Alterations in SCAI Expression during Cell Plasticity, Fibrosis and Cancer

Suppressor of cancer cell invasion (SCAI) has been originally characterized as a tumor suppressor inhibiting metastasis in different human cancer cells, and it has been suggested that SCAI expression declines in tumors. The expression patterns and role of SCAI during physiological and pathophysiological processes is still poorly understood. Earlier we demonstrated that SCAI is regulating the epithelial-mesenchymal transition of proximal tubular epithelial cells, it is downregulated during renal fibrosis and it is overexpressed in Wilms' tumors. Here we bring further evidence for the involvement of SCAI during cell plasticity and we examine the prognostic value and expression patterns of SCAI in various tumors. SCAI prevented the activation of the SMA promoter induced by angiotensin II. SCAI expression decreased in a model of endothelial-mesenchymal transition and increased during iPS reprogramming of fibroblasts. During renal fibrosis SCAI expression declined, as evidenced in a rat model of renal transplant rejection and in TGF-β1 overexpressing transgenic mice. High expression of SCAI correlated with better survival in patients with breast and lung cancers. Intriguingly, in the case of other cancers (gastric, prostate, colorectal) high SCAI expression correlated with poor survival of patients. Finally, we bring evidence for SCAI overexpression in colorectal cancer patients, irrespective of stage or metastatic status of the disease, suggesting a diverse role of SCAI in various diseases and cancer.