Suppression of the NF‑κB signaling pathway in colon cancer cells by the natural compound Riccardin D from Dumortierahirsute

Bioinformatics screening of colorectal-cancer causing molecular signatures through gene expression profiles to discover therapeutic targets and candidate agents

BACKGROUND

Detection of appropriate receptor proteins and drug agents are equally important in the case of drug discovery and development for any disease. In this study, an attempt was made to explore colorectal cancer (CRC) causing molecular signatures as receptors and drug agents as inhibitors by using integrated statistics and bioinformatics approaches.

METHODS

To identify the important genes that are involved in the initiation and progression of CRC, four microarray datasets (GSE9348, GSE110224, GSE23878, and GSE35279) and an RNA_Seq profiles (GSE50760) were downloaded from the Gene Expression Omnibus database. The datasets were analyzed by a statistical r-package of LIMMA to identify common differentially expressed genes (cDEGs). The key genes (KGs) of cDEGs were detected by using the five topological measures in the protein-protein interaction network analysis. Then we performed in-silico validation for CRC-causing KGs by using different web-tools and independent databases. We also disclosed the transcriptional and post-transcriptional regulatory factors of KGs by interaction network analysis of KGs with transcription factors (TFs) and micro-RNAs. Finally, we suggested our proposed KGs-guided computationally more effective candidate drug molecules compared to other published drugs by cross-validation with the state-of-the-art alternatives of top-ranked independent receptor proteins.

RESULTS

We identified 50 common differentially expressed genes (cDEGs) from five gene expression profile datasets, where 31 cDEGs were downregulated, and the rest 19 were up-regulated. Then we identified 11 cDEGs (CXCL8, CEMIP, MMP7, CA4, ADH1C, GUCA2A, GUCA2B, ZG16, CLCA4, MS4A12 and CLDN1) as the KGs. Different pertinent bioinformatic analyses (box plot, survival probability curves, DNA methylation, correlation with immune infiltration levels, diseases-KGs interaction, GO and KEGG pathways) based on independent databases directly or indirectly showed that these KGs are significantly associated with CRC progression. We also detected four TFs proteins (FOXC1, YY1, GATA2 and NFKB) and eight microRNAs (hsa-mir-16-5p, hsa-mir-195-5p, hsa-mir-203a-3p, hsa-mir-34a-5p, hsa-mir-107, hsa-mir-27a-3p, hsa-mir-429, and hsa-mir-335-5p) as the key transcriptional and post-transcriptional regulators of KGs. Finally, our proposed 15 molecular signatures including 11 KGs and 4 key TFs-proteins guided 9 small molecules (Cyclosporin A, Manzamine A, Cardidigin, Staurosporine, Benzo[A]Pyrene, Sitosterol, Nocardiopsis Sp, Troglitazone, and Riccardin D) were recommended as the top-ranked candidate therapeutic agents for the treatment against CRC.

CONCLUSION

The findings of this study recommended that our proposed target proteins and agents might be considered as the potential diagnostic, prognostic and therapeutic signatures for CRC.

Medicinal Plants in Cancer Treatment: Contribution of Nuclear Factor-Kappa B (NF-kB) Inhibitors

Nuclear factor-kappa B (NF-κB) is one of the principal inducible proteins that is a predominant transcription factor known to control the gene expression in mammals and plays a pivotal role in regulating cell signalling in the body under certain physiological and pathological conditions. In cancer cells, such as colon, breast, pancreatic, ovarian, melanoma, and lymphoma, the NF-κB pathway has been reported to be active. In cellular proliferation, promoting angiogenesis, invasion, metastasis of tumour cells and blocking apoptosis, the constitutive activity of NF-κB signalling has been reported. Therefore, immense attention has been given to developing drugs targeting NF-κB signalling pathways to treat many types of tumours. They are a desirable therapeutic target for drugs, and many studies concentrated on recognizing compounds. They may be able to reverse or standstill the growth and spread of tumours that selectively interfere with this pathway. Recently, numerous substances derived from plants have been evaluated as possible inhibitors of the NF-κB pathway. These include various compounds, such as flavonoids, lignans, diterpenes, sesquiterpenes, polyphenols, etc. A study supported by folk medicine demonstrated that plant-derived compounds could suppress NF-κB signalling. Taking this into account, the present review revealed the anticancer potential of naturally occurring compounds which have been verified both by inhibiting the NF-κB signalling and suppressing growth and spread of cancer and highlighting their mechanism of NF-κB inhibition.

