Rational design, synthesis and structural characterization of peptides and peptidomimetics to target Hsp90/Cdc37 interaction for treating hepatocellular carcinoma.

Heat shock protein 90 (Hsp90) and cell division cycle 37 (Cdc37) work together as a molecular chaperone complex to regulate the activity of a multitude of client protein kinases. These kinases belong to a wide array of intracellular signaling networks that mediate multiple cellular processes including proliferation. As a result, Hsp90 and Cdc37 represent innovative therapeutic targets in various cancers (such as leukemia, multiple myeloma, and hepatocellular carcinoma (HCC)) in which their expression levels are elevated. Conventional small molecule Hsp90 inhibitors act by blocking the conserved adenosine triphosphate (ATP) binding site. However, by targeting less conserved sites in a more specific manner, peptides and peptidomimetics (modified peptides) hold potential as more efficacious and less toxic alternatives to the conventional small molecule inhibitors. Using a rational approach, we herein developed bioactive peptides targeting Hsp90/Cdc37 interaction. A six amino acid linear peptide derived from Cdc37, KTGDEK, was designed to target Hsp90. We used in silico computational docking to first define its mode of interaction, and binding orientation, and then conjugated the peptide with a cell penetrating peptide, TAT, and a fluorescent dye to confirm its ability to colocalize with Hsp90 in HCC cells. Based on the parent linear sequence, we developed a peptidomimetics library of pre-cyclic and cyclic derivatives. These peptidomimetics were evaluated for their binding affinity to Hsp90, and bioactivity in HCC cell lines. Among them, a pre-cyclic peptidomimetic demonstrates high binding affinity and bioactivity in HCC cells, causing reduced cell proliferation that is associated with induction of cell apoptosis, and down-regulation of phosphorylated MEK1/2. Overall, this generalized approach of rational design, structural optimization, and cellular validation of 'drug-like' peptidomimetics against Hsp90/Cdc37 offers a feasible and promising way to design novel therapeutic agents for malignancies and other diseases that are dependent on this molecular chaperone complex.

Exploring Biomolecular Interaction Between the Molecular Chaperone Hsp90 and Its Client Protein Kinase Cdc37 using Field-Effect Biosensing Technology.

Biomolecular interactions play versatile roles in numerous cellular processes by regulating and coordinating functionally relevant biological events. Biomolecules such as proteins, carbohydrates, vitamins, fatty acids, nucleic acids, and enzymes are fundamental building blocks of living beings; they assemble into complex networks in biosystems to synchronize a myriad of life events. Proteins typically utilize complex interactome networks to carry out their functions; hence it is mandatory to evaluate such interactions to unravel their importance in cells at both cellular and organism levels. Toward this goal, we introduce a rapidly emerging technology, field-effect biosensing (FEB), to determine specific biomolecular interactions. FEB is a benchtop, label-free, and reliable biomolecular detection technique to determine specific interactions and uses high-quality electronic-based biosensors. The FEB technology can monitor interactions in the nanomolar range due to the biocompatible nanomaterials used on its biosensor surface. As a proof of concept, the protein-protein interaction (PPI) between heat shock protein 90 (Hsp90) and cell division cycle 37 (Cdc37) was elucidated. Hsp90 is an ATP-dependent molecular chaperone that plays an essential role in the folding, stability, maturation, and quality control of many proteins, thereby regulating multiple vital cellular functions. Cdc37 is regarded as a protein kinase-specific molecular chaperone, as it specifically recognizes and recruits protein kinases to Hsp90 to regulate their downstream signal transduction pathways. As such, Cdc37 is considered a co-chaperone of Hsp90. The chaperone-kinase pathway (Hsp90/Cdc37 complex) is hyper-activated in multiple malignancies promoting cellular growth; therefore, it is a potential target for cancer therapy. The present study demonstrates the efficiency of FEB technology using the Hsp90/Cdc37 model system. FEB detected a strong PPI between the two proteins (KD values of 0.014 µM, 0.053 µM, and 0.072 µM in three independent experiments). In summary, FEB is a label-free and cost-effective PPI detection platform, which offers fast and accurate measurements.

A Humanized Anti-GPC3 Antibody for Immuno-Positron Emission Tomography Imaging of Orthotopic Mouse Model of Patient-Derived Hepatocellular Carcinoma Xenografts.

