Abstract B40: Suppression of Stat3 inhibits the invasive potential of malignant squamous cell carcinoma by interfering with the HGF/cmet/Stat3 signaling pathway

Cancer cell invasion and induction of the metastatic cascade are often the consequence of deregulated cell adhesion and migration. There is substantial evidence for the involvement of Stat3 in cell motility, migration, and invasion under normal and pathological situations. Stat3 activation is required for induction of genes encoding MMP-1, MMP-2, and MMP-9, key components of tumor invasion. Through binding to its receptor, cmet, hepatocyte growth factor (HGF) can regulate cell survival, growth, migration, and angiogenesis. cmet is often constitutively active in human tumors and HGF/cmet signaling is at least partially mediated by Stat3. Overall, these observations suggest that positive feedback signals in the HGF/cmet/Stat3 signaling pathway contribute to tumorigenesis.

To explore the role of Stat3 in skin cell malignancy in a human cell culture model, our lab has overexpressed a dominant negative form of Stat3β in the tumorigenic SCC cell line, SRB12-p9. We established SRB12-p9 cell clones expressing FLAG-tagged Stat3β-Y705F (S3DN). Suppression of Stat3 activity impaired the ability of these cells to scatter upon stimulation with HGF, diminished their capacity to invade, and enhanced adhesion in vitro. S3DN cells also showed suppressed HGF-induced activation of cmet, as revealed by a phospho-specific cmet antibody. We next assessed the role of Stat3 in tumor invasion using in vivo mouse tumorigenicity experiments. When injected subcutaneously into immune-deficient mice, S3DN cells produced tumors that were less locally invasive, though WT tumors were more differentiated as indicated by K10 immunostaining. Upon further examination of these tumors, we found that those arising from WT cells had more intense membrane staining for total cmet and phospho-cmet than S3DN cells, indicating stronger cmet activity in these tumors. This pattern of cmet staining correlated with increased phospho-Stat3 membrane staining in the WT tumors. Western blotting revealed a decrease in MMP-2, MMP-9, and cmet expression in the S3DN cells. These results are consistent with those from the in vitro experiments. Finally, we show that S3DN may interfere with Stat3/cmet interaction, as evidenced by co-immunoprecipitation experiments, preventing the activation of cmet at the cell membrane. Ongoing studies will further address the effect of S3DN expression on cmet signaling and the effect this has on the HGF/c-met/Stat3 signaling loop and tumor cell invasion.

Citation Information: Cancer Prev Res 2010;3(1 Suppl):B40.

Intermittent Hypoxia: Potential Factor of Resistance to Endocrine Therapy

Background: It has been reported that intermittent hypoxia, which is likely more prevalent than acute hypoxia in breast cancers, can cause persistent depression of estrogen receptor alpha (ER-α) expression in breast cell lines. However, it remains suspension whether intermittent hypoxia may be associated with resistance to endocrine therapy.Material and methods: The role of intermittent hypoxia in resistance to endocrine therapy was investigated in ER-α positive breast cell lines and animal models.Results: We observed that intermittent hypoxia promoted cancer cell proliferation in vitro and in vivo compared with normoxia. At both mRNA and protein levels, intermittent hypoxia induced down-regulation of ER-α and factor inhibiting HIF-1 (FIH) as well as up-regulation of hypoxia inducible factor-1 alpha (HIF-1α) and carbonic anhydrase IX (CA-IX). ER-α positive breast cancer cells under normoxic condition were capable of an intact response to ICI 182,780 (Tocris), whereas the inhibitory effect of ICI 182,780 (Tocris) was significantly reduced in those after intermittent hypoxia. Such effect was further validated with fulvestrant (Astrazeneca) in the animal models. To clarify whether intermittent hypoxia was associated with resistance to endocrine therapy, the expression of HIF-1α, a critical regulator of hypoxia-related pathway, was blocked by a reformed type of small interfering RNA (siRNA), stealth RNAi (Invitrogen), which can reduce the cytotoxic interferon response unlike conventional siRNA. Interestingly, knock-down of HIF-1α did result in the restoration of not only the ER-α expression but also the response to endocrine therapy, which was reproducible with administration of Bortezomib, a proteasome inhibitor of HIF-1α.Discussion: These data provide functional evidence that intermittent hypoxia may confer resistance to endocrine therapy in breast cancers through the crosstalk between HIF-1α and ER-α signaling, which holds a promise to overcome endocrine resistance.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5148.

