Screening key differentially expressed genes related with poor progression and vascular invasion of HCC in TCGA
HCC patients in TCGA only contain both gene expression data and enough clinical information like pathological stage and vascular invasion were chosen in our study. Firstly, we divided 256 HCC patients into early stage HCC groups (stage I/II) and 90 HCC patients into advanced stage HCC groups (stage III/IV). However, 6 stage I/II HCC cases, 1 stage III/IV HCC case that lack of gene expression values and 24 HCC cases that lack of pathologic stage clinical information were excluded. What’s more, according to different vascular invasion clinical information, HCC patients were classified into none invasion-HCC groups (n=206) and vascular invasion-HCC groups (n=109). Vascular invasion-HCC groups containing 93 micro-vascular invasion-HCC patients and 16 macro-vascular invasion-HCC patients. 4 none invasion-HCC cases from a total of 210 none invasion-HCC, 1 micro-vascular invasion-HCC case from a total of 94 micro-vascular invasion-HCC, 1 macro-vascular invasion-HCC case from a total of 17 macro-invasion HCC that lose gene expression values and 56 HCC cases that lack of vascular invasion clinical information were also be discarded. Next, by using edgeR package in R software and set the |log2FC| > 1.5 and p values < 0.05 as restricted condition, we found 2279 DEGs were upregulated and 492 DEGs were downregulated in early stage HCC compared with normal liver tissues (Figure 2A and Table S1). Besides, 430 genes were found upregulated and 103 genes were found downregulated in advanced stage HCC in comparison with early stage HCC (Figure 2B and Table S2). In addition, 375 differentially expressed genes between none invasion-HCC and vascular invasion-HCC were discovered, including 285 upregulated and 90 downregulated genes (Figure 2C and Table S3). In this research, we aimed to analyze the hub genes related with the regulatory mechanism of the progression and the metastasis of HCC. Hence, 29 upregulated DEGs with consistency in three comparison sets were obtained, while no downregulated DEGs were found. Consequences were shown in Figure 2D-F. Finally, 29 hub genes were selected as candidate genes for further analysis.
Further prognosis and expression analysis found a hub gene: VCX3A in HCC
Subsequently, we using Kaplan-Meier plotter to investigate the prognostic values of 29 hub gens in HCC. As shown in Figure 3A-B, among 29 candidate DEGs, only 5 genes (VCX3A, PNCK, SLC6A3, MMP1, CTSE) show positively associations between high expression and significantly unfavorable overall survival (OS) in HCC patients. Whereas overexpression of HHATL, SOHLH1, CDH10, STAC2, NKX2-5, RNF151, CDK5R2, PHOX2A, HRK, TRIM63, KLK15, GAD2, ISL1, ATOH1, HOXD13, GPR50 show better OS in HCC. Furthermore, no significant relationships between the expression of PSCA, CALCA, DUOX2, CHST5 and their prognostic values in HCC were found. In addition, no prognostic values of CXorf67, NAT16, HNRNPCL3 and FOXL2NB were found in Kaplan-Meier plotter. Thus, we only selected VCX3A, PNCK, SLC6A3, MMP1, CTSE for the next analysis. Subsequently, for improving accuracy of our analysis, we intended to further evaluated the prognostic values of VCX3A, PNCK, SLC6A3, MMP1 and CTSE only in HCC patients with vascular invasion in TCGA. All the gene expression information and survival clinical information of HCC patients with vascular invasion in TCGA were extracted alone. Patients were divided into down-expression groups (n=54) and up-expression groups (n=55) according the median values of hub gene expressions. Finally, survival analyses were performed through GraphPad prism software (version 6). As the results presented in Figure 3C–G, only increased mRNA expressions of VCX3A and SLC6A3 contribute to worse OS in vascular invasion-HCC patients. However, no significant survival values of PNCK, MMP1 and CTSE were found. Lastly, we validated the expression values of VCX3A and SLC6A3 in 10 none-invasion liver tissues and 10 vascular invasion-HCC tumor tissues in clinical samples (Figure 3H-I). Notably, we found that VCX3A was high-expressed in tumor tissues than normal liver tissues, while for SLC6A3, no significant difference was discovered. In conclusion, VCX3A is supposed to be the most significant gene which plays function related with HCC progression and metastasis. Besides, clinical characteristics among VCX3A and HCC in TCGA also showed that high expression of VCX3A was more likely to cause vascular invasion in HCC patients (Table 1).
