miR-375 is upregulated in acquired paclitaxel resistance in cervical cancer

Target-induced multiregion MNAzyme nanowires for ultrasensitive homogeneous detection of microRNAs

A target-induced multiregion MNAzyme nanowire system is designed for the ultrasensitive and homogeneous detection of microRNAs (miRNAs). miRNA-21 and miRNA-375 are chosen as analytes, and a miRNA-induced primer exchange reaction (PER) is utilized to construct a long DNA strand with repetitive sequences. This innovative design enables the efficient anchoring of numerous MNAzymes. This unique architecture significantly boosts the effective local concentration of MNAzymes, thereby enhancing the sensitivity and efficiency of miRNA detection. Notably, the limit of detection (LOD) achieved with our target-induced multiregion MNAzyme nanowire approach is over an order of magnitude lower than most other MNAzyme-based methods, while the MNAzyme reaction time is reduced from several hours to 50 min. The method has demonstrated successful applications in quantitatively determining the expression levels of two miRNAs in cell lysates of MCF-7, HeLa and MCF-10 A cells, highlighting its potential for assaying miRNA biomarkers in clinical samples.

Combination of FOLFOXIRI Drugs with Oncolytic Coxsackie B3 Virus PD-H Synergistically Induces Oncolysis in the Refractory Colorectal Cancer Cell Line Colo320

FOLFOXIRI chemotherapy is a first-line therapy for advanced or metastatic colorectal cancer (CRC), yet its therapeutic efficacy remains limited. Immunostimulatory therapies like oncolytic viruses can complement chemotherapies by fostering the infiltration of the tumor by immune cells and enhancing drug cytotoxicity. In this study, we explored the effect of combining the FOLFOXIRI chemotherapeutic agents with the oncolytic coxsackievirus B3 (CVB3) PD-H in the CRC cell line Colo320. Additionally, we examined the impact of the drugs on the expression of microRNAs (miRs), which could be used to increase the safety of oncolytic CVB3 containing corresponding miR target sites (miR-TS). The measurement of cytotoxic activity using the Chou-Talalay combination index approach revealed that PD-H synergistically enhanced the cytotoxic activity of oxaliplatin (OX), 5-fluorouracil (5-FU) and SN-38. PD-H replication was not affected by OX and SN-38 but inhibited by high concentrations of 5-FU. MiR expression levels were not or only slightly elevated by the drugs or with drug/PD-H combinations on Colo320 cells. Moreover, the drug treatment did not increase the mutation rate of the miR-TS inserted into the PD-H genome. The results demonstrate that the combination of FOLFOXIRI drugs and PD-H may be a promising approach to enhance the therapeutic effect of FOLFOXIRI therapy in CRC.

MiRNA in cervical cancer: Diagnosis to therapy: Systematic review

Cancers are one of the most public health problems worldwide. Among them, cervical cancer (CC) is the fourth most prevalent cancer with 604 000 new cases and 342 000 deaths. Mostly, it is associated with Human papillomavirus (HPV). It has been caused by the aggregation of genetic and epigenetic modifications in cervical epithelial cells. Although genetic mutations are given great attention for the carcinogenesis of CC, epigenetic changes have emerged as a hotspot area for CC biomarkers research with great implications for early diagnosis, prognosis, and treatment response prediction of the disease. Recently, there are several studies focused on miRNAs as biomarkers of cervical cancer. However, the precise function of miRNAs in the development of cervical cancer is not still completely understood, particularly when it comes to unconventional sampling materials like cervical mucus and plasma serum. Hence, this review article will give a summary of the miRNAs profiles that emerge at different stages of cervical cancer progression and their downstream effects on target genes and associated signaling pathways. Finally, these results may provide insight into the use of miRNAs as biomarkers for the prediction or diagnosis of cervical cancer or the development of miRNA-based therapeutics against cervical cancer.

Crosstalk between miRNAs and DNA Methylation in Cancer

miRNAs are some of the most well-characterized regulators of gene expression. Integral to several physiological processes, their aberrant expression often drives the pathogenesis of both benign and malignant diseases. Similarly, DNA methylation represents an epigenetic modification influencing transcription and playing a critical role in silencing numerous genes. The silencing of tumor suppressor genes through DNA methylation has been reported in many types of cancer and is associated with tumor development and progression. A growing body of literature has described the crosstalk between DNA methylation and miRNAs as an additional layer in the regulation of gene expression. Methylation in miRNA promoter regions inhibits its transcription, while miRNAs can target transcripts and subsequently regulate the proteins responsible for DNA methylation. Such relationships between miRNA and DNA methylation serve an important regulatory role in several tumor types and highlight a novel avenue for potential therapeutic targets. In this review, we discuss the crosstalk between DNA methylation and miRNA expression in the pathogenesis of cancer and describe how miRNAs influence DNA methylation and, conversely, how methylation impacts the expression of miRNAs. Finally, we address how these epigenetic modifications may be leveraged as biomarkers in cancer.

Advances in epigenetic modifications and cervical cancer research

Cervical cancer (CC) is an important public health problem for women, and perspectives and information regarding its prevention and treatment are quickly evolving. Human papilloma virus (HPV) has been recognized as a major contributor to CC development; however, HPV infection is not the only cause of CC. Epigenetics refers to changes in gene expression levels caused by non-gene sequence changes. Growing evidence suggests that the disruption of gene expression patterns which were governed by epigenetic modifications can result in cancer, autoimmune diseases, and various other maladies. This article mainly reviews the current research status of epigenetic modifications in CC based on four aspects, respectively DNA methylation, histone modification, noncoding RNA regulation and chromatin regulation, and we also discuss their functions and molecular mechanisms in the occurrence and progression of CC. This review provides new ideas for early screening, risk assessment, molecular targeted therapy and prognostic prediction of CC.

miRNAs role in cervical cancer pathogenesis and targeted therapy: Signaling pathways interplay

Cervical cancer (CC) is the primary cause of cancer deaths in underdeveloped countries. The persistence of infection with high-risk human papillomavirus (HPV) is a significant contributor to the development of CC. However, few women with morphologic HPV infection develop invasive illnesses, suggesting other mechanisms contribute to cervical carcinogenesis. MicroRNAs (miRNAs, miRs) are small chain nucleic acids that can regulate wide networks of cellular events. They can inhibit or degrade their target protein-encoding genes. They had the power to regulate CC's invasion, pathophysiology, angiogenesis, apoptosis, proliferation, and cell cycle phases. Further research is required, even though novel methods have been developed for employing miRNAs in the diagnosis, and treatment of CC. We'll go through some of the new findings about miRNAs and their function in CC below. The function of miRNAs in the development of CC and its treatment is one of these. Clinical uses of miRNAs in the analysis, prediction, and management of CC are also covered.

MALAT1-miRNAs network regulate thymidylate synthase and affect 5FU-based chemotherapy

Background

The active metabolite of 5-Fluorouracil (5FU), used in the treatment of several types of cancer, acts by inhibiting the thymidylate synthase encoded by the TYMS gene, which catalyzes the rate-limiting step in DNA replication. The major failure of 5FU-based cancer therapy is the development of drug resistance. High levels of TYMS-encoded protein in cancerous tissues are predictive of poor response to 5FU treatment. Expression of TYMS is regulated by various mechanisms, including involving non-coding RNAs, both miRNAs and long non-coding RNAs (lncRNAs).

Aim

To delineate the miRNAs and lncRNAs network regulating the level of TYMS-encoded protein.

