Curcumin inhibits tumor epithelial‑mesenchymal transition by downregulating the Wnt signaling pathway and upregulating NKD2 expression in colon cancer cells

Curcumin suppresses the Wnt/β-catenin signaling pathway by inhibiting NKD2 methylation to ameliorate intestinal ischemia/reperfusion injury

Intestinal ischemia/reperfusion (I/R) injury is a life-threatening condition with no effective treatment currently available. Curcumin (CCM), a polyphenol compound in Curcuma Longa, reportedly has positive effects against intestinal I/R injury. However, the mechanism underlying the protective effect of CCM against intestinal I/R injury has not been fully clarified. To determine whether the protective effect of CCM was mediated by epigenetic effects on Wnt/β-catenin signaling, the effect of CCM was examined in vivo and in vitro. An intestinal I/R model was established in Sprague-Dawley (SD) rats with superior mesenteric artery occlusion, and Caco-2 cells were subjected to hypoxia/reoxygenation (H/R) for in vivo simulation of I/R. The results showed that CCM significantly reduced inflammatory, cell apoptosis, and oxidative stress induced by I/R insult in vivo and in vitro. Western blot analysis showed that CCM preconditioning reduced the protein levels of β-catenin, p-GSK3β, and cyclin-D1 and increased the protein level of GSK3β compared with the I/R group. Overexpressing β-catenin aggravated H/R injury, and knocking down β-catenin relieved H/R injury by improving intestinal permeability and reducing the cell apoptosis. Moreover, Naked cuticle homolog 2(NKD2) mRNA and protein levels were upregulated in the CCM-pretreated group. 5-aza-2'-deoxycytidine (5-AZA) treatment improved intestinal epithelial barrier impairment induced by H/R. Besides, the protein levels of total β-catenin, phosphor-β-catenin and cyclin-D1 were reduced after overexpressing NKD2 in Caco-2 cells following H/R insult. In conclusion, Our study suggests that CCM could attenuate intestinal I/R injury in vitro and in vivo by suppressing the Wnt/β-catenin signaling pathway via inhibition of NKD2 methylation.

Transcriptomic and proteomic analysis of tumor suppressive effects of GZ17-6.02 against mycosis fungoides

Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma (CTCL). Despite having a wide variety of therapeutic agents available for the treatment of MF, patients often suffer from a significant decrease in quality of life and rarely achieve long-term remission or complete cure, highlighting a need to develop novel therapeutic agents for this disease. The present study was undertaken to evaluate the efficacy of a novel anti-tumor agent, GZ17-6.02, which is composed of curcumin, harmine, and isovanillin, against MF in vitro and in murine models. Treatment of HH and MyLa cells with GZ17-6.02 inhibited the growth of both cell lines with IC50 ± standard errors for growth inhibition of 14.37 ± 1.19 µg/mL and 14.56 ± 1.35 µg/mL, respectively, and increased the percentage of cells in late apoptosis (p = .0304 for HH; p = .0301 for MyLa). Transcriptomic and proteomic analyses revealed that GZ17-6.02 suppressed several pathways, including tumor necrosis factor (TNF)-ɑ signaling via nuclear factor (NF)-kB, mammalian target of rapamycin complex (mTORC)1, and Pi3K/Akt/mTOR signaling. In a subcutaneous tumor model, GZ17-6.02 decreased tumor volume (p = .002) and weight (p = .009) compared to control conditions. Proteomic analysis of tumor samples showed that GZ17-6.02 suppressed the expression of several proteins that may promote CTCL growth, including mitogen-activated protein kinase (MAPK)1, MAPK3, Growth factor receptor bound protein (GRB)2, and Mediator of RAP80 interactions and targeting subunit of 40 kDa (MERIT)40.

Curcumin Disrupts a Positive Feedback Loop between ADMSCs and Cancer Cells in the Breast Tumor Microenvironment via the CXCL12/CXCR4 Axis

Adipose tissue has a significant impact on breast cancer initiation and progression owing to its substantial proportion in the breast. Adipose-derived mesenchymal stem cells (ADMSCs) are major players in the breast tumor microenvironment (TME) as they interact with cancer cells. The intricate interaction between ADMSCs and cancer cells not only drives the differentiation of ADMSCs into cancer-associated fibroblasts (CAFs) but also the metastasis of cancer cells, which is attributed to the CXCL12/CXCR4 axis. We investigated the effects of curcumin, a flavonoid known for CXCL12/CXCR4 axis inhibition, on breast TME by analyzing whether it can disrupt the ADMSC-cancer positive loop. Using MCF7 breast cancer cell-derived conditioned medium (MCF7-CM), we induced ADMSC transformation and verified that curcumin diminished the phenotypic change, inhibiting CAF marker expression. Additionally, curcumin suppressed the CXCL12/CXCR4 axis and its downstream signaling both in ADMSCs and MCF7 cells. The CM from ADMSCs, whose ADMSC-to-CAF transformation was repressed by the curcumin treatment, inhibited the positive feedback loop between ADMSCs and MCF7 as well as epithelial-mesenchymal transition in MCF7. Our study showed that curcumin is a potent anti-cancer agent that can remodel the breast TME, thereby restricting the ADMSC-cancer positive feedback loop associated with the CXCL12/CXCR4 axis.

Curcumin and chemokines: mechanism of action and therapeutic potential in inflammatory diseases

Chemokines belong to the family of cytokines with chemoattractant properties that regulate chemotaxis and leukocyte migration, as well as the induction of angiogenesis and maintenance of hemostasis. Curcumin, the major component of the Curcuma longa rhizome, has various pharmacological actions, including anti-inflammatory, immune-regulatory, anti-oxidative, and lipid-modifying properties. Chemokines and chemokine receptors are influenced/modulated by curcumin. Thus, the current review focuses on the molecular mechanisms associated with curcumin's effects on chemoattractant cytokines, as well as putting into context the many studies that have reported curcumin-mediated regulatory effects on inflammatory conditions in the organs/systems of the body (e.g., the central nervous system, liver, and cardiovascular system). Curcumin's effects on viral and bacterial infections, cancer, and adverse pregnancy outcomes are also reviewed.

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

A systems biology investigation of curcumin potency against TGF-β-induced EMT signaling in lung cancer

Curcumin (diferuloylmethane) is bioactive phenolic compound which exerts diverse antimetastatic effect. Several studies have reported the antimetastatic effect of curcumin by its ability to modulate the epithelial-to-mesenchymal transition (EMT) process in different cancers, but underlying molecular mechanism is poorly understood. EMT is a highly conserved biological process in which epithelial cells acquire mesenchymal-like characteristics by losing their cell-cell junctions and polarity. As a consequence, deviation in cellular mechanism leads to cancer metastasis and thereby death. In this perspective, we explored the antimetastatic potential and mechanism of curcumin on the EMT process by establishing in vitro EMT model in lungs cancer (A549) cells induced by TGF-β1. Our results showed that curcumin mitigates EMT by regulating the expression of crucial mesenchymal markers such as MMP2, vimentin and N-cadherin. Besides, the transcriptional analysis revealed that the curcumin treatment differentially regulated the expression of 75 genes in NanoString nCounter platform. Further protein-protein interaction network and clusters analysis of differentially expressed genes revealed their involvement in essential biological processes that plays a key role during EMT transition. Altogether, the study provides a comprehensive overview of the antimetastatic potential of curcumin in TGF-β1-induced EMT in lung cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03360-7.

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.

