyzed in proliferation, colony formation, spheroid formation, and invasion assays. To identify snoRNA-related factors, cells were analyzed by gene expression and proteomic profiling and immunoblot assays. Mice were given intrasplenic injections of MIA PaCa2- or Suit2-HLMC cells; tumor-bearing nude mice were then given 3 weekly injections of an antisense oligonucleotides against SNORA23, a H/ACA-box type snoRNA, and tumor growth and metastasis to liver, blood, and pancreas were analyzed.

RESULTS

Levels of SNORA23 increased and accumulated at the nucleolus in highly metastatic MIA PaCa2- or Suit2-HLMC cells compared with their parental cells. We detected SNORA23 in human PDAC specimens but not in non-tumor pancreatic tissue. PDAC level of SNORA23 correlated with invasion grade and correlated inversely with disease-free survival time of patients. Expression of SNORA23 in PDAC cells increased their invasive activity and colony formation, and spheroid formation was inhibited by SNORA23 knockdown. In gene expression and proteomic profile analyses, we found SNORA23 to increase expression of spectrin repeat-containing nuclear envelope 2 (SYNE2) messenger RNA and protein. Knockdown of SYNE2 in PDAC cells reduced their invasive activities and anchor-independent survival. Administration of SNORA23 antisense oligonucleotides to mice slowed growth of xenograft tumors, tumor expression of SYNE2, tumor cell dissemination, and metastasis to liver.

CONCLUSIONS

We found expression of the snoRNA SNORA23, which mediates sequence-specific pseudouridylation of ribosomal RNAs, to be increased in human PDAC tissues compared with non-tumor tissues, and levels to correlate with tumor invasion grade and patient survival time. SNORA23 increases expression of SYNE2, possibly through modulation of ribosome biogenesis, to promote PDAC cell survival and invasion, and growth and metastasis of xenograft tumors in mice.

Interactions between anticancer active platinum complexes and non-coding RNAs/microRNAs

Platinum(II) complexes such as cisplatin, carboplatin and oxaliplatin are clinically approved for the therapy of various solid tumors. Challenging pathogenic properties of cancer cells and the response of cancers towards platinum-based drugs are strongly influenced by non-coding small RNA molecules, the microRNAs (miRNAs). Both increased platinum activity and formation of tumor resistance towards platinum drugs are controlled by miRNAs. This review gives an overview of the interactions between platinum-based drugs and miRNAs, and their influence on platinum activity in various cancer types is discussed.

The underlying mechanisms of non-coding RNAs in the chemoresistance of pancreatic cancer

Pancreatic cancer, which is often asymptomatic, is currently one of the most common causes of cancer-related death. This phenomenon is most likely due to a lack of early diagnosis, a high metastasis rate and a disappointing chemotherapy outcome. Thus, improving treatment outcomes by overcoming chemotherapy resistance may be a useful strategy in pancreatic cancer. Various underlying mechanisms involved in the chemoresistance of pancreatic cancer have been investigated. Notably, non-coding RNAs (ncRNAs), especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play a pivotal role in regulating sensitivity to chemotherapy in pancreatic cancer. In this review, we highlight recent evidence regarding the role of miRNAs and lncRNAs in the chemoresistance of pancreatic cancer, including their expression levels, targets, biological functions and the regulation of chemoresistance, and discuss the potential clinical application of miRNAs and lncRNAs in the treatment of pancreatic cancer.