Characterizing commonalities and differences between the breast and prostate cancer metabotypes in African-American cohorts (part I)
ABSTRACT: Thus, we aimed to 1) understand mechanisms related to the onset and progression of BCa, 2) identify precursors and targets for prevention and therapy for each stage, grade and subtype which may contribute to the disparate impact of BCa in African American women, and 3) Identify common and different BCa metabolite markers versus PCa markers.
Project description:Thus, we aimed to 1) understand mechanisms related to the onset and progression of BCa, 2) identify precursors and targets for prevention and therapy for each stage, grade and subtype which may contribute to the disparate impact of BCa in African American women, and 3) Identify common and different BCa metabolite markers versus PCa markers.
Project description:Prostate cancer (PCa) tends to be more aggressive and lethal in African Americans (AA) compared to European Americans (EA). To further understand the thebiological risk factors associated with PCa disparities observed in AA and EA patients, we performed microRNA profiling using Agilent Human miRNA arrays to identify the differentially expressed microRNAs beween: 1) AA and EA PCa patients; 2) AA PCa vs. AA normal; and 3) EA PCa vs. EA normal. 54 prostate biopsy specimens (tumor and adjacent normal tissues) were collected from 14 African American and 13 European American prostate cancer patients. 54 RNA samples, purified from the collected biopy specimens using Qiagen miRNeasy kit, were process and applied to Agilent human miRNA arrays. Array data was normalized and analyzed using Agilent GeneSpring program.
Project description:African-American (AA) men have both a higher incidence and significantly higher mortality rates from prostate cancer (PCa) than European American (EA) men. In this study we have carried out a detailed analysis of both CNAs and gene expression changes in PCas from AA men compared to their matched benign tissues. We have identified MNX1 as a novel androgen regulated oncogene that is upregulated to a greater degree in AA PCa compared to EA PCa. Furthermore, RGS12 is a novel tumor suppressor on 4p16.3 that is preferentially deleted in AA PCa which negatively regulates MNX1 expression. Overall design: In this study we have carried out a detailed analysis of gene expression changes in PCas from AA men compared to their matched benign tissues. two-group comparison
Project description:Prostate cancer (PCa) tends to be more aggressive and lethal in African Americans (AA) compared to European Americans (EA). To further understand the biological factors accounting for the PCa disparities observed in AA and EA patients, we performed gene profiling analysis using Affymetrix human exon 1.0 ST arrays to identify the differentially expressed genes in AA and EA patients. 35 prostate biopsy specimens (tumor and adjacent normal tissues) were collected from 20 African American and 15 European American prostate cancer patients. RNA samples, purified from the collected biopy specimens, were process and applied to Affymetrix human exon ST 1.0 arrays. Array data was normalized, batch corrected and analyzed (1-way ANOVA) using Partek Genomics Suite program.
Project description:African American (AA) men have a 60% higher incidence and two times greater risk of dying of prostate cancer (PCa) than European American men, yet there is limited insight into the molecular mechanisms driving this difference. To our knowledge, metabolic alterations, a cancer-associated hallmark, have not been reported in AA PCa, despite their importance in tumor biology. Therefore, we measured 190 metabolites across ancestry-verified AA PCa/benign adjacent tissue pairs (n?=?33 each) and identified alterations in the methionine-homocysteine pathway utilizing two-sided statistical tests for all comparisons. Consistent with this finding, methionine and homocysteine were elevated in plasma from AA PCa patients using case-control (AA PCa vs AA control, methionine: <i>P</i>?=?.0007 and homocysteine: <i>P</i>?<?.0001), biopsy cohorts (AA biopsy positive vs AA biopsy negative, methionine: <i>P</i>?=?.0002 and homocysteine: <i>P</i>?<?.0001), and race assignments based on either self-report (AA PCa vs European American PCa, methionine: <i>P</i>?=?.001, homocysteine: <i>P</i>?<?.0001) or West African ancestry (upper tertile vs middle tertile, homocysteine: <i>P</i>?<?.0001; upper tertile vs low tertile, homocysteine: <i>P</i>?=?.002). These findings demonstrate reprogrammed metabolism in AA PCa patients and provide a potential biological basis for PCa disparities.
Project description:Molecular mechanisms underlying the health disparity of prostate cancer (PCa) have not been fully determined. In this study, we applied bioinformatic approach to identify and validate dysregulated genes associated with tumor aggressiveness in African American (AA) compared to Caucasian American (CA) men with PCa. We retrieved and analyzed microarray data from 619 PCa patients, 412 AA and 207 CA, and we validated these genes in tumor tissues and cell lines by Real-Time PCR, Western blot, immunocytochemistry (ICC) and immunohistochemistry (IHC) analyses. We identified 362 differentially expressed genes in AA men and involved in regulating signaling pathways associated with tumor aggressiveness. In PCa tissues and cells, NKX3.1, APPL2, TPD52, LTC4S, ALDH1A3 and AMD1 transcripts were significantly upregulated (p?<?0.05) compared to normal cells. IHC confirmed the overexpression of TPD52 (p?=?0.0098) and LTC4S (p?<?0.0005) in AA compared to CA men. ICC and Western blot analyses additionally corroborated this observation in PCa cells. These findings suggest that dysregulation of transcripts in PCa may drive the disparity of PCa outcomes and provide new insights into development of new therapeutic agents against aggressive tumors. More studies are warranted to investigate the clinical significance of these dysregulated genes in promoting the oncogenic pathways in AA men.
