FAM64A regulates the malignant phenotype and tumor microenvironment of non-small cell lung cancer by activating the JAK/STAT3/PDL1 axis

Non-small cell lung cancer (NSCLC) is a life-threatening disease that still lacks effective targeted treatment. Family with sequence similarity 64, member A (FAM64A) is dysregulated in different malignancies and participates in the cancer progression. To address the role of FAM64A in NSCLC. The FAM64A expression was detected by reverse transcription quantitative polymerase chain reaction and western blotting. Short-hairpin RNAs (shRNAs) against FAM64A were transfected into A549 and H460 cells. The role of FAM64A in vitro was evaluated by cell counting kit-8, transwell, enzyme-linked immunosorbent assay, immunofluorescence and western blotting. In vivo role of FAM64A was addressed in xenografted mice using immunohistochemistry and western blotting. FAM64A was upregulated in NSCLC that predicted a dismal prognosis for NSCLC patients. Knockdown of FAM64A diminished cell viability, invaded cell numbers, the Vimentin expression and the concentrations of TGF-β and IL-10, but fostered the E-cadherin expression and the concentrations of IL-2 and IFN-γ in NSCLC cells. Mechanistically, silencing of FAM64A declined the expression of JAK/STAT3/PD-L1 pathway, which was restored with the application of RO8191, an activator of JAK/STAT3 pathway. The inhibitory role of FAM64A knockdown in NSCLC cell proliferation, invasion, EMT and immune escape was inverted by the management of RO8191. In vivo, knockdown of FAM64A reduced tumor size and weight, the level of Vimentin and PD-L1, and the expression of JAK/STAT3/PD-L1 pathway, but enhanced the IFN-γ level. Upregulation of FAM64A promoted proliferation, invasion, EMT and immune escape through activating JAK/STAT3/PD-L1 axis.