Curcumin Reverses NNMT-Induced 5-Fluorouracil Resistance via Increasing ROS and Cell Cycle Arrest in Colorectal Cancer Cells

Nicotinamide N-Methyltransferase (NNMT): A New Hope for Treating Aging and Age-Related Conditions

The complex process of aging leads to a gradual deterioration in the function of cells, tissues, and the entire organism, thereby increasing the risk of disease and death. Nicotinamide N-methyltransferase (NNMT) has attracted attention as a potential target for combating aging and its related pathologies. Studies have shown that NNMT activity increases over time, which is closely associated with the onset and progression of age-related diseases. NNMT uses S-adenosylmethionine (SAM) as a methyl donor to facilitate the methylation of nicotinamide (NAM), converting NAM into S-adenosyl-L-homocysteine (SAH) and methylnicotinamide (MNA). This enzymatic action depletes NAM, a precursor of nicotinamide adenine dinucleotide (NAD+), and generates SAH, a precursor of homocysteine (Hcy). The reduction in the NAD+ levels and the increase in the Hcy levels are considered important factors in the aging process and age-related diseases. The efficacy of RNA interference (RNAi) therapies and small-molecule inhibitors targeting NNMT demonstrates the potential of NNMT as a therapeutic target. Despite these advances, the exact mechanisms by which NNMT influences aging and age-related diseases remain unclear, and there is a lack of clinical trials involving NNMT inhibitors and RNAi drugs. Therefore, more in-depth research is needed to elucidate the precise functions of NNMT in aging and promote the development of targeted pharmaceutical interventions. This paper aims to explore the specific role of NNMT in aging, and to evaluate its potential as a therapeutic target.

Curcumin suppresses colorectal cancer by induction of ferroptosis via regulation of p53 and solute carrier family 7 member 11/glutathione/glutathione peroxidase 4 signaling axis

Driven by iron-dependent lipid peroxidation, ferroptosis is regulated by p53 and solute carrier family 7 member 11 (SLC7A11)/glutathione/glutathione peroxidase 4 (GPX4) axis in colorectal cancer (CRC). This study aimed to investigate the influence of curcumin (CUR) on ferroptosis in CRC. The efficacies of CUR on the malignant phenotype of CRC cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, wound healing, and clonogenic assays. The effects of CUR on ferroptosis of CRC cells were evaluated by transmission electron microscopy, lactate dehydrogenase release assay, Fe2+ staining, and analyses of reactive oxygen species, lipid peroxide, malondialdehyde, and glutathione levels. CUR's targets in ferroptosis were predicted by network pharmacological study and molecular docking. With SW620 xenograft tumors, the efficacy of CUR on CRC was investigated, and the effects of CUR on ferroptosis were assessed by detection of Fe2+, malondialdehyde, and glutathione levels. The effects of CUR on expressions of p53, SLC7A11, and GPX4 in CRC cells and tumors were analyzed by quantitative reverse transcription-polymerase chain reaction, western blotting, and immunohistochemistry. CUR suppressed the proliferation, migration, and clonogenesis of CRC cells and xenograft tumor growth by causing ferroptosis, with enhanced lactate dehydrogenase release and Fe2+, reactive oxygen species, lipid peroxide, and malondialdehyde levels, but attenuated glutathione level in CRC. In silico study indicated that CUR may bind p53, SLC7A11, and GPX4, consolidated by that CUR heightened p53 but attenuated SLC7A11 and GPX4 mRNA and protein levels in CRC. CUR may exert an inhibitory effect on CRC by inducing ferroptosis via regulation of p53 and SLC7A11/glutathione/GPX4 axis.

Targeting nicotinamide N-methyltransferase decreased aggressiveness of osteosarcoma cells

BACKGROUND

Osteosarcoma (OS) is a primary bone malignancy that mostly affects young people, characterized by high metastatic potential, and a marked chemoresistance that is responsible for disease relapse in most patients. Therefore, it is necessary to identify novel molecules to setup targeted strategies to improve the clinical outcome. The enzyme nicotinamide N-methyltransferase (NNMT) catalyses the N-methylation of nicotinamide and other analogs, playing a crucial role in the biotransformation of drugs and xenobiotics. NNMT overexpression was reported in a wide variety of cancers, and several studies demonstrated that is able to promote cell proliferation, migration and resistance to chemotherapy. The aim of this study was to explore the potential involvement of NNMT in OS.

METHODS

Immunohistochemical analyses have been performed to evaluate NNMT expression in selected OS and healthy bone tissue samples. Subsequently, OS cell lines have been transfected with vectors targeting NNMT mRNA (shRNAs) and the impact of this downregulation on migration, cell proliferation, and response to chemotherapeutic treatment was also analysed by wound healing, MTT, SRB and Trypan blue assays, respectively.

RESULTS

Results showed that OS samples display a significantly higher NNMT expression compared with healthy tissue. Preliminary results suggest that NNMT silencing in OS cell lines is associated to a decrease of cell proliferation and migration, as well as to enhanced sensitivity to chemotherapy. Data obtained showed that NNMT may represent an interesting marker for OS detection and a promising target for effective anti-cancer therapy.

