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BACKGROUND: The Copper Metabolism MURR1 (COMM) domain family has been reported to play important roles in tumorigenesis. As a prototype for the COMMD family, the expression pattern and biological function of COMMD6 in human tumours remain unknown. METHODS: COMMD6 expression in BALB/c mice and human tissues was examined using real-time PCR and immunohistochemistry. Kaplan-Meier analysis was applied to evaluate the prognosis of COMMD6 in tumours. Competing endogenous RNA (ceRNA) and transcriptional regulation network were constructed based on differentially expressed mRNAs, microRNAs and long non-coding RNAs from the cancer genome atlas database. GO and KEGG enrichment analysis were used to explore the bioinformatics implication. RESULTS: COMMD6 expression was widely observed in BALB/c mice and human tissues, which predicted prognosis of cancer patients. Furthermore, we shed light on the underlying tumour promoting role and mechanism of COMMD6 by constructing a TEX41-miR-340-COMMD6 ceRNA network in head and neck squamous cell carcinoma and miR-218-CDX1-COMMD6 transcriptional network in cholangiocarcinoma. In addition, COMMD6 may modulate the ubiquitination and degradation of NF-κB subunits and regulate ribonucleoprotein and spliceosome complex biogenesis in tumours. CONCLUSIONS: This study may help to elucidate the functions and mechanisms of COMMD6 in human tumours, providing a potential biomarker for tumour prevention and therapy.

Background Irradiation has emerged as a valid tool for nasopharyngeal carcinoma (NPC) in situ treatment; however, NPC derived from tissues treated with irradiation is a main cause cancer-related death. The purpose of this study is to uncover the underlying mechanism regarding tumor growth after irradiation and provided potential therapeutic strategy. Methods Fibroblasts were extracted from fresh NPC tissue and normal nasopharyngeal mucosa. Immunohistochemistry was conducted to measure the expression of α-SMA and FAP. Cytokines were detected by protein array chip and identified by real-time PCR. CCK-8 assay was used to detect cell proliferation. Radiation-resistant (IRR) 5-8F cell line was established and colony assay was performed to evaluate tumor cell growth after irradiation. Signaling pathways were acquired via gene set enrichment analysis (GSEA). Comet assay and γ-H2AX foci assay were used to measure DNA damage level. Protein expression was detected by western blot assay. In vivo experiment was performed subcutaneously. Results We found that radiation-resistant NPC tissues were constantly infiltrated with a greater number of cancer-associated fibroblasts (CAFs) compared to radiosensitive NPC tissues. Further research revealed that CAFs induced the formation of radioresistance and promoted NPC cell survival following irradiation via the IL-8/NF-κB pathway to reduce irradiation-induced DNA damage. Treatment with Tranilast, a CAF inhibitor, restricted the survival of CAF-induced NPC cells and attenuated the of radioresistance properties. Conclusions Together, these data demonstrate that CAFs can promote the survival of irradiated NPC cells via the NF-κB pathway and induce radioresistance that can be interrupted by Tranilast, suggesting the potential value of Tranilast in sensitizing NPC cells to irradiation.

Interferon-induced protein 44 (IFI44) containing a guanosine-5′-triphosphate (GTP) binding domain was reported to play a significant role in the immune response to autoimmune disease. However, its roles involved in cancers remain unclear. Here, we detected the expression of IFI44 in The Cancer Genome Atlas (TCGA) Pan-cancer and generally explored the effect of IFI44 on immune infiltration in the tumor microenvironment (TME). The results displayed that IFI44 was mainly located in the cytoplasm and overexpressed in head and neck squamous cell carcinoma (HNSC) samples compared with normal tissues. Survival analysis exhibited that IFI44 was remarkably associated with the clinical outcomes, particularly in lymph node-positive and locally advanced HNSC patients. Biological analysis showed that IFI44 was correlated with such immune biological processes as antigen-presenting and nuclear factor (NF)-kappa B signaling pathways. Immune signature analysis demonstrated that the expression of IFI44 was positively correlated with the infiltration of CD4 + cells and macrophages as well as neutrophils in HNSC. Taken together, these data suggested that IFI44 was abnormally expressed in cancer tissues and indicated the potential impact of IFI44 on the tumor immune infiltration in HNSC.