PD-1 inhibitor plus oncolytic vaccinia virus is a safe and effective treatment option for metastatic renal cell carcinoma

BACKGROUND

Although a combination of immune checkpoint inhibitors (ICIs) is recommended as the first line treatment option for metastatic renal cell carcinoma (mRCC), several immune-related adverse events (irAEs) occur, especially hepatitis. We explored the therapeutic benefits and safety profile of combining oncolytic vaccinia virus, JX-594, with a programmed cell death protein-1 (PD-1) inhibitor.

METHODS

We used early-stage and advanced-stage orthotopic murine mRCC models developed by our group. PD-1 inhibitor monotherapy or a PD-1 inhibitor combined with either JX-594 or a cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) inhibitor were systemically injected through the peritoneum. An immunofluorescence analysis was performed to analyze the tumor immune microenvironment (TIME). irAEs were assessed in terms of hepatitis.

RESULTS

In the early-stage mRCC model mice, the combination of JX-594 and a PD-1 inhibitor significantly decreased the primary tumor size and number of lung nodules, compared with the ICI combination, but the JX-594 and PD-1 inhibitor combination and ICI combination did not differ significantly in the advanced-stage mRCC model mice. The JX-594 and PD-1 inhibitor combination induced tumor-suppressing TIME changes in both the early- and advanced-stage mRCC models. Furthermore, mice treated with the ICI combination had significantly greater hepatic injuries than those treated with the JX-594 and PD-1 inhibitor combination which was evaluated in early-stage mRCC model.

CONCLUSIONS

The JX-594 and PD-1 inhibitor combination effectively reduced primary tumors and the metastatic burden, similar to ICI combination therapy, through dynamic remodeling of the TIME. Furthermore, hepatitis was significantly decreased in the JX-594 and PD-1 inhibitor combination group, suggesting the potential benefit of that combination for reducing ICI-induced toxicity.

Predictive biomarkers for the oncolytic virus, JX-594, through the HIF-dependent interferon beta pathway in metastatic renal cell carcinoma

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Background: Although combination approaches with an immunotherapy are established as the first-line setting in metastatic renal cell carcinoma (mRCC), immunotherapy are only efficacious for a subset of patients. Our group has been working on improving the benefit of immunotherapy using JX-594 (pexastimogene devacirepvec, Pexa-vec) in mRCC. The purpose of this study is to develop predictive biomarker for JX-594 in metastatic clear cell RCC (ccRCC). Methods: Using ccRCC cell lines representative of each four mutations (786-O (VHL mutation), Caki-2 (VHL and PBRM1 mutation), A-498 (VHL and SETD2 mutation), and 769-P (VHL and BAP1 mutation)), four cell line-derived xenograft (CDX) mouse models have been developed. 2-10x106 tumor cells were subcutaneously injected into the right flank of wild-type BALB/c nude mice. When tumors reached >50 mm3, mice were treated with either PBS or 1x107 plaque-forming units of JX-594 by intratumoral injection in day 0, 3, and 6. Interferon beta (IFN-β) expression were measured with qRT-PCR after the JX-594 treatment in 786-O CDX model. Results: All CDX models demonstrated significant decrease in tumor size by the JX-594 compared to control. Most rapid tumor growth was observed in BAP1-deficient xenografts while PBRM1-deficient xenografts demonstrated the slowest growth among four xenografts. The decrease of tumor volume by the JX-594 was most pronounced in BAP1-deficient tumors compared to VHL, PBRM1, and SETD2 mutation tumors. Even after adjusting the relative differences of tumor growth rate in each model, xenografts with BAP1 loss were still associated with significantly better response to JX-594. IFN-β expression significantly decreased in BAP1-deficient tumors compared to other tumors, while the expression level was recovered dramatically after JX-594. Conclusions: BAP1-deficient tumors demonstrated rapid tumor progression while they were most significantly reduced after JX-594. BAP1-deificient tumors had decreased levels of IFN-β expression while it was most dramatically recovered after JX-594, suggesting the mechanism of JX-594 through the HIF-dependent interferon beta induction. This is the first study to elucidate the potential of BAP1 as predictive biomarker for JX-594 and its underlying mechanisms.

Anti-PD1 plus oncolytic virus as first-line treatment option for metastatic renal cell carcinomas

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Background: Although anti-programmed death (PD)1 and anti-cytotoxic T-cell lymphocyte (CTLA)-4 combination therapy is recommended as one of the first line treatment options for metastatic renal cell carcinoma (mRCC), immune checkpoint inhibitor (ICI) combination therapy leads to the increased immune-mediated adverse events (imAEs). Our group has reported the therapeutic potential of oncolytic virus, JX-594 in metastatic murine RCC model. In this study, we explored the effect of JX-594 plus anti-PD1 in comparison to the combination therapy of anti-PD1 and anti-CTLA-4. Methods: Early-stage and advanced-stage highly metastatic orthotopic murine RCC models developed by our group were used. Anti-PD1 with either JX-594 or anti-CTLA-4 were systemically injected through the peritoneum. Immunofluorescence analysis was performed to demonstrate the remodeling of the tumor immune microenvironment (TIME). Results: Both JX-594 plus anti-PD1 and ICI combination therapy significantly reduced primary tumor and metastatic tumor burden in lung and peritoneum compared to cytoreductive nephrectomy plus anti-PD1. For the early-stage and advanced-stage mRCC models, JX-594 plus anti-PD1 significantly decreased the primary tumor sizes and number of lung tumor nodules compared to ICI combination therapy only in the early-stage mRCC model ( P<0.01), but not in advanced-stage mRCC model ( P=0.07). The therapeutic benefit was significantly increased when JX-594 and anti-PD1 was sequentially injected compared to when JX-594 and anti-PD1 was injected simultaneously ( P<0.05). Notable imAEs were observed in 2/16 (12.5%) in ICI combination group, whereas no notable imAEs in JX-594 plus anti-PD1 group. JX-594 plus anti-PD1 induced changes in TIME of both early- and advanced-stage mRCC model. However, tumor-suppressing TIME was more notable in early-stage mRCC model, which increased tumor-infiltrating CD8+ T cells and tumor-suppressing M1 tumor-associated macrophages (TAM), and decreased tumor-promoting myeloid-derived suppressor cells (MDSCs) and M2 TAM. Conclusions: JX-594 plus anti-PD1 effectively reduced primary tumors and metastatic burdens similar to ICI combination therapy. Furthermore, imAEs significantly decreased in JX-594 plus anti-PD1 group, suggesting the potential benefit of JX-594 plus anti-PD1 for reserving ICI induced toxicities, especially by anti-CTLA-4.

Gene Expression Analysis of Aggressive Adult Xp11.2 Translocation Renal Cell Carcinoma at Clinical Stage T1N0M0 to Identify Potential Prognostic and Therapeutic Biomarkers

Xp11.2 translocation renal cell carcinoma (tRCC), involving transcription factor E3 (TFE3) gene fusions, is a rare and aggressive RCC variant when present in adults and has been recently recognized as a unique entity in RCC. Biomarkers and treatment guidelines do not exist for patients with aggressive Xp11.2 tRCC. The aim was to identify and evaluate therapeutic biomarkers for aggressive Xp11.2 tRCC. RNA sequencing was performed using formalin-fixed, paraffin-embedded tissues from 11 adult patients with clinical T1N0M0 Xp11.2 tRCC, including three patients with aggressive characteristics (recurrence or cancer-specific death after nephrectomy). Thirty genes were differentially expressed between the aggressive and non-aggressive groups, even after adjustment, and were associated with KEGG pathways related to the aggressiveness of Xp11.2 tRCC. PIK3R2, involved in various KEGG pathways, including the PI3K/AKT/mTOR pathway, was overexpressed in the Xp11.2 tRCC cell lines UOK120 and UOK146. The PI3K pathway inhibitor LY294002 showed a significant therapeutic benefit. This study provides the first candidate biomarker, PIK3R2, for aggressive clinical T1N0M0 Xp11.2 tRCC. Furthermore, this study is the first to recommend a targeted drug, LY294002, for aggressive Xp11.2 tRCC based on the molecular pathophysiology.

