26 research outputs found
Abstract 1446: Effect of PF-03475952, a potent and neutralizing CD44 antibody, on cancer cell apoptosis in vitro and metastasis in two orthotopic models
No full textAbstract
Effect of PF-03475952, a potent and neutralizing CD44 antibody, on cancer cell apoptosis in vitro and metastasis in two orthotopic models
Yuli Wang, Jean wang, Gary Li, Amy Jackson-Fisher, Brett Simmons, Eugenia Kraynov, Christy Ji, Baiyong Li, and David Pocalyko
Pfizer Global Research & Development, San Diego, CA 92121
CD44 is a cell surface glycoprotein that has multiple functions. It can act as a receptor for ligands such as hyaluronic acid and osteopontin. Additionally, it can function as co-receptor to modulate the activation of growth factor receptors such as c-met & ERBB. CD44 can also influence cell signaling through interaction with components of the actin cytoskeleton such as the ERM protein.
CD44 expression is increased in many types of human cancer. It is also a cell surface marker for cancer stem cells in breast cancer and HCC. In HCC, CD44 overexpression is a frequent event (∼30% based on several reports) and CD44 up regulation is associated with metastasis and poor patient survival. Down regulation of CD44 with RNAi knockdown or neutralizing antibody has been reported to reduce tumor metastasis, recurrence, and growth in different models.
PF-03475952 is a fully human IgG2 anti-CD44 monoclonal antibody that was initially developed as a potential therapeutic agent for rheumatoid arthritis. It was shown previously that the PF-03475952 can disrupt the interaction of CD44 with its ligand, hyaluronic acid. The antibody binding induces loss of CD44 from the cell surface, and inhibits LPS-induced cytokine release from various leukocytes.
In this report, we evaluated the potential of PF-03475952 as a cancer adjuvant therapy for HCC. HCC is the third most deadly forms of cancer world-wide with frequent early recurrence due to inter and extra hepatic metastasis. The effect of PF-03475952 on cancer metastasis was first demonstrated in an M24met melanoma model. The expression of CD44 and the effects of PF-03475952 on HCC cell lines were then characterized. In vitro, PF-03475952 was able to reduce cell adhesion and promote apoptosis in a CD44-dependent manner. More importantly, PF-03475952 can reduce lung metastasis in a CD44-positive HCC orthotopic model.
The study suggested that the CD44 neutralizing antibody, PF-03475952, could be an efficacious agent as adjuvant therapy to prevent cancer metastasis.
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 1446.</jats:p
Abstract 5371: Effect of DNA methyltransferase inhibitor 5-azacitidine on 3D chromatin structure measured by Hi-C
No full textAbstract
Therapies targeting epigenetic modifiers such as the DNA methyltransferase (DNMT) inhibitor, 5-azacytidine (Aza), are used in treating hematologic malignancies and also show promising results in subsets of solid tumors. The molecular mechanisms for these results, however, are not fully understood. Nonetheless, a number of clinical studies using combinations of epigenetic therapies plus chemo or immunotherapy to enhance the tumor response are ongoing. HCT-116, a colon cancer cell line genetically defined by microsatellite instability (MSI), resulting in a highly mutated, yet primarily diploid genome, has been routinely used to study epigenetic mechanisms and response to DNMT inhibition. In a previous study, we integrated a combination of data types including DNA methylation, DNA accessibility, histone modifications and transcriptomic data that revealed strong correlations between epigenomic changes and gene expression following Aza treatment. However, for some genes, we could not predict expression changes using these unidimensional, region-specific analysis methods. As others have demonstrated, genes do not work as single, isolated units, but rather interact with distal regulatory elements. These regulatory elements, often several Mb away can control gene expression through physical interactions such as bending and looping. We reason that in addition to direct demethylation of the immediate regulatory elements within the gene, Aza treatment can affect long-range chromosomal communications. In order to further understand the chromatin remodeling effect of Aza treatment, we performed high resolution genome-wide chromosome conformation capture (Hi-C) followed by NGS. HCT-116 cells were treated with DMSO or 1 μM Aza for 42 and 96 hours. Hi-C and RNA-Seq data was analyzed and integrated with other datatypes. The results showed that AZA treatment alters topologically associating domains (TAD), with the formation of new TAD boundaries and disappearance of others. The genome was then separated into 25K base pair consecutive bins, with each bin marked as type A (active) or type B (inactive). We observed bin switching following AZA treatment and differential loop formations (e.g. promoter-enhancer). Bins that switched from B to A at both time points were found enriched in genes that are related to acute phase response, interferon pathway, and cancer including PI3KCB, DDX58, CD274 and CDKN2A. Our findings using Hi-C were found to be in agreement with previous results using alternative experimental methods, which identified Aza and CTCF as the top upstream regulators of these genes. Our data also suggests that overall changes in 3D chromatin activities measured by Hi-C could be a better predictor of transcriptional regulation compared to H2K27me3 and H3K4me3 alone, particularly in situations where there are no significant changes in those marks but where changes in gene expression exist.
