Bulk RNA-Seq Combined with Single-Cell Transcriptome Sequencing Reveals the Possible Mechanisms by Which HDGFL3 Involves in Prostate Cancer Growth and Metastasis

Background: Based on publicly available transcriptome and single-cell sequencing data, the current study aimed to explore the molecular mechanisms underlying the involvement of hepatocellular carcinoma-derived growth factor-like 3 (HDGFL3) in prostate cancer (PCA) growth and metastasis. Methods: The Gene Expression Omnibus database was used to download the single cell transcriptome of PCA (GSE193337). Single-cell RNA sequencing (scRNA-seq) data were examined to identify which genes are essential for endothelial cell function. The Cancer Genome Atlas Prostate Adenocarcinoma database provided the RNA sequencing data, and univariate COX regression analysis was introduced to identify the genes that were associated with the prognosis of patients with PCA. Human PCA cell lines PC-3 and DU145 were used in in vitro cellular studies to test the effect of silencing HDGFL3. The results were validated using Transwell® assay, scratch assay, and cell counting kit-8 assay. To support the role of HDGFL3 in PCA, an in vivo animal model of PCA transplantation tumor in nude mice was established. Quantitative reverse transcription polymerase chain reaction was introduced to measure HDGFL3 messenger ribonucleic acid (mRNA) expression levels in tumor tissues from nude mice, and Hematoxylin and Eosin staining was used to identify lung metastasis. Immunohistochemical staining was employed to identify the expression levels of HDGFL3 and hematopoietic progenitor cell antigen CD34⁺. Results: It was discovered through analysis of the scRNA-seq dataset that HDGFL3, a gene specific to endothelial cells, is linked to a poor prognosis in men with PCA. In addition, HDGFL3 and the expression of genes linked to angiogenesis have a substantial association. Studies on cells in vitro revealed that silencing HDGFL3 prevented PC-3 and DU145 cells from proliferation, migrating and invading. Silencing HDGFL3 decreased the weight of prostate tumors, the number of lung metastases, and the area occupied by CD34⁺ vascular endothelial cells, according to in vivo investigations. Conclusions: This study identified HDGFL3 as a key gene in endothelial cells that may stimulate tumor angiogenesis to increase the growth and spread of PCA. These results imply that HDGFL3 may represent a possible target for antiangiogenic therapy in the management of PCA.