Main body

Several miRNAs targeting TYMS mRNA have been identified in colon cancers, the levels of which can be regulated to varying degrees by lncRNAs. Due to their regulation by the MALAT1 lncRNA, these miRNAs can be divided into three groups: (1) miR-197-3p, miR-203a-3p, miR-375-3p which are downregulated by MALAT1 as confirmed experimentally and the levels of these miRNAs are actually reduced in colon and gastric cancers; (2) miR-140-3p, miR-330-3p that could potentially interact with MALAT1, but not yet supported by experimental results; (3) miR-192-5p, miR-215-5p whose seed sequences do not recognize complementary response elements within MALAT1. Considering the putative MALAT1-miRNAs interaction network, attention is drawn to the potential positive feedback loop causing increased expression of MALAT1 in colon cancer and hepatocellular carcinoma, where YAP1 acts as a transcriptional co-factor which, by binding to the TCF4 transcription factor/ β-catenin complex, may increase the activation of the MALAT1 gene whereas the MALAT1 lncRNA can inhibit miR-375-3p which in turn targets YAP1 mRNA.

Conclusion

The network of non-coding RNAs may reduce the sensitivity of cancer cells to 5FU treatment by upregulating the level of thymidylate synthase.

Resistance to Intervention: Paclitaxel in Breast Cancer

Breast cancer stands as the most prevalent cancer in women globally, and contributes to the highest percentage of mortality due to cancer-related deaths in women. Paclitaxel (PTX) is heavily relied on as a frontline chemotherapy drug in breast cancer treatment, especially in advanced metastatic cancer. Generation of resistance to PTX often derails clinical management and adversely affects patient outcomes. Understanding the molecular mechanism of PTX resistance is necessary to device methods to aid in overcoming the resistance. Recent studies exploring the mechanism of development of PTX resistance have led to unveiling of a range novel therapeutic targets. PTX resistance pathways that involve major regulatory proteins/RNAs like RNF8/Twist/ROR1, TLR, ErbB3/ErbB2, BRCA1- IRIS, MENA, LIN9, MiRNA, FoxM1 and IRAK1 have expanded the complexity of resistance mechanisms, and brought newer insights into the development of drug targets. These resistance-related targets can be dealt with synthetic/natural therapeutics in combination with PTX. The present review encompasses the recent understanding of PTX resistance mechanisms in breast cancer and possible therapeutic combinations to overcome resistance.

Understanding the Molecular Mechanism of miR-877-3p Could Provide Potential Biomarkers and Therapeutic Targets in Squamous Cell Carcinoma of the Cervix

No therapeutic targets and molecular biomarkers are available in cervical cancer (CC) management. In other cancer types, micro-RNA-877-3p (miR-877-3p) has been associated with events relevant for CC development. Thus, we aimed to determine miR-877-3p role in CC. miR-877-3p levels were examined by quantitative-PCR in 117 cervical lesions and tumors. Effects on CC cell proliferation, migration, and invasion were evaluated upon anti-miR-877-3p transfection. miR-877-3p dependent molecular mechanism was comprehensively explored by proteomics, dual-luciferase reporter assay, western blot, and immunohistochemistry. Cervical tumors expressed higher miR-877-3p levels than benign lesions. miR-877-3p promoted CC cell migration and invasion, at least partly by modulating cytoskeletal protein folding through the chaperonin-containing T-complex protein 1 complex. Notably, miR-877-3p silencing synergized with paclitaxel. Interestingly, miR-877-3p downregulated the levels of an in silico-predicted target, ZNF177, whose expression and subcellular location significantly distinguished high-grade squamous intraepithelial lesions (HSILs) and squamous cell carcinomas of the cervix (SCCCs). Cytoplasmic ZNF177 was significantly associated with worse progression-free survival in SCCC. Our results suggest that: (i) miR-877-3p is a potential therapeutic target whose inhibition improves paclitaxel effects; (ii) the expression and location of its target ZNF177 could be diagnostic biomarkers between HSIL and SCCC; and (iii) cytoplasmic ZNF177 is a poor-prognosis biomarker in SCCC.

MicroRNA-34c-3p target inhibiting NOTCH1 suppresses chemosensitivity and metastasis of non-small cell lung cancer

Background

Chemotherapy is the standard treatment for non-small cell lung cancer (NSCLC). However, chemoresistance frequently occurs, making the treatment of NSCLC more difficult.

Method

We combined clinical and experimental studies to establish the role of microRNA (miR)-34c in NSCLC metastasis and chemoresistance.

Results

MiR-34c expression was significantly decreased in patients with NSCLC who showed a poor chemoresponse and metastasis. Overexpression of miR-34c sensitized NSCLC cells to paclitaxel and cisplatin both in vitro and in vivo. Furthermore, we found that NOTCH1 was target of miR-34c in NSCLC cells and played a key role in the effects of miR-34c on NSCLC.

Conclusion

NSCLC metastasis and chemoresistance are suppressed though the miR-34c/NOTCH1 axis. MiR-34c has important implications in the development of therapeutic strategies for metastasis and chemoresistance in NSCLC.

MicroRNA-Based Fingerprinting of Cervical Lesions and Cancer

The regulatory functions of microRNA (miRNA) are involved in all processes contributing to carcinogenesis and response to viral infections. Cervical cancer in most cases is caused by the persistence of high-risk human papillomavirus (HR-HPV) infection. While oncogenic human papillomaviruses induce aberrant expression of many cellular miRNAs, this dysregulation could be harnessed as a marker in early diagnosis of HR-HPV infection, cervical squamous intraepithelial lesions, and cancer. In recent years, growing data indicate that miRNAs show specific patterns at various stages of cervical pathology. The aim of this review is to systematize current reports on miRNA capacity that can be utilized in personalized diagnostics of cervical precancerous and cancerous lesions. The analysis of the resources available in online databases (National Center for Biotechnology Information—NCBI, PubMed, ScienceDirect, Scopus) was performed. To date, no standardized diagnostic algorithm using the miRNA pattern in cervical pathology has been defined. However, the high sensitivity and specificity of the reported assays gives hope for the development of non-invasive diagnostic tests that take into account the heterogeneity of tumor-related changes. Due to this variability resulting in difficult to predict clinical outcomes, precise molecular tools are needed to improve the diagnostic and therapeutic process.

Genomic landscape analyses in cervical carcinoma and consequences for treatment

Where we are on the road to 'tailor-made' precision medicine for drug-resistant cervical carcinoma? We explored studies about analyses of viral and human genomes, epigenomes and transcriptomes, DNA mutation analyses, their importance in detecting HPV sequences, mechanisms of drug resistance to established and targeted therapies with small molecule or therapeutic antibodies, to radiosensitivity and to chemoradiotherapy. The value of repurposing of old drugs initially approved for other disease indications and now considered for cervix cancer therapy is also discussed. The microbiome influences drug response and survival too. HPV genomic integration sites were less significant. Nomograms (Lee et al., 2013) even outperformed FIGO staging regarding prediction of five-year overall survival times. We conclude that there are still many loose threads to be followed up, before coherent conclusions for individualized therapy of drug-resistant cervical carcinoma can be drawn.

Perspectives on the Role of Histone Modification in Breast Cancer Progression and the Advanced Technological Tools to Study Epigenetic Determinants of Metastasis

Metastasis is a complex process that involved in various genetic and epigenetic alterations during the progression of breast cancer. Recent evidences have indicated that the mutation in the genome sequence may not be the key factor for increasing metastatic potential. Epigenetic changes were revealed to be important for metastatic phenotypes transition with the development in understanding the epigenetic basis of breast cancer. Herein, we aim to present the potential epigenetic drivers that induce dysregulation of genes related to breast tumor growth and metastasis, with a particular focus on histone modification including histone acetylation and methylation. The pervasive role of major histone modification enzymes in cancer metastasis such as histone acetyltransferases (HAT), histone deacetylases (HDACs), DNA methyltransferases (DNMTs), and so on are demonstrated and further discussed. In addition, we summarize the recent advances of next-generation sequencing technologies and microfluidic-based devices for enhancing the study of epigenomic landscapes of breast cancer. This feature also introduces several important biotechnologists for identifying robust epigenetic biomarkers and enabling the translation of epigenetic analyses to the clinic. In summary, a comprehensive understanding of epigenetic determinants in metastasis will offer new insights of breast cancer progression and can be achieved in the near future with the development of innovative epigenomic mapping tools.

microRNA-375 released from extracellular vesicles of bone marrow mesenchymal stem cells exerts anti-oncogenic effects against cervical cancer

BACKGROUND

Cervical cancer is the most prevalent gynecological malignancies accompanied by high mortality, where finding a more effective therapeutic option for cervical cancer is necessary. The inhibitory role of microRNAs (miRNAs) derived from the extracellular vesicles (EVs) of the bone marrow mesenchymal stem cells (BMSCs) was analyzed in cervical cancer.

