Wenfeng Zeng

Naringenin Decreases Invasiveness and Metastasis by Inhibiting TGF-β-Induced Epithelial to Mesenchymal Transition in Pancreatic Cancer Cells

Epithelial to mesenchymal transition (EMT) promotes cellular motility, invasiveness and metastasis during embryonic development and tumorigenesis. Transforming growth factor-β (TGF-β) signaling pathway is a key regulator of EMT. A lot of evidences suggest that this process is Smad3-dependent. Herein we showed that exposure of aspc-1 and panc-1 pancreatic cancer cells to TGF-β1 resulted in characteristic morphological alterations of EMT, and enhancement of cell motility and gemcitabine (Gem) resistance along with an up-regulation of EMT markers genes such as vimentin, N-cadherin, MMP2 and MMP9. Naringenin (Nar) down-regulated EMT markers expression in both mRNA and protein levels by inhibiting TGF-β1/Smad3 signal pathway in the pancreatic cancer cells. Consequently, Nar suppressed the cells migration and invasion and reversed their resistance to Gem.

Chrysin promotes osteogenic differentiation via ERK/MAPK activation

The effect of the anti-inflammatory flavonoid chrysin on osteogenesis was determined in preosteoblast MC3T3-E1 cells. Results demonstrated that chrysin could induce osteogenic differentiation in the absence of other osteogenic agents. Chrysin treatment promoted the expression of transcription factors (Runx2 and Osx) and bone formation marker genes (Col1A1, OCN, and OPN) as well as enhanced the formation of mineralized nodules. During osteogenic differentiation, chrysin preferentially activated ERK1/2, but not JNK nor the p38 MAPKs. Further experiments with inhibitors revealed the co-treatment of U0126, PD98059, or ICI182780 (a general ER antagonist) with chrysin effectively abrogated the chrysin-induced osteogenesis and ERK1/2 activation. Thus, the effect of chrysin on osteogenesis is ERK1/2-dependent and involves ER. Therefore, chrysin has the significant potential to enhance osteogenesis for osteoporosis prevention and treatment.

Naringenin prevents TGF-β1 secretion from breast cancer and suppresses pulmonary metastasis by inhibiting PKC activation

BackgroundTargeting the TGF-β1 pathway for breast cancer metastasis therapy has become an attractive strategy. We have previously demonstrated that naringenin significantly reduced TGF-β1 levels in bleomycin-induced lung fibrosis and effectively prevented pulmonary metastases of tumors. This raised the question of whether naringenin can block TGF-β1 secretion from breast cancer cells and inhibit their pulmonary metastasis.MethodsWe transduced a lentiviral vector encoding the mouse Tgf-β1 gene into mouse breast carcinoma (4T1-Luc2) cells and inoculated the transformant cells (4T1/TGF-β1) into the fourth primary fat pat of Balb/c mice. Pulmonary metastases derived from the primary tumors were monitored using bioluminescent imaging. Spleens, lungs and serum (n = 18–20 per treatment group) were analyzed for immune cell activity and TGF-β1 level. The mechanism whereby naringenin decreases TGF-β1 secretion from breast cancer cells was investigated at different levels, including Tgf-β1 transcription, mRNA stability, translation, and extracellular release.ResultsIn contrast to the null-vector control (4T1/RFP) tumors, extensive pulmonary metastases derived from 4T1/TGF-β1 tumors were observed. Administration of the TGF-β1 blocking antibody 1D11 or naringenin showed an inhibition of pulmonary metastasis for both 4T1/TGF-β1 tumors and 4T1/RFP tumors, resulting in increased survival of the mice. Compared with 4T1/RFP bearing mice, systemic immunosuppression in 4T1/TGF-β1 bearing mice was observed, represented by a higher proportion of regulatory T cells and myeloid-derived suppressor cells and a lower proportion of activated T cells and INFγ expression in CD8+ T cells. These metrics were improved by administration of 1D11 or naringenin. However, compared with 1D11, which neutralized secreted TGF-β1 but did not affect intracellular TGF-β1 levels, naringenin reduced the secretion of TGF-β1 from the cells, leading to an accumulation of intracellular TGF-β1. Further experiments revealed that naringenin had no effect on Tgf-β1 transcription, mRNA decay or protein translation, but prevented TGF-β1 transport from the trans-Golgi network by inhibiting PKC activity.ConclusionsNaringenin blocks TGF-β1 trafficking from the trans-Golgi network by suppressing PKC activity, resulting in a reduction of TGF-β1 secretion from breast cancer cells. This finding suggests that naringenin may be an attractive therapeutic candidate for TGF-β1 related diseases.

Vitamin C induces periodontal ligament progenitor cell differentiation via activation of ERK pathway mediated by PELP1

The differentiation of periodontal ligament (PDL) progenitor cells is important for maintaining the homeostasis of PDL tissue and alveolar bone. Vitamin C (VC), a water-soluble nutrient that cannot be biosynthesized by humans, is vital for mesenchymal stem cells differentiation and plays an important role in bone remodeling. Therefore, the objective of this study was to determine the function and mechanism of VC in PDL progenitor cells osteogenic differentiation at the molecular level. We demonstrated that VC could induce the osteogenic differentiation and maturation of PDL progenitor cell without other osteogenic agents. During the process, VC preferentially activated ERK1/2 but did not affect JNK or p38. Co-treatment with ERK inhibitor effectively decreased the Vitamin C-induced expression of Runx2. ERK inhibitor also abrogated Vitamin C-induced the minimized nodules formation. PELP1, a nuclear receptor co-regulator, was up-regulated under VC treatment. PELP1 knockdown inhibited ERK phosphorylation. The overexpression of PELP1 had a positive relationship with Runx2 expression. Taken together, we could make a conclude that VC induces the osteogenic differentiation of PDL progenitor cells via PELP1-ERK axis. Our finding implies that VC may have a potential in the regeneration medicine and application to periodontitis treatment.

