Tumor Metabolism and
Chemotherapy Resistance
Glutamine a Paradox
Michael B. Sawyer, MD, B.Sc. Phm.
Associate Professor, Division of Medical Oncology
FRCPC (Int. Medicine & Medical Oncology)
Dip.ABIM (Int. Medicine & Medical Oncology)
Dip.American Board of Clinical Pharmacology
Fellow American College of Clinical Pharmacology
Potential Conflict of Interest
• Dr. Michael Sawyer
– Abraxis, research funding (2006-present)
– AstraZeneca, research funding (2006-present)
– Roche research funding (2005-present)
Outline
• In vitro glutamine research
• In vivo glutamine research
• Clinical glutamine research
– Oxaliplatin neuropathy and glutamine
• Future Research
– Translational research into glutamine and oxaliplatin
What is Glutamine
•
•
•
•
In health non essential amino acid
Conditionally essential amino acid in illness
Preferred fuel for enterocytes and immune cells
Precursor for glutathione – major cellular
antioxidant
• Involved in interorgan nitrogen exchange and
maintenance of pH homeostasis
Altered Metabolism in Cancer Cells
• Warburg noted aerobic gycolysis in 1927
• Glutamine similarly appeared to be metabolized
inefficiently
• Many cancer cell lines appear to have a “glutamine”
addiction
– Withdrawal of glutamine causing cell death
– Withdrawal of glutamine and substitution of alpha
ketoglutarate rescues the cells from death but does not
allow proliferation
Altered Metabolism in Cancer Cells
• Activation of the oncogene Myc activates many enzymes
in glutamine metabolism
– Glutamine transporters SLC38A5 and SLC1A5
– Glutaminase that converts glutamine to glutamate
releasing free ammonia
• Glutamine replenishes alpha ketoglutarate
• Provides NADPH for biosynthetic reactions
• Provides nitrogen for synthesis of non essential amino
acids
Putative in vitro role of gln
In Vivo Glutamine Models
• Surgeons and radiation oncologists have not
had these concerns
• Klimberg, Rombeau and Coupland have studied
glutamine in multiple in vivo models
• Radiation immunotherapy and methotrexate
• Demonstrated increased natural killer cell
activity, decreased tumor glutathione,
increased efficacy and decreased toxicity
Hypothesis
• Postulated that glutamine supplementation would
improve the therapeutic index of irinotecan
• Glutamine would decrease reduced glutathione in tumor cells
• Glutamine would increase reduced glutathione in normal
tissues such as the intestine decreased chemo toxicity
• Gln would not increase heat shock proteins in the tumor
• Gln would increase heat shock proteins in normal tissues
• Overall glutamine would increase the efficacy of
chemotherapy in the tumor and decrease the toxicity of
chemotherapy in the normal tissues
Dietary treatments
• Treatment groups
Control diet
Prebiotic enriched diet
Fish oil enriched diet
Bolus glutamine
+
irinotecan
125mg/kg×3days
N=8-12 for each treatment group
• Timeline
-28
Control, prebiotic, fish oil diets start
irinotecan
1, 2, 3
Glutamine bolus
Day
Comparison of Effects of Different Dietary
Treatments on Irinotecan-Induced Diarrhea
diarrhea scoring
3.5
control diet + irinotecan
3
Gln bolus + irinotecan
2.5
prebiotics + irinotecan
fish oil + irinotecan
2
1.5
1
0.5
0
Time (day)
0
2
4
6
8
10
Comparison of Effects of Different Dietary
Treatments on Irinotecan-Induced Diarrhea
Incidence of severe diarrhea
0.7
incidence
0.6
0.5
*
0.4
0.3
0.2
0.1
0
control
Gln bolus
prebiotic
fish oil
Does Glutamine Treatment Potentiate
HSP Response in Tumor as Well?
