Introduction: Tryptophan metabolism has been shown to be involved in tumor development. Two main tryptophan-degrading enzymes, tryptophan 2,3-dioxygenase (TDO2) and indoleamine 2,3-dioxygenase 1 (IDO1), may potently promote cancer cell survival and distant metastasis in diverse types of cancer, such as lung and breast cancer. IDO1 overexpression is an independent prognosticator in gastric cancer (GC). This work aimed to uncover the expression of TDO2 and its clinicopathologic significance in GC. Methods: TDO2 expression was evaluated in public data of The Cancer Genome Atlas cohort STAD and in two different GC cohorts. Correlation between TDO2 and immune cell infiltrates as well as PD-L1 tumor staining was investigated. The biofunction of TDO2 was examined with MTT, colony formation, and spheroid formation assays by RNA interference. Results: TDO2 expression was correlated with both progressive disease and clinical outcome, and its expression was an independent predictor of prognosis in GC. TDO2 expression was correlated with infiltration of immune cells and tumor expression of PD-L1. Inhibition of TDO2 expression suppressed cell proliferation, colony formation, and cell invasion of GC cells. Additionally, suppression of TDO2 expression inhibited spheroid body-formation and viability of GC organoids. Conclusion: Our data show that TDO2 might be a crucial marker for predicting prognosis and targeted therapy in GC.

1.
Bray
F
,
Ferlay
J
,
Soerjomataram
I
,
Siegel
RL
,
Torre
LA
,
Jemal
A
.
Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries
.
CA Cancer J Clin
.
2018
;
68
(
6
):
394
424
.
2.
Services CfCCaI
.
Cancer statistics: National Cancer Center
.
2020
. Available from: http://ganjoho.jp/reg_stat/statistics/index.html.
3.
Cancer Genome Atlas Research Network
.
Comprehensive molecular characterization of urothelial bladder carcinoma
.
Nature
.
2014
;
507
(
7492
):
315
22
.
4.
Tirino
G
,
Pompella
L
,
Petrillo
A
,
Laterza
MM
,
Pappalardo
A
,
Caterino
M
,
.
What’s new in gastric cancer: the therapeutic implications of molecular classifications and future perspectives
.
Int J Mol Sci
.
2018
;
19
(
9
):
2659
.
5.
Katai
H
,
Ishikawa
T
,
Akazawa
K
,
Isobe
Y
,
Miyashiro
I
,
Oda
I
,
.
Five-year survival analysis of surgically resected gastric cancer cases in Japan: a retrospective analysis of more than 100,000 patients from the nationwide registry of the Japanese Gastric Cancer Association (2001–2007)
.
Gastric Cancer
.
2018
;
21
(
1
):
144
54
.
6.
Xin Yu
J
,
Hodge
JP
,
Oliva
C
,
Neftelinov
ST
,
Hubbard-Lucey
VM
,
Tang
J
.
Trends in clinical development for PD-1/PD-L1 inhibitors
.
Nat Rev Drug Discov
.
2020
;
19
(
3
):
163
4
.
7.
Kono
K
,
Nakajima
S
,
Mimura
K
.
Current status of immune checkpoint inhibitors for gastric cancer
.
Gastric Cancer
.
2020
;
23
(
4
):
565
78
.
8.
Martinez-Outschoorn
UE
,
Peiris-Pagés
M
,
Pestell
RG
,
Sotgia
F
,
Lisanti
MP
.
Cancer metabolism: a therapeutic perspective
.
Nat Rev Clin Oncol
.
2017
;
14
(
1
):
11
31
.
9.
Counihan
JL
,
Grossman
EA
,
Nomura
DK
.
Cancer metabolism: current understanding and therapies
.
Chem Rev
.
2018
;
118
(
14
):
6893
923
.
10.
Cheong
JE
,
Sun
L
.
Targeting the IDO1/TDO2-KYN-AhR pathway for cancer immunotherapy: challenges and opportunities
.
Trends Pharmacol Sci
.
2018
;
39
(
3
):
307
25
.
11.
