A bioactive calcium silicate nanowire-containing hydrogel for organoid formation and functionalization.

Organoids, which are 3D multicellular constructs, have garnered significant attention in recent years. Existing organoid culture methods predominantly utilize natural and synthetic polymeric hydrogels. This study explored the potential of a composite hydrogel mainly consisting of calcium silicate (CS) nanowires and methacrylated gelatin (GelMA) as a substrate for organoid formation and functionalization, specifically for intestinal and liver organoids. Furthermore, the research delved into the mechanisms by which CS nanowires promote the structure formation and development of organoids. It was discovered that CS nanowires can influence the stiffness of the hydrogel, thereby regulating the expression of the mechanosensory factor yes-associated protein (YAP). Additionally, the bioactive ions released by CS nanowires in the culture medium could accelerate Wnt/ß-catenin signaling, further stimulating organoid development. Moreover, bioactive ions were found to enhance the nutrient absorption and ATP metabolic activity of intestinal organoids. Overall, the CS/GelMA composite hydrogel proves to be a promising substrate for organoid formation and development. This research suggested that inorganic biomaterials hold significant potential in organoid research, offering bioactivities, biosafety, and cost-effectiveness.

A multifunctional anti-inflammatory drug that can specifically target activated macrophages, massively deplete intracellular H2O2, and produce large amounts CO for a highly efficient treatment of osteoarthritis.

Specifically inhibiting the proliferation of activated macrophages and clearing the high levels of reactive oxygen species (ROS) secreted by macrophages is crucial for osteoarthritis (OA) treatment. Moreover, if the clearance of these high levels of ROS can be simultaneously used to induce oxidation-responsive release of anti-inflammatory drugs, the therapeutic effect of OA may be further improved. Here, a multifunctional anti-inflammatory drug (CPHs) based on a peptide dendrimer nanogel was constructed by physically encapsulating CORM-401 and wrapping its surface with folic acid (FA)-modified hyaluronic acid (HA). CPHs is capable of efficiently entering activated macrophages via FA- and HA-mediated specific targeting effects and then rapidly release large amounts of CO by massive consumption of H2O2. The generated CO effectively suppresses the secretion of interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α by inhibiting cell proliferation; inducing the activation of heme oxygenase (HO-1), and downregulating the expression of p38 MAPK, NF-kB (p50/p65) and TLR-2. In vivo experiments further confirmed that CPHs can massively deplete ROS in OA joints and effectively suppress the degradation of articular cartilage and their extracellular matrix. More importantly, CPHs is non-toxic to normal macrophages, and the high levels of CO generated in the joints do not result in notable changes in the HbCO levels in blood. Together, these results show that CPHs is an effective and safe anti-inflammatory drug and has essential application prospects in OA treatment.

Ultra-efficient Antibacterial System Based on Photodynamic Therapy and CO Gas Therapy for Synergistic Antibacterial and Ablation Biofilms.

In recent years, with the emergence of various kinds of drug-resistant bacteria, existing antibiotics have become inefficient in killing these bacteria, and the formation of biofilms has further weakened the therapeutic effect. More problematically, the massive use and abuse of antibiotics have caused severe side effects. Thus, the development of ultra-efficient and safe antibacterial systems is urgently needed. Herein, a photodynamic therapy (PDT)-driven CO-controlled delivery system (Ce6&CO@FADP) is developed for synergistic antibacterial and ablation biofilms. Ce6&CO@FADP is constructed using a fluorinated amphiphilic dendritic peptide (FADP) and physically loaded with Ce6 and CORM-401. After efficiently entering the bacteria, Ce6&CO@FADP can rapidly release CO intracellularly by the massive consumption of the H2O2 generated during the PDT process, without affecting the generation of singlet oxygen (1O2). As such, the combination of CO and 1O2 exerts notable synergistic antibacterial and biofilm ablation effects both in vitro and in vivo (including subcutaneous bacterial infection and biofilm catheter models) experiments. More importantly, all biosafety assessments suggest the good biocompatibility of Ce6&CO@FADP. Together, these results reveal that Ce6&CO@FADP is an efficient and safe antibacterial system, which has essential application prospects for the treatment of bacterial infections and ablation of biofilms in vivo.

