Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes
The main aim of this work was to determine subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in the primary monolayer culture of thyrocytes obtained from undamaged follicles. In the thyroid follicles S6K1, S6K2 have been detected predominantly in the cytoplasm of the cel...
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Khoruzhenko, A.I. Cherednyk, O.V. Filonenko, V.V. 2019-06-20T16:16:34Z 2019-06-20T16:16:34Z 2008 Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes / A.I. Khoruzhenko, O.V. Cherednyk, V.V. Filonenko // Біополімери і клітина. — 2008. — Т. 24, № 1. — С. 35-40. — Бібліогр.: 36 назв. — англ. 0233-7657 http://dx.doi.org/10.7124/bc.00078E https://nasplib.isofts.kiev.ua/handle/123456789/157661 591.87:611.44:577.25 The main aim of this work was to determine subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in the primary monolayer culture of thyrocytes obtained from undamaged follicles. In the thyroid follicles S6K1, S6K2 have been detected predominantly in the cytoplasm of the cells, however, in the monolayer culture of thyrocytes in the course of follicles outspreading S6K1 and S6K2 have been observed in nuclei as well. Such redistribution of S6K was not directly related to the appearance of proliferating Ki-67 positive cells. At the same time there was a correlation between the appearance of S6K1, S6K2 positive nuclei in monolayer thyrocyte culture and decrease in thyroglobulin content in cultured cells. Thus, the obtained results indicated that the down regulation of thyrocyte functional activity caused by the loss of follicle organization was accompanied by subcellular redistribution of S6K1 and S6K2. мунохімічно визначено субклітинну локалізацію S6K1 і S6K2 у тканині та моношаровій культурі щитовидної залози щурів. Встановлено, що в тканині щитовидної залози S6K1 і S6K2 локалізуються переважно в цитоплазмі клітин. При розпластуванні фолікулів з’являлася позитивна реакція в ядрах тиреоцитів. Такий перерозподіл не пов’язаний прямо з появою проліферуючих Ki-67 позитивних клітин. У той же час відмічено кореляцію між появою S6K1, S6K2 позитивних ядер і зменшенням вмісту тиреоглобулину у культивованх клітинах. Таким чином, отримані результати свідчать про те, що зниження функціональної активності тиреоцитів внаслідок втрати фолікулярної організації супроводжується зміною субклітинної локалізації S6K1 і S6K2. Иммунохимически определена субклеточная локализация S6K1, S6K2 в ткани и монослойной культуре клеток щитовидной железы крыс. В исходной ткани S6K1 и S6K2 локализовались преимущественно в цитоплазме. При распластывании фолликулов положительная реакция появлялась и в ядрах тиреоцитов. Такое перераспределение напрямую не связано с появлением пролиферирующих Ki-67 положительных клеток. При этом отмечалась корреляция между появлением S6K1, S6K2 положительных ядер и снижением содержания тиреоглобулина в культивируемых клетках. Полученные нами результаты свидетельствуют о том, что снижение функциональной активности тиреоцитов вследствие потери фолликулярной организации сопровождается изменением субклеточной локализации S6K1 и S6K2. en Інститут молекулярної біології і генетики НАН України Біополімери і клітина Клітинна біологія Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes Субклеточная локализация S6K1 и S6K2 форм рибосомной протеинкиназы S6 в первичной монослойной культуре тиреоцитов крыс Субклітинна локалізація S6K1 і S6K2 форм рибосомної протеїнкінази S6 у первинній моношаровій культурі тиреоцитів щурів Article published earlier |
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| title |
Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes |
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Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes Khoruzhenko, A.I. Cherednyk, O.V. Filonenko, V.V. Клітинна біологія |
| title_short |
Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes |
| title_full |
Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes |
| title_fullStr |
Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes |
| title_full_unstemmed |
Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes |
| title_sort |
subcellular localization of s6k1 and s6k2 forms of ribosomal protein s6 kinase in primary monolayer culture of rat thyrocytes |
| author |
Khoruzhenko, A.I. Cherednyk, O.V. Filonenko, V.V. |
| author_facet |
Khoruzhenko, A.I. Cherednyk, O.V. Filonenko, V.V. |
