Polyethyleneimine

Fluorescence microscopy was carried out as described previously [15 (link),60 (link)] using the following filter cubes: F400 (excitation: 390–410 nm; dichroic mirror: 505 nm; emission: 510–550 nm), F425 (excitation: 422–432 nm; dichroic mirror: 600 nm; emission: 610 long pass), F480 (excitation: 470–495 nm; dichroic mirror: 505 nm; emission: 510–550 nm), and F565 (excitation: 545–580 nm; dichroic mirror: 600 nm; emission: 610 nm long pass). The cells were seeded and imaged in FluoroDish cell culture dishes (World Precision Instruments, Hertfordshire, UK; FD-35) precoated with 25 μg/mL polyethyleneimine (MP Biomedicals, 195444) [46 (link)], and cellSens Dimension software (version 2.1) (Olympus Belgium) was used for image acquisition and analysis.

2′3′-cGAMP (tlrl-nacga23-02) was purchased from InvivoGen. Ibrutinib (BTK inhibitor; no. S2680), PF-562271 (FAK inhibitor; no. S2890), PP2 (Src inhibitor; no. S7008), saracatinib (Fyn inhibitor; no. S1006), amuvatinib (c-Kit inhibitor; no. S1244), ruxolitinib (Jak1/2 inhibitor; no. S1378), alectinib (ALK inhibitor; no. S2762), gefitinib (EGFR inhibitor; no. S1025), AZD9291 (EGFR inhibitor; no. S7297), and R406 (Syk inhibitor; no. S2194) were obtained from Selleck. Polyethyleneimine (PEI; no. 195444) was purchased from Mpbio, and the transfection procedure was as previously described (16 (link), 33 (link)). Lipofectamine 2000 (no. 11668019) was obtained from Invitrogen. Antibodies against EGFR (no. 4267), GFP (no. 2956), phospho-Syk (Tyr525/526) (no. 2710), Syk (no. 13198), tubulin (no. 2146), and actin (no. 3700) were from Cell Signaling, and hemagglutinin (HA) antibody (ab18181) was purchased from Abcam. STING antibody (A3575) and GST (AE001) antibodies were obtained from Abclonal Technology.