Rab23 promotes squamous cell carcinoma cell migration and invasion via integrin β1/Rac1 pathway.

Rab23 was a member of Ras-related small GTPase family, which played a key role in the regulation of Shh signaling pathway. However, the function and regulatory mechanism of Rab23 in cutaneous squamous cell carcinoma was unknown. In this study, we found that the expression level of Rab23 was higher in moderately to poorly tumor differentiation tissue and non-exposed positions, and no statistically significant difference showed in Rab23 expression according to trauma/chronic disease, location on lips/ears, tumor size, gender, or age. Interestingly, we found that Rab23 RNAi suppressed cell invasion and Rab23 overexpression promoted cell invasion depended on GTP-bound form of Rab23. Inhibition of Rac1 activity or Rac1 silencing with siRNA fragment attenuated Rab23 promoted cells migration and invasion. Notably, we confirmed that Rab23 was co-localized with integrin β1 in cell membrane of Rab23 WT and Rab23 Q68L stable expression cells and Rab23 efficiently coprecipitated with integrin β1 and Tiam1 in a GTP-dependent manner. Further, integrin β1 siRNA interrupted the coprecipitation between Rab23 and Tiam1 and attenuated Rab23 promoted cells migration and invasion. Taken together, our results indicated that Rab23 promotes squamous cell carcinoma cells migration and invasion by regulating Integrin β1/Tiam1/Rac1 pathway.