Page 8 - PR 2014 2016 04 Biotechnology

94 Biotechnology | Progress Report

developed studies focusing some interlinked tential. A third aspect (therapeutic approach)
aspects. The objective of the cytogenetic con- consists in evaluating the cytogenetic effects
sists of a comparative study of the effects of of radiopharmaceuticals used in nuclear med-
different radiation types and radionuclides of icine, e.g. 131 I, administered to patients with
medical interest ( Sm, Lu, I, F, Ga), in differentiated thyroid carcinoma (DTC), with
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131
68
153
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human and rodent cells, by cytogenetic and or without the use of recombinant human
biochemical techniques. The second aspect thyrotropin (ThyrogenR or rhTSH) (project
of our study consists in the establishment approved by FAPESP), was carried out in col-
of dose-response curves for different types laboration with the Nuclear Medicine Center
of radiation (γ, β and neutron) for biological of FMUSP. A study also using human thyroid
dosimetry (dosimetric aspect) directed to the cancer cells (WRO) was published for compar-
quantitative estimate of absorbed dose, ac- ing the radiosensitivity between target cells
cording to the criteria adopted by IAEA (2001). of radioiodine (thyroid cells) and peripheral
The calibration curves for the γ radiation of lymphocytes of patients with DTC. Included
60 Co and Cs, for the β radiation of Sr and for in this research area is also a collaboration
137
90
fission neutrons produced in the Reactor R1 of study joining researchers from the Centers
IPEN-CNEN/SP have already been established of Biotechnology and Radio pharmacy and
by assessment of chromosome aberrations, the Biosintesis Laboratory for pre-clinical
micronucleus and comet assays An improved trials of radiopharmaceuticals produced at
in vitro micronucleus assay for biological the Radiopharmacy Center (IPEN-CNEN/SP).
dosimetry was introduced in our laboratory This work was supported by an institutional
utilizing fluorescent staining technique on grant, and the final results were published.
human tumor cells (MCF-7) treated with a After these achievements, our Laboratory is
nitric oxide inhibitor and irradiated ( Co). This currently working on a flow-cytometry based
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showed that nitric oxide inhibition could be a methodology to micronucleus scoring, with
radio sensitizing approach in tumor therapy, some relevant results (Fig. 2). This improve-
increasing radio induced genotoxic damage ment will reduce dramatically the duration
and reducing cell viability and clonogenic po- of genotoxicity studies.

Figure 2. a-d) Scatter plots of MN events from CHO-K1
cells irradiated up to 16 Gy using a Co source. e) Plot of
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results. Positive control (MTMC, mitomycin C) and dos-
es from 4 to 16 Gy caused MN induction on cells.

Instituto de Pesquisas Energéticas e Nucleares