Target For Cancer Prevention Research Articles

AMPK: Therapeutic Target for Diabetes and Cancer Prevention.

AMP-activated protein kinase (AMPK) is a protein kinase that maintains homeostasis in cells and organs. As a master regulator of metabolism, AMPK coordinates many metabolic reactions. AMPK is a key factor in diabetes and metabolic syndrome associated with dysregulation of the metabolic status. Recently, AMPK has also attracted attention as a tumor suppressor. The aim of this article is to discuss about the role of AMPK in diabetes as well as cancer and to evaluate its effectiveness in treatment and prevention of these diseases. We reviewed studies of signaling mechanism involving AMPK and research on the role of AMPK in human disease including diabetes and cancer. In particular, we focused our attention on clinical trials about cancer treatment and prevention targeting AMPK. Many experimental studies reported the relation of AMPK and various metabolic reactions, mainly regulating energy homeostasis. Recent studies showed effect of AMPK on arrest of cell cycle as well as suppression of inflammation, which are important factors for carcinogenesis. Although some clinical studies investigated cancer treatment and prevention targeting AMPK, the effective yields in clinical trial have been limited. AMPK activation as represented by metformin showed to improve disorders associated with diabetes and metabolic syndrome and became a well-established treatment strategy for these diseases. The increasing evidence suggests that AMPK is a promising target in the treatment and prevention of cancer. Further investigation including long-term clinical trials with large sample size is needed.

Molecular Mechanisms and Pathways as Targets for Cancer Prevention and Progression with Dietary Compounds.

A unique feature of bioactive food ingredients is their broad antioxidant function. Antioxidants having a wide spectrum of chemical structure and activity beyond basic nutrition; display different health benefits by the prevention and progression of chronic diseases. Functional food components are capable of enhancing the natural antioxidant defense system by scavenging reactive oxygen and nitrogen species, protecting and repairing DNA damage, as well as modulating the signal transduction pathways and gene expression. Major pathways affected by bioactive food ingredients include the pro-inflammatory pathways regulated by nuclear factor kappa B (NF-κB), as well as those associated with cytokines and chemokines. The present review summarizes the importance of plant bioactives and their roles in the regulation of inflammatory pathways. Bioactives influence several physiological processes such as gene expression, cell cycle regulation, cell proliferation, cell migration, etc., resulting in cancer prevention. Cancer initiation is associated with changes in metabolic pathways such as glucose metabolism, and the effect of bioactives in normalizing this process has been provided. Initiation and progression of inflammatory bowel diseases (IBD) which increase the chances of developing of colorectal cancers can be downregulated by plant bioactives. Several aspects of the potential roles of microRNAs and epigenetic modifications in the development of cancers have also been presented.

Gastric cancer: Basic aspects.

Gastric cancer is one of the most incident and deadliest malignancies in the world. Gastric cancer is a heterogeneous disease and the end point of a long and multistep process, which results from the stepwise accumulation of numerous (epi)genetic alterations, leading to dysregulation of oncogenic and tumor suppressor pathways. Gastric cancer stem cells have emerged as fundamental players in cancer development and as contributors to gastric cancer heterogeneity. For this special issue, we will report last year's update on the gastric cancer molecular classification, and in particular address the gastric cancer groups who could benefit from immune checkpoint therapy. We will also review the latest advances on gastric cancer stem cells, their properties as gastric cancer markers and therapeutic targets, and associated signaling pathways. The understanding of the molecular basis underlying gastric cancer heterogeneity and of the role played by gastric cancer stem cells in cancer development and heterogeneity is of major significance, not only for identifying novel targets for cancer prevention and treatment, but also for clinical management and patient stratification for targeted therapies.

Sulforaphane reduces YAP/∆Np63α signaling to reduce cancer stem cell survival and tumor formation.