Project description:BACKGROUND:Expression of p16 is increased in a number of malignancies, including prostate cancer (PCa). Recent studies in a European cohort showed that expression of p16 is correlated with expression of the TMPRSS2/ERG (T/E) fusion protein. The T/E fusion is significantly less common in PCas in African American (AA) men. Thus, it would be predicted that p16 expression should be less common in PCas in AA men. We, therefore, sought to compare the expression of p16 in benign prostate and PCas from AA and European American (EA) men. METHODS:Immunohistochemistry for p16 and ERG was performed on tissue microarrays constructed from radical prostatectomies performed on AA and EA veterans. Staining was scored and the scores compared with demographic, clinical and pathological parameters. Percent of West African ancestry in the AA cohort was assessed using ancestry informative markers. RESULTS:Contrary to our predictions, p16 expression was similar in the cancers in the AA and EA cohorts. Consistent with prior reports, expression of p16 was quite low in benign prostate tissues from EA patients but surprisingly was significantly higher in benign tissues from AA patients. Expression of p16 was significantly associated with a family history of PCa in AA men. In addition, p16 was associated with ERG expression in AA PCa. CONCLUSIONS:While overall expression of p16 is similar in PCas from the two racial groups, the expression of p16 in benign tissues from a subset of AA men and the stronger correlation with ERG expression implies that there are different mechanisms for p16 overexpression in PCas from the two racial groups.
Project description:Clinical challenges exist in reducing prostate cancer (PCa) disparities. The RNA splicing landscape of PCa across racial populations has not been fully explored as a potential molecular mechanism contributing to race-related tumour aggressiveness. Here, we identify novel genome-wide, race-specific RNA splicing events as critical drivers of PCa aggressiveness and therapeutic resistance in African American (AA) men. AA-enriched splice variants of PIK3CD, FGFR3, TSC2 and RASGRP2 contribute to greater oncogenic potential compared with corresponding European American (EA)-expressing variants. Ectopic overexpression of the newly cloned AA-enriched variant, PIK3CD-S, in EA PCa cell lines enhances AKT/mTOR signalling and increases proliferative and invasive capacity in vitro and confers resistance to selective PI3K? inhibitor, CAL-101 (idelalisib), in mouse xenograft models. High PIK3CD-S expression in PCa specimens associates with poor survival. These results highlight the potential of RNA splice variants to serve as novel biomarkers and molecular targets for developmental therapeutics in aggressive PCa.
Project description:African American (AA) men have a significantly higher mortality rate from prostate cancer (PCa) compared to European American (EA) men. AA men are twice as likely to die from PCa compared to EA men and 8 times as likely as Asian American men to die from PCa. The biological basis for these differences in PCa mortality are unclear. We carried out Copy Number Alteration (CNA) studies on a new set of 40 highly tumor-enriched primary PCas and matched benign prostate tissues from AA men using high resolution Affymetrix 6.0 SNP arrays and expression array analysis using RNAs (GSE71016) from the same tissues using high purity tumors from AA men and matched benign tissue. We have confirmed the specific loss of 4p16.3 described previously and identified a novel tumor suppressor gene, RGS12 at this locus that shows significantly decreased expression in AA PCa but not EA EA PCa. Overall design: Profiles were generated on Affymetrix SNP 6.0 chips. In all, 40 tumors and 40 paired normal samples were profiled, 40 profiles in all. Each tumor was centered on its corresponding normal pair to define copy number alterations (CNA) in that tumor.
Project description:BACKGROUND:Breast cancer subtype can be classified using standard clinical markers (estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2)), supplemented with additional markers. However, automated biomarker scoring and classification schemes have not been standardized. The aim of this study was to optimize tumor classification using automated methods in order to describe subtype frequency in the African American Breast Cancer Epidemiology and Risk (AMBER) consortium. METHODS:Using immunohistochemistry (IHC), we quantified the expression of ER, PR, HER2, the proliferation marker Ki67, and two basal-like biomarkers, epidermal growth factor receptor (EGFR) and cytokeratin (CK)5/6, in 1381 invasive breast tumors from African American women. RNA-based (prediction analysis of microarray 50 (PAM50)) subtype, available for 574 (42%) cases, was used to optimize classification. Subtype frequency was calculated, and associations between subtype and tumor characteristics were estimated using logistic regression. RESULTS:Relative to ER, PR and HER2 from medical records, central IHC staining and the addition of Ki67 or combined tumor grade improved accuracy for classifying PAM50-based luminal subtypes. Few triple negative cases (<?2%) lacked EGFR and CK5/6 expression, thereby providing little improvement in accuracy for identifying basal-like tumors. Relative to luminal A subtype, all other subtypes had higher combined grade and were larger, and ER-/HER2+ tumors were more often lymph node positive and late stage tumors. The frequency of basal-like tumors was 31%, exceeded only slightly by luminal A tumors (37%). CONCLUSIONS:Our findings indicate that automated IHC-based classification produces tumor subtype frequencies approximating those from PAM50-based classification and highlight high frequency of basal-like and low frequency of luminal A breast cancer in a large study of African American women.