MiRNA-221-3p desensitizes pancreatic cancer cells to 5-fluorouracil by targeting RB1

Unraveling the MicroRNA tapestry: exploring the molecular dynamics of locoregional recurrent rectal cancer

Introduction

Colorectal cancer (CRC) ranks as the third most prevalent malignancy globally, with a concerning rise in incidence among young adults. Despite progress in understanding genetic predispositions and lifestyle risk factors, the intricate molecular mechanisms of CRC demand exploration. MicroRNAs (miRNAs) emerge as key regulators of gene expression and their deregulation in tumor cells play pivotal roles in cancer progression.

Methods

NanoString's nCounter technology was utilized to measure the expression of 827 cancer-related miRNAs in tumor tissue and adjacent non-involved normal colon tissue from five patients with locoregional CRC progression. These expression profiles were then compared to those from the primary colon adenocarcinoma (COAD) cohort in The Cancer Genome Atlas (TCGA).

Results and discussion

Intriguingly, 156 miRNAs showed a contrasting dysregulation pattern in reccurent tumor compared to their expression in the TCGA COAD cohort. This observation implies dynamic alterations in miRNA expression patterns throughout disease progression. Our exploratory study contributes to understanding the regulatory landscape of recurrent CRC, emphasizing the role of miRNAs in disease relapse. Notable findings include the prominence of let-7 miRNA family, dysregulation of key target genes, and dynamic changes in miRNA expression patterns during progression. Univariate Cox proportional hazard models highlighted miRNAs associated with adverse outcomes and potential protective factors. The study underscores the need for more extensive investigations into miRNA dynamics during tumor progression and the value of stage specific biomarkers for prognosis.

Functional and Potential Therapeutic Implication of MicroRNAs in Pancreatic Cancer

The alarmingly low five-year survival rate for pancreatic cancer presents a global health challenge, contributing to about 7% of all cancer-related deaths. Late-stage diagnosis and high heterogeneity are the biggest hurdles in treating pancreatic cancer. Thus, there is a pressing need to discover novel biomarkers that could help in early detection as well as improve therapeutic strategies. MicroRNAs (miRNAs), a class of short non-coding RNA, have emerged as promising candidates with regard to both diagnostics and therapeutics. Dysregulated miRNAs play pivotal roles in accelerating tumor growth and metastasis, orchestrating tumor microenvironment, and conferring chemoresistance in pancreatic cancer. The differential expression profiles of miRNAs in pancreatic cancer could be utilized to explore novel therapeutic strategies. In this review, we also covered studies on recent advancements in various miRNA-based therapeutics such as restoring miRNAs with a tumor-suppressive function, suppressing miRNA with an oncogenic function, and combination with chemotherapeutic drugs. Despite several challenges in terms of specificity and targeted delivery, miRNA-based therapies hold the potential to revolutionize the treatment of pancreatic cancer by simultaneously targeting multiple signaling pathways.

Investigating the regulatory role of miRNAs as silent conductors in the management of pathogenesis and therapeutic resistance of pancreatic cancer

Pancreatic cancer (PC) has the greatest mortality rate of all the main malignancies. Its advanced stage and poor prognosis place it at the bottom of all cancer sites. Hence, emerging biomarkers can enable precision medicine where PC therapy is tailored to each patient. This highlights the need for new, highly sensitive and specific biomarkers for early PC diagnosis. Prognostic indicators are also required to stratify PC patients. To avoid ineffective treatment, adverse events, and expenses, biomarkers are also required for patient monitoring and identifying responders to treatment. There is substantial evidence that microRNAs (miRs, miRNAs) play a critical role in regulating mRNA and, as a consequence, protein expression in normal and malignant tissues. Deregulated miRNA profiling in PC can help with diagnosis, treatment planning, and prognosis. Furthermore, knowledge of the primary effector genes and downstream pathways in PC can help pinpoint potential miRNAs for use in treatment. Different miRNA expression profiles may serve as diagnostic, prognostic markers, and therapeutic targets across the spectrum of malignant pancreatic illness. Dysregulation of miRNAs has been linked to the malignant pathophysiology of PC through affecting many cellular functions such as increasing invasive and proliferative prospect, supporting angiogenesis, cell cycle aberrance, apoptosis elusion, metastasis promotion, and low sensitivity to particular treatments. Accordingly, in the current review, we summarize the recent advances in the roles of oncogenic and tumor suppressor (TS) miRNAs in PC and discuss their potential as worthy diagnostic and prognostic biomarkers for PC, as well as their significance in PC pathogenesis and anticancer drug resistance.

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.

Chemoresistance in pancreatic ductal adenocarcinoma: Overcoming resistance to therapy

Pancreatic ductal adenocarcinoma (PDAC), a prominent cause of cancer deaths worldwide, is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. More than 90% of patients with PDAC die within a year of being diagnosed. PDAC is increasing at a rate of 0.5-1.0% per year, and it is expected to be the second leading cause of cancer-related mortality by 2030. The resistance of tumor cells to chemotherapeutic drugs, which can be innate or acquired, is the primary factor contributing to the ineffectiveness of cancer treatments. Although many PDAC patients initially responds to standard of care (SOC) drugs they soon develop resistance caused partly by the substantial cellular heterogeneity seen in PDAC tissue and the tumor microenvironment (TME), which are considered key factors contributing to resistance to therapy. A deeper understanding of molecular mechanisms involved in PDAC progression and metastasis development, and the interplay of the TME in all these processes is essential to better comprehend the etiology and pathobiology of chemoresistance observed in PDAC. Recent research has recognized new therapeutic targets ushering in the development of innovative combinatorial therapies as well as enhancing our comprehension of several different cell death pathways. These approaches facilitate the lowering of the therapeutic threshold; however, the possibility of subsequent resistance development still remains a key issue and concern. Discoveries, that can target PDAC resistance, either alone or in combination, have the potential to serve as the foundation for future treatments that are effective without posing undue health risks. In this chapter, we discuss potential causes of PDAC chemoresistance and approaches for combating chemoresistance by targeting different pathways and different cellular functions associated with and mediating resistance.

circACTR2 attenuates gemcitabine chemoresiatance in pancreatic cancer through PTEN mediated PI3K/AKT signaling pathway

BACKGROUND

Recently, accumulating studies have unveiled that circRNAs exert critical function in a variety of tumor biological processes including chemoresistance. Our previous study has found circACTR2 is significantly down-regulated in acquired gemcitabine (GEM)- resistant pancreatic cancer (PC) cells, which has not been well-explored. Our study aimed to research the function and molecular mechanism of circACTR2 in PC chemoresistance.