Epidermal squamous cell carcinoma (SCC) is among the most common cancers. SCC can be treated by surgical excision, but recurrence of therapy-resistant disease is a major problem. We recently showed that YAP1, the Hippo signaling transcription adaptor protein, and ∆Np63α, a key epidermal stem cell survival protein, form a complex to drive epidermal cancer stem cell survival. In the present study, we demonstrate that YAP1 and ∆Np63α are important sulforaphane cancer prevention targets. We show that sulforaphane treatment increases YAP1 phosphorylation and proteolytic degradation. The loss of YAP1 is associated with a reduction in ∆Np63α level and a reduction in ECS cell survival, spheroid formation, invasion and migration. Loss of YAP1 and ∆Np63α is mediated by the proteasome and can be inhibited by lactacystin treatment. YAP1 or ∆Np63α knockdown replicates the responses to sulforaphane, and restoration of YAP1 or ∆Np63α antagonizes sulforaphane action. Sulforaphane suppresses ECS cell tumor formation and this is associated with reduced levels of YAP1 and ∆Np63α. These studies suggest that YAP1 and ∆Np63α may be important sulforaphane cancer preventive targets in epidermal squamous cell carcinoma.

Polyphenolic Nutrients in Cancer Chemoprevention and Metastasis: Role of the Epithelial-to-Mesenchymal (EMT) Pathway.

The epithelial-to-mesenchymal transition (EMT) has received significant interest as a novel target in cancer prevention, metastasis, and resistance. The conversion of cells from an epithelial, adhesive state to a mesenchymal, motile state is one of the key events in the development of cancer metastasis. Polyphenols have been reported to be efficacious in the prevention of cancer and reversing cancer progression. Recently, the antimetastatic efficacy of polyphenols has been reported, thereby expanding the potential use of these compounds beyond chemoprevention. Polyphenols may affect EMT pathways, which are involved in cancer metastasis; for example, polyphenols increase the levels of epithelial markers, but downregulate the mesenchymal markers. Polyphenols also alter the level of expression and functionality of important proteins in other signaling pathways that control cellular mesenchymal characteristics. However, the specific proteins that are directly affected by polyphenols in these signaling pathways remain to be elucidated. The aim of this review is to analyze current evidence regarding the role of polyphenols in attenuating EMT-mediated cancer progression and metastasis. We also discuss the role of the most important polyphenol subclasses and members of the polyphenols in reversing metastasis and targeting EMT. Finally, limitations and future directions to improve our understanding in this field are discussed.

HPV Vaccination: Are We Meeting Our Targets in Cervical Cancer Prevention?

Purpose of Review The purpose of this review is to update the reader on the most recent HPV vaccine uptake rates in boys and girls in the United States and to summarize the recent recommendations for vaccination. The review also evaluates a decade of data demonstrating the safety and efficacy of the HPV vaccine and discusses disparities in vaccine uptake in the US. Finally, we will summarize the scope of attempted and proposed interventions to improve vaccine uptake in the United States.

AGEs, RAGEs and s-RAGE; friend or foe for cancer.

Impaired awareness of glycation biology in cancer initiation and progression is one of the fundamental reasons for its meticulous investigation of the molecules involved in signalling pathway. Glycation of biological macromolecules results in the progression of advanced glycation end-products (AGEs) that proliferates the process of carcinogenesis by activation of transcription factors and release of cytokines. The receptor for advanced glycation end-products (RAGEs) with the binding of its different ligands like; AGEs, HMGB1 and S100 activate the signalling arrays. The activation of downstream signalling pathway ultimately leads to the pathophysiological conditions of diabetes, ageing, neurological disorders and cancers as well as a result of the activation of transcription factors which is discussed in the main body text of this review. However, there might be a likelihood of the positive effect of the HMGB1 and S100 proteins in cancer. Still, some untouched mechanisms might be responsible for the establishment of the function of AGE-RAGE or AGE-sRAGE axis activation that leads to the friend-foe association with the cancers. The levels of RAGE and s-RAGE may be a useful biomarker of ligand-RAGE pathway activation and cancer. Thus, the possibility of providing a potential complement to carcinogenesis is very high which might be an interesting target for therapeutic interventions. This article is an insightful assessment on AGE, RAGE and s-RAGE for its possible role in cancer onset and progression. The novel therapeutic targets for cancer prevention or inhibition are also explained in brief in relation to AGE and RAGE.