Stability influences the biodistribution, toxicity, and anti-tumor activity of doxorubicin encapsulated in PEG-PE micelles in mice.

ABSTRACTPurposeTo investigate the influences of stability of doxorubicin (DOX) retained in PEG-PE/HSPC micelles on its biodistribution, toxicity and anti-tumor activity in mice.MethodsWe incorporated HSPC into PEG-PE micelles at various molar ratios by a self-assembly procedure. Micelles were characterized by dynamic light scattering, transmission electron microscope, atomic force microscopy. Agarose gel electrophoresis assay was used to detect stable retention of DOX in micellar preparations. Biodistribution, toxicity and anti-tumor activity of doxorubicin encapsulated in PEG-PE/HSPC micelles in mice were investigated.ResultsHSPC incorporation not only changed the size and shape of PEG-PE micelles, but also decreased the ability of DOX stable retained in PEG-PE micelles, resulting in a great discrepancy in biodistribution, toxicity and anti-tumor activity among micellar DOX preparations. DOX encapsulated in PEG-PE micelles (M1-DOX), with narrower size distribution and greater stability, demonstrated better cytotoxicity in vitro and low systemic toxicity with superior anti-tumor metastasis activity in vivo.ConclusionsEncapsulation of DOX into PEG-PE micelles showed the best therapeutic activity and lowest systemic toxicity compared to other HSPC-incorporated PEG-PE micellar preparations. Stable retention of drugs within micelles is important and is determined by compatibility between drugs and polymer blocks.

Naringenin Ameliorates Acute Inflammation by Regulating Intracellular Cytokine Degradation

Ungoverned activation of innate and adaptive immunity results in acute inflammatory disease, such as bacteria-induced endotoxemia and fulminant hepatitis by virus infection. Thus, therapeutic control of inflammation is crucial for clinical management of many human diseases. In murine models of LPS- and Con A–induced liver injury, we found that naringenin, a natural predominant flavanone, is capable of protecting against lethality induced by LPS and preventing inflammation-induced organ injury. The protective effect of naringenin is mediated by reducing the levels of several inflammatory cytokines. Unexpectedly, naringenin inhibits TNF-α and IL-6 secretion in macrophages and T cells without interfering with the TLR signaling cascade, cytokine mRNA stability, or protein translation. These results indicate the existence of a posttranslational control mechanism. Further studies show that naringenin enhances intracellular cytokine degradation through lysosome- and TFEB-dependent mechanisms. This study provides evidence that naringenin has the capacity to dampen cytokine production by regulating lysosome function. Thus, naringenin may represent a potential therapeutic agent for controlling inflammation-related diseases.

Naringenin Ameliorates Radiation-Induced Lung Injury by Lowering IL-1βLevel

Radiation-induced lung injury (RILI) is the main complication of radiotherapy for thoracic malignancies. Since naringenin, a potent immune-modulator, has been found to relieve bleomycin-induced lung fibrosis by restoring the balance of disordered cytokines, we sought to determine whether naringenin would mitigate RILI and to investigate the underlying mechanism. Animals received fractionated irradiation in the thoracic area to induce RILI. Enzyme-linked immunosorbent assay and MILLIPLEX assays were used for serum and bronchoalveolar lavage fluid for cytokine analyses, hematoxylin and eosin staining for pathologic changes, and Masson trichrome staining for determination of lung fibrosis. Interleukin (IL)-1β was found significantly elevated after thoracic irradiation and it triggered production of profibrotic tumor growth factor β both in vivo and in vitro, suggesting the vital role of in IL-1β in the development of RILI. Furthermore, we found that naringenin was able to ameliorate RILI through downregulation of IL-1β and restoration of the homeostasis of inflammatory factors. Our results demonstrated that naringenin could serve as a potent immune-modulator to ameliorate RILI. More importantly, we suggest that a new complementary strategy of maintaining the homeostasis of inflammatory factors combined with radiation could improve the efficacy of thoracic radiotherapy.

Naringenin as a potential immunomodulator in therapeutics

Naringenin, a citrus flavonoid that possesses various biological activities, has emerged as a potential therapeutic agent for the management of a variety of diseases. Studies using cell culture system have shown that naringenin can inhibit inflammatory response in diverse cell types. Moreover, research using various animal models has further demonstrated therapeutic potentials of naringenin in the treatment of several inflammation-related disorders, such as sepsis, fulminant hepatitis, fibrosis and cancer. The mechanism of action of naringenin is not completely understood but recent mechanistic studies revealed that naringenin suppresses inflammatory cytokine production through both transcriptional and post-transcriptional mechanisms. Surprisingly, naringenin not only inhibits cytokine mRNA expression but also promotes lysosome-dependent cytokine protein degradation. This unique property of naringenin stands in sharp contrast with some widely-studied natural products such as apigenin and curcumin, which regulate cytokine production essentially at the transcriptional level. Therefore, naringenin may provide modality for the development of novel anti-inflammatory agent. This review article summarizes our recent studies in understanding how naringenin acts in cells and animal models. Particularly, we will discuss the anti-inflammatory activities of naringenin in various disease context and its potential use, as an immunomodulator, in the treatment of inflammatory related disease.