RGS2-mediated translational control mediates cancer cell dormancy and tumor relapse

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Slow-cycling cancer cells (SCCs) are crucial drivers of tumor relapse and drug resistance.
• Understanding the mechanisms of cancer cell dormancy is vital for improving patient outcomes, but is hindered by technical challenges.
• Targeting SCCs remains a significant challenge in non-small cell lung cancer (NSCLC) therapy.

Purpose of the Study:

• To identify and characterize a distinct subpopulation of SCCs in NSCLC.
• To elucidate the molecular mechanisms underlying SCC dormancy and survival.
• To explore novel therapeutic strategies targeting SCCs in NSCLC.

Main Methods:

• Utilized proliferation-sensitive dyes and chemotherapeutics in NSCLC cell lines and patient-derived xenografts.
• Performed transcriptional analysis to identify key regulatory molecules.
• Investigated the role of Regulator of G protein signaling 2 (RGS2) in SCC dormancy.
• Assessed the efficacy of RGS2 antagonism and phosphodiesterase 5 inhibitors in promoting SCC apoptosis.

Main Results:

• Identified a unique SCC subpopulation in NSCLC exhibiting dormancy phenotypes and high survival.
• Discovered that RGS2 upregulation drives SCC dormancy by promoting translational arrest via eIF2α phosphorylation and ATF4 degradation.
• RGS2 was validated as a biomarker for poor prognosis in NSCLC.
• RGS2 antagonism or sildenafil treatment induced apoptosis in SCCs under chemotherapy-induced stress.

Conclusions:

• RGS2 plays a critical role in maintaining non-small cell lung cancer cell dormancy and survival.
• Targeting RGS2 or activating translation in SCCs, potentially with agents like sildenafil, can overcome dormancy and induce apoptosis.
• Combination therapy involving low-dose chemotherapy and translation-activating agents shows promise for preventing tumor progression post-chemotherapy in NSCLC patients.