Abstract 4326: Tissue density can create a carcinogenic microenvironment for normal mammary epithelial cells

Abstract Background Breast cancer is the most diagnosed cancer and the fourth leading cause of cancer related mortality among females. Mammographic density (MD) is defined by the amount of stromal and epithelial tissues present in the breast tissue. Fifty percent of women have high MD and are 4-6 times more likely to develop breast cancer in their lifetime compared to women with low MD. Additionally, mammograms often miss abnormal lesions in high MD breast leading to late-stage diagnosis. The stromal microenvironment is characterized by extracellular matrix (ECM) reorganization and stiffness, and increase in ECM proteins including collagen I and fibronectin, which drives proliferation, tumor cell survival and migration. Expression of fibronectin and collagen are significantly higher in women with high MD compared to women with low MD. However, the mechanisms underlying the initiation and progression of breast cancer associated with MD remains largely unknown. Therefore, understanding the molecular pathways involved in the unique transformation of normal mammary cells to cancer cells in a dense microenvironment is an important step in finding diagnostic tools and therapeutic targets for prevention and treatment of breast cancer. We hypothesize that normal mammary epithelial cells behave like cancer cells in an ECM protein-rich microenvironment by activating pathways associated with tumor growth and survival and contributing to the initiation and progression of breast cancer. Methods We conducted an in vitro study, determining the effects of different concentrations of ECM proteins on the activation of pro-carcinogenic pathways including the MAPK pathway and the PI3 Kinase pathway using Western blotting analysis. This study helps us understand if there is a difference in the expression of ERK1/2 signaling and/or PI3 Kinase signaling in normal mammary cells (hTERT) seeded on culture dish coated with ECM-proteins (collagen and fibronectin), compared to a non-coated control. We also examined morphological changes that can occur in a breast cancer cell line (HCC1806) that are seeded on ECM-rich coating dishes compared to non-coated dishes. Results We observed changes in the morphology of breast cancer cell lines after cells were seeded on increasing concentration of extracellular matrix coatings using light microscopy. We also observed an increase in the expression of PI3 Kinase in normal mammary cell lines compared to control after cells were stressed using hypoxia. Conclusion Collagen and fibronectin-rich microenvironment can induce desmoplastic-like phenotype and behavior for normal mammary cells, which highlights the possible first steps in transformation of normal mammary cells to desmoplastic cells. Given that high MD is one of the major risk factors for breast cancer development, it is critical to decipher the molecular mechanisms associated with the high risk. Citation Format: Shayan Nazari, Pinku Mukherjee. Tissue density can create a carcinogenic microenvironment for normal mammary epithelial cells [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 4326. doi:10.1158/1538-7445.AM2017-4326

Abstract 2804: Identifying therapeutically relevant mouse and patient-derived xenograft (PDX) models of human cancer using the mouse tumor biology database (MTB) data resource

Abstract The laboratory mouse is the foremost model organism for interrogating the genetic and molecular basis of human cancer and is a powerful platform for identifying therapeutically effective targets for prevention and treatment of cancer. Research using genetically engineered mouse models (GEMMs) have led to important advances in our understanding of the genetic basis of cancer susceptibility, the function of tumor suppressors and oncogenes, and therapy responses in preclinical and co-clinical studies. Patient Derived Xenograft (PDX) models are an increasingly important model system for in vivo studies of human cancer. These models are created by implanting patient tumors into immunodeficient or humanized mouse hosts and are a powerful translational research platform for preclinical and co-clinical studies. The number of GEMM and PDX mouse models increases significantly every year and the diverse cancer-related data about human cancer models tend to be distributed in ways that makes it difficult for researchers to integrate and interpret the information to find the most relevant model for their research. The Mouse Tumor Biology database (http://tumor.informatics.jax.org) is an expertly curated resource for information and data about genetically defined mouse strains and PDX models of human cancer. MTB provides query tools to enable integrated searches and visualization of these varied data, thus facilitating the assessment of novel mouse models of human cancer and potential preventative and therapeutic treatments. Enforcement of controlled vocabularies and standard gene, allele and strain nomenclature within MTB facilitates precise and comprehensive queries of MTB for pertinent mouse models. MTB contains data from spontaneous or endogenously induced tumors from genetically defined mice including tumor classification, incidence, Quantitative Trait Loci, pathology reports, images and genetic changes in the tumor (somatic) and background strain (germline) genomes. The PDX resource enables queries based on tumor type, cancer diagnosis and genomic properties of the engrafted tumors. Information in MTB is obtained from curation of peer-reviewed scientific publications and direct data submissions from individual investigators and large-scale programs. New features in MTB include the Faceted Tumor Search Form and a Reported Mouse Models table linking the most common fatal human cancers to reported equivalent mouse models. MTB contains over 77,000 Tumor Frequencies and over 2,200 Pathology Reports with over 6,600 images from over 4,200 references. MTB provides access to detailed clinical, pathological, expression and genomics data from over 400 PDX models. Information in MTB is integrated with cancer models data from other bioinformatics resources including PathBase, the Gene Expression Omnibus and ArrayExpress. MTB is supported by NCI grant CA089713. Citation Format: Dale A. Begley, Debra M. Krupke, Steven B. Neuhauser, Joel E. Richardson, John P. Sundberg, Janan T. Eppig, Carol J. Bult. Identifying therapeutically relevant mouse and patient-derived xenograft (PDX) models of human cancer using the mouse tumor biology database (MTB) data resource [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 2804. doi:10.1158/1538-7445.AM2017-2804