Table 1: Correlations the clinical characteristics among VCX3A and HCC in TCGA. (The significant P value is marked with Bold type. NA=Not Applicable.)
Variables
|
|
HCC
|
VCX3A
|
low/high expression case (n)
|
P value
|
Gender
|
N
|
|
Male
|
250
|
231/19
|
0.2079
|
Female
|
121
|
107/14
|
Age at diagnosis
|
|
|
|
>=60
|
201
|
179/22
|
0.1359
|
<60
|
169
|
158/11
|
NA
|
1
|
1/0
|
T stage
|
|
|
T1/T2
|
275
|
252/23
|
0.4858
|
T3/T4
|
93
|
83/10
|
TX
|
1
|
1/0
|
NA
|
2
|
2/0
|
|
N stage
|
|
|
N0
|
252
|
233/19
|
0.2792
|
N1
|
4
|
3/1
|
NX
|
114
|
101/13
|
NA
|
1
|
1/0
|
M stage
|
|
|
M0
|
266
|
245/21
|
1.0000
|
M1
|
4
|
4/0
|
MX
|
101
|
89/12
|
Pathologic stage
|
|
|
I/II
|
257
|
235/22
|
0.3081
|
III/IV
|
90
|
79/11
|
NA
|
24
|
24/0
|
Vascular invasion
|
|
|
None
|
206
|
194/12
|
0.0313
|
Micro/Macro
|
109
|
95/14
|
NA
|
56
|
49/7
|
Identifying hsa-miR-664a-3p-VCX3A axis play a key role in HCC
First, we predicted upstream miRNAs of VCX3A through TargetScan, miRWalk and miRDB three databases, since increasing studies have indicated that miRNAs take part in the invasion and metastasis of multiple tumors and play significant functions in cancer development [15-17]. As presented in Figure 4A-B, a total of 15 miRNAs (hsa-miR-2861, hsa-miR-5739, hsa-miR-4505, hsa-miR-6770-3p, hsa-miR-7855-5p, hsa-miR-4299, hsa-miR-6871-3p, hsa-miR-31-5p, hsa-miR-181a-5p, hsa-miR-450b-5p, hsa-miR-3615, hsa-miR-5696, hsa-miR-664b-3p, hsa-miR-579-3p, hsa-miR-664a-3p) appeared twice or more than twice in three predicting databases were selected for the further analysis. After that, we evaluated the prognostic values of 15 miRNAs in HCC using Kaplan-Meier plotter. The analytic results showed in Figure 4C-D indicated that high expression of 11 miRNAs including hsa-miR-2861, hsa-miR-5739, hsa-miR-4505, hsa-miR-6770-3p, hsa-miR-7855-5p, hsa-miR-4299, hsa-miR-6871-3p, hsa-miR-31-5p, hsa-miR-5696, hsa-miR-664b-3p, hsa-miR-664a-3p were found to be positively correlated with longer OS in HCC. On the contrary, upregulated the expression of hsa-miR-579-3p was found to be negatively associated with better OS in HCC. Additionally, no significant correlations between the expression values of hsa-miR-181a-5p, hsa-miR-450b-5p, hsa-miR-3615 and their prognostic values in HCC were found. Therefore, we chose hsa-miR-2861, hsa-miR-5739, hsa-miR-4505, hsa-miR-6770-3p, hsa-miR-7855-5p, hsa-miR-4299, hsa-miR-6871-3p, hsa-miR-31-5p, hsa-miR-5696, hsa-miR-664b-3p and hsa-miR-664a-3p for subsequent research. We particularly focused on miRNAs which were greatly related with HCC progression. As clinical parameters like histologic grade, pathologic stage, pathologic T status, pathologic N status, pathologic M status are indicators of tumor progression. Thus, we used the “Tumor Stage and Grade” analysis on OncomiR database to discover key miRNAs in HCC, and the results indicated that there were 0 clinical parameters in HCC associated with hsa-miR-2861, hsa-miR-5739, hsa-miR-4505, hsa-miR-6770-3p, hsa-miR-7855-5p, hsa-miR-4299, hsa-miR-6871-3p, hsa-miR-5696, hsa-miR-664b-3p (Figure 5A). Importantly, hsa-miR-31-5p was found to be closely related with histologic grade, pathologic stage, pathologic T status, pathologic N status, pathologic M status and sex clinical parameters in HCC and hsa-miR-664a-3p was significantly correlated with histologic grade, pathologic T status, pathologic N status and pathologic