Therapeutic approaches to colorectal cancer via strategies based on modulation of gut microbiota

Colorectal cancer (CRC) ranks third in terms of global incidence and second in terms of death toll among malignant tumors. Gut microbiota are involved in the formation, development, and responses to different treatments of CRC. Under normal physiological conditions, intestinal microorganisms protect the intestinal mucosa, resist pathogen invasion, and regulate the proliferation of intestinal mucosal cells via a barrier effect and inhibition of DNA damage. The composition of gut microbiota and the influences of diet, drugs, and gender on the composition of the intestinal flora are important factors in the early detection of CRC and prediction of the results of CRC treatment. Regulation of gut microbiota is one of the most promising new strategies for CRC treatment, and it is essential to clarify the effect of gut microbiota on CRC and its possible mechanisms to facilitate the prevention and treatment of CRC. This review discusses the role of gut microbiota in the pathogenesis of CRC, the potential of gut microbiota as biomarkers for CRC, and therapeutic approaches to CRC based on the regulation of gut microbiota. It might provide new ideas for the use of gut microbiota in the prevention and treatment of CRC in the near future and thus reduce the incidence of CRC.

The Tumor Suppressor Roles and Mechanisms of MiR-491 in Human Cancers

MicroRNAs (miRNAs) are short non-coding RNAs that bind to the 3' untranslated region (3'' UTR) of target mRNAs to control gene expression post-transcriptionally. Recent indications have highlighted their important roles in a variety of pathophysiological conditions as well as human malignancies. Dysregulated miRNAs act as tumor suppressor genes or oncogenes in a variety of cancers. MiR-491 has been shown to have a major effect on tumorigenesis in multiple malignancies through binding to specific genes and signaling cascades, thereby preventing cancer progression. This review provides an overview of miR-491 expression in regulatory mechanisms and biological procedures of tumor cells, as well as the prospective possible treatment effects of various types of human cancers.

Traditional Chinese Medicines as Effective Reversals of Epithelial-Mesenchymal Transition Induced-Metastasis of Colorectal Cancer: Molecular Targets and Mechanisms

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Distant metastasis is the major cause of cancer-related mortality in patients with CRC. Epithelial-mesenchymal transition (EMT) is a critical process triggered during tumor metastasis, which is also the main impetus and the essential access within this duration. Therefore, targeting EMT-related molecular pathways has been considered a novel strategy to explore effective therapeutic agents against metastatic CRC. Traditional Chinese medicines (TCMs) with unique properties multi-target and multi-link that exert their therapeutic efficacies holistically, which could inhibit the invasion and metastasis ability of CRC cells via inhibiting the EMT process by down-regulating transforming growth factor-β (TGF-β)/Smads, PI3K/Akt, NF-κB, Wnt/β-catenin, and Notch signaling pathways. The objective of this review is to summarize and assess the anti-metastatic effect of TCM-originated bioactive compounds and Chinese medicine formulas by mediating EMT-associated signaling pathways in CRC therapy, providing a foundation for further research on the exact mechanisms of action through which TCMs affect EMT transform in CRC.

Therapeutic Potential of Naturally Occurring Small Molecules to Target the Wnt/β-Catenin Signaling Pathway in Colorectal Cancer

Simple Summary

Colorectal cancer (CRC) is an emerging public health problem and the second leading cause of death worldwide, with a significant socioeconomic impact in several countries. The 5-year survival rate is only 12% due to the lack of early diagnosis and resistance to available treatments, and the canonical Wnt signaling pathway is involved in this process. This review underlines the importance of understanding the fundamental roles of this pathway in physiological and pathological contexts and analyzes the use of naturally occurring small molecules that inhibits the Wnt/β-catenin pathway in experimental models of CRC. We also discuss the progress and challenges of moving these small molecules off the laboratory bench into the clinical platform.

Abstract

Colorectal cancer (CRC) ranks second in the number of cancer deaths worldwide, mainly due to late diagnoses, which restrict treatment in the potentially curable stages and decrease patient survival. The treatment of CRC involves surgery to remove the tumor tissue, in addition to radiotherapy and systemic chemotherapy sessions. However, almost half of patients are resistant to these treatments, especially in metastatic cases, where the 5-year survival rate is only 12%. This factor may be related to the intratumoral heterogeneity, tumor microenvironment (TME), and the presence of cancer stem cells (CSCs), which is impossible to resolve with the standard approaches currently available in clinical practice. CSCs are APC-deficient, and the search for alternative therapeutic agents such as small molecules from natural sources is a promising strategy, as these substances have several antitumor properties. Many of those interfere with the regulation of signaling pathways at the central core of CRC development, such as the Wnt/β-catenin, which plays a crucial role in the cell proliferation and stemness in the tumor. This review will discuss the use of naturally occurring small molecules inhibiting the Wnt/β-catenin pathway in experimental CRC models over the past decade, highlighting the molecular targets in the Wnt/β-catenin pathway and the mechanisms through which these molecules perform their antitumor activities.

The Role of Chemokines in Cardiovascular Diseases and the Therapeutic Effect of Curcumin on CXCL8 and CCL2 as Pathological Chemokines in Atherosclerosis

Curcumin, as a vegetative flavonoid, has a protective and therapeutic role in various adverse states such as oxidative stress and inflammation. Remedial properties of this component have been reported in the different chronic diseases including cancers (myeloma, pancreatic, breast, colorectal), vitiligo, psoriasis, neuropathic pains, inflammatory disorders (osteoarthritis, uveitis, ulcerative colitis, Alzheimer), cardiovascular conditions, and diabetes.Cardiovascular disorders include atherosclerosis and various manifestations of atherosclerosis such as stroke, and myocardial infarction (MI) is the leading cause of mortality globally. Studies have shown varying expressions of inflammatory and non-inflammatory chemokines and chemokine receptors in cardiovascular disease, which have been highlighted first in this review. The alteration in chemokines secretion and chemokine receptors has an essential role in the pathophysiology of cardiovascular disease. Chemokines as cytokines with low molecular weight (8-12 kDa) mediate white blood cell (WBC) chemotactic reactions, vascular cell migration, and proliferation that induce endothelial dysfunction, atherogenesis, and cardiac hypertrophy.Several studies reported that curcumin could be advantageous in the attenuation of cardiovascular diseases via anti-inflammatory effects and redress of chemokine secretion and chemokine receptors. We present these studies with a focus on two chemokines: CXCL8 (IL-8) and CCL2 (chemoattractant protein 1 or MCP-1). Future research will further elucidate the precise potential of curcumin on chemokines in the adjustment of cardiovascular system activity or curcumin chemokine-based therapies.

Flavonoids: Classification, Function, and Molecular Mechanisms Involved in Bone Remodelling

Flavonoids are polyphenolic compounds spotted in various fruits, vegetables, barks, tea plants, and stems and many more natural commodities. They have a multitude of applications through their anti-inflammatory, anti-oxidative, anti-carcinogenic properties, along with the ability to assist in the stimulation of bone formation. Bone, a rigid connective body tissue made up of cells embedded in a mineralised matrix is maintained by an assemblage of pathways assisting osteoblastogenesis and osteoclastogenesis. These have a significant impact on a plethora of bone diseases. The homeostasis between osteoblast and osteoclast formation decides the integrity and structure of the bone. The flavonoids discussed here are quercetin, kaempferol, icariin, myricetin, naringin, daidzein, luteolin, genistein, hesperidin, apigenin and several other flavonoids. The effects these flavonoids have on the mitogen activated protein kinase (MAPK), nuclear factor kappa β (NF-kβ), Wnt/β-catenin and bone morphogenetic protein 2/SMAD (BMP2/SMAD) signalling pathways, and apoptotic pathways lead to impacts on bone remodelling. In addition, these polyphenols regulate angiogenesis, decrease the levels of inflammatory cytokines and play a crucial role in scavenging reactive oxygen species (ROS). Considering these important effects of flavonoids, they may be regarded as a promising agent in treating bone-related ailments in the future.

