Effect of Laminin on the Intrinsic Chemoresistance of Pancreatic Cancer Cell

  Objective  To determine the effect of laminin (LN) on the intrinsic chemoresistance of pancreatic cancer and whether such effect is mediated by LN-induced focal adhesion kinase (FAK) phosphorylation and subsequent downstream signal pathway.

  Methods  The effect of LN on gemcitabine (Gem) -induced cytotoxicity and apoptosis in pancreatic cancer cell line AsPC-1 cells were determined by MTT assay, clonogenic assay and apoptosis analysis. The effect of LN on the expression and phosphorylation of FAK, Akt, and ERK1/2 were detected by Western blotting. The changes in the effects of LN in AsPC-1 cells were explored by FAK phosphorylation inhibition through focal adhesion kinase-related non-kinase (FRNK) overexpression or specific FAK phosphorylation inhibitor PF-573, 228.

  Results  LN decreased Gem-induced cytotoxicity and apoptosis in AsPC-1 cells. After Gem treatment for 72 h, the viability was 57.71%±6.08% and the colony number was 55.33±5.01 on LN, while the viability and the colony number on plastic were 36.65%±4.14% and 31.43±4.62, respectively (both P < 0.05). The Annexin V positivity of AsPC-1 cells on LN (41.00%±5.46%) was significantly lower than that on plastic (55.70%±3.44%) (P < 0.05). Moreover, LN induced FAK and Akt phosphorylation in a time-dependent manner and increased the levels of survivin and pBad (pS136). Specific inhibition of LN-induced FAK phosphorylation by either FRNK overexpression or PF-573, 228 suppressed the effect of LN on AsPC-1 cells. PF-573, 228 increased Gem-induced apoptosis in AsPC-1 cells from 26.77%±0.49% to 38.53%±2.83% on LN (P < 0.05).

  Conclusions  LN contributes to the increased intrinsic chemoresistance of pancreatic cancer cell to Gem, which may be achieved through the regulation of FAK, Akt, and Bad phosphorylation and survivin expression. Targeted FAK inhibitors may be a promising way to enhance chemosensitivity in pancreatic cancer.