Inhibition of autophagy attenuated curcumol-induced apoptosis in MG-63 human osteosarcoma cells via Janus kinase signaling pathway

Curcumol: a review of its pharmacology, pharmacokinetics, drug delivery systems, structure-activity relationships, and potential applications

Curcumol (Cur), a guaiane-type sesquiterpenoid hemiketal, is an important and representative bioactive component extracted from the essential oil of the rhizomes of Curcumae rhizoma which is also known as "Ezhu" in traditional Chinese medicine. Recently, Cur has received considerable attention from the research community due to its favorable pharmacological activities, including anti-cancer, hepatoprotective, anti-inflammatory, anti-viral, anti-convulsant, and other activities, and has also exerted therapeutic effect on various cancers, liver diseases, inflammatory diseases, and infectious diseases. Pharmacokinetic studies have shown that Cur is rapidly distributed in almost all organs of rats after intragastric administration with high concentrations in the small intestine and colon. Several studies focusing on structure-activity relationship (SAR) of Cur have shown that some Cur derivatives, chemically modified at C-8 or C-14, exhibited more potent anti-cancer activity and lower toxicity than Cur itself. This review aims to comprehensively summarize the latest advances in the pharmacological and pharmacokinetic properties of Cur in the last decade with a focus on its anti-cancer and hepatoprotective potentials, as well as the research progress in drug delivery system and potential applications of Cur to date, to provide researchers with the latest information, to highlighted the limitations of relevant research at the current stage and the aspects that should be addressed in future research. Our results indicate that Cur and its derivatives could serve as potential novel agents for the treatment of a variety of diseases, particularly cancer and liver diseases.

Curcumol increases the sensitivity of colon cancer to 5-FU by regulating Wnt/β-catenin signaling

Background

5-fluorouracil (5-FU) resistance is the leading cause of treatment failure in colon cancer. Combination therapy is an effective strategy to inhibit cancer cells and prevent drug resistance. Therefore, we studied the antitumor effect of curcumol alone or combined with 5-FU on human colon cancer drug-resistant cells.

Methods

The 5-FU resistant HCT116 cell line (HCT116/5-FU) was established by repeated exposure to gradually increasing concentrations of 5-FU; Cell viability was measured by cell counting kit-8 (CCK-8); apoptosis rate of HCT116 cells was detected using Annexin V-fluorescein isothiocyanate (FITC) assay kit; cell proliferation and invasion were detected using colony formation assays, wound healing assay and transwell invasion assays; activity of transplanted tumor in vivo in specific pathogen free (SPF) BALB/c nude mice (6 weeks old, male) was monitored by bioluminescence imaging, immunohistochemistry and western blot analysis.

Results

Our study showed the potent antitumor effect of curcumol by induction of apoptosis, inhibition of proliferation, invasion, migration, and improvement of the therapeutic efficacy of 5-FU toward human colon cancer HCT116 cells. From our results, curcumol could chemosensitize 5-FU-resistant HCT116 cells. The combination of curcumol and 5-FU exerted a synergistic inhibitory effect on the induction of apoptosis. Also, this combination inhibited the proliferation, invasion, and migration of both chemo-resistant and sensitive cells. Curcumol treatment decreased multidrug resistance-associated protein 2 (MRP-2), P-glycoprotein (P-gp), survivin, and β-catenin expression, which correlated with multidrug resistance (MDR) and the target genes of Wnt/β-catenin. It significantly increased the p-β-catenin level and Bad/Bcl-2 ratio in HCT116/5-FU cells compared with 5-FU treatment. In vivo, curcumol significantly inhibited the growth of transplanted tumors and the expression of Ki-67, proliferating cell nuclear antigen (PCNA), and vascular endothelial growth factor (VEGF) in colon cancer cells.

Conclusions

Curcumol as a potential chemotherapeutic agent combined with 5-FU can overcome colon cancer resistance.

Diosgenin inhibits Wnt/β-catenin pathway to regulate the proliferation and differentiation of MG-63 cells

Dioscorea opposita Thunb has the effect of anti-osteoporosis, but whether its active ingredient diosgenin (DIO) has an anti-osteoporosis effect is unknown. The purpose of this study is to investigate the effect of DIO on the proliferation and differentiation of MG-63 cells. MG-63 cells were treated with different concentrations of DIO (0.001, 0.01, 0.1 and 1 μM) or 20 mM Wnt/β-catenin signaling agonist-LiCl, and then their cell cycle and viability were analyzed by flow cytometry and 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), respectively. To investigate osteoblast differentiation, alizarin red staining and ultraviolet spectrophotometer were used to determine the number of calcified nodules and the activity of alkaline phosphatase (ALP), respectively. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting were used to detect the expressions of proliferation-related, osteogenic-related and Wnt/β-catenin signal pathway-related factors. After the cells were treated with low-concentration (0.001 or 0.01 μM) DIO, cell viability was significantly increased and the proportion of cells in S phase was increased. In addition, low-concentration DIO could significantly increase the expression of Ki67, proliferating cell nuclear antigen (PCNA), osteopontin (OPN), and osteocalcin (BGP), promote osteoblast differentiation, and suppress the expression of β-catenin, Runx2 and cyclinD1. However, high concentrations of DIO showed the opposite effect. Low-concentration DIO obviously reversed the effect of LiCl on decreasing the number of calcified nodules and inhibiting the expression of OPN and BGP in cells. Low-concentration DIO might promote the proliferation and differentiation of MG-63 cell by inhibiting the Wnt/β-catenin signal pathway.

