Identity of ImTRDG and functional enrichment results
The two datasets GSE135222 and GSE126044 in the CTR-DB database are about NSCLC patients who received immunochemotherapy, with a total of 43 patients. According to the effect of immunotherapy, they were divided into 13 responders (CR and PR) and 30 non-responders (SD and PD), as shown in Table 1. Through differential analysis and the set threshold, a total of 176 differential genes were screened, of which 72 were up-regulated genes and 104 genes were down-regulated. Figures 2A and Figs. 2B showed the volcano map and heat map of differential genes.
Table 1
Overview of receiving immunotherapy dataset information. complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD).
Treatment response
|
Number
|
Data sets
|
Medication regimen
|
Pathological type
|
non-responder (SD and PD)
|
19
|
GEO:GSE135222
|
Immunotherapy
|
Lung non-small cell carcinoma
|
responder (CR and PR)
|
8
|
GEO:GSE135222
|
anti-PD-1/PD-L1
|
Lung non-small cell carcinoma
|
non-responder (SD and PD)
|
6
|
GEO:GSE126044
|
Nivolumab
|
Lung squamous cell carcinoma
|
non-responder (SD and PD)
|
5
|
GEO:GSE126044
|
Nivolumab
|
LUAD
|
responder (CR and PR)
|
3
|
GEO:GSE126044
|
Nivolumab
|
Lung squamous cell carcinoma
|
responder (CR and PR)
|
2
|
GEO:GSE126044
|
Nivolumab
|
LUAD
|
Through metascape enrichment analysis, the top 20 significant results were extracted, suggesting that most of the differential genes are involved in immune-related pathways (Fig. 3A), through the MOCODE algorithm, we obtained three densely connected PPI (protein-protein interaction) MCODE components, which are involved in neutrophil degranulation, regulation of natural killer cell mediated cytotoxicity and CD8 TCR (T cell receptor) pathway, respectively, as shown in Fig. 3B.
Target genes for model screening and immune infiltration nalysis
After obtaining 176 ImTRDGs, univariate cox regression analysis was performed, and a total of 4 genes (CLEC4E, HOXC8, MMP12 and NFE2) were obtained that were associated with the prognosis of T1N0M0 LUAD as shown in Fig. 4A-D. Through multivariate cox and step functions, the risk model (Riskscore= -1.0068*NFE2 + 0.2741*MMP12 + 0.5986*HOXC8) constructed by 3 genes (HOXC8, MMP12 and NFE2), 81 samples can be divided into high and low groups according to riskscore, survival analysis showed that the survival difference between the high-risk group and the low-risk group was statistically significant (HR = 3.491, 95%CI: 1.062–11.475, P = 0.0395). The 1-year, 3-year and 5-year ROC curve area was 0.916, 0.90 and 86.3, respectively (Fig. 5A-D). The GSE50081 data was used to verify the accuracy of the model. The results showed that the survival prognosis of patients in the high and low risk groups was statistically different (p = 0.048) (Fig. 6A), and the 5-year ROC curve area was 0.67(Fig. 6B), which was relatively stable. Combined with clinical data (age, gender and smoking status), univariate and multivariate cox regression analysis was performed, it has showed that MMP12, NFE2 and HOXC8 can be used as independent prognostic factors for T1N0M0 LUAD (Supplementary Fig. 1A-B). The correlation analysis between riskscore and immune infiltration scores showed that there was a good positive correlation between riskscore and cytotoxicity, NK.cell and CD8T cell scores (Fig. 6C).
Differential expression and multi-type prognostic analysis
The differential expression of the three genes in LUAD and normal samples from GTEx database was analyzed, and the results showed that MMP12 and HOXC8 were highly expressed in LUAD samples, while NFE2 was low expressed in LUAD samples (Supplementary Fig. 2A-C). The immunohistochemical information of NFE2 in LUAD and normal samples was searched by HPA, using HPA001914 antibody labeling, the results indicated that NFE2 was moderately stained in normal alveolar tissue, but low in LUAD. Using HPA028911 antibody labeling, it was found that HOXC8 was not stained in normal alveolar tissue, but moderately stained in alveolar macrophages, and HOXC8 was moderately stained in LUAD tumor tissue. The results of immunohistochemistry and mRNA expression were consistent. (Fig. 7A-D) Survival analysis showed that FOXC8 high expression was significantly correlated with poor OS, PFS, DSS, and DF of LUAD (Fig. 8A-D).
