1,25-Dihydroxyvitamin D3 Suppresses Prognostic Survival Biomarkers Associated with Cell Cycle and Actin Organization in a Non-Malignant African American Prostate Cell Line

Vitamin D3 is a steroid hormone that confers anti-tumorigenic properties in prostate cells. Serum vitamin D3 deficiency has been associated with advanced prostate cancer (PCa), particularly affecting African American (AA) men. Therefore, elucidating the pleiotropic effects of vitamin D on signaling pathways, essential to maintaining non-malignancy, may provide additional drug targets to mitigate disparate outcomes for men with PCa, especially AA men. We conducted RNA sequencing on an AA non-malignant prostate cell line, RC-77N/E, comparing untreated cells to those treated with 10 nM of vitamin D3 metabolite, 1α,25(OH)2D3, at 24 h. Differential gene expression analysis revealed 1601 significant genes affected by 1α,25(OH)2D3 treatment. Pathway enrichment analysis predicted 1α,25(OH)2D3- mediated repression of prostate cancer, cell proliferation, actin cytoskeletal, and actin-related signaling pathways (p < 0.05). Prioritizing genes with vitamin D response elements and associating expression levels with overall survival (OS) in The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA PRAD) cohort, we identified ANLN (Anillin) and ECT2 (Epithelial Cell Transforming 2) as potential prognostic PCa biomarkers. Both genes were strongly correlated and significantly downregulated by 1α,25(OH)2D3 treatment, where low expression was statistically associated with better overall survival outcomes in the TCGA PRAD public cohort. Increased ANLN and ECT2 mRNA gene expression was significantly associated with PCa, and Gleason scores using both the TCGA cohort (p < 0.05) and an AA non-malignant/tumor-matched cohort. Our findings suggest 1α,25(OH)2D3 regulation of these biomarkers may be significant for PCa prevention. In addition, 1α,25(OH)2D3 could be used as an adjuvant treatment targeting actin cytoskeleton signaling and actin cytoskeleton-related signaling pathways, particularly among AA men.

Population-enriched innate immune variants may identify candidate gene targets at the intersection of cancer and cardio-metabolic disease

Both cancer and cardio-metabolic disease disparities exist among specific populations in the US. For example, African Americans experience the highest rates of breast and prostate cancer mortality and the highest incidence of obesity. Native and Hispanic Americans experience the highest rates of liver cancer mortality. At the same time, Pacific Islanders have the highest death rate attributed to type 2 diabetes (T2D), and Asian Americans experience the highest incidence of non-alcoholic fatty liver disease (NAFLD) and cancers induced by infectious agents. Notably, the pathologic progression of both cancer and cardio-metabolic diseases involves innate immunity and mechanisms of inflammation. Innate immunity in individuals is established through genetic inheritance and external stimuli to respond to environmental threats and stresses such as pathogen exposure. Further, individual genomes contain characteristic genetic markers associated with one or more geographic ancestries (ethnic groups), including protective innate immune genetic programming optimized for survival in their corresponding ancestral environment(s). This perspective explores evidence related to our working hypothesis that genetic variations in innate immune genes, particularly those that are commonly found but unevenly distributed between populations, are associated with disparities between populations in both cancer and cardio-metabolic diseases. Identifying conventional and unconventional innate immune genes that fit this profile may provide critical insights into the underlying mechanisms that connect these two families of complex diseases and offer novel targets for precision-based treatment of cancer and/or cardio-metabolic disease.

Sex differences in IL-3, IL-4, and IL-7 correlation with cholesterol and triglyceride levels in African Americans with high HbA1c

Background

Nearly 30 million Americans have diabetes; majority are diagnosed with type 2 diabetes (T2D). Low grade inflammation is associated with T2D which influences a network of serum cytokines. IL-3, IL-4, and IL-7 play coordinated pathogenic roles in many inflammatory diseases including T2D and non-fatty liver disease. It has been previously reported high circulating glucose influences serum cytokine levels and cholesterol metabolism. However, further studies are needed to delineate the relationship between cytokine serum levels, cholesterol, and triglycerides metabolism.

Methods

A total of 232 serum samples were collected from African Americans: 161 women and 71 men. This group consists of 95 normal HbA1c and 106 high HbA1c participants. Most participants had a BMI &gt; 30 (n=171). Cytokines were measured using multiplexing assays from Luminex X-MAP® technology.

Results

In the presence of high HbA1c, there is a trend increase in serum levels of IL-4 in both men and women. In women participants, IL-3 (R=−0.41, P=0.02) is inversely correlated to BMI, but not in men. IL-3 is positively correlated to VLDL cholesterol in women with normal HbA1c. HDL is positively correlated with IL-3 (R=0.20, P=0.04). VLDL is positively correlated with IL-4 (R=0.79, P=0.007), in men with normal HbA1c. Triglycerides were positively correlated to IL-4 (R=0.80, P=0.006) and IL-3 (R=0.56, P=0.05) in men with normal HbA1c.

Conclusion

The involvement of IL-3, IL-4, IL-7 are linked to cholesterol metabolism but are possibly regulated differently between sexes. The evidence of these correlations provides a basis of understanding that could be utilized to provide intervention to reduce the complications of T2D.

