The microbiome of cervical cancer: exploring the link between bacteria and tumor
Khiem Lam BioResource Research Oregon State University, Corvallis, OR
Andrey Morgun, MD, PhD College of Pharmacy Oregon State University, Corvallis, OR What is cervical cancer?
• A malignant tumor of the cervix • Fourth common cancer in Cervical Cancer women worldwide • Caused by human papillomavirus (HPV)
http://www.cdc.gov/cancer/hpv/statistics/cases.htm Most HPV infections do not lead to cervical cancer
HPV infection is necessary but not sufficient in causing cervical cancer.
Shulzhenko, et al., 2014 Role of bacteria in driving human cancer
http://www.pyroenergen.com/articles13/images/gastric-ulcer-pylori.jpg Previous models of cervical cancer show specific host gene expression patterns and role of HPV, but has not explored role of other microbes (bacteria)
What is the role of microbiota in cervical cancer?
Host Genes Microbiota ? Cell Cycle Antiviral Response
Epithelial Differentiation
Mine, K., et al. Nature Comm. 2013.
HPV The use of network analysis to analyze host- microbe interactions
Data
In vitro/vivo Network Experiment Reconstruction Cervical Cancer Microbiome
Network Interrogation Methodology
Cervical Cancer DNA Bacterial DNA Tumor Samples Extraction Detection using qPCR
16s rRNA Sequencing & QIIME Analysis
Relative Abundance Gene Expression Data of Microbes
Analysis of Microbes and In vitro Experiments Host Gene Expression The use of network analysis to analyze host- microbe interactions
Data
In vitro/vivo Network Experiment Reconstruction Cervical Cancer Microbiome
Network Interrogation Why sequencing?
Only small proportion of microbiota can be cultivated High-throughput, cheaper, less labor intensive, single sample analysis Three main sequencing methods
Shotgun Sequencing 16S rRNA gene RNA-Seq of DNA sequencing
Schluenzen F, Tocilj, et al. 2000 Cell. http://rnaseq.uoregon.edu/ http://www.discoveryandinnovation.com/BIOL202/notes/lecture24.html 16S rRNA Sequencing
• Most common bacterial sequencing • Uses MiSeq sequencing platform • Well-described 16S rRNA gene
Sample 1 Sample 2 Sample 3 16S 16S adapter adapter primer primer ….. barcodes ……….….n
http://www.alimetrics.net/en/index.php/dna-sequence-analysis Caporaso et al., 2012 ISME J Low bacterial DNA content in tissue samples
• Bacterial DNA amounts checked using qPCR
Soil
Intestine Stool Lung Tumor Kidney
High Low Bacterial DNA Bacterial DNA Increased bacteria content with cancer FIGO stage progession
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ANOVA P = 0.0119 Cochran-Armitage test for trend: Tukey IV-I (0.020) IV-II (0.011) IV-III (p=0.012) P = 0.0309 Data Processing (QIIME)
OTU1 OTU2 OTU3
OTU OTU Abundance Bin Similar Sequences Sample into Operational Identify OTU in Sample and Sequencing Data Taxonomic Units (OTUs) Relative Frequencies
Compare OTUs Remove Primers to Databases and Quality Filter Bacterial abundance compared to healthy body sites
100% other 90% g__ (o_Bacteroidales) 80% g__Campylobacter g__Faecalibacterium 70% g__Corynebacterium 60% g__Peptoniphilus g__Porphyromonas 50% g__Staphylococcus 40% g__Anaerococcus
Relative Abundance Relative g__Alistipes 30% g__Fusobacterium 20% g__Propionibacterium g__Bacteroides 10% g__Lactobacillus 0% g__Prevotella cervical cancer vagina stool skin Differentially expressed genes of cervical cancer
Host Genes
Cell Cycle
Antiviral Response Epithelial Differentiation Gene expression and microbiome data in cervical cancer patients
Cervical Cancer Tumors
cDNA Microarray 16S rRNA Sequencing
Host Genes Microbiota Cell Cycle ? 14.9% Prevotella Antiviral Response 9.6% Fusobacterium
Epithelial Differentiation 7.3% Porphyromonas
Mine, K., et al. Nature Comm. 2013. The use of network analysis to analyze host- microbe interactions
Data
In vitro/vivo Network Experiment Reconstruction Cervical Cancer Microbiome
Network Interrogation Correlation analysis to infer causal relationships
https://utw10426.utweb.utexas.edu/Topics/Correlation/Text_files/image002.jpg Differentially expressed genes of cervical cancer
Host Genes
Cell Cycle
Antiviral Response Epithelial Differentiation Network reconstruction of bacterial groups reveal a model of interactions
Relative Family Assignment Abundance (%, mean) Planococcaceae 6.71 Halomonadaceae 3.34 Bacillaceae 1.87 Halobacteriaceae 1.11 Moraxellaceae 0.95 Pseudomonadaceae 0.90 Corynebacteriaceae 0.68 Prevotellaceae 0.41 Node: Operational Taxonomic Unit (OTU) Blue edge: positive correlation Red edge: negative correlation Transkingdom network shows relationship between regulatory cancer genes and abundant bacteria