METHODS

Expression of miR-375 was examined by RT-qPCR in cervical cancer cell lines. The targeting relation between miR-375 and maternal embryonic leucine zipper kinase (MELK) was predicted by bioinformatics analysis and verified by dual-luciferase reporter gene assay. Isolated BMSCs were transfected with lentivirus-mediated vectors, followed by EV extraction. The morphology of EVs was then identified using a NanoSight particle size analyzer and transmission electron microscope (TEM). The biological properties of cervical cancer cells were evaluated using Transwell, EdU, and TUNEL assays, respectively. Xenograft tumors in nude mice were observed to assess cervical tumorigenesis in vivo.

RESULTS

Low expression of miR-375 and high expression of MELK were detected in cervical cancer samples. MELK was identified as the target gene of miR-375, which was negatively correlated with miR-375 levels. Overexpression of miR-375 suppressed proliferation, migration, and invasion of cervical cancer cells, but enhanced cell apoptosis by cooperating with downregulated MELK expression. miR-375 transferred from BMSC-derived EVs exerted the same effects on cell biological activities. Xenograft assays in vivo proved that miR-375 from BMSC-derived EVs inhibited tumor growth.

CONCLUSION

The present study highlighted the role of miR-375 from BMSC-derived EVs in suppressing the progression of cervical cancer, which may contribute to the discovery of novel potential biomarkers for cervical cancer therapy.

The roles of microRNA in human cervical cancer

Although a potentially preventable disease, cervical cancer (CC) is the second most commonly diagnosed gynaecological cancer with at least 530,000 new cases annually, and the prognosis with CC is still poor. Studies suggest that aberrant expression of microRNA (miRNA) contributes to the progression of CC. As a group of small non-coding RNA with 18-25 nucleotides, miRNA regulate about one-third of all human genes. They function by repressing translation or inducing mRNA cleavage or degradation, including genes involved in diverse and important cellular processes, including cell cycling, proliferation, differentiation, and apoptosis. Results showed that misexpression of miRNA is closely related to the onset and progression of CC. This review will provide an overview of the function of miRNA in CC and the mechanisms involved in cervical carcinogenesis.

Circ-PRKDC Contributes to 5-Fluorouracil Resistance of Colorectal Cancer Cells by Regulating miR-375/FOXM1 Axis and Wnt/β-Catenin Pathway

Purpose

Diverse circular RNAs (circRNAs) participate in the regulation of drug resistance in human cancers. However, the role of circRNAs in drug resistance in colorectal cancer (CRC) is dismal. In this study, we aimed to explore the effect of circ-PRKDC on 5-fluorouracil (5-FU) resistance in CRC.

Materials and Methods

The levels of circ-PRKDC, microRNA-375 (miR-375) and forkhead box protein M1 (FOXM1) mRNA were determined by quantitative real-time polymerase chain reaction (qRT-PCR). IC₅₀ of 5-FU, cell colony formation ability and invasion were assessed by Cell Counting Kit-8 (CCK-8) assay, colony formation assay and transwell assay, respectively. The protein levels of P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), FOXM1, β-catenin and c-Myc were measured via Western blot assay. The targeting relationship between miR-375 and circ-PRKDC or FOXM1 was investigated by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The effect of circ-PRKDC in vivo was explored by murine xenograft model assay.

Results

Circ-PRKDC was upregulated in 5-FU-resistant CRC tissues and cells. Circ-PRKDC silencing repressed 5-FU resistance, cell colony formation and invasion in 5-FU-resistant CRC cells in vitro and inhibited 5-FU resistance in vivo. MiR-375 was a target of circ-PRKDC and miR-375 inhibition reversed the effects of circ-PRKDC silencing on 5-FU resistance, cell colony formation and invasion. FOXM1 was a direct target gene of miR-375. MiR-375 suppressed 5-FU resistance by targeting FOXM1. Moreover, circ-PRKDC knockdown decreased FOXM1 expression by targeting miR-375. Additionally, circ-PRKDC knockdown impeded wnt/β-catenin pathway by regulating miR-375 and FOXM1.

Conclusion

Circ-PRKDC enhanced 5-FU resistance in CRC by regulating FOXM1/miR-375 axis and wnt/β-catenin pathway.

MicroRNA-375 Targets ATG14 to Inhibit Autophagy and Sensitize Hepatocellular Carcinoma Cells to Sorafenib

Purpose

Sorafenib has revolutionized treatment of hepatocellular carcinoma (HCC), but its efficacy is limited by drug resistance. Autophagy is the process by which cellular components are transported to lysosomes for degradation, which promotes energy production and production of macromolecular precursors. Studies have suggested that the cytoprotective function of autophagy may contribute to chemoresistance or targeted drug resistance in cancer cells. We investigated the effects of miR-375 and autophagy-related protein 14, and their interrelationships, on sorafenib efficacy.

Methods

Cell viability was measured using the MTT assay, and apoptosis was evaluated using flow cytometry. Colony formation assay was performed to determine changes in cell number. Real-time PCR and Western blotting were performed to quantify the expression of key genes and proteins. Immunofluorescence and transmission electron microscopy were used to detect autophagy. Dual-luciferase reporter assays were used to verify a direct target.

Results

We characterized the relationship between sorafenib and autophagy. We showed that inhibition of autophagy enhanced sensitivity of HCC to sorafenib and showed that miR-375 was important in this process. Finally, we showed that miR-375 affected sensitivity of HCC cells to sorafenib through regulation of ATG14.

Conclusion

We showed that miR-375 sensitized HCC cells to sorafenib by blocking sorafenib-induced autophagy. We also showed that ATG14 was a direct autophagy-related target of miR-375. These findings indicated that miR-375-ATG14 was important in the development of sorafenib resistance in HCC.

Exosome mediated miR-155 delivery confers cisplatin chemoresistance in oral cancer cells via epithelial-mesenchymal transition

Cisplatin is used as chemotherapeutic drug for oral squamous cell carcinoma (OSCC). However, OSCC cells develop resistance following long-term cisplatin exposure. Resistance against cisplatin chemo-therapy is accredited to the process of epithelial-to-mesenchymal transition, which in-turn has been linked to tumor-recurrence. miRNA deregulation, a common event in cancer, plays contributory role in chemo-resistance. Exosomes acts as the natural cargo for miRNA and facilitates inter-cell communication in the tumor micro-environment. Hence, exosomal-mediated miRNA transference may play essential role in drug resistance and serve as a target for cancer-therapy. miR-155 upregulation in OSCC has been described, however, its relevance in the observed chemo-resistance is unclear and also, if exosomes have any role in miR-155 regulation remain elusive. In the present study, we document for the first time the critical role of exosomes in mediating increments in miR-155 expression in OSCC cells that have acquired cisplatin resistance (cisRes cells). Importantly, exosomal transfer from cisRes to the cisplatin sensitive (cisSens) cells was found to confer significant miR-155 induction in the recipient cisSens cells. Restoration of miR-155 expression in cisSens cells following miR-155 mimics treatment led to epithelial to mesenchymal transition, enhancements in their migratory potential as well as acquisition of resistant phenotype. Notably, similar augmentations in the migratory and chemo-resistant traits were seen upon delivery of exosomes from cisRes to the recipient cisSens cells. Overall, our findings establish the significance of exosomal-mediated miR-155 shuttling in the cisplatin-chemoresistance, commonly observed in OSCC cells, thereby providing rationale for targeting miR-155 signalling for oral cancer therapy.