Citation Format: Yuchen Vincent Bai, John Whitaker, Emanuele Palescandolo, Vinod Krishna, Vipul Bhargava, Satya Saxena, Xiang Yao, David Pocalyko, Kurt Bachman. Effect of DNA methyltransferase inhibitor 5-azacitidine on 3D chromatin structure measured by Hi-C [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5371. doi:10.1158/1538-7445.AM2017-5371</jats:p
Elevated fibroblast growth factor-inducible 14 expression promotes gastric cancer growth via nuclear factor-κB and is associated with poor patient outcome
No full textThe fibroblast growth factor-inducible 14 (Fn14) gene encodes a type I transmembrane protein that belongs to the tumor necrosis factor receptor superfamily and regulates multiple cellular processes in diverse physiological and pathological conditions, including cancer. Here, we describe an important role for Fn14 in regulating the growth of gastric cancer cells. Previous gene expression data analysis demonstrated that Fn14 was up-regulated in various tumor tissues, including gastric cancer. Using qRT-PCR, we showed that Fn14 was overexpressed in gastric tumor tissues compared to normal tissues. Furthermore, Fn14 expression levels were inversely correlated with gastric cancer patient survival. Using ectopic overexpression and shRNA-mediated knockdown of Fn14, we demonstrated that the expression level of Fn14 affected cell growth in gastric cancer. The effect of Fn14 on cell growth was mediated by the NF-κB activity and eventually by the transcriptional regulation of the anti-apoptotic Bcl-2 family gene (Bcl-xL). These results suggest that Fn14 may play an important role in gastric tumor growth by regulating NF-κB-mediated anti-apoptosis and that Fn14 may be a useful prognostic marker for gastric cancer.open
Abstract 4177: Inhibition of tumor malignancy by anti-angiogenic therapies in orthotopic mouse models of hepatocellular carcinoma
No full textAbstract
Hepatocellular carcinoma (HCC) is the most common liver malignancy, and the third most common cause of cancer-related mortalities worldwide. Most cases occur in Asia, and in China alone an estimated 251,000 male and 95,000 female patients are diagnosed annually. Although significant advances have been made with the use of certain chemotherapeutic and targeted therapeutic agents in HCC treatment, the prognosis for most liver cancer patients remains poor. To address this significant unmet medical need, Pfizer Oncology has set out to strengthen its research and drug discovery activities targeting HCC. Here we report the establishment of two series (cell line-derived and primary human tumor-derived) of orthotopic mouse models of HCC, and their validation with anti-angiogenic compounds sutent and axitinib. In both series of models, tumor fragments obtained from in vivo expansion were surgically implanted into the left lobe of mouse liver to mimic the natural microenvironment and preserve the interaction between tumor cells and the stroma components. Both sutent and axitinib demonstrated significant anti-tumor activity, as well as metastatic potential at therapeutic doses. The anti-tumor activity of these agents are associated with reduction of CD31 in the tumor. Both sutent and axitinib were well tolerated by the animals during the course of the studies. In addition, plasma samples were collected at different time points for α-feto-protein (AFP) measurement. A significant correlation between tumor size (or weight) and serum AFP level was demonstrated, which indicated that circulating AFP can be utilized as a non-invasive biomarker for HCC burden. These results support anti-angiogenesis as a valid approach for effective treatment of HCC.
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 4177.</jats:p
Regulation of hypoxia responses by flavin adenine dinucleotide‐dependent modulation of <scp>HIF</scp> ‐1α protein stability
No full textOxygen deprivation induces a range of cellular adaptive responses that enable to drive cancer progression. Here, we report that lysine-specific demethylase 1 (LSD1) upregulates hypoxia responses by demethylating RACK1 protein, a component of hypoxia-inducible factor (HIF) ubiquitination machinery, and consequently suppressing the oxygen-independent degradation of HIF-1α. This ability of LSD1 is attenuated during prolonged hypoxia, with a decrease in the cellular level of flavin adenine dinucleotide (FAD), a metabolic cofactor of LSD1, causing HIF-1α downregulation in later stages of hypoxia. Exogenously provided FAD restores HIF-1α stability, indicating a rate-limiting role for FAD in LSD1-mediated HIF-1α regulation. Transcriptomic analyses of patient tissues show that the HIF-1 signature is highly correlated with the expression of LSD1 target genes as well as the enzymes of FAD biosynthetic pathway in triple-negative breast cancers, reflecting the significance of FAD-dependent LSD1 activity in cancer progression. Together, our findings provide a new insight into HIF-mediated hypoxia response regulation by coupling the FAD dependence of LSD1 activity to the regulation of HIF-1α stability.
