Fig. 1

The IL-6 and IL-8 signal transduction pathways. a The binding of IL-6 to its receptor IL-6R leads to homodimerization of gp130, resulting in phosphorylation of JAKs which further phosphorylates and activates STAT3. The activated STAT3 binds with other STAT proteins (STATs) to form homodimers or heterodimers, which facilitates the transcription of diverse downstream genes. b IL-8 binds to its receptor CXCR1 or CXCR2 (belonging to GPCR superfamily), activating G protein. The G protein subunits activate PLC and PI3K, which further lead to the phosphorylation of PKC and AKT, respectively. Besides, the Rho-GTPase family and non-receptor tyrosine kinases (such as Src and FAK) can be activated by IL-8 signaling. And activated MAPK signaling cascade (Raf-1/MEK/ERK) also transduces the IL-8 stimuli