Epidemiology of Triple Negative Breast Cancer in China

Background:The classification of tumors based on the gene expression may define intrinsic breast cancer subtypes in which the effect of risk factors could be more obvious. We sought to assess the risk factors for triple negative breast cancer on Chinese population.Methods: A retrospective study of 5761 patients was carried out from a large database of breast cancer patients undergoing surgery between January 1, 1991 and June 31, 2008 in Cancer Hospital, Fudan University, Shanghai, China. Univariate analyses were performed by chi-square test of Student's t test and multivariate analyses by logistic regression.Results: A total of 1108 women were identified as having triple negative breast cancer and were compared with the 4653 women with non-triple negative. Regardless the pathological discrepancy, women with triple negative breast cancers were significantly more likely to be younger age(P=0.001; OR=1.615, 95%CI=1.207-2.160), premenopausal (P = 0.003; OR = 1.570, 95% CI = 1.171-2.106) and parous women (P = 0.001; OR = 1.741, 95% CI = 1.269-2.387).There seems no associations with increasing risk of triple negative breast cancer for breastfeeding (P=0.126), younger age at menarche (P=0.129), first degree family history (P=0.111) and oral contraceptive usage (P=0.251).Conclusion:Based on this large population study in Chinese breast cancer patients, the risk factors for triple negative phenotype may be somewhat different from those for Western women. Therefore, a better knowledge of this issue is warranted due to it may have impact on clinical outcomes and may offer some insight into the process of carcinogenesis and therapeutic efficacy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2065.

Oxidative stress inhibits insulin-like growth factor-I induction of chondrocyte proteoglycan synthesis through differential regulation of phosphatidylinositol 3-Kinase-Akt and MEK-ERK MAPK signaling pathways

The ability of insulin-like growth factor I (IGF-I) to stimulate cartilage matrix synthesis is reduced in aged and osteoarthritic cartilage. Aging and osteoarthritis are associated with an increase in reactive oxygen species, which we hypothesized would interfere with normal IGF-I signaling. We compared IGF-I signaling in normal and osteoarthritic human articular chondrocytes and investigated the effects of oxidative stress induced by tert-butylhydroperoxide (tBHP). In normal human chondrocytes, IGF-I initiated a strong and sustained phosphorylation of IRS-1 (Tyr-612) and Akt (Ser-473) and transient ERK phosphorylation. In contrast, in osteoarthritic chondrocytes, which possessed elevated basal IRS-1 (Ser-312) and ERK phosphorylation, IGF-I failed to stimulate IRS-1 (Tyr-612) or Akt phosphorylation. In normal human chondrocytes, tBHP triggered strong IRS-1 (Ser-312 and Ser-616) and ERK phosphorylation and inhibited IGF-I-induced IRS-1 (Tyr-612) and Akt phosphorylation. Lentivirus-mediated overexpression of constitutively active (CA) Akt significantly enhanced proteoglycan synthesis, whereas both dominant negative Akt and CA MEK inhibited proteoglycan synthesis. CA Akt also promoted type II collagen and Sox9 expression, whereas tBHP treatment and CA MEK inhibited aggrecan, collagen II, and Sox9 mRNA expression. In osteoarthritic chondrocytes, the antioxidants Mn(III) tetrakis(4-benzoic acid)porphyrin and N-acetylcysteine increased the ratio of Akt to ERK phosphorylation and promoted IGF-I-mediated proteoglycan synthesis. Chemical inhibition of ERK significantly enhanced IGF-I phosphorylation of Akt and alleviated tBHP inhibition of Akt phosphorylation. These results demonstrate opposing roles for phosphatidylinositol 3-kinase-Akt and MEK-ERK in cartilage matrix synthesis and suggest that elevated levels of reactive oxygen species cause chondrocyte IGF-I resistance by altering the balance of Akt to ERK activity.

Serum complement activation on heterologous platelets is associated with arterial thrombosis in patients with systemic lupus erythematosus and antiphospholipid antibodies

Complement plays a major role in inflammation and thrombosis associated with systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS). A cross-sectional retrospective analysis was performed to evaluate serum complement fixation on platelets and thrombotic incidence using banked sera and clinical data from patients with SLE (n = 91), SLE with antiphospholipid antibodies (aPL) or APS (n = 78) and primary aPL (n = 57) or APS (n = 96). In-situ complement fixation was measured as C1q and C4d deposition on heterologous platelets using an enzyme-linked immunosorbent assay approach. Platelet activation by patient serum in the fluid phase was assessed via serotonin release assay. Enhanced in-situ complement fixation was associated with the presence of IgG aPL and IgG anti-beta2 glycoprotein 1 antibodies (P < 0.05) and increased platelet activation (P < 0.005). Moreover, enhanced complement fixation, especially C4d deposition on heterologous platelets, was positively associated with arterial thrombotic events in patients with SLE and aPL (P = 0.039). Sera from patients with aPL possess an enhanced capacity for in-situ complement fixation on platelets. This capacity may influence arterial thrombosis risk in patients with SLE.