Survival of HT29 Cancer Cells Is Affected by IGF1R Inhibition via Modulation of Self-DNA-Triggered TLR9 Signaling and the Autophagy Response

Purpose: In HT29 colon cancer cells, a close interplay between self-DNA-induced TLR9 signaling and autophagy response was found, with remarkable effects on cell survival and differentiation. IGF1R activation drives the development and malignant progression of colorectal cancer. IGF1R inhibition displays a controversial effect on autophagy. The interrelated roles of IGF1R inhibition and TLR9/autophagy signaling in HT29 cancer cells have not yet been clarified. In our study, we aimed to investigate the complex interplay of IGF1R inhibition and TLR9/autophagy signaling in HT29 cells. Methods: HT29 cells were incubated with tumor-originated self-DNA with or without inhibitors of IGF1R (picropodophyllin), autophagy (chloroquine), and TLR9 (ODN2088), respectively. Cell proliferation and metabolic activity measurements, direct cell counting, NanoString and Taqman gene expression analyses, immunocytochemistry, WES Simple Western blot, and transmission electron microscopy investigations were performed. Results: The concomitant use of tumor-derived self-DNA and IGF1R inhibitors displays anti-proliferative potential, which can be reversed by parallel TLR9 signaling inhibition. The distinct effects of picropodophyllin, ODN2088, and chloroquine per se or in combination on HT29 cell proliferation and autophagy suggest that either the IGF1R-associated or non-associated autophagy machinery is "Janus-faced" regarding its actions on cell proliferation. Autophagy, induced by different combinations of self-DNA and inhibitors is not sufficient to rescue HT29 cells from death but results in the survival of some CD133-positive stem-like HT29 cells. Conclusion: The creation of new types of combined IGF1R, autophagy, and/or TLR9 signaling inhibitors would play a significant role in the development of more personalized anti-tumor therapies for colorectal cancer.

Survival of HT29 cancer cells is influenced by hepatocyte growth factor receptor inhibition through modulation of self-DNA-triggered TLR9-dependent autophagy response

HGFR activation drives the malignant progression of colorectal cancer, and its inhibition displays anti-autophagic activity. The interrelated role of HGFR inhibition and TLR9/autophagy signaling in HT29 cancer cells subjected to modified self-DNA treatments has not been clarified. We analyzed this complex interplay with cell metabolism and proliferation measurements, TLR9, HGFR and autophagy inhibitory assays and WES Simple Western blot-based autophagy flux measurements, gene expression analyses, immunocytochemistry, and transmission electron microscopy. The overexpression of MyD88 and caspase-3 was associated with enhanced HT29 cell proliferation, suggesting that incubation with self-DNAs could suppress the apoptosis-induced compensatory cell proliferation. HGFR inhibition blocked the proliferation-reducing effect of genomic and hypermethylated, but not that of fragmented DNA. Lowest cell proliferation was achieved with the concomitant use of genomic DNA, HGFR inhibitor, and chloroquine, when the proliferation stimulating effect of STAT3 overexpression could be outweighed by the inhibitory effect of LC3B, indicating the putative involvement of HGFR-mTOR-ULK1 molecular cascade in HGFR inhibitor-mediated autophagy. The most intense cell proliferation was caused by the co-administration of hypermethylated DNA, TLR9 and HGFR inhibitors, when decreased expression of both canonical and non-canonical HGFR signaling pathways and autophagy-related genes was present. The observed ultrastructural changes also support the context-dependent role of HGFR inhibition and autophagy on cell survival and proliferation. Further investigation of the influence of the studied signaling pathways and cellular processes can provide a basis for novel, individualized anti-cancer therapies.

