Ending of the COVID-19 Related Public and National Health Emergency Declarations: Implications for Medically Underserved Populations in Tennessee

The Biden administration decided to end the COVID-19 National and Public Health emergencies on May 11, 2023. These emergency declarations were established by the Trump Administration in early 2020. Under the COVID-19 emergency declarations, US citizens were provided with COVID-19 testing, vaccines, and treatments at little or no cost. The declarations allowed the federal government the option of waiving and or modifying government programs such Medicare, Medicaid. The emergency declarations were directly tied to other COVID-19 related provisions that have also expired that includes Economic Security (CARES) Act, the American Rescue Plan Act (ARPA), the Families First Coronavirus Response Act (FFCRA), the Coronavirus Aid, Relief, and the Inflation Reduction Act (IRA), the Consolidated Appropriations Act, 2023 (CAA). In addition, there were other federal and state emergency programs that were provided and too numerous to report here. At the time of this writing, the state of Tennessee continues to have moderate and sporadic spikes in COVID-19 cases and hospitalizations. Tennessee has higher than the national average of uninsured and underinsured people in the US. In Tennessee, more than 600,000 people are uninsured or underinsured in 2023 according to a study by the Kaiser Family Foundation. The ending of the PHE greatly impact coverage, cost, and access to COVID related services that will disproportionately affect the uninsured and medically underserved populations in Tennessee, the south in general, and throughout the US. Medically underserved populations are those groups with disparities in primary care, living in poverty, older, or having higher than expected infant mortality.

Spatiotemporal genomic profiling of intestinal metaplasia reveals clonal dynamics of gastric cancer progression

Intestinal metaplasia (IM) is a pre-malignant condition of the gastric mucosa associated with increased gastric cancer (GC) risk. Analyzing 1,256 gastric samples (1,152 IMs) across 692 subjects from a prospective 10-year study, we identify 26 IM driver genes in diverse pathways including chromatin regulation (ARID1A) and intestinal homeostasis (SOX9). Single-cell and spatial profiles highlight changes in tissue ecology and IM lineage heterogeneity, including an intestinal stem-cell dominant cellular compartment linked to early malignancy. Expanded transcriptome profiling reveals expression-based molecular subtypes of IM associated with incomplete histology, antral/intestinal cell types, ARID1A mutations, inflammation, and microbial communities normally associated with the healthy oral tract. We demonstrate that combined clinical-genomic models outperform clinical-only models in predicting IMs likely to transform to GC. By highlighting strategies for accurately identifying IM patients at high GC risk and a role for microbial dysbiosis in IM progression, our results raise opportunities for GC precision prevention and interception.

Kinesin Family Member B18 Is Related to Gastric Mucin Phenotype and Contributes to Gastric Cancer Progression by Regulating Epithelial-Mesenchymal Transition

INTRODUCTION

Gastric cancer (GC) remains a common health concern worldwide and is the third leading cause of death in Japan. It can be broadly classified into gastric and intestinal mucin phenotypes using immunohistochemistry. We previously reported numerous associations of kinesin family member (KIF) genes and mucin phenotypes with GC. However, no previous studies have reported on the importance of KIF18B in GC using immunostaining. Thus, in this study, we investigated the expression and functions of KIF18B, which is highly expressed in gastric mucin phenotype GC.

METHODS

We performed RNA-seq of gastric and intestinal mucin type GCs, and clinicopathological studies of the KIF18B we found were performed using 96 GC cases. We also performed functional analysis using GC-derived cell lines.

RESULT

RNA-seq showed the upregulation of matrisome-associated genes in gastric mucin phenotype GC and a high expression of KIF18B. KIF18B was detected in 52 of the 96 GC cases (54%) through immunohistochemistry. Low KIF18B expression was significantly associated with poor overall survival (p < 0.01). Other molecules that were significantly associated with KIF18B were MUC5AC and claudin 18; these were also significantly associated with the gastric mucin phenotype. KIF18B small interfering RNA (siRNA)-transfected GC cells showed greater growth and spheroid colony formation than the negative control siRNA-transfected cells. Furthermore, expression of snail family transcriptional repressor 1 and cadherin 2 was significantly increased and that of cadherin 1 was significantly decreased in KIF18B siRNA-transfected GC cells.

CONCLUSION

These findings not only suggest that KIF18B may be a useful prognostic marker, but also provide insight into the pathogenesis of the GC phenotype.

Comprehensive molecular phenotyping of ARID1A-deficient gastric cancer reveals pervasive epigenomic reprogramming and therapeutic opportunities

OBJECTIVE

Gastric cancer (GC) is a leading cause of cancer mortality, with ARID1A being the second most frequently mutated driver gene in GC. We sought to decipher ARID1A-specific GC regulatory networks and examine therapeutic vulnerabilities arising from ARID1A loss.

DESIGN

Genomic profiling of GC patients including a Singapore cohort (>200 patients) was performed to derive mutational signatures of ARID1A inactivation across molecular subtypes. Single-cell transcriptomic profiles of ARID1A-mutated GCs were analysed to examine tumour microenvironmental changes arising from ARID1A loss. Genome-wide ARID1A binding and chromatin profiles (H3K27ac, H3K4me3, H3K4me1, ATAC-seq) were generated to identify gastric-specific epigenetic landscapes regulated by ARID1A. Distinct cancer hallmarks of ARID1A-mutated GCs were converged at the genomic, single-cell and epigenomic level, and targeted by pharmacological inhibition.

RESULTS

We observed prevalent ARID1A inactivation across GC molecular subtypes, with distinct mutational signatures and linked to a NFKB-driven proinflammatory tumour microenvironment. ARID1A-depletion caused loss of H3K27ac activation signals at ARID1A-occupied distal enhancers, but unexpectedly gain of H3K27ac at ARID1A-occupied promoters in genes such as NFKB1 and NFKB2. Promoter activation in ARID1A-mutated GCs was associated with enhanced gene expression, increased BRD4 binding, and reduced HDAC1 and CTCF occupancy. Combined targeting of promoter activation and tumour inflammation via bromodomain and NFKB inhibitors confirmed therapeutic synergy specific to ARID1A-genomic status.

CONCLUSION

Our results suggest a therapeutic strategy for ARID1A-mutated GCs targeting both tumour-intrinsic (BRD4-assocatiated promoter activation) and extrinsic (NFKB immunomodulation) cancer phenotypes.

COVID-19 Vaccine Hesitancy and Uptake among Minority Populations in Tennessee

COVID-19 vaccine hesitancy and uptake among Southern states in the US has been problematic throughout the pandemic. To characterize COVID-19 vaccine hesitancy and uptake among medically underserved communities in Tennessee. We surveyed 1482 individuals targeting minority communities in Tennessee from 2 October 2021 to 22 June 2022. Participants who indicated that they did not plan to receive or were unsure whether to receive the COVID-19 vaccine were considered vaccine-hesitant. Among participants, 79% had been vaccinated, with roughly 5.4% not likely at all to be vaccinated in the next three months from the date that the survey was conducted. When focusing particularly on Black/AA people and white people, our survey results revealed a significant association between race (Black/AA, white, or people of mixed Black/white ancestry) and vaccination status (vaccinated or unvaccinated) (p-value = 0.013). Approximately 79.1% of all participants received at least one dose of a COVID-19 vaccine. Individuals who were concerned with personal/family/community safety and/or wanted a return to normalcy were less likely to be hesitant. The study found that the major reasons cited for refusing the COVID-19 vaccines were distrust in vaccine safety, concerns about side effects, fear of needles, and vaccine efficacy.

The Rare Case of Esophageal Cancer Presenting With Hematemesis in a 29-Year-Old Adult

Esophageal cancer is a disease with high mortality. This is mainly due to late presentations with nonspecific symptoms. Despite advances in surgery and chemoradiotherapy, it is the eighth most common cancer but the sixth deadliest. It is reportedly common in older patients but rare in young ones. In this case report, we present a 29-year-old male patient with no prior medical condition who presented with hematemesis to the emergency unit and was found to have esophageal cancer with the biopsy. Not only is esophageal cancer rare in young adults, but hematemesis is a rare symptom in esophageal cancer patients.

