Malignant Pleural Mesothelioma: State-of-the-Art on Current Therapies and Promises for the Future

Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer of the pleural surface associated with asbestos exposure. The median survival of MPM patients is a mere 8-14 months, and there are few biomarkers and no cure available. It is hoped that, eventually, the incidence of MPM will drop and remain low and constant, given that most nations have banned the use of asbestos, but in the meantime, the incidence in Europe is still growing. The exact molecular mechanisms that explain the carcinogenicity of asbestos are not known. Standard therapeutic strategies for MPM include surgery, often coupled with chemotherapy and/or radiotherapy, in a small percentage of eligible patients and chemotherapy in tumors considered unresectable with or without adjuvant radiotherapy. In recent years, several new therapeutic avenues are being explored. These include angiogenesis inhibitors, synthetic lethal treatment, miRNA replacement, oncoviral therapies, and the fast-growing field of immunotherapy alone or in combination with chemotherapy. Of particular promise are the multiple options offered by immunotherapy: immune checkpoint inhibitors, tumor vaccines, and therapies taking advantage of tumor-specific antigens, such as specific therapeutic antibodies or advanced cell-based therapies exemplified by the CAR-T cells. This review comprehensively presents both old and new therapeutic options in MPM, focusing on the results of the numerous recent and on-going clinical trials in the field, including the latest data presented at international meetings (AACR, ASCO, and ESMO) this year, and concludes that more work has to be done in the framework of tailored therapies to identify reliable targets and novel biomarkers to impact MPM management.

Exploring the MIR143-UPAR Axis for the Inhibition of Human Prostate Cancer Cells In Vitro and In Vivo

MIR143 is pathologically downregulated and may function as a tumor suppressor in prostate cancer. Likewise, the urokinase plasminogen activator receptor (UPAR) is overexpressed in prostate carcinoma, representing a negative prognostic marker and putative therapeutic target gene. In this paper, we establish UPAR as a new direct target of MIR143. Luciferase reporter gene constructs identify one of the two in silico-predicted binding sites as functionally relevant for direct MIR143 binding to the 3′ UTR, and, concomitantly, transfection of MIR143 reduces UPAR protein levels in prostate carcinoma cells in vitro. Inhibitory effects on cell proliferation and colony formation, spheroid growth and integrity, and cell viability are extensively analyzed, and they are compared to direct small interfering RNA (siRNA)-mediated uPAR knockdown or combined microRNA (miRNA)-siRNA treatment. Switching to a therapeutically more relevant in vivo model, we demonstrate tumor-inhibitory effects of MIR143 replacement therapy by systemic treatment of mice bearing subcutaneous PC-3 tumor xenografts with MIR143 formulated in polymeric nanoparticles. This efficient, nanoparticle-mediated delivery of intact MIR143 mediates the marked downregulation of uPAR protein, but not mRNA levels, thus indicating translational inhibition rather than mRNA degradation. In summary, we identify UPAR as a direct target gene of MIR143, and we establish the therapeutic anti-tumor potential of nanoparticle-based MIR143 replacement in prostate cancer.

MicroRNA replacement therapy in cancer

Despite the recent progress in cancer management approaches, the mortality rate of cancer is still growing and there are lots of challenges in the clinics in terms of novel therapeutics. MicroRNAs (miRNA) are regulatory small noncoding RNAs and are already confirmed to have a great role in regulating gene expression level by targeting multiple molecules that affect cell physiology and disease development. Recently, miRNAs have been introduced as promising therapeutic targets for cancer treatment. Regulatory potential of tumor suppressor miRNAs, which enables regulation of entire signaling networks within the cells, makes them an interesting option for developing cancer therapeutics. In this regard, over recent decades, scientists have aimed at developing powerful and safe targeting approaches to restore these suppressive miRNAs in cancerous cells. The present review summarizes the function of miRNAs in tumor development and presents recent findings on how miRNAs have served as therapeutic agents against cancer, with a special focus on tumor suppressor miRNAs (mimics). Moreover, the latest investigations on the therapeutic strategies of miRNA delivery have been presented.

Functional Analysis of microRNA in Multiple Myeloma

MicroRNAs (miRNAs) are short non coding RNAs that regulate the gene expression and play a relevant role in physiopathological mechanisms such as development, proliferation, death, and differentiation of normal and cancer cells. Recently, abnormal expression of miRNAs has been reported in most of solid or hematopoietic malignancies, including multiple myeloma (MM), where miRNAs have been found deeply dysregulated and act as oncogenes or tumor suppressors. Presently, the most recognized approach for definition of miRNA portraits is based on microarray profiling analysis. We here describe a workflow based on the identification of dysregulated miRNAs in plasma cells from MM patients based on Affymetrix technology. We describe how it is possible to search miRNA putative targets performing whole gene expression profile on MM cell lines transfected with miRNA mimics or inhibitors followed by luciferase reporter assay to analyze the specific targeting of the 3'untranslated region (UTR) sequence of a mRNA by selected miRNAs. These technological approaches are suitable strategies for the identification of relevant druggable targets in MM.

miR-34 - a microRNA replacement therapy is headed to the clinic

MicroRNA-34 (miR-34) is a master regulator of tumor suppression. It is downregulated in numerous cancers and inhibits malignant growth by repressing genes involved in various oncogenic signaling pathways. Consequently, miR-34 antagonizes processes that are necessary for basic cancer cell viability as well as cancer stemness, metastasis, and chemoresistance. This broad anti-oncogenic activity holds the prospect of creating a new remedy that is effective against tumor heterogeneity. This review focuses on the molecular mechanisms of miR-34-mediated tumor suppression, pharmacologies in animal models of cancer, and a status update of a miR-34 therapy that may be among the first miRNA mimics to reach the clinic.