Ferroptosis promotes anti-tumor immune response by inducing immunogenic exposure in HNSCC.

Accumulated evidence indicates that immune cell populations play pivotal roles in the process of tumor initiation, progression, recurrence, metastasis, and immune escape. Ferroptosis is a form of regulating cell death in the nexus between metabolism, redox biology, and human health. Ferroptosis is considered as a vital important event in HNSCC, but the underling mechanism of regulating immune cell populations remains poorly understood. Our tissue microarray study showed that patients with high expression of GPX4 were related to poor survival. Moreover, the expression of GPX4 has been negatively associated with immunogenic cell death-related protein calreticulin in HNSCC tissue cohort. Further, RSL3 was used to induce ferroptosis in HNSCC xenograft of C3H/He mouse. We found that the occurrence of ferroptosis had significantly reduced the number of myeloid-derived suppressor cells (MDSCs) and tumor-associated M2-like macrophages (M2 TAMs) in tumor microenvironment. Meanwhile, the tumor-infiltrating CD4+ and CD8+ T cells were increased. And the calreticulin and HMGB1 may be potential candidate proteins improving the immunosuppressive tumor microenvironment. Taken together, our project suggests that ferroptosis can promote anti-tumor immune response by reversing immunosuppressive microenvironment, indicating that ferroptosis inducer is a promising therapeutic strategy in HNSCC.

MiR-125a-5p promotes osteoclastogenesis by targeting TNFRSF1B.

AIM: To investigate the dysregulation of microRNAs (miRNAs) during the differentiation of osteoclasts and the precise roles of miR-125a-5p in the differentiation of osteoclasts. METHODS: The cell model of RAW 264.7 osteoclast precursor cell differentiation induced by RANKL plus M-CSF stimulation was established. During the early stage of osteoclast differentiation, miRNA expression profiles were detected using the biochip technique and analyzed by cluster analysis. TargetScan, miRTarBase and miRDB database analysis was applied to find the key target genes of miR-125a-5p. A dual luciferase experiment was conducted to identify the direct target of miR-125a-5p. MiR-125a-5p mimic transfection and anti-miR-125-5p treatment were conducted to verify the role of miR-125q-5p in osteoclast differentiation. The levels of triiodothyronine receptor auxiliary protein (TRAP), matrix metallopeptidase 2 (MMP-2), MMP-9 and cathepsin K were analyzed by qRT-PCR and western blot assay. The expression levels of MMP-2 and MMP-9 were determined using western blotting and immunofluorescence assay. The migration and invasion of RAW 264.7 cells were assessed by wound healing and Transwell invasion assays. The proliferation of RAW 264.7 osteoclast precursor cells was detected using MTT assay. RESULTS: There were 44 microRNAs differently expressed during the differentiation of RAW 264.7 osteoclast precursor cells into osteoclasts, 35 of which were up-regulated and 9 were down-regulated. By luciferase reporter assay, it was confirmed that the TNF receptor superfamily member 1B gene (TNFRSF1B) was the target gene of miR-125a-5p. Up-regulation of miR-125a-5p inhibited TNFRSF1B protein expression and promoted osteoclast differentiation whereas down-regulation of miR-125a-5p caused completely opposite results. CONCLUSIONS: In conclusion, overexpression of miR-125a-5p suppresses the expression of TNFRSF1B and promotes osteoclast differentiation. These results reveal the crucial role of miR-125a-5p in the differentiation of osteoclasts.