Wnt/β-catenin signalling, epithelial-mesenchymal transition and crosslink signalling in colorectal cancer cells

Colorectal cancer (CRC), with its significant incidence and metastatic rates, profoundly affects human health. A common oncogenic event in CRC is the aberrant activation of the Wnt/β-catenin signalling pathway, which drives both the initiation and progression of the disease. Persistent Wnt/β-catenin signalling facilitates the epithelial-mesenchymal transition (EMT), which accelerates CRC invasion and metastasis. This review provides a summary of recent molecular studies on the role of the Wnt/β-catenin signalling axis in regulating EMT in CRC cells, which triggers metastatic pathogenesis. We present a comprehensive examination of the EMT process and its transcriptional controllers, with an emphasis on the crucial functions of β-catenin, EMT transcription factors (EMT-TFs). We also review recent evidences showing that hyperactive Wnt/β-catenin signalling triggers EMT and metastatic phenotypes in CRC via "Destruction complex" of β-catenin mechanisms. Potential therapeutic and challenges approache to suppress EMT and prevent CRC cells metastasis by targeting Wnt/β-catenin signalling are also discussed. These include direct β-catenin inhibitors and novel targets of the Wnt pathway, and finally highlight novel potential combinational treatment options based on the inhibition of the Wnt pathway.

Pan-cancer analysis combined with experiments predicts NNMT as a therapeutic target for human cancers

The identification of effective therapeutic targets plays a pivotal role in advancing cancer treatment outcomes. We employed a comprehensive pan-cancer analysis, complemented by experimental validation, to explore the potential of Nicotinamide N-methyltransferase (NNMT) as a promising therapeutic strategy for human cancers. By analyzing large-scale transcriptomic datasets across various cancer types, we consistently observed upregulated expression of NNMT. Furthermore, elevated NNMT expression correlated with inferior overall survival in multiple cancer cohorts, underscoring its significance as a prognostic biomarker. Additionally, we investigated the relationship between NNMT expression and the tumor immune microenvironment, which plays a crucial role in regulating anti-tumor immune responses. To confirm the malignant functions of NNMT in tumor cells, we conducted a series of cell-based experiments, revealing that NNMT promotes cancer cell proliferation and invasion, indicative of its oncogenic properties. The integration of computational analysis and experimental validation in our study firmly establishes NNMT as a potential therapeutic target for human cancers. Specifically, targeting NNMT holds promise for the development of innovative and effective cancer treatments. Further investigations into NNMT's role in cancer pathogenesis could potentially pave the way for groundbreaking advancements in cancer treatment.

Role of Epigenetic Modulation in Neurodegenerative Diseases: Implications of Phytochemical Interventions

Epigenetics defines changes in cell function without involving alterations in DNA sequence. Neuroepigenetics bridges neuroscience and epigenetics by regulating gene expression in the nervous system and its impact on brain function. With the increase in research in recent years, it was observed that alterations in the gene expression did not always originate from changes in the genetic sequence, which has led to understanding the role of epigenetics in neurodegenerative diseases (NDDs) including Alzheimer's disease (AD) and Parkinson's disease (PD). Epigenetic alterations contribute to the aberrant expression of genes involved in neuroinflammation, protein aggregation, and neuronal death. Natural phytochemicals have shown promise as potential therapeutic agents against NDDs because of their antioxidant, anti-inflammatory, and neuroprotective effects in cellular and animal models. For instance, resveratrol (grapes), curcumin (turmeric), and epigallocatechin gallate (EGCG; green tea) exhibit neuroprotective effects through their influence on DNA methylation patterns, histone acetylation, and non-coding RNA expression profiles. Phytochemicals also aid in slowing disease progression, preserving neuronal function, and enhancing cognitive and motor abilities. The present review focuses on various epigenetic modifications involved in the pathology of NDDs, including AD and PD, gene expression regulation related to epigenetic alterations, and the role of specific polyphenols in influencing epigenetic modifications in AD and PD.

Network pharmacology and molecular docking reveal the mechanisms of curcumin activity against esophageal squamous cell carcinoma

Background: Curcumin (CUR), an effective traditional Chinese medicinal extract, displays good anti-cancer activity against various cancers. Nevertheless, the impacts and fundamental mechanisms of CUR to treat esophageal squamous cell carcinoma (ESCC) yet to be comprehensively clarified. This study examined the suppressive impacts of CUR on ESCC. Methods: For a comprehensive understanding of the effect of CUR in ESCC. The CUR targets and ESCC-related genes were identified respectively, and the intersection targets between CUR and ESCC were acquired. Then, we examined the intersection targets and discovered genes that were expressed differently in ESCC. Using DAVID, enrichment analyses were conducted on the targets of CUR-ESCC. The STRING database and Cytoscape v.3.9.1 were utilized to build networks for protein-protein interaction (PPI) and drug-target-pathway. Furthermore, the interactions between CUR and its core targets were confirmed by molecular docking studies. To confirm the effects of CUR on ESCC cells, in vitro experiments were finally conducted. Results: Overall, 47 potential CUR targets for ESCC treatment were identified. The KEGG pathway enrichment analysis identified 61 signaling pathways, primarily associated with the FoxO signaling, the cell cycle, cellular senescence, the IL-17 signaling pathway which play important roles in ESCC progression. In the PPI network and the docking results identified CHEK1 and CDK6 as the core targets that positively associated with ESCC survival. CUR arrested ESCC cells at the G2/M and S phases, as shown by flow cytometry. Colony formation and CCK8 assays showed that CUR can inhibit the proliferative ability of ESCC cells. The Transwell invasion results validated that CUR can significantly inhibit the invasion rates of ESCC cells. Conclusion: Collectively, these findings indicate that CUR exhibits pharmacological effects on multiple targets and pathways in ESCC.

