Fig. 5

H19 lncRNA induces the immortalization of recipient cells. A FACS-sorted tdTomato-positive cells from the lung (normal AT2 cells) of 4-week-old ST mice (n = 20), MPG-ST mice (n = 20), or MPG-ST-iDTR mice (n = 20) were co-cultured with M-MDCs (as described before) or their exosomes and then transplanted into wild-type (WT) recipient mice. Tumor incidence, described as transplantation sites with tumors/transplanted mice amount (ratio), was measured at 18 weeks after transplantation. n = number of mice. B The tdTomato-positive AT2 cells were sorted from the lung metastasis of MPG-ST-iDTR mice (without DT injection) at 12 weeks, 14 weeks, 16 weeks or 18 weeks (n = 5/group). The RNA levels of H19 lncRNA were determined by qRT-PCR and normalized to U6 snRNA. n = number of mice. Data presented are the mean of triplicate experiments. Error bars indicate standard deviation. C Morphology of 6th passage primary AT2 cells from 12 to week-old MPG-ST-iDTR mice (left panel) or 10th passage primary AT2 cells from lung metastases of 18-week-old MPG-ST-iDTR mice (right panel). D Cumulative population doublings (CPDs) show the growth kinetics of the primary AT2 cells from 12-week-old MPG-ST-iDTR mice (normal AT2) or primary AT2 cells from lung metastases of 18-week-old MPG-ST-iDTR mice (immortal AT2). E Expression of telomerase reverse transcriptase (TERT) in samples described below was detected and quantified. GAPDH was used as a control. Data presented are the mean of triplicate experiments. Error bars indicate standard deviation. F Telomerase activity of samples described below was determined by telomeric repeat amplification protocol assay. As a control, heat-inactivated samples were also assayed (right lane). Samples of E and F lane 1: normal AT2 cells from ST mice; Lane 2: normal AT2 cells from MPG-ST mice; Lane 3: normal AT2 cells from MPG-ST-iDTR mice; Lane 4: normal AT2 cells from ST mice co-cultured with exosomes from M-MDCs; Lane 5: normal AT2 cells from MPG-ST mice co-cultured with exosomes from M-MDCs; Lane 6: normal AT2 cells from MPG-ST-iDTR mice co-cultured with exosomes from M-MDCs; Lane 7: immortal AT2 cells. Abbreviations: MPG, MMTV–PyMT-Green; MGP-ST, MPG/Sftpc-Tomato; MPG-ST-iDTR, MGP/ST/Cre-inducible diphtheria toxin receptor