Alpha Lipoic Acid (ALA) Inhibits the Anti-Myeloma Effects of Bortezomib
Jeffrey Steinberg,1 Jing Shen,1 Eric Sanchez,1 Haiming Chen,1 Zhi-Wei Li,1 Jacqueline Hilger,2 and James R. Berenson1
1Institute for Myeloma & Bone Cancer Research, West Hollywood, CA, USA; 2Millennium Pharmaceuticals, Inc., Cambridge, MA, USA
Abstract
Methods
Alpha Lipoic acid (ALA) is an antioxidant often used in the
MM cell lines RPMI8226 and MM1S (1x105 cells per 100µl) were treated with ALA alone to
management of peripheral neuropathy (PN) for patients
determine whether ALA had any effects on their growth as determined with an MTS assay.
MM1S
with multiple myeloma (MM). A clinical trial evaluating ALA
MM cells were plated in a 96-well plate using serum-free media. The cells were treated with
in diabetic neuropathy showed this drug to be effective for
125
either media alone or ALA at concentrations ranging from 1 to 1000 M for 48 hours. The
patients with both somatic and autonomic neuropathies. It
acidity of ALA at these doses was determined and if the pH was less than 7, it was neutralized
also normalized the endoneural blood flow, reduced
with NaOH to achieve a pH of 7. We then measured the proliferation of cells exposed to
l) 100
ro
oxidative stress and improved vascular dysfunction.
bortezomib alone, and combinations of a fixed concentration of bortezomib and escalating
ont
Bortezomib (Velcade ®), the first-in-class proteasome
concentrations of ALA.
c
75
%
inhibitor (PI), which is approved for the treatment of patients
(
lls
with MM, may cause PN. As a result, patients are often
Results
e
50
C
treated empirically with ALA. In this study, we investigated
leb
whether ALA has any impact on the anti-MM effects of
iaV 25
bortezomib. The exposure of MM cells to ALA alone had a
ALA Diminishes Bortezomib's Anti-MM Activity In Vitro
stimulatory effect on the growth of MM cell lines (RPMI8226
0
and MM1S) in vitro. ALA alone at 1000 mM resulted in an
Bortezomib (nM)
0
20
0
20
20
0
20
20
0
20
20
0
20
increase in cell viability of MM1S cells by approximately
ALA (M)
0
0
1
1
0
10
10
0
100
100
0
1000 1000
10% when compared to the control group. ALA alone also
RPM I-8226
stimulated the growth of RPMI8226 cells but at much lower
275
concentrations than observed for MM1S. Compared to
250
untreated cells, there was an increase in cell viability with
225
l)
ALA at concentrations as low as 1 mM and a concentration
ro 200
ont
dependent increase at concentrations of 1, 10, 100, and
175
c
B. MM1S multiple myeloma cells were exposed to escalating concentrations of bortezomib
%
1000mM in RPMI8226 cells. At the highest concentration
150
(
alone, ALA alone or in combination as indicated in the figure to the left. Cell viability was
lls 125
(1000 mM) of ALA, cell viability increased 150% when
e
determined with the MTS assay.
C 100
compared to RPMI8226 cells incubated with media alone.
le
75
iab
The combination of ALA, at a clinically achievable concentration of 100 M, plus bortezomib
Next, we evaluated the effect of ALA on bortezomib's anti-
V
50
exhibited less inhibition of MM growth compared to bortezomib alone.
MM activity. As a single agent, bortezomib reduced MM1S
25
(20 nM) and RPMI8226 (5 nM) cell viability by 93% and
0
70%, respectively. When ALA was added at a clinically
Bortezomib (nM)
0
5
0
5
5
0
5
5
05
5
0
5
ALA (M)
0
0
1
1
0
10 10
0
100
100
0
1000
1000
Conclusions
achievable concentration (100 mM) to bortezomib
(RPMI8226, 5 nM; MM1S, 20 nM), a reduction in the anti-
Our data suggest that ALA has the potential to antagonize the anti MM effects of bortezomib
MM effects of bortezomib on these cell lines was observed
based on our in vitro results using MM cell lines. Thus, it is possible that ALA could
when compared to bortezomib treatment alone. Compared
negatively impact the therapeutic benefit of bortezomib for MM patients, and this requires
to bortezomib alone, the combination of ALA plus
A. RPMI 8226 multiple myeloma cells were exposed to the indicated
further study especially if ALA is accepted as an intervention in bortezomib-related
bortezomib doubled cell viability (increased RPMI8226 and
concentrations of bortezomib alone, ALA alone, and in combination, and then cell
neuropathy. We are currently completing studies evaluating primary MM patients' tumor
MM1S cell viability from 32.5% to 65% and 7.5% to 15%,
viability was determined using the MTS assay.
cells in vitro and our human MM xenograft models in vivo to further validate this impact of
respectively). These negative effects of ALA on
ALA on bortezomib's anti-MM activity, and whether changes in treatment schedule of these
The combination of ALA, at a clinically achievable concentration of 100 M, plus
bortezomib's anti-MM activity were consistently observed in
drugs may prevent this inhibitory effect from occurring. In addition, because part of
bortezomib exhibited less inhibition of MM growth compared to bortezomib alone.
multiple experiments involving both of these cell lines
bortezomib's anti-tumor effects are related to reactive oxygen species (ROS) levels, we are
evaluating concentrations of ALA ranging from 100 to 1000
evaluating whether the inhibitory effects of ALA on this PI may be overcome by increasing
mM and bortezomib ranging from 5 to 20 nM.
intracellular ROS levels.
Poster # III-768
Author Disclosures: This work was funded by a research grant provided by Millennium

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