Search

Incidence and mortality rates for prostate cancer are higher in African-American (AA) men than in European-American (EA) men, but the biologic basis for this disparity is unclear. We carried out a detailed analysis of gene expression changes in prostate cancer compared with their matched benign tissues in a cohort of AA men and compared them with existing data from EA men. In this manner, we identified MNX1 as a novel oncogene upregulated to a relatively greater degree in prostate cancer from AA men. Androgen and AKT signaling play a central role in the pathogenesis of prostate cancer and we found that both of these signaling pathways increased MNX1 expression. MNX1 in turn upregulated lipid synthesis by stimulating expression of SREBP1 and fatty acid synthetase. Our results define MNX1 as a novel targetable oncogene increased in AA prostate cancer that is associated with aggressive disease. Cancer Res; 76(21); 6290–8. ©2016 AACR.

African American (AA) men have an approximately 60% higher incidence of prostate cancer (PCa) and have about two times greater risk of dying of the disease than their European American (EA) counterparts. Despite this staggeringly unequal burden of PCa incidence and outcome between AA and EA men, there is limited insight into the molecular mechanisms associated with this racial disparity. Using state-of-the-art mass spectrometry platform, we uncovered the very first metabolic and lipidomics landscape in PCa/benign adjacent tissue pairs and paired plasma and urine containing epidemiologic meta-data from ancestry-typed AA and EA men. A total of 190 polar and mid-polar metabolites and 495 lipids were measured in tissues and 183 metabolites and lipids were examined in the plasma and urine samples. AA PCa tissue and plasma signatures had unique alterations in metabolites and key enzymes associated with the methionine-homocysteine pathway, including adenosine and inosine levels, compared to corresponding tissues and plasma from EA case controls and EA PCa tissues. Intriguingly, methionine levels in AA PCa were also portrayed by distinct dietary practices in these patients. In addition, AA PCa tissues demonstrated unique patterns of bioenergetic metabolites and accumulated lipids reflecting impaired mitochondrial activity and TCA cycle. Further characterization of these first-in-the-field findings demonstrating reprogrammed metabolism in AA PCa relative to EA tumors could reveal insights into the biologic basis of PCa disparities and novel areas for therapeutic intervention. Citation Format: Stacy M. Lloyd*, Jie H. Gohlke*, Sumanta Basu*, Vasanta Putluri,Shaiju K Vareed, Rebeca San Martin, Thekkelnaycke Rajendiran, Tiffany A. Dorsey, Bandana Prasad, Rajni Sonavane, Uttam Rasaily, James Henderson, Balasubramanyam Karanam, Harene Venghatakrishnan, Salil Bhowmik, Alexander Zaslavsky,Nilanjan Guha, Rick Kittles, Stefan Ambs, Michael Ittmann,David Rowley, Ganesh Palapattu, Nagireddy Putluri,George Michailidis, Arun Sreekumar. Metabolomic landscape of African American prostate cancer: Insights into the biologic basis of the racial disparity [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr B92.

Retinoblastoma is a pediatric eye cancer affecting children usually less than five years of age. Inactivation of both the copies of the RB1 gene in a child's retina initiates cancer formation. Whil...

Metabolic dysfunction or reprogramming is the underlying cause of many diseases including cancer. In this study, we looked into the transcriptomic and metabolomic profile of retinoblastoma (Rb), a pediatric eye cancer, from tumor and normal tissue, aqueous humor, vitreous humor and tear. The samples were collected from enucleated eyes of 9 subjects and 2 deceased controls, whose cause of death is not due to any eye related disease. The study was corroborated with cell line models of retinoblastoma, used for metabolic phenotyping. Combined pathway analysis of transcriptomics data from subject tissue samples and retinoblastoma cell line WERI-Rb-1 revealed a significant overlap in the differentially regulated genes belonging to both glycolysis and OXPHOS pathways. The results were correlated with Rb1 overexpressed and its respective control also. To better understand the implications of these two major pathways in the progression of retinoblastoma, metabolic study using Seahorse analyzer enables measurement of extracellular flux (oxygen consumption rate and extracellular acidification rate) to provide insight into mitochondrial function and glycolytic activity. Using a pharmacological approach, the contribution of glucose, glutamine and fatty acid oxidation pathways can be assessed. Overall the study demonstrates the value of using a multi-omics approach with functional metabolic profiling to understand the extent of metabolic dysfunction in retinoblastoma and also to identify implications of various biological pathways in Rb. Citation Format: Nilanjan Guha, Carolina Livi, Vishnu Suresh Babu, Lisa Winer, Deepak SA, Syed Lateef, Seetaraman Gundimeda, Arunkumar Padmanabhan, Brian Dranka, Arkasubhra Ghosh. Understanding metabolic dysfunction in retinoblastoma development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2515. doi:10.1158/1538-7445.AM2017-2515