Vaccine Confidence and Uptake of the Omicron Bivalent Booster in Tennessee: Implications for Vulnerable Populations

The COVID-19 Omicron variant and its subvariants are now the dominant variants circulating in the US. Therefore, the original COVID-19 vaccine cannot offer full protection. Instead, vaccines that target the spike proteins of the Omicron variants are warranted. Hence, the FDA recommended the development of a bivalent booster. Unfortunately, despite the safety and immunogenicity of the Omicron bivalent boosters from Pfizer and Moderna, uptake in the US has been poor. At this time, only 15.8% of individuals in the US aged five and older have received the Omicron bivalent booster (OBB). The rate is 18% for those aged 18 and older. Poor vaccine confidence and booster uptake are often fueled by misinformation and vaccine fatigue. These result in more problems associated with vaccine hesitancy, which are particular prevalent in Southern states in the US. In Tennessee, the OBB vaccination rate for eligible recipients is only 5.88% at time of writing (16 February 2023). In this review, we discuss (1) the rationale for developing the OBBs; (2) the efficacy and safety of the bivalent boosters; (3) the adverse events associated with these boosters; (4) vaccine hesitancy associated with the OBBs uptake in Tennessee; (5) implications for vulnerable populations, disparities in uptake of OBBs in Tennessee, and strategies to improve vaccine confidence and OBB uptake. In support of public health, it is essential that we continue to provide education, awareness, and vaccine access to the vulnerable and medically underserved populations in Tennessee. Receiving the OBBs is the most effective method to date of protecting the public against severe COVID disease, hospitalization, and death.

The COVID-19 Vaccine and Pregnant Minority Women in the US: Implications for Improving Vaccine Confidence and Uptake

The American College of Obstetricians and Gynecologists (AGOG) recommends the FDA-approved Pfizer and Moderna mRNA COVID-19 vaccines and boosters for all eligible pregnant women in the US. However, COVID-19 vaccine confidence and uptake among pregnant minority women have been poor. While the underlying reasons are unclear, they are likely to be associated with myths and misinformation about the vaccines. Direct and indirect factors that deter minority mothers in the US from receiving the mRNA COVID-19 vaccines require further investigation. Here, we examine the historical perspectives on vaccinations during pregnancy. We will examine the following aspects: (1) the influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccinations during pregnancy; (2) the exclusion of pregnant and lactating women from COVID-19 vaccine trials; (3) COVID-19 vaccine safety during pregnancy, obstetric complications associated with symptomatic COVID-19 during pregnancy, COVID-19 vaccine hesitancy among pregnant minority women, and racial disparities experienced by pregnant minority women due to the COVID-19 pandemic as well as their potential impact on pregnancy care; and (4) strategies to improve COVID-19 vaccine confidence and uptake among pregnant minority women in the US. COVID-19 vaccine hesitancy among minority mothers can be mitigated by community engagement efforts that focus on COVID-19 vaccine education, awareness campaigns by trusted entities, and COVID-19-appropriate perinatal counseling aimed to improve COVID-19 vaccine confidence and uptake.

Circ_CEA promotes the interaction between the p53 and cyclin-dependent kinases 1 as a scaffold to inhibit the apoptosis of gastric cancer

Circular RNAs (circRNAs) have been reported to play essential roles in tumorigenesis and progression. This study aimed to identify dysregulated circRNAs in gastric cancer (GC) and investigate the functions and underlying mechanism of these circRNAs in GC development. Here, we identify circ_CEA, a circRNA derived from the back-splicing of CEA cell adhesion molecule 5 (CEA) gene, as a novel oncogenic driver of GC. Circ_CEA is significantly upregulated in GC tissues and cell lines. Circ_CEA knockdown suppresses GC progression, and enhances stress-induced apoptosis in vitro and in vivo. Mechanistically, circ_CEA interacts with p53 and cyclin-dependent kinases 1 (CDK1) proteins. It serves as a scaffold to enhance the association between p53 and CDK1. As a result, circ_CEA promotes CDK1-mediated p53 phosphorylation at Ser315, then decreases p53 nuclear retention and suppresses its activity, leading to the downregulation of p53 target genes associated with apoptosis. These findings suggest that circ_CEA protects GC cells from stress-induced apoptosis, via acting as a protein scaffold and interacting with p53 and CDK1 proteins. Combinational therapy of targeting circ_CEA and chemo-drug caused more cell apoptosis, decreased tumor volume and alleviated side effect induced by chemo-drug. Therefore, targeting circ_CEA might present a novel treatment strategy for GC.

Vimentin binds to a novel tumor suppressor protein, GSPT1-238aa, encoded by circGSPT1 with a selective encoding priority to halt autophagy in gastric carcinoma

Circular RNAs (circRNAs) are covalently closed, endogenous molecules that are widespread in eukaryotes. Recent evidence indicates that circRNAs play important roles in carcinogenesis. Several circRNAs have been reported to comprise translatable RNA; however, whether circRNAs encode functional proteins remains unknown. In our study, circRNA sequencing was carried out using five pathologically diagnosed gastric carcinoma (GC) samples and their paired adjacent normal tissues, we characterized the circRNA GSPT1 (circGSPT1), which is expressed at low levels in GC. Antibody detections, and mass spectrometry were used to validate active circRNA translation. The spanning junction open reading frame in circGSPT1, driven by an internal ribosome entry site (IRES), encodes a functional peptide, termed GSPT1-238aa. Interestingly, GSPT1-238aa tends to select the start codon used to initiate translation. This is the first finding of selective translation driven by IRES. CircGSPT1 and GSPT1-238aa halted the proliferation, migration, and invasion in GC cells in vitro. We also confirmed that the vimentin/Beclin1/14-3-3 complex interacts with GSPT1-238aa and modulates autophagy via the PI3K/AKT/mTOR signaling pathway in GC cells. Our study reveals that GSPT1-238aa, a novel protein encoded by circGSPT1, halts GC tumorigenesis. We also provide insights into the function and underlying molecular mechanisms of GSPT1-238aa in GC and suggest that this protein represents a novel target for GC treatment.

Breakthrough COVID-19 Infections in the US: Implications for Prolonging the Pandemic

The incidence of COVID-19 breakthrough infections-an infection that occurs after you have been vaccinated-has increased in frequency since the Delta and now Omicron variants of the SARS-CoV-2 coronavirus have become the dominant strains transmitted in the United States (US). Evidence suggests that individuals with breakthrough infections, though rare and expected, may readily transmit COVID-19 to unvaccinated populations, posing a continuing threat to the unvaccinated. Here, we examine factors contributing to breakthrough infections including a poor immune response to the vaccines due to the fact of advanced age and underlying comorbidities, the natural waning of immune protection from the vaccines over time, and viral variants that escape existing immune protection from the vaccines. The rise in breakthrough infections in the US and how they contribute to new infections, specifically among the unvaccinated and individuals with compromised immune systems, will create the need for additional booster vaccinations or development of modified vaccines that directly target current variants circulating among the general population. The need to expedite vaccination among the more than 49.8 million unvaccinated eligible people in the US is critical.

A novel protein AXIN1-295aa encoded by circAXIN1 activates the Wnt/β-catenin signaling pathway to promote gastric cancer progression

BACKGROUND

Circular RNA (circRNA), a subclass of non-coding RNA, plays a critical role in cancer tumorigenesis and metastasis. It has been suggested that circRNA acts as a microRNA sponge or a scaffold to interact with protein complexes; however, its full range of functions remains elusive. Recently, some circRNAs have been found to have coding potential.

METHODS

To investigate the role of circRNAs in gastric cancer (GC), parallel sequencing was performed using five paired GC samples. Differentially expressed circAXIN1 was proposed to encode a novel protein. FLAG-tagged circRNA overexpression plasmid construction, immunoblotting, mass spectrometry, and luciferase reporter analyses were applied to confirm the coding potential of circAXIN1. Gain- and loss-of-function studies were conducted to study the oncogenic role of circAXIN1 and AXIN1-295aa on the proliferation, migration, invasion, and metastasis of GC cells in vitro and in vivo. The competitive interaction between AXIN1-295aa and adenomatous polyposis coli (APC) was investigated by immunoprecipitation analyses. Wnt signaling activity was observed using a Top/Fopflash assay, real-time quantitative RT-PCR, immunoblotting, immunofluorescence staining, and chromatin immunoprecipitation.