Gene expression and pathway activity result
GSCA–Expression and pathway activity module estimated difference of three genes expression between pathway activity groups (activation and inhibition). The results showed that NFE2 may have inhibitory effects on the Apoptosis, CellCycle, EMT and Hormone AR pathways of LUAD, while it has an activation effect on the MAPK and mTOR pathways. MMP12 has an activating effect on Apoptosis, CellCycle and EMT pathways of LUAD, and has an inhibitory effect on MAPK pathway, and HOXC8 has an activating effect on CellCycle pathway (Fig. 9A). Through pathway ssGSEA analysis, the relationship between target genes and pathway scores was calculated and found that MMP12 had positive correlation with Cellular_response_to_hypoxia, Tumor_proliferation_signature, G2M_checkpoint, Tumor_Inflammation_Signature and DNA_repair. NFE2 has negative correlation with Tumor_proliferation_signature and G2M_checkpoint, and HOXC8 has positive correlation with Tumor_proliferation_signature and G2M_checkpoint (Fig. 9B).
Copy Number Variation (CNV) and methylation survival prognostic analysis of target genes
The summary of CNV of target genes in LUAD shown in the Table 2. The results of the CNV and LUAD survival prognostic analysis showed that compared with the WT group, the HOXC8 and NFE2 CNV groups were associated with poor OS (Fig. 10A-B), and NFE2 CNV groups were also associated with poor PFS in LUAD (Fig. 10C). The MMP12 CNV was associated with poor DFI (Fig. 10D). The results of CNV and survival prognostic analysis after the integration of the three genes showed that the gene set CNV was associated with poor OS in LUAD(Fig. 10E). Survival analysis showed that MMP12 hypermethylation levels were associated with good DFS, DSS and DFI (Fig. 9F-H), and HOXC8 hypermethylation levels were associated with poor PFS and DFI in LUAD (Fig. 10I-J).
Table 2
The summary of CNV of target genes in LUAD. Total amp.(%): the percentage of samples with copy number amplification, including heterozygous and homozygous amplification; Total dele.(%): the percentage of samples with copy number deletion, including heterozygous and homozygous deletion;
Symbol
|
Total amp.(%)
|
Total dele.(%)
|
Hete amp.(%)
|
Hete dele.(%)
|
Homo amp.(%)
|
Homo dele.(%)
|
HOXC8
|
28.68217
|
18.21705
|
27.51938
|
18.02326
|
1.162791
|
0.193798
|
MMP12
|
26.16279
|
19.37985
|
24.22481
|
18.99225
|
1.937985
|
0.387597
|
NFE2
|
28.48837
|
18.60465
|
27.32558
|
18.41085
|
1.162791
|
0.193798
|
Hete amp.(%): the percentage of samples with copy number heterozygous amplification; Hete dele.(%): the percentage of samples with copy number heterozygous deletion; Homo amp.(%): the percentage of samples with copy number homozygous amplification; Homo dele.(%): the percentage of samples with copy number homozygous deletion. |
Drug Sensitivity Analysis
From the GDSC database, we analyzed that NFE2 mRNA expression was correlated with IC50 of Nilotinib, TL-1-85 and BHG712, and MMP12 mRNA expression was negatively correlated with Gefitinib IC50(Fig. 11A); CTRP database analysis found that NFE2 mRNA expression was negatively correlated with BRD-K01737880 IC50, HOXC8 mRNA expression was positively correlated with tacedinaline, JQ-1 IC50 (Fig. 11B); CCLE database results indicated that the FGFR targeting drug TKI258 IC50 difference was statistically significant in the HOXC8 mRNA high and low expression groups, In the MMP12 mRNA high and low expression groups, the IC50 differences of c-MET targeting drug PF2341066, ALK targeting drug TAE684 and IGF1R targeting drug AEW541 were statistically significant (Supplementary Fig. 3A-B).
Immune infiltration analysis
Gene expression and immune infiltration analysis showed that MMP12 was correlated with many immune infiltration components, among which it was positively correlated with nTreg, iTreg and Exhausted, and negatively correlated with Th17 and Th2. NFE2 expression was negatively correlated with central_memory, HOXC8 expression was positively correlated with nTreg, and negatively correlated with Gamma_delta and MAIT (Mucosal Associated Invariant T) (Fig. 12A).
