A keloid is a disease of excessive fibrosis that is characterized by the aberrant proliferation of fibroblasts. However, the molecular mechanisms of fibroblasts during the development of keloids remain unclear. This study aims to identify new molecular targets that promote the proliferation and migration of keloid fibroblasts, providing new ideas for the prevention and treatment of keloids. We utilized bioinformatics tools to analyze data from keloid fibroblasts (KFs) available in the Gene Expression Omnibus (GEO) database to identify the key genes involved in keloid development. Homeobox C6 (HOXC6) emerged as a hub gene in KFs from the GEO database was verified in keloid tissue samples and KFs using reverse transcription-quantitative polymerase chain reaction, western blot (WB) and immunohistochemistry. Subsequently, the effects of downregulated HOXC6 expression on the cellular behaviors of KFs were examined by performing Cell Counting Kit-8, flow cytometry, transwell migration and WB assays. Meanwhile, we performed transcriptome sequencing and gene set enrichment analysis (GSEA) to further explore HOXC6-related mechanisms and validated the signaling pathways by performing a series of experiments. HOXC6 was the top-ranking hub gene of KFs in microarray datasets from GEO and was upregulated in keloid tissue samples and KFs. Downregulation of HOXC6 inhibited proliferation, migration and extracellular matrix (ECM) accumulation and promoted KF apoptosis. GSEA predicted that the hypoxia signaling pathway was associated with HOXC6 in KFs. Transcriptome sequencing suggested that the extracellular regulated protein kinase (ERK) pathway was one of the downstream pathways of HOXC6 in KFs. Our experiments confirmed that hypoxia-inducible factor-1α (HIF-1α) upregulates HOXC6, contributing to KFs proliferation, migration, apoptosis inhibition and collagen accumulation through the ERK signaling pathway. Our findings first revealed that HOXC6 acts as an oncogenic driver in the molecular mechanisms of fibroblasts in keloids. The HIF-1α/HOXC6/ERK axis promotes proliferation, migration and ECM production by KFs, contributing to the progression of keloids. Taken together, HOXC6 may serve as a promising novel therapeutic target and new focus for research designed to understand the pathogenesis of keloids.

Cancer stem cells (CSCs) are closely related to tumor occurrence, development, metastasis, drug resistance, and recurrence. The role of CSCs in melanoma is poorly understood. Our previous studies suggested that the NOP14 nucleolar protein (NOP14) is involved in melanoma pathogenesis regulation. Importantly, NOP14 overexpression inhibits the Wnt/beta (β)-catenin signaling pathway, an important mechanism regulating CSCs stemness. Therefore, in this study, we aimed to explore the role of NOP14 in the stemness and function of CSCs in melanoma in vitro. CD133, a stem cell marker, was used to identify melanoma stem-like cells (SLCs). NOP14 overexpression subsequently decreased the proportion of CD133⁺ SLCs, impaired the colony-forming capabilities, and downregulated the expression of Nanog, SOX2, and OCT4 stem cell markers in A375 and A875 cells, suggesting that NOP14 suppresses the stemness of melanoma SLCs. NOP14 overexpression suppressed the migration, invasion, and angiogenesis-inducing ability of A375-SLCs and A875-SLCs. NOP14 overexpression also inactivated Wnt/β-catenin signaling in melanoma CD133⁺ SLCs. The Wnt signaling activator BML-284 alleviated the effect of NOP14 overexpression on the stemness and function of melanoma CSCs. In conclusion, NOP14 suppresses the stemness and function of melanoma SLCs by inactivating Wnt/β-catenin signaling. Thus, NOP14 is a novel target for CSC treatment in melanoma. Abbreviations: CSCs, cancer stem cells; SLCs, stem-like cells; NOP14, NOP14 nucleolar protein; SCID, severe combined immunodeficiency; β-catenin, beta-catenin; lv-NOP14, lentivirals expressing NOP14; PBS, phosphate buffer saline; HUVECs, human umbilical vein endothelial cells.