M status in HCC (Figure 5B-C). Then, we evaluated the expression values of hsa-miR-31-5p and hsa-miR-664a-3p in 10 none invasion-HCC tissues and 10 vascular invasion-HCC tissues (Figure 5D-E). We found that only hsa-miR-664a-3p was significantly downregulated in vascular invasion-HCC tissues compared with none invasion-HCC tissues, as expected. However, the expression of hsa-miR-31-5p was found to be significantly higher in vascular invasion-HCC than in none invasion-HCC tissues. It’s obvious that target gene negatively regulated by the miRNA, since overexpression the expression value of VCX3A was closely related with poor prognosis in HCC patients and VCX3A was importantly downregulated in none invasion-HCC tissues than in vascular invasion-HCC tissues, the upstream miRNA should downregulated in vascular invasion-HCC tissues than in none invasion-HCC tissues, like hsa-miR-664a-3p. Thus, hsa-miR-664a-3p serves as the most potential upstream miRNA binding to VCX3A.
Discovering TUBA3C as the most potential downstream target of VCX3A
In order to explore the mechanism, further analyses were performed to obtain downstream regulatory molecule of VCX3A. 94 correlated genes with correlation values ≥ 0.5 from cBioPortal database were chose as potential regulatory partners (Table 2). After that, starBase database was used to verify the correlations of those VCX3A-correlated genes pairs (Table 3). Only genes with correlation values also ≥ 0.5 in starBase were selected for the next research. 83 correlated genes were found have correlation values in starBase, while 11 correlated genes could not find correlation values. Among 83 correlated genes, we discovered 57 key correlated genes with correlation values more than 0.5 (Figure 6A). Next, we performed survival analyses of those 57 key genes through Kaplan-Meier plotter, the consequences indicated that only 21 genes were closely related with poor prognosis in HCC in accordance with VCX3A. The genes list as following: MAGEA6, MKRN3, LIN28B, CTAG2, DCAF8L1, MAGEA12, RFPL4B, DDX53, MAGEA3, GABRA3, SYT1, SSX1, CSMD1, CSAG1, FAM133A, C12ORF56, TUBA3C, GTSF1, MAGEB6, CLEC2L, ZNF257. However, 28 genes including VCX, VCX3B, NAA11, CARD18, RPL10L, DCAF4L2, DSCR4, MAGEB2, GNGT1, OR56A3, CNTNAP4, TGIF2LX, DCAF8L2, CT47B1, SLCO6A1, MAGEB1, SSX5, MAGEC1, MDGA2, OR8A1, XAGE5, NPFFR2, MAGEA11, DSCR8, MAGEA8, PAGE2, PAGE1 and GLB1L3 were found to be associated with better prognosis in HCC, not as expected. In addition, we found that there were no significant correlations between the expression values of COX7B2, MAGEC2, FSTL5, PAGE5 and prognosis in HCC. Moreover, 4 genes (XAGE1B, PPP4R3C, LINC01139, CT83) lose prognostic values information in Kaplan-Meier plotter (Figure 6B). Thus, 21 genes were selected for the further research. In the next step, correlation analysis of 21 key co-expressed genes in HCC patients with vascular invasion were performed through R software. As presented in Figure 6C, TUBA3C was found to be the most closely co-expression gene that interacted with VCX3A with r=0.66. Expression validations in TCGA and clinical samples demonstrated that TUBA3C was upregulated in tumor than in normal tissues, as well as in vascular invasion-HCC compared with none invasion-HCC tissues (Figure 6D-E). Altogether, based on all the analyses, VCX3A-TUBA3C was found to be the most reliable interaction network in HCC (Figure 7).