RESULTS

CircAXIN1 is highly expressed in GC tissues compared with its expression in paired adjacent normal gastric tissues. CircAXIN1 encodes a 295 amino acid (aa) novel protein, which was named AXIN1-295aa. CircAXIN1 overexpression enhances the cell proliferation, migration, and invasion of GC cells, while the knockdown of circAXIN1 inhibits the malignant behaviors of GC cells in vitro and in vivo. Mechanistically, AXIN1-295aa competitively interacts with APC, leading to dysfunction of the "destruction complex" of the Wnt pathway. Released β-catenin translocates to the nucleus and binds to the TCF consensus site on the promoter, inducing downstream gene expression.

CONCLUSION

CircAXIN1 encodes a novel protein, AXIN1-295aa. AXIN1-295aa functions as an oncogenic protein, activating the Wnt signaling pathway to promote GC tumorigenesis and progression, suggesting a potential therapeutic target for GC.

MiRNA-20b/SUFU/Wnt axis accelerates gastric cancer cell proliferation, migration and EMT

Previous research has found that miRNA-20b is highly expressed in gastric cancer (GC), however, its function and underlying mechanism are not clear. Wnt signaling pathway, implicated in tumorigeneisis, is activated in more than 30% of GC. We would like to characterize the biological behavior of miRNA-20b in terms of modulating Wnt/β-catenin signaling and EMT. We showed that miRNA-20b inhibitors suppressed Topflash/Fopflash dependent luciferase activity and the β-catenin nuclear translocation, resulting in inhibition of Wnt pathway activity and EMT. SUFU, negatively regulating Wnt and Hedgehog signaling pathway, was proved to be targeted by miRNA-20b. Moreover, additional knockdown of SUFU alleviated the inhibitory effect on Wnt pathway activity, EMT, cell proliferation/migration and colony formation caused by miRNA-20b inhibition. In summary, miRNA-20b is an oncogenic miRNA and promoted cell proliferation, migration and EMT in GC partially by activating Wnt pathway via targeting SUFU.

Dual activation of Hedgehog and Wnt/β-catenin signaling pathway caused by downregulation of SUFU targeted by miRNA-150 in human gastric cancer

Mounting evidence has shown that miRNA-150 expression is upregulated in gastric cancer (GC) and is associated with gastric carcinogenesis, but the underlying oncogenic mechanism remains elusive. Here, we discovered that miRNA-150 targets the tumor suppressor SUFU to promote cell proliferation, migration, and the epithelial-mesenchymal transition (EMT) via the dual activation of Hedgehog (Hh) and Wnt signaling. MiRNA-150 was highly expressed in GC tissues and cell lines, and the level of this miRNA was negatively related to that of SUFU. In addition, both the miRNA-150 and SUFU levels were associated with tumor differentiation. Furthermore, miRNA-150 activated GC cell proliferation and migration in vitro. We found that miRNA-150 inhibitors repressed not only Wnt signaling by promoting cytoplasmic β-catenin localization, but also repressed Hh signaling and EMT. MiRNA-150 inhibition also resulted in significant tumor volume reductions in vivo, suggesting the potential application of miRNA-150 inhibitors in GC therapy. The expression of genes downstream of Hh and Wnt signaling was also reduced in tumors treated with miRNA-150 inhibitors. Notably, anti-SUFU siRNAs rescued the inhibitory effects of miRNA-150 inhibitors on Wnt signaling, Hh activation, EMT, cell proliferation, cell migration, and colony formation. Taken together, these findings indicate that miRNA-150 is oncogenic and promotes GC cell proliferation, migration, and EMT by activating Wnt and Hh signaling via the suppression of SUFU expression.

Tumor-specific overexpression of histone gene, H3C14 in gastric cancer is mediated through EGFR-FOXC1 axis

Incorporation of different H3 histone isoforms/variants have been reported to differentially regulate gene expression via alteration in chromatin organization during diverse cellular processes. However, the differential expression of highly conserved histone H3.2 genes, H3C14 and H3C13 in human cancer has not been delineated. In this study, we investigated the expression of H3.2 genes in primary human gastric, brain, breast, colon, liver, and head and neck cancer tissues and tumor cell lines. The data showed overexpression of H3.2 transcripts in tumor samples and cell lines with respect to normal counterparts. Furthermore, TCGA data of individual and TCGA PANCAN cohort also showed significant up-regulation of H3.2 genes. Further, overexpressed H3C14 gene coding for H3.2 protein was regulated by FOXC1 transcription factor and G4-cassette in gastric cancer cell lines. Elevated expression of FOXC1 protein and transcripts were also observed in human gastric cancer samples and cell lines. Further, FOXC1 protein was predominantly localized in the nuclei of neoplastic gastric cells compared to normal counterpart. In continuation, studies with EGF induction, FOXC1 knockdown, and ChIP-qPCR for the first time identified a novel axis, EGFR-FOXC1-H3C14 for regulation of H3C14 gene overexpression in gastric cancer. Therefore, the changes the epigenomic landscape due to incorporation of differential expression H3 variant contributes to change in gene expression pattern and thereby contributing to pathogenesis of cancer.

Histone methyltransferase SET8 is regulated by miR-192/215 and induces oncogene-induced senescence via p53-dependent DNA damage in human gastric carcinoma cells

Gastric cancer (GC) is the most common cancer throughout the world. Despite advances of the treatments, detailed oncogenic mechanisms are largely unknown. In our previous study, we investigated microRNA (miR) expression profiles in human GC using miR microarrays. We found miR-192/215 were upregulated in GC tissues. Then gene microarray was implemented to discover the targets of miR-192/215. We compared the expression profile of BGC823 cells transfected with miR-192/215 inhibitors, and HFE145 cells transfected with miR-192/-215 mimics, respectively. SET8 was identified as a proposed target based on the expression change of more than twofold. SET8 belongs to the SET domain-containing methyltransferase family and specifically catalyzes monomethylation of H4K20me. It is involved in diverse functions in tumorigenesis and metastasis. Therefore, we focused on the contributions of miR-192/215/SET8 axis to the development of GC. In this study, we observe that functionally, SET8 regulated by miR-192/215 is involved in GC-related biological activities. SET8 is also found to trigger oncogene-induced senescence (OIS) in GC in vivo and in vitro, which is dependent on the DDR (DNA damage response) and p53. Our findings reveal that SET8 functions as a negative regulator of metastasis via the OIS-signaling pathway. Taken together, we investigated the functional significance, molecular mechanisms, and clinical impact of miR-192/215/SET8/p53 in GC.

SUFU mediates EMT and Wnt/β-catenin signaling pathway activation promoted by miRNA-324-5p in human gastric cancer

The poor prognosis of late gastric carcinomas (GC) underscores the necessity to identify novel biomarkers for earlier diagnosis and effective therapeutic targets. MiRNA-324-5p has been shown to be over-expressed in GC, however the biological function of miRNA-324-5p implicated in gastric cancer and its downstream targets were not well understood. Wnt/β-catenin signaling pathway is aberrantly regulated in GC. We sought to explore if miRNA-324-5p promotes oncogenesis through modulating Wnt signaling and EMT. MiRNA-324-5p is highly expressed in GC based on qRT-PCR and TCGA data. In addition, in vitro cell proliferation, cell migration assays and in vivo animal exenograft were executed to show that miRNA-324-5p is an oncogenic miRNA in GC. MiRNA-324-5p activates Wnt signaling and induces EMT in GC. Further, SUFU was identified as a target of miRNA-324-5p confirmed by western blotting and luciferase assays. Spearson analysis and TCGA data indicate that the expression of SUFU is negatively associated with the expression of miRNA-324-5p. Rescue experiments were performed to determine if SUFU mediates the Wnt activation, EMT and oncogenic function of miRNA-324-5p. MiRNA-324-5p inhibitors plus SUFU siRNAs rescue partially the inhibitory effect on Wnt signaling and EMT caused by miRNA-324-5p inhibitors. Finally, the suppression of cell proliferation, migration, and colony formation ability induced by miRNA-324-5p inhibitors is alleviated by addition of SUFU siRNAs. In summary, miRNA-324-5p is overexpressed in vivo and exerts cell growth and migration-promoting effects through activating Wnt signaling and EMT by targeting SUFU in GC. It represents a potential miRNA with an oncogenic role in human gastric cancer.

miRNA-192 and -215 activate Wnt/β-catenin signaling pathway in gastric cancer via APC

Although great progress has been made in surgical techniques, traditional radiotherapy, and chemotherapy, gastric cancer (GC) is still the most common malignant tumor and has a high mortality, which highlights the importance of novel diagnostic markers. Emerging studies suggest that different microRNAs (miRNAs) are involved in tumorigenesis of GC. In this study, we found that miRNA-192 and -215 are significantly upregulated in GC and promote cell proliferation and migration. Adenomatous polyposis coli (APC), a well-known negative regulator in Wnt signaling, has been proved to be a target of miRNA-192 and -215. Inhibition of miRNA-192 or -215 reduced the Topflash activities and repressed the expression of Wnt signaling pathway proteins, while APC small interfering RNAs reversed the inhibitory effects, suggesting that miRNA-192 and -215 activate Wnt signaling via APC. In addition, APC mediates the cell proliferation and migration regulated by miRNA-192 and -215. Furthermore, APC is downregulated in GC tissues and negatively correlated with the expression of miRNA-192 and -215. In summary, miRNA-192 and -215 target APC and function as oncogenic miRNAs by activating Wnt signaling in GC, revealing to be potential therapeutic targets.

