Oncogenes y Antioncogenes Dr. Daniel R. CIOCCA IMBECU ...

Oncogenes y Antioncogenes
Dr. Daniel R. CIOCCA
IMBECU (Unidad Ejecutora del CONICET)
Fund. Argentina Investigación Cáncer
MENDOZA

Oncogénesis Mamaria
INICIADORES - Alteración genética
Mutación hereditaria (BRCA1, etc..) o Adquirida
(radiaciones, metabolismo endógeno, químicos, fármacos,
virus, hormonas)
oncogenes-antioncogenes
PROMOTORES – Expanden alt. genética
Hormonas
FACILITADORES – Disminuyen defensas
Inmunodepresores (stress, fármacos, enfermedades,
hormonas)

Oncogenes
Proto-oncogenes: . Multiplicación celular
. Diferenciación
. Muerte/sobrevida
Alteración dominante
. Mutaciones puntuales
. Amplificación (múltiples copias de ADN)
. Translocación (rearreglos estructurales)
Oncogenes

Daños endógenos Daños exógenos
Durante la replicación del ADN:
incorporación de U
Desaminación de A, G o C
Hidrólisis de uniones N-glucosílicas:
despurinación/despirimidación
Oxidación de bases: ERO
Radiaciones: ionizante y UV
Carcinógenos químicos:
benzopireno,
hidrocarburos aromáticos policíclicos
Drogas antineoplásicas

Ph cromosome, CML
t(9;22)(q34;q11)
Abl codifica tirosina quinasa
que cuando se fusiona con
Bcr es constitutivamente activa
Cromosomas involucrados Bandas afectadas por los puntos de ruptura

Genes Supresores Tumorales (Antioncogenes):
. Multiplicación celular
. Reparación daños al ADN
. Muerte/sobrevida
Mutaciones recesivas
Metilaciones
Pérdida del Antioncogen
Cascada de Defectos del Genoma/Proteoma

P
HPV-16
E7
Rb-Mediated Regulation of Cyclin E Transcription
Rb
HDAC-1
P
Cyclin
CDK
Pol II
Pol II
HDAC-1
Rb
E2F
E2F
T-Ag
Cyclin E
CDK 2
HDAC-1
Rb
T-Ag

Rayos X
Radicales libres
Agentes alquilantes
Reacciones espontáneas
U G
G
Uracilo
Sitio abásico
8-oxoguanina
Rupturas de simple cadena
T
Luz UV
Hidrocarburos
aromáticos
policíclicos
T
T
(6-4)PP
Aductos
DCP
C
Rayos X
Antineoplásicos
(Cisplatino)
G G
Uniones cruzadas
Rupturas de doble cadena
Errores de
replicación
A
G
C
T
Bases mal apareadas
Inserciones
Deleciones
BER NER HR, EJ MMR
Síndromes con reparación
del ADN defectuosa
HSP in DNA repair
Nadin & Ciocca
In press
Síndrome Mecanismo gen/proteína Inestabilidad Relación
afectado afectada genómica con cáncer
Xeroderma NER (+/- TCR) XPC/XPC Mutaciones de piel
Pigmentosum XPA/XPA puntuales inducido por UV
(XP) XPD/XPD o por exposición a
XPG/XPG agentes químicos
XPF/XPF
HNPCC MMR hMLH1/hMSH2 Mutaciones Cáncer colorectal
hMSH6/hPMS1/hPMS2 puntuales
BRCA1/BRCA2 HR BRCA1/BRCA2 Aberraciones Cáncer de mama
cromosómicas (ovario)
Ataxia Telangiectasia DSB repair ATM Aberraciones Linfomas
cromosómicas

Genomic analysis of a spontaneous model of breast cancer metastasis
to bone revels a role for the extracellular matrix
Eckhardt BL et al (Robin Anderson). Peter MacCallum Cancer Center, Australia

