Figure 1: Culture of lung cancer cell lines QUDB, A549, and HFLF in the appropriate medium.

Figure 2: Cell viability by the MTT assay.

Cell viability of control or treated QUDB, A549, and HFLF was assessed 48 h post-treated by the MTT assay (n = 3. ***p < 0.001). A: Detection of Cell viability in QUDB, A549, and HFLF cell lines after treatment with ketanserin. B: Detection of Cell viability in QUDB, A549, and HFLF cell lines after treatment with tropisetron

Figure 3: Detection of apoptosis and necrosis in lung cancer cell lines QUDB, A549, and HFLF after treatment with tropisetron and ketanserin by flow cytometry.

Figure 4: Detection of apoptosis in lung cancer cell lines QUDB after treatment with tropisetron and ketanserin by immunofluorescence staining.

Figure 5: Detection of apoptosis in lung cancer cell lines A549after treatment with tropisetron and ketanserin by immunofluorescence staining.

Figure 6: Schematic illustration of the role of HTR2A signaling pathway on cancer. Serotonin signaling promotes tumor proliferation and inhibits apoptosis of tumor cells via HTR2A and activates MAPK and PI3K/Akt signaling. Ketanserin as the antagonist of HTR2A can block this pathway.