Down-regulation of epidermal growth factor receptor by curcumin-induced UBE1L in human bronchial epithelial cells

Identifying the Antitumor Effects of Curcumin on Lung Adenocarcinoma Using Comprehensive Bioinformatics Analysis

Background

As the main component of turmeric (Curcuma longa L.), curcumin is widely used in the treatment of various diseases. Previous studies have demonstrated that curcumin has great potential as a therapeutic agent, but the lack of understanding of the functional mechanism of the drug has hindered the widespread use of the natural product. In the present study, we used comprehensive bioinformatics analysis and in vitro experiments to explore the anti-tumor mechanism of curcumin.

Materials and Methods

LUAD mRNA expression data were obtained from TCGA database and differentially expressed genes (DEGs) were identified using R software. Functional enrichment analysis was conducted to further clarify its biological properties and hub genes were identified by a protein–protein interaction (PPI) network analysis. Survival analysis and molecular docking were used to analyze the effectiveness of the hub genes. By an in vitro study, we evaluated whether curcumin could influence the proliferation, migration, and invasion activities of LUAD cells.

Results

In this study, 1783 DEGs from LUAD tissue samples compared to normal samples were evaluated. Functional enrichment analysis and the PPI network revealed the characteristics of the DEGs. We performed a topological analysis and identified 10 hub genes. Of these, six genes (INS, GCG, SST, F2, AHSG, and NPY) were identified as potentially effective biomarkers of LUAD. The molecular docking results indicated that curcumin targets in regulating lung cancer may be INS and GCG. We found that curcumin significantly inhibited the proliferation, migration, and invasion of LUAD cells and significantly decreased the expression of the INS and GCG genes.

Conclusion

The results of this study suggest that the therapeutic effects of curcumin on LUAD may be achieved through the intervention of INS and GCG, which may act as potential biomarkers for LUAD prevention and treatment.

Single-Molecule RNA Sequencing Reveals IFNγ-Induced Differential Expression of Immune Escape Genes in Merkel Cell Polyomavirus-Positive MCC Cell Lines

Merkel cell carcinoma (MCC) is a rare and highly aggressive cancer, which is mainly caused by genomic integration of the Merkel cell polyomavirus and subsequent expression of a truncated form of its large T antigen. The resulting primary tumor is known to be immunogenic and under constant pressure to escape immune surveillance. Because interferon gamma (IFNγ), a key player of immune response, is secreted by many immune effector cells and has been shown to exert both anti-tumoral and pro-tumoral effects, we studied the transcriptomic response of MCC cells to IFNγ. In particular, immune modulatory effects that may help the tumor evade immune surveillance were of high interest to our investigation. The effect of IFNγ treatment on the transcriptomic program of three MCC cell lines (WaGa, MKL-1, and MKL-2) was analyzed using single-molecule sequencing via the Oxford Nanopore platform. A significant differential expression of several genes was detected across all three cell lines. Subsequent pathway analysis and manual annotation showed a clear upregulation of genes involved in the immune escape of tumor due to IFNγ treatment. The analysis of selected genes on protein level underlined our sequencing results. These findings contribute to a better understanding of immune escape of MCC and may help in clinical treatment of MCC patients. Furthermore, we demonstrate that single-molecule sequencing can be used to assess characteristics of large eukaryotic transcriptomes and thus contribute to a broader access to sequencing data in the community due to its low cost of entry.

Receptor Tyrosine Kinases and Their Signaling Pathways as Therapeutic Targets of Curcumin in Cancer

Receptor tyrosine kinases (RTKs) are transmembrane cell-surface proteins that act as signal transducers. They regulate essential cellular processes like proliferation, apoptosis, differentiation and metabolism. RTK alteration occurs in a broad spectrum of cancers, emphasising its crucial role in cancer progression and as a suitable therapeutic target. The use of small molecule RTK inhibitors however, has been crippled by the emergence of resistance, highlighting the need for a pleiotropic anti-cancer agent that can replace or be used in combination with existing pharmacological agents to enhance treatment efficacy. Curcumin is an attractive therapeutic agent mainly due to its potent anti-cancer effects, extensive range of targets and minimal toxicity. Out of the numerous documented targets of curcumin, RTKs appear to be one of the main nodes of curcumin-mediated inhibition. Many studies have found that curcumin influences RTK activation and their downstream signaling pathways resulting in increased apoptosis, decreased proliferation and decreased migration in cancer both in vitro and in vivo. This review focused on how curcumin exhibits anti-cancer effects through inhibition of RTKs and downstream signaling pathways like the MAPK, PI3K/Akt, JAK/STAT, and NF-κB pathways. Combination studies of curcumin and RTK inhibitors were also analysed with emphasis on their common molecular targets.