Supported by NIH NIMHD U54MD012392

COVID-19 vaccine hesitancy in underserved communities of North Carolina

BACKGROUND

In the United States, underserved communities including Blacks and Latinx are disproportionately affected by COVID-19. This study sought to estimate the prevalence of COVID-19 vaccine hesitancy, describe attitudes related to vaccination, and identify correlates among historically marginalized populations across 9 counties in North Carolina.

METHODS

We conducted a cross-sectional survey distributed at free COVID-19 testing events in underserved rural and urban communities from August 27 -December 15, 2020. Vaccine hesitancy was defined as the response of "no" or "don't know/not sure" to whether the participant would get the COVID-19 vaccine as soon as it became available.

RESULTS

The sample comprised 948 participants including 27.7% Whites, 59.6% Blacks, 12.7% Latinx, and 63% female. 32% earned <$20K annually, 60% owned a computer and ~80% had internet access at home. The prevalence of vaccine hesitancy was 68.9% including 62.7%, 74%, and 59.5% among Whites, Blacks, and Latinx, respectively. Between September and December, the largest decline in vaccine hesitancy occurred among Whites (27.5 percentage points), followed by Latinx (17.6) and only 12.0 points among Blacks. 51.2% of respondents reported vaccine safety concerns, 23.7% wanted others to get vaccinated first, and 63.1% would trust health care providers about the COVID-19 vaccine. Factors associated with hesitancy in multivariable logistic regression included being female (OR = 1.90 95%CI [1.36, 2.64]), being Black (OR = 1.68 1.16, 2.45]), calendar month (OR = 0.76 [0.63, 0.92]), safety concerns (OR = 4.28 [3.06, 5.97]), and government distrust (OR = 3.57 [2.26, 5.63]).

CONCLUSIONS

This study engaged the community to directly reach underserved minority populations at highest risk of COVID-19 that permitted assessment of vaccine hesitancy (which was much higher than national estimates), driven in part by distrust, and safety concerns.

Community Engagement Practices at Research Centers in U.S. Minority Institutions: Priority Populations and Innovative Approaches to Advancing Health Disparities Research

This paper details U.S. Research Centers in Minority Institutions (RCMI) Community Engagement Cores (CECs): (1) unique and cross-cutting components, focus areas, specific aims, and target populations; and (2) approaches utilized to build or sustain trust towards community participation in research. A mixed-method data collection approach was employed for this cross-sectional study of current or previously funded RCMIs. A total of 18 of the 25 institutions spanning 13 U.S. states and territories participated. CEC specific aims were to support community engaged research (94%); to translate and disseminate research findings (88%); to develop partnerships (82%); and to build capacity around community research (71%). Four open-ended questions, qualitative analysis, and comparison of the categories led to the emergence of two supporting themes: (1) establishing trust between the community-academic collaborators and within the community and (2) building collaborative relationships. An overarching theme, building community together through trust and meaningful collaborations, emerged from the supporting themes and subthemes. The RCMI institutions and their CECs serve as models to circumvent the historical and current challenges to research in communities disproportionately affected by health disparities. Lessons learned from these cores may help other institutions who want to build community trust in and capacities for research that addresses community-related health concerns.

COVID-19 Vaccine Hesitancy in Underserved Communities of North Carolina

Background

In the United States, underserved communities including Blacks and Latinx are disproportionately affected by COVID-19, and widespread vaccination is critical for curbing this pandemic. This study sought to estimate the prevalence of COVID-19 vaccine hesitancy, describe attitudes related to vaccination, and identify correlates among racial minority and marginalized populations across 9 counties in North Carolina.

Methods

We conducted a cross-sectional survey with a self-administered questionnaire distributed at free COVID-19 testing events in underserved rural and urban communities from August 27 - December 15, 2020. Vaccine hesitancy was defined as the response of "no" or "don't know/not sure" to whether the participant would get the COVID-19 vaccine as soon as it became available.

Results

The sample comprised 948 participants including 27.7% Whites, 59.6% Blacks, 12.7% Latinx, and 63% female. Thirty-two percent earned <$20K annually, 60% owned a computer and ∼80% had internet access at home. The prevalence of vaccine hesitancy was 68.9% including 62.7%, 74%, and 59.5% among Whites, Blacks, and Latinx, respectively. Between September and December, the largest decline in vaccine hesitancy occurred among Whites (27.5 percentage points), followed by Latinx (17.6) and the smallest decline was among Black respondents (12.0). 51.2% of the respondents reported vaccine safety concerns, 23.7% wanted others to get of the respondents reported they would trust health care providers with information about the COVID-19 vaccine. Factors associated with hesitancy in multivariable logistic regression included being female (OR=1.90 95%CI[1.36, 2.64]), being Black (OR=1.68 [1.106 2.45]), calendar month (OR=0.76 [0.63, 0.92]), safety concerns (OR=4.28 [3.06, 5.97]), and government distrust (OR=3.57 [2.26, 5.63]).

Conclusions

This study reached underserved minority populations in a number of different locations to investigate COVID-19 vaccine hesitancy. We built on existing relationships and further engaged the community, stake holders and health department to provide free COVID-19 testing. This direct approach permitted assessment of vaccine hesitancy (which was much higher than national estimates), distrust, and safety concerns.