METHODS

qRT-PCR and western blot analysis was performed to detect gene expression. The effect of circACTR2 on PC GEM resistance were examined by CCK-8 and flow cytometry assays. Whether circACTR2 could sponge miR-221-3p and regulate PTEN expression were determined by bioinformatics analysis, RNA pull-down, and Dual-luciferase reporter assay.

RESULTS

circACTR2 was notably down-regulated in a panel of GEM-resistant PC cells lines, and negatively associated with aggressive phenotype and poor prognosis of PC. circACTR2 downregulation contributed to GEM chemoresistance of PC cells with decreased S phase ratio of cell cycle and cell apoptosis, as confirmed by gain- and loss-of-function assays in vitro. In addition, circACTR2 overexpression retarded GEM resistance in vivo. Further, circACTR2 acted as a ceRNA against miR-221-3p, which directly targeted PTEN. The mechanistic studies revealed that loss of circACTR2 promoted GEM resistance in PC through activating the PI3K/AKT signaling pathway by downregulating PTEN expression in a miR-221-3p dependent manner.

CONCLUSIONS

circACTR2 reversed the chemoresistance of PC cells to GEM through inhibiting PI3K/AKT signaling pathway by sponging miR-221-3p and upregulating PTEN expression.

TP63 Functions as a Tumor Suppressor Regulated by GAS5/miR-221-3p Signaling Axis in Human Non-Small Cell Lung Cancer Cells

Background

Tumor protein p63 (TP63) has been proven to play a role as a tumor suppressor in some human cancers, including non-small cell lung cancer (NSCLC). This study aimed to investigate the mechanism of TP63 and analyze the underlying pathway dysregulating TP63 in NSCLC.

Methods

RT-qPCR and Western blotting assays were used to determine gene expression in NSCLC cells. The luciferase reporter assay was performed to explore the transcriptional regulation. Flow cytometry was used to analyze the cell cycle and cell apoptosis. Transwell and CCK-8 assays were performed to test cell invasion and cell proliferation, respectively.

Results

GAS5 interacted with miR-221-3p, and its expression was significantly reduced in NSCLC. GAS5, as a molecular sponge, upregulated the mRNA and protein levels of TP63 by inhibiting miR-221-3p in NSCLC cells. The upregulation of GAS5 inhibited cell proliferation, apoptosis, and invasion, which was partially reversed by the knockdown of TP63. Interestingly, we found that GAS5-induced TP63 upregulation promoted tumor chemotherapeutic sensitivity to cisplatin therapy in vivo and in vitro.

Conclusion

Our results revealed the mechanism by which GAS5 interacts with miR-221-3p to regulate TP63, and targeting GAS5/miR-221-3p/TP63 may be a potential therapeutic strategy for NSCLC cells.

BNEMDI: A Novel MicroRNA–Drug Interaction Prediction Model Based on Multi-Source Information With a Large-Scale Biological Network

As a novel target in pharmacy, microRNA (miRNA) can regulate gene expression under specific disease conditions to produce specific proteins. To date, many researchers leveraged miRNA to reveal drug efficacy and pathogenesis at the molecular level. As we all know that conventional wet experiments suffer from many problems, including time-consuming, labor-intensity, and high cost. Thus, there is an urgent need to develop a novel computational model to facilitate the identification of miRNA–drug interactions (MDIs). In this work, we propose a novel bipartite network embedding-based method called BNEMDI to predict MDIs. First, the Bipartite Network Embedding (BiNE) algorithm is employed to learn the topological features from the network. Then, the inherent attributes of drugs and miRNAs are expressed as attribute features by MACCS fingerprints and k-mers. Finally, we feed these features into deep neural network (DNN) for training the prediction model. To validate the prediction ability of the BNEMDI model, we apply it to five different benchmark datasets under five-fold cross-validation, and the proposed model obtained excellent AUC values of 0.9568, 0.9420, 0.8489, 0.8774, and 0.9005 in ncDR, RNAInter, SM2miR1, SM2miR2, and SM2miR MDI datasets, respectively. To further verify the prediction performance of the BNEMDI model, we compare it with some existing powerful methods. We also compare the BiNE algorithm with several different network embedding methods. Furthermore, we carry out a case study on a common drug named 5-fluorouracil. Among the top 50 miRNAs predicted by the proposed model, there were 38 verified by the experimental literature. The comprehensive experiment results demonstrated that our method is effective and robust for predicting MDIs. In the future work, we hope that the BNEMDI model can be a reliable supplement method for the development of pharmacology and miRNA therapeutics.