Glypican-3 (GPC3) is an attractive diagnostic marker for hepatocellular carcinoma (HCC). We previously reported the potential of an 89Zr-labeled murine anti-GPC3 antibody (clone 1G12) for immunoPET imaging of HCC in orthotopic patient-derived xenograft (PDX) mouse models. We now humanized the murine antibody by complementarity determining region (CDR) grafting, to allow its clinical translation for human use. The engineered humanized anti-GPC3 antibody, clone H3K3, retained comparable binding affinity and specificity to human GPC3. H3K3 was conjugated with desferrioxamine (Df) and radiolabeled with 89Zr to produce the PET/CT tracer 89Zr-Df-H3K3. When injected into GPC3-expressing orthotopic HCC PDX in NOD SCID Gamma (NSG) mice, 89Zr-Df-H3K3 showed specific high uptake into the orthotopic PDX and minimal, non-specific uptake into the non-tumor bearing liver. Specificity was demonstrated by significantly higher uptake of 89Zr-Df-H3K3 into the non-blocked PDX mice, compared with the blocked PDX mice (which received prior injection of 100 mg of unlabeled H3K3). Region of interest (ROI) analysis showed that the PDX/non-tumor liver ratio was highest (mean ± SD: 3.4 ± 0.31) at 168 h post injection; this ratio was consistent with biodistribution studies at the same time point. Thus, our humanized anti-GPC3 antibody, H3K3, shows encouraging potential for use as an immunoPET tracer for diagnostic imaging of HCC patients.

An NIR-II/MR dual modal nanoprobe for liver cancer imaging.

Hepatocellular carcinoma (HCC) is a malignancy of the liver worldwide and surgical resection remains the most effective treatment. However, it is still a great challenge to locate small lesions and define the border of diffused HCC even with the help of preoperative imaging examination. Here, we reported a rare-earth-doped nanoparticle NaGdF4:Nd 5%@NaGdF4@Lips (named Gd-REs@Lips), which simultaneously performed powerful functions in both magnetic resonance imaging (MRI) and second near-infrared fluorescence window imaging (NIR-II, 1000-1700 nm). Imaging studies on orthotopic models with xenografts established from HCC patients indicated that Gd-REs@Lips efficiently worked as a T2-weighted imaging contrast agent to increase the signal intensity difference between liver cancer tissues and surrounding normal liver tissues on MRI, and it can also serve as a negative NIR-II imaging contrast enabling the precise detection of liver cancer. More importantly, benefiting from the high sensitivity of NIR-II imaging, Gd-REs@Lips allowed the visualization of tiny metastasis lesions (2 mm) on the liver surface. It is expected that the dual NIR-II/MRI modal nanoprobe developed holds high potential to fill the gap between the preoperative imaging detection of cancer lesions and intra-operative guidance, and it further brings new opportunities to address HCC-related medical challenges.

Management of hepatitis B infected pregnant women: a cross-sectional study of obstetricians.

BACKGROUND: Our study aims to describe how obstetricians manage pregnant women infected with chronic hepatitis B in a region with a large high-risk population. METHODS: We performed a cross-sectional study among practicing obstetricians in Santa Clara County, California. All obstetricians practicing in Santa Clara County were invited to participate in the study. Obstetricians were recruited in person or by mail to complete a voluntary, multiple choice survey on hepatitis B (HBV). Survey questions assessed basic HBV knowledge and obstetricians' self-reported clinical practices of the management of HBV-infected pregnant women. Pooled descriptive analyses were calculated for the cohort, as well as, correlation coefficients to evaluate the association between reported clinical practices and hepatitis B knowledge. RESULTS: Among 138 obstetricians who completed the survey, 94% reported routinely testing pregnant women for hepatitis B surface antigen (HBsAg) with each pregnancy. Only 60.9% routinely advised HBsAg-positive patients to seek specialist evaluation for antiviral treatment and monitoring and fewer than half (48.6%) routinely provided them with HBV information. While most respondents recognized the potential complications of chronic HBV (94.2%), only 21% were aware that chronic HBV carries a 25% risk of liver related death when left unmonitored and untreated, and only 25% were aware of the high prevalence of chronic HBV in the foreign-born Asian, Native Hawaiian and Pacific Islander population. Obstetricians aware of the high risk of perinatal HBV transmission were more likely to test pregnant women for HBV DNA or hepatitis B e-antigen in HBV-infected women (r = 0.18, p = 0.033). Obstetricians who demonstrated knowledge of the long-term consequences of untreated HBV infection were no more likely to refer HBV-infected women to specialists for care (r = 0.02, p = 0.831). CONCLUSION: Our study identified clear gaps in the practice patterns of obstetricians that can be readily addressed to enhance the care they provide to HBV-infected pregnant women.