Microarray profile analysis identifies ETS1 as potential biomarker regulated by miR-23b and modulates TCF4 in gastric cancer

Background

Gastric cancer (GC), a common malignancy of the human digestive system, represents the second leading cause of cancer-related deaths worldwide. Early detection of GC has a significant impact on clinical outcomes. The aim of this study was to identify potential GC biomarkers.

Methods

In this study, we conducted a multi-step analysis of expression profiles in GC clinical samples downloaded from TCGA database to identify differentially expressed miRNAs (DEMs) and differentially expressed mRNAs (DEGs). Potential prognostic biomarkers from the available DEMs were then established using the Cox regression method. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to investigate the biological role of the predicted target genes of the miRNA biomarkers. Then, the prognostic DEM-mediated regulatory network was constructed based on transcription factor (TF)–miRNA–target interaction. Subsequently, the consensus genes were further determined based on the overlap between DEGs and these target genes of DEMs. Besides, expression profile, co-expression analysis, immunity, and prognostic values of these prognostic genes were also investigated to further explore the roles in the mechanism of GC tumorigenesis.

Results

We got five miRNAs, including miR-23b, miR-100, miR-143, miR-145, and miR-409, which are associated with the overall survival of GC patients. Subsequently, enrichment analysis of the target genes of the miRNA biomarkers shown that the GO biological process terms were mainly enriched in mRNA catabolic process, nuclear chromatin, and RNA binding. In addition, the KEGG pathways were significantly enriched in fatty acid metabolism, extracellular matrix (ECM) receptor interaction, and proteoglycans in cancer pathways. The transcriptional regulatory network consisting of 68 TFs, 4 DEMs, and 58 targets was constructed based on the interaction of TFs, miRNAs, and targets. The downstream gene ETS1 of miR-23b and TCF4 regulated by ETS1 were obtained by the regulatory network construction and co-expression analysis. High expression of ETS1 and TCF4 indicated poor prognosis in GC patients, particularly in the advanced stages. The expression of ETS1 and TCF4 was correlated with CD4⁺ T cells, CD8⁺ T cells, and B cells.

Conclusions

miR-23b, ETS1, and TCF4 were identified as the prognostic biomarkers. ETS1 and TCF4 had potential immune function in GC, which provided a theoretical basis for molecular-targeted combined immunotherapy in the future.

Therapeutic Effects of Polyphenols on the Treatment of Colorectal Cancer by Regulating Wnt β-Catenin Signaling Pathway

Colorectal cancer (CRC) is the third most common cause of cancer-related death worldwide in terms of both its rates of incidence and mortality. Due to serious side effects associated with conventional chemotherapeutic treatments, many natural products with fewer adverse side effects have been considered as potential treatment options. In fact, many natural products have widely been used in various phases of clinical trials for CRC, as well as in in vitro and in vivo preclinical studies. Curcumin (CUR) and resveratrol (RES) are classified as natural polyphenolic compounds that have been demonstrated to have anticancer activity against CRC and are associated with minimal side effects. By regulating select target genes involved in several key signaling pathways in CRC, in particular, the Wnt β-catenin signaling cascade, the course of CRC may be positively altered. In the current review, we focused on the therapeutic effects of CUR and RES in CRC as they pertain to modulation of the Wnt β-catenin signaling pathway.

Antimetastatic Effects of Curcumin in Oral and Gastrointestinal Cancers

Gastrointestinal (GI) cancers are known as frequently occurred solid malignant tumors that can cause the high rate mortality in the world. Metastasis is a significant destructive feature of tumoral cells, which directly correlates with decreased prognosis and survival. Curcumin, which is found in turmeric, has been identified as a potent therapeutic natural bioactive compound (Curcuma longa). It has been traditionally applied for centuries to treat different diseases, and it has shown efficacy for its anticancer properties. Numerous studies have revealed that curcumin inhibits migration and metastasis of GI cancer cells by modulating various genes and proteins, i.e., growth factors, inflammatory cytokines and their receptors, different types of enzymes, caspases, cell adhesion molecules, and cell cycle proteins. Herein, we summarized the antimetastatic effects of curcumin in GI cancers, including pancreatic cancer, gastric cancer, colorectal cancer, oral cancer, and esophageal cancer.

Curcumin in combination with homoharringtonine suppresses lymphoma cell growth by inhibiting the TGF-β/Smad3 signaling pathway

Both homoharringtonine (HHT) and curcumin exhibit anti-proliferative effects on lymphoma cells, but the effects of combined HHT and curcumin treatment remain unclear. Here, we investigated the effects of HHT/curcumin combination on the proliferation, apoptosis, and invasion in lymphoma cells. CCK-8, flow cytometry, and transwell assays were used to assess proliferation, apoptosis, and invasion of U937 and Raji cells. p-Smad3, E-cadherin, and N-cadherin expression were also measured in Raji cells using Western blot assays. Combination of HHT and curcumin synergistically inhibited U937 and Raji cell proliferation and invasion. In addition, the combination treatment markedly increased apoptosis of Raji cells as evidenced by increased Bax, cleaved caspase 3, and cleaved caspase 9 expression. Meanwhile, the combination treatment promoted anti-tumor mechanisms in Raji cells as indicated by decreases in p-Smad3 and N-cadherin and increases in E-cadherin. In vivo experiments showed that the combination treatment suppressed tumor growth in a mouse Raji xenograft model. Our findings indicate that combination of HHT and curcumin inhibited lymphoma cell growth by downregulating the TGF-β/Smad3 pathway. These results suggest that HHT combined with curcumin might be a promising therapeutic approach for the treatment of lymphoma.

Traditional Chinese Medicine and Colorectal Cancer: Implications for Drug Discovery

As an important part of complementary and alternative medicine, traditional Chinese medicine (TCM) has been applied to treat a host of diseases for centuries. Over the years, with the incidence rate of human colorectal cancer (CRC) increasing continuously and the advantage of TCM gradually becoming more prominent, the importance of TCM in both domestic and international fields is also growing with each passing day. However, the unknowability of active ingredients, effective substances, and the underlying mechanisms of TCM against this malignant tumor greatly restricts the translation degree of clinical products and the pace of precision medicine. In this review, based on the characteristics of TCM and the oral administration of most ingredients, we herein provide beneficial information for the clinical utilization of TCM in the prevention and treatment of CRC and retrospect the current preclinical studies on the related active ingredients, as well as put forward the research mode for the discovery of active ingredients and effective substances in TCM, to provide novel insights into the research and development of innovative agents from this conventional medicine for CRC treatment and assist the realization of precision medicine.

Therapeutic effect of curcumin in gastrointestinal cancers: A comprehensive review

Gastrointestinal (GI) cancers with a high global prevalence are a leading cause of morbidity and mortality. Accordingly, there is a great need to develop efficient therapeutic approaches. Curcumin, a naturally occurring agent, is a promising compound with documented safety and anticancer activities. Recent studies have demonstrated the activity of curcumin in the prevention and treatment of different cancers. According to systematic studies on curcumin use in various diseases, it can be particularly effective in GI cancers because of its high bioavailability in the gastrointestinal tract. Nevertheless, the clinical applications of curcumin are largely limited because of its low solubility and low chemical stability in water. These limitations may be addressed by the use of relevant analogues or novel delivery systems. Herein, we summarize the pharmacological effects of curcumin against GI cancers. Moreover, we highlight the application of curcumin's analogues and novel delivery systems in the treatment of GI cancers.