Systemic Injection of Oncolytic Vaccinia Virus Suppresses Primary Tumor Growth and Lung Metastasis in Metastatic Renal Cell Carcinoma by Remodeling Tumor Microenvironment

Immune checkpoint inhibitors and tyrosine kinase inhibitors are the first-line treatment for metastatic renal cell carcinoma (mRCC), but their benefits are limited to specific patient subsets. Here, we aimed to evaluate the therapeutic efficacy of JX-594 (pexastimogene devacirepvec, Pexa-vec) monotherapy by systemic injection in comparison with sunitinib monotherapy in metastatic orthotopic RCC murine models. Two highly metastatic orthotopic RCC models were developed to compare the treatment efficacy in the International Metastatic RCC Database Consortium favorable-risk and intermediate- or poor-risk groups. JX-594 was systemically injected through the peritoneum, whereas sunitinib was orally administered. Post-treatment, tumor microenvironment (TME) remodeling was determined using immunofluorescence analysis. Systemic JX-594 monotherapy injection demonstrated therapeutic benefit in both early- and advanced-stage mRCC models. Sunitinib monotherapy significantly reduced the primary tumor burden and number of lung metastases in the early-stage, but not in the advanced-stage mRCC model. Systemic JX-594 delivery remodeled the primary TME and lung metastatic sites by increasing tumor-infiltrating CD4/8+ T cells and dendritic cells. Systemic JX-594 monotherapy demonstrated significantly better therapeutic outcomes compared with sunitinib monotherapy in both early- and advanced-stage mRCCs by converting cold tumors into hot tumors. Sunitinib monotherapy effectively suppressed primary tumor growth and lung metastasis in early-stage mRCC.

The DEAD/DEAH Box Helicase, DDX11, Is Essential for the Survival of Advanced Clear Cell Renal Cell Carcinoma and Is a Determinant of PARP Inhibitor Sensitivity

Simple Summary

DDX11, a helicase involved in sister chromatid cohesion, was identified as a significant biomarker of aggressive renal cell carcinoma (RCC) in our previous studies. In this study, we evaluated the molecular pathways through which DDX11 is involved in RCC cell survival. Furthermore, we assessed the sensitivity of poly (ADP-ribose) polymerase (PARP) inhibitors, which have not been used in RCC treatment, in association with DDX11 expression. DDX11-deficient RCC inhibited RCC proliferation, caused defects in segregation, and increased apoptosis. DDX11-deficient RCC was associated with increased sensitivity to PARP inhibition. DDX11 could be a novel therapeutic and prognostic biomarker for RCC patients, and this study is the first to suggest the use of PARP inhibitors in DDX11-deficient RCC patients.

Abstract

Genes associated with the DEAD-box helicase DDX11 are significant biomarkers of aggressive renal cell carcinoma (RCC), but their molecular function is poorly understood. We analyzed the molecular pathways through which DDX11 is involved in RCC cell survival and poly (ADP-ribose) polymerase (PARP) inhibitor sensitivity. Immunohistochemistry and immunoblotting determined DDX11 expression in normal kidney tissues, benign renal tumors, and RCC tissues and cell lines. Quantitative polymerase chain reaction validated the downregulation of DDX11 in response to transfection with DDX11-specific small interfering RNA. Proliferation analysis and apoptosis assays were performed to determine the impact of DDX11 knockdown on RCC cells, and the relevant effects of sunitinib, olaparib, and sunitinib plus olaparib were evaluated. DDX11 was upregulated in high-grade, advanced RCC compared to low-grade, localized RCC, and DDX11 was not expressed in normal kidney tissues or benign renal tumors. DDX11 knockdown resulted in the inhibition of RCC cell proliferation, segregation defects, and rapid apoptosis. DDX11-deficient RCC cells exhibited significantly increased sensitivity to olaparib compared to sunitinib alone or sunitinib plus olaparib combination treatments. Moreover, DDX11 could determine PARP inhibitor sensitivity in RCC. DDX11 could serve as a novel therapeutic biomarker for RCC patients who are refractory to conventional targeted therapies and immunotherapies.

Development of a highly pulmonary metastatic orthotopic renal cell carcinoma murine model

The incidence of renal cell carcinoma (RCC) is high, and its outcomes remain poor. Mortality is attributable largely to metastatic disease and a dearth of effective therapeutic interventions. The lungs are the most common metastatic site. To elucidate the biological mechanisms underlying pulmonary metastasis and identify superior therapeutic strategies, we developed a novel and clinically relevant murine RCC model exhibiting enhanced pulmonary metastasis. Mice underwent intrarenal implantation using luciferase-expressing Renca, a murine renal adenocarcinoma cell line. Primary renal tumor progression and development of metastatic lung lesions were monitored in live mice using bioluminescent imaging, followed by post-mortem organ assessment. Cells were isolated from pulmonary metastases for reimplantation, followed by repeat monitoring and assessment. This process was repeated once more for a total of two in vivo passages to select for pulmonary metastatic Renca cell subpopulations. However, a single round of in vivo selection was sufficient to produce a near-maximally metastatic subpopulation. Relative to Renca cell-implanted mice, subpopulation-implanted mice exhibited shorter implantation-metastasis intervals (5 days), shorter implantation-moribundity intervals (sacrificed at 18.6±2.9 versus 22.3±1.1 days), a higher number of metastatic lung lesions at 23 days (183.9±39.0 versus 172.6±38.2) and poorer survival. Implantation of cells derived from the second round of in vivo selection produced no further significant differences in the above metrics. This model consistently and efficiently recapitulates RCC pulmonary metastasis while allowing in vivo monitoring of tumor progression, thereby facilitating elucidation of the molecular mechanisms underlying pulmonary metastasis and evaluation of therapeutic modalities.

AXIN2 and SNAIL expression predict the risk of recurrence in cutaneous squamous cell carcinoma after Mohs micrographic surgery

Recurrence is a common complication observed during cutaneous squamous cell carcinoma (cSCC) treatment; however, biomarkers for predicting recurrence in cSCC remain unknown. The present study aimed to investigate the predictive value of axis inhibition protein 2 (AXIN2) and SNAIL expression in cSCC recurrence. AXIN2 and SNAIL expression was evaluated using immunohistochemistry in 111 cSCC tissue samples obtained from 18 patients who presented recurrence (recurrence interval, 1–91 months) and 93 patients who did not experience recurrence following Mohs micrographic surgery (MMS) during the follow-up period (156 months). Nomogram construction was performed using patients' clinicopathological characteristics and AXIN2 and SNAIL protein expression. The results demonstrated that high AXIN2 (histoscore >100) and SNAIL (histoscore >100) expression was detected in 35 and 44 cSCC tissues, respectively. Furthermore, the expression levels of AXIN2 and SNAIL were significantly associated in patients with cSCC (P=0.001). AXIN2 and SNAIL expression levels were significantly associated with tumor size (P=0.021 and P=0.044, respectively) and recurrence of cSCC (P=0.017 and P=0.042, respectively). In addition, the results of the Kaplan-Meier curve analysis revealed that recurrence-free survival was significantly associated with tumor size (P=0.025), differentiation status (P<0.001), AXIN2 expression (P=0.001) and SNAIL expression (P=0.001). Furthermore, the results of the multivariate analysis demonstrated that age (P=0.043), AXIN2 expression (P=0.001) and SNAIL expression (P=0.045) were independent risk factors for cSCC recurrence in the present cohort. A nomogram for predicting the 1-, 2-, 3-, and 5-year recurrence-free survival was developed for patients with cSCC by including independent risk factors with a concordance index of 0.75. The results suggested that high AXIN2 and SNAIL expression may be considered as potential risk factors for cSCC recurrence. This nomogram may therefore be useful to assess the probability of recurrence in patients with cSCC following MMS.

