An experimental model for studying the desmoplastic response to tumor invasion

Cancer-associated fibroblasts from invasive breast cancer have an attenuated capacity to secrete collagens

Normal fibroblasts produce extracellular matrix (ECM) components that form the structural framework of tissues. Cancer-associated fibroblasts (CAFs) with an activated phenotype mainly contribute to ECM deposition and construction of cancer masses. However, the stroma of breast cancer tissues has been shown to be more complicated, and the mechanisms through which CAFs influence ECM deposition remain elusive. In this study, we found that the activated fibroblast marker α-smooth muscle actin (α-SMA) was only present in the stroma of breast cancer tissue, and the CAFs isolated from invasive breast cancer sample remained to be activated and proliferative in passages. To further assess the difference between CAFs and normal breast fibroblasts (NFs), MALDI TOF/TOF‑MS was used to analyze the secretory proteins of primary CAFs and NFs. In total, 2,903 and 3,023 proteins were identified. Mass spectrum quantitative assay and data analysis for extracellular proteins indicated that the CAFs produce less collagens and matrix-degrading enzymes compared with NFs. This finding was confirmed by western blot analysis. Furthermore, we discovered that reduced collagen deposition was present in the stroma of invasive breast cancer. These studies showed that although CAFs from invasive breast cancer possess an activated phenotype, they secreted less collagen and induced less ECM deposition in cancer stroma. In cancer tissue, the remodeling of stromal structure and tumor microenvironment might, therefore, be attributed to the biological changes in CAFs including their protein expression profile.

Prognostic significance of the expression of MUC1 and collagen type IV in advanced gastric carcinoma

Background

Scirrhous gastric carcinoma is characterized by excessive deposition of collagen in the stroma. However, the clinical significance of this fibrosis of the stomach has not been clarified. The aim of this study was to examine the fibrotic mechanism in several histological types of gastric carcinoma, and the combination of MUC1 and collagen type IV as a possible predictor of patient survival.

Methods

One hundred and two paraffin-embedded specimens of gastric carcinoma were examined by immunohistochemical staining using monoclonal antibodies against collagen type IV and MUC1.

Results

Collagen type IV-positive expression was significantly associated with depth of wall penetration (P = 0·025) and stage (P = 0·023). There was a significant relationship between MUC1-positive expression and interstitial collagen type IV-positive expression (P = 0·035). Survival was shorter for patients with the combination of MUC1-positive expression and interstitial collagen type IV-negative expression than for those with other expression patterns.

Conclusion

In patients with differentiated-type advanced gastric carcinoma, the combination of MUC1-positive and interstitial collagen type IV-negative expression may be a marker of unfavourable prognosis.

Evaluation of the efficacy of potential antineoplastic drugs on tumour metastasis by a computer-assisted image analysis

Computerised image analysis, performed on histological sections of (C57BL6/N) mouse lungs that had been intravenously (i.v.) injected with B16-F10 melanoma cells was used to develop a novel method to quantify the efficacy of potential antineoplastic drugs. This procedure allowed the evaluation of the rate of inhibition of growth and the anti-invasive capability of new molecules, thus resulting in more accurate data than that obtained from common macroscopical counting of surface metastatic foci. Several morphological parameters can be measured by this method: the percentage of tissue area occupied by metastases, which accounts for tumour implantation into the organ; the growth index, related to the size of the metastases, and the invasion index, related to the frequency of foci. These morphometric data were found to be correlated to the levels of lung hydroxyproline and transglutaminase activity, well known markers of tumour invasion and cell differentiation, respectively. The main objective of this computerised procedure was to evaluate how the tumour cell is affected in the host by the drug under investigation. The use of the method is exemplified by an analysis of the antitumour activity of some methylxanthines.