While lung cancer is still the leading cause of cancer-related deaths globally, Non–small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for a large proportion of all lung cancer cases [34, 35]. Therefore, choosing the appropriate medicine integrated with standard oncologic care is particularly important for NSCLC patients. Traditional Chinese medicine is an ancient popular medicine that originated and developed in China. Since it has several unique attributes like the presence of multiple active substances, multiple key targets as well as low toxicity , it also possesses superior anti-tumor properties that can be applied in treating different tumors . Our study determined the key active ingredients and possible detailed molecular mechanisms of DBD in the NSCLC treatment through bioinformatics technology to further improve the desired treatment effects as well as to prolong the survival rate of NSCLC patients. In this study, the active ingredients and related targets of DBD were screened from the TCMSP database and further analyzed by GeneCards and OMIM databases to screen out the potential targets for NSCLC. Additionally, the intersection of both DBD ingredients-related targets and the NSCLC related targets was employed to obtain the core targets. Subsequently, a PPI network and a drug-ingredient-target-disease network were constructed through core targets while using R software later to perform GO function and KEGG pathway enrichment analysis. The top five active DBD ingredients involved in degree analysis were quercetin, kaempferol, formononetin, isorhamnetin, and hederagenin, while the top ten main core targets included HSP90AA1, NCOA2, PPARG, PRKACA, NOS2, PDE3A, PTGS1, PTGS2, ADRB2, and ESR1. Subsequently, the analysis of five main active ingredients with ten core targets by molecular docking process discovered that the combination of quercetin and PTGS1 had the best binding affinity. Additionally, the analysis of ten main target genes survival and the NSCLC prognosis through the TCGA database proved that due to the major distribution of PDE3A in the LU65 and NCI-H810 NSCLC tumor cell lines, it has a statistical significance for the prognostic survival time of NSCLC patients,
According to the drug-ingredient-target-disease network, it was observed that DBD has five main active ingredients: quercetin, kaempferol, formononetin, isorhamnetin, and hederagenin. Since quercetin, a bioflavonoid, can induce Hsp70 inhibition involved in growth inhibition of lung cancer cells, it has a great potential as a chemosensitizer in lung cancer treatment as well as the incorporation of dietary quercetin can also be a promising option for cancer prevention [38, 39]. Kuo et al., in their study, verified that kaempferol could be used as a radiosensitizer for NSCLC in vitro and in vivo while significantly improving the lethality of tumor cells . Formononetin is a novel herbal isoflavonoid, which when isolated from herbal medicine might act as a potential chemopreventive drug for lung cancer therapy through induction of cell cycle arrest and apoptosis in NSCLC cells . Isorhamnetin, a traditional Chinese medicine used to treat angina pectoris and acute myocardial infarction, displays a series of anti-tumor activities . Past literary insights on A549 lung cancer cells discovered that isorhamnetin at a concentration of 20 µg/mL can induce apoptosis in A549 cells, upregulates the expression of apoptotic genes Bax, Caspase-3, and p53, as well as down-regulates the expression of Bcl-2, cyclin D1, and PCNA proteins. Isorhamnetin’s mechanism of action may involve apoptosis initiation induced by down-regulation of oncogenes and up-regulation of apoptotic genes, thus proving that it can significantly inhibit the growth of A549 cells by inducing cell apoptosis . Hederagenin, an oleanolic acid derivative isolated from ivy leaves by displaying potential anti-tumor activity, might become a promising therapeutic candidate for human colon cancer . A study by Wang et al. reckoned that hederagenin can also induce ROS accumulation and enhance cisplatin and paclitaxel cytotoxicity in lung cancer cells by blocking autophagic flux . Therefore, hederagenin also has a potential synergistic effect in the treatment of lung cancer.
