Archives

  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2020-03
  • 2020-07
  • 2020-08
  • 2021-03
  • br beginning of week and continued

    2019-09-16

    
    beginning of week 5, and continued for the rest of the 10-week study. Mice receiving either 25 ng or 100 ng per injection of 24R,25(OH)2D3 survived longer than mice injected with vehicle alone. 6/8 and 7/8 animals in the 25 ng and 100 ng groups, respectively, survived until harvest, while only 3/8 animals survived in the control group [Fig. 2A]. Animals in the control group also started dying earlier (at day 38) than animals given 24R,25(OH)2D3 (day 56) [Fig. 2B]. Both 25 ng and 100 ng treated tumors exhibited CH 223191 lower percent increase in size com-pared to vehicle-treated mice. Tumors in both 24R,25(OH)2D3 treated groups achieved approximately 500% of their original volume, while vehicle-treated tumors grew to approximately 1000% of their original volume [Fig. 2C]. Tumors in mice given 25 ng 24R,25(OH)2D3 reached volumes of approximately 400 mm3 at harvest, roughly 80% the size of the tumors in vehicle-treated mice, which reached a volume of 500 mm3 on average. Tumors in mice given 100 ng showed an even steeper growth depression, reaching final volumes of 200 mm3 on average, roughly 40% of vehicle-treated tumors [Fig. 2D, E].
    A. Verma, et al. BBA - General Subjects xxx (xxxx) xxx–xxx
    (A) After 8 weeks, 3 animals from the vehicle group, 6 animals from the low-dose 24R,25(OH)2D3 group, and 7 animals from the 24R,25(OH)2D3 group survived out of an original n of 8. (B) Animals in the vehicle group had a statistically significant reduced survival rate as compared to animals in the low or high dose groups by the
    chi-squared logrank test for trend (P = 0.0433). (C) Tumor accretion rate was calculated by normalizing tumor volumes at each week to the original tumor volume calculated at week 2. (D) Animals given 24R,25(OH)2D3 showed a decreased rate of growth after vitamin D3 injections were begun at week 6 of the study. Statistics were done using a repeated-measures ANOVA test to compare between the vehicle, low, and high-dose groups within weeks. Purple squares □ indicate significance against the high-dose group, and blue open circles ○ indicate significance against the low-dose group. (E) After harvest, tumor volume was quantified using μCT analysis. Calculated caliper volumes and μCT-derived volumes were graphed together, and statistics were done using ANOVA with Tukey's correction. Bars that share a letter are not significant at α = 0.05. Both caliper measurements and μCT analyses showed statistically significant decreases in final tumor volume between the high-dose 24R,25(OH)2D3 group and the vehicle control; and μCT analysis showed a statistically significant difference between both the vehicle and the low-dose 24R,25(OH)2D3 group as compared to the high-dose 24R,25(OH)2D3 group. (F) Histology of the fourth mammary fat pad showed cells with a dense epithelial-like phenotype consistent with MCF7 morphology and previous MCF7 xenograft studies, bar 50 μm.
    [Fig. 2E]. Haematoxylin and eosin (H&E) staining revealed similar tumor morphology in tumors from each group [representative image, Fig. 2F].
    Metastatic burden was detected in animals by assessing individual organs for RFP expression using a fluorescent dissection microscope at harvest. Animals treated with 24R,25(OH)2D3 had a lower metastatic burden than vehicle-injected controls, with fewer organs that were positive for RFP-tagged MCF7 cells. Animals treated with 25 ng 24R,25(OH)2D3 had, on average, 1–2 incidences of metastasis/animal, while 100 ng treated animals averaged 0–1 metastatic incidence per animal. Control group animals averaged 3–4 incidences of metastasis per animal [Fig. 3A]. Animals treated with 24R,25(OH)2D3 also had fewer incidences of local and distant metastasis than control group animals, with animals injected with 25 ng 24R,25(OH)2D3 having fewer incidences of multiple lymph nodes, lung, and liver metastases. This effect was even greater in animals treated with higher doses of 24R,25(OH)2D3 (100 ng). These animals had fewer lymph node and lung metastases and no incidences of multiple lymph nodes or liver metastases [Fig. 3B]. Metastatic sites were characterized by round clusters of RFP-positive cells with defined edges, characteristic of MCF7 metastases [79] [Fig. 3C-E]. Morphology of metastatic sites was similar to the morphology of the primary tumor [Fig. 3F-H]. None of the ani-mals showed signs of hypercalcemia throughout the study or upon