Targeting the crosstalk between canonical Wnt/β-catenin and inflammatory signaling cascades: A novel strategy for cancer prevention and therapy

Emerging scientific evidence indicates that inflammation is a critical component of tumor promotion and progression. Most cancers originate from sites of chronic irritation, infections and inflammation, underscoring that the tumor microenvironment is largely orchestrated by inflammatory cells and pro-inflammatory molecules. These inflammatory components are intimately involved in neoplastic processes which foster proliferation, survival, invasion, and migration, making inflammation the primary target for cancer prevention and treatment. The influence of inflammation and the immune system on the progression and development of cancer has recently gained immense interest. The Wnt/β-catenin signaling pathway, an evolutionarily conserved signaling strategy, has a critical role in regulating tissue development. It has been implicated as a major player in cancer development and progression with its regulatory role on inflammatory cascades. Many naturally-occurring and small synthetic molecules endowed with inherent anti-inflammatory properties inhibit this aberrant signaling pathway, making them a promising class of compounds in the fight against inflammatory cancers. This article analyzes available scientific evidence and suggests a crosslink between Wnt/β-catenin signaling and inflammatory pathways in inflammatory cancers, especially breast, gastrointestinal, endometrial, and ovarian cancer. We also highlight emerging experimental findings that numerous anti-inflammatory synthetic and natural compounds target the crosslink between Wnt/β-catenin pathway and inflammatory cascades to achieve cancer prevention and intervention. Current challenges, limitations, and future directions of research are also discussed.

Expression and prognostic significance of NKD2 in ovarian cancer

PURPOSE

Naked2 (NKD2) is a negative regulator of Wnt signaling pathway and associates with transforming growth factor secretion. The role of NKD2 in ovarian cancer is unknown.

PATIENTS AND METHODS

Gene expression profiles were measured and compared in nine patients by RNA sequencing. NKD2 expressions in ovarian cancer were measured by reverse transcription polymerase chain reaction and western blot. Tissue slides of 79 patients were stained and scored for NKD2 expression. In vitro experiments were conducted to explore the role of NKD2 in ovarian cancer. The prognostic role of NKD2 was evaluated by survival analysis.

RESULTS

NKD2 was upregulated in patients with better survival by mRNA and protein expression. Patients were classified as NKD2-high group (n = 30) and NKD2-low group (n = 49) according to immunohistochemical score. High NKD2 was correlated with lower recurrence rate (P = 0.002) and higher percentage of platinum-sensitive recurrence (P = 0.006). Median progression-free survival was significantly longer for NKD2-high patients than NKD2-low patients (49.1 vs.14.1 months, P < 0.001). Accordingly, there was a significantly difference in terms of overall survival time between two groups (hazard ratio: 3.04; 95% confidence interval: 1.58-5.85, P < 0.001). Multivariate regression suggested that NKD2 was independently prognostic factors in terms of progression-free survival (hazard ratio: 2.91; 95% confidence interval: 1.61-5.27, P < 0.001) and overall survival (hazard ratio: 3.6; 95% confidence interval: 1.80-7.21, P < 0.001). In vitro studies further demonstrated that NKD2 suppressed ovarian cancer cell proliferation, colony formation and cell migration.

CONCLUSION

NKD2 is a novel prognostic marker and could suppress tumor progression in ovarian cancer.

Modulation of the Canonical Wnt Signaling Pathway by Dietary Polyphenols, an Opportunity for Colorectal Cancer Chemoprevention and Treatment

In the last few decades there has been a rise in the worldwide incidence of colorectal cancer which can be traced back to the influence of well-known modifiable risk factors such as lifestyle, diet and obesity. Conversely, the consumption of fruits, vegetables and fiber decreases the risk of CRC, which is why dietary polyphenols have aroused interest in recent years as potentially anti-carcinogenic compounds. One of the driving forces of colorectal carcinogenesis, in both sporadic and hereditary CRC, is the aberrant activation/regulation of the Wnt/β-catenin pathway. This review discusses reports of modulation of the Wnt/β-Catenin signaling pathway by dietary polyphenols (resveratrol, avenanthramides, epigallocatechinin, curcumin, quercetin, silibinin, genistein and mangiferin) specifically focusing on CRC, and proposes a model as to how this modulation occurs. There is potential for implementing these dietary polyphenols into preventative and therapeutic therapies for CRC as evidenced by some clinical trials that have been carried out with promising results.

Food-derived natural compounds in the management of chronic diseases via Wnt signaling pathway

Wnt signaling pathway is an evolutionarily conserved pathway that control embryonic development, adult tissue homeostasis, and pathological processes of organisms throughout life. However, dysregulation of the Wnt signaling is associated with the occurrence of chronic diseases. In comparison with the application of chemical drugs as traditional treatment for chronic diseases, dietary agents have unique advantages, such as less side effects, multiple targets, convenience in accessibility and higher acceptability in long-term intervention. In this review, we summarized current progress in manipulating the Wnt signaling using food components and its benefits in managing chronic diseases. The underlying mechanisms of bioactive food components in the management of the disease progression via the Wnt signaling was illustrated. Then, the review focused on the function of dietary pattern (which might act via combination of foods with multiple nutrients or food ingredients) on targeting Wnt signaling at multiple level. The potential caveats and challenges in developing new strategy via modulating Wnt-associated diseases with food-based agents and appropriate dietary pattern are also discussed in detail. This review shed light on the understanding of the regulatory effect of food bioactive components on chronic diseases management through the Wnt signaling, which can be expanded to other specific signaling pathway associated with disease.

A perspective on medicinal chemistry approaches towards adenomatous polyposis coli and Wnt signal based colorectal cancer inhibitors

Colorectal cancer (CRC) is one of the major causes of carcinogenic mortality in numbers only after lung and breast cancers. The mutations in adenomatous polyposis coli (APC) gene leads to formation of colorectal polyps in the colonic region and which develop as a malignant tumour upon coalition with patient related risk factors. The protein-protein interaction (PPI) of APC with Asef (A Rac specific guanine nucleotide exchange factor) overwhelms the patient's conditions by rapidly spreading in the entire colorectal region. Most mutations in APC gene occur in mutated cluster region (MCR), where it specifically binds with the cytosolic β-catenin to regulate the Wnt signalling pathway required for CRC cell adhesion, invasion, progression, differentiation and stemness in initial cell cycle phages. The current broad spectrum perspective is attempted to elaborate the sources of identification, development of selective APC inhibitors by targeting emopamil-binding protein (EBP) & dehydrocholesterol reductase-7 & 24 (DHCR-7 & 24); APC-Asef, β-catenin/APC, Wnt/β-catenin, β-catenin/TCF4 PPI inhibitors with other vital Wnt signal cellular proteins and APC/Pol-β interface of colorectal cancer. In this context, this perspective would serve as a platform for design of new medicinal agents by targeting cellular essential components which could accelerate anti-colorectal potential candidates.

Updated Review on the Role of Curcumin in Gastrointestinal Cancers

Malignant conditions of the gastrointestinal tract and accessory organs of digestion, including the oral cavity, esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus, are referred to as gastrointestinal cancers. Curcumin is a natural compound derived from turmeric with a wide range of biological activities. Several in vitro and in vivo studies have investigated the effects of curcumin on gastrointestinal cancers. In the current review, we aimed to provide an updated summary on the recent findings regarding the beneficial effects of curcumin on different gastrointestinal cancers in the recent decade. For this purpose, ScienceDirect," "Google Scholar," "PubMed," "ISI Web of Knowledge," and "Wiley Online Library" databases were searched using "curcumin", "cancer", and "gastrointestinal organs" as keywords. In vitro studies performed on different gastrointestinal cancerous cell lines have shown that curcumin can inhibit cell growth through cycle arrest at the G2/M and G1 phases, as well as stimulated apoptosis and autophagy by interacting with multiple molecular targets. In vivo studies performed in various animal models have confirmed mainly the chemopreventive effects of curcumin. Several nano-formulations have been proposed to improve the bioavailability of curcumin and increase its absorption. Moreover, curcumin has been used in combinations with many anti-tumor drugs to increase their anticarcinogenic properties. Taken together, curcumin falls within the category of plant-derived substances capable of preventing or treating gastrointestinal cancers. Further studies, particularly clinical trials, on the efficacy and safety of curcumin are suggested in this regard.