Abstract 462: Targeting hepatocellular carcinoma by suppressing HIF-1 alpha alone and in combination with therapeutic drugs
No full textAbstract
Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the third most common cause of cancer related death. HIF-1 alpha (HIF1α) is overexpressed in many human cancers as a result of intratumoral hypoxia as well as genetic alterations, such as gain-of-function mutations in oncogenes and loss-of-function mutations in tumour-suppressor genes. It has many important functions including angiogenesis, survival, chemo-resistance metastasis, and glucose metabolism. The overexpression of HIF1α is associated with poor prognosis in many types of cancer. To understand the role of HIF1α in HCC, we analyzed the HIF1α gene expression in the clinical tumor tissues and found that HIF1α mRNA was upregulated compared with the non-tumor adjacent tissue. This upregulation was positively correlated with the poor overall survival and disease free survival of the HCC patients. In addition, we knocked down the HIF1α expression by siRNA and examined its impact on the growth of a panel of HCC cell lines under both hypoxia and normaxia conditions. HIF1α siRNA suppressed 90% of HIF1α mRNA and 50% of its protein expression without affecting the expression of HIF1β and HIF2α. Hep1 and Snu182 cell lines were sensitive to HIF1α suppression (&gt;70%) while Huh 7.5 and SNU398 showed little response. The effect of HIF1α on cell growth inhibition is similar under both hypoxia and normoxia conditions. PDGFR and mTOR were reported to regulate HIF1α synthesis. We examined the efficacy of rapamycin and PDGFR inhibitors in combination with HIF1α siRNA. We found differential response in different HCC cell lines. Rapamycin had limited suppression on both Hep1 and SNU182 cell growth. When combined with HIF1α siRNA, we observed significantly enhanced suppression. PDGFR inhibitor suppressed Hep1 and SNU182 in a dose-dependant manner and the efficacy was further enhanced when combined with HIF1α. To understand the molecular mechanism of HIF1α function, we carried out the gene expression analysis on these “sensitive” and “resistant” cell lines under different treatment conditions. The differential expression signature will provide important insight to the function of HIF1α and the other targeted therapeutic drugs in these HCC cell lines. It will also provide understanding of possible resistance mechanisms and combinational drug strategy to overcome these resistances.
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 462.</jats:p
Integrative Analysis of DiseaseLand Omics Database for Disease Signatures and Treatments: A Bipolar Case Study
No full textTranscriptomics technologies such as next-generation sequencing and microarray platforms provide exciting opportunities for improving diagnosis and treatment of complex diseases. Transcriptomics studies often share similar hypotheses, but are carried out on different platforms, in different conditions, and with different analysis approaches. These factors, in addition to small sample sizes, can result in a lack of reproducibility. A clear understanding and unified picture of many complex diseases are still elusive, highlighting an urgent need to effectively integrate multiple transcriptomic studies for disease signatures. We have integrated more than 3,000 high-quality transcriptomic datasets in oncology, immunology, neuroscience, cardiovascular and metabolic disease, and from both public and internal sources (DiseaseLand database). We established a systematic data integration and meta-analysis approach, which can be applied in multiple disease areas to create a unified picture of the disease signature and prioritize drug targets, pathways, and compounds. In this bipolar case study, we provided an illustrative example using our approach to combine a total of 30 genome-wide gene expression studies using postmortem human brain samples. First, the studies were integrated by extracting raw FASTQ or CEL files, then undergoing the same procedures for preprocessing, normalization, and statistical inference. Second, both p-value and effect size based meta-analysis algorithms were used to identify a total of 204 differentially expressed (DE) genes (FDR < 0.05) genes in the prefrontal cortex. Among these were BDNF, VGF, WFS1, DUSP6, CRHBP, MAOA, and RELN, which have previously been implicated in bipolar disorder. Finally, pathway enrichment analysis revealed a role for GPCR, MAPK, immune, and Reelin pathways. Compound profiling analysis revealed MAPK and other inhibitors may modulate the DE genes. The ability to robustly combine and synthesize the information from multiple studies enables a more powerful understanding of this complex disease