Comparison of microscopic and molecular enumeration methods for insect viruses: Cryptophlebia leucotreta granulovirus as a case study

Enumeration techniques were compared for quantification of the South African isolate of Cryptophlebia leucotreta granulovirus (CrleGV-SA), used as a biopesticide to control false codling moth (Thaumatotibia leucotreta), an insect pest of various fruits and nuts, including citrus. The routine enumeration method for CrleGV-SA virus particles in experimentation and production of CrleGV-SA biopesticides is dark field microscopy. This method was compared with spectrophotometry, scanning electron microscopy (SEM) and real time quantitative polymerase chain reaction (qPCR). The purpose was to develop an accurate and reliable routine enumeration method for CrleGV-SA occlusion bodies (OBs) and to validate the use of dark field microscopy. Purified and semi-purified CrleGV-SA viral stocks were used. Spectrophotometry was not a suitable or accurate enumeration method. Dark field microscopy and SEM were accurate and statistically comparable (p = 0.064), validating the use of dark field microscopy as an enumeration method for granulovirus (GV). However, SEM has superior resolution and the advantage of easily distinguishing virus particles from debris in semi-purified viral stock preparations. A quantitative PCR technique has been developed based on use of specific oligonucleotide primers for the granulin gene. This has the advantage of not being affected by contamination with non-biological debris or biological material, which impact on the other methods.

Nanoconfinement effects of chemically reduced graphene oxide nanoribbons on poly(vinyl chloride)

Polymeric nanocomposites with graphene-based nanocarbons (GNCs) have been extensively studied with emphasis on the percolation of nanofillers toward electrical, rheological, and mechanical reinforcement. In this study, we report an unusual indirect reinforcing phenomenon of highly defective GNCs dispersed in the poly(vinyl chloride) (PVC) matrix via densification of the polymer packing originating from nanoscale confinement. Herein, chemically reduced graphene oxide nanoribbons (C-rGONRs) are employed as a nanofiller. The inclusion of defective and oxygen-functionalized C-rGONRs resulted in a dramatic densification of the PVC host with extremely low C-rGONR loading, largely exceeding the theoretical calculation from a rule of mixture. Along with the densification, the glass transition temperature of PVC also increased by 28.6 °C at 0.1 wt% filler loading. Remarkably, the oxygen barrier property and mechanical toughness under tension for the PVC/C-rGONR nanocomposite were the maximum when the greatest densification occurred. The structure-property relationship of the nanocomposites has been discussed with an emphasis on the nanoscale confinement phenomenon.

Interpretation of digital breast tomosynthesis: preliminary study on comparison with picture archiving and communication system (PACS) and dedicated workstation

OBJECTIVE

To compare the diagnostic accuracy and efficiency in the interpretation of digital breast tomosynthesis (DBT) images using a picture archiving and communication system (PACS) and a dedicated workstation.

METHODS

97 DBT images obtained for screening or diagnostic purposes were stored in both a workstation and a PACS and evaluated in combination with digital mammography by three independent radiologists retrospectively. Breast Imaging-Reporting and Data System final assessments and likelihood of malignancy (%) were assigned and the interpretation time when using the workstation and PACS was recorded. Receiver operating characteristic curve analysis, sensitivities and specificities were compared with histopathological examination and follow-up data as a reference standard.

RESULTS

Area under the receiver operating characteristic curve values for cancer detection (0.839 vs 0.815, p = 0.6375) and sensitivity (81.8% vs 75.8%, p = 0.2188) showed no statistically significant differences between the workstation and PACS. However, specificity was significantly higher when analysing on the workstation than when using PACS (83.7% vs 76.9%, p = 0.009). When evaluating DBT images using PACS, only one case was deemed necessary to be reanalysed using the workstation. The mean time to interpret DBT images on PACS (1.68 min/case) was significantly longer than that to interpret on the workstation (1.35 min/case) (p < 0.0001).

CONCLUSION

Interpretation of DBT images using PACS showed comparable diagnostic performance to a dedicated workstation, even though it required a longer reading time. Advances in knowledge: Interpretation of DBT images using PACS is an alternative to evaluate the images when a dedicated workstation is not available.

Dovitinib (TKI258), a multi-target angiokinase inhibitor, is effective regardless of KRAS or BRAF mutation status in colorectal cancer

INTRODUCTION

We aimed to determine whether KRAS and BRAF mutant colorectal cancer (CRC) cells exhibit distinct sensitivities to the multi-target angiokinase inhibitor, TKI258 (dovitinib).

MATERIALS AND METHODS

We screened 10 CRC cell lines by using receptor tyrosine kinase (RTK) array to identify activated RTKs. MTT assays, anchorage-independent colony-formation assays, and immunoblotting assays were performed to evaluate the in vitro anti-tumor effects of TKI258. In vivo efficacy study followed by pharmacodynamic evaluation was done.

RESULTS

Fibroblast Growth Factor Receptor 1 (FGFR1) and FGFR3 were among the most highly activated RTKs in CRC cell lines. In in vitro assays, the BRAF mutant HT-29 cells were more resistant to the TKI258 than the KRAS mutant LoVo cells. However, in xenograft assays, TKI258 equally delayed the growth of tumors induced by both cell lines. TUNEL assays showed that the apoptotic index was unchanged following TKI258 treatment, but staining for Ki-67 and CD31 was substantially reduced in both xenografts, implying an anti-angiogenic effect of the drug. TKI258 treatment was effective in delaying CRC tumor growth in vivo regardless of the KRAS and BRAF mutation status.

CONCLUSIONS

Our results identify FGFRs as potential targets in CRC treatment and suggest that combined targeting of multiple RTKs with TKI258 might serve as a novel approach to improve outcome of patients with CRC.

Using genetic profiles of African forest elephants to infer population structure, movements, and habitat use in a conservation and development landscape in Gabon

Conservation of wide-ranging species, such as the African forest elephant (Loxodonta cyclotis), depends on fully protected areas and multiple-use areas (MUA) that provide habitat connectivity. In the Gamba Complex of Protected Areas in Gabon, which includes 2 national parks separated by a MUA containing energy and forestry concessions, we studied forest elephants to evaluate the importance of the MUA to wide-ranging species. We extracted DNA from elephant dung samples and used genetic information to identify over 500 individuals in the MUA and the parks. We then examined patterns of nuclear microsatellites and mitochondrial control-region sequences to infer population structure, movement patterns, and habitat use by age and sex. Population structure was weak but significant, and differentiation was more pronounced during the wet season. Within the MUA, males were more strongly associated with open habitats, such as wetlands and savannas, than females during the dry season. Many of the movements detected within and between seasons involved the wetlands and bordering lagoons. Our results suggest that the MUA provides year-round habitat for some elephants and additional habitat for others whose primary range is in the parks. With the continuing loss of roadless wilderness areas in Central Africa, well-managed MUAs will likely be important to the conservation of wide-ranging species.

Abstract B196: FGFR3 as a potential target for gastric cancer

While trastuzumab against HER-2 over-expression is the only approved targeted therapy against gastric cancer, it is important to find the biologically significant genetic aberrations in most of gastric cancer without HER-2 overexpression. We performed phospho-RTK (receptor tyrosine kinase) array in 25 gastric cancer cell lines, and confirmed fibroblast growth factor receptor 2 and 3 (FGFR2, 3) as one of the highly phosphorylated RTKs. Knockdown of FGFR3 with transfecting small interfering RNA (siRNA) induced the decrement of phospho-FGFR (653/654) in a time-dependent manner in cell lines with highly activated FGFR3, Hs746T and SNU-5. While cell cycle analysis and apoptosis assay showed no significant changes, invasiveness and anchorage-independent growth was inhibited after FGFR3 siRNA transfection. Modulation of downstream signaling molecules was observed by western blot after transfecting FGFR3 siRNA in Hs746T and SNU-5 cell lines in comparing with FGFR2 activated cell lines (KATO III, SNU-16) transfected with FGFR2 siRNA, since previous reports showed that FGFR2 amplification is important in gastric cancer in influencing cell proliferation and survival. Phospho-AKT was down-regulated in both FGFR2 and FGFR3 activated cell lines after specific siRNA transfection, implying that gastric cancer cells with FGFR2 or FGFR3 activation might be both dependent on PI3K-AKT-mTOR pathway. When we treated mice bearing subcutaneous SNU-5 tumor xenografts with oral FGFR inhibitor TKI-258 (70mg/kg daily), TKI-258 treated group showed anti-tumor growth and anti-angiogenic effect compared with control group. Immunohistochemistry (IHC) against FGFR3 among 116 N3 gastric cancer patient tissues showed 3+ in 62.9%, while FGFR2 positivity was only 11.2%. In summary, we identified FGFR3 harbors significant biological role in subset of gastric cancer patients as FGFR2. Further studies for validating the efficacy of FGFR inhibition in preselected subset of patients would support the proper development of FGFR inhibitor in gastric cancer.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B196.

