Abstract 6102: Streptococcus sp. VT_162 infection of colon cancer cell lines induces mRNAs that associate with poor prognosis
Authors: Brim Hassan , Boulares Hamid , Daremipouran Mohammad , Lee Edward , Ashktorab Hassan 
Published: September 2020

Background: Streptococcus sp. VT_162 (SPV) were identified by our group showed neoplastic transformation in patients with colorectal cancer (CRC). This strain's genome contains 10 virulence factors that match S. pyogenes and 3 different strains of S. pneumomia virulence factors. Hence, we aimed to determine whether (SPV) influences the expression of carcinogenic genes in several human colon cell lines.

Methods: colon cell lines (HCT116, SW480 and LoVo) were infected with (SPV) at a multiplicity of infection (MOI) of 10 or 50.RNA extracts were used on an Illumina sequencer and the mRNA expression profiles were compared to cells that were not exposed to (SPV). Sequencing data were processed according to our previous studies. CutAdapt was used to trim Illumina adapters. Reads were aligned to the UCSC hg38 reference sequence using Bowtie2. Sequencing reads were assembled and annotated. To estimate differential expression between different samples, the count data were used in DESeq2 R package and the comparisons were performed. mRNAs with statistically significant (p&lt;0.05) expression difference from untreated cell lines and log 2 FC &gt;3 are reported and the relation to cancer of the most upregulated mRNAs was investigated.

Results: An in-silico analysis of (SPV) genome revealed that the strain contains ten (10) putative virulence factors that match those of S. pyogenes and three (3) of different strains of S. pneumomia. A MOI of 10, a total of 427 mRNAs displayed a &gt;3 fold upregulation of their expression. The top 20 upregulated genes were: HSPA6, CSF2, SPRR2D, SERPINB7, CXCL8, LCN2, SBSN, HSPA7, SERPINA3, SLC6A12, RSPH10B, ITGAM, BCRP3, CRYAB, GCM1, TNFRSF9, IGFN1, SNAI2, LUCAT1 and SASH3 with the following respective fold differences: 8.44, 6.75, 6.68, 6.56, 6.23, 5.91, 5.81, 5.56, 5.25, 5.21, 5.19, 5.12, 5.06, 5.03, 5.02, 5.01, 4.99, 4.97, 4.93, 4.91, most have shown involve in many other aggressive cancer, poor survival and prognosis. Three of these mRNA HSPA6, HSPA7 and CRAB are heat shock proteins reflecting that the bacterium is perceived as a stressor to the cells. Some of the upregulated mRNA have no known roles and might correspond to novel, specifically-SPV carcinogenic pathways.

Conclusion: SPV infection led to major alterations in the genome expression profiles in the colon cell lines. Many of the upregulated mRNA have known carcinogenic effects and associate with poor prognosis and survival in different organ systems. These findings increase our understanding on the targets by which (SPV) contributes to colorectal cancer transformation and need to be validated in clinical specimens.

Citation Format: Hassan Brim, Hamid Boulares, Mohammad Daremipouran, Edward Lee, Hassan Ashktorab. Streptococcus sp. VT_162 infection of colon cancer cell lines induces mRNAs that associate with poor prognosis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6102.