Multiple familial trichoepithelioma (MFT) and familial cylindromatosis are two clinically distinct cancer syndromes. MFT patients developed mostly trichoepithelioma in the face while cylindromatosis patients developed cylindromas predominantly (approximately 90%) on the head and neck. However, multiple familial trichoepithelioma is occasionally associated with familial cylindromatosis while cylindromatosis patients can also develop trichoepithelioma. This has led to the speculation that the 2 types of dermatoses may be caused by dysfunction of a common pathway. Previously, a candidate MTF locus has been mapped to 9p21 while disease gene for familial cylindromatosis, the CYLD gene located on 16q21-13 has been identified. Here, we show that mutations in the CYLD gene are also the genetic basis for three different Chinese families with MFT. Sequence analysis reveal a single nucleotide deletion, c.1462delA (P.Ile488fsX9) in exon 9, a nonsense mutation, c.2128C>T (p. Gln710X) in exon 17, and a missense mutation, c.2822A>T (p. Asp941Val) in exon 21 in each of the three families respectively. This provides direct evidence that the mutations in CYLD can cause two clinically distinct cancer syndromes.

Background: A number of studies have demonstrated that N6‐methyladenosine (m6A) plays a vital role in the pathological process of various tumours. Recently, it was found that m6A writers or erasers affect the tumourigenesis of melanoma. However, the relationship between m6A readers such as YTH domain family (YTHDF) proteins and melanoma was still elusive.Methods: RT‐qPCR, Western blot and immunohistochemistry were conducted to measure the expression level of YTH N6–methyladenosine RNA binding protein 3 (YTHDF3) and lysyl oxidase–like 3 (LOXL3) in melanoma tissues and cells. The effects of YTHDF3 and LOXL3 on melanoma were verified in vitro and in vivo. Multi‐omics analysis including RNA‐seq, MeRIP‐seq, RIP‐seq and mass spectrometry analyses was performed to identify the target. The interaction between YTHDF3 and LOXL3 was verified by RT‐PCR, Western blot, MeRIP‐qPCR, RIP‐qPCR and CRISPR‐Cas13b‐based epitranscriptome engineering.Results: In this study, we found that m6A reader YTHDF3 could affect the metastasis of melanoma both in vitro and in vivo. The downstream targets of YTHDF3, such as LOXL3, phosphodiesterase 3A (PDE3A) and chromodomain helicase DNA‐binding protein 7 (CHD7) were identified by means of RNA‐seq, MeRIP‐seq, RIP‐seq and mass spectrometry analyses. Besides, RT‐qPCR, Western blot, RIP‐qPCR and MeRIP‐qPCR were performed for subsequent validation. Among various targets of YTHDF3, LOXL3 was found to be the optimal target of YTHDF3. With the application of CRISPR–Cas13b‐based epitranscriptome engineering, we further confirmed that the transcript of LOXL3 was captured and regulated by YTHDF3 via m6A binding sites. YTHDF3 augmented the protein expression of LOXL3 without affecting its mRNA level via the enrichment of eukaryotic translation initiation factor 3 subunit A (eIF3A) on the transcript of LOXL3. LOXL3 downregulation inhibited the metastatic ability of melanoma cells, and overexpression of LOXL3 ameliorated the inhibition of melanoma metastasis caused by YTHDF3 downregulation.Conclusions: The YTHDF3‐LOXL3 axis could serve as a promising target to be interfered with to inhibit the metastasis of melanoma.

The objective of this study is as follows. Inhibitor of growth (ING) 4 is a novel member of the ING family. It has been thought to play an inhibitory role in several malignancies through its involvment in gene transcription, apoptosis, cell cycle control, and tumor angiogenesis. The involvement of ING4 in melanomagenesis remains unknown. The purpose of this study was to investigate the inhibitory effects of ING4 on melanoma and its mechanisms. The method used was to construct recombinant plasmid pcDNA3.1-ING4 and transfect it into the human melanoma cell line M14. The effects and mechanisms of ING4 on proliferation and apoptosis of M14 cells were analyzed in vitro according to MTT assay, colony formation assay, and TUNEL assay. The detection of the expression of cell cycle or apoptosis regulators in transfected M14 cells was carried out by western blot analysis. Moreover, the level of ING4 in melanoma tissues was examined by immunohistochemistry. The expression of ING4 was markedly reduced in cutaneous melanoma tissues. Overexpression of ING4 could induce growth suppression and apoptosis enhancement in M14 cells, and also induce the upregulation of p27, Bax and Cyt-c, and the downregulation of cyclinD1, SKP2, Bcl-2, and caspase-3. In conclusion, ING4, as a novel tumor suppressor, has a potential role in growth suppression and apoptosis enhancement of melanoma M14 through the activation of the mitochondrial-induced apoptotic pathway and the hindrance of cell cycle progression. The deregulation of ING4 might be involved in melanomagenesis.

Triptolide Inhibits Proliferation and Induces Apoptosis of Human Melanoma A375 Cells Triptolide;melanoma A375 cells;apoptosis;caspase;NF-${\kappa}B$; Triptolide, a diterpenoid obtained from Tripteryglum wilfordii Hook.f, has attracted interest for its antitumor activities against human tumor cell lines in recent years. This report focuses on anti-proliferative and pro-apoptotic activities in human melanoma A375 cells assessed by CCK8 assay, Hoechst 33258 staining and flow cytometry. In addition, triptolide-induced arrest in the S phase was also observed. Caspase assays showed the apoptosis induced by triptolide was caspase-dependent and probably through intrinsic apoptotic pathways. Furthermore, expression of NF-${\kappa}B$ (p65) and its downstream factors such as Bcl-2, Bcl-$X_L$ was down-regulated. Taken together, the data indicate that triptolide inhibits A375 cells proliferation and induces apoptosis by a caspase-dependent pathway and through a NF-${\kappa}B$-mediated mechanism.