Abstract 2148: Transcriptome analysis reveals antitumorigenic alterations of seven KRAS-related pathways in reovirus-treated colorectal cancer patients
Authors: Fogel Elisha , Samouha Avishai , Goel Sanjay , Maitra Radhashree 
Published: July 2021

Introduction: Reovirus propagates with high efficiency in KRAS mutated colorectal cancer (CRC). About 40-45% of CRC patients possess KRAS mutation. Oncolytic reovirus treatment in combination with chemotherapy was tested in patients possessing KRAS mutated metastatic CRC. This study evaluates the biological responses to reovirus treatment by determining the gene expression patterns in RAS-related signaling pathways.

Methodology: Reovirus was administered as a 60-min intravenous infusion for 5 consecutive days every 28 days, at tissue culture infective dose (TCID50) of 3x1010. Peripheral blood mononuclear cells (PBMC) were isolated from whole blood pre and post reovirus administration at 48hr, Day-8, and Day-15. Clariom D Human Assay was used to determine the expression of vital genes compared to pre-reovirus treatment by RNA sequencing. Using exported sample signals, ΔΔCt method was used to analyze the fold changes of 2,083 genes within seven KRAS-related pathways. Of these genes, 155 had significance, 16 of which were further analyzed. Significance was calculated by students-Two-tail-T test. A hierarchical clustering dendrogram was constructed using Pearson's correlation coefficient.

Results: Fold changes [p&lt;0.05] are normalized to Pre-treatment and compared to untreated controls. Several genes were common to multiple pathways.

Conclusion: Our transcriptome assay displayed that reovirus treatment causes meaningful alterations in gene expression, showing that reovirus is a successful therapy for KRAS mutated CRC. Reovirus in combination with chemotherapy leads to the regression of tumor growth and KRAS mutated CRC cell proliferation. Our results corroborate that reovirus treatment leads to immune responses, which include increased lymphocytic maturation and activity, increased levels of apoptosis, and a decrease in angiogenesis. While reovirus is propagating, NF-κB, SOS1, and RRAS promote this immune response.

Results: Fold Changes of Genes Analyzed with Correlated PathwaysSelected GenesPathways48hr FCD8 FCD15 FCSOS1RAS, MAPK, EGFR, PI3K, Angiogenesis2.49--RRASRAS, MAPK2.24--PIK3CBRAS, PI3K-2.273.16NOS3EGFR, PI3K--0.61MIR 16-2miR In lymphocytes, Angiogenesis--1.7CHORDC1miR In lymphocytes, Angiogenesis1.89-4.54RTN4miR In lymphocytes, Angiogenesis4.66--FAM96AmiR In lymphocytes, Angiogenesis4.54--SYNEmiR In lymphocytes, Angiogenesis-0.780.71ANGPT1Angiogenesis, PI3K-0.62-VEGFBAngiogenesis0.440.280.28NFKBApoptosis/Immune Response, RAS, MAPK, PI3K-191.42NFKB1(NFKB Subunit)Apoptosis/Immune Response, RAS, MAPK, PI3K--1.42NFKB1A (NFKB Subunit)Apoptosis/Immune Response, RAS, MAPK, PI3K-19-JUNApoptosis/Oncogene, MAPK, EGFR--0.69CASP8Apoptosis-2.111.77CASP9Apoptosis, PI3K-1.45-IGF2Apoptosis, PI3K-0.73-

Citation Format: Elisha Fogel, Avishai Samouha, Sanjay Goel, Radhashree Maitra. Transcriptome analysis reveals antitumorigenic alterations of seven KRAS-related pathways in reovirus-treated colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2148.