Guangwen Wu

An ultrasensitive electrochemical impedance sensor for a special BRCA1 breast cancer gene sequence based on lambda exonuclease assisted target recycling amplification

A label-free, target recycling electrochemical impedance spectroscopy (EIS) DNA sensor has been developed for detection of a model related to the BRCA1 breast cancer gene with a detection limit of 0.05 nM.

Scutellaria barbata D. Don induces G1/S arrest via modulation of p53 and Akt pathways in human colon carcinoma cells

Cancer cells are characterized by an uncontrolled increase in cell proliferation. G1 to S transition is one of the two main checkpoints used by cells to control the cell cycle progress and cell proliferation. G1/S progression is highly regulated by multiple intracellular signaling transduction cascades including Akt and p53 pathways, which therefore becomes a promising target for the development of novel anticancer therapy. Scutellaria barbata D. Don (SB) is a major component in many Chinese medicine formulas that have long been used in China to clinically treat various cancers including colorectal cancer (CRC). Recently, we reported that the ethanol extract of SB (EESB) is able to induce cancer cell apoptosis via activation of the mitochondrion-dependent pathway and inhibit tumor angiogenesis through suppression of Hedgehog signaling. To further elucidate the precise mechanisms of its antitumor activity, in the present study we evaluated the effect of EESB on the proliferation of human colon carcinoma HT-29 cells and investigated the underlying molecular mechanism. We found that EESB could inhibit the proliferation of HT-29 cells through blocking the G1/S cell cycle progression. In addition, EESB treatment profoundly promoted antiproliferative p21 expression, but inhibited the expression of pro-proliferative PCNA, cyclin D1 and CDK4 in HT-29 cells. Moreover, the phosphorylation/activation of Akt was significantly suppressed by EESB treatment, whereas that of p53 was enhanced. These results suggest that EESB could effectively induce G1/S arrest in human colon carcinoma cells via modulation of multiple cell cycle-related signaling pathways.

Total alkaloids of Rubus aleaefolius Poir inhibit hepatocellular carcinoma growth in vivo and in vitro via activation of mitochondrial-dependent apoptosis

The aim of this study was to evaluate the therapeutic efficacy of Rubus aleaefolius Poir total alkaloids (TARAP) against hepatocellular carcinoma growth in vivo and in vitro, and to investigate the possible molecular mechanisms mediating its biological activity. Nude mice were implanted with HepG2 human hepatocellular carcinoma cells and fed with vehicle (physiological saline) or 3 g/kg/d dose of TARAP, 5 days per week, for 21 days. The in vivo efficacy of TARAP against tumor growth was investigated by evaluating its effect on tumor volume and tumor weight in mice with HCC xenografts and its adverse effect was determined by measuring the body weight gain. The in vitro effect of TARAP on the viability of HepG2 cells was determined by MTT assay. HepG2 cell morphology was observed via phase-contrast microscopy. Apoptosis in tumor tissues or in HepG2 cells was analyzed by TUNEL assay or FACS analysis with Annexin V/PI, respectively. The loss of mitochondrial membrane potential in HepG2 cells was determined via JC-1 staining followed by FACS analysis. Activation of caspase-9 and -3 in HepG2 cells was examined by a colorimetric assay. The mRNA and protein expression of Bcl-2 and Bax in tumor tissues were measured by RT-PCR and immunohistochemistry. TARAP reduced tumor volume and tumor weight, but had no effect on the body weight gain in HCC mice. TARAP decreased the viability of HepG2 cells and induced cell morphological changes in vitro in a dose- and time-dependent manner. In addition, TARAP induced apoptosis both in tumor tissues and in HepG2 cells. Moreover, TARAP treatment resulted in the collapse of mitochondrial membrane potential in HepG2 cells, as well as the activation of caspase-9 and -3. Furthermore, administration of TARAP increased the pro-apoptotic Bax/Bcl-2 ratio in HCC mouse tumors, at both transcriptional and translational levels. TARAP inhibits hepatocellular carcinoma growth both in vivo and in vitro probably through the activation of mitochondrial-dependent apoptosis, which may, in part, explain its anticancer activity. These results suggest that total alkaloids in Rubus aleaefolius Poir may be a potential novel therapeutic agent for the treatment of hepatocellular carcinoma and other cancers.

In vitro study of inhibitory millimeter wave treatment effects on the TNF-α-induced NF-κB signal transduction pathway