Implementing Curcumin in Translational Oncology Research

Most data published on curcumin and curcumin-based formulations are very promising. In cancer research, the majority of data has been obtained in vitro. Less frequently, researchers used experimental animals. The results of several clinical studies are conclusive, and these studies have established a good foundation for further research focusing on implementing curcumin in clinical oncology. However, the issues regarding timely data reporting and lack of disclosure of the exact curcumin formulations used in these studies should not be neglected. This article is a snapshot of the current status of publicly available data on curcumin clinical trials and a detailed presentation of results obtained so far with some curcumin formulations. Phenomena related to the observed effects of curcumin shown in clinical trials are presented, and its modifying effect on gut microbiota and metabolic reprogramming is discussed. Based on available data, there is a strong indication that curcumin and its metabolites present molecules that do not necessarily need to be abundant in order to act locally and benefit systemically. Future clinical studies should be designed in a way that will take that fact into consideration.

Curcumin Therapeutic Modulation of the Wnt Signaling Pathway

Curcumin, isolated from the rhizome of Curcuma longa, is one of the most extensively studied phytochemicals. This natural compound has a variety of pharmacological effects including antioxidant, anti-inflammatory, anti-tumor, cardio-protective, hepato-protective and anti-diabetic. Wnt signaling pathway, one of the potential targets of curcumin through upregulation and/or downregulation, plays a significant role in many diseases, even in embryogenesis and development of various organs and systems. In order to exert an anti-tumor activity in the organism, curcumin seems to inhibit the Wnt pathway. The downstream mediators of Wnt signaling pathway such as c-Myc and cyclin D1 are also modified by curcumin. This review demonstrates how curcumin influences the Wnt signaling pathway and is beneficial for the treatment of neurological disorders (Alzheimer's and Parkinson's diseases), cancers (melanoma, lung cancer, breast cancer, colon cancer, endothelial carcinoma, gastric carcinoma and hepatocellular carcinoma) and other diseases, such as diabetes mellitus or bone disorders.

Nature-derived compounds modulating Wnt/ -catenin pathway: a preventive and therapeutic opportunity in neoplastic diseases

The Wnt/β-catenin signaling is a conserved pathway that has a crucial role in embryonic and adult life. Dysregulation of the Wnt/β-catenin pathway has been associated with diseases including cancer, and components of the signaling have been proposed as innovative therapeutic targets, mainly for cancer therapy. The attention of the worldwide researchers paid to this issue is increasing, also in view of the therapeutic potential of these agents in diseases, such as Parkinson's disease (PD), for which no cure is existing today. Much evidence indicates that abnormal Wnt/β-catenin signaling is involved in tumor immunology and the targeting of Wnt/β-catenin pathway has been also proposed as an attractive strategy to potentiate cancer immunotherapy. During the last decade, several products, including naturally occurring dietary agents as well as a wide variety of products from plant sources, including curcumin, quercetin, berberin, and ginsenosides, have been identified as potent modulators of the Wnt/β-catenin signaling and have gained interest as promising candidates for the development of chemopreventive or therapeutic drugs for cancer. In this review we make an overview of the nature-derived compounds reported to have antitumor activity by modulating the Wnt/β-catenin signaling, also focusing on extraction methods, chemical features, and bio-activity assays used for the screening of these compounds.

Curcumin may reverse 5-fluorouracil resistance on colonic cancer cells by regulating TET1-NKD-Wnt signal pathway to inhibit the EMT progress

BACKGROUND AND PURPOSE

Colorectal cancer is a kind of gastrointestinal tumor with rising morbidity and mortality. 5-fluorouracil is one of the most effective chemotherapy drugs for the treatment of CRC. However, clinical data reported dramatic resistance on the treatment for CRC with 5-fluorouracil. Present study aims to explore the anti-resistant effect of curcumin and its mechanism.

METHODS

MTT assay was used to evaluate the proliferation of rHCT-116 cells. Flow cytometry was used to determine the apoptosis and cell cycle of rHCT-116 cells. Western Blot was performed to detect the expression level of TET1, NKD2, E-cadherin, Vimentin, β-catenin, TCF4 and Axin in transfected rHCT-116 cells.

RESULTS

5-fluorouracil resistant HCT-116 cells were successfully established. Curcumin was found to be effective in the inhibition of proliferation, inducement of apoptosis and block of G0/G1 phase on 5-fluorouracil treated HCT-116 cells. The expression of TET1 and NKD2 was greatly inhibited by high dosage of curcumin. The WNT signal pathway and EMT progress were suppressed in rHCT-116 cells by high dosage of curcumin. The inhibitory effects of curcumin on WNT signal pathway and EMT progress were verified to be consistent with Pax-6, TET1 and NKD2.

CONCLUSION

Curcumin might exert anti-resistant effect of 5-FU on HCT-116 cells by regulating the TET1-NKD2-WNT signal pathway to inhibit the EMT progress.

Curcumin Affects Gastric Cancer Cell Migration, Invasion and Cytoskeletal Remodeling Through Gli1-β-Catenin

Purpose

The function of curcumin on the gastric cancer cell line, SGC-7901 is unknown. The present study aimed to observe the effects of curcumin on gastric cancer cells through the Shh and Wnt signaling pathways.

Methods

SGC-7901 cells were transfected with si-Gli1 and si-β-catenin siRNA, then cells were stimulated with curcumin and its effects on cell migration, invasion, cytoskeleton remodeling, EMT, apoptosis and cell cycle were investigated by transwell assays, immunofluorescence and flow cytometry assays. The interaction between Gli1 and β-catenin was observed by co-immunoprecipitation.

Results

We show that curcumin suppressed the expression of Shh, Gli1 and Foxm1 in the Shh signaling pathway, and the expression of β-catenin in the Wnt signaling pathway in SGC-7901 cells, both in mRNA and protein. As a result, cellular migration, invasion and cytoskeletal remodeling ability decreased. Our results revealed that when stimulated with curcumin, cells showed decreased cellular migration and invasion, while enhanced apoptosis. In addition, curcumin induced cytoskeletal remodeling and S phase cell cycle arrest. The inhibition of Shh and Wnt signaling pathway and the addition of curcumin also inhibited the epithelial–mesenchymal transition process. Furthermore, a physical interaction was observed between Gli1 of the Shh signaling and β-catenin of the Wnt signaling in these cells, but curcumin inhibited the interaction of these two proteins.

Conclusion

The present study indicated that curcumin plays an anti-tumor role through Gli1-β-catenin pathway in gastric cancer SGC-7901 cells.

Small Molecule Wnt Pathway Modulators from Natural Sources: History, State of the Art and Perspectives

The Wnt signaling is one of the major pathways known to regulate embryonic development, tissue renewal and regeneration in multicellular organisms. Dysregulations of the pathway are a common cause of several types of cancer and other diseases, such as osteoporosis and rheumatoid arthritis. This makes Wnt signaling an important therapeutic target. Small molecule activators and inhibitors of signaling pathways are important biomedical tools which allow one to harness signaling processes in the organism for therapeutic purposes in affordable and specific ways. Natural products are a well known source of biologically active small molecules with therapeutic potential. In this article, we provide an up-to-date overview of existing small molecule modulators of the Wnt pathway derived from natural products. In the first part of the review, we focus on Wnt pathway activators, which can be used for regenerative therapy in various tissues such as skin, bone, cartilage and the nervous system. The second part describes inhibitors of the pathway, which are desired agents for targeted therapies against different cancers. In each part, we pay specific attention to the mechanisms of action of the natural products, to the models on which they were investigated, and to the potential of different taxa to yield bioactive molecules capable of regulating the Wnt signaling.