HNF4α pathway mapping identifies wild-type IDH1 as a targetable metabolic node in gastric cancer

OBJECTIVE

Gastric cancer (GC) is a leading cause of cancer mortality. Previous studies have shown that hepatocyte nuclear factor-4α (HNF4α) is specifically overexpressed in GC and functionally required for GC development. In this study, we investigated, on a genome-wide scale, target genes of HNF4α and oncogenic pathways driven by HNF4α and HNF4α target genes.

DESIGN

We performed HNF4α chromatin immunoprecipitation followed by sequencing across multiple GC cell lines, integrating HNF4α occupancy data with (epi)genomic and transcriptome data of primary GCs to define HNF4α target genes of in vitro and in vivo relevance. To investigate mechanistic roles of HNF4α and HNF4α targets, we performed cancer metabolic measurements, drug treatments and functional assays including murine xenograft experiments.

RESULTS

Gene expression analysis across 19 tumour types revealed HNF4α to be specifically upregulated in GCs. Unbiased pathway analysis revealed organic acid metabolism as the top HNF4α-regulated pathway, orthogonally supported by metabolomic analysis. Isocitrate dehydrogenase 1 (IDH1) emerged as a convergent HNF4α direct target gene regulating GC metabolism. We show that wild-type IDH1 is essential for GC cell survival, and that certain GC cells can be targeted by IDH1 inhibitors.

CONCLUSIONS

Our results highlight a role for HNF4α in sustaining GC oncogenic metabolism, through the regulation of IDH1. Drugs targeting wild-type IDH1 may thus have clinical utility in GCs exhibiting HNF4α overexpression, expanding the role of IDH1 in cancer beyond IDH1/2 mutated malignancies.

Inhibition of miR‑194 suppresses the Wnt/β‑catenin signalling pathway in gastric cancer

A mounting body of evidence has revealed that microRNAs (miRs) serve pivotal roles in various developmental processes, and in tumourigenesis, by binding to target genes and subsequently regulating gene expression. Continued activation of the Wnt/β-catenin signalling is positively associated with human malignancy. In addition, miR-194 dysregulation has been implicated in gastric cancer (GC); however, the molecular mechanisms underlying the effects of miR-194 on GC carcinogenesis remain to be elucidated. The present study demonstrated that miR-194 was upregulated in GC tissues and SUFU negative regulator of Ηedgehog signaling (SUFU) was downregulated in GC cell lines. Subsequently, inhibition of miR-194 attenuated nuclear accumulation of β-catenin, which consequently blocked Wnt/β-catenin signalling. In addition, the cytoplasmic translocation of β-catenin induced by miR-194 inhibition was mediated by SUFU. Furthermore, genes associated with the Wnt/β-catenin signalling pathway were revealed to be downregulated following inhibition of the Wnt signalling pathway by miR-194 suppression. Finally, the results indicated that cell apoptosis was markedly increased in response to miR-194 inhibition, strongly suggesting the carcinogenic effects of miR-194 in GC. Taken together, these findings demonstrated that miR-194 may promote gastric carcinogenesis through activation of the Wnt/β-catenin signalling pathway, making it a potential therapeutic target for GC.

Clinicians' perspectives on and interest in participating in a clinical data research network across the Southeastern United States

BACKGROUND

Partnerships between clinicians and researchers could increase the generalizability of research findings and increase uptake of research results across populations. Yet engaging clinicians in research is challenging. Clinical Data Research Networks (CDRNs) provide access to a broad array of clinical data, patients, clinicians and health systems by building on existing health records (EHRs) to facilitate multi-site community engaged research (CEnR).

METHODS

A mixed-methods sequential explanatory design was employed. Sixty semi-structured interviews with clinicians from various disciplines and healthcare settings were conducted using five open-ended questions. Inductive content analysis was used to identify emerging themes in the data.

RESULTS

We identified the following emerging themes: 1) Research with relevance and benefits to clinics and provider's patient population; 2) Difficulties of engaging in research with existing patient care demands; 3) Clear and continuous two-way communication about research, coordinated with provider and clinic needs; 4) Tailored compensation approaches meet provider preferences; 5) Increasing clinician awareness about Clinical Data Research Networks (CDRNs).

CONCLUSION

Our interview study provides insight into community clinician perspectives on Clinical Data Research Networks, indicating motivations and challenges to research involvement including consequences of time spent on research participation, barriers to expanding research and meaningful involvement in research governance. Findings can be used to guide the development of strategies to better engage providers in research in clinical settings, which could ultimately improve patient outcomes.

YAP/TAZ Initiates Gastric Tumorigenesis via Upregulation of MYC

YAP and TAZ play oncogenic roles in various organs, but the role of YAP/TAZ in gastric cancer remains unclear. Here, we show that YAP/TAZ activation initiates gastric tumorigenesis in vivo and verify its significance in human gastric cancer. In mice, YAP/TAZ activation in the pyloric stem cell led to step-wise tumorigenesis. RNA sequencing identified MYC as a decisive target of YAP, which controls MYC at transcriptional and posttranscriptional levels. These mechanisms tightly regulated MYC in homeostatic conditions, but YAP activation altered this balance by impeding miRNA processing, causing a shift towards MYC upregulation. Pharmacologic inhibition of MYC suppressed YAP-dependent phenotypes in vitro and in vivo, verifying its functional role as a key mediator. Human gastric cancer samples also displayed a significant correlation between YAP and MYC. We reanalyzed human transcriptome data to verify enrichment of YAP signatures in a subpopulation of gastric cancers and found that our model closely reflected the molecular pattern of patients with high YAP activity. Overall, these results provide genetic evidence of YAP/TAZ as oncogenic initiators and drivers for gastric tumors with MYC as the key downstream mediator. These findings are also evident in human gastric cancer, emphasizing the significance of YAP/TAZ signaling in gastric carcinogenesis.Significance: YAP/TAZ activation initiates gastric carcinogenesis with MYC as the key downstream mediator. Cancer Res; 78(12); 3306-20. ©2018 AACR.

Histone isoform H2A1H promotes attainment of distinct physiological states by altering chromatin dynamics

Background

The distinct functional effects of the replication-dependent histone H2A isoforms have been demonstrated; however, the mechanistic basis of the non-redundancy remains unclear. Here, we have investigated the specific functional contribution of the histone H2A isoform H2A1H, which differs from another isoform H2A2A3 in the identity of only three amino acids.

Results

H2A1H exhibits varied expression levels in different normal tissues and human cancer cell lines (H2A1C in humans). It also promotes cell proliferation in a context-dependent manner when exogenously overexpressed. To uncover the molecular basis of the non-redundancy, equilibrium unfolding of recombinant H2A1H-H2B dimer was performed. We found that the M51L alteration at the H2A–H2B dimer interface decreases the temperature of melting of H2A1H-H2B by ~ 3 °C as compared to the H2A2A3-H2B dimer. This difference in the dimer stability is also reflected in the chromatin dynamics as H2A1H-containing nucleosomes are more stable owing to M51L and K99R substitutions. Molecular dynamic simulations suggest that these substitutions increase the number of hydrogen bonds and hydrophobic interactions of H2A1H, enabling it to form more stable nucleosomes.

Conclusion

We show that the M51L and K99R substitutions, besides altering the stability of histone–histone and histone–DNA complexes, have the most prominent effect on cell proliferation, suggesting that the nucleosome stability is intimately linked with the physiological effects observed. Our work provides insights into the molecular basis of the non-redundancy of the histone H2A isoforms that are being increasingly reported to be functionally important in varied physiological contexts.

