Identification of DEGs in Gastric cancer disease
In our current study, there were 348 GC tissues and 141 healthy tissues. With the help of GEO2R online tools, we obtained 5599, 2755, and 2473 DEGs from the three datebases: GSE13911, GSE66229, and GSE79973, respectively. Among the three datasets, the common DEGs were identified via Venn diagram software. The findings revealed that althogether 251 common DEGs were explored, containing 187 and 64 genes which controlling down and up related genes in the Gastric cancer tissues (Table 1 & Fig. 2).
Table 1
All 251 commonly differentially expressed genes (DEGs) were detected from three profile datasets, including 187 down-regulated genes and 64 up-regulated genes in the Gastric cancer tissues and normal gastric tissues.
DEGs
|
Genes Name
|
up-regulated
|
IGF2BP3 CCNB1 LOC100129518///SOD2 COL1A1 BIRC5 ADAMTS2 KLHL7 KIF14 MAD2L1 BICD1 SPP1 FAM72A///FAM72D///FAM72B///FAM72C NDC80 CCNA2 NUF2 UBE2T TEAD4 ECT2 CDH3 MTFR2 PRC1 LRP8 CEP55 CEMIP DDIAS S100A2 WISP1 AJUBA CLDN1 APOC1 NEK2 ESM1 PLAU DEPDC1B HMGB3 CXCL8 IL13RA2 HOXA10 KIF2C CDCA7 BUB1 TRIP13 DUXAP10 LOC101928195///LOC100996643///MTHFD1L TMEM158 ASPM INHBA ATAD2 KNL1 STIL UBE2C ULBP2 TOP2A WDR72 DTL MEST KIF20A COL10A1
PMEPA1 HOXC6 CTHRC1 CDKN3 LINC01296///DUXAP10 CENPF
|
down-regulated
|
BTG2 ATP5F1 PDE1C MAOA ZNF385B PWP2 ALAD ACADL PIR-FIGF///FIGF ZBTB20 HDHD2 NTN4 SERP1
SYNJ2BP-COX16///SYNJ2BP PPID SCNN1B KLHDC2 ADCYAP1R1 UBE2QL1 FAM13A ADHFE1 SLC25A4 LOC100506870///LOC283140 MYOC GIF SYNE1 GNG7 VSTM2A ZSCAN31 PRDM5 EFCC1 STAM2 TLE4 SH3GL2
CKMT2 BBIP1 KCNJ16 SLC26A7 ADAMTSL1 KIAA2022 PCBP1-AS1 FAHD2CP SLC16A7 FMO4 PGRMC2 ATP4 ACD36 FGD4 MAL AQP4 ESRRG LYRM5 CPA2 ABCA8 EFCAB14 DBT SLC1A2 TPCN2 TCEB3 USP53 ARRDC4 TMEM100 CREBL2 SPINK2 CNTN3 PRDM11 ETNPPL RGS5 LOC101927263 PACRG RCCD1 UBL3 CYB5R1 LINC01105 ADGRL3 ATP4B TMEM116 SMIM14 6-Mar ZNF626 LOC728730 ENPP6 CIRBP ECHDC2 GPX3 KCNMB2 THSD4 HDC MTERF2 SAR1B TRIM50 FAM214A MITF TRIM74///TRIM73 RNF14 CLTA IGH KL BDH2 APOBEC2 DGKD RPS6KA6 MFSD4A ALDH6A1 PHYKPL NEDD4L PDGFD KIT GCNT2 MIR29C///MIR29B2 SIK2 DMXL1 CWH43 PGA4///PGA3///PGA5 PDK4 GFRA2 TRIP11 HACD1 GPR155 NR3C2 MUT UMAD1 OPCML LOC100505501 PLIN5 RNASE1 MYZAP SMIM5 PLPP3 ACACB GRIA4 BAALC RPRM CYFIP2 FBXL13 SPC24 YIF1B RGMB SMDT1 FBP2 FAM150B CADM2 LINC00849///SLC25A16 MAGI3 CHGA WIPF3 TOM1L2 VAPA RAB11B-AS1 ADH7 ASPA PDILT C14orf159 TXNL1 LINC00982 CCKBR ADRB2 GRIA3 NTRK3 SLC7A8 SCARA5 ACADSB CPEB2 SLC2A12 LIFR STX12 FNDC5 PCAT18 HADH 2-Mar GSTA3 SIDT2 CHIA ZEB2 METTL7A KCNE2 RAB27A TAPT1 LOC101926959 SIGLEC11 LOC101929219///C1orf186 DNER GAB1 C21orf58 KAT6B DYX1C1-CCPG1///CCPG1
|
Identification and function of DEGs in GC
Associated with GO terms, the genes of up-regulated and down-regulated DEGs were enriched in the cell division, mitotic nuclear division, and mast cell cytokine production. The markly up-regulated and down-regulated DEGs in biological process (BP) was cell division, mitotic nuclear division, and mast cell cytokine production. In addition to the enrichment in mitotic metaphase plate congression, the up-regulated DEGs were significantly enriched in the BPs of cell division. In contrast, the down-regulated DEGs are significantly enriched in the metabolic process.