Curcumin and colorectal cancer: An update and current perspective on this natural medicine

Colorectal cancer (CRC) is one of most common malignancies worldwide and its incidence is still growing. In spite of recent advances in targeted therapies, their clinical efficacy has been limited, non-curative and unaffordable. A growing body of literature indicates that CRC is a multi-modal disease, where a variety of factors within the tumor microenvironment play a significant role in its pathogenesis. For instance, imbalance in gut microbial profiles and impaired intestinal barrier function contribute to the overall intestinal inflammation and initiation of CRC. Moreover, persistent chronic inflammation favors a tumor microenvironment for the growth of cancer. In addition, autophagy or 'self-eating' is a surveillance mechanism involved in the degradation of cellular constituents that are generated under stressful conditions. Cancer stem cells (CSCs), on the other hand, engage in the onset of CRC and are able to endow cancer cells with chemo-resistance. Furthermore, the aberrant epigenetic alterations promote CRC. These evidences highlight the need for multi-targeted approaches that are not only safe and inexpensive but offer a more effective alternative to current generation of targeted drugs. Curcumin, derived from the plant Curcuma longa, represents one such option that has a long history of its use for a variety of chronic disease including cancer, in Indian ayurvedic and traditional Chinese medicine. Scientific evidence over the past few decades have overwhelmingly shown that curcumin exhibits a multitude of anti-cancer activities orchestrated through key signaling pathways associated with cancer. In this article, we will present a current update and perspective on this natural medicine - incorporating the basic cellular mechanisms it effects and the current state of clinical evidence, challenges and promise for its use as a cancer preventative and potential adjunct together with modern therapies for CRC patients.

Molecular mechanisms of curcumin and its analogs in colon cancer prevention and treatment

Colorectal cancer remains to be the most prevalent malignancy in humans and 1.5 million men and women living in the United States are diagnosed with colorectal cancer, with a predicted 145,600 new cases to be diagnosed in 2019. Curcuminoids and its synthetic analogs are now of interest due to their bioactive attributes, especially their action as anticancer activity in various cancer cell line models. Several in vivo and in vitro studies have substantially proved their anticancer activities against colon cancer cell lines. Curcumin analogues like IND-4, FLLL, GO-Y030 and C086 have demonstrated to produce greater cytotoxicity when experimentally studied and study results from many have been suggested to be the same. Combination of curcumin with therapeutic cancer agents like tolfenamic acid, 5-fluorouracil, resveratrol and dasatinib showed improved cytotoxicity and chemotherapeutic effect. The results propose that employment of curcumin with novel drug delivery systems like liposome, micelles and nanoparticle have been performed which could improve the therapeutic efficacy against colon cancer. The present review highlights the mechanism of action, synergistic effect and novel delivery methods to improve the therapeutic potential of curcumin.

Radiosensitizing effect of curcumin-loaded lipid nanoparticles in breast cancer cells

In breast cancer (BC) care, radiotherapy is considered an efficient treatment, prescribed both for controlling localized tumors or as a therapeutic option in case of inoperable, incompletely resected or recurrent tumors. However, approximately 90% of BC-related deaths are due to the metastatic tumor progression. Then, it is strongly desirable to improve tumor radiosensitivity using molecules with synergistic action. The main aim of this study is to develop curcumin-loaded solid nanoparticles (Cur-SLN) in order to increase curcumin bioavailability and to evaluate their radiosensitizing ability in comparison to free curcumin (free-Cur), by using an in vitro approach on BC cell lines. In addition, transcriptomic and metabolomic profiles, induced by Cur-SLN treatments, highlighted networks involved in this radiosensitization ability. The non tumorigenic MCF10A and the tumorigenic MCF7 and MDA-MB-231 BC cell lines were used. Curcumin-loaded solid nanoparticles were prepared using ethanolic precipitation and the loading capacity was evaluated by UV spectrophotometer analysis. Cell survival after treatments was evaluated by clonogenic assay. Dose–response curves were generated testing three concentrations of free-Cur and Cur-SLN in combination with increasing doses of IR (2–9 Gy). IC₅₀ value and Dose Modifying Factor (DMF) was measured to quantify the sensitivity to curcumin and to combined treatments. A multi-“omic” approach was used to explain the Cur-SLN radiosensitizer effect by microarray and metobolomic analysis. We have shown the efficacy of the Cur-SLN formulation as radiosensitizer on three BC cell lines. The DMFs values, calculated at the isoeffect of SF = 50%, showed that the Luminal A MCF7 resulted sensitive to the combined treatments using increasing concentration of vehicled curcumin Cur-SLN (DMF: 1,78 with 10 µM Cur-SLN.) Instead, triple negative MDA-MB-231 cells were more sensitive to free-Cur, although these cells also receive a radiosensitization effect by combination with Cur-SLN (DMF: 1.38 with 10 µM Cur-SLN). The Cur-SLN radiosensitizing function, evaluated by transcriptomic and metabolomic approach, revealed anti-oxidant and anti-tumor effects. Curcumin loaded- SLN can be suggested in future preclinical and clinical studies to test its concomitant use during radiotherapy treatments with the double implications of being a radiosensitizing molecule against cancer cells, with a protective role against IR side effects.

Resveratrol inhibits the invasion and metastasis of colon cancer through reversal of epithelial‑ mesenchymal transition via the AKT/GSK‑3β/Snail signaling pathway

The identification of safe and effective drugs that inhibit tumor invasion and metastasis is required to improve the clinical outcome of patients with colon cancer. The present study aimed to investigate the inhibitory effects and possible mechanisms of action of resveratrol against the invasion and metastasis of colon cancer. AKT1-knockdown SW480 and SW620 colon cancer cells were used to detect the effects of resveratrol on cell invasion and metastasis, as well as changes in the expression of epithelial-mesenchymal transition (EMT) markers and serine/threonine kinase (AKT)/glycogen synthase kinase (GSK)-3β/Snail signaling pathway-related molecules in vitro. Furthermore, nude mice were inoculated with SW480 cells in the tail vein to establish an in vivo lung metastasis model of colon cancer, to investigate the effects of resveratrol on lung metastasis in colon cancer. The results revealed that resveratrol treatment and AKT1 knockdown significantly inhibited cell migration and invasion in colon cancer, and markedly increased E-cadherin expression and decreased that of N-cadherin, phospho (p)-AKT1, p-GSK-3β, and Snail in colon cancer both in vitro and in vivo. Furthermore, the effects of resveratrol were significantly weaker in the AKT1-knockdown cells. In conclusion, resveratrol may suppress the invasion and metastasis of colon cancer through reversal of EMT via the AKT/GSK-3β/Snail signaling pathway. AKT1 may therefore be a key regulator of EMT in colon cancer cells and a potential therapeutic target for this disease.

