Nonsteroidal anti-inflammatory drug sulindac sulfide suppresses structural protein Nesprin-2 expression in colorectal cancer cells.

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are well known for treating inflammatory disease and have been reported to have anti-tumorigenic effects. Their mechanisms are not fully understood, but both cyclooxygenase (COX) dependent and independent pathways are involved. Our goal was to shed further light on COX-independent activity.

Methods: Human colorectal cancer cells were observed under differential interference contrast microscopy (DICM), fluorescent microscopy, and micro-impedance measurement. Microarray analysis was performed using HCT-116 cells treated with sulindac sulfide (SS). PCR and Western blots were performed to confirm the microarray data and immunohistochemistry was performed to screen for Nesprin-2 expression. Micro-impedance was repeating including Nesprin-2 knock-down by siRNA.

Results: HCT-116 cells treated with SS showed dramatic morphological changes under DICM and fluorescent microscopy, as well as weakened cellular adhesion as measured by micro-impedance. Nesprin-2 was selected from two independent microarrays, based on its novelty in relation to cancer and its role in cell organization. SS diminished Nesprin-2 mRNA expression as assessed by reverse transcriptase and real time PCR. Various other NSAIDs were also tested and demonstrated that inhibition of Nesprin-2 mRNA was not unique to SS. Additionally, immunohistochemistry showed higher levels of Nesprin-2 in many tumors in comparison with normal tissues. Further micro-impedance experiments on cells with reduced Nesprin-2 expression showed a proportional loss of cellular adhesion.

Conclusions: Nesprin-2 is down-regulated by NSAIDs and highly expressed in many cancers.

General Significance: Our data suggest that Nesprin-2 may be a potential novel oncogene in human cancer cells and NSAIDs could decrease its expression.