Racial/ethnic- and county-specific prevalence of chronic hepatitis B and its burden in California.

BACKGROUND: In the United States, the highest burden of chronic hepatitis B (CHB) and CHB-related liver cancer is in the state of California, primarily in the San Francisco (SF) Bay and Los Angeles (LA) areas. The aim of this study was to estimate county-specific hepatitis B surface antigen (HBsAg) prevalence and quantify CHB cases by age, race/ethnicity, nativity, and disease activity status. METHODS: Twelve counties in SF Bay Area and three large counties in LA area were included for this analysis. Race/ethnicity-specific prevalence of HBsAg for each county and the state of California as a whole, was estimated by including prevalence data from the National Health and Nutrition Examination Survey and various studies that estimated HBsAg prevalence in US and foreign-born Asian Pacific Islanders, Hispanic, and Black populations. In addition, clinical data of 2000 consecutive CHB patients (collected between 2009 and 2014) from a large clinical consortium in the SF Bay area were used to calculate the age-specific disease burden. RESULTS: Of the 15 counties analyzed, SF had the highest HBsAg prevalence (1.78%), followed by Santa Clara (1.63%) and Alameda (1.45%). The majority of CHB cases were estimated to be in LA County (83,770), followed by Santa Clara (31,273), and Alameda (23,764). Among the CHB cases, 12.7% is active HBeAg positive, 24.2% is active HBeAg negative, and 10.6% has cirrhosis. CONCLUSION: This study confirms and quantifies the current burden of CHB in high endemic counties in the state of California using population-level estimates combined with clinical data including those from the community.

Disparities in hepatocellular carcinoma incidence by race/ethnicity and geographic area in California: Implications for prevention.

BACKGROUND: The incidence of hepatocellular carcinoma (HCC) has been rising rapidly in the United States. California is an ethnically diverse state with the largest number of incident HCC cases in the country. Characterizing HCC disparities in California may inform priorities for HCC prevention. METHODS: By using data from the Surveillance, Epidemiology, and End Results 18-Registry Database and the California Cancer Registry, age-adjusted HCC incidence in California from 2009 through 2013 was calculated by race/ethnicity and neighborhood ethnic enclave status. A geographic analysis was conducted using Medical Service Study Areas (MSSAs) as the geographic unit, and race/ethnicity-specific standardized incidence ratios (SIRs) were calculated to identify MSSAs with higher-than-expected HCC incidence compared with the statewide average. RESULTS: During 2009 through 2013, the age-adjusted incidence of HCC in California was the highest in Asians/Pacific Islanders (APIs) and Hispanics (>100% higher than whites), especially those living in more ethnic neighborhoods (20%-30% higher than less ethnic neighborhoods). Of the 542 MSSAs statewide, 42 had elevated HCC incidence (SIR ≥ 1.5; lower bound of 95% confidence interval > 1) for whites, 14 for blacks, 24 for APIs, and 36 for Hispanics. These MSSAs have 24% to 52% higher proportions of individuals below the 100% federal poverty line than other MSSAs. CONCLUSIONS: APIs and Hispanics residing in more ethnic neighborhoods and individuals residing in lower income neighborhoods require more extensive preventive efforts tailored toward their unique risk factor profiles. The current race/ethnicity-specific geographic analysis can be extended to other states to inform priorities for HCC targeted prevention at the subcounty level, eventually reducing HCC burden in the country.

Cost-Effectiveness and Cost Thresholds of Generic and Brand Drugs in a National Chronic Hepatitis B Treatment Program in China.

