Intrabody Targeting HIF-1α Mediates Transcriptional Downregulation of Target Genes Related to Solid Tumors

Area of Science:

• Oncology
• Molecular Biology
• Biotechnology

Background:

• Solid tumors often develop hypoxic conditions, stabilizing hypoxia-inducible factor-1α (HIF-1α).
• HIF-1α regulates genes involved in tumor metabolism, proliferation, and metastasis, making it a therapeutic target.
• Inhibiting HIF-1α transcriptional activity presents a potential cancer therapy strategy.

Purpose of the Study:

• To select and characterize nanobodies (Nbs) that inhibit the transcriptional activity of HIF-1α.
• To evaluate the efficacy of these Nbs in suppressing HIF-1α-regulated gene expression in cancer cells.

Main Methods:

• Construction of immune and synthetic libraries for phage display selection of Nbs against the PAS B domain of HIF-1α.
• Selection and screening of nanobodies, followed by immunoprecipitation to confirm binding to native HIF-1α.
• Intracellular expression of selected Nbs in HeLa cells to assess their inhibitory effect on HIF-1-induced gene activation.

Main Results:

• Seven distinct nanobodies were selected, with five confirmed to target the native HIF-1α subunit.
• Intracellular expression of intrabody formats demonstrated significant inhibition of HIF-1-related target gene expression.
• The results confirm the inhibitory efficacy of the selected nanobodies on HIF-1α transcriptional activity.

Conclusions:

• Novel nanobodies targeting HIF-1α have been successfully developed.
• These nanobodies effectively inhibit HIF-1α transcriptional activity and the expression of its target genes.
• The selected nanobodies show promise as a potential therapeutic strategy for hypoxic solid tumors.