Questiomycin A stimulates sorafenib-induced cell death via suppression of glucose-regulated protein 78

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Hepatocellular carcinoma (HCC) presents significant treatment challenges due to limited effective chemotherapies.
• Sorafenib, the current first-line treatment for HCC, offers modest survival benefits with low response rates.
• Identifying agents that potentiate sorafenib's efficacy is crucial for improving HCC therapeutic options.

Purpose of the Study:

• To investigate novel therapeutic strategies for hepatocellular carcinoma (HCC).
• To identify agents that can enhance the efficacy of sorafenib, the standard HCC treatment.
• To explore the role of endoplasmic reticulum (ER) stress and GRP78 in sorafenib-induced cell death.

Main Methods:

• Investigated the effect of questiomycin A on GRP78 expression in HCC cells.
• Analyzed the molecular mechanisms underlying questiomycin A's action on GRP78.
• Evaluated the synergistic effect of combining sorafenib and questiomycin A in HCC cell death.
• Assessed the in vivo efficacy of the combination therapy in HCC xenograft models.

Main Results:

• The compound questiomycin A was found to suppress GRP78, a protective ER chaperone protein.
• Quiestiomycin A induced GRP78 protein degradation independently of ER stress.
• Combined treatment with sorafenib and questiomycin A reduced GRP78 expression, enhancing sorafenib-induced cell death.
• In vivo studies demonstrated that coadministration of sorafenib and questiomycin A suppressed tumor growth in HCC xenograft models.

Conclusions:

• Cotreatment with sorafenib and questiomycin A represents a novel therapeutic strategy for HCC.
• This combination enhances sorafenib-dependent ER stress-induced cell death.
• Downregulation of GRP78 is identified as a potential target to boost sorafenib's therapeutic effects in HCC.
• This approach offers a promising avenue for developing more effective treatments for hepatocellular carcinoma.