Chronic liver disease and liver cancer associated with chronic hepatitis B (CHB) are leading causes of death among adults in China. Although newborn hepatitis B immunization has successfully reduced the prevalence of CHB in children, about 100 million Chinese adults remain chronically infected. If left unmanaged, 15-25% will die from liver cancer or liver cirrhosis. Antiviral treatment is not necessary for all patients with CHB, but when it is indicated, good response to treatment would prevent disease progression and reduce disease mortality and morbidity, and costly complications. The aim of this study is to analyze the cost-effectiveness of generic and brand antiviral drugs for CHB treatment in China, and assessing various thresholds at which a highly potent, low resistance antiviral drug would be cost-saving and/or cost-effective to introduce in a national treatment program. We developed a Markov simulation model of disease progression using effectiveness and cost data from the medical literature. We measured life-time costs, quality adjusted life years (QALYs), incremental cost-effectiveness ratios (ICERs), and clinical outcomes. The no treatment strategy incurred the highest health care costs ($12,932-$25,293) per patient, and the worst health outcomes, compared to the antiviral treatment strategies. Monotherapy with either entecavir or tenofovir yielded the most QALYs (14.10-19.02) for both HBeAg-positive and negative patients, with or without cirrhosis. Threshold analysis showed entercavir or tenofovir treatment would be cost saving if the drug price is $32-75 (195-460 RMB) per month, highly cost-effective at $62-110 (379-670 RMB) per month and cost-effective at $63-120 (384-734 RMB) per month. This study can support policy decisions regarding the implementation of a national health program for chronic hepatitis B treatment in China at the population level.

Suppression of ATAD2 inhibits hepatocellular carcinoma progression through activation of p53- and p38-mediated apoptotic signaling.

The ATPase family, AAA domain containing 2 (ATAD2) is highly expressed in multiple cancers. We aim to understand the clinical and biological significance of ATAD2 over-expression in hepatocellular carcinoma (HCC), as a means to validate it as a therapeutic target in HCC. We demonstrated that ATAD2 was over-expressed in HCC patients, where high ATAD2 levels were significantly correlated with aggressive phenotypes such as high AFP levels, advanced tumor stages, and vascular invasion. Using RNA interference, suppression of ATAD2 in HCC cell lines decreased cell viability, migration, and invasion, and induced apoptosis in vitro. Furthermore, we identified p53 and p38 as key proteins that mediate apoptosis induced by ATAD2 suppression. In HCC cells, we demonstrated that ATAD2 directly interacted with MKK3/6, which prevented p38 activation and therefore inhibited p38-mediated apoptosis. In vivo, suppression of ATAD2 impaired the growth of HepG2 and Hep3B subcutaneous xenografts, accompanied by enhanced apoptosis and p-p53 and p-p38 levels. Our results validate that ATAD2 is an important negative regulator of apoptosis, and that neutralizing its activity has promising anti-tumor effects in HCC cells.

NDRG1 promotes growth of hepatocellular carcinoma cells by directly interacting with GSK-3ß and Nur77 to prevent ß-catenin degradation.

The N-myc downstream regulated gene 1 (NDRG1) is significantly associated with advanced tumor stages and poor survival of hepatocellular carcinoma (HCC), thereby implicating it as a potential target for HCC treatment. We aim to further understand its biological roles in hepatocarcinogenesis, as a means to exploit it for therapeutic purposes. By screening using the ProtoArray® Human Protein Microarrays, we identified glycogen synthase kinase 3ß (GSK-3ß) and the orphan nuclear receptor (Nur77) as potential interaction partners of NDRG1. These interactions were confirmed in HCC cell lines in vitro by co-immunoprecipitation; and co-localizations of NDRG1 with GSK-3ß and Nur77 were observed by immunofluorescence staining. Additionally, high levels of NDRG1 competitively bind to GSK-3ß and Nur77 to allow ß-catenin to escape degradation, with consequent elevated levels of downstream oncogenic genes. In vivo, we consistently observed that NDRG1 suppression in HCC xenografts decreased ß-catenin levels and its downstream target Cyclin D1, with concomitant tumor growth inhibition. Clinically, the over-expression of NDRG1 in HCC patient samples is positively correlated with GSK-3ß-9ser (|”‚ R | = 0.28, p = 0.01), Nur77 (|”‚ R | = 0.42, p < 0.001), and ß-catenin (| R |= 0.32, p = 0.003) expressions. In conclusion, we identified GSK-3ß and Nur77 as novel interaction partners of NDRG1. These protein-protein interactions regulate the turnover of ß-catenin and subsequent downstream signaling mediated by ß-catenin in HCC cells, and provides potential targets for future therapeutic interventions.

