The Mechanism by Which Hedgehog Interacting Protein (HHIP) in Cancer-Associated Fibroblasts Regulate the Secretion of Inflammatory Factors Through the JAK1/STAT3 Pathway Affecting Prostate Cancer Stemness.

Purpose: Prostate cancer (PCa) is seriously affecting men's health and quality of life. Existing studies indicate that PCa stem cells are responsible for promoting the growth and contributing to the high recurrence rate of PCa.

Methods: We retrieved and downloaded PCa-related datasets from both the GEO and TCGA database. These datasets were subsequently analyzed using single-cell analysis, difference analysis, WGCNA, and machine learning algorithms. WB was performed to detect the expression of Hedgehog interacting protein (HHIP), JAK1/STAT3 pathway-related protein, CD133 and CD44. Immunohistochemistry was conducted to assess the distribution of HHIP and Ki67. The levels of inflammatory factors were measured using ELISA. The tumor cell stemness was evaluated through spheroid formation assay and flow cytometry.

Results: Through bioinformatics analysis, we identified eight genes (ARHGAP24, HHIP, MITF, CBX7, PPP1R12B, PLEKHA1, ADGRA2, and PGR). Among these genes, we selected HHIP for follow-up experiments and confirmed its low expression in PCa tumor tissues. Primary cancer-associated fibroblasts (CAFs) were extracted, and to further explore the mechanism of HHIP, we overexpressed or knocked down HHIP in CAFs. Overexpression of HHIP was found to inhibit the JAK1/STAT3 pathway and the secretion of inflammatory factors, thus suppressing both the proliferation and stemness of PCa cells. Treatment of CAFs with the JAK1/STAT3 pathway inhibitor AG490 led to a decrease in inflammatory factor secretion, along with inhibition of PCa cell proliferation and stemness. On this basis, knockdown of HHIP partially reversed the inhibitory effects of AG490 on PCa cells. Finally, we constructed a mouse subcutaneous tumor model and found that HHIP inhibited tumor proliferation and densification.

Conclusion: In summary, HHIP in CAFs can regulate the JAK1/STAT3 pathway and affect the secretion of inflammatory factors, thus affecting the proliferation of PCa.