Abstract 4913: Investigation of the in vitro differentiation ability of hybrid cell clones derived from spontaneous cell fusion events between murine breast cancer cells and murine mesenchymal stem cells.
Authors: Mohr Marieke , Zaenker Kurt S. , Dittmar Thomas 
Published: August 2014

We have previously shown that murine breast cancer cell lines are capable of acquiring malignant attributes through cell fusion with stem cell lines in vitro. Hybrid cell clones emerged from spontaneous fusion events in a co-culture model showed an increased resistance against chemotherapeutic substances together with a higher proliferation rate and genetic alterations compared to their parental cell lines. Since solid tumors, including breast cancer, have pronounced heterogeneity of cell populations, cell fusion between cancer cells and tumor infiltrating immune cells as well as stem cells is one mechanism how tumor cells could acquire new properties.

With relation to the importance of cell fusion in tumor heterogeneity and progression the objective of this study was to characterize and investigate if hybrid cell clones arised from spontaneous fusion events between hygromycin resistant murine 67NR-Hyg mammary carcinoma cells and puromycin resistant murine bone marrow derived stem cells (BMDCs) from Tg(GFPU)5Nagy/J mice to maintain their ability to differentiate into the neural and osteogenic lineage. Dual hygromycin/puromycin resistant mBMDC/67NRHyg cells originated by cell fusion were confirmed by a dual drug selection procedure and PCR analysis to examine an overlap of parental markers. BMDCs are generally defined as self-renewable, multipotent progenitor cells with the ability to differentiate into several mesenchymal lineages. Differentiation was performed by cultivating the cell clones and parental cell lines under appropriate conditions to an established neural and osteogenic differentiation protocol, respectively.

Our results revealed through molecular and biochemical analyses that hybrid cell clones and parental cell lines were positive for neuronal as well as osteogenic markers. Differentiation of hybrid cell clones into the osteogenic lineage was associated with expression of osteocalcin, bone sialoprotein II and collagen type I alpha 1 and increasing alkaline phosphatase activity, while differentiation into neuronal lineage was concomitant with expression of neurofilament M, GAD67 and class III beta-tubulin. In conclusion, our data show that hybrid cell clones are able to differentiate into specialized cells from both osteogenic and neuronal lineages. These stem cell properties indicate that cell clones derived from cell fusion events maintain abilities of the parental cell lines.

Citation Format: Marieke Mohr, Kurt S. Zaenker, Thomas Dittmar. Investigation of the in vitro differentiation ability of hybrid cell clones derived from spontaneous cell fusion events between murine breast cancer cells and murine mesenchymal stem cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4913. doi:10.1158/1538-7445.AM2013-4913