Abnormal activation of the nuclear factor-κB (NF-κB) in chondrocytes initiates the transcription of inflammatory mediators, promotes their generation and release, and amplifies initial inflammatory signals. This results in the release of chondral matrix-degrading enzymes and accelerates the degeneration of articular cartilage. As a non-pharmaceutical and non-invasive physical therapy regimen, millimeter wave treatment has been successfully used for the treatment of osteoarthritis. In this study, chondrocytes were derived from the cartilages of knee joints of 4-week-old male Sprague-Dawley rats and were mechanically digested by collagenase type II treatment for further culture in vitro. The third-passage chondrocytes were stained with toluidine blue and treated with a gradient of tumor necrosis factor-α (TNF-α) for various times. Chondrocytic activity was measured by MTT assay, and the apoptotic rate of the chondrocytes was determined with Hocehst 33342 staining to identify effective treatment concentrations and durations and to establish an apoptosis model for the chondrocytes in response to TNF-α. Using this model, the chondrocytes were randomly divided to receive millimeter wave treatment for various times. The apoptotic rate of the chondrocytes was measured by Annexin V-FITC staining and the protein expression levels of RIP, TAK1, IκB kinase (IKK)-ß, IκB-α and NF-κB, were determined by Western blotting. Chondrocytic structure was examined by transmission electronic microscopy. The apoptotic rates were significantly lower at 4 and 8 h of treatment than at 0 and 2 h. The expression levels of RIP, TAK1, IKK-ß and NF-κB were also significantly lower at 4 and 8 h than at 0 and 2 h, whereas that of IκB-α was significantly higher at 4 and 8 h than at 0 and 2 h. Therefore, we can conclude that millimeter wave treatment can inhibit the activation of the TNF-α-mediated NF-κB signal transduction pathway through the down-regulation of RIP, TAK1, IKK-ß and NF-κB, and the up-regulation of IkB-α, in chondrocytes.

Duhuo Jisheng Decoction promotes chondrocyte proliferation through accelerated G1/S transition in osteoarthritis

Duhuo Jisheng Decoction (DHJSD), a well known traditional Chinese folk medicine, is used for eliminating stagnation, removing blood stasis, promoting blood circulation and alleviating pain; it is commonly used for the treatment of various diseases, including osteoarthritis (OA). However, the molecular mechanisms behind the therapeutic effects of OA remain unclear. In the present study, the effects of DHJSD on the morphology of articular cartilage and the G1/S cell cycle progression in chondrocytes, as well as the underlying mechanisms, were investigated. A total of 27 two‑month‑old male Sprague Dawley rats were randomly divided into 3 groups: the control group (no papain-induced OA; received an equivalent amount of saline only), the model group (papain-induced OA; received an equivalent amount of saline only) and the DHJSD group [papain-induced OA; received a clinical oral dose of DHJSD (9.3 g/kg/day)]. After 8 consecutive weeks of treatment, the morphological changes in articular cartilage were observed under an optical microscope and by transmission electron microscopy (TEM) and the mRNA and protein expression levels of cyclin D1, CDK4, CDK6, retinoblastoma protein (Rb) and p16 were measured by RT‑PCR and immunohistochemistry, respectively. Treatment with DHJSD significantly improved the arrangement of collagen fibers in the articular cartilage, as well as its structure and reduced cell degeneration compared with the model group. The mRNA and protein expression levels of cyclin D1, CDK4, CDK6 and Rb in the DHJSD‑treated group were significantly increased compared with those in the model group, whereas p16 expression was significantly downregulated. Taken together, these results indicate that DHJSD treatment promotes chondrocyte proliferation by promoting the G1/S checkpoint transition in the cell cycle and by upregulating the expression of cyclin D1, CDK4, CDK6 and Rb and downregulating the expression of p16 and this may, in part, explain its clinical efficacy in the treatment of osteoarthritis.

Millimeter wave radiation induces apoptosis via affecting the ratio of Bax/Bcl-2 in SW1353 human chondrosarcoma cells.

The efficacy and safety of millimeter wave radiation has been proven for various types of malignant tumors. However, the mechanisms underlying effects of millimeter wave radiation on apoptosis are still unclear. The present study was undertaken to examine the effects of millimeter wave radiation on cell apoptosis and mitochondrial membrane potential, and to determine the molecular mechanism of millimeter wave radiation-induced apoptosis by investigating the expression of Bcl-2 family proteins (Bcl-2, Bax), caspase-9 and caspase-3 in SW1353 cells. We found that millimeter wave radiation suppressed the viability of SW1353 cells, demonstrating that millimeter wave radiation induced cell apoptosis and reduced cell viability in a time-dependent manner. Furthermore, we observed that treatment of cells with millimeter wave radiation significantly induced loss of mitochondrial membrane potential, upregulated proapoptotic Bax, caspase-9 and caspase-3, but did not significantly change levels of antiapoptotic Bcl-2. These data suggested that millimeter wave radiation may induce apoptosis via affecting the ratio of Bax/Bcl-2 in SW1353 cells.