| topic |
Клітинна біологія |
| topic_facet |
Клітинна біологія |
| publishDate |
2008 |
| language |
English |
| container_title |
Біополімери і клітина |
| publisher |
Інститут молекулярної біології і генетики НАН України |
| format |
Article |
| title_alt |
Субклеточная локализация S6K1 и S6K2 форм рибосомной протеинкиназы S6 в первичной монослойной культуре тиреоцитов крыс Субклітинна локалізація S6K1 і S6K2 форм рибосомної протеїнкінази S6 у первинній моношаровій культурі тиреоцитів щурів |
| description |
The main aim of this work was to determine subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in the primary monolayer culture of thyrocytes obtained from undamaged follicles. In the thyroid follicles S6K1, S6K2 have been detected predominantly in the cytoplasm of the cells, however, in the monolayer culture of thyrocytes in the course of follicles outspreading S6K1 and S6K2 have been observed in nuclei as well. Such redistribution of S6K was not directly related to the appearance of proliferating Ki-67 positive cells. At the same time there was a correlation between the appearance of S6K1, S6K2 positive nuclei in monolayer thyrocyte culture and decrease in thyroglobulin content in cultured cells. Thus, the obtained results indicated that the down regulation of thyrocyte functional activity caused by the loss of follicle organization was accompanied by subcellular redistribution of S6K1 and S6K2.
мунохімічно визначено субклітинну локалізацію S6K1 і S6K2 у тканині та моношаровій культурі щитовидної залози щурів. Встановлено, що в тканині щитовидної залози S6K1 і S6K2 локалізуються переважно в цитоплазмі клітин. При розпластуванні фолікулів з’являлася позитивна реакція в ядрах тиреоцитів. Такий перерозподіл не пов’язаний прямо з появою проліферуючих Ki-67 позитивних клітин. У той же час відмічено кореляцію між появою S6K1, S6K2 позитивних ядер і зменшенням вмісту тиреоглобулину у культивованх клітинах. Таким чином, отримані результати свідчать про те, що зниження функціональної активності тиреоцитів внаслідок втрати фолікулярної організації супроводжується зміною субклітинної локалізації S6K1 і S6K2.
Иммунохимически определена субклеточная локализация S6K1, S6K2 в ткани и монослойной культуре клеток щитовидной железы крыс. В исходной ткани S6K1 и S6K2 локализовались преимущественно в цитоплазме. При распластывании фолликулов положительная реакция появлялась и в ядрах тиреоцитов. Такое перераспределение напрямую не связано с появлением пролиферирующих Ki-67 положительных клеток. При этом отмечалась корреляция между появлением S6K1, S6K2 положительных ядер и снижением содержания тиреоглобулина в культивируемых клетках. Полученные нами результаты свидетельствуют о том, что снижение функциональной активности тиреоцитов вследствие потери фолликулярной организации сопровождается изменением субклеточной локализации S6K1 и S6K2.
|
| issn |
0233-7657 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/157661 |
| citation_txt |
Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in primary monolayer culture of rat thyrocytes / A.I. Khoruzhenko, O.V. Cherednyk, V.V. Filonenko // Біополімери і клітина. — 2008. — Т. 24, № 1. — С. 35-40. — Бібліогр.: 36 назв. — англ. |
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2025-11-25T21:04:14Z |
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| fulltext |
Subcellular localization of S6K1 and S6K2 forms of
ribosomal protein S6 kinase in primary monolayer
culture of rat thyrocytes
A. I. Khoruzhenko, O. V. Cherednyk, V. V. Filonenko
Institute of Molecular Biology and Genetics of National Academy of Sciences of Ukraine
150, Zabolotny Str., Kyiv, 03680, Ukraine
filonenko@imbg.org.ua
The main aim of this work was to determine subcellular localization of S6K1 and S6K2 forms of ribosomal
protein S6 kinase in the primary monolayer culture of thyrocytes obtained from undamaged follicles. In the
thyroid follicles S6K1, S6K2 have been detected predominantly in the cytoplasm of the cells, however, in the
monolayer culture of thyrocytes in the course of follicles outspreading S6K1 and S6K2 have been observed
in nuclei as well. Such redistribution of S6K was not directly related to the appearance of proliferating
Ki-67 positive cells. At the same time there was a correlation between the appearance of S6K1, S6K2
positive nuclei in monolayer thyrocyte culture and decrease in thyroglobulin content in cultured cells.