Highlights

This study surveyed 948 adults at COVID-19 testing sites in 9 counties of North Carolina between August 27 and December 15, 2020 where vaccine hesitancy was widespread including 74% in Blacks, 62.7% in Whites and 59.5% in Latinx.Vaccine hesitancy declined over time but remained high for Blacks.On-site surveys conducted in underserved areas that were paper-based and self-administered permitted reaching adults with no internet (17%), no cell phone (20%), no computer (40%) and yearly incomes less than 20K (31%).Widespread vaccine hesitancy in predominately minority communities of NC must be addressed to successfully implement mass COVID-19 vaccination programs.

Rural Community Engagement for Health Disparities Research: The Unique Role of Historically Black Colleges and Universities (HBCUs)

Reducing health disparities in rural communities of color remains a national concern. Efforts to reduce health disparities often center on community engagement, which is historically the strategy used to provide rural minority populations with support to access and utilize health information and services. Historically Black Colleges and Universities (HBCUs), with their origins derived from social injustices and discrimination, are uniquely positioned to conduct this type of engagement. We present the "Research with Care" project, a long-standing positive working relationship between North Carolina Central University (NCCU) and rural Halifax County, North Carolina, demonstrating an effective campus-community partnership. The importance of readiness to implement Community-based Participatory Research (CBPR) principles is underscored. As demonstrated by the NCCU-Halifax partnership, we recommend leveraging the positive associations of the HBCU brand identity as a method of building and sustaining meaningful relationships with rural Black communities. This underscores the role and value of HBCUs in the health disparities research arena and should be communicated and embraced.

Protective Innate Immune Variants in Racial/Ethnic Disparities of Breast and Prostate Cancer

Individuals of African descent are disproportionately affected by specific complex diseases, such as breast and prostate cancer, which are driven by both biological and nonbiological factors. In the case of breast cancer, there is clear evidence that psychosocial factors (environment, socioeconomic status, health behaviors, etc.) have a strong influence on racial disparities. However, even after controlling for these factors, overall phenotypic differences in breast cancer pathology remain among groups of individuals who vary by geographic ancestry. There is a growing appreciation that chronic/reoccurring inflammation, primarily driven by mechanisms of innate immunity, contributes to core functions associated with cancer progression. Germline mutations in innate immune genes that have been retained in the human genome offer enhanced protection against environmental pathogens, and protective innate immune variants against specific pathogens are enriched among populations whose ancestors were heavily exposed to those pathogens. Consequently, it is predicted that racial/ethnic differences in innate immune programs will translate into ethnic differences in both pro- and antitumor immunity, tumor progression, and prognosis, leading to the current phenomenon of racial/ethnic disparities in cancer. This review explores examples of protective innate immune genetic variants that are (i) distributed disproportionately among racial populations and (ii) associated with racial/ethnic disparities of breast and prostate cancer.

Abstract D114: VIitamin D signaling of immune-related genes in diverse prostate cancer cancer cell lines

BACKGROUND: African American (AA) men are disproportionately affected by both prostate cancer (PCa) and vitamin D deficiency compared with European American (EA) men. Vitamin D deficiency is linked to increased PCa aggressiveness and mortality. Inflammation also plays an important role in PCa pathogenesis and progression, and expression of immune-related in genes in PCa tissues differs significantly between AAs and EAs. While evidence linking vitamin D and immune response to PCa remains scarce, previous studies demonstrated that vitamin D has anti-inflammatory effects in prostate tissue and mediates immune-related gene expression. Therefore, we hypothesize that vitamin D deficiency in AA men may alter the expression of immune-related genes associated with prostatic inflammation and PCa progression. METHODS: This study examined the effects of vitamin Don the expression of vitamin D- and immune-related genes. Weexposed a racially diverse panel of PCa cell lines—MDA-PCa-2b (AA), RC77T/E (AA), PC3 (EA), 22Rv1 (EA), and DU145 (EA)—to various concentrations (2.5 nM, 10 nM, 50 nM) of 25-hydroxyvitamin D (25(OH)D) and 1,25 dihydroxyvitamin D (1,25(OH)2D) for 24 hours, and quantified transcript levels and protein expression of VDR, RXRa, RXRb, LRP2, CYP27B1, GDF15, GFRAL, TNFa, IL6, IL8, and IGFBP3 with qPCR and immunoblotting. RESULTS:All cell lines expressed basal levels of VDR, RXRa, and RXRbconfirming the function of vitamin D signaling within PCa cells. Of the downstream immune-related genes tested, we observed a trend demonstrating that vitamin D treatment induced the greatest upregulation in either transcript and/or protein levels among the AA PCa cell lines RC77T/E and/or MDA-PCa-2b. In particular, LRP2, GDF15, TNFa, IL6, IL8, and IGFBP3 significantly increased in AA PCa cell lines exposed to either 25(OH)D or 1,25(OH)2D. CONCLUSIONS: These findings provide insight into a potential differential regulation of immune-related pathways by vitamin D in AA men compared to EA men with PCa. Further studies are warranted to better define the immune profile in prostatic tissue in response to vitamin D deficiency in AA men, and the downstream inflammatory effects on the microenvironment and tumor aggressiveness.

Citation Format: Madhavi Bathina, Leanne Woods-Burnham, Mya S Walker, K Sean Kimbro, Rick A Kittles. VIitamin D signaling of immune-related genes in diverse prostate cancer cancer cell lines [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D114.

Serum Cytokines are regulated in African Americans with High HbA1c

Background

Low grade inflammation is associated with T2D resulting from a cadre of serum cytokines. IL3, IL4, IL7, IL-17A, GM-CSF, and GM-CSF play a coordinated pathogenic role in many inflammatory diseases. It has been previously reported high circulating HbA1c influences serum cytokine levels and cholesterol metabolism.

