The development of immunotherapy has improved the treatment of melanoma; however, resistance and frequent recurrence persist and remain a major problem. N6-methyladenosine (m6A) is the most abundant epitranscriptomic mark on mRNA and is essential for various physiological processes; however, its role in melanoma is unknown. Utilizing human normal melanocyte and melanoma cell lines, we analyzed the expression of METTL3 by quantitative RT-PCR. We inhibited the METTL3 expression by shRNA and analyzed the effects on melanoma cell proliferation, colony formation ability, and invasion. Finally, we assessed the role of METTL3 by using wild-type and m6A catalytic site mutant METTL3. Melanoma cell lines express higher levels of METTL3, as compared with normal melanocytes. Interestingly, silencing of METTL3 gene expression in melanoma cells resulted in decreased m6A activity, colony formation and invasiveness, while its overexpression led to increased m6A activity, colony formation and invasion. METTL3 overexpression promotes accumulation of MMP2 and N-cadherin in melanoma cells. Strikingly, the overexpression of m6A catalytic site mutant METTL3 was unable to produce a similar increase in MMP2 expression, suggesting that m6A activity of METTL3 is important for melanoma cell invasiveness. Our results for the first time uncover the role of m6A modification in melanoma cell biology. We show that METTL3 is upregulated in human melanoma and plays a role in invasion/migration through MMP2. These findings provide the framework for the development and use of METTL3 inhibitors in melanoma treatment.

For the treatment of diseases affecting bones using bone regenerative medicine, there is an urgent need to develop safe, inexpensive drugs that can strongly induce bone formation. In the present study, we systematically investigated the effects of icaritin, a metabolic product of icariin, on the osteogenic differentiation of human bone marrow‑derived mesenchymal stem cells (hBMSCs) and human adipose tissue‑derived stem cells (hADSCs) in vitro. After treatment with icaritin at concentrations of 10‑8-10‑5 M, hBMSCs and hADSCs were examined for alkaline phosphatase activity, osteocalcin (OC) secretion, matrix mineralization and expression levels of bone‑related mRNA and proteins. Data showed that icaritin at concentrations 10‑7-10‑5 M significantly increased alkaline phosphatase activity, OC secretion at different time points, and calcium deposition at day 21. In addition, icaritin upregulated the mRNA expression of genes for bone morphogenetic proteins (BMP‑2, ‑4 and ‑7), bone transcription factors (Runx2 and Dlx5) and bone matrix proteins (ALP, OC and Col‑1). Moreover, icaritin increased the protein levels of BMPs, Runx2 and OC, as detected by western blot analysis. These findings suggest that icaritin enhances the osteogenic differentiation of hBMSCS and hADSCs. Icaritin exerts its potent osteogenic effect possibly by directly stimulating the production of BMPs. Although the osteogenic activity of icaritin in vitro was inferior to that of rhBMP‑2, icaritin displayed better results than icariin. Moreover, the low cost, simple extraction procedure, and an abundance of icaritin make it appealing as a bone regenerative medicine.

Tumor-associated macrophages (TAMs) are recognized as a hallmark of certain solid cancers and predictors of poor prognosis; however, the functional role of TAMs in lymphoid malignancies, including B-cell lymphoma, has not been well defined. We identified infiltration of F4/80+ TAMs in a syngeneic mouse model using the recently generated murine mantle cell lymphoma (MCL) cell line FC-muMCL1. Multicolor flow cytometric analysis of syngeneic lymphoma tumors showed distinct polarization of F4/80+ TAMs into CD206+ M2 and CD80+ M1 phenotypes. Using human MCL cell lines (Mino, Granta, and JVM2), we further showed that MCL cells polarized monocyte-derived macrophages toward an M2-like phenotype, as assessed by CD163+ expression and increased interleukin-10 (IL-10) level; however, levels of the M1 markers CD80 and IL-12 remained unaffected. To show that macrophages contribute to MCL tumorigenesis, we xenografted the human MCL cell line Mino along with CD14+ monocytes and compared tumor growth between these 2 groups. Results showed that xenografted Mino along with CD14+ monocytes significantly increased the tumor growth in vivo compared with MCL cells alone (P < .001), whereas treatment with liposomal clodronate (to deplete the macrophages) reversed the effect of CD14+ monocytes on growth of MCL xenografts (P < .001). Mechanistically, IL-10 secreted by MCL-polarized M2-like macrophages was found to be responsible for increasing MCL growth by activating STAT1 signaling, whereas IL-10 neutralizing antibody or STAT1 inhibition by fludarabine or STAT1 short hairpin RNA significantly abolished MCL growth (P < .01). Collectively, our data show the existence of a tumor microenvironmental network of macrophages and MCL tumor and suggest the importance of macrophages in interventional therapeutic strategies against MCL and other lymphoid malignancies.

Atherosclerosis is the leading cause of heart disease and stroke, and one of the leading causes of death and disability worldwide. The phenotypic transformation of vascular smooth muscle cells (VSMCs) plays an important role in the pathological process of atherosclerosis. The present study aimed to identify differently expressed mRNAs in atherosclerosis by analyzing GSE6088 database. Our results revealed there were totally 467 increased and 490 decreased differential expressed genes (DEGs) in atherosclerosis. Bioinformatics analysis demonstrated that the DEGs substantially existed in pathways, including Glyoxylate and dicarboxylate metabolism, Tyrosine metabolism, Tryptophan metabolism, Beta-Alanine metabolism, Fatty acid biosynthesis and Starch and sucrose metabolism. Next, we constructed a protein-protein interaction (PPI) network to identify hub genes in atherosclerosis. Also, we identified CDK6 as a key regulator of atherosclerosis. In this study, we found that CDK6 knockdown suppressed HASMC and HUASMC cell proliferation. Circular RNA (CircRNA) is a non-coding RNA which is reported to have an unusual influence on tumorigenesis process and other aspects in the last few years. Previous studies showed circRNAs could act as miRNAs sponging in multiple biological processes. Bioinformatics prediction and luciferase analysis showed that CDK6 were targeted and regulated by circHIPK3/miR-637. Moreover, silencing circHIPK3 could also significantly induce the arrest and apoptosis of cell cycle. In conclusion, this study discovered the important regulatory role of circHIPK3 in the proliferation and apoptosis of VSMCs by influencing the miR-637/CDK6 axis.