Medical training fails to prepare providers to care for patients with chronic hepatitis B infection.

AIM: To investigate physicians' knowledge including chronic hepatitis B (CHB) diagnosis, screening, and management in various stages of their training. METHODS: A voluntary 20-question survey was administered in Santa Clara County, CA where Asian and Pacific Islanders (API) account for a third of the population. Among the 219 physician participants, there were 63 interns, 60 second-year residents, 26 chief residents and 70 attending physicians. The survey asked questions regarding respondents' demographics, general hepatitis B virus knowledge questions (i.e., transmission, prevalence, diagnostic testing, prevention, and treatment options), as well as, self-reported practice behavior and confidence in knowledge. RESULTS: Knowledge about screening and managing patients with CHB was poor: only 24% identified the correct tests to screen for CHB, 13% knew the next steps for patients testing positive for CHB, 18% knew the high prevalence rate among API, and 31% knew how to screen for liver cancer. Wald chi-square analysis determined the effect of training level on knowledge; in all cases except for knowledge of liver cancer screening (P = 0.0032), knowledge did not significantly increase with length in residency training or completion of residency. CONCLUSION: Even in a high-risk region, both medical school and residency training have not adequately prepared physicians in the screening and management of CHB.

Imaging of hepatocellular carcinoma patient-derived xenografts using 89Zr-labeled anti-glypican-3 monoclonal antibody.

Imaging probes for early detection of hepatocellular carcinoma (HCC) are highly desired to overcome current diagnostic limitations which lead to poor prognosis. The membrane protein glypican-3 (GPC3) is a potential molecular target for early HCC detection as it is over-expressed in >50% of HCCs, and is associated with early hepatocarcinogenesis. We synthesized the positron emission tomography (PET) probe (89)Zr-DFO-1G12 by bioconjugating and radiolabeling the anti-GPC3 monoclonal antibody (clone 1G12) with (89)Zr, and evaluated its tumor-targeting capacity. In vitro, (89)Zr-DFO-1G12 was specifically taken up into GPC3-positive HCC cells only, but not in the GPC3-negative prostate cancer cell line (PC3). In vivo, (89)Zr-DFO-1G12 specifically accumulated in subcutaneous GPC3-positive HCC xenografts only, but not in PC3 xenografts. Importantly, (89)Zr-DFO-1G12 delineated orthotopic HCC xenografts from surrounding normal liver, with tumor/liver (T/L) ratios of 6.65 ± 1.33 for HepG2, and 4.29 ± 0.52 for Hep3B xenografts. It also delineated orthotopic xenografts derived from three GPC3-positive HCC patient specimens, with T/L ratios of 4.21 ± 0.64, 2.78 ± 0.26, and 2.31 ± 0.38 at 168 h p.i. Thus, (89)Zr-DFO-1G12 is a highly translatable probe for the specific and high contrast imaging of GPC3-positive HCCs, which may aid early detection of HCC to allow timely intervention.

Suppressing N-Myc downstream regulated gene 1 reactivates senescence signaling and inhibits tumor growth in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the fifth most lethal malignancy worldwide with no curative therapies. To discover potentially novel therapeutic targets for HCC, we previously studied the gene expression profiles of HCC patients and identified that significant upregulation of N-Myc downstream regulated gene 1 (NDRG1) is associated with more aggressive phenotypes and poorer overall survival of HCC patients. In this study, we further used a loss-of-function approach (RNA interference) to understand the role of NDRG1 in hepatocarcinogenesis. We found that suppression of NDRG1 significantly impaired HCC cell growth through inducing extensive cellular senescence of HCC cells both in vitro and in vivo, accompanied by cell cycle arrest at the G1 phase. The observed antitumor effects of NDRG1 suppression were correlated with activation of major senescence-associated signaling pathways, such as upregulation of tumor suppressors p53, p21 and p16, and decreased phosphorylated Rb. To obtain further insights into the clinical significance of NDRG1-modulated senescence in HCC patients, immunohistochemistry staining of 92 cases of HCC patients was done. We found that high NDRG1 expression (n = 66) is associated with low p21 (n = 82; P < 0.001) and low p16 (n = 86; P < 0.001) levels. In conclusion, this study demonstrated that NDRG1 is a potential therapeutic target for HCC because its suppression triggers senescence of HCC cells through activating glycogen synthase kinase-3ß-p53 pathway, thereby inhibiting tumor progression.