Identification of an interactome network between lncRNAs and miRNAs in thyroid cancer reveals SPTY2D1-AS1 as a new tumor suppressor

Thyroid cancer is the most common primary endocrine malignancy in adults and its incidence is rapidly increasing. Long non-coding RNAs (lncRNAs), generally defined as RNA molecules longer than 200 nucleotides with no protein-encoding capacity, are highly tissue-specific molecules that serve important roles in gene regulation through a variety of different mechanisms, including acting as competing endogenous RNAs (ceRNAs) that ‘sponge’ microRNAs (miRNAs). In the present study, using an integrated approach through RNA-sequencing of paired thyroid tumor and non-tumor samples, we have identified an interactome network between lncRNAs and miRNAs and examined the functional consequences in vitro and in vivo of one of such interactions. We have identified a likely operative post-transcriptional regulatory network in which the downregulated lncRNA, SPTY2D1-AS1, is predicted to target the most abundant and upregulated miRNAs in thyroid cancer, particularly miR-221, a well-known oncomiRNA in cancer. Indeed, SPTY2D1-AS1 functions as a potent tumor suppressor in vitro and in vivo, it is downregulated in the most advanced stages of human thyroid cancer, and it seems to block the processing of the primary form of miR-221. Overall, our results link SPTY2D1-AS1 to thyroid cancer progression and highlight the potential use of this lncRNA as a therapeutic target of thyroid cancer.

miR-221/222 as biomarkers and targets for therapeutic intervention on cancer and other diseases: A systematic review

Among deregulated microRNAs (miRs) in human malignancies, miR-221 has been widely investigated for its oncogenic role and as a promising biomarker. Moreover, recent evidence suggests miR-221 as a fine-tuner of chronic liver injury and inflammation-related events. Available information also supports the potential of miR-221 silencing as promising therapeutic intervention. In this systematic review, we selected papers from the principal databases (PubMed, MedLine, Medscape, ASCO, ESMO) between January 2012 and December 2020, using the keywords “miR-221” and the specific keywords related to the most important hematologic and solid malignancies, and some non-malignant diseases, to define and characterize deregulated miR-221 as a valuable therapeutic target in the modern vision of molecular medicine. We found a major role of miR-221 in this view.

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.

MicroRNAs as potential therapeutic targets for pancreatic cancer

ABSTRACT

Pancreatic cancer is one of the most aggressive malignancies. The poor prognosis of pancreatic cancer patients is mainly attributed to low diagnostic rate at the early stage, highly aggressive nature coupled with the inadequate efficacy of current chemotherapeutic regimens. Novel therapeutic strategies are urgently needed for pancreatic cancer. MicroRNAs (miRNAs) play an important regulatory role in key processes of cancer development. The aberrant expression of miRNAs is often involved in the initiation, progression, and metastasis of pancreatic cancer. The discovery of tumor suppressor miRNAs provides prospects for the development of a novel treatment strategy for pancreatic cancer. We reviewed recent progress on the understanding of the role of miRNAs in pancreatic cancer, highlighted the efficient application of miRNAs-based therapies for pancreatic cancer in animal models and clinical trials, and proposed future prospects. This review focuses on the promise of integrating miRNAs into the treatment of pancreatic cancer and provides guidance for the development of precision medicine for pancreatic cancer.

Clinical Significance and Underlying Mechanisms of CELSR3 in Metastatic Prostate Cancer Based on Immunohistochemistry, Data Mining, and In Silico Analysis

Background: The treatment and survival rate of patients with metastatic prostate cancer (MPCa) remain unsatisfactory. Herein, the authors investigated the clinical value and potential mechanisms of cadherin EGF LAG seven-pass G-type receptor 3 (CELSR3) in MPCa to identify novel targets for clinical diagnosis and treatment. Materials and Methods: mRNA microarray and RNA-Seq (n = 1246 samples) data were utilized to estimate CELSR3 expression and to assess its differentiation ability in MPCa. Similar analyses were performed with miRNA-221-3p. Immunohistochemistry performed on clinical samples were used to evaluate the protein expression level of CELSR3 in MPCa. Based on CELSR3 differentially coexpressed genes (DCEGs), enrichment analysis was performed to investigate potential mechanisms of CELSR3 in MPCa. Results: The pooled standard mean difference (SMD) for CELSR3 was 0.80, demonstrating that CELSR3 expression was higher in MPCa than in localized prostate cancer (LPCa). CELSR3 showed moderate potential to distinguish MPCa from LPCa. CELSR3 protein expression was found to be markedly upregulated in MPCa than in LPCa tissues. The authors screened 894 CELSR3 DCEGs, which were notably enriched in the focal adhesion pathway. miRNA-221-3p showed a significantly negative correlation with CELSR3 in MPCa. Besides, miRNA-221-3p expression was downregulated in MPCa than in LPCa (SMD = -1.04), and miRNA-221-3p was moderately capable of distinguishing MPCa from LPCa. Conclusions: CELSR3 seems to play a pivotal role in MPCa by affecting the focal adhesion pathway and/or being targeted by miRNA-221-3p.

Retinoblastoma tumor suppressor gene 1 enhances 5-Fluorouracil chemosensitivity through SDF-1/CXCR4 axis by regulating autophagy in gastric cancer

Due to lack of effective biomarkers for early diagnosis, most patients are diagnosed with advanced gastric cancer and have lower survival rates. 5-Fluorouracil (5-FU) is one of commonly used drugs for chemotherapy of gastric cancer, but drug resistance limits the wide application of agents. Retinoblastoma tumor suppressor gene 1 (RB1) is a key regulator in the progression of various human cancers, including gastric cancer. However, the effects of RB1 on chemosensitivity and the underlying mechanisms in gastric cancer (GC) are not clear. In this study, expressions of RB1 in GC cell lines were evaluated by RT-qPCR and western blot assay. CCK-8 was applied to examine the effect of 5-FU on cell viability. Meanwhile, IC50 values were calculated. The drug-resistance protein MDR1 and autophagy-related proteins were detected by western blot assay. Flow cytometry was used to detect cell cycle. The results showed that RB1 expressions were downregulated in GC cell lines and had significant differences between 5-FU resistance cell lines (SNU-620/5-FU and NUGC-3/5-FU) and non-resistance cell lines (SNU-620 and NUGC-3). Overexpression of RB1 enhanced 5-FU sensitivity of GC cells and caused cell cycle arrest in the S phase. Meanwhile, autophagy-related proteins were downregulated. Mechanistically, SDF-1/CXCR4 participated in the regulation of RB1 on cell autophagy. Autophagy activator, SDF-1 treatment and CXCR4 activation reversed the promoted effects of RB1 on 5-FU sensitivity in GC cells. In conclusion, our data revealed that RB1 was downregulated in GC cell lines. RB1 overexpression enhanced 5-FU chemosensitivity in GC cells by regulating cell autophagy via SDF-1/CXCR4 pathway. RB1 might serve as a promising therapeutic target of GC.