Curcumin inhibits the development of colorectal cancer via regulating the USP4/LAMP3 pathway

In this study, we aimed to explore the effects of curcumin on the progression of colorectal cancer and its underlying mechanisms involved. Cell proliferation, apoptosis and invasion were determined through CCK-8 assay, colony formation assay, EdU assay, flow cytometry, and transwell invasion assay, respectively. The protein expression of Bax, MMP2, USP4 and LAMP3 was measured using western blot. Pearson correlation coefficient was used to evaluate the relationship between USP4 and LAMP3. Co-IP was also conducted to determine the interaction between USP4 and LAMP3. Xenograft tumor model was established to explore the role of curcumin in colorectal cancer in vivo. IHC was utilized to measure the expression of Bax, MMP2, USP4 and LAMP3 in tumor tissues from mice. Curcumin significantly accelerated cell apoptosis, and inhibited cell proliferation and invasion in LoVo and HCT-116 cells. LAMP3 was augmented in colorectal cancer tissues and cells, and curcumin could reduce the expression of LAMP3. Curcumin decreased LAMP3 expression to exhibit the inhibition role in the progression of colorectal cancer. USP4 interacted with LAMP3, and positively regulated LAMP3 expression in colorectal cancer cells. LAMP3 overexpression could reverse the suppressive effects of USP4 knockdown on the development of colorectal cancer. Curcumin downregulated USP4 to impeded the progression of colorectal cancer via repressing LAMP3 expression. In addition, curcumin obviously restrained tumor growth in mice through downregulating USP4 and LAMP3 expression. These data indicated that curcumin exert the anti-tumor effects on the development of colorectal cancer through modulating the USP4/LAMP3 pathway.

Application of calcium overload-based ion interference therapy in tumor treatment: strategies, outcomes, and prospects

Low selectivity and tumor drug resistance are the main hinderances to conventional radiotherapy and chemotherapy against tumor. Ion interference therapy is an innovative anti-tumor strategy that has been recently reported to induce metabolic disorders and inhibit proliferation of tumor cells by reordering bioactive ions within the tumor cells. Calcium cation (Ca2+) are indispensable for all physiological activities of cells. In particular, calcium overload, characterized by the abnormal intracellular Ca2+ accumulation, causes irreversible cell death. Consequently, calcium overload-based ion interference therapy has the potential to overcome resistance to traditional tumor treatment strategies and holds promise for clinical application. In this review, we 1) Summed up the current strategies employed in this therapy; 2) Described the outcome of tumor cell death resulting from this therapy; 3) Discussed its potential application in synergistic therapy with immunotherapy.

Sclareol induces cell cycle arrest and ROS-mediated apoptosis and ferroptosis in lung adenocarcinoma cells

Sclareol (SC) has shown significant anticancer activity against breast and colon cancers among others. However, its ability to precipitate similar anticancer effects in lung cancer has yet to be investigated. To address this issue, SC-treated lung adenocarcinoma cells (A549) were assessed for viability and functional competence as well as the expression of genes related to apoptosis and cell cycling. Our results demonstrated that SC treatment inhibited A549 cell clonogenic features and reduced their migration and invasion potential in a dose-dependent manner. Mechanistically, SC treatment downregulated the expression of cyclin D1 and survivin and upregulated that of p21 and p16, which was associated with a significant increase in the percentage of SubG0 cells. SC treatment is also associated with the induction of both the extrinsic and intrinsic apoptotic pathways, as evidenced by the increased expression and splitting of PARP1 and procaspases 3 and 9 and the reduced expression of antiapoptotic proteins Bcl-2 and Bcl-xL. Increased cell death in SC-treated cells is likely to have resulted from the induction of ferroptosis as suggested by the reduced expression of FPN and the inhibition of the anti-ferroptosis regulator GPX4. In conclusion, the data presented here suggest that SC can reduce lung carcinoma cell growth and metastasis and promote cell death.

Corilagin enhances the anti-tumor activity of 5-FU by downregulating the expression of GRP 78

Colorectal cancer is one of the most common malignancies worldwide. Although initially effective, patients who receive chemotherapy ultimately experience various complications and develop chemo-resistance, leading to cancer recurrence. Therefore, we aimed to find a drug with good efficacy and low toxicity that could enhance the treatment with 5-Fluorouracil (a commonly used clinical drug) and reduce its dosing. Corilagin, an anti-tumor natural product, has received widespread attention. Glucose regulated protein 78 (GRP78) is overexpressed in colorectal cancer cells and plays a key role in the proliferation, migration and drug resistance of cancer cells. Importantly, GRP78 can affect the apoptosis induced by 5-fluorouracil in CRC cells. In the present study, we determined the synergistic anti-tumor activity of the combination treatment by cell proliferation assay, apoptosis assay, fluorescent staining, cell cycle analysis, WB and PCR assays. This synergistic effect was associated with S-phase blockade, intracellular reactive oxygen species production and downregulation of GRP78. Taken together, our results indicate that Corilagin acts as a potentiator of 5-fluorouracil and may have therapeutic potential for patients with CRC.