Methods

A total of 120 serum samples were collected from African Americans: 68 women and 52 men. This group consists of 45 normal HbA1c and 71 high HbA1c participants. Clinical metabolic parameters were measured. Cytokines were measured using Luminex X-MAP® technology. A series of unpaired t-test were computed to determine if there were significant differences between participants with and without elevated HbA1c. Pairwise Pearson Correlation (r) test was computed for each variable.

Results

In women, IL-3 expression was upregulated 1.7-fold in the presence of high circulating glucose. In men, IL-3 expression was downregulated 1.5-fold. Individuals with high HbA1c exhibit a negative correlation between IL-3 and BMI in men and women. Male serum IL-7 levels decrease in presence of circulating high glucose while female serum IL-7 levels increase. Normal HbA1c men have a 2.7-fold higher serum IL-7 level than women with normal HbA1c. Women participants have a positive correlation with serum IL-7 and HbA1c, as well as BMI. These correlations are lost in men. In the presence of high HbA1c, there is an increase in serum levels of IL-17A, G-CSF, and GM-CSF in women with high HbA1c.

Conclusion

An increase in HbA1c increases the expression of inflammatory cytokines and the risk of metabolic disease. Our data suggests that, in a sex specific manner, several cytokines may regulate cholesterol and lipid management in T2D.

Genetic Ancestry Analysis Reveals Misclassification of Commonly Used Cancer Cell Lines

BACKGROUND

Given the scarcity of cell lines from underrepresented populations, it is imperative that genetic ancestry for these cell lines is characterized. Consequences of cell line mischaracterization include squandered resources and publication retractions.

METHODS

We calculated genetic ancestry proportions for 15 cell lines to assess the accuracy of previous race/ethnicity classification and determine previously unknown estimates. DNA was extracted from cell lines and genotyped for ancestry informative markers representing West African (WA), Native American (NA), and European (EUR) ancestry.

RESULTS

Of the cell lines tested, all previously classified as White/Caucasian were accurately described with mean EUR ancestry proportions of 97%. Cell lines previously classified as Black/African American were not always accurately described. For instance, the 22Rv1 prostate cancer cell line was recently found to carry mixed genetic ancestry using a much smaller panel of markers. However, our more comprehensive analysis determined the 22Rv1 cell line carries 99% EUR ancestry. Most notably, the E006AA-hT prostate cancer cell line, classified as African American, was found to carry 92% EUR ancestry. We also determined the MDA-MB-468 breast cancer cell line carries 23% NA ancestry, suggesting possible Afro-Hispanic/Latina ancestry.

CONCLUSIONS

Our results suggest predominantly EUR ancestry for the White/Caucasian-designated cell lines, yet high variance in ancestry for the Black/African American-designated cell lines. In addition, we revealed an extreme misclassification of the E006AA-hT cell line.

IMPACT

Genetic ancestry estimates offer more sophisticated characterization leading to better contextualization of findings. Ancestry estimates should be provided for all cell lines to avoid erroneous conclusions in disparities literature.

Abstract 4983: IRAK4 and breast cancer cell migration in culture and zebrafish xenografts

Growing evidence indicates that incongruities in the inflammatory and immune response pathways contribute to tumorigenesis. We seek to explore the underlying biological mechanisms that both promote and inhibit breast cancer (BrCa) tumorigenesis via innate immune pathways involving the Toll-like receptors (TLRs) and their associated agonists. Women of African descent (AA) are an understudied group at high risk for developing aggressive BrCa. Therefore, we previously examined the occurrence of single nucleotide polymorphisms (SNPs) in selected genes along TLR pathways among a small cohort of AA women with breast cancer and identified a SNP in the central regulatory kinase IRAK4 that was associated with increased breast cancer risk. In silico predictions suggest that the IRAK4 minor variant rs4251545 codes for an Ala428Thr missense mutation that introduces a potential phosphorylation site in the extreme carboxy terminus (XCT) of the IRAK-4 kinase domain. The current study tests the hypothesis that functional IRAK4 promotes BrCa cell growth and migration using in vitro (cultured human BrCa cell) and in vivo (zebrafish BrCa xenograft) models.

Materials and methods: ER-positive MCF7 and triple-negative MDA-MB-231 (wild-type IRAK4) and MDA-MB-468 (IRAK4 w/rs4251545) human BrCa cell lines were compared. Cultured cells were treated for 24 hours with or without IRAK1/4 inhibitor. Cell migration and cell growth among BrCa lines were compared using wound healing and crystal violet assays, respectively. BrCa cell xenografts of zebrafish (ZF) embryos were examined for metastatic potential and the physiologic effects of morpholino inhibition of ZF IRAK4 among embryos with and without BrCa xenograft burdens were compared. In addition, zebrafish/tumor xenograft model was used to address the in vivo metastatic property of BrCa cells and the effect of targeting zebrafish irak4 using morpholino (MO) knockdown approach in the tumor-host environment on the metastatic behavior of MDA-MB-468 cells.