Activity and radiation protection studies for the W-Ta target of CSNS

The Chinese government initiated a conceptual design for the project of China Spallation Neutron Source (CSNS), which consists of an H-linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a target station converting proton beam into lower energy (<1 eV) neutron beam optimised to instruments for neutron scattering applications. The facility operates at 25-Hz repetition rate with an initial beam power of 100 kW. In the target station, the target-moderator-reflector (TMR) components are exposed to the intensive fluxes of high-energy hadrons and become highly radioactive as a result of long-time irradiation. In this paper, the activity of the TMR components are calculated using the Monte Carlo code system LAHET&MCNP4C&CINDER'90. Comparisons of some results with that simulated by FLUKA code are also performed. Detailed analyses of the radionuclides and their characters in the tantalum clad tungsten target (W-Ta target) are important for the radiation protection of the CSNS target station. The shielding design of the service cell for the decay gamma ray induced from the W-Ta target and its vessel shows that the ambient dose rate decreases exponentially with increasing heavy concrete thickness. And 80 cm thickness of heavy concrete for each side of the service cell can satisfy the safety requirement.

Phylogeographical analysis of an estuarine fish, Salanx ariakensis (Osmeridae: Salanginae) in the north-western Pacific

This study extended the geographic coverage of a previous study to explore population genetic structure and demographic history in the Ariake icefish Salanx ariakensis from three populations of continental coastlines and one island population in the north-western Pacific based on a partial sequence of the mitochondrial cytochrome b gene. The S. ariakensis showed high genetic diversity and strong genetic structure. Phylogenetic analysis showed a shallow gene tree with no clear phylogeographical structure. Contiguous range expansion and restricted gene flow were inferred to be main population events by nested-clade analysis. Significant genetic differentiations between populations could be attributable to negligible gene flow by coalescent analysis. High nucleotide diversity of each population was due to geographic mixing of heterogenous haplotypes during lowering sea levels of the Pleistocene. These findings indicate that cycles of geographic isolation and secondary contact happened in the Pleistocene glacial-interglacial cycles shaping genetic structure and population demography of S. ariakensis.

Linear growth patterns in prepubertal children following liver transplantation

Factors impacting linear growth following pediatric liver transplantation (LT) are not well understood. This longitudinal analysis examines predictors of linear growth impairment in prepubertal children included in Studies of Pediatric Liver Transplantation. In 1143 children with serial measurements, mean height scores increased from -1.55 at LT to -0.87 and -0.68 at 24 and 36 months post LT with minimal subsequent catch up growth observed until 60 months. Subgroup analysis of height measurements at 24 months (n = 696), 33.8% were below 10th percentile at 24 months post LT. Multivariate analysis revealed linear growth impairment more likely in patients with metabolic disease (OR 4.4, CI: 1.83-10.59) and >18 months of steroids exposure (OR 3.02, CI: 1.39-6.55). Higher percentiles for weight (OR 0.80, CI: 0.65-0.99) and height (OR 0.62, CI: 0.51-0.77) at LT decreased risk. Less linear catch up was observed in patients with metabolic disease, non-Biliary atresia cholestatic diseases and lower weight and higher height percentiles prior to LT. Prolonged steroid exposure and elevated calculated glomerular filtration rate and gamma-Glutamyltransferase following LT were associated with less catch up growth. Linear growth impairment and incomplete linear catch up growth are common following LT and may improve by avoiding advanced growth failure before LT and steroid exposure minimization.