After exploring 5,773 candidate NSCLC targets from GeneCards and OMIM databases, 140 common targets were obtained between the NSCLC and DBD, which were subsequently considered as potential targets for the NSCLC treatment. Through the visual analysis of the drug-ingredient-target-disease network and degree ranking, ten core genes were identified. The degree of association between these genes is shown in Figure 6. These ten core genes included HSP90AA1, NCOA2, PPARG, PRKACA, NOS2, PDE3A, PTGS1, PTGS2, ADRB2, and ESR1and may play an important role in tumor cells, particularly in the process of proliferation, migration, and apoptosis. A previous study disclosed that upregulated KCNQ1OT1 levels in NSCLC tissues and cell lines affirmed that higher KCNQ1OT1 levels were related to the poor progression-free survival of NSCLC patients . Additionally, it was found that the HSP90AA1 expression was reduced after downregulating KCNQ1OT1 levels, which proved that KCNQ1OT1 positively regulated the expression of HSP90AA1 by the formation of the miR-27b-3p sponge. These data revealed the role of KCNQ1OT1 as an oncogene through the modulation of the miR-27b-3p/HSP90AA1 axis during the progression of NSCLC. Although it was suggested that HSP90AA1 could be a potential target for NSCLC treatment, another protein-coding gene, NCOA2, might be relevant for gastric cancer, liver cancer, or prostate cancer [46–48]. Although many previous studies have hypothesized that NCOA2 might become a potential therapeutic target for NSCLC, further verification is still needed to validate it . PPARG expression may also act as a potential therapeutic agent for NSCLC, especially for lung squamous cell carcinoma (LSCC). Since the activation of PPARG expression can inhibit LSCC development and progress by regulating the upstream regulator and downstream marker genes, which are involved in tumor cell proliferation and protein polyubiquitination/ubiquitination . Another study suggested that the loss of NOS2 reduces the growth of lung tumors and the inflammation caused by oncogenic KRAS while stating that KRAS and NOS2 jointly promote the occurrence and inflammation of lung tumors . Moreover, inhibition of NOS2 may have therapeutic value for lung cancer with oncogenic KRAS mutations. It was also evident that highly methylated DNA, down-regulated PDE3A in chemoresistant NSCLC cells by forcing PDE3A expression to make A549/Cis cells sensitive to cisplatin. This result indicated that high PDE3A expression might promote the NSCLC treatment by increased efficacy of combination therapies . A network pharmacology study by Wang et al. on NSCLC did not find any effect of PDE3A on NSCLC . Moreover, in our study, the survival analysis of 10 main targets suggested that only PDE3A had statistical significance for the prognosis of NSCLC patients. The survival rate of PDE3A in the low expression group was higher than that in the high expression group, further confirming that reducing the expression of PDE3A may improve the quality of life of NSCLC patients. Meanwhile, through the Sankey diagram, it was evident that PDE3A was mainly distributed in the LU65 tumor cell line of NSCLC. Interestingly, the LU65 cell line originated in the Asian populations, especially East Asia, accounting for over 79.97% of inhabitants . Therefore, PDE3A might be a more suitable potential therapeutic target for Asian NSCLC patients. Wang et al. analyzed 12 human plasma samples by using RNA-Seq and bioinformatics techniques and found seven key targets related to lung tumorigenesis: COX1, COX2, COX3, ND1, ND2, ND4L, and ATP6 . A previous study demonstrated that the SCC pathogenesis caused by COPD is regulated by HSP90AA1, ADRB2, TBL1XR1, and HSPB1. Therefore, these genes can be used as potential therapeutic targets for the treatment of COPD-related SCC patients . A 2008 study observed that the use of real-time PCR to assess the methylation of the ESR1 promoter in the blood proved very useful for the diagnosis of lung cancer, as these methylated genes might become crucial biomarkers for the early detection of lung cancer. The results also indicated that a comparative evaluation of methylation ratios before and after surgery might be a powerful tool for predicting the prognosis of lung cancer patients . Simultaneously, it was suggested that ESR1 mRNA overexpression is innately associated with NSCLC prognosis . Therefore, ESR1 could also become an important key target for treating NSCLC, which is consistent with the results of Wang et al. . It was also estimated that as PRKACA was a tumor target, it might be helpful as therapy, but due to lack of evidence, its involvement in the development of lung cancer is debatable.
GO annotation is an important means to examine the function of gene products . Through GO functional enrichment analysis, this study inferred all the important biological processes, their cellular compositions, and intermolecular functions involved in the core targets. The details are displayed in Figure 7. In KEGG enrichment analysis, the results were mainly related to the AGE-RAGE signaling pathway in diabetic complications. Accumulation of AGEs and upregulated expression of RAGE is associated with various pathological conditions, including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer. The role of AGE-RAGE signaling has been previously demonstrated in the progression of various types of cancer and other pathological disorders . Therefore, the regulation of the AGE-RAGE signaling pathway is closely related to tumor development. In the molecular docking process, analysis of five main active ingredients with ten key core targets while calculating the affinity revealed that the affinity of quercetin and PTGS1 was the greatest (Affinity = –9.7 kJ·mol−1), while the binding energy of hederagenin and PDE3A was also good (Affinity = –8.9 kJ·mol−1). These results observed that, although PTGS1 and PDE3A might be the key targets in DBD for treating NSCLC, quercetin, and hederagenin may also be effective ingredients for the potential treatment of NSCLC.
However, it should be noted that our study was based on public databases, which had finite information and need to be continuously improved. Additionally, our study also overlooked the influence of concentration, picking time, processing method, and medication time of DBD on NSCLC. But overall, our study is worthy of further exploration and verification to extract the intricate molecular mechanisms governing therapeutic targets for NSCLC treatment.