Noncoding RNAs in Therapeutic Resistance of Cancer

circ_0002060 Enhances Doxorubicin Resistance in Osteosarcoma by Regulating the miR-198/ABCB1 Axis

Background: Osteosarcoma (OS) is a common, aggressive primary sarcoma of bone. Drug resistance is a huge obstacle to chemotherapy for cancer. This study aimed to investigate the role and mechanism of circ_0002060 in OS resistance to doxorubicin (DOX). Methods: The levels of circ_0002060, miR-198, and ATP-binding cassette subfamily B member 1 (ABCB1) in OS tissues and DOX-resistant OS cells were measured by quantitative real-time polymerase chain reaction or Western blot assay. Kaplan-Meier analysis was performed to determine the relationship between circ_0002060 expression in OS tissues and overall survival of OS patients. The half-inhibitory concentration (IC50) of DOX was calculated using the Cell Counting Kit-8 (CCK-8) assay. Proliferation and apoptosis of DOX-resistant OS cells were assessed by colony formation assay and flow cytometry. The levels of apoptosis-related proteins in DOX-resistant OS cells were measured by Western blot assay. Xenograft assay was utilized to analyze the effect of circ_0002060 on DOX resistance in vivo. The interactions among circ_0002060, miR-198, and ABCB1 in DOX-resistant OS cells were confirmed by dual-luciferase reporter assay, RNA immunoprecipitation assay, or RNA pull-down assay. Results: circ_0002060 and ABCB1 were upregulated, while miR-198 was downregulated in OS tissues and DOX-resistant OS cells. circ_0002060 silencing reduced DOX resistance in vitro and in vivo. Moreover, circ_0002060 enhanced DOX resistance by sponging miR-198. Besides, miR-198 decreased DOX resistance by binding to ABCB1. In addition, circ_0002060 sponged miR-198 to upregulate ABCB1 expression. Conclusions: circ_0002060 promoted DOX resistance and OS progression by regulating the miR-198/ABCB1 axis, suggesting that circ_0002060 might be a promising biomarker for OS therapy.

Long Noncoding RNAs as Innovative Urinary Diagnostic Biomarkers

The characterization of circulating tumor cells (CTCs) is now widely studied as a promising source of cancer-derived biomarkers because of their role in tumor formation and progression. However, CTCs analysis presents some limitations and no standardized method for CTCs isolation from urine has been defined so far. In fact, besides blood, urine represents an ideal source of noninvasive biomarkers, especially for the early detection of genitourinary tumors. Besides CTCs, long noncoding RNAs (lncRNAs) have also been proposed as potential noninvasive biomarkers, and the evaluation of the diagnostic accuracy of urinary lncRNAs has dramatically increased over the last years, with many studies being published. Therefore, this review provides an update on the clinical utility of urinary lncRNAs as novel biomarkers for the diagnosis of bladder and prostate cancers.

Non coding RNAs as the critical factors in chemo resistance of bladder tumor cells

BACKGROUND

Bladder cancer (BCa) is the ninth frequent and 13th leading cause of cancer related deaths in the world which is mainly observed among men. There is a declining mortality rates in developed countries. Although, the majority of BCa patients present Non-Muscle-Invasive Bladder Cancer (NMIBC) tumors, only 30% of patients suffer from muscle invasion and distant metastases. Radical cystoprostatectomy, radiation, and chemotherapy have proven to be efficient in metastatic tumors. However, tumor relapse is observed in a noticeable ratio of patients following the chemotherapeutic treatment. Non-coding RNAs (ncRNAs) are important factors during tumor progression and chemo resistance which can be used as diagnostic and prognostic biomarkers of BCa.

MAIN BODY

In present review we summarized all of the lncRNAs and miRNAs associated with chemotherapeutic resistance in bladder tumor cells.

CONCLUSIONS

This review paves the way of introducing a prognostic panel of ncRNAs for the BCa patients which can be useful to select a proper drug based on the lncRNA profiles of patients to reduce the cytotoxic effects of chemotherapy in such patients.

Beyond MicroRNAs: Emerging Role of Other Non-Coding RNAs in HPV-Driven Cancers

Persistent infection with high-risk Human Papilloma Virus (HPV) leads to the development of several tumors, including cervical, oropharyngeal, and anogenital squamous cell carcinoma. In the last years, the use of high-throughput sequencing technologies has revealed a number of non-coding RNA (ncRNAs), distinct from micro RNAs (miRNAs), that are deregulated in HPV-driven cancers, thus suggesting that HPV infection may affect their expression. However, since the knowledge of ncRNAs is still limited, a better understanding of ncRNAs biology, biogenesis, and function may be challenging for improving the diagnosis of HPV infection or progression, and for monitoring the response to therapy of patients affected by HPV-driven tumors. In addition, to establish a ncRNAs expression profile may be instrumental for developing more effective therapeutic strategies for the treatment of HPV-associated lesions and cancers. Therefore, this review will address novel classes of ncRNAs that have recently started to draw increasing attention in HPV-driven tumors, with a particular focus on ncRNAs that have been identified as a direct target of HPV oncoproteins.

Tumor microenvironment and noncoding RNAs as co-drivers of epithelial-mesenchymal transition and cancer metastasis

Reciprocal interactions between cancer cells and tumor microenvironment (TME) are crucial events in tumor progression and metastasis. Pervasive stromal reprogramming of TME modifies numerous cellular functions, including extracellular matrix (ECM) stiffness, inflammation, and immunity. These environmental factors allow selection of more aggressive cells that develop adaptive strategies associating plasticity and epithelial-mesenchymal transition (EMT), stem-like phenotype, invasion, immunosuppression, and resistance to therapies. EMT is a morphomolecular process that endows epithelial tumor cells with mesenchymal properties, including reduced adhesion and increased motility. Numerous studies have demonstrated involvement of noncoding RNAs (ncRNAs), such as miRNAs and lncRNAs, in tumor initiation, progression, and metastasis. NcRNAs regulate every hallmark of cancer and have now emerged as new players in induction and regulation of EMT. The reciprocal regulatory interactions between ncRNAs, TME components, and cancer cells increase the complexity of gene expression and protein translation in cancer. Thus, deeper understanding of molecular mechanisms controlling EMT will not only shed light on metastatic processes of cancer cells, but enhance development of new therapies targeting metastasis. In this review, we will provide recent findings on the role of known ncRNAs relevant to EMT and cancer metastasis and discuss the role of the interaction between ncRNAs and TME as co-drivers of EMT. Developmental Dynamics 247:405-431, 2018. © 2017 Wiley Periodicals, Inc.