Postsurgical drainage and the risk of breast cancer recurrence in Chinese breast cancer patients

e22234

Background: Clinical investigations suggest that while primary breast cancer surgical removal favorably modifiers the natural history of breast cancer. Postoperative drainage, a surgery-derived discharge after breast cancer surgery, reflecting some biological features of surgical stimulation, was assessed and explored its relationship with breast cancer recurrence in this study. Methods: A total of 1445 women undergoing surgery between Jan 1, 2000 and Dec31, 2002 in Cancer Hospital of Fudan University, Shanghai, China was retrospectively studied. Survival curves were performed with Kaplan-Meier method and the predictive value of postsurgical drainage was estimated using proportional Cox regression model. Conclusions: The larger drainage volume POD 1 is a useful marker, suggesting a greater stimulation to surgical treatment compared to the lower ones. Awareness of the relationship between early surgery-stimulated effects and harmful wound healing response might help to explore new strategies to block or deplete these harmful effects, resulting in improving patients' survival.

No significant financial relationships to disclose.

Demographic features and prognostic profiles of breast cancer patients presenting with nipple discharge in Chinese population

e22204

Background: Breast cancer patients with nipple discharge (ND) may constitute a distinct clinical entity compared to those without ND, which has not been well elucidated in previous reports. We sought to analyze the demographic features and prognostic profiles of breast cancer patients presenting with nipple discharge in Chinese population. Methods: A total of 3234 patients, categorized as ND (2.47%) and non-nipple discharge (NND; 97.53%) according to different initial signs, were retrospectively analyzed. Survival curves were performed with Kaplan-Meier method and annual recurrence hazard was estimated by hazard function. Results: ND group tended to have smaller tumors and less axillary lymph node (ALN) involvement than NND group (P < 0.05). In the univariate analysis, we found significantly different recurrence-free survivals (RFS) between subgroups (P = 0.0182), with the rate of 77.78% for ND group and 72.46% for the other at the 11th year respectively. In Cox proportional hazards regression analysis, we found that tumor size (P < 0.001), ALN status (P < 0.001) were independent prognostic factors for RFS. To further evaluate whether prognostic effect of ND status remained unabated over time, the test for lack of proportionality was performed. However, it was statistically significant (global test, P = 0.039), which hinted at a demand for the employment of Cox non-proportional hazards regression in this analysis. In time dependent Cox model, ND status (P = 0.0495) as well as ERBB2 status (P = 0.017), tumor size (P < 0.001), ALN status (P < 0.001) were independent prognostic factors when ND and ERBB2 status were taken as time-varying covariates. Annual hazard rates for recurrence remained lower on ND group until approximately 4.5 years after surgery, while the situation was just the opposite thereafter. Conclusions: Our findings suggested that demographic features and prognostic profiles were quite different between breast cancers presenting with and without ND in Chinese population, which may indirectly uncover distinct biological behaviors and potentially enlighten novel therapeutic approaches for patients with different initial signs.

No significant financial relationships to disclose.

Identification of the B-Raf/Mek/Erk MAP kinase pathway as a target for all-trans retinoic acid during skin cancer promotion

Background

Retinoids have been studied extensively for their potential as therapeutic and chemopreventive agents for a variety of cancers, including nonmelanoma skin cancer (NMSC). Despite their use for many years, the mechanism of action of retinoids in the prevention of NMSC is still unclear. In this study we have attempted to understand the chemopreventive mechanism of all-trans retinoic acid (ATRA), a primary biologically active retinoid, in order to more efficiently utilize retinoids in the clinic.

Results

We have used the 2-stage dimethylbenzanthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA) mouse skin carcinogenesis model to investigate the chemopreventive effects of ATRA. We have compared the gene expression profiles of control skin to skin subjected to the 2-stage protocol, with or without ATRA, using Affymetrix 430 2.0 DNA microarrays. Approximately 49% of the genes showing altered expression with TPA treatment are conversely affected when ATRA is co-administered. The activity of these genes, which we refer to as 'counter-regulated', may contribute to chemoprevention by ATRA. The counter-regulated genes have been clustered into functional categories and bioinformatic analysis has identified the B-Raf/Mek/Erk branch of the MAP kinase pathway as one containing several genes whose upregulation by TPA is blocked by ATRA. We also show that ATRA blocks signaling through this pathway, as revealed by immunohistochemistry and Western blotting. Finally, we found that blocking the B-Raf/Mek/Erk pathway with a pharmacological inhibitor, Sorafenib (BAY43-9006), induces squamous differentiation of existing skin SCCs formed in the 2-stage model.

Conclusion

These results indicate that ATRA targets the B-Raf/Mek/Erk signaling pathway in the 2-stage mouse skin carcinogenesis model and this activity coincides with its chemopreventive action. This demonstrates the potential for targeting the B-Raf/Mek/Erk pathway for chemoprevention and therapy of skin SCC in humans. In addition our DNA microarray results provide the first expression signature for the chemopreventive effect of ATRA in a mouse skin cancer model. This is a potential source for novel targets for ATRA and other chemopreventive and therapeutic agents that can eventually be tested in the clinic.