MiRNA-107 enhances the malignant progression of pancreatic cancer by targeting TGFBR3

Background

The prognosis of pancreatic cancer (PC) is relatively dismal due to the lack of effective therapy. In this study, we explored the specific functions and molecular mechanisms of miR-107 to uncover effective therapeutic targets for PC.

Method

The miR-107 expression in PC cell lines was assessed via quantitative real-time polymerase chain reaction (qRT-PCR). Besides, online bioinformatics analysis was adopted to predict the underlying targets of miR-107. Meanwhile, TCGA database was employed to explore the prognosis of PC patients. In addition, MTT and transwell assays were conducted to explore the PC cells’ biological functions.

Result

MiR-107 was remarkably increased in PC cells which could promote the proliferation, invasion and migration of PC cells. In addition, miR-107 could directly down-regulate TGFBR3 expression through binding to TGFBR3 3’UTR. Survival analysis from TCGA suggested that PC patients with higher miR-107 expression was significantly involved in poorer prognosis.

Conclusion

We concluded that miR-107 promoted proliferation, invasion and migration of PC cells via targeting TGFBR3, which may provide novel underlying therapeutic targets.

MiR-221-3p-mediated downregulation of MDM2 reverses the paclitaxel resistance of non-small cell lung cancer in vitro and in vivo

MicroRNAs (miRNAs) are involved in the initiation and development of cancer and participate in drug resistance. Paclitaxel (PTX) is a first-line chemotherapy drug for advanced non-small cell lung cancer (NSCLC). The abnormal miRNA expression in NSCLC and its association with chemotherapy drug resistance remains largely unknown. The study aimed to investigate the aberrant expression of miR-221-3p in NSCLC and to elucidate its molecular mechanisms in relation to PTX resistance. PTX increased miR-221-3p expression and regulated MDM2/P53 expression in the PTX-sensitive NSCLC strain (A549). Meanwhile, miR-221-3p was rarely expressed and not interfered by PTX in PTX-resistant A549 cells (A549/Taxol). Dual-luciferase reporter assay confirmed that miR-221-3p specifically binds to MDM2 messenger RNA and inhibited MDM2 expression. The expression of MDM2 and P53 showed a negative correlation in NSCLC cell lines. MiR-221-3p down-regulation reduced the sensitivity of A549 cells to PTX, whereas its up-regulation partially reversed the A549/Taxol cells resistance to PTX and increased the chemosensitivity of A549/Taxol cells to PTX in xenograft models. Quantitative polymerase chain reaction analysis revealed that miR-221-3p expression increased, whereas the MDM2 level decreased in human NSCLC tumor tissues. Moreover, Western bolt analysis showed that P53 was lowly expressed in tumor tissues with MDM2 overexpression. Low expression of miR-221-3p in NSCLC tissues might indicate a poor T staging. In conclusion, miR-221-3p overexpression could regulate MDM2/p53 signaling pathway to reverse the PTX resistance of NSCLC and induce apoptosis in vitro and vivo.

5-Fluorouracil: A Narrative Review on the Role of Regulatory Mechanisms in Driving Resistance to This Chemotherapeutic Agent

5-fluorouracil (5-FU) is among the mostly administrated chemotherapeutic agents for a wide variety of neoplasms. Non-coding RNAs have a central impact on the determination of the response of patients to 5-FU. These transcripts via modulation of cancer-related pathways, cell apoptosis, autophagy, epithelial-mesenchymal transition, and other aspects of cell behavior can affect cell response to 5-FU. Modulation of expression levels of microRNAs or long non-coding RNAs may be a suitable approach to sensitize tumor cells to 5-FU treatment via modulating multiple biological signaling pathways such as Hippo/YAP, Wnt/β-catenin, Hedgehog, NF-kB, and Notch cascades. Moreover, there is an increasing interest in targeting these transcripts in various kinds of cancers that are treated by 5-FU. In the present article, we provide a review of the function of non-coding transcripts in the modulation of response of neoplastic cells to 5-FU.

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.

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.

Connecting the Missing Dots: ncRNAs as Critical Regulators of Therapeutic Susceptibility in Breast Cancer

Whether acquired or de novo, drug resistance remains a significant hurdle in achieving therapeutic success in breast cancer (BC). Thus, there is an urge to find reliable biomarkers that will help in predicting the therapeutic response. Stable and easily accessible molecules such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are regarded as valuable prognostic biomarkers and therapeutic targets since they act as crucial regulators of the various mechanisms involved in BC drug resistance. Here, we reviewed the current literature on ncRNAs as mediators of resistance to systemic therapies in BC. Interestingly, upon integrating data results from individual studies, we concluded that miR-221, miR-222, miR-451, Urothelial Carcinoma Associated 1 (UCA1), and Growth arrest-specific 5 (GAS5) are strong candidates as prognostic biomarkers and therapeutic targets since they are regulating multiple drug resistance phenotypes in BC. However, further research around their clinical implications is needed to validate and integrate them into therapeutic applications. Therefore, we believe that our review may provide relevant evidence for the selection of novel therapeutic targets and prognostic biomarkers for BC and will serve as a foundation for future translational research in the field.

MicroRNA-221-3p is related to survival and promotes tumour progression in pancreatic cancer: a comprehensive study on functions and clinicopathological value

Background

The microRNA miR-221-3p has previously been found to be an underlying biomarker of pancreatic cancer. However, the mechanisms of miR-221-3p underlying its role in pancreatic cancer pathogenesis, proliferation capability, invasion ability, drug resistance and apoptosis and the clinicopathological value of miR-221-3p have not been thoroughly studied.

Methods

Based on microarray and miRNA-sequencing data extracted from Gene Expression Omnibus (GEO), The Cancer Genome Atlas (TCGA), relevant literature, and real-time quantitative PCR (RT-qPCR), we explored clinicopathological features and the expression of miR-221-3p to determine its clinical effect in pancreatic cancer. Proliferation, migration, invasion, apoptosis and in vitro cytotoxicity tests were selected to examine the roles of mir-221-3p. In addition, several miR-221-3p functional analyses were conducted, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Protein–protein interaction (PPI) network analyses, to examine gene interactions with miR-221-3p.

