Figure 4.

Resistance to Rego sensitizes Axl-expressing cells towards Afatinib. (A, B) Clonogenic growth behavior of control (naïve) and Rego-resistant SNU449 cells untreated (w/o) or treated with increasing concentrations of Afatinib in the Axl-proficient (A) and Axl-deficient background (B). Bar charts depict the quantification of colonies relative to control (right panels). (C, D) Dose-response curves of control and Rego-resistant SNU449 cells against Afatinib in the Axl-positive (C) and Axl-negative background (D). Bar charts show sensitivity (IC₅₀) against Afatinib relative to controls (C, D). (A–D) Sensitivities of controls were set to the value of 1. Data are expressed as mean +/- SD. ns: p > 0.05; *p ≤ 0.05; **p ≤ 0.01; Rego, Regorafenib.