Thus, the obtained results indicated that the down regulation of thyrocyte functional activity caused by the
loss of follicle organization was accompanied by subcellular redistribution of S6K1 and S6K2.
Key words: ribosomal protein S6 kinase, thyrocytes, primary culture.
Introduction. The principal regulators of thyroid
growth and hormone synthesis are thyroid stimulating
hormone (TSH) and insulin and dysfunction of thyroid
is often connected to abnormalities of signal
transduction into the cell [1, 2]. Recent investigations
have shown that both of them exhibit their effect on
target cells through PI3K signal transduction pathway
[3–5]. The ribosomal protein S6 kinase (S6K) is an
important member of this pathway. The S6K along
with protein kinase C and B belong to the AGC family
of Ser/Thr protein kinases. There are two forms of S6
kinase, S6K1 and S6K2, each one of them has
cytoplasmic and nuclear variants derived from
alternative splicing at N-terminus [6]. Initially
ribosomal protein S6 (rpS6) was considered to be the
only substrate for S6K. Phosphorylation, catalyzed by
S6K, leads to activation of rpS6, which consequently
takes part in regulation of cell size, protein synthesis,
and glucose homeostasis. But recently several new
substrates including eukaryotic translation initiation
factor 4B (eIF4B), cAMP-responsive element
modulator t (CREMt), 80 kDa subunit of the nuclear
Capbinding complex (CBP80), and S6K1
Aly/REF-like target (SKAR) have been identified
[7–9]. The inhibitory effect of S6K was demonstrated
for insulin receptor substrates IRS1, IRS2, BAD, and
eukaryotic elongation factor 2 kinases (eEF2K) [10].
Currently, there are a lot of evidences suggesting
the involvement of S6K in the regulation of cell cycle
[11–13]. These data indicate the possible link between
subcellular localization of S6K and its role in the
processes of cell proliferation and maintenance of the
tissue functional activity.
35
ISSN 0233-7657. Biopolymers and cell. 2008. Vol. 24. N 1.
Ó A. I. KHORUZHENKO, O. V. CHEREDNYK, V. V. FILONENKO, 2008
Previous investigations of our laboratory on breast
cancer model have shown that subcellular localization
of S6K is not static. It was demonstrated that S6K2
appeared in the nuclei of malignant cells as opposed to
normal breast tissue [14].
It is well established that endocrine activity of the
thyroid gland depends on its follicular organization [15,
16]. The disturbances in follicular structure at various
levels affect synthesis of thyroid hormones. Such
consequences have been observed upon changes at
tissue (follicle damage, hypo- and hyperplasia) [17]
cellular, and molecular (derangements of desmosome
distribution, change of quantitative and qualitative
composition of extracellular matrix, etc.) [18] levels.