Results

The findings of integrated multi-analysis revealed higher miR-221-3p expression in pancreatic cancer tissues and blood than that in para-carcinoma samples (SMD of miR-221-3p: 1.52; 95% CI 0.96, 2.08). MiR-221-3p is related to survival both in pancreatic cancer and pancreatic ductal adenocarcinoma patients. Cell experiments demonstrated that miR-221-3p promotes pancreatic cancer cell proliferation capability, migration ability, invasion ability, and drug resistance but inhibits apoptosis. Further pancreatic cancer bioinformatics analyses projected 30 genes as the underlying targets of miR-221-3p. The genes were significantly distributed in diverse critical pathways, including microRNAs in cancer, viral carcinogenesis, and the PI3K-Akt signalling pathway. Additionally, PPI indicated four hub genes with threshold values of 5: KIT, CDKN1B, RUNX2, and BCL2L11. Moreover, cell studies showed that miR-221-3p can inhibit these four hub genes expression in pancreatic cancer.

Conclusions

Our research revealed that pancreatic cancer expresses a high-level of miR-221-3p, indicating a potential miR-221-3p role as a prognosis predictor in pancreatic cancer. Moreover, miR-221-3p promotes proliferation capacity, migration ability, invasion ability, and drug resistance but inhibits apoptosis in pancreatic cancer. The function of miR-221-3p in the development of pancreatic cancer may be mediated by the inhibition of hub genes expression. All these results might provide an opportunity to extend the understanding of pancreatic cancer pathogenesis.

Could Protons and Carbon Ions Be the Silver Bullets Against Pancreatic Cancer?

Pancreatic cancer is a very aggressive cancer type associated with one of the poorest prognostics. Despite several clinical trials to combine different types of therapies, none of them resulted in significant improvements for patient survival. Pancreatic cancers demonstrate a very broad panel of resistance mechanisms due to their biological properties but also their ability to remodel the tumour microenvironment. Radiotherapy is one of the most widely used treatments against cancer but, up to now, its impact remains limited in the context of pancreatic cancer. The modern era of radiotherapy proposes new approaches with increasing conformation but also more efficient effects on tumours in the case of charged particles. In this review, we highlight the interest in using charged particles in the context of pancreatic cancer therapy and the impact of this alternative to counteract resistance mechanisms.

Prognostic value of microRNAs in pancreatic cancer: a meta-analysis

BACKGROUND

The prognostic impact of microRNA (miRNA) expression levels in pancreatic cancer (PC) has been estimated for years, but the outcomes are controversial and heterogeneous. Therefore, we comprehensively reviewed the evidence collected on miRNA expression in PC to determine this effect.

RESULTS

PC patients with high miR-21 (HR=2.61, 95%CI=1.68-4.04), miR-451a (HR=2.23, 95%CI=1.23-4.04) or miR-1290 (HR=1.43, 95%CI=1.04-1.95) levels in blood had significantly poorer OS (P<0.05). Furthermore, PC patients with high miR-10b (HR=1.73, 95%CI=1.09-2.76), miR-17-5p (HR=1.91, 95%CI=1.30-2.80), miR-21 (HR=1.90, 95%CI=1.61-2.25), miR-23a (HR=2.18, 95%CI=1.52-3.13), miR-155 (HR=2.22, 95%CI=1.27-3.88), miR-203 (HR=1.65, 95%CI=1.14-2.40), miR-221 (HR=1.72, 95%CI=1.08-2.74), miR-222 levels (HR=1.72, 95%CI=1.02-2.91) or low miR-29c (HR=1.39, 95%CI=1.08-1.79), miR-126 (HR=1.55, 95%CI=1.23-1.95), miR-218 (HR=2.62, 95%CI=1.41-4.88) levels in tissues had significantly shorter OS (P<0.05).

CONCLUSIONS

In summary, blood miR-21, miR-451a, miR-1290 and tissue miR-10b, miR-17-5p, miR-21, miR-23a, miR-29c, miR-126, miR-155, miR-203, miR-218, miR-221, miR-222 had significant prognostic value.

METHODS

We searched PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews to recognize eligible studies, and 57 studies comprising 5445 PC patients and 15 miRNAs were included to evaluate the associations between miRNA expression levels and overall survival (OS) up to June 1, 2019. Summary hazard ratios (HR) with 95% confidence intervals (CI) were calculated to assess the effect.

Exosomal MicroRNA-221-3p Confers Adriamycin Resistance in Breast Cancer Cells by Targeting PIK3R1

Drug resistance in breast cancer (BC) cells continues to be a stern obstacle hindering BC treatment. Adriamycin (ADR) is a frequently employed chemotherapy agent used to treat BC. The exosomal transfer of microRNAs (miRNAs) has been reported to enhance the drug-resistance of BC cells. Herein, we first sought to elucidate the possible role of the exosomal transfer of miR-221-3p in the drug resistance of MCF-7 cells to ADR. Differentially expressed genes (DEGs) were initially screened through microarray analysis in BC drug resistance-related datasets. Next, the expression of miR-221-3p and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) was quantified in ADR-resistant MCF-7 (MCF-7/ADR) and ADR-sensitive MCF-7 (MCF-7/S) cell lines, after which exosomes were separated and identified in each cell line. Target relationship between miR-221-3p and PIK3R1 was validated by a dual-luciferase reporter assay. Next, the expression of miR-221-3p and PIK3R1 was altered to clarify their effects on the resistance of MCF-7 cells to ADR in vitro and in vivo. PIK3R1 was identified as a BC drug resistance-related DEG, with the regulatory miR-221-3p subsequently obtained. Moreover, the MCF-7/ADR cells exhibited a low expression of PIK3R1 and a high expression of miR-221-3p. Notably, PIK3R1 was identified as a target gene of miR-221-3p. The overexpression of miR-221-3p in MCF-7/ADR cell-derived exosomes promoted ADR resistance in MCF-7/S cells via the PI3K/AKT signaling pathway. The in vitro results were reproducible in in vivo assays. Taken together, drug-resistant BC cell-derived exosomal miR-221-3p can promote the resistance of BC cells to ADR by targeting PIK3R1 via the PI3K/AKT signaling pathway in vitro and in vivo. These findings provide encouraging insights and provide perspectives for further investigation into the BC drug resistance mechanism.

