MicroRNA-145 transcriptionally regulates Semaphorin 3A expression in prostate cancer cells

Area of Science:

• Oncology
• Molecular Biology
• Gene Regulation

Background:

• Prostate cancer (PCa) is a leading male malignancy with microRNAs implicated in its pathogenesis.
• While microRNAs are typically cytoplasmic, nuclear localization and function, particularly for miR-145, remain underexplored in PCa.
• Reduced miR-145 and Semaphorin 3A (SEMA3A) expression are observed in PCa tissues.

Purpose of the Study:

• To investigate the nuclear function of miR-145 in prostate cancer.
• To determine the role of miR-145 in regulating Semaphorin 3A (SEMA3A) expression at the transcriptional level.
• To explore the tumor suppressor potential of miR-145 via SEMA3A induction.

Main Methods:

• Overexpression of miR-145 in PCa cell lines (PC3, DU145).
• Quantitative real-time PCR for miR-145 and SEMA3A mRNA.
• Cell viability assays, Western blot for protein analysis.
• Chromatin Immunoprecipitation (ChIP) and luciferase reporter assays to assess transcriptional regulation.

Main Results:

• miR-145 and SEMA3A expression were significantly downregulated in PCa cells (PC3, DU145) compared to normal prostate cells (PNT1a).
• Overexpression of miR-145 in PCa cells led to increased SEMA3A mRNA and protein levels.
• ChIP assay showed enrichment of RNA Polymerase II at the SEMA3A promoter upon miR-145 upregulation, and luciferase assays confirmed promoter activity.

Conclusions:

• miR-145 induces SEMA3A expression in prostate cancer cells at the transcriptional level.
• This study demonstrates a nuclear, transcriptional regulatory role for miR-145, extending beyond canonical gene silencing.
• miR-145's induction of SEMA3A suggests a potential mechanism for its tumor suppressor activity in PCa.