Gene ontology and pathway enrichment analysis
We performed functional and pathway enrichment analyses to investigate the biological classification of DEGs via DAVID. There were three categories in GO analysis: Biological process (BP), cellular component (CC), and molecular function (MF) GO. In biological processes-associated category showed by GO pathway enrichment analysis, the genes were significantly involved in nuclear chromosome segregation, sister chromatid segregation, cell division, cell cycle process, mitotic cell cycle process and down-regulated DEGs in organic acid catabolic process, carboxylic acid catabolic process, small molecule catabolic process, lipid modification, fatty acid catabolic process, fatty acid oxidation (Table 2). Molecular function (MF) of DEGs were significantly enriched in identical protein binding, microtubule binding, enzyme binding, tubulin binding, cytoskeletal protein binding protein kinase binding, cofactor binding, coenzyme binding, potassium channel regulator activity, ligand-gated ion channel activity, ligand-gated channel activity (Table 2).Changes in the cell components (CCs) of DEGs were mainly enriched in the condensed chromosome kinetochore, condensed chromosome, centromeric region kinetochore, condensed chromosome, chromosome, centromeric region, midbody (Table 2& Fig. 3).
Table 2
Gene ontology analysis of differentially expressed genes in GC
Expression
|
Category
|
Term
|
Count
|
%
|
p-Value
|
FDR
|
Up-
regulated
Down-
regulated
|
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_BP_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_CC_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
GOTERM_MF_DIRECT
|
GO:0051301 ~ cell division
GO:0007067 ~ mitotic nuclear division
GO:0007062 ~ sister chromatid cohesion
GO:0007059 ~ chromosome segregation
GO:0007080 ~ mitotic metaphase plate congression
GO:0000910 ~ cytokinesis
GO:0030496 ~ midbody
GO:0000777 ~ condensed chromosome kinetochore
GO:0000776 ~ kinetochore
GO:0000775 ~ chromosome, centromeric region
GO:0000942 ~ condensed nuclear chromosome outer kinetochore
GO:0000922 ~ spindle pole
GO:0042802 ~ identical protein binding
GO:0005515 ~ protein binding
GO:0016887 ~ ATPase activity
GO:0004842 ~ ubiquitin-protein transferase activity
GO:0003777 ~ microtubule motor activity
GO:0034220 ~ ion transmembrane transport
GO:0006635 ~ fatty acid beta-oxidation
GO:0009083 ~ branched-chain amino acid catabolic process
GO:0030318 ~ melanocyte differentiation
GO:0008152 ~ metabolic process
GO:0032762 ~ mast cell cytokine production
GO:0005759 ~ mitochondrial matrix
GO:0005739 ~ mitochondrion
GO:0005887 ~ integral component of plasma membrane
GO:0043235 ~ receptor complex
GO:0005886 ~ plasma membrane
GO:0070062 ~ extracellular exosome
GO:0015459 ~ potassium channel regulator activity
GO:0005496 ~ steroid binding
GO:0008900 ~ hydrogen:potassium-exchanging ATPase activity
GO:0000062 ~ fatty-acyl-CoA binding
GO:0004971 ~ AMPA glutamate receptor activity
|
14
11
8
5
4
4
9
8
6
5
3
5
10
41
4
5
3
8
4
3
3
6
2
12
22
22
5
47
34
4
3
2
3
4
|
14.2
11.16
8.1
5
4
4
9.13
8.12
6.09
5.07
3.04
5.07
10.15
41.60
4.06
5.07
3.04
3.04
1.52
1.14
1.14
2.28
0.76
4.56
8.36
8.36
1.9
17.9
12.9
0.47
2.17
2.52
2.65
3
|
1.2E-10
9.7E-09
5.5E-08
8.3E-05
2.7E-04
5.8 E-04
6.26E-09
9.6 E-09
5.35E-06
3.00E-05
5.74E-05
3.75E-05
6.46E-04
0.00139
0.02218
0,02801
0.03028
0.00243
0.00657
0.01165
0.01287
0.01574
0.01731
1.14E-04
0.00442
0.00873
0.02325
0.02444
0.03132
0.004676
0.021778
0.0252
0.026548
0.033459
|
1.74 E-07
1.4 E-05
7.93 E-05
0.11983
0.38443
0.831662
7.16 E-06
1.10E-05
0.00612
0.034353
0.065715
0.428069
0.747165
1.596840
22.56086
22.92955
28.10169
3.70122
9.731282
16.64097
18.2266
21.83896
23.7548
0.139087
5.251997
10.12515
24.90296
26.00801
32.1178
6.175478
25.87697
29.32705
30.6453
37.04963
|
Table 3
Pathway Enrichment Analysis of Common Genes Function in Gastric Cancer
Pathway ID
|
Name
|
Count
|
%
|
p-valve
|
Genes
|
hsa04914
|
Progesterone-mediated oocyte maturation
|
4
|
6.67
|
0.001636
|
CCNB1, MAD2L1, BUB1, CCNA2
|
hsa04110
hsa04114
hsa05161
hsa04390
hsa05202
|
Cell cycle
Oocyte meiosis
Hepatitis B
Hippo signaling pathway
Transcriptional misregulation in cancer
|
4
3
3
3
3
|
6.67
5
5
5
5
|
0.0044859
0.0369046
0.0597128
0.0641468
0.0765009
|
CCNB1, MAD2L1, BUB1, CCNA2
CCNB1, MAD2L1, BUB1
CCNA2, CXCL8, BIRC5
TEAD4, BIRC5, AJUBA
HOXA10, CXCL8, PLAU
|
PPI network and modular analysis
Totally, containing 193 nodes and 633 edges, 251 DEGs were imported into the DEGs PPI network complex, and 187 down-regulated and 64 up-regulated genes were included (Fig. 4a). The 187 down-regulated DEGs were not contained in the DEGs PPI network (Fig. 4a). Then we made use of Cytotype MCODE to gain further results: The outcomes showed that among the 64 nodes there were 26 central nodes of up-regulated genes (Fig. 4b).