Seroma formation after breast cancer surgery and its risk factors

Abstract #4085

Background:. Seroma formation is one of the most common complications after breast cancer surgery including modified radical mastectomy and breast conservative surgery. Our study aims to investigate the risk factors of postoperative seroma in Chinese breast cancer patients.&#x2028; Methods: Clinical data of 158 women who underwent surgerical therapy for breast cancer in our hospital were collected prospectively and all patients were followed up. The risk factors for seroma occurrence were compared between the seroma group and control group using X 2 test or t test, as well as the logistic regression was used as multivariate analysis.&#x2028; Results: Univariate analysis showed that the average age of the seroma group was significantly higher than those without seroma formation(58.71vs51.00, P=0.0019), but the total serum protein and albumin content were lower (68.47g/L vs 72.53g/L, P=0.009 and 40.75g/L vs 42.52g/L,P=0.020, respectively). In seroma group, the drainage volume of the first three days, the total and daily drainage volume were all higher (all p values less than 0.01), as well as drainage duration and hospital stay were longer(8.3d vs 14.4d, P=0.000 and 11.5d vs 23.7d, P=0.000, respectively). Logistic regression showed that older patients (OR=1.080, 95%CI 1.016∼1.148, P=0.013), lower total serum protein content(OR=0.814, 95%CI 0.705∼0.940, P=0.005)and higher drainage volume in d1(OR=1.009, 95%CI 1.001∼1.016, P=0.022) and d3 (OR=1.017, 95%CI 1.005∼1.029, P=0.005) were all independent risk factors for subcutaneous seroma. The daily average drainage curve showed a gradually decreasing trend with a highest collections in the first three days. The seroma group had significantly higher average daily drainage volume( P=0.034) and longer duration (P=0.000).&#x2028; Conclusion:The risk factors of seroma formation after breast cancer surgery are complicated. However in order to prevent its occurrence effectively, the factors including age, nutrition status and daily drainage volume should be taken into consideration.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4085.

Clinicopathological features of the triple-negative tumors in Chinese breast cancer patients

Abstract #6080

Background: Triple negative breast cancers are defined by a lack of expression of estrogen, progesterone, and Her-2 receptors. A number of studies suggested that the triple-negative phenotype could contribute to an aggressive behavior and a poor prognosis. However, similar data is still not available for Chinese populations. We sought to analyze the clinicopathological features of this subgroup in our hospital in order to get characteristics for Chinese breast cancer.&#x2028; Methods: We performed a retrospective study of 2028 female unilateral breast cancer patients undergoing surgery in our hospital from February 1991 to December 2003. ER, PR and Her-2 status were assessed using immunohistochemical staining. Survival curves were performed with Kaplan-Meier method and annual recurrence hazard was estimated by hazard function.&#x2028; Results: According to different combinations of hormone receptor (HR) and Her-2 status, 2028 patients were categorized into the three subgroups as follows: Her-2+ (32.25%), HR+/Her-2- (48.92%) and triple-negative (18.83%). Triple-negative tumors were larger (greater than 2 cm in diameter) than HR+/Her-2- tumors, but smaller than Her-2+ tumors (70.03%, 66.15% and 76.15% respectively, P &lt; 0.001). In addition, 21.99% of patients whose tumors were triple-negative had four or more axillary nodes involved compared with 27.37% of patients with Her-2+ tumors and 22.78% with HR+/Her-2- tumors (P = 0.004). There were statistical differences in the distribution of TP53 mutation and Cathepsin-D status (P &lt; 0.001 for both). In the univariate analysis, we found a statistical significance for recurrence-free survival (RFS) among the three subgroups (P = 0.0036), with the rate of 72.89% for Her-2+ tumors, 78.26% for HR+/Her-2- tumors and 75.61% for triple-negative tumors at the 11th year respectively. When it came to the time of hazard peaks, discrepancies existed in different subgroups. Triple-negative patients showed an early major recurrence surge peaking at the 2.5th year after surgery, followed by a gradual decline until year 6.5 and then a modest increase. As to HR+/Her-2- patients, the hazard plot exhibited a wide initial plateau-like wave covering at least 4 years and a subsequent rise. The hazard rate for Her-2+ patients displayed a tapering sharp at the 1st year and a second rise. Furthermore, the first peak of triple-negative tumors was higher than that of HR+/Her-2- patients, but lower than that of Her-2+ ones.&#x2028; Conclusions: The recurrence pattern for triple-negative tumors was intermediate between Her-2+ and HR+/Her-2- counterparts.Our findings suggested that biological characteristics and prognosis of Chinese triple-negative breast cancer might be more favorable and somewhat different from those in Western populations.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6080.