Downregulation of miR-486-5p Enhances the Anti-Tumor Effect of 5-Fluorouracil on Pancreatic Cancer Cells

Background

5-Fluorouracil (5-Fu) has been applied to treat pancreatic cancer, which is one of the most common types of digestive system tumors. Evidence has shown that miR-486-5p could promote the proliferation of pancreatic cancer cells. Therefore, this study aimed to investigate whether downregulation of miR-486-5p could enhance the anti-tumor effect of 5-Fu on pancreatic cancer cells.

Methods

Cell Counting Kit 8 assay, flow cytometry and wound healing assays were used to detect proliferation, apoptosis and migration in PANC-1 cells. The expressions of Bcl-2, Bax, cleaved caspase 3, PTEN, p-Akt and p-ERK in PANC-1 cells were detected with Western blot assay.

Results

In this study, the inhibitory effects of 5-Fu on the proliferation, migration and invasion of PANC-1 cells were significantly enhanced following transfection with miR-486-5p antagonist. In addition, downregulation of miR-486-5p markedly enhanced the pro-apoptosis effect of 5-Fu on PANC-1 cells. Moreover, bioinformatics analysis and luciferase reporter assay identified that PTEN was the directly binding target of miR-486-5p. Meanwhile, downregulation of miR-486-5p markedly enhanced the anti-tumor effect of 5-Fu in PANC-1 cells via upregulation of the level of PTEN, and downregulation of the expressions of p-ERK and p-Akt. In vivo experiments confirmed that knockdown of miR-486-5p could enhance the anti-tumor effect of 5-Fu in PANC-1 xenograft model.

Conclusion

We found that the downregulation of miR-486-5p could enhance the anti-tumor effect of 5-Fu on pancreatic cancer cells. Therefore, miR-486-5p antagonist plus 5-Fu might be considered as a potential therapeutic strategy for the treatment of pancreatic cancer.

Cervical Cancer Cells-Secreted Exosomal microRNA-221-3p Promotes Invasion, Migration and Angiogenesis of Microvascular Endothelial Cells in Cervical Cancer by Down-Regulating MAPK10 Expression

Purpose

Cervical cancer (CC) is recognized as a common cancer with a high risk worldwide. Exosomal microRNAs (miRNAs) have received attention for their increasing potentials in CC therapy. In this study, we identify the involvement of miR-221-3p in CC progression by affecting angiogenesis of microvascular endothelial cells (MVECs).

Methods

Microarray-based gene expression profiling was conducted to retrieve the differentially expressed genes in CC. The expression patterns of miR-221-3p were measured by RT-qPCR, while Western blot analysis and RT-qPCR were performed to determine the expression of MAPK10 in the CC tissues and cells, followed by verification of the interaction between miR-221-3p and MAPK10 using dual luciferase reporter gene assay. Then the effects of miR-221-3p and MAPK10 on cell activities were assessed through gain- and loss-of-function experiments in CC. Subsequently, the impact of exosomal miR-221-3p on MVEC proliferation, migration, invasion and angiogenesis was examined after exosomal isolation from CC cells and co-cultured with MVECs.

Results

Gene expression profile showed that MAPK10 might participate in CC with a low expression. Moreover, miR-221-3p was highly expressed and MAPK10 was poorly expressed in CC tissues and cells. It was observed that miR-221-3p targeted MAPK10. Depletion of miR-221-3p blocked the cell proliferation, invasion and migration in CC by up-regulating MAPK10. Moreover, CC cells-derived exosomes carrying miR-221-3p accelerated MVEC proliferation, invasion, migration and angiogenesis in CC by regulating MAPK10.

Conclusion

CC cells-derived exosomes harboring miR-221-3p enhanced MVEC angiogenesis in CC by decreasing MAPK10.

Non-Coding RNAs in Retinoblastoma

Retinoblastoma (Rb) is the most common ocular pediatric malignancy that arises from the retina and is caused by a mutation of the two alleles of the tumor suppressor gene, RB1. Although early detection provides the opportunity of controlling the primary tumor with effective therapies, metastatic activity is fatal. Non-coding RNAs (ncRNAs) have emerged as important modifiers of a plethora of biological mechanisms including those involved in cancer. They are classified into short and long ncRNAs according to their length. Deregulation of all these molecules has also been shown to play a critical role in Rb pathogenesis and progression. It is believed that ncRNAs can provide new insights into novel regulatory mechanisms associated with clinical pathological characteristics, facilitating the development of therapeutic alternatives for the treatment of Rb. In this review, we describe a variety of ncRNAs, which capable of regulating the most likely candidate genes involved in the tumorigenesis of Rb, could prove useful in analyzing different aspects of this cancer.

Development of microRNA-based therapy for pancreatic cancer

Despite extensive research efforts on diagnosis and treatment, pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease and the third leading cause of cancer-related death in the United States. Resistance to current therapeutic approaches is a major reason for the poor survival of pancreatic patients. In order to overcome this major challenge and improve patient outcomes, we are in desperate need of novel therapeutic approaches. PDAC chemoresistance mechanisms are complex and multifaceted. Novel therapeutics must be equipped to deal with this challenge. microRNAs (miRNAs) have emerged as strong candidates to fill this role due to their multitargeted function. miRNAs have been shown to have important roles in pancreatic cancer resistance. In this review, we summarize the recent advancement in miRNA research related to PDAC therapeutic resistance mechanisms and the potential of miRNAs as therapeutic agents for future clinical management of PDAC.