Citation Format: Choong-kun Lee, Won Suk Lee, Jeong Min Kim, Myung Eun Lee, Kyu Hyun Park, Tae Soo Kim, Hyo Song Kim, Hei-Cheul Jeung, Hyun Cheol Chung, Sun Young Rha. FGFR3 as a potential target for gastric cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B196.

Extent and ecological consequences of hunting in Central African rainforests in the twenty-first century

Humans have hunted wildlife in Central Africa for millennia. Today, however, many species are being rapidly extirpated and sanctuaries for wildlife are dwindling. Almost all Central Africa's forests are now accessible to hunters. Drastic declines of large mammals have been caused in the past 20 years by the commercial trade for meat or ivory. We review a growing body of empirical data which shows that trophic webs are significantly disrupted in the region, with knock-on effects for other ecological functions, including seed dispersal and forest regeneration. Plausible scenarios for land-use change indicate that increasing extraction pressure on Central African forests is likely to usher in new worker populations and to intensify the hunting impacts and trophic cascade disruption already in progress, unless serious efforts are made for hunting regulation. The profound ecological changes initiated by hunting will not mitigate and may even exacerbate the predicted effects of climate change for the region. We hypothesize that, in the near future, the trophic changes brought about by hunting will have a larger and more rapid impact on Central African rainforest structure and function than the direct impacts of climate change on the vegetation. Immediate hunting regulation is vital for the survival of the Central African rainforest ecosystem.

Discovery and characterization of a novel 7-aminopyrazolo[1,5-a]pyrimidine analog as a potent hepatitis C virus inhibitor

We describe a novel 7-aminopyrazolo[1,5-a]pyrimidine (7-APP) derivative as a potent hepatitis C virus (HCV) inhibitor. A series of 7-APPs was synthesized and evaluated for inhibitory activity against HCV in different cell culture systems. The synthesis and preliminary structure-activity relationship study of 7-APP are reported.

Abstract 3414: Role of FGFR2 in invasion and metastasis through different activation of downstream signaling in gastric cancer

Activation of fibroblast growth factor receptors (FGFRs), the family of receptor tyrosine kinase (RTK), initiates intracellular signaling networks for key cellular processes. Previous reports show that FGFR2 amplification induces activation of downstream signaling in gastric cancer influencing cell proliferation and survival. In this study, we evaluated activation of FGFRs and related downstream pathways, and also determine the effect of FGFRs in tumor invasion and metastasis in gastric cancer. First, we performed phospho-RTK array in 25 gastric cancer cell lines and found that FGFR2 and FGFR3 were more frequently phosphorylated than FGFR1 or FGFR4 in gastric cancer. Next, we observed genomic amplification status and phosphorylation level of FGFR2 using real-time PCR and Western blot. KATO III and SNU-16 with higher expression of FGFR2 showed high correlation between DNA amplification and phosphorylation status. Then, using invasion assay, cells with higher FGFR3 showed higher invasiveness compare to cells with FGFR2 overexpression. When we observed the activation status of downstream signaling molecules, cells with higher FGFR2 were more dependent on PI3K-AKT-mTOR pathway, while cells with higher FGFR3 were more dependent on ERK pathway. In conclusion, FGFRs have various biological roles through different signaling pathways in gastric cancer, suggesting that FGFRs are the potential molecular targets in gastric cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3414. doi:1538-7445.AM2012-3414

Abstract 2426: Role of fibroblast growth factor receptor 1 (FGFR1) in liver metastasis of colorectal cancer

Liver metastasis is one of the main cause of death among patients with colorectal cancer (CRC). However, accurate prediction of liver metastasis of CRC is difficult at the inception of diagnosis. Activated receptor tyrosine kinases (RTKs) are the main mediators of the signaling pathway related to cell survival, proliferation, differentiation or apoptosis. To determine if any of these RTKs are involved in liver metastasis from CRC, we performed phospho-receptor tyrosine kinase array with matched 20 colon normal mucosa, primary tumor, metastatic liver tumor, and liver normal tissue proteins using Human Phospho-RTK Array (2009 AACR, #4951). In RTK activation profiling, FGFR1 activation was increased in a high proportion of metastatic liver tumor (p &lt; 0.05). To evaluate the functional roles of FGFR1, DLD-1 and LoVo colon cancer cells were treated with FGFR1 specific siRNA or RTK inhibitor. Inhibition of FGFR1 inhibited phosphorylation of PI3K/AKT and ERK, a downstream cellular signaling molecule of FGFR; whereas, mTOR, p70S6K, JNK and Src activities were not affected. Also, we compared the cell migration and invasion ability by wound healing assay and invasion assay. The invasion capacity and wound closing were significantly delayed by FGFR1 inhibition (p &lt;0.05). To evaluate in vivo anti-metastatic effect of FGFR1, we used an orthotropic liver metastasis model, generated by injecting LoVo colon cancer cells into spleen of BALB/c nu/nu mice. In control group, multiple large metastatic foci were evident, whereas the extent of liver metastasis was dramatically reduced in TKI-258 (50mg/kg/d) treated group (48.9%, p&lt;0.05). Immunoexpression of the p-FGFR1 was much more intense in control than TKI-258 treated tumor tissues. Biological effects were also confirmed that FGFR1 inhibition resulted in a significant reduction of ERK activation and Ki-67 positive cells in tumor tissues. In conclusion, FGFR1 might be a good target for liver metastasis of CRC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2426. doi:1538-7445.AM2012-2426

Abstract C157: Identification of activated receptor tyrosine kinases in colon cancer cell lines

Colorectal cancer (CRC) is the second most common cause of cancer-related death in the United States and increasing rapidly in Asian countries. To improve colorectal cancer treatment, relevant molecular targets need to be identified. Receptor tyrosine kinases (RTKs) are multifunctional transmembrane proteins and important mediators of the signaling cascade, determining key roles in diverse biological processes such as proliferation, growth, differentiation, and apoptosis of cells. Recent advances in understanding of cellular signaling by RTKs have brought to light the potential of RTKs as anti-cancer targets. To determine if any of these RTKs are activated in colorectal cancer, we performed phospho-receptor tyrosine kinase array and evaluated its possibility as a therapeutic target. We examined activation pattern of RTKs in 10 colon cancer cell lines using Human Phospho-RTK Antibody Proteome Profiler Array (R&D Systems). Relative levels of tyrosine phosphorylation of RTKs among these cell lines were determined as a ratio relative to positive control's intensity in each membrane. TKI-258 (Novartis Inc.), a specific class III-V RTK inhibitor, was used to evaluate its anti-cancer effect. To confirm of anti-cancer effect of TKI-258 in vivo, xenograft model with LoVo cells was used. We found that various RTKs including fibroblast growth factor receptor (FGFR), vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR) were highly activated in colon cancer cell lines. The RTK activity and related signaling molecules were decreased on TKI-258 treatment in a time-dependent manner. Also, TKI-258 treated cells showed significantly impaired anchorage-independent growth in soft agar colony formation assay as compared with the control cells. In vivo xenograft model, TKI-258 treated group showed anti-tumor growth effect compared with control group. These results suggested that various RTKs are highly activated in colorectal cancer, and these RTKs might be specific targets for colorectal cancer treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C157.

Abstract 3957: Identification of activated receptor tyrosine kinases in gastric cancer cells

To improve gastric cancer treatment, relevant molecular targets need to be identified. Receptor tyrosine kinases (RTKs) are multifunctional transmembrane proteins and important mediators of the signaling cascade, determining key roles in diverse biological processes like proliferation, growth, differentiation, and apoptosis of cancer cells. To determine if any of these RTKs are activated in gastric cancer, we performed phospho-receptor tyrosine kinase array with 25 gastric cancer cell lines using Human Phospho-RTK Antibody Proteome Profiler Array (R&D Systems) which includes 42 different tyrosine kinases. Relative levels of tyrosine phosphorylation of RTKs among these cell lines were determined as a ratio relative to four positive phosphorylated tyrosine kinase control's intensity in each membrane.