MicroRNA-375-3p enhances chemosensitivity to 5-fluorouracil by targeting thymidylate synthase in colorectal cancer

Resistance to chemotherapy is a major challenge for the treatment of patients with colorectal cancer (CRC). Previous studies have found that microRNAs (miRNAs) play key roles in drug resistance; however, the role of miRNA‐373‐3p (miR‐375‐3p) in CRC remains unclear. The current study aimed to explore the potential function of miR‐375‐3p in 5‐fluorouracil (5‐FU) resistance. MicroRNA‐375‐3p was found to be widely downregulated in human CRC cell lines and tissues and to promote the sensitivity of CRC cells to 5‐FU by inducing colon cancer cell apoptosis and cycle arrest and by inhibiting cell growth, migration, and invasion in vitro. Thymidylate synthase (TYMS) was found to be a direct target of miR‐375‐3p, and TYMS knockdown exerted similar effects as miR‐375‐3p overexpression on the CRC cellular response to 5‐FU. Lipid‐coated calcium carbonate nanoparticles (NPs) were designed to cotransport 5‐FU and miR‐375‐3p into cells efficiently and rapidly and to release the drugs in a weakly acidic tumor microenvironment. The therapeutic effect of combined miR‐375 + 5‐FU/NPs was significantly higher than that of the individual treatments in mouse s.c. xenografts derived from HCT116 cells. Our results suggest that restoring miR‐375‐3p levels could be a future novel therapeutic strategy to enhance chemosensitivity to 5‐FU.

miRNAs as Biomarkers in Disease: Latest Findings Regarding Their Role in Diagnosis and Prognosis

MicroRNAs (miRNAs) represent a class of small, non-coding RNAs with the main roles of regulating mRNA through its degradation and adjusting protein levels. In recent years, extraordinary progress has been made in terms of identifying the origin and exact functions of miRNA, focusing on their potential use in both the research and the clinical field. This review aims at improving the current understanding of these molecules and their applicability in the medical field. A thorough analysis of the literature consulting resources available in online databases such as NCBI, PubMed, Medline, ScienceDirect, and UpToDate was performed. There is promising evidence that in spite of the lack of standardized protocols regarding the use of miRNAs in current clinical practice, they constitute a reliable tool for future use. These molecules meet most of the required criteria for being an ideal biomarker, such as accessibility, high specificity, and sensitivity. Despite present limitations, miRNAs as biomarkers for various conditions remain an impressive research field. As current techniques evolve, we anticipate that miRNAs will become a routine approach in the development of personalized patient profiles, thus permitting more specific therapeutic interventions.

Dysregulation of miR-375/AEG-1 Axis by Human Papillomavirus 16/18-E6/E7 Promotes Cellular Proliferation, Migration, and Invasion in Cervical Cancer

Cervical Cancer (CC) is a highly aggressive tumor and is one of the leading causes of cancer-related deaths in women. miR-375 was shown to be significantly down-regulated in cervical cancer cells. However, the precise biological functions of miR-375 and the molecular mechanisms underlying its action in CC are largely unknown. miR-375 targets were predicted by bioinformatics target prediction tools and validated using luciferase reporter assay. Herein, we investigated the functional significance of miR-375 and its target gene in CC to identify potential new therapeutic targets. We found that miR-375 expression was significantly downregulated in CC, and astrocyte elevated gene-1 (AEG-1) was identified as a target of miR-375. Our results also showed that ectopic expression of miR-375 suppressed CC cell proliferation, migration, invasion and angiogenesis, and increased the 5-fluorouracil-induced apoptosis and cell cycle arrest in vitro. In contrast, inhibition of miR-375 expression significantly enhanced these functions. Furthermore, HPV - 16 E6/E7 and HPV - 18 E6/E7 significantly down-regulates miR-375 expression in CC. HPV 16/18-E6/E7/miR-375/AEG-1 axis plays an important role in the regulation of cell proliferation, migration, and invasion in CC. Therefore, targeting miR-375/AEG-1 mediated axis could serve as a potential therapeutic target for CC.

Osthole promotes the suppressive effects of cisplatin on NRF2 expression to prevent drug-resistant cervical cancer progression

Cervical cancer is one of the most commonly diagnosed lethal malignancies among gynecological malignant tumors worldwide. Chemo-resistance is one of the key causal factors in cervical cancer death. Osthole (OST), a natural compound, exhibits various pharmacological activities, including anti-tumor effects. However, its involvement in the chemoresistance of human cervical cancer has not been reported. In the study, we aimed to clarify the role of OST in regulating the chemoresistance of human cervical cancer. The results indicated that cisplatin (CDDP) combined with OST markedly reduced the cell proliferation and induced cervical cancer cells undergoing apoptosis when compared to CDDP alone treatment. In CDDP-resistant cervical cancer cells, OST significantly decreased nuclear factor, erythroid 2 like 2 (NRF2), heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1) and glutamate-cysteine ligase catalytic subunit (GCLC) expression levels from mRNA or protein levels. Additionally, through combination with CDDP, OST dose- and time-dependently reduced NRF2 expression in CDDP-resistant cervical cancer cells. Moreover, we found that CDDP co-treated with OST significantly blocked phosphatidylinositol-3 kinase (PI3K)/AKT signaling pathway. Importantly, CDDP combined with LY294002, inhibitor of phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase (AKT) signaling, markedly decreased the expression of NRF2, HO-1, NQO1 and GCLC in drug-resistant cervical cancer cells. The in vivo study also suggested that OST in combination obviously reduced tumor growth in comparison to the CDDP alone group. Taken together, these findings indicated that OST could be used as a potential sensitizer to reverse chemoresistance of cisplatin-resistant cervical cancer to cisplatin through repressing NRF2 expression partly associated with PI3K/AKT blockage.

Characterization of Hypoxia-associated Molecular Features to Aid Hypoxia-Targeted Therapy

Tumor hypoxia is a major contributor to resistance to anti-cancer therapies. Given that the results of hypoxia-targeted therapy trials have been disappointing, a more personalized approach may be needed. Here we characterize multi-OMIC molecular features associated with tumor hypoxia and identify molecular alterations that correlate with both drug-resistant and drug-sensitive responses to anti-cancer drugs. Based on a well-established hypoxia gene expression signature, we classify about 10,000 tumor samples into hypoxia score-high and score-low groups across different cancer types from The Cancer Genome Atlas and demonstrate their prognostic associations. We then identify various types of molecular features associated with hypoxia status that correlate with drug resistance but, in some cases, also with drug sensitivity, contrasting the conventional view that hypoxia confers drug resistance. We further show that 110 out of 121 (90.9%) clinically actionable genes can be affected by hypoxia status and experimentally validate the predicted effects of hypoxia on the response to several drugs in cultured cells. Our study provides a comprehensive molecular-level understanding of tumor hypoxia and may have practical implications for clinical cancer therapy.

microRNAs: New prognostic, diagnostic, and therapeutic biomarkers in cervical cancer

Cervical cancer is as a kind of cancer beginning from the cervix. Given that cervical cancer could be observed in women who infected with papillomavirus, regular oral contraceptives, and multiple pregnancies. Early detection of cervical cancer is one of the most important aspects of the therapy of this malignancy. Despite several efforts, finding and developing new biomarkers for cervical cancer diagnosis are required. Among various prognostic, diagnostic, and therapeutic biomarkers, miRNA have been emerged as powerful biomarkers for detection, treatment, and monitoring of response to therapy in cervical cancer. Here, we summarized various miRNAs as an employable platform for prognostic, diagnostic, and therapeutic biomarkers in the treatment of cervical cancer.

miR-21, miR-99b and miR-375 combination as predictive response signature for preoperative chemoradiotherapy in rectal cancer

Introduction

Preoperative chemoradiotherapy (CRT) is a standard treatment for locally advanced rectal cancer patients. Despite the benefits of CRT, its use in non-responder patients can be associated with increased toxicities and surgical resection delay. The identification of CRT response biomarkers, such as microRNAs, could improve the management of these patients. We have studied the microRNA expression in pretreatment endoscopy biopsies from rectal cancer patients treated with CRT to identify potential microRNAs able to predict CRT response and clinical outcome of these patients.