Apoptotic effect of novel pyrazolone-based derivative [Cu(PMPP-SAL)(EtOH)] on HeLa cells and its mechanism

Pyrazolone complexes have strong anti-tumor and antibacterial properties, but the anti-tumor mechanism of pyrazolone-based copper complexes has not been fully understood. In this study, the possible mechanism and the inhibitory effect of a novel pyrazolone-based derivative compound [Cu(PMPP-SAL)(EtOH)] on human cervical cancer cells (HeLa cells) was investigated. [Cu(PMPP-SAL)(EtOH)] effectively inhibited proliferation of HeLa cells in vitro with an IC₅₀ value of 2.082 after treatment for 72 h. Cell cycle analysis showed apoptosis was induced by blocking the cell cycle in the S phase. [Cu(PMPP-SAL)(EtOH)] promoted the loss of mitochondrial membrane potential, release of cytochrome c, PARP cleavage, and activation of caspase-3/9 in HeLa cells. Additionally, [Cu(PMPP-SAL)(EtOH)] inhibited the PI3K/AKT pathway and activated the P38/MAPK, and JNK/MAPK pathways. [Cu(PMPP-SAL)(EtOH)] also inhibited the phosphorylation of Iκ-Bα in the NF-κB pathway activated by TNF-α, thus restricting the proliferation of HeLa cells which were activated by TNF-α. In conclusion, [Cu(PMPP-SAL)(EtOH)] inhibited the growth of HeLa cells and induced apoptosis possibly via the caspase-dependent mitochondria-mediated pathway. These results suggest that [Cu(PMPP-SAL)(EtOH)] can be a potential candidate for the treatment of cervical cancer.

Piperine Regulates Nrf-2/Keap-1 Signalling and Exhibits Anticancer Effect in Experimental Colon Carcinogenesis in Wistar Rats

Colon cancer is the most common cancer in men and women globally, killing millions of people annually. Though there widespread development has been made in the management of colorectal cancer, still there is an urgent need to find novel targets for its effective treatment. Piperine is an alkaloid found in black pepper having anticancer, anti-inflammatory activities, safe and nutritive for human consumption. Nuclear factor-erythroid 2-kelch-like ECH-associated protein 1(Nrf-2/Keap-1)/Heme-oxygenase1 (HO-1) signaling pathway plays a vital part in shielding cells from intracellular oxidative stress and inflammation. A potential cross-talk between the Nrf-2 and NF-κB pathways is recognized during cancerous growth and expansion. We studied this pathway extensively in the present study to discover novel targets in the prevention of chemically induced colon cancer with piperine to simulate human colon cancer pathology. Animals were divided into four groups. Groups1 and 2 were used as a negative control and positive control where 1,2-Dimethylhydrazine, DMH was administered in group 2, while group 3 and 4 were prevention groups where piperine at two different doses was given two weeks prior to DMH and continued until end of experiment. We found that piperine inhibited NF-κB by the activation of Nrf-2, blocking downstream inflammatory mediators/cytokines (TNF-α, IL-6, IL-1β, Cox-2, PGE-2, iNOS, NO, MPO), triggering an antioxidant response machinery (HO-1, NQO-1, GSH, GR, GPx, CAT, SOD), scavenging ROS, and decreasing lipid peroxidation. Histological findings further validated our molecular findings. It also downregulates CEA, MDF and ACF, markers of precancerous lesions in colon, alleviates infiltration of mast cells and depletes the mucous layer. Our results indicate that piperine may be an effective molecule for the prophylactic treatment of colon carcinogenesis by targeting the NF-κB/Nrf-2/Keap-1/HO-1 pathway as a progressive strategy in the preclusion and effective treatment of colorectal cancer.