Results: Treatment with IRAK1/4 inhibitor delayed BrCa migration and growth in all BrCa cells lines. Relative in vivo migration rates/ (or metastatic property) of MDA-MB-231 and MDA-MB-468 BrCa xenografts in ZF resemble in vitro rates, in which MDA-MB-231s migrate metastasized more rapidly/ (or aggressively). MO inhibition of ZF zebrafish IRAK4 irak4 gene expression in the host environment MDA-MB-468 xenografted fish inhibits MDA-MB-468 metastasis in the zebrafish/tumor xenograft.

Conclusion: Inhibition of IRAK4 reduces BrCa growth and migration in vitro and in vivo in zebrafish. The development of drugs that target IRAK4 and other regulators of the innate immune pathway may help modulate BrCa tumor progression.

Citation Format: K. Sean Kimbro, Karine Ferri-Lagneau, Jamil Haider, Susan Yeyeodu, Xiaohe Yang, TinChung Leung. IRAK4 and breast cancer cell migration in culture and zebrafish xenografts. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4983. doi:10.1158/1538-7445.AM2014-4983

IRAK4 and TLR3 Sequence Variants may Alter Breast Cancer Risk among African-American Women

Mounting evidence suggests that imbalances in immune regulation contribute to cell transformation. Women of African descent are an understudied group at high risk for developing aggressive breast cancer (BrCa). Therefore, we examined the role of 16 innate immune single nucleotide polymorphisms (SNPs) in relation to BrCa susceptibility among 174 African-American women in Atlanta, GA, USA. SNPs were examined in germ-line DNA collected from 102 BrCa patients and 72 women with benign nodules using SNPstream methodology. Inheritance of the TLR3 rs10025405 GG genotype was associated with an 82% decrease in BrCa risk. In contrast, individuals who possessed at least one IRAK4 rs4251545 T allele had a 1.68- to 4.99-fold increase in the risk of developing BrCa relative to those with the referent genotype (OR = 4.99; 95% CI = 1.00, 25.00; p = 0.0605). However, the IRAK4 rs4251545 locus was only significant under the additive genetic model (p trend = 0.0406). In silico predictions suggest IRAK4 rs4251545 SNP falls within a transcription enhancer/silencer region of the gene and codes for an Ala428Thr amino acid change. This missense mutation introduces a potential phosphorylation site in the extreme carboxy terminus (XCT) of the IRAK4 kinase domain. Preliminary molecular modeling predicts that this SNP stabilizes two alpha helices within the XCT on the surface of the IRAK4 kinase domain and increases the size of the groove between them. Our in silico results, combined with previous reports noting the presence of IRAK4 and XCT fragments in mouse and human serum, suggest the possibility that the XCT subdomain of IRAK4 possesses biological function. These findings require further evaluation and validation in larger populations, additional molecular modeling as well as functional studies to explore the role of IRAK4 and its XCT in cell transformation and innate immunity.

Contribution of toll-like receptor signaling pathways to breast tumorigenesis and treatment

Mounting evidence indicates that anomalies in the inflammatory and immune response pathways are essential to tumorigenesis. However, tumor-based innate immunity initiated by transformed breast epithelia tissues has received much less attention. This review summarizes published reports on the role of the toll-like receptor signaling pathway on breast cancer risk, disease progression, survival, and disease recurrence. Specifically, we discuss the underlying biological mechanisms that contribute to the tumorigenic and/or anti-tumorigenic properties of toll-like receptors and their associated agonists in relation to breast tumorigenesis and cancer treatment. Further, we use results from preclinical, clinical, and population-based studies as prompts for the exploration of new and more effective breast cancer therapies. As the knowledge base of innate immunity's involvement in breast cancer progression increases, current and new immune-modifying strategies will be refined to effectively treat breast cancer.

Abstract 931: Innate immunity-related sequence variants (TOLLIP, TLR2) as predictors of prostate cancer risk among men of African descent

Emerging genome-wide association studies suggest genome variation plays a rather important, yet largely uncharacterized, role in dissecting the genetic underpinnings of prostate cancer (PCa) health disparities. Moreover, recent advances in molecular and genetic studies demonstrate a relationship between chronic/recurrent inflammation and complex diseases. In terms of prostate cancer, it is speculated that chronic or recurrent inflammation, attributed to persistent exposure to pathogens may alter the tissue microenvironment that favors tumor growth. Despite the fact that men of African descent suffer disproportionately from PCa and may have a natural selection advantage toward inheriting innate immunity signaling loci linked with pro-inflammatory response, it remains to be determined whether variant innate immunity-related alleles will explain the higher PCa risk and disease severity in this sub-group. With the ultimate goal of understanding the genetic underpinnings of PCa health disparities, we set out to systematically evaluate the impact of innate immunity-related single nucleotide polymorphisms (SNPs) in relation to PCA risk among 3,200 men of African and European descent. We hypothesized that individuals inheriting high-risk innate immunity loci (linked with elevated pro-inflammatory response) will have an increased risk of developing PCa relative to those with the referent genotypes. In order to evaluate the effects of innate immunity sequence variants on PCa we used SNP profile data collected from 2277 European participants of the Cancer Genetic Markers of Susceptibility (CGEMS) project (1176 cases, 1101 controls) and 923 men of African descent (224 cases, 699 controls). Using a case-control study design, we evaluated the independent effects of 19 variant innate immunity genes (e.g., TLR 1-4, CD14, IRAK2, IRF3, TOLLIP) in relation to PCa risk using logistic regression and multi-factor dimensionality reduction (MDR) modeling. Inheritance of at least one minor TOLLIP rs5743899G (p = 0.002) and the TLR-2 rs4696480A allele (linked with enhanced cytokine production) was significantly associated with a 2.1-4.5 fold increase prostate cancer susceptibility among men of African descent. Notably, the TOLLIP marker remained significant even after adjusting for multiple comparisons following MDR with permutation testing (p = 0.01). These markers were not associated with PCa among European participants. In summary, variations in genes involved in the innate immunity signaling may play a role in PCa risk among men of African Descent in the current study. However, these findings require validation in larger and ethnically diverse sub-populations. Such efforts will help to identify and validate new genetic fingerprints with the capacity to unravel the genetic contributions of prostate cancer incidence and mortality disparities among high-risk subgroups.