Background: AA men with PCa will die at a rate nearly 2.5 times higher than their EA counterparts. Presently, no mechanism has been described to explain the differences observed between AA and EA men with PCa; yet, many have interrogated the role of social and anthropometric data on PCa outcomes within these populations. Therefore, to obtain better insights into the molecular aspects of PCa disparities, we examined metabolomic and gene expression profiles of PCa and matched adjacent benign tissue from AA and EA men. Metabolomics is defined as the study of all the small molecule metabolites produced by cellular processes in the body. We hypothesize that racially distinct metabolic pathways may contribute to PCa health disparities and also delineate mechanistic biological pathways. Methodology: A total of 190 polar and mid-polar metabolites were measured using mass spectrometry across 50 and 28 PCa/benign tissue pairs from AA and EA men, respectively. Likewise, gene expression microarray analysis was performed on 48 and 21 PCa/benign tissue pairs from AA and EA men, and gene set enrichment (GSEA) analysis was performed. Ancestry informative markers were genotyped and ancestry estimates were determined. Metabolic profiles of AA and EA PCa and benign adjacent pairs were compared using paired t-tests. FDR corrected p-values were used to detect differential metabolites and genes. Biological validation was performed using tissue microarrays, qPCR, and western blots. Results: Unique biochemical alterations associated with AA tumors were identified. Relative to EA tumors, AA tumors had significant alterations in the cysteine/methionine pathway; specifically accumulations of adenosine were most prominent in AA PCa, as well as urine. Protein and transcript levels of Adenosine Deaminase (ADA), an enzyme that converts SAM-derived adenosine to inosine was significantly down regulated in AA PCa, a finding validated in both tissue and cell lines. GSEA analysis revealed that genes involved in the immune system were prominent among AA PCa compared to EA PCa. To this end, significant inverse correlations between ADA and CD4+, CD8+, and CD68+ levels were also identified. Conclusions: Taken together, this integromics approach generated data that alludes to the existence of an efficient immune escape mechanism in AA PCa, which may explain the disparity facing AA men with PCa. Citation Format: Stacy M. Lloyd, Jie Gohlke, Sumanta Basu, Salil Bhowmik, Vasanta Putluri, Kimal Rajapakshe, Cristian Coarfa, Michael Ittmann, Ganesh Palapattu, Nagireddy Putluri, George Michailidis, Arun Sreekumar. An Integromics Approach Identifies Immune Escape as a Potential Mechanism for Prostate Cancer Disparities. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr PR10.

