Xuanbin Wang

Id-1 expression and cell survival

The Id (inhibitor of differentiation or DNA binding) helix-loop-helix (HLH) proteins are a group of dominant negative regulators of basic HLH transcriptional factors which promote cell differentiation. Recent evidence has revealed that Id proteins, especially Id-1, are also able to promote cell proliferation and cell cycle progression through inactivation of tumour suppressor and activation of growth promoting pathways in mammalian cells. In addition, upregulation of Id-1 has been found in many types of human cancer and its expression levels are also associated with advanced tumour stage. Furthermore, ectopic expression of Id-1 in human cancer cells is able to induce cell proliferation under sub-optimal conditions and protect the cells against apoptosis. These lines of evidence strongly indicate Id-1 as a positive regulator of cell growth and its expression may be a key factor required for tumour cell proliferation. This review will discuss recent evidence on the role of Id-1 in cell proliferation and survival, and its significance in malignant transformation. In addition, we will highlight the recent development in the understanding of the molecular mechanisms responsible for the action of Id-1 in promoting cell survival and tumourigenesis. Finally, the therapeutic implications through inactivation of Id-1 in the treatment of human cancer will also be addressed.

Down-regulation of Id-1 expression is associated with TGFβ1-induced growth arrest in prostate epithelial cells

Transforming growth factor beta1 (TGF beta 1) plays important roles in the regulation of cell growth and differentiation in both normal and malignant prostate epithelial cells. Although certain pathways have been suggested, the mechanisms responsible for the action of TGF beta 1 are not well understood. In the present study, using a human papilloma virus 16 E6/E7 immortalized prostate epithelial cell line, HPr-1, we report that TGF beta 1 was able to suppress the expression of Id-1, a helix-loop-helix (HLH) protein, which plays important roles in the inhibition of cell differentiation and growth arrest. In addition, a decrease at both Id-1 mRNA and protein expression levels was associated with TGF beta 1-induced growth arrest and differentiation, indicating that Id-1 may be involved in TGF beta 1 signaling pathway. The fact that up-regulation of p21(WAF1), one of the downstream effectors of Id-1, was observed after exposure to TGF beta 1 further indicates the involvement of Id-1 in the TGF beta 1-induced growth arrest in HPr-1 cells. However, increased expression of p27(KIP1) was also observed in the TGF beta 1-treated cells, suggesting that in addition to down-regulation of Id-1, other factors may be involved in the TGF beta 1-induced cell growth arrest and differentiation in prostate epithelial cells. Our results provide evidence for the first time that TGF beta 1 may be one of the upstream regulators of Id-1.

The Reactive Oxygen Species in Macrophage Polarization: Reflecting Its Dual Role in Progression and Treatment of Human Diseases

High heterogeneity of macrophage is associated with its functions in polarization to different functional phenotypes depending on environmental cues. Macrophages remain in balanced state in healthy subject and thus macrophage polarization may be crucial in determining the tissue fate. The two distinct populations, classically M1 and alternatively M2 activated, representing the opposing ends of the full activation spectrum, have been extensively studied for their associations with several disease progressions. Accumulating evidences have postulated that the redox signalling has implication in macrophage polarization and the key roles of M1 and M2 macrophages in tissue environment have provided the clue for the reasons of ROS abundance in certain phenotype. M1 macrophages majorly clearing the pathogens and ROS may be crucial for the regulation of M1 phenotype, whereas M2 macrophages resolve inflammation which favours oxidative metabolism. Therefore how ROS play its role in maintaining the homeostatic functions of macrophage and in particular macrophage polarization will be reviewed here. We also review the biology of macrophage polarization and the disturbance of M1/M2 balance in human diseases. The potential therapeutic opportunities targeting ROS will also be discussed, hoping to provide insights for development of target-specific delivery system or immunomodulatory antioxidant for the treatment of ROS-related diseases.

Berberine-induced tumor suppressor p53 up-regulation gets involved in the regulatory network of MIR-23a in hepatocellular carcinoma

