Related Experiment Video
Updated: Aug 6, 2025
Circulating Tumor Cell Lines: an Innovative Tool for Fundamental and Translational Research
Published on: December 25, 2021
Profiling of Circulating Tumor Cells for Screening of Selective Inhibitors of Tumor-Initiating Stem-Like Cells
Chia-Lin Chen1, Juan Carlos Hernandez1,2, Dinesh Babu Uthaya Kumar1
1Departments of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, CA, 90033, USA.
Abstract:
A critical barrier to effective cancer therapy is the improvement of drug selectivity, toxicity, and reduced recurrence of tumors expanded from tumor-initiating stem-like cells (TICs). The aim is to identify circulating tumor cell (CTC)-biomarkers and to identify an effective combination of TIC-specific, repurposed federal drug administration (FDA)-approved drugs. Three different types of high-throughput screens targeting the TIC population are employed: these include a CD133 (+) cell viability screen, a NANOG expression screen, and a drug combination screen. When combined in a refined secondary screening approach that targets Nanog expression with the same FDA-approved drug library, histone deacetylase (HDAC) inhibitor(s) combined with all-trans retinoic acid (ATRA) demonstrate the highest efficacy for inhibition of TIC growth in vitro and in vivo. Addition of immune checkpoint inhibitor further decreases recurrence and extends PDX mouse survival. RNA-seq analysis of TICs reveals that combined drug treatment reduces many Toll-like receptors (TLR) and stemness genes through repression of the lncRNA MIR22HG. This downregulation induces PTEN and TET2, leading to loss of the self-renewal property of TICs. Thus, CTC biomarker analysis would predict the prognosis and therapy response to this drug combination. In general, biomarker-guided stratification of HCC patients and TIC-targeted therapy should eradicate TICs to extend HCC patient survival.
Insights
This study identifies a combination of histone deacetylase (HDAC) inhibitors and all-trans retinoic acid (ATRA) to effectively target cancer stem-like cells (TICs). Biomarker-guided therapy may improve treatment outcomes and reduce tumor recurrence.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Improving cancer therapy requires enhancing drug selectivity and reducing tumor recurrence from tumor-initiating cells (TICs).
- Circulating tumor cell (CTC) biomarkers and effective drug combinations are crucial for targeting TICs.
Purpose of the Study:
- To identify CTC-biomarkers for predicting prognosis and therapy response.
- To discover effective combinations of FDA-approved drugs targeting TICs.
Main Methods:
- High-throughput screening of CD133 (+) cell viability, NANOG expression, and drug combinations.
- Secondary screening targeting NANOG expression with FDA-approved drugs.
- RNA-sequencing (RNA-seq) analysis of TICs.
Main Results:
- A combination of histone deacetylase (HDAC) inhibitors and all-trans retinoic acid (ATRA) showed high efficacy in inhibiting TIC growth.
- Adding immune checkpoint inhibitors reduced recurrence and improved survival in mouse models.
- Combined drug treatment downregulated stemness genes and Toll-like receptors (TLRs) via repression of MIR22HG, inducing PTEN and TET2, and reducing TIC self-renewal.
Conclusions:
- CTC biomarker analysis can predict prognosis and response to the identified drug combination.
- Biomarker-guided stratification and TIC-targeted therapy, including HDAC inhibitors and ATRA, hold promise for eradicating TICs and extending survival in hepatocellular carcinoma (HCC) patients.