Tanshinone prevents alveolar bone loss in ovariectomized osteoporosis rats by up-regulating phosphoglycerate dehydrogenase

Osteoporosis is manifested by reduced bone mass. Tanshinone has been shown to affect osteoclast differentiation, but its role in osteoporosis remains less clear. This study aimed to investigate the effects and molecular mechanisms of tanshinone on osteoporosis. Osteoporosis was induced by bilateral ovariectomy (OVX) in adult female rats treated with or without tanshinone. Trabecular bone structure was assessed by micro-computed tomography (micro-CT). Bone marrow stromal cells (BMSCs) were isolated for analysis of stemness and senescence. mRNA levels of age related genes were examined and the role of the gene that was upregulated by tanshinone treatment was suppressed to determine its involvement in tanshinone mediated effects. Finally, the mechanism underlying tanshinone induced gene upregulation was explored. We found that tanshinone treatment restored alveolar bone structure in OVX rats as well as the stemness and senescence status of BMSCs isolated from OVX rats. Tanshinone upregulated Phgdh mRNA levels and inhibition of phosphoglycerate dehydrogenase Phgdh, the protein encoded by the Phgdh gene, abolished the effects of tanshinone on BMSC stemness and senescence. Finally, we found that OVX lead to hypermethylation of the promoter region of Phgdh which was suppressed by tanshinone treatment. Our study shows that tanshinone potently suppress OVX induced osteoporosis and BMSC senescence through upregulation of PHGDH.

Potential Mechanisms of Action of Curcumin for Cancer Prevention: Focus on Cellular Signaling Pathways and miRNAs

Despite significant progressions in treatment modalities over the last decade, either cancer incidence or mortality is continuously on the rise throughout the world. Current anticancer agents display limited efficacy, accompanied by severe side effects. In order to improve therapeutic outcomes in patients with cancer, it is crucial to identify novel, highly efficacious pharmacological agents. Curcumin, a hydrophobic polyphenol extracted from turmeric, has gained increasing attention due to its powerful anticancer properties. Curcumin can inhibit the growth, invasion and metastasis of various cancers. The anticancer mechanisms of curcumin have been extensively studied. The anticancer effects of curcumin are mainly mediated through its regulation of multiple cellular signaling pathways, including Wnt/β-catenin, PI3K/Akt, JAK/STAT, MAPK, p53 and NF-ĸB signaling pathways. Moreover, curcumin also orchestrates the expression and activity of oncogenic and tumor-suppressive miRNAs. In this review, we summarized the regulation of these signaling pathways by curcumin in different cancers. We also discussed the modulatory function of curcumin in the downregulation of oncogenic miRNAs and the upregulation of tumor-suppressive miRNAs. An in-depth understanding of the anticancer mechanisms of curcumin will be helpful for developing this promising compound as a therapeutic agent in clinical management of cancer.

Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in tumor progression, invasion, migration and metastasis. EMT is a process by which polarized epithelial cells acquire motile mesothelial phenotypic features. This process is initiated by disassembly of cell-cell contacts through the loss of epithelial markers and replacement of these markers by mesenchymal markers. Reconstruction of the cytoskeleton and degradation of the tumor basement membrane ensures the spread of invasive malignant tumor cells to distant locations. Accumulating evidence indicates that curcumin, as a well-known phytochemical, can inhibit EMT/metastasis through various mechanisms and pathways in human tumors.

CONCLUSIONS

In this review, we summarize the mechanisms by which curcumin may affect EMT in cells under pathological conditions to understand its potential as a novel anti-tumor agent. Curcumin can exert chemo-preventive effects by inhibition and reversal of the EMT process through both TGF-β-dependent (e.g. in hepatoma and retinal pigment epithelial cancer) and -independent (e.g. in oral cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, breast cancer, melanoma, prostate cancer, bladder cancer, thyroid cancer and lung cancer) pathways. Curcumin can also mitigate chemoresistance through EMT suppression and promotion of the antiproliferative effects of conventional chemotherapeutics. Therefore, curcumin has the potential to be used as a novel adjunctive agent to prevent tumor metastasis, which may at least partly be attributed to its hampering of the EMT process.

Traditional Chinese medicine as a cancer treatment: Modern perspectives of ancient but advanced science

Traditional Chinese medicine (TCM) has been practiced for thousands of years and at the present time is widely accepted as an alternative treatment for cancer. In this review, we sought to summarize the molecular and cellular mechanisms underlying the chemopreventive and therapeutic activity of TCM, especially that of the Chinese herbal medicine-derived phytochemicals curcumin, resveratrol, and berberine. Numerous genes have been reported to be involved when using TCM treatments and so we have selectively highlighted the role of a number of oncogene and tumor suppressor genes in TCM therapy. In addition, the impact of TCM treatment on DNA methylation, histone modification, and the regulation of noncoding RNAs is discussed. Furthermore, we have highlighted studies of TCM therapy that modulate the tumor microenvironment and eliminate cancer stem cells. The information compiled in this review will serve as a solid foundation to formulate hypotheses for future studies on TCM-based cancer therapy.

The molecular mechanisms of curcumin’s inhibitory effects on cancer stem cells

Curcumin is a dietary polyphenol and a bioactive phytochemical that possesses anti‐inflammatory, antioxidant, anticancer, and chemopreventive properties, which make it capable of affecting multiple sites along the stem cell pathways to induce apoptosis in these cells. Curcumin’s function is through suppression of cytokine release, especially the secretion of interleukins. Some of the predominant activities of stem cells include regeneration of identical cells and the ability to maintain the proliferation and multipotentiality. However, these cells could be stimulated to differentiate into specific cell types, leading to the development of tumors. Cancer stem cells (CSC) are capable of sustaining tumor formation and differentiation, and are normally characterized by self‐renewal mechanisms. Furthermore, these cells might be responsible for tumor relapse and resistance to therapy. Several studies have focused on the mechanisms of curcumin action in manipulating transcription factors, signaling pathways, CSC markers, microRNAs related to CSCs functions and apoptosis induction in various human cancer cells. In the present review, we aimed to summarize the reported molecular mechanisms of curcumin’s effects on CSCs.

Cellular and molecular mechanisms of curcumin in prevention and treatment of disease

Curcumin is a naturally occurring polyphenolic compound present in rhizome of Curcuma longa belonging to the family zingiberaceae. Growing experimental evidence revealed that curcumin exhibit multitarget biological implications signifying its crucial role in health and disease. The current review highlights the recent progress and mechanisms underlying the wide range of pharmacological effects of curcumin against numerous diseases like neuronal, cardiovascular, metabolic, kidney, endocrine, skin, respiratory, infectious, gastrointestinal diseases and cancer. The ability of curcumin to modulate the functions of multiple signal transductions are linked with attenuation of acute and chronic diseases. Numerous preclinical and clinical studies have revealed that curcumin modulates several molecules in cell signal transduction pathway including PI3K, Akt, mTOR, ERK5, AP-1, TGF-β, Wnt, β-catenin, Shh, PAK1, Rac1, STAT3, PPARγ, EBPα, NLRP3 inflammasome, p38MAPK, Nrf2, Notch-1, AMPK, TLR-4 and MyD-88. Curcumin has a potential to prevent and/or manage various diseases due to its anti-inflammatory, anti-oxidant and anti-apoptotic properties with an excellent safety profile. In contrast, the anti-cancer effects of curcumin are reflected due to induction of growth arrest and apoptosis in various premalignant and malignant cells. This review also carefully emphasized the pharmacokinetics of curcumin and its interaction with other drugs. Clinical studies have shown that curcumin is safe at the doses of 12 g/day but exhibits poor systemic bioavailability. The use of adjuvant like piperine, liposomal curcumin, curcumin nanoparticles and curcumin phospholipid complex has shown enhanced bioavailability and therapeutic potential. Further studies are warranted to prove the potential of curcumin against various ailments.

