Limits...
Enhancement of viability of radiosensitive (PBMC) and resistant (MDA-MB-231) clones in low-dose-rate cobalt-60 radiation therapy.

Falcão PL, Motta BM, de Lima FC, Lima CV, Campos TP - Radiol Bras (2015 May-Jun)

Bottom Line: Radiosensitive PBMC showed decrease in viability at 2 Gy, and a more significant decrease at 10 Gy for both dose rates.MDAMB- 231 cells presented viability decrease only at higher dose and dose rate.The results showed MDA-MB-231 clone expansion at low dose rate after 48-72 hours post-radiation.

View Article: PubMed Central - PubMed

Affiliation: Postdoc, Associate Professor at Universidade Federal do Amazonas (UFAM), Manaus, AM, Brazil.

ABSTRACT

Objective: In the present study, the authors investigated the in vitro behavior of radio-resistant breast adenocarcinoma (MDA-MB-231) cells line and radiosensitive peripheral blood mononuclear cells (PBMC), as a function of different radiation doses, dose rates and postirradiation time kinetics, with a view to the interest of clinical radiotherapy.

Materials and methods: The cells were irradiated with Co-60, at 2 and 10 Gy and two different exposure rates, 339.56 cGy.min(-1) and the other corresponding to one fourth of the standard dose rates, present over a 10-year period of cobalt therapy. Post-irradiation sampling was performed at pre-established kinetics of 24, 48 and 72 hours. The optical density response in viability assay was evaluated and a morphological analysis was performed.

Results: Radiosensitive PBMC showed decrease in viability at 2 Gy, and a more significant decrease at 10 Gy for both dose rates. MDAMB- 231 cells presented viability decrease only at higher dose and dose rate. The results showed MDA-MB-231 clone expansion at low dose rate after 48-72 hours post-radiation.

Conclusion: Low dose rate shows a possible potential clinical impact involving decrease in management of radio-resistant and radiosensitive tumor cell lines in cobalt therapy for breast cancer.

No MeSH data available.


Related in: MedlinePlus

Survival curve determined by the MTT test, before and after invitro exposure of MDA-MB-231 cell culture at the dose of 2 Gy. Theblack bar represents the control of non-irradiated cells, and the light graybar represents the culture irradiated with 2 Gy, with the dose rate of X =339.56 cGy/min and X/4. The bars express the mean of triplicates and thestandard deviation for MDA-MB-231 cell cultures, irradiated at the dose of 2 Gyand also for the respective control (non-irradiated). The signal * representsstatistically significant difference in relation to the bars without *(p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4492568&req=5

f04: Survival curve determined by the MTT test, before and after invitro exposure of MDA-MB-231 cell culture at the dose of 2 Gy. Theblack bar represents the control of non-irradiated cells, and the light graybar represents the culture irradiated with 2 Gy, with the dose rate of X =339.56 cGy/min and X/4. The bars express the mean of triplicates and thestandard deviation for MDA-MB-231 cell cultures, irradiated at the dose of 2 Gyand also for the respective control (non-irradiated). The signal * representsstatistically significant difference in relation to the bars without *(p < 0.05).

Mentions: Dose of 2 Gy at standard rates and at one fourth of the standardrate - Evaluation of cell viability by MTT testing of invitro MDA-MB-231 cells suspensions irradiated with 2 Gy at the 339.56cGy.min-1 dose rate and at one fourth of the standard rate, as shown onFigure 4. The control experimentdemonstrated the capability of the MDA-MB-231 cells to fill the T-25 vial andmaintain the clonogenicity beyond the 48h post confluence without exchanging theculture medium, as one observes on the control viability curve (Figure 4). The control experiment also demonstrated that after 72hours the cell concentration is high and cell density leads to a high consumption ofnutrients from the supplemented medium, making it acid on account of the excretedwaste products over the 70-120-hour period, under the conditions of no mediumexchange. As a low radiation dose is considered, the observed results in this assaywere opposed to the observations made for the PBMCs in culture, under the sameexposure conditions and correlated doses. Besides not pointing towards decrease incellular viability after irradiation with 2 Gy, the data actually demonstrated anenhancement of such viability, suggesting a clonal expansion at such dose,particularly after 48 hours in culture. The same observations were made for the 2 Gydose at one fourth of the dose rate, also suggesting a radioresistance when the dosewas reduced (Figure 4). It is possible toobserve that the dose rate reduction did not significantly impact the survival after24 hours, but became impacted the viability at 48 and 72 hours, with the lower rateleading to an increase in cell survival along time.