Earlier it was shown that the loss of follicular structure
in vitro leads to decrease in functioning of thyrocytes
[19]. Currently, there are several culture models
available for investigation of thyrocytes. Thyrocytes in
primary culture can be studied as monolayer [20], as
reorganized follicles in suspension [21], embedded in
collagen gel [22], as floating aggregates of follicles
[23], and as monolayer on filters set between two
chambers [24]. Functional activity of cultured
thyrocytes could be assayed using such markers as
iodine uptake and transport [25], thyroglobulin
synthesis [26], thyroperoxidase and deiodinase
activities [27], T3 and T4 level [28]. In this study we
have employed an approach, which allows monitoring
the changes in thyrocytes in the course of their
rearrangements from undamaged follicles to uniform
monolayer. Primary monolayer culture utilized in this
study was initiated from undamaged follicles that were
obtained from initial rat thyroid tissue. Our previous
studies, performed on the primary monolayer culture of
thyrocytes, demonstrated multiple changes including
decrease in thyroglobulin content, activation of cell
migration, and proliferation [23]. The main goal of the
present work was to study subcellular localization of
S6K in rat thyrocytes in the course of follicles
rearrangement under conditions of monolayer culture.
Materials and Methods. Reagents. RPMI-1640
medium, glutamine, amphotericin B, penicillin-
streptomycin mixture, dispase, trypsin inhibitor,
monoclonal anti-Pan cytokeratin (Pck) mouse
antibodies were obtained from «Sigma» (USA).
Collagenase CLS 2 was purchased from «Worthington
Biochemical Corporation», USA. Foetal calf serum
(FCS) was supplied by «Helena Bioscience» (USA).
Monoclonal anti-thyroglobulin and anti-Ki-67
antibodies were obtained from «Dakopatts»
(Denmark). Monoclonal antibodies to S6K1 and S6K2
were obtained in our laboratory using the method,
described in [14, 29].
Cell culture. For each experiment samples of sterile
thyroid glands excised from three Wistar rat males were
placed into Petri dish with RPMI-1640 medium,
supplemented with 5-fold concentration of penicil-
lin/streptomycin and were freed from the fibrous
capsule. The thyroid tissue was cut into small fragments
(1.5–2.0 mm), rinsed in phosphate buffered saline, pH
7.2 (PBS), and incubated with a mixture of collagenase
(0.5 mg/ml), dispase (1 mg/ml), trypsin inhibitor
(1 mg/ml) in PBS for 20 min at 37 °C.
The enzyme mixture was changed once, and the
fragments of thyroid tissue were incubated for another
30–40 min at 37 °C with agitation every 10 min. After
that, 5 ml of growth medium (RPMI-1640 with 17 %
FCS, 4 mM glutamine, 50 units/ml penicillin, 50 mg/ml
streptomycin, 1 mg/ml amphotericin B) were added to
the tissue sample. Disaggregated by pipetting material
was then filtered through nylon mesh (dpore = 180 mm)
and collected on nylon mesh (dpore = 40 mm). The
isolated follicles have been washed with 10 ml of
growth medium and collected by centrifugation (8 min,
1500 rpm). The pellet was then resuspended in growth
medium and the follicles were transferred into 60 mm
dishes, coated with 1 % gelatine layer. Cultivation was
carried out at 37 °C under humidified 7 % CO2-air.
Immunocytochemical and immunohistochemical
analysis. S6K1/S6K2 localization, thyroglobulin,
Ki-67 antigen, epithelial antigens (Pck) were
determined by indirect immunoperoxidase method
using paraffin sections of initial rat thyroid tissue and
primary cell cultures. Representative sections obtained
from paraffin blocks were deparaffinized and
rehydrated. Endogenous peroxidase was quenched
with 1 % H2O2 in PBS for 1 hour. After blocking of
non-specific staining with 10 % FCS in PBS, sections
were incubated for 2 hours at 37 °C with primary
antibodies, and thereafter they were incubated with
peroxidase-conjugated secondary antibodies for 1 hour
at 37 °C. The reaction was developed with
36
KHORUZHENKO A. I., CHEREDNYK O. V., FILONENKO V. V.
3,3'-diaminobenzidine solution. Thyrocyte cultures
were fixed with cooled methanol for 20 min at –20 °C.
After fixation, the cells were permeabilized with 0.2 %
Triton X-100 in PBS for 15 min. The following
dilutions of antibodies were utilized: S6K1, 1:50;
S6K2, 1:200; Tg, 1:100; Ki-67, 1:50; Pck, 1:100. All
experiments were repeated three times. All microscopy
studies were performed using Leica DM1000 light
microscope (Germany).