Overexpression of CHKA contributes to tumor progression and metastasis and predicts poor prognosis in colorectal carcinoma.

Aberrant expression of choline kinase alpha (CHKA) has been reported in a variety of human malignancies including colorectal carcinoma (CRC). However, the role of CHKA in the progression and prognosis of CRC remains unknown. In this study, we found that CHKA was frequently upregulated in CRC clinical samples and CRC-derived cell lines and was significantly correlated with lymph node metastasis (p = 0.028), TNM stage (p = 0.009), disease recurrence (p = 0.004) and death (p < 0.001). Survival analyses indicated that patients with higher CHKA expression had a significantly shorter disease-free survival (DFS) and disease-specific survival (DSS) than those with lower CHKA expression. Multivariate analyses confirmed that increased CHKA expression was an independent unfavorable prognostic factor for CRC patients. In addition, combination of CHKA with TNM stage was a more powerful predictor of poor prognosis than either parameter alone. Functional study demonstrated that knockdown of CHKA expression profoundly suppressed the growth and metastasis of CRC cells both in vitro and in vivo. Mechanistic investigation revealed that EGFR/PI3K/AKT pathway was essential for mediating CHKA function. In conclusion, our results provide the first evidence that CHKA contributes to tumor progression and metastasis and may serve as a novel prognostic biomarker and potential therapeutic target in CRC.

Gankyrin has an antioxidative role through the feedback regulation of Nrf2 in hepatocellular carcinoma.

Oxidative stress status has a key role in hepatocellular carcinoma (HCC) development and progression. Normally, reactive oxygen species (ROS) levels are tightly controlled by an inducible antioxidant program that responds to cellular stressors. How HCC cells respond to excessive oxidative stress remains elusive. Here, we identified a feedback loop between gankyrin, an oncoprotein overexpressed in human HCC, and Nrf2 maintaining the homeostasis in HCC cells. Mechanistically, gankyrin was found to interact with the Kelch domain of Keap1 and effectively competed with Nrf2 for Keap1 binding. Increased expression of gankyrin in HCC cells blocked the binding between Nrf2 and Keap1, inhibiting the degradation of Nrf2 by proteasome. Interestingly, accumulation and translocation of Nrf2 increased the transcription of gankyrin through binding to the ARE elements in the promoter of gankyrin. The positive feedback regulation involving gankyrin and Nrf2 modulates a series of antioxidant enzymes, thereby lowering intracellular ROS and conferring a steadier intracellular environment, which prevents mitochondrial damage and cell death induced by excessive oxidative stress. Our results indicate that gankyrin is a regulator of cellular redox homeostasis and provide a link between oxidative stress and the development of HCC.

Downregulation of DHRS9 expression in colorectal cancer tissues and its prognostic significance.

Dehydrogenase/reductase (SDR family) member 9 (DHRS9) is aberrantly expressed in colorectal cancer (CRC), but its prognostic value is unknown. The aim of the work was to investigate the prognostic significance of DHRS9 expression in CRC. We found that DHRS9 was frequently downregulated in CRC clinical samples at both the messenger RNA (mRNA) and protein levels. Decreased expression of DHRS9 was significantly correlated with increased lymph node metastasis (p = 0.032), advanced tumor-node-metastasis (TNM) stage (p = 0.021), increased disease recurrence (p = 0.001), and death (p = 0.014). Kaplan-Meier analysis indicated that low DHRS9 expression predicted poor disease-free survival (p = 0.003) and disease-specific survival (p = 0.021). Cox multivariate analysis revealed that reduced expression of DHRS9 was an independent unfavorable prognostic indicator for CRC. Furthermore, combination of DHRS9 with TNM stage was a more powerful predictor of poor prognosis than either of the two parameters alone. Our results suggest that decreased expression of DHRS9 correlates with tumor progression and may serve as a potential prognostic biomarker in CRC.

Upregulation of NETO2 expression correlates with tumor progression and poor prognosis in colorectal carcinoma.

