TIPRL Regulates Stemness and Survival in Lung Cancer Stem Cells through CaMKK2-CaMK4-CREB Feedback Loop Activation

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Cancer stem cells (CSCs) drive lung cancer recurrence and metastasis, posing significant treatment challenges.
• Identifying specific CSC targets is crucial for developing effective targeted therapies.

Purpose of the Study:

• To investigate the role of TOR Signaling Pathway Regulator-Like (TIPRL) in lung CSCs.
• To elucidate the molecular mechanisms by which TIPRL contributes to lung cancer progression.
• To evaluate TIPRL and the CaMKK2 signaling axis as potential therapeutic targets.

Main Methods:

• Investigated TIPRL expression and its interaction with CaMKK2 in lung CSCs.
• Analyzed the CaMKK2-CaMK4-CREB signaling pathway activation.
• Assessed the effect of TIPRL depletion on CSCs' sensitivity to afatinib and metastasis in vivo.
• Determined the regulatory relationship between CREB and TIPRL.

Main Results:

• Upregulated TIPRL sustains CaMKK2 pathway activation, maintaining lung CSC stemness and survival.
• CaMKK2-CaMK4-CREB axis activation leads to phosphorylation of CREB and downstream gene expression (Bcl2, HMG20A).
• TIPRL depletion sensitizes lung CSCs to afatinib and reduces metastasis; CREB positively regulates TIPRL transcription, forming a feedback loop.

Conclusions:

• The TIPRL-CaMKK2 signaling axis, driven by a CREB-TIPRL positive feedback loop, promotes lung cancer tumorigenesis, stemness, and survival.
• Targeting TIPRL and the CaMKK2 pathway offers a promising strategy to overcome drug resistance and reduce metastasis in lung cancer.