Differentially Expressed Cancer Gene Network
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Transkingdom Network Microbial Network Transkingdom network shows relationship between regulatory cancer genes and abundant bacteria The use of network analysis to analyze host- microbe interactions
Data
In vitro/vivo Network Experiment Reconstruction Cervical Cancer Microbiome
Network Interrogation Bipartite Betweenness Centrality reveals top bacterial candidate in cervical cancer
Bipartite Betweenness Centrality number of shortest paths from all orange nodes to all blue that pass through that node
Low BC High BC
Microbes Genes
Dong, X., et al. Bioinformatics and Biology Insights. 2015. Selection of Bacterial Candidates Selection of Bacterial Candidates
Transkingdom Network Bacterial Candidates
Prevotella bivia Prevotella buccalis Prevotella disiens Prevotella oris Bi-Partite Betweenness Centrality Alignment to SILVA (16S) Literature Search Lactobacillus crispatus Availability (control)
Prevotella spp. are listed as anaerobic Lactobacillus crispatus is listed as facultative anaerobe The use of network analysis to analyze host- microbe interactions
Data
In vitro/vivo Network Experiment Reconstruction Cervical Cancer Microbiome
Network Interrogation Co-Culture Experiments
-24 0 6/24 Hour
HeLa
RNeasy qScript Kit Mini Kit
5% CO2 Anaerobic
Bacterial RNA Extraction Cells plated at Reverse qPCR treatment On-Column 75,000 cells/well Transcription (10 ng/well cDNA) MOI 1/10 DNase Treatment Gene targets for RT-qPCR
Bi-partite betweenness centrality results between DEGs and microbes
epithelial cell Node name subnet all degs antiviral cell cycle differentiation regulation IFI44L antiviral 358 38 380 188 UP LAMP3 antiviral 69 10 67 95 UP CEP70 cell cycle 13 108 15 189 UP S100PBP cell cycle 18 88 22 94 UP TPX2 cell cycle 72 169 41 270 UP NEK2 cell cycle 237 280 189 325 UP RFC4 cell cycle 277 378 196 254 UP
Listed rank out of 738 genes in network
Rank less than 50 highlighted Initial gene expression results Selection of Bacterial Candidates
Transkingdom Network Bacterial Candidates
Prevotella bivia Prevotella buccalis Prevotella disiens Prevotella oris Bi-Partite Betweenness Centrality Alignment to SILVA (16S) Literature Search Lactobacillus crispatus Availability (control)
Prevotella spp. are listed as anaerobic Lactobacillus crispatus is listed as facultative anaerobe Selection of Bacterial Candidates
Transkingdom Network Bacterial Candidates
Prevotella bivia Prevotella disiens
Bi-Partite Betweenness Centrality Alignment to SILVA (16S) Lactobacillus crispatus Literature Search (control) Availability
Prevotella spp. are listed as anaerobic Lactobacillus crispatus is listed as facultative anaerobe Co-Culture Experiments
-24 0 24 Hour
HeLa
RNeasy qScript Kit Mini Kit
5% CO2 Anaerobic
Bacterial RNA Extraction Cells plated at Reverse qPCR treatment On-Column 75,000 cells/well Transcription (10 ng/well cDNA) MOI 10 DNase Treatment The use of network analysis to analyze host- microbe interactions
Data
In vitro/vivo Network Experiment Reconstruction Cervical Cancer Microbiome
Network Interrogation LAMP3 shows up-regulation in Prevotella bivia treatment
*p-value < 0.05, one-sided paired t-test 2^-dCT between treatment and no bacteria control CEP70 and S100PBP shows up-regulation in Prevotella disiens treatment
*p-value < 0.05, one-sided paired t-test 2^-dCT between treatment and no bacteria control Summary
Transkingdom Network Selection of Bacterial Candidates
Prevotella bivia Prevotella disiens L. crispatus (control)
In vitro Bacterial Co-Culture Bi-Partite Betweenness Centrality
Prevotella sp.
Betweenness Centrality Betweenness Bacterial Groups What’s next?
Data
In vitro/vivo Network Experiment Reconstruction
Network Interrogation • RNA sequencing for global gene expression changes • Revision of model based on co-culture experiments • Determine host genes regulated by bacteria • siRNA co-culture experiment to test revised network Acknowledgements
Support from: Dariia Vyshenska Dr. Richard Rodrigues Dr. Xiaoxi Dong Dr. Jialu Hu Dr. Andrey Morgun Dr. Natalia Shulzhenko Dr. Heidi Lyng Lab Group Funding: OSU College of Pharmacy E.R. Jackman Internship Support USDA Multicultural Scholars Program Undergraduate Research, Scholarship, and the Arts Undergraduate Research, Innovation, Scholarship & Creativity The microbiome of cervical cancer: exploring the link between bacteria and tumor
Data
In vitro/vivo Network Experiment Reconstruction Cervical Cancer Microbiome
Network Interrogation