Electronic supplementary material

The online version of this article (doi:10.1186/s13072-017-0155-z) contains supplementary material, which is available to authorized users.

SLC5A8 gene, a transporter of butyrate: a gut flora metabolite, is frequently methylated in African American colon adenomas

Background

Colon cancer is one of the leading causes of cancer related deaths. Its impact on African Americans (AAs) is higher than in the general population both in the incidence and mortality from the disease. Colon cancer aggressiveness in AAs as well as non-frequent check-ups and follow up in this population have been proposed as ways to explain the observed discrepancies. These facts made the detection of early carcinogenesis markers in this population a priority.

Materials and Methods

Here, we analyzed 50 colon adenomas from AA patients for both microsatellite instability (MSI) and the methylation status of SLC5A8 gene. This gene's product is involved in the transport of butyrate that has anti-proliferative properties through its effects on histone acetylation and gene expression. A proteomic analysis to check the expressed histones in adenoma and normal tissues was also performed.

Results

The analyzed samples displayed 82% (n = 41) methylation level of SLC5A8 gene in adenomas. The MSI-H (high) adenoma were about 18% (n = 9) while the rest were mostly MSS (microsatellite stable) with few MSI-L (Low). No association was found between SLC5A8 methylation and the MSI status. Also, there was no association between SLC5A8 methylation and the sex and age of the patients. However, there were more right sided adenomas with SLC5A8 methylation than the left sided ones. The proteomic analysis revealed distinct histone expression profiles between normal and adenoma tissues.

Conclusion

SLC5A8 is highly methylated in AA colon adenomas which points to its potential use as a marker for early detection. The MSI rate is similar to that found in colon cancer tumors in AAs. These findings suggest that both processes stem from the same epigenetic and genetic events occurring at an early stage in colon carcinogenesis in AAs.

Investigating the pathobiology of alcoholic pancreatitis

Alcohol abuse is one of the most common causes of pancreatitis. The risk of developing alcohol-induced pancreatitis is related to the amount and duration of drinking. However, only a small portion of heavy drinkers develop disease, indicating that other factors (genetic, environmental, or dietary) contribute to disease initiation. Epidemiologic studies suggest roles for cigarette smoking and dietary factors in the development of alcoholic pancreatitis. The mechanisms underlying alcoholic pancreatitis are starting to be understood. Studies from animal models reveal that alcohol sensitizes the pancreas to key pathobiologic processes that are involved in pancreatitis. Current studies are focussed on the mechanisms responsible for the sensitizing effect of alcohol; recent findings reveal disordering of key cellular organelles including endoplasmic reticulum, mitochondria, and lysosomes. As our understanding of alcohol's effects continue to advance to the level of molecular mechanisms, insights into potential therapeutic strategies will emerge providing opportunities for clinical benefit.

Abstract B48: Do the gut flora play a role in the high incidence of colon cancer in African Americans?

Colonic adenomatous polyps are common tumors occurring in 50% of Western populations with 10% risk of malignant progression. To date, the environmental exposures proposed to promote the development of colorectal cancer (CRC) have been primarily dietary agents. However, the local environment to which the colonic mucosa is exposed is created by the bacterial microbiota of the colon and their metabolic products that include toxins. African Americans are known to have a higher incidence of colon cancer than other groups.

We analyzed the gut flora from African Americans patients by both 16S rDNA sequencing and HIT (Human Intestinal Tract) Chip. Our findings reflected a high prevalence of Bacteroidetes and Clostridia groups with the Bacteroidetes slightly more represented in patients with colon polyps than healthy ones. While Bifidobacteria were not detected at all in all samples, Lactobacilliwere present at a very low frequency. Both bacteria are referred to as “good bacteria” and are generally associated with healthy colon. Helicobacter bacteria, associated with gastric cancer, were also detected in all analysed samples. Bacteroides fragilis and relatives were present in all samples at a high frequency. It is noteworthy that an enterotoxigenic Bacteroides fragilis have been found to trigger colon polyps formation in Min mice through a pSTAT3 pathway. A tissue microarray immunohistochemistry experiment on colon adenoma and matched normals revealed a strong expression of pSTAT3 both in colonic epithelial cells and in colonic immune cells in adenoma samples but not as much in normal ones. These findings highlight the presence of a possible ETBF-like induction mechanism in the analysed samples.

Enzyme immunoassay for the detection of antibodies against ETBF toxin would confirm such findings and a metagenomic analysis of the analysed samples would shed light on predominant bacterial functions in adenoma patients that might play a role in colon oncogenic transformation in this population.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):B48.

Abstract 3453: Phylogenetic fingerprinting of the fecal microbiota in colorectal cancer patients

Colonic adenomatous polyps are common tumors occurring in ∼50% of Western populations with ∼10% risk of malignant progression. To date, the environmental exposures proposed to promote the development of colorectal cancer (CRC) have been primarily dietary agents. However, the local environment to which the colonic mucosa is exposed is created by the bacterial microbiota of the colon and their metabolic products that include toxins. A member of the Bacteroidetes division, Bacteroides fragilis is a common human commensal, occupying a mucosal niche in the colon. One molecular class of B. fragilis, enterotoxigenic B. fragilis (ETBF) induces polyp formation in Min (multiple intestinal neopplasia) mice through a STAT3 pathway.

Here we analyzed fecal DNA for gut flora composition in African Americans (n=12) with colon adenoma. A 16S rDNA cloning/sequencing experiment revealed that patients with colon adenomas have a higher rate of Bacteroides bacteria than healthy ones. These data was further confirmed using a HITChip (Human Intestinal Tract Chip) where samples from adenoma patients tended to cluster together pointing to common bacterial profiles.

STAT3 induced in adenoma and tumor by IHC, indicating, signal activation perhaps through ETBF like bacteria.

In conclusion, High throughput and sequencing approaches may help to better detect gut flora components including Bacteroides fragilis that induces colorectal carcinogenesis. In addition, the STAT3 expression results would confirm possible ETBF involvement on colon cancer risk via activating STAT3 downstream factor and molecules that are known to play a key role in the regulation of epithelial proliferation

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 3453.

Abstract 2713: Helicobacter pylori increases the risk of colorectal polyps in African Americans

Background: H. Pylori infection have linked to colorectal polyps, mainly through hypergastrinemia and its trophic effect on colon mucosa. African Americans were under represented despite both common diseases are more prevalent in them.

Aim: The aim of this study was to investigate whether H. Pylori infection has a role in development of colorectal polyps in Africans Americans.

Methods: Retrospectively, Africans Americans (n=1262) greater than 40 years old who underwent bidirectional gastrointestinal endoscopy on the same day were enrolled. The pre-procedure indication and post-procedure diagnosis were recorded (n=1262). H. Pylori status was assessed by immunohistochemistry on gastric specimens. Colorectal polyps were confirmed by histological examination of biopsies from complete colonoscopy. Multivariable logistic regression was used to assess the independent risk factors of polyp occurrence.

Results: Colorectal polyps (regardless polyp pathology) were more prevalent in H. Pylori-infected subjects (43%; 160/368) compared to (34%; 302/894) uninfected subjects (OR=1.5; 95 %CI=1.2-1.9). Furthermore, there was a trend toward larger polyp size ≥ 1cm in H. Pylori positive patients (P=0.07). There was no difference in histopathology or location of polyps in regard to H. Pylori status. Among the participants, 21 (2%) were defined with baseline above average risk for colorectal polyps justifying colonoscopy and of those; the polyps were detected in 62% (OR; 95%CI=2.9; 1.2-7.1). Age and male gender were independent risk factors for colorectal polyps.

Conclusion: H. Pylori increases the risk of developing colorectal polyps and may increase the chances for having a larger size polyp in Africans Americans. These findings suggest that H. Pylori might have a role in the initiation and/or promotion of polyps. Further studies are needed to explore its mechanisms.

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 2713.

