Identification of African Elephant Polyomavirus in wild elephants and the creation of a vector expressing its viral tumor antigens to transform elephant primary cells

Abstract

Wild elephant populations are declining rapidly due to rampant killing for ivory and body parts, range fragmentation, and human-elephant conflict. Wild and captive elephants are further impacted by viruses, including highly pathogenic elephant endotheliotropic herpesviruses. Moreover, while the rich genetic diversity of the ancient elephant lineage is disappearing, elephants, with their low incidence of cancer, have emerged as a surprising resource in human cancer research for understanding the intrinsic cellular response to DNA damage. However, studies on cellular resistance to transformation and herpesvirus reproduction have been severely limited, in part due to the lack of established elephant cell lines to enable in vitro experiments. This report describes creation of a recombinant plasmid, pAelPyV-1-Tag, derived from a wild isolate of African Elephant Polyomavirus (AelPyV-1), that can be used to create immortalized lines of elephant cells. This isolate was extracted from a trunk nodule biopsy isolated from a wild African elephant, Loxodonta africana, in Botswana. The AelPyV-1 genome contains open-reading frames encoding the canonical large (LTag) and small (STag) tumor antigens. We cloned the entire early region spanning the LTag and overlapping STag genes from this isolate into a high-copy vector to construct a recombinant plasmid, pAelPyV-1-Tag, which effectively transformed primary elephant endothelial cells. We expect that the potential of this reagent to transform elephant primary cells will, at a minimum, facilitate study of elephant-specific herpesviruses.

Establishment of Primary Adult Skin Fibroblast Cell Lines from African Savanna Elephants (Loxodonta africana)

“…Hence, they might play a crucial regulatory role in balancing the tightly connected biological processes of cancer and aging in elephants [20,22,31]. African elephant fibroblasts have been used in the molecular analysis of TP53, but also in telomere length studies and for the development of elephant-specific plasmid encoding viral transforming proteins [20,21,34] Interestingly, in the latter studies, the African elephant fibroblasts were mostly sourced from the San Diego Frozen Zoo, which established the cell line from biopsies from the inner thigh at necropsy [20,21,34,35].…”

“…Several studies have used elephant fibroblast cells from the San Diego Zoo to study the cancer suppression mechanisms in elephants [21,34,35]. To the best of our knowledge, no detailed protocol on the establishment of these fibroblast cells from captive zoo elephants has been published thus far.…”

Of Elephants and Other Mammals: A Comparative Review of Reproductive Tumors and Potential Impact on Conservation

“…If the issue can be solved, then this approach perhaps could be the most promising. Primary elephant skin fibroblasts grow well in culture and cells from several elephants are available for reprogramming attempts [ 142 , 144 , 145 , 146 ].…”