Harnessing CRISPR/Cas9 to overcome targeted therapy resistance in non‑small cell lung cancer: Advances and challenges (Review)

Abstract

Targeted therapy has markedly improved outcomes for patients with non‑small cell lung cancer (NSCLC). However, the emergence of drug resistance remains a major clinical challenge, limiting long‑term treatment efficacy. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9, a revolutionary gene‑editing technology, offers precise and efficient genetic modifications, providing new insights into the mechanisms of drug resistance in NSCLC. The present review explored the application of CRISPR/Cas9 in overcoming resistance associated with key oncogenic drivers, including EGFR, KRAS, ALK, ROS1, MET and BRAF. It summarized recent advances in CRISPR‑based strategies to reverse resistance, enhance targeted therapy effectiveness and develop potential therapeutic interventions. Additionally, it discussed current limitations, including off‑target effects, delivery challenges and ethical concerns, while highlighting future directions for clinical translation. Using CRISPR/Cas9 technology may pave the way for novel, personalized treatment approaches in NSCLC, ultimately improving patient outcome.

Keywords: clustered regularly interspaced short palindromic repeats/Cas9; drug resistance; non‑small cell lung cancer; oncogene; targeted therapy.

Figure 1.

Genes and pathways in non-small cell lung cancer targeted drug resistance.

Figure 2.

CRISPR-Cas9 system. (A) CRISPR-Cas9 nuclease binds to a gRNA to form a ribonucleoprotein complex. The gRNA directs Cas9 to a complementary DNA target site, inducing DSBs. Cellular repair pathways resolve DSBs via NHEJ, which introduces insertions or deletions (indels), or HDR for template-dependent precision editing. (B) Catalytically dCas9 is fused to transcriptional activators (such as VP64 or p65). The dCas9-activator complex binds to promoter regions via gRNA targeting, recruiting transcriptional machinery to upregulate gene expression. (C) dCas9 is fused to transcriptional repressors. The dCas9-repressor complex blocks transcription initiation or elongation by sterically hindering RNA polymerase or cofactor recruitment at promoter targets. (D) dCas9 is fused to a deaminase enzyme. The deaminase chemically modifies specific DNA bases without inducing DSBs, enabling precise single-nucleotide editing. (E) A Cas9 nickase fused to reverse transcriptase binds a pegRNA. The pegRNA directs nicking of the DNA strand encodes a RT template. RT synthesizes the edited sequence from the template, enabling targeted insertions, deletions, or substitutions with minimal unintended edits. CRISPR, clustered regularly interspaced short palindromic repeats; gRNA, guide RNA; DSBs, double-strand breaks; NHEJ, non-homologous end joining; HDR, homology-directed repair; CRISPRa, CRISPR activation; dCas9, inactive Cas9; CRISPRi, CRISPR interference; pegRNA, prime editing guide RNA; RT, reverse transcriptase.

Figure 3.

The applications of the CRISPR/Cas9 system. CRISPR, clustered regularly interspaced short palindromic repeats.