Curcumol enhances the anti-tumor effects of metformin via suppressing epithelial-mesenchymal transition in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a severe disease with a high mortality rate. Metformin has been found to possess anti-tumor properties. Curcumol, an active ingredient extracted from curcuma, exerts the protective effect in TNBC cells through inducing apoptosis. However, the effects of curcumol combined with metformin on the treatment of TNBC have yet to be fully established.

Methods

TNBC cells MDA-MB-231 and MDA-MB-468 cells were used in the study. TNBC cells were treated with curcumol and metformin alone or treated with curcumol combined with metformin. Cell viability was determined using Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The levels of proteins were measured using Western blot. Wound healing assay and Transwell invasion assays were used to determine cell migration and invasion ability, respectively. A xenograft model was established to investigate the tumor growth ability. Immunohistochemistry was performed to determine the expression of Ki-67 and Vascular endothelial growth factor (VEGF).

Results

In the study, the administration of curcumol alone had no significant effects on the TNBC cells. However, the anti-proliferation, anti-metastasis, and anti-epithelial-mesenchymal transition (EMT) effects of metformin were enhanced by the addition of curcumol. Further, curcumol reversed TNBC cell proliferation, migration, invasion, and EMT induced by rucaparib, and enhanced the effect of metformin on rucaparib-induced TNBC cells. The combination of curcumol and metformin also suppressed tumor growth, EMT marker expression, and the activation of Wnt2/β-Catenin signaling during in vivo experiments.

Conclusions

The combination of curcumol and metformin enhances the anti-tumor effects of metformin on TNBC via inhibiting EMT. Curcumol combined with metformin may hold promise as a therapeutic strategy for TNBC.

Curcumol Inhibits Lung Adenocarcinoma Growth and Metastasis via Inactivation of PI3K/AKT and Wnt/-Catenin Pathway

Curcumol (Cur), isolated from the Traditional Chinese Medical plant Rhizoma Curcumae, is the bioactive component of sesquiterpene reported to possess antitumor activity. However, its bioactivity and mechanisms against lung adenocarcinoma are still unclear. We investigated its effect on lung adenocarcinoma and elucidated its underlying molecular mechanisms. In vitro, Cur effectively suppressed proliferation, migration, and invasion of lung adenocarcinoma cells A549 and H460, which were associated with the altered expressions of signaling molecules, including p-AKT, p-PI3K, p-LRP5/6, AXIN, APC, GSK3 and p--catenin, matrix metalloproteinase (MMP)-2, and MMP-9. Furthermore, Cur significantly induced cell apoptosis of A549 and H460 by promoting the expression of Bax, caspase 3, and caspase 9 and suppressing the expression of Bcl-2, and arrested the cell cycle at the G₀/G₁ phase by lowering the levels of cyclin D1, CDK1, and CDK4. In vivo experiment revealed that Cur could inhibit lung tumor growth and lung metastasis, which were consistent with these in vitro results. In xenograft model mice, Cur strongly decreased tumor weight and tumor volume, which may be related to the downregulation of p-AKT and p-PI3K by immunofluorescence analysis. In addition, a lung metastasis model experiment suggested that Cur dramatically decreased the ratio of lung/total weight, tumor metastatic nodules, and the expressions of MMP-2 and MMP-9 in lung tissues compared with the control. Overall, these data suggested that the inhibitory activity of Cur on lung adenocarcinoma via the inactivation of PI3K/Akt and Wnt/-catenin pathways, at least in part, indicates that curcumol may be a potential antitumor agent for lung adenocarcinoma therapy.

Anticancer activities of phytoconstituents and their liposomal targeting strategies against tumor cells and the microenvironment

Various bioactive ingredients have been extracted from Chinese herbal medicines (CHMs) that affect tumor progression and metastasis. To further understand the mechanisms of CHMs in cancer therapy, this article summarizes the effects of five categories of CHMs and their active ingredients on tumor cells and the tumor microenvironment. Despite their treatment potential, the undesirable physicochemical properties (poor permeability, instability, high hydrophilicity or hydrophobicity, toxicity) and unwanted pharmacokinetic profiles (short half-life in blood and low bioavailability) restrict clinical studies of CHMs. Therefore, development of liposomes through relevant surface modifying techniques to achieve targeted CHM delivery for cancer cells, i.e., extracellular and intracellular targets and targets in tumor microenvironment or vasculature, have been reviewed. Current challenges of liposomal targeting of these phytoconstituents and future perspective of CHM applications are discussed to provide an informative reference for interested readers.