BACKGROUND: Neuropilin and tolloid-like 2 (NETO2) has been found to be overexpressed in different human cancers, but its expression pattern and clinical relevance in colorectal carcinoma (CRC) remains unknown. METHODS: Real-time quantitative PCR, western blot and immunohistochemistry analyses were used to analyze the expression of NETO2 in CRC clinical samples. The correlation of NETO2 expression with clinicopathologic features was estimated in a cohort containing 292 patients with primary CRC. Kaplan-Meier and Cox proportional hazards regression analyses were used to assess the prognostic value of NETO2 expression in CRC. RESULTS: The expression of NETO2 was frequently upregulated in CRC clinical samples at both the mRNA and protein levels, and its upregulation was significantly correlated with poor tumor differentiation (p = 0.013), advanced local invasion (p = 0.049), increased lymph node metastasis (p = 0.009), advanced TNM stage (p = 0.041) and increased patient death (p = 0.001). Kaplan-Meier analysis of the complete study cohort revealed that patients with high-NETO2 tumors had a significantly shorter disease-specific survival (DSS) than those with low-NETO2 tumors (p < 0.001). Importantly, high levels of NETO2 protein predicted poor DSS for patients with early stage tumors (p = 0.027) and for those with advanced stage tumors (p = 0.020). Furthermore, multivariate analyses indicated that increased NETO2 expression was an independent unfavorable prognostic factor for patients with early stage tumors (hazard ratio [HR] = 1.937, 95% CI = 1.107-3.390, p = 0.021) as well as patients with advanced stage tumors (HR = 2.241, 95% CI = 1.245-4.035, p = 0.007). CONCLUSIONS: Our findings suggest that NETO2 upregulation could serve as a potential biomarker for the prediction of advanced tumor progression and unfavorable prognosis in patients with CRC.

FAT4 functions as a tumour suppressor in gastric cancer by modulating Wnt/ß-catenin signalling.

BACKGROUND: FAT4, a cadherin-related protein, was shown to function as a tumour suppressor; however, its role in human gastric cancer remains largely unknown. Here, we investigated the role of FAT4 in gastric cancer and examined the underlying molecular mechanisms. METHODS: The expression of FAT4 was evaluated by immunohistochemistry, western blotting, and qRT-PCR in relation to the clinicopathological characteristics of gastric cancer patients. The effects of FAT4 silencing on cell proliferation, migration, and invasion were assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) assay, and migration and invasion assays in gastric cancer cell lines in vitro and in a mouse xenograft model in vivo. RESULTS: Downregulation of FAT4 expression in gastric cancer tissues compared with adjacent normal tissues was correlated with lymph-node metastasis and poor survival. Knockdown of FAT4 promoted the growth and invasion of gastric cancer cells via the activation of Wnt/ß-catenin signalling, and induced epithelial-to-mesenchymal transition (EMT) in gastric cancer cells, as demonstrated by the upregulation and downregulation of mesenchymal and epithelial markers. Silencing of FAT4 promoted tumour growth and metastasis in a gastric cancer xenograft model in vivo. CONCLUSIONS: FAT4 has a tumour suppressor role mediated by the modulation of Wnt/ß-catenin signalling, providing potential novel targets for the treatment of gastric cancer.

Overexpression of SULT2B1b is an independent prognostic indicator and promotes cell growth and invasion in colorectal carcinoma.

Aberrant expression of cytosolic sulfotransferase 2B1b (SULT2B1b) has been reported in several human malignancies. However, the expression pattern and clinical significance of SULT2B1b in colorectal carcinoma (CRC) remains unknown. Real-time quantitative PCR, western blot, and immunohistochemistry analyses were used to determine SULT2B1b expression in CRC clinical samples and CRC-derived cell lines. Kaplan-Meier and Cox proportional regression analyses were used to evaluate the association between SULT2B1b expression and patient survival in two independent cohorts of 485 patients with CRC. Gain- and loss-of-function approaches were employed to investigate the role of SULT2B1b in regulation of CRC cell growth and invasion. We found that SULT2B1b expression was frequently upregulated in CRC clinical samples and CRC-derived cell lines and was significantly correlated with lymph node metastasis and TNM stage in both the training and validation cohorts. Patients with higher intratumoral SULT2B1b expression had a significantly shorter disease-specific survival (DSS) and disease-free survival (DFS) than those with lower expression. Importantly, increased expression of SULT2B1b significantly predicted poor DSS and DFS and was an independent unfavorable prognostic indicator for stage II patients in both cohorts. Functional studies revealed that overexpression of SULT2B1b promoted CRC cell growth and invasion in vitro. Conversely, knockdown of SULT2B1b inhibited these processes. In conclusion, our findings suggest that SULT2B1b expression correlates with disease progression and metastasis and may serve as a novel prognostic biomarker and potential therapeutic target for patients with CRC.

