The Tendon Biomarker Tenomodulin Is Expressed At Tenocyte Levels In Cancer Cells Derived From A Uterine Carcinoma (HeLa)
Kim J, Norman W, Qi J, Banes AN, Banes AJ. 14th Annual Conference of the North Carolina Tissue Engineering and Regenerative Medicine Society, Raleigh, NC, September 10, 2012.
Tenomodulin is a tenocyte biomarker used in tissue engineering, present in embryonic and adult cells. Although it is an accepted marker for tendon cells, its function is unknown. Recently, it has been shown that Tnmd exists in three isoforms, none of which are secreted. Results of a KO mouse model found a reduction in cell number in tendons. We hypothesized that Tnmd might be involved in cell cycle regulation, given cell numbers in tendon are reduced in the KO mouse and tenocytes treated with RNAi to Tnmd also reduced cell proliferation. HeLa cells were tested for Tnmd expression and were found to express Tnmd as highly as tenocytes. Cells were cultured in growth medium, split and plated on cover slips and paused in pro metaphase with 300 nM nocodazole for 16h, then released in serum-containing medium to restart the cells. Cells were collected in prometaphase, metaphase, anaphase and telophase and assessed for Tnmd localization and co-localization with a-tubulin for spindle fibers, ?-tubulin for centrioles and GFP-transfected Tnmd isoforms. Immunolocalization of Tnmd showed that antibody staining was peri-chromatin in prometaphase and metaphase, then at the tip of the chromosomes and around the chromosomes in anaphase and telophase. The biomarker, tenomodulin, is not specific to tendon and is found in cancer cells, such as the continuous cell line HeLa. Its functions may involve regulating the availability of chromatin via methylation and degradation. Tnmd also has an early role in tendon, likely as a cell cycle control protein regulating tenocyte fate.