Enhancement of viability of radiosensitive (PBMC) and resistant (MDA-MB-231) clones in low-dose-rate cobalt-60 radiation therapy.

Falcão PL, Motta BM, de Lima FC, Lima CV, Campos TP - Radiol Bras (2015 May-Jun)

Survival curve determined by the MTT test, before and after invitro exposure of MDA-MB-231 cell culture at the dose of 2 Gy. Theblack bar represents the control of non-irradiated cells, and the light graybar represents the culture irradiated with 2 Gy, with the dose rate of X =339.56 cGy/min and X/4. The bars express the mean of triplicates and thestandard deviation for MDA-MB-231 cell cultures, irradiated at the dose of 2 Gyand also for the respective control (non-irradiated). The signal * representsstatistically significant difference in relation to the bars without *(p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492568&req=5

f04: Survival curve determined by the MTT test, before and after invitro exposure of MDA-MB-231 cell culture at the dose of 2 Gy. Theblack bar represents the control of non-irradiated cells, and the light graybar represents the culture irradiated with 2 Gy, with the dose rate of X =339.56 cGy/min and X/4. The bars express the mean of triplicates and thestandard deviation for MDA-MB-231 cell cultures, irradiated at the dose of 2 Gyand also for the respective control (non-irradiated). The signal * representsstatistically significant difference in relation to the bars without *(p < 0.05).
Mentions: Dose of 2 Gy at standard rates and at one fourth of the standardrate - Evaluation of cell viability by MTT testing of invitro MDA-MB-231 cells suspensions irradiated with 2 Gy at the 339.56cGy.min-1 dose rate and at one fourth of the standard rate, as shown onFigure 4. The control experimentdemonstrated the capability of the MDA-MB-231 cells to fill the T-25 vial andmaintain the clonogenicity beyond the 48h post confluence without exchanging theculture medium, as one observes on the control viability curve (Figure 4). The control experiment also demonstrated that after 72hours the cell concentration is high and cell density leads to a high consumption ofnutrients from the supplemented medium, making it acid on account of the excretedwaste products over the 70-120-hour period, under the conditions of no mediumexchange. As a low radiation dose is considered, the observed results in this assaywere opposed to the observations made for the PBMCs in culture, under the sameexposure conditions and correlated doses. Besides not pointing towards decrease incellular viability after irradiation with 2 Gy, the data actually demonstrated anenhancement of such viability, suggesting a clonal expansion at such dose,particularly after 48 hours in culture. The same observations were made for the 2 Gydose at one fourth of the dose rate, also suggesting a radioresistance when the dosewas reduced (Figure 4). It is possible toobserve that the dose rate reduction did not significantly impact the survival after24 hours, but became impacted the viability at 48 and 72 hours, with the lower rateleading to an increase in cell survival along time.

Bottom Line: Radiosensitive PBMC showed decrease in viability at 2 Gy, and a more significant decrease at 10 Gy for both dose rates.MDAMB- 231 cells presented viability decrease only at higher dose and dose rate.The results showed MDA-MB-231 clone expansion at low dose rate after 48-72 hours post-radiation.

View Article: PubMed Central - PubMed

Affiliation: Postdoc, Associate Professor at Universidade Federal do Amazonas (UFAM), Manaus, AM, Brazil.

ABSTRACT

Objective: In the present study, the authors investigated the in vitro behavior of radio-resistant breast adenocarcinoma (MDA-MB-231) cells line and radiosensitive peripheral blood mononuclear cells (PBMC), as a function of different radiation doses, dose rates and postirradiation time kinetics, with a view to the interest of clinical radiotherapy.

Materials and methods: The cells were irradiated with Co-60, at 2 and 10 Gy and two different exposure rates, 339.56 cGy.min(-1) and the other corresponding to one fourth of the standard dose rates, present over a 10-year period of cobalt therapy. Post-irradiation sampling was performed at pre-established kinetics of 24, 48 and 72 hours. The optical density response in viability assay was evaluated and a morphological analysis was performed.

Results: Radiosensitive PBMC showed decrease in viability at 2 Gy, and a more significant decrease at 10 Gy for both dose rates. MDAMB- 231 cells presented viability decrease only at higher dose and dose rate. The results showed MDA-MB-231 clone expansion at low dose rate after 48-72 hours post-radiation.

Conclusion: Low dose rate shows a possible potential clinical impact involving decrease in management of radio-resistant and radiosensitive tumor cell lines in cobalt therapy for breast cancer.

No MeSH data available.


Related in: MedlinePlus