Serine threonine tyrosine kinase 1 is a potential prognostic marker in colorectal cancer.

BACKGROUND: Aberrant expression of serine threonine tyrosine kinase 1 (STYK1) has been reported in several human malignancies including colorectal cancer (CRC). However, the prognostic significance of STYK1 expression in CRC remains unknown. METHODS: STYK1 protein expression in paraffin-embedded CRC specimens was determined immunohistochemically. The correlation of STYK1 expression with clinicopathologic features was assessed in a cohort containing 353 patients with primary CRC. Kaplan-Meier and Cox proportional regression analyses were used to evaluate the association between STYK1 expression and patients' survival. RESULTS: STYK1 expression was frequently up-regulated in CRC clinical samples at the protein levels and was significantly associated with tumor differentiation grade (p = 0.030), lymph node metastasis (p = 0.004), TNM stage (p = 0.007) and patient death (p < 0.001). Kaplan-Meier analysis indicated that patients with high intratumoral STYK1 expression had a significantly shorter disease-specific survival (DSS) than those with low expression (p < 0.001). Importantly, high levels of STYK1 protein predicted poor DSS for both stage II (p < 0.001) and stage III (p = 0.004) patients. Furthermore, multivariate analyses revealed that STYK1 protein expression was an independent prognostic indicator for both stage II (hazard ratio [HR], 2.472; p = 0.001) and stage III (HR, 2.001; p = 0.004) patients. CONCLUSIONS: Our results suggest that increased STYK1 protein expression correlates with disease progression and metastasis and may serve as a predictor of poor survival in CRC.

Prognostic value of carbonic anhydrase VII expression in colorectal carcinoma.

BACKGROUND: Carbonic anhydrases (CAs) have been implicated in the pathogenesis of human cancers. Carbonic anhydrase VII (CA7), a member of the CA gene family, was recently demonstrated to be expressed in several human tissues including colon. Nevertheless, the expression and clinical relevance of CA7 in colorectal carcinoma (CRC) has not been investigated. METHODS: Real-time PCR, western blot, and immunohistochemistry analyses were used to determine CA7 expression in CRC clinical samples. The correlation of CA7 expression with clinicopathologic features was assessed in 228 patients from Luoyang, China (training cohort) and validated in 151 patients from Shanghai, China (validation cohort). Kaplan-Meier and Cox proportional regression analyses were used to estimate the association between CA7 expression and patients' survival. RESULTS: CA7 expression was frequently downregulated in CRC tissues at both the mRNA and protein levels. Reduced expression of CA7 was significantly correlated with poor differentiation, positive lymph node metastasis, advanced TNM stage and unfavorable clinical outcome not only in the training cohort but also in the validation set. Survival analysis indicated that patients with lower CA7 expression had a significantly shorter disease-specific survival (DSS) than those with higher CA7 expression. Importantly, further stage-based analyses revealed that decreased CA7 expression significantly predicted poor DSS and was an independent adverse prognostic indicator for patients with early stage tumors in both cohorts. CONCLUSIONS: Our results indicate that decreased expression of CA7 correlates with disease progression and predicts poor prognosis in CRC, especially for patients with early stage tumors.

RMP predicts survival and adjuvant TACE response in hepatocellular carcinoma.

