Exploring miR-21 Knock-Out Using CRISPR/Cas as a Treatment for Lung Cancer

Lung cancer is a leading cause of cancer-related deaths worldwide. Its high incidence and poor prognosis demonstrate the need to investigate new therapies. The PI3K/AKT pathway is activated in carcinogenic processes such as invasion, proliferation, and drug resistance. MiR-21 is a microRNA overexpressed in numerous types of cancer and which activates PI3K/AKT pathway by down-regulating its main targets, PTEN and PDCD4. CRISPR is a revolutionary gene-editing technology that allows genes to be deleted. The aim of this study was to use CRISPR/Cas9 technology as an option to reduce carcinogenic and drug resistance processes by eliminating miR-21.

CRISPR/Cas9 was used to knock out miR-21 (miR-21 KO) in A549 lung cancer cells and thus reverse the carcinogenic processes activated by miR-21 overexpression. Furthermore, the effect of miR-21 KO on drug resistance was studied, choosing the main chemotherapeutic agents used for the treatment of lung cancer: gemcitabine, carboplatin, paclitaxel, and oxaliplatin.

miR-21 KO A549 cells exhibited a reduction in proliferation, migration, and colony formation compared to A549 cells. In contrast, the expression of PTEN and PDCD4 increased in miR-21 KO A549 cells. Furthermore, miR-21 KO A549 cells showed a decrease in the IC₅₀ of the drugs used for the treatment of lung cancer: gemcitabine, carboplatin, paclitaxel, and oxaliplatin.

Based on these results, miR-21 knock-out using CRISPR/Cas could be a promising strategy for the treatment of lung cancer.