Table 2 : Co-expression genes of VCX3A in cBioPotral.
correlated gene
|
Spearman's Correlation
|
p-Value
|
q-Value
|
|
VCX
VCX3B
NAA11
XAGE1B
COX7B2
CARD18
RPL10L
DCAF4L2
MAGEA6
MKRN3
SSX4
LIN28B
CTAG2
DCAF8L1
CTAG1B
DSCR4
MAGEB2
MAGEC2
MAGEA12
RFPL4B
DDX53
PPP4R3C
MAGEA3
GABRA3
SYT1
SSX1
SSX3
GNGT1
OR56A3
SSX2
MAGEA2
CNTNAP4
GAGE4
TGIF2LX
CSMD1
DCAF8L2
CSAG1
FAM133A
SSX6P
LINC01139
BAGE
FSTL5
CT47B1
CDH9
SLCO6A1
RHOXF2B
LOC440173
MAGEB1
FLJ36000
SSX5
MAGEC1
C12ORF56
GAGE12J
GABRG2
TUBA3C
EZHIP
SLC44A5
MDGA2
TP53TG3B
GTSF1
MAGEB6
OR8A1
SOHLH2
XAGE5
NPFFR2
MAGEA11
DSCR8
CLEC2L
MAGEA8
PAGE2
HERC2P4
CSAG3
MUC15
KCNK9
ZNF257
PAGE5
CNGB3
ANKRD30BP2
NXF2
ZNF716
GAGE2D
PAGE1
GAGE12D
COL24A1
PHF2P1
CSAG2
GAGE1
CT83
ADAMTS20
NAP1L6
SSX8P
MAGEB16
HTR2C
GLB1L3
|
0.807
0.701
0.694
0.675
0.671
0.67
0.66
0.653
0.653
0.651
0.645
0.645
0.64
0.639
0.636
0.636
0.636
0.632
0.631
0.63
0.63
0.629
0.629
0.628
0.628
0.628
0.628
0.624
0.622
0.618
0.618
0.617
0.617
0.615
0.612
0.61
0.605
0.603
0.599
0.592
0.589
0.589
0.589
0.588
0.582
0.581
0.581
0.577
0.576
0.575
0.574
0.573
0.572
0.57
0.568
0.568
0.568
0.566
0.562
0.559
0.558
0.556
0.554
0.552
0.549
0.548
0.547
0.544
0.543
0.538
0.537
0.536
0.535
0.535
0.535
0.532
0.532
0.526
0.52
0.52
0.52
0.515
0.512
0.507
0.506
0.505
0.503
0.503
0.501
0.501
0.5
0.5
0.5
0.5
|
3.67E-81
8.80E-53
2.63E-51
1.26E-47
6.02E-47
8.97E-47
5.86E-45
9.57E-44
1.11E-43
2.94E-43
2.98E-42
2.99E-42
1.53E-41
2.21E-41
7.56E-41
8.34E-41
8.62E-41
3.70E-40
4.51E-40
5.97E-40
6.54E-40
1.04E-39
1.11E-39
1.26E-39
1.28E-39
1.50E-39
1.57E-39
6.27E-39
1.19E-38
4.66E-38
5.70E-38
5.95E-38
7.18E-38
1.54E-37
3.84E-37
7.47E-37
4.59E-36
7.66E-36
2.47E-35
2.66E-34
6.11E-34
6.92E-34
7.98E-34
9.78E-34
6.19E-33
7.87E-33
9.29E-33
2.87E-32
3.39E-32
5.72E-32
6.03E-32
8.88E-32
1.39E-31
2.22E-31
3.60E-31
3.68E-31