Material and methods

RNA from pretreatment endoscopy biopsies from 96 rectal cancer patients treated with preoperative CRT were studied. Pathological response was graded according to the tumor regression grade (TRG) Dworak classification. In the screening phase, 377 miRNAs were studied in 12 patients with extreme responses (TRG0-1 vs TRG4). The potential role as predictive biomarkers for CRT response, disease-free survival (DFS) and overall survival (OS) of the miRNAs identified in the screening phase were validated in the whole cohort.

Results

In the screening phase, an 8-miRNAs CRT-response signature was identified: let-7b, let-7e, miR-21, miR-99b, miR-183, miR-328, miR-375 and miR-483-5p. In the validation phase, miR-21, miR-99b and miR-375 emerged as CRT response-related miRNAs while miR-328 and let-7e emerged as prognostic markers for DFS and OS. Interestingly, ROC curve analysis showed that the combination of miR-21, miR-99b and miR-375 had the best capacity to distinguish patients with maximum response (TRG4) from others.

Conclusions

miR-21, miR-99b and miR-375 could add valuable information for individualizing treatment in locally advanced rectal cancer patients.

The biological functions of target genes in pan-cancers and cell lines were predicted by miR-375 microarray data from GEO database and bioinformatics

BACKGROUND

MicroRNA is endogenous non-coding small RNA that negative regulate and control gene expression, and increasing evidence links microRNA to oncogenesis and the pathogenesis of cancer. The goal of this study was to explore the potential molecular mechanism of miR-375 in various cancers.

METHODS

MiR-375 overexpression in different tumor cell lines was probed with microarray data from Gene Expression Omnibus (GEO). The common target genes of miR-375 were obtained by Robust Rank Aggregation (RRA), and identified by miRWalk2.0 software for target gene prediction. Additionally, we directed in silico analysis including Protein-Protein Interactions (PPI) analysis, gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways annotations to provide a summary of the function of miR-375 in various carcinomas. Eventually, data was obtained from The Cancer Genome Atlas (TCGA) were utilized for a validation in 7 cancers.

RESULTS

The nine miR-375 related chips were acquired by the GEO data. The 5 down regulated genes came from 9 available microarray datasets, which overlapped with the potential target genes predicted by miRWalk2.0 software. The target genes were intensely enriched in amino acid biosynthetic and metabolic process from biological process (GO) and Cysteine and methionine metabolism (KEGG analysis). In view of these approaches, VASN, MAT2B, HERPUD1, TPAPPC6B and TAT are probably the most important miR-375 targets. In addition, miR-375 was negatively correlated with MAT2B, which was verified in 5 tumors of TCGA.

CONCLUSION

In summary, this study based on common target genes provides an innovative perspective for exploring the molecular mechanism of miR-375 in human tumors.

Upregulation of miR-375 inhibits human liver cancer cell growth by modulating cell proliferation and apoptosis via targeting ErbB2

microRNAs (miRNA/miRs) are a class of small non-coding RNAs; they serve important biological roles in tumorigenesis through the regulation of oncogene expression, and they may be used for the diagnosis and treatment of human cancer. miR-375 was identified to exhibit abnormal expression levels in a number of types of tumor; however, the biological role of miR-375 in human hepatocellular carcinoma (HCC) remains incompletely characterized. The present study investigated the expression of miR-375 in human HCC tissues and human liver cancer cell lines; results from a reverse transcription quantitative polymerase chain reaction analysis indicated that the expression of miR-375 was significantly decreased in tissues and live cancer cell lines, compared with normal tissues and PHH cells. Additional studies demonstrated that the upregulation of miR-375 inhibited human liver cancer cell growth via regulation of cell apoptosis. It was also revealed that the receptor tyrosine-protein kinase erbB-2 (ErbB2) gene was a direct target gene of miR-375, and that the regulation of ErbB2 was associated with the human liver cancer growth. Therefore, the present study demonstrated that miR-375 was expressed at low levels both in human HCC tissues and cell line, compared with normal tissues and PHH cells, and that the induction of miR-375 expression may regulate human liver cancer cell function through targeting the ErbB2 gene, which may potentially improve the diagnosis and treatment of patients with HCC in the future.

Combined inhibition of EGFR and c-ABL suppresses the growth of fulvestrant-resistant breast cancer cells through miR-375-autophagy axis

Fulvestrant is the FDA-approved "pure anti-estrogen" agent for malignant breast cancer therapy. But endocrine resistance causes drug failure. A new approach is desired for fulvestrant-resistant breast cancer (FRBC) therapy. This study aims to find an effective approach to inhibit FRBC for patients with advanced breast cancer. MTT assay was first performed to detect the effect of inhibitors of c-ABL (imatinib) and EGFR (lapatinib) on FRBC cells. Microarray analysis was carried out to identify microRNA which is significantly changed between parental and FRBC cells. The related mechanisms were analyzed by qRT-PCR, MTT, AO staining and western blotting. Dual treatment significantly inhibited cell growth of FRBC and upregulated microRNA-375 (miR-375). Overexpression of miR-375 inhibited growth of FRBC cells, reduced autophagy, and decreased expression of ATG7 and LC3-II. Dual treatment elevated expression of miR-375 more than any single one of these two inhibitors. Overexpression of miR-375 increased cell growth inhibition induced by dual treatment, and the effect was attenuated when miR-375 was inhibited. In conclusion, we identified that combined inhibition of EGFR and c-ABL can suppress the growth of FRBC cells and elucidated a mechanism within FRBC cells involving regulation of miR-375 and autophagy. Dual treatment may be useful for inhibiting fulvestrant-resistant breast cancer.

Emblica officinalis extract downregulates pro-angiogenic molecules via upregulation of cellular and exosomal miR-375 in human ovarian cancer cells

Ovarian cancer (OC) is highly resistant to current treatment strategies based on a combination of surgery, chemotherapy and radiation therapy. We have recently demonstrated the anti-neoplastic effect of Amla extract (Emblica officinalis, AE) on OC cells in vitro and in vivo. We hypothesized that AE attenuates growth of OC through microRNA (miR)-regulated mechanism(s). The inhibitory effect of AE on proliferation, migration and invasiveness (P≤0.001) of SKOV3 cells and >90% attenuation of tumor growth in a xenograft mouse model suggested multiple targets. RT-qPCR analysis of microRNAs associated with OC showed a >2,000-fold increase in the expression of miR-375 in AE-treated SKOV3 cells that was blocked by an exogenous miR-375 inhibitor (P≤0.001). AE also decreased the gene and protein expression of IGF1R, a target of miR-375 (P≤0.001), and SNAIL1 (P≤0.002), an EMT-associated transcription factor that represses E-cadherin expression (P≤0.003). AE increased E-cadherin expression (P≤0.001). Treatment of SKOV3 cells with AE resulted in increased miR-375 in exosomes in the medium (P≤0.01). Finally, AE significantly decreased the expression of IGF1R and SNAIL1 proteins during attenuation of SKOV3-derived xenograft tumor. Together, these results show that AE modulates cancer cells and the tumor microenvironment via activation of miR-375 and by targeting IGF1R and SNAIL1 in OC cells.

