Fig 2: Representative images of beta-arrestin-1 (ARRB1) and beta-arrestin-2 (ARRB2) IHC staining in lung ADC and SCC samples. Automated IHC was performed on sections from the in-house TMA using antibodies that recognise specifically beta-arrestin-1 or beta-arrestin-2. DAB-based visualisation was used to assess protein expression. IHC images in a three ADC samples and b three SCC samples are shown. Results from the same patient samples as those represented in Fig. 2 are displayed here

Fig 3: Plasma levels of beta-arrestin-1 (ARRB1) in lung cancer patients and healthy donors. a Scatter plots of plasma beta-arrestin-1 concentration obtained from lung cancer patients (n = 128) and healthy volunteers (n = 93) using the PRM assay targeting EDLDVLGLTFR. Data points and their median are shown. PRM data from the lung cancer patients were further divided into ADC (n = 72) and SCC (n = 24) groups in the same graph. PRM readout of beta-arrestin-1 measured in one of the lung cancer patient samples is shown in b with the traces of detected product ions of the peptide EDLDVLGLTFR compared to the ones of internal standard peptide shown in c. PRM readout of beta-arrestin-1 measured in one of the healthy volunteer samples is shown in d indicating no signal was detected compared to the internal standard shown in e. ****P < 0.0001 using Mann–Whitney rank sum test

Fig 4: Role of ß-arrestin2 in IGF-1R-mediated signalling. (a–c) MEFs knockout for either ß-arr isoform (a) or MEF WT (b) and HEK293T (HEK) (c) transfected with isoform-specific ß-arr2-encoding plasmid (+ß2), siRNA (-ß2) or respective controls (M), were serum starved and stimulated with IGF-1 (50 ng/ml) for 0–60 min. Lysates were analysed by WB for levels of phosphorylated (p) -IGF-1R, -AKT, -ERK, alongside total ERK and AKT, and GAPDH as a loading control (left panels). Late (30 and 60 min) ERK phosphorylation levels were quantified by densitometry, normalized to GAPDH and displayed as fold change from unstimulated level (graphs, right panel). Values indicate mean±s.e.m. from three independent experiments. Statistical analysis (two-tailed t-test): changes of IGF-1-dependent late pERK induced by ß-arr modulation (KO, +, -) compared with their respective WT or M (empty vector/non-target siRNA) control, *P<0.05, **P<0.01, ***P<0.001.

Fig 5: Representative images of HPS and IHC stainings in lung ADC and SCC samples. Automated IHC was performed on sections of the in-house TMA using antibodies that recognise beta-arrestin-1-2 (ARRB1-2), the commonly used ADC markers (TTF1, NAPSA, KRT7) and SCC markers (KRT5-6 and p63). DAB-based visualisation was used to assess protein expression. For each sample, a haematoxylin/phloxine/saffron (HPS)-stained slide is shown