MicroRNAs as Potential Biomarkers for Chemoresistance in Adenocarcinomas of the Esophagogastric Junction

Concerning adenocarcinomas of the esophagogastric junction, neoadjuvant chemotherapy is regularly implemented, but patients' response varies greatly, with some cases showing no therapeutic effect, being deemed as chemoresistant. Small, noncoding RNAs (miRNAs) have evolved as key players in biological processes, including malignant diseases, often promoting tumor growth and expansion. In addition, specific miRNAs have been implicated in the development of chemoresistance through evasion of apoptosis, cell cycle alterations, and drug target modification. We performed a retrospective study of 33 patients receiving neoadjuvant chemotherapy by measuring their miRNA expression profiles. Histologic tumor regression was evaluated using resection specimens, while miRNA profiles were prepared using preoperative biopsies without prior therapy. A preselected panel of 96 miRNAs, known to be of importance in various malignancies, was used to test for significant differences between responsive (chemosensitive) and nonresponsive (chemoresistant) cases. The cohort consisted of 12 nonresponsive and 21 responsive cases with the following 4 miRNAs differentially expressed between both the groups: hsa-let-7f-5p, hsa-miRNA-221-3p, hsa-miRNA-31-5p, and hsa-miRNA-191-5p. The former 3 showed upregulation in chemoresistant cases, while the latter showed upregulation in chemosensitive cases. In addition, significant correlation between high expression of hsa-miRNA-194-5p and prolonged survival could be demonstrated (p value <0.0001). In conclusion, we identified a panel of 3 miRNAs predicting chemoresistance and a single miRNA contributing to chemosensitivity. These miRNAs might function as prognostic biomarkers and enable clinicians to better predict the effect of one or more reliably select patients benefitting from (neoadjuvant) chemotherapy.

Potential of C1QTNF1-AS1 regulation in human hepatocellular carcinoma

The aim of our study is to explore the regulation of C1QTNF1-AS1 on its target miR-221-3p/SOCS3 in human hepatocellular carcinoma (HCC). To explore the underlying molecular regulation of non-coding RNA for HCC, differentially expressed patterns of lncRNAs and genes were examined by RNA-seq. GO and KEGG pathway analysis were done based on the function of mRNAs that mediated by differentially expressed lncRNAs. RT-qPCR and western blot were conducted to detect the mRNA and protein level expression of C1QTNF1-AS1, miR-221-3p, SOCS3 and key proteins in JAK/STAT signaling pathway in HCC tissues and cells. The target miRNA of differentially expressed C1QTNF1-AS1 and SOCS3 was miR-221-3p predicted by bioinformatics analysis. C1QTNF1-AS1 and SOCS3 was downregulated and miR-221-3p was upregulated in HCC tissues and cells. In HepG2 and Huh-7 cells, the overexpression of C1QTNF1-AS1 or SOCS3, and silencing of miR-221-3p inhibited proliferation, migration, invasion and JAK/STAT signaling pathway, while promoted cell apoptosis. The results of dual-luciferase assay indicated that C1QTNF1-AS1 regulated miR-221-3p and miR-221-3p targeted SOCS3 by directly binding. And the growth of HCC in vivo was impeded when C1QTNF1-AS1 was upregulated. Overexpression of C1QTNF1-AS1 could downregulate miR-221-3p thereby inhibited the proliferation, migration and invasion of HCC cells.

C1QTNF1-AS1 regulates the occurrence and development of hepatocellular carcinoma by regulating miR-221-3p/SOCS3

BACKGROUND

The aim of our study was to explore how C1QTNF1-AS1 regulated miR-221-3p/SOCS3 axis in human hepatocellular carcinoma (HCC).

METHODS

Differentially expressed lncRNAs and genes were examined via RNA-seq. GO analysis and KEGG pathway enrichment analysis were carried out based on the function of dys-regulated mRNAs. RT-qPCR was employed to detect the relative mRNA expression level of C1QTNF1-AS1, miR-221-3p, SOCS3 and key genes in the JAK/STAT signaling pathway in HCC tissues and cells, and western blot analysis was conducted to detect the relative protein expression levels of SOCS3 and key proteins in the JAK/STAT signaling pathway in HCC tissues and cells. MTT assay, transwell assay and flow cytometry were utilized to assess HCC cell proliferation, invasion, migration and apoptosis. Dual luciferase reporter gene assay was used to verify the targeted relationship between C1QTNF1-AS1 and miR-221-3p, as well as between miR-221-3p and SOCS3. A tumorigenicity assay in nude mice was conducted to investigate the effects of C1QTNF1-AS1 on HCC tumor growth in vivo.

RESULTS

C1QTNF1-AS1 and SOCS3 were down-regulated, while miR-221-3p was up-regulated in HCC tissues and cells. In HepG2 and Huh7 cells, overexpression of C1QTNF1-AS1 or SOCS3, as well as silence of miR-221-3p inhibited HCC cell proliferation, migration, and invasion and promoted HCC cell apoptosis. The results of the dual luciferase reporter gene assay indicated that miR-221-3p could directly target both C1QTNF1-AS1 and SOCS3. In addition, up-regulation of C1QTNF1-AS1 suppressed HCC tumor growth in vivo.

CONCLUSION

Overexpression of C1QTNF1-AS1 down-regulated miR-221-3p and subsequently up-regulated SOCS3, thereby inhibiting HCC cell proliferation, migration and invasion and promoting apoptosis through the JAK/STAT signaling pathway.

MicroRNA-221 promotes papillary thyroid carcinoma cell migration and invasion via targeting RECK and regulating epithelial-mesenchymal transition

Aim

The aim of this study was to detect the effects and potential mechanisms of microRNA-221 on a series of biological behaviors of papillary thyroid carcinoma (PTC) cells in vitro and in vivo.