Curcumin Induces Apoptosis by Suppressing XRCC4 Expression in Hepatocellular Carcinoma

Curcumin is a chemical with various pharmacological activities used for cancer treatment. It inhibits hepatocellular carcinoma (HCC) by inducing apoptosis. Here, the mechanism underlying the effect of curcumin on the apoptosis of HCC cells was studied. Cell counting kit-8 and plate cloning assays were used to assess the proliferation of HCC cells, and acridine orange/ethidium bromide and Annexin V/PI staining were used to analyze their apoptosis. HCC xenograft tumor models were established to validate anti-cancer effects of curcumin. Expression levels of XRCC4 protein in tumor tissues were assessed by immunohistochemistry. Correlation between XRCC4 expression and the prognosis of patients with HCC was analyzed by integrating publicly available gene expression data. Curcumin inhibited HCC cells proliferation in a dose-dependent manner. Compared with the control group, curcumin significantly promoted the apoptosis of HCC cells in vitro and in vivo. Immunohistochemical analysis revealed that curcumin downregulated XRCC4 expression levels in HCC tissues. Prognosis of HCC patients with high XRCC4 expression was poorer than that of patients with low XRCC4 expression. Therefore, curcumin exerts anti-cancer effects by inhibiting cell proliferation and promoting cell apoptosis in HCC. This may be due to curcumin interference in the repair process of the nonhomologous DNA terminal link of HCC cells by downregulating XRCC4 expression.

An Overview of the Enhanced Effects of Curcumin and Chemotherapeutic Agents in Combined Cancer Treatments

Due to the progressive ageing of the human population, the number of cancer cases is increasing. For this reason, there is an urgent need for new treatments that can prolong the lives of cancer patients or ensure them a good quality of life. Although significant progress has been made in the treatment of cancer in recent years and the survival rate of patients is increasing, limitations in the use of conventional therapies include the frequent occurrence of side effects and the development of resistance to chemotherapeutic agents. These limitations are prompting researchers to investigate whether combining natural agents with conventional drugs could have a positive therapeutic effect in cancer treatment. Several natural bioactive compounds, especially polyphenols, have been shown to be effective against cancer progression and do not exert toxic effects on healthy tissues. Many studies have investigated the possibility of combining polyphenols with conventional drugs as a novel anticancer strategy. Indeed, this combination often has synergistic benefits that increase drug efficacy and reduce adverse side effects. In this review, we provide an overview of the studies describing the synergistic effects of curcumin, a polyphenol that has been shown to have extensive cytotoxic functions against cancer cells, including combined treatment. In particular, we have described the results of recent preclinical and clinical studies exploring the pleiotropic effects of curcumin in combination with standard drugs and the potential to consider it as a promising new tool for cancer therapy.

DPHL v.2: An updated and comprehensive DIA pan-human assay library for quantifying more than 14,000 proteins

A comprehensive pan-human spectral library is critical for biomarker discovery using mass spectrometry (MS)-based proteomics. DPHL v.1, a previous pan-human library built from 1,096 data-dependent acquisition (DDA) MS data of 16 human tissue types, allows quantifying of 10,943 proteins. Here, we generated DPHL v.2 from 1,608 DDA-MS data. The data included 586 DDA-MS data acquired from 18 tissue types, while 1,022 files were derived from DPHL v.1. DPHL v.2 thus comprises data from 24 sample types, including several cancer types (lung, breast, kidney, and prostate cancer, among others). We generated four variants of DPHL v.2 to include semi-tryptic peptides and protein isoforms. DPHL v.2 was then applied to two colorectal cancer cohorts. The numbers of identified and significantly dysregulated proteins increased by at least 21.7% and 14.2%, respectively, compared with DPHL v.1. Our findings show that the increased human proteome coverage of DPHL v.2 provides larger pools of potential protein biomarkers.

A hybrid nanopharmaceutical for specific-amplifying oxidative stress to initiate a cascade of catalytic therapy for pancreatic cancer

BACKGROUND

Oxidative stress (OS) induced by an imbalance of oxidants and antioxidants is an important aspect in anticancer therapy, however, as an adaptive response, excessive glutathione (GSH) in the tumor microenvironment (TME) acts as an antioxidant against high reactive oxygen species (ROS) levels and prevents OS damage to maintain redox homoeostasis, suppressing the clinical efficacy of OS-induced anticancer therapies.

RESULTS

A naturally occurring ROS-activating drug, galangin (GAL), is introduced into a Fenton-like catalyst (SiO₂@MnO₂) to form a TME stimulus-responsive hybrid nanopharmaceutical (SiO₂-GAL@MnO₂, denoted SG@M) for enhancing oxidative stress. Once exposed to TME, as MnO₂ responds and consumes GSH, the released Mn²⁺ converts endogenous hydrogen peroxide (H₂O₂) into hydroxyl radicals (·OH), which together with the subsequent release of GAL from SiO₂ increases ROS. The "overwhelming" ROS cause OS-mediated mitochondrial malfunction with a decrease in mitochondrial membrane potential (MMP), which releases cytochrome c from mitochondria, activates the Caspase 9/Caspase 3 apoptotic cascade pathway. Downregulation of JAK2 and STAT3 phosphorylation levels blocks the JAK2/STAT3 cell proliferation pathway, whereas downregulation of Cyclin B1 protein levels arrest the cell cycle in the G2/M phase. During 18 days of in vivo treatment observation, tumor growth inhibition was found to be 62.7%, inhibiting the progression of pancreatic cancer. Additionally, the O₂ and Mn²⁺ released during this cascade catalytic effect improve ultrasound imaging (USI) and magnetic resonance imaging (MRI), respectively.

CONCLUSION

This hybrid nanopharmaceutical based on oxidative stress amplification provides a strategy for multifunctional integrated therapy of malignant tumors and image-visualized pharmaceutical delivery.