Abstract LB-213: Thrombospondin-1 regulates intestinal microbiota and bile acid metabolism in a murine model of colorectal cancer

Abstract Colon cancer is major public health concern with over 50,000 deaths annually in the US. Environmental and genetic factors influence colon cancer progression, and expression of thrombospondin-1 (TSP1) inversely correlates with colon cancer aggressiveness. TSP1 is a matricellular protein that regulates vascular physiology and tissue responses to stress. We previously demonstrated that deleting the TSP1 (Thbs1) gene in ApcMin/+ mice results in systemic metabolic changes as assessed in liver tissue, increased tumorigenesis, and lower survival of mice fed a low fat diet. We now show that TSP1 induces changes in intestinal microbiota that may cause shifts in secondary bile acid metabolism that influence colon carcinogenesis. Mice were maintained and bred at least two generations on a low fat western diet to equalize dietary effects on their epigenetic context and microbiomes. Mice were pair-fed a low fat or a 21% high-fat western diet beginning at weaning. Mouse fecal matter was collected 8 weeks after dietary exposures and subjected to 16S sequencing for bacterial population identification. Lactobacillaceae, Lachnopiraceae, Ruminococcacea, Verrucomicrobiaceae families were present in all groups. The family Verrucomicrobiaceae and its genus Akkemensi represented a high proportion of the bacterial population. The relative levels of Akkemensia were elevated in low fat fed mice in mice ApcMin/+ and Thbs1−/−:ApcMin/+ when compared to WT counterparts. Interestingly Akkenmensia abundance was reduced in ApcMin/+ mice fed a high-fat diet when compared to other groups. The relative population of the genus Ruminococcus was reduced in Thbs1−/− mice as well as in Thbs1−/−:ApcMin/+ mice fed low and high fat diets, suggesting that these population shifts are driven by genotype. Because intestinal bacteria can alter metabolism, particularly of bile acids, we collected large intestine tissue from mice and subjected it to metabolomics analysis. Our data showed primary and secondary bile metabolism were regulated by the absence of TSP1 in mice fed a high fat diet when compared to WT. High 6-beta-hydroxylithocholate levels were associated with onset of carcinogenesis since it was elevated in ApcMin/+ and Thbs1−/−:ApcMin/+ mice but not in WT or Thbs1−/−. 6-oxolithocholate, hyocholate and hyodeoxycholate were elevated only in ApcMin/+ mice fed a high fat diet but not in Thbs1−/−:ApcMin/+, suggesting that these metabolites contribute to the shift in survival and carcinogenesis observed between low and high fat diets. On the other hand levels of taurohyodeoxycholic acid, 3-dehydrocholate, 7-ketodeoxycholate were elevated in Thbs1−/−:ApcMin/+ and Thbs1−/− mice but not in ApcMin/+, indicating that changes in these metabolites are driven by the loss of Thbs1 and may pre-dispose mice to increased carcinogenesis when fed a high fat diet. Taken together our data shows an unexpected role of TSP1 in regulation of microbiota and bile acid metabolism and reveals potential targets for prevention and treatment of colorectal cancer. Citation Format: David R. Soto-Pantoja, John M. Sipes, Brian Westwood, Nicole Morris, Nancy J. Emenaker, David D. Roberts. Thrombospondin-1 regulates intestinal microbiota and bile acid metabolism in a murine model of colorectal cancer [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 LB-213. doi:10.1158/1538-7445.AM2017-LB-213