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 931.

Aberrant STYK1 expression in ovarian cancer tissues and cell lines

Background

Overexpression of STYK1, a putative serine/threonine and tyrosine receptor protein kinase has been shown to confer tumorigenicity and metastatic potential to normal cells injected into nude mice. Mutation of a tyrosine residue in the catalytic STYK1 domain attenuates the tumorigenic potential of tumor cells in vivo, collectively, suggesting an oncogenic role for STYK1.

Methods

To investigate the role of STYK1 expression in ovarian cancer, a panel of normal, benign, and ovarian cancer tissues was evaluated for STYK1 immunoreactivity using STYK1 antibodies. In addition, mRNA levels were measured by reverse transcription PCR and real-time PCR of estrogen receptors, GPR30 and STYK1 following treatment of ovarian cell lines with estrogen or G1, a GPR30 agonist, as well as western analysis.

Results

Our data showed higher expression of STYK1 in cancer tissues versus normal or benign. Only normal or benign, and one cancer tissue were STYK1-negative. Moreover, benign and ovarian cancer cell lines expressed STYK1 as determined by RT-PCR. Estradiol treatment of these cells resulted in up- and down-regulation of STYK1 despite estrogen receptor status; whereas G-1, a GPR30-specific agonist, increased STYK1 mRNA levels higher than that of estradiol.

Conclusion

We conclude that STYK1 is expressed in ovarian cancer and is regulated by estrogen through a GPR30 hormone-signaling pathway, to the exclusion of estrogen receptor-alpha.

Impact on bone of an estrogen receptor-alpha gene loss of function mutation

CONTEXT

The kindred described is the only known instance of a germ line loss of function mutation of estrogen receptor (ER)-alpha.

OBJECTIVE

Our objective was to assess the impact of a loss of function mutation in the ER-alpha gene on histomorphometry, bone volumetric density, bone geometry and skeletal growth, and ER-alpha heterozygosity on spine density and adult height in an extended pedigree.

DESIGN AND PARTICIPANTS

A longitudinal follow-up of the propositus with homozygous loss of function mutation of ER-alpha and single contact evaluation of the kindred were performed.

MAIN OUTCOME MEASURES

Iliac crest bone biopsy and peripheral quantitative computed tomography of propositus with serial measures of areal spine bone mineral density (aBMD) by dual-energy x-ray absorptiometry and bone age were performed. Members of pedigree were evaluated for ER-alpha mutation carrier status and spine aBMD.

RESULTS

Bone biopsy revealed marked osteopenia (cortex: 641 microm), low trabecular volume (10.6%), decreased thickness (76.2 microm), normal trabecular number, and low activation frequency (0.099/yr). Radial periosteal circumference was similar, endosteal circumference larger, and trabecular and cortical volumetric bone mineral density markedly lower (158 and 1092 mg/cm(3), respectively) than controls. Spine aBMD at age 28.5 yr (0.745 g/cm(2)) decreased to 0.684 g/cm(2) (Z score -3.85) in 3.5 yr. Bone age advanced from 15-17.5 yr. Kindred analysis revealed that gene carriers had spine aBMD Z scores less than zero (P = 0.003), but carriers and nonmutant members were similar (-0.84 +/- 0.26 vs. -0.64 +/- 0.16).

CONCLUSION

Homozygous ER-alpha disruption markedly affects bone growth, mineral content, and structure but not periosteal circumference. ER-alpha heterozygosity appears to not impair spine aBMD.

Insulin-like growth factor-I-dependent up-regulation of ZEB1 drives epithelial-to-mesenchymal transition in human prostate cancer cells

The epithelial-to-mesenchymal transition (EMT) is crucial for the migration and invasion of many epithelial tumors, including prostate cancer. Although it is known that ZEB1 overexpression promotes EMT primarily through down-regulation of E-cadherin in a variety of cancers, the soluble ligands responsible for the activation of ZEB1 have yet to be identified. In the present study, we investigated the role of insulin-like growth factor-I (IGF-I) in the regulation of ZEB1 during EMT associated with prostate tumor cell migration. We found that ZEB1 is expressed in highly aggressive prostate cancer cells and that its expression correlates directly with Gleason grade in human prostate tumors (P < 0.001). IGF-I up-regulates ZEB1 expression in prostate cancer cells exhibiting an epithelial phenotype. In prostate cancer cells displaying a mesenchymal phenotype, ZEB1 inhibition reverses the suppression of E-cadherin protein and down-regulates the expression of the mesenchymal markers N-cadherin and fibronectin. Furthermore, ZEB1 blockade decreases migratory and invasive potential in ARCaP(M) compared with the control. These results identify ZEB1 as a key transcriptional regulator of EMT in prostate cancer and suggest that the aberrant expression of ZEB1 in prostate cancer cells occurs in part in response to IGF-I stimulation.