2Am-DNT induces cell death and apoptosis in human cells

During microbial or mammalian cell metabolism, TNT (2,4,6-tinitrotoluene) is reduced to 2Am-DNT (2-amino-4,6-dinitrotoluene), 4Am-DNT, or 2,4-diamino-NT (2,4-diaminonitrotoluelne) depending on the specific organism. The metabolite 2Am-DNT is the most common of the TBT biotransformation pathways in bacterial and fungal species studied to date. in the mammalian liver cells, TNT is metabolized to 2Am-DNT by the P450 enzyme system. Apoptosis is rapidly emerging as a relevant endpoint for detecting low-dose toxin exposure. We report in this study that 2Am-DNT treatment of mammalian cells causes cell death by apoptosis. Cell death was assayed by the Trypan Blue method. Apoptotic changes, such as DNA break down, were detected in treated cells by the production of a dark-brown DAB (diaminobenzidine) signal using the Fragel Klenow DNA fragment detection system, by immunohistochemical techniques with fluorescence microscopy, and by using a microplate reader for a single-stranded DNA binding assay. All of these results showed that 2am-DNT is toxic to mammalian cells and induces apoptosis.

Global histone H4 acetylation and HDAC2 expression in colon adenoma and carcinoma

Chromatin remodeling and activation of transcription are important aspects of gene regulation, but these often go awry in disease progression, including during colon cancer development. We investigated the status of global histone acetylation (by measuring H3, H4 acetylation of lysine residues, which also occur over large regions of chromatin including coding regions and non-promoter sequences) and expression of histone deacetylase 2 (HDAC2) in colorectal cancer (CRC) tissue microarrays using immunohistochemical staining. Specifically, HDAC2 and the acetylation of histones H4K12 and H3K18 were evaluated in 134 colonic adenomas, 55 moderate to well differentiated carcinomas, and 4 poorly differentiated carcinomas compared to matched normal tissue. In addition, the correlation between expression of these epigenetic biomarkers and various clinicopathological factors including, age, location, and stage of the disease were analyzed. HDAC2 nuclear expression was detected at high levels in 81.9%, 62.1%, and 53.1% of CRC, adenomas, and normal tissue, respectively (P = 0.002). The corresponding nuclear global expression levels in moderate to well differentiated tumors for H4K12 and H3K18 acetylation were increased while these levels were decreased in poorly differentiated tumors (P = 0.02). HDAC2 expression was correlated significantly with progression of adenoma to carcinoma (P = 0.002), with a discriminative power of 0.74, when comparing cancer and non-cancer cases. These results suggest HDAC2 expression is significantly associated with CRC progression.

A 50-year review of colorectal cancer in African Americans: implications for prevention and treatment

BACKGROUND

African-Americans (AA) have the highest rate of colorectal cancer (CRC) incidence and mortality in the US. CRC in AA is more advanced and right-sided. Although screening has been shown to reduce mortality from CRC in the general US population, AA continue to experience a disproportionately higher CRC death compared to other ethnic groups. This study aimed at assessing the trend of CRC in AA, focusing on the changing pattern of in situ tumors in this ethnic group and how observed trends may guide current and future preventive and treatment strategies.

MATERIALS AND METHODS

All pathologic reports from 1959 to 2006 in Howard University Hospital (n = 150,000) were reviewed manually. The pathology reports showing colorectal cancer were carefully reviewed and selected by a GI pathologist. Intraepithelial or intramucosal carcinomas were diagnosed as in situ carcinoma. Reviewed pathological information were entered into Microsoft Excel and checked for duplication and missing data. Differences in situ and advanced cancer by sex, histology, location, and years of diagnosis were assessed by Chi-square test.

RESULTS

A total of 1,753 CRC cases were diagnosed in this period. About 56% of the cases were female and 51% of the tumors were left-sided. Mean (SD) age was 66 (13) years. The frequency of in situ tumor was 5.8% in this period. There was no statistically significant difference between in situ and advance tumor by age, sex, and tumor location. The rate of in situ tumor peaked in the 1990s at 8.5% (P = 0.0001). We observed a decade-to-decade increasing rate of right-sided tumors, which started at 36% in the period 1959-1970 and peaked in the period of 2001-2006 at 60% (P = 0.0001).

CONCLUSIONS

The recent increasing number of advanced and right-sided tumor in our study is concordant with SEER data and has great importance in developing CRC prevention and treatment strategies for AA population.

Protective effect of Cox-2 allelic variants on risk of colorectal adenoma development in African Americans

BACKGROUND

Recent evidence indicates that single nucleotide polymorphisms (SNPs) in the Cox-2 gene may modulate the risk of colorectal adenoma development.

PATIENTS AND METHODS

We explored possible associations between Cox-2 polymorphisms and risk of adenoma development in an African American case-control study comprising 72 cases of advanced adenomas and 146 polyp-free controls. An exhaustive approach of genotyping 13 haplotype-tagging SNPs (ht SNPs) distributed over the entire COX-2 gene was used.

RESULTS

Statistically significant inverse associations were observed between the heterozygous genotypes at the 5229 G>T polymorphism in intron 5 [odds ratio (OR)=0.42; confidence interval (CI)=0.19-0.92; p=0.03] and at the 10935 A>G polymorphism in the 3' flanking region downstream from the poly A signals (OR=0.39; CI=0.18-0.83;p=0.01) and the risk for colorectal adenoma development.

CONCLUSION

The data from our pilot study suggest that allelic variants of the COX-2 gene significantly influence the risk of adenoma development in the African American population.

Legume intake and reduced colorectal adenoma risk in African-Americans

Colorectal adenomas are known precursors for colorectal cancer. Several studies have shown that dietary factors can influence adenoma formation and growth. This study was conducted using African-American men and women who were undergoing colonoscopies in order to examine the relationship between selected dietary factors and the risk for colon polyps. In a case-control design, 186 men and women with a mean of 58 years of age were studied. A multiple logistic regression model was used to adjust for potential confounding variables and to determine which factors influence colorectal adenoma risk. Study results revealed that consumption of legumes such as dried beans, split peas, or lentils was negatively associated with risk (OR = 0.19; 95% CI: 0.04-0.91). Legumes are a good source of dietary fiber and of phytochemical compounds that may play a role in reducing adenoma formation or growth, thereby decreasing the risk of colorectal cancer. Nurses working with African-Americans should encourage consumption of these foods to decrease this risk.

Frequency of nonalcoholic fatty liver disease and degree of hepatic steatosis in African-American patients

BACKGROUND

This retrospective study evaluates the degree and distribution of hepatic steatosis in predominantly African-American patients who had liver biopsies over a period of five years in our institution.

METHOD

A search in the pathology registry of Howard University Hospital was performed for the presence of fat in liver biopsies. Each biopsy was assessed.

RESULTS

Of the 320 liver biopsies that were reviewed, 61 were found to have steatosis. Fifty-six of the 61 patients were African-American. The mean body mass index in those African-American patients was found to be 30. Grade-1 steatosis was found in 16 patients, grade 2 in 22 patients, grade 3 in 14 patients and nine patients had grade-4 steatosis. Four patients fulfilled the criteria for the diagnosis of nonalcoholic fatty liver disease (NAFLD). All four patients had simple steatosis without any inflammation. The frequency of NAFLD in our study population was found to be <2%. Nonalcoholic steatohepatitis was not found in any of our study population. Dyslipidemia was found in all four patients with steatosis.

CONCLUSION

NAFLD has a low prevalence in African-American patients. Nonalcoholic steatohepatitis was not found in any of the African-American patients seen at our institution.

Ethanol feeding alters death signaling in the pancreas

OBJECTIVES

Alcohol abuse is a major cause of pancreatitis, which is associated with death of parenchymal cells. The goal of this study was to explore the effects of ethanol on cell death pathways in the pancreas.

METHODS

Adult male Wistar rats were fed with ethanol diets using the Lieber-DeCarli method. Caspase-8, caspase-3, and cathepsin B expression and activity in the pancreas of these animals as well as the signals that regulate their expression were studied using Western blot analysis and specific assays for biochemical enzyme activity.

RESULTS

In the pancreas from rats fed with ethanol, the protein expression and activity of caspase-8 decreased by 48% and 45%, respectively, and caspase-3 activity decreased by 39%. In contrast, cathepsin B protein expression and activity increased with ethanol feeding by 189% and 143%, respectively. Evaluation of the transcriptional regulatory system for caspase-8 and cathepsin B showed that the ethanol effects on these pathways were largely transcriptional.

CONCLUSIONS

Our findings show effects of ethanol on the expression of several signals involved in cell death in the pancreas through alteration of transcriptional regulators. The decrease in caspase expression and increase in cathepsin B expression indicate that ethanol feeding may prevent apoptosis and promote necrosis of pancreatic tissue with stresses that cause pancreatitis.

