Circulating miRNAs as Diagnostic and Prognostic Biomarkers in Common Solid Tumors: Focus on Lung, Breast, Prostate Cancers, and Osteosarcoma

Long noncoding RNA OIP5-AS1 mediates resistance to doxorubicin by regulating miR-137-3p/PTN axis in osteosarcoma

Opa-interacting protein 5 antisense RNA1 (OIP5-AS1) has been demonstrated to facilitate proliferation, metastasis and resistance to treatments in various types of cancers. Nevertheless, the exact mechanisms underlying the roles of OIP5-AS1 in osteosarcoma(OS) drug resistance have not yet been clearly elucidated. Therefore, we sought to investigate the functional involvement of OIP5-AS1 in osteosarcoma. Our results indicated that OIP5-AS1 was dramatically up-regulated in osteosarcoma drug-resistant tissues and cells in comparison with drug-sensitive tissues and cells. Also, the knockdown of OIP5-AS1 was found to have decreased doxorubicin resistance of OS cells. Further analyses revealed that OIP5-AS1 operated as a competitor for endogenous RNA of miR-137-3p as well as regulated pleiotrophin(PTN) expression, which has been reported to be an oncogene in OS in previous research. Furthermore, the loss of miR-137-3p or alternatively, the gain of PTN, both resulted in the abolishment of the inhibitory role of OIP5-AS1 silencing the proliferative activity. Our analyses indicated and helped to determine the role of OIP5-AS1 in contributing to tumorigenesis of osteosarcoma via the miR-137-3p/PTN axis and, therefore outlining its potential for use as a therapeutic target against this cancer.

microRNAs in the Antitumor Immune Response and in Bone Metastasis of Breast Cancer: From Biological Mechanisms to Therapeutics

Breast cancer is the most common type of cancer in women, and the occurrence of metastasis drastically worsens the prognosis and reduces overall survival. Understanding the biological mechanisms that regulate the transformation of malignant cells, the consequent metastatic transformation, and the immune surveillance in the tumor progression would contribute to the development of more effective and targeted treatments. In this context, microRNAs (miRNAs) have proven to be key regulators of the tumor-immune cells crosstalk for the hijack of the immunosurveillance to promote tumor cells immune escape and cancer progression, as well as modulators of the metastasis formation process, ranging from the preparation of the metastatic site to the transformation into the migrating phenotype of tumor cells. In particular, their deregulated expression has been linked to the aberrant expression of oncogenes and tumor suppressor genes to promote tumorigenesis. This review aims at summarizing the role and functions of miRNAs involved in antitumor immune response and in the metastasis formation process in breast cancer. Additionally, miRNAs are promising targets for gene therapy as their modulation has the potential to support or inhibit specific mechanisms to negatively affect tumorigenesis. With this perspective, the most recent strategies developed for miRNA-based therapeutics are illustrated.

The Clinical Potential of Circulating miRNAs as Biomarkers: Present and Future Applications for Diagnosis and Prognosis of Age-Associated Bone Diseases

Osteoporosis, related fracture/fragility, and osteoarthritis are age-related pathologies that, over recent years, have seen increasing incidence and prevalence due to population ageing. The diagnostic approaches to these pathologies suffer from limited sensitivity and specificity, also in monitoring the disease progression or treatment. For this reason, new biomarkers are desirable for improving the management of osteoporosis and osteoarthritis patients. The non-coding RNAs, called miRNAs, are key post-transcriptional factors in bone homeostasis, and promising circulating biomarkers for pathological conditions in which to perform a biopsy can be problematic. In fact, miRNAs can easily be detected in biological fluids (i.e., blood, serum, plasma) using methods with elevated sensitivity and specificity (RT-qPCR, microarray, and NGS). However, the analytical phases required for miRNAs' evaluation still present some practical issues that limit their use in clinical practice. This review reveals miRNAs' potential as circulating biomarkers for evaluating predisposition, diagnosis, and prognosis of osteoporosis (postmenopausal or idiopathic), bone fracture/fragility, and osteoarthritis, with a focus on pre-analytical, analytical, and post-analytical protocols used for their validation and thus on their clinical applicability. These evidences may support the definition of early diagnostic tools based on circulating miRNAs for bone diseases and osteoarthritis as well as for monitoring the effects of specific treatments.

Role of miRNAs in prostate cancer: Do we really know everything?

Many different genetic alterations, as well as complex epigenetic interactions, are the basis of the genesis and progression of prostate cancer (CaP). This is the reason why until now the molecular pathways related to development of this cancer were only partly known, and even less those that determine aggressive or indolent tumour behaviour. MicroRNAs (miRNAs) represent a class of about 22 nucleotides long, small non-coding RNAs, which are involved in gene expression regulation at the post-transcriptional level. MiRNAs play a crucial role in regulating several biological functions and preserving homeostasis, as they carry out a wide modulatory activity on various molecular signalling pathways. MiRNA genes are placed in cancer-related genomic regions or in fragile sites, and they have been proven to be involved in the main steps of carcinogenesis as oncogenes or oncosuppressors in many types of cancer, including CaP. We performed a narrative review to describe the relationship between miRNAs and the crucial steps of development and progression of CaP. The aims of this study were to improve the knowledge regarding the mechanisms underlying miRNA expression and their target genes, and to contribute to understanding the relationship between miRNA expression profiles and CaP.

Identification of Circulating MicroRNAs as a Promising Diagnostic Biomarker for Cervical Intraepithelial Neoplasia and Early Cancer: A Meta-Analysis

Background

Cervical cancer (CC) is one of the most common female malignant tumors. And cervical intraepithelial neoplasia (CIN) is the precancerous lesion of CC, which can progress to invasive CC. MicroRNAs (miRNAs) have been found to be potential diagnostic biomarkers for CIN or CC. However, recently, the lack of sufficient studies about the diagnostic value of miRNAs for CIN made it challenging to separately investigate the diagnostic efficacy of miRNAs for CIN. Likewise, the conclusions among those studies were discordant. Therefore, we conducted this meta-analysis, aimed at evaluating the diagnostic efficacy of miRNAs for CIN and CC patients.

Methods

Literature search was performed in PubMed, Embase, and Web of Science databases. Pooled sensitivity, specificity, and other diagnostic parameters were calculated through Stata 14.0 software. Furthermore, subgroup analyses and metaregression analysis were conducted to explore the main sources of heterogeneity.

Results

Ten articles covering 50 studies were eligible, which included 5,908 patients and 4,819 healthy individuals. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were 0.81 (95% CI, 0.77-0.85), 0.86 (95% CI, 0.83-0.89), 5.9 (95% CI, 4.5-7.7), 0.22 (95% CI, 0.17-0.28), 27 (95% CI, 17-44), and 0.91 (95% CI, 0.88-0.93), respectively. Additionally, the ethnicity and internal reference were the main sources of heterogeneity.

Conclusions

Circulating miRNAs can be a promising noninvasive diagnostic biomarker for CIN and early CC, especially miR-9 and miR-205, which need to be verified by large-scale studies.