Kindlin-2 induced by TGF-β signaling promotes pancreatic ductal adenocarcinoma progression through downregulation of transcriptional factor HOXB9

• Kindlin-2 is upregulated but HOXB9 is downregulated by TGF-β1 in PDAC cells.
• Kindlin-2 upregulates but HOXB9 downregulates TβRI in PDAC cells.
• Kindlin-2 and TGFβ signaling constitute a positive feedback loop that regulates PDAC progression.
• Enhanced expression of Kindlin-2 predicts a poor prognosis for PDAC patients.

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths with no effective therapeutics. Invasion and metastasis are the major characteristics of PDAC. However, mechanisms underlying PDAC invasion and metastasis are elusive. In this report, we found that Kindlin-2 is a target protein of transforming growth factor β (TGF-β) signaling and is upregulated by TGF-β1 in PDAC cells. TGF-β1-upregulated Kindlin-2 promotes PDAC cell growth, migration and invasion, whereas Kindlin-2 upregulates transforming growth factor receptor I (TβRI), a key component of TGF-β signaling. Thereby Kindlin-2 and TGF-β signaling constitute a positive feedback loop. Mechanistically, Kindlin-2 promotes PDAC progression by downregulation of HOXB9 and E-cadherin. For clinical relevance, enhanced expression of Kindlin-2 predicts a poor overall survival for PDAC patients. Gene expression levels of Kindlin-2, TGF-β, TβRI and HOXB9 are all correlated with the overall survival of PDAC patients in an Oncomine dataset. Taken together, our findings demonstrated that TGF-β1-induced Kindlin-2 expression promotes PDAC progression by downregulation of HOXB9 and E-cadherin.