Antimicrobial resistance incidence and risk factors among Helicobacter pylori-infected persons, United States

Helicobacter pylori is the primary cause of peptic ulcer disease and an etiologic agent in the development of gastric cancer. H. pylori infection is curable with regimens of multiple antimicrobial agents, and antimicrobial resistance is a leading cause of treatment failure. The Helicobacter pylori Antimicrobial Resistance Monitoring Program (HARP) is a prospective, multicenter U.S. network that tracks national incidence rates of H. pylori antimicrobial resistance. Of 347 clinical H. pylori isolates collected from December 1998 through 2002, 101 (29.1%) were resistant to one antimicrobial agent, and 17 (5%) were resistant to two or more antimicrobial agents. Eighty-seven (25.1%) isolates were resistant to metronidazole, 45 (12.9%) to clarithromycin, and 3 (0.9%) to amoxicillin. On multivariate analysis, black race was the only significant risk factor (p < 0.01, hazard ratio 2.04) for infection with a resistant H. pylori strain. Formulating pretreatment screening strategies or providing alternative therapeutic regimens for high-risk populations may be important for future clinical practice.

Effects of 2-amino-4,6-dinitrotoluene on p53 tumor suppressor gene expression

2-Amino-4,6-dinitrotoluene (2-Am-DNT) and its isomers are the most common metabolites of 2,4,6-trinitrotoluene (TNT). It is desirable to know the toxicity of this metabolite particularly because of its role in carcinogenicity and because it could contaminate drinking water. We used MCF-7 human breast cancer cells which have p53 tumor suppressor gene in wild type form in both the loci. Immunoblotting with p53 antibody showed enhanced p53 level in treated cells compared to untreated control cells. Similarly, p53 DNA-protein binding assays (gel-shift) showed accumulation of p53 protein in treated cells. This is the first report which shows p53 accumulation in 2-Am-DNT treated cells providing evidence of potential carcinogenic effects of 2-Am-DNT.

Enrollment of African Americans Onto Clinical Treatment Trials: Study Design Barriers

Purpose

African Americans have the highest cancer mortality rates and poorest survival and are more often uninsured and underinsured compared with other ethnic groups. Minority participation in clinical trials has traditionally been low, with reports ranging from 3% to 20%. The present study systematically assesses 235 consecutively diagnosed African American cancer patients regarding recruitment onto cancer treatment clinical trials at Howard University Cancer Center between January 1, 2001, and December 31, 2002. Our intent is to determine the rate-limiting factors associated with enrolling African Americans onto clinical trials at a historically black medical institution.

Patients and Methods

Two hundred thirty-five consecutively diagnosed African American cancer patients were assessed for participation in clinical trials at Howard University Hospital and Cancer Center. The study population comprised 165 women and 70 men.

Results

The overall eligibility rate was 8.5% (20 of 235 patients); however, among those eligible, the enrollment rate (ie, enrollment among the eligible population) was 60.0% (12 of 20 patients). Comorbidities rendered 17.1% of the patient population ineligible for the trials. Advanced disease stage, associated with poor performance status, premature death, and short life expectancy, made an additional 10% of the patient population ineligible. Respiratory failure, HIV positivity, and anemia accounted for 37.8% of the comorbidities in this population. Cardiovascular diseases and renal insufficiency represented 16.2% of the comorbidities.

Conclusion

It was evident that study design exclusion and inclusion criteria rendered the majority of the study population ineligible. Among African Americans, comorbidity is a major issue that warrants considerable attention.

Hepatitis C virus in sickle cell disease

PURPOSE

To determine the prevalence of hepatitis C virus antibodies (anti-HCV) in patients with sickle cell disease.

PATIENTS AND METHODS

Between 1983 and 2001, 150 patients from the Howard University Hospital Center for Sickle Cell Disease were screened for HCV antibody (52% women, 48% men, mean age 34 years). Frozen serum samples from 56 adult sickle cell patients who had participated in previous surveys (1983-92) of HIV and HTLV-1 serology and who were tested in 1992 for anti-HCV antibody--when commercial ELISA test (Ortho) became available--were included in this paper. Of the 150 patients in the study, 132 had sickle cell anemia genotype (SS), 15 had sickle cell hemoglobin-C disease (SC) and three had sickle beta thalassemia. Clinical charts were reviewed for history of blood transfusion, IV drug abuse, homosexuality, tattooing, iron overload, and alcohol abuse.

RESULTS

Antibodies to HCV were detected in 53 patients (35.3%). Of the 55 patients who had frozen serum samples tested in 1992, 32 (58%) were reactive for anti-HCV, while only 21 of the 95 patients (22%) tested after 1992 were positive for HCV antibodies (P<0.001). Thirty-nine of 77 patients (51%) who received more than 10 units of packed red blood cells were positive for HCV antibody, and only 14 of 61 patients (23%) who received less than 10 units of packed red blood cells transfusion were positive for HCV antibodies (P<0.001). None of the 12 patients who never received transfusion were positive for HCV antibody. In the 53 anti-HCV positive patients, the mean alanine amino-transferase (ALT) value was 98- and 81 U/L, respectively, for males and females. These values were normal for the HCV-antibody negative patients. The aspartate amino-transferase (AST) and the total bilirubin were also higher in the anti-HCV positive patients compared to patients in the anti-HCV negative group. Forty-four patients (57.1%) who were transfused more than 10 units developed iron overload defined by a serum ferritin level higher than 1,000 ng/ml. A total of 20 of the patients with iron overload underwent liver biopsies. Seven of these 20 patients (35%) were HCV positive. These patients often had more severe liver disease and higher degree of iron deposition.

CONCLUSION

The prevalence of HCV antibody and iron overload is directly related to the number of blood transfusions in patients with sickle cell disease. The prevalence of HCV infection has decreased significantly, since blood donor screening for HCV became available. Chronic HCV infection and iron overload place sickle cell patients at risk for significant liver disease.

HCV in sickle cell disease

The sickle cell gene is common in the U.S. In fact 8% of African Americans are healthy carriers of the sickle cell trait (HbAS). People who are homozygous (HbSS) have severe disease. They have life-long anemia, chronic hemolysis, and also have at times hematological crises, which can worsen the anemia. Many patients require chronic transfusions and as a result, substantial proportions of sickle cell patients are at high risk for infection with blood-borne diseases-such as Hepatitis C Virus infection (HCV). The HCV antibody positivity is directly related to the number of transfusions given, and on average the prevalence rate in transfused patients is more than 10%. It is known that the combination of iron overload and HCV can lead to a more rapidly progressive liver disease. The treatment of HCV in sickle cell patients poses a challenge to clinicians. A novel approach described by some is the pre-treatment of these patients with hydroxyurea to increase the fetal hemoglobin, therefore decreasing the severity of Ribavirin-related hemolysis. Treatment with Peg-interferon alone has not been used to treat HCV in sickle cell patients, but in the setting of controlled clinical trials it would be feasible. This review explores the impact of HCV in sickle cell patients and the possible therapeutic options available to them.

Helicobacter pylori inhibits gastric cell cycle progression

Helicobacter pylori infection of the gastric mucosa is associated with changes in gastric epithelial cell proliferation. In vitro studies have shown that exposure to H. pylori inhibits proliferation of gastric cells. This study sought to investigate the cell cycle progression of gastric epithelial cell lines in the presence and absence of H. pylori. Unsynchronized and synchronized gastric epithelial cell lines AGS and KatoIII were exposed to H. pylori over a 24-h period. Cell cycle progression was determined by flow cytometry using propidium iodide (PI), and by analysis of cyclin E, p21, and p53 protein expression using Western blots. In the absence of H. pylori 40, 45, and 15% of unsynchronized AGS cells were in G(0)-G(1), S, and G(2)-M phases, respectively, by flow cytometry analysis. When AGS cells were cultured in the presence of H. pylori, the S phase decreased 10% and the G(0)-G(1) phase increased 17% after 24 h compared with the controls. KatoIII cells, which have a deleted p53 gene, showed little or no response to H. pylori. When G1/S synchronized AGS cells were incubated with media containing H. pylori, the G(1) phase increased significantly (25%, P < 0.05) compared with controls after 24 h. In contrast, the control cells were able to pass through S phase. The inhibitory effects of H. pylori on the cell cycle of AGS cells were associated with a significant increase in p53 and p21 expression after 24 h. The expression of cyclin E was downregulated in AGS cells following exposure of AGS cells to H. pylori for 24 h. This study shows that H. pylori-induced growth inhibition in vitro is predominantly at the G(0)-G(1) checkpoint. Our results suggest that p53 may be important in H. pylori-induced cell cycle arrest. These results support a role for cyclin-dependent kinase inhibitors in the G(1) cell cycle arrest exerted by H. pylori and its involvement in changing the regulatory proteins, p53, p21, and cyclin E in the cell cycle.

