Exosomal lncRNA HEIH promotes cisplatin resistance in tongue squamous cell carcinoma via targeting miR-3619-5p/HDGF axis.

Background Accumulating evidence has suggested that long noncoding RNAs (lncRNAs) are involved in the progression of types of human cancers. It has been known that exosomes can mediate cell-cell crosstalk by transferring lncRNAs in tumor progression. This study aimed to investigate the role of exosomal lncRNA HEIH on cisplatin (DDP) resistance in tongue squamous cell carcinoma (TSCC). Methods The expression of HEIH in human oral keratinocytes cell line (HOK), DDP-sensitive TSCC cell line (SCC4/S) and DDP-resistant TSCC cell line (SCC4/DDP) was measured. SCC4/S and SCC4/DDP cells were transfected with sh-HEIH to examine TSCC cell proliferation and apoptosis. The DDP-resistant exosomes were extracted and identified. The expression of miR‑3619-5p and TDGF in DDP-sensitive recipient cells was determined. The binding capacity between HEIH and miR‑3619-5p, along with miR‑3619-5p and TDGF was verified. Results HEIH expression was significantly upregulated in SCC4/DDP cells. Downregulation of HEIH inhibited DDP resistance and cell proliferation and promoted cell apoptosis. HEIH acted as a competing endogenous RNA (ceRNA) for miR‑3619-5p to upregulate HDGF expression. Exosomal HEIH promoted cell proliferation and drug resistance and inhibited cell apoptosis by sponging miR‑3169-5p and upregulating HDGF. Conclusion Exosomal HEIH acted as a ceRNA for miR‑3619-5p to upregulate HDGF, thereby promoting DDP resistance in TSCC cells.