A novel gene STYK1/NOK is upregulated in estrogen receptor-alpha negative estrogen receptor-beta positive breast cancer cells following estrogen treatment

The human STYK1/NOK protein is approximately 30-35% similar to mouse fibroblast growth factor receptor 3 and a kinase homologue in D. melanogaster in the tyrosine protein kinase region. STYK1/NOK was identified as being up regulated in MDA-MB-231, an estrogen receptor-alpha negative breast cancer cell line, following 12 h of estrogen treatment at 1x10(-9) M. On further investigation of STYK1/NOK in estrogen treated cell line MDA-MB-231, STYK1/NOK was up regulated at 6 h post treatment when compared to untreated cells. We also investigated the expression levels of STYK1/NOK in other breast cancer cell lines MCF-7, MDA-MB-231, BT-549, and MDA-MB-435S using QRT-PCR. In addition, the analysis of message accumulation was increased with other synthetic estrogen response modifiers. We propose that the regulation of STYK1/NOK is achieved independent of ERalpha and suggests further investigation to the relevance of this kinase in breast cancer progression.

Hypoxia-inducible factor-1 in human breast and prostate cancer

The tumor microenvironment is best characterized as a fluctuation of hypoxia and nutrient deprivation, which leads to epigenetic and genetic adaptation of clones and increased invasiveness and metastasis. In turn, these hypoxic adaptations make the tumors more difficult to treat and confer increased resistance to current therapies. Part of this adaptation is the regulation of gene products in response to hypoxia. Many of these hypoxia-regulated genes are mediated by the hypoxia-inducible factor 1 (HIF-1) complex, which is composed of a heterodimer pair of HIF-1alpha and HIF-1beta. This heterodimer binds to the promoter of hypoxia-responsive genes, while interacting with other transcription factors, such as p300, signal and transducer of transcription 3, and Redox effector factor 1/apurinic/apyrimidinic endonuclease. HIF-1alpha levels itself can be regulated by hypoxia transcriptionally and post-translationally through ubiquitination; but the magnitude of the response is modulated by several other pathways, including free radicals that affect crosstalk with HIF-1alpha/HIF-1beta transcriptional activities. HIF-1alpha has emerged as an important transcription factor in breast cancer and prostate cancer biology, and is expressed in the early stages of mammary and prostate carcinogenesis. Its expression is correlated with diagnostic and prognostic indicators for early relapse and metastatic disease, thus making HIF-1alpha a potential prognostic biomarker in proteomic assessments of breast and prostate cancers. The importance of HIF-1alpha in tumor progression makes it a logical target for chemoprevention strategies in patients at higher genetic risk of breast and prostate cancer with Cox 2 inhibitors or 2-methoxyestradiol, as well as a target for new approaches to inhibiting angiogenesis. The crosstalk between estrogen signaling pathways and HIF-1alpha is still not fully defined in breast cancer, but downstream estrogen receptor signaling may be a candidate for estrogen modulation of HIF-1alpha levels. In prostate cancer, androgens upregulate HIF-1alpha through androgen-regulated autocrine receptor tyrosine kinase receptor signaling. This review will put into perspective the role of HIF-1alpha in endocrine oncology and present new data on HIF-1alpha signaling and the potential for targeted therapies, including combinatory hormonal therapies.

Incorporating a new bioinformatics component into genetics at a historically black college: outcomes and lessons

Many students at minority-serving institutions are underexposed to Internet resources such as the human genome project, PubMed, NCBI databases, and other Web-based technologies because of a lack of financial resources. To change this, we designed and implemented a new bioinformatics component to supplement the undergraduate Genetics course at Clark Atlanta University. The outcomes of the Bioinformatics course were assessed. During the first week of the semester, students were assigned the Felder-Soloman's Index of Learning Styles Inventory. The overwhelming majority of students were visual (82.1%) and sequential (75.0%) learners. Furthermore, pre- and postcourse surveys were administered during the first and the last week of the course to assess learning, confidence level, and mental activity. These indicated students increased the number of hours spent using computers and doing homework. Students reported confidence in using computers to study genetics increased, enabling them to better visualize and understand genetics. Furthermore, students were more mentally engaged in a more social learning environment. Although the students appreciated the value of the bioinformatics component, they reported the additional work load was substantial enough to receive additional course credit.

Identification and characterization of Rhodopseudomonas spp., a purple, non-sulfur bacterium from microbial mats

A species of facultative photo-organotrophic, purple, non-sulfur bacterium was isolated from mixed-species microbial mats, characterized and examined for metal tolerance and bioremediation potential. Contributing mats were natural consortia of microbes, dominated by cyanobacteria and containing several species of bacteria arranged in a laminar structure, stabilized within a gel matrix. Constructed microbial mats were used for bioremediation of heavy metals and organic chemical pollutants. Purple, non-sulfur bacteria are characteristically found in lower strata of intact mats, but their contributing function in mats survival and function by mediating the chemical environment has not been explored. The gram-negative rod-shaped bacterium, reported here, produced a dark red culture under phototrophic conditions, reproduced by budding and formed a lamellar intracytoplasmic membrane (ICM) system parallel to cytoplasmic membrane, which contained bacteriochlorophyll a and carotenoids. This strain was found to have multiple metal resistances and to be effective in the reductive removal of Cr(VI) and the degradation of 2,4,6-trichlorophenol. Based on the results obtained from morphology, nutrient requirements, major bacteriochlorophyll content, GC content, random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) profile and 16S-rDNA phylogenetic analysis, this member of the microbial mats may be identified as a new strain of the genus Rhodopseudomonas.