Results and Discussion. Detection of
thyroglobulin content in cultured thyrocyte. The
approach, applied in our work, allows obtaining the
suspension of undamaged follicles. The follicles were
isolated from thyroid by double-filtration of
enzymatically treated tissue. The epithelial origin of
cultured cells was confirmed using monoclonal
antibodies to epithelial antigens cytokeratins (Pck)
(unpublished data). Thyroglobulin content was used as
a marker of thyrocyte functional activity.
Thyroglobulin was detected on paraffin sections of rat
thyroid (Fig. 1, a, see plating) and in the culture of
outspreading follicles on the 3rd, (Fig. 1, b), 6th (Fig. 1,
g), and 10th (Fig. 1, j) day of cultivation using
immunoperoxidase technique. Monolayer culture
conditions employed for thyroid follicles resulted in
complete loss of their follicular organization and in
formation of uniform monolayer. Apparent difference
in thyroglobulin content between thyrocytes on the 3rd
and 10th days serves as a strong evidence of decrease of
thyrocyte functional activity.
Subcellular localization of S6K1 and S6K2 in rat
thyroid tissue and cultured thyrocytes. Subcellular
localization of S6K1 and S6K2 was examined on
paraffin sections of rat thyroid by immunohisto-
chemical technique using monoclonal antibodies to
S6K1 and S6K2. The data suggest that in rat thyroid
tissue S6K1 and S6K2 are detected predominantly in
cell cytoplasm (Fig. 1, b, c). Analysis of S6K1 and
S6K2 distribution in thyrocytes on the 3rd day of
cultivation, when attached follicles began to spread,
also showed their cytoplasmic localization (Fig. 1, e, f).
Later, on the 6th and 10th day of cultivation both forms of
S6K were detected in the cytoplasm and in the nuclei of
thyrocytes (Fig. 1, h, i and Fig. 1, k, l). It is noteworthy
that cells with S6K1, S6K2-positive nuclei appeared at
the leading edge of outspreading follicle, whereas in the
centre of follicle the nuclei were still non-stained (Fig.
2 a, b, see plating).
Detection of Ki-67 positive thyrocytes in culture.
Detection of proliferating cells was carried out in
paraffin sections of thyroid and in thyrocyte cultures on
the 3rd, 6th, and 10th days of cultivation by indirect
immunoperoxidase method using anti-Ki-67
antibodies. Ki-67 positive nuclei were not observed on
histological sections of thyroid and in thyrocytes on the
3rd day of cultivation. However, the thyrocytes positive
to Ki-67 were detected on the 6th, and especially on the
10th day of cultivation (Fig. 3, see plating). Therefore,
the data suggest that Ki-67 positive cells appeared
when S6K1 and S6K2 had translocated into nuclei.
Analysis of spatial arrangement of Ki-67 positive
thyrocytes revealed that they are evenly distributed
within outspreading follicles. Unlike S6K1, S6K2-
positive cells, the appearence of Ki-67-positive
thyrocytes was not selectively attributed to the edge of
outspreading follicles (Fig. 3).
Follicle is an essential functional unit of the thyroid
gland. It is composed of epithelium arranged as
tightly-packed spherical unit. Each follicle is lined by a
single layer of specialized thyroid epithelium, which
rests on a basement membrane and encloses a lumen
filled with thyroid colloid which is a homogeneous
proteinaceous material rich in thyroglobulin. This
structure is responsible for the synthesis of thyroid
hormones, which regulate multitude of physiological
processes, including regulation of oxygen uptake,
thermogenesis, increase of striated and heart muscles
contractility, activation of the metabolism of proteins,
lipids, carbohydrates, mineral agents etc. [30]. The
disturbance of follicle organization or merely flattening
of thyroid epithelium may lead to abnormalities in
functional properties of thyroid gland [17].