KM plotter and GEPIA datebase analysis
We identified the survival data of 26 core genes via Kaplan Meier plotter(http://kmplot.com/analysis/). Among these genes, 24 genes showed a significant worse survival, while 2 had no significant (P < 0.05, Table 4 & Fig. 5, Fig. S1). Then, between cancerous and normal genes, GEPIA was used to dig up the 24 gene expression level. Contrasted to normal stomach samples, results revealed that 22 of 24 genes reflected highly enriched in GC samples. (P < 0.05, Table 5 & Fig. 5, Fig. S2)
Table 4
The prognostic information of the 26 key candidate genes
Category
|
Genes
|
Genes with significantly
worse survival (P < 0.05)
|
ASPM ATAD2 BIRC5 BUB1 CASC5 CCNA2 CCNB1 CDKN3 CENPF CEP55DEPDC1B DTL ECT2KIF14 MAD2L1 NDC80 NEK2 NUF2 PRC1 STILTOP2A TRIP13 UBE2C UBE2T
|
Genes with significantly
worse survival (P > 0.05)
|
RAB6KIFL KIF2C
|
Table 5
Vadidation of 22 genes via GEPIA
Category
|
Genes
|
Genes with high expressed
in GC (P < 0.05)
|
ASPM ATAD2 BIRC5 BUB1 CASC5 CCNA2 CCNB1 CDKN3 CENPF CEP55DEPDC1B DTL ECT2KIF14 MAD2L1 NDC80 NEK2 NUF2 PRC1 STILTOP2A TRIP13 UBE2C UBE2T
|
Genes without high expressed in OC (P > 0.05)
|
RAB6KIFL KIF2C
|
KEGG pathway enrichment of Re-analysis of 22 selected genes
To better understand these 22 selected DEGs' possible pathway, we re-analyzed KEGG pathway enrichment via DAVID (P < 0.05). We found that five core genes (BUB1, MAD2L1, CCNA2, CCNB1, and BIRC5) markedly enriched in the progesterone-mediated oocyte maturation and cell cycle pathway (P = 1.9E-3, Table 6). Among all these genes, the overexpression of BIRC5, TRIP13 and UBE2C was negative correlated with the poor out comes of gastric cancer patients, which was further investigated.
Upregulation of BIRC5, TRIP13 and UBE2C in gastric cancer tissues from clinical patients and are related to cell proliferation
To validate the expression level of these potential genes in cancer tissues, we collected 15 pairs of tumor tissues and adjacent normal tissues of gastric cancer. With RT-PCR assay, we found that BIRC5, TRIP13 and UBE2C were significantly upregulated in tumor tissues (Fig. 6A, B, C), these data showed that these genes may be applied as biomarkers for gastric cancer. To investigate whether these genes exert key functions in cancer, we transfected specific shRNAs into gastric cancer cells. Through CCK-8 assay, we observed that cell proliferation was significantly suppressed in BIRC5, TRIP13 or UBE2C knockdown cells, respectively (Fig. 6D, E, F).
Knockdown of BIRC5, TRIP13 or UBE2C reduced cisplatin resistance
Cisplatin is one of the most frequent drugs currently used for treating gastric cancer. However, cisplatin resistance is a big obstacle for successfully therapy. We ought to investigate whether these critical genes are related to cisplatin resistance. Then cells with knockdown of each specific gene were treated with cisplatin. Then cell survival fraction and apoptosis were examined. Our data showed that knockdown of BIRC5, TRIP13 or UBE2C significantly inhibited the cell survival fraction after cisplatin treatments (Fig. 7A, B, C). Knockdown of these genes also significantly increased cisplatin-induced cell apoptosis (Fig. 7D, E, F). These data suggested that the high regulation of BIRC5, TRIP13 or UBE2C genes are closely related to cell proliferation as well as cisplatin resistace, which could be used as potential target for treating gastric cancers.