MicroRNAs in gynecological cancers: Small molecules with big implications

Gynecological cancers (GCs) are often diagnosed at advanced stages, limiting the efficacy of available therapeutic options. Thus, there remains an urgent and unmet need for innovative research for the efficient clinical management of GC patients. Research over past several years has revealed the enormous promise of miRNAs. These small non-coding RNAs can aid in the diagnosis, prognosis and therapy of all major GCs, viz., ovarian cancers, cervical cancers and endometrial cancers. Mechanistic details of the miRNAs-mediated regulation of multiple biological functions are under constant investigation, and a number of miRNAs are now believed to influence growth, proliferation, invasion, metastasis, chemoresistance and the relapse of different GCs. Modulation of tumor microenvironment by miRNAs can possibly explain some of their reported biological effects. miRNA signatures have been proposed as biomarkers for the early detection of GCs, even the various subtypes of individual GCs. miRNA signatures are also being pursued as predictors of response to therapies. This review catalogs the knowledge gained from collective studies, so as to assess the progress made so far. It is time to ponder over the knowledge gained, so that more meaningful pre-clinical and translational studies can be designed to better realize the potential that miRNAs have to offer.

miR-30a-5p enhances paclitaxel sensitivity in non-small cell lung cancer through targeting BCL-2 expression

Lung cancer remains the leading cause of cancer-related death worldwide. Paclitaxel, either as monotherapy or combined with other agents, is the standard treatment for advanced non-small cell lung cancer (NSCLC), the most common type of lung cancer. However, both de novo and acquired resistance against paclitaxel frequently occurs and represents a huge clinical problem. The underlying mechanisms remain poorly characterized. Here, by comparing microRNA (miRNA) expression levels using miRNA arrays, we observed differential expression of miR-30a-5p in two independent lung cancer cell pairs (paclitaxel-resistant vs paclitaxel-sensitive A549 cell lines). Overexpression of miR-30a-5p sensitizes NSCLC cells to paclitaxel both in vitro and in vivo. In addition, miR-30a-5p increases paclitaxel sensitivity by promoting chemotherapy-induced apoptosis via downregulating BCL-2, a key apoptosis regulator. High miR-30a-5p expression is positively correlated with enhanced responsiveness to paclitaxel and predicts a more favorable clinical outcome in NSCLC patients. Moreover, miR-30a-5p expression is negatively correlated with BCL-2 expression in NSCLC tissues. These data indicate that miR-30a-5p may be useful to treat paclitaxel-resistant lung cancer and may also provide a biomarker to predict paclitaxel responsiveness in lung cancer.

KEY MESSAGES

BCL-2 is a novel direct target of miR-30a-5p. miR-30a-5p enhances NSCLC paclitaxel sensitivity in vitro and in vivo. miR-30a-5p sensitizes NSCLC cells to paclitaxel by inducing apoptosis through BCL-2 inhibition. miR-30a-5p negatively correlates with BCL-2 and predicts a favorable clinical outcome in NSCLC patients.

miR-21 inhibitor suppresses cell proliferation and colony formation through regulating the PTEN/AKT pathway and improves paclitaxel sensitivity in cervical cancer cells

The present study aimed to investigate the role and the molecular mechanisms underlying the effects of microRNA-21 (miR-21) on the proliferation, apoptosis and colony formation of cervical cancer cells, and to examine the role of miR-21 in mediating the sensitivity of cervical cancer cells to paclitaxel (PTX). Reverse transcription‑quantitative polymerase chain reaction was employed to determine the level of miR‑21 in various cervical cancer and normal cervical cells. The results revealed that the expression levels of miR-21 in cervical cancer cells were markedly higher when compared with normal cervical cells. Subsequently, a miR‑21 inhibitor or negative control (NC) was transfected into cervical cancer cells. Cell viability, colony formation and apoptosis were then analyzed using an MTT assay, crystal violet and Annexin V-fluorescein isothiocyanate/propidium iodide staining, respectively. The protein expression level of B-cell lymphoma‑2 (Bcl‑2), Bcl‑2‑associated X (Bax), programmed cell death 4 (PDCD4), survivin, c‑myc, phosphatase and tensin homolog (PTEN) and phosphorylated (p)‑AKT were determined by western blot analysis. The sensitivity of cervical cancer cells to PTX (25, 50 and 100 µg/ml) was characterized using an MTT assay. The results demonstrated that the miR-21 inhibitor promoted apoptosis of cervical cancer cells and suppressed their proliferation and colony formation when compared with the NC. In addition, the expression levels of Bcl‑2, survivin, c‑myc and p‑AKT were significantly downregulated in cells transfected with the miR‑21 inhibitor, whilst the expression levels of Bax, PDCD4 and PTEN were significantly upregulated. Furthermore, the miR‑21 inhibitor significantly enhanced the inhibition efficacy of PTX at a range of concentrations in cervical cancer cells. It was concluded that inhibition of miR‑21 suppressed cell proliferation and colony formation through regulating the PTEN/AKT pathway, and improved PTX sensitivity in cervical cancer cells. The results of the present study may contribute to the development of miRNA‑based cervical cancer therapy in the future.

Role of Epigenetics in Uveal Melanoma

Uveal melanoma (UM) is a severe human malignancy with a high mortality rate that demands continued research into new and alternative forms of prevention and treatment. The emerging field of epigenetics is beginning to unfold an era of contemporary approaches to reducing the risk and improving the clinical treatment of UM. Epigenetic changes have a high prevalence rate in cancer, are reversible in nature, and can lead to cancer characteristics even in mutation-free cells. The information contained in this review highlights and expands on the main mechanisms of epigenetic dysregulation in UM tumorigenesis, progression and metastasis, including microRNA expression, hypermethylation of genes and histone modification. Epigenetic drugs have been shown to enhance tumor suppressor gene expression and drug sensitivity in many other cancer cell lines and animal models. An increased understanding of epigenetic mechanisms in UM will be invaluable in the design of more potent epigenetic drugs, which when used in combination with traditional therapies, may permit improved therapeutic outcomes.

Synergism between RIZ1 gene therapy and paclitaxel in SiHa cervical cancer cells

RIZ1 is a tumor suppressor gene. The purpose of the present study was to investigate the inhibitory effect of RIZ1 gene therapy on the growth of SiHa cervical cancer cells and its synergism with paclitaxel. The expression levels of RIZ1 were examined by real-time PCR and western blotting before and after transfection of RIZ1. The effects of paclitaxel or pcDNA3.1(+)-RIZ1 alone or in combination, on the proliferation of SiHa cells were evaluated by MTT method. The inhibitory effect on the proliferation of SiHa cells was more significant in the pcDNA3.1(+)-RIZ1 combined with paclitaxel group than in the pcDNA3.1(+)-RIZ1 or paclitaxel groups (P<0.05). The expression level of RIZ1 in SiHa cells increased after treatment with paclitaxel, which indicated a synergism between them. RIZ1 gene therapy combined with paclitaxel showed stronger cell inhibition than paclitaxel alone, which indicated a synergism between them.

Expression profiles of miR-29c, miR-200b and miR-375 in tumour and tumour-adjacent tissues of head and neck cancers

Altered expression of microRNAs (miRNAs) has been shown in many types of malignancies including the head and neck squamous cell carcinoma (HNSCC). Although there are many new and innovative approaches in the treatment of HNSCC, a clear marker of this disease is still missing. Three candidate miRNAs (miR-29c-3p, miR-200b-5p and miR-375-3p) were studied in connection with HNSCC using quantitative real-time PCR expression levels in 42 tissue samples of HNSCC patients and histologically normal tumour-adjacent tissue samples of these patients. Primary HNSCC carcinoma tissues can be distinguished from histologically normal-matched noncancerous tumour-adjacent tissues based on hsa-miR-375-3p expression (sensitivity 87.5 %, specificity 65 %). Additionally, a significant decrease of hsa-miR-200b-5p expression was revealed in tumour-adjacent tissue samples of patients with node positivity. Lower expression of hsa-miR-200b-5p and hsa-miR-29c-3p in HNSCC tumour tissue was associated with higher tumour grade. Consequently, survival analysis was performed. Lower expression of hsa-miR-29c-3p in tumour-adjacent tissue was associated with worse overall and disease-specific survivals. Lower expression of miR-29c-3p in tumourous tissue was associated with worse relapse-free survival. hsa-miR-375-3p seems to be a relatively promising diagnostic marker in HNSCC but is not suitable for prognosis of patients. Furthermore, this study highlighted the importance of histologically normal tumour-adjacent tissue in HNSCC progress (significant decrease of hsa-miR-200b-5p expression in tumour-adjacent tissue of patients with node positivity and low expression of hsa-miR-29c-3p in HNSCC tumour-adjacent tissue associated with worse prognosis).