Upon selection of primary cell culture conditions it
is very important to consider strong polarization of
thyrocytes [31]. Due to specific follicular structure of
thyroid gland in vivo it was suggested that receptors to
hormones (TSH), growth factors (IGF), iodine
transporters, etc., are located on the basal membrane of
thyrocytes [32]. Since the follicular structure of thyroid
tissue is tightly connected to hormone synthesis, the
loss of this organization in monolayer culture and the
absence of TSH (conditions used in our experiments)
37
SUBCELLULAR LOCALIZATION OF S6K1 AND S6K2 FORMS OF RIBOSOMAL PROTEIN S6
KHORUZHENKO A. I., CHEREDNYK O. V., FILONENKO V. V.
lead to decrease of thyrocyte functional activity and cell
dedifferentiation. The level of thyrocytes differen-
tiation could be detected using several methods,
including measurement of iodine uptake,
iodoperoxidase and deiodinase activity, thyroglobulin,
T3 and T4 synthesis [25–28]. In the present study, the
thyroglobulin content was detected at several time
points of thyrocytes cultivation. The immunocyto-
chemical reaction of cultured thyrocytes observed
using light microscopy on the 3rd day of cultivation was
significantly stronger as opposed to on the 6th and 10th
days of cultivation. Therefore, these data suggest that
in the course of follicle transformation to uniform
monolayer the functional activity of thyrocytes was
reduced. This culture model was applied for
investigation of subcellular distribution of S6K1 and
S6K2. Obtained data suggest that in the initial tissue
both S6K1, and S6K2 are localized mainly in
cytoplasm of rat thyrocytes. Likewise human thyroid
gland [29], the immunohistochemical reaction detected
on rat tissue was feebly marked. On the 3rd day of
cultivation the positive reaction for S6K1, S6K2 was
still observed predominantly in cytoplasm. Later, on
the 6th and the 10th days of cultivation, both nucleic and
cytoplasmic fractions of cultured thyrocytes were
positive for S6K1 and S6K2. At least two kinases –
PKC and CK2 – could be partially responsible for such
distribution of S6K [6, 33].
It is very likely that the nuclear substrates of S6K
play an important role in thyroid follicles rearrange-
ments, first of all, in thyrocytes dedifferentiating
determined by the loss of thyroglobulin synthesis.
There are several nuclear substrates for S6K currently
known. These include CREMt, CBP80, SKAR, and
protein from Aly/REF family of RNA binding protein
[10].
Since the localization of Ki-67 positive cells did not
correlate with nuclear translocation of S6K1, S6K2, the
latter event probably has no connection to the activation
of cell proliferation. Furthermore, in some experiments
we noted the appearance of small quantity of S6K2
positive nuclei on the 4th and 5th days, while Ki-67
positive cells were registered mainly after 6 days of
cultivation.
Our data demonstrate that S6K nuclei positive
thyrocytes appeared at the leading edge of outspreading
thyroid follicles, whereas the nuclei of cells located in
the central area were still unstained. We can not
exclude that activation of locomotor properties of
cultured thyrocytes could be triggered by such
redistribution of S6K. According to Zhou et al. [34] the
invasive/migratory phenotype of ovarian cancer cells
activated by HGF could be blocked by specific
inhibitors of the phosphatidylinositol-3-kinase (PI3K)
cascade and particularly by inhibitor of S6K1. A
significant role of S6K1 in cell invasion is supported by
the observation that expression of constitutively active
38
SUBCELLULAR LOCALIZATION OF S6K1 AND S6K2 FORMS OF RIBOSOMAL PROTEIN S6
Fig.2 Immunocytochemical de tec tion of S6K1 (A) and S6K2 (B)
lo cal iza tion in out spread ing fol li cles on the 4th day of cul ti va tion.
S6K1 and S6K2 neg a tive nu clei are lo cated in the cen tral area
while pos i tive ones are vis i ble at the outer edge. Ob jec tive x20,
oc u lar x10.