Abstract 1898: MEG3 as a competing endogenous RNA binds with miR-27a to promote PHLPP2 protein translation, and consequently impairs bladder cancer invasion

Abstract Muscle invasion and metastasis of bladder cancer dramatically decrease survival rate, compared to 77% of 5 year survival rate of all bladder cancer, metastasis bladder cancer is only 5%. This truth implies that one of the therapeutic kernels of bladder cancer is to decrease, even block, its invasiveness. In the current study, we find that MEG3 is significantly downregulate in human muscle-invasive bladder cancer tissues compared with non-muscle invasive tissues. We also demonstrate the MEG3 strongly inhibits human bladder cancer cell invasiveness by acting as a ceRNA. We find that MEG3 competes with PHLPP2 mRNA for miR-27a binding, which leads to a decreased miR-27a activity, and subsequently reducing the translation inhibition of miR-27a to PHLPP2. The upregulated PHLPP2 decreases the c-Jun phosphorylation at Ser63/73, and in turn inhibits the c-Myc transcription and its mediated invasiveness of the bladder cancer cells. This is the first demonstration that MEG3 inhibits the invasiveness of human bladder cancer cells via negative regulation of c-Myc as a ceRNA. These findings not only provides a novel insight into understanding the mechanisms behind the MEG3 inhibiting the cancer cell invasion, but also reveals a potential targets for invasive bladder cancer prevention and therapy. Citation Format: Chao Huang, Xin Liao, Jingxia Li, Chuanshu Huang. MEG3 as a competing endogenous RNA binds with miR-27a to promote PHLPP2 protein translation, and consequently impairs bladder cancer invasion [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 1898. doi:10.1158/1538-7445.AM2017-1898

Abstract 350: Pregnancy at early age is associated with a reduction of progesterone-responsive cells and epithelial Wnt signaling in human breast tissue

Abstract Background: Pregnancy at early age is the most significant modifiable factor which consistently decreases lifetime breast cancer risk. However, the underlying mechanisms haven’t been conclusively identified. Studies in mice suggest a reduction in progesterone-receptor (PR) sensitive epithelial cells as well as a downregulation of the Wnt signaling pathway as being one of the main mechanisms for the protective effect of early pregnancy. The aim of our study was to validate these findings in humans. Methods: We collected benign breast tissue of 123 women who had been stratified according to age at first pregnancy and the occurrence of subsequent breast cancer, and performed immunohistochemistry for PR, Wnt4 and the Wnt-target Versican. Results: The number of PR positive epithelial cells was significantly lower in the group of women with early pregnancy and no subsequent breast cancer compared to the group of nulliparous women with subsequent invasive breast cancer (p=0.017). In women with early pregnancy, expression of Versican and Wnt4 was significantly lower compared to nulliparous women (p=0.0064 and p=0.0156 respectively), and Versican expression was also significant lower compared to women with late pregnancy (p<0.0001). Discussion: Our results confirm prior observations in mice and suggest a role of downregulation of epithelial Wnt signaling in the protective effect of early pregnancy in humans. This results in a decreased proliferation of stem/progenitor cells; therefore, the Wnt signaling pathway may represent a potential target for breast cancer prevention in humans. Citation Format: Robert Mechera, Simone Münst, Silvio Däster, Salvatore Piscuoglio, Charlotte Ng, Fabienne Meier-Abt, Walter P. Weber, Savas D. Soysal. Pregnancy at early age is associated with a reduction of progesterone-responsive cells and epithelial Wnt signaling in human breast tissue [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 350. doi:10.1158/1538-7445.AM2017-350