We found that various growth factor receptor tyrosine kinases were differentially activated and 15 of 42 RTKs were highly activated with mean intensity &gt;5 among 25 gastric cancer cell lines. The highly activated RTKs were: EGFR (93.2), ErbB2 (33.0), HGFR (27.6), ErbB3 (26.2), IGF-IR (17.2), InsulinR (13.9), Mer (12.9), FGFR2α (11.4), Dtk (10.1), EphA7 (9.5), Tie-2 (8.9), MSPR (6.5), c-Ret (6.4), FGFR3 (5.4), and ErbB4 (5.1). These receptors basically belong to the EGF, HGF, FGF, Insulin, Tie, and Ephrin growth factor gene families_all of which are involved in cell proliferation, differentiation or signal transduction. We confirmed that increased RTKs phosphorylation observed by RTK array analysis was correlated with the expression level of each protein by immunoblotting. Additionally, we showed that Met gene amplification by quantitative real-time PCR is associated with Met activation in gastric cancer cell lines. In conclusion, these activated RTKs may work as potential therapeutic targets in gastric cancer and helpful to understand the molecular mechanisms underlying tumor development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3957.

Mannose-binding lectin is present in human semen and modulates cellular adhesion of Neisseria gonorrhoeae in vitro

Mannose-binding lectin (MBL) is an innate immune molecule present in blood and some mucosal tissues, which can influence microbial attachment and inflammatory responses of host cells during infection. In this study MBL was found to be present at a low concentration in semen samples in the range 1.2-24.9 ng/ml. Co-incubation of bacteria with semen resulted in the binding of MBL to the bacterial surface. Neisseria gonorrhoeae is a common cause of genitourinary infection. MBL bound to N. gonorrhoeae with strain-to-strain variation in the intensity of binding and nature of the bacterial receptor. Pretreatment with MBL concentrations similar to those found in human serum modulated the adhesion of N. gonorrhoeae strain FA1090 but not strain MS11 to epithelial cells. This effect was dose-dependent. This work demonstrates that MBL is present in human semen and modifies cellular responses to N. gonorrhoeae in a concentration-dependent manner.

Subtelomeric DNA methylation and telomere length in human cancer cells

Subtelomeric epigenetic modifications are known to be associated with telomere length. We examined subtelomeric DNA methylation at seven sites for five chromosomes by methylation-specific PCR (MSP) and two sites for two chromosomes by bisulfite genomic sequencing (BGS) in 20 human cancer cell lines and subsequently analyzed their association with telomere length. Full-methylation (55/140) was more frequently found compared to un-methylation (35/140) (p=0.01). Subtelomeric-methylation patterns varied from region to region; full-methylation and un-methylation were dominant at one of 9q sites (20/20) and 9p (18/20), respectively. MSP and BGS data exhibited no apparent correlation between methylation status and telomere length. In addition, Hep3B subclones that possessed different telomere lengths exhibited no changes in methylation status according to telomeres. In summary, subtelomeres might form distinct chromatin structures from region to region and effect of subtelomeric DNA methylation on telomere regulation might be little.

Phase II trial of irinotecan/gemcitabine as second-line therapy for relapsed and refractory small-cell lung cancer: Cancer and Leukemia Group B Study 39902

BACKGROUND

This phase II study evaluated the efficacy and safety of the irinotecan/gemcitabine combination in patients with relapsed/refractory small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Patients with measurable tumor who had received one previous chemotherapy or chemotherapy/radiation regimen were eligible. Gemcitabine 1000 mg/m(2) was administered i.v. over 30 min followed immediately by irinotecan 100 mg/m(2) i.v. over 90 min, both on days 1 and 8 every 21 days. Patients were stratified based on response to initial treatment [i.e. primary sensitive disease with progression >or=3 months (group A), or refractory disease (group B)].

RESULTS

Seventy-three patients were enrolled but one never received treatment and one ineligible patient did not have SCLC. Median patient ages of the remaining patients were 61 and 63 years in groups A (n = 35) and B (n = 36), respectively, with performance status of 0 or 1 in 85% of 71 patients. Primary grade 3/4 toxic effects in groups A versus B were neutropenia (36% versus 43%), thrombocytopenia (36% versus 26%), nausea (12% versus 11%), vomiting (0 versus 11%), diarrhea (12% versus 9%), and pulmonary (12% versus 12%). Two patients had fatal events including pneumonitis (n = 1) and acute respiratory distress syndrome (n = 1). Responses occurred in 11 group A [two complete responses and nine partial responses (PRs)] and four group B (all PRs) patients, for response rates of 31% [95% confidence interval (CI) 17%, 49%) and 11% (95% CI 3%, 26%), respectively. Median survival and progression-free survival times were 7.1 (95% CI 6, 10.5) versus 3.5 (95% CI 3.1, 5.7) months, and 3.1 (95% CI 1.6, 5.3) versus 1.6 (95% CI 1.4, 2.8) months for group A versus B.

CONCLUSION

The irinotecan/gemcitabine combination is active and well tolerated as second-line therapy in SCLC patients. Additional studies are warranted as second-line therapy in patients who progressed 90 days or more after first-line therapy. However, the observed efficacy results in refractory SCLC patients indicate that this regimen should not be further explored in this population.

Haplotype-specific gene expression profiles in a telomeric major histocompatibility complex gene cluster and susceptibility to autoimmune diseases

The telomeric class III region of the major histocompatibility complex is gene dense, but apart from the three tumour necrosis factor (TNF) superfamily members (TNF, lymphotoxin alpha and lymphotoxin beta) little is known of the expression and function of the majority of the genes. Recent genetic studies in autoimmune diseases, particularly rheumatoid arthritis (RA), have suggested a human leukocyte antigen (HLA)-DR-independent disease effect in this region. To gain further insights into these associations, we used lipopolysaccharide-stimulated human macrophages to examine inducible mRNA expression and genotype-phenotype relationships for genes in this region. Following stimulation in addition to the expected induction of TNF mRNA, a 14-fold increase of ATP6V1G2 at 18 h (P<0.001) was seen, whereas B-associated transcript (BAT)2 (P<0.001) and leucocyte-specific transcript (LST)1 (P<0.001) were both downregulated. By genotyping single-nucleotide polymorphisms spanning a 70 kb interval centred on the TNF locus, we constructed haplotypes and determined associated expression profiles for 10 genes in the cluster using quantitative real-time polymerase chain reaction. Overexpression of BAT1 mRNA was associated with carriers of a haplotype containing the LST1 marker transmitted to RA cases in a family study and also DRB1(*)15 associated with susceptibility to nephritis in systemic lupus erythematosus. The implications of our findings for the understanding of genetic associations with disease susceptibility in this region are discussed.

Molecular mechanisms of morning onset of myocardial infarction

We recently isolated a novel bHLH/PAS protein, CLIF (cycle like factor), by yeast two-hybrid screening of human umbilical endothelial cell cDNA library. CLIF is preferentially expressed in endothelial and neuronal cells. Because CLIF is expressed in vascular endothelial cells and forms a heterodimer with CLOCK, the key transcription factor controlling the circadian rhythm, we hypothesized that CLIF regulates the circadian oscillation of PAI-1 gene expression in endothelial cells. Northern blot analysis of mouse organs showed circadian oscillations of PAI-I mRNA levels. In addition, the clock-related genes also showed circadian oscillation in peripheral tissues. In endothelial cells, the heterodimer of CLIF and CLOCK upregulated the PAI-1 gene expression through E-box sites. Furthermore, Period and Cryptochrome, which are negative regulators in the feedback loop of the biological clock, inhibited PAI-1 promoter activation by the CLOCK:CLIF heterodimer. These results suggest that the peripheral tissues have their own biological clock and CLIF regulates the circadian oscillation of PAI-1 gene expression in endothelial cells. This study suggests a novel molecular mechanism of the morning onset of myocardial infarction. Here we review our recent work and literature.

