Persistent Morbillivirus Infection Leads to Altered Cortactin Distribution in Histiocytic Sarcoma Cells with Decreased Cellular Migration Capacity

Abstract

Histiocytic sarcomas represent rare but fatal neoplasms in humans. Based on the absence of a commercially available human histiocytic sarcoma cell line the frequently affected dog displays a suitable translational model. Canine distemper virus, closely related to measles virus, is a highly promising candidate for oncolytic virotherapy. Therapeutic failures in patients are mostly associated with tumour invasion and metastasis often induced by misdirected cytoskeletal protein activities. Thus, the impact of persistent canine distemper virus infection on the cytoskeletal protein cortactin, which is frequently overexpressed in human cancers with poor prognosis, was investigated in vitro in a canine histiocytic sarcoma cell line (DH82). Though phagocytic activity, proliferation and apoptotic rate were unaltered, a significantly reduced migration activity compared to controls (6 hours and 1 day after seeding) accompanied by a decreased number of cortactin mRNA transcripts (1 day) was detected. Furthermore, persistently canine distemper virus infected DH82 cells showed a predominant diffuse intracytoplasmic cortactin distribution at 6 hours and 1 day compared to controls with a prominent membranous expression pattern (p ≤ 0.05). Summarized, persistent canine distemper virus infection induces reduced tumour cell migration associated with an altered intracellular cortactin distribution, indicating cytoskeletal changes as one of the major pathways of virus-associated inhibition of tumour spread.

Oxidative Stress in Canine Histiocytic Sarcoma Cells Induced by an Infection with Canine Distemper Virus Led to a Dysregulation of HIF-1α Downstream Pathway Resulting in a Reduced Expression of VEGF-B In Vitro

“…Canine histiocytic sarcoma cells (DH82) persistently infected with CDV-Ond display a complete spontaneous tumor regression when xenotransplanted subcutaneously into Scid mice [11]. Considered that DH82Ond pi cells did not show any difference in growth and apoptotic rate compared to non-infected controls in vitro and during the initial phase after transplantation in vivo [11,20,21], it was assumed that tumor regression of DH82Ond pi xenotransplants was not caused primarily by direct virus-induced cell death alone. Indeed, it seems more likely that secondary effects of the viral infection on the tumor microenvironment [8,23], as similarly reported for Reoviruses [24], account for the complete regression.…”

“…However, a marked protein overexpression of ER-stress markers such as calnexin, calreticulin and CHOP/GADD 153 have been observed in Vero cell and primary rat neurons 36 h post-infection with recombinant A75/17-V CDV [31]. On the other hand, the aforementioned lack of differences in growth and apoptotic rate between non infected and DH82Ond pi cells [20,21] is in line with the hypothesis that a persistent infection with CDV-Ond might be associated with the activation of adaptive and pro-survival pathways to contrast prolonged oxidative stress, as reported in recombinant HeLa cells expressing silkworm storage protein 1 [54]. The hypothesis of the present study is further supported by the finding of an increased expression of ROS-scavenging enzymes in DH82Ond pi cells at both a molecular and protein level, highlighting the plasticity of cancer cells in actively contrasting excessively severe alterations in their redox potential [45,61].…”

“…Since its establishment in 1988 [19], a canine histiocytic sarcoma cell line (DH82 cells) has been commercially available. DH82 cells can be infected by CDV-Ond [12], and have been reported as a promising model for the investigation of viral oncolysis [8,20,21]. Specifically, acute infection of DH82 cells with CDV-Ond in vitro resulted in a prominent cell death at 12 days post infection [12], followed by establishment of persistent infection in tumor cells surviving the acute lytic phase [11].…”

Anti‐tumour activity of oncolytic reovirus against canine histiocytic sarcoma cells

“…To our knowledge, there are few reports about the effects of oncolytic viruses (morbillivirus and ECHO‐7 virus) on canine and human histiocytic sarcoma . Therefore, data on the oncolytic effects of reovirus on histiocytic sarcoma cells are expected to serve as important evidences for the rational use of oncolytic viruses in clinical trials.…”

“…To our knowledge, there are few reports about the effects of oncolytic viruses (morbillivirus and ECHO-7 virus) on canine and human histiocytic sarcoma. [17][18][19] Therefore, data on the oncolytic effects of reovirus on histiocytic sarcoma cells are expected to serve as important evidences for the rational use of oncolytic viruses in clinical trials. In the present study, we examined the oncolytic effects, both in vitro and in vivo, of reovirus on canine histiocytic sarcoma cell lines and on normal DCs derived from healthy dogs.…”