The Impact of Cysteine-Rich Intestinal Protein 1 (CRIP1) on Thyroid Carcinoma.

Background/aims: CRIP1 (cysteine-rich intestinal protein 1) has been found in several tumor types; however, its prognostic impact and role in cellular processes, particularly in thyroid carcinoma, are still unclear.

Methods: To elucidate the prognostic impact of CRIP1, we analyzed tissues from 58 primary invasive thyroid carcinomas using immunohistochemistry. Western blotting was performed to investigate CRIP1 protein expression in the thyrocyte cell line Nthy-ori 3-1 and four different thyroid carcinoma cell lines, K1, TPC-1, TT, and SW579. Endogenous expression of CRIP1 was suppressed using a siRNA (si-CRIP1). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to investigate cell viability. Flow cytometric analysis was used to detect cell cycle progression and cell apoptosis. The effects of silencing CRIP1 on cell migration and invasion were detected using the transwell assay.

Results: The immunohistochemistry results showed that CRIP1 was overexpressed in thyroid carcinoma. CRIP1 expression was associated with tumor size, TNM stage, and lymphatic metastasis, but not with age, gender, and tumor location. In addition, the expression of CRIP1 in K1, TPC-1, TT, and SW529 cells was higher than that in the Nthy-ori 3-1 cells. The highest expression was observed in the SW579 and TT cells. Furthermore, silencing CRIP1 inhibited the proliferation, migration, and invasion of thyroid carcinoma cell lines SW579 and TT. We also found that silencing CRIP1 induced G1 arrest and apoptosis of thyroid carcinoma cell lines SW579 and TT.

Conclusion: In conclusion, CRIP1 acts as an oncogene in the cell proliferation, migration, and invasion processes of thyroid carcinoma. CRIP1 may serve well as an independent prognostic marker with significant predictive power for use in thyroid carcinoma therapy.