Adjuvant transcatheter arterial chemoembolization (TACE) protects against hepatocellular carcinoma (HCC) and is associated with reduced disease recurrence and improved outcome after surgery. However, deterioration of liver function after TACE negatively impacts the patient prognosis and limits it use as an option to prolong survival. We analyzed two independent cohorts that included a total of 510 patients with HCC who had undergone tumor resection. Immunohistochemistry assay was used to measure RPB5-mediating protein (RMP) expression and assessed their association with recurrence rate and response to therapy with adjuvant TACE. In patients with HCC, the expression of RMP in tumor is associated with age, gender, tumor size, portal venous invasion, TNM stages, BCLC stages and overall survival. Among patients with high RMP expression, adjuvant TACE after resection was associated with early recurrence. Even in the patients with small tumor size (no more than 5 cm) or no venous invasion, RMP status is associated with response to adjuvant TACE. RMP status in tumors may be a useful marker in estimating prognosis in patients with HCC and in assisting in the selection of patients who are likely to benefit from adjuvant TACE to prevent relapse.

The prognostic significance and therapeutic potential of hedgehog signaling in intrahepatic cholangiocellular carcinoma.

PURPOSE: The correlation of the hedgehog signaling pathway with the progression, prognosis, and therapeutics of intrahepatic cholangiocellular carcinoma (ICC) has not been well documented. The study aimed to investigate the expression, prognostic significance, and therapeutic value of hedgehog components in ICC. EXPERIMENTAL DESIGN: Two independent cohorts of 200 patients with ICC were enrolled. By real-time PCR and immunohistochemistry assay, hedgehog components expression was evaluated. The prognostic values of hedgehog proteins were identified and verified. Cyclopamine or siRNA-targeting Gli was used to block the hedgehog signaling. Cell proliferation and apoptosis were observed by CCK8, cell cycle, and annexin V staining assays. In vivo murine tumor model was used to evaluate the role of hedgehog in ICC. RESULTS: In ICC tissues, the Gli1 nuclear immune-intensity was associated with intrahepatic metastasis and the expression of Gli2 was associated with intrahepatic metastasis, venous invasion, and Unio Internationale Contra Cancrum (UICC) pT characteristics. In survival analysis, high Gli1 or Gli2 expressers had an unfavorable overall survival (OS) prognosis and a shorter disease-free survival (DFS) than those with low expression. In multivariate analysis, Gli1 expression was found to be an independent prognostic factor of OS, which was validated by another independent cohort. Furthermore, blocking the hedgehog signaling by cyclopamine or siRNA-targeting Gli1 resulted in apoptosis and growth inhibition in ICC cells. CONCLUSIONS: This study shows, for the first time, activation of hedgehog pathway associated with the progression and metastasis in ICC, which may provide prognostic and therapeutic values for this tumor.

Signal regulatory protein α negatively regulates mast-cell activation following FcεRI aggregation.

Mast cells elicit allergic reaction through degranulation and release of proinflammatory mediators after aggregation of the IgE receptor FcεRI. Here we provide evidence to show that signal regulatory protein α (SIRPα), an ITIM-containing receptor, is an endogenous regulator of IgE-Ag induced mast-cell activation. SIRPα expression is promptly reduced in mast cells in response to FcεRI aggregation. Impaired expression of SIRPα in mast cells facilitates FcεRI-evoked degranulation and de novo synthesis of cytokines (IL-4, IL-13, IL-6, and TNF-α). We further demonstrate that SIRPα knockdown in mast cells accelerates calcium mobilization and affects cytoskeletal rearrangement (F-actin disassembly and polymeric tubulin formation) after FcεRI aggregation. Mechanistic studies highlight the prolonged activation of NF-κB and MAPKs as well as PLC-γ after FcεRI stimulation as a consequence of the inhibition of SIRPα expression in mast cells. Immunoprecipitation analysis shows that SIRPα knockdown markedly increases IgE-induced SHP2 interaction with PI3K regulatory subunit PI3Kp85 or IKK-ß in mast cells, indicating that SIRPα may accomplish this through its association and sequestration of SHP2. Collectively, our results strongly indicate that SIRPα is a biological important regulator of FcεRI signaling.

Inhibition of active autophagy induces apoptosis and increases chemosensitivity in cholangiocarcinoma.

