Expression of tissue inhibitor of matrix metalloproteinase-1 in human breast carcinoma

Proteomics analysis of serum from thymoma patients

Thymoma is the most common malignant tumor in thymic epithelial tumors (TETS). This study aimed to identify the changes in serum proteomics in patients with thymoma. Proteins were extracted from twenty patients with thymoma serum and nine healthy controls and prepared for mass spectrometry (MS) analysis. Data independent acquisition (DIA) quantitative proteomics technique was used to examine the serum proteome. Differential proteins of abundance changes in the serum were identified. Bioinformatics was used to examine the differential proteins. Functional tagging and enrichment analysis were conducted using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The string database was used to assess the interaction of different proteins. In all, 486 proteins were found in all samples. There were differences in 58 serum proteins between patients and healthy blood donors, 35 up-regulated and 23 down-regulated. These proteins are primarily exocrine and serum membrane proteins involved in controlling immunological responses and antigen binding, according to GO functional annotation. KEGG functional annotation showed that these proteins play a significant role in the complement and coagulation cascade and the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signal pathway. Notably, the KEGG pathway (complement and coagulation cascade) is enriched, and three key activators were up-regulated: von willebrand factor (VWF), coagulation factor v (F5) and vitamin k-dependent protein c (PC). Protein-protein interaction (PPI) analysis showed that six proteins ((VWF, F5, thrombin reactive protein 1 (THBS1), mannose-binding lectin-associated serine protease 2 (MASP2), apolipoprotein B (APOB), and apolipoprotein (a) (LPA)) were up-regulated and two proteins (Metalloproteinase inhibitor 1(TIMP1), ferritin light chain (FTL)) were down-regulated. The results of this study showed that several proteins involved in complement and coagulation cascades were up-regulated in the serum of patients.

Identification of alternatively spliced TIMP-1 mRNA in cancer cell lines and colon cancer tissue

TIMP-1 is a promising new candidate as a prognostic marker in colorectal and breast cancer. We now describe the discovery of two alternatively spliced variants of TIMP-1 mRNA. The two variants lacking exon 2 (del-2) and 5 (del-5), respectively, were identified in human cancer cell lines by RT-PCR. The del-2 variant was, furthermore, detected in extracts from 12 colorectal cancer tissue samples. By western blotting additional bands of lower molecular mass than full-length TIMP-1 were identified in tumor tissue, but not in plasma samples obtained from cancer patients. The two splice variants of TIMP-1 may hold important clinical information, and either alone or in combination with measurement of full-length TIMP-1 they may improve the prognostic and/or predictive value of TIMP-1 analyses.

Concentrations of TIMP1 mRNA splice variants and TIMP-1 protein are differentially associated with prognosis in primary breast cancer

BACKGROUND

TIMP-1 protein is a prognostic factor for recurrence-free and overall survival (OS) time in breast cancer. We evaluated the prognostic value of TIMP1 mRNA and a novel TIMP1 mRNA splice variant in 1301 primary breast cancer patients.

METHODS

We measured mRNA transcripts of full-length TIMP1 (TIMP1-v1) and the novel splice variant lacking exon 2 (TIMP1-v2) by use of real-time RT-PCR in frozen primary tumor samples. Transcript concentrations are correlated with histomorphological and biological factors, TIMP-1 protein, and distant metastasis-free survival (MFS) and OS time.

RESULTS

TIMP1-v1 and TIMP1-v2 alone were not informative with respect to predicting prognosis. However, the PCR assay designed to measure the combination of v1 + v2 showed that high concentrations of this combination were associated with good prognosis. In Cox multivariate regression analysis, which also included the traditional prognostic factors, increasing concentrations were independently associated with prolonged MFS (P = 0.004) and OS (P = 0.048). Including TIMP-1 protein and TIMP1-v1+v2 mRNA together in the multivariate model revealed that protein and mRNA were both independently associated with prognosis, with hazard ratios pointing in opposite directions.

CONCLUSION

High concentrations of TIMP1-v1+2 mRNA are associated with good prognosis in patients with primary breast cancer. Since high concentrations of TIMP-1 protein are associated with poor prognosis, the presence of possible posttranscriptional mechanisms requires further investigation.