The present study aimed to investigate the binding of circulating mucin 1 (MUC1) antibody with serum MUC1 antigen in stage IV breast cancer. Serum samples of 61 patients with stage IV breast cancer and 64 patients with early-stage breast cancer were collected. The anti‑MUC1 antibody (IgG) and MUC1 antigen (cancer antigen 15‑3; Ca15‑3) were detected using an indirect enzyme-linked immunosorbent assay (I‑ELISA) and ELISA, respectively. The MUC1 IgG affinity was detected using a urea degradation combining ELISA. Western blot analysis and an inhibition test were performed for verification of the binding of anti‑MUC1 IgG with MUC1 antigen, and their correlation was analyzed. The results showed that there was a negative correlation between anti‑MUC1 IgG and CA15‑3 antigen in stage IV breast cancer when positive CA15‑3 antigen and/or anti‑MUC1 IgG were selected (r=‑0.417; P=0.0044). The positive anti‑MUC1 IgG with positive Ca15‑3 antigen was more common in stage IV breast cancer, compared with early‑stage breast cancer (χ2=4.629; P=0.031), however, Ca15‑3 antigen positivity was higher in stage IV breast cancer, compared with early‑stage breast cancer (χ2=10.58; P=0.001). Anti‑MUC1 IgG was able to bind to the MUC1 antigen in stage IV breast cancer. No differences in the 8R-MUCPT inhibition ratio were found between the two groups (P=0.778), and there were no differences in the affinity of anti‑MUC1 IgG (P=0.873). In stage IV breast cancer, circulating anti‑MUC1 antibody was found to bind serum MUC1 antigen, although their compatibility was low. No significant difference was found in the affinity of the anti‑MUC1 antibody between stage IV breast cancer and early‑stage breast cancer.

No abstract

No abstract

Background Previous studies have published the promoting effect of serum and glucocorticoid-regulated kinase 1 (SGK1) in various malignant tumors. However, whether SGK1 promotes gastric cancer remains a mystery. Aims To clarify the function of SGK1 in gastric cancer and its potential regulatory mechanism. Study Design Cell culture study. Methods The SGK1-silenced model was generated in two gastric cancer cell lines and further evaluated their malignant behavior and susceptibility to cisplatin. The interaction between miR-15a-5p and SGK1 was evaluated by the luciferase reporter assay. The knockdown efficiency of SGK1 was confirmed by RT- qPCR and Western blot assays. Cell proliferation rate was assessed with CCK-8 assay, and flow cytometry was used to determine cell cycle progression and apoptosis. Results Western blot data displayed an elevated level of SGK1 in gastric cancer cell lines. Functionally, SGK1 deficiency suppressed gastric cancer cell proliferation ( P < .01) by acting on cell-cycle progression. Moreover, SGK1 deficiency suppressed cell invasion and migration of gastric cancer cells ( P < .01). Further, the silencing of SGK1 obviously suppressed cell proliferation and induced apoptosis of the cells after cisplatin treatment ( P < .01), indicating that SGK1 deficiency facilitated the chemosensitivity of these 2 gastric cancer cell lines to cisplatin. Mechanically, downregulation of SGK1 repressed the cytoplasm-to-nucleus translocation of NF-κB p65. Interestingly, we found that miR-15a-5p binds to the 3'UTR of SGK1, which was confirmed using luciferase activity assay ( P < .05). Moreover, the data suggested that SGK1 reversed the suppression effect of miR-15a-5p on gastric cancer cell migration ( P < .01). Conclusion Loss of SGK1 suppresses the malignant behavior of gastric cancer cells and increases cisplatin sensitivity by restraining the NF-κB signaling pathway. Moreover, SGK1 may exert an inhibitory effect in gastric cancer by being targeted by miR-15a-5p. Therefore, SGK1 may be a prospective target for future gastric cancer therapy.