Abstract 1242: Ornithine decarboxylase as a therapeutic target in endometrial cancer

Abstract Endometrial cancer is the 4th most common cancer and the 6th deadliest cancer in US women. The American Cancer Society estimates there will be 60,050 new endometrial cancers in 2016, an increase of more than 10% from the previous year highlighting the need for more effective treatments and prevention. Ornithine Decarboxylase (ODC) a key enzyme in polyamine synthesis is often overexpressed in cancers and contributes to cell proliferation and tumor growth. Therefore, ODC and the polyamine pathway are considered rational targets for cancer treatment or prevention. We noted ubiquitous expression of ODC1 in our previously published endometrial cancer gene array data and confirmed this in the cancer genome atlas (TCGA), finding expression in all four molecular sub-types with highest expression in copy number high cancers which have the worst clinical outcomes. Therefore, we explored the association of ODC1 gene expression with clinical outcomes of overall survival (OS) and recurrence in the TCGA cohort and noted that elevated ODC1 was significantly related to OS (Wald test p=0.001) and recurrence (p=0.01). Importantly, we confirmed these observations using QRT-PCR in a validation cohort of 60 endometrial cancers and found that endometrial cancers with elevated ODC1 had significantly shorter recurrence-free intervals (p=5.59x10-5) and elevated hazard ratio=3.72. Similar to TCGA data we also noted a strong trend to worse OS ( p=0.00014) with elevated hazard ratio 3.81. Numerous studies including clinical trials have examined the chemopreventive and anti-tumor effects of difluoromethylornithine (DFMO), a specific inhibitor of ODC. We found that DFMO treatment significantly reduced cell proliferation, cell viability, and colony formation in human cell line models derived from undifferentiated, endometrioid, serous, MMT and clear cell endometrial cancers. In contrast, immortalized uterine endometrial epithelial cells (EM E6/E7 TERT1) were less sensitive to DFMO. To confirm the significant effects of DFMO in vitro we performed an in vivo study with human endometrial cancer (ACI-98) tumor-bearing athymic nude mice. Xenografted mice were either treated with 2% (w/v) DFMO supplied in drinking water or water only (n=10/group). DFMO significantly reduced the tumor burden in mice compared to controls (p=0.0023). ODC-regulated polyamines (putrescine [Put] and spermidine [Spd]) known activators of cell proliferation were strongly decreased in response to DFMO, in both tumor tissue ([Put] (p=0.0006), [Spd] (p<0.0001)) and blood plasma ([Put] (p<0.0001), [Spd] (p=0.0049)) of treated mice. Results of these studies indicate that some endometrial cancers appear particularly sensitive to DFMO. Our findings indicate that the polyamine pathway in endometrial cancers in general and specifically those most clinically relevant endometrial cancers could be targeted for effective treatment, chemoprevention or chemoprevention of recurrence. Citation Format: Hong Im Kim, Chad R. Schultz, Andrea L. Buras, Elizabeth Friedman, Alyssa M. Fedorko, Leigh G. Seamon, Gadisetti Chandramouli, André S. Bachmann, John I. Risinger. Ornithine decarboxylase as a therapeutic target in endometrial cancer [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 1242. doi:10.1158/1538-7445.AM2017-1242

Fusobacterium Nucleatum Subspecies Animalis Influences Proinflammatory Cytokine Expression and Monocyte Activation in Human Colorectal Tumors.