Curcumin-Mediated Induction of Apoptosis in Human Glioma CHME Cells

Background

Curcumin has clear anti-tumor activity in various carcinomas. It regulates various signaling pathways like Wnt/β-catenin and JAK2/STAT3, which play vital roles in cell proliferation of several carcinomas, but to the best of our knowledge, there are currently no published reports on human glioma CHME cells. Therefore, the aim of this study was to explore the effect of curcumin on human glioma CHME cells.

Material/Methods

The CHME cell line was purchased from American Type Culture Collection (ATCC). The expressions of caspases 3, caspases 9, PARP, BAX, and BCL2 were detected by Western blot. Annexin V FITC, mitochondrial membrane potential, and reactive oxygen species were detected by flow cytometry. DAPI staining was detected by fluorescence microscopy. Cell viability was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay.

Results

We found that curcumin has cytotoxic activity in human glioma CHME cells, as shown by DAPI staining, annexin V/PI, and nuclear morphology. We found that cell growth decreased with increased concentration of curcumin, as well as sowing effects on expression of caspase-3, caspase-9, and cleavage of PARP, which suggests apoptotic cascade activity. The increase in reactive oxygen species and loss of mitochondrial membrane potential (Δψmt) in concentration-dependent manners suggests biochemical induction of apoptosis in CHME cells.

Conclusions

Curcumin has effective anticancer activity in human glioma CHME cells by inducing the apoptotic pathway.

Dietary phytochemicals in colorectal cancer prevention and treatment: A focus on the molecular mechanisms involved

Worldwide, colorectal cancer (CRC) remains a major cancer type and leading cause of death. Unfortunately, current medical treatments are not sufficient due to lack of effective therapy, adverse side effects, chemoresistance and disease recurrence. In recent decades, epidemiologic observations have highlighted the association between the ingestion of several phytochemical-enriched foods and nutrients and the lower risk of CRC. According to preclinical studies, dietary phytochemicals exert chemopreventive effects on CRC by regulating different markers and signaling pathways; additionally, the gut microbiota plays a role as vital effector in CRC onset and progression, therefore, any dietary alterations in it may affect CRC occurrence. A high number of studies have displayed a key role of growth factors and their signaling pathways in the pathogenesis of CRC. Indeed, the efficiency of dietary phytochemicals to modulate carcinogenic processes through the alteration of different molecular targets, such as Wnt/β-catenin, PI3K/Akt/mTOR, MAPK (p38, JNK and Erk1/2), EGFR/Kras/Braf, TGF-β/Smad2/3, STAT1-STAT3, NF-кB, Nrf2 and cyclin-CDK complexes, has been proven, whereby many of these targets also represent the backbone of modern drug discovery programs. Furthermore, epigenetic analysis showed modified or reversed aberrant epigenetic changes exerted by dietary phytochemicals that led to possible CRC prevention or treatment. Therefore, our aim is to discuss the effects of some common dietary phytochemicals that might be useful in CRC as preventive or therapeutic agents. This review will provide new guidance for research, in order to identify the most studied phytochemicals, their occurrence in foods and to evaluate the therapeutic potential of dietary phytochemicals for the prevention or treatment of CRC by targeting several genes and signaling pathways, as well as epigenetic modifications. In addition, the results obtained by recent investigations aimed at improving the production of these phytochemicals in genetically modified plants have been reported. Overall, clinical data on phytochemicals against CRC are still not sufficient and therefore the preventive impacts of dietary phytochemicals on CRC development deserve further research so as to provide additional insights for human prospective studies.

Oral administration of curcumin attenuates visceral hyperalgesia through inhibiting phosphorylation of TRPV1 in rat model of ulcerative colitis

Background Curcumin has been reported to have anti-inflammatory and anti-nociceptive effects. The present study was designed to explore the potential therapeutic effects of curcumin on visceral hyperalgesia and inflammation in a rat model of ulcerative colitis. We observed the effects of orally administered curcumin on the disease activity index, histological change in colon, colorectal distension-induced abdominal withdrawal reflex, the expression of transient receptor potential vanilloid 1 (TRPV1) and phosphorylated TRPV1 in dextran sulfate sodium-induced colitis rats. In addition, a HEK293 cell line stably expressing human TRPV1 (hTRPV1) was used to examine the effects of curcumin on the change in membrane expression of TRPV1 induced by phorbol myristate acetate (a protein kinase C activator). Results Repeated oral administration of curcumin inhibited the increase in abdominal withdrawal reflex score induced by dextran sulfate sodium without affecting dextran sulfate sodium-induced histological change of colon and the disease activity index. A significant increase in colonic expression of TRPV1 and pTRPV1 was observed in dextran sulfate sodium-treated rats and this was reversed by oral administration of curcumin. TRPV1 expression in L6-S1 dorsal root ganglion was increased in the small- to medium-sized isolectin B4-positive non-peptidergic and calcitonin gene-related peptide-positive peptidergic neurons in dextran sulfate sodium-treated rats and oral administration of curcumin mitigated such changes. In the HEK293 cell line stably expressing hTRPV1, curcumin (1, 3 µm) inhibited phorbol myristate acetate-induced upregulation of membrane TRPV1. Conclusion Oral administration of curcumin alleviates visceral hyperalgesia in dextran sulfate sodium-induced colitis rats. The anti-hyperalgesic effect is partially through downregulating the colonic expression and phosphorylation of TRPV1 on the afferent fibers projected from peptidergic and non-peptidergic nociceptive neurons of dorsal root ganglion.

CXCR4 overexpression is correlated with poor prognosis in colorectal cancer

AIMS

Colorectal cancer threatens human health due to its high mortality resulting from metastatic progression. The expression of C-X-C chemokine receptor type 4 (CXCR4) is absent or low in most healthy tissues but high in various types of tumours. In this study, we aim to determine the prognostic significance of CXCR4 in colorectal cancer.

MAIN METHODS

We retrospectively examined a total of 72 tissue samples, that qRT-PCR and immunohistochemistry were performed to detect the expression of CXCR4 as well as univariate and multivariate analyses were performed to explore the overall survival.

KEY FINDINGS

Our data demonstrated that CXCR4 expression was associated with lymph node metastasis (P = 0.049), histological differentiation (P = 0.01), distant metastasis (P = 0.02) and DNA mismatch repair (MMR) index (P = 0.0002). However, CXCR4 expression was not associated with age, sex, tumour diameter or depth of invasion. Furthermore, both univariate and multivariate analyses confirmed that CXCR4 was an independent factor in predicting unfavourable overall survival (hazard ratio, 0.188; 95% confidence interval, 0.038-0.757).

SIGNIFICANCE

In conclusion, our findings suggest that CXCR4 might contribute to clinical tumour progression and may be a valuable prognostic biomarker in colorectal cancer treatment.

Curcumin on the "flying carpets" to modulate different signal transduction cascades in cancers: Next-generation approach to bridge translational gaps

Curcumin, a bioactive and pharmacologically efficient component isolated from Curcuma longa has attracted considerable attention because of its ability to modulate diverse cellular and physiological pathways. WNT, TGF/SMAD, NOTCH, and SHH are fundamentally different signaling cascades, but their choreographed activation is strongly associated with cancer development and progression. In this review we have attempted to set spotlight on regulation of different cell signaling pathways by curcumin in different cancers. We partition this multi-component review into in-depth biological understanding of various signal transduction cascades and how curcumin targets intracellular signal transducers of deregulated pathways to inhibit cancer development and progression. Rapidly broadening landscape of both established and candidate oncogenic driver mutations identified in different cancers is a major stumbling block in the standardization of drugs having significant clinical outcome. Intra and inter-tumor heterogeneity had leveraged the complexity of therapeutic challenges to another level. Multi-pronged approach and molecularly guided treatments will be helpful in improving the clinical outcome.