Background: AA men with PCa will die at a rate nearly 2.5 times higher than their EA counterparts. Presently, no mechanism has been described to explain the differences observed between AA and EA men with PCa; yet, many have interrogated the role of social and anthropometric data on PCa outcomes within these populations. However, when these factors are statistically controlled, the differences in incidence, morbidity, and mortality between AA and EA PCa persist. These findings support the notion that biological factors are one of the major driving forces of PCa disparities. Therefore, to obtain better insights into the molecular aspects of PCa disparities, we examined metabolomic and gene expression profiles of PCa and matched adjacent benign tissue from AA and EA men. Metabolomics is defined as the study of all the small molecule metabolites produced by cellular processes in the body. We hypothesize that racially distinct metabolic pathways and the associated bioprocesses, may contribute to PCa health disparities Methodology: A total of 190 polar and mid-polar metabolites were measured using mass spectrometry across 50 and 28 PCa/benign tissue pairs from AA and EA men, respectively. Likewise, gene expression microarray analysis was performed on 48 and 21 PCa/benign tissue pairs from AA and EA men. Ancestry informative markers were genotyped and ancestry estimates were determined. Metabolic profiles of AA and EA PCa and benign adjacent pairs were compared using paired t-tests. FDR corrected p-values were used to detect differential metabolites and genes. Results: Unique biochemical alterations associated with AA tumors were identified. Pathways such as cysteine/methionine, arginine/proline and de novo purine biosynthesis were enhanced in AA PCa. Metabolites such as cystathione, cysteine, and S-Adenosylhomocysteine (SAH), are elevated in AA PCa compared to matched adjacent benign. Consistent with this, transcript and protein levels of DNA Methyl Transferase 1 (DNMT1) and Cystathione Beta Synthase (CBS) were elevated in AA PCa tissues and cell lines. Interestingly, protein and transcript levels of Adenosine Deaminase, an enzyme that converts SAM-derived adenosine to inosine was significantly down regulated in AA PCa, both in tissues and cell lines. Consistent with this, accumulated levels of adenosine were found in AA PCa. Conclusions: Taken together, the metabolomics data alludes to the existence of an efficient immune escape mechanism in AA PCa. Corroborating this, analysis of gene expression data from AA men with PCa also reveals enriched immune escape pathways. Citation Format: Stacy M. Lloyd, Jie Gohlke, Sumanta Basu, Salil Bhowmik, Vasanta Putluri, Rashmi Krishnapurnam, Kimal Rajapakshe, Cristian Coarfa, Nilanjan Guha, SA Deepak, Arunkumar Padmanabhan, Mohammed Sayeeduddin, Patricia Castro, Michael Ittmann, Ganesh Palapattu, Nagireddy Putluri, George Michailidis, Arun Sreekumar. An integromics approach identifies immune escape as a potential mechanism for prostate cancer disparities. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr A65.

This study illustrates a multi-omics approach combining transcriptomics and metabolomics datasets to study molecular events leading to progression of retinoblastoma. Retinoblastoma is a pediatric ocular cancer affecting children usually less than five years of age. It is a complex disease predisposed primarily by biallelic inactivating mutations in the RB1 gene. This gene has essential roles in cell cycle, differentiation, chromosome stability and is implicated in other functions. From a cohort of 9 patients undergoing enucleation of the affected eyes, we obtained tumor, aqueous humor, vitreous humor and tear samples. We obtained retina, aqueous humor and vitreous humor from enucleated eyes of 2 deceased pediatric controls, whose cause of death is not due to any eye related disease. The patients comprise of both high and low clinical and pathological risks. In the first stage of the study, we performed mRNA and miRNA gene expression using microarrays followed by pathway analysis to identify gene enrichment that would enable functional characterization of tumors. Differential expression analysis was carried out using moderated t-test with Benjamini Hochberg multiple testing correction. 108 (p≤0.05, fold change≥10) genes were found to be unique to patients possessing high risk of metastasis. Pathway analysis revealed key pathways that are known to be involved in the progression of retinoblastoma including cell cycle and Rap1 signaling pathway. Many of these responders were verified by RT-PCR and corroborated by immuno histochemistry studies. The study also revealed 18 novel miRNAs which had not been previously implicated in the disease, with a significant overlap of the miRNA target list with our mRNA expression data set. Metabolomics studies were performed using monophasic solvent extraction of aqueous, vitreous and tear samples. The extracted metabolites were analyzed on Accurate Mass QTOF mass spectrometer in positive and negative mode on a reverse phase C18 and HILIC columns. Data dependent MS/MS analysis was performed to confirm the compounds. Pathway analysis of the differentially expressed metabolites revealed enrichment of several pathways, including nucleotide metabolism and amino acids among others. Combined pathway analysis of metabolomics and transcriptomics data was performed in order to gain an understanding of the interrelationship between changes in gene expression and metabolomic profile. The results show overlap of key cellular pathways which can be mechanistically linked to disease progression. The study provide new biological insights that are made accessible by combining data from different biological and biochemical domains with a comprehensive integrated method. The information is useful not only to correlate expression markers with disease mechanism but also to better predict appropriate chemotherapy regimens and identify new mechanisms to treat even advanced stages of retinoblastoma. Citation Format: Nilanjan Guha, Deepak SA, Syed Lateef, Seetaraman Gundimeda, Arunkumar Padmanabhan, Carolina B Livi, Nigel Skinner, Arkasubhra Ghosh, Ashwin Mallipatna, Vishnu Suresh Babu, Arun Sreekumar. An integrated approach to identify functional signaling modules in retinoblastoma cancer progression. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3753. doi:10.1158/1538-7445.AM2015-3753