miR-204-5p in vivo inhibition cause diminished CD45RO cells rate in lungs of melanoma B16-bearing mice.

The treatment of melanoma remains a challenge, despite novel approaches recently becoming available for disseminated tumors. RNA targeting is being intensively studied in various types of disease. The aim of the present study was to explore whether the in vivo use of a microRNA (miR)-204-5p inhibitor affected melanoma progression, and whether its metastasis affects target organ remodeling. CD45RO+, CD3+, CD8+, forkhead box P3+, smooth muscle α-actin+ cells in the lungs of B16 melanoma-bearing mice were evaluated using immunohistochemistry following miR-204-5p inhibitor transfection. Next, CD45RO expression in peripheral blood mononuclear cells (PBMCs), as well as the apoptosis of these cells, were measured by flow cytometry. The results revealed that the number of CD45RO+ cells was decreased in the lungs of B16 melanoma-bearing mice and CD45RO+ PBMCs following the use of an miR-204-5p inhibitor, which was associated with increased levels of PBMC apoptosis. In conclusion, the findings of the present study suggested that targeting miR-204-5p in melanoma metastasis target organs could be used to develop novel approaches for the treatment of disseminated forms of the disease.

Semaphorin-5A downregulation is associated with enhanced migration and invasion of BRAF-positive melanoma cells under vemurafenib treatment in melanomas with heterogeneous BRAF status.

Tumor heterogeneity affects the efficacy of anticancer treatment as tumor subclones with distinct molecular patterns may be present within one tumor, leading to differing sensitivities to chemotherapeutic agents. In the present study, six melanoma tissue fragments were obtained from different parts of tumor of four patients and then the effect of vemurafenib treatment on biological characteristics and molecular processes of cell cultures was estimated by using MTT-test, apoptosis, migration and invasion assays, PCR real time. There was different BRAF status determined between cells derived from the central and peripheral regions of primary melanoma tumors. BRAF-positive melanoma cells showed an increased apoptotic rate under vemurafenib treatment, as well as increased migration and invasion rates, whereas BRAF-negative melanoma cells did not exhibit such tendency. Furthermore, semaphorin-5A levels were diminished in BRAF-positive cells, but not in BRAF-negative ones, which could be related to increased migration and invasion. Melanoma cells derived from different regions of the same tumor may differ by mutations status, molecular processes and biological response to target therapy. The downregulation of semaphorin-5A may be involved in divergent effects of anticancer agents on tumor cell biology.