NOD/SCID mouse model of canine T‐cell lymphoma with humoral hypercalcaemia of malignancy: cytokine gene expression profiling and in vivo bioluminescent imaging

Abstract

Lymphoma is a malignant neoplasm arising from B or T lymphocytes. In dogs, one-third of lymphomas are highly aggressive multicentric T-cell lymphomas that are often associated with humoral hypercalcaemia of malignancy (HHM). There are no cell lines or animal models to investigate the pathogenesis of T-cell lymphoma and HHM in dogs. We developed the first xenograft model by injecting lymphoma cells from an Irish Wolfhound intraperitoneally into NOD/SCID mice. The mice developed multicentric lymphoma along with HHM and increased parathyroid hormone-related protein (PTHrP) as occurs in dogs with T-cell lymphoma. Using cytokine complementary DNA arrays, we identified genes that have potential implications in the pathogenesis of T-cell lymphoma. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) of T-cell lymphoma samples from hypercalcaemic canine patients showed that PTHrP likely plays a central role in the pathogenesis of HHM and that hypercalcaemia is the result of a combinatorial effect of different hypercalcaemic factors. Finally, we monitored in vivo tumour progression and metastases in the mouse model by transducing the lymphoma cells with a lentiviral vector that encodes a luciferase-yellow fluorescent protein reporter and showed that in vivo trafficking patterns in this model were similar to those seen in dogs. This unique mouse model will be useful for translational research in lymphoma and for investigating the pathogenesis of T-cell lymphoma and HHM in the dog.

Establishment of Five Canine Lymphoma Cell Lines and Tumor Formation in a Xenotransplantation Model

“…These results are consistent with a previous study where canine T-cell lymphoma cell lines were transplanted intraperitoneally into NOD/SCID mice [7]. Since tumor cells were injected intraperitoneally, it is reasonable that the mesentery was often affected, however, why the pancreas was also a primary target in most mice remains unclear.…”

“…Few studies have reported the xenotransplantation of canine lymphoma cells into immunodeficient mice [2,4,7]. Xenotransplantation of tumor cells is a method to elucidate the mechanisms of tumor formation and invasion.…”

Treatment of T cell lymphoma in dogs

“…There is probably no common mechanism, but rather a combination of different cytokines that differs in different patients (Nadella and others 2008). Only dogs that expressed CD4 on lymphoma cells had hypercalcaemia in one study (Ruslander and others 1997).…”

Mechanisms of Humoral Hypercalcemia of Malignancy in Leukemia/Lymphoma

“…Therefore, it was speculated that additional cytokines are involved in the pathogenesis of HHM in dogs with lymphoma (Mellanby et al, 2006;Rosol et al, 1992). In a xenograft mouse model of canine lymphoma, there was increased expression of TNF-in the tumor in vivo (Nadella et al, 2008). Bone histomorphometry indicated that increased osteoclastic bone resorption was the major cause of HHM in these mice.…”

“…A bioluminescent NOD/SCID mouse model of canine T-cell lymphoma and HHM has been developed (Nadella et al, 2008). The mice developed multicentric lymphoma in the mesenteric lymph nodes after intraperitoneal injection of tumor cells.…”