Characterization of a panel of mouse primary cell lines from Myc-driven mammary gland tumours and lung metastasis derived from them

These cells have low metastatic capacity. “Myc310” is also a tumour cell line generated from one of the MMTV-Myc tumours, but which has higher metastatic capacity and forms visible metastatic lesions in the lung. To generate models with high metastatic capacity, tumour cells were isolated from the lungs of mice bearing mammary gland tumours generated by ectopic injection of Myc310 cells into the fat pad. These cell lines were named “LM1”, “LM2” and “LM3”.

LMs cells were further injected in the fat pads of mice to generate mammary gland tumours. LMs cells showed higher metastatic capacity than Myc310 cells. Tumour cell lines isolated from the lungs of mice bearing LM1, LM2 or LM3 mammary gland tumours were named “LM1-LM”, “LM2-LM”, “LM3-LM”.

We have demonstrated that that the metastatic cell lines, Myc310, LM and LM-LM are more dependent on extracellular cysteine/cystine to survive than non-metastatic MYAZ cell lines. We therefore performed transcriptomics of some of the generated cell lines in control and cysteine/cystine deprived conditions. To generate a non-tumourigenic control for in vitro experiments and analysis, normal mammary gland epithelial cells were immortalized by ectopic expression of p53DN and E1A and named “iMMEC” cell line (immortalized mouse mammary epithelial cells).

To model the event during acute induction of c-MYC overexpression, we generated the “iMMEC+MYC”, iMMECs via transducing with a doxycycline inducible c-MYC construct.