Identification of DEGs in lung cancer cells with the treatment of fluoxetine
To determine the effects of fluoxetine on lung cancer cells, we analyzed the RNA-seq data of H460 lung cancer cells with the treatment of fluoxetine. A total of 1,028 genes were identified with a threshold of P < 0.05. The top up- and down-regulated genes were shown by the heatmap and volcano plot (Fig. 1). The top ten DEGs were listed in Table 1.
Enrichment analysis of DEGs in lung cancer cells with the treatment of fluoxetine
To further understand the molecular mechanisms of fluoxetine treated lung cancer cells, we performed the KEGG and GO analyses (Figure 2). We identified the top ten KEGG items, including “Lysosome”, “Autophagy – animal”, “Phagosome”, “Steroid biosynthesis”, “Fatty acid metabolism”, “Epithelial cell signaling in Helicobacter pylori infection”, “Terpenoid backbone biosynthesis”, “Collecting duct acid secretion”, “Biosynthesis of unsaturated fatty acids”, and “Circadian rhythm”. We also identified the top ten biological processes of GO enrichment, including “steroid metabolic process”, “macroautophagy”, “sterol metabolic process”, “organic hydroxy compound biosynthetic process”, “secondary alcohol metabolic process”, “steroid biosynthetic process”, “cholesterol metabolic process”, “sterol biosynthetic process”, “cholesterol biosynthetic process”, and “secondary alcohol biosynthetic process”. We identified the top ten cellular components of GO enrichment, including “vacuolar membrane”, “lysosomal membrane”, “lytic vacuole membrane”, “late endosome”, “vacuolar lumen”, “primary lysosome”, “azurophil granule”, “lysosomal lumen”, “proton−transporting V−type ATPase complex”, and “proton−transporting V−type ATPase, V1 domain”. We identified the top ten molecular functions of GO, including “active transmembrane transporter activity”, “secondary active transmembrane transporter activity”, “active ion transmembrane transporter activity”, “proton transmembrane transporter activity”, “ATPase−coupled transmembrane transporter activity”, “amino acid transmembrane transporter activity”, “ATPase−coupled ion transmembrane transporter activity”, “ATPase activity, coupled to transmembrane movement of ions, rotational mechanism”, “proton−transporting ATPase activity, rotational mechanism”, and “pyrophosphate hydrolysis−driven proton transmembrane transporter activity”.
PPI network and Reactome analyses
To explore the potential relationship among the DEGs, we constructed the PPI network by using 869 nodes and 4,381 edges. The combined score > 0.2 was set as a cutoff by using the Cytoscape software. Table 2 indicated the top ten genes with the highest scores. The top two significant modules were presented in Figure 3. We further analyzed the PPI and DEGs with a Reactome map (Figure 4) and identified the top ten biological processes including “Activation of gene expression by SREBF (SREBP)”, “Regulation of cholesterol biosynthesis by SREBP (SREBF)”, “Cholesterol biosynthesis”, “Metabolism of steroids”, “DNA strand elongation”, “Insulin receptor recycling”, “Amino acids regulate mTORC1”, “G1/S-Specific Transcription”, “PPARA activates gene expression”, and “Regulation of lipid metabolism by PPARalpha” (Supplemental Table S1).