Abstract B76: Novel human 3D in vitro invasion model identifies tumor and stroma heterogeneity in squamous cell carcinoma

Abstract

Abstract 3D in vitro skin models are valuable research tools to investigate normal keratinocyte as well as skin carcinoma cell interaction with dermal fibroblasts. Currently, the models lack either a structured vital human extracellular matrix or long-term stability and longevity. Therefore, we aimed at a new 3D in vitro skin model for normal human epidermis and tumorigenic stages of skin cancer. This model is based on dermal equivalents containing a highly structured cell-derived matrix (CDM) produced by human dermal fibroblasts. First, we show that the CDM dermal equivalent supports a high structural integrity of the skin model and maintains a vital epidermis for six months. The epidermis is well-stratifying and differentiates in a regular orthokeratotic pattern. Transmission electron microscopy reveals ultrastructural entities as basement membranes, hemidesmosomes, desmosomes, keratohyalin granulae and lamellar bodies. In line, the molecular differentiation markers are properly distributed. Second, five non-tumorigenic and tumorigenic HaCaT keratinocyte variants are tested for their proliferation, differentiation and invasion capacities. After four weeks of co-cultivation the tumorigenic HaCaT variants show hyperproliferative epithelia and lose the capability of an ordered stratification and differentiation. Furthermore, they destroy the basement membrane as well as the extracellular matrix and invade the dermal equivalent. Moreover, seven squamous cell carcinoma (SCC) cell lines were co-cultivated with the CDM dermal equivalent. All SCC cells form hyperproliferative epithelia that heavily invade the extracellular matrix. Remarkably, the epithelia are individually distinct for their invasion and differentiation capacity. Thus, the CDM-based skin cancer model is suitable for demonstrating the heterogeneity of SCC tumors and their interaction with the microenvironment. In conclusion, the CDM model for normal skin and tumorigenic keratinocytes provides a novel tool to investigate keratinocyte-fibroblast interactions and microenvironment modulations during SCC development. Therefore, this system will provide further insights into mechanistic processes and the interaction of SCCs with their tumor microenvironment. Citation Format: Manuel Berning, Petra Boukamp. Novel human 3D in vitro invasion model identifies tumor and stroma heterogeneity in squamous cell carcinoma. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B76. doi:10.1158/1538-7445.CHTME14-B76