Long non-coding RNA POU6F2-AS2 promotes cell proliferation and drug resistance in colon cancer by regulating miR-377/BRD4

The aim of this study was to explore the molecular mechanism of lncRNA POU6F2‐AS2 in proliferation and drug resistance of colon cancer. Total paired 70 colon cancer and adjacent normal tissues were collected from colon cancer patients. Colon cancer and normal colonic epithelial cells were purchased. POU6F2‐AS2 was up‐ or down‐expressed by vectors. LC50 of all cell lines before and after transfection with these plasmids was detected. qRT‐PCR was used to detect the expression of POU6F2‐AS2, miR‐377 and BRD4 before or after transfection. In situ hybridization was also undertaken to detect the level of POU6F2‐AS2. Different concentrations of 5‐Fu (0, 1, 2.5, 5, 10, 20, 40 and 80 μg/mL) were used for 5‐FU insensitivity assay. CCK‐8 and crystal violet staining assay were used for detecting cell proliferation, and flow cytometry was used for identifying cell cycle distribution and apoptosis. In order to detect the fragmented DNA in apoptotic cells, TUNEL assay was used. RNA pull‐down assay and luciferase reporter assay were used to verify the binding site. Rescue assay confirmed the subtractive effect of miR‐377 inhibitors. POU6F2‐AS2 was highly expressed in colon cancer, which was associated with clinical pathology. Up‐regulated POU6F2‐AS2 promoted cell proliferation and cell cycle of colon cancer cells. Overexpression of POU6F2‐AS2 inhibited the expression of miR‐377 and then up‐regulated the expression of BRD4. Up‐regulated BRD4 ultimately promoted cell proliferation and cell survival Down‐regulated POU6F2‐AS2 showed enhanced sensitivity of 5‐FU. POU6F2‐AS2 promoted cell proliferation and drug resistance in colon cancer by regulating miR‐377/BRD4 gene.

Nuclear Factor κB Signaling and Its Related Non-coding RNAs in Cancer Therapy

Nuclear factor κB (NF-κB) acts as a nuclear factor that is composed of five main subunits. It is a pluripotent and crucial dimer transcription factor that has a close relationship with many serious illnesses, especially its influences on cell proliferation, inflammation, and cancer initiation and progression. NF-κB acts as part of the signaling pathway and determines its effect on the expression of several other genes, such as epidermal growth factor receptor (EGFR), p53, signal transducer and activator of transcription 3 (STAT3), and non-coding RNA (ncRNA). Continuous activation of the NF-κB signaling pathway has been seen in many cancer types. While the NF-κB signaling pathway is tightly regulated in physiological settings, quite frequently it is constitutively activated in cancer, and the molecular biology mechanism underlying the deregulated activation of NF-κB signaling remains unclear. In this review, we discuss the regulatory role and possible clinical significance of ncRNA (microRNA [miRNA] and long non-coding RNA [lncRNA]) in NF-κB signaling in cancer, including in the conversion of inflammation to carcinogenesis. Non-coding RNA plays an essential and complex role in the NF-κB signaling pathway. NF-κB activation can also induce the ncRNA status. Targeting NF-κB signaling by ncRNA is becoming a promising strategy of drug development and cancer treatment.

Benzophenones from Anemarrhena asphodeloides Bge. Exhibit Anticancer Activity in HepG2 Cells via the NF-κB Signaling Pathway

A chemical investigation of the fibrous roots of Anemarrhena asphodeloides Bge. led to the isolation of four benzophenones, including one new compound (1) and three known ones (2–4). Comprehensive ¹D, ²D NMR and HRESIMS data established the structures of the isolated compounds. The absolute configurations were determined by comparison of the calculated optical rotation (OR) with experimental data. All the isolates were evaluated for their cytotoxicities on hepatocellular carcinoma cell lines (HepG2 and Hep3B). Compound 1 showed strong cytotoxicity against HepG2 and Hep3B cells, with IC₅₀ values at 153.1 and 180.6 nM. Through MTT assay, flow cytometry and Western blot analysis, compound 1 demonstrated the ability to stimulate apoptosis via the NF-κB signaling pathway in HepG2 cells. These benzophenones are potential lead compounds for the development of better treatments for hepatocellular carcinoma.