Control diet Gln bolus
+ + irinotecan + irinotecan
Hsp70
Hsp27
control diet+irinotecan
Gln bolus+irinotecan
control diet+irinotecan
Gln bolus+irinotecan
Hsp90α
Gln Bolus vs. Control- Colonic Mucosa
Control diet
+ irinotecan
Gln bolus
+ irinotecan
*
*
Hsp70
contro diet+irinotecan
Gln bolus+irinotecan
*
*
Hsp27
control diet+irinotecan
Gln bolus+irinotecan
*
Hsp90α
*
control
diet+irinotecan
Gln bolus+irinotecan
Hsc70
control
diet+irinotecan
Gln bolus+irinotecan
Dietary Effects on Irinotecan/5FU Efficacy
Dietary Effects on Normal Tissue GSH/GSSG
Dietary treatment
total GS H*
GS S G
re du ce d GS H
GS H/GS S G
REF
1.86±0.12
0.014±0.0021
1.83±0.12
135.59±12.6
CON
1.65±0.057
0.033±0.011
1.58±0.054
¤
67.66±17.59
GLN
1.57±0.097
0.012±0.001
1.55±0.097
136.22±13.33
FO
1.72±0.12
0.015±0.003
1.69±0.11
GLN/FO
1.74±0.062
0.0153±0.0016
1.71±0.062
117.92±13.23
0.772
0.047
0.950
0.041
0.181
0.162
0.133
0.192
0.613
0.041
0.782
0.016
Glutamine
124.33±12. 97 2-way
N-3 fat ty
ANOVA
acids
p value
Interaction
Dietary Effects on Tumor Tissue GSSG/GSH
Dietary treatment
total GS H
GSSG
re du ce d GSH
GSH/GSSG
CON
1.56±0.095
0.017±0.0029
1.52±0.090
98.61±14.86
GLN
1.2±0.17
0.024±0.0043
1.15±0.16
54.97±10.05
FO
1.26±0.14
0.023±0.0045
1.22±0.14
58.59±11.03
GLN/FO
1.096±0.12 0.028±0.0056
1.04±0.12 47.17±12.52 0.090
0.231
0.073
0.035
0.188
0.264
0.160
0.063
0.529
0.787
0.511
0.197
Glutamine
2-way
N-3 fat ty
ANOVA
acids
p value
Interaction
Wang et al.
• 86 metastatic colorectal cancer patients
• Randomized to glutamine (n=42) or control
group (n=44)
• Treated with oxaliplatin (85) mg/m2 days 1 and
15 and weekly 5-flurouracil (5-FU; 500 mg/m2)
and folinic acid (FA 20 mg/m2) on days 1, 8, and
15
• Glutamine was administered 15 g twice a day
for 7 days every two weeks
Incidence of oxaliplatin-induced neuropathy in different patient groups
Wang, W.-S. et al. Oncologist 2007;12:312-319
Outcome of oral glutamine supplementation
Wang, W.-S. et al. Oncologist 2007;12:312-319
Table 4. Response to oxaliplatin-based chemotherapy in different patient groups
Wang, W.-S. et al. Oncologist 2007;12:312-319
Copyright ©2007 AlphaMed Press
Survival curves of metastatic colorectal cancer patients receiving (filled circle) or not receiving (open
circle) glutamine supplementation during oxaliplatin treatments plotted by the Kaplan-Meier method
(p = .788; log-rank test)
Wang, W.-S. et al. Oncologist 2007;12:312-319
Wang Study Interpretations
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Hard endpoint: survival
Not placebo controlled
No pharmacokinetics
Did not look at diarrhea
No mechanism of action
– No glutathione levels
– No HSP
• Started the day of chemotherapy
Sanofi’s Glutox Study
• Using FOLFOX
• Randomized placebo controlled
• Starting glutamine/placebo two days before
chemotherapy
• Looking at diarrhea
Cross Cancer Parallel Glutox
• Patients randomized to glutamine first cycle or
second cycle
• Oxaliplatin pharmacokinetics done in cycle 1
and 2
• Measurement of plasma, red blood cell
glutathione (GSSG and GSH) levels in cycle 1
and 2
• Measurement of white blood cell heat shock
protein levels
Take Home Messages
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Translational research matters
In vitro models may not hold up in in vivo models
In vitro models may not hold to human clinical trials
Cancer cells are model systems
An isolated cancer cell is not a syngenic tumor graft
nor a human cancer patient
Acknowledgments
• Hongyu Xue MD PhD
• Co-Principal Investigators:
Dr. Vickie Baracos
Dr. Catherine Field
Dr. Leo Dieleman
Alberta Health Services
Cancer Care
Lab members:
Abha Hoedl
Michelle Mackenzie
Dr. Marina Mourtzakis
Stephanie Best
Sue Goruk
Celine
CCI vivarium staff
Glutamine Effects on -Glucuronidase
vs. control diet + irinotecan
Stress response study