Two proteins bind to a novel motif in the promoter of the myelin basic protein gene from mouse

The box 1 and 2 motif of the myelin basic protein (MBP) promoter is a potential regulatory sequence of the MBP transcription unit. A DNA fragment that contained the sequence of the box 1 and 2 motif from mouse was synthesized, and its protein binding properties were examined by gel-shift assays. The box 1 and 2 probe and nuclear extracts from mouse brain generated a pattern of six major DNA-protein complexes (a, b, c, d, e, and f). The box 1 and 2 probe and nuclear extracts from oligodendrocyte-like glioma cells 1C10 generated a pattern of DNA-protein complexes that exhibited only complexes a, b, e, and f. Complex b generated by extracts from 1C10 cells, however, was very intense compared to any of the other complexes. It was determined that dephosphorylation of the proteins in nuclear extracts from 1C10 cells with acid phosphatase significantly altered their DNA binding properties. Two proteins of minimum M, approximately 32 and approximately 38 kDa (MBP32 and MBP38) that bind to the box 1 and 2 motif were identified in these nuclear extracts by using a UV crosslinking method. MBP32 and MBP38 are found in cell types and tissues known to express the golli transcription unit of the golli-MBP gene complex and may be involved in the modulation of the MBP unit in those cells.

Box I and II motif from myelin basic protein gene promoter binds to nuclear proteins from rodent brain

The box I and II motif located within the promoter of the myelin basic protein gene contains a simian virus 40 T-antigen-binding site, a MyoD/E2a-binding site, and a glucocorticoid receptor-binding site. We have found proteins within nuclear extracts from adult mouse brain, rat embryonic cerebral cortex in culture, and a mouse oligodendrocyte-like cell line that bind to a 32P-labeled synthetic DNA fragment containing the sequences of the box I and II motif. Three major complexes (A, B, and C) were seen in gel-shift assays. Only complexes A and B were competed out by the unlabeled box I and II fragment or by another synthetic DNA fragment that also contains sequences similar to a glucocorticoid receptor-binding site. Therefore, complexes A and B were thought to be specific. The expression pattern of the proteins responsible for the formation of these complexes was also assessed during development in mouse brain.

The structural complexities of the myelin basic protein gene from mouse are also present in shark

The Golli-mbp gene complex contains two overlapping transcription units with two distinct promoters, of which the downstream (myelin basic protein [mbp]) promoter is more frequently used. A previous comparison of the downstream promoter sequences from shark and mouse allowed the identification of two DNA sequences called the boxes I and II and the wobble zone. The boxes I and II sequence is a composite cis-acting motif that is thought to be involved in the regulation of the downstream promoter. It contains sequences similar to T-antigen, MyoD/E2A, and glucocorticoid receptor-binding sites. The wobble zone codes for an exon (5a in the nomenclature of Campagnoni et al., 1993) that is included in messenger RNAs transcribed from the upstream promoter. The polypeptides encoded by this exon from shark and mouse are 86 and 84 amino acids long, respectively. These polypeptides are overall 59% identical and include a region (residues 41-75 in shark and 39-73 in mouse) that is 89% identical between the two species. A primary sequence analysis showed that each of these polypeptides contains an N-glycosylation site, phosphorylation sites for Ca2+/calmodulin-dependent protein kinase, protein kinase C and casein kinase II, and partial ATP- and GTP-binding sites. The shark polypeptide also contains a phosphorylation site for proline-directed protein kinase. These observations are consistent with the notion that the intricate structure and regulation of the Golli-mbp gene complex arose during vertebrate evolution within a common ancestor to sharks and mammals.

2',3'-Dideoxythymidine 5'-triphosphate inhibition of DNA replication and ultraviolet-induced DNA repair synthesis in human cells: evidence for involvement of DNA polymerase delta

It is well established that DNA replication and ultraviolet-induced DNA repair synthesis in mammalian cells are aphidicolin-sensitive and thus are mediated by one or both of the aphidicolin-sensitive DNA polymerases, alpha and/or delta. Recently, it has been shown that DNA polymerase delta is much more sensitive to inhibition by the nucleotide analogue 2',3'-dideoxythymidine 5'-triphosphate (ddTTP) than DNA polymerase alpha but is less sensitive than DNA polymerase beta [Wahl, A. F., Crute, J. J., Sabatino, R. D., Bodner, J. B., Marraccino, R. L., Harwell, L. W., Lord, E. M., & Bambara, R. A. (1986) Biochemistry 25, 7821-7827]. We find that DNA replication and ultraviolet-induced DNA repair synthesis in permeable human fibroblasts are also more sensitive to inhibition by ddTTP than polymerase alpha and less sensitive than polymerase beta. The Ki for ddTTP of replication is about 40 microM and that of repair synthesis is about 25 microM. These are both much less than the Ki of polymerase alpha (which is greater than 200 microM) but greater than the Ki of polymerase beta (which is less than 2 microM). These data suggest that DNA polymerase delta participates in DNA replication and ultraviolet-induced DNA repair synthesis in human cells.