4.53E-31
8.30E-31
2.50E-30
4.72E-30
7.36E-30
1.15E-29
2.12E-29
3.75E-29
8.06E-29
1.08E-28
1.42E-28
3.17E-28
4.24E-28
1.58E-27
1.97E-27
2.64E-27
3.40E-27
3.56E-27
3.59E-27
7.38E-27
8.87E-27
3.65E-26
1.55E-25
1.57E-25
1.88E-25
5.21E-25
1.27E-24
3.58E-24
5.42E-24
6.35E-24
1.03E-23
1.15E-23
1.48E-23
1.66E-23
1.85E-23
2.06E-23
2.08E-23
2.25E-23
|
7.37E-77
8.83E-49
1.76E-47
6.35E-44
2.42E-43
3.00E-43
1.68E-41
2.40E-40
2.48E-40
5.91E-40
5.00E-39
5.00E-39
2.36E-38
3.17E-38
1.01E-37
1.02E-37
1.02E-37
4.13E-37
4.77E-37
6.00E-37
6.26E-37
9.51E-37
9.72E-37
1.03E-36
1.03E-36
1.16E-36
1.17E-36
4.50E-36
8.23E-36
3.12E-35
3.69E-35
3.73E-35
4.37E-35
9.07E-35
2.21E-34
4.17E-34
2.49E-33
4.05E-33
1.27E-32
1.34E-31
2.99E-31
3.31E-31
3.73E-31
4.46E-31
2.76E-30
3.44E-30
3.97E-30
1.20E-29
1.39E-29
2.30E-29
2.37E-29
3.43E-29
5.26E-29
8.25E-29
1.31E-28
1.32E-28
1.60E-28
2.88E-28
8.53E-28
1.58E-27
2.42E-27
3.73E-27
6.77E-27
1.18E-26
2.49E-26
3.30E-26
4.27E-26
9.36E-26
1.23E-25
4.54E-25
5.56E-25
7.36E-25
9.35E-25
9.61E-25
9.61E-25
1.95E-24
2.31E-24
9.40E-24
3.94E-23
3.94E-23
4.66E-23
1.28E-22
3.07E-22
8.55E-22
1.28E-21
1.48E-21
2.37E-21
2.61E-21
3.34E-21
3.70E-21
4.08E-21
4.50E-21
4.50E-21
4.81E-21
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table 3: Co-expression analysis of VCX3A in starBase. (NA=Not Applicable)
VCX3A co-expression gene
|
R
|
P
|
VCX
VCX3B
NAA11
XAGE1B
COX7B2
CARD18
RPL10L
DCAF4L2
MAGEA6
MKRN3
SSX4
LIN28B
CTAG2
DCAF8L1
CTAG1B
DSCR4
MAGEB2
MAGEC2
MAGEA12
RFPL4B
DDX53
PPP4R3C
MAGEA3
GABRA3
SYT1
SSX1
SSX3
GNGT1
OR56A3
SSX2
MAGEA2
CNTNAP4
GAGE4
TGIF2LX
CSMD1
DCAF8L2
CSAG1
FAM133A
SSX6P
LINC01139
BAGE
FSTL5
CT47B1
CDH9
SLCO6A1
RHOXF2B
LOC440173
MAGEB1
FLJ36000
SSX5
MAGEC1
C12ORF56
GAGE12J
GABRG2
TUBA3C
EZHIP
SLC44A5
MDGA2
TP53TG3B
GTSF1
MAGEB6
OR8A1
SOHLH2
XAGE5
NPFFR2
MAGEA11
DSCR8
CLEC2L
MAGEA8