Role of macrophage-expressed adipocyte fatty acid binding protein in the development of accelerated atherosclerosis in hypercholesterolemic mice

Atherosclerosis is an inflammatory disease process associated with elevated levels of plasma cholesterol, especially low-density lipoproteins. The latter become trapped within the arterial wall and are oxidized and taken up by macrophages to form foam cells. This process is an initiating event for atherosclerosis. Fatty acid binding proteins (FABP) are involved in fatty acid metabolism and cellular lipid transport, and adipocyte FABP (aP2) is also expressed in macrophages. We recently generated mice lacking both apolipoprotein (Apo)E and aP2 (ApoE-/-aP2-/-) and found that these mice, compared with ApoE-/- mice, developed markedly smaller atherosclerotic lesions that contained fewer macrophages. Here we investigated the mechanism(s) responsible for this prevention of atherosclerotic lesion formation. Bone marrow transplantations were performed in ApoE-/- mice, receiving cells from either ApoE-/- or ApoE-/-aP2-/- mice. The lack of aP2 in donor marrow cells led to the development of smaller (5.5-fold) atherosclerotic lesions in the recipient mice. No differences were found in plasma cholesterol, glucose, or insulin levels between recipients of bone marrow cells from ApoE-/- or ApoE-/-aP2-/- mice. However, the expression of chemoattractant and inflammatory cytokines was decreased in macrophages from ApoE-/-aP2-/- mice compared with ApoE-/- mice, which may contribute to the decrease in atherosclerotic lesion formation. Taken together, we demonstrate the importance of macrophage aP2 in the development of atherosclerotic lesions.

Impaired abdominal wall development and deficient wound healing in mice lacking aortic carboxypeptidase-like protein

Aortic carboxypeptidase-like protein (ACLP) is a member of a diverse group of proteins that contain a domain with similarity to that of the Dictyostelium discoideum protein discoidin I. The discoidin domain has been identified in mammalian milk fat globule membrane proteins, blood coagulation factors, and receptor tyrosine kinases, where it may facilitate cell aggregation, adhesion, or cell-cell recognition. Here we show that ACLP is a secreted protein that associates with the extracellular matrix (ECM). During mouse embryogenesis, ACLP is abundantly expressed in the ECM of collagen-rich tissues, including the vasculature, dermis, and the developing skeleton. We deleted the ACLP gene in mice by homologous recombination. The majority of ACLP(-/-) mice die perinatally due to gastroschisis, a severe disruption of the anterior abdominal wall and herniation of the abdominal organs. ACLP(-/-) mice that survived to adulthood developed nonhealing skin wounds. Following injury by a dermal punch biopsy, ACLP(-/-) mice exhibited deficient wound healing compared with controls. In addition, dermal fibroblasts isolated from ACLP(-/-) 18.5-day-postconception embryos exhibited a reduced proliferative capacity compared with wild-type cells. These results indicate that ACLP is an ECM protein that is essential for embryonic development and dermal wound healing processes.

Cardiac-specific expression of heme oxygenase-1 protects against ischemia and reperfusion injury in transgenic mice

Heme oxygenase (HO)-1 degrades the pro-oxidant heme and generates carbon monoxide and antioxidant bilirubin. We have previously shown that in response to hypoxia, HO-1-null mice develop infarcts in the right ventricle of their hearts and that their cardiomyocytes are damaged by oxidative stress. To test whether HO-1 protects against oxidative injury in the heart, we generated cardiac-specific transgenic mice overexpressing different levels of HO-1. By use of a Langendorff preparation, hearts from transgenic mice showed improved recovery of contractile performance during reperfusion after ischemia in an HO-1 dose-dependent manner. In vivo, myocardial ischemia and reperfusion experiments showed that infarct size was only 14.7% of the area at risk in transgenic mice compared with 56.5% in wild-type mice. Hearts from these transgenic animals had reduced inflammatory cell infiltration and oxidative damage. Our data demonstrate that overexpression of HO-1 in the cardiomyocyte protects against ischemia and reperfusion injury, thus improving the recovery of cardiac function.

Exacerbation of chronic renovascular hypertension and acute renal failure in heme oxygenase-1-deficient mice

Heme oxygenase (HO) is a cytoprotective enzyme that degrades heme (a potent oxidant) to generate carbon monoxide (a vasodilatory gas that has anti-inflammatory properties), bilirubin (an antioxidant derived from biliverdin), and iron (sequestered by ferritin). Because of properties of HO and its products, we hypothesized that HO would be important for the regulation of blood pressure and ischemic injury. We studied chronic renovascular hypertension in mice deficient in the inducible isoform of HO (HO-1) using a one kidney-one clip (1K1C) model of disease. Systolic blood pressure was not different between wild-type (HO-1(+/+)), heterozygous (HO-1(+/-)), and homozygous null (HO-1(-/-)) mice at baseline. After 1K1C surgery, HO-1(+/+) mice developed hypertension (140+/-2 mm Hg) and cardiac hypertrophy (cardiac weight index of 5.0+/-0.2 mg/g) compared with sham-operated HO-1(+/+) mice (108+/-5 mm Hg and 4.1+/-0.1 mg/g, respectively). However, 1K1C produced more severe hypertension (164+/-2 mm Hg) and cardiac hypertrophy (6.9+/-0.6 mg/g) in HO-1(-/-) mice. HO-1(-/-) mice also experienced a high rate of death (56%) within 72 hours after 1K1C surgery compared with HO-1(+/+) (25%) and HO-1(+/-) (28%) mice. Assessment of renal function showed a significantly higher plasma creatinine in HO-1(-/-) mice compared with HO-1(+/-) mice. Histological analysis of kidneys from 1K1C HO-1(-/-) mice revealed extensive ischemic injury at the corticomedullary junction, whereas kidneys from sham HO-1(-/-) and 1K1C HO-1(+/-) mice appeared normal. Taken together, these data suggest that chronic deficiency of HO-1 does not alter basal blood pressure; however, in the 1K1C model an absence of HO-1 leads to more severe renovascular hypertension and cardiac hypertrophy. Moreover, renal artery clipping leads to an acute increase in ischemic damage and death in the absence of HO-1.

Heme oxygenase-1 protects against vascular constriction and proliferation

Heme oxygenase (HO-1, encoded by Hmox1) is an inducible protein activated in systemic inflammatory conditions by oxidant stress. Vascular injury is characterized by a local reparative process with inflammatory components, indicating a potential protective role for HO-1 in arterial wound repair. Here we report that HO-1 directly reduces vasoconstriction and inhibits cell proliferation during vascular injury. Expression of HO-1 in arteries stimulated vascular relaxation, mediated by guanylate cyclase and cGMP, independent of nitric oxide. The unexpected effects of HO-1 on vascular smooth muscle cell growth were mediated by cell-cycle arrest involving p21Cip1. HO-1 reduced the proliferative response to vascular injury in vivo; expression of HO-1 in pig arteries inhibited lesion formation and Hmox1-/- mice produced hyperplastic arteries compared with controls. Induction of the HO-1 pathway moderates the severity of vascular injury by at least two adaptive mechanisms independent of nitric oxide, and is a potential therapeutic target for diseases of the vasculature.

Regulation of myogenic terminal differentiation by the hairy-related transcription factor CHF2

We have recently cloned a novel basic helix-loop-helix factor, CHF2, that functions as a transcriptional repressor. To address its role in the regulation of myogenic terminal differentiation, we analyzed its expression pattern during C2C12 mouse myotube formation. In undifferentiated myoblasts, CHF2 is expressed at high levels. After induction of myotube formation in low serum, CHF2 expression is barely detectable at 3 days after induction. Myogenin expression, in contrast, peaks at 3 days. In transiently transfected 10T1/2 embryonic fibroblasts, CHF2 inhibited MyoD-dependent activation of the myogenin promoter in a dose-dependent fashion. Electrophoretic mobility shift analysis indicated that CHF2 inhibits the binding of the MyoD.E47 heterodimer to the E-box binding site. CHF2 also inhibited myogenic conversion of 10T1/2 cells by MyoD, as measured by skeletal myosin heavy chain protein expression. Coimmunoprecipitation analysis indicated that CHF2 forms a protein complex with MyoD. Mutational analysis of CHF2 indicated that the repression activity for both transcription and myogenic conversion mapped to a hydrophobic carboxyl-terminal region and did not require either the basic helix-loop-helix or YRPW motifs. Our data indicate that CHF2 functions as a transcriptional repressor of myogenesis by formation of an inactive heterodimeric complex with MyoD and likely plays an important role in muscle development.