Low folate levels are associated with methylation-mediated transcriptional repression of miR-203 and miR-375 during cervical carcinogenesis

The aim of the present study was to investigate the correlation between a lack of folic acid and the abnormal expression of microRNA (miR)-203 and miR-375 in cervical cancer. In total, 60 tissue samples of cervical intraepithelial neoplasia (CIN) or stage IA-IIA cervical cancer (study group), and 30 samples without soluble interleukin or malignancy (control group) were examined. The expression of miR-203 and miR-375 was detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and the difference in expression levels was quantified using the 2^-ΔΔCq method. In addition, CaSki cervical cancer cells were cultured in vitro and treated with various concentrations of folic acid. The DNA methylation states of miR-203 and miR-375 were subsequently detected by methylation-specific PCR, and the expression levels were evaluated using RT-PCR. miR-203 and miR-375 were significantly downregulated in CIN and cervical cancer tissues, compared with the control group. There was a marked difference in terms of the expression levels of miR-375 between the two groups (P<0.05). In CaSki cells, as the concentration of folic acid increased, the positive rate of DNA methylation of miR-203 and miR-375 decreased, while the expression levels of miR-203 and miR-375 demonstrated a gradual increase, which indicated that the latter two parameters were negatively correlated (P<0.05). Compared with normal cervical tissue, the expression levels of miR-203 and miR-375 were downregulated in CIN and cervical cancer. Methylation of these two miRs was apparent in CaSki cells, and was associated with a lack of folic acid. Therefore, reduced levels of folic acid, leading to increased methylation of miR-203 and miR-375, may be significant events during cervical carcinogenesis.

MiR-125a promotes paclitaxel sensitivity in cervical cancer through altering STAT3 expression

Cervical cancer (CC) is one of the most common malignancies in women. Paclitaxel is the front-line chemotherapeutic agent for treating CC. However, its therapeutic efficacy is limited because of chemoresistance, the mechanism of which remains poorly understood. Here, we used microRNA (miRNA) arrays to compare miRNA expression levels in the CC cell lines, HeLa and CaSki, with their paclitaxel resistance counterparts, HeLa/PR and CaSki/PR. We demonstrate that miR-125a was one of most significantly downregulated miRNAs in paclitaxel-resistant cells, which also acquired cisplatin resistance. And that the upregulation of miR-125a sensitized HeLa/PR and CaSki/PR cells to paclitaxel both in vitro and in vivo and to cisplatin in vitro. Moreover, we determined that miR-125a increased paclitaxel and cisplatin sensitivity by downregulating STAT3. MiR-125a enhanced paclitaxel and cisplatin sensitivity by promoting chemotherapy-induced apoptosis. Clinically, miR-125a expression was associated with an increased responsiveness to paclitaxel combined with cisplatin and a more favorable outcome. These data indicate that miR-125a may be a useful method to enable treatment of chemoresistant CC and may also provide a biomarker for predicting paclitaxel and cisplatin responsiveness in CC.

AKT Inhibition Promotes Nonautonomous Cancer Cell Survival

Small molecule inhibitors of AKT (v-akt murine thymoma viral oncogene homolog) signaling are being evaluated in patients with various cancer types, but have so far proven therapeutically disappointing for reasons that remain unclear. Here, we treat cancer cells with subtherapeutic doses of Akti-1/2, an allosteric small molecule AKT inhibitor, in order to experimentally model pharmacologic inhibition of AKT signaling in vitro. We then apply a combined RNA, protein, and metabolite profiling approach to develop an integrated, multiscale, molecular snapshot of this "AKT(low)" cancer cell state. We find that AKT-inhibited cancer cells suppress thousands of mRNA transcripts, and proteins related to the cell cycle, ribosome, and protein translation. Surprisingly, however, these AKT-inhibited cells simultaneously upregulate a host of other proteins and metabolites posttranscriptionally, reflecting activation of their endo-vesiculo-membrane system, secretion of inflammatory proteins, and elaboration of extracellular microvesicles. Importantly, these microvesicles enable rapidly proliferating cancer cells of various types to better withstand different stress conditions, including serum deprivation, hypoxia, or cytotoxic chemotherapy in vitro and xenografting in vivo. These findings suggest a model whereby cancer cells experiencing a partial inhibition of AKT signaling may actually promote the survival of neighbors through non-cell autonomous communication.

MiR-1204 sensitizes nasopharyngeal carcinoma cells to paclitaxel both in vitro and in vivo

Nasopharyngeal carcinoma (NPC) is an endemic tumor with a relatively high incidence in Southern China and Southeast Asia. Paclitaxel combination chemotherapy has been used for treatment of advanced NPC. However, treatment failure often occurs due to development of acquired paclitaxel resistance. In this study, we first established a paclitaxel-resistant CNE-1/Taxol, HNE-2/Taxol and 5-8F/Taxol cell sublines by treating the parental CNE-1, HNE-2 and 5-8F cells with increasing doses of paclitaxel for about 5 months, respectively. Then, microRNA arrays were used to screen differentially expressed miRNAs between the CNE-1/Taxol cells and the parental CNE-1 cells. We found 13 differentially expressed miRNAs, of which miR-1204 was significantly downregulated in the paclitaxel-resistant CNE-1/Taxol cells. We restored miR-1204 expression in the CNE-1/Taxol, HNE-2/Taxol and 5-8F/Taxol cells and found that restoration of miR-1204 re-sensitized the paclitaxel-resistant CNE-1/Taxol, HNE-2/Taxol and 5-8F/Taxol cells to paclitaxel both in vitro. Finally, we demonstrated that restoration of miR-1204 in significantly inhibits tumor growth in vivo. Thus, our study provides important information for the development of targeted gene therapy for reversing paclitaxel resistance in NPC.

miR-130a activates apoptotic signaling through activation of caspase-8 in taxane-resistant prostate cancer cells

BACKGROUND

The acquisition of drug resistance is one of the most malignant phenotypes of cancer and identification of its therapeutic target is a prerequisite for the development of novel therapy. MicroRNAs (miRNAs) have been implicated in various types of cancer and proposed as potential therapeutic targets for patients. In the present study, we aimed to identify miRNA that could serve as a therapeutic target for taxane-resistant prostate cancer.

METHODS

In order to identify miRNAs related to taxane-resistance, miRNA profiling was performed using prostate cancer PC-3 cells and paclitaxel-resistant PC-3 cell lines established from PC-3 cells. Microarray analysis of mRNA expression was also conducted to search for potential target genes of miRNA. Luciferase reporter assay was performed to examine miRNA binding to the 3'-UTR of target genes. The effects of ectopic expression of miRNA on cell growth, tubulin polymerization, drug sensitivity, and apoptotic signaling pathway were investigated in a paclitaxel-resistant PC-3 cell line.

RESULTS

The expression of miR-130a was down-regulated in all paclitaxel-resistant cell lines compared with parental PC-3 cells. Based on mRNA microarray analysis and luciferase reporter assay, we identified SLAIN1 as a direct target gene for miR-130a. Transfection of a miR-130a precursor into a paclitaxel-resistant cell line suppressed cell growth and increased the sensitivity to paclitaxel. Lastly, ectopic expression of miR-130a did not affect the polymerized tubulin level, but activated apoptotic signaling through activation of caspase-8.