Curcumin activates a ROS/KEAP1/NRF2/miR-34a/b/c cascade to suppress colorectal cancer metastasis

Curcumin, a natural phytochemical isolated from tumeric roots, represents a candidate for prevention and therapy of colorectal cancer/CRC. However, the exact mechanism of action and the downstream mediators of curcumin's tumor suppressive effects have remained largely unknown. Here we used a genetic approach to determine the role of the p53/miR-34 pathway as mediator of the effects of curcumin. Three isogenic CRC cell lines rendered deficient for the p53, miR-34a and/or miR-34b/c genes were exposed to curcumin and subjected to cell biological analyses. siRNA-mediated inhibition and ectopic expression of NRF2, as well as Western blot, qPCR and qChIP analyses of its target genes were performed. CRC cells were i.v. injected into NOD/SCID mice and lung-metastases formation was determined by longitudinal, non-invasive imaging. In CRC cells curcumin induced apoptosis and senescence, and suppressed migration and invasion in a p53-independent manner. Curcumin activated the KEAP1/NRF2/ARE pathway by inducing ROS. Notably, curcumin induced miR-34a and miR-34b/c expression in a ROS/NRF2-dependent and p53-independent manner. NRF2 directly induced miR-34a and miR-34b/c via occupying multiple ARE motifs in their promoter regions. Curcumin reverted repression of miR-34a and miR-34b/c induced by IL6 and hypoxia. Deletion of miR-34a and miR-34b/c significantly reduced curcumin-induced apoptosis and senescence, and prevented the inhibition of migration and invasion by curcumin or ectopic NRF2. In CRC cells curcumin induced MET and prevented the formation of lung-metastases in mice in a miR-34a-dependent manner. In addition, we found that curcumin may enhance the therapeutic effects of 5-FU on CRC cells deficient for p53 and miR-34a/b/c. Activation of the KEAP1/NRF2/miR-34a/b/c axis mediates the tumor suppressive activity of curcumin and suggests a new approach for activating miR-34 genes in tumors for therapeutic purposes.

Combination Chemotherapy with Selected Polyphenols in Preclinical and Clinical Studies-An Update Overview

This review article describes studies published over the past five years on the combination of polyphenols, which are the most studied in the field of anticancer effects (curcumin, quercetin, resveratrol, epigallocatechin gallate, and apigenin) and chemotherapeutics such as cisplatin, 5-fluorouracil, oxaliplatin, paclitaxel, etc. According to WHO data, research has been limited to five cancers with the highest morbidity rate (lung, colorectal, liver, gastric, and breast cancer). A systematic review of articles published in the past five years (from January 2018 to January 2023) was carried out with the help of all Web of Science databases and the available base of clinical studies. Based on the preclinical studies presented in this review, polyphenols can enhance drug efficacy and reduce chemoresistance through different molecular mechanisms. Considering the large number of studies, curcumin could be a molecule in future chemotherapy cocktails. One of the main problems in clinical research is related to the limited bioavailability of most polyphenols. The design of a new co-delivery system for drugs and polyphenols is essential for future clinical research. Some polyphenols work in synergy with chemotherapeutic drugs, but some polyphenols can act antagonistically, so caution is always required.

The role of curcumin in the liver-gut system diseases: from mechanisms to clinical therapeutic perspective

Natural products have provided abundant sources of lead compounds for new drug discovery and development over the past centuries. Curcumin is a lipophilic polyphenol isolated from turmeric, a plant used in traditional Asian medicine for centuries. Despite the low oral bioavailability, curcumin exhibits profound medicinal value in various diseases, especially liver and gut diseases, bringing an interest in the paradox of its low bioavailability but high bioactivity. Several latest studies suggest that curcumin's health benefits may rely on its positive gastrointestinal effects rather than its poor bioavailability solely. Microbial antigens, metabolites, and bile acids regulate metabolism and immune responses in the intestine and liver, suggesting the possibility that the liver-gut axis bidirectional crosstalk controls gastrointestinal health and diseases. Accordingly, these pieces of evidence have evoked great interest in the curcumin-mediated crosstalk among liver-gut system diseases. The present study discussed the beneficial effects of curcumin against common liver and gut diseases and explored the underlying molecular targets, as well as collected evidence from human clinical studies. Moreover, this study summarized the roles of curcumin in complex metabolic interactions in liver and intestine diseases supporting the application of curcumin in the liver-gut system as a potential therapeutic option, which opens an avenue for clinical use in the future.

5-Fluorouracil Combined with Rutaecarpine Synergistically Suppresses the Growth of Colon Cancer Cells by Inhibiting STAT3

Purpose

To evaluate the effect of 5-fluorouracil (5-FU) combined with rutaecarpine (RUT) on the antiproliferative, anti-migratory, and apoptosis-promoting ability of colorectal cancer (CRC) cells and explore the underlying mechanism.

Methods

The antiproliferative effects of RUT and 5-FU on CRC cells were evaluated using MTT and colony formation assays. Anti-migration was assessed by cell scratch and transwell tests. The synergistic effect of RUT and 5-FU was assessed by isobologram and combination index analysis using CompuSyn software. The effects of RUT and 5-FU on cell apoptosis were detected by flow cytometry. Differences in protein expression levels with or without RUT and/or 5-FU treatment were assessed by Western blot. Moreover, a mouse xenograft model of CRC was established to investigate the antitumor effect of RUT and 5-FU in vivo, and Ki67 and cleaved caspase-3 expression was detected by immunofluorescence.

