Figure 4

miR-146a-5p regulation and effect on drug response may be mutation-specific. (a) RNAseq shows that in both cases, EGFR transcripts are expressed at similar levels in both culture conditions and the tissue of origin. (b) Case A shows miR-146a-5p downregulation in 2D, reflecting the data collected from HCC827, while Case B shows no significant change. RT-qPCR; fold change relative to flash frozen control. Each point represents the mean of three technical replicates. Kruskal–Wallis test with Dunn’s correction for multiple comparisons. **p = 0.0045. (c) When challenged with 75 nM erlotinib for 72 h, Case A shows significantly higher resistance in 3D culture, which aligns with that seen in the HCC827 cells. Case B shows a nonsignificant difference in response. Each point represents a single well (2D) or spheroid (3D), and all spheroids of consistent size and shape were used. Kolmogorov–Smirnov test, p = 0.0476. (d) RNAseq shows that Case A carries the same EGFR exon 19 deletion as HCC827, while Case B carries an exon 20 insertion.