Platten
M
,
Nollen
EAA
,
Röhrig
UF
,
Fallarino
F
,
Opitz
CA
.
Tryptophan metabolism as a common therapeutic target in cancer, neurodegeneration and beyond
.
Nat Rev Drug Discov
.
2019
;
18
(
5
):
379
401
.
12.
Tang
D
,
Yue
L
,
Yao
R
,
Zhou
L
,
Yang
Y
,
Lu
L
,
.
P53 prevent tumor invasion and metastasis by down-regulating IDO in lung cancer
.
Oncotarget
.
2017
;
8
(
33
):
54548
57
.
13.
Hsu
YL
,
Hung
JY
,
Chiang
SY
,
Jian
SF
,
Wu
CY
,
Lin
YS
,
.
Lung cancer-derived galectin-1 contributes to cancer associated fibroblast-mediated cancer progression and immune suppression through TDO2/kynurenine axis
.
Oncotarget
.
2016
;
7
(
19
):
27584
98
.
14.
Smith
C
,
Chang
MY
,
Parker
KH
,
Beury
DW
,
DuHadaway
JB
,
Flick
HE
,
.
IDO is a nodal pathogenic driver of lung cancer and metastasis development
.
Cancer Discov
.
2012
;
2
(
8
):
722
35
.
15.
D’Amato
NC
,
Rogers
TJ
,
Gordon
MA
,
Greene
LI
,
Cochrane
DR
,
Spoelstra
NS
,
.
A TDO2-AhR signaling axis facilitates anoikis resistance and metastasis in triple-negative breast cancer
.
Cancer Res
.
2015
;
75
(
21
):
4651
64
.
16.
Liu
H
,
Shen
Z
,
Wang
Z
,
Wang
X
,
Zhang
H
,
Qin
J
,
.
Increased expression of IDO associates with poor postoperative clinical outcome of patients with gastric adenocarcinoma
.
Sci Rep
.
2016
;
6
(
1
):
21319
.
17.
Pham
QT
,
Oue
N
,
Sekino
Y
,
Yamamoto
Y
,
Shigematsu
Y
,
Sakamoto
N
,
.
TDO2 overexpression is associated with cancer stem cells and poor prognosis in esophageal squamous cell carcinoma
.
Oncology
.
2018
;
95
(
5
):
297
308
.
18.
Edge
SB
,
Compton
CC
.
The American Joint Committee on Cancer: the 7th edition of the AJCC cancer staging manual and the future of TNM
.
Ann Surg Oncol
.
2010
;
17
(
6
):
1471
4
.
19.
Pham
QT
,
Oue
N
,
Yamamoto
Y
,
Shigematsu
Y
,
Sekino
Y
,
Sakamoto
N
,
.
The expression of BTS-2 enhances cell growth and invasiveness in renal cell carcinoma
.
Anticancer Res
.
2017
;
37
(
6
):
2853
60
.
20.
Sentani
K
,
Imai
T
,
Kobayashi
G
,
Hayashi
T
,
Sasaki
N
,
Oue
N
,
.
Histological diversity and molecular characteristics in gastric cancer: relation of cancer stem cell-related molecules and receptor tyrosine kinase molecules to mixed histological type and more histological patterns
.
Gastric Cancer
.
2021
;
24
(
2
):
368
81
.
21.
Vasaikar
SV
,
Straub
P
,
Wang
J
,
Zhang
B
.
LinkedOmics: analyzing multi-omics data within and across 32 cancer types
.
Nucleic Acids Res
.
2017
;
46
(
D1
):
D956
63
.
22.
Colaprico
A
,
Silva
TC
,
Olsen
C
,
Garofano
L
,
Cava
C
,
Garolini
D
,
.
TCGAbiolinks: an R/Bioconductor package for integrative analysis of TCGA data
.
Nucleic Acids Res
.
2015
;
44
(
8
):
e71
.
23.
Arienti
C
,
Pignatta
S
,
Tesei
A
.
Epidermal growth factor receptor family and its role in gastric cancer
.
Front Oncol
.
2019
;
9
:
1308
.
24.
