DCAF12 Ubiquitin Ligase Promotes Lung Cancer Metastasis by Modulating the TRiC/CCT Chaperonin Complex

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• Metastasis remains a critical challenge in lung cancer treatment.
• The role of ubiquitin ligases in reprogramming chaperone networks to promote metastasis is not well understood.

Purpose of the Study:

• To elucidate the mechanism by which DDB1-CUL4-associated factor (DCAF12) regulates metastatic progression.
• To investigate the therapeutic potential of targeting the DCAF12-TRiC/CCT axis in lung cancer.

Main Methods:

• Depletion of DCAF12 in lung cancer cells.
• In vitro assays for cell migration and stemness.
• In vivo metastasis models (pulmonary/hepatic).
• Analysis of TRiC/CCT subunit ubiquitination and client protein folding.
• Assessment of YAP, STAT3, and mTOR pathway activation.
• Genetic knockdown and pharmacological inhibition (HSF1A) of the DCAF12-TRiC/CCT axis.
• Clinical correlation analysis of DCAF12 expression with patient survival and metastasis.

Main Results:

• DCAF12 depletion suppressed lung cancer cell migration, stemness, and reduced metastasis in vivo.
• DCAF12 was found to catalyze non-degradative ubiquitination of TRiC/CCT subunits, enhancing chaperonin assembly.
• This process promoted folding of cytoskeletal proteins (β-actin/tubulin) and oncogenic clients (STAT3/Raptor/mLST8), activating YAP, STAT3, and mTOR pathways.
• Genetic and pharmacological targeting of the DCAF12-TRiC/CCT axis potently inhibited metastasis.
• Clinical data showed DCAF12 overexpression correlated with YAP/STAT3 activation, advanced metastasis, and poor patient survival.

Conclusions:

• Ubiquitination-mediated TRiC/CCT regulation acts as a metastatic switch in lung cancer.
• DCAF12 functions as an oncogenic proteostasis hub, driving metastatic progression.
• The DCAF12-TRiC/CCT axis represents a novel therapeutic target for metastatic lung cancer, with potential for multimodal targeting.