The results of gene CNV and immune infiltration showed that NFE2 and HOXC8 CNV were positively correlated with nTreg and negatively correlated with CD4_T and Th2(Fig. 12B).
The results of gene methylation and immune infiltration analysis showed that MMP12 methylation was negatively correlated with ntreg cells and positively correlated with CD_4T cells, NFE2 methylation was positively correlated with Th17, and negatively correlated with NK cells, Th1 cells, Cytotoxic and Exhausted cells, and HOXC8 methylation was positively correlated with DCs. cells, CD_4T cells were positively correlated (Fig. 12C).
After integrating the CNV results of the three genes, their relationship with immune infiltration was analyzed, and it was found that nTreg, exhausted, effector_memory, monocyte, neutrophil, Th1 cells aggregated in high CNV tumors, while CD4_naive, Th2, Tfh, NKT (Natural killer T cell), Gamma_delta, NK, MAIT and CD4_T aggregated in low CNV tumors (Fig. 12D).
Expression Relationship and network between target genes and immune checkpoint genes
The correlation analysis of the three genes and immune checkpoint genes found that only MMP12 had a weak linear correlation with immune checkpoint genes (Fig. 13A). The target genes were divided into high and low expression groups according to their expression levels. Between the high and low expression groups of HOXC8, the expressions of CD274 and HAVCR2 were significantly different (Fig. 13B). The expressions of HAVCR2, PDCD1LG2, CTLA4, TIGIT, LAG3 and PDCD1 were all different in the NFE2 high and low expression groups (Fig. 13C). In the high and low expression groups of MMP12, the expressions of SIGLEC15, TIGIT, CD274, HAVCR2, PDCD1, CTLA4, LAG3 and PDCD1LG2 were statistically different (Fig. 13D). Through the GenCLiP 3 website to analyze the potential regulatory networks of risk target genes and immune check genes, some of them have been confirmed by experiments, and some regulatory networks still need to be verified in the experimental area, as shown in the Fig. 14.
Analysis of target gene and immune efficacy
The TIDE algorithm was used to calculate the response of the high and low expression LUAD of the three target genes to immunotherapy (Table 3). The results showed that 110 patients in the NFE2 high expression group responded to immunotherapy, 147 patients did not respond to immunotherapy, 87 patients in the NFE2 low expression group responded to immunotherapy, and 169 patients did not respond to immunotherapy. The TIDE score results showed that the TIDE score of the NFE2 low expression group was higher, indicating that the effect of immunotherapy was poor, indicating that the high expression of NFE2 may be a positive indicator of immunotherapy (Fig. 15A). This is consistent with the CTR-DB immunotherapy response differential gene results (Fig. 15B).
Table 3
Statistical table of immune responses of samples in different groups in prediction results.
Response
|
NFE2
|
HOXC8
|
MMP12
|
high
|
low
|
high
|
low
|
high
|
low
|
True
|
110
|
87
|
85
|
112
|
119
|
78
|
False
|
147
|
169
|
172
|
144
|
137
|
179
|
In the HOXC8 high expression group, 85 patients responded to immunotherapy, 172 patients did not respond to immunotherapy, 112 patients in the HOXC8 low expression group responded to immunotherapy, and 144 patients did not respond to immunotherapy. The TIDE score results showed that the TIDE score was higher in the high HOXC8 expression group, indicating that the immunotherapy effect was poor, which means that the high expression of HOXC8 may be a negative indicator of immunotherapy (Fig. 15C), which is consistent with the CTR-DB immunotherapy response differential gene results (Fig. 15D).
In the MMP12 high expression group, 119 patients responded to immunotherapy, 137patients did not respond to immunotherapy, 78 patients in the MMP12 low expression group responded to immunotherapy, and 179 patients did not respond to immunotherapy. The TIDE score results showed that the TIDE score of the MMP12 low expression group was higher, indicating that the effect of immunotherapy was poor, indicating that the high expression of MMP12 may be a positive indicator of immunotherapy (Fig. 15E). This is consistent with the CTR-DB immunotherapy response differential gene results (Fig. 15F).