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Updated: Jul 6, 2025
Implementation of In Vitro Drug Resistance Assays: Maximizing the Potential for Uncovering Clinically Relevant Resistance Mechanisms
Published on: December 9, 2015
Characterization of dabrafenib-induced drug insensitivity via cellular barcoding and collateral sensitivity to
Rana Can Baygin1, Kubra Celikbas Yilmaz1, Ahmet Acar2
1Department of Biological Sciences, Middle East Technical University, Universiteler Mah. Dumlupınar Bulvarı 1, Çankaya, 06800, Ankara, Turkey.
Abstract:
Drug insensitivity is arguably one of the biggest challenges in cancer therapeutics. Although effective therapeutic solutions in cancer are limited due to the emergence of drug insensitivity, exploiting evolutionary understanding in this context can provide potential second-line therapeutics sensitizing the drug insensitive populations. Targeted therapeutic agent dabrafenib is used to treat CRC patients with BRAF V600E genotype and insensitivity to dabrafenib is often observed. Understanding underlying clonal architecture of dabrafenib-induced drug insensitivity and identification of potential second-line therapeutics that could sensitize dabrafenib insensitive populations remain to be elucidated. For this purpose, we utilized cellular barcoding technology to decipher dabrafenib-induced clonal evolution in BRAF V600E mutant HT-29 cells. This approach revealed the detection of both pre-existing and de novo barcodes with increased frequencies as a result of dabrafenib insensitivity. Furthermore, our longitudinal monitoring of drug insensitivity based on barcode detection from floating DNA within used medium enabled to identify temporal dynamics of pre-existing and de novo barcodes in relation to dabrafenib insensitivity in HT-29 cells. Moreover, whole-exome sequencing analysis exhibited possible somatic CNVs and SNVs contributing to dabrafenib insensitivity in HT-29 cells. Last, collateral drug sensitivity testing demonstrated oxaliplatin and capecitabine, alone or in combination, as successful second-like therapeutics in inducing collateral sensitivity in dabrafenib-insensitive HT-29 cells. Overall, our findings demonstrate clonal dynamics of dabrafenib-insensitivity in HT-29 cells. In addition, oxaliplatin and capecitabine, alone or in combination, were successful second-line therapeutics in inducing collateral sensitivity in dabrafenib-insensitive HT-29 cells.
Insights
Drug insensitivity is a major hurdle in cancer therapy. This study reveals how cellular barcoding tracks clonal evolution in dabrafenib-insensitive colorectal cancer cells, identifying oxaliplatin and capecitabine as potential second-line treatments.
Area of Science:
- Oncology
- Evolutionary Biology
- Genomics
Background:
- Drug insensitivity presents a significant challenge in cancer therapeutics, limiting treatment efficacy.
- BRAF V600E-mutated colorectal cancer (CRC) often develops insensitivity to targeted therapies like dabrafenib.
- Understanding the clonal dynamics driving drug insensitivity is crucial for developing effective second-line treatments.
Purpose of the Study:
- To investigate the clonal evolution underlying dabrafenib-induced drug insensitivity in BRAF V600E mutant HT-29 cells.
- To identify potential second-line therapeutics that can sensitize dabrafenib-insensitive cancer populations.
- To elucidate the temporal dynamics of clonal changes associated with dabrafenib insensitivity.
Main Methods:
- Utilized cellular barcoding technology to track clonal expansion and evolution in HT-29 cells under dabrafenib treatment.
- Employed longitudinal monitoring of cell-free DNA in spent medium to assess clonal dynamics.
- Performed whole-exome sequencing to identify somatic copy number variations (CNVs) and single nucleotide variations (SNVs).
- Conducted collateral drug sensitivity testing to evaluate potential second-line therapeutic agents.
Main Results:
- Cellular barcoding revealed increased frequencies of both pre-existing and de novo barcodes, indicating clonal selection and expansion in response to dabrafenib insensitivity.
- Longitudinal monitoring of cell-free DNA provided insights into the temporal dynamics of these clonal populations.
- Whole-exome sequencing identified potential genetic alterations (CNVs and SNVs) contributing to dabrafenib insensitivity.
- Oxaliplatin and capecitabine, individually or in combination, demonstrated efficacy in inducing collateral sensitivity in dabrafenib-insensitive HT-29 cells.
Conclusions:
- The study elucidates the clonal dynamics driving dabrafenib insensitivity in BRAF V600E mutant HT-29 colorectal cancer cells.
- Oxaliplatin and capecitabine show promise as effective second-line therapeutics for sensitizing dabrafenib-insensitive cancer.
- This research provides a foundation for developing evolutionary-informed therapeutic strategies against drug-resistant cancers.
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