Quoc Thang
P
,
Daiki
T
,
Yohei
S
,
Shintaro
A
,
Takashi
B
,
Go
K
,
.
BMC Cancer
.
2021
.
25.
Sumitomo
M
,
Takahara
K
,
Zennami
K
,
Nagakawa
T
,
Maeda
Y
,
Shiogama
K
,
.
Tryptophan 2,3-dioxygenase in tumor cells is associated with resistance to immunotherapy in renal cell carcinoma
.
Cancer Sci
.
2021
;
112
(
3
):
1038
47
.
26.
Doi
T
,
Piha-Paul
SA
,
Jalal
SI
,
Saraf
S
,
Lunceford
J
,
Koshiji
M
,
.
Safety and antitumor activity of the anti-programmed death-1 antibody pembrolizumab in patients with advanced esophageal carcinoma
.
J Clin Oncol
.
2018
;
36
(
1
):
61
7
.
27.
Böger
C
,
Behrens
HM
,
Mathiak
M
,
Krüger
S
,
Kalthoff
H
,
Röcken
C
.
PD-L1 is an independent prognostic predictor in gastric cancer of Western patients
.
Oncotarget
.
2016
;
7
(
17
):
24269
83
.
28.
Tahara
T
,
Shibata
T
,
Okamoto
Y
,
Yamazaki
J
,
Kawamura
T
,
Horiguchi
N
,
.
Mutation spectrum of TP53 gene predicts clinicopathological features and survival of gastric cancer
.
Oncotarget
.
2016
;
7
(
27
):
42252
60
.
29.
Ye
MX
,
Zhang
Y
,
Gao
HJ
,
Xu
Y
,
Jing
PY
,
Wu
JX
,
.
Activation of the aryl hydrocarbon receptor leads to resistance to EGFR TKIs in non-small cell lung cancer by activating src-mediated bypass signaling
.
Clin Cancer Res
.
2018
;
24
(
5
):
1227
39
.
30.
Li
L
,
Wang
T
,
Li
S
,
Chen
Z
,
Wu
J
,
Cao
W
,
.
TDO2 promotes the EMT of hepatocellular carcinoma through Kyn-AhR pathway
.
Front Oncol
.
2021
;
10
:
562823
.
31.
Opitz
CA
,
Litzenburger
UM
,
Sahm
F
,
Ott
M
,
Tritschler
I
,
Trump
S
,
.
An endogenous tumour-promoting ligand of the human aryl hydrocarbon receptor
.
Nature
.
2011
;
478
(
7368
):
197
203
.
32.
Pilotte
L
,
Larrieu
P
,
Stroobant
V
,
Colau
D
,
Dolusic
E
,
Frederick
R
,
.
Reversal of tumoral immune resistance by inhibition of tryptophan 2,3-dioxygenase
.
Proc Natl Acad Sci U S A
.
2012
;
109
(
7
):
2497
502
.
33.
Batlle
E
,
Clevers
H
.
Cancer stem cells revisited
.
Nat Med
.
2017
;
23
(
10
):
1124
34
.
34.
Najafi
M
,
Mortezaee
K
,
Majidpoor
J
.
Cancer stem cell (CSC) resistance drivers
.
Life Sci
.
2019
;
234
:
116781
.
35.
Takaishi
S
,
Okumura
T
,
Tu
S
,
Wang
SSW
,
Shibata
W
,
Vigneshwaran
R
,
.
Identification of gastric cancer stem cells using the cell surface marker CD44
.
Stem Cells
.
2009
;
27
(
5
):
1006
20
.
36.
Bartfeld
S
,
Clevers
H
.
Stem cell-derived organoids and their application for medical research and patient treatment
.
J Mol Med
.
2017
;
95
(
7
):
729
38
.
37.
Ukai
S
,
Honma
R
,
Sakamoto
N
,
Yamamoto
Y
,
Pham
QT
,
Harada
K
,
.
Molecular biological analysis of 5-FU-resistant gastric cancer organoids; KHDRBS3 contributes to the attainment of features of cancer stem cell
.
Oncogene
.
2020
;
39
(
50
):
7265
78
.
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