RN7SL1 overexpression promotes cell proliferation in cutaneous T-cell lymphoma via miR-34a-5p/MYCN axis.

Background: Cutaneous T-cell lymphoma (CTCL) is a type of lymphoma that presents in skin tissue without evidence of extracutaneous disease. Emerging evidence indicates that long noncoding RNA-RN7SL1 serves as crucial effectors in modulating progression of different malignancies, including breast cancer, liver cancer, and other neoplasms.

Objective: To figure out the role of RN7SL1 in the pathogenesis of CTCL.

Methods: We detected RN7SL1 expression of CTCL patients by quantitative real-time polymerase chain reaction and fluorescent in situ hybridization. CTCL cell lines were transfected with lentiviral-based RN7SL1 gene knockdown vectors. Whole transcriptome sequencing was conducted to investigate differentially expressed miRNA and mRNA in CTCL, and we used qRT-PCR, RNA immunoprecipitation, dual-luciferase assay, RNA pull down and Western Blotting to further detect the relation of miRNA and mRNA. Also, we have verified above results in mice and clinical samples.

Results: LncRNA-RN7SL1 was overexpressed in CTCL compared with benign inflammatory dermatosis and was related to the TNMB stage of mycosis fungoides and Sézary syndrome (higher expression in IIB-IVB stage than IA-IIA stage). Additionally, the proliferation of CTCL cell lines HH and Hut78 was weakened, but apoptosis was facilitated by RN7SL1 downregulation, resulting in a reduced tumorigenic capacity in vivo. Subsequently, Whole transcriptome sequencing and target validation indicated that the RN7SL1/miR-34a-5p/MYCN axis may promoted malignant behavior in CTCL.

Conclusion: Our study suggested that RN7SL1 promoted malignant behavior by targeting miR-34a-5p/MYCN signaling. This finding might facilitate the discovery of novel biomarkers for CTCL diagnosis and treatment.