CONCLUSIONS

Our results suggested that reduced expression of miR-130a may be involved in the paclitaxel-resistance and that miR-130a could be a therapeutic target for taxane-resistant prostate cancer patients.

MiR-199a-5p and miR-375 affect colon cancer cell sensitivity to cetuximab by targeting PHLPP1

OBJECTIVES

We aimed to analyze the differentially-expressed miRNAs in colon cancer cells in order to identify novel potential biomarkers involved in cancer cell resistance.

DESIGN AND METHODS

We investigated the miRNA expression profile of GEO human colon carcinoma cells, sensitive to the EGFR inhibitor Cetuximab (CTX) and their CTX-resistant counterpart (GEO CR) by using a miRNA chip.

RESULTS

We found 27 upregulated and 10 downregulated miRNAs in GEO CR compared with GEO cells with a fold change ≥ 2. Among the upregulated miRNAs, we focused on miR-199a-5p and miR-375. We report that their enforced expression promotes CTX resistance, whereas their silencing sensitizes to the same drug. The ability of miR-199a-5p and miR-375 to target PHLPP1 (PH domain and leucine-rich repeat protein phosphatase 1), a tumor suppressor that negatively regulates the AKT pathway, accounts, at least in part, for their drug-resistance activity. Indeed, restoration of PHLPP1 increases sensitivity of the GEO cells to CTX and reverts the resistance-promoting effect of miR-199a-5p and miR-375.

CONCLUSION

This study proposes miR-199a-5p and miR-375 as contributors to CTX resistance in colon cancer and suggests a novel approach based on miRNAs as tools for the therapy of this tumor.

β3-tubulin is a good predictor of sensitivity to taxane-based neoadjuvant chemotherapy in primary breast cancer

The objective of this study was to explore the relationship between β3-tubulin expression and sensitivity to taxane-based neoadjuvant chemotherapy in primary breast cancer patients. A total of 48 local advanced breast cancer patients that received taxane-containing neoadjuvant chemotherapy were studied. The levels of β3-tubulin expression were tested by immunohistochemistry before chemotherapy and at the end of cycles 2, 4 and 6. The correlation between the efficacy of the chemotherapy and β3-tubulin expression and changes in β3-tubulin expression over the course of chemotherapy was examined. β3-tubulin protein expression before chemotherapy was significantly and negatively correlated with the response rate. The overall response rate was 31.8 % in the high β3-tubulin expression group, whereas it was 84.6 % in the low β3-tubulin expression group. At the end of cycles 2, 4 and 6 during the treatment course, the average expression rates of β3-tubulin were showed an increasing trend with β3-tubulin expression level at the end of cycle 4 being significantly different from that before chemotherapy. Nine patients that had a low β3-tubulin expression level preneoadjuvant chemotherapy changed to a high β3-tubulin expression level postneoadjuvant chemotherapy, and they had lower response rate than patients with consistent low. In conclusion, β3-tubulin is a good predictor of chemosensitivity to taxane for breast cancer, and the change of its expression level during chemotherapy may be an important cause of secondary resistance to taxane. Detection of β3-tubulin expression before and throughout the chemotherapy will help with selection of the chemotherapy treatment plan.

MiR-218 inhibits HMGB1-mediated autophagy in endometrial carcinoma cells during chemotherapy

Endometrial carcinoma is the most common gynecological malignancy among women worldwide. Although treatment for EC has improved with the introduction of Paclitaxel (Tax) chemotherapy, the majority of patients will develop resistance to the treatment, leading to poor prognosis. One of the causes of chemoresistance is the increased ability to undergo autophagy. In this study, we identified that miR-218 was significantly down-regulated in Tax-resistant EC cells compared to the non-drug resistant cell lines, and overexpression of miR-218 sensitized paclitaxel resistant EC cells to paclitaxel. Moreover, we demonstrated that miR-218 directly binds to the 3'-UTR of HMGB1 gene. HMGB1 was upregulated in paclitaxel resistant EC cells, it mediated autophagy and contributed to chemotherapy resistance in endometrial carcinoma in vitro. HMGB1-mediated autophagy could be suppressed by miR-218 overexpression in Tax resistant EC cells. In summary, we determined the targeting role of miR-218 to HMGB1 and the regulation of miR-218 on the HMGB1-mediated cell autophagy during chemotherapy resistance in endometrial carcinoma cells. These results reveal novel potential role of miR-218 against chemotherapy resistance during the treatment of endometrial carcinoma.

Targeting MYCN IRES in MYCN-amplified neuroblastoma with miR-375 inhibits tumor growth and sensitizes tumor cells to radiation

The MYCN oncogene is amplified in 20% of neuroblastomas, leading to its overexpression at both the mRNA and protein levels. MYCN overexpression is strongly associated with advanced disease stage, rapid tumor progression and a worse prognosis. In the present study, we identified microRNA-375 (miR-375) as a negative regulator of MYCN: enforced expression of miR-375 inhibited MYCN-amplified neuroblastoma in vitro and in vivo. Upon searching the website miRbase for possible miR-375 binding sites within the whole MYCN mRNA, we found that the MYCN 5'-UTR had significant sequence complementarity to miR-375, yet no complementary sequences existed within the MYCN 3'-UTR and coding regions. Enforced overexpression of miR-375 efficiently inhibited MYCN mRNA translation and protein synthesis, via an IRES-dependent mechanism. In athymic nude mouse model with human MYCN-amplified neuroblastoma, MYCN downregulation by miR-375 led to inhibition of tumor cell growth and tumorigenicity. In particular, miR-375-regulated inhibition of MYCN translation was enhanced when MYCN-amplified neuroblastoma cells were exposed to stress stimulation, such as ionizing irradiation (IR), resulting in a remarkable increase in the neuroblastoma's sensitivity to IR-induced cell death. Our results identified a novel mechanism by which IRES-dependent translation of MYCN is repressed by miR-375, particularly during cellular stress, highlighting a potential anticancer strategy: the development of miR-375 as a novel therapeutic agent to treat MYCN-amplified neuroblastoma.

The combined serum levels of miR-375 and urokinase plasminogen activator receptor are suggested as diagnostic and prognostic biomarkers in prostate cancer

This study aimed to assess the applicability of miR-375 in combination with the soluble urokinase plasminogen activator receptor (suPAR) protein as a diagnostic and/or prognostic biomarker for prostate cancer (PCa) patients. miR-375 levels by qRT-PCR and suPAR levels by ELISA were evaluated in serum samples from 146 PCa patients, 35 benign prostate hyperplasia (BPH) patients and 18 healthy controls. Antigen levels of suPAR differed between healthy controls and PCa or BPH patients, whereas miR-375 levels differed between PCa and BPH patients or healthy controls (p < 0.001). Additionally, suPAR levels differed between the Gleason sum groups GS = 7 versus GS > 7, with higher levels in the latter group (p = 0.011), and miR-375 levels were higher in the tumor stage group T3-T4 compared with the T1-T2 group (p = 0.039). A high concentration of suPAR was associated with a poor disease-specific survival (DSS; p = 0.039). The combination of suPAR and miR-375 levels identified a patient group possessing high levels for both parameters. This was associated with a poorer 10-year overall survival (OS) and DSS, with a 6.38-fold increased risk of death and a 7.68-fold increased risk of tumor-related death (p = 0.00026 and p = 0.014; univariate Cox's regression analysis). In a multivariate Cox's regression analysis PCa patients with high levels of suPAR and miR-375 showed a 5.72-fold increased risk of death in OS (p = 0.006). In summary, the differences between the PCa/BPH/healthy control cohorts for either suPAR and miR-375 levels in conjunction with the association of combined high suPAR/miR-375 levels with a poor prognosis suggest a diagnostic and prognostic impact for PCa patients.