Intrahepatic cholangiocellular carcinomas (ICCs) are usually fatal neoplasms originating from bile duct epithelia. However, many cholangiocarcinoma cells are shown to be resistant to chemotherapeutic drugs, which induce cell apoptosis. The role of autophagy and the therapeutic value of autophagy-associated genes are largely unknown in ICC. Here, we showed that autophagy was activated in nutrient starvation and xenograft cholangiocarcinoma cells. Furthermore, expression of autophagic genes and their autophagic activity were higher in clinical ICC specimens than that in normal cholangiocytes separated by laser capture microdissection. Inhibition of autophagy by autophagy inhibitors or siRNA, cholangiocarcinoma cells showed detention of proliferation and increase of apoptosis during nutrient starvation. In addition, autophagy inhibitor treatment or knockdown of beclin 1 suppressed tumor growth and sensitized ICC cells to chemotherapeutic agent-induced cell death. In conclusion, our data showed that autophagy is activated in ICC, and inactivation of autophagy may lead to cell apoptosis and enhance chemotherapy sensitivity.

The oncoprotein p28GANK establishes a positive feedback loop in ß-catenin signaling.

p28(GANK) (also known as PSMD10 or gankyrin) is a novel oncoprotein that is highly expressed in hepatocellular carcinoma (HCC). Through its interaction with various proteins, p28(GANK) mediates the degradation of the tumor suppressor proteins Rb and p53. Although p53 was reported to downregulate ß-catenin, whether p28(GANK) is involved in the regulation of ß-catenin remains uncertain. Here we report that both growth factors and Ras upregulate p28(GANK) expression through the activation of the phosphoinositide 3-kinase-AKT pathway. Upregulation of p28(GANK) expression subsequently enhanced the transcription activity of ß-catenin. This effect was observed in p53-deficient cells, suggesting a p53-independent mechanism for the p28(GANK)-mediated activation of ß-catenin. p28(GANK) overexpression also reduced E-cadherin protein levels, leading to increased release of free ß-catenin into the cytoplasm from the cadherin-bound pool. Interestingly, exogenous expression of p28(GANK) resulted in elevated expression of the endogenous protein. We also observed that both ß-catenin and c-Myc were transcriptional activators of p28(GANK), and a correlation between p28(GANK) overexpression and c-Myc, cyclin D1 and ß-catenin activation in primary human HCC. Together, these results suggest that p28(GANK) expression is regulated by a positive feedback loop involving ß-catenin, which may play a critical role in tumorigenesis and the progression of HCC.

HBx sensitizes cells to oxidative stress-induced apoptosis by accelerating the loss of Mcl-1 protein via caspase-3 cascade.

BACKGROUND: Oxidative stress has been implicated in the pathogenesis of a wide spectrum of human diseases, including Hepatitis B virus (HBV)-related liver disease. Hepatitis B virus X protein (HBx) is a key regulator of HBV that exerts pleiotropic activity on cellular functions. Recent studies showed that HBx alters mitochondrial membrane potential, thereby sensitizing cells to pro-apoptotic signals. However, it remains largely unknown whether susceptibility of hepatocytes could be disturbed by HBx under oxidative stress conditions. The purpose of this study is to determine the apoptotic susceptibility of HBx-expressing hepatocytes upon exposure to pro-oxidant stimuli in vitro and in vivo and explore its underlying mechanism. RESULTS: Although expression of HBx itself did not activate apoptotic signaling, it significantly enhanced oxidative stress-induced cell death both in vitro and in vivo. Interestingly, this phenomenon was associated with a pronounced reduction of protein levels of Mcl-1, but not other anti-apoptotic Bcl-2 members. Importantly, enforced expression of Mcl-1 prevented HBx-triggered cell apoptosis; conversely, specific knockdown of Mcl-1 exacerbated HBx-induced apoptosis upon exposure to oxidative stress. Furthermore, inhibition of caspase-3 not only abrogated HBx-triggered apoptotic killing but also blocked HBx-induced Mcl-1 loss. Additionally, expression of HBx and Mcl-1 was found to be inversely correlated in HBV-related hepatocellular carcinogenesis (HCC) tissues. CONCLUSIONS: Our findings indicate that HBx exerts pro-apoptotic effect upon exposure to oxidative stress probably through accelerating the loss of Mcl-1 protein via caspase-3 cascade, which may shed a new light on the molecular mechanism of HBV-related hepatocarcinogenesis.