Chronic infection and associated inflammation have long been suspected to promote human carcinogenesis. Recently, certain gut bacteria, including some in the Fusobacterium genus, have been implicated in playing a role in human colorectal cancer development. However, the Fusobacterium species and subspecies involved and their oncogenic mechanisms remain to be determined. We sought to identify the specific Fusobacterium spp. and ssp. in clinical colorectal cancer specimens by targeted sequencing of Fusobacterium 16S ribosomal RNA gene. Five Fusobacterium spp. were identified in clinical colorectal cancer specimens. Additional analyses confirmed that Fusobacterium nucleatum ssp. animalis was the most prevalent F. nucleatum subspecies in human colorectal cancers. We also assessed inflammatory cytokines in colorectal cancer specimens using immunoassays and found that expression of the cytokines IL17A and TNFα was markedly increased but IL21 decreased in the colorectal tumors. Furthermore, the chemokine (C-C motif) ligand 20 was differentially expressed in colorectal tumors at all stages. In in vitro co-culture assays, F. nucleatum ssp. animalis induced CCL20 protein expression in colorectal cancer cells and monocytes. It also stimulated the monocyte/macrophage activation and migration. Our observations suggested that infection with F. nucleatum ssp. animalis in colorectal tissue could induce inflammatory response and promote colorectal cancer development. Further studies are warranted to determine if F. nucleatum ssp. animalis could be a novel target for colorectal cancer prevention and treatment. Cancer Prev Res; 10(7); 398-409. ©2017 AACR.

Inflammasome as a Therapeutic Target for Cancer Prevention and Treatment.

Chronic inflammation is a critical modulator of carcinogenesis through secretion of inflammatory cytokines, which leads to the formation of an inflammatory microenvironment. In this process, the inflammasome plays an important role in the expression and activation of interleukin (IL)-1β and IL-18 to promote cancer development. The inflammasome is a multiprotein complex consisting of several nucleotide-binding domain and leucine-rich repeat containing receptor, adaptor proteins, and caspase 1 (CASP1). It senses the various intracellular (damage-associated molecular patterns) and extracellular (pathogen-associated molecular patterns) stimuli. A primed inflammasome recruits adaptor proteins, activates CASP1 to enhance the proteolytic cleavage of pro-IL-1β and IL-18, and sends the signal to respond to each insult. Depending on stimuli and cell contexts, several inflammasomes are closely associated with the initiation and promotion of carcinogenesis. In contrast, inflammasomes also show an ambivalent effect on carcinogenesis by enhancing inflammatory cell death (pyroptosis) and repairing damaged tissues. Although the inflammasome plays a controversial role in carcinogenesis, it may be a promising target for human cancer prevention and treatment. A more in-depth study on the role of the inflammasome in carcinogenesis, based on stimuli, cell contexts, and cancer stages, can lead to the development of novel therapeutic strategies against malignant human cancers.

Regulation of SIRT3 signal related metabolic reprogramming in gastric cancer by Helicobacter pylori oncoprotein CagA.

Injection of the Helicobacter pylori cytotoxin-associated gene A (CagA) is closely associated with the development of chronic gastritis and gastric cancer. Individuals infected with H. pylori possessing the CagA protein produce more reactive oxygen species (ROS) and show an increased risk of developing gastric cancer. Sirtuins (SIRTs) are nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases and mitochondrial SIRT3 is known to be a tumor suppressor via its ability to suppress ROS and hypoxia inducible factor 1α (HIF-1α). However, it is unclear whether increased ROS production by H. pylori is regulated by SIRT3 followed by HIF-1α regulation and whether intracellular CagA acts as a regulator thereof. In this study, we investigated correlations among SIRT3, ROS, and HIF-1α in H. pylori-infected gastric epithelial cells. We observed that SIRT3-deficient AGS cells induce HIF-1α protein stabilization and augmented transcriptional activity under hypoxic conditions. In CagA+ H. pylori infected cells, CagA protein localized to mitochondria where it subsequently suppressed SIRT3 proteins. CagA+ H. pylori infection also increased HIF-1α activity through the ROS production induced by the downregulated SIRT3 activity, which is similar to the hypoxic condition in gastric epithelial cells. In contrast, overexpression of SIRT3 inhibited the HIF-1α protein stabilization and attenuated the increase in HIF-1α transcriptional activity under hypoxic conditions. Moreover, CagA+ H. pylori attenuated HIF-1α stability and decreased transcriptional activity in SIRT3-overexpressing gastric epithelial cells. Taken together, these findings provide valuable insights into the potential role of SIRT3 in CagA+ H. pylori-mediated gastric carcinogenesis and a possible target for cancer prevention via inhibition of HIF-1α.