Time distributions and prognosis factors of breast cancer recurrence in different sites after operation

Abstract #2080

Objective Our study aims to analyze the breast caner patients with different sites of recurrence, and to have knowledge of the regular patterns and influence factors of metastastic breast cancer.&#x2028; Methods We performed a retrospective study of 210 female breast cancer patients who were continuously followed up in our hospital from January 2005 to May 2007 and had complete data of metastasis. The clinical and biological characteristics were compared between the patients with organ metastases (lung, liver, brain) and non-viscera metastases (lymph node, bone).&#x2028; Results Cox regression analysis-hazard function showed that patients with elder age (RR=0.927 95%CI 0.877∼0.981, P=0.008) and HER-2 negative(RR=0.253 95%CI 0.076∼0.836, P=0.024)tended to develop non-viscera metastases, while patients with larger tumors (RR=3.832 95%CI 1.073∼13.687, P=0.039) tended to develop organ metastasesp.&#x2028; &#x2028; When stratified by the prognostic factors, the annual risk hazard curve of the patients with high risk of recurrence had double peaks at the second year and the ninth years after mastectomy respectively, and it was significantly higher than those of the patients with middle and low risk.[figure1]Annual risk hazard curves of both local relapse and metastasis also showed a double-peaked pattern. The curves for lymph node, bone, lung and liver metastasis showed a similar pattern, but all the peaks of curve emerged later than that of the local relapse.&#x2028; &#x2028; Conclusion Patients with different clinical and biological characteristics may develop recurrence in different sites. There are certain regular patterns of time distribution for different metastasis sites after mastectomy. The local recurrence may be the foreboding for the metastasis and we should pay attention to the local relapse signs especially in the patients with high risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2080.

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Scavenger Receptor Class B Type I Mediates Cell Entry of Hepatitis C Virus

This study assessed the functional role of human scavenger receptor class B type I (SR-BI) as a putative hepatitis C virus (HCV) receptor using Chinese hamster ovary (CHO) cells transfected with human SR-BI (CHO–huSR-BI). The expression of SR-BI by primary Tupaia hepatocytes (PTHs), human hepatocarcinoma cell line (HepG2) cells, untransfected CHO cells and CHO–huSR-BI cells was analysed by Western blotting. Receptor competition assays showed that anti-SR-BI antibodies that block the binding of soluble envelope glycoprotein E2 could prevent HCV infection. Pre-incubation of CHO–huSR-BI and HepG2 cells with anti-SR-BI antibodies resulted in marked inhibition of E2 binding. After incubation with HCV RNA-positive serum from a patient with chronic HCV infection, however, HCV infection could not be detected in CHO–huSR-BI cells, but was detected in PTHs. These results demonstrate that, whilst SR-BI represents an important cell surface molecule for HCV infection, the presence of SR-BI alone is insufficient for HCV entry.

A novel hepatitis C virus vaccine approach using recombinant Bacillus Calmette-Guerin expressing multi-epitope antigen

Hepatitis C virus (HCV) is a major cause of liver disease worldwide. HCV infection is associated with high morbidity and has become a major problem in public health. Until now, there has been no effective prophylactic or therapeutic vaccine. BCG, a live vaccine typically used for tuberculosis prevention, has been increasingly utilized as a vector for the expression of recombinant proteins that will induce specific humoral and cellular immune responses. In this study, recombinant BCG (rBCG) was engineered to express a HCV multi-epitope antigen CtEm, and HLA-A2.1 transgenic mice were immunized with rBCG-CtEm. High levels of specific anti-HCV antibodies targeted to mimotopes of HVR1 were detected in the serum. HCV-specific lymphocyte proliferation assay, cytokine determination and cytotoxicity assay indicated that HCV epitope-specific cellular immune responses were elicited in vitro. The rBCG-CtEm immunization conferred protection against infection with the recombinant vaccinia virus (rVV-HCV-CNS) in vivo. These results suggest that rBCG expressing multi-epitope antigen may serve as an effective vaccine against HCV infection.