Fig.3 De tec tion of pro lif er at ing thyrocytes on 10th day of cul ti va -
tion. Ar rows show Ki-67 pos i tive cells in the cen tre of out spread -
ing fol li cles. Ob jec tive x40, oc u lar x10.
forms of S6K1 is sufficient to induce invasive and
migratory phenotypes in ovarian cancer cells [34, 35].
Subcellular localization of S6K1 and S6K2 was
earlier studied in our laboratory using smears of normal
and cancer breast tissue. The data obtained suggested
that the level of S6K1 and S6K2 expression in breast
tumours is much higher, compared to that of the normal
tissue. In addition the intensive cytoplasmic and
nuclear staining of S6K2 was demonstrated in tumor
samples but not in normal tissue. Collectively these
data indicate that S6K is involved in the process of cell
transformation accompanied by cell dedifferentiation
and invasion [36].
In conclusion, our investigation suggests that
decrease in thyrocyte functional activity, triggered by
the loss of follicle organization in vitro, is accompanied
by subcellular nuclear-cytoplasmic redistribution of
ribosomal protein S6 kinases S6K1 and S6K2.
Additional studies are necessary to understand fully the
underlying mechanism of this phenomenon.
À. È. Õî ðó æåí êî, Î. Â. ×å ðåä íèê, Â. Â. Ôè ëî íåí êî
Ñóá êëå òî÷ íàÿ ëî êà ëè çà öèÿ S6K1 è S6K2 ôîðì ðè áî ñîì íîé
ïðî òå èí êè íà çû S6 â ïåð âè÷ íîé ìî íîñ ëîé íîé êóëü òó ðå
òè ðå î öè òîâ êðûñ
Ðå çþ ìå
Èììó íî õè ìè ÷åñêè îïðå äå ëåíà ñóá êëå òî÷íàÿ ëî êà ëè çà öèÿ
S6K1, S6K2 â òêà íè è ìî íîñ ëîé íîé êóëü òó ðå êëå òîê ùè òî âèä -
íîé æå ëå çû êðûñ. Â èñ õîä íîé òêà íè S6K1 è S6K2 ëî êà ëè çî âà -
ëèñü ïðå è ìó ùåñ òâåí íî â öè òîï ëàç ìå. Ïðè ðàñ ïëàñ òû âà íèè
ôîë ëè êó ëîâ ïî ëî æè òåëü íàÿ ðå àê öèÿ ïî ÿâ ëÿ ëàñü è â ÿä ðàõ òè -
ðåî öè òîâ. Òà êîå ïå ðåðàñ ïðå äå ëå íèå íà ïðÿ ìóþ íå ñâÿ çà íî ñ ïî -
ÿâ ëå íè åì ïðî ëè ôå ðè ðó þ ùèõ Ki-67 ïî ëî æè òåëü íûõ êëå òîê.
Ïðè ýòîì îò ìå ÷à ëàñü êîð ðå ëÿ öèÿ ìåæ äó ïî ÿâ ëå íè åì S6K1,
S6K2 ïî ëî æè òåëü íûõ ÿäåð è ñíè æå íè åì ñî äåð æà íèÿ òè -
ðåîãëî áó ëè íà â êóëü òè âè ðó å ìûõ êëåò êàõ. Ïî ëó ÷åí íûå íàìè ðå -
çóëü òà òû ñâè äå ò åëüñòâó þò î òîì, ÷òî ñíè æå íèå
ôóíê öè î íàëü íîé àê òèâ íîñ òè òè ðå î öè òîâ âñëå äñòâèå ïî òå ðè
ôîë ëè êó ëÿð íîé îðãà íè çà öèè ñî ïðî âîæ äà åò ñÿ èç ìå íå íè åì ñóá -
êëå òî÷ íîé ëî êà ëè çà öèè S6K1 è S6K2.
Êëþ ÷å âûå ñëî âà: ðè áî ñîì íàÿ ïðî òå èí êè íà çà S6, òè ðå î öè -
òû, ïåð âè÷ íàÿ êóëü òó ðà.
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