Porcupine expression is associated with the expression of S100P and other cancer-related molecules in non-small cell lung carcinoma.

The omicron-acyltransferase porcupine contributes to secretion and function of Wnt signaling molecules, which stimulate the expression of various cancer-related genes. Porcupine is also involved in the Wnt-induced cell signaling via beta-catenin in non-small cell lung carcinoma (NSCLC) cells. Herein, we report that the expression level of porcupine in human NSCLC tissues (n=89) positively correlates with the expression of several genes coding for cancer-related molecules such as beta-catenin, hypoxia-inducible factor-1alpha and jun B. However, the mRNA expression of porcupine was not generally increased in NSCLC compared to normal lung tissues. In NSCLC tissues we also found a positive correlation between the expression level of porcupine and the calcium-binding protein S100P, which contributes to initiation and invasion of cancer cells. Subsequent studies showed that the DNA hypomethylation with 5-aza-2'deoxycytidine increased the mRNA expression of S100P in NSCLC cells but did not alter that of porcupine. Silencing the expression of porcupine with small interfering (si)RNA reduced the expression of S100P in NSCLC cells, whereas silencing the expression of S100P with siRNA did not effect the level of Porcupine expression. In conclusion, besides DNA methylation processes, porcupine might regulate the expression of some cancer-related molecules including S100P in human NSCLC.