Akt participation in the Wnt signaling pathway through Dishevelled

Inactivation of glycogen synthase kinase 3beta (GSK3beta) and the resulting stabilization of free beta-catenin are critical steps in the activation of Wnt target genes. While Akt regulates GSK3alpha/beta in the phosphatidylinositide 3-OH kinase signaling pathway, its role in Wnt signaling is unknown. Here we report that expression of Wnt or Dishevelled (Dvl) increased Akt activity. Activated Akt bound to the Axin-GSK3beta complex in the presence of Dvl, phosphorylated GSK3beta and increased free beta-catenin levels. Furthermore, in Wnt-overexpressing PC12 cells, dominant-negative Akt decreased free beta-catenin and derepressed nerve growth factor-induced differentiation. Therefore, Akt acts in association with Dvl as an important regulator of the Wnt signaling pathway.

Future C.E.O.'s in year 2002

Chief Executive Officers of mental health facilities have been interested civil leaders. Many doctors have accepted C.E.O. positions in our history. Today the competitions out to see who will be the future's C.E.O.'s. The rumors run from lawyers to clinicians from many of the hospital's disciplines and from purely administrative side of the hospitals management system. It will not be unusual to see more Ph.D., M.B.A.'s, or M.D., M.P.A. or M.S., M.H.A. degree combinations in year 2002.

Fibrin stimulates microfilament reorganization and IL-1beta production in human monocytic THP-1 cells

Fibrin plays important roles in the wound healing processes, including blood clotting and platelet aggregation. Additional activities of fibrin were found in this study, which utilizes human THP-1 cells treated 1,25-(OH)2 vitamin D3 and plasminolytic fragments derived from fibrin. Coated fibrin fragment E on culture plates induced cell adhesions and morphological changes of the THP-1 cells, being resembled to tissue macrophages. Morphological changes of the THP-1 cells were caused by microfilament reorganization. IL-1beta production was increased in the THP-1 cells by adherent fibrin fragment E, but not by fibrin fragment D or by fibrinogen fragment E. The elevation of IL-1beta production is caused by transcriptional activation. Incubation with cytochalacin D, an actin polymerization inhibitor, prevents both microfilament reorganization and morphological changes, but has no effect on the IL-1beta production stimulated by fibrin fragment E. This data suggests that the IL-1beta production in the THP-1 cells do not require microfilament reorganization and integrin aggregation. Taken together, these results indicate that fibrin matrix plays an additional role in the stimulation of monocytes for production of IL-1beta, morphological changes and cell adhesion, resulting in the facilitation of the wound healing processes.

Endotoxin-induced mortality is related to increased oxidative stress and end-organ dysfunction, not refractory hypotension, in heme oxygenase-1-deficient mice

BACKGROUND

Heme oxygenase (HO)-1 is an enzyme that degrades heme to generate CO (a vasodilatory gas), iron, and the potent antioxidant bilirubin. A disease process characterized by decreases in vascular tone and increases in oxidative stress is endotoxic shock. Moreover, HO-1 is markedly induced in multiple organs after the administration of endotoxin (lipopolysaccharide [LPS]) to mice.

METHODS AND RESULTS

To determine the role of HO-1 in endotoxemia, we administered LPS to mice that were wild-type (+/+), heterozygous (+/-), or homozygous null (-/-) for targeted disruption of HO-1. LPS produced a similar induction of HO-1 mRNA and protein in HO-1(+/+) and HO-1(+/-) mice, whereas HO-1(-/-) mice showed no HO-1 expression. Four hours after LPS, systolic blood pressure (SBP) decreased in all the groups. However, SBP was significantly higher in HO-1(-/-) mice (121+/-5 mm Hg) after 24 hours, compared with HO-1(+/+) (96+/-7 mm Hg) and HO-1(+/-) (89+/-13 mm Hg) mice. A sustained increase in endothelin-1 contributed to this SBP response. Even though SBP was higher, mortality was increased in HO-1(-/-) mice, and they exhibited hepatic and renal dysfunction that was not present in HO-1(+/+) and HO-1(+/-) mice. The end-organ damage and death in HO-1(-/-) mice was related to increased oxidative stress.

CONCLUSIONS

These data suggest that the increased mortality during endotoxemia in HO-1(-/-) mice is related to increased oxidative stress and end-organ (renal and hepatic) damage, not to refractory hypotension.

CLIF, a novel cycle-like factor, regulates the circadian oscillation of plasminogen activator inhibitor-1 gene expression

The onset of myocardial infarction occurs frequently in the early morning, and it may partly result from circadian variation of fibrinolytic activity. Plasminogen activator inhibitor-1 activity shows a circadian oscillation and may account for the morning onset of myocardial infarction. However, the molecular mechanisms regulating this circadian oscillation remain unknown. Recent evidence indicates that basic helix-loop-helix (bHLH)/PAS domain transcription factors play a crucial role in controlling the biological clock that controls circadian rhythm. We isolated a novel bHLH/PAS protein, cycle-like factor (CLIF) from human umbilical vein endothelial cells. CLIF shares high homology with Drosophila CYCLE, one of the essential transcriptional regulators of circadian rhythm. CLIF is expressed in endothelial cells and neurons in the brain, including the suprachiasmatic nucleus, the center of the circadian clock. In endothelial cells, CLIF forms a heterodimer with CLOCK and up-regulates the PAI-1 gene through E-box sites. Furthermore, Period2 and Cryptochrome1, whose expression show a circadian oscillation in peripheral tissues, inhibit the PAI-1 promoter activation by the CLOCK:CLIF heterodimer. These results suggest that CLIF regulates the circadian oscillation of PAI-1 gene expression in endothelial cells. In addition, the results potentially provide a molecular basis for the morning onset of myocardial infarction.

Striated muscle preferentially expressed genes alpha and beta are two serine/threonine protein kinases derived from the same gene as the aortic preferentially expressed gene-1

Aortic preferentially expressed gene (APEG)-1 is a 1.4-kilobase pair (kb) mRNA expressed in vascular smooth muscle cells and is down-regulated by vascular injury. An APEG-1 5'-end cDNA probe identified three additional isoforms. The 9-kb striated preferentially expressed gene (SPEG)alpha and the 11-kb SPEGbeta were found in skeletal muscle and heart. The 4-kb brain preferentially expressed gene was detected in the brain and aorta. We report here cloning of the 11-kb SPEGbeta cDNA. SPEGbeta encodes a 355-kDa protein that contains two serine/threonine kinase domains and is homologous to proteins of the myosin light chain kinase family. At least one kinase domain is active and capable of autophosphorylation. In the genome, all four isoforms share the middle three of the five exons of APEG-1, and they differ from each other by using different 5'- and 3'-ends and alternative splicing. We show that the expression of SPEGalpha and SPEGbeta is developmentally regulated in the striated muscle during C2C12 myoblast to myotube differentiation in vitro and cardiomyocyte maturation in vivo. This developmental regulation suggests that both SPEGalpha and SPEGbeta can serve as sensitive markers for striated muscle differentiation and that they may be important for adult striated muscle function.

Transforming growth factor-beta 1 inhibition of macrophage activation is mediated via Smad3

Activated macrophages are critical cellular participants in inflammatory disease states. Transforming growth factor (TGF)-beta1 is a growth factor with pleiotropic effects including inhibition of immune cell activation. Although the pathway of gene activation by TGF-beta1 via Smad proteins has recently been elucidated, suppression of gene expression by TGF-beta1 remains poorly understood. We found that of Smad1-Smad7, Smad3 alone was able to inhibit expression of markers of macrophage activation (inducible nitric-oxide synthase and matrix metalloproteinase-12) following lipopolysaccharide treatment in gene reporter assays. Transient and constitutive overexpression of a dominant negative Smad3 opposed the inhibitory effect of TGF-beta1. Domain swapping experiments suggest that both the Smad MH-1 and MH-2 domains are required for inhibition. Mutation of a critical amino acid residue required for DNA binding in the MH-1 of Smad3 (R74A) resulted in the loss of inhibition. Transient overexpression of p300, an interactor of the Smad MH-2 domain, partially alleviated the inhibition by TGF-beta1/Smad3, suggesting that inhibition of gene expression may be due to increased competition for limiting amounts of this coactivator. Our results have implications for the understanding of gene suppression by TGF-beta1 and for the regulation of activated macrophages by TGF-beta1.