AIM OF THE STUDY To investigate the involvement of p53 in the regulatory network of microRNA-23a (miR-23a) in berberine-treated hepatocellular carcinoma (HCC) cells. METHODS The biogenesis of miR-23a upon berberine treatment was monitored by detecting the transcript expression of primary precursor, precursor and mature forms of miR-23a. Protein expression was detected with immunoblotting. The binding capacity between p53 and chromatin DNA was determined by chromatin immunoprecipitation. The role of miR-23a in mediating suppression of HCC by berberine was determined both in vitro and in vivo. RESULTS miR-23a was up-regulated upon berberine treatment in human HCC cells, and berberine could increase the expression of primary precursor, precursor and mature forms of miR-23a. The up-regulation of miR-23a by berberine is p53-dependent. Inhibition of p53 expression and activity could block the up-regulation of miR-23a induced by berberine. Furthermore, berberine-induced miR-23a expression may mediate the transcription activation of p53-related tumor suppressive genes p21 and GADD45α. Inhibition of miR-23a abolishes the binding of p53 onto chromatin and attenuates transcription activation of p21 and GADD45α. Target prediction and experimental validation demonstrate that berberine-induced miR-23a may target to Nek6 to suppress its expression. Berberine-induced G2/M cell cycle arrest in HCC was attenuated when miR-23a was inhibited. Berberine-induced cell death and in vivo tumor growth inhibition are attenuated upon inhibition of miR-23a. CONCLUSION Our study reveals that miR-23a may be involved in regulating the anti-HCC effect of berberine by mediating the regulation of p53.

Chinese Medicines Induce Cell Death: The Molecular and Cellular Mechanisms for Cancer Therapy

Chinese medicines have long history in treating cancer. With the growing scientific evidence of biomedical researches and clinical trials in cancer therapy, they are increasingly accepted as a complementary and alternative treatment. One of the mechanisms is to induce cancer cell death. Aim. To comprehensively review the publications concerning cancer cell death induced by Chinese medicines in recent years and provide insights on anticancer drug discovery from Chinese medicines. Materials and Methods. Chinese medicines (including Chinese medicinal herbs, animal parts, and minerals) were used in the study. The key words including “cancer”, “cell death”, “apoptosis”, “autophagy,” “necrosis,” and “Chinese medicine” were used in retrieval of related information from PubMed and other databases. Results. The cell death induced by Chinese medicines is described as apoptotic, autophagic, or necrotic cell death and other types with an emphasis on their mechanisms of anticancer action. The relationship among different types of cell death induced by Chinese medicines is critically reviewed and discussed. Conclusions. This review summarizes that CMs treatment could induce multiple pathways leading to cancer cell death, in which apoptosis is the dominant type. To apply these preclinical researches to clinic application will be a key issue in the future.

A comparative study on the hepatoprotective action of bear bile and Coptidis Rhizoma aqueous extract on experimental liver fibrosis in rats.

Aim of the studyBear bile and Coptidis Rhizoma have been used in Chinese medicine with a long tradition in treating heat-diseases. Both bear bile and Coptidis Rhizoma are used to treat liver diseases in clinical practice of Chinese Medicine. Since bears are currently endangered, it raises the question whether the use of bear bile is ethical. To look for substitute for bear bile, the aim of this study is to compare the anti-fibrotic effects of Coptidis Rhizoma and its major component berberine with the actions of bear bile and its major compound tauroursodeoxycholic acid on experimental liver fibrosis in rats.MethodQuality assessment was conducted with high performance liquid chromatography. The experimental liver fibrosis in rats was induced by carbon tetrachloride, alcohol, and bile duct ligation respectively. The biochemical criteria in the blood and tissue samples were measured to evaluate the anti-fibrotic properties and underlying mechanisms of the drugs.ResultsCoptidis Rhizoma Aqueous Extract (CRAE), berberine, and bear bile exerted anti-fibrotic properties on various liver fibrosis models in rats. CRAE and berberine significantly reduced the peroxidative stress in liver through increasing the superoxide dismutase enzyme activity. CRAE and berberine were able to excrete bilirubin products from the liver and protect hepatocytes from cholestatic damage. The effect of CRAE and berberine are comparable to that of bear bile.ConclusionInstead of using bear bile, CRAE and berberine can be potential substitutes in treating liver fibrosis.

Chinese Medicines as an Adjuvant Therapy for Unresectable Hepatocellular Carcinoma during Transarterial Chemoembolization: A Meta-Analysis of Randomized Controlled Trials

Objective. To conduct a comprehensive PRISMA-compliant systematic review and meta-analysis to evaluate the efficacy and safety of Chinese medicines (CMs) as an adjuvant therapy for unresectable HCC during transarterial chemoembolization (TACE). Methods. Main databases were searched up to October 2012 for randomized controlled trials (RCTs) evaluating the effects of CMs plus TACE on unresectable HCC compared with TACE alone. References of relevant reviews and eligible studies were also assessed. Risk ratios with 95% confidence intervals and mean difference were calculated. Heterogeneity and publication bias were examined. Results. Sixty-seven trials (N = 5,211) were included in the meta-analysis. Sensitivity analysis and random-effects model were performed for assessing significant heterogeneity. CMs plus TACE showed beneficial effects on tumor response, survival at 6, 12, 18, 24, and 36 months, quality of life, and TACE toxicity reduction compared with TACE alone. Conclusion. The results show that the use of CMs may increase the efficacy and reduce the toxicity of TACE in treating patients with unresectable HCC. These findings suggest that CMs could be considered as an adjuvant therapy for unresectable HCC patients during TACE. Larger-scale RCTs using standard methods and long-term follow-up are warranted to confirm these findings.

