This document summarizes research investigating the role of SREBP-2 in breast cancer metastasis to bone. SREBP-2 was found to positively regulate osteoclast formation and bone resorption in vitro. It also regulates the expression of NFATc1 during osteoclastogenesis through the RANKL/CREB signaling pathway. As SREBP-2 promotes factors involved in bone destruction and breast cancer spread, inhibiting SREBP-2 may be a potential therapeutic approach for breast cancer patients with bone metastases.

1. LAURA AGUDELO VERGARA
3 Semestre|Facultad de Medicina|Universidad Pontificia Bolivariana

2. INTRODUCTIONBREASTCANCER
Is a malignant proliferation of
epithelial cells lining the ducts
or lobules of the breast.
Is principally a disease of older
women. Seventy-five percent
of all breast cancers occur in
women aged >50 years.
Develops as a series of
molecular changes in the
epithelial cells that lead to
ever more malignant
behavior.
It is also a hormone-
dependent disease.
SREBP-2
Activate expression of the LDL
receptor.
Is a protein that regulate the
synthesis and cellular uptake of two
major building blocks of cell
membranes: cholesterol and fatty
acids.
Activate expression of genes such
as HMGCR, HMGCS, MVK, FASN
and ACC.
Has an unanticipated function in
survival and limb patterning during
development.

3. INTRODUCTION
SREBP-2
BREASTCANCER
Bone is one of the most common sites of breast cancer
metastasis. The SREBP-2 play in osteoclast formation a
function, and in breast cancer metastasis.
SREBP-2 was also found to be highly expressed in breast
cancer tissues and correlated with a poor prognosis.
SREBP- 2 inhibition is a potential therapeutic approach for
breast cancer patients with osteolytic bone lesions.
SREBP-2 plays a critical role in regulating
osteoclastogenesis and contributes to breast cancer-
induced osteolysis.

4. Demonstrate the effects of SREBP-2 on
the metastasis of breast cancer
caused in the bone.
GENERAL OBJECTIVES

5. ENSAYO IN VITRO DE OSTEOCLASTOGÉNESIS
Monocitos de la médula ósea / macrófagos (BMM)
RANKL
PBS / M-CSF
MATERIALES
Estreptomicina / Penicilina
CULTIVO CELULAR
Ratones C57BL / 6 machos de
6 semanas
Monocitos de la médula ósea
/ macrófagos (BMM)

6. ARN Total
Tampón de lisis RIPA (Sigma-Aldrich)
Anticuerpos
Proteína celular total
WESTERN BLOT ANÁLISIS
Geles de SDS-PAGE al 10%
Membranas de difluoruro de polivinilideno (PVDF)
EXTRACCIÓN DE ARN Y ANÁLISIS
CUANTITATIVO POR PCR
ADN complementario
Cebadores
MATERIALES

7. MÉTODOS
CULTIVO CELULAR
Determinó el desarrollo de las líneas
celulares BMM y del cancer de mama
MDA-MB-231 en medios de cultivo
adaptados.
Evalúa células animales y vegetales
aisladas que pueden vivir, multiplicarse, e
incluso presentar ciertas propiedades
diferenciales.
Técnica que producen resultados exactos
y describe los efectos de una variable
experimental en partes subconjuntos del
organismo.
Determinar la actividad de TRAP, a través
de un medio de cultivo con BMM al cual
se le agrego RANKL y M-CSF.
ENSAYO IN VITRO DE OSTEOCLASTOGÉNESIS

8. EXTRACCIÓN DE ARN Y ANÁLISIS
CUANTITATIVO POR PCR
Técnica para hacer muchas copias de
una determinada región de ADN in
vitro.
Producir suficiente ADN de la región
blanco para que pueda analizarse.
MÉTODOS
WESTERN BLOT ANÁLISIS
Técnica para evaluar la reacción
entre un antígeno y un anticuerpo.
Se hizo la marcación de SREPB-1 y
NFATc1, se evaluó su reactividad con
el anticuerpo especifico.

9. RESULTADOS
Fig. 1. SREBP-2 regula positivamente
la formación de osteoclastos y la
resorción ósea in vitro.

10. RESULTADOS
Fig. 2. SREBP-2 regula la expresión
de NFATc1 durante la
osteoclastogénesis.

11. RESULTADOS
Fig. 3. La expresión de SREBP-2 se
induce a través de la vía de
señalización dependiente de
RANKL / CREB.

12. RESULTADOS
Fig. 4. SREBP-2 es un regulador
transcripcional de la expresión
NFATc1.

13. DISCUSSION
G. Musso, R. Gambino, M. Cassader
“SREBP-2 is well study in the context of regulating cholesterol
homeostasis by transcriptionally activating its target genes.”
A.F. Chambers, A.C. Groom, I.C. MacDonald
“The contribution of the primary tumor microenvironment to
malignant progression plays a very important role.”
K. Inoue, Y. Imai
“In addition, the SREBP inhibitor, Fatostatin, has been reported to
prevent RANKL-induced bone loss by suppressing osteoclast
differentiation.”
A.A. Gholkar, K. Cheung, K.J. Williams, Y.C. Lo, S.A.
Hamideh, C. Nnebe, C. Khuu
“Furthermore, SREBP inhibition was recently found to exert multiple
antitumor effects in various tumors.”

14. CONCLUSSION
The SREBP-2 can be considered as a therapeutic and
preventive method in the future to avoid the metastasis of
breast cancer in the bone
According to the results obtained from the investigation, it
can be shown that the main hypothesis is not correct
because it was visualized that the effect of SREBP-2 is
contrary to what was expected.

15. CONCEPTUAL MAP