Results

In this study, we found that 5-FU combined with RUT can inhibit the proliferative, migratory, and antiapoptotic abilities of CRC cells to a significantly greater extent than either RUT or 5-FU alone both in vivo and in vitro. Western blot analysis showed that the level of signal transducer and activator of transcription 3 (STAT3) phosphorylation in CRC cells was significantly reduced after combination therapy compared with that seen with the respective monotherapies. In addition, combination therapy influenced the STAT3 signaling pathway, namely, it inhibited the expression of c-Myc, CDK4, and Bcl-2 while enhancing that of the proapoptotic protein cleaved caspase-3. Immunofluorescence staining further showed that the expression of Ki67 and cleaved caspase-3 was significantly downregulated and upregulated, respectively, in tumor tissues of mice treated with combination therapy compared with that observed with 5-FU treatment alone.

Conclusion

Combined therapy with 5-FU and RUT exerted a superior curative effect in CRC than treatment with either single drug alone and has potential as a novel therapeutic modality for the treatment of CRC.

Exploiting Polyphenol-Mediated Redox Reorientation in Cancer Therapy

Polyphenol, one of the major components that exert the therapeutic effect of Chinese herbal medicine (CHM), comprises several categories, including flavonoids, phenolic acids, lignans and stilbenes, and has long been studied in oncology due to its significant efficacy against cancers in vitro and in vivo. Recent evidence has linked this antitumor activity to the role of polyphenols in the modulation of redox homeostasis (e.g., pro/antioxidative effect) in cancer cells. Dysregulation of redox homeostasis could lead to the overproduction of reactive oxygen species (ROS), resulting in oxidative stress, which is essential for many aspects of tumors, such as tumorigenesis, progression, and drug resistance. Thus, investigating the ROS-mediated anticancer properties of polyphenols is beneficial for the discovery and development of novel pharmacologic agents. In this review, we summarized these extensively studied polyphenols and discussed the regulatory mechanisms related to the modulation of redox homeostasis that are involved in their antitumor property. In addition, we discussed novel technologies and strategies that could promote the development of CHM-derived polyphenols to improve their versatile anticancer properties, including the development of novel delivery systems, chemical modification, and combination with other agents.

Proteomic analysis of the chemosensitizing effect of curcumin on CRC cells treated with 5-FU

Background

5-Fluorouracil (5-FU) is one of the most common chemotherapy drugs used to treat colorectal cancer (CRC), which often develops resistance in more than 15% of patients. Curcumin, an active component of Curcuma longa, has been reported to show antitumor activity in CRC and, furthermore, enhance the effect of chemotherapy against colorectal cancer cells. However, the molecular mechanisms underlying the sensitizing effect of curcumin on 5-FU have not been largely elucidated. In this study, we aimed to systematically investigate the role of curcumin as a chemosensitizer for the treatment of CRC, along with the key events responsible for its pharmaceutical effect, which may lead to better clinical outcomes.

Methods

A high-resolution 2DE-based proteomics approach was used to characterize global protein expression patterns in CRC cells treated with 5-FU both in combination with curcumin or without. The differentially expressed proteins were obtained from the 2DE analysis and subsequently identified by MALDI-TOF MS or nano-ESI-MS/MS, some of which were validated by the Western blot. Intracellular reactive oxygen species (ROS) were measured to assess the change in the redox environment resulting from the drug treatment.

Results

A series of proteins with altered abundances were detected and identified by MALDI-TOF or nano-MS/MS. From a total of 512 isolated proteins, 22 proteins were found to be upregulated and 6 proteins were downregulated. Intracellular ROS was significantly elevated after curcumin treatment. Furthermore, mass spectrometry data revealed that some of the proteins appeared to have more oxidized forms upon curcumin treatment, suggesting a direct role for ROS in the chemosensitizing effect of curcumin.

Conclusion

The effect of curcumin in enhancing chemosensitivity to 5-FU is a complex phenomenon made up of several mechanisms, including enhancement of the intracellular level of ROS. Our findings presented here could provide clues for a further study aimed at elucidating the mechanisms underlying the chemosensitizing effect of curcumin.

Curcumin: A Novel Way to Improve Quality of Life for Colorectal Cancer Patients?

Colorectal cancer (CRC) is the third most common cancer in men and the second most common in women. Treatment of metastatic CRC consists of highly toxic chemotherapeutic drug combinations that often negatively affect patient quality of life (QoL). Moreover, chemotherapy-induced toxicity and chemotherapy resistance are among the most important factors limiting cancer treatment and can lead to the interruption or discontinuation of potentially effective therapy. Several preclinical studies have demonstrated that curcumin acts through multiple cellular pathways and possesses both anti-cancer properties against CRC and the capacity to mitigate chemotherapy-related side effects and overcome drug resistance. In this review article, we suggest that the addition of curcumin to the standard chemotherapeutic treatment for metastatic CRC could reduce associated side-effects and overcome chemotherapy resistance, thereby improving patient QoL.