Molecular imaging of hepatocellular carcinoma xenografts with epidermal growth factor receptor targeted affibody probes.

Hepatocellular carcinoma (HCC) is a highly aggressive and lethal cancer. It is typically asymptomatic at the early stage, with only 10%-20% of HCC patients being diagnosed early enough for appropriate surgical treatment. The delayed diagnosis of HCC is associated with limited treatment options and much lower survival rates. Therefore, the early and accurate detection of HCC is crucial to improve its currently dismal prognosis. The epidermal growth factor receptor (EGFR) has been reported to be involved in HCC tumorigenesis and to represent an attractive target for HCC imaging and therapy. In this study, an affibody molecule, Ac-Cys-ZEGFR:1907, targeting the extracellular domain of EGFR, was used for the first time to assess its potential to detect HCC xenografts. By evaluating radio- or fluorescent-labeled Ac-Cys-ZEGFR:1907 as a probe for positron emission tomography (PET) or optical imaging of HCC, subcutaneous EGFR-positive HCC xenografts were found to be successfully imaged by the PET probe. Thus, affibody-based PET imaging of EGFR provides a promising approach for detecting HCC in vivo.

Education and counseling of pregnant patients with chronic hepatitis B: perspectives from obstetricians and perinatal nurses in Santa Clara County, California.

BACKGROUND: This study aimed to better understand the barriers to perinatal hepatitis B prevention and to identify the reasons for poor hepatitis B knowledge and delivery of education to hepatitis B surface-antigen- positive pregnant women among healthcare providers in Santa Clara County, California. MATERIALS AND METHODS: Qualitative interviews were conducted with 16 obstetricians and 17 perinatal nurses in Santa Clara County, California, which has one of the largest populations in the United States at high risk for perinatal hepatitis B transmission. RESULTS: Most providers displayed a lack of self-efficacy attributed to insufficient hepatitis B training and education. They felt discouraged from counseling and educating their patients because of a lack of resources and discouraging patient attitudes such as stigma and apathy. Providers called for institutional changes from the government, hospitals, and nonprofit organizations to improve care for patients with chronic hepatitis B. CONCLUSIONS: Early and continuing provider training, increased public awareness, and development of comprehensive resources and new programs may contribute to reducing the barriers for health care professionals to provide counseling and education to pregnant patients with chronic hepatitis B infection.

Low levels of knowledge and preventive practices regarding vertical hepatitis B transmission among perinatal nurses.

OBJECTIVE: To evaluate current levels of hepatitis-B-related knowledge and clinical practice among perinatal nurses. DESIGN: Cross-sectional study. SETTING: Santa Clara County, California, home to one of the largest U.S. populations at risk of perinatal hepatitis B transmission. PARTICIPANTS: Perinatal nurses (N = 518) from eight birthing hospitals. METHODS: In 2008-2010, nurses completed a baseline survey evaluating existing hepatitis-B-related knowledge and preventive clinical practices, participated in an educational seminar, received instructional materials about hepatitis B, and completed a follow-up knowledge survey. RESULTS: Eighty percent of perinatal nurses had provided health care to a pregnant woman with chronic hepatitis B, but only 51% routinely provided patients with educational information about hepatitis B. While 75% routinely informed patients about effective methods to prevent mother-to-child transmission, only a small minority (17-34%) educated infected women about standard recommendations for protecting themselves and household members. One fourth or fewer nurses correctly answered most questions about hepatitis B prevalence, risks, and symptoms. After the educational seminar, knowledge increased statistically significantly. CONCLUSION: Existing knowledge about hepatitis B is limited, and nationally recommended preventive clinical practices are commonly overlooked by perinatal nurses. This lack of knowledge and preventive care represents a noteworthy gap and an opportunity for targeted training and education to improve perinatal hepatitis B prevention and medical management of infected mothers.

The CD47-signal regulatory protein alpha (SIRPa) interaction is a therapeutic target for human solid tumors.