Radon and cigarette smoking: perceptions of this synergistic health risk

Past approaches to the measurement of the perceived risk of combined hazards have failed to demonstrate awareness of synergy (S. E. Hampson et al., 1998; D. Hermand, E. Mullet, & B. Coutelle, 1995; D. Hermand, E. Mullet, & S. Lavieville, 1997). Respondents (N = 650) were provided with information about the synergistic risk of lung cancer from the combination of smoking and radon, and their risk perceptions were assessed on two occasions. At Time 1, using Likert-type scales, there was no evidence of synergistic risk perception. At Time 2, using a scale based on the appraisal of relative risk with anchors allowing for the expression of synergy, the combined hazard of radon and smoking was rated as significantly more of a health risk than the single hazards. The findings are discussed in terms of methodological issues in assessing synergistic risk.

Role of gut-enriched Krüppel-like factor in colonic cell growth and differentiation

Cancer cells differ from normal cells in many aspects, including hyperproliferation and loss of differentiation. Recent research has focused on the role of transcription factors in regulating abnormal cell growth. Gut-enriched Krüppel-like factor (GKLF) is a newly identified eukaryotic zinc finger protein expressed extensively in the gastrointestinal tract. In the current study, we demonstrated that GKLF mRNA levels were significantly decreased in the dysplastic epithelium of the colon, including adenomatous polyp and cancer. GKLF immunostains in the normal colon were higher at the surface epithelium and gradually decreased toward the crypt, but this gradient was not present in the adenomatous and cancerous mucosa. Constitutive overexpression of GKLF DNA in a human colonic adenocarcinoma cell line (HT-29) decreased [(3)H]thymidine incorporation, whereas suppression of GKLF gene increased DNA synthesis, indicating that downregulation of the GKLF gene might contribute to cellular hyperproliferation. Cyclin D1 (CD1) protein level and CD1-associated kinase activity were decreased in HT-29 cell overexpressed GKLF cDNA, and CD1 promoter activity was profoundly suppressed by GKLF. When HT-29 cells were cultured in the presence of sodium butyrate, GKLF mRNA levels increased as cells acquired more differentiated phenotypes. These results suggest that GKLF plays an important role in regulating cell growth and differentiation in the colonic epithelium and that downregulation of GKLF expression may cause colonic cells to become hyperproliferative. Furthermore, GKLF appears to be a transcriptional repressor of the CD1 gene.

Conscientiousness, perceived risk, and risk-reduction behaviors: a preliminary study

Participants (N = 343) from an Oregon community completed surveys at baseline, 3 months, and 12 months to assess personality, the perceived health risk of radon in combination with smoking, and changes in smoking behavior. Conscientiousness predicted instituting a more restrictive household smoking rule (p < .01), and perceived risk predicted reduction in cigarettes smoked per day for men (p < .001). Perceived risk predicted a reduction in the proportion of cigarettes smoked in the home for those who had high (p < .05) but not low or moderate levels of Conscientiousness, a dimension in one personality model. The results demonstrate the importance of Conscientiousness in the prediction of health behavior, particularly behavior that affects others as well as oneself.

Using radon risk to motivate smoking reduction: evaluation of written materials and brief telephone counselling

OBJECTIVE

Radon and cigarette smoking have synergistic effects on lung cancer, even when radon concentrations are relatively low. Working through an electric utility company, we sought to reach smoking households with low radon concentrations and motivate smoking cessation or prohibiting smoking in the home.

DESIGN

Eligible homes (n = 714) were randomised to receive: (1) the Environmental Protection Agency's (EPA's) "A citizen's guide to radon"; (2) a specially developed pamphlet; or (3) that pamphlet plus brief telephone counselling.

PROCEDURE

Utility company "bill stuffers" offered free radon test kits to smoking households. All households received radon test results with an explanatory cover letter. Both the specially developed pamphlet and the telephone counselling emphasised that smoking cessation or prohibiting smoking in the home were the optimal risk reduction strategies. Households were followed up at 3 and 12 months after receiving materials.

RESULTS

The specially developed pamphlet and the EPA guide yielded similar outcomes. There was a non-significant trend for telephone counselling to produce greater sustained quitting than the specially developed pamphlet, and phone counselling led to significantly more new household smoking bans.

CONCLUSIONS

Working through a public utility company is an efficient way to reach smoking households, and brief telephone counselling is a promising method for promoting household smoking bans and cessation in homes alerted to the risk posed by the combination of radon and smoking.

Transforming growth factor-beta 1 inhibits cytokine-mediated induction of human metalloelastase in macrophages

Matrix metalloproteinases (MMP) have been identified in vulnerable areas of atherosclerotic plaques and may contribute to plaque instability through extracellular matrix degradation. Human metalloelastase (MMP-12) is a macrophage-specific MMP with broad substrate specificity and is capable of degrading proteins found in the extracellular matrix of atheromas. Despite its potential importance, little is known about the regulation of MMP-12 expression in the context of atherosclerosis. In this study, we report that in human peripheral blood-derived macrophages, MMP-12 mRNA was markedly up-regulated by several pro-atherosclerotic cytokines and growth factors including interleukin-1beta, tumor necrosis factor-alpha, macrophage colony-stimulating factor, vascular endothelial growth factor, and platelet-derived growth factor-BB. In contrast, the pleiotropic anti-inflammatory growth factor transforming growth factor-beta1 (TGF-beta1) inhibited cytokine-mediated induction of MMP-12 mRNA, protein, and enzymatic activity. Analyses of MMP-12 promoter through transient transfections and electrophoretic mobility shift assays indicated that both its induction by cytokines and its inhibition by TGF-beta1 depended on signaling through an AP-1 site at -81 base pairs. Moreover, the inhibitory effect of TGF-beta1 on MMP-12 was dependent on Smad3. Taken together, MMP-12 is induced by several factors implicated in atherosclerosis. The inhibition of MMP-12 expression by TGF-beta1 suggests that TGF-beta1, acting via Smad3, may promote plaque stability.

Universal healthcare: a bold proposal

One problem with the American health-care system today is not that it's too expensive but that it's too wasteful. The amount spent on health-care in the United States is sufficient to take care of the medical needs of every citizen. The reason that it does not is that the money is far too often is misspent. America already is spending 14% of the gross domestic product and yet we have health-care chaos and 44 million uninsured. Another problem is the lack of trust between payors, insurance carriers, regulators, employers, employees, providers, and patients. Although the financing aspect of health-care is tremendously important, it is even more important to design a plan to spend the money wisely, align the incentives of insurers, payors, patients, and providers, and restore trust between parties. Otherwise we shall continue to be in chaos regardless of how much money we spend on health-care. In this article, we outline our proposal for an ideal comprehensive national health-care plan that will guarantee that we spend our health-care dollars wisely. Our plan would cover all Americans, including the 44 million uninsured, and it would do so at less than the cost of the current system. Because insurance companies are not equipped to oversee medical practice, our plan would place the day-to-day management of the health-care system in the hands of physicians and local physician-run, physician-owned "provider groups." The physicians in these provider groups would be charged with two primary responsibilities: 1) clinically, they would be responsible for providing total quality cradle-to-grave health-care for every patient in their group and 2) economically, they would be responsible for the budget and to spend it wisely. Physicians will be compensated fee-for-service plus an incentive for efficiency, patient satisfaction, and outcome in a broad sense. Physicians would enjoy wide latitude in clinical decision-making without being second-guessed by distant third parties. Our plan places the fiscal responsibility on physicians while at the same time establishing a system of checks and balances to ensure that patients are protected and well cared for. Unlike outwardly similar plans, under this proposal the physicians are owners of the provider groups and the incentives between payors, insurers, providers, and patients are better aligned. It will eliminate the debate about giving patients the right to sue health plans and employers. It would empower large legally organized physician groups to negotiate with insurers. Our plan is a model for spending money wisely. We believe it would benefit, and therefore be embraced, by all parties--physicians, other healthcare providers, employers, insurance companies, the government, and above all the American public.