Targeting METTL3 enhances the chemosensitivity of non-small cell lung cancer cells by decreasing ABCC2 expression in an m6A-YTHDF1-dependent manner

Patients with non-small cell lung cancer (NSCLC) are easily resistant to first-line chemotherapy with paclitaxel (PTX) or carboplatin (CBP). N⁶-methyladenosine (m⁶A) methyltransferase-like 3 (METTL3) has crucial functions in m⁶A modification and tumorigenesis. However, its role in chemoresistance of NSCLC is still elusive. Here, we demonstrated that METTL3 inhibitor STM2457 significantly reduced the IC₅₀ values of PTX or CBP in NSCLC cells, and they showed a synergistic effect. Comparing with monotherapy, a combination of STM2457 and PTX or CBP exhibited more potent in vitro and in vivo anti-tumor efficacy. In addition, we found that ATP binding cassette subfamily C member 2 (ABCC2) was responsively elevated in cytomembrane after PTX or CBP treatment, and targeting METTL3 could reverse this effect. Mechanistically, targeting METTL3 decreased the m⁶A modification of ABCC2 mRNA and accelerated its mRNA degradation. Further studies revealed that YTHDF1 could bind and stabilize the m⁶A-modified mRNA of ABCC2, while YTHDF1 knockdown promoted it mRNA degradation. These results, taken together, demonstrate that targeting METTL3 enhances the sensitivity of NSCLC cells to PTX or CBP by decreasing the cytomembrane-localized ABCC2 in an m⁶A-YTHDF1-dependent manner, and suggest that METTL3 may be a potential therapeutic target for acquired resistance to PTX or CBP in NSCLC.