1G6-D7 Inhibits Homologous Recombination Repair by Targeting Extracellular HSP90α to Promote Apoptosis in Non-Small...

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Non-small cell lung cancer (NSCLC) presents a significant mortality challenge, necessitating further research into its pathogenesis and novel therapeutic strategies.
• Homologous recombination repair (HRR) is crucial for repairing DNA double-strand breaks; its deficiency (HRD) leads to genomic instability and cancer development.
• Poly(ADP-ribose) polymerase (PARP) inhibitors are effective against HRD-positive tumors, while extracellular heat shock protein 90α (eHSP90α) promotes cancer cell survival.

Purpose of the Study:

• To investigate the intricate relationship between extracellular heat shock protein 90α (eHSP90α) and homologous recombination repair (HRR) in non-small cell lung cancer (NSCLC).
• To evaluate the potential of targeting eHSP90α in combination with PARP inhibitors for NSCLC treatment.

Main Methods:

• Established DNA damage models in NSCLC cell lines (A549, H1299) to assess DNA damage, HRR marker activation, apoptosis, proliferation, and migration.
• Utilized in vivo tumor models in BALB/c nude mice with A549 cells.
• Employed human recombinant HSP90α stimulation, eHSP90α monoclonal antibody (1G6-D7), and LRP1 knockdown.

Main Results:

• Recombinant HSP90α enhanced HRR and reduced DNA damage, while the 1G6-D7 antibody inhibited HRR.
• LRP1 knockdown led to HRR inhibition and increased apoptosis, an effect not reversed by hrHSP90α.
• The combination of 1G6-D7 and olaparib (a PARP inhibitor) induced significant apoptosis and HRR inhibition in vitro, with promising anti-tumor effects in vivo.

Conclusions:

• Extracellular HSP90α appears to influence HRR in NSCLC, potentially via LRP1.
• The combination of the 1G6-D7 antibody and PARP inhibitors demonstrates a potent anti-tumor strategy for NSCLC.
• This combined approach may exert therapeutic effects by impeding DNA repair mechanisms and promoting cancer cell apoptosis.