Targeting autophagy is a promising therapeutic strategy to overcome chemoresistance and reduce metastasis in osteosarcoma

Osteosarcoma (OS) is the most common primary bone malignancy, mainly affecting children and adolescents. Currently, surgical resection combined with adjuvant chemotherapy has been standardized for OS treatment. Despite great advances in chemotherapy for OS, its clinical prognosis remains far from satisfactory; this is due to chemoresistance, which has become a major obstacle to improving OS treatment. Autophagy, a catabolic process through which cells eliminate and recycle their own damaged proteins and organelles to provide energy, can be activated by chemotherapeutic drugs. Accumulating evidence has indicated that autophagy plays the dual role in the regulation of OS chemoresistance by either promoting drug resistance or increasing drug sensitivity. The aim of the present review was to demonstrate thatautophagy has both a cytoprotective and an autophagic cell death function in OS chemoresistance. In addition, methods to detect autophagy, autophagy inducers and inhibitors, as well as autophagy‑mediated metastasis, immunotherapy and clinical prognosis are also discussed.

Curcumol: From Plant Roots to Cancer Roots

Natural products, an infinite treasure of bioactive scaffolds, have provided an excellent reservoir for the discovery of drugs since millennium. These naturally occurring, biologically active and therapeutically effective chemical entities have emerged as novel paradigm for the prevention of various diseases. This review aims to give an update on the sources as well as pharmacological profile of curcumol, a pharmacologically active sesquiterpenoid, which is an imperative bioactive constituent of several plants mainly from genus Curcuma. Curcumol has potential to fight against cancer, oxidative stress, neurodegeneration, microbial infections, and inflammation. Curcumol has been documented as potent inducer of apoptosis in numerous cancer cells via targeting key signaling pathways as MAPK/ERK, PI3K/Akt and NF-κB which are generally deregulated in several cancers. The reported data reveals multitarget activity of curcumol in cancer treatment suggesting its importance as anticancer drug in future. It is speculated that curcumol may provide an excellent opportunity for the cure of cancer but further investigations on mechanism of its action and preclinical trials are still mandatory to further validate the potential of this natural cancer killer in anticancer therapies.

Curcumin and Curcumol Inhibit NF-κB and TGF-β 1/Smads Signaling Pathways in CSE-Treated RAW246.7 Cells

E-Zhu (Curcuma zedoaria) is known as a classical traditional Chinese medicine and widely used in the treatment of cancers, cardiovascular disease, inflammation, and other diseases. Its main components include curcumol and curcumin, which have anti-inflammatory and antifibrosis effects. Here we established an in vitro inflammatory injury model by stimulating RAW246.7 cells with cigarette smoke extract (CSE) and detected the intervention effects of curcumin and curcumol on CSE-treated Raw246.7 macrophage cells to explore whether the two compounds inhibited the expression of inflammatory cytokines by inhibiting the NF-κB signaling pathway. We detected the antifibrosis effects of curcumin and curcumol via TGF-β₁/Smads signaling pathways. The model of macrophage damage group was established by CSE stimulation. Curcumol and curcumin were administered to Raw246.7 macrophage cells. The efficacy of curcumol and curcumin was evaluated by comparing the activation of proinflammatory factors, profibrotic factors, and NF-κB and TGF-β₁/Smads signaling pathway. In addition, CSE-treated group was employed to detect whether the efficacy of curcumol and curcumin was dependent on the NF-κB signaling via the pretreatment with the inhibitor of NF-κB. Our findings demonstrated that curcumol and curcumin could reduce the release of intracellular ROS from macrophages, inhibit the NF-κB signaling pathway, and downregulate the release of proinflammatory factor. Curcumol and curcumin inhibited the TGF-β₁/Smads signaling pathway and downregulated the release of fibrotic factors. Curcumin showed no anti-inflammatory effect in CSE-treated cells after the inhibition of NF-κB. Curcumol and curcumin showed an anti-inflammatory effect by inhibiting the NF-κB signaling pathway.

Graphene oxide regulates endoplasmic reticulum stress: autophagic pathways in nasopharyngeal carcinoma cells

During carcinogenesis, growth, proliferation, invasion and metastasis, increasing evidence shows that autophagy and endoplasmic reticulum stress (ER stress) are regulated in nasopharyngeal carcinoma, a finding drawing more attention from physicians and scientists. As one of the carbon-based nano-materials, graphene oxide (GO) has been extensively used for its advantages, such as biocompatibility, an ultrahigh surface to volume ratio, abundant surface groups, and a special photothermal effect. The present study is designed to explore the effects of GO on autophagy and ER stress in nasopharyngeal carcinoma cells. Our findings will provide scientific bases for the clinical application of GO and the development of new analogues. GO inhibits the proliferation of HONE1 cells, promotes their apoptosis in a concentration-dependent manner and enhances the expression of the ER stress chaperone GRP78 in HONE1 cells. These results suggest that GO could affect HONE1 cells through the autophagic and ER stress pathways. Thus, GO inhibits the proliferation of nasopharyngeal carcinoma cells via the induction of cytotoxic autophagy. In addition, ER stress is also activated as an adaptive response, so blocking ER stress may enhance the sensitivity of nasopharyngeal carcinoma cells to GO.