Curcumin in the treatment of urological cancers: Therapeutic targets, challenges and prospects

Urological cancers include bladder, prostate and renal cancers that can cause death in males and females. Patients with urological cancers are mainly diagnosed at an advanced disease stage when they also develop resistance to therapy or poor response. The use of natural products in the treatment of urological cancers has shown a significant increase. Curcumin has been widely used in cancer treatment due to its ability to trigger cell death and suppress metastasis. The beneficial effects of curcumin in the treatment of urological cancers is the focus of current review. Curcumin can induce apoptosis in the three types of urological cancers limiting their proliferative potential. Furthermore, curcumin can suppress invasion of urological cancers through EMT inhibition. Notably, curcumin decreases the expression of MMPs, therefore interfering with urological cancer metastasis. When used in combination with chemotherapy agents, curcumin displays synergistic effects in suppressing cancer progression. It can also be used as a chemosensitizer. Based on pre-clinical studies, curcumin administration is beneficial in the treatment of urological cancers and future clinical applications might be considered upon solving problems related to the poor bioavailability of the compound. To improve the bioavailability of curcumin and increase its therapeutic index in urological cancer suppression, nanostructures have been developed to favor targeted delivery.

Inhibition and potential treatment of colorectal cancer by natural compounds via various signaling pathways

Colorectal cancer (CRC) is a common type of malignant digestive tract tumor with a high incidence rate worldwide. Currently, the clinical treatment of CRC predominantly include surgical resection, postoperative chemotherapy, and radiotherapy. However, these treatments contain severe limitations such as drug side effects, the risk of recurrence and drug resistance. Some natural compounds found in plants, fungi, marine animals, and bacteria have been shown to inhibit the occurrence and development of CRC. Although the explicit molecular mechanisms underlying the therapeutic effects of these compounds on CRC are not clear, classical signaling transduction pathways such as NF-kB and Wnt/β-catenin are extensively regulated. In this review, we have summarized the specific mechanisms regulating the inhibition and development of CRC by various types of natural compounds through nine signaling pathways, and explored the potential therapeutic values of these natural compounds in the clinical treatment of CRC.

Curcumin against gastrointestinal cancer: A review of the pharmacological mechanisms underlying its antitumor activity

Gastrointestinal cancer (GIC) poses a serious threat to human health globally. Curcumin (CUR), a hydrophobic polyphenol extracted from the rhizome of Curcuma longa, has shown reliable anticancer function and low toxicity, thereby offering broad research prospects. Numerous studies have demonstrated the pharmacological mechanisms underlying the effectiveness of CUR against GIC, including the induction of apoptosis and autophagy, arrest of the cell cycle, inhibition of the epithelial–mesenchymal transition (EMT) processes, inhibition of cell invasion and migration, regulation of multiple signaling pathways, sensitization to chemotherapy and reversal of resistance to such treatments, and regulation of the tumor survival environment. It has been confirmed that CUR exerts its antitumor effects on GIC through these mechanisms in vitro and in vivo. Moreover, treatment with CUR is safe and tolerable. Newly discovered types of regulated cell death (RCD), such as pyroptosis, necroptosis, and ferroptosis, may provide a new direction for research on the efficacy of CUR against GIC. In this review, we discuss the recently found pharmacological mechanisms underlying the effects of CUR against GIC (gastric and colorectal cancers). The objective is to provide a reference for further research on treatments against GIC.

Nicotinamide N-Methyltransferase as Promising Tool for Management of Gastrointestinal Neoplasms

Gastrointestinal (GI) neoplasms include esophageal, gastric, colorectal, hepatic, and pancreatic cancers. They are characterized by asymptomatic behavior, being responsible for diagnostic delay. Substantial refractoriness to chemo- and radiotherapy, exhibited by late-stage tumors, contribute to determine poor patient outcome. Therefore, it is of outmost importance to identify new molecular targets for the development of effective therapeutic strategies. In this study, we focused on the enzyme nicotinamide N-methyltransferase (NNMT), which catalyzes the N-methylation reaction of nicotinamide and whose overexpression has been reported in numerous neoplasms, including GI cancers. The aim of this review was to report data illustrating NNMT involvement in these tumors, highlighting its contribution to tumor cell phenotype. Cited works clearly demonstrate the interesting potential use of enzyme level determination for both diagnostic and prognostic purposes. NNMT was also found to positively affect cell viability, proliferation, migration, and invasiveness, contributing to sustain in vitro and in vivo tumor growth and metastatic spread. Moreover, enzyme upregulation featuring tumor cells was significantly associated with enhancement of resistance to treatment with chemotherapeutic drugs. Taken together, these results strongly suggest the possibility to target NNMT for setup of molecular-based strategies to effectively treat GI cancers.

The Synergistic Effects of Curcumin and Chemotherapeutic Drugs in Inhibiting Metastatic, Invasive and Proliferative Pathways

Curcumin, the main phytochemical identified from the Curcuma longa L. family, is one of the spices used in alternative medicine worldwide. It has exhibited a broad range of pharmacological activities as well as promising effects in the treatment of multiple cancer types. Moreover, it has enhanced the activity of other chemotherapeutic drugs and radiotherapy by promoting synergistic effects in the regulation of various cancerous pathways. Despite all the literature addressing the molecular mechanism of curcumin on various cancers, no review has specifically addressed the molecular mechanism underlying the effect of curcumin in combination with therapeutic drugs on cancer metastasis. The current review assesses the synergistic effects of curcumin with multiple drugs and light radiation, from a molecular perspective, in the inhibition of metastasis, invasion and proliferation. A systemic review of articles published during the past five years was performed using MEDLINE/PubMed and Scopus. The assessment of these articles evidenced that the combination therapy with various drugs, including doxorubicin, 5-fluorouracil, paclitaxel, berberine, docetaxel, metformin, gemcitabine and light radiation therapy on various types of cancer, is capable of ameliorating different metastatic pathways that are presented and evaluated. However, due to the heterogeneity of pathways and proteins in different cell lines, more research is needed to confirm the root causes of these pathways.