Primary tumour expression of the cysteine cathepsin inhibitor Stefin A inhibits
distant metastasis in breast cancer
BS Parker, DR Ciocca, et al
Journal of Pathology 214:337-346 (2008).
Cysteine cathepsin inhibitor Stefin A as a gene differentially expressed in primary and
metastatic mammary tumours.
In primary tumours, Stefin A expression correlated inversely with metastatic potential
in 4T1-derived lines and was not detected in tumour cells in culture, indicating induction
only within the tumour microenvironment. Enforced expression of Stefin A in the highly
metastatic 4T1.2 cell line significantly reduced spontaneous bone metastasis following
orthotopic injection into the mammary gland.
There have been no reports of Stefin A expression in metastases in vivo and the relative
expression of Stefin A and the cysteine cathepsins, including their cellular localization,
has not been studied in bone metastasis. In this report, we document the expression and
localization of Stefin A in mouse and human breast tumours and provide functional
evidence for its potential role as a prognostic/therapeutic in advanced breast cancer.

RNA isolated from primary tumours was
reverse-transcribed and real-time RT–PCR was
used to detect Stefin A1, A2 and A3 expression
relative to GAPDH. RTA, relative transcript
abundance. ∗∗p < 0.05 (4T1 to 4T1.2/ 4T1.35)
Stefin A reduces spontaneous metastasis to bone. Stefin A1-containing or
BV-retroviral vectors were used to infect 4T1.2neo1 tumour cells.
A.- Real-time RT–PCR and western blot detection of Stefin A1 RNA and protein expression (flag tag
protein) in pooled and single cell clones.
B.- RT–QPCR detection of tumour burden in spine (using neomycin-tagged 4T1.2 cells) in mice
injected with 4T1.2 BV or 4T1.2 StfA1. RTB is the relative tumour burden (left) and plasma
calcium serum concentration (mg/dl) in tumour-bearing and non-tumour-bearing mice (right).

PEFF sections of reduction mammoplasty tissue, primary
breast tumours and metastases in lung and bone were stained
with mouse anti-human Stefin A or 1B5 hybridoma
supernatant control and visualized with DAB.
Kaplan–Meier analysis comparing disease-free
survival (DFS) (B)
and death due to cancer (DDC) (C)

Co-expression of Stefin A and cathepsin B in lung and bone metastases. Stefin A fluorescence is visualized in red and
cathepsin B in green (E), and these are shown both separately and as a merged image. Sections were additionally stained
with PI (coloured blue) to visualize the nuclei (F).
Final model selected using Akaike information criteria. The model was
initially fitted with all variables (Table 1), including Stefin A staining.

CONCLUSIONS
In a multivariate disease-free survival analysis (Cox proportional hazards
model), Stefin A expression remained a significant independent prognostic factor
in patients with invasive ductal carcinoma (p = 0.0014), along with grade and
progesterone receptor (PR) status.
We propose that Stefin A, as a cysteine cathepsin inhibitor, may be a marker of
increased cathepsin activity in metastases.
Using immunohistology, the cathepsin inhibitor was detected co-expressed with
cathepsin B in lung and bone metastases in both the murine model and human
tissues.
We conclude that Stefin A expression reduces distant metastasis in breast cancer
and propose that this may be due to the inhibition of cysteine cathepsins, such as
cathepsin B.

Multi-step mammary tumor progression
C3(1) SV40 Tag Transgenic Model
NL Dysplasia DCIS Inv Ca Met Ca
1 month
p53 + Rb
Inactivation
6 months
(100% Incidence)
? ? ?
Maroulakou et al. Proc. Natl. Acad. Sci. USA 91:11236, 1994

Categorización de los Eventos
Moleculares en Cáncer de Mama
Porteros: BRCA, p53, Rb
Esporádicos: HER-2/neu, c-myc, ras
Otros: Bcl-2, Hsps, ciclinas, VEGF
Daño al ADN,
alteración ciclo celular
Mayor estímulo para
crecimiento
Falla apoptosis, y otras
moléc., angiogénesis

Carga
genética Daños innatos al ADN
Daños adquiridos
Fallas controles de proliferación
Fallas controles de apoptosis
Edad
Cáncer
Declinación de la inmunidad
Cambios hormonales
Disminución mecanismos reparativos
Acumulación de daños al genoma/proteoma