Courtney Shirley

JJ Gills

Nene Kalu

Richard Ambinder

Infectious Agents and Cancer

English

PubMed

Springer - Publisher Connector

POSTER PRESENTATION Open Access
ER stress activates lytic gene expression in KSHV-
associated tumor cell lines
Nene Kalu1*, Courtney Shirley2, Richard Ambinder2
From 13th International Conference on Malignancies in AIDS and Other Acquired Immunodeficiencies
(ICMAOI)
Bethesda, MD, USA. 7-8 November 2011
Background
Activating the herpesvirus lytic replication cycle presents
an opportunity for targeted therapy. We explored the
effects of endoplasmic reticulum (ER) stress inducers on
Kaposi’s sarcoma herpesvirus (KSHV) lytic activation in
primary effusion lymphoma (PEL) cell lines. We included
nelfinavir (an HIV-1 protease inhibitor) in our investiga-
tions because it has been reported to induce ER stress in
various tumor cell lines [1]. Treatment with bortezomib,
thapsigargin or nelfinavir resulted in increased expression
of ER stress markers such as activating transcription fac-
tor 4 (ATF-4) and the spliced form of X-box binding pro-
tein 1 (XBP-1(s) (see figure 1). Treatment was also
associated with an increase in RNA expression of the
KSHV immediate early “replication and transcriptional
activator” (RTA) (see figure 2). To determine whether ER
stress mediated KSHV lytic reactivation associated with
these agents, we prepared doxycycline-activated short
hairpin RNA knockdowns of ER stress genes (Grp78 and
XBP-1(s)). Treatment of these knockdowns with doxycy-
cline for 72 hours resulted in inhibition of ER stress and
inhibition of viral lytic gene expression.
Conclusion
These results demonstrate that in KSHV-infected cell
lines, induction of ER stress is associated with activation
* Correspondence: nidika@gmail.com
1Department of Pharmacology and Molecular Sciences, Johns Hopkins
School of Medicine, Baltimore, MD, USA
Full list of author information is available at the end of the article
Figure 1 Treatment of BC-3 cells leads to induction of ER stress markers. KSHV PEL cells (BC-3) were treated with DMSO, 20nM bortezomib
(20nm BZ), 1mM thapsigargin (1mM TG) or 72uM nelfinavir (72uM NFV). RNA was isolated and RT-PCR was performed using primers for ATF-4
and XBP-1(s). Primers for b-actin were used as an internal control. Error bars indicate SEM.
Kalu et al. Infectious Agents and Cancer 2012, 7(Suppl 1):P33
http://www.infectagentscancer.com/content/7/S1/P33
© 2012 Kalu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
of KSHV lytic genes and raises the possibility that nelfi-
navir might be incorporated into future treatment stra-
tegies for KSHV-associated malignancies.
Author details
1Department of Pharmacology and Molecular Sciences, Johns Hopkins
School of Medicine, Baltimore, MD, USA. 2Department of Oncology, Johns
Hopkins School of Medicine, Baltimore, MD, USA.
Published: 19 April 2012
Reference
1. Gills JJ, Lopiccolo J, Tsurutani J, Shoemaker RH, Best CJ, Abu-Asab MS,
Borojerdi J, Warfel NA, Gardner ER, Danish M, et al: Nelfinavir, a lead HIV
protease inhibitor, is a broad spectrum, anticancer agent that induces
endoplasmic reticulum stress, autophagy and apoptosis in vitro and in
vivo. Clin Cancer Res 2007, 13:5183-5194.
doi:10.1186/1750-9378-7-S1-P33
Cite this article as: Kalu et al.: ER stress activates lytic gene expression
in KSHV-associated tumor cell lines. Infectious Agents and Cancer 2012 7
(Suppl 1):P33.
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Figure 2 ER stress inducers activate KSHV lytic gene expression.
KSHV BC-3 cells were treated with DMSO, 20nM bortezomib (20nm
BZ), 1mM thapsigargin (1mM TG) or 72uM nelfinavir. RNA was
isolated and RT-PCR was performed using primers for RTA. Primers
for b-actin were used as an internal control. Error bars indicate SEM.
Kalu et al. Infectious Agents and Cancer 2012, 7(Suppl 1):P33
http://www.infectagentscancer.com/content/7/S1/P33
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ER stress activates lytic gene expression in KSHV-associated tumor cell lines

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Nelfinavir, a lead HIV protease inhibitor, is a broad spectrum, anticancer agent that induces endoplasmic reticulum stress, autophagy and apoptosis in vitro and in vivo. Clin Cancer Res

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ER stress activates lytic gene expression in KSHV-associated tumor cell lines

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