Stromal impact on tumor growth and lymphangiogenesis in human carcinoma xenografts

Abstract

Squamous cell carcinomas (SCCs) arising in the oral cavity are associated with poor survival, mainly due to metastatic disease. In contrast, skin SCCs rarely metastasize and are usually curable. To study influence of tongue and skin stroma on cancer growth and induction of lymphangiogenesis, xenograft tumors of human carcinoma cells were established either in tongue or skin of BALB/c nude mice. Two oral and two skin SCC cell lines were used, as well as an endometrial adenocarcinoma cell line. Tongue tumors established from all cell lines were larger than corresponding skin tumors. Peritumoral lymphatic vessel density was up to five times higher in tongue than in corresponding skin tumors, and mRNA level of the lymphangiogenic growth factor vascular endothelial growth factor (VEGF)-C was twice as high in tongue tumors compared with corresponding skin tumors. Contrary to lymphatic vessel density, blood vessel density was higher in skin tumors than in tongue tumors. In a cohort of patient samples, lymphatic vessel density was found to be higher in tongue SCCs compared with skin SCCs, supporting a clinical relevance of our findings. Our results show that the tumor stroma has a profound impact on cancer growth and induction of lymphangiogenesis and angiogenesis. The difference in lymphatic vessel density between tongue and skin tumors may be important in directing metastatic potential of tumors arising in these organs.

S100A4 Expression in Xenograft Tumors of Human Carcinoma Cell Lines Is Induced by the Tumor Microenvironment

“…In a previous study using the same xenograft tumors, we found that the inflammatory infiltrate was more pronounced in tongue tumors compared with in the corresponding skin tumors for all three cell lines. Neutrophils were the predominant cell type in the inflammatory infiltrate, 15 and in the present study, stromal S100A4 staining was mainly seen in and surrounding cells with morphologic features similar to those of neutrophils and macrophages (data not shown).…”

“…Xenograft tumors of the various cell lines were established in the tongue or skin of BALB/c nude mice as previously described. 15 The mice were sacrificed after 5 to 28 days of tumor growth, and tumor tissue was either submerged in RNAlater (Sigma-Aldrich) or fixed in Zn-based fixative. 19 Tissue/tumor samples stored in RNAlater were dissected under a dissecting microscope and were divided into three different fractions: i) tumor, ii) stroma close to tumor (Ͻ0.5 mm from the tumor), and iii) stroma further away from the tumor (Ͼ0.5 mm from the tumor).…”

“…We previ- ously found that the various cell lines formed larger tumors and behaved more aggressively when they grew in tongue compared with in skin, irrespective of organ of origin of the cancer cells. 15 Tongue tumors showed, in contrast to skin tumors, an infiltrative growth pattern accompanied by increased proteolytic activity toward the invasive front. 16 Lymph node metastases were detected from some of the tongue tumors but not from any of the skin tumors.…”

“…16 Lymph node metastases were detected from some of the tongue tumors but not from any of the skin tumors. 15 Because S100A4 is reported to affect expression and activation of matrix metalloproteinases 17 and to promote invasion and metastasis of cancer cells, we hypothesized that this protein could be differentially expressed in tongue and skin tumors in our xenograft model. In the present study, we investigated the role of the tumor microenvironment for expression of S100A4 in tumor cells and the surrounding stroma.…”

Presence of tumour high-endothelial venules is an independent positive prognostic factor and stratifies patients with advanced-stage oral squamous cell carcinoma

“…Manual staining for HEVs, including evaluation of antibody specificity, were carried out as previously described (23,35). In brief, after rehydration, heat-induced antigen retrieval, and blocking steps, …”