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DNA Methylation Analysis in Plasma Cell-Free DNA and Paired CTCs of NSCLC Patients before and after Osimertinib
Aliki Ntzifa1, Dora Londra1, Theodoros Rampias2
1Analysis of Circulating Tumor Cells Lab, Lab of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece.
Abstract:
Osimertinib has been an effective second-line treatment in EGFR mutant NSCLC patients; however, resistance inevitably occurs. DNA methylation has been previously implicated in NSCLC progression and often in therapy resistance, however its distinct role in osimertinib resistance is not elucidated as yet. In the present study, we directly compared DNA methylation of nine selected genes (RASSF1A, RASSF10, APC, WIF-1, BRMS1, SLFN11, RARβ, SHISA3, and FOXA1) in plasma-cfDNA and paired CTCs of NSCLC patients who were longitudinally monitored during osimertinib treatment. Peripheral blood (PB) from 42 NSCLC patients was obtained at two time points: (a) baseline: before treatment with osimertinib and (b) at progression of disease (PD). DNA methylation of the selected genes was detected in plasma-cfDNA (n = 80) and in paired CTCs (n = 74). Direct comparison of DNA methylation of six genes between plasma-cfDNA and paired CTC samples (n = 70) revealed a low concordance, indicating that CTCs and cfDNA give complementary information. DNA methylation analysis of plasma-cfDNA and CTCs indicated that when at least one of these genes was methylated there was a statistically significant increase at PD compared to baseline (p = 0.031). For the first time, DNA methylation analysis in plasma-cfDNA and paired CTCs of NSCLC patients during osimertinib therapy indicated that DNA methylation of these genes could be a possible resistance mechanism.
Insights
DNA methylation in circulating tumor DNA and cells may indicate resistance to osimertinib in non-small cell lung cancer (NSCLC). This study compared methylation in plasma-cfDNA and CTCs, finding complementary information and a significant increase at disease progression.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Osimertinib is a key treatment for EGFR-mutant non-small cell lung cancer (NSCLC), but resistance is a significant clinical challenge.
- DNA methylation is implicated in cancer progression and therapy resistance, yet its specific role in osimertinib resistance remains unclear.
- Understanding resistance mechanisms is crucial for improving NSCLC treatment strategies.
Purpose of the Study:
- To investigate the role of DNA methylation in plasma-circulating cell-free DNA (cfDNA) and paired circulating tumor cells (CTCs) as a mechanism of osimertinib resistance in NSCLC.
- To compare DNA methylation patterns between plasma-cfDNA and CTCs in NSCLC patients undergoing osimertinib treatment.
- To identify potential epigenetic biomarkers for predicting or monitoring osimertinib resistance.
Main Methods:
- Longitudinal analysis of DNA methylation in nine selected genes (RASSF1A, RASSF10, APC, WIF-1, BRMS1, SLFN11, RARβ, SHISA3, FOXA1).
- Samples collected from 42 NSCLC patients at baseline (pre-osimertinib) and at disease progression (PD).
- DNA methylation analysis performed on plasma-cfDNA and paired CTCs.
Main Results:
- Low concordance was observed between DNA methylation in plasma-cfDNA and paired CTCs, suggesting complementary diagnostic information.
- A statistically significant increase in DNA methylation of the selected genes was detected in both plasma-cfDNA and CTCs at disease progression compared to baseline (p = 0.031).
- The findings indicate that increased DNA methylation in these genes may be associated with the development of osimertinib resistance.
Conclusions:
- DNA methylation analysis in plasma-cfDNA and CTCs offers complementary insights into osimertinib resistance mechanisms in NSCLC.
- Epigenetic alterations, specifically DNA methylation, represent a potential mechanism driving resistance to osimertinib therapy.
- This study provides novel evidence for DNA methylation as a biomarker for resistance in EGFR-mutant NSCLC treated with osimertinib.
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