Methods

First, we analyzed the relationship between the expression of miR-221 and several clinicopathological features of PTC patients and then detected the expression of the miR-221 in tumor tissues and cell lines. The effects of miR-221 on proliferation and invasion of PTC cells were verified by cell counting kit-8 (CCK-8) assay, wound healing assay and transwell assay. Western blot assay was applied to explore the correlation between miR-221 and RECK expression in PTC K1 cells. Finally, a xenograft model was established to further confirm the tumor-promoting effects of miR-221 in vivo.

Results

Our data indicated that miR-221 was relatively upregulated in metastatic PTC tissues. MiR-221 promoted the proliferation, migration and invasion activities of PTC K1 cells, following variations of epithelial-mesenchymal transition (EMT)-related protein expression. We identified RECK as a direct target of miR-221, revealed its expression to be inversely correlated with miR-221 in PTC samples and showed that its reintroduction reverses miR-221-induced PTC invasiveness. In addition, miR-221 was also verified to promote tumor growth and increase tumor volume and weight in vivo. Taken together, miR-221/RECK axis could be an effective way to regulate biological behaviors of PTC.

Conclusion

MiR-221 may be involved in PTC cell invasion and metastasis by targeting RECK, indicating that the miR-221/RECK pathway could be studied further as a potential new diagnostic or prognostic biomarker for PTC.

The Network of Non-coding RNAs in Cancer Drug Resistance

Non-coding RNAs (ncRNAs) have been implicated in most cellular functions. The disruption of their function through somatic mutations, genomic imprinting, transcriptional and post-transcriptional regulation, plays an ever-increasing role in cancer development. ncRNAs, including notorious microRNAs, have been thus proposed to function as tumor suppressors or oncogenes, often in a context-dependent fashion. In parallel, ncRNAs with altered expression in cancer have been reported to exert a key role in determining drug sensitivity or restoring drug responsiveness in resistant cells. Acquisition of resistance to anti-cancer drugs is a major hindrance to effective chemotherapy and is one of the most important causes of relapse and mortality in cancer patients. For these reasons, non-coding RNAs have become recent focuses as prognostic agents and modifiers of chemo-sensitivity. This review starts with a brief outline of the role of most studied non-coding RNAs in cancer and then highlights the modulation of cancer drug resistance via known ncRNAs based mechanisms. We identified from literature 388 ncRNA-drugs interactions and analyzed them using an unsupervised approach. Essentially, we performed a network analysis of the non-coding RNAs with direct relations with cancer drugs. Within such a machine-learning framework we detected the most representative ncRNAs-drug associations and groups. We finally discussed the higher integration of the drug-ncRNA clusters with the goal of disentangling effectors from downstream effects and further clarify the involvement of ncRNAs in the cellular mechanisms underlying resistance to cancer treatments.

Pharmacoepigenetics and pharmacoepigenomics of gastrointestinal cancers

Our understanding of the epigenetic changes occurring in gastrointestinal cancers has gained tremendous advancements in recent years, and some epigenetic biomarkers are already translated into the clinics for cancer diagnostics. In parallel, pharmacoepigenetics and pharmacoepigenomics of solid tumors are relevant novel, but emerging and promising fields. Areas covered: A comprehensive review of the literature to summarize and update the emerging field of pharmacoepigenetics and pharmacoepigenomics of gastrointestinal cancers. Expert commentary: Several epigenetic modifications have been proposed to account for interindividual variations in drug response in gastrointestinal cancers. Similarly, single-agent or combined strategies with high doses of drugs that target epigenetic modifications (epi-drugs) were scarcely tolerated by the patients, and current research has moved to their combination with standard therapies to achieve chemosensitization, radiosensitization, and immune modulation of cancerous cells. In parallel, recent genome-wide technologies are revealing the pathways that are epigenetically deregulated during cancer-acquired resistance, including those targeted by non-coding RNAs. Indeed, novel, less toxic, and more specific molecules are under investigation to specifically target those pathways. The field is rapidly expanding and gathering together information coming from these investigations has the potential to lead to clinical applications in the coming new years.

MicroRNA-221-3p is up-regulated and serves as a potential biomarker in pancreatic cancer

It has been demonstrated that circulating MicroRNAs (miRNAs) could be potential biomarkers for cancer diagnosis and prognosis. For pancreatic cancer (PCa), little is known about miR-221-3p biological function or its prognostic value. In the current study, we profiled miR-221-3p expression in PCa cell lines. Compared with normal pancreases ductal epithelial cells, miR-221-3p is up-regulated in all PCa cell lines analysed. In SW1990 cells, overexpression of miR-221-3p increased cell proliferation and inhibited apoptosis, while inhibition of miR-221-3p decreased cell growth rate and promoted apoptosis. Compared with adjacent non-tumour tissues, miR-221-3p was up-regulated in all 21 PCa tissues. Expression level of miR-221-3p was investigated in plasma and statistical analyses showed that circulating miR-221-3p expression level was correlated with distant metastasis and TNM stages. The receiver-operating characteristic (ROC) curves and the area under the ROC curve (AUC) suggested that the diagnostic efficacy for distant metastasis of miR-221-3p is better than CA19-9 (AUC: 0.689 vs. 0.587). To summary, we found miR-221-3p could promote cell proliferation and inhibit apoptosis in PCa cells and circulating miR-221-3p could serve as a biomarker for PCa.

Influence of microRNAs and Long Non-Coding RNAs in Cancer Chemoresistance

Innate and acquired chemoresistance exhibited by most tumours exposed to conventional chemotherapeutic agents account for the majority of relapse cases in cancer patients. Such chemoresistance phenotypes are of a multi-factorial nature from multiple key molecular players. The discovery of the RNA interference pathway in 1998 and the widespread gene regulatory influences exerted by microRNAs (miRNAs) and other non-coding RNAs have certainly expanded the level of intricacy present for the development of any single physiological phenotype, including cancer chemoresistance. This review article focuses on the latest research efforts in identifying and validating specific key molecular players from the two main families of non-coding RNAs, namely miRNAs and long non-coding RNAs (lncRNAs), having direct or indirect influences in the development of cancer drug resistance properties and how such knowledge can be utilised for novel theranostics in oncology.