Chandipura virus induces cell death in cancer cell lines of human origin and promotes tumor regression in vivo

Abstract

Chandipura virus (CHPV) is an emerging human pathogen of great clinical significance. In this study, we have investigated the susceptibility pattern of both normal and cancer cell lines of human origin to wild-type (wt) CHPV in order to explore the possibility of developing CHPV as an oncolytic vector (OV). Marked cytopathic effect along with enhanced virus output was observed in cancer cell lines (HeLa, A549, U-138, PC-3, and HepG2) in comparison to normal human adult dermal fibroblast (HADF) cells. At an MOI of 0.1, cancer cell lines were differentially susceptible to CHPV, with cells like HeLa and U-138 having pronounced cell death, while the PC-3 were comparatively resistant. All cell lines used in the study except U-138 restricted CHPV infection to varying degrees with IFN-β pre-treatment and supplementation of interferon (IFN) could neither activate the IFN signaling pathway in U-138 cells. Finally, U-138 tumor xenografts established in non-obese diabetic severe combined immunodeficiency (NOD/SCID) mice showed significant delay in tumor growth in the CHPV-challenged animals. Thus, targeted cytopathic effect in cancer cells at a very low dose with restricted replication in normal cells offers a rationale to exploit CHPV as an oncolytic vector in the future.

Chandipura Virus forms cytoplasmic inclusion bodies through phase separation and proviral association of cellular protein Kinase R and stress granules protein TIA-1

“…in ∼5% of cells; which by 7 hrs P.I., could be detected in ∼90 % (Fig S1A-B). CHPV infection is known to induce apoptosis in a variety of mammalian host cells, although to a varying degree (37, 38). To understand a correlation between roundening and apoptosis in CHPV infected Vero cells, we employed a commonly used tetrazolium dye based MTT assay to assess the cellular metabolic activity.…”

“…In this direction, we published a report emphasizing on the varying degree of disorder in all five CHPV proteins, with the maximum level of intrinsic disorder propensity found in Phosphoprotein (P) (5). To further investigate the propensity of CHPV proteins for phase separation and for exploration of its host factor usage, a Vero cell line, as reported earlier (38), was investigated as a suitable host system for CHPV replication. While the cytotoxicity assay on CHPV infected cells helped to understand the time frame and dynamics of CHPV gene expression (Fig.…”

“…in ~5% of cells; which by 7 hrs P.I., could be detected in ~90 % (Fig S1A -B). CHPV infection is known to induce apoptosis in a variety of mammalian host cells, although to a varying degree (37,38).To understand a correlation between roundening and apoptosis in CHPV infected Vero cells, we employed a commonly used tetrazolium dye based MTT assay to assess L protein, albeit expressed exclusively in the form of puncta, colocalized with large punctas of N (Fig. 1B,1D-E, S1D), suggesting these to be the CHPV inclusion bodies, herein referred as "CHPV-IBs" or "IBs".…”

Chandipura Virus Forms Cytoplasmic Inclusion Bodies through Phase Separation and Proviral Association of Cellular Protein Kinase R and Stress Granule Protein TIA-1

“…In this direction, we published a report emphasizing the varying degrees of disorder in all five CHPV proteins, with the maximum level of intrinsic disorder propensity found in phosphoprotein (P) [5]. To further investigate the propensity of CHPV proteins for phase separation and for exploration of its host factor usage, a Vero cell line, as reported earlier [38], was investigated as a suitable host system for CHPV replication. While the cytotoxicity assay on CHPV-infected cells helped to understand the timeframe and dynamics of CHPV gene expression (Figure S1), IFA on these cells allowed us to monitor condensation and punctate localization of viral proteins to form CHPV-IBs (Figure 1).…”

“…in ~5% of cells; by 7 h P.I., this could be detected in ~90% (Figure S1A,B). CHPV infection is known to induce apoptosis in a variety of mammalian host cells, although to varying degrees [37,38]. To understand the correlation between roundening and apoptosis in CHPV-infected Vero cells, we employed a commonly used tetrazolium dye based MTT assay to assess the cellular metabolic activity.…”