Synergistic anti-tumor activity of Nimotuzumab in combination with Trastuzumab in HER2-positive breast cancer

Breast cancer is characterized with poor prognosis and high recurrence. HER2 is highly expressed in breast cancer and is a target for cancer therapy and prevention. Here, we investigated the anti-tumor activity of the combination of an HER2 inhibitor, trastuzumab with an EGFR-inhibitor, nimotuzumab in HER2-overexpressing breast cancer. Our data showed that a greater anti-tumor activity from the combination of trastuzumab and nimotuzumab than any alone usage of above antibody both in vitro and in vivo. Based on the combination index value, our data demonstrated that nimotuzumab synergistically enhanced trastuzumab-induced cell growth inhibition. Furthermore, we investigated the possible mechanism of this synergistic efficacy induced by trastuzumab plus nimotuzumab. Data showed that the combination was more potent in reducing the phosphorylation of HER2 and ERK1/2. We also found that the synergistic inhibition was partly attributed to the ROS generation and repression of NRF2 pathway that is known to promote cell growth. These results support the clinical development of this two-drug regimen for the treatment of HER2-amplified breast cancer.

LTA4H regulates cell cycle and skin carcinogenesis.

Leukotriene A4 hydrolase (LTA4H), a bifunctional zinc metallo-enzyme, is reportedly overexpressed in several human cancers. Our group has focused on LTA4H as a potential target for cancer prevention and/or therapy. In the present study, we report that LTA4H is a key regulator of cell cycle at the G0/G1 phase acting by negatively regulating p27 expression in skin cancer. We found that LTA4H is overexpressed in human skin cancer tissue. Knocking out LTA4H significantly reduced skin cancer development in the 7,12-dimethylbenz(a)anthracene (DMBA)-initiated/12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted two-stage skin cancer mouse model. LTA4H depletion dramatically decreased anchorage-dependent and -independent skin cancer cell growth by inducing cell cycle arrest at the G0/G1 phase. Moreover, our findings showed that depletion of LTA4H enhanced p27 protein stability, which was associated with decreased phosphorylation of CDK2 at Thr160 and inhibition of the CDK2/cyclin E complex, resulting in down-regulated p27 ubiquitination. These findings indicate that LTA4H is critical for skin carcinogenesis and is an important mediator of cell cycle and the data begin to clarify the mechanisms of LTA4H's role in cancer development.

Anti-tumor effects of a ‘human & mouse cross-reactive’ anti-ADAM17 antibody in a pancreatic cancer model in vivo

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of tumor amongst all human cancers due to late diagnosis and resistant to treatment with chemotherapy and radiation. Preclinical and clinical studies have revealed that ErbB family for example epidermal growth factor receptor (EGFR) is a validated molecular target for pancreatic cancer prevention and therapy. The ErbB signaling cascade is regulated by a member of the ADAM (a disintegrin and metalloprotease) family, namely ADAM17, by enzymatic cleavage of precursor ligands into soluble cytokines and growth factors. Mouse genetic studies have demonstrated that ADAM17 is required for PDAC development. In this study, we evaluated the anti-tumor effects of A9(B8) IgG – the first specific ‘human and mouse cross-reactive’ ADAM17 inhibitory antibody on pancreatic malignant transformation. We found that inhibition of ADAM17 with A9(B8) IgG efficiently suppressed the shedding of ADAM17 substrates both in vivo and in vitro. Furthermore, we demonstrated that administration of A9(B8) IgG significantly suppressed motility in human pancreatic cancer cells and also significantly delayed tumorigenesis in the Pdx1Cre;KrasG12D;Trp53fl/+PDAC mouse model. Inhibition of ADAM17 with A9(B8) IgG particularly affected the progression of pre-invasive pancreatic lesions to advanced PDAC in mice. Taken together, the preclinical data presented here will provide a starting point for clinical applications of ADAM17 targeted therapy.

The effect of Autophagy in Regulation of ROS, Mitochondria damage, Aging, Inflammation and Metabolic control and Protects against Genome Instability and Necrosis as a Potential target in Cancer and Autoimmunity Treatment and Prevention

The effect of Autophagy in Regulation of ROS, Mitochondria damage, Aging, Inflammation and Metabolic control and Protects against Genome Instability and Necrosis as a Potential target in Cancer and Autoimmunity Treatment and Prevention