Millimeter wave treatment promotes chondrocyte proliferation via G1/S cell cycle transition

Millimeter waves, high-frequency electromagnetic waves, can effectively alleviate the clinical symptoms in osteoarthritis patients, as a non-pharmaceutical and non-invasive physical therapy regimen. However, the molecular mechanisms of the therapeutic effects of millimeter wave treatment are not well understood. In the present study, the effect of millimeter waves on the G1/S cell cycle progression in chondrocytes and the underlying mechanism was investigated. Chondrocytes isolated from the knee of SD rats were cultured and identified using toluidine blue staining. The second generation chondrocytes were collected and stimulated with or without millimeter waves for 48 h. Chondrocyte viability was analyzed using the MTT assay. The cell cycle distribution of chondrocytes was analyzed by flow cytometry. mRNA and protein expression levels of cyclin D1, cyclin-dependent kinases 4 and 6 (CDK4 and CDK6) and p21 were detected using real-time PCR and western blotting, respectively. Millimeter wave stimulation was found to significantly enhance chondrocyte viability. Moreover, the percentage of chondrocytes in the G0/G1 phase was significantly decreased, whereas that in the S phase was significantly increased. In addition, following millimeter wave treatment, cyclin D1, CDK4 and CDK6 expression was significantly upregulated, whereas p21 expression was significantly downregulated. The results indicate that millimeter wave treatment promotes chondrocyte proliferation via cell cycle progression.

Experimental study of low-frequency electroacupuncture-induced differentiation of bone marrow mesenchymal stem cells into chondrocytes.

In the present study, we investigated the effect of low-frequency electroacupuncture (EA) on the differentiation of bone mesenchymal stem cells (BMSCs) into chondrocytes and the molecular mechanism involved. We isolated BMSCs from Sprague-Dawley (SD) rat bone marrow. Third-generation SD rat BMSCs (P3 BMSCs) were harvested and characterized by flow cytometry with FITC staining. Data indicated that the positive rates of CD90 and CD45 were 98.22 and 1.91%, respectively, indicating the high purity of the BMSCs. The P3 BMSCs were treated with EA for 15 or 30 min daily for 7 or 14 days. Using optical microscopy and transmission electron microscopy, we found that EA induced morphological changes in the BMSCs, displaying typical morphology of early chondrocytes. In addition, we found that the cytoplasm and extracellular matrices were metachromatically stained by toluidine blue in the treated cells in a dose-dependent manner, indicating that EA treatment resulted in the expression of glycosaminoglycan. Furthermore, upon immunohistocytochemical staining and Western blotting, we found that EA treatment significantly and dose-dependently induced expression of chondrocyte-specific matrix protein type II collagen, which may have been mediated by the transcription factor Sox9, as the mRNA expression of Sox9 was found to be significantly increased after EA treatment. Taken together, these results suggest that EA can be employed as a novel non-drug-inducing method for the differentiation of BMSCs into chondrocytes.

Xiao Jin Wan, a traditional Chinese herbal formula, inhibits proliferation via arresting cell cycle progression at the G2/M phase and promoting apoptosis via activating the mitochondrial‑dependent pathway in U-2OS human osteosarcoma cells

Xiao Jin Wan (XJW) is a well-known traditional Chinese folk-medicine, which is commonly used for the treatment of various types of diseases including cancers. However, the mechanism of the anticancer activity of XJW against U-2OS human osteosarcoma cells, have not yet been reported. In the present study, we investigated the cellular effects of the XJW on the U-2OS human osteosarcoma cell line. Our results showed that XJW induced cell morphological changes, reduced cell viability in a dose- and time-dependent manner and arrested in the G2/M phase of the cell cycle suggesting that XJW inhibited the proliferation of U-2OS cells. Hoechst 33258 staining and Annexin V/propidium iodide double staining exhibited the typical nuclear features of apoptosis and increased the proportion of apoptotic Annexin V-positive cells in a dose-dependent manner, respectively. In addition, XJW treatment caused loss of plasma membrane asymmetry, collapse of mitochondrial membrane potential, activation of caspase-9 and caspase-3, and increase of the ratio of pro-apoptotic Bax to anti-apoptotic Bcl-2. Taken together, the results indicate that the U-2OS cell growth inhibitory activity of XJW was due to cell cycle arrested and mitochondrial-mediated apoptosis, which may partly explain the anticancer activity of Xiao Jin Wan.

Millimeter wave treatment inhibits the mitochondrion-dependent apoptosis pathway in chondrocytes

Millimeter wave (MW) is an electromagnetic wave with a wavelength between 1 and 10 mm and a frequency of 30-300 GHz that causes multiple biological effects, both locally and globally. MW has been widely used in clinical medicine. Although our previous work demonstrated that MW is capable of inhibiting sodium nitroprussiate (SNP)-induced apoptosis in chondrocytes, the precise mechanism of the anti-apoptotic activity remains to be elucidated. The purpose of this study was to investigate the effects of MW in SNP-induced apoptotic chondrocytes. Sprague Dawley rat chondrocytes were isolated and cultured, and the cells were counted. Cell viability was evaluated using MTT assay. Cells were then treated with SNP and MW, and flow cytometry was used to detect apoptosis. Our results showed that MW treatment inhibited a SNP-induced mitochondrion-dependent pathway of apoptosis. MW treatment inhibited the loss of plasma membrane asymmetry (externalization of phosphatidylserine), collapse of mitochondrial membrane potential, and activation of caspase-9 and caspase-3. Taken together, the results indicate that MW inhibits the mitochondrion-dependent pathway of apoptosis in chondrocytes and this may, in part, explain its clinical effect in the treatment of osteoarthritis.