Promotion of the occurrence of endometrioid carcinoma by S100 calcium binding protein P

Background

Endometrial cancer, one of the most common malignant tumors, is a serious threat to women’s health. Endometrial hyperplasia is a precursor of endometrial cancer. S100 calcium binding protein P (S100P) has been found to play important roles in many types of cancer. The present study aimed to investigate the expression of S100P in endometrial cancer and its precursor lesions, and to explore the possible mechanisms.

Methods

We collected paraffin sections of normal endometrium, simple and complex non-atypical hyperplasia, atypical hyperplasia, and endometrioid carcinoma. The expression of S100P in endometrial cancer and its precancerous lesions was observed using immunohistochemistry. We also cultured primary endometrial cells and endometrial cancer cell lines (Ishikawa and RL95–2), and observed the expression of S100P in these cells. Laser confocal microscopy was used to observe the co-localization of S100P and its interacting protein Ezrin in RL95–2 cells. We employed lentiviruses to knockdown and overexpress S100P and then detected the F-actin distribution and cell invasion using phalloidin staining and Transwell assays.

Results

There was a gradual increase in the S100P signal as the disease progressed from normal endometrium and simple non-atypical hyperplasia, to complex non-atypical hyperplasia, atypical hyperplasia, and then to endometrial cancer. S100P was mainly distributed in the cytoplasm and co-localized with Ezrin in endometrial cancer cells. After knocking down S100P, F-actin aggregated in the nucleus or to the local cell membrane. Furthermore, knockdown of S100P in Ishikawa cells decreased their cell invasion capability. Meanwhile, S100P overexpression in endometrial stromal cells increased cell invasion.

Conclusions

These data suggested that S100P might be involved in the occurrence and development of endometrial cancer via interaction with Ezrin and re-organization of F-actin to promote cell invasion.

S100P is associated with proliferation and migration in nasopharyngeal carcinoma

In the present study, the function of S100 calcium binding protein P (S100P) in the C666-1 nasopharyngeal carcinoma (NPC) cell line was examined. The levels of S100P protein in NPC tissues were analyzed using immunohistochemistry, and small interfering RNA silenced S100P expression in C666-1 cells. Subsequently, cell proliferation, colony formation, migration and wound-healing assays were performed in order to assess whether the knockdown of S100P was able to influence the biological behavior of C666-1 cells. The expression levels of the receptor for advanced glycation end products (RAGE) were analyzed using a western blot following the inhibition of S100P. The immunohistochemistry results revealed that S100P was elevated in expression in 45/78 (57.7%) of patients with NPC, as compared with 5/30 (16.7%) of patients with benign inflammation. The S100P protein levels correlated with the rates of proliferation and migration in C666-1 cells. Additionally, reduced S100P expression levels altered a series of intracellular events, including the downregulation of epidermal growth factor receptor, cluster of differentiation (CD) 44, matrix metalloproteinase (MMP) 2 and MMP9 protein expression. In addition, RAGE expression was downregulated in the S100P silenced C666-1 cells, as detected by western blot analysis. These data suggest that S100P is important during the development and progression of nasopharyngeal cancer. Therefore, S100P may provide a novel treatment target for NPC.