Transcript IGH

VIRUSES AND NUCLEAR ORGANIZATION IN ONCOGENESIS
Yegor VASSETZKY, CNRS UMR 8126, Institut de Cancérologie Gustave Roussy
VIRAL THEORY OF CANCER: UPS AND DOWNS
Peyton Rouss
1911: discovery of RSV
1966: Nobel Prize
Denis Burkitt
1957: discovery of
Burkitt’s lymphoma
Anthony Epstein
Yvonne Barr
1964: discovery of EBV in Burkitt’s lymphoma
samples
BURKITT’S LYMPHOMA
A non-Hodgkin Lymphoma
Three forms:
 An endemic form in Afrtica is 100% associated with EBV
 A sporadic form in Europe and North America, rare and non-associated with EBV
 A form associated with HIV is frequent in Europe and is found in up to 2% (!) of
AIDS patients
In ~90% of the cases BL is linked to the translocation t(8;14)(q24;q32) of the CMYC gene
locus next to the IGH gene locus leading to activation of the CMYC gene.
HIGH OCCURRENCE OF BURKITT’S LYMHOMA IN HIV
PATIENTS: WHY?
 gp-120 can
Cancer
interact
withinCD21
Frequency
the
Frequency in
expressed on B cells
(Moir etpoplation
al 2000)
general
AIDS patients
 HIV-1 causes B-cell hyperactipvation
Burkitt’s
1:200 000
1: 4000
(Schnittan et al,1984)
Lymphoma
 Elevated class switch in B lymphocytes
Mantle
Cell B cell to proliferate
1:200 000(Nair MPN 1:200 000
 Induces
Lymphoma
and al 1988)
 Causes B cell abnormal response
Three
areofnecessary
to produce a translocation:
 The events
production
autoantibodies
 Aberrant B-cell surface markers:
DNA double strand breaks (Vilenchik et Knudson, 2003).
Change in B cell receptors.
Ratio
50
1
Double strand breaks repair via NHEJ (Abeysinghe et al., 2003).
Spatial proximity (colocalization) of the two translocation partners. (Nikiforova et al., 2000, Misteli,
2003).
Shen ,2011
CHROMOSOMAL TERRITORIES
Theodor Boveri (1862-1915)
Carl Rabl (1853-1917)
Bolzer et al., PlosBiology (2005), 3 (5) e207
 The chromosomes are organized in the nucleus:
In
Bolzer et al., Plos Biology (2005), 3 (5) e207
a tissue specific manner
The
This
organization is transmitted though the cell divisions
organization is evolutionarily conserved
 The gene-rich regions occupy more central position in the nucleus
NUCLEAR ARCHITECTURE
HIV: A ROLE IN RELOCALIZATION OF C-MYC INTO REGIONS
PROXIMAL TO IgH?
Periphery
C-MYC
Topro 3
IGH
Centre
Normal B-Lymphocytes:
IGH/CMYC proximity in ~3% of cells
HIV PROVOKES A RELOCALIZATION OF A CMYC LOCUS IN
THE NUCLEAR SPACE AND ITS COLOCALIZATION WITH IgH
CMYC
Topro 3
IGH
3µm
HIV GENOME
 9 genes encoding 3 structural, 2 envelope, and 6 regulatory proteins in addition to 3
enzymes
 TAT – transactivator of transcription encoded by 2 different exons. The 102 aa Tat is
responsible for activation of viral Tat is secreted into the circulation and is capable to
penetrate into cells. Produced in excess in infected cells. Tat is present in blood of
AIDS patients.
HIV Tat PROVOKES A SPECIFIC COLOCALIZATION OF THE
IGH AND CMYC LOCI IN THE NUCLEAR SPACE OF B CELLS
Cancer
Frequency in the
general poplation
Frequency in
AIDS patients
Ratio
Burkitt’s
000colocalization 1:
50colocalization in
Tat induces a dose-dependent1:200
CMYC/IGH
Tat 4000
does not induce CMYC/IGH
macrophages and T cells
Lymphoma
Mantle Cell
Lymphoma
1:200 000
1:200 000
Tat does not induce IGH/b -globin or IGH/CCND1 colocalization in B lymphocytes
1
IGH/CMYC COLOCALIZATION IN AIDS PATIENTS
TRANSACTIVATION DOMAIN OF HIV Tat IS REQUIRED TO
INDUCE COLOCALIZATION OF IGH AND CMYC AND
ACTIVATE CMYC TRANSCRIPTION
RNA pol2
CMYC
IGH
30
MERGE
MRE11
CMYC
IGH
Nucleus
IGH/CMYC COLOCALIZATION IS NHEJ-DEPENDENT
HIV TAT INDUCES DNA DAMAGE IN B-LYMPHOCYTES
% of cells with gH2AX/CMYC Colocalization
% of cells with gH2AX foci @ 6h
HIV TAT INDUCES DNA DAMAGE IN THE CMYC LOCUS
***
***
Nucleus
CMYC
***
ns
gH2ax
Merge
RAG1 IS INDUCED BY TAT AND IS ESSENTIAL FOR
IGH/CMYC COLOCALIZATION
ns
RAG1/2
AID
*
ns
NFkB PATHWAY AND ITS REGULATION BY HIV TAT
ikBa phosphorylation @ 1h
HIV Tat
Li & Verma, 2002
**
ns
HIV: A ROLE IN INTRANUCLEAR REORGANIZATION AND IN
GENERATION OF SPECIFIC TRANSLOCATIONS
HIV
EBV
IgH
c-myc
HIV Tat
 NFkB  RAG  DSB  NHEJ CMYC relocalization
T
Tat C22
Transription
T
RAGi
T
Mirin
NU7026
Nuclear Organization and Pathologies Lab (UMR-8126, IGR, Villejuif, France):
Marc Lipinski, DR CNRS
Chrystèle Bilhou-Nabera, MCU-PH
Diego Germini, postdoctorant
Tatiana Tsfasman, postdoctorante
Yara Bou Saada, doctorante UPS
Shirmoné Botha, doctorante
Anatasia Sukhanova, M1
Rawan El-Amine, doctorante (cotutelle Liban)
Carla Dib, doctorante
Eric Oksenhendler, HSL, Paris
Sergey Razin, IBG, Moscow
Olga Iarovaya, IBG, Moscow
Evgeny Sheval, MSU, Moscow
S. Bury-Moné, ENS Cachan