Recent progress on anti-liver fibrosis candidates in patents of herbal medicinal products.

Liver fibrosis is a common cause of chronic failure of liver function, which is characterized by extracellular matrix accumulation and disruption of normal tissue architecture. Liver fibrosis-dependent mechanisms of hepatocarcinogenesis have drawn much attention. Herbal medicines are one of the strategies against liver fibrosis and a way to prevent hepatocellular carcinoma (HCC). Herbal medicines are usually used as official drugs in China, Japan and other parts of Asia. In this review, we retrieved and summarized current progress of anti-liver fibrosis candidates in USA, European and worldwide patents of herbal medicines in recent ten years. The pure compounds, fractions in single herbs and composite formulae were analyzed and discussed. The results indicated that herbal medicinal products can have potential on antiliver fibrosis. Further studies should focus on the structure modification of natural compound by computer-assisted drug design, quality control by acceptable worldwide guidelines, and mechanisms of action, drug metabolism and translational research.

A Chinese medicine formula Gegen Qinlian decoction suppresses expansion of human renal carcinoma with inhibition of matrix metalloproteinase-2.

Aim of Study. Gegen Qinlian decoction (GQLD) is an ancient Chinese medicine formula for treating diseases with inner heat. The aim of this study is to investigate the antitumor effect of GQLD in human renal carcinoma cell (RCC) and its possible mechanism. Method. High-performance liquid chromatography was used to identify and quantify active compounds in GQLD. Inhibition of tumor growth was determined by xenograft model. Cell viability on treatment with the decoction was determined by MTT assay; quantitative real-time polymerase chain reaction and immunoblotting were used to determine gene and protein expression; matrix metalloproteinase-2 (MMP-2) activity was detected by gelatin zymography and in vitro enzymatic reaction assay. Results. Thirteen major peaks were detected in the decoction, 8 of which were identified as berberine, baicalin and baicalein, pueranin, daizidin, liquiritin, wogonoside, and wogonin. GQLD exhibited potent inhibition on xenografted expansion of RCC cells. Interestingly, GQLD treatment did not induce cell death to RCC cells, but blocked the neoangiogenesis in xenografted RCC tumor. Particularly, we found that GQLD significantly inhibited MMP-2 in RCC cells, which was involved as a critical factor in avascular growth of RCC. GQLD directly suppressed the enzyme activity of MMP-2. Radix Scutellariae was the major herbal component that contributed to the potent inhibition of MMP-2. Conclusion. The findings of this study provide experimental evidence of the inhibition of expansion and neoangiogenesis of renal carcinoma by Chinese medicine formula GQLD with involvement of MMP-2 suppression.

Deciphering hepatocellular carcinoma through metabolomics: from biomarker discovery to therapy evaluation

Hepatocellular carcinoma (HCC) is the third most common cause of death from cancer, with increasing prevalence worldwide. The mortality rate of HCC is similar to its incidence rate, which reflects its poor prognosis. At present, the diagnosis of HCC is still mostly dependent on invasive biopsy, imaging methods, and serum α-fetoprotein (AFP) testing. Because of the asymptomatic nature of early HCC, biopsy and imaging methods usually detect HCC at the middle–late stages. AFP has limited sensitivity and specificity, as many other nonmalignant liver diseases can also result in a very high serum level of AFP. Therefore, better biomarkers with higher sensitivity and specificity at earlier stages are greatly needed. Since metabolic reprogramming is an essential hallmark of cancer and the liver is the metabolic hub of living systems, it is useful to investigate HCC from a metabolic perspective. As a noninvasive and nondestructive approach, metabolomics provides holistic information on dynamically metabolic responses of living systems to both endogenous and exogenous factors. Therefore, it would be conducive to apply metabolomics in investigating HCC. In this review, we summarize recent metabolomic studies on HCC cellular, animal, and clinicopathologic models with attention to metabolomics as a biomarker in cancer diagnosis. Recent applications of metabolomics with respect to therapeutic and prognostic evaluation of HCC are also covered, with emphasis on the potential of treatment by drugs from natural products. In the last section, the current challenges and trends of future development of metabolomics on HCC are discussed. Overall, metabolomics provides us with novel insight into the diagnosis, prognosis, and therapeutic evaluation of HCC.