Effects and Mechanisms of Curcumin for the Prevention and Management of Cancers: An Updated Review

Cancer is the leading cause of death in the world. Curcumin is the main ingredient in turmeric (Curcuma longa L.), and is widely used in the food industry. It shows anticancer properties on different types of cancers, and the underlying mechanisms of action include inhibiting cell proliferation, suppressing invasion and migration, promoting cell apoptosis, inducing autophagy, decreasing cancer stemness, increasing reactive oxygen species production, reducing inflammation, triggering ferroptosis, regulating gut microbiota, and adjuvant therapy. In addition, the anticancer action of curcumin is demonstrated in clinical trials. Moreover, the poor water solubility and low bioavailability of curcumin can be improved by a variety of nanotechnologies, which will promote its clinical effects. Furthermore, although curcumin shows some adverse effects, such as diarrhea and nausea, it is generally safe and tolerable. This paper is an updated review of the prevention and management of cancers by curcumin with a special attention to its mechanisms of action.

Overexpression of NNMT in Glioma Aggravates Tumor Cell Progression: An Emerging Therapeutic Target

Simple Summary

Glioma is one of the most common intracranial malignancies and is incurable due to strong aggressiveness and resistance to radiotherapy and chemotherapy. The lack of effective therapeutic targets is a major problem in current treatment. In the present study, we found that nicotinamide N-methyltransferase (NNMT) is a key factor influencing the occurrence and development of glioma. High NNMT expression in glioma is a predictor of short overall survival and poor patient outcome. NNMT knockdown reduced the volume of mice xenograft glioma and the viability of glioma cells. Additionally, overexpression of NNMT epigenetically silenced GAP43 through DNA methylation, histone methylation, and deacetylation modification processes. GAP43 can inhibit the formation of microtubules in tumor and intertumor cell network connections and induce apoptosis through the SIRT1 signaling pathway. Therefore, NNMT could be a potential candidate for the clinical diagnosis and treatment of glioma.

Abstract

Purpose: Increasing evidence has revealed that nicotinamide N-methyltransferase (NNMT) is a key factor influencing the prognosis of tumors. The present study aimed to investigate the role of NNMT in glioma and to elucidate the associated functional mechanisms. Methods: Clinical samples were analyzed by immunohistochemical staining and Western blotting to evaluate NNMT expression in glioma and normal brain tissues. The correlation between NNMT expression and glioma was analyzed using the Cancer Genome Atlas (TCGA) database. Additionally, NNMT was knocked down in two types of glioma cells, U87 and U251, to evaluate the invasive ability of these cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate NNMT knockdown in the cells. Furthermore, ELISA was used to determine the balance between nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide hydrogen (NAD/NADH ratio), which verified the altered methylation patterns in the cells. The glioma xenograft mouse models were used to verify the regulatory role of NNMT, GAP43, and SIRT1. Results: Analysis based on our clinical glioma samples and TCGA database revealed that overexpression of NNMT was associated with poor prognosis of patients. Knockdown of NNMT reduced the invasive ability of glioma cells, and downregulation of its downstream protein GAP43 occurred due to altered cellular methylation caused by NNMT overexpression. Gene Set Enrichment Analysis confirmed that NNMT modulated the NAD-related signaling pathway and showed a negative association between NNMT and SIRT1. Moreover, the regulatory roles of NNMT, GAP43, and SIRT1 were confirmed in glioma xenograft mouse models. Conclusion: Overexpression of NNMT causes abnormal DNA methylation through regulation of the NAD/NADH ratio, which in turn leads to the downregulation of GAP43 and SIRT1, eventually altering the biological behavior of tumor cells.

Selective delivery of curcumin to breast cancer cells by self-targeting apoferritin nanocages with pH-responsive and low toxicity

Breast cancer is prevalent and diverse with significantly high incidence and mortality rates. Curcumin (Cur), a polyphenol component of turmeric, has been widely recognized as having strong anti-breast cancer activity. However, its anti-cancer efficiency is largely impaired by some of its concomitant negative properties, including its poor solubility, low cellular uptake, and severe reported side effects. Hence, the necessity arises to develop a novel low-toxic and high-efficiency targeting drug delivery system (DDS). In this study, we developed a pH-sensitive tumor self-targeting DDS (Cur@HFn) based on self-assembled HFn loaded with Cur, in which Cur was encapsulated into HFn cavity by using a disassembly/reassembly strategy, and the Cur@HFn was characterized by ultraviolet–visible (UV–vis), dynamic light scattering (DLS), and transmission electron microscope (TEM). A variety of breast cancer cell models were built to evaluate cytotoxicity, apoptosis, targeting properties, and uptake mechanism of the Cur@HFn. The pharmacodynamics was also evaluated in tumor (4T1) bearing mice after intravenous injection. In vitro release experiments showed that Cur@HFn is pH sensitive and shows sustained drug release under slightly acidic conditions. Compared with Cur, Cur@HFn has stronger cytotoxicity, cellular uptake, and targeting performance. Our study supported that Cur@HFn has a higher in vivo therapeutic effect and lower systemic toxicity. The safety evaluation results indicated that Cur@HFn has no hematotoxicity, hepatotoxicity, and nephrotoxicity. The findings of the present study showed that the Cur@HFn has been successfully prepared and has potential application value in the treatment of breast cancer.