PAGE2
HERC2P4
CSAG3
MUC15
KCNK9
ZNF257
PAGE5
CNGB3
ANKRD30BP2
NXF2
ZNF716
GAGE2D
PAGE1
GAGE12D
COL24A1
PHF2P1
CSAG2
GAGE1
CT83
ADAMTS20
NAP1L6
SSX8P
MAGEB16
HTR2C
GLB1L3
|
r=0.771
r=0.813
r=0.632
r=0.615
r=0.612
r=0.606
r=0.631
r=0.568
r=0.637
r=0.504
r=0.383
r=0.623
r=0.577
r=0.561
r=0.224
r=0.714
r=0.626
r=0.589
r=0.622
r=0.622
r=0.534
r=0.558
r=0.620
r=0.635
r=0.518
r=0.586
r=0.480
r=0.625
r=0.539
r=0.481
r=0.447
r=0.575
NA
r=0.596
r=0.581
r=0.535
r=0.604
r=0.531
NA
r=0.606
NA
r=0.546
r=0.513
r=0.497
r=0.573
r=0.487
NA
r=0.565
NA
r=0.545
r=0.548
r=0.608
r=0.308
r=0.445
r=0.687
NA
r=0.467
r=0.540
r=0.000
r=0.655
r=0.513
r=0.570
r=0.487
r=0.593
r=0.622
r=0.536
r=0.664
r=0.559
r=0.672
r=0.598
r=0.437
NA
r=0.490
r=0.487
r=0.513
r=0.560
r=0.497
r=0.386
r=0.225
r=0.448
NA
r=0.560
r=0.000
r=0.479
NA
NA
r=0.461
r=0.522
r=0.474
r=0.485
NA
r=0.467
r=0.449
r=0.505
|
p=8.44e-75
p=2.91e-89
p=3.72e-43
p=2.90e-40
p=8.01e-40
p=8.52e-39
p=6.29e-43
p=2.38e-33
p=6.97e-44
p=1.59e-25
p=1.65e-14
p=1.31e-41
p=1.21e-34
p=1.95e-32
p=1.17e-05
p=1.69e-59
p=3.85e-42
p=2.71e-36
p=2.04e-41
p=2.29e-41
p=5.41e-29
p=5.74e-32
p=4.31e-41
p=1.56e-43
p=4.27e-27
p=6.63e-36
p=5.60e-23
p=6.56e-42
p=1.34e-29
p=5.31e-23
p=9.43e-20
p=2.91e-34
NA
p=2.29e-37
p=4.16e-35
p=4.48e-29
p=1.51e-38
p=1.24e-28
NA
p=7.88e-39
NA
p=1.71e-30
p=1.88e-26
p=9.66e-25
p=4.89e-34
p=1.22e-23
NA
p=5.90e-33
NA
p=2.77e-30
p=1.09e-30
p=3.21e-39
p=1.19e-09
p=1.36e-19
p=1.56e-53
NA
p=1.13e-21
p=1.10e-29
p=1.00e+00
p=4.18e-47
p=1.69e-26
p=1.40e-33
p=1.11e-23
p=5.97e-37
p=2.39e-41
p=3.68e-29
p=6.34e-39
p=4.56e-32
p=1.81e-50
p=1.19e-37
p=6.81e-19
NA
p=5.11e-24
p=1.02e-23
p=1.81e-26
p=2.92e-32
p=1.01e-24
p=9.19e-15
p=1.08e-05
p=7.87e-20
NA
p=2.59e-32
p=1.00e+00
p=7.67e-23
NA
NA
p=4.90e-21
p=1.58e-27
p=2.49e-22
p=2.06e-23
NA
p=1.23e-21
p=6.47e-20
p=1.26e-25
|