Circulating Tumour Cells (CTCs) in NSCLC: From Prognosis to Therapy Design

Designing optimal (neo)adjuvant therapy is a crucial aspect of the treatment of non-small-cell lung carcinoma (NSCLC). Standard methods of chemotherapy, radiotherapy, and immunotherapy represent effective strategies for treatment. However, in some cases with high metastatic activity and high levels of circulating tumour cells (CTCs), the efficacy of standard treatment methods is insufficient and results in treatment failure and reduced patient survival. CTCs are seen not only as an isolated phenomenon but also a key inherent part of the formation of metastasis and a key factor in cancer death. This review discusses the impact of NSCLC therapy strategies based on a meta-analysis of clinical studies. In addition, possible therapeutic strategies for repression when standard methods fail, such as the administration of low-toxicity natural anticancer agents targeting these phenomena (curcumin and flavonoids), are also discussed. These strategies are presented in the context of key mechanisms of tumour biology with a strong influence on CTC spread and metastasis (mechanisms related to tumour-associated and -infiltrating cells, epithelial–mesenchymal transition, and migration of cancer cells).

pH-responsive hyaluronic acid-based nanoparticles for targeted curcumin delivery and enhanced cancer therapy

Curcumin (CUR) display promising antitumor effects, however, the poor water solubility severely limited its clinical application. To overcome this problem, polymeric nanocarriers have been adopted for targeted CUR delivery and enhanced cancer therapy. In this paper, utilizing an acid-labile hydrazone linkage, hydrophobic CUR was conjugated with hydrophilic hyaluronic acid (HA) to form amphiphilic HA-ADH-CUR conjugates, which could subsequently self-assemble to form nanoparticles (HA@CUR NPs) in aqueous. The in vitro drug release experiments showed that HA@CUR NPs exhibited a pH-responsive CUR release behavior, and the release rate of CUR was 73.5 % in pH 5.0. Further, in vitro cell experiments showed HA@CUR NPs could be efficiently internalized by 4T1 and MCF-7 cancer cells through CD44 receptor mediated endocytosis and successfully release CUR in acidic lysosome environment for chemotherapy. In vivo antitumor experiments showed that, compared to free CUR, HA@CUR NPs could efficiently cumulate in tumor site via EPR effect and CD44 mediated endocytosis, achieve superior therapeutic effect for tumor growth suppression. Therefore, HA@CUR NPs were a highly promising nanocarrier for hydrophobic CUR to realize enhanced cancer therapy with good biosafety.

Ubiquitin-like modifier-activating enzyme 7 as a marker for the diagnosis and prognosis of breast cancer