CD47, a "don't eat me" signal for phagocytic cells, is expressed on the surface of all human solid tumor cells. Analysis of patient tumor and matched adjacent normal (nontumor) tissue revealed that CD47 is overexpressed on cancer cells. CD47 mRNA expression levels correlated with a decreased probability of survival for multiple types of cancer. CD47 is a ligand for SIRPα, a protein expressed on macrophages and dendritic cells. In vitro, blockade of CD47 signaling using targeted monoclonal antibodies enabled macrophage phagocytosis of tumor cells that were otherwise protected. Administration of anti-CD47 antibodies inhibited tumor growth in orthotopic immunodeficient mouse xenotransplantation models established with patient tumor cells and increased the survival of the mice over time. Anti-CD47 antibody therapy initiated on larger tumors inhibited tumor growth and prevented or treated metastasis, but initiation of the therapy on smaller tumors was potentially curative. The safety and efficacy of targeting CD47 was further tested and validated in immune competent hosts using an orthotopic mouse breast cancer model. These results suggest all human solid tumor cells require CD47 expression to suppress phagocytic innate immune surveillance and elimination. These data, taken together with similar findings with other human neoplasms, show that CD47 is a commonly expressed molecule on all cancers, its function to block phagocytosis is known, and blockade of its function leads to tumor cell phagocytosis and elimination. CD47 is therefore a validated target for cancer therapies.

A model program for hepatitis B vaccination and education of schoolchildren in rural China.

OBJECTIVES: Incomplete hepatitis B virus (HBV) vaccine coverage and poor HBV-related knowledge in China leave millions of children unprotected from this life-threatening infection. To address these gaps, a pilot program for HBV education and vaccination was launched in rural China. METHODS: In 2006, public and private organizations in the US and China collaborated to provide HBV education and vaccination to 55,000 school-age children in the remote, highly HBV-endemic area of Qinghai Province. The impact of the educational program on HBV-related knowledge was evaluated among more than 2,800 elementary school students. RESULTS: Between September 2006 and March 2007, the three-shot hepatitis B vaccine series was administered to 54,680 students, with a completion rate of 99.4%. From low pre-existing knowledge levels, classroom educational sessions statistically significantly increased knowledge about HBV risks, symptoms, transmission, and prevention. CONCLUSIONS: This program offers an effective and sustainable model for HBV catch-up vaccination and education that can be replicated throughout China, as well as in other underserved HBV-endemic regions, as a strategy to reduce chronic HBV infection, liver failure, and liver cancer.

Suppression of glypican 3 inhibits growth of hepatocellular carcinoma cells through up-regulation of TGF-ß2.

Glypican 3 (GPC3) is a valuable diagnostic marker and a potential therapeutic target in hepatocellular carcinoma (HCC). To evaluate the efficacy of targeting GPC3 at the translational level, we used RNA interference to examine the biologic and molecular effects of GPC3 suppression in HCC cells in vitro and in vivo. Transfection of Huh7 and HepG2 cells with GPC3-specific small interfering RNA (siRNA) inhibited cell proliferation (P < .001) together with cell cycle arrest at the G(1) phase, down-regulation of antiapoptotic protein (Bcl-2, Bcl-xL, and Mcl-1), and replicative senescence. Gene expression analysis revealed that GPC3 suppression significantly correlated with transforming growth factor beta receptor (TGFBR) pathway (P = 4.57e-5) and upregulated TGF-ß2 at both RNA and protein levels. The effects of GPC3 suppression by siRNA can be recapitulated by addition of human recombinant TGF-ß2 to HCC cells in culture, suggesting the possible involvement of TGF-ß2 in growth inhibition of HCC cells. Cotransfection of siRNA-GPC3 with siRNA-TGF-ß2 partially attenuated the effects of GPC3 suppression on cell proliferation, cell cycle progression, apoptosis, and replicative senescence, confirming the involvement of TGF-ß2 in siRNA-GPC3-mediated growth suppression. In vivo, GPC3 suppression significantly inhibited the growth of orthotopic xenografts of Huh7 and HepG2 cells (P < .05), accompanied by increased TGF-ß2 expression, reduced cell proliferation (observed by proliferating cell nuclear antigen staining), and enhanced apoptosis (by TUNEL staining). In conclusion, molecular targeting of GPC3 at the translational level offers an effective option for the clinical management of GPC3-positive HCC patients.