Hepatitis B virus X protein enhances cisplatin-induced hepatotoxicity via a mechanism involving degradation of Mcl-1.

Hepatitis B virus X protein (HBx) is implicated in the pathogenesis of hepatitis B virus (HBV)-associated liver diseases. However, whether HBx has the ability to disturb the susceptibility of hepatocytes to common chemotherapeutic agents remains incompletely understood. Here we demonstrate that HBx enhances cisplatin-induced hepatotoxicity by a mechanism involving degradation of Mcl-1, an antiapoptotic member of the Bcl-2 family. Ectopic expression of HBx sensitized hepatocytes to cisplatin-induced apoptosis, which was accompanied by a marked downregulation of Mcl-1 but not of Bcl-2 or Bcl-xL. Overexpression of Mcl-1 prevented HBx-induced proapoptotic and proinflammatory effects during cisplatin treatment both in vitro and in vivo. HBx-induced dysregulation of Mcl-1 resulted mainly from posttranslational degradation rather than transcription repression. Moreover, a caspase-3 inhibitor effectively abrogated HBx-enhanced Mcl-1 degradation and cell death. Importantly, antioxidants blocked activation of caspase-3 and acceleration of Mcl-1 loss, as well as cell death, in HBx-expressing hepatocytes upon cisplatin exposure in vitro and in vivo. Collectively, these data implicate oxidative stress-dependent caspase-3-mediated degradation of Mcl-1 as a mechanism contributing to HBx-mediated sensitization of cisplatin-induced hepatotoxicity. A combination of cisplatin and antioxidants might provide more advantage than cisplatin alone in the treatment of cancer patients with chronic HBV infection.

p28GANK inhibits endoplasmic reticulum stress-induced cell death via enhancement of the endoplasmic reticulum adaptive capacity.

It has been shown that oncoprotein p28(GANK), which is consistently overexpressed in human hepatocellular carcinoma (HCC), plays a critical role in tumorigenesis of HCC. However, the underlying mechanism remains unclear. Here, we demonstrated that p28(GANK) inhibits apoptosis in HCC cells induced by the endoplasmic reticulum (ER) stress. During ER stress, p28(GANK) enhances the unfolded protein response, promotes ER recovery from translational repression, and thereby facilitates cell's ability to cope with the stress conditions. Furthermore, p28(GANK) upregulates glucose-regulated protein 78 (GRP78), a key ER chaperone protein, which subsequently enhances the ER folding capacity and promotes recovery from ER stress. We also demonstrated that p28(GANK) increases p38 mitogen-activated protein kinase and Akt phosphorylation, and inhibits nuclear factor kappa B (NF-kappaB) activation under ER stress, which in turn contributes to GRP78 upregulation. Taken together, our results indicate that p28(GANK) inhibits ER stress-induced apoptosis in HCC cells, at least in part, by enhancing the adaptive response and GRP78 expression. We propose that p28(GANK) has potential implications for HCC progression under the ER stress conditions.

Expression of the APLA(2) Gene from Agkistrodon halys Pallas.

The APLA(2) gene from Agkistrodon halys Pallas has been cloned into the expression plasmid pBLMVL2 and expressed in E. coli RR1. The molecular weight of the expressed product is approximately 14 kD as shown by SDS-PAGE, its expression level is about 30% of the total cellular proteins. The protein was produced as insoluble inclusion bodies. After partially purified by washing the inclusion bodies, the product was denatured and refolded into active form. Then, the expressed APLA(2) was purified by FPLC Superose (TM) 12 and was a single band as shown by SDS-PAGE. The purified expressed protein had specific activity as the native enzyme and cross-reacted with antisera prepared against the native enzyme. The successful expression of the APLA(2) gene from Agkistrodon halys Pallas provides a good basis for further structure-function studies.