Natural killer cells induce activated murine B cells to secrete Ig

We previously demonstrated that dextran-conjugated anti-IgD antibodies (alpha delta-dex) induce proliferation of small, B cell-enriched murine spleen cells (Be cells), and in the presence of IL-2, stimulate Ig secretion in vitro. We have shown that alpha delta-dex-stimulated B cells provide an in vitro model for studying B cell activation by T cell-independent type 2 (TI-2) Ag, as exemplified by the bacterial polysaccharides. We now show that highly purified resting B cells, obtained by electronic cell sorting (Bsp cells), fail to secrete Ig in the presence of alpha delta-dex + IL-2. The alpha delta-dex + IL-2-induced Ig secretory response of Bsp cells is restored upon addition of splenic non-B, non-T cells or a pure population of in vitro-generated NK cells. Similarly, pretreatment of Be cells with anti-AsGm-1 plus complement inhibits Ig secretion in response to alpha delta-dex + IL-2. An IL-2-induced NK cell supernatant (NKSN) is equally potent at stimulating Ig secretion by alpha delta-dex-activated Bsp cells, indicating that cell contact between Bsp and activated NK cells is not required for this effect. IL-2 stimulates not only NK cells, but B cells as well, since addition of anti-IL-2 + anti-IL-2R antibodies to Bsp cell cultures, in the presence of alpha delta-dex + NKSN, inhibits Ig secretion. These data describe a novel animal model for NK cell-induced B cell maturation to Ig secretion and suggest a pathway for Ig production in response to T1-2 Ag.

Natural killer cells induce activated murine B cells to secrete Ig

We previously demonstrated that dextran-conjugated anti-IgD antibodies (alpha delta-dex) induce proliferation of small, B cell-enriched murine spleen cells (Be cells), and in the presence of IL-2, stimulate Ig secretion in vitro. We have shown that alpha delta-dex-stimulated B cells provide an in vitro model for studying B cell activation by T cell-independent type 2 (TI-2) Ag, as exemplified by the bacterial polysaccharides. We now show that highly purified resting B cells, obtained by electronic cell sorting (Bsp cells), fail to secrete Ig in the presence of alpha delta-dex + IL-2. The alpha delta-dex + IL-2-induced Ig secretory response of Bsp cells is restored upon addition of splenic non-B, non-T cells or a pure population of in vitro-generated NK cells. Similarly, pretreatment of Be cells with anti-AsGm-1 plus complement inhibits Ig secretion in response to alpha delta-dex + IL-2. An IL-2-induced NK cell supernatant (NKSN) is equally potent at stimulating Ig secretion by alpha delta-dex-activated Bsp cells, indicating that cell contact between Bsp and activated NK cells is not required for this effect. IL-2 stimulates not only NK cells, but B cells as well, since addition of anti-IL-2 + anti-IL-2R antibodies to Bsp cell cultures, in the presence of alpha delta-dex + NKSN, inhibits Ig secretion. These data describe a novel animal model for NK cell-induced B cell maturation to Ig secretion and suggest a pathway for Ig production in response to T1-2 Ag.

Comparative in vitro analysis of proliferation, Ig secretion, and Ig class switching by murine marginal zone and follicular B cells

We have previously demonstrated that activation of murine B cells by dextran-conjugated anti-IgD antibodies may serve as a polyclonal, in vitro model system for studying immune responses to T cell-independent type 2 (TI-2) Ag, as exemplified by the bacterial polysaccharides. Because in vivo Ig responses to TI-2 Ag are mediated primarily by B cells resident in the splenic marginal zone, we wished to determine whether this reflected an intrinsic difference in the responsiveness of marginal zone B cells (MZB) compared with follicular B cells (FB) to this class of Ag. In this report we demonstrate that highly purified MZB, isolated by electronic cell sorting, exhibit a lower proliferative response in vitro in response to unconjugated anti-Ig antibody as well as to dextran- or Sepharose-conjugated anti-IgM or anti-IgD antibodies, whereas they proliferate equal to or better than FB when stimulated by other B cell mitogens including LPS, Salmonella typhimurium mitogen, or anti-CD3-activated CD4+ Th2 cell clone. Despite the different proliferative responses of MZB and FB induced by anti-Ig, Ag receptor cross-linkage stimulates comparable increases in intracellular free calcium concentrations in both of these B cell populations. Furthermore, MZB secrete Ig and undergo Ig isotype switching to a comparable degree, relative to FB, in response to both T cell-dependent and T cell-independent stimuli. This suggests that the compartmentalization of TI-2 responses to the splenic marginal zone rather than the follicular zone reflects something other than the intrinsic responsiveness of the B cells from these two sites.

Comparative in vitro analysis of proliferation, Ig secretion, and Ig class switching by murine marginal zone and follicular B cells

We have previously demonstrated that activation of murine B cells by dextran-conjugated anti-IgD antibodies may serve as a polyclonal, in vitro model system for studying immune responses to T cell-independent type 2 (TI-2) Ag, as exemplified by the bacterial polysaccharides. Because in vivo Ig responses to TI-2 Ag are mediated primarily by B cells resident in the splenic marginal zone, we wished to determine whether this reflected an intrinsic difference in the responsiveness of marginal zone B cells (MZB) compared with follicular B cells (FB) to this class of Ag. In this report we demonstrate that highly purified MZB, isolated by electronic cell sorting, exhibit a lower proliferative response in vitro in response to unconjugated anti-Ig antibody as well as to dextran- or Sepharose-conjugated anti-IgM or anti-IgD antibodies, whereas they proliferate equal to or better than FB when stimulated by other B cell mitogens including LPS, Salmonella typhimurium mitogen, or anti-CD3-activated CD4+ Th2 cell clone. Despite the different proliferative responses of MZB and FB induced by anti-Ig, Ag receptor cross-linkage stimulates comparable increases in intracellular free calcium concentrations in both of these B cell populations. Furthermore, MZB secrete Ig and undergo Ig isotype switching to a comparable degree, relative to FB, in response to both T cell-dependent and T cell-independent stimuli. This suggests that the compartmentalization of TI-2 responses to the splenic marginal zone rather than the follicular zone reflects something other than the intrinsic responsiveness of the B cells from these two sites.

Long-term culture of human esophageal explants and cells

Human esophageal epithelium obtained from intermediate autopsies (less than 12 h) was maintained as cell and explant cultures. In order to develop a serum-free, defined media culture model, several medias and additives were evaluated. The viability and differentiation of the epithelial cells cultured with serum-free, Keratinocyte Growth Media (KGM, Clonetics Co., San Diego, CA) was improved over that of esophageal cells and explants cultured in either serum-supplemented CMRL 1066 (OCM), serum-free additive-supplemented CMRL 1066, or cimetidine-supplemented CMRL 1066. The KGM component EGF was determined to be trophic for esophagus cells on the basis of findings of increased 3H-TdR labelling in KGM cultures when compared to control cells grown in KGM without EGF (KBM). The morphologic pattern of the cytoskeletal proteins actin, keratin, and vimentin were characterized in isolated cell populations. The intermediate filaments, keratin, and vimentin were co-expressed in these epithelial cells. Esophageal explant viability, differentiation, and outgrowth from 15 cases were also evaluated in dishes coated with basement membrane associated proteins. Explants cultured in these dishes were equally well-preserved and differentiated. There were no significant differences in the explant histology when there was protein coating of the culture dishes, although one case showed improved outgrowth with laminin coating. A main advantage for using this culture system is that the same medium (KGM) can be used for both the culture of explants and isolated epithelial cells. Future applications of this model include determining: (1) the effect different concentrations of EGF and calcium in the media will have on esophageal proliferation and differentiation, and (2) the role of different basement membrane associated proteins on the plating efficiency of either isolated or outgrowth epithelial esophageal cells.