Ubiquitin-like modifier-activating enzyme 7 (UBA7) is a specific E1-like ubiquitin-activating enzyme involved in interferon-stimulated gene 15 (ISG15) conjugation. UBA7 expression has been reported to be notably decreased in lung cancer. The present study aimed to investigate the changes in UBA7 expression in breast cancer and the association between UBA7 expression and clinical characteristics, and to elucidate the diagnostic and prognostic significance of UBA7 in breast cancer. The clinical data and RNA-sequencing expression values of 1,104 patients with breast cancer were downloaded from The Cancer Genome Atlas database. The associations between UBA7 expression and clinical characteristics were determined using χ² and Fisher's exact tests. UBA7 expression values were divided into low and high groups using the optimal cut-off value, as determined by the overall survival (OS) value identified via a receiver operating characteristic (ROC) curve analysis, to further study the association between UBA7 expression and clinical characteristics. The diagnostic capability of UBA7 was assessed via ROC analysis, and Kaplan-Meier curve and Cox regression analyses were performed to determine the prognostic value of UBA7. The results demonstrated that UBA7 expression was decreased in breast cancer, and significant differences were observed between groups with regards to vital status, tumor classification, metastasis classification, histological type, sex, molecular subtype, and expression levels of progesterone receptor, estrogen receptor (ER) and human epidermal growth factor receptor 2. Low and high UBA7 expression levels were associated with age, ER expression, menopause status, Tumor-Node-Metastasis classification stage, margin status, vital status, radiation therapy use, OS and relapse-free survival. Furthermore, patients with low UBA7 expression levels had a poor prognosis. UBA7 expression also demonstrated an ability to diagnose patients at all clinical stages. Taken together, the results indicated that UBA7 expression was significantly decreased in breast cancer, and was associated with clinical characteristics and prognosis. Thus, UBA7 can be deemed as a potential biomarker in breast cancer, and may serve as a target in treatment.

Mechanistic Understanding of Curcumin's Therapeutic Effects in Lung Cancer

Lung cancer is among the most common cancers with a high mortality rate worldwide. Despite the significant advances in diagnostic and therapeutic approaches, lung cancer prognoses and survival rates remain poor due to late diagnosis, drug resistance, and adverse effects. Therefore, new intervention therapies, such as the use of natural compounds with decreased toxicities, have been considered in lung cancer therapy. Curcumin, a natural occurring polyphenol derived from turmeric (Curcuma longa) has been studied extensively in recent years for its therapeutic effects. It has been shown that curcumin demonstrates anti-cancer effects in lung cancer through various mechanisms, including inhibition of cell proliferation, invasion, and metastasis, induction of apoptosis, epigenetic alterations, and regulation of microRNA expression. Several in vitro and in vivo studies have shown that these mechanisms are modulated by multiple molecular targets such as STAT3, EGFR, FOXO3a, TGF-β, eIF2α, COX-2, Bcl-2, PI3KAkt/mTOR, ROS, Fas/FasL, Cdc42, E-cadherin, MMPs, and adiponectin. In addition, limitations, strategies to overcome curcumin bioavailability, and potential side effects as well as clinical trials were also reviewed.

Curcumin suppresses MUC5AC production via interfering with the EGFR signaling pathway

Excessive mucin production in the airway may contribute to airway inflammatory diseases. Curcumin has been reported to prevent mucin 5AC (MUC5AC) production in human airway epithelial cells; however, the molecular targets of curcumin involved in regulating MUC5AC expression have remained elusive. The present study aimed to elucidate the molecular mechanisms by which curcumin regulates MUC5AC production, utilizing the NCI‑H292 human airway epithelial cell line featuring MUC5AC hypersecretion. Curcumin was able to counteract the endothelial growth factor (EGF)‑stimulated mRNA and protein expression of MUC5AC. In addition, curcumin treatment prevented EGF‑induced phosphorylation of EGF receptor (EGFR) as well as the downstream AKT and signal transducer and activator of transcription 3 (STAT3), while inhibition of PI3K and STAT3 signaling significantly attenuated the expression of MUC5AC that was induced by EGF. Furthermore, EGF‑induced increases in the levels of phosphorylated STAT3 in the nuclear fraction were inhibited by curcumin and PI3K inhibitors. In addition, treatment with curcumin significantly decreased MUC5AC and EGFR expression in a time‑dependent manner under basal conditions. These results demonstrated that curcumin inhibited MUC5AC protein expression in NCI‑H292 cells under basal conditions as well under EGF stimulation. This inhibition was accompanied by decreased activation of the EGFR/AKT/STAT3 pathway and reduced EGFR expression, which indicated that curcumin may have a dual role in interfering with the EGFR signaling pathway and inhibiting mucin expression in human airway epithelial cells.

Therapeutic Potential of Novel Nano-Based Curcumin Compounds In Vitro and In Vivo

Despite recent advances in cancer medication, malignant tumors continue to be the second leading cause of death worldwide. Furthermore, introducing a therapeutic compound with low-side effects as well as low-price for consumers is controversial. Recent efforts have been focusing on traditional medicines as a rich source of herbal agents. Curcumin, the major turmeric phytochemical, has been widely assessed as an anti-cancer compound in vitro and in vivo. However, the use of curcumin in cancer treatment has limitations because of its low solubility, poor tissue absorption, rapid metabolism and rapid systemic elimination. Recent work has focused on improving the stability of curcumin to facilitate clinical application. Dendrosomal nano-corcumin (DNC) is one of the most successful compounds showing significant cellular absorption and also anti-tumor effects. The present overview of newest applicable strategies for curcumin-based therapy and their clinical potential usefulness has the emphasis on DNC.

Curcumin induces apoptosis in SGC-7901 gastric adenocarcinoma cells via regulation of mitochondrial signaling pathways

Curcumin, a polyphenol compound derived from the rhizome of the plant Curcuma longa L. has been verified as an anticancer compound against several types of cancer. However, understanding of the molecular mechanisms by which it induces apoptosis is limited. In this study, the anticancer efficacy of curcumin was investigated in human gastric adenocarcinoma SGC-7901 cells. The results demonstrated that curcumin induced morphological changes and decreased cell viability. Apoptosis triggered by curcumin was visualized using Annexin V-FITC/7- AAD staining. Curcumin-induced apoptosis of SGC-7901 cells was associated with the dissipation of mitochondrial membrane potential (MMP) and the release of cytochrome c into the cytosol. Furthermore, the down-regulation of Bcl-2 and up-regulation of Bax that led to the cleavage of caspase-3 and increased cleaved PARP was observed in SGC-7901 cells treated with curcumin. Therefore, curcumin-induced apoptosis of SGC-7901 cells might be mediated through the mitochondria pathway, which gives the rationale for in vivo studies on the utilization of curcumin as a potential cancer therapeutic compound.

Curcumin inhibits lymphangiogenesis in vitro and in vivo

SCOPE

Curcumin, a dietary compound from turmeric, has potent antimetastatic effects; however, the underlying mechanisms are not well understood. The aim of this study is to investigate the effects and mechanisms of curcumin on lymphangiogenesis (formation of new lymphatic vessels), which plays a critical role in tumor metastasis.

METHODS AND RESULTS

Curcumin inhibited vascular endothelial growth factor-C (VEGF-C) induced lymphangiogenesis in a Matrigel plug assay in mice, and VEGF-C induced tube formation in human dermal lymphatic endothelial cells, demonstrating its antilymphangiogenic action in vivo and in vitro. Curcumin inhibited lymphangiogenesis, in part through suppression of proliferation, cell-cycle progression and migration of lymphatic endothelial cells, while it had little effect on matrix metalloproteinase activities. Curcumin inhibited expressions of VEGF receptors (VEGFR2 and VEGFR3), as well as downstream signaling such as phosphorylation of ERK and FAK. Finally, curcumin sulfate and curcumin glucuronide, which are two major metabolites of curcumin in vivo, had little inhibitory effect on proliferation of human dermal lymphatic endothelial cells.

CONCLUSION

Our results demonstrate that curcumin inhibits lymphangiogenesis in vitro and in vivo, which could contribute to the antimetastatic effects of curcumin.

The multifaceted role of curcumin in cancer prevention and treatment

Despite significant advances in treatment modalities over the last decade, neither the incidence of the disease nor the mortality due to cancer has altered in the last thirty years. Available anti-cancer drugs exhibit limited efficacy, associated with severe side effects, and are also expensive. Thus identification of pharmacological agents that do not have these disadvantages is required. Curcumin, a polyphenolic compound derived from turmeric (Curcumin longa), is one such agent that has been extensively studied over the last three to four decades for its potential anti-inflammatory and/or anti-cancer effects. Curcumin has been found to suppress initiation, progression, and metastasis of a variety of tumors. These anti-cancer effects are predominantly mediated through its negative regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other oncogenic molecules. It also abrogates proliferation of cancer cells by arresting them at different phases of the cell cycle and/or by inducing their apoptosis. The current review focuses on the diverse molecular targets modulated by curcumin that contribute to its efficacy against various human cancers.