Proteomic analysis to examine the functional consequences of intratumor heterogeneity

To examine the functional consequences of intratumor heterogeneity, subclonal populations (SCPs) were derived from the MDA-MB-468 triple-negative breast cancer cell line. Characterization of these SCPs revealed considerable variation in SCP tumor forming capacity with SCP #32 (SCP32) having an exceptional high tumor forming capacity. To investigate the proteomic differences between tumors of SCP32 and other SCPs, in TMT1, isobaric tandem mass tag (TMT) labeling combined with LC-MS/MS (TMT-MS) was performed on tumors of SCP03, SCP29 and SCP32 (n = 3 each) collected at 2 months post transplantation. In TMT2, isobaric tandem mass tag (TMT) labeling combined with LC-MS/MS (TMT-MS) was performed on tumors of the parental MDA-MB-468 cell line (n = 2), and both barcoded and non-barcoded versions SCP29 and SCP32 (two each) collected at 2 months post transplantation.