CRISPR-mediated WNK4 point mutation aggravates tumor progression and weakens chemotherapy sensitivity in gastric cancer

Abstract

Objective. Gastric cancer (GC) is the fifth most common malignancy, the molecular targets of which have been increasingly explored in recent years. As a serine/threonine protein kinase, the role of WNK lysine deficient protein kinase 4 (WNK4) in GC was clarified in this study. Methods. Human GC lines AGS and MKN45 were stably transfected with a WNK4 mutant constructed by the CRISPR/Cas9 method and treated with cis-dichlorodiammine platinum (CDDP, 2 μg/mL) and 5-fluorouracil (5-FU, 5 μg/mL) for 48h. Tumor-bearing mice were established with 5×106 mutant-type AGS cells, and injected with 40 mg/kg WP1066, the inhibitor of signal transducer and activator of transcription 3 (STAT3), for 21 days. Cell malignant potential and tumor growth were assessed. STAT3 activation was identified by western blot and immunohistochemistry. The interaction between WNK4 and STAT3 was determined using co-immunoprecipitation and immunofluorescence co-localization. Results. WNK4 mutation promoted proliferation and invasion, and upregulated the p-STAT3/STAT3 value in GC cells with/without 5-FU and CDDP treatments, while inhibiting apoptosis of GC cells without drug treatment. In tumor-bearing mice, WNK4 mutation accelerated tumor growth, increased levels of p-STAT3, STAT3, and p-STAT3/STAT3, and strengthened the co-immunoprecipitation and co-localizing with STAT3; however, these effects were reversed by WP1066 treatment. Conclusion. Through activating STAT